WorldWideScience

Sample records for abundance species richness

  1. Upscaling species richness and abundances in tropical forests.

    Science.gov (United States)

    Tovo, Anna; Suweis, Samir; Formentin, Marco; Favretti, Marco; Volkov, Igor; Banavar, Jayanth R; Azaele, Sandro; Maritan, Amos

    2017-10-01

    The quantification of tropical tree biodiversity worldwide remains an open and challenging problem. More than two-fifths of the number of worldwide trees can be found either in tropical or in subtropical forests, but only ≈0.000067% of species identities are known. We introduce an analytical framework that provides robust and accurate estimates of species richness and abundances in biodiversity-rich ecosystems, as confirmed by tests performed on both in silico-generated and real forests. Our analysis shows that the approach outperforms other methods. In particular, we find that upscaling methods based on the log-series species distribution systematically overestimate the number of species and abundances of the rare species. We finally apply our new framework on 15 empirical tropical forest plots and quantify the minimum percentage cover that should be sampled to achieve a given average confidence interval in the upscaled estimate of biodiversity. Our theoretical framework confirms that the forests studied are comprised of a large number of rare or hyper-rare species. This is a signature of critical-like behavior of species-rich ecosystems and can provide a buffer against extinction.

  2. Bird species richness and abundance in different forest types at ...

    African Journals Online (AJOL)

    The avifauna of differently disturbed forest types of Kakamega Afrotropical forest were compared from December 2004 to May 2005. A total of 11 220 individual birds comprising of 129 bird species were recorded. Significant differences in abundance of birds among Psidium guajava, Bischoffia javanica, mixed indigenous, ...

  3. Urbanization level and woodland size are major drivers of woodpecker species richness and abundance.

    Directory of Open Access Journals (Sweden)

    Lukasz Myczko

    Full Text Available Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species.

  4. Urbanization level and woodland size are major drivers of woodpecker species richness and abundance.

    Science.gov (United States)

    Myczko, Lukasz; Rosin, Zuzanna M; Skórka, Piotr; Tryjanowski, Piotr

    2014-01-01

    Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland) in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species.

  5. Abundance and species richness of lombric macrofauna in a semi ...

    African Journals Online (AJOL)

    The importance of earthworms for soils has evolved over time. Our study was conducted in the forest of Ouled yagoub (North East Algerian). Sampling at three different altitudes resulted in a total of forty-nine individuals (49) and only three species were identified: Octodrilus complanatus, Allolobophora molleri and ...

  6. Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches

    Directory of Open Access Journals (Sweden)

    Elena L.E.S. Wagner

    2015-12-01

    Full Text Available Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes, live coral cover and patch size (volume. The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus, was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region.

  7. Evolutionary patterns of range size, abundance and species richness in Amazonian angiosperm trees

    Directory of Open Access Journals (Sweden)

    Kyle Dexter

    2016-09-01

    Full Text Available Amazonian tree species vary enormously in their total abundance and range size, while Amazonian tree genera vary greatly in species richness. The drivers of this variation are not well understood. Here, we construct a phylogenetic hypothesis that represents half of Amazonian tree genera in order to contribute to explaining the variation. We find several clear, broad-scale patterns. Firstly, there is significant phylogenetic signal for all three characteristics; closely related genera tend to have similar numbers of species and similar mean range size and abundance. Additionally, the species richness of genera shows a significant, negative relationship with the mean range size and abundance of their constituent species. Our results suggest that phylogenetically correlated intrinsic factors, namely traits of the genera themselves, shape among lineage variation in range size, abundance and species richness. We postulate that tree stature may be one particularly relevant trait. However, other traits may also be relevant, and our study reinforces the need for ambitious compilations of trait data for Amazonian trees. In the meantime, our study shows how large-scale phylogenies can help to elucidate, and contribute to explaining, macroecological and macroevolutionary patterns in hyperdiverse, yet poorly understood regions like the Amazon Basin.

  8. Landscape and Local Correlates of Bee Abundance and Species Richness in Urban Gardens.

    Science.gov (United States)

    Quistberg, Robyn D; Bichier, Peter; Philpott, Stacy M

    2016-03-31

    Urban gardens may preserve biodiversity as urban population densities increase, but this strongly depends on the characteristics of the gardens and the landscapes in which they are embedded. We investigated whether local and landscape characteristics are important correlates of bee (Hymenoptera: Apiformes) abundance and species richness in urban community gardens. We worked in 19 gardens in the California central coast and sampled bees with aerial nets and pan traps. We measured local characteristics (i.e., vegetation and ground cover) and used the USGS National Land Cover Database to classify the landscape surrounding our garden study sites at 2 km scales. We classified bees according to nesting type (i.e., cavity, ground) and body size and determined which local and landscape characteristics correlate with bee community characteristics. We found 55 bee species. One landscape and several local factors correlated with differences in bee abundance and richness for all bees, cavity-nesting bees, ground-nesting bees, and different sized bees. Generally, bees were more abundant and species rich in bigger gardens, in gardens with higher floral abundance, less mulch cover, more bare ground, and with more grass. Medium bees were less abundant in sites surrounded by more medium intensity developed land within 2 km. The fact that local factors were generally more important drivers of bee abundance and richness indicates a potential for gardeners to promote bee conservation by altering local management practices. In particular, increasing floral abundance, decreasing use of mulch, and providing bare ground may promote bees in urban gardens. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. The relative importance of pollinator abundance and species richness for the temporal variance of pollination services.

    Science.gov (United States)

    Genung, Mark A; Fox, Jeremy; Williams, Neal M; Kremen, Claire; Ascher, John; Gibbs, Jason; Winfree, Rachael

    2017-07-01

    The relationship between biodiversity and the stability of ecosystem function is a fundamental question in community ecology, and hundreds of experiments have shown a positive relationship between species richness and the stability of ecosystem function. However, these experiments have rarely accounted for common ecological patterns, most notably skewed species abundance distributions and non-random extinction risks, making it difficult to know whether experimental results can be scaled up to larger, less manipulated systems. In contrast with the prolific body of experimental research, few studies have examined how species richness affects the stability of ecosystem services at more realistic, landscape scales. The paucity of these studies is due in part to a lack of analytical methods that are suitable for the correlative structure of ecological data. A recently developed method, based on the Price equation from evolutionary biology, helps resolve this knowledge gap by partitioning the effect of biodiversity into three components: richness, composition, and abundance. Here, we build on previous work and present the first derivation of the Price equation suitable for analyzing temporal variance of ecosystem services. We applied our new derivation to understand the temporal variance of crop pollination services in two study systems (watermelon and blueberry) in the mid-Atlantic United States. In both systems, but especially in the watermelon system, the stronger driver of temporal variance of ecosystem services was fluctuations in the abundance of common bee species, which were present at nearly all sites regardless of species richness. In contrast, temporal variance of ecosystem services was less affected by differences in species richness, because lost and gained species were rare. Thus, the findings from our more realistic landscapes differ qualitatively from the findings of biodiversity-stability experiments. © 2017 by the Ecological Society of America.

  10. The effect of peatland drainage and restoration on Odonata species richness and abundance.

    Science.gov (United States)

    Elo, Merja; Penttinen, Jouni; Kotiaho, Janne S

    2015-04-09

    Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration efforts. Here, we studied how abundance and species richness of Odonata (dragonflies and damselflies) respond to restoration. We sampled larvae in three sites (restored, drained, pristine) on each of 12 different study areas. We sampled Odonata larvae before restoration (n = 12), during the first (n = 10) and the third (n = 7) year after restoration and used generalized linear mixed models to analyze the effect of restoration. Drained sites had lower abundance and species richness than pristine sites. During the third year after restoration both abundance and species richness had risen in restored sites. Our results show that Odonata suffer from drainage, but seem to benefit from peatland restoration and are able to colonize newly formed water pools already within three years after restoration.

  11. The impact of land abandonment on species richness and abundance in the Mediterranean Basin

    DEFF Research Database (Denmark)

    Plieninger, Tobias; Hui, Cang; Gaertner, Mirijam

    2014-01-01

    species richness and abundance in agroforestry, arable land, pastures, and permanent crops of the Mediterranean Basin. In particular, we investigated (1) which taxonomic groups (arthropods, birds, lichen, vascular plants) are more affected by land abandonment; (2) at which spatial and temporal scales.......0001) plant and animal species richness and abundance overall, though results were heterogeneous, with differences in effect size between taxa, spatial-temporal scales, land uses, landforms, and climate. In conclusion, there is no "one-size-fits-all" conservation approach that applies to the diverse contexts......Land abandonment is common in the Mediterranean Basin, a global biodiversity hotspot, but little is known about its impacts on biodiversity. To upscale existing case-study insights to the Pan-Mediterranean level, we conducted a metaanalysis of the effects of land abandonment on plant and animal...

  12. Facilitation influences patterns of perennial species abundance and richness in a subtropical dune system.

    Science.gov (United States)

    Dalotto, Cecilia E S; Sühs, Rafael B; Dechoum, Michele S; Pugnaire, Francisco I; Peroni, Nivaldo; Castellani, Tânia T

    2018-04-01

    Positive interactions in plant communities are under-reported in subtropical systems most likely because they are not identified as stressful environments. However, environmental factors or disturbance can limit plant growth in any system and lead to stressful conditions. For instance, salinity and low nutrient and water availability generate a gradient of stressful conditions in coastal systems depending on distance to shore. In a tropical coastal system in SE Brazil, we aimed to assess whether Guapira opposita , a shrub common in restinga environments, acted as nurse involved in ecological succession and which factors influenced its facilitation process. We sampled perennial species above 10 cm in height under the canopy of 35 G. opposita individuals and in neighbouring open areas. Shrub height, canopy area and distance to freshwater bodies were measured in the field, and distance to the ocean was obtained from aerial images. In addition, we measured the distance to the closest forest patch as a potential source of seeds. Plant abundance and species richness were higher under the canopy of G. opposita than in open areas. Facilitation by G. opposita was mainly determined by shrub height, which had a positive relationship with woody and bromeliads abundance and species richness while there was no relationship with the other factors. Overall, our data evidence that tropical environments may be highly stressful for plants and that nurse species play a key role in the regeneration of restinga environments, where their presence is critical to maintain ecosystem diversity and function.

  13. Facilitation influences patterns of perennial species abundance and richness in a subtropical dune system

    Science.gov (United States)

    Dalotto, Cecilia E S; Sühs, Rafael B; Dechoum, Michele S; Pugnaire, Francisco I; Peroni, Nivaldo; Castellani, Tânia T

    2018-01-01

    Abstract Positive interactions in plant communities are under-reported in subtropical systems most likely because they are not identified as stressful environments. However, environmental factors or disturbance can limit plant growth in any system and lead to stressful conditions. For instance, salinity and low nutrient and water availability generate a gradient of stressful conditions in coastal systems depending on distance to shore. In a tropical coastal system in SE Brazil, we aimed to assess whether Guapira opposita, a shrub common in restinga environments, acted as nurse involved in ecological succession and which factors influenced its facilitation process. We sampled perennial species above 10 cm in height under the canopy of 35 G. opposita individuals and in neighbouring open areas. Shrub height, canopy area and distance to freshwater bodies were measured in the field, and distance to the ocean was obtained from aerial images. In addition, we measured the distance to the closest forest patch as a potential source of seeds. Plant abundance and species richness were higher under the canopy of G. opposita than in open areas. Facilitation by G. opposita was mainly determined by shrub height, which had a positive relationship with woody and bromeliads abundance and species richness while there was no relationship with the other factors. Overall, our data evidence that tropical environments may be highly stressful for plants and that nurse species play a key role in the regeneration of restinga environments, where their presence is critical to maintain ecosystem diversity and function. PMID:29644027

  14. Restinga forests of the Brazilian coast: richness and abundance of tree species on different soils.

    Science.gov (United States)

    Magnago, Luiz F S; Martins, Sebastião V; Schaefer, Carlos E G R; Neri, Andreza V

    2012-09-01

    The aim of this study was to determine changes in composition, abundance and richness of species along a forest gradient with varying soils and flood regimes. The forests are located on the left bank of the lower Jucu River, in Jacarenema Natural Municipal Park, Espírito Santo. A survey of shrub/tree species was done in 80 plots, 5x25 m, equally distributed among the forests studied. We included in the sampling all individuals with >3.2 cm diameter at breast height (1.30 m). Soil samples were collected from the surface layer (0-10 cm) in each plot for chemical and physical analysis. The results indicate that a significant pedological gradient occurs, which is influenced by varying seasonal groundwater levels. Restinga forest formations showed significant differences in species richness, except for Non-flooded Forest and Non-flooded Forest Transition. The Canonical Correlation Analysis (CCA) showed that some species are distributed along the gradient under the combined influence of drainage, nutrient concentration and physical characteristics of the soil. Regarding the variables tested, flooding seems to be a more limiting factor for the establishment of plant species in Restinga forests than basic soil fertility attributes.

  15. Relative abundance and species richness of cerambycid beetles in partial cut and uncut bottomland hardwood forests

    Science.gov (United States)

    Newell, P.; King, S.

    2009-01-01

    Partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife. However, partial cutting may or may not benefit species dependent on deadwood; harvesting can supplement coarse woody debris in the form of logging slash, but standing dead trees may be targeted for removal. We sampled cerambycid beetles during the spring and summer of 2006 and 2007 with canopy malaise traps in 1- and 2-year-old partial cut and uncut bottomland hardwood forests of Louisiana. We captured a total of 4195 cerambycid beetles representing 65 species. Relative abundance was higher in recent partial cuts than in uncut controls and with more dead trees in a plot. Total species richness and species composition were not different between treatments. The results suggest partial cuts with logging slash left on site increase the abundance of cerambycid beetles in the first few years after partial cutting and that both partial cuts and uncut forest should be included in the bottomland hardwood forest landscape.

  16. Impacts of non-native Norway spruce plantation on abundance and species richness of ground beetles (Coleoptera: Carabidae

    Directory of Open Access Journals (Sweden)

    Z. Elek

    2001-06-01

    Full Text Available The impacts of non-native Norway spruce plantation on the abundance and species richness of carabids were studied in the Bükk National Park in Hungary, central Europe. Pitfall catches from recently established (5 yr old, young (15 yr after planting, middle-aged (30 yr after planting, old Norway spruce Picea abies plantation (50 yr after planting, and a native submontane beech forest (Fagetum sylvaticae as a control stand were compared.

    Our results showed that deciduous forest species decreased significantly in abundance in the plantations, and appeared in high abundance only in the native beech forest. Furthermore, open habitat species increased remarkably in abundance in the recently established plantation. Carabids were significantly more abundant and species rich in the native forest than in the plantations, while differences were not significant among the plantations. Multiple regression between the abundance and species richness of carabids and twelve environmental measurements showed that pH of the soil, herb cover and density of the carabids’ prey had a significant effect in determining abundance and species richness.

    Our results showed that plantation of non-native Norway spruce species had a detrimental effect on the composition of carabid communities and no regeneration could be observed during the growth of plantations even 50 yr after the establishment. This emphasises the importance of an active nature management practice to facilitate the recolonization of the native species.

  17. Species richness and relative abundance of birds in natural and anthropogenic fragments of Brazilian Atlantic forest

    Directory of Open Access Journals (Sweden)

    Luiz dos Anjos

    2004-06-01

    Full Text Available Bird communities were studied in two types of fragmented habitat of Atlantic forest in the State of Paraná, southern Brazil; one consisted of forest fragments that were created as a result of human activities (forest remnants, the other consisted of a set of naturally occurring forest fragments (forest patches. Using quantitative data obtained by the point counts method in 3 forest patches and 3 forest remnants during one year, species richness and relative abundance were compared in those habitats, considering species groups according to their general feeding habits. Insectivores, omnivores, and frugivores presented similar general tendencies in both habitats (decrease of species number with decreasing size and increasing isolation of forest fragment. However, these tendencies were different, when considering the relative abundance data: the trunk insectivores presented the highest value in the smallest patch while the lowest relative abundance was in the smallest remnant. In the naturally fragmented landscape, time permitted that the loss of some species of trunk insectivores be compensated for the increase in abundance of other species. In contrast, the remnants essentially represented newly formed islands that are not yet at equilibrium and where future species losses would make them similar to the patches.Comunidades de aves foram estudadas em duas regiões fragmentadas de floresta Atlântica no Estado do Paraná, sul do Brasil; uma região é constituída de fragmentos florestais que foram criados como resultado de atividades humanas (remanescentes florestais e a outra de um conjunto de fragmentos florestais naturais (manchas de floresta. Usando dados quantitativos (o método de contagens pontuais previamente obtidos em 3 manchas de floresta e em 3 remanescentes florestais durante um ano, a riqueza e a abundância relativa de aves foram comparadas naqueles habitats considerando as espécies pelos seus hábitos alimentares. Inset

  18. Variation in local abundance and species richness of stream fishes in relation to dispersal barriers: Implications for management and conservation

    Science.gov (United States)

    Nislow, K.H.; Hudy, M.; Letcher, B.H.; Smith, E.P.

    2011-01-01

    1.Barriers to immigration, all else being equal, should in principle depress local abundance and reduce local species richness. These issues are particularly relevant to stream-dwelling species when improperly designed road crossings act as barriers to migration with potential impacts on the viability of upstream populations. However, because abundance and richness are highly spatially and temporally heterogeneous and the relative importance of immigration on demography is uncertain, population- and community-level effects can be difficult to detect. 2.In this study, we tested the effects of potential barriers to upstream movements on the local abundance and species richness of a diverse assemblage of resident stream fishes in the Monongahela National Forest, West Virginia, U.S.A. Fishes were sampled using simple standard techniques above- and below road crossings that were either likely or unlikely to be barriers to upstream fish movements (based on physical dimensions of the crossing). We predicted that abundance of resident fishes would be lower in the upstream sections of streams with predicted impassable barriers, that the strength of the effect would vary among species and that variable effects on abundance would translate into lower species richness. 3.Supporting these predictions, the statistical model that best accounted for variation in abundance and species richness included a significant interaction between location (upstream or downstream of crossing) and type (passable or impassable crossing). Stream sections located above predicated impassable culverts had fewer than half the number of species and less than half the total fish abundance, while stream sections above and below passable culverts had essentially equivalent richness and abundance. 4.Our results are consistent with the importance of immigration and population connectivity to local abundance and species richness of stream fishes. In turn, these results suggest that when measured at

  19. Species richness and relative species abundance of Nymphalidae (Lepidoptera in three forests with different perturbations in the North-Central Caribbean of Costa Rica

    Directory of Open Access Journals (Sweden)

    Carolyn Stephen

    2014-09-01

    Full Text Available Measurements of species richness and species abundance can have important implications for regulations and conservation. This study investigated species richness and abundance of butterflies in the family Nymphalidae at undisturbed, and disturbed habitats in Tirimbina Biological Reserve and Nogal Private Reserve, Sarapiquí, Costa Rica. Traps baited with rotten banana were placed in the canopy and the understory of three habitats: within mature forest, at a river/forest border, and at a banana plantation/forest border. In total, 71 species and 487 individuals were caught and identified during May and June 2011 and May 2013. Species richness and species abundance were found to increase significantly at perturbed habitats (p<0.0001, p<0.0001, respectively. The edge effect, in which species richness and abundance increase due to greater complementary resources from different habitats, could be one possible explanation for increased species richness and abundance. Rev. Biol. Trop. 62 (3: 919-928. Epub 2014 September 01.

  20. Plant species richness and abundance in residential yards across a tropical watershed: implications for urban sustainability

    Directory of Open Access Journals (Sweden)

    Cristina P. Vila-Ruiz

    2014-09-01

    Full Text Available Green spaces within residential areas provide important contributions to the sustainability of urban systems. Therefore, studying the characteristics of these areas has become a research priority in cities worldwide. This project evaluated various aspects of the plant biodiversity of residential yards (i.e., front yards and back yards within the Río Piedras watershed in the San Juan metropolitan area of Puerto Rico. Our work included gathering information on vegetation composition and abundance of woody species (i.e., trees, shrubs, palms, ferns and large herbs (>2 m height, species origin (native vs. introduced, and species uses (ornamental, food, and medicinal plants. A total of 424 yards were surveyed within an area of 187,191 m². We found 383 woody species, with shrubs being the most abundant plant habitat. As expected, residential yards hosted a disproportionate amount of introduced species (69.5%. The most common shrub species were all non-native ornamentals, whereas the most common tree species included food trees as well as ornamental plants and two native species. Front yards hosted more ornamental species per unit area than backyards, while the latter had more food plants. The high amount of introduced species may present a challenge in terms of implementation of plant conservation initiatives if there is no clear definition of urban conservation goals. On the other hand, the high frequency of yards containing food plants may facilitate the development of residential initiatives that could provide future adaptive capacity to food shortages.

  1. Species richness and abundance of hesperioidea and papilionoidea (lepidoptera) in Las Delicias natural reserve, Santa Marta, Magdalena, Colombia

    International Nuclear Information System (INIS)

    Vargas Zapata, Maria A; Martinez Hernandez, Neis Jose; Gutierrez Moreno, Luis C and others

    2011-01-01

    In the foothills of the Sierra Nevada de Santa Marta, Colombia, are formations of dry tropical secondary forest hosting a fauna representative of lepidoptera, which can be used as an indicator of group condition, because of their sensitivity to intervention and specificity in the use of resources; in the present study the changes in richness and abundance of butterflies hesperioidea papilionoidea in nature reserve Las Delicias were evaluated. Two sampling sites with different degrees of intervention were selected. The first site is located between 400- 550 over sea level, while the second at 200 m. We performed four samples, from April to July 2008; using two networks lepidopterist and 10 van someren rydon traps baited with macerated fruit and fish. We captured 432 individuals belonging to 66 species, distributed in 52 genera. Nymphalidae were the most rich family (42) and abundance (250); highlighting the species mechanitis lysimnia fabricius (41 specimens), typical in forest with very good coverage. Site 2, was the most diverse (48) and abundance (236), because in this place there was a greater stratification and tree coverage, and the presence of water resources during the sampling. With the arrival of rain in June and July, there was greater flowering and fruiting of vegetation in the area, increasing the availability of resources and therefore a greater richness and abundance of papilionoidea and hesperioidea in the study area.

  2. Higher species richness and abundance of fish and benthic invertebrates around submarine groundwater discharge in Obama Bay, Japan

    OpenAIRE

    Tatsuya Utsunomiya; Masaki Hata; Ryo Sugimoto; Hisami Honda; Shiho Kobayashi; Yoji Miyata; Makoto Yamada; Osamu Tominaga; Jun Shoji; Makoto Taniguchi

    2017-01-01

    Study focus: There have been far more studies on how the variability in surface water discharge affects production of animal communities in aquatic ecosystems while less information has been accumulated on the mechanisms of how the groundwater supply works. Study region: Physical and biological surveys were conducted to test the hypothesis that high level of submarine ground water discharge enhances species richness, abundance and biomass of fishes and invertebrates in coastal waters of Ob...

  3. Effects of habitat-forming species richness, evenness, identity, and abundance on benthic intertidal community establishment and productivity.

    Directory of Open Access Journals (Sweden)

    Julie Lemieux

    Full Text Available In a context of reduced global biodiversity, the potential impacts from the loss of habitat-forming species (HFS on ecosystem structure and functioning must be established. These species are often the main community primary producers and have a major role in the establishment of organisms through facilitation processes. This study focuses on macroalgae and mussels as HFS within an intertidal zone along the St. Lawrence estuary (Quebec, Canada. Over a 16-week period, we manipulated the in situ diversity profile (richness, evenness, identity, and abundance of the dominant HFS (Fucus distichus edentatus, F. vesiculosus, and Mytilus spp. in order to define their role in both the establishment of associated species and community primary production. Contrary to expectation, no general change in HFS richness, evenness, abundance, or identity on associated species community establishment was observed. However, over the study period, the HFS diversity profile modified the structure within the trophic guilds, which may potentially affect further community functions. Also, our results showed that the low abundance of HFS had a negative impact on the primary productivity of the community. Our results suggest that HFS diversity profiles have a limited short-term role in our study habitat and may indicate that biological forcing in these intertidal communities is less important than environmental conditions. As such, there was an opportunistic establishment of species that ensured rapid colonization regardless of the absence, or the diversity profile, of facilitators such as HFS.

  4. Monitoring species richness and abundance of shorebirds in the western Great Basin

    Science.gov (United States)

    Warnock, Nils; Haig, Susan M.; Oring, Lewis W.

    1998-01-01

    Broad-scale avian surveys have been attempted within North America with mixed results. Arid regions, such as the Great Basin, are often poorly sampled because of the vastness of the region, inaccessibility of sites, and few ornithologists. In addition, extreme variability in wetland habitat conditions present special problems for conducting censuses of species inhabiting these areas. We examined these issues in assessing multi-scale shorebird (order: Charadriiformes) censuses conducted in the western Great Basin from 1992-1997. On ground surveys, we recorded 31 species of shorebirds, but were unable to accurately estimate population size. Conversely, on aerial surveys we were able to estimate regional abundance of some shorebirds, but were unable to determine species diversity. Aerial surveys of three large alkali lakes in Oregon (Goose, Summer, and Abert Lakes) revealed > 300,000 shorebirds in one year of this study, of which 67% were American Avocets (Recurvirostra americana) and 30% phalaropes (Phalaropus spp.). These lakes clearly meet Western Hemisphere Shorebird Reserve Network guidelines for designation as important shorebird sites. Based upon simulations of our monitoring effort and the magnitude and variation of numbers of American Avocets, detection of S-10% negative declines in populations of these birds would take a minimum of 7-23 years of comparable effort. We conclude that a combination of ground and aerial surveys must be conducted at multiple sites and years and over a large region to obtain an accurate picture of the diversity, abundance, and trends of shorebirds in the western Great Basin.

  5. Patterns of species richness and abundance among cactus communities receiving different rainfall levels in the semiarid region of Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Monteiro Ferreira

    Full Text Available ABSTRACT This study examines the variation in cacti species richness and abundance among sites with different average rainfall and soil types. We assessed a total of 3,660 individuals of six species of Cactaceae: Cereus jamacaru, Melocactus zehntneri, Pilosocereus gounellei, Pilosocereus pachycladus, Tacinga inamoena, and Tacinga palmadora. The greatest species richness and abundance of cacti were at locations with low rainfall and more clayey soils. The species studied differed in multidimensional representation, with some species being more positively related to soils with a higher proportion of fine particles (M. zehntneri and P. gounellei, while others were negatively related to soils with a higher proportion of coarser particles (T. inamoena or positively related to areas with higher rainfall and vegetation cover (C. jamacaru and P. pachycladus. The differential responses of the species of Cactaceae studied in relation to the gradients analyzed demonstrates the need for more research into the relationship between cacti and environmental variables in semiarid ecosystems with high environmental heterogeneity.

  6. Tree species, spatial heterogeneity, and seasonality drive soil fungal abundance, richness, and composition in Neotropical rainforests.

    Science.gov (United States)

    Kivlin, Stephanie N; Hawkes, Christine V

    2016-12-01

    Tropical ecosystems remain poorly understood and this is particularly true for belowground soil fungi. Soil fungi may respond to plant identity when, for example, plants differentially allocate resources belowground. However, spatial and temporal heterogeneity in factors such as plant inputs, moisture, or nutrients can also affect fungal communities and obscure our ability to detect plant effects in single time point studies or within diverse forests. To address this, we sampled replicated monocultures of four tree species and secondary forest controls sampled in the drier and wetter seasons over 2 years. Fungal community composition was primarily related to vegetation type and spatial heterogeneity in the effects of vegetation type, with increasing divergence partly reflecting greater differences in soil pH and soil moisture. Across wetter versus drier dates, fungi were 7% less diverse, but up to four-fold more abundant. The combined effects of tree species and seasonality suggest that predicted losses of tropical tree diversity and intensification of drought have the potential to cascade belowground to affect both diversity and abundance of tropical soil fungi. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Physical factors affecting the abundance and species richness of fishes in the shallow waters of the southern Bothnian Sea (Sweden)

    Science.gov (United States)

    Thorman, Staffan

    1986-03-01

    The relationship between the composition of the fish assemblages and the abiotic environment in seven shallow areas within the same geographical range in the southern Bothnian Sea were studied in May, July, September and November 1982. Eighteen species were found in the areas and the major species were Pungitius pungitius (L.), Pomatoschistus minutus (Pallas), Gasterosteus aculeatus (L.), Phoxinus phoxinus (L.), Pomatoschistus microps (Krøyer) and Gobius niger L. The main purpose of the study was to examine the possible effects of exposure, organic contents in sediments and habitat heterogeneity on species richness and abundance of the assemblages. There was a negative correlation between the organic contents of the sediment and exposure. There were no significant correlations between exposure, organic contents, size of the areas and species numbers but habitat heterogeneity was positively correlated with species number. There were no correlations between fish abundance and heterogeneity of the areas. Negative correlations occurred between the exposure of the areas and fish abundance. The amounts of the pooled benthic fauna were negatively correlated to the exposure. The species/area hypothesis finds no support in the results, because there was no correlation between habitat heterogeneity of an area and its size. The effective fetch combined with the heterogeneity measurement of the areas seemed to be useful indicators of the species composition and fish abundance. Habitat heterogeneity and exposure were the most important structuring factors of these shallow water fish assemblages during the ice-free period and within the local geographical range. The assemblages consist of a mixture of species with marine or limnic origin and they have probably not evolved in the Bothnian Sea or together. They are most likely regulated by their physiological plasticity and not by interactions with other species.

  8. Species richness and abundance of bats in fragments of the stational semidecidual forest, Upper Paraná River, southern Brazil

    Directory of Open Access Journals (Sweden)

    H. Ortêncio-Filho

    Full Text Available The Upper Paraná River floodplain is inserted in a region of the Mata Atlântica biome, which is a critical area to preserve. Due to the scarcity of researches about the chiropterofauna in this region, the present study investigated species richness and abundance of bats in remnants from the stational semidecidual forest of the Upper Paraná River, southern Brazil. Samplings were taken every month, from January to December 2006, using 32 mist nets with 8.0 x 2.5 m, resulting in 640 m²/h and totaling a capture effort of 87,040 m²/h. In order to estimate the species richness, the following estimators were employed Chao1 and Jack2. During the study, a total of 563 individuals belonging to 17 species (Artibeus planirostris, Artibeus lituratus, Carollia perspicillata, Platyrrhinus lineatus, Sturnira lilium, Artibeus fimbriatus, Myotis nigricans, Desmodus rotundus, Artibeus obscurus, Noctilio albiventris, Phylostomus discolor, Phylostomus hastatus, Chrotopterus auritus, Lasiurus ega, Chiroderma villosum, Pygoderma bilabiatum and Lasiurus blossevillii were captured. The estimated richness curves tended to stabilize, indicating that most of the species were sampled. Captured species represented 10% of the taxa recorded in Brazil and 28% in Paraná State, revealing the importance of this area for the diversity of bats. These findings indicate the need to determine actions aiming to restrict human activities in these forest fragments, in order to minimize anthropogenic impacts on the chiropterofauna.

  9. Simulated geographic variations of plant species richness, evenness and abundance using climatic constraints on plant functional diversity

    International Nuclear Information System (INIS)

    Kleidon, Axel; Pavlick, Ryan; Reu, Bjoern; Adams, Jonathan

    2009-01-01

    Among the most pronounced large-scale geographic patterns of plant biodiversity are the increase in plant species richness towards the tropics, a more even distribution of the relative abundances of plant species in the tropics, and a nearly log-normal relative abundance distribution. Here we use an individual-based plant diversity model that relates climatic constraints to feasible plant growth strategies to show that all three basic diversity patterns can be predicted merely from the climatic constraints acting upon plant ecophysiological trade-offs. Our model predicts that towards objectively 'harsher' environments, the range of feasible growth strategies resulting in reproductive plants is reduced, thus resulting in lower functional plant species richness. The reduction of evenness is attributed to a more rapid decline in productivity from the most productive to less productive plant growth strategies since the particular setup of the strategy becomes more important in maintaining high productivity in harsher environments. This approach is also able to reproduce the increase in the deviation from a log-normal distribution towards more evenly distributed communities of the tropics. Our results imply that these general biodiversity relationships can be understood primarily by considering the climatic constraints on plant ecophysiological trade-offs.

  10. Regional Variation in Parasite Species Richness and Abundance in the Introduced Range of the Invasive Lionfish, Pterois volitans.

    Science.gov (United States)

    Sellers, Andrew J; Ruiz, Gregory M; Leung, Brian; Torchin, Mark E

    2015-01-01

    Parasites can play an important role in biological invasions. While introduced species often lose parasites from their native range, they can also accumulate novel parasites in their new range. The accumulation of parasites by introduced species likely varies spatially, and more parasites may shift to new hosts where parasite diversity is high. Considering that parasitism and disease are generally more prevalent at lower latitudes, the accumulation of parasites by introduced hosts may be greater in tropical regions. The Indo-Pacific lionfish (Pterois volitans) has become widely distributed across the Western Atlantic. In this study, we compared parasitism across thirteen locations in four regions, spanning seventeen degrees of latitude in the lionfish's introduced range to examine potential spatial variation in parasitism. In addition, as an initial step to explore how indirect effects of parasitism might influence interactions between lionfish and ecologically similar native hosts, we also compared parasitism in lionfish and two co-occurring native fish species, the graysby grouper, Cephalopholis cruentata, and the lizardfish, Synodus intermedius, in the southernmost region, Panama. Our results show that accumulation of native parasites on lionfish varies across broad spatial scales, and that colonization by ectoparasites was highest in Panama, relative to the other study sites. Endoparasite richness and abundance, on the other hand, were highest in Belize where lionfish were infected by twice as many endoparasite species as lionfish in other regions. The prevalence of all but two parasite species infecting lionfish was below 25%, and we did not detect an association between parasite abundance and host condition, suggesting a limited direct effect of parasites on lionfish, even where parasitism was highest. Further, parasite species richness and abundance were significantly higher in both native fishes compared to lionfish, and parasite abundance was negatively

  11. Regional Variation in Parasite Species Richness and Abundance in the Introduced Range of the Invasive Lionfish, Pterois volitans.

    Directory of Open Access Journals (Sweden)

    Andrew J Sellers

    Full Text Available Parasites can play an important role in biological invasions. While introduced species often lose parasites from their native range, they can also accumulate novel parasites in their new range. The accumulation of parasites by introduced species likely varies spatially, and more parasites may shift to new hosts where parasite diversity is high. Considering that parasitism and disease are generally more prevalent at lower latitudes, the accumulation of parasites by introduced hosts may be greater in tropical regions. The Indo-Pacific lionfish (Pterois volitans has become widely distributed across the Western Atlantic. In this study, we compared parasitism across thirteen locations in four regions, spanning seventeen degrees of latitude in the lionfish's introduced range to examine potential spatial variation in parasitism. In addition, as an initial step to explore how indirect effects of parasitism might influence interactions between lionfish and ecologically similar native hosts, we also compared parasitism in lionfish and two co-occurring native fish species, the graysby grouper, Cephalopholis cruentata, and the lizardfish, Synodus intermedius, in the southernmost region, Panama. Our results show that accumulation of native parasites on lionfish varies across broad spatial scales, and that colonization by ectoparasites was highest in Panama, relative to the other study sites. Endoparasite richness and abundance, on the other hand, were highest in Belize where lionfish were infected by twice as many endoparasite species as lionfish in other regions. The prevalence of all but two parasite species infecting lionfish was below 25%, and we did not detect an association between parasite abundance and host condition, suggesting a limited direct effect of parasites on lionfish, even where parasitism was highest. Further, parasite species richness and abundance were significantly higher in both native fishes compared to lionfish, and parasite

  12. The use of bird species richness and abundance indices to assess ...

    African Journals Online (AJOL)

    The East Usambaras are within the Eastern Afromontane hotspot, which is known for its exceptionally rich biodiversity. The original forest of the East Usambaras has been reduced by human activities, including establishment of Eucalyptus plantations, but little is known about the value of these plantations for biodiversity.

  13. Effects of landscape composition and wetland fragmentation on frog and toad abundance and species richness in Iowa and Wisconsin, USA

    Science.gov (United States)

    Knutson, M.G.; Sauer, J.R.; Olsen, D.A.; Mossman, M.J.; Hemesath, L.M.; Lannoo, M.J.

    1999-01-01

    Management of amphibian populations to reverse recent declines will require defining high-quality habitat for individual species or groups of species, followed by efforts to retain or restore these habitats on the landscape. We examined landscape-level habitat relationships for frogs and toads by measuring associations between relative abundance and species richness based on survey data derived from anuran calls and features of land-cover maps for Iowa and Wisconsin. The most consistent result across all anuran guilds was a negative association with the presence of urban land. Upland and wetland forests and emergent wetlands tended to be positively associated with anurans. Landscape metrics that represent edges and patch diversity also had generally positive associations, indicating that anurans benefit from a complex of habitats that include wetlands. In Iowa the most significant associations with relative abundance were the length of the edge between wetland and forest (positive) and the presence of urban land (negative). In Wisconsin the two most significant associations with relative abundance were forest area and agricultural area (both positive). Anurans had positive associations with agriculture in Wisconsin but not in Iowa. Remnant forest patches in agricultural landscapes may be providing refuges for some anuran species. Differences in anuran associations with deep water and permanent wetlands between the two states suggest opportunities for management action. Large-scale maps can contribute to predictive models of amphibian habitat use, but water quality and vegetation information collected from individual wetlands will likely be needed to strengthen those predictions. Landscape habitat analyses provide a framework for future experimental and intensive research on specific factors affecting the health of anurans.

  14. Abundance and species richness of snakes along the Middle Rio Grande riparian forest in New Mexico

    Science.gov (United States)

    Heather L. Bateman; Alice Chung-MacCoubrey; Howard L. Snell; Deborah M. Finch

    2009-01-01

    To understand the effects of removal of non-native plants and fuels on wildlife in the riparian forest of the Middle Rio Grande in New Mexico, we monitored snakes from 2000 to 2006 using trap arrays of drift fences, pitfalls, and funnel traps. We recorded 158 captures of 13 species of snakes from 12 study sites. We captured more snakes in funnel traps than in pitfalls...

  15. The effect of peatland drainage and restoration on Odonata species richness and abundance

    OpenAIRE

    Elo, Merja; Penttinen, Jouni; Kotiaho, Janne Sakari

    2015-01-01

    Background Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration effo...

  16. Can Airborne Laser Scanning (ALS and Forest Estimates Derived from Satellite Images Be Used to Predict Abundance and Species Richness of Birds and Beetles in Boreal Forest?

    Directory of Open Access Journals (Sweden)

    Eva Lindberg

    2015-04-01

    Full Text Available In managed landscapes, conservation planning requires effective methods to identify high-biodiversity areas. The objective of this study was to evaluate the potential of airborne laser scanning (ALS and forest estimates derived from satellite images extracted at two spatial scales for predicting the stand-scale abundance and species richness of birds and beetles in a managed boreal forest landscape. Multiple regression models based on forest data from a 50-m radius (i.e., corresponding to a homogenous forest stand had better explanatory power than those based on a 200-m radius (i.e., including also parts of adjacent stands. Bird abundance and species richness were best explained by the ALS variables “maximum vegetation height” and “vegetation cover between 0.5 and 3 m” (both positive. Flying beetle abundance and species richness, as well as epigaeic (i.e., ground-living beetle richness were best explained by a model including the ALS variable “maximum vegetation height” (positive and the satellite-derived variable “proportion of pine” (negative. Epigaeic beetle abundance was best explained by “maximum vegetation height” at 50 m (positive and “stem volume” at 200 m (positive. Our results show that forest estimates derived from satellite images and ALS data provide complementary information for explaining forest biodiversity patterns. We conclude that these types of remote sensing data may provide an efficient tool for conservation planning in managed boreal landscapes.

  17. Three dimensional marine seismic survey has no measurable effect on species richness or abundance of a coral reef associated fish community

    International Nuclear Information System (INIS)

    Miller, Ian; Cripps, Edward

    2013-01-01

    Highlights: • A marine seismic survey was conducted at Scott Reef, North Western Australia. • Effects of the survey on demersal fish were gauged using underwater visual census. • There was no detectable impact of the seismic survey on species abundance. • There was no detectable impact of the seismic survey on species richness. -- Abstract: Underwater visual census was used to determine the effect of a three dimensional seismic survey on the shallow water coral reef slope associated fish community at Scott Reef. A census of the fish community was conducted on six locations at Scott Reef both before and after the survey. The census included small site attached demersal species belonging to the family Pomacentridae and larger roving demersal species belonging to the non-Pomacentridae families. These data were combined with a decade of historical data to assess the impact of the seismic survey. Taking into account spatial, temporal, spatio-temporal and observer variability, modelling showed no significant effect of the seismic survey on the overall abundance or species richness of Pomacentridae or non-Pomacentridae. The six most abundant species were also analysed individually. In all cases no detectable effect of the seismic survey was found on the abundance of these fish species at Scott Reef

  18. Preliminary Estimate of Earthworm Abundance and Species Richness in Spathodea campanulata Beauv. Forests in Northern Puerto Rico

    Science.gov (United States)

    ARIEL E. LUGO; OSCAR J. ABELLEIRA; SONIA BORGES; LAUREN J. COLÓN; SYNDI MELÉNDEZ; MARIELA A. RODRÍGUEZ

    2006-01-01

    The alien tree species Spathodea campanulata forms monodominant stands in abandoned agricultural lands in Puerto Rico. In July 2005, we excavated three replicate randomly located soil pits (25 by 25 by 30 cm) in each of six stands of Spathodea. Three of the stands were located in the moist alluvial geoclimatic zone and three were in the moist karst geoclimatic zone,...

  19. Riqueza, abundância e sazonalidade de Sphingidae (Lepidoptera num fragmento de Mata Atlântica de Pernambuco, Brasil Species richness, abundance and seasonality of Sphingidae (Lepidoptera in a fragment of Atlantic Rainforest of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    José A. Duarte Júnior

    2005-09-01

    Full Text Available Na Mata Atlântica de Pernambuco, NE-Brasil (Reserva Biológica de Gurjaú, Cabo de Santo Agostinho foi realizado um levantamento de Sphingidae de dezembro de 2002 a novembro de 2003. Os esfingídeos foram coletados com luz de vapor de mercúrio durante duas noites consecutivas por mês, próximo ao novilúnio. Foram determinadas riqueza de espécies, abundância e sazonalidade. Oitenta e nove espécimes de 23 espécies em 13 gêneros foram registrados; 84% dos indivíduos foram machos. Muitas espécies foram raras e de 13 espécies foi coletado apenas um exemplar. Xylophanes loelia (Druce, 1878, X. libya (Druce, 1878, Hemeroplanes triptolemus (Cramer, 1779, Eumorpha anchemolus (Cramer, 1779, Manduca brasilensis (Jordan, 1911, M. hannibal (Cramer, 1779, Adhemarius gannascus (Stoll, 1790 e Protambulyx astygonus (Boisduval, [1875] foram registradas pela primeira vez no Nordeste do Brasil. A esfingofauna não mostrou nenhum padrão de sazonalidade, e riqueza e abundância de espécies de esfingídeos não se correlacionaram com precipitação mensal e temperatura.In the Atlantic Rainforest of Pernambuco, NE-Brazil (Reserva Biológica de Gurjaú, Cabo de Santo Agostinho a survey of Sphingidae was performed from December 2002 to November 2003. The hawkmoths were collected with vapor mercury light during two consecutive nights per months near new moon. Species richness, abundance and seasonality were determined. Eighty-nine specimens of 23 species in13 genera were recorded; 84% the individuals were males. Most species were rare and from 13 species only one exemplar was collected. Xylophanes loelia (Druce, 1878, X. libya (Druce, 1878, Hemeroplanes triptolemus (Cramer, 1779, Eumorpha anchemolus (Cramer, 1779, Manduca brasilensis (Jordan, 1911, M. hannibal (Cramer, 1779, Adhemarius gannascus (Stoll, 1790 e Protambulyx astygonus (Boisduval, [1875] were recorded for the first time in Northeastern Brazil. The sphingofauna showed no seasonal patterns and

  20. Shredders are abundant and species-rich in tropical continental-island low-order streams: Gorgona Island, Tropical Eastern Pacific, Colombia

    Directory of Open Access Journals (Sweden)

    Magnolia Longo

    2014-02-01

    Full Text Available Macroinvertebrate shredders may have been overlooked in tropical streams due to the geographical bias of early studies, methodological limitations, and the complex influences of local-scale factors. While shredders seem to be scarce in most oceanic island streams, we here test if they are abundant in a continental island. Gut content analyses of benthic macroinvertebrates were used to identify shredding taxa in streams located in different types of forest in Gorgona Island (Tropical Eastern Pacific. General dietary overlap (GO was quantified and relative biomass, relative frequency and the leaf litter percentage in the guts were used to establish the relative importance of each taxon in the shredding guild. Various indices were used to identify the spatial arrangement (i.e. contagious or random of each taxon and shredding guild among streams. We identified 31 shredding taxa that were divided into specialist-shredders (14 taxa, generalist-shredders (10, and collector-shredders (7. There was a complete GO (0.75, p<0.001 for the guild. Cockroaches (Epilampra were the most represented shredders due to the greatest contribution to guild total biomass and to the highest content of leaf litter in their guts. These organisms were more important than shrimps and crabs in terms of abundance and biomass in leaf pack samples. Potimirin shrimps ranked second and Stenochironomus midges ranked third. Among aquatic insects, other secondarily important species were Leptohyphes (Ephemeroptera, Macrelmis, Anchytarsus and Tetraglosa (Coleoptera. Ten taxa exhibited contagious spatial pattern and twenty-one exhibited a random distribution. Resource distribution (i.e., leaf packs between streams was random too. The guild was contagiously distributed, but this result could be highly influenced by the taxa with contagious distribution. Mean abundance, richness and mean biomass of shredders were not significantly correlated with any of the environmental variables

  1. The invasive ant, Solenopsis invicta, reduces herpetofauna richness and abundance

    Science.gov (United States)

    Allen, Craig R.; Birge, Hannah E.; Slater, J.; Wiggers, E.

    2017-01-01

    Amphibians and reptiles are declining globally. One potential cause of this decline includes impacts resulting from co-occurrence with non-native red imported fire ant, Solenopsis invicta. Although a growing body of anecdotal and observational evidence from laboratory experiments supports this hypothesis, there remains a lack of field scale manipulations testing the effect of fire ants on reptile and amphibian communities. We addressed this gap by measuring reptile and amphibian (“herpetofauna”) community response to successful fire ant reductions over the course of 2 years following hydramethylnon application to five 100–200 ha plots in southeastern coastal South Carolina. By assessing changes in relative abundance and species richness of herpetofauna in response to fire ant reductions, we were able to assess whether some species were particularly vulnerable to fire ant presence, and whether this sensitivity manifested at the community level. We found that herpetofauna abundance and species richness responded positively to fire ant reductions. Our results document that even moderate populations of red imported fire ants decrease both the abundance and diversity of herpetofauna. Given global herpetofauna population declines and continued spread of fire ants, there is urgency to understand the impacts of fire ants beyond anecdotal and singles species studies. Our results provides the first community level investigation addressing these dynamics, by manipulating fire ant abundance to reveal a response in herpetofauna species abundance and richness.

  2. Arbuscular Mycorrhizal Fungi Community Structure, Abundance and Species Richness Changes in Soil by Different Levels of Heavy Metal and Metalloid Concentration

    Science.gov (United States)

    Krishnamoorthy, Ramasamy; Kim, Chang-Gi; Subramanian, Parthiban; Kim, Ki-Yoon; Selvakumar, Gopal; Sa, Tong-Min

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) play major roles in ecosystem functioning such as carbon sequestration, nutrient cycling, and plant growth promotion. It is important to know how this ecologically important soil microbial player is affected by soil abiotic factors particularly heavy metal and metalloid (HMM). The objective of this study was to understand the impact of soil HMM concentration on AMF abundance and community structure in the contaminated sites of South Korea. Soil samples were collected from the vicinity of an abandoned smelter and the samples were subjected to three complementary methods such as spore morphology, terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Spore density was found to be significantly higher in highly contaminated soil compared to less contaminated soil. Spore morphological study revealed that Glomeraceae family was more abundant followed by Acaulosporaceae and Gigasporaceae in the vicinity of the smelter. T-RFLP and DGGE analysis confirmed the dominance of Funneliformis mosseae and Rhizophagus intraradices in all the study sites. Claroideoglomus claroideum, Funneliformis caledonium, Rhizophagus clarus and Funneliformis constrictum were found to be sensitive to high concentration of soil HMM. Richness and diversity of Glomeraceae family increased with significant increase in soil arsenic, cadmium and zinc concentrations. Our results revealed that the soil HMM has a vital impact on AMF community structure, especially with Glomeraceae family abundance, richness and diversity. PMID:26035444

  3. Attenuation of species abundance distributions by sampling

    Science.gov (United States)

    Shimadzu, Hideyasu; Darnell, Ross

    2015-01-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  4. Floral abundance, richness, and spatial distribution drive urban garden bee communities.

    Science.gov (United States)

    Plascencia, M; Philpott, S M

    2017-10-01

    In urban landscapes, gardens provide refuges for bee diversity, but conservation potential may depend on local and landscape features. Foraging and population persistence of bee species, as well as overall pollinator community structure, may be supported by the abundance, richness, and spatial distribution of floral resources. Floral resources strongly differ in urban gardens. Using hand netting and pan traps to survey bees, we examined whether abundance, richness, and spatial distribution of floral resources, as well as ground cover and garden landscape surroundings influence bee abundance, species richness, and diversity on the central coast of California. Differences in floral abundance and spatial distribution, as well as urban cover in the landscape, predicted different bee community variables. Abundance of all bees and of honeybees (Apis mellifera) was lower in sites with more urban land cover surrounding the gardens. Honeybee abundance was higher in sites with patchy floral resources, whereas bee species richness and bee diversity was higher in sites with more clustered floral resources. Surprisingly, bee species richness and bee diversity was lower in sites with very high floral abundance, possibly due to interactions with honeybees. Other studies have documented the importance of floral abundance and landscape surroundings for bees in urban gardens, but this study is the first to document that the spatial arrangement of flowers strongly predicts bee abundance and richness. Based on these findings, it is likely that garden managers may promote bee conservation by managing for floral connectivity and abundance within these ubiquitous urban habitats.

  5. Species richness alone does not predict cultural ecosystem service value

    Science.gov (United States)

    Graves, Rose A.; Pearson, Scott M.; Turner, Monica G.

    2017-01-01

    Many biodiversity-ecosystem services studies omit cultural ecosystem services (CES) or use species richness as a proxy and assume that more species confer greater CES value. We studied wildflower viewing, a key biodiversity-based CES in amenity-based landscapes, in Southern Appalachian Mountain forests and asked (i) How do aesthetic preferences for wildflower communities vary with components of biodiversity, including species richness?; (ii) How do aesthetic preferences for wildflower communities vary across psychographic groups?; and (iii) How well does species richness perform as an indicator of CES value compared with revealed social preferences for wildflower communities? Public forest visitors (n = 293) were surveyed during the summer of 2015 and asked to choose among images of wildflower communities in which flower species richness, flower abundance, species evenness, color diversity, and presence of charismatic species had been digitally manipulated. Aesthetic preferences among images were unrelated to species richness but increased with more abundant flowers, greater species evenness, and greater color diversity. Aesthetic preferences were consistent across psychographic groups and unaffected by knowledge of local flora or value placed on wildflower viewing. When actual wildflower communities (n = 54) were ranked based on empirically measured flower species richness or wildflower viewing utility based on multinomial logit models of revealed preferences, rankings were broadly similar. However, designation of hotspots (CES values above the median) based on species richness alone missed 27% of wildflower viewing utility hotspots. Thus, conservation priorities for sustaining CES should incorporate social preferences and consider multiple dimensions of biodiversity that underpin CES supply. PMID:28320953

  6. Time-averaged molluscan death assemblages: Palimpsests of richness, snapshots of abundance

    Science.gov (United States)

    Kidwell, Susan M.

    2002-09-01

    Field tests that compare living communities to associated dead remains are the primary means of estimating the reliability of biological information in the fossil record; such tests also provide insights into the dynamics of skeletal accumulation. Contrary to expectations, molluscan death assemblages capture a strong signal of living species' rank-order abundances. This finding, combined with independent evidence for exponential postmortem destruction of dead cohorts, argues that, although the species richness of a death assemblage may be a time-averaged palimpsest of the habitat (molluscan death assemblages contain, on average, ˜25% more species than any single census of the local live community, after sample-size standardization), species' relative-abundance data from the same assemblage probably constitute a much higher acuity record dominated by the most recent dead cohorts (e.g., from the past few hundred years or so, rather than the several thousand years recorded by the total assemblage and usually taken as the acuity of species-richness information). The pervasive excess species richness of molluscan death assemblages requires further analysis and modeling to discriminate among possible sources. However, time averaging alone cannot be responsible unless rare species (species with low rates of dead-shell production) are collectively more durable (have longer taphonomic half-lives) than abundant species. Species richness and abundance data thus appear to present fundamentally different taphonomic qualities for paleobiological analysis. Relative- abundance information is more snapshot-like and thus taphonomically more straightforward than expected, especially compared to the complex origins of dead-species richness.

  7. Book review: A new view on the species abundance distribution

    Science.gov (United States)

    DeAngelis, Donald L.

    2018-01-01

    The sampled relative abundances of species of a taxonomic group, whether birds, trees, or moths, in a natural community at a particular place vary in a way that suggests a consistent underlying pattern, referred to as the species abundance distribution (SAD). Preston [1] conjectured that the numbers of species, plotted as a histogram of logarithmic abundance classes called octaves, seemed to fit a lognormal distribution; that is, the histograms look like normal distributions, although truncated on the left-hand, or low-species-abundance, end. Although other specific curves for the SAD have been proposed in the literature, Preston’s lognormal distribution is widely cited in textbooks and has stimulated attempts at explanation. An important aspect of Preston’s lognormal distribution is the ‘veil line’, a vertical line drawn exactly at the point of the left-hand truncation in the distribution, to the left of which would be species missing from the sample. Dewdney rejects the lognormal conjecture. Instead, starting with the long-recognized fact that the number of species sampled from a community, when plotted as histograms against population abundance, resembles an inverted J, he presents a mathematical description of an alternative that he calls the ‘J distribution’, a hyperbolic density function truncated at both ends. When multiplied by species richness, R, it becomes the SAD of the sample.

  8. Forested landscapes promote richness and abundance of native bees (Hymenoptera: Apoidea: Anthophila) in Wisconsin apple orchards.

    Science.gov (United States)

    Watson, J C; Wolf, A T; Ascher, J S

    2011-06-01

    Wild bees provide vital pollination services for many native and agricultural plant species, yet the landscape conditions needed to support wild bee populations are not well understood or appreciated. We assessed the influence of landscape composition on bee abundance and species richness in apple (Malus spp.) orchards of northeastern Wisconsin during the spring flowering period. A diverse community of bee species occurs in these apple orchards, dominated by wild bees in the families Andrenidae and Halictidae and the honey bee, Apis mellifera L. Proportion of forest area in the surrounding landscape was a significant positive predictor of wild bee abundance in orchards, with strongest effects at a GIS (Geographic Information Systems) buffer distance of 1,000 m or greater. Forest area also was positively associated with species richness, showing strongest effects at a buffer distance of 2,000 m. Nonagricultural developed land (homes, lawns, etcetera) was significantly negatively associated with species richness at buffer distances >750 m and wild bee abundance in bowl traps at all distances. Other landscape variables statistically associated with species richness or abundance of wild bees included proportion area of pasture (positive) and proportion area of roads (negative). Forest area was not associated with honey bee abundance at any buffer distance. These results provide clear evidence that the landscape surrounding apple orchards, especially the proportion of forest area, affects richness and abundance of wild bees during the spring flowering period and should be a part of sustainable land management strategies in agro-ecosystems of northeastern Wisconsin and other apple growing regions.

  9. Bracken: estimating species abundance in metagenomics data

    Directory of Open Access Journals (Sweden)

    Jennifer Lu

    2017-01-01

    Full Text Available Metagenomic experiments attempt to characterize microbial communities using high-throughput DNA sequencing. Identification of the microorganisms in a sample provides information about the genetic profile, population structure, and role of microorganisms within an environment. Until recently, most metagenomics studies focused on high-level characterization at the level of phyla, or alternatively sequenced the 16S ribosomal RNA gene that is present in bacterial species. As the cost of sequencing has fallen, though, metagenomics experiments have increasingly used unbiased shotgun sequencing to capture all the organisms in a sample. This approach requires a method for estimating abundance directly from the raw read data. Here we describe a fast, accurate new method that computes the abundance at the species level using the reads collected in a metagenomics experiment. Bracken (Bayesian Reestimation of Abundance after Classification with KrakEN uses the taxonomic assignments made by Kraken, a very fast read-level classifier, along with information about the genomes themselves to estimate abundance at the species level, the genus level, or above. We demonstrate that Bracken can produce accurate species- and genus-level abundance estimates even when a sample contains multiple near-identical species.

  10. Clonal growth and plant species abundance.

    Science.gov (United States)

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-08-01

    Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf-height-seed) traits and by actual performance in the botanical garden. Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area - height - seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially underlying clonal growth effects on abundance. Garden

  11. Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands

    Science.gov (United States)

    Keeley, Jon E.

    2003-01-01

    Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species-area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small-stature annual species in California and the lack of annuals in Australian heathlands. Species-area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species-area curves initially rise rapidly between 1 and 100 m2. Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m2 but more rapidly between 100 and 1000 m2due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species-area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species-area curves, and this may be tied to patterns of life form distribution.

  12. Species Richness and Diversity Reveal that Human-Modified ...

    African Journals Online (AJOL)

    Family diversity and richness showed no significant differences across the sites. The spider species consisted of primarily three functional groups: ground wanderers, web builders and plant wanderers, and showed no within-group differences in abundance between sites. Similarity index between the study sites revealed a ...

  13. Pollinator species richness: Are the declines slowing down?

    Directory of Open Access Journals (Sweden)

    Tom J. M. Van Dooren

    2016-09-01

    Full Text Available Changes in pollinator abundances and diversity are of major concern. A recent study inferred that pollinator species richnesses are decreasing more slowly in recent decades in several taxa and European countries. A more careful interpretation of these results reveals that this conclusion cannot be drawn and that we can only infer that declines decelerate for bees (Anthophila in the Netherlands.

  14. Island Species Richness Increases with Habitat Diversity

    NARCIS (Netherlands)

    Hortal, J.; Triantis, K.A.; Meiri, S.; Thebault, E.M.C.; Sfenthourakis, S.

    2009-01-01

    Species richness is commonly thought to increase with habitat diversity. However, a recent theoretical model aiming to unify niche and island biogeography theories predicted a hump-shaped relationship between richness and habitat diversity. Given the contradiction between model results and previous

  15. The influence of temperature and humidity on abundance and richness of Calliphoridae (Diptera

    Directory of Open Access Journals (Sweden)

    Rodrigo R. Azevedo

    2013-06-01

    Full Text Available The blowfly species are important components in necrophagous communities of the Neotropics. Besides being involved in the degradation of animal organic matter, they may serve as vectors for pathogens and parasites, and also cause primary and secondary myiasis. The occurrence pattern of these species is well defined, yet it is still not very clear which of these environmental factors determine the structure of the assemblies. This paper was developed to evaluate the influence of mean temperature and relative humidity variation in the abundance and richness of blowflies in the Brazilian southernmost state, Rio Grande do Sul, where temperature variation is well marked throughout the year. To evaluate this objective, WOT (Wind Oriented Trap were installed with beef liver as bait in three environments for 10 consecutive days in each month between July 2003 and June 2004. A total of 13,860 flies were collected distributed among 16 species with a higher frequency of Lucilia eximia (Wiedemann, 1819 and Chrysomya albiceps (Wiedemann, 1819. The mean temperature and relative humidity influence the richness of blowflies, with greater richness and abundance in late spring and early summer, whereas abundance was only influenced by temperature. Each species responded differently with respect to these variables, where L. eximia is not influenced by any of the two abiotic factors, despite the high abundance presented. This paper presents the results of the sensitivity for the presence or absence of species of Calliphoridae and on the variation of the abundance of these species under regime temperature changes and relative humidity with implications for public health and animal management.

  16. A global database of ant species abundances

    Science.gov (United States)

    Gibb, Heloise; Dunn, Rob R.; Sanders, Nathan J.; Grossman, Blair F.; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N.; Angulo, Elena; Armbrecht, Ingre; Arnan, Xavier; Baccaro, Fabricio B.; Bishop, Tom R.; Boulay, Raphael; Bruhl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A.; Ellison, Aaron M.; Enriquez, Martha L.; Fayle, Tom M.; Feener Jr., Donald H.; Fisher, Brian L.; Fisher, Robert N.; Fitpatrick, Matthew C.; Gomez, Cristanto; Gotelli, Nicholas J.; Gove, Aaron; Grasso, Donato A.; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H.; Majer, Jonathan; McGlynn, Terrence P.; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M.; Resasco, Julian; Retana, Javier; Silva, Rogerio R.; Sorger, Magdalena D.; Souza, Jorge; Suarez, Andrew V.; Tista, Melanie; Vasconcelos, Heraldo L.; Vonshak, Merav; Weiser, Michael D.; Yates, Michelle; Parr, Catherine L.

    2017-01-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardised methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing dataset.

  17. Forms and genesis of species abundance distributions

    Directory of Open Access Journals (Sweden)

    Evans O. Ochiaga

    2015-12-01

    Full Text Available Species abundance distribution (SAD is one of the most important metrics in community ecology. SAD curves take a hollow or hyperbolic shape in a histogram plot with many rare species and only a few common species. In general, the shape of SAD is largely log-normally distributed, although the mechanism behind this particular SAD shape still remains elusive. Here, we aim to review four major parametric forms of SAD and three contending mechanisms that could potentially explain this highly skewed form of SAD. The parametric forms reviewed here include log series, negative binomial, lognormal and geometric distributions. The mechanisms reviewed here include the maximum entropy theory of ecology, neutral theory and the theory of proportionate effect.

  18. A biogeographical perspective on species abundance distributions

    DEFF Research Database (Denmark)

    Matthews, Thomas J.; Borges, Paulo A. V.; de Azevedo, Eduardo Brito

    2017-01-01

    It has become increasingly recognized that multiple processes can generate similar shapes of species abundance distributions (SADs), with the result that the fit of a given SAD model cannot unambiguously provide evidence in support of a given theory or model. An alternative approach to comparing...... the fit of different SAD models to data from a single site is to collect abundance data from a variety of sites, and then build models to analyse how different SAD properties (e.g. form, skewness) vary with different predictor variables. Such a biogeographical approach to SAD research is potentially very...... revealing, yet there has been a general lack of interest in SADs in the biogeographical literature. In this Perspective, we address this issue by highlighting findings of recent analyses of SADs that we consider to be of intrinsic biogeographical interest. We use arthropod data drawn from the Azorean...

  19. A new species of Trichoderma hypoxylon harbours abundant secondary metabolites.

    Science.gov (United States)

    Sun, Jingzu; Pei, Yunfei; Li, Erwei; Li, Wei; Hyde, Kevin D; Yin, Wen-Bing; Liu, Xingzhong

    2016-11-21

    Some species of Trichoderma are fungicolous on fungi and have been extensively studied and commercialized as biocontrol agents. Multigene analyses coupled with morphology, resulted in the discovery of T. hypoxylon sp. nov., which was isolated from surface of the stroma of Hypoxylon anthochroum. The new taxon produces Trichoderma- to Verticillium-like conidiophores and hyaline conidia. Phylogenetic analyses based on combined ITS, TEF1-α and RPB2 sequence data indicated that T. hypoxylon is a well-distinguished species with strong bootstrap support in the polysporum group. Chemical assessment of this species reveals a richness of secondary metabolites with trichothecenes and epipolythiodiketopiperazines as the major compounds. The fungicolous life style of T. hypoxylon and the production of abundant metabolites are indicative of the important ecological roles of this species in nature.

  20. Richness and Abundance of Ichneumonidae in a Fragmented Tropical Rain Forest.

    Science.gov (United States)

    Ruiz-Guerra, B; Hanson, P; Guevara, R; Dirzo, R

    2013-10-01

    Because of the magnitude of land use currently occurring in tropical regions, the local loss of animal species due to habitat fragmentation has been widely studied, particularly in the case of vertebrates. Many invertebrate groups and the ichneumonid wasps in particular, however, have been poorly studied in this context, despite the fact that they are one of the most species-rich groups and play an important role as regulators of other insect populations. Here, we recorded the taxonomic composition of ichneumonid parasitoids and assessed their species richness, abundance, similarity, and dominance in the Los Tuxtlas tropical rain forest, Mexico. We compared two forest types: a continuous forest (640 ha) and a forest fragment (19 ha). We sampled ichneumonids using four malaise traps in both forest types during the dry (September-October) and rainy (March-April) seasons. A total of 104 individuals of Ichneumonidae belonging to 11 subfamilies, 18 genera, and 42 species were collected in the continuous forest and 11 subfamilies, 15 genera, and 24 species were collected in the forest fragment. Species richness, abundance, and diversity of ichneumonids were greater in the continuous forest than in the forest fragment. We did not detect differences between seasons. Species rank/abundance curves showed that the ichneumonid community between the forest types was different. Species similarity between forest types was low. The most dominant species in continuous forest was Neotheronia sp., whereas in the forest fragment, it was Orthocentrus sp. Changes in the ichneumonid wasp community may compromise important tropical ecosystem processes.

  1. Local and Landscape Drivers of Parasitoid Abundance, Richness, and Composition in Urban Gardens.

    Science.gov (United States)

    Burks, Julia M; Philpott, Stacy M

    2017-04-01

    Urbanization negatively affects biodiversity, yet some urban habitat features can support diversity. Parasitoid wasps, an abundant and highly diverse group of arthropods, can inhabit urban areas and do well in areas with higher host abundance, floral resources, or local or landscape complexity. Parasitoids provide biological control services in many agricultural habitats, yet few studies have examined diversity and abundance of parasitoids in urban agroecosystems to understand how to promote conservation and function. We examined the local habitat and landscape drivers of parasitoid abundance, superfamily and family richness, and parasitoid composition in urban gardens in the California central coast. Local factors included garden size, ground cover type, herbaceous plant species, and number of trees and shrubs. Landscape characteristics included land cover and landscape diversity around gardens. We found that garden size, mulch cover, and urban cover within 500 m of gardens predicted increases in parasitoid abundance within gardens. The height of herbaceous vegetation and tree and shrub richness predicted increases in superfamily and family richness whereas increases in urban cover resulted in declines in parasitoid richness. Abundance of individual superfamilies and families responded to a wide array of local and landscape factors, sometimes in opposite ways. Composition of parasitoid communities responded to changes in garden size, herbaceous plant cover, and number of flowers. Thus, both local scale management and landscape planning may impact the abundance, diversity, and community composition of parasitoids in urban gardens, and may result in differences in the effectiveness of parasitoids in biological control. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Species richness in natural and disturbed habitats: Asteraceae and Flower-head insects (Tephritidae: Diptera).

    Science.gov (United States)

    Diniz, Soraia; Prado, Paulo I; Lewinsohn, Thomas M

    2010-01-01

    Anthropogenic changes in the landscape result in an environmental mosaic with serious consequences for biodiversity. The aim of the present study was to assess the effects of the anthropogenic changes on Asteraceae richness and abundance, and to evaluate the consequences for the richness of Tephritidae assemblages in five sampling sites, with three sampled habitats in each: cerrado (Brazilian savanna), eucalyptus stands and pasture. Sampling was carried out in 15 random transects (cerrados and one pasture) and in 30 transects (eucalyptus stands and the remaining pastures). Composition, species richness and insect abundance in each habitat type was estimated by sampling the flower heads for each species of host plant, collected by four people for 1h. Differences in mean abundance of plant population between habitats and sites were tested by two-way ANOVA. Differences in plant species richness between habitats and sites and effects of habitat, site and host plant richness on insect richness were tested using a generalized linear model with Poisson errors. Within each sampling site, cerrados showed higher species richness of Asteraceae than pastures and eucalyptus stands. There were also significant differences in plant richness among sites. Mean population abundance values were significantly different among habitats, but not among sites. Increased host plant richness led to significant insect species richness. There were no additional significant effects of habitat on insect richness. Therefore, anthropogenic alterations in landscape determined the impoverishment of plant assemblages and therefore of insect assemblages, because of the positive relationship between host plant richness and insect richness.

  3. Abundance of introduced species at home predicts abundance away in herbaceous communities

    Science.gov (United States)

    Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  4. Species richness, area and climate correlates

    DEFF Research Database (Denmark)

    Nogues, David Bravo; Bastos Araujo, Miguel

    2006-01-01

    affects: (1) the selection of climate variables entering a species richness model; and (2) the accuracy of models in predicting species richness in unsampled grid cells. Location Western Europe. Methods Models are developed for European plant, breeding bird, mammal and herptile species richness using...... seven climate variables. Generalized additive models are used to relate species richness, climate and area. Results We found that variation in the grid cell area was large (50 × 50 km: 8-3311 km2; 220 × 220: 193-55,100 km2), but this did not affect the selection of variables in the models. Similarly...... support the assumption that variation in near-equal area cells may be of second-order importance for models explaining or predicting species richness in relation to climate, although there is a possibility that drops in accuracy might increase with grid cell size. The results are, however, contingent...

  5. Efeito das atividades de ecoturismo sobre a riqueza e a abundância de espécies de mamíferos de médio e grande porte na região do Cristalino, Mato Grosso, Brasil Effect of ecotourism activities on richness and abundance of species of medium and large mammals in the Cristalino region, Mato Grosso, Brazil

    Directory of Open Access Journals (Sweden)

    Ednaldo Cândido Rocha

    2012-12-01

    , empreendimentos de ecoturismo se apresentam como importante atividade econômica a ser desenvolvida em áreas com potencial turístico na Amazônia.This study was carried out in the Private Natural Heritage Reserves Lote Cristalino (670 ha, Cristalino (6,539 ha and in Cristalino State Park (184,900 ha. These protected areas are contiguous and are located in the extreme north-central State of Mato Grosso, in areas considered priorities for conservation due to the high biodiversity and endemism and the high human pressure. Thus, this study focused to evaluate and compare the structure of populations of medium and large mammals in terms of richness and abundance in environments without tourism and with ecotourism activities in Cristalino region. Therefore, in the period from May 2008 to February 2010, primary forest environments with two levels of anthropogenic disturbance were sampled: no tourism at all and ecotourism activities. Data were collected by using the distance samplings in linear transect, totalizing 468,3 kilometers traveled during daytime and nighttime, and the record of footprints in previously prepared plots (n = 660 surveyed plots, in addition to river corridors in Cristalino River and random searches in places with difficult access due to the lack of roads. Records of 37 species of mammals were obtained, which 33 were medium and large size and four small ones. There was no statistically significant difference in species richness of the environments without tourism and with ecotourism, and the similarity of species among them was quite high (88%. However, three taxa were less abundant in environments with tourism: Dasyprocta leporina (Linnaeus, 1766, Mazama spp. and Dasypus kappleri Krauss, 1862. Therefore, it can be observed that the negative impact of ecotourism activities developed in the study area presented a small magnitude, in terms of richness and abundance of medium and large mammals. Thus, ecotourism ventures are presented as important economic activity to

  6. Taxonomic richness and abundance of cryptic peracarid crustaceans in the Puerto Morelos Reef National Park, Mexico

    Directory of Open Access Journals (Sweden)

    Luz Veronica Monroy-Velázquez

    2017-06-01

    Full Text Available Background and Aims Cryptic peracarids are an important component of the coral reef fauna in terms of diversity and abundance, yet they have been poorly studied. The aim of this study was to evaluate the taxonomic richness and abundance of cryptic peracarids in coral rubble in the Puerto Morelos Reef National Park, Mexico (PMRNP, and their relationship with depth. Methods Three reef sites were selected: (1 Bonanza, (2 Bocana, and (3 Jardines. At each site six kilograms of coral rubble were collected over four sampling periods at three depths: 3 m (back-reef, 6–8 m (fore-reef, and 10–12 m (fore-reef. Results A total of 8,887 peracarid crustaceans belonging to 200 taxa distributed over five orders and 63 families was obtained; 70% of the taxa were identified to species and 25% to genus level. Fifty species of those collected represent new records for the Mexican Caribbean Sea. Isopoda was the most speciose order while Tanaidacea was the most abundant. Discussion Cryptic peracarid taxonomic richness and abundance were related to depth with higher values of both parameters being found in the shallow (3 m back-reef, possibly due to a higher reef development and a greater accumulation of coral rubble produced during hurricanes. Peracarid data obtained in the present study can be used as a baseline for future monitoring programs in the PMRNP.

  7. Indirect effects of predators control herbivore richness and abundance in a benthic eelgrass (Zostera marina) mesograzer community.

    Science.gov (United States)

    Amundrud, Sarah L; Srivastava, Diane S; O'Connor, Mary I

    2015-07-01

    Herbivore communities can be sensitive to changes in predator pressure (top-down effects) and resource availability (bottom-up effects) in a wide range of systems. However, it remains unclear whether such top-down and bottom-up effects reflect direct impacts of predators and/or resources on herbivores, or are indirect, reflecting altered interactions among herbivore species. We quantified direct and indirect effects of bottom-up and top-down processes on an eelgrass (Zostera marina) herbivore assemblage. In a field experiment, we factorially manipulated water column nutrients (with Osmocote(™) slow-release fertilizer) and predation pressure (with predator exclusion cages) and measured the effects on herbivore abundance, richness and beta diversity. We examined likely mechanisms of community responses by statistically exploring the response of individual herbivore species to trophic manipulations. Predators increased herbivore richness and total abundance, in both cases through indirect shifts in community composition. Increases in richness occurred through predator suppression of common gammarid amphipod species (Monocorophium acherusicum and Photis brevipes), permitting the inclusion of rarer gammarid species (Aoroides columbiae and Pontogeneia rostrata). Increased total herbivore abundance reflected increased abundance of a caprellid amphipod species (Caprella sp.), concurrent with declines in the abundance of other common species. Furthermore, predators decreased beta diversity by decreasing variability in Caprella sp. abundance among habitat patches. Osmocote(™) fertilization increased nutrient concentrations locally, but nutrients dissipated to background levels within 3 m of the fertilizer. Nutrient addition weakly affected the herbivore assemblage, not affecting richness and increasing total abundance by increasing one herbivore species (Caprella sp.). Nutrient addition did not affect beta diversity. We demonstrated that assemblage-level effects of

  8. Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar.

    Science.gov (United States)

    Belchior, Ceres; Sendoya, Sebastián F; Del-Claro, Kleber

    2016-01-01

    Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m2), in the rainy (October-January) and dry seasons (April-July) of 2010-2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.

  9. Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar.

    Directory of Open Access Journals (Sweden)

    Ceres Belchior

    Full Text Available Plants bearing extrafloral nectaries (EFNs are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1 EFN-bearing plants are more visited by ants than EFN-lacking plants; 2 ant visitation is higher in the rainy season than in dry season; 3 plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4 during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5 the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m2, in the rainy (October-January and dry seasons (April-July of 2010-2011. Plants (72 species; 762 individuals were checked three times per season for ant presence. Results showed that 21 species (29% and 266 individuals (35% possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season. In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.

  10. Evaluation of NDVI to assess avian abundance and richness along the upper San Pedro River

    Science.gov (United States)

    McFarland, T.M.; van Riper, Charles; Johnson, G.E.

    2012-01-01

    Remote-sensing models have become increasingly popular for identifying, characterizing, monitoring, and predicting avian habitat but have largely focused on single bird species. The Normalized Difference Vegetation Index (NDVI) has been shown to positively correlate with avian abundance and richness and has been successfully applied to southwestern riparian systems which are uniquely composed of narrow bands of vegetation in an otherwise dry landscape. Desert riparian ecosystems are important breeding and stopover sites for many bird species but have been degraded due to altered hydrology and land management practices. Here we investigated the use of NDVI, coupled with vegetation, to model the avian community structure along the San Pedro River, Arizona. We also investigated how vegetation and physical features measured locally compared to those data that can be gathered through remote-sensing. We found that NDVI has statistically significant relationships with both avian abundance and species richness, although is better applied at the individual species level. However, the amount of variation explained by even our best models was quite low, suggesting that NDVI habitat models may not presently be an accurate tool for extensive modeling of avian communities. We suggest additional studies in other watersheds to increase our understanding of these bird/NDVI relationships.

  11. Patterns of Freshwater Species Richness, Endemism, and Vulnerability in California.

    Directory of Open Access Journals (Sweden)

    Jeanette K Howard

    Full Text Available The ranges and abundances of species that depend on freshwater habitats are declining worldwide. Efforts to counteract those trends are often hampered by a lack of information about species distribution and conservation status and are often strongly biased toward a few well-studied groups. We identified the 3,906 vascular plants, macroinvertebrates, and vertebrates native to California, USA, that depend on fresh water for at least one stage of their life history. We evaluated the conservation status for these taxa using existing government and non-governmental organization assessments (e.g., endangered species act, NatureServe, created a spatial database of locality observations or distribution information from ~400 data sources, and mapped patterns of richness, endemism, and vulnerability. Although nearly half of all taxa with conservation status (n = 1,939 are vulnerable to extinction, only 114 (6% of those vulnerable taxa have a legal mandate for protection in the form of formal inclusion on a state or federal endangered species list. Endemic taxa are at greater risk than non-endemics, with 90% of the 927 endemic taxa vulnerable to extinction. Records with spatial data were available for a total of 2,276 species (61%. The patterns of species richness differ depending on the taxonomic group analyzed, but are similar across taxonomic level. No particular taxonomic group represents an umbrella for all species, but hotspots of high richness for listed species cover 40% of the hotspots for all other species and 58% of the hotspots for vulnerable freshwater species. By mapping freshwater species hotspots we show locations that represent the top priority for conservation action in the state. This study identifies opportunities to fill gaps in the evaluation of conservation status for freshwater taxa in California, to address the lack of occurrence information for nearly 40% of freshwater taxa and nearly 40% of watersheds in the state, and to

  12. Seasonal patterns of horse fly richness and abundance in the Pampa biome of southern Brazil.

    Science.gov (United States)

    Krüger, Rodrigo Ferreira; Krolow, Tiago Kütter

    2015-12-01

    Fluctuations in seasonal patterns of horse fly populations were examined in rainforests of tropical South America, where the climate is seasonal. These patterns were evaluated with robust analytical models rather than identifying the main factors that influenced the fluctuations. We examined the seasonality of populations of horse flies in fields and lowland areas of the Pampa biome of southern Brazil with generalized linear models. We also investigated the diversity of these flies and the sampling effort of Malaise traps in this biome over two years. All of the 29 species had clear seasonality with regard to occurrence and abundance, but only seven species were identified as being influenced by temperature and humidity. The sampling was sufficient and the estimated diversity was 10% more than observed. Seasonal trends were synchronized across species and the populations were most abundant between September and March and nearly zero in other months. While previous studies demonstrated that seasonal patterns in population fluctuations are correlated with climatic conditions in horse fly assemblages in South America rainforests, we show a clear effect of each factor on richness and abundance and the seasonality in the prevalence of horse fly assemblages in localities of the Pampa biome. © 2015 The Society for Vector Ecology.

  13. Estimating tree species richness from forest inventory plot data

    Science.gov (United States)

    Ronald E. McRoberts; Dacia M. Meneguzzo

    2007-01-01

    Montreal Process Criterion 1, Conservation of Biological Diversity, expresses species diversity in terms of number of forest dependent species. Species richness, defined as the total number of species present, is a common metric for analyzing species diversity. A crucial difficulty in estimating species richness from sample data obtained from sources such as inventory...

  14. Geographical range and local abundance of tree species in China.

    Directory of Open Access Journals (Sweden)

    Haibao Ren

    Full Text Available Most studies on the geographical distribution of species have utilized a few well-known taxa in Europe and North America, with little research in China and its wide range of climate and forest types. We assembled large datasets to quantify the geographic ranges of tree species in China and to test several biogeographic hypotheses: 1 whether locally abundant species tend to be geographically widespread; 2 whether species are more abundant towards their range-centers; and 3 how abundances are correlated between sites. Local abundances of 651 species were derived from four tree plots of 20-25 ha where all individuals ≥1 cm in stem diameter were mapped and identified taxonomically. Range sizes of these species across China were then estimated from over 460,000 geo-referenced records; a Bayesian approach was used, allowing careful measures of error of each range estimate. The log-transformed range sizes had a bell-shaped distribution with a median of 703,000 km(2, and >90% of 651 species had ranges >10(5 km(2. There was no relationship between local abundance and range size, and no evidence for species being more abundant towards their range-centers. Finally, species' abundances were positively correlated between sites. The widespread nature of most tree species in China suggests few are vulnerable to global extinction, and there is no indication of the double-peril that would result if rare species also had narrow ranges.

  15. Species identification, distribution and abundance of Gerreidae ...

    African Journals Online (AJOL)

    the distribution and abundance of Gerres in estuaries wa'S collected from July 1978 to ..... the channel area between the W.L.R. and the mouth (not the tidal basin) during ..... overwhelming importance in the kelp beds of Britain. Recently Blaber ...

  16. Use of abundance of one species as a surrogate for abundance of others

    Science.gov (United States)

    Samuel A. Cushman; Kevin S. McKelvey; Barry R. Noon; Kevin McGarigal

    2010-01-01

    Indicator species concepts have a long history in conservation biology. Arguments in favor of these approaches generally stress expediency and assume efficacy. We tested the premise that the abundance patterns of one species can be used to infer those of other species. Our data consisted of 72,495 bird observations on 55 species across 1046 plots distributed across 30...

  17. The implicit assumption of symmetry and the species abundance distribution

    NARCIS (Netherlands)

    Alonso, D.; Ostling, A.; Etienne, R.S.

    2008-01-01

    Species abundance distributions (SADs) have played a historical role in the development of community ecology. They summarize information about the number and the relative abundance of the species encountered in a sample from a given community. For years ecologists have developed theory to

  18. The implicit assumption of symmetry and the species abundance distribution

    NARCIS (Netherlands)

    Alonso, David; Ostling, Annette; Etienne, Rampal S.

    Species abundance distributions (SADs) have played a historical role in the development of community ecology. They summarize information about the number and the relative abundance of the species encountered in a sample from a given community. For years ecologists have developed theory to

  19. Molecular Abundances in the Circumstellar Envelope of Oxygen-Rich Supergiant VY Canis Majoris

    Science.gov (United States)

    Edwards, Jessica L.; Ziurys, Lucy

    2014-06-01

    A complete set of molecular abundances have been established for the Oxygen-rich circumstellar envelope (CSE) surrounding the supergiant star VY Canis Majoris (VY CMa). These data were obtained from The Arizona Radio Observatory (ARO) 1-mm spectral line survey of this object using the ARO Sub-millimeter Telescope (SMT), as well as complimentary transitions taken with the ARO 12-meter. The non-LTE radiative transfer code ESCAPADE has been used to obtain the molecular abundances and distributions in VY CMa, including modeling of the various asymmetric outflow geometries in this source. For example, SO and SO2 were determined to arise from five distinct outflows, four of which are asymmetric with respect to the central star. Abundances of these two sulfur-bearing molecules range from 3 x 10-8 - 2.5 x 10-7 for the various outflows. Similar results will be presented for molecules like CS, SiS, HCN, and SiO, as well as more exotic species like NS, PO, AlO, and AlOH. The molecular abundances between the various outflows will be compared and implications for supergiant chemistry will be discussed.

  20. A global database of ant species abundances

    Czech Academy of Sciences Publication Activity Database

    Gibb, H.; Dunn, R. R.; Sanders, N. J.; Grossman, B. F.; Photakis, M.; Abril, S.; Agosti, D.; Andersen, A. N.; Angulo, E.; Armbrecht, I.; Arnan, X.; Baccaro, F. B.; Bishop, T. R.; Boulay, R.; Brühl, C.; Castracani, C.; Cerdá, X.; Del Toro, I.; Delsinne, T.; Diaz, M.; Donoso, D. A.; Ellison, A. M.; Enríquez, M. L.; Fayle, Tom Maurice; Feener, D. H.; Fisher, B. L.; Fisher, R. N.; Fitzpatrick, M. C.; Gómez, C.; Gotelli, N. J.; Gove, A.; Grasso, D. A.; Groc, S.; Guenard, B.; Gunawardene, N.; Heterick, B.; Hoffmann, B.; Janda, Milan; Jenkins, C.; Kaspari, M.; Klimeš, Petr; Lach, L.; Laeger, T.; Lattke, J.; Leponce, M.; Lessard, J.-P.; Longino, J.; Lucky, A.; Luke, S. H.; Majer, J.; McGlynn, T. P.; Menke, S.; Mezger, D.; Mori, A.; Moses, Jimmy; Munyai, T. C.; Pacheco, R.; Paknia, O.; Pearce-Duvet, J.; Pfeiffer, M.; Philpott, S. M.; Resasco, J.; Retana, J.; Silva, R. R.; Sorger, M. D.; Souza, J.; Suarez, A.; Tista, M.; Vasconcelos, H. L.; Vonshak, M.; Weisser, M. D.; Yates, M.; Parr, C. L.

    2017-01-01

    Roč. 98, č. 3 (2017), s. 883-884 ISSN 0012-9658 R&D Projects: GA ČR GB14-36098G; GA ČR GAP505/12/2467; GA ČR GPP505/12/P875 Institutional support: RVO:60077344 Keywords : abundance * ants * database Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.809, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/ecy.1682/abstract

  1. Why abundant tropical tree species are phylogenetically old.

    Science.gov (United States)

    Wang, Shaopeng; Chen, Anping; Fang, Jingyun; Pacala, Stephen W

    2013-10-01

    Neutral models of species diversity predict patterns of abundance for communities in which all individuals are ecologically equivalent. These models were originally developed for Panamanian trees and successfully reproduce observed distributions of abundance. Neutral models also make macroevolutionary predictions that have rarely been evaluated or tested. Here we show that neutral models predict a humped or flat relationship between species age and population size. In contrast, ages and abundances of tree species in the Panamanian Canal watershed are found to be positively correlated, which falsifies the models. Speciation rates vary among phylogenetic lineages and are partially heritable from mother to daughter species. Variable speciation rates in an otherwise neutral model lead to a demographic advantage for species with low speciation rate. This demographic advantage results in a positive correlation between species age and abundance, as found in the Panamanian tropical forest community.

  2. Predictors of leafhopper abundance and richness in a coffee agroecosystem in Chiapas, Mexico.

    Science.gov (United States)

    Burdine, Justin D; Domínguez Martínez, Gabriel H; Philpott, Stacy M

    2014-04-01

    Coffee agroecosystems with a vegetatively complex shade canopy contain high levels of biodiversity. However, as coffee management is intensified, diversity may be lost. Most biodiversity studies in coffee agroecosystems have examined predators and not herbivores, despite their importance as potential coffee pests and coffee disease vectors. We sampled one abundant herbivore group of leafhoppers on an organic coffee farm in Chiapas, Mexico. We sampled leafhoppers with elevated pan traps in high- and moderate-shade coffee during the dry and wet seasons of 2011. The two major objectives were to 1) compare leafhopper abundance and richness during the wet and dry seasons and 2) examine the correlations between habitat characteristics (e.g., vegetation, elevation, and presence of aggressive ants) and leafhopper richness and abundance. We collected 2,351 leafhoppers, representing eight tribes and 64 morphospecies. Leafhopper abundance was higher in the dry season than in the wet season. Likewise, leafhopper richness was higher in the dry season. Several vegetation and other habitat characteristics correlated with abundance and richness of leafhoppers. The number of Inga trees positively correlated with leafhopper abundance, and other significant correlates of abundance included vegetation complexity. Leafhopper richness was correlated with the number of Inga trees. As leafhoppers transmit important coffee diseases, understanding the specific habitat factors correlating with changes in abundance and richness may help predict future disease outbreaks.

  3. Responses of predatory invertebrates to seeding density and plant species richness in experimental tallgrass prairie restorations

    Science.gov (United States)

    Nemec, Kristine T.; Allen, Craig R.; Danielson, Stephen D.; Helzer, Christopher J.

    2014-01-01

    In recent decades, agricultural producers and non-governmental organizations have restored thousands of hectares of former cropland in the central United States with native grasses and forbs. However, the ability of these grassland restorations to attract predatory invertebrates has not been well documented, even though predators provide an important ecosystem service to agricultural producers by naturally regulating herbivores. This study assessed the effects of plant richness and seeding density on the richness and abundance of surface-dwelling (ants, ground beetles, and spiders) and aboveground (ladybird beetles) predatory invertebrates. In the spring of 2006, twenty-four 55 m × 55 m-plots were planted to six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Natural Resources Conservation Service Conservation Reserve Program mix, CP25), at low and high seeding densities. Ants, ground beetles, and spiders were sampled using pitfall traps and ladybird beetles were sampled using sweep netting in 2007–2009. The abundance of ants, ground beetles, and spiders showed no response to seed mix richness or seeding density but there was a significant positive effect of richness on ladybird beetle abundance. Seeding density had a significant positive effect on ground beetle and spider species richness and Shannon–Weaver diversity. These results may be related to differences in the plant species composition and relative amount of grass basal cover among the treatments rather than richness.

  4. Species richness inside and outside long-term exclosures

    Science.gov (United States)

    W. A. Laycock; D. L. Bartos; K. D. Klement

    2004-01-01

    Recent environmental literature contains claims that livestock grazing has caused reduction in species diversity on Western rangelands. Data of species richness (number of species) is presented from inside and outside 24 long-term exclosures in Montana, Utah, and Wyoming. For the average of all exclosures there was no difference between species richness inside and...

  5. Species Richness and Phenology of Cerambycid Beetles in Urban Forest Fragments of Northern Delaware

    Science.gov (United States)

    K. Handley; J. Hough-Goldstein; L.M. Hanks; J.G. Millar; V. D' amico

    2015-01-01

    Cerambycid beetles are abundant and diverse in forests, but much about their host relationships and adult behavior remains unknown. Generic blends of synthetic pheromones were used as lures in traps, to assess the species richness, and phenology of cerambycids in forest fragments in northern Delaware. More than 15,000 cerambycid beetles of 69 species were trapped over...

  6. Distribution and abundance of diatom species from coastal waters of Karachi, Pakistan

    International Nuclear Information System (INIS)

    Khokhar, F. N.; Burhan, Z.; Iqbal, P.; Abbasi, J.; Siddiqui, P.

    2016-01-01

    This is the first comprehensive study on the distribution and abundance of diatom species from the coastal and nearshore waters of Karachi, Pakistan, bordering northern Arabian Sea. A total of 20 genera are recorded in high abundance (Cerataulina, Chaetoceros, Coscinodiscus, Cylindrotheca, Eucampia, Guinardia, Haslea, Hemiaulus, Lauderia, Lennoxia, Leptocylindrus, Navicula, Nitzschia, Trieres, Planktoniella, Pleurosigma, Pseudo-nitzschia, Rhizosolenia, Thalassionema and Thalassiosira). The most abundant genera were observed Guinardia, Chaetoceros, Leptocylindrus, Nitzschia and Lennoxia at all stations. Manora coastal station (MI-1) had high abundance corresponding with high Chlorophyll a (130 meu gL- l) values. Minimum abundance and low chlorophyll a value (0.05μgL-l) were observed at Mubarak Village coastal station (MV-1). Diatom abundance showed significant correlation with Chlorophyll a. In present study 12 centric and 8 pennate forms were recorded and similarly high diversity of centric taxa was observed compared to pennate forms. A total of 134 species are recorded of which 40 species were observed at four stations, 31species at three stations, 23 at two stations and 40 species only at one station. The total phytoplankton and diatom peak abundance was observed during NE monsoon (winter season) associated with nutrient loading through up-sloping of nutrient rich water upwelled off of Oman during South West monsoon. Overall higher diversity was observed at Manora coastal and nearshore stations (MI-1, MI-2) indicating the influence of organic pollution loading from Layari and Malir rivers. (author)

  7. Abundance of introduced species at home predicts abundance away in herbaceous communities

    Science.gov (United States)

    J. Firn; J.L. Moore; A.S. MacDougall; E.T. Borer; E.W. Seabloom; J. HilleRisLambers; S. Harpole; E.E. Cleland; C.S. Brown; J.M.H. Knops; S.M. Prober; D.A. Pyke; K.A. Farrell; J.D. Bakker; L.R. O’Halloran; P.B. Adler; S.L. Collins; C.M. D’Antonio; M.J. Crawley; E.M. Wolkovich; K.J. La Pierre; B.A. Melbourne; Y. Hautier; J.W. Morgan; A.D.B. Leakey; A.D. Kay; R.L. McCulley; K.F. Davies; C.J. Stevens; C.J. Chu

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at...

  8. Geographic range size and determinants of avian species richness

    DEFF Research Database (Denmark)

    Jetz, Walter; Rahbek, Carsten

    2002-01-01

    Geographic patterns in species richness are mainly based on wide-ranging species because their larger number of distribution records has a disproportionate contribution to the species richness counts. Here we demonstrate how this effect strongly influences our understanding of what determines spe...

  9. Abundance, distribution and species composition of fish larvae in ...

    African Journals Online (AJOL)

    improving our knowledge of the abundance, distribution and species diversity ... banks as well as in the mid-channel, thus eliminating any bias that might have .... cond method (Table 2) may bias the importance of a single species due to one, ...

  10. Dispersal ability determines the scaling properties of species abundance distributions

    DEFF Research Database (Denmark)

    Borda-De-Água, Luís; Whittaker, Robert James; Cardoso, Pedro

    2017-01-01

    with computer simulations, low dispersal ability species generate a hump for intermediate abundance classes earlier than the distributions of high dispersal ability species. Importantly, when plotted as function of sample size, the raw moments of the SADs of arthropods have a power law pattern similar...

  11. Human land use promotes the abundance and diversity of exotic species on caribbean islands.

    Science.gov (United States)

    Jesse, Wendy A M; Behm, Jocelyn E; Helmus, Matthew R; Ellers, Jacintha

    2018-05-31

    Human land use causes major changes in species abundance and composition, yet native and exotic species can exhibit different responses to land use change. Native populations generally decline in human-impacted habitats while exotic species often benefit. In this study, we assessed the effects of human land use on exotic and native reptile diversity, including functional diversity, which relates to the range of habitat use strategies in biotic communities. We surveyed 114 reptile communities from localities that varied in habitat structure and human impact level on two Caribbean islands, and calculated species richness, overall abundance and evenness for every plot. Functional diversity indices were calculated using published trait data, which enabled us to detect signs of trait filtering associated with impacted habitats. Our results show that environmental variation among sampling plots was explained by two PCA ordination axes related to habitat structure (i.e. forest or non-forest) and human impact level (i.e. addition of man-made constructions such as roads and buildings). Several diversity indices were significantly correlated with the two PCA axes, but exotic and native species showed opposing responses. Native species reached the highest abundance in forests, while exotic species were absent in this habitat. Human impact was associated with an increase in exotic abundance and species richness, while native species showed no significant associations. Functional diversity was highest in non-forested environments on both islands, and further increased on St. Martin with the establishment of functionally unique exotic species in non-forested habitat. Habitat structure, rather than human impact, proved to be an important agent for environmental filtering of traits, causing divergent functional trait values across forested and non-forested environments. Our results illustrate the importance of considering various elements of land use when studying its impact on

  12. Differences in species richness patterns between unicellular and multicellular organisms.

    Science.gov (United States)

    Hillebrand, Helmut; Watermann, Frank; Karez, Rolf; Berninger, Ulrike-G

    2001-01-01

    For unicellular organisms, a lack of effects of local species richness on ecosystem function has been proposed due to their locally high species richness and their ubiquitous distribution. High dispersal ability and high individual numbers may enable unicellular taxa to occur everywhere. Using our own and published data sets on uni- and multicellular organisms, we conducted thorough statistical analyses to test whether (1) unicellular taxa show higher relative local species richness compared to multicellular taxa, (2) unicellular taxa show lower slopes of the species:area relationships and species:individuals relationships, and (3) the species composition of unicellular taxa is less influenced by geographic distance compared to multicellular taxa. We found higher local species richness compared to the global species pool for unicellular organisms than for metazoan taxa. The difference was significant if global species richness was conservatively estimated but not if extrapolated, and therefore higher richness estimates were used. Both microalgae and protozoans showed lower slopes between species richness and sample size (area or individuals) compared to macrozoobenthos, also indicating higher local species richness for unicellular taxa. The similarity of species composition of both benthic diatoms and ciliates decreased with increasing geographic distance. This indicated restricted dispersal ability of protists and the absence of ubiquity. However, a steeper slope between similarity and distance was found for polychaetes and corals, suggesting a stronger effect of distance on the dispersal of metazoans compared to unicellular taxa. In conclusion, we found partly different species richness patterns among uni- and multicellular eukaryotes, but no strict ubiquity of unicellular taxa. Therefore, the effect of local unicellular species richness on ecosystem function has to be reanalyzed. Macroecological patterns suggested for multicellular organisms may differ in

  13. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    Directory of Open Access Journals (Sweden)

    Katherine A Dafforn

    Full Text Available Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching. Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  14. SPECIES RICHNESS AND UNIFORMITY CONTRIBUTIONS TO BIRD DIVERSITY IN SHADE COFFEE PLANTATIONS IN THE SOUTHEAST OF MEXICO

    Directory of Open Access Journals (Sweden)

    Marco Antonio Altamirano González Ortega

    2012-12-01

    Full Text Available This study examines the contribution of the richness and uniformity in the diversity of birds, and their relationship with covariates of vegetation in a coffee landscape in southern Mexico. Species richness and abundance was recorded in 2010 and 2011 in evergreen forests and three different types of coffee production systems. Changes in the values of species richness and uniformity were detected by a SHE analysis (S = species richness, H = diversity and E = evenness. True diversity (the actual number of species actually represent the diversity of species in the samples was also estimated. The tree cover, shrub cover and tree height were covariates of vegetation that explained the variation in species richness and abundance. SHE analysis indicated that cumulative values of bird diversity increased in all plots with species richness, while the values of uniformity of species decreased. This condition changed with management activities of coffee and / or the arrival of migratory birds. The true diversity, when all species had a weight proportional to its abundance (q = 1, was higher in all plots when they were given greater weight to the dominant species (q = 2. Management practices of tree cover and shrubs and bird migration could explain changes in species richness and uniformity during the agricultural cycle.

  15. Patterns of coral species richness and reef connectivity in Malaysia

    NARCIS (Netherlands)

    Waheed, Z.

    2016-01-01

    Much remains to be discovered about the biodiversity of coral reefs in Malaysia, making this area a priority for coral reef research. This thesis aims to provide insights into the patterns of reef coral species richness and the degree of reef connectivity across Malaysia. For the species richness

  16. Butterfly species richness and diversity in the Trishna Wildlife Sanctuary in South Asia.

    Science.gov (United States)

    Majumder, Joydeb; Lodh, Rahul; Agarwala, B K

    2013-01-01

    Several wildlife sanctuaries in the world are home to the surviving populations of many endemic species. Trishna wildlife sanctuary in northeast India is protected by law, and is home to the last surviving populations of Asian bison (Bos gorus Smith), spectacle monkey (Trachypithecus phayrie Blyth), capped langur (Trachypithecus pileatus Blyth), slow loris (Nycticebus coucang Boddaert), wild cat (Felis chaus Schreber), and wild boars (Sus scrofa L.), among many other animals and plants. The sanctuary was explored for species richness and diversity of butterflies. A six-month-long study revealed the occurrence of 59 butterfly species that included 21 unique species and 9 species listed in the threatened category. The mixed moist deciduous mature forest of the sanctuary harbored greater species richness and species diversity (39 species under 31 genera) than other parts of the sanctuary, which is comprised of regenerated secondary mixed deciduous forest (37 species under 32 genera), degraded forests (32 species under 28 genera), and open grassland with patches of plantations and artificial lakes (24 species under 17 genera). The majority of these species showed a distribution range throughout the Indo-Malayan region and Australasia tropics, and eight species were distributed in the eastern parts of South Asia, including one species, Labadea martha (F.), which is distributed in the eastern Himalayas alone. Estimator Chao 2 provided the best-predicted value of species richness. The steep slope of the species accumulation curve suggested the occurrence of a large number of rare species, and a prolonged gentle slope suggested a higher species richness at a higher sample abundance. The species composition of vegetation-rich habitats showed high similarity in comparison to vegetation-poor habitats.

  17. Fish species composition, diversity and abundance of the lower New ...

    African Journals Online (AJOL)

    A thirteen-week investigation to determine the fish species composition, diversity and abundance of the Lower New Calabar River, in Rivers State, aimed at providing information on the fish stock and their status for documentation, knowledge improvement, and development of conservation and management strategies was ...

  18. Relative abundance of mosquito species in Katsina Metropolis ...

    African Journals Online (AJOL)

    A study was conducted on the relative abundance of mosquito species, around selected areas of Katsina metropolis, Katsina State, Nigeria during the months of January, February, April and June 2010. Mosquitoes were collected from five sampling sites: Kofar Durbi, Kofar Kaura, Kofar Marusa, GRA and Layout. These were ...

  19. The distribution, composition and abundance of fish species in two ...

    African Journals Online (AJOL)

    Fish composition and abundance of two Gold mine reservoir were investigated between May, 2008 and May, 2009. Seven fish families comprising of twelve species of fish were caught during the period of study. The families of fish caught included Anabantidae, Channidae, Clariidae, Cichlidae, Melanopluridae, Mormyridae ...

  20. Fish species composition and abundance on a subtropical, artificial ...

    African Journals Online (AJOL)

    The composition and abundance of fish species on a derelict rocky pier on the Durban beachfront, KwaZulu-. Natal, South Africa, were assessed by means of underwater visual census, using transects. A total of 74 spe- cies were recorded on the reef, with convict surgeons (Acanthurus triostegus), sash damsels ...

  1. Species Composition, Relative Abundance and Distribution of the ...

    African Journals Online (AJOL)

    Species Composition, Relative Abundance and Distribution of the Avian Fauna of Entoto Natural Park and Escarpment, Addis Ababa. ... Eucalyptus plantation, soil erosion, deforestation, habitat fragmentation, settlement and land degradation were the main threats for the distribution of birds in the present study area.

  2. Measuring β-diversity with species abundance data.

    Science.gov (United States)

    Barwell, Louise J; Isaac, Nick J B; Kunin, William E

    2015-07-01

    In 2003, 24 presence-absence β-diversity metrics were reviewed and a number of trade-offs and redundancies identified. We present a parallel investigation into the performance of abundance-based metrics of β-diversity. β-diversity is a multi-faceted concept, central to spatial ecology. There are multiple metrics available to quantify it: the choice of metric is an important decision. We test 16 conceptual properties and two sampling properties of a β-diversity metric: metrics should be 1) independent of α-diversity and 2) cumulative along a gradient of species turnover. Similarity should be 3) probabilistic when assemblages are independently and identically distributed. Metrics should have 4) a minimum of zero and increase monotonically with the degree of 5) species turnover, 6) decoupling of species ranks and 7) evenness differences. However, complete species turnover should always generate greater values of β than extreme 8) rank shifts or 9) evenness differences. Metrics should 10) have a fixed upper limit, 11) symmetry (βA,B  = βB,A ), 12) double-zero asymmetry for double absences and double presences and 13) not decrease in a series of nested assemblages. Additionally, metrics should be independent of 14) species replication 15) the units of abundance and 16) differences in total abundance between sampling units. When samples are used to infer β-diversity, metrics should be 1) independent of sample sizes and 2) independent of unequal sample sizes. We test 29 metrics for these properties and five 'personality' properties. Thirteen metrics were outperformed or equalled across all conceptual and sampling properties. Differences in sensitivity to species' abundance lead to a performance trade-off between sample size bias and the ability to detect turnover among rare species. In general, abundance-based metrics are substantially less biased in the face of undersampling, although the presence-absence metric, βsim , performed well overall. Only

  3. An improved nonparametric lower bound of species richness via a modified good-turing frequency formula.

    Science.gov (United States)

    Chiu, Chun-Huo; Wang, Yi-Ting; Walther, Bruno A; Chao, Anne

    2014-09-01

    It is difficult to accurately estimate species richness if there are many almost undetectable species in a hyper-diverse community. Practically, an accurate lower bound for species richness is preferable to an inaccurate point estimator. The traditional nonparametric lower bound developed by Chao (1984, Scandinavian Journal of Statistics 11, 265-270) for individual-based abundance data uses only the information on the rarest species (the numbers of singletons and doubletons) to estimate the number of undetected species in samples. Applying a modified Good-Turing frequency formula, we derive an approximate formula for the first-order bias of this traditional lower bound. The approximate bias is estimated by using additional information (namely, the numbers of tripletons and quadrupletons). This approximate bias can be corrected, and an improved lower bound is thus obtained. The proposed lower bound is nonparametric in the sense that it is universally valid for any species abundance distribution. A similar type of improved lower bound can be derived for incidence data. We test our proposed lower bounds on simulated data sets generated from various species abundance models. Simulation results show that the proposed lower bounds always reduce bias over the traditional lower bounds and improve accuracy (as measured by mean squared error) when the heterogeneity of species abundances is relatively high. We also apply the proposed new lower bounds to real data for illustration and for comparisons with previously developed estimators. © 2014, The International Biometric Society.

  4. Experimentally reducing species abundance indirectly affects food web structure and robustness.

    Science.gov (United States)

    Barbosa, Milton; Fernandes, G Wilson; Lewis, Owen T; Morris, Rebecca J

    2017-03-01

    Studies on the robustness of ecological communities suggest that the loss or reduction in abundance of individual species can lead to secondary and cascading extinctions. However, most such studies have been simulation-based analyses of the effect of primary extinction on food web structure. In a field experiment we tested the direct and indirect effects of reducing the abundance of a common species, focusing on the diverse and self-contained assemblage of arthropods associated with an abundant Brazilian shrub, Baccharis dracunculifolia D.C. (Asteraceae). Over a 5-month period we experimentally reduced the abundance of Baccharopelma dracunculifoliae (Sternorrhyncha: Psyllidae), the commonest galling species associated with B. dracunculifolia, in 15 replicate plots paired with 15 control plots. We investigated direct effects of the manipulation on parasitoids attacking B. dracunculifoliae, as well as indirect effects (mediated via a third species or through the environment) on 10 other galler species and 50 associated parasitoid species. The experimental manipulation significantly increased parasitism on B. dracunculifoliae in the treatment plots, but did not significantly alter either the species richness or abundance of other galler species. Compared to control plots, food webs in manipulated plots had significantly lower values of weighted connectance, interaction evenness and robustness (measured as simulated tolerance to secondary extinction), even when B. dracunculifoliae was excluded from calculations. Parasitoid species were almost entirely specialized to individual galler species, so the observed effects of the manipulation on food web structure could not have propagated via the documented trophic links. Instead, they must have spread either through trophic links not included in the webs (e.g. shared predators) or non-trophically (e.g. through changes in habitat availability). Our results highlight that the inclusion of both trophic and non

  5. Species richness of motile cryptofauna across a gradient of reef framework erosion

    Science.gov (United States)

    Enochs, I. C.; Manzello, D. P.

    2012-09-01

    Coral reef ecosystems contain exceptionally high concentrations of marine biodiversity, potentially encompassing millions of species. Similar to tropical rainforests and their insects, the majority of reef animal species are small and cryptic, living in the cracks and crevices of structural taxa (trees and corals). Although the cryptofauna make up the majority of a reef's metazoan biodiversity, we know little about their basic ecology. We sampled motile cryptofaunal communities from both live corals and dead carbonate reef framework across a gradient of increasing erosion on a reef in Pacific Panamá. A total of 289 Operational Taxonomic Units (OTUs) from six phyla were identified. We used species-accumulation models fitted to individual- and sample-based rarefaction curves, as well as seven nonparametric richness estimators to estimate species richness among the different framework types. All procedures predicted the same trends in species richness across the differing framework types. Estimated species richness was higher in dead framework (261-370 OTUs) than in live coral substrates (112-219 OTUs). Surprisingly, richness increased as framework structure was eroded: coral rubble contained the greatest number of species (227-320 OTUs) and the lowest estimated richness of 47-115 OTUs was found in the zone where the reef framework had the greatest vertical relief. This contradicts the paradigm that abundant live coral indicates the apex of reef diversity.

  6. Estimating species – area relationships by modeling abundance and frequency subject to incomplete sampling

    Science.gov (United States)

    Yamaura, Yuichi; Connor, Edward F.; Royle, Andy; Itoh, Katsuo; Sato, Kiyoshi; Taki, Hisatomo; Mishima, Yoshio

    2016-01-01

    Models and data used to describe species–area relationships confound sampling with ecological process as they fail to acknowledge that estimates of species richness arise due to sampling. This compromises our ability to make ecological inferences from and about species–area relationships. We develop and illustrate hierarchical community models of abundance and frequency to estimate species richness. The models we propose separate sampling from ecological processes by explicitly accounting for the fact that sampled patches are seldom completely covered by sampling plots and that individuals present in the sampling plots are imperfectly detected. We propose a multispecies abundance model in which community assembly is treated as the summation of an ensemble of species-level Poisson processes and estimate patch-level species richness as a derived parameter. We use sampling process models appropriate for specific survey methods. We propose a multispecies frequency model that treats the number of plots in which a species occurs as a binomial process. We illustrate these models using data collected in surveys of early-successional bird species and plants in young forest plantation patches. Results indicate that only mature forest plant species deviated from the constant density hypothesis, but the null model suggested that the deviations were too small to alter the form of species–area relationships. Nevertheless, results from simulations clearly show that the aggregate pattern of individual species density–area relationships and occurrence probability–area relationships can alter the form of species–area relationships. The plant community model estimated that only half of the species present in the regional species pool were encountered during the survey. The modeling framework we propose explicitly accounts for sampling processes so that ecological processes can be examined free of sampling artefacts. Our modeling approach is extensible and could be applied

  7. abundance and species richness of lombric macrofauna in a semi

    African Journals Online (AJOL)

    N. Ababsa

    2017-09-01

    Sep 1, 2017 ... Department of ecology and environment, Faculty of Nature and Life Sciences, Abbes ... at the northeastern extremity of the Aurès massif, on the last chains ... extraction of earthworms; Manual sorting of a soil block, washing, ...

  8. The effects of forest destruction on the abundance, species richness ...

    African Journals Online (AJOL)

    SARAH

    2013-04-25

    Apr 25, 2013 ... compounds found in plants, animals, or microorganisms. ... fragmented and degraded With the exception of sacred forest ... best-known insects that are involved in pollinating flowers. ... The influence of landscape patterns on butterfly ..... history were recorded in the tropical rain forest areas but due to ...

  9. Inferring invasive species abundance using removal data from management actions

    Science.gov (United States)

    Davis, Amy J.; Hooten, Mevin B.; Miller, Ryan S.; Farnsworth, Matthew L.; Lewis, Jesse S.; Moxcey, Michael; Pepin, Kim M.

    2016-01-01

    Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480–19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small (<50) the effective removal rate needed to accurately estimates abundances was considerably higher (0.70). Based on our post-validation method, 78% of our site/time frame estimates were accurate. To use this modeling framework it is important to have multiple removals (more than three) within a time frame during which demographic changes are minimized (i.e., a closed population; ≤3 months for feral swine). Our results show that the probability of accurately estimating abundance from this model improves with increased sampling effort (8+ flight hours across the 3-month window is best) and increased removal rate. Based on the inverse relationship between inaccurate abundances and

  10. Inferring invasive species abundance using removal data from management actions.

    Science.gov (United States)

    Davis, Amy J; Hooten, Mevin B; Miller, Ryan S; Farnsworth, Matthew L; Lewis, Jesse; Moxcey, Michael; Pepin, Kim M

    2016-10-01

    Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480-19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small (removal rate needed to accurately estimates abundances was considerably higher (0.70). Based on our post-validation method, 78% of our site/time frame estimates were accurate. To use this modeling framework it is important to have multiple removals (more than three) within a time frame during which demographic changes are minimized (i.e., a closed population; ≤3 months for feral swine). Our results show that the probability of accurately estimating abundance from this model improves with increased sampling effort (8+ flight hours across the 3-month window is best) and increased removal rate. Based on the inverse relationship between inaccurate abundances and inaccurate removal

  11. The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir

    Directory of Open Access Journals (Sweden)

    HS Santana

    Full Text Available Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season, predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

  12. The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir.

    Science.gov (United States)

    Santana, H S; Silva, L C F; Pereira, C L; Simião-Ferreira, J; Angelini, R

    2015-01-01

    Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS) was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season), predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

  13. Livestock grazing has minimal effect on the species richness and ...

    African Journals Online (AJOL)

    The Succulent Karoo, one of two arid biodiversity hotspots in the world, is known for its high plant species richness, but little is known about the influence of topography and how it mediates the potentially deleterious effects of grazing. Changes in vegetation species composition, cover and species diversity were examined ...

  14. Human population, grasshopper and plant species richness in European countries

    Science.gov (United States)

    Steck, Claude E.; Pautasso, Marco

    2008-11-01

    Surprisingly, several studies over large scales have reported a positive spatial correlation of people and biodiversity. This pattern has important implications for conservation and has been documented for well studied taxa such as plants, amphibians, reptiles, birds and mammals. However, it is unknown whether the pattern applies also to invertebrates other than butterflies and more work is needed to establish whether the species-people relationship is explained by both variables correlating with other environmental factors. We studied whether grasshopper species richness (Orthoptera, suborder Caelifera) is related to human population size in European countries. As expected, the number of Caelifera species increases significantly with increasing human population size. But this is not the case when controlling for country area, latitude and number of plant species. Variations in Caelifera species richness are primarily associated with variations in plant species richness. Caelifera species richness also increases with decreasing mean annual precipitation, Gross Domestic Product per capita (used as an indicator for economic development) and net fertility rate of the human population. Our analysis confirms the hypothesis that the broad-scale human population-biodiversity correlations can be explained by concurrent variations in factors other than human population size such as plant species richness, environmental productivity, or habitat heterogeneity. Nonetheless, more populated countries in Europe still have more Caelifera species than less populated countries and this poses a particular challenge for conservation.

  15. Butterfly Species Richness in Selected West Albertine Rift Forests

    Directory of Open Access Journals (Sweden)

    Patrice Kasangaki

    2012-01-01

    Full Text Available The butterfly species richness of 17 forests located in the western arm of the Albertine Rift in Uganda was compared using cluster analysis and principal components analysis (PCA to assess similarities among the forests. The objective was to compare the butterfly species richness of the forests. A total of 630 butterfly species were collected in 5 main families. The different species fell into 7 ecological groupings with the closed forest group having the most species and the swamp/wetland group with the fewest number of species. Three clusters were obtained. The first cluster had forests characterized by relatively high altitude and low species richness despite the big area in the case of Rwenzori and being close to the supposed Pleistocene refugium. The second cluster had forests far away from the supposed refugium except Kisangi and moderate species richness with small areas, whereas the third cluster had those forests that were more disturbed, high species richness, and low altitudinal levels with big areas.

  16. Geomorphic controls on elevational gradients of species richness.

    Science.gov (United States)

    Bertuzzo, Enrico; Carrara, Francesco; Mari, Lorenzo; Altermatt, Florian; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2016-02-16

    Elevational gradients of biodiversity have been widely investigated, and yet a clear interpretation of the biotic and abiotic factors that determine how species richness varies with elevation is still elusive. In mountainous landscapes, habitats at different elevations are characterized by different areal extent and connectivity properties, key drivers of biodiversity, as predicted by metacommunity theory. However, most previous studies directly correlated species richness to elevational gradients of potential drivers, thus neglecting the interplay between such gradients and the environmental matrix. Here, we investigate the role of geomorphology in shaping patterns of species richness. We develop a spatially explicit zero-sum metacommunity model where species have an elevation-dependent fitness and otherwise neutral traits. Results show that ecological dynamics over complex terrains lead to the null expectation of a hump-shaped elevational gradient of species richness, a pattern widely observed empirically. Local species richness is found to be related to the landscape elevational connectivity, as quantified by a newly proposed metric that applies tools of complex network theory to measure the closeness of a site to others with similar habitat. Our theoretical results suggest clear geomorphic controls on elevational gradients of species richness and support the use of the landscape elevational connectivity as a null model for the analysis of the distribution of biodiversity.

  17. Short-term effects of habitat fragmentation on the abundance and species richness of beetles in experimental alfalfa micro-landscapes Efectos a corto plazo de la fragmentación del hábitat sobre la abundancia y riqueza de especies de coleópteros en micro-paisajes experimentales de alfalfa

    Directory of Open Access Journals (Sweden)

    AUDREY A. GREZ

    2004-09-01

    Full Text Available Habitat loss and fragmentation are considered as the main causes of biodiversity depression. Habitat loss implies a reduction of suitable habitat for organisms, and habitat fragmentation is a change in the spatial configuration of the landscape, with the remaining fragments resulting more or less isolated. Recent theory indicates that the effects of habitat loss are more important than those of habitat fragmentation, however there are few experimental studies evaluating both processes separately. To test the effects of habitat fragmentation per se on the abundance, species richness and diversity of epigeal coleopterans, 15 (30 x 30 m alfalfa micro-landscapes, distributed in three blocks, were created. On twelve of them, 84 % of the habitat was removed, leaving in each landscape four or 16 fragments separated by 2 or 6 m of bare ground. From December 2002 to April 2003, before and after fragmentation, coleopterans were sampled using pitfall traps. In total, 8,074 coleopterans of 75 species belonging to 16 families were captured. Neither habitat fragmentation nor habitat loss affected the total abundance of coleopterans, with the exception of Anthicidae that was more abundant in the micro-landscapes composed by four fragments separated for 2 m. This family was also more abundant in the matrix of fragmented micro-landscapes, while most other beetle families were more abundant in the fragments, significantly Carabidae and Lathridiidae. Species richness (per trap and per landscape was higher in micro-landscapes with 16 fragments separated by 6 m. Contrary to what is described frequently in the literature, habitat fragmentation did not negatively affect the abundance or the species richness of epigeal coleopterans. Rather, smaller and more isolated alfalfa fragments seem to provide habitat to support greater biodiversity. These results agree with more recent findings where habitat fragmentation per se seems not to have deleterious effects on the fauna

  18. Productivity is a poor predictor of plant species richness

    Science.gov (United States)

    P.B. Adler; E.T. Borer; H. Hillebrand; Y. Hautier; A. Hector; S. Harpole; L.R. O’Halloran; J.B. Grace; M. Anderson; J.D. Bakker; L.A. Biederman; C.S. Brown; Y.M. Buckley; L.B. Calabrese; C.-J. Chu; E.E. Cleland; S.L. Collins; K.L. Cottingham; M.J. Crawley; E.I. Damschen; K.W. Davies; N.M. DeCrappeo; P.A. Fay; J. Firn; P. Frater; E.I. Gasarch; D.S. Gruner; N. Hagenah; J. Hille. Ris Lambers

    2011-01-01

    For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent...

  19. Estimating species richness and status of solitary bees and bumblebees in agricultural semi-natural habitats

    DEFF Research Database (Denmark)

    Calabuig, Isabel

    2000-01-01

    Estimation of Western Europe number of bee species varies between 2000 and 4500 (Williams 1995) but there are substantial indications of a decline in bee species in Europe and other regions. In Denmark, wild bee species richness, distribution, and abundance have not been studied in detail for about...... 75 years, and nothing is known about which species are potentially vulnerable or endangered. A rough estimate of solitary bees and bumblebees includes approximately 238 species (26 genera) and 29 species respectively. In a pan-trap survey of six kilometres of semi-natural habitats in a Danish...... agricultural landscape, 72 solitary bee species and 19 species of bumblebees were recorded, several of which are considered vulnerable or endangered in neighbouring countries. Nesting conditions for rare cavity-nesting species and the possible role of the semi-natural habitats as corridors for species...

  20. Should Ecosystem Management Involve Active Control of Species Abundances?

    Directory of Open Access Journals (Sweden)

    Robert B. Lessard

    2005-12-01

    Full Text Available We review four case studies in which there is a risk of extinction or severe reduction in highly valued species if we ignore either, or both, of two ecosystem control options. "Symptomatic control" implies direct control of extinction risk through direct harvesting or culling of competitors and predators. "Systemic control" implies treating the causes of the problem that led to an unnaturally high abundance in the first place. We demonstrate, with a discussion of historically observed population trends, how surprising trophic interactions can emerge as a result of alterations to a system. Simulation models were developed for two of the case studies as aids to adaptive policy design, to expose possible abundance changes caused by trophic interactions and to highlight key uncertainties about possible responses to ecosystem management policies involving active intervention to control abundances. With reasonable parameter values, these models predict a wide range of possible responses given available data, but do indicate a good chance that active control would reverse declines and reverse extinction risks. We find that controlling seal (Phoca vitulina populations in the Georgia Strait increases juvenile survival rates of commercial salmon (Oncorhynchus spp. species, but that commensurate increases in hake populations from decreased seal predation could be a compensatory source of predation on juvenile salmon. We also show that wolf (Canis lupus control and moose (Alces alces harvest bring about a recovery in caribou (Rangifer tarandus caribou populations, where simple habitat protection policies fail to recover caribou before wolf predation causes severe declines. The results help address a common problem in disturbed ecosystems, where controlling extinction risks can mean choosing between active control of species abundance or establishing policies of protection, and allowing threatened species to recover naturally.

  1. Dataset on the regulation of banana weevil abundance and corm damage associated with plant richness and the ground-dwelling arthropods’ food web

    Directory of Open Access Journals (Sweden)

    Charlotte Poeydebat

    2017-12-01

    Full Text Available The data presented in this article are related to the research article entitled ̎Plant richness enhances banana weevil regulation in a tropical agroecosystem by affecting a multitrophic food web ̎ [1]. It provides information about plant species richness, weevil corm damage and the abundance of different arthropod groups, including the banana weevil and its potential natural enemies and alternative preys.

  2. Partitioning sources of variation in vertebrate species richness

    Science.gov (United States)

    Boone, R.B.; Krohn, W.B.

    2000-01-01

    Aim: To explore biogeographic patterns of terrestrial vertebrates in Maine, USA using techniques that would describe local and spatial correlations with the environment. Location: Maine, USA. Methods: We delineated the ranges within Maine (86,156 km2) of 275 species using literature and expert review. Ranges were combined into species richness maps, and compared to geomorphology, climate, and woody plant distributions. Methods were adapted that compared richness of all vertebrate classes to each environmental correlate, rather than assessing a single explanatory theory. We partitioned variation in species richness into components using tree and multiple linear regression. Methods were used that allowed for useful comparisons between tree and linear regression results. For both methods we partitioned variation into broad-scale (spatially autocorrelated) and fine-scale (spatially uncorrelated) explained and unexplained components. By partitioning variance, and using both tree and linear regression in analyses, we explored the degree of variation in species richness for each vertebrate group that Could be explained by the relative contribution of each environmental variable. Results: In tree regression, climate variation explained richness better (92% of mean deviance explained for all species) than woody plant variation (87%) and geomorphology (86%). Reptiles were highly correlated with environmental variation (93%), followed by mammals, amphibians, and birds (each with 84-82% deviance explained). In multiple linear regression, climate was most closely associated with total vertebrate richness (78%), followed by woody plants (67%) and geomorphology (56%). Again, reptiles were closely correlated with the environment (95%), followed by mammals (73%), amphibians (63%) and birds (57%). Main conclusions: Comparing variation explained using tree and multiple linear regression quantified the importance of nonlinear relationships and local interactions between species

  3. Multiscale assessment of patterns of avian species richness

    DEFF Research Database (Denmark)

    Rahbek, C; Graves, G R

    2001-01-01

    at continental scales. We used a database of the geographic ranges of 2,869 species of birds breeding in South America (nearly a third of the world's living avian species) to explore the influence of climate, quadrat area, ecosystem diversity, and topography on species richness gradients at 10 spatial scales...... (quadrat area, approximately 12,300 to approximately 1,225,000 km(2)). Topography, precipitation, topography x latitude, ecosystem diversity, and cloud cover emerged as the most important predictors of regional variability of species richness in regression models incorporating 16 independent variables...... the hypothesis that terrestrial species richness from the equator to the poles is ultimately governed by a synergism between climate and coarse-scale topographic heterogeneity....

  4. Diversification rates and species richness across the Tree of Life.

    Science.gov (United States)

    Scholl, Joshua P; Wiens, John J

    2016-09-14

    Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies. © 2016 The Author(s).

  5. Abundance modelling of invasive and indigenous Culicoides species in Spain

    Directory of Open Access Journals (Sweden)

    Els Ducheyne

    2013-11-01

    Full Text Available In this paper we present a novel methodology applied in Spain to model spatial abundance patterns of potential vectors of disease at a medium spatial resolution of 5 x 5 km using a countrywide database with abundance data for five Culicoides species, random regression Forest modelling and a spatial dataset of ground measured and remotely sensed eco-climatic and environmental predictor variables. First the probability of occurrence was computed. In a second step a direct regression between the probability of occurrence and trap abundance was established to verify the linearity of the relationship. Finally the probability of occurrence was used in combination with the set of predictor variables to model abundance. In each case the variable importance of the predictors was used to biologically interpret results and to compare both model outputs, and model performance was assessed using four different accuracy measures. Results are shown for C. imicola, C. newsteadii, C. pulicaris group, C. punctatus and C. obsoletus group. In each case the probability of occurrence is a good predictor of abundance at the used spatial resolution of 5 x 5 km. In addition, the C. imicola and C. obsoletus group are highly driven by summer rainfall. The spatial pattern is inverse between the two species, indicating that the lower and upper thresholds are different. C. pulicaris group is mainly driven by temperature. The patterns for C. newsteadii and C. punctatus are less clear. It is concluded that the proposed methodology can be used as an input to transmission-infection-recovery (TIR models and R0 models. The methodology will become available to the general public as part of the VECMAPTM software.

  6. Richness and Abundance of Lianas with Different Diameter Classes in Permanent Plots in the Amazon in Mato Grosso

    Directory of Open Access Journals (Sweden)

    D. G. Ferraz

    2013-11-01

    Full Text Available Lianas are an important component of the structure and diversity of tropical forests and the Amazon biome is one of few natural protected areas that still support the highest level of biodiversity in the world. Generally in disturbed forests high densities of lianas are found than mature forests. The aim of this study is to investigate the richness among families and lianas abundance with different diameter classes in permanent plots in the Amazon of Mato Grosso. To the survey were placed 8 plots of 40 x 250 in a forest fragment that has been management for 30 years, where we sampled lianas species with diameter breast height (DBH ≥ 1 cm. There were sampled 3970 stems in the permanent plots, and the two most abundant were 2 and 6 with 594 and 573 individuals respectively. The richest families were Sapindaceae, Dilleniaceae, Menispermaceae and Fabaceae. These results confirm the hypothesis that disturbed areas have more density of lianas with small DBH.

  7. Testing the Relationships between Diversification, Species Richness, and Trait Evolution.

    Science.gov (United States)

    Kozak, Kenneth H; Wiens, John J

    2016-11-01

    Understanding which traits drive species diversification is essential for macroevolutionary studies and to understand patterns of species richness among clades. An important tool for testing if traits influence diversification is to estimate rates of net diversification for each clade, and then test for a relationship between traits and diversification rates among clades. However, this general approach has become very controversial. Numerous papers have now stated that it is inappropriate to analyze net diversification rates in groups in which clade richness is not positively correlated with clade age. Similarly, some have stated that variation in net diversification rates does not explain variation in species richness patterns among clades across the Tree of Life. Some authors have also suggested that strong correlations between richness and diversification rates are a statistical artifact and effectively inevitable. If this latter point is true, then correlations between richness and diversification rates would be uninformative (or even misleading) for identifying how much variation in species richness among clades is explained by variation in net diversification rates. Here, we use simulations (based on empirical data for plethodontid salamanders) to address three main questions. First, how is variation in net diversification rates among clades related to the relationship between clade age and species richness? Second, how accurate are these net diversification rate estimators, and does the age-richness relationship have any relevance to their accuracy? Third, is a relationship between species richness and diversification rates an inevitable, statistical artifact? Our simulations show that strong, positive age-richness relationships arise when diversification rates are invariant among clades, whereas realistic variation in diversification rates among clades frequently disrupts this relationship. Thus, a significant age-richness relationship should not be a

  8. Ant species richness of fynbos and forest ecosystems in the ...

    African Journals Online (AJOL)

    The ant fauna in fynbos and forest habitats in the southern Cape are compared. There is no significant difference in ant species richness between the two undisturbed habitat types, and the only two species common to both are Acantholepis capensis and Camponotus maculatus. The degree of Hakea sericea infestation in ...

  9. Multiscale perspectives of species richness in East Africa

    NARCIS (Netherlands)

    Said, M.

    2003-01-01

    This dissertation describes and analyses animal species richness in East Africa from a multi-scale perspective. We studied diversity patterns at sub-continental, national and sub-national level. The study demonstrated that species diversity patterns were scale-dependent. Diversity patterns varied

  10. Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis

    Science.gov (United States)

    Laughlin, D.C.; Abella, S.R.; Covington, W.W.; Grace, J.B.

    2007-01-01

    Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North-central Arizona, USA. Methods: We sampled 75 0.05-ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive effect of richness on plant cover. Richness was strongly related to soil nitrogen in the model, with evidence for both a direct negative effect and an indirect non-linear relationship mediated through understory plant cover. Soil organic matter appeared to have a positive influence on understory richness that was independent of soil nitrogen. Richness was lowest where the forest overstory was densest, which can be explained through indirect effects on soil organic matter, soil nitrogen and understory cover. Finally, model results suggest a variety of direct and indirect processes whereby mineral soil properties can influence richness. Conclusions: Understory plant species richness and plant cover in P. ponderosa forests appear to be significantly influenced by soil organic matter and nitrogen, which are, in turn, related to overstory density and composition and mineral soil properties. Thus, soil properties can impose direct and indirect constraints on local species diversity in ponderosa pine forests. ?? IAVS; Opulus Press.

  11. Evaluating species richness: biased ecological inference results from spatial heterogeneity in species detection probabilities

    Science.gov (United States)

    McNew, Lance B.; Handel, Colleen M.

    2015-01-01

    Accurate estimates of species richness are necessary to test predictions of ecological theory and evaluate biodiversity for conservation purposes. However, species richness is difficult to measure in the field because some species will almost always be overlooked due to their cryptic nature or the observer's failure to perceive their cues. Common measures of species richness that assume consistent observability across species are inviting because they may require only single counts of species at survey sites. Single-visit estimation methods ignore spatial and temporal variation in species detection probabilities related to survey or site conditions that may confound estimates of species richness. We used simulated and empirical data to evaluate the bias and precision of raw species counts, the limiting forms of jackknife and Chao estimators, and multi-species occupancy models when estimating species richness to evaluate whether the choice of estimator can affect inferences about the relationships between environmental conditions and community size under variable detection processes. Four simulated scenarios with realistic and variable detection processes were considered. Results of simulations indicated that (1) raw species counts were always biased low, (2) single-visit jackknife and Chao estimators were significantly biased regardless of detection process, (3) multispecies occupancy models were more precise and generally less biased than the jackknife and Chao estimators, and (4) spatial heterogeneity resulting from the effects of a site covariate on species detection probabilities had significant impacts on the inferred relationships between species richness and a spatially explicit environmental condition. For a real dataset of bird observations in northwestern Alaska, the four estimation methods produced different estimates of local species richness, which severely affected inferences about the effects of shrubs on local avian richness. Overall, our results

  12. Sexual selection predicts species richness across the animal kingdom.

    Science.gov (United States)

    Janicke, Tim; Ritchie, Michael G; Morrow, Edward H; Marie-Orleach, Lucas

    2018-05-16

    Our improving knowledge of the animal tree of life consistently demonstrates that some taxa diversify more rapidly than others, but what contributes to this variation remains poorly understood. An influential hypothesis proposes that selection arising from competition for mating partners plays a key role in promoting speciation. However, empirical evidence showing a link between proxies of this sexual selection and species richness is equivocal. Here, we collected standardized metrics of sexual selection for a broad range of animal taxa, and found that taxonomic families characterized by stronger sexual selection on males show relatively higher species richness. Thus, our data support the hypothesis that sexual selection elevates species richness. This could occur either by promoting speciation and/or by protecting species against extinction. © 2018 The Author(s).

  13. Effects of trophic skewing of species richness on ecosystem functioning in a diverse marine community.

    Directory of Open Access Journals (Sweden)

    Pamela L Reynolds

    Full Text Available Widespread overharvesting of top consumers of the world's ecosystems has "skewed" food webs, in terms of biomass and species richness, towards a generally greater domination at lower trophic levels. This skewing is exacerbated in locations where exotic species are predominantly low-trophic level consumers such as benthic macrophytes, detritivores, and filter feeders. However, in some systems where numerous exotic predators have been added, sometimes purposefully as in many freshwater systems, food webs are skewed in the opposite direction toward consumer dominance. Little is known about how such modifications to food web topology, e.g., changes in the ratio of predator to prey species richness, affect ecosystem functioning. We experimentally measured the effects of trophic skew on production in an estuarine food web by manipulating ratios of species richness across three trophic levels in experimental mesocosms. After 24 days, increasing macroalgal richness promoted both plant biomass and grazer abundance, although the positive effect on plant biomass disappeared in the presence of grazers. The strongest trophic cascade on the experimentally stocked macroalgae emerged in communities with a greater ratio of prey to predator richness (bottom-rich food webs, while stronger cascades on the accumulation of naturally colonizing algae (primarily microalgae with some early successional macroalgae that recruited and grew in the mesocosms generally emerged in communities with greater predator to prey richness (the more top-rich food webs. These results suggest that trophic skewing of species richness and overall changes in food web topology can influence marine community structure and food web dynamics in complex ways, emphasizing the need for multitrophic approaches to understand the consequences of marine extinctions and invasions.

  14. Plant species richness sustains higher trophic levels of soil nematode communities after consecutive environmental perturbations.

    Science.gov (United States)

    Cesarz, Simone; Ciobanu, Marcel; Wright, Alexandra J; Ebeling, Anne; Vogel, Anja; Weisser, Wolfgang W; Eisenhauer, Nico

    2017-07-01

    The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.

  15. The challenge of accurately documenting bee species richness in agroecosystems: bee diversity in eastern apple orchards

    Science.gov (United States)

    Russo, Laura; Park, Mia; Gibbs, Jason; Danforth, Bryan

    2015-01-01

    Bees are important pollinators of agricultural crops, and bee diversity has been shown to be closely associated with pollination, a valuable ecosystem service. Higher functional diversity and species richness of bees have been shown to lead to higher crop yield. Bees simultaneously represent a mega-diverse taxon that is extremely challenging to sample thoroughly and an important group to understand because of pollination services. We sampled bees visiting apple blossoms in 28 orchards over 6 years. We used species rarefaction analyses to test for the completeness of sampling and the relationship between species richness and sampling effort, orchard size, and percent agriculture in the surrounding landscape. We performed more than 190 h of sampling, collecting 11,219 specimens representing 104 species. Despite the sampling intensity, we captured wild bees did not appear to be a factor, as we found no correlation between honeybee and wild bee abundance. Our study shows that the pollinator fauna of agroecosystems can be diverse and challenging to thoroughly sample. We demonstrate that there is high temporal variation in community composition and that sites vary widely in the sampling effort required to fully describe their diversity. In order to maximize pollination services provided by wild bee species, we must first accurately estimate species richness. For researchers interested in providing this estimate, we recommend multiyear studies and rarefaction analyses to quantify the gap between observed and expected species richness. PMID:26380684

  16. Likeability of Garden Birds: Importance of Species Knowledge & Richness in Connecting People to Nature.

    Science.gov (United States)

    Cox, Daniel T C; Gaston, Kevin J

    2015-01-01

    Interacting with nature is widely recognised as providing many health and well-being benefits. As people live increasingly urbanised lifestyles, the provision of food for garden birds may create a vital link for connecting people to nature and enabling them to access these benefits. However, it is not clear which factors determine the pleasure that people receive from watching birds at their feeders. These may be dependent on the species that are present, the abundance of individuals and the species richness of birds around the feeders. We quantitatively surveyed urban households from towns in southern England to determine the factors that influence the likeability of 14 common garden bird species, and to assess whether people prefer to see a greater abundance of individuals or increased species richness at their feeders. There was substantial variation in likeability across species, with songbirds being preferred over non-songbirds. Species likeability increased for people who fed birds regularly and who could name the species. We found a strong correlation between the number of species that a person could correctly identify and how connected to nature they felt when they watched garden birds. Species richness was preferred over a greater number of individuals of the same species. Although we do not show causation this study suggests that it is possible to increase the well-being benefits that people gain from watching birds at their feeders. This could be done first through a human to bird approach by encouraging regular interactions between people and their garden birds, such as through learning the species names and providing food. Second, it could be achieved through a bird to human approach by increasing garden songbird diversity because the pleasure that a person receives from watching an individual bird at a feeder is dependent not only on its species but also on the diversity of birds at the feeder.

  17. Species composition and abundance of Brevipalpus spp. on different citrus species in Mexican orchards.

    Science.gov (United States)

    Salinas-Vargas, D; Santillán-Galicia, M T; Valdez-Carrasco, J; Mora-Aguilera, G; Atanacio-Serrano, Y; Romero-Pescador, P

    2013-08-01

    We studied the abundance of Brevipalpus spp. in citrus orchards in the Mexican states of Yucatan, Quintana Roo and Campeche. Mites were collected from 100 trees containing a mixture of citrus species where sweet orange was always the main species. Eight collections were made at each location from February 2010 to February 2011. Mites from the genus Brevipalpus were separated from other mites surveyed and their abundance and relationships with the different citrus species were quantified throughout the collection period. A subsample of 25% of the total Brevipalpus mites collected were identified to species level and the interaction of mite species and citrus species were described. Brevipalpus spp. were present on all collection dates and their relative abundance was similar on all citrus species studies. The smallest number of mites collected was during the rainy season. Brevipalpus phoenicis (Geijskes) and Brevipalpus californicus (Banks) were the only two species present and they were found in all locations except Campeche, where only B. phoenicis was present. Yucatan and Campeche are at greater risk of leprosis virus transmission than Quintana Roo because the main vector, B. phoenicis, was more abundant than B. californicus. The implications of our results for the design of more accurate sampling and control methods for Brevipalpus spp. are discussed.

  18. Environmental heterogeneity–species richness relationships from a global perspective

    Directory of Open Access Journals (Sweden)

    Anke Stein

    2016-01-01

    Full Text Available Spatial environmental heterogeneity (EH is considered one of the most important factors promoting species richness, but no general consent about the EH–richness relationship exists so far. This is because research methods and study settings vary widely, and because non-significant and negative associations have also been reported. My thesis provides a comprehensive review of the different measurements and terminologies of EH used in the literature, and presents strong quantitative evidence of a generally positive relationship between biotic and abiotic EH and species richness of terrestrial plants and animals from landscape to global extents. In a meta-analysis and a subsequent case study comparing multiple EH measures and their association with mammal species richness worldwide, I furthermore reveal that the outcome of EH–richness studies depends strongly on study design, including both the EH measure chosen and spatial scale. My research contributes to a better understanding of the EH–richness relationship, while identifying future research needs.

  19. Global variation in woodpecker species richness shaped by tree availability

    DEFF Research Database (Denmark)

    Ilsoe, Sigrid Kistrup; Kissling, W. Daniel; Fjeldsa, Jon

    2017-01-01

    . Location: Global. Methods: We used spatial and non-spatial regressions to test for relationships between broad-scale woodpecker species richness and predictor variables describing current and deep-time availability of trees, current climate, Quaternary climate change, human impact, topographical...... a negative indirect effect on woodpecker species richness. Main conclusions: Global species richness of woodpeckers is primarily shaped by current tree cover and precipitation, reflecting a strong biotic association between woodpeckers and trees. Human influence can have a negative effect on woodpecker....... As an example, woodpeckers (Picidae) are closely associated with trees and woody habitats because of multiple morphological and ecological specializations. In this study, we test whether this strong biotic association causes woodpecker diversity to be closely linked to tree availability at a global scale...

  20. Plant species richness and ecosystem multifunctionality in global drylands

    Science.gov (United States)

    Maestre, Fernando T.; Quero, Jose L.; Gotelli, Nicholas J.; Escudero, Adrian; Ochoa, Victoria; Delgado-Baquerizo, Manuel; Garcia-Gomez, Miguel; Bowker, Matthew A.; Soliveres, Santiago; Escolar, Cristina; Garcia-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Gozalo, Beatriz; Gallardo, Antonio; Aguilera, Lorgio; Arredondo, Tulio; Blones, Julio; Boeken, Bertrand; Bran, Donaldo; Conceicao, Abel A.; Cabrera, Omar; Chaieb, Mohamed; Derak, Mchich; Eldridge, David J.; Espinosa, Carlos I.; Florentino, Adriana; Gaitan, Juan; Gatica, M. Gabriel; Ghiloufi, Wahida; Gomez-Gonzalez, Susana; Gutie, Julio R.; Hernandez, Rosa M.; Huang, Xuewen; Huber-Sannwald, Elisabeth; Jankju, Mohammad; Miriti, Maria; Monerris, Jorge; Mau, Rebecca L.; Morici, Ernesto; Naseri, Kamal; Ospina, Abelardo; Polo, Vicente; Prina, Anibal; Pucheta, Eduardo; Ramirez-Collantes, David A.; Romao, Roberto; Tighe, Matthew; Torres-Diaz, Cristian; Val, James; Veiga, Jose P.; Wang, Deli; Zaady, Eli

    2012-01-01

    Experiments suggest that biodiversity enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools (multifunctionality). However, the relationship between biodiversity and multifunctionality has never been assessed globally in natural ecosystems. We report here on a global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth's land surface and support over 38% of the human population. Multifunctionality was positively and significantly related to species richness. The best-fitting models accounted for over 55% of the variation in multifunctionality and always included species richness as a predictor variable. Our results suggest that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in drylands.

  1. Fishing elevates variability in the abundance of exploited species.

    Science.gov (United States)

    Hsieh, Chih-Hao; Reiss, Christian S; Hunter, John R; Beddington, John R; May, Robert M; Sugihara, George

    2006-10-19

    The separation of the effects of environmental variability from the impacts of fishing has been elusive, but is essential for sound fisheries management. We distinguish environmental effects from fishing effects by comparing the temporal variability of exploited versus unexploited fish stocks living in the same environments. Using the unique suite of 50-year-long larval fish surveys from the California Cooperative Oceanic Fisheries Investigations we analyse fishing as a treatment effect in a long-term ecological experiment. Here we present evidence from the marine environment that exploited species exhibit higher temporal variability in abundance than unexploited species. This remains true after accounting for life-history effects, abundance, ecological traits and phylogeny. The increased variability of exploited populations is probably caused by fishery-induced truncation of the age structure, which reduces the capacity of populations to buffer environmental events. Therefore, to avoid collapse, fisheries must be managed not only to sustain the total viable biomass but also to prevent the significant truncation of age structure. The double jeopardy of fishing to potentially deplete stock sizes and, more immediately, to amplify the peaks and valleys of population variability, calls for a precautionary management approach.

  2. Analyzing fractal property of species abundance distribution and diversity indexes.

    Science.gov (United States)

    Su, Qiang

    2016-03-07

    Community diversity is usually characterized by numerical indexes; however it indeed depends on the species abundance distribution (SAD). Diversity indexes and SAD are based on the same information but treating as separate themes. Ranking species abundance from largest to smallest, the decreasing pattern can give the information about the SAD. Frontier proposed such SAD might be a fractal structure, and first applied the Zipf-Mandelbrot model to the SAD study. However, this model fails to include the Zipf model, and also fails to ensure an integer rank. In this study, a fractal model of SAD was reconstructed, and tested with 104 community samples from 8 taxonomic groups. The results show that there was a good fit of the presented model. Fractal parameter (p) determines the SAD of a community. The ecological significance of p relates to the "dominance" of a community. The correlation between p and classical diversity indexes show that Shannon index decreases and Simpson index increases as p increases. The main purpose of this paper is not to compare with other SADs models; it simply provides a new interpretation of SAD model construction, and preliminarily integrates diversity indexes and SAD model into a broader perspective of community diversity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. On the statistical mechanics of species abundance distributions.

    Science.gov (United States)

    Bowler, Michael G; Kelly, Colleen K

    2012-09-01

    A central issue in ecology is that of the factors determining the relative abundance of species within a natural community. The proper application of the principles of statistical physics to species abundance distributions (SADs) shows that simple ecological properties could account for the near universal features observed. These properties are (i) a limit on the number of individuals in an ecological guild and (ii) per capita birth and death rates. They underpin the neutral theory of Hubbell (2001), the master equation approach of Volkov et al. (2003, 2005) and the idiosyncratic (extreme niche) theory of Pueyo et al. (2007); they result in an underlying log series SAD, regardless of neutral or niche dynamics. The success of statistical mechanics in this application implies that communities are in dynamic equilibrium and hence that niches must be flexible and that temporal fluctuations on all sorts of scales are likely to be important in community structure. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Effects of habitat structure on the epifaunal community in Mussismilia corals: does coral morphology influence the richness and abundance of associated crustacean fauna?

    Science.gov (United States)

    Nogueira, Marcos M.; Neves, Elizabeth; Johnsson, Rodrigo

    2015-06-01

    Coral habitat structures increase abundance and richness of organisms by providing niches, easy access to resources and refuge from predators. Corals harbor a great variety of animals; the variation in coral species morphology contributes to the heterogeneity and complexity of habitat types. In this report, we studied the richness and abundance of crustaceans (Decapoda, Copepoda, Peracarida and Ostracoda) associated with three species of Mussismilia exhibiting different growth morphologies, in two different coral reefs of the Bahia state (Caramuanas and Boipeba-Moreré, Brazil). Mussismilia hispida is a massive coral; M. braziliensis also has a massive growth pattern, but forms a crevice in the basal area of the corallum; M. harttii has a meandroid pattern. PERMANOVA analysis suggests significant differences in associated fauna richness among Mussismilia species, with higher values for M. harttii, followed by M. braziliensis and later by M. hispida. The same trend was observed for density, except that the comparison of M. braziliensis and M. hispida did not show differences. Redundancy and canonical correspondence analysis indicated that almost all of the crustacean species were more associated with the M. harttii colonies that formed a group clearly separated from colonies of M. braziliensis and M. hispida. We also found that the internal volume of interpolyp space, only present in M. harttii, was the most important factor influencing richness and abundance of all analyzed orders of crustaceans.

  5. Plant species richness enhances nitrogen retention in green roof plots.

    Science.gov (United States)

    Johnson, Catherine; Schweinhart, Shelbye; Buffam, Ishi

    2016-10-01

    Vegetated (green) roofs have become common in many cities and are projected to continue to increase in coverage, but little is known about the ecological properties of these engineered ecosystems. In this study, we tested the biodiversity-ecosystem function hypothesis using commercially available green roof trays as replicated plots with varying levels of plant species richness (0, 1, 3, or 6 common green roof species per plot, using plants with different functional characteristics). We estimated accumulated plant biomass near the peak of the first full growing season (July 2013) and measured runoff volume after nearly every rain event from September 2012 to September 2013 (33 events) and runoff fluxes of inorganic nutrients ammonium, nitrate, and phosphate from a subset of 10 events. We found that (1) total plant biomass increased with increasing species richness, (2) green roof plots were effective at reducing storm runoff, with vegetation increasing water retention more than soil-like substrate alone, but there was no significant effect of plant species identity or richness on runoff volume, (3) green roof substrate was a significant source of phosphate, regardless of presence/absence of plants, and (4) dissolved inorganic nitrogen (DIN = nitrate + ammonium) runoff fluxes were different among plant species and decreased significantly with increasing plant species richness. The variation in N retention was positively related to variation in plant biomass. Notably, the increased biomass and N retention with species richness in this engineered ecosystem are similar to patterns observed in published studies from grasslands and other well-studied ecosystems. We suggest that more diverse plantings on vegetated roofs may enhance the retention capacity for reactive nitrogen. This is of importance for the sustained health of vegetated roof ecosystems, which over time often experience nitrogen limitation, and is also relevant for water quality in receiving waters

  6. Producing diversity: Agroforests Sustain Avian Richness and Abundance in India's Western Ghats

    Directory of Open Access Journals (Sweden)

    Krithi K Karanth

    2016-09-01

    Full Text Available Globally, protected areas have long been the corner stone of biodiversity conservation efforts. In India’s Western Ghats, small and isolated protected areas are embedded in a matrix of multiple land-uses, most of which include agroforests. These agroforests are being increasingly recognized for their supplementary role in conserving wildlife. We examined bird species richness and densities in areca (Areca catechu, coffee (Coffea arabica and Coffea canephora and rubber (Hevea brasiliensis agroforests in the Western Ghats. We developed a priori hypotheses, predicting that bird species richness and guild density would be highest in coffee, followed by areca and rubber agroforests. We carried out 551 point-count surveys involving 386 hours of sampling in 187 agroforests across a 29,634 km2 area of the Ghats. We observed 204 bird species, of which 170 were residents. The average estimated richness per agroforest was higher in coffee (60.5 compared to rubber (45.4 and areca (34.1. We modeled species richness as a function of relevant biogeographic and environmental covariates. The most influential factors were tree cover, tree density and rainfall in all agroforests, but the strength of these effects varied. Coffee supported higher densities in all four habitat and three feeding guilds compared to areca and rubber. We integrated extensive field sampling with modeling that accounted for imperfect detection, while assessing bird richness and densities across multiple agroforest types. We establish that coffee agroforests are substantially richer in birds than rubber and areca, but all three agroforests play an important role in providing subsidiary habitats for birds in the Ghats. Policy decisions and markets must incorporate such biodiversity values and services provided by these agroforests to sustain and facilitate long-term biodiversity conservation.

  7. Changes in plant species richness induce functional shifts in soil nematode communities in experimental grassland.

    Directory of Open Access Journals (Sweden)

    Nico Eisenhauer

    Full Text Available Changes in plant diversity may induce distinct changes in soil food web structure and accompanying soil feedbacks to plants. However, knowledge of the long-term consequences of plant community simplification for soil animal food webs and functioning is scarce. Nematodes, the most abundant and diverse soil Metazoa, represent the complexity of soil food webs as they comprise all major trophic groups and allow calculation of a number of functional indices.We studied the functional composition of nematode communities three and five years after establishment of a grassland plant diversity experiment (Jena Experiment. In response to plant community simplification common nematode species disappeared and pronounced functional shifts in community structure occurred. The relevance of the fungal energy channel was higher in spring 2007 than in autumn 2005, particularly in species-rich plant assemblages. This resulted in a significant positive relationship between plant species richness and the ratio of fungal-to-bacterial feeders. Moreover, the density of predators increased significantly with plant diversity after five years, pointing to increased soil food web complexity in species-rich plant assemblages. Remarkably, in complex plant communities the nematode community shifted in favour of microbivores and predators, thereby reducing the relative abundance of plant feeders after five years.The results suggest that species-poor plant assemblages may suffer from nematode communities detrimental to plants, whereas species-rich plant assemblages support a higher proportion of microbivorous nematodes stimulating nutrient cycling and hence plant performance; i.e. effects of nematodes on plants may switch from negative to positive. Overall, food web complexity is likely to decrease in response to plant community simplification and results of this study suggest that this results mainly from the loss of common species which likely alter plant-nematode interactions.

  8. Patterns of species richness in sandy beaches of South America ...

    African Journals Online (AJOL)

    The middle shore is primarily occupied by cirolanids and bivalves, and hippid crabs, bivalves and amphipods dominate the lower beach. Generally, species richness increases from upper to lower beach levels. Studies carried out on exposed sandy beaches of south-central Chile (ca. 40°S) show that different beach states ...

  9. Relationships between Plant Biomass and Species Richness under ...

    African Journals Online (AJOL)

    The study was conducted in a montane grassland of Kokosa District, West Arsi Zone of Oromia Region, southern Ethiopia. The objective of the study was to investigate the relationships between aboveground plant biomass and species richness in three farming systems and four grazing management systems. A total of 180 ...

  10. Plant species richness regulates soil respiration through changes in productivity.

    NARCIS (Netherlands)

    Tavares Correa Dias, A.; van Ruijven, J.; Berendse, F.

    2010-01-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

  11. Plant species richness regulates soil respiration through changes in productivity

    NARCIS (Netherlands)

    Dias, A.A.; Ruijven, van J.; Berendse, F.

    2010-01-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

  12. Bird Richness and Abundance in Response to Urban Form in a Latin American City: Valdivia, Chile as a Case Study

    Science.gov (United States)

    García, Cristóbal E.; Estay, Sergio A.

    2015-01-01

    There is mounting evidence that urban areas influence biodiversity. Generalizations however require that multiple urban areas on multiple continents be examined. Here we evaluated the role of urban areas on avian diversity for a South American city, allowing us to examine the effects of urban features common worldwide, using the city of Valdivia, Chile as case study. We assessed the number of birds and their relative abundance in 152 grid cells of equal size (250 m2) distributed across the city. We estimated nine independent variables: land cover diversity (DC), building density (BD), impervious surface (IS),municipal green space (MG),non-municipal green space (NG), domestic garden space (DG), distance to the periphery (DP), social welfare index (SW), and vegetation diversity (RV). Impervious surface represent 41.8% of the study area, while municipal green, non-municipal green and domestic garden represent 11.6%, 23.6% and 16% of the non- man made surface. Exotic vegetation species represent 74.6% of the total species identified across the city. We found 32 bird species, all native with the exception of House Sparrow and Rock Pigeon. The most common species were House Sparrow and Chilean Swallow. Total bird richness responds negatively to IS and MG, while native bird richness responds positively to NG and negatively to BD, IS DG and, RV. Total abundance increase in areas with higher values of DC and BD, and decrease in areas of higher values of IS, SW and VR. Native bird abundance responds positively to NG and negatively to BD, IS MG, DG and RV. Our results suggest that not all the general patterns described in previous studies, conducted mainly in the USA, Europe, and Australia, can be applied to Latin American cities, having important implications for urban planning. Conservation efforts should focus on non-municipal areas, which harbor higher bird diversity, while municipal green areas need to be improved to include elements that can enhance habitat quality for

  13. Bird Richness and Abundance in Response to Urban Form in a Latin American City: Valdivia, Chile as a Case Study.

    Directory of Open Access Journals (Sweden)

    Carmen Paz Silva

    Full Text Available There is mounting evidence that urban areas influence biodiversity. Generalizations however require that multiple urban areas on multiple continents be examined. Here we evaluated the role of urban areas on avian diversity for a South American city, allowing us to examine the effects of urban features common worldwide, using the city of Valdivia, Chile as case study. We assessed the number of birds and their relative abundance in 152 grid cells of equal size (250 m2 distributed across the city. We estimated nine independent variables: land cover diversity (DC, building density (BD, impervious surface (IS,municipal green space (MG,non-municipal green space (NG, domestic garden space (DG, distance to the periphery (DP, social welfare index (SW, and vegetation diversity (RV. Impervious surface represent 41.8% of the study area, while municipal green, non-municipal green and domestic garden represent 11.6%, 23.6% and 16% of the non- man made surface. Exotic vegetation species represent 74.6% of the total species identified across the city. We found 32 bird species, all native with the exception of House Sparrow and Rock Pigeon. The most common species were House Sparrow and Chilean Swallow. Total bird richness responds negatively to IS and MG, while native bird richness responds positively to NG and negatively to BD, IS DG and, RV. Total abundance increase in areas with higher values of DC and BD, and decrease in areas of higher values of IS, SW and VR. Native bird abundance responds positively to NG and negatively to BD, IS MG, DG and RV. Our results suggest that not all the general patterns described in previous studies, conducted mainly in the USA, Europe, and Australia, can be applied to Latin American cities, having important implications for urban planning. Conservation efforts should focus on non-municipal areas, which harbor higher bird diversity, while municipal green areas need to be improved to include elements that can enhance habitat

  14. Bird Richness and Abundance in Response to Urban Form in a Latin American City: Valdivia, Chile as a Case Study.

    Science.gov (United States)

    Silva, Carmen Paz; García, Cristóbal E; Estay, Sergio A; Barbosa, Olga

    2015-01-01

    There is mounting evidence that urban areas influence biodiversity. Generalizations however require that multiple urban areas on multiple continents be examined. Here we evaluated the role of urban areas on avian diversity for a South American city, allowing us to examine the effects of urban features common worldwide, using the city of Valdivia, Chile as case study. We assessed the number of birds and their relative abundance in 152 grid cells of equal size (250 m2) distributed across the city. We estimated nine independent variables: land cover diversity (DC), building density (BD), impervious surface (IS),municipal green space (MG),non-municipal green space (NG), domestic garden space (DG), distance to the periphery (DP), social welfare index (SW), and vegetation diversity (RV). Impervious surface represent 41.8% of the study area, while municipal green, non-municipal green and domestic garden represent 11.6%, 23.6% and 16% of the non- man made surface. Exotic vegetation species represent 74.6% of the total species identified across the city. We found 32 bird species, all native with the exception of House Sparrow and Rock Pigeon. The most common species were House Sparrow and Chilean Swallow. Total bird richness responds negatively to IS and MG, while native bird richness responds positively to NG and negatively to BD, IS DG and, RV. Total abundance increase in areas with higher values of DC and BD, and decrease in areas of higher values of IS, SW and VR. Native bird abundance responds positively to NG and negatively to BD, IS MG, DG and RV. Our results suggest that not all the general patterns described in previous studies, conducted mainly in the USA, Europe, and Australia, can be applied to Latin American cities, having important implications for urban planning. Conservation efforts should focus on non-municipal areas, which harbor higher bird diversity, while municipal green areas need to be improved to include elements that can enhance habitat quality for

  15. Asymptotic size determines species abundance in the marine size spectrum

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Beyer, Jan

    2006-01-01

    The majority of higher organisms in the marine environment display indeterminate growth; that is, they continue to grow throughout their life, limited by an asymptotic size. We derive the abundance of species as a function of their asymptotic size. The derivation is based on size-spectrum theory......, where population structure is derived from physiology and simple arguments regarding the predator-prey interaction. Using a hypothesis of constant satiation, which states that the average degree of satiation is independent of the size of an organism, the number of individuals with a given size is found...... to be proportional to the weight raised to the power -2.05, independent of the predator/prey size ratio. This is the first time the spectrum exponent has been derived solely on the basis of processes at the individual level. The theory furthermore predicts that the parameters in the von Bertalanffy growth function...

  16. Patterns of species richness and diversity of insects associated with cucurbit fruits in the southern part of Cameroon.

    Science.gov (United States)

    Mokam, Didi Gaëlle; Djiéto-Lordon, Champlain; Bilong Bilong, Charles-Félix

    2014-01-01

    Patterns of species diversity and community structure of insects associated with fruits of domesticated cucurbits were investigated from January 2009 to 2011 in three localities from two agroecological zones in the southern part of Cameroon. Rarefaction curves combined with nonparametric estimators of species richness were used to extrapolate species richness beyond our own data. Sampling efforts of over 92% were reached in each of the three study localities. Data collected revealed a total of 66 insect morphospecies belonging to 37 families and five orders, identified from a set of 57,510 insects. The orders Diptera (especially Tephritidae and Lonchaeidae) and Hymenoptera (mainly Braconidae and Eulophidae) were the most important, in terms of both abundance and species richness on the one hand, and effects on agronomic performance on the other. Values for both the species diversity (Shannon and Simpson) and the species richness indices (Margalef and Berger-Parker) calculated showed that the insect communities were species-rich but dominated, all to a similar extent, by five main species (including four fruit fly species and one parasitoid). Species abundance distributions in these communities ranged from the Zipf-Mandelbrot to Mandelbrot models. The communities are structured as tritrophic networks, including cucurbit fruits, fruit-feeding species (fruit flies) and carnivorous species (parasitoids). Within the guild of the parasitoids, about 30% of species, despite their low abundance, may potentially be of use in biological control of important pests. Our field data contribute in important ways to basic knowledge of biodiversity patterns in agrosystems and constitute baseline data for the planned implementation of biological control in Integrated Pest Management. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  17. Marine diversity: the paradigms in patterns of species richness examined

    Directory of Open Access Journals (Sweden)

    John S. Gray

    2001-12-01

    Full Text Available The two central paradigms of marine diversity are that there is a latitudinal cline of increasing species richness from poles to tropics and that species richness increases with depth to a maximum around 2,000 m and thereafter decreases. However, these paradigms were based on data collected in the late 1950´s and early 1960´s. Here I show that the 1960´s data, are not representative and thus the paradigms need re-examination. New data from coastal areas in the northern hemisphere record species richness as high as the highest recorded in the deep-sea. Whilst this suggests that the cline of increasing diversity from shallow to deep-sea does not exist, however, the database for the deep sea is not sufficient to draw such a conclusion. The basic problem with the data from the 1960s is that samples were taken on ecological scales and yet they are used to answer evolutionary questions. The questions that such data were to answer were why do the tropics have higher species richness than polar regions or why do deep-sea sediments have more species than coastal sediments? Evolutionary questions need data from much larger spatial areas. Recently, data representative of large scales have been collected from coastal areas in the northern hemisphere and show that there is a cline of increasing species richness from the Arctic to the tropics, but there does not yet seem to be a similar cline in the southern hemisphere. A number of hypotheses have been proposed for the observed patterns in biodiversity. In terrestrial ecology the energy-productivity hypothesis has gained wide acceptance as an explanation for the latitudinal gradient. Here I examine this and other hypotheses critically. Finally an analysis of research priorities is made. Assessment is urgently needed of the spatial scales and dynamics of species richness from point samples to assemblages, habitats and landscapes, especially in coastal areas and in the tropics, where the threats to

  18. Plant species richness regulates soil respiration through changes in productivity.

    Science.gov (United States)

    Dias, André Tavares Corrêa; van Ruijven, Jasper; Berendse, Frank

    2010-07-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of diversity on soil respiration. We hypothesized that plant diversity could affect soil respiration in two ways. On the one hand, more diverse plant communities have been shown to promote plant productivity, which could increase soil respiration. On the other hand, the nutrient concentration in the biomass produced has been shown to decrease with diversity, which could counteract the production-induced increase in soil respiration. Our results clearly show that soil respiration increased with species richness. Detailed analysis revealed that this effect was not due to differences in species composition. In general, soil respiration in mixtures was higher than would be expected from the monocultures. Path analysis revealed that species richness predominantly regulates soil respiration through changes in productivity. No evidence supporting the hypothesized negative effect of lower N concentration on soil respiration was found. We conclude that shifts in productivity are the main mechanism by which changes in plant diversity may affect soil respiration.

  19. Daughter Species Abundances in Comet C/2014 Q2 (Lovejoy)

    Science.gov (United States)

    McKay, Adam; Cochran, Anita; Dello Russo, Neil; Kelley, Michael

    2015-11-01

    We present analysis of high spectral resolution optical spectra of C/2014 Q2 (Lovejoy) acquired with the Tull Coude spectrometer on the 2.7-meter Harlan J. Smith Telescope at McDonald Observatory and the ARCES spectrometer mounted on the 3.5-meter Astrophysical Research Consortium Telescope at Apache Point Observatory. Both Tull Coude and ARCES provide high spectral resolution (R=30,000-60,000) and a large spectral range of approximately 3500-10000 Angstroms. We obtained two observation epochs, one in February 2015 at a heliocentric distance of 1.3 AU, and another in May 2015 at a heliocentric distance of 1.9 AU. Another epoch in late August 2015 at a heliocentric distance of 3.0 AU is scheduled. We will present production rates of the daughter species CN, C3, CH, C2, and NH2. We will also present H2O production rates derived from the [OI]6300 emission, as well as measurements of the flux ratio of the [OI]5577 Angstrom line to the sum of the [OI]6300 and [OI]6364 Angstrom lines (sometimes referred to as the oxygen line ratio). This ratio is indicative of the CO2 abundance of the comet. As we have observations at several heliocentric distances, we will examine how production rates and mixing ratios of the various species change with heliocentric distance. We will compare our oxygen line measurements to observations of CO2 made with Spitzer, as well as our other daughter species observations to those of candidate parent molecules made at IR wavelengths.

  20. Grassland invader responses to realistic changes in native species richness.

    Science.gov (United States)

    Rinella, Matthew J; Pokorny, Monica L; Rekaya, Romdhane

    2007-09-01

    The importance of species richness for repelling exotic plant invasions varies from ecosystem to ecosystem. Thus, in order to prioritize conservation objectives, it is critical to identify those ecosystems where decreasing richness will most greatly magnify invasion risks. Our goal was to determine if invasion risks greatly increase in response to common reductions in grassland species richness. We imposed treatments that mimic management-induced reductions in grassland species richness (i.e., removal of shallow- and/or deep-rooted forbs and/or grasses and/or cryptogam layers). Then we introduced and monitored the performance of a notorious invasive species (i.e., Centaurea maculosa). We found that, on a per-gram-of-biomass basis, each resident plant group similarly suppressed invader growth. Hence, with respect to preventing C. maculosa invasions, maintaining overall productivity is probably more important than maintaining the productivity of particular plant groups or species. But at the sites we studied, all plant groups may be needed to maintain overall productivity because removing forbs decreased overall productivity in two of three years. Alternatively, removing forbs increased productivity in another year, and this led us to posit that removing forbs may inflate the temporal productivity variance as opposed to greatly affecting time-averaged productivity. In either case, overall productivity responses to single plant group removals were inconsistent and fairly modest, and only when all plant groups were removed did C. maculosa growth increase substantially over a no-removal treatment. As such, it seems that intense disturbances (e.g., prolonged drought, overgrazing) that deplete multiple plant groups may often be a prerequisite for C. maculosa invasion.

  1. NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r-PROCESS-RICH VERY METAL-POOR STARS

    International Nuclear Information System (INIS)

    Sneden, Christopher; Lawler, James E.; Den Hartog, Elizabeth A.; Cowan, John J.; Ivans, Inese I.

    2009-01-01

    We have derived new abundances of the rare earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low-metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally consistent Ba, rare earth, and Hf (56 ≤ Z ≤ 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

  2. Productivity is a poor predictor of plant species richness

    Science.gov (United States)

    Adler, Peter B.; Seabloom, Eric W.; Borer, Elizabeth T.; Hillebrand, Helmut; Hautier, Yann; Hector, Andy; Harpole, W. Stanley; O'Halloran, Lydia R.; Grace, James B.; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori A.; Brown, Cynthia S.; Buckley, Yvonne M.; Calabrese, Laura B.; Chu, Cheng-Jin; Cleland, Elsa E.; Collins, Scott L.; Cottingham, Kathryn L.; Crawley, Michael J.; Damschen, Ellen Ingman; Davies, Kendi F.; DeCrappeo, Nicole M.; Fay, Philip A.; Firn, Jennifer; Frater, Paul; Gasarch, Eve I.; Gruner, Daneil S.; Hagenah, Nicole; Lambers, Janneke Hille Ris; Humphries, Hope; Jin, Virginia L.; Kay, Adam D.; Kirkman, Kevin P.; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Lambrinos, John G.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Morgan, John W.; Mortensen, Brent; Orrock, John L.; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Wang, Gang; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

    2011-01-01

    For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters-2) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity an

  3. Mollusca from a species-rich deep-water Leptometra community in the Alboran Sea

    Directory of Open Access Journals (Sweden)

    Serge Gofas

    2014-12-01

    Full Text Available An exceptional species richness for Mollusca was found on Avempace bank (349-365 m, Djibouti group, Alboran Sea, where the most abundant species was the crinoid Leptometra phalangium. A sample of sediment sieved on a 0.5-mm mesh yielded 156 species of molluscs (83 live-taken, 1772 specimens with a high Shannon-Wiener diversity index (H’(log2=3.60. The dominant mollusc was Limopsis aurita and the six most common species accounted for 77% of the specimens. On the other hand, 42 species were represented by only one or two specimens. Two species are described as new, three more are first findings in the Mediterranean and two are first findings in Iberian waters. One-third of the species have not been reported from the neighbouring, well-explored Alboran Island platform. There is a considerable balance between the trophic groups, denoting a stable and structured community. Most of the species have an extensive Atlantic range, and most have a planktonic larval stage. Therefore, it can be hypothesized that the fauna benefits from a diverse influx of larvae carried in by the more superficial incoming Atlantic current. Because of its exceptional richness, this type of bathyal community with Leptometra and Limopsis should be considered a high priority for habitat conservation in the Mediterranean deep sea.

  4. Constraints on the Mass–Richness Relation from the Abundance and Weak Lensing of SDSS Clusters

    Science.gov (United States)

    Murata, Ryoma; Nishimichi, Takahiro; Takada, Masahiro; Miyatake, Hironao; Shirasaki, Masato; More, Surhud; Takahashi, Ryuichi; Osato, Ken

    2018-02-01

    We constrain the scaling relation between optical richness (λ) and halo mass (M) for a sample of Sloan Digital Sky Survey (SDSS) red-sequence Matched-filter Probabilistic Percolation (redMaPPer) galaxy clusters within the context of the Planck cosmological model. We use a forward modeling approach where we model the probability distribution of optical richness for a given mass, P({ln}λ | M). To model the abundance and the stacked lensing profiles, we use an emulator specifically built to interpolate the halo mass function and the stacked lensing profile for an arbitrary set of halo mass and redshift, which is calibrated based on a suite of high-resolution N-body simulations. We apply our method to 8312 SDSS redMaPPer clusters with 20 ≤ λ ≤ 100 and 0.10 ≤ z λ ≤ 0.33 and show that the lognormal distribution model for P(λ | M), with four free parameters, well reproduces the measured abundances and lensing profiles simultaneously. The constraints are characterized by the mean relation, (M)=A+B{ln}(M/{M}pivot}), with A={3.207}-0.046+0.044 and B={0.993}-0.055+0.041 (68% CL), where the pivot mass scale M pivot = 3 × 1014 h ‑1 M ⊙, and the scatter {σ }lnλ | M}={σ }0+q{ln}(M/{M}pivot}) with {σ }0={0.456}-0.039+0.047 and q=-{0.169}-0.026+0.035. We find that a large scatter in halo masses is required at the lowest-richness bins (20 ≤ λ ≲ 30) in order to reproduce the measurements. Without such a large scatter, the model prediction for the lensing profiles tends to overestimate the measured amplitudes. This might imply a possible contamination of intrinsically low-richness clusters due to the projection effects. Such a low-mass halo contribution is significantly reduced when applying our method to the sample of 30 ≤ λ ≤ 100.

  5. Species are not most abundant in the centre of their geographic range or climatic niche.

    Science.gov (United States)

    Dallas, Tad; Decker, Robin R; Hastings, Alan

    2017-12-01

    The pervasive idea that species should be most abundant in the centre of their geographic range or centre of their climatic niche is a key assumption in many existing ecological hypotheses and has been declared a general macroecological rule. However, empirical support for decreasing population abundance with increasing distance from geographic range or climatic niche centre (distance-abundance relationships) remains fairly weak. We examine over 1400 bird, mammal, fish and tree species to provide a thorough test of distance-abundance relationships, and their associations with species traits and phylogenetic relationships. We failed to detect consistent distance-abundance relationships, and found no association between distance-abundance slope and species traits or phylogenetic relatedness. Together, our analyses suggest that distance-abundance relationships may be rare, difficult to detect, or are an oversimplification of the complex biogeographical forces that determine species spatial abundance patterns. © 2017 John Wiley & Sons Ltd/CNRS.

  6. Modeling broad-scale patterns of avian species richness across the Midwestern United States with measures of satellite image texture

    Science.gov (United States)

    Patrick D. Culbert; Volker C. Radeloff; Veronique St-Louis; Curtis H. Flather; Chadwick D. Rittenhouse; Thomas P. Albright; Anna M. Pidgeon

    2012-01-01

    Avian biodiversity is threatened, and in order to prioritize limited conservation resources and conduct effective conservation planning a better understanding of avian species richness patterns is needed. The use of image texture measures, as a proxy for the spatial structure of land cover and vegetation, has proven useful in explaining patterns of avian abundance and...

  7. Long-term temporal and spatial changes in the richness and relative abundance of the inshore fish community of the British North Sea Coast

    Science.gov (United States)

    Henderson, Peter A.

    2017-09-01

    Changes in temporal and spatial composition of the British inshore North Sea fish community are reviewed. Sampling from the cooling water filter screens of power stations bordering the North Sea commenced in the early 1960s. To date, a total of 112 marine fish species have been recorded, a high proportion of the total inshore fish species complement of shallow North Sea British waters. The unrecorded top predators, such as large sharks, swordfish and tuna are not regularly observed in waters fish diversity and abundance in large industrialised estuaries such as the Thames and the Firth of Forth. Linked to spawning and nursery habitat gain, smelt, Osmerus eperlangus, and bass, Dicentrarchus labrax, have greatly increased in abundance. There is no evidence for a decline in species richness since the 1970s. However, elasmobranch species number has declined while two species Raja clavata and Scyliorhinus canicula have remained abundant and one, Mustelus asterias, has increased in abundance. It is argued that overexploitation and habitat destruction remain, as they have been for the last 300 years, the most serious threats to the health of North Sea inshore fish communities. There are no clear signs that climate change is causing species loss, although it may be influencing relative species abundance as species at the southern edge of their range such as the viviparous blenny, Zoarces viviparous, have declined in the southern British North Sea. Power station water temperature records do not show a warming trend, in some estuarine locations temperature has declined with reduced thermal pollution; the temperature record cannot explain the observed major changes in fish relative abundance observed since the 1970s.

  8. Vector species richness increases haemorrhagic disease prevalence through functional diversity modulating the duration of seasonal transmission.

    Science.gov (United States)

    Park, Andrew W; Cleveland, Christopher A; Dallas, Tad A; Corn, Joseph L

    2016-06-01

    Although many parasites are transmitted between hosts by a suite of arthropod vectors, the impact of vector biodiversity on parasite transmission is poorly understood. Positive relationships between host infection prevalence and vector species richness (SR) may operate through multiple mechanisms, including (i) increased vector abundance, (ii) a sampling effect in which species of high vectorial capacity are more likely to occur in species-rich communities, and (iii) functional diversity whereby communities comprised species with distinct phenologies may extend the duration of seasonal transmission. Teasing such mechanisms apart is impeded by a lack of appropriate data, yet could highlight a neglected role for functional diversity in parasite transmission. We used statistical modelling of extensive host, vector and microparasite data to test the hypothesis that functional diversity leading to longer seasonal transmission explained variable levels of disease in a wildlife population. We additionally developed a simple transmission model to guide our expectation of how an increased transmission season translates to infection prevalence. Our study demonstrates that vector SR is associated with increased levels of disease reporting, but not via increases in vector abundance or via a sampling effect. Rather, the relationship operates by extending the length of seasonal transmission, in line with theoretical predictions.

  9. RELATIONSHIPS OF ALIEN PLANT SPECIES ABUNDANCE TO RIPARIAN VEGETATION, ENVIRONMENT, AND DISTURBANCE

    Science.gov (United States)

    Riparian ecosystems are often invaded by alien species. We evaluated vegetation, environment, and disturbance conditions and their interrelationships with alien species abundance along reaches of 29 streams in eastern Oregon, USA. Using flexible-BETA clustering, indicator species...

  10. Plant trait-species abundance relationships vary with environmental properties in subtropical forests in eastern china.

    Directory of Open Access Journals (Sweden)

    En-Rong Yan

    Full Text Available Understanding how plant trait-species abundance relationships change with a range of single and multivariate environmental properties is crucial for explaining species abundance and rarity. In this study, the abundance of 94 woody plant species was examined and related to 15 plant leaf and wood traits at both local and landscape scales involving 31 plots in subtropical forests in eastern China. Further, plant trait-species abundance relationships were related to a range of single and multivariate (PCA axes environmental properties such as air humidity, soil moisture content, soil temperature, soil pH, and soil organic matter, nitrogen (N and phosphorus (P contents. At the landscape scale, plant maximum height, and twig and stem wood densities were positively correlated, whereas mean leaf area (MLA, leaf N concentration (LN, and total leaf area per twig size (TLA were negatively correlated with species abundance. At the plot scale, plant maximum height, leaf and twig dry matter contents, twig and stem wood densities were positively correlated, but MLA, specific leaf area, LN, leaf P concentration and TLA were negatively correlated with species abundance. Plant trait-species abundance relationships shifted over the range of seven single environmental properties and along multivariate environmental axes in a similar way. In conclusion, strong relationships between plant traits and species abundance existed among and within communities. Significant shifts in plant trait-species abundance relationships in a range of environmental properties suggest strong environmental filtering processes that influence species abundance and rarity in the studied subtropical forests.

  11. Effects of urbanization on carnivore species distribution and richness

    Science.gov (United States)

    Ordenana, Miguel A.; Crooks, Kevin R.; Boydston, Erin E.; Fisher, Robert N.; Lyren, Lisa M.; Siudyla, Shalene; Haas, Christopher D.; Harris, Sierra; Hathaway, Stacie A.; Turschak, Greta M.; Miles, A. Keith; Van Vuren, Dirk H.

    2010-01-01

    Urban development can have multiple effects on mammalian carnivore communities. We conducted a meta-analysis of 7,929 photographs from 217 localities in 11 camera-trap studies across coastal southern California to describe habitat use and determine the effects of urban proximity (distance to urban edge) and intensity (percentage of area urbanized) on carnivore occurrence and species richness in natural habitats close to the urban boundary. Coyotes (Canis latrans) and bobcats (Lynx rufus) were distributed widely across the region. Domestic dogs (Canis lupus familiaris), striped skunks (Mephitis mephitis), raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), mountain lions (Puma concolor), and Virginia opossums (Didelphis virginiana) were detected less frequently, and long-tailed weasels (Mustela frenata), American badgers (Taxidea taxus), western spotted skunks (Spilogale gracilis), and domestic cats (Felis catus) were detected rarely. Habitat use generally reflected availability for most species. Coyote and raccoon occurrence increased with both proximity to and intensity of urbanization, whereas bobcat, gray fox, and mountain lion occurrence decreased with urban proximity and intensity. Domestic dogs and Virginia opossums exhibited positive and weak negative relationships, respectively, with urban intensity but were unaffected by urban proximity. Striped skunk occurrence increased with urban proximity but decreased with urban intensity. Native species richness was negatively associated with urban intensity but not urban proximity, probably because of the stronger negative response of individual species to urban intensity.

  12. Bryophyte species richness on retention aspens recovers in time but community structure does not.

    Science.gov (United States)

    Oldén, Anna; Ovaskainen, Otso; Kotiaho, Janne S; Laaka-Lindberg, Sanna; Halme, Panu

    2014-01-01

    Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer 'lifeboats' to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L.) retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 'retention aspens' on 14 differently aged retention sites with 102 'conservation aspens' on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered) and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20-30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20-30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old-growth forests.

  13. Bryophyte species richness on retention aspens recovers in time but community structure does not.

    Directory of Open Access Journals (Sweden)

    Anna Oldén

    Full Text Available Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer 'lifeboats' to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L. retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 'retention aspens' on 14 differently aged retention sites with 102 'conservation aspens' on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20-30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20-30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old

  14. Integrative modelling reveals mechanisms linking productivity and plant species richness.

    Science.gov (United States)

    Grace, James B; Anderson, T Michael; Seabloom, Eric W; Borer, Elizabeth T; Adler, Peter B; Harpole, W Stanley; Hautier, Yann; Hillebrand, Helmut; Lind, Eric M; Pärtel, Meelis; Bakker, Jonathan D; Buckley, Yvonne M; Crawley, Michael J; Damschen, Ellen I; Davies, Kendi F; Fay, Philip A; Firn, Jennifer; Gruner, Daniel S; Hector, Andy; Knops, Johannes M H; MacDougall, Andrew S; Melbourne, Brett A; Morgan, John W; Orrock, John L; Prober, Suzanne M; Smith, Melinda D

    2016-01-21

    How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems.

  15. Environmental correlates underlying elevational richness, abundance, and biomass patterns of multi-feeding guilds in litter invertebrates across the treeline.

    Science.gov (United States)

    Xu, Guorui; Zhang, Shuang; Zhang, Yuxin; Ma, Keming

    2018-08-15

    Elevational richness patterns and underlying environmental correlates have contributed greatly to a range of general theories of biodiversity. However, the mechanisms underlying elevational abundance and biomass patterns across several trophic levels in belowground food webs remain largely unknown. In this study, we aimed to disentangle the relationships between the elevational patterns of different trophic levels of litter invertebrates and their underlying environmental correlates for two contrasting ecosystems separated by the treeline. We sampled 119 plots from 1020 to 1770 asl in forest and 21 plots from 1790 to 2280 asl in meadow on Dongling Mountain, northwest of Beijing, China. Four functional guilds were divided based on feeding regime: omnivores, herbivores, predators, and detritivores. We used eigenvector-based spatial filters to account for spatial autocorrelation and multi-model selection to determine the best environmental correlates for the community attributes of the different feeding guilds. The results showed that the richness, abundance and biomass of omnivores declined with increasing elevation in the meadow, whereas there was a hump-shaped richness pattern for detritivores. The richness and abundance of different feeding guilds were positively correlated in the forest, while not in the meadow. In the forest, the variances of richness in omnivores, predators, and detritivores were mostly correlated with litter thickness, with omnivores being best explained by mean annual temperature in the meadow. In conclusion, hump-shaped elevational richness, abundance and biomass patterns driven by the forest gradient below the treeline existed in all feeding guilds of litter invertebrates. Climate replaced productivity as the primary factor that drove the richness patterns of omnivores above the treeline, whereas heterogeneity replaced climate for herbivores. Our results highlight that the correlated elevational richness, abundance, and biomass patterns of

  16. Primary controls on species richness in higher taxa.

    Science.gov (United States)

    Rabosky, Daniel L

    2010-12-01

    The disparity in species richness across the tree of life is one of the most striking and pervasive features of biological diversity. Some groups are exceptionally diverse, whereas many other groups are species poor. Differences in diversity among groups are frequently assumed to result from primary control by differential rates of net diversification. However, a major alternative explanation is that ecological and other factors exert primary control on clade diversity, such that apparent variation in net diversification rates is a secondary consequence of ecological limits on clade growth. Here, I consider a likelihood framework for distinguishing between these competing hypotheses. I incorporate hierarchical modeling to explicitly relax assumptions about the constancy of diversification rates across clades, and I propose several statistics for a posteriori evaluation of model adequacy. I apply the framework to a recent dated phylogeny of ants. My results reject the hypothesis that net diversification rates exert primary control on species richness in this group and demonstrate that clade diversity is better explained by total time-integrated speciation. These results further suggest that it may not possible to estimate meaningful speciation and extinction rates from higher-level phylogenies of extant taxa only.

  17. Functional redundancy patterns reveal non-random assembly rules in a species-rich marine assemblage.

    Directory of Open Access Journals (Sweden)

    Nicolas Guillemot

    Full Text Available The relationship between species and the functional diversity of assemblages is fundamental in ecology because it contains key information on functional redundancy, and functionally redundant ecosystems are thought to be more resilient, resistant and stable. However, this relationship is poorly understood and undocumented for species-rich coastal marine ecosystems. Here, we used underwater visual censuses to examine the patterns of functional redundancy for one of the most diverse vertebrate assemblages, the coral reef fishes of New Caledonia, South Pacific. First, we found that the relationship between functional and species diversity displayed a non-asymptotic power-shaped curve, implying that rare functions and species mainly occur in highly diverse assemblages. Second, we showed that the distribution of species amongst possible functions was significantly different from a random distribution up to a threshold of ∼90 species/transect. Redundancy patterns for each function further revealed that some functions displayed fast rates of increase in redundancy at low species diversity, whereas others were only becoming redundant past a certain threshold. This suggested non-random assembly rules and the existence of some primordial functions that would need to be fulfilled in priority so that coral reef fish assemblages can gain a basic ecological structure. Last, we found little effect of habitat on the shape of the functional-species diversity relationship and on the redundancy of functions, although habitat is known to largely determine assemblage characteristics such as species composition, biomass, and abundance. Our study shows that low functional redundancy is characteristic of this highly diverse fish assemblage, and, therefore, that even species-rich ecosystems such as coral reefs may be vulnerable to the removal of a few keystone species.

  18. Local and Landscape Correlates of Spider Activity Density and Species Richness in Urban Gardens.

    Science.gov (United States)

    Otoshi, Michelle D; Bichier, Peter; Philpott, Stacy M

    2015-08-01

    Urbanization is a major threat to arthropod biodiversity and abundance due to reduction and loss of suitable natural habitat. Green spaces and small-scale agricultural areas may provide habitat and resources for arthropods within densely developed cities. We studied spider activity density (a measure of both abundance and degree of movement) and diversity in urban gardens in Santa Cruz, Santa Clara, and Monterey counties in central California, USA. We sampled for spiders with pitfall traps and sampled 38 local site characteristics for 5 mo in 19 garden sites to determine the relative importance of individual local factors. We also analyzed 16 landscape variables at 500-m and 1-km buffers surrounding each garden to determine the significance of landscape factors. We identified individuals from the most common families to species and identified individuals from other families to morphospecies. Species from the families Lycosidae and Gnaphosidae composed 81% of total adult spider individuals. Most of the significant factors that correlated with spider activity density and richness were local rather than landscape factors. Spider activity density and richness increased with mulch cover and flowering plant species, and decreased with bare soil. Thus, changes in local garden management have the potential to promote diversity of functionally important spiders in urban environments. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Fish and phytoplankton exhibit contrasting temporal species abundance patterns in a dynamic north temperate lake.

    Directory of Open Access Journals (Sweden)

    Gretchen J A Hansen

    Full Text Available Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of "core" (common occurrence and high abundance and "occasional" (rare occurrence and low abundance species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions.

  20. Fish and Phytoplankton Exhibit Contrasting Temporal Species Abundance Patterns in a Dynamic North Temperate Lake

    Science.gov (United States)

    Hansen, Gretchen J. A.; Carey, Cayelan C.

    2015-01-01

    Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of “core” (common occurrence and high abundance) and “occasional” (rare occurrence and low abundance) species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions. PMID:25651399

  1. Biogeography of species richness gradients : Linking adaptive traits, demography and diversification

    NARCIS (Netherlands)

    Carnicer, Jofre; Brotons, Lluis; Stefanescu, Constanti; Penuelas, Josep

    Here we review how adaptive traits contribute to the emergence and maintenance of species richness gradients through their influence on demographic and diversification processes. We start by reviewing how demographic dynamics change along species richness gradients. Empirical studies show that

  2. Solution of the spatial neutral model yields new bounds on the Amazonian species richness

    Science.gov (United States)

    Shem-Tov, Yahav; Danino, Matan; Shnerb, Nadav M.

    2017-02-01

    Neutral models, in which individual agents with equal fitness undergo a birth-death-mutation process, are very popular in population genetics and community ecology. Usually these models are applied to populations and communities with spatial structure, but the analytic results presented so far are limited to well-mixed or mainland-island scenarios. Here we combine analytic results and numerics to obtain an approximate solution for the species abundance distribution and the species richness for the neutral model on continuous landscape. We show how the regional diversity increases when the recruitment length decreases and the spatial segregation of species grows. Our results are supported by extensive numerical simulations and allow one to probe the numerically inaccessible regime of large-scale systems with extremely small mutation/speciation rates. Model predictions are compared with the findings of recent large-scale surveys of tropical trees across the Amazon basin, yielding new bounds for the species richness (between 13100 and 15000) and the number of singleton species (between 455 and 690).

  3. Pollen Deposition Is More Important than Species Richness for Seed Set in Luffa Gourd.

    Science.gov (United States)

    Ali, M; Saeed, S; Sajjad, A

    2016-10-01

    In the context of global biodiversity decline, it is imperative to understand the different aspects of bee communities for sustaining the vital ecosystem service of pollination. Bee species can be assigned to functional groups (average difference among species in functionally related traits) on the basis of complementarity (trait variations exhibited by individual organisms) in their behavior but is not yet known which functional group trait is most important for seed set. In this study, first, the functional groups of bees were made based on their five selected traits (pollen deposition, visitation rate, stay time, visiting time of the day, body size) and then related to the seed set of obligate cross-pollinated Luffa gourd (Luffa aegyptiaca). We found that bee diversity and abundance differed significantly among the studied plots, but only the bee species richness was positively related to the seed set. Functional group diversity in terms of pollen deposition explained even more of the variance in seed set (r 2  = 0.74) than did the species richness (r 2  = 0.53) making it the most important trait of bee species for predicting the crop reproductive success.

  4. Species diversity and abundance of wild birds in Dagona-Waterfowl ...

    African Journals Online (AJOL)

    hope&shola

    The study of bird species diversity and richness in Dagona-Waterfowl sanctuary was carried out in early wet and late dry ... conservation of important species that rural inhabitants ... wetland of international importance on waterfowl habitat,.

  5. Species richness and structure of an anuran community in an Atlantic Forest site in southern Brazil

    Directory of Open Access Journals (Sweden)

    Adriele Karlokoski Cunha

    2010-06-01

    Full Text Available The species richness and spatial distribution of an anuran community were studied over 12 months in an Atlantic Forest area in São José dos Pinhais Municipality, Paraná State, southern Brazil. During field surveys, we registered 32 species from ten families: Brachycephalidae (2, Bufonidae (2, Centrolenidae (1, Cycloramphidae (1, Hemiphractidae (1, Hylidae (18, Hylodidae (1, Leiuperidae (2, Leptodactylidae (3, and Microhylidae (1. Sixteen species were registered in open areas, while seventeen species were found on forest borders and twenty species in forest areas. In relation to the microhabitat utilization, species were registered according to stratum of vocalization: 1 on the ground (eight; 2 in the water (two; 3 in the lower stratum (eleven; 4 in the intermediate stratum (five; 5 in the upper stratum (four. Five species were abundant (15.6%, while twelve were common (37.5%, and fifteen were considered rare (46.9%. The biological aspects of the majority of the species described in this work as related to forest areas are not well known. This fact reinforces the importance of Atlantic Forest conservation.

  6. Species composition, abundance and distribution of hydromedusae from Dharamtar estuarine system, adjoining Bombay Harbour

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.; Tiwari, L.R.; Nair, V.R.

    Species composition, abundance and distribution of hydromedusae from Dharamtar estuarine system, adjoining Bombay Harbour, Maharashtra, India were investigated during 1984-1985. Twenty six species belonging to 19 genera were obtained from this area...

  7. New records and detailed distribution and abundance of selected arthropod species collected between 1999 and 2011 in Azorean native forests

    DEFF Research Database (Denmark)

    Borges, Paulo A. V.; Gaspar, Clara; Crespo, Luís Carlos Fonseca

    2016-01-01

    Background In this contribution we present detailed distribution and abundance data for arthropod species identified during the BALA – Biodiversity of Arthropods from the Laurisilva of the Azores (1999-2004) and BALA2 projects (2010-2011) from 18 native forest fragments inseven of the nine Azorean...... islands (all excluding Graciosa and Corvo islands, which have no native forest left). New information Of the total 286 species identified, 81% were captured between 1999 and 2000, a period during which only 39% of all the samples were collected. On average, arthropod richness for each island increased...

  8. Species richness of vascular plants, bryophytes, and lichens along an altitudinal gradient in western Norway

    Science.gov (United States)

    Grytnes, John Arvid; Heegaard, Einar; Ihlen, Per G.

    2006-05-01

    Species richness patterns of ground-dwelling vascular plants, bryophytes, and lichens were compared along an altitudinal gradient (310-1135 m a.s.l.), in western Norway. Total species richness peaked at intermediate altitudes, vascular plant species richness peaked immediately above the forest limit (at 600-700 m a.s.l.), bryophyte species richness had no statistically significant trend, whereas lichen richness increased from the lowest point and up to the forest limit, with no trend above. It is proposed that the pattern in vascular plant species richness is enhanced by an ecotone effect. Bryophyte species richness responds to local scale factors whereas the lichen species richness may be responding to the shading from the forest trees.

  9. Relations of Environmental Factors with Mussel-Species Richness in the Neversink River, New York

    Science.gov (United States)

    Baldigo, Barry P.; Ernst, Anne G.; Schuler, George E.; Apse, Colin D.

    2007-01-01

    the Neversink Reservoir that mimic the river?s original flow patterns have recently been proposed by TNC and could benefit the established mussel populations and aquatic communities. The ability to protect mussel populations and the potential to increase mussel richness in the Neversink River is unknown, however, because the environmental factors that affect the seven mussel species are poorly defined, and the distribution of mussel beds is patchy and thus difficult to quantify. In 1997, the U.S. Geological Survey, in cooperation with TNC, began a 6-year study along the Neversink River and its tributaries to (1) document the current distribution of each mussel species, (2) assess environmental factors in relation to mussel-species richness and distribution, and (3) identify the factors that most strongly affect mussel populations and develop an equation that relates environmental factors to mussel-species richness. This report (a) summarizes the methods used to quantify or qualify environmental factors and mussel-species distribution and abundance, (b) presents a list of environmental factors that were correlated with mussel-species richness, and (c) offers an empirical model to predict richness of mussel species in benthic communities throughout the basin.

  10. Where to nest? Ecological determinants of chimpanzee nest abundance and distribution at the habitat and tree species scale.

    Science.gov (United States)

    Carvalho, Joana S; Meyer, Christoph F J; Vicente, Luis; Marques, Tiago A

    2015-02-01

    Conversion of forests to anthropogenic land-uses increasingly subjects chimpanzee populations to habitat changes and concomitant alterations in the plant resources available to them for nesting and feeding. Based on nest count surveys conducted during the dry season, we investigated nest tree species selection and the effect of vegetation attributes on nest abundance of the western chimpanzee, Pan troglodytes verus, at Lagoas de Cufada Natural Park (LCNP), Guinea-Bissau, a forest-savannah mosaic widely disturbed by humans. Further, we assessed patterns of nest height distribution to determine support for the anti-predator hypothesis. A zero-altered generalized linear mixed model showed that nest abundance was negatively related to floristic diversity (exponential form of the Shannon index) and positively with the availability of smaller-sized trees, reflecting characteristics of dense-canopy forest. A positive correlation between nest abundance and floristic richness (number of plant species) and composition indicated that species-rich open habitats are also important in nest site selection. Restricting this analysis to feeding trees, nest abundance was again positively associated with the availability of smaller-sized trees, further supporting the preference for nesting in food tree species from dense forest. Nest tree species selection was non-random, and oil palms were used at a much lower proportion (10%) than previously reported from other study sites in forest-savannah mosaics. While this study suggests that human disturbance may underlie the exclusive arboreal nesting at LCNP, better quantitative data are needed to determine to what extent the construction of elevated nests is in fact a response to predators able to climb trees. Given the importance of LCNP as refuge for Pan t. verus our findings can improve conservation decisions for the management of this important umbrella species as well as its remaining suitable habitats. © 2014 Wiley Periodicals, Inc.

  11. Temporal-spatial dynamics in orthoptera in relation to nutrient availability and plant species richness.

    Directory of Open Access Journals (Sweden)

    Rob J J Hendriks

    Full Text Available Nutrient availability in ecosystems has increased dramatically over the last century. Excess reactive nitrogen deposition is known to negatively impact plant communities, e.g. by changing species composition, biomass and vegetation structure. In contrast, little is known on how such impacts propagate to higher trophic levels. To evaluate how nitrogen deposition affects plants and herbivore communities through time, we used extensive databases of spatially explicit historical records of Dutch plant species and Orthoptera (grasshoppers and crickets, a group of animals that are particularly susceptible to changes in the C:N ratio of their resources. We use robust methods that deal with the unstandardized nature of historical databases to test whether nitrogen deposition levels and plant richness changes influence the patterns of richness change of Orthoptera, taking into account Orthoptera species functional traits. Our findings show that effects indeed also propagate to higher trophic levels. Differences in functional traits affected the temporal-spatial dynamics of assemblages of Orthoptera. While nitrogen deposition affected plant diversity, contrary to our expectations, we could not find a strong significant effect of food related traits. However we found that species with low habitat specificity, limited dispersal capacity and egg deposition in the soil were more negativly affected by nitrogen deposition levels. Despite the lack of significant effect of plant richness or food related traits on Orthoptera, the negative effects of nitrogen detected within certain trait groups (e.g. groups with limited disperse ability could be related to subtle changes in plant abundance and plant quality. Our results, however, suggest that the changes in soil conditions (where many Orthoptera species lay their eggs or other habitat changes driven by nitrogen have a stronger influence than food related traits. To fully evaluate the negative effects of nitrogen

  12. Vascular plant and vertebrate species richness in national parks of the eastern United States

    Science.gov (United States)

    Hatfield, Jeffrey S.; Myrick, Kaci E.; Huston, Michael A.; Weckerly, Floyd W.; Green, M. Clay

    2013-01-01

    Given the estimates that species diversity is diminishing at 50-100 times the normal rate, it is critical that we be able to evaluate changes in species richness in order to make informed decisions for conserving species diversity. In this study, we examined the potential of vascular plant species richness to be used as a surrogate for vertebrate species richness in the classes of amphibians, reptiles, birds, and mammals. Vascular plants, as primary producers, represent the biotic starting point for ecological community structure and are the logical place to start for understanding vertebrate species associations. We used data collected by the United States (US) National Park Service (NPS) on species presence within parks in the eastern US to estimate simple linear regressions between plant species richness and vertebrate richness. Because environmental factors may also influence species diversity, we performed simple linear regressions of species richness versus natural logarithm of park area, park latitude, mean annual precipitation, mean annual temperature, and human population density surrounding the parks. We then combined plant species richness and environmental variables in multiple regressions to determine the variables that remained as significant predictors of vertebrate species richness. As expected, we detected significant relationships between plant species richness and amphibian, bird, and mammal species richness. In some cases, plant species richness was predicted by park area alone. Species richness of mammals was only related to plant species richness. Reptile species richness, on the other hand, was related to plant species richness, park latitude and annual precipitation, while amphibian species richness was related to park latitude, park area, and plant species richness. Thus, plant species richness predicted species richness of different vertebrate groups to varying degrees and should not be used exclusively as a surrogate for vertebrate

  13. Presence and abundance of non-native plant species associated with recent energy development in the Williston Basin

    Science.gov (United States)

    Preston, Todd M.

    2015-01-01

    The Williston Basin, located in the Northern Great Plains, is experiencing rapid energy development with North Dakota and Montana being the epicenter of current and projected development in the USA. The average single-bore well pad is 5 acres with an estimated 58,485 wells in North Dakota alone. This landscape-level disturbance may provide a pathway for the establishment of non-native plants. To evaluate potential influences of energy development on the presence and abundance of non-native species, vegetation surveys were conducted at 30 oil well sites (14 ten-year-old and 16 five-year-old wells) and 14 control sites in native prairie environments across the Williston Basin. Non-native species richness and cover were recorded in four quadrats, located at equal distances, along four transects for a total of 16 quadrats per site. Non-natives were recorded at all 44 sites and ranged from 5 to 13 species, 7 to 15 species, and 2 to 8 species at the 10-year, 5-year, and control sites, respectively. Respective non-native cover ranged from 1 to 69, 16 to 76, and 2 to 82 %. Total, forb, and graminoid non-native species richness and non-native forb cover were significantly greater at oil well sites compared to control sites. At oil well sites, non-native species richness and forb cover were significantly greater adjacent to the well pads and decreased with distance to values similar to control sites. Finally, non-native species whose presence and/or abundance were significantly greater at oil well sites relative to control sites were identified to aid management efforts.

  14. Responses of Cryptofaunal Species Richness and Trophic Potential to Coral Reef Habitat Degradation

    Directory of Open Access Journals (Sweden)

    Derek P. Manzello

    2012-02-01

    Full Text Available Coral reefs are declining worldwide as a result of many anthropogenic disturbances. This trend is alarming because coral reefs are hotspots of marine biodiversity and considered the ‘rainforests of the sea. As in the rainforest, much of the diversity on a coral reef is cryptic, remaining hidden among the cracks and crevices of structural taxa. Although the cryptofauna make up the majority of a reef’s metazoan biodiversity, we know little about their basic ecology or how these communities respond to reef degradation. Emerging research shows that the species richness of the motile cryptofauna is higher among dead (framework vs. live coral substrates and, surprisingly, increases within successively more eroded reef framework structures, ultimately reaching a maximum in dead coral rubble. Consequently, the paradigm that abundant live coral is the apex of reef diversity needs to be clarified. This provides guarded optimism amidst alarming reports of declines in live coral cover and the impending doom of coral reefs, as motile cryptic biodiversity should persist independent of live coral cover. Granted, the maintenance of this high species richness is contingent on the presence of reef rubble, which will eventually be lost due to physical, chemical, and biological erosion if not replenished by live coral calcification and mortality. The trophic potential of a reef, as inferred from the abundance of cryptic organisms, is highest on live coral. Among dead framework substrates, however, the density of cryptofauna reaches a peak at intermediate levels of degradation. In summary, the response of the motile cryptofauna, and thus a large fraction of the reef’s biodiversity, to reef degradation is more complex and nuanced than currently thought; such that species richness may be less sensitive than overall trophic function.

  15. On the dependence of speciation rates on species abundance and ...

    Indian Academy of Sciences (India)

    Unknown

    abundance largely determines the rate of generation of intraspecific endogenous genetic variation, the result obtained ... population size together with generation time emerge as important ...... wind and wave mixing of the ocean, any prolonged exis- tence of ..... epipelagic plankton size structure in high latitude oceans; J.

  16. No universal scale-dependent impacts of invasive species on native plant species richness.

    Science.gov (United States)

    Stohlgren, Thomas J; Rejmánek, Marcel

    2014-01-01

    A growing number of studies seeking generalizations about the impact of plant invasions compare heavily invaded sites to uninvaded sites. But does this approach warrant any generalizations? Using two large datasets from forests, grasslands and desert ecosystems across the conterminous United States, we show that (i) a continuum of invasion impacts exists in many biomes and (ii) many possible species-area relationships may emerge reflecting a wide range of patterns of co-occurrence of native and alien plant species. Our results contradict a smaller recent study by Powell et al. 2013 (Science 339, 316-318. (doi:10.1126/science.1226817)), who compared heavily invaded and uninvaded sites in three biomes and concluded that plant communities invaded by non-native plant species generally have lower local richness (intercepts of log species richness-log area regression lines) but steeper species accumulation with increasing area (slopes of the regression lines) than do uninvaded communities. We conclude that the impacts of plant invasions on plant species richness are not universal.

  17. Influence of temporal and spatial factors on abundance and richness of fish early stages in shallow tropical estuaries

    NARCIS (Netherlands)

    Arévalo-Frías, W.; Mendoza-Carranza, M.

    2015-01-01

    Accurate determination of abundance and richness of fish early stages in estuarine zones is critical to support management and protection plans; it is therefore necessary to consider all influential factors. Habitat diversity, seasonality, moon phase and diel variations, and their interactions are

  18. High species richness of native pollinators in Brazilian tomato crops

    Directory of Open Access Journals (Sweden)

    C. M. Silva-Neto

    Full Text Available Abstract Pollinators provide an essential service to natural ecosystems and agriculture. In tomatoes flowers, anthers are poricidal, pollen may drop from their pore when flowers are shaken by the wind. However, bees that vibrate these anthers increase pollen load on the stigma and in fruit production. The present study aimed to identify the pollinator richness of tomato flowers and investigate their morphological and functional traits related to the plant-pollinator interaction in plantations of Central Brazil. The time of anthesis, flower duration, and the number and viability of pollen grains and ovules were recorded. Floral visitors were observed and collected. Flower buds opened around 6h30 and closed around 18h00. They reopened on the following day at the same time in the morning, lasting on average 48 hours. The highest pollen availability occurred during the first hours of anthesis. Afterwards, the number of pollen grains declined, especially between 10h00 to 12h00, which is consistent with the pollinator visitation pattern. Forty bee species were found in the tomato fields, 30 of which were considered pollinators. We found that during the flowering period, plants offered an enormous amount of pollen to their visitors. These may explain the high richness and amount of bees that visit the tomato flowers in the study areas. The period of pollen availability and depletion throughout the day overlapped with the bees foraging period, suggesting that bees are highly effective in removing pollen grains from anthers. Many of these grains probably land on the stigma of the same flower, leading to self-pollination and subsequent fruit development. Native bees (Exomalopsis spp. are effective pollinators of tomato flowers and are likely to contribute to increasing crop productivity. On the other hand, here tomato flowers offer large amounts of pollen resource to a high richness and amount of bees, showing a strong plant-pollinator interaction in the

  19. High species richness of native pollinators in Brazilian tomato crops.

    Science.gov (United States)

    Silva-Neto, C M; Bergamini, L L; Elias, M A S; Moreira, G L; Morais, J M; Bergamini, B A R; Franceschinelli, E V

    2017-01-01

    Pollinators provide an essential service to natural ecosystems and agriculture. In tomatoes flowers, anthers are poricidal, pollen may drop from their pore when flowers are shaken by the wind. However, bees that vibrate these anthers increase pollen load on the stigma and in fruit production. The present study aimed to identify the pollinator richness of tomato flowers and investigate their morphological and functional traits related to the plant-pollinator interaction in plantations of Central Brazil. The time of anthesis, flower duration, and the number and viability of pollen grains and ovules were recorded. Floral visitors were observed and collected. Flower buds opened around 6h30 and closed around 18h00. They reopened on the following day at the same time in the morning, lasting on average 48 hours. The highest pollen availability occurred during the first hours of anthesis. Afterwards, the number of pollen grains declined, especially between 10h00 to 12h00, which is consistent with the pollinator visitation pattern. Forty bee species were found in the tomato fields, 30 of which were considered pollinators. We found that during the flowering period, plants offered an enormous amount of pollen to their visitors. These may explain the high richness and amount of bees that visit the tomato flowers in the study areas. The period of pollen availability and depletion throughout the day overlapped with the bees foraging period, suggesting that bees are highly effective in removing pollen grains from anthers. Many of these grains probably land on the stigma of the same flower, leading to self-pollination and subsequent fruit development. Native bees (Exomalopsis spp.) are effective pollinators of tomato flowers and are likely to contribute to increasing crop productivity. On the other hand, here tomato flowers offer large amounts of pollen resource to a high richness and amount of bees, showing a strong plant-pollinator interaction in the study agroecosystem.

  20. 1 Species Diversity and Relative Abundance.cdr

    African Journals Online (AJOL)

    Administrator

    from beach seine landings along the central coast during the study period. Landing sites were Winneba, Saltpond and Cape Coast. (Fig. 1). Fish identification was done in the laboratory using manuals (Schneider, 1990;. Kwei & Ofori-Adu, 2005). The identifications were to the family and species levels. Various fish species ...

  1. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@uts.edu.a [School of Applied Sciences, RMIT University, Victoria (Australia); Centre for Environmental Sustainability, Department of Environmental Science, University of Technology Sydney, New South Wales (Australia); Marchant, Richard [Department of Entomology, Museum of Victoria, Victoria (Australia); Schaefer, Ralf B. [School of Applied Sciences, RMIT University, Victoria (Australia); Metzeling, Leon [EPA Victoria, Macleod, Victoria (Australia); Dunlop, Jason E. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); National Research Centre for Environmental Toxicology, University of Queensland, Coopers Plains, Queensland (Australia); Choy, Satish C. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); Goonan, Peter [South Australia Environment Protection Authority, Adelaide, South Australia (Australia)

    2011-01-15

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC{sub p} value). However, at the PC{sub p} value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r{sup 2} {>=} 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  2. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    International Nuclear Information System (INIS)

    Kefford, Ben J.; Marchant, Richard; Schaefer, Ralf B.; Metzeling, Leon; Dunlop, Jason E.; Choy, Satish C.; Goonan, Peter

    2011-01-01

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC p value). However, at the PC p value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r 2 ≥ 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  3. Geography, topography, and history affect realized-to-potential tree species richness patterns in Europe

    Science.gov (United States)

    Jens-Christian Svenning; Matthew C. Fitzpatrick; Signe Normand; Catherine H. Graham; Peter B. Pearman; Louis R. Iverson; Flemming. Skov

    2010-01-01

    Environmental conditions and biotic interactions are generally thought to influence local species richness. However, immigration and the evolutionary and historical factors that shape regional species pools should also contribute to determining local species richness because local communities arise by assembly from regional species pools. Using the European tree flora...

  4. Parasites of mammals species abundance near zone Chernobyl

    International Nuclear Information System (INIS)

    Pen'kevich, V.A.

    2014-01-01

    In wildlife reserve parasitize various types of parasites: arachnids (mites) parasitic insects (horseflies, keds, mosquitoes, gnats, midges), helminths (trematodes, cestodes, nematodes and acanthocephalans) and parasitic protozoa. In quantity: 3 (beaver) to 25 species (wolf). (authors)

  5. Long-Term Changes in Species Composition and Relative Abundances of Sharks at a Provisioning Site

    OpenAIRE

    Brunnschweiler, Juerg M.; Abrantes, Kátya G.; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-...

  6. Habitat availability does not explain the species richness patterns of European lentic and lotic freshwater animals

    DEFF Research Database (Denmark)

    Dehling, D.M.; Hof, C.; Brandle, M.

    2010-01-01

    Aim In Europe, the relationships between species richness and latitude differ for lentic (standing water) and lotic (running water) species. Freshwater animals are highly dependent on suitable habitat, and thus the distribution of available habitat should strongly influence large-scale patterns...... of species richness. We tested whether habitat availability can account for the differences in species richness patterns between European lentic and lotic freshwater animals. Location Europe. Methods We compiled occurrence data of 1959 lentic and 2445 lotic species as well as data on the amount of lentic...... for previously reported latitudinal patterns in species richness. For lotic species, richness declined with latitude, whereas there was no relationship between habitat availability and latitude. For lentic species, richness showed a hump-shaped relationship with latitude, whereas available habitat increased...

  7. Species Abundance in a Forest Community in South China: A Case of Poisson Lognormal Distribution

    Institute of Scientific and Technical Information of China (English)

    Zuo-Yun YIN; Hai REN; Qian-Mei ZHANG; Shao-Lin PENG; Qin-Feng GUO; Guo-Yi ZHOU

    2005-01-01

    Case studies on Poisson lognormal distribution of species abundance have been rare, especially in forest communities. We propose a numerical method to fit the Poisson lognormal to the species abundance data at an evergreen mixed forest in the Dinghushan Biosphere Reserve, South China. Plants in the tree, shrub and herb layers in 25 quadrats of 20 m×20 m, 5 m×5 m, and 1 m×1 m were surveyed. Results indicated that: (i) for each layer, the observed species abundance with a similarly small median, mode, and a variance larger than the mean was reverse J-shaped and followed well the zero-truncated Poisson lognormal;(ii) the coefficient of variation, skewness and kurtosis of abundance, and two Poisson lognormal parameters (σ andμ) for shrub layer were closer to those for the herb layer than those for the tree layer; and (iii) from the tree to the shrub to the herb layer, the σ and the coefficient of variation decreased, whereas diversity increased. We suggest that: (i) the species abundance distributions in the three layers reflects the overall community characteristics; (ii) the Poisson lognormal can describe the species abundance distribution in diverse communities with a few abundant species but many rare species; and (iii) 1/σ should be an alternative measure of diversity.

  8. Species richness, habitable volume, and species densities in freshwater, the sea, and on land

    Directory of Open Access Journals (Sweden)

    Michael N Dawson

    2012-09-01

    Full Text Available Approximately 0.5–2.0 million eukaryotic species inhabit the seas, whereas 2.0–10.0 million inhabit freshwater or the land. Much has been made of this several-fold difference in species richness but there is little consensus about the causes. Here, I ask a related question: what is the relative density of species in marine and non-marine realms? I use recent estimates of global eukaryotic species richness and published estimates of the areal coverage and depth of habitat for freshwater, marine, and terrestrial biomes. I find that the marine realm harbors ~99.83% of the habitable volume on this planet. Eukaryotic species density of the marine realm is ~3600-fold (i.e., 3-4 orders of magnitude less than that of non-marine environments. Species–volume relationships (SVRs help reconcile actinopterygian fish diversity with global primary productivity and emphasize the interacting roles of abiotic and biotic complexity in shaping patterns of biodiversity in freshwater, the sea, and on land. Comparing SVRs of habitats within and across realms may help resolve the factors and interactions that influence species density.

  9. fish species and size distribution and abundance in different areas

    African Journals Online (AJOL)

    Larger individuals dominated in deep waters recording a mode at 45.5 cm TL. ... as a result of trophic interactions with introduced species ... sea level. The climate is equatorial with two wet seasons, one between October and. December, the ...

  10. Associations of Two Ecologically Significant Social Insect Taxa in the Litter of an Amazonian Rainforest: Is There a Relationship between Ant and Termite Species Richness?

    Directory of Open Access Journals (Sweden)

    Amy L. Mertl

    2012-01-01

    Full Text Available In spite of the ecological dominance of Neotropical ants and termites, little is understood about how their interactions influence their species richness and distribution. We surveyed ground-dwelling termite and ant species in a primary rainforest in Ecuador and analyzed ecological correlates of diversity. Termite richness was positively correlated with ant richness and abundance of twig-nesting ants. We found no evidence of competition for twigs between termites and ants. No ecological factors were correlated with termite diversity although elevation and twig and log abundance influenced ant diversity. When ant richness was compared to the richness of termites employing different predator defenses, a positive correlation was found with soldierless termites, but not genera employing chemical or mechanical defense. Our results suggest that multiple ecological factors influence ant and termite diversity, and that ant predation on termites may have a greater effect than competition between ant and termites for nest sites and food sources.

  11. Estimating the spatial and temporal distribution of species richness within Sequoia and Kings Canyon National Parks.

    Directory of Open Access Journals (Sweden)

    Steve Wathen

    Full Text Available Evidence for significant losses of species richness or biodiversity, even within protected natural areas, is mounting. Managers are increasingly being asked to monitor biodiversity, yet estimating biodiversity is often prohibitively expensive. As a cost-effective option, we estimated the spatial and temporal distribution of species richness for four taxonomic groups (birds, mammals, herpetofauna (reptiles and amphibians, and plants within Sequoia and Kings Canyon National Parks using only existing biological studies undertaken within the Parks and the Parks' long-term wildlife observation database. We used a rarefaction approach to model species richness for the four taxonomic groups and analyzed those groups by habitat type, elevation zone, and time period. We then mapped the spatial distributions of species richness values for the four taxonomic groups, as well as total species richness, for the Parks. We also estimated changes in species richness for birds, mammals, and herpetofauna since 1980. The modeled patterns of species richness either peaked at mid elevations (mammals, plants, and total species richness or declined consistently with increasing elevation (herpetofauna and birds. Plants reached maximum species richness values at much higher elevations than did vertebrate taxa, and non-flying mammals reached maximum species richness values at higher elevations than did birds. Alpine plant communities, including sagebrush, had higher species richness values than did subalpine plant communities located below them in elevation. These results are supported by other papers published in the scientific literature. Perhaps reflecting climate change: birds and herpetofauna displayed declines in species richness since 1980 at low and middle elevations and mammals displayed declines in species richness since 1980 at all elevations.

  12. Species abundance distributions : moving beyond single prediction theories to integration within an ecological framework

    NARCIS (Netherlands)

    McGill, Brian J.; Etienne, Rampal S.; Gray, John S.; Alonso, David; Anderson, Marti J.; Benecha, Habtamu Kassa; Dornelas, Maria; Enquist, Brian J.; Green, Jessica L.; He, Fangliang; Hurlbert, Allen H.; Magurran, Anne E.; Marquet, Pablo A.; Maurer, Brian A.; Ostling, Annette; Soykan, Candan U.; Ugland, Karl I.; White, Ethan P.

    2007-01-01

    Species abundance distributions (SADs) follow one of ecology's oldest and most universal laws - every community shows a hollow curve or hyperbolic shape on a histogram with many rare species and just a few common species. Here, we review theoretical, empirical and statistical developments in the

  13. Species abundance distributions: moving beyond single prediction theories to integration within an ecological framework

    NARCIS (Netherlands)

    McGill, B.J.; Etienne, R.S.; Gray, J.S.; Alonso, D.; Anderson, M.J.; Benecha, H.K.

    2007-01-01

    Species abundance distributions (SADs) follow one of ecology's oldest and most universal laws ¿ every community shows a hollow curve or hyperbolic shape on a histogram with many rare species and just a few common species. Here, we review theoretical, empirical and statistical developments in the

  14. Urbanization Alters the Influence of Weather and an Index of Forest Productivity on Avian Community Richness and Guild Abundance in the Seattle Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Benjamin Shryock

    2017-05-01

    Full Text Available Fluctuations in weather and forest productivity influence the abundance and richness of bird populations, however in a rapidly urbanizing landscape the relative importance of each factor may vary. We assessed this possibility in the Seattle, WA, USA region by correlating 10 years of bird richness and relative abundance of nine guilds indicative of their tolerance of human development, migration, diet and use of human food subsidies with an annual index of forest productivity (vegetation greenness derived from a 250 m resolution Normalized Difference Vegetation Index (NDVI product from the MODIS satellite and weather (variation in the Oceanic Niño Index, which estimates the strength of the El Niño-Southern Oscillation, a major driver of local temperature and precipitation. We found that variation in NDVI exerted a strong influence on the richness of the avian community and the abundance of guilds in landscapes undergoing active development, but was less influential in areas of established housing development or forested reserves. Relative to NDVI, weather was much less influential on the abundance of guilds at actively changing sites, and slightly more influential in forest reserves and established developments. Following the warm winter and during the dry summer associated with a strong El Niño, migrants and herbivores declined in changing landscapes, insectivores declined in established developments, and herbivores declined while synanthropic species increased in reserves. These changes may presage the effects of climate change in the Pacific Northwest, which are expected to be similar to El Niño conditions. To buffer these changes in native bird communities, planners, developers, regulators, and home owners should minimize the loss of vegetation during development and attempt to quickly achieve mature landscaping that preferably provides food and shelter for birds.

  15. Landscape variation in tree species richness in northern Iran forests.

    Science.gov (United States)

    Bourque, Charles P-A; Bayat, Mahmoud

    2015-01-01

    Mapping landscape variation in tree species richness (SR) is essential to the long term management and conservation of forest ecosystems. The current study examines the prospect of mapping field assessments of SR in a high-elevation, deciduous forest in northern Iran as a function of 16 biophysical variables representative of the area's unique physiography, including topography and coastal placement, biophysical environment, and forests. Basic to this study is the development of moderate-resolution biophysical surfaces and associated plot-estimates for 202 permanent sampling plots. The biophysical variables include: (i) three topographic variables generated directly from the area's digital terrain model; (ii) four ecophysiologically-relevant variables derived from process models or from first principles; and (iii) seven variables of Landsat-8-acquired surface reflectance and two, of surface radiance. With symbolic regression, it was shown that only four of the 16 variables were needed to explain 85% of observed plot-level variation in SR (i.e., wind velocity, surface reflectance of blue light, and topographic wetness indices representative of soil water content), yielding mean-absolute and root-mean-squared error of 0.50 and 0.78, respectively. Overall, localised calculations of wind velocity and surface reflectance of blue light explained about 63% of observed variation in SR, with wind velocity accounting for 51% of that variation. The remaining 22% was explained by linear combinations of soil-water-related topographic indices and associated thresholds. In general, SR and diversity tended to be greatest for plots dominated by Carpinus betulus (involving ≥ 33% of all trees in a plot), than by Fagus orientalis (median difference of one species). This study provides a significant step towards describing landscape variation in SR as a function of modelled and satellite-based information and symbolic regression. Methods in this study are sufficiently general to be

  16. Species richness and trait composition of butterfly assemblages change along an altitudinal gradient.

    Science.gov (United States)

    Leingärtner, Annette; Krauss, Jochen; Steffan-Dewenter, Ingolf

    2014-06-01

    Species richness patterns along altitudinal gradients are well-documented ecological phenomena, yet very little data are available on how environmental filtering processes influence the composition and traits of butterfly assemblages at high altitudes. We have studied the diversity patterns of butterfly species at 34 sites along an altitudinal gradient ranging from 600 to 2,000 m a.s.l. in the National Park Berchtesgaden (Germany) and analysed traits of butterfly assemblages associated with dispersal capacity, reproductive strategies and developmental time from lowlands to highlands, including phylogenetic analyses. We found a linear decline in butterfly species richness along the altitudinal gradient, but the phylogenetic relatedness of the butterfly assemblages did not increase with altitude. Compared to butterfly assemblages at lower altitudes, those at higher altitudes were composed of species with larger wings (on average 9%) which laid an average of 68% more eggs. In contrast, egg maturation time in butterfly assemblages decreased by about 22% along the altitudinal gradient. Further, butterfly assemblages at higher altitudes were increasingly dominated by less widespread species. Based on our abundance data, but not on data in the literature, population density increased with altitude, suggesting a reversed density-distribution relationship, with higher population densities of habitat specialists in harsh environments. In conclusion, our data provide evidence for significant shifts in the composition of butterfly assemblages and for the dominance of different traits along the altitudinal gradient. In our study, these changes were mainly driven by environmental factors, whereas phylogenetic filtering played a minor role along the studied altitudinal range.

  17. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    Directory of Open Access Journals (Sweden)

    Alessandro Ossola

    2015-10-01

    Full Text Available Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i ant abundance and species richness would be higher in high-complexity urban habitats, (ii ant assemblages would differ between low- and high-complexity habitats and (iii ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.

  18. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    Science.gov (United States)

    Nash, Michael A.; Christie, Fiona J.; Hahs, Amy K.; Livesley, Stephen J.

    2015-01-01

    Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size. PMID:26528416

  19. Determinants of species richness patterns in the Netherlands across multiple taxonomic groups

    NARCIS (Netherlands)

    Schouten, M.A.; Verweij, P.A.; Barendrecht, A.; Kleukers, R.

    2009-01-01

    We examined the species richness patterns of five different species groups (mosses, reptiles and amphibians, grasshoppers and crickets, dragonflies, and hoverflies) in the Netherlands (41,500 km2) using sampling units of 5 × 5 km. We compared the spatial patterns of species richness of the five

  20. Limited sampling hampers “big data” estimation of species richness in a tropical biodiversity hotspot

    DEFF Research Database (Denmark)

    Engemann, Kristine; Enquist, Brian J.; Sandel, Brody Steven

    2015-01-01

    in Ecuador, one of the most species-rich and climatically heterogeneous biodiversity hotspots. Species richness estimates were calculated based on 205,735 georeferenced specimens of 15,788 species using the Margalef diversity index, the Chao estimator, the second-order Jackknife and Bootstrapping resampling...

  1. Ecological pattern of lichen species abundance in mixed forests of Eastern Romania

    Directory of Open Access Journals (Sweden)

    Ioana Vicol

    2016-12-01

    Full Text Available The importance of this study consists in the knowledge of the ecological attributes characteristic to mixed forestry habitats and how they affect the structure of the lichen species abundances. The field activities were performed within five forest habitat types from Moldavia Province, characterised mainly by oak mixed forests, riparian mixed forests and mixed beech forests. The habitat variables, tree variables and the lichen species abundances were analysed to get informations on the structural disimilarities, on the one hand, and relationships on the other hand. Within this study no significant disimilarities were found out from abundance lichen species point of view. The lichen species abundances are a result of interactions between components of their microhabitat and macrohabitat. The correlation analysis pointed out the preferences of lichen species to their host trees, especially Quercus and Fraxinus, altitude and tree level variables as are aspect and mosses coverage. The regression analysis has highlighted that the changes in lichen species abundances are caused by macrohabitat level predictors such as host trees represented by Fraxinus. This study demonstrates that, structure of lichen species is influenced by attributes of mixed forest habitats; therefore maintaining the diversity of tree species and ensuring the continuous occurrence of forestry land is necessary for lichen and their habitat conservation.

  2. Species richness in soil bacterial communities: a proposed approach to overcome sample size bias.

    Science.gov (United States)

    Youssef, Noha H; Elshahed, Mostafa S

    2008-09-01

    Estimates of species richness based on 16S rRNA gene clone libraries are increasingly utilized to gauge the level of bacterial diversity within various ecosystems. However, previous studies have indicated that regardless of the utilized approach, species richness estimates obtained are dependent on the size of the analyzed clone libraries. We here propose an approach to overcome sample size bias in species richness estimates in complex microbial communities. Parametric (Maximum likelihood-based and rarefaction curve-based) and non-parametric approaches were used to estimate species richness in a library of 13,001 near full-length 16S rRNA clones derived from soil, as well as in multiple subsets of the original library. Species richness estimates obtained increased with the increase in library size. To obtain a sample size-unbiased estimate of species richness, we calculated the theoretical clone library sizes required to encounter the estimated species richness at various clone library sizes, used curve fitting to determine the theoretical clone library size required to encounter the "true" species richness, and subsequently determined the corresponding sample size-unbiased species richness value. Using this approach, sample size-unbiased estimates of 17,230, 15,571, and 33,912 were obtained for the ML-based, rarefaction curve-based, and ACE-1 estimators, respectively, compared to bias-uncorrected values of 15,009, 11,913, and 20,909.

  3. Does resource availability, resource heterogeneity or species turnover mediate changes in plant species richness in grazed grasslands?

    NARCIS (Netherlands)

    Bakker, C; Blair, JM; Knapp, AK

    2003-01-01

    Grazing by large ungulates often increases plant species richness in grasslands of moderate to high productivity. In a mesic North American grassland with and without the presence of bison (Bos bison), a native ungulate grazer, three non-exclusive hypotheses for increased plant species richness in

  4. Assessing the sensitivity of avian species abundance to land cover and climate

    Science.gov (United States)

    LeBrun, Jaymi J.; Thogmartin, Wayne E.; Thompson, Frank R.; Dijak, William D.; Millspaugh, Joshua J.

    2016-01-01

    Climate projections for the Midwestern United States predict southerly climates to shift northward. These shifts in climate could alter distributions of species across North America through changes in climate (i.e., temperature and precipitation), or through climate-induced changes on land cover. Our objective was to determine the relative impacts of land cover and climate on the abundance of five bird species in the Central United States that have habitat requirements ranging from grassland and shrubland to forest. We substituted space for time to examine potential impacts of a changing climate by assessing climate and land cover relationships over a broad latitudinal gradient. We found positive and negative relationships of climate and land cover factors with avian abundances. Habitat variables drove patterns of abundance in migratory and resident species, although climate was also influential in predicting abundance for some species occupying more open habitat (i.e., prairie warbler, blue-winged warbler, and northern bobwhite). Abundance of northern bobwhite increased with winter temperature and was the species exhibiting the most significant effect of climate. Models for birds primarily occupying early successional habitats performed better with a combination of habitat and climate variables whereas models of species found in contiguous forest performed best with land cover alone. These varied species-specific responses present unique challenges to land managers trying to balance species conservation over a variety of land covers. Management activities focused on increasing forest cover may play a role in mitigating effects of future climate by providing habitat refugia to species vulnerable to projected changes. Conservation efforts would be best served focusing on areas with high species abundances and an array of habitats. Future work managing forests for resilience and resistance to climate change could benefit species already susceptible to climate impacts.

  5. Context-dependent interactions and the regulation of species richness in freshwater fish

    Science.gov (United States)

    MacDougall, Andrew S.; Harvey, Eric; McCune, Jenny L.; Nilsson, Karin A.; Bennett, Joseph; Firn, Jennifer; Bartley, Timothy; Grace, James B.; Kelly, Jocelyn; Tunney, Tyler D.; McMeans, Bailey; Matsuzaki, Shin-Ichiro S.; Kadoya, Taku; Esch, Ellen; Cazelles, Kevin; Lester, Nigel; McCann, Kevin S.

    2018-01-01

    Species richness is regulated by a complex network of scale-dependent processes. This complexity can obscure the influence of limiting species interactions, making it difficult to determine if abiotic or biotic drivers are more predominant regulators of richness. Using integrative modeling of freshwater fish richness from 721 lakes along an 11olatitudinal gradient, we find negative interactions to be a relatively minor independent predictor of species richness in lakes despite the widespread presence of predators. Instead, interaction effects, when detectable among major functional groups and 231 species pairs, were strong, often positive, but contextually dependent on environment. These results are consistent with the idea that negative interactions internally structure lake communities but do not consistently ‘scale-up’ to regulate richness independently of the environment. The importance of environment for interaction outcomes and its role in the regulation of species richness highlights the potential sensitivity of fish communities to the environmental changes affecting lakes globally.

  6. Landscape variation in tree species richness in northern Iran forests.

    Directory of Open Access Journals (Sweden)

    Charles P-A Bourque

    Full Text Available Mapping landscape variation in tree species richness (SR is essential to the long term management and conservation of forest ecosystems. The current study examines the prospect of mapping field assessments of SR in a high-elevation, deciduous forest in northern Iran as a function of 16 biophysical variables representative of the area's unique physiography, including topography and coastal placement, biophysical environment, and forests. Basic to this study is the development of moderate-resolution biophysical surfaces and associated plot-estimates for 202 permanent sampling plots. The biophysical variables include: (i three topographic variables generated directly from the area's digital terrain model; (ii four ecophysiologically-relevant variables derived from process models or from first principles; and (iii seven variables of Landsat-8-acquired surface reflectance and two, of surface radiance. With symbolic regression, it was shown that only four of the 16 variables were needed to explain 85% of observed plot-level variation in SR (i.e., wind velocity, surface reflectance of blue light, and topographic wetness indices representative of soil water content, yielding mean-absolute and root-mean-squared error of 0.50 and 0.78, respectively. Overall, localised calculations of wind velocity and surface reflectance of blue light explained about 63% of observed variation in SR, with wind velocity accounting for 51% of that variation. The remaining 22% was explained by linear combinations of soil-water-related topographic indices and associated thresholds. In general, SR and diversity tended to be greatest for plots dominated by Carpinus betulus (involving ≥ 33% of all trees in a plot, than by Fagus orientalis (median difference of one species. This study provides a significant step towards describing landscape variation in SR as a function of modelled and satellite-based information and symbolic regression. Methods in this study are sufficiently

  7. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    Science.gov (United States)

    Brunnschweiler, Juerg M; Abrantes, Kátya G; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion among shark

  8. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    Directory of Open Access Journals (Sweden)

    Juerg M Brunnschweiler

    Full Text Available Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive

  9. Estimating species occurrence, abundance, and detection probability using zero-inflated distributions.

    Science.gov (United States)

    Wenger, Seth J; Freeman, Mary C

    2008-10-01

    Researchers have developed methods to account for imperfect detection of species with either occupancy (presence absence) or count data using replicated sampling. We show how these approaches can be combined to simultaneously estimate occurrence, abundance, and detection probability by specifying a zero-inflated distribution for abundance. This approach may be particularly appropriate when patterns of occurrence and abundance arise from distinct processes operating at differing spatial or temporal scales. We apply the model to two data sets: (1) previously published data for a species of duck, Anas platyrhynchos, and (2) data for a stream fish species, Etheostoma scotti. We show that in these cases, an incomplete-detection zero-inflated modeling approach yields a superior fit to the data than other models. We propose that zero-inflated abundance models accounting for incomplete detection be considered when replicate count data are available.

  10. The effects of land-use change on arthropod richness and abundance on Santa Maria Island (Azores)

    DEFF Research Database (Denmark)

    Meijer, Seline S.; Whittaker, Robert J.; Borges, P. A. V.

    2011-01-01

    and abundance change with increasing distance from the native forest in adjacent habitat types in Santa Maria Island, the Azores. Arthropods were sampled in four 150 m long transects in each habitat type. Arthropods were identified to species level and classified as Azorean endemic, single-island endemic (SIE...

  11. Zooplankton abundance, species composition and ecology of tropical high-mountain crater lake Wonchi, Ethiopia

    Directory of Open Access Journals (Sweden)

    Fasil Degefu

    2014-11-01

    Full Text Available The highlands of Ethiopia represent some of the remnants of undisturbed aquatic ecosystems; they are however highly threatened by significant socio–economic developments and associated anthropogenic impacts. Lake Wonchi is one of the few remaining fairly pristine high–mountain crater lakes in the central highlands and has never been investigated in detail. We present a first study on zooplankton taxa composition, abundance and biomass conducted over more than one year including the underlying environmental drivers. The lake is basic (pH 7.9-8.9, dilute (specific conductivity 185-245 µS cm-1 and oligotrophic with mean trophic status index of 36. The zooplankton community composition showed low species richness comprising a total of fourteen taxa with six cladocerans, one copepod and seven rotifers. Simpson´s index of diversity with values between 0.6 and 0.8 pointed towards a homogenous taxa occurrence within the single sample units. The overall mean (±SD standing biomass of zooplankton was 62.02±25.76 mg dry mass m-3,which is low compared to other highland and rift valley lakes in Ethiopia. Cyclopoid copepods, in particular Thermocyclops ethiopiensis were the most abundant group and contributed 50% to the total zooplankton abundance followed by cladocerans (38% and rotifers (12%. Non-metric multi-dimensional scaling resulted in a 3-dimensional model, which revealed similar community composition on successive sampling dates except in December/January and May. Temperature, alkalinity, conductivity and nitrate-N had significant influence on this seasonal pattern. A weak, but significant positive correlation (r=0.482, N=20, P=0.037 between Chlorophyll a and zooplankton biomass mirrors a bottom-up effect of phytoplankton biomass on zooplankton dynamics. The zooplankton of Lake Wonchi displayed some degree of segregation along the epi– and metalimnion during this study, but diel vertical migration was not observed. The results show that fish

  12. Oxygen isotopic abundances in calcium- aluminum-rich inclusions from ordinary chondrites: implications for nebular heterogeneity.

    Science.gov (United States)

    McKeegan, K D; Leshin, L A; Russell, S S; MacPherson, G J

    1998-04-17

    The oxygen isotopic compositions of two calcium-aluminum-rich inclusions (CAIs) from the unequilibrated ordinary chondrite meteorites Quinyambie and Semarkona are enriched in 16O by an amount similar to that in CAIs from carbonaceous chondrites. This may indicate that most CAIs formed in a restricted region of the solar nebula and were then unevenly distributed throughout the various chondrite accretion regions. The Semarkona CAI is isotopically homogeneous and contains highly 16O-enriched melilite, supporting the hypothesis that all CAI minerals were originally 16O-rich, but that in most carbonaceous chondrite inclusions some minerals exchanged oxygen isotopes with an external reservoir following crystallization.

  13. Sponge species composition, abundance, and cover in marine lakes and coastal mangroves in Berau, Indonesia

    NARCIS (Netherlands)

    Becking, L.E.; Cleary, D.F.R.; Voogd, de N.J.

    2013-01-01

    We compared the species composition, abundance, and cover of sponges in 2 marine lakes (Kakaban Lake and Haji Buang Lake) and adjacent coastal mangroves on the islands of Kakaban and Maratua in the Berau region of Indonesia. We recorded a total of 115 sponge species, 33 of which were restricted to

  14. Chemical content of the circumstellar envelope of the oxygen-rich AGB star R Doradus. Non-LTE abundance analysis of CO, SiO, and HCN

    Science.gov (United States)

    Van de Sande, M.; Decin, L.; Lombaert, R.; Khouri, T.; de Koter, A.; Wyrowski, F.; De Nutte, R.; Homan, W.

    2018-01-01

    Context. The stellar outflows of low- to intermediate-mass stars are characterised by a rich chemistry. Condensation of molecular gas species into dust grains is a key component in a chain of physical processes that leads to the onset of a stellar wind. In order to improve our understanding of the coupling between the micro-scale chemistry and macro-scale dynamics, we need to retrieve the abundance of molecules throughout the outflow. Aims: Our aim is to determine the radial abundance profile of SiO and HCN throughout the stellar outflow of R Dor, an oxygen-rich AGB star with a low mass-loss rate. SiO is thought to play an essential role in the dust-formation process of oxygen-rich AGB stars. The presence of HCN in an oxygen-rich environment is thought to be due to non-equilibrium chemistry in the inner wind. Methods: We analysed molecular transitions of CO, SiO, and HCN measured with the APEX telescope and all three instruments on the Herschel Space Observatory, together with data available in the literature. Photometric data and the infrared spectrum measured by ISO-SWS were used to constrain the dust component of the outflow. Using both continuum and line radiative transfer methods, a physical envelope model of both gas and dust was established. We performed an analysis of the SiO and HCN molecular transitions in order to calculate their abundances. Results: We have obtained an envelope model that describes the dust and the gas in the outflow, and determined the abundance of SiO and HCN throughout the region of the stellar outflow probed by our molecular data. For SiO, we find that the initial abundance lies between 5.5 × 10-5 and 6.0 × 10-5 with respect to H2. The abundance profile is constant up to 60 ± 10 R∗, after which it declines following a Gaussian profile with an e-folding radius of 3.5 ± 0.5 × 1013 cm or 1.4 ± 0.2 R∗. For HCN, we find an initial abundance of 5.0 × 10-7 with respect to H2. The Gaussian profile that describes the decline

  15. Peninsula Effects on Birds in a Coastal Landscape: Are Coves More Species Rich than Lobes?

    Directory of Open Access Journals (Sweden)

    Sam Riffell

    2012-10-01

    Full Text Available Peninsula effects - decreasing richness with increasing distance along peninsula lobes - have been identified for many taxa on large peninsulas. Peninsula effects are caused by differences in colonization and extinction predicted by island biogeography or by environmental gradients along the peninsula. We compared species-area regressions for cove patches (i.e., mainland to regressions for lobe patches (i.e., on peninsula tips for wet meadow birds along a highly interdigitated shoreline (northern Lake Huron, USA. We conducted analysis both with and without accounting for variation in habitat and landscape characteristics (i.e., environmental gradients of wet meadows. Species-area regressions for coves did not differ from lobes, nor did these results differ when we accounted for gradients. Similarly, few species were more abundant in coves. Peninsula effects may have been lacking because lobe patches were located ≈ 800 m on average from the mainland, and birds are highly mobile and can easily sample patches over these distances. One important caveat was that wet meadow patches > 5 ha were located in coves, so coves would still be important considerations in conservation plans because of the contribution of large patches to reproductive success, dispersal and population dynamics.

  16. Kleptoparasitic behavior and species richness at Mt. Graham red squirrel middens

    Science.gov (United States)

    Andrew J. Edelman; John L. Koprowski; Jennifer L. Edelman

    2005-01-01

    We used remote photography to assess the frequency of inter- and intra-specific kleptoparasitism and species richness at Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis) middens. Remote cameras and conifer cones were placed at occupied and unoccupied middens, and random sites. Species richness of small mammals was higher at red squirrel...

  17. Scale effects and human impact on the elevational species richness gradients

    DEFF Research Database (Denmark)

    Nogues, David Bravo; Araújo, M B; Romdal, T

    2008-01-01

    ), the derived species richness pattern changed progressively from hump-shaped to a monotonic pattern as the scale of extent diminished. Scale effects alone gave rise to as many conflicting patterns of species richness as had previously been reported in the literature, and scale effects lent significantly...

  18. Comment on "Worldwide evidence of a unimodal relationship between productivity and plant species richness"

    Science.gov (United States)

    Tredennick, Andrew T.; Adler, Peter B.; Grace, James B.; Harpole, W Stanley; Borer, Elizabeth T.; Seabloom, Eric W.; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori A.; Brown, Cynthia S.; Buckley, Yvonne M.; Chu, Cheng-Jin; Collins, Scott L.; Crawley, Michael J.; Fay, Philip A.; Firn, Jennifer; Gruner, Daniel S.; Hagenah, Nicole; Hautier, Yann; Hector, Andy; Hillebrand, Helmut; Kirkman, Kevin P.; Knops, Johannes M. H.; Laungani, Ramesh; Lind, Eric M.; MacDougall, Andrew S.; McCulley, Rebecca L.; Mitchell, Charles E.; Moore, Joslin L.; Morgan, John W.; Orrock, John L.; Peri, Pablo L.; Prober, Suzanne M.; Risch, Anita C.; Schuetz, Martin; Speziale, Karina L.; Standish, Rachel J.; Sullivan, Lauren L.; Wardle, Glenda M.; Williams, Ryan J.; Yang, Louie H.

    2016-01-01

    Fraser et al. (Reports, 17 July 2015, p. 302) report a unimodal relationship between productivity and species richness at regional and global scales, which they contrast with the results of Adler et al. (Reports, 23 September 2011, p. 1750). However, both data sets, when analyzed correctly, show clearly and consistently that productivity is a poor predictor of local species richness.

  19. Deficit in community species richness as explained by area and isolation of sites

    DEFF Research Database (Denmark)

    Bruun, Hans Henrik

    2000-01-01

    The potential community species richness was predicted for 85 patches of seminatural grassland in an agricultural landscape in Denmark. The basis of the prediction was a very large dataset on the vegetation, soil pH and topography in Danish grasslands and related communities. Species were inserte......, community richness deficit, varied considerably among patches. Community richness deficit exhibited a negative relationship with patch area, and for small patches a positive relationship with patch isolation....

  20. Early MESSENGER Results for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

    Science.gov (United States)

    Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos

    2011-01-01

    Now that the Messenger spacecraft is in orbit about Mercury, the extended observing time enables searches for exospheric species that are less abundant or weakly emitting compared with those for which emission has previously been detected. Many of these species cannot be observed from the ground because of terrestrial atmospheric absorption. We report here on the status of MESSENGER orbital-phase searches for additional species in Mercury's exosphere.

  1. Models of alien species richness show moderate predictive accuracy and poor transferability

    Directory of Open Access Journals (Sweden)

    César Capinha

    2018-06-01

    Full Text Available Robust predictions of alien species richness are useful to assess global biodiversity change. Nevertheless, the capacity to predict spatial patterns of alien species richness remains largely unassessed. Using 22 data sets of alien species richness from diverse taxonomic groups and covering various parts of the world, we evaluated whether different statistical models were able to provide useful predictions of absolute and relative alien species richness, as a function of explanatory variables representing geographical, environmental and socio-economic factors. Five state-of-the-art count data modelling techniques were used and compared: Poisson and negative binomial generalised linear models (GLMs, multivariate adaptive regression splines (MARS, random forests (RF and boosted regression trees (BRT. We found that predictions of absolute alien species richness had a low to moderate accuracy in the region where the models were developed and a consistently poor accuracy in new regions. Predictions of relative richness performed in a superior manner in both geographical settings, but still were not good. Flexible tree ensembles-type techniques (RF and BRT were shown to be significantly better in modelling alien species richness than parametric linear models (such as GLM, despite the latter being more commonly applied for this purpose. Importantly, the poor spatial transferability of models also warrants caution in assuming the generality of the relationships they identify, e.g. by applying projections under future scenario conditions. Ultimately, our results strongly suggest that predictability of spatial variation in richness of alien species richness is limited. The somewhat more robust ability to rank regions according to the number of aliens they have (i.e. relative richness, suggests that models of aliens species richness may be useful for prioritising and comparing regions, but not for predicting exact species numbers.

  2. Determinants of Mammal and Bird Species Richness in China Based on Habitat Groups.

    Directory of Open Access Journals (Sweden)

    Haigen Xu

    Full Text Available Understanding the spatial patterns in species richness is a central issue in macroecology and biogeography. Analyses that have traditionally focused on overall species richness limit the generality and depth of inference. Spatial patterns of species richness and the mechanisms that underpin them in China remain poorly documented. We created a database of the distribution of 580 mammal species and 849 resident bird species from 2376 counties in China and established spatial linear models to identify the determinants of species richness and test the roles of five hypotheses for overall mammals and resident birds and the 11 habitat groups among the two taxa. Our result showed that elevation variability was the most important determinant of species richness of overall mammal and bird species. It is indicated that the most prominent predictors of species richness varied among different habitat groups: elevation variability for forest and shrub mammals and birds, temperature annual range for grassland and desert mammals and wetland birds, net primary productivity for farmland mammals, maximum temperature of the warmest month for cave mammals, and precipitation of the driest quarter for grassland and desert birds. Noteworthily, main land cover type was also found to obviously influence mammal and bird species richness in forests, shrubs and wetlands under the disturbance of intensified human activities. Our findings revealed a substantial divergence in the species richness patterns among different habitat groups and highlighted the group-specific and disparate environmental associations that underpin them. As we demonstrate, a focus on overall species richness alone might lead to incomplete or misguided understanding of spatial patterns. Conservation priorities that consider a broad spectrum of habitat groups will be more successful in safeguarding the multiple services of biodiversity.

  3. Do abundance distributions and species aggregation correctly predict macroecological biodiversity patterns in tropical forests?

    Science.gov (United States)

    Wiegand, Thorsten; Lehmann, Sebastian; Huth, Andreas; Fortin, Marie‐Josée

    2016-01-01

    Abstract Aim It has been recently suggested that different ‘unified theories of biodiversity and biogeography’ can be characterized by three common ‘minimal sufficient rules’: (1) species abundance distributions follow a hollow curve, (2) species show intraspecific aggregation, and (3) species are independently placed with respect to other species. Here, we translate these qualitative rules into a quantitative framework and assess if these minimal rules are indeed sufficient to predict multiple macroecological biodiversity patterns simultaneously. Location Tropical forest plots in Barro Colorado Island (BCI), Panama, and in Sinharaja, Sri Lanka. Methods We assess the predictive power of the three rules using dynamic and spatial simulation models in combination with census data from the two forest plots. We use two different versions of the model: (1) a neutral model and (2) an extended model that allowed for species differences in dispersal distances. In a first step we derive model parameterizations that correctly represent the three minimal rules (i.e. the model quantitatively matches the observed species abundance distribution and the distribution of intraspecific aggregation). In a second step we applied the parameterized models to predict four additional spatial biodiversity patterns. Results Species‐specific dispersal was needed to quantitatively fulfil the three minimal rules. The model with species‐specific dispersal correctly predicted the species–area relationship, but failed to predict the distance decay, the relationship between species abundances and aggregations, and the distribution of a spatial co‐occurrence index of all abundant species pairs. These results were consistent over the two forest plots. Main conclusions The three ‘minimal sufficient’ rules only provide an incomplete approximation of the stochastic spatial geometry of biodiversity in tropical forests. The assumption of independent interspecific placements is most

  4. Diversification of tanagers, a species rich bird group, from lowlands to montane regions of South America

    DEFF Research Database (Denmark)

    Fjeldså, Jon; Rahbek, Carsten

    2006-01-01

    in the Atlantic forests of south-eastern Brazil, and moderate densities of widespread species in the tropical lowlands. Contemporary climate explains well the variation in species richness for the 25% most widespread species; for the remaining 75% of species with more restricted distributions, variation can only...

  5. Species richness and patterns of invasion in plants, birds, and fishes in the United States

    Science.gov (United States)

    Thomas J. Stohlgren; David T. Barnett; Curtis H. Flather; Pam L. Fuller; Bruce G. Peterjohn; John T. Kartesz; Lawrence L. Master

    2006-01-01

    We quantified broad-scale patterns of species richness and species density (mean # species/km2) for native and non-indigenous plants, birds, and fishes in the continental USA and Hawaii. We hypothesized that the species density of native and non-indigenous taxa would generally decrease in northern latitudes and higher elevations following...

  6. Acoustical Scattering, Propagation, and Attenuation Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake

    Science.gov (United States)

    2015-09-30

    an area important for acoustical testing and tactical exercises, the most abundant species by biomass is Pacific hake, Merluccius productus, a fish...scattering characteristics of the animal especially if the animal has eaten hard- shelled mollusc prey. Figure 7. A dorsal scan (similar to an x-ray) of a...kHz echogram. 11 In order to generate abundance and biomass estimates for organisms using active acoustics, one assumption that can be made is

  7. On the Chemical Abundances of Miras in Clusters: V1 in the Metal-rich Globular NGC 5927

    Science.gov (United States)

    D’Orazi, V.; Magurno, D.; Bono, G.; Matsunaga, N.; Braga, V. F.; Elgueta, S. S.; Fukue, K.; Hamano, S.; Inno, L.; Kobayashi, N.; Kondo, S.; Monelli, M.; Nonino, M.; Przybilla, N.; Sameshima, H.; Saviane, I.; Taniguchi, D.; Thevenin, F.; Urbaneja-Perez, M.; Watase, A.; Arai, A.; Bergemann, M.; Buonanno, R.; Dall’Ora, M.; Da Silva, R.; Fabrizio, M.; Ferraro, I.; Fiorentino, G.; Francois, P.; Gilmozzi, R.; Iannicola, G.; Ikeda, Y.; Jian, M.; Kawakita, H.; Kudritzki, R. P.; Lemasle, B.; Marengo, M.; Marinoni, S.; Martínez-Vázquez, C. E.; Minniti, D.; Neeley, J.; Otsubo, S.; Prieto, J. L.; Proxauf, B.; Romaniello, M.; Sanna, N.; Sneden, C.; Takenaka, K.; Tsujimoto, T.; Valenti, E.; Yasui, C.; Yoshikawa, T.; Zoccali, M.

    2018-03-01

    We present the first spectroscopic abundance determination of iron, α-elements (Si, Ca, and Ti), and sodium for the Mira variable V1 in the metal-rich globular cluster NGC 5927. We use high-resolution (R ∼ 28,000), high signal-to-noise ratio (∼200) spectra collected with WINERED, a near-infrared (NIR) spectrograph covering simultaneously the wavelength range 0.91–1.35 μm. The effective temperature and the surface gravity at the pulsation phase of the spectroscopic observation were estimated using both optical (V) and NIR time-series photometric data. We found that the Mira is metal-rich ([Fe/H] = ‑0.55 ± 0.15) and moderately α-enhanced ([α/Fe] = 0.15 ± 0.01, σ = 0.2). These values agree quite well with the mean cluster abundances based on high-resolution optical spectra of several cluster red giants available in the literature ([Fe/H] = ‑ 0.47 ± 0.06, [α/Fe] = + 0.24 ± 0.05). We also found a Na abundance of +0.35 ± 0.20 that is higher than the mean cluster abundance based on optical spectra (+0.18 ± 0.13). However, the lack of similar spectra for cluster red giants and that of corrections for departures from local thermodynamical equilibrium prevents us from establishing whether the difference is intrinsic or connected with multiple populations. These findings indicate a strong similarity between optical and NIR metallicity scales in spite of the difference in the experimental equipment, data analysis, and in the adopted spectroscopic diagnostics. Based on spectra collected with the WINERED spectrograph available as a visitor instrument at the ESO New Technology Telescope (NTT), La Silla, Chile (ESO Proposal: 098.D-0878(A), PI: G. Bono).

  8. SPECIES RICHNESS AND BIODIVERSITY CONSERVATION PRIORITIES IN BRITISH COLUMBIA

    Science.gov (United States)

    Patterns in the geographic distribution of seven species groups were used to identify important areas for conservation in British Columbia, Canada. Potential priority sites for conservation were determined using an integer programming algorithm that maximized the number of speci...

  9. Canopy cover negatively affects arboreal ant species richness in a tropical open habitat

    Directory of Open Access Journals (Sweden)

    A. C. M. Queiroz

    Full Text Available Abstract We tested the hypothesis of a negative relationship between vegetation characteristics and ant species richness in a Brazilian open vegetation habitat, called candeial. We set up arboreal pitfalls to sample arboreal ants and measured the following environmental variables, which were used as surrogate of environmental heterogeneity: tree richness, tree density, tree height, circumference at the base of the plants, and canopy cover. Only canopy cover had a negative effect on the arboreal ant species richness. Vegetation characteristics and plant species composition are probably homogeneous in candeial, which explains the lack of relationship between other environmental variables and ant richness. Open vegetation habitats harbor a large number of opportunistic and generalist species, besides specialist ants from habitats with high temperatures. An increase in canopy cover decreases sunlight incidence and may cause local microclimatic differences, which negatively affect the species richness of specialist ants from open areas. Canopy cover regulates the richness of arboreal ants in open areas, since only few ant species are able to colonize sites with dense vegetation; most species are present in sites with high temperature and luminosity. Within open vegetation habitats the relationship between vegetation characteristics and species richness seems to be the opposite from closed vegetation areas, like forests.

  10. Predicting continental-scale patterns of bird species richness with spatially explicit models

    DEFF Research Database (Denmark)

    Rahbek, Carsten; Gotelli, Nicholas J; Colwell, Robert K

    2007-01-01

    the extraordinary diversity of avian species in the montane tropics, the most species-rich region on Earth. Our findings imply that correlative climatic models substantially underestimate the importance of historical factors and small-scale niche-driven assembly processes in shaping contemporary species-richness......The causes of global variation in species richness have been debated for nearly two centuries with no clear resolution in sight. Competing hypotheses have typically been evaluated with correlative models that do not explicitly incorporate the mechanisms responsible for biotic diversity gradients....... Here, we employ a fundamentally different approach that uses spatially explicit Monte Carlo models of the placement of cohesive geographical ranges in an environmentally heterogeneous landscape. These models predict species richness of endemic South American birds (2248 species) measured...

  11. Effects of habitat and landscape characteristics on medium and large mammal species richness and composition in northern Uruguay

    Directory of Open Access Journals (Sweden)

    María José Andrade-Núñez

    2010-01-01

    Full Text Available The increasing world population and demand for food and other products has accelerated the conversion of natural habitats into agricultural lands, plantations and urban areas. Changes in habitat and landscape characteristics due to land-use change can have a significant effect on species presence, abundance, and distribution. Multi-scale approaches have been used to determine the proper spatial scales at which species and communities are responding to habitat transformation. In this context, we evaluated medium and large mammal species richness and composition in gallery forest (n = 10, grassland (n = 10, and exotic tree plantation (n = 10 in a region where grasslands have been converted into exotic tree plantations. We quantified mammal species richness and composition with camera traps and track surveys. The composition of the mammal community was related with local habitat variables, and landscape variables measured at seven spatial scales. We found 14 mammal species in forest, 11 species in plantation, and 7 mammal species in grassland. Two species are exotics, the wild boar Sus scrofa Linnaeus, 1758 and the European hare Lepus europaeus Pallas, 1778. The most common species are the crab-eating fox Cerdocyon thous Linnaeus, 1766, the nine-banded armadillo Dasypus novemcinctus Linnaeus, 1758 and the gray brocket deer Mazama gouazoubira G. Fischer, 1814 which are generalist species. Our results showed significant differences in mammal species richness and composition among the three habitat types. Plantations can have positive and negative effects on the presence of species restricted to grasslands. Positive effects are reflected in a wider local distribution of some forest species that rarely use grassland. The most important habitat and landscape variables that influenced mammal species richness and composition were vertical structure index, canopy cover, tree species diversity, percentage of grass, and the percentage of forest and grassland

  12. Using species abundance distribution models and diversity indices for biogeographical analyses

    Science.gov (United States)

    Fattorini, Simone; Rigal, François; Cardoso, Pedro; Borges, Paulo A. V.

    2016-01-01

    We examine whether Species Abundance Distribution models (SADs) and diversity indices can describe how species colonization status influences species community assembly on oceanic islands. Our hypothesis is that, because of the lack of source-sink dynamics at the archipelago scale, Single Island Endemics (SIEs), i.e. endemic species restricted to only one island, should be represented by few rare species and consequently have abundance patterns that differ from those of more widespread species. To test our hypothesis, we used arthropod data from the Azorean archipelago (North Atlantic). We divided the species into three colonization categories: SIEs, archipelagic endemics (AZEs, present in at least two islands) and native non-endemics (NATs). For each category, we modelled rank-abundance plots using both the geometric series and the Gambin model, a measure of distributional amplitude. We also calculated Shannon entropy and Buzas and Gibson's evenness. We show that the slopes of the regression lines modelling SADs were significantly higher for SIEs, which indicates a relative predominance of a few highly abundant species and a lack of rare species, which also depresses diversity indices. This may be a consequence of two factors: (i) some forest specialist SIEs may be at advantage over other, less adapted species; (ii) the entire populations of SIEs are by definition concentrated on a single island, without possibility for inter-island source-sink dynamics; hence all populations must have a minimum number of individuals to survive natural, often unpredictable, fluctuations. These findings are supported by higher values of the α parameter of the Gambin mode for SIEs. In contrast, AZEs and NATs had lower regression slopes, lower α but higher diversity indices, resulting from their widespread distribution over several islands. We conclude that these differences in the SAD models and diversity indices demonstrate that the study of these metrics is useful for

  13. Species richness of arbuscular mycorrhizal fungi: associations with grassland plant richness and biomass

    Czech Academy of Sciences Publication Activity Database

    Hiiesalu, Inga; Pärtel, M.; Davison, J.; Gerhold, P.; Metsis, M.; Moora, M.; Öpik, M.; Vasar, M.; Zobel, M.; Wilson, S. D.

    2014-01-01

    Roč. 203, č. 1 (2014), s. 233-244 ISSN 1469-8137 R&D Projects: GA MŠk EE2.3.30.0048 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : belowground plant richness * diversity * productivity Subject RIV: EH - Ecology, Behaviour Impact factor: 6.545, year: 2013

  14. Effects of spatial heterogeneity on butterfly species richness in Rocky Mountain National Park, CO, USA

    Science.gov (United States)

    Kumar, S.; Simonson, S.E.; Stohlgren, T.J.

    2009-01-01

    We investigated butterfly responses to plot-level characteristics (plant species richness, vegetation height, and range in NDVI [normalized difference vegetation index]) and spatial heterogeneity in topography and landscape patterns (composition and configuration) at multiple spatial scales. Stratified random sampling was used to collect data on butterfly species richness from seventy-six 20 ?? 50 m plots. The plant species richness and average vegetation height data were collected from 76 modified-Whittaker plots overlaid on 76 butterfly plots. Spatial heterogeneity around sample plots was quantified by measuring topographic variables and landscape metrics at eight spatial extents (radii of 300, 600 to 2,400 m). The number of butterfly species recorded was strongly positively correlated with plant species richness, proportion of shrubland and mean patch size of shrubland. Patterns in butterfly species richness were negatively correlated with other variables including mean patch size, average vegetation height, elevation, and range in NDVI. The best predictive model selected using Akaike's Information Criterion corrected for small sample size (AICc), explained 62% of the variation in butterfly species richness at the 2,100 m spatial extent. Average vegetation height and mean patch size were among the best predictors of butterfly species richness. The models that included plot-level information and topographic variables explained relatively less variation in butterfly species richness, and were improved significantly after including landscape metrics. Our results suggest that spatial heterogeneity greatly influences patterns in butterfly species richness, and that it should be explicitly considered in conservation and management actions. ?? 2008 Springer Science+Business Media B.V.

  15. Species associations in a species-rich subtropical forest were not well-explained by stochastic geometry of biodiversity.

    Directory of Open Access Journals (Sweden)

    Qinggang Wang

    Full Text Available The stochastic dilution hypothesis has been proposed to explain species coexistence in species-rich communities. The relative importance of the stochastic dilution effects with respect to other effects such as competition and habitat filtering required to be tested. In this study, using data from a 25-ha species-rich subtropical forest plot with a strong topographic structure at Badagongshan in central China, we analyzed overall species associations and fine-scale species interactions between 2,550 species pairs. The result showed that: (1 the proportion of segregation in overall species association analysis at 2 m neighborhood in this plot followed the prediction of the stochastic dilution hypothesis that segregations should decrease with species richness but that at 10 m neighborhood was higher than the prediction. (2 The proportion of no association type was lower than the expectation of stochastic dilution hypothesis. (3 Fine-scale species interaction analyses using Heterogeneous Poisson processes as null models revealed a high proportion (47% of significant species effects. However, the assumption of separation of scale of this method was not fully met in this plot with a strong fine-scale topographic structure. We also found that for species within the same families, fine-scale positive species interactions occurred more frequently and negative ones occurred less frequently than expected by chance. These results suggested effects of environmental filtering other than species interaction in this forest. (4 We also found that arbor species showed a much higher proportion of significant fine-scale species interactions (66% than shrub species (18%. We concluded that the stochastic dilution hypothesis only be partly supported and environmental filtering left discernible spatial signals in the spatial associations between species in this species-rich subtropical forest with a strong topographic structure.

  16. Species associations in a species-rich subtropical forest were not well-explained by stochastic geometry of biodiversity.

    Science.gov (United States)

    Wang, Qinggang; Bao, Dachuan; Guo, Yili; Lu, Junmeng; Lu, Zhijun; Xu, Yaozhan; Zhang, Kuihan; Liu, Haibo; Meng, Hongjie; Jiang, Mingxi; Qiao, Xiujuan; Huang, Handong

    2014-01-01

    The stochastic dilution hypothesis has been proposed to explain species coexistence in species-rich communities. The relative importance of the stochastic dilution effects with respect to other effects such as competition and habitat filtering required to be tested. In this study, using data from a 25-ha species-rich subtropical forest plot with a strong topographic structure at Badagongshan in central China, we analyzed overall species associations and fine-scale species interactions between 2,550 species pairs. The result showed that: (1) the proportion of segregation in overall species association analysis at 2 m neighborhood in this plot followed the prediction of the stochastic dilution hypothesis that segregations should decrease with species richness but that at 10 m neighborhood was higher than the prediction. (2) The proportion of no association type was lower than the expectation of stochastic dilution hypothesis. (3) Fine-scale species interaction analyses using Heterogeneous Poisson processes as null models revealed a high proportion (47%) of significant species effects. However, the assumption of separation of scale of this method was not fully met in this plot with a strong fine-scale topographic structure. We also found that for species within the same families, fine-scale positive species interactions occurred more frequently and negative ones occurred less frequently than expected by chance. These results suggested effects of environmental filtering other than species interaction in this forest. (4) We also found that arbor species showed a much higher proportion of significant fine-scale species interactions (66%) than shrub species (18%). We concluded that the stochastic dilution hypothesis only be partly supported and environmental filtering left discernible spatial signals in the spatial associations between species in this species-rich subtropical forest with a strong topographic structure.

  17. Species Richness, Community Organization, and Spatiotemporal Distribution of Earthworms in the Pineapple Agroecosystems of Tripura, India

    Directory of Open Access Journals (Sweden)

    Animesh Dey

    2016-01-01

    Full Text Available The impact that plant communities may have on underground faunal diversity is unclear. Therefore, understanding the links between plants and organisms is of major interest. Earthworm population dynamics were studied in the pineapple agroecosystems of Tripura to evaluate the impact of monoculture plantation on earthworm communities. A total of thirteen earthworm species belonging to four families and five genera were collected from different sampling sites. Application of sample-based rarefaction curve and nonparametric richness estimators reveal 90–95% completeness of sampling. Earthworm community of pineapple agroecosystems was dominated by endogeic earthworms and Drawida assamensis was the dominant species with respect to its density, biomass, and relative abundance. Vertical distribution of earthworms was greatly influenced by seasonal variations. Population density and biomass of earthworms peaked during monsoon and postmonsoon period, respectively. Overall density and biomass of earthworms were in increasing trend with an increase in plantation age and were highest in the 30–35-year-old plantation. Significant decrease in the Shannon diversity and evenness index and increase in Simpson’s dominance and spatial aggregation index with an increase in the age of pineapple plantation were recorded. Soil temperature and soil moisture were identified as the most potent regulators of earthworm distribution in the pineapple plantation.

  18. Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

    Science.gov (United States)

    Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

    2015-03-15

    Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Evaluation of species richness estimators based on quantitative performance measures and sensitivity to patchiness and sample grain size

    Science.gov (United States)

    Willie, Jacob; Petre, Charles-Albert; Tagg, Nikki; Lens, Luc

    2012-11-01

    Data from forest herbaceous plants in a site of known species richness in Cameroon were used to test the performance of rarefaction and eight species richness estimators (ACE, ICE, Chao1, Chao2, Jack1, Jack2, Bootstrap and MM). Bias, accuracy, precision and sensitivity to patchiness and sample grain size were the evaluation criteria. An evaluation of the effects of sampling effort and patchiness on diversity estimation is also provided. Stems were identified and counted in linear series of 1-m2 contiguous square plots distributed in six habitat types. Initially, 500 plots were sampled in each habitat type. The sampling process was monitored using rarefaction and a set of richness estimator curves. Curves from the first dataset suggested adequate sampling in riparian forest only. Additional plots ranging from 523 to 2143 were subsequently added in the undersampled habitats until most of the curves stabilized. Jack1 and ICE, the non-parametric richness estimators, performed better, being more accurate and less sensitive to patchiness and sample grain size, and significantly reducing biases that could not be detected by rarefaction and other estimators. This study confirms the usefulness of non-parametric incidence-based estimators, and recommends Jack1 or ICE alongside rarefaction while describing taxon richness and comparing results across areas sampled using similar or different grain sizes. As patchiness varied across habitat types, accurate estimations of diversity did not require the same number of plots. The number of samples needed to fully capture diversity is not necessarily the same across habitats, and can only be known when taxon sampling curves have indicated adequate sampling. Differences in observed species richness between habitats were generally due to differences in patchiness, except between two habitats where they resulted from differences in abundance. We suggest that communities should first be sampled thoroughly using appropriate taxon sampling

  20. Estimation of the species richness of fish parasite fauna: an ecological approach

    Directory of Open Access Journals (Sweden)

    Ieshko Evgeny Pavlovich

    2012-12-01

    Full Text Available We studied the biological diversity of the parasite fauna in pike from four habitats found in northern lakes of Karelia. The curves of the expected species richness versus sampling effort (the number of examined specimens dependency were plotted. A universal approach to the description of the new species replenishment dynamics is proposed – including finding (through combinatorial analysis the median value between the fastest and the slowest paths of the species richness growth followed by approximation using logistic function . Our analysis showed that the leading ecological factors controlling the formation of the parasite species richness in a specific waterbody are the richness of infracommunities and the age composition of the host sample. The sample of 15 host specimens contains at least 80% of all species in the parasite community.

  1. Local versus landscape-scale effects of anthropogenic land-use on forest species richness

    Science.gov (United States)

    Buffa, G.; Del Vecchio, S.; Fantinato, E.; Milano, V.

    2018-01-01

    The study investigated the effects of human-induced landscape patterns on species richness in forests. For 80 plots of fixed size, we measured human disturbance (categorized as urban/industrial and agricultural land areas), at 'local' and 'landscape' scale (500 m and 2500 m radius from each plot, respectively), the distance from the forest edge, and the size and shape of the woody patch. By using GLM, we analyzed the effects of disturbance and patch-based measures on both total species richness and the richness of a group of specialist species (i.e. the 'ancient forest species'), representing more specific forest features. Patterns of local species richness were sensitive to the structure and composition of the surrounding landscape. Among the landscape components taken into account, urban/industrial land areas turned out as the most threatening factor for both total species richness and the richness of the ancient forest species. However, the best models evidenced a different intensity of the response to the same disturbance category as well as a different pool of significant variables for the two groups of species. The use of groups of species, such as the ancient forest species pool, that are functionally related and have similar ecological requirements, may represent an effective solution for monitoring forest dynamics under the effects of external factors. The approach of relating local assessment of species richness, and in particular of the ancient forest species pool, to land-use patterns may play an important role for the science-policy interface by supporting and strengthening conservation and regional planning decision making.

  2. Combining geodiversity with climate and topography to account for threatened species richness.

    Science.gov (United States)

    Tukiainen, Helena; Bailey, Joseph J; Field, Richard; Kangas, Katja; Hjort, Jan

    2017-04-01

    Understanding threatened species diversity is important for long-term conservation planning. Geodiversity-the diversity of Earth surface materials, forms, and processes-may be a useful biodiversity surrogate for conservation and have conservation value itself. Geodiversity and species richness relationships have been demonstrated; establishing whether geodiversity relates to threatened species' diversity and distribution pattern is a logical next step for conservation. We used 4 geodiversity variables (rock-type and soil-type richness, geomorphological diversity, and hydrological feature diversity) and 4 climatic and topographic variables to model threatened species diversity across 31 of Finland's national parks. We also analyzed rarity-weighted richness (a measure of site complementarity) of threatened vascular plants, fungi, bryophytes, and all species combined. Our 1-km 2 resolution data set included 271 threatened species from 16 major taxa. We modeled threatened species richness (raw and rarity weighted) with boosted regression trees. Climatic variables, especially the annual temperature sum above 5 °C, dominated our models, which is consistent with the critical role of temperature in this boreal environment. Geodiversity added significant explanatory power. High geodiversity values were consistently associated with high threatened species richness across taxa. The combined effect of geodiversity variables was even more pronounced in the rarity-weighted richness analyses (except for fungi) than in those for species richness. Geodiversity measures correlated most strongly with species richness (raw and rarity weighted) of threatened vascular plants and bryophytes and were weakest for molluscs, lichens, and mammals. Although simple measures of topography improve biodiversity modeling, our results suggest that geodiversity data relating to geology, landforms, and hydrology are also worth including. This reinforces recent arguments that conserving nature's stage

  3. Estimating Lion Abundance using N-mixture Models for Social Species.

    Science.gov (United States)

    Belant, Jerrold L; Bled, Florent; Wilton, Clay M; Fyumagwa, Robert; Mwampeta, Stanslaus B; Beyer, Dean E

    2016-10-27

    Declining populations of large carnivores worldwide, and the complexities of managing human-carnivore conflicts, require accurate population estimates of large carnivores to promote their long-term persistence through well-informed management We used N-mixture models to estimate lion (Panthera leo) abundance from call-in and track surveys in southeastern Serengeti National Park, Tanzania. Because of potential habituation to broadcasted calls and social behavior, we developed a hierarchical observation process within the N-mixture model conditioning lion detectability on their group response to call-ins and individual detection probabilities. We estimated 270 lions (95% credible interval = 170-551) using call-ins but were unable to estimate lion abundance from track data. We found a weak negative relationship between predicted track density and predicted lion abundance from the call-in surveys. Luminosity was negatively correlated with individual detection probability during call-in surveys. Lion abundance and track density were influenced by landcover, but direction of the corresponding effects were undetermined. N-mixture models allowed us to incorporate multiple parameters (e.g., landcover, luminosity, observer effect) influencing lion abundance and probability of detection directly into abundance estimates. We suggest that N-mixture models employing a hierarchical observation process can be used to estimate abundance of other social, herding, and grouping species.

  4. Some peculiarities of fish abundance, species and sizes distribution, and spacing

    International Nuclear Information System (INIS)

    Astrauskas, A.; Bernotas, E.; Jovaisha, R.

    1995-01-01

    During the construction and exploitation process of Ignalina NPP the abundance of fishes has dropped, and especially stenothermic species (smelt and vendace). The general increase of fish abundance is observed in recent years (1992-1994). This is linked with changes of fish species and their adaptation to the new environmental conditions. Now the partial renovation of vendace abundance is observed, too. It is a result of free feeding recess coming out as the smelt dramatically decreased. Before now the ecosystem of the lake is greatly disbalanced due to antropogenetic impact of the NPP. It's partial stabilisation (but on the essentially high level) is possible only in some generations of fish living in the lake. (author). 18 refs., 1 tab., 11 figs

  5. Earthworm abundance and species composition in abandoned tropical croplands: comparisons of tree plantations and secondary forests.

    Science.gov (United States)

    G. Gonzalez; X. Zou; S. Borges

    1996-01-01

    We compared patterns of earthworms abundance and species composition in tree plantation and secondary forest of Puerto Rico. Tree plantations included pine (Pinus caribea Morelet) and mahogany (Swietenia macrophylla King) established in the 1930's; 1960's; and 1970's; secondary forests were naturally regenerated in areas adjacent to these plantations. We...

  6. Linking nitrogen partitioning and species abundance to invasion resistance in the Great Basin

    Science.gov (United States)

    J. J. James; K. W. Davies; R. L. Sheley; Z. T. Aanderud

    2008-01-01

    Resource partitioning has been suggested as an important mechanism of invasion resistance. The relative importance of resource partitioning for invasion resistance, however, may depend on how species abundance is distributed in the plant community. This study had two objectives. First, we quantified the degree to which one resource, nitrogen (N), is partitioned by time...

  7. A robust and accurate binning algorithm for metagenomic sequences with arbitrary species abundance ratio.

    Science.gov (United States)

    Leung, Henry C M; Yiu, S M; Yang, Bin; Peng, Yu; Wang, Yi; Liu, Zhihua; Chen, Jingchi; Qin, Junjie; Li, Ruiqiang; Chin, Francis Y L

    2011-06-01

    With the rapid development of next-generation sequencing techniques, metagenomics, also known as environmental genomics, has emerged as an exciting research area that enables us to analyze the microbial environment in which we live. An important step for metagenomic data analysis is the identification and taxonomic characterization of DNA fragments (reads or contigs) resulting from sequencing a sample of mixed species. This step is referred to as 'binning'. Binning algorithms that are based on sequence similarity and sequence composition markers rely heavily on the reference genomes of known microorganisms or phylogenetic markers. Due to the limited availability of reference genomes and the bias and low availability of markers, these algorithms may not be applicable in all cases. Unsupervised binning algorithms which can handle fragments from unknown species provide an alternative approach. However, existing unsupervised binning algorithms only work on datasets either with balanced species abundance ratios or rather different abundance ratios, but not both. In this article, we present MetaCluster 3.0, an integrated binning method based on the unsupervised top--down separation and bottom--up merging strategy, which can bin metagenomic fragments of species with very balanced abundance ratios (say 1:1) to very different abundance ratios (e.g. 1:24) with consistently higher accuracy than existing methods. MetaCluster 3.0 can be downloaded at http://i.cs.hku.hk/~alse/MetaCluster/.

  8. impact of physicochemical factors on zooplankton species richness

    African Journals Online (AJOL)

    DR. AMINU

    This study revealed that physicochemical fluctuations was negative impact on the zooplankton species ... of convergence of wastewater streams, of which Jakara River carries ..... Discharge on Physicochemical Parameters and Some Heavy ...

  9. Plant Size as Determinant of Species Richness of Herbivores, Natural Enemies and Pollinators across 21 Brassicaceae Species.

    Directory of Open Access Journals (Sweden)

    Hella Schlinkert

    Full Text Available Large plants are often more conspicuous and more attractive for associated animals than small plants, e.g. due to their wider range of resources. Therefore, plant size can positively affect species richness of associated animals, as shown for single groups of herbivores, but studies usually consider intraspecific size differences of plants in unstandardised environments. As comprehensive tests of interspecific plant size differences under standardised conditions are missing so far, we investigated effects of plant size on species richness of all associated arthropods using a common garden experiment with 21 Brassicaceae species covering a broad interspecific plant size gradient from 10 to 130 cm height. We recorded plant associated ecto- and endophagous herbivores, their natural enemies and pollinators on and in each aboveground plant organ, i.e. flowers, fruits, leaves and stems. Plant size (measured as height from the ground, the number of different plant organ entities and their biomass were assessed. Increasing plant size led to increased species richness of associated herbivores, natural enemies and pollinating insects. This pattern was found for ectophagous and endophagous herbivores, their natural enemies, as well as for herbivores associated with leaves and fruits and their natural enemies, independently of the additional positive effects of resource availability (i.e. organ biomass or number of entities and, regarding natural enemies, herbivore species richness. We found a lower R2 for pollinators compared to herbivores and natural enemies, probably caused by the high importance of flower characteristics for pollinator species richness besides plant size. Overall, the increase in plant height from 10 to 130 cm led to a 2.7-fold increase in predicted total arthropod species richness. In conclusion, plant size is a comprehensive driver of species richness of the plant associated arthropods, including pollinators, herbivores and their

  10. Community analysis of the abundance and diversity of biting midge species (Diptera: Ceratopogonidae) in three European countries at different latitudes.

    Science.gov (United States)

    Möhlmann, Tim W R; Wennergren, Uno; Tälle, Malin; Favia, Guido; Damiani, Claudia; Bracchetti, Luca; Takken, Willem; Koenraadt, Constantianus J M

    2018-03-27

    The outbreaks of bluetongue and Schmallenberg disease in Europe have increased efforts to understand the ecology of Culicoides biting midges and their role in pathogen transmission. However, most studies have focused on a specific habitat, region, or country. To facilitate wider comparisons, and to obtain a better understanding of the spread of disease through Europe, the present study focused on monitoring biting midge species diversity in three different habitat types and three countries across Europe. Biting midges were trapped using Onderstepoort Veterinary Institute light traps at a total of 27 locations in Sweden, the Netherlands and Italy, comprising farm, peri-urban and wetland habitats. From July 2014 to June 2015 all locations were sampled monthly, except for during the winter months. Trapped midges were counted and identified morphologically. Indices on species richness, evenness and diversity were calculated. Community compositions were analysed using non-metric multidimensional scaling (NMDS) techniques. A total of 50,085 female midges were trapped during 442 collection nights. More than 88% of these belonged to the Obsoletus group. The highest midge diversity was found in Sweden, while species richness was highest in the Netherlands, and most specimens were trapped in Italy. For habitats within countries, diversity of the trapped midges was lowest for farms in all countries. Differences in biting midge species communities were more distinct across the three countries than the three habitat types. A core midge community could be identified, in which the Obsoletus group was the most abundant. Variations in vector communities across countries imply different patterns of disease spread throughout Europe. How specific species and their associated communities affect disease risk is still unclear. Our results emphasize the importance of midge diversity data at community level, how this differs across large geographic range within Europe, and its implications

  11. Resource stoichiometry and availability modulate species richness and biomass of tropical litter macro-invertebrates.

    Science.gov (United States)

    Jochum, Malte; Barnes, Andrew D; Weigelt, Patrick; Ott, David; Rembold, Katja; Farajallah, Achmad; Brose, Ulrich

    2017-09-01

    High biodiversity and biomass of soil communities are crucial for litter decomposition in terrestrial ecosystems such as tropical forests. However, the leaf litter that these communities consume is of particularly poor quality as indicated by elemental stoichiometry. The impact of resource quantity, quality and other habitat parameters on species richness and biomass of consumer communities is often studied in isolation, although much can be learned from simultaneously studying both community characteristics. Using a dataset of 780 macro-invertebrate consumer species across 32 sites in tropical lowland rain forest and agricultural systems on Sumatra, Indonesia, we investigated the effects of basal resource stoichiometry (C:X ratios of N, P, K, Ca, Mg, Na, S in local leaf litter), litter mass (basal resource quantity and habitat space), plant species richness (surrogate for litter habitat heterogeneity), and soil pH (acidity) on consumer species richness and biomass across different consumer groups (i.e. 3 feeding guilds and 10 selected taxonomic groups). In order to distinguish the most important predictors of consumer species richness and biomass, we applied a standardised model averaging approach investigating the effects of basal resource stoichiometry, litter mass, plant species richness and soil pH on both consumer community characteristics. This standardised approach enabled us to identify differences and similarities in the magnitude and importance of such effects on consumer species richness and biomass. Across consumer groups, we found litter mass to be the most important predictor of both species richness and biomass. Resource stoichiometry had a more pronounced impact on consumer species richness than on their biomass. As expected, taxonomic groups differed in which resource and habitat parameters (basal resource stoichiometry, litter mass, plant species richness and pH) were most important for modulating their community characteristics. The importance

  12. Bat species richness and activity over an elevation gradient in mediterranean shrublands of Crete

    Directory of Open Access Journals (Sweden)

    Panagiotis Georgiakakis

    2010-08-01

    Full Text Available Abstract
    The effect of elevation on bat species richness and activity was investigated in shrublands of central Crete (Greece using broad-band acoustic surveys. Recordings of echolocation calls were made in 15 transects equally distributed in three distinct elevation zones (500, 1000 and 1500 m a.s.l. during spring and autumn 2007-2008. Time-expanded calls were subsequently identified with the use of quadratic discriminant functions.
    Out of 13 species recorded, Hypsugo savii, Pipistrellus kuhlii and Tadarida teniotis were the most common and abundant. Many Rhinolophus hipposideros were also recorded in all elevation zones. Thirteen species were recorded in the lower elevation zone, 7 species in the mid one and 8 species in the 1500 m a.s.l. sites. Species richness, the number of bat passes of the most abundant species, as well as the total number of bat passes were not significantly affected by elevation. In spring both species richness and bat activity were higher than in autumn, although the corresponding difference in temperature was not significant.
    The high variability in both bat activity and the number of species found per transect in each elevation zone probably depended on the presence of other habitat types in the close vicinity, while roost availability and location might also have played an important role.
    We suggest that the ability of bats to perform regular movements along the elevational gradient has to be taken in account when assessing elevational patterns in bat diversity and activity. The geology of the study area is also of considerable importance through its effect on foraging and roosting opportunities for bats.

    Riassunto
    Ricchezza specifica e attività dei chirotteri lungo un gradiente altitudinale nella macchia mediterranea di Creta
    L’effetto della quota su ricchezza in specie e

  13. Recent Changes in Tree Species Abundance: Patterns, Trends, and Drivers Across Northeastern US Forests

    Science.gov (United States)

    Gudex-Cross, D.; Pontius, J.; Adams, A.

    2017-12-01

    Monitoring trends in the abundance and distribution of tree species is essential to understanding potential impacts of climate change on forested ecosystems. Related studies to date have largely focused on modeling distributional shifts according to future climate scenarios or used field inventory data to examine compositional changes across broader landscapes. Here, we leverage a novel remote sensing technique that utilizes field data, multitemporal Landsat imagery, and spectral unmixing to model regional changes in the abundance (percent basal area) of key northeastern US species over a 30-year period (1985-2015). We examine patterns in how species abundance has changed, as well as their relationship with climate, landscape, and soil characteristics using spatial regression models. Results show significant declines in overall abundance for sugar maple ( 8.6% 30-yr loss), eastern hemlock ( 7.8% 30-yr loss), balsam fir ( 5.0% 30-yr loss), and red spruce ( 3.8% total 30-yr loss). Species that saw significant increasing abundance include American beech ( 7.0% 30-yr gain) and red maple ( 2.5% 30-yr gain). However, these changes were not consistent across the landscape. For example, red spruce is increasing at upper elevations with concurrent losses in balsam fir and birch species. Similarly, sugar maple decreases are concentrated at lower elevations, likely due to increases in American beech. Various abiotic factors were significantly associated with changes in species composition including landscape position (e.g. longitude, elevation, and heat load index) and ecologically-relevant climate variables (e.g. growing season precipitation and annual temperature range). Interestingly, there was a stronger relationship in abundance changes across longitudes, rather than latitudes or elevations as predicted in modeled species migration scenarios.These results indicate that the dominant composition of northeastern forests is changing in ways that run counter to accepted

  14. Influence of Trap Height and Bait Type on Abundance and Species Diversity of Cerambycid Beetles Captured in Forests of East-Central Illinois.

    Science.gov (United States)

    Schmeelk, Thomas C; Millar, Jocelyn G; Hanks, Lawrence M

    2016-08-01

    We assessed how height of panel traps above the forest floor, and the type of trap bait used, influenced the abundance and diversity of cerambycid beetles caught in forested areas of east-central Illinois. Panel traps were suspended from branches of hardwood trees at three heights above the ground: understory (∼1.5 m), lower canopy (∼6 m), and midcanopy (∼12 m). Traps were baited with either a multispecies blend of synthesized cerambycid pheromones or a fermenting bait mixture. Traps captured a total of 848 beetles of 50 species in the cerambycid subfamilies Cerambycinae, Lamiinae, Lepturinae, and Parandrinae, and one species in the closely related family Disteniidae. The species caught in highest numbers was the cerambycine Anelaphus pumilus (Newman), represented by 349 specimens. The 17 most abundant species (mean ± 1 SD: 45 ± 80 specimens per species) included 12 cerambycine and five lamiine species. Of these most abundant species, 13 (77%) were attracted to traps baited with the pheromone blend. Only the cerambycine Eburia quadrigeminata (Say) was attracted by the fermenting bait. Three species were captured primarily in understory traps, and another five species primarily in midcanopy traps. Variation among cerambycid species in their vertical distribution in forests accounted for similar overall abundances and species richness across trap height treatments. These findings suggest that trapping surveys of native communities of cerambycids, and quarantine surveillance for newly introduced exotic species, would be optimized by including a variety of trap baits and distributing traps across vertical strata of forests. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Species richness and the temporal stability of biomass production: a new analysis of recent biodiversity experiments

    NARCIS (Netherlands)

    Gross, K.; Cardinale, B.J.; Fox, J.W.; Gonzalez, A.; Loreau, M.; Polley, H.W.; Reich, P.B.; Ruijven, van J.

    2013-01-01

    The relationship between biological diversity and ecological stability has fascinated ecologists for decades. Determining the generality of this relationship, and discovering the mechanisms that underlie it, are vitally important for ecosystem management. Here, we investigate how species richness

  16. Simkin et al. 2016 PNAS data on herbaceous species richness and associated plot and covariate information

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes the geographic location (lat/lon) for 15,136 plots, as well as the herbaceous species richness, climate, soil pH, and other variables related...

  17. Scleractinian species richness for Florida Keys National Marine Sanctuary from 1996-2012 (NODC Accession 0123059)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains records of scleractinian species richness compiled from multiple sources. These are: CREMP, SCREAM, AGRRA, and FRRP CREMP: Coral Reef...

  18. Explaining the species richness of birds along a subtropical elevational gradient in the Hengduan Mountains

    DEFF Research Database (Denmark)

    Wu, Yongjie; Colwell, Robert K.; Rahbek, Carsten

    2013-01-01

    AimTo document the species richness pattern of birds in the Hengduan Mountains and to understand its causes. LocationHengduan Mountains, China. MethodsSpecies richness of 738 breeding bird species was calculated for each 100-m elevational band along a gradient from 100 to 6000m a.s.l. Climate data...... were compiled based on monthly records from 182 meteorological stations in the Hengduan Mountains from 1959 to 2004. We calculated the planimetric area, predicted richness under geometric constraints, three-year average NDVI (normalized difference vegetation index) and EVI (enhanced vegetation index...... that climatic and energy factors correlate well with the richness pattern of birds, and that on the surveyed subtropical mountain, the elevational bands with highest seasonality harbour fewer species than areas with less seasonal variation in temperature. The results, however, vary somewhat among taxonomic...

  19. Species richness pattern along altitudinal gradient in Central European beech forests

    Czech Academy of Sciences Publication Activity Database

    Hrivnák, R.; Gömöry, D.; Slezák, M.; Ujházy, K.; Hédl, Radim; Jarčuška, B.; Ujházyová, M.

    2014-01-01

    Roč. 49, č. 3 (2014), s. 425-441 ISSN 1211-9520 Institutional support: RVO:67985939 Keywords : altitude * beech-dominated forest * species richness Subject RIV: EF - Botanics Impact factor: 1.778, year: 2014

  20. Predicting spatial variations of tree species richness in tropical forests from high-resolution remote sensing.

    Science.gov (United States)

    Fricker, Geoffrey A; Wolf, Jeffrey A; Saatchi, Sassan S; Gillespie, Thomas W

    2015-10-01

    There is an increasing interest in identifying theories, empirical data sets, and remote-sensing metrics that can quantify tropical forest alpha diversity at a landscape scale. Quantifying patterns of tree species richness in the field is time consuming, especially in regions with over 100 tree species/ha. We examine species richness in a 50-ha plot in Barro Colorado Island in Panama and test if biophysical measurements of canopy reflectance from high-resolution satellite imagery and detailed vertical forest structure and topography from light detection and ranging (lidar) are associated with species richness across four tree size classes (>1, 1-10, >10, and >20 cm dbh) and three spatial scales (1, 0.25, and 0.04 ha). We use the 2010 tree inventory, including 204,757 individuals belonging to 301 species of freestanding woody plants or 166 ± 1.5 species/ha (mean ± SE), to compare with remote-sensing data. All remote-sensing metrics became less correlated with species richness as spatial resolution decreased from 1.0 ha to 0.04 ha and tree size increased from 1 cm to 20 cm dbh. When all stems with dbh > 1 cm in 1-ha plots were compared to remote-sensing metrics, standard deviation in canopy reflectance explained 13% of the variance in species richness. The standard deviations of canopy height and the topographic wetness index (TWI) derived from lidar were the best metrics to explain the spatial variance in species richness (15% and 24%, respectively). Using multiple regression models, we made predictions of species richness across Barro Colorado Island (BCI) at the 1-ha spatial scale for different tree size classes. We predicted variation in tree species richness among all plants (adjusted r² = 0.35) and trees with dbh > 10 cm (adjusted r² = 0.25). However, the best model results were for understory trees and shrubs (dbh 1-10 cm) (adjusted r² = 0.52) that comprise the majority of species richness in tropical forests. Our results indicate that high

  1. Species richness and trophic diversity increase decomposition in a co-evolved food web.

    Directory of Open Access Journals (Sweden)

    Benjamin Baiser

    Full Text Available Ecological communities show great variation in species richness, composition and food web structure across similar and diverse ecosystems. Knowledge of how this biodiversity relates to ecosystem functioning is important for understanding the maintenance of diversity and the potential effects of species losses and gains on ecosystems. While research often focuses on how variation in species richness influences ecosystem processes, assessing species richness in a food web context can provide further insight into the relationship between diversity and ecosystem functioning and elucidate potential mechanisms underpinning this relationship. Here, we assessed how species richness and trophic diversity affect decomposition rates in a complete aquatic food web: the five trophic level web that occurs within water-filled leaves of the northern pitcher plant, Sarracenia purpurea. We identified a trophic cascade in which top-predators--larvae of the pitcher-plant mosquito--indirectly increased bacterial decomposition by preying on bactivorous protozoa. Our data also revealed a facultative relationship in which larvae of the pitcher-plant midge increased bacterial decomposition by shredding detritus. These important interactions occur only in food webs with high trophic diversity, which in turn only occur in food webs with high species richness. We show that species richness and trophic diversity underlie strong linkages between food web structure and dynamics that influence ecosystem functioning. The importance of trophic diversity and species interactions in determining how biodiversity relates to ecosystem functioning suggests that simply focusing on species richness does not give a complete picture as to how ecosystems may change with the loss or gain of species.

  2. USING TAXONOMIC REVISION DATA TO ESTIMATE THE GLOBAL SPECIES RICHNESS AND CHARACTERISTICS OF UNDESCRIBED SPECIES OF DIVING BEETLES (COLEOPTERA: DYTISCIDAE

    Directory of Open Access Journals (Sweden)

    Viktor Nilsson-Örtman

    2010-06-01

    Full Text Available Many methods used for estimating species richness are either difficult to use on poorly known taxa or require input data that are laborious and expensive to collect. In this paper we apply a method which takes advantage of the carefully conducted tests of how the described diversity compares to real species richness that are inherent in taxonomic revisions. We analyze the quantitative outcome from such revisions with respect to body size, zoogeographical region and phylogenetic relationship. The best fitting model is used to predict the diversity of unrevised groups if these would have been subject to as rigorous species level hypothesis-testing as the revised groups. The sensitivity of the predictive model to single observations is estimated by bootstrapping over resampled subsets of the original data. The Dytiscidae is with its 4080 described species (end of May 2009 the most diverse group of aquatic beetles and have a world-wide distribution. Extensive taxonomic work has been carried out on the family but still the number of described species increases exponentially in most zoogeographical regions making many commonly used methods of estimation difficult to apply. We provide independent species richness estimates of subsamples for which species richness estimates can be reached through extrapolation and compare these to the species richness estimates obtained through the method using revision data. We estimate there to be 5405 species of dytiscids, a 1.32-fold increase over the present number of described species. The undescribed diversity is likely to be biased towards species with small body size from tropical regions outside of Africa.

  3. Intercropping With Fruit Trees Increases Population Abundance and Alters Species Composition of Spider Mites on Cotton.

    Science.gov (United States)

    Li, Haiqiang; Pan, Hongsheng; Wang, Dongmei; Liu, Bing; Liu, Jian; Zhang, Jianping; Lu, Yanhui

    2018-05-05

    With the recent increase in planting of fruit trees in southern Xinjiang, the intercropping of fruit trees and cotton has been widely adopted. From 2014 to 2016, a large-scale study was conducted in Aksu, an important agricultural area in southern Xinjiang, to compare the abundance and species composition of spider mites in cotton fields under jujube-cotton, apple-cotton, and cotton monocrop systems. The abundance of spider mites in cotton fields under both intercropping systems was generally higher than in the cotton monocrop. The species composition of spider mites also differed greatly between cotton intercropped with apple or jujube compared to the cotton monocrop. The relative proportion of Tetranychus truncates Ehara (Acari: Tetranychidae) in the species complex generally increased while that of another spider mite, Tetranychus dunhuangensis Wang (Acari: Tetranychidae), decreased under fruit tree-cotton systems. More attention should be paid to the monitoring and management of spider mites, especially T. truncates in this important region of China.

  4. Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species.

    Science.gov (United States)

    Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

    2014-02-01

    Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates.

  5. Species abundance distributions in neutral models with immigration or mutation and general lifetimes.

    Science.gov (United States)

    Lambert, Amaury

    2011-07-01

    We consider a general, neutral, dynamical model of biodiversity. Individuals have i.i.d. lifetime durations, which are not necessarily exponentially distributed, and each individual gives birth independently at constant rate λ. Thus, the population size is a homogeneous, binary Crump-Mode-Jagers process (which is not necessarily a Markov process). We assume that types are clonally inherited. We consider two classes of speciation models in this setting. In the immigration model, new individuals of an entirely new species singly enter the population at constant rate μ (e.g., from the mainland into the island). In the mutation model, each individual independently experiences point mutations in its germ line, at constant rate θ. We are interested in the species abundance distribution, i.e., in the numbers, denoted I(n)(k) in the immigration model and A(n)(k) in the mutation model, of species represented by k individuals, k = 1, 2, . . . , n, when there are n individuals in the total population. In the immigration model, we prove that the numbers (I(t)(k); k ≥ 1) of species represented by k individuals at time t, are independent Poisson variables with parameters as in Fisher's log-series. When conditioning on the total size of the population to equal n, this results in species abundance distributions given by Ewens' sampling formula. In particular, I(n)(k) converges as n → ∞ to a Poisson r.v. with mean γ/k, where γ : = μ/λ. In the mutation model, as n → ∞, we obtain the almost sure convergence of n (-1) A(n)(k) to a nonrandom explicit constant. In the case of a critical, linear birth-death process, this constant is given by Fisher's log-series, namely n(-1) A(n)(k) converges to α(k)/k, where α : = λ/(λ + θ). In both models, the abundances of the most abundant species are briefly discussed.

  6. Can temporal and spatial NDVI predict regional bird-species richness?

    Directory of Open Access Journals (Sweden)

    Sebastián Nieto

    2015-01-01

    Full Text Available Understanding the distribution of the species and its controls over biogeographic scales is still a major challenge in ecology. National Park Networks provide an opportunity to assess the relationship between ecosystem functioning and biodiversity in areas with low human impacts. We tested the productivity–biodiversity hypothesis which states that the number of species increases with the available energy, and the ​variability–biodiversity hypothesis which states that the number of species increases with the diversity of habitats. The available energy and habitat heterogeneity estimated by the normalized difference vegetation index (NDVI was shown as a good predictor of bird-species richness for a diverse set of biomes in previously published studies. However, there is not a universal relationship between NDVI and bird-species richness. Here we tested if the NDVI can predict bird species richness in areas with low human impact in Argentina. Using a dataset from the National Park Network of Argentina we found that the best predictor of bird species richness was the minimum value of NDVI per year which explained 75% of total variability. The inclusion of the spatial heterogeneity of NDVI improved the explanation power to 80%. Minimum NDVI was highly correlated with precipitation and winter temperature. Our analysis provides a tool for assessing bird-species richness at scales on which land-use planning practitioners make their decisions for Southern South America.

  7. Weed-Species Abundance and Diversity Indices in Relation to Tillage Systems and Fertilization

    Directory of Open Access Journals (Sweden)

    Ilias S. Travlos

    2018-04-01

    Full Text Available Weeds pose a major threat to world agriculture by reducing detrimentally crop yield and quality. However, at the same time, weeds are major interacting components of the agroecosystems. Abundance and diversity of weeds vary significantly among the several communities. In order to evaluate each community's structure and the interactions among them, several population indices are used as key tools. In parallel, various cultivation and land management strategies, such as tillage and fertilization, are commonly used in terms of integrated weed management. Estimating the response of weed species on those practices is crucial for both biodiversity maintenance and alternative weed control methods. Many experiments have confirmed the fundamental role of tillage intensity and nutrition supply in weed species' abundance and diversity. For instance, in some studies, the abundance of perennial weeds was doubled under reduced tillage intensity. In addition, higher values of Shannon-Weiner and Pielou indices were reported in the PK fertilization treatment compared to the control and NK fertilization treatments. The objective of this paper is to provide a brief overview of the key results of these experiments and summarize the part of the literature related to the effect of tillage systems and fertilization on weed species abundance and diversity. Such knowledge could contribute to the sound design and implementation of integrated weed management programs which in turn may lead to a decrease in the density of serious and noxious weeds and an increase in the overall balance of agroecosystems.

  8. Boolean analysis reveals systematic interactions among low-abundance species in the human gut microbiome.

    Directory of Open Access Journals (Sweden)

    Jens Christian Claussen

    2017-06-01

    Full Text Available The analysis of microbiome compositions in the human gut has gained increasing interest due to the broader availability of data and functional databases and substantial progress in data analysis methods, but also due to the high relevance of the microbiome in human health and disease. While most analyses infer interactions among highly abundant species, the large number of low-abundance species has received less attention. Here we present a novel analysis method based on Boolean operations applied to microbial co-occurrence patterns. We calibrate our approach with simulated data based on a dynamical Boolean network model from which we interpret the statistics of attractor states as a theoretical proxy for microbiome composition. We show that for given fractions of synergistic and competitive interactions in the model our Boolean abundance analysis can reliably detect these interactions. Analyzing a novel data set of 822 microbiome compositions of the human gut, we find a large number of highly significant synergistic interactions among these low-abundance species, forming a connected network, and a few isolated competitive interactions.

  9. Species richness accelerates marine ecosystem restoration in the Coral Triangle.

    Science.gov (United States)

    Williams, Susan L; Ambo-Rappe, Rohani; Sur, Christine; Abbott, Jessica M; Limbong, Steven R

    2017-11-07

    Ecosystem restoration aims to restore biodiversity and valuable functions that have been degraded or lost. The Coral Triangle is a hotspot for marine biodiversity held in its coral reefs, seagrass meadows, and mangrove forests, all of which are in global decline. These coastal ecosystems support valuable fisheries and endangered species, protect shorelines, and are significant carbon stores, functions that have been degraded by coastal development, destructive fishing practices, and climate change. Ecosystem restoration is required to mitigate these damages and losses, but its practice is in its infancy in the region. Here we demonstrate that species diversity can set the trajectory of restoration. In a seagrass restoration experiment in the heart of the Coral Triangle (Sulawesi, Indonesia), plant survival and coverage increased with the number of species transplanted. Our results highlight the positive role biodiversity can play in ecosystem restoration and call for revision of the common restoration practice of establishing a single target species, particularly in regions having high biodiversity. Coastal ecosystems affect human well-being in many important ways, and restoration will become ever more important as conservation efforts cannot keep up with their loss. Published under the PNAS license.

  10. Species richness and occupancy estimation in communities subject to temporary emigration

    Science.gov (United States)

    Kery, M.; Royle, J. Andrew; Plattner, M.; Dorazio, R.M.

    2009-01-01

    Species richness is the most common biodiversity metric, although typically some species remain unobserved. Therefore, estimates of species richness and related quantities should account for imperfect detectability. Community dynamics can often be represented as superposition of species-specific phenologies (e. g., in taxa with well-defined flight [insects], activity [rodents], or vegetation periods [plants]). We develop a model for such predictably open communities wherein species richness is expressed as the sum over observed and unobserved species of estimated species-specific and site-specific occurrence indicators and where seasonal occurrence is modeled as a species-specific function of time. Our model is a multispecies extension of a multistate model with one unobservable state and represents a parsimonious way of dealing with a widespread form of 'temporary emigration.'' For illustration we use Swiss butterfly monitoring data collected under a robust design (RD); species were recorded on 13 transects during two secondary periods within data, where secondary samples are pooled. The latter model yielded unrealistically high estimates of total community size of 274 species. In contrast, estimates were similar under models applied to RD data with constant (122) or seasonally varying (126) detectability for each species, but the former was more parsimonious and therefore used for inference. Per transect, 6 44 (mean 21.1) species were detected. Species richness estimates averaged 29.3; therefore only 71% (range 32-92%) of all species present were ever detected. In any primary period, 0.4-5.6 species present were overlooked. Detectability varied by species and averaged 0.88 per primary sampling period. Our modeling framework is extremely flexible; extensions such as covariates for the occurrence or detectability of individual species are easy. It should be useful for communities with a predictable form of temporary emigration where rigorous estimation of community

  11. Species-rich grassland can persist under nitrogen-rich but phosphorus-limited conditions

    NARCIS (Netherlands)

    Dobben, van Han F.; Wamelink, Wieger; Slim, Pieter A.; Kamiński, Jan; Piórkowski, Hubert

    2017-01-01

    Aim: Deposition of nitrogen is assumed to cause loss of botanical diversity, probably through increased production and exclusion of less competitive species. However, if production is (co-)limited by phosphorus, acceleration of the phosphorus cycle may be responsible for the diversity loss and,

  12. Elevational pattern of bird species richness and its causes along a central Himalaya gradient, China.

    Science.gov (United States)

    Pan, Xinyuan; Ding, Zhifeng; Hu, Yiming; Liang, Jianchao; Wu, Yongjie; Si, Xingfeng; Guo, Mingfang; Hu, Huijian; Jin, Kun

    2016-01-01

    This study examines the relative importance of six variables: area, the mid-domain effect, temperature, precipitation, productivity, and habitat heterogeneity on elevational patterns of species richness for breeding birds along a central Himalaya gradient in the Gyirong Valley, the longest of five canyons in the Mount Qomolangma National Nature Reserve. We conducted field surveys in each of twelve elevational bands of 300 m between 1,800 and 5,400 m asl four times throughout the entire wet season. A total of 169 breeding bird species were recorded and most of the species (74%) were small-ranged. The species richness patterns of overall, large-ranged and small-ranged birds were all hump-shaped, but with peaks at different elevations. Large-ranged species and small-ranged species contributed equally to the overall richness pattern. Based on the bivariate and multiple regression analyses, area and precipitation were not crucial factors in determining the species richness along this gradient. The mid-domain effect played an important role in shaping the richness pattern of large-ranged species. Temperature was negatively correlated with overall and large-ranged species but positively correlated with small-ranged species. Productivity was a strong explanatory factor among all the bird groups, and habitat heterogeneity played an important role in shaping the elevational richness patterns of overall and small-ranged species. Our results highlight the need to conserve primary forest and intact habitat in this area. Furthermore, we need to increase conservation efforts in this montane biodiversity hotspot in light of increasing anthropogenic activities and land use pressure.

  13. Richness of lichen species, especially of threatened ones, is promoted by management methods furthering stand continuity.

    Directory of Open Access Journals (Sweden)

    Steffen Boch

    Full Text Available Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin, the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m(2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging, various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks. We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1 conserving unmanaged forests, (2 promoting silvicultural methods assuring stand continuity, (3 conserving old trees in managed forests, (4 promoting stands of native deciduous

  14. Richness of Lichen Species, Especially of Threatened Ones, Is Promoted by Management Methods Furthering Stand Continuity

    Science.gov (United States)

    Boch, Steffen; Prati, Daniel; Hessenmöller, Dominik; Schulze, Ernst-Detlef; Fischer, Markus

    2013-01-01

    Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin), the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging), various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks). We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1) conserving unmanaged forests, (2) promoting silvicultural methods assuring stand continuity, (3) conserving old trees in managed forests, (4) promoting stands of native deciduous tree species

  15. High tropical net diversification drives the New World latitudinal gradient in palm (Arecaceae) species richness

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Borchsenius, Finn; Bjorholm, Stine Wendelboe

    2008-01-01

    /temperature and water availability. These patterns therefore reflect net diversification at both deep and shallow levels in the phylogeny. Richness also increased with range in elevation, but this was only reflected in the MS/G pattern and therefore reflects recent diversification. Main conclusions The geographical......Aim Species richness exhibits striking geographical variation, but the processes that drive this variation are unresolved. We investigated the relative importance of two hypothesized evolutionary causes for the variation in palm species richness across the New World: time for diversification...

  16. Species richness of vertebrates in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Krojerová-Prokešová, Jarmila; Barančeková, Miroslava; Šímová, P.; Šálek, M.; Anděra, M.; Bejček, V.; Hanák, V.; Hanel, L.; Lusk, Stanislav; Mikátová, B.; Moravec, J.; Šťastný, K.; Zima, Jan

    2008-01-01

    Roč. 57, č. 4 (2008), s. 452-464 ISSN 0139-7893 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60930519 Keywords : mapping squares * species numbers * environmental variables * PCA Subject RIV: EH - Ecology, Behaviour Impact factor: 0.522, year: 2008 http://www.ivb.cz/folia/57/4/452-464_MS1417.pdf

  17. The richness and diversity of Lepidoptera species in different ...

    African Journals Online (AJOL)

    The family Nymphalidae was the most dominant one in the parc with 32.48%. The diversity index (H' and H'max) and the equitability (E) calculated for the 6 types of habitats is H'= 2,74 bits, H'max = 4,09 bits and E = 0,67 bits, meaning that the Lepidoptera species are at equilibrium with the different types of habitat which ...

  18. Description of three new species of Labena Cresson from Mexico (Hymenoptera, Ichneumonidae, Labeninae), with notes on tropical species richness.

    Science.gov (United States)

    González-Moreno, Alejandra; Bordera, Santiago; Sääksjärvi, Ilari Eerikki

    2015-04-22

    Three new species of Labena Cresson (Ichneumonidae, Labeninae); L. littoralis sp. nov., L. tekalina sp. nov. and L. madoricola sp. nov. are described and illustrated. Material was collected with Malaise traps in 2008 and 2009 in the Biosphere Reserve Ria Lagartos (Mexico). Diagnostic characters to distinguish them from all other New World species of the genus are provided. In addition, the tropical species richness of the genus is shortly discussed.

  19. External Morphology of Adult Citrus Butterfly, Papilio memnon (Linnaeus, 1758) and Seasonal Abundance of the Species

    International Nuclear Information System (INIS)

    Ni Ni Win

    2005-10-01

    Sexual dimorphism is obvious in Papilio memnon. The female adult resembles that of Papilio polytes another citrus butterfly species. However, marked difference is observed in the size and red spots on the base of the forewing. The adult male P. memnon is blue black in colour and red spots are present on the base of the underside of both for and hind wings. The win span of sexes ranges from 120mm to 150mm. The breeding season is from end of June to early part of January, the peak being in the month of November. The recorded diagnostic external features of this studied species are described supported by scaled photographs. Seasonal abundance of this species is also mentioned. It is learnt through the internet that a mounted specimen of this species fetched $2.95 in Malaysia. It is therefore concluded that successful rearing of this species in captivity could be of benefit to the country.

  20. Reversal in the relationship between species richness and turnover in a phytoplankton community.

    Science.gov (United States)

    Matthews, Blake; Pomati, Francesco

    2012-11-01

    Negative relationships between species richness and the rate of compositional turnover are common, suggesting that diverse communities have greater stability than depauperate ones; however, the mechanistic basis for this pattern is still widely debated. Species richness and turnover can covary either because they are mechanistically linked or because they share common environmental drivers. Few empirical studies have combined long-term changes in community composition with multiple drivers of environmental change, and so little is known about how the underlying mechanisms of species coexistence interact with changes in the mean and variability of environmental conditions. Here, we use a 33 year long time series (1976-2008) of phytoplankton community composition from Lake Zurich, to examine how environmental variation influences the relationship between richness and annual turnover. We find that the relationship between richness and annual turnover reverses midway through the time series (1992-1993), leading to a hump-shaped relationship between species richness and annual turnover. Using structural equation modeling we show that annual turnover and diversity are independently associated with different drivers of environmental change. Furthermore, we find that the observed annual sequences of community assembly give rise to rates of species accumulation that are more heterogeneous through time than expected by chance, likely owing to a high proportion of species showing significant autocorrelation and to strong positive covariation in the occurrences of species.

  1. Global assessment of the effects of terrestrial acidification on plant species richness

    International Nuclear Information System (INIS)

    Azevedo, Ligia B.; Zelm, Rosalie van; Hendriks, A. Jan; Bobbink, Roland; Huijbregts, Mark A.J.

    2013-01-01

    This study estimates the potential losses of vascular plant species richness due to terrestrial acidification for different world's biomes. We used empirical occurrence data of 2409 species from 140 studies and estimated the relative species richness – pH response curves using logistic regressions. The regressions were then used to quantify the fraction of species that are potentially lost due to soil pH changes. Although we found considerable variability within biomes, out results show that the pH at which species richness was maximized was found to be the lowest in (sub)tropical forests (pH = 4.1) and the highest in deserts (pH = 7.4). We also found that (sub)tropical moist forests are highly sensitive to decreases of in soil pH below 4.1. This study can be coupled with existing atmospheric deposition models to quantify the risk of species richness loss following soil acidification. Highlights: ► We compare the sensitivity of four biomes to soil acidification. ► We develop logistic regressions using observational field data. ► Sub(tropical) moist forests are highly affected by pH decreases. ► Logistic regressions can be linked to global scale atmospheric and soil fate models. -- Relationships of potential species richness loss along a soil pH gradient are proposed

  2. Improved fatty acid analysis of conjugated linoleic acid rich egg yolk triacylglycerols and phospholipid species.

    Science.gov (United States)

    Shinn, Sara; Liyanage, Rohana; Lay, Jack; Proctor, Andrew

    2014-07-16

    Reports from chicken conjugated linoleic acid (CLA) feeding trials are limited to yolk total fatty acid composition, which consistently described increased saturated fatty acids and decreased monounsaturated fatty acids. However, information on CLA triacylglycerol (TAG) and phospholipid (PL) species is limited. This study determined the fatty acid composition of total lipids in CLA-rich egg yolk produced with CLA-rich soy oil, relative to control yolks using gas chromatography with flame ionization detection (GC-FID), determined TAG and PL fatty acid compositions by thin-layer chromatography-GC-FID (TLC-GC-FID), identified intact PL and TAG species by TLC-matrix-assisted laser desorption/ionization mass spectrometry (TLC-MALDI-MS), and determined the composition of TAG and PL species in CLA and control yolks by direct flow infusion electrospray ionization MS (DFI ESI-MS). In total, 2 lyso-phosphatidyl choline (LPC) species, 1 sphingomyelin species, 17 phosphatidyl choline species, 19 TAG species, and 9 phosphatidyl ethanolamine species were identified. Fifty percent of CLA was found in TAG, occurring predominantly in C52:5 and C52:4 TAG species. CLA-rich yolks contained significantly more LPC than did control eggs. Comprehensive lipid profiling may provide insight on relationships between lipid composition and the functional properties of CLA-rich eggs.

  3. [Distribution and changes in species composition and abundance of ichthyoplankton in the Yangtze estuary].

    Science.gov (United States)

    Zhang, Heng; Yang, Sheng-Long; Meng, Hai-Xing

    2012-06-01

    Based on four surveys of eggs and larvae in the Yangtze estuary in 2005 (April and November) and 2006 (April and September), combined with the historical data of the wetland in 1990 (September) and 1991 (March), we analyzed seasonal changes in fish species composition and quantity of ichthyoplankton. Thirty-six species of egg and larvae were collected and marine fish species were the highest represented ecological guild. Average fish species and average abundance in spring were lower than in autumn for every survey. The total number of eggs in brackish water was higher than in fresh water, but the total number of larvae and juveniles in brackish water was lower. The abundance of eggs and larvae during from 2005 to 2006 in both spring and autumn was higher compared to those from 1990 to 1991. Obvious differences in species composition in September between 1990 and 2006 were found, especially for Erythroculter ilishaeformis and Neosalanx taihuensis. Fish species composition and quantity within the ichthyoplankton community has obviously changed in the Yangtze estuary over the last 20 years.

  4. Changes in Species Richness and Composition of Tiger Moths (Lepidoptera: Erebidae: Arctiinae) among Three Neotropical Ecoregions

    Science.gov (United States)

    Beccacece, Hernán Mario; Zeballos, Sebastián Rodolfo; Zapata, Adriana Inés

    2016-01-01

    Paraná, Yungas and Chaco Serrano ecoregions are among the most species-rich terrestrial habitats at higher latitude. However, the information for tiger moths, one of the most speciose groups of moths, is unknown in these ecoregions. In this study, we assess their species richness and composition in all three of these ecoregions. Also we investigated whether the species composition of tiger moths is influenced by climatic factors and altitude. Tiger moth species were obtained with samples from 71 sites using standardized protocols (21 sites were in Yungas, 19 in Paraná and 31 in Chaco Serrano). Rarefaction-extrapolation curves, non-parametric estimators for incidence and sample coverage indices were performed to assess species richness in the ecoregions studied. Non metric multidimensional scaling and adonis tests were performed to compare the species composition of tiger moths among ecoregions. Permutest analysis and Pearson correlation were used to evaluate the relationship among species composition and annual mean temperature, annual temperature range, annual precipitation, precipitation seasonality and altitude. Among ecoregions Paraná was the richest with 125 species, followed by Yungas with 63 species and Chaco Serrano with 24 species. Species composition differed among these ecoregions, although Yungas and Chaco Serrano were more similar than Paraná. Species composition was significantly influenced by climatic factors and altitude. This study showed that species richness and species composition of tiger moths differed among the three ecoregions assessed. Furthermore, not only climatic factors and altitude influence the species composition of tiger moths among ecoregions, but also climatic seasonality at higher latitude in Neotropical South America becomes an important factor. PMID:27681478

  5. Changes in Species Richness and Composition of Tiger Moths (Lepidoptera: Erebidae: Arctiinae among Three Neotropical Ecoregions.

    Directory of Open Access Journals (Sweden)

    Hernán Mario Beccacece

    Full Text Available Paraná, Yungas and Chaco Serrano ecoregions are among the most species-rich terrestrial habitats at higher latitude. However, the information for tiger moths, one of the most speciose groups of moths, is unknown in these ecoregions. In this study, we assess their species richness and composition in all three of these ecoregions. Also we investigated whether the species composition of tiger moths is influenced by climatic factors and altitude. Tiger moth species were obtained with samples from 71 sites using standardized protocols (21 sites were in Yungas, 19 in Paraná and 31 in Chaco Serrano. Rarefaction-extrapolation curves, non-parametric estimators for incidence and sample coverage indices were performed to assess species richness in the ecoregions studied. Non metric multidimensional scaling and adonis tests were performed to compare the species composition of tiger moths among ecoregions. Permutest analysis and Pearson correlation were used to evaluate the relationship among species composition and annual mean temperature, annual temperature range, annual precipitation, precipitation seasonality and altitude. Among ecoregions Paraná was the richest with 125 species, followed by Yungas with 63 species and Chaco Serrano with 24 species. Species composition differed among these ecoregions, although Yungas and Chaco Serrano were more similar than Paraná. Species composition was significantly influenced by climatic factors and altitude. This study showed that species richness and species composition of tiger moths differed among the three ecoregions assessed. Furthermore, not only climatic factors and altitude influence the species composition of tiger moths among ecoregions, but also climatic seasonality at higher latitude in Neotropical South America becomes an important factor.

  6. Global hotspots and correlates of alien species richness across taxonomic groups

    Science.gov (United States)

    Dawson, Wayne; Moser, Dietmar; van Kleunen, Mark; Kreft, Holger; Pergl, Jan; Pysek, Petr; Weigelt, Patrick; Winter, Marten; Lenzner, Bernd; Blackburn, Tim M.; Dyer, Ellie; Cassey, Phillip; Scrivens, Sally-Louise; Economo, Evan P.; Guenard, Benoit; Capinha, Cesar; Seebens, Hanno; Garcia-Diaz, Pablo; Nentwig, Wolfgang; Garcia-Berthou, Emili; Casal, Christine; Mandrak, Nicholas E.; Fuller, Pam; Meyer, Carsten; Essl, Franz

    2017-01-01

    Human-mediated transport beyond biogeographic barriers has led to the introduction and establishment of alien species in new regions worldwide. However, we lack a global picture of established alien species richness for multiple taxonomic groups. Here, we assess global patterns and potential drivers of established alien species richness across eight taxonomic groups (amphibians, ants, birds, freshwater fishes, mammals, vascular plants, reptiles and spiders) for 186 islands and 423 mainland regions. Hotspots of established alien species richness are predominantly island and coastal mainland regions. Regions with greater gross domestic product per capita, human population density, and area have higher established alien richness, with strongest effects emerging for islands. Ants and reptiles, birds and mammals, and vascular plants and spiders form pairs of taxonomic groups with the highest spatial congruence in established alien richness, but drivers explaining richness differ between the taxa in each pair. Across all taxonomic groups, our results highlight the need to prioritize prevention of further alien species introductions to island and coastal mainland regions globally.

  7. Species richness and distribution of chondrichthyan fishes in the Arctic Ocean and adjacent seas

    DEFF Research Database (Denmark)

    Lynghammar, A.; Christiansen, J. S.; Mecklenburg, C. W.

    2013-01-01

    The sea ice cover decreases and human activity increases in Arctic waters. Fisheries and bycatch issues, shipping and petroleum exploitation (pollution issues) make it imperative to establish biological baselines for the marine fishes inhabiting the Arctic Ocean and adjacent seas (AOAS). Species...... richness, zoogeographic affiliations and Red List statuses among chondrichthyan fishes (Chondrichthyes) were examined across 16 AOAS regions as a first step towards credible conservation actions. Published literature and museum vouchers were consulted for presence/absence data. Although many regions...... are poorly sampled, 49 chondrichthyan species have been reported from the AOAS. Skates and rays are the most species-rich taxon, represented by 27 species in family Rajidae and one species in family Dasyatidae. The sharks comprise 20 species in 13 families and the chimaeras one species in family Chimaeridae...

  8. Disentangling the Role of Climate, Topography and Vegetation in Species Richness Gradients.

    Directory of Open Access Journals (Sweden)

    Mario R Moura

    Full Text Available Environmental gradients (EG related to climate, topography and vegetation are among the most important drivers of broad scale patterns of species richness. However, these different EG do not necessarily drive species richness in similar ways, potentially presenting synergistic associations when driving species richness. Understanding the synergism among EG allows us to address key questions arising from the effects of global climate and land use changes on biodiversity. Herein, we use variation partitioning (also know as commonality analysis to disentangle unique and shared contributions of different EG in explaining species richness of Neotropical vertebrates. We use three broad sets of predictors to represent the environmental variability in (i climate (annual mean temperature, temperature annual range, annual precipitation and precipitation range, (ii topography (mean elevation, range and coefficient of variation of elevation, and (iii vegetation (land cover diversity, standard deviation and range of forest canopy height. The shared contribution between two types of EG is used to quantify synergistic processes operating among EG, offering new perspectives on the causal relationships driving species richness. To account for spatially structured processes, we use Spatial EigenVector Mapping models. We perform analyses across groups with distinct dispersal abilities (amphibians, non-volant mammals, bats and birds and discuss the influence of vagility on the partitioning results. Our findings indicate that broad scale patterns of vertebrate richness are mainly affected by the synergism between climate and vegetation, followed by the unique contribution of climate. Climatic factors were relatively more important in explaining species richness of good dispersers. Most of the variation in vegetation that explains vertebrate richness is climatically structured, supporting the productivity hypothesis. Further, the weak synergism between topography and

  9. Species composition, distribution and abundance of chaetodontidae along reef transects in the Flores Sea

    Science.gov (United States)

    Adrim, Mohammad; Hutomo, Malikusworo

    Observations on chaetodontid fishes were made by applying a visual census technique at 13 coral reef locations in the Flores Sea region in October and November 1984. These observations were made along 50 m transect lines, parallel to the shore or the reef edge at depths between 3 to 12 m. Twenty-three species of Chaetodontidae were observed, representing three genera: Chaetodon (20 species), Heniochus (2 species) and Forcipiger (1 species). Chaetodon kleini, C. trifasciatus, C. melannotus and C. baronessa proved to be the most abundant species, and among them C. kleini and C. trifasciatus were the most widely distributed ones. Chaetodon semeion and C. mertensi were the rarest species. The greatest number of individuals (77) was counted at station 4.268 near Tanjung Burung, Sumbawa, while the greatest number of species (14) was observed at station 4.257, north of Komodo. The lowest number of individuals (17) was counted at station 4.175 near P. Bahuluang, Salayer, while station 4.251 near Teluk Slawi, Komodo, was inhabited by the smallest numbver of species (2). Numerical classification by using the Bray Curtis dissimilarity index resulted in three groups of entities. The first group was characterized by predomination of C. kleini and the second by predomination of C. melannotus. The third one was a loose group not characterized by any predominant species. The analyses indicated that the similarities of the chaetodontid communities between locations are not related to the distance between them, but rather to habitat conditions. For example predomination of C. melannotus is strongly related to the predomination of soft coral. Compared to other areas of Indonesia, e.g. Bali, Seribu Islands, Batam, Sunda Strait, and Ambon Bay, the Flores Sea reefs have a more abundant and more diverse chaetodontid fauna.

  10. Avian species richness in relation to intensive forest management practices in early seral tree plantations.

    Science.gov (United States)

    Jones, Jay E; Kroll, Andrew J; Giovanini, Jack; Duke, Steven D; Ellis, Tana M; Betts, Matthew G

    2012-01-01

    Managers of landscapes dedicated to forest commodity production require information about how practices influence biological diversity. Individual species and communities may be threatened if management practices truncate or simplify forest age classes that are essential for reproduction and survival. For instance, the degradation and loss of complex diverse forest in young age classes have been associated with declines in forest-associated Neotropical migrant bird populations in the Pacific Northwest, USA. These declines may be exacerbated by intensive forest management practices that reduce hardwood and broadleaf shrub cover in order to promote growth of economically valuable tree species in plantations. We used a Bayesian hierarchical model to evaluate relationships between avian species richness and vegetation variables that reflect stand management intensity (primarily via herbicide application) on 212 tree plantations in the Coast Range, Oregon, USA. Specifically, we estimated the influence of broadleaf hardwood vegetation cover, which is reduced through herbicide applications, on bird species richness and individual species occupancy. Our model accounted for imperfect detection. We used average predictive comparisons to quantify the degree of association between vegetation variables and species richness. Both conifer and hardwood cover were positively associated with total species richness, suggesting that these components of forest stand composition may be important predictors of alpha diversity. Estimates of species richness were 35-80% lower when imperfect detection was ignored (depending on covariate values), a result that has critical implications for previous efforts that have examined relationships between forest composition and species richness. Our results revealed that individual and community responses were positively associated with both conifer and hardwood cover. In our system, patterns of bird community assembly appear to be associated with

  11. Patterns and multi-scale drivers of phytoplankton species richness in temperate peri-urban lakes

    Energy Technology Data Exchange (ETDEWEB)

    Catherine, Arnaud, E-mail: arnocat@mnhn.fr [UMR7245 MCAM MNHN-CNRS, Muséum National d' Histoire Naturelle, CC 39, 12 rue Buffon, F-75231 Paris, Cedex 05 (France); Selma, Maloufi, E-mail: maloufi@mnhn.fr [UMR7245 MCAM MNHN-CNRS, Muséum National d' Histoire Naturelle, CC 39, 12 rue Buffon, F-75231 Paris, Cedex 05 (France); Mouillot, David, E-mail: david.mouillot@univ-montp2.fr [UMR 9190 MARBEC UM2-CNRS-IRD-UM1-IFREMER, CC 93, Place Eugène Bataillon, Université de Montpellier 2, F-34095 Montpellier (France); Troussellier, Marc, E-mail: troussel@univ-montp2.fr [UMR 9190 MARBEC UM2-CNRS-IRD-UM1-IFREMER, CC 93, Place Eugène Bataillon, Université de Montpellier 2, F-34095 Montpellier (France); Bernard, Cécile, E-mail: cbernard@mnhn.fr [UMR7245 MCAM MNHN-CNRS, Muséum National d' Histoire Naturelle, CC 39, 12 rue Buffon, F-75231 Paris, Cedex 05 (France)

    2016-07-15

    Local species richness (SR) is a key characteristic affecting ecosystem functioning. Yet, the mechanisms regulating phytoplankton diversity in freshwater ecosystems are not fully understood, especially in peri-urban environments where anthropogenic pressures strongly impact the quality of aquatic ecosystems. To address this issue, we sampled the phytoplankton communities of 50 lakes in the Paris area (France) characterized by a large gradient of physico-chemical and catchment-scale characteristics. We used large phytoplankton datasets to describe phytoplankton diversity patterns and applied a machine-learning algorithm to test the degree to which species richness patterns are potentially controlled by environmental factors. Selected environmental factors were studied at two scales: the lake-scale (e.g. nutrients concentrations, water temperature, lake depth) and the catchment-scale (e.g. catchment, landscape and climate variables). Then, we used a variance partitioning approach to evaluate the interaction between lake-scale and catchment-scale variables in explaining local species richness. Finally, we analysed the residuals of predictive models to identify potential vectors of improvement of phytoplankton species richness predictive models. Lake-scale and catchment-scale drivers provided similar predictive accuracy of local species richness (R{sup 2} = 0.458 and 0.424, respectively). Both models suggested that seasonal temperature variations and nutrient supply strongly modulate local species richness. Integrating lake- and catchment-scale predictors in a single predictive model did not provide increased predictive accuracy; therefore suggesting that the catchment-scale model probably explains observed species richness variations through the impact of catchment-scale variables on in-lake water quality characteristics. Models based on catchment characteristics, which include simple and easy to obtain variables, provide a meaningful way of predicting phytoplankton

  12. Patterns and multi-scale drivers of phytoplankton species richness in temperate peri-urban lakes

    International Nuclear Information System (INIS)

    Catherine, Arnaud; Selma, Maloufi; Mouillot, David; Troussellier, Marc; Bernard, Cécile

    2016-01-01

    Local species richness (SR) is a key characteristic affecting ecosystem functioning. Yet, the mechanisms regulating phytoplankton diversity in freshwater ecosystems are not fully understood, especially in peri-urban environments where anthropogenic pressures strongly impact the quality of aquatic ecosystems. To address this issue, we sampled the phytoplankton communities of 50 lakes in the Paris area (France) characterized by a large gradient of physico-chemical and catchment-scale characteristics. We used large phytoplankton datasets to describe phytoplankton diversity patterns and applied a machine-learning algorithm to test the degree to which species richness patterns are potentially controlled by environmental factors. Selected environmental factors were studied at two scales: the lake-scale (e.g. nutrients concentrations, water temperature, lake depth) and the catchment-scale (e.g. catchment, landscape and climate variables). Then, we used a variance partitioning approach to evaluate the interaction between lake-scale and catchment-scale variables in explaining local species richness. Finally, we analysed the residuals of predictive models to identify potential vectors of improvement of phytoplankton species richness predictive models. Lake-scale and catchment-scale drivers provided similar predictive accuracy of local species richness (R"2 = 0.458 and 0.424, respectively). Both models suggested that seasonal temperature variations and nutrient supply strongly modulate local species richness. Integrating lake- and catchment-scale predictors in a single predictive model did not provide increased predictive accuracy; therefore suggesting that the catchment-scale model probably explains observed species richness variations through the impact of catchment-scale variables on in-lake water quality characteristics. Models based on catchment characteristics, which include simple and easy to obtain variables, provide a meaningful way of predicting phytoplankton

  13. Limited sampling hampers "big data" estimation of species richness in a tropical biodiversity hotspot.

    Science.gov (United States)

    Engemann, Kristine; Enquist, Brian J; Sandel, Brody; Boyle, Brad; Jørgensen, Peter M; Morueta-Holme, Naia; Peet, Robert K; Violle, Cyrille; Svenning, Jens-Christian

    2015-02-01

    Macro-scale species richness studies often use museum specimens as their main source of information. However, such datasets are often strongly biased due to variation in sampling effort in space and time. These biases may strongly affect diversity estimates and may, thereby, obstruct solid inference on the underlying diversity drivers, as well as mislead conservation prioritization. In recent years, this has resulted in an increased focus on developing methods to correct for sampling bias. In this study, we use sample-size-correcting methods to examine patterns of tropical plant diversity in Ecuador, one of the most species-rich and climatically heterogeneous biodiversity hotspots. Species richness estimates were calculated based on 205,735 georeferenced specimens of 15,788 species using the Margalef diversity index, the Chao estimator, the second-order Jackknife and Bootstrapping resampling methods, and Hill numbers and rarefaction. Species richness was heavily correlated with sampling effort, and only rarefaction was able to remove this effect, and we recommend this method for estimation of species richness with "big data" collections.

  14. A unified model of avian species richness on islands and continents.

    Science.gov (United States)

    Kalmar, Attila; Currie, David J

    2007-05-01

    How many species in a given taxon should be found in a delimited area in a specified place in the world? Some recent literature suggests that the answer to this question depends strongly on the geographical, evolutionary, and ecological context. For example, current theory suggests that species accumulate as a function of area differently on continents and islands. Species richness-climate relationships have been examined separately on continents and on islands. This study tests the hypotheses that (1) the functional relationship between richness and climate is the same on continents and islands; (2) the species-area slope depends on distance-based isolation; (3) species-area relationships differ among land bridge islands, oceanic islands, and continents; (4) richness differs among biogeographic regions independently of climate and isolation. We related bird species numbers in a worldwide sample of 240 continental parcels and 346 islands to several environmental variables. We found that breeding bird richness varies similarly on islands and on continents as a function of mean annual temperature, an area x precipitation interaction, and the distance separating insular samples from the nearest continent (R2 = 0.86). Most studies to date have postulated that the slope of the species-area relationship depends upon isolation. In contrast, we found no such interaction. A richness-environment relationship derived using Old World sites accurately predicts patterns of richness in the New World and vice versa (R2 = 0.85). Our results suggest that most of the global variation in richness is not strongly context-specific; rather, it reflects a small number of general environmental constraints operating on both continents and islands.

  15. Seed Density Significantly Affects Species Richness and Composition in Experimental Plant Communities

    Czech Academy of Sciences Publication Activity Database

    Münzbergová, Zuzana

    2012-01-01

    Roč. 7, č. 10 (2012), e46704 E-ISSN 1932-6203 R&D Projects: GA ČR GAP505/10/0593 Institutional support: RVO:67985939 Keywords : species richness * seed rain * species composition Subject RIV: EF - Botanics Impact factor: 3.730, year: 2012

  16. The role of spatial scale and the perception of large-scale species-richness patterns

    DEFF Research Database (Denmark)

    Rahbek, Carsten

    2005-01-01

    Despite two centuries of exploration, our understanding of factors determining the distribution of life on Earth is in many ways still in its infancy. Much of the disagreement about governing processes of variation in species richness may be the result of differences in our perception of species...

  17. Terrain and vegetation structural influences on local avian species richness in two mixed-conifer forests

    Science.gov (United States)

    Jody C. Vogeler; Andrew T. Hudak; Lee A. Vierling; Jeffrey Evans; Patricia Green; Kerri T. Vierling

    2014-01-01

    Using remotely-sensed metrics to identify regions containing high animal diversity and/or specific animal species or guilds can help prioritize forest management and conservation objectives across actively managed landscapes. We predicted avian species richness in two mixed conifer forests, Moscow Mountain and Slate Creek, containing different management contexts and...

  18. Effects of 'target' plant species body size on neighbourhood species richness and composition in old-field vegetation.

    Directory of Open Access Journals (Sweden)

    Brandon S Schamp

    Full Text Available Competition is generally regarded as an important force in organizing the structure of vegetation, and evidence from several experimental studies of species mixtures suggests that larger mature plant size elicits a competitive advantage. However, these findings are at odds with the fact that large and small plant species generally coexist, and relatively smaller species are more common in virtually all plant communities. Here, we use replicates of ten relatively large old-field plant species to explore the competitive impact of target individual size on their surrounding neighbourhoods compared to nearby neighbourhoods of the same size that are not centred by a large target individual. While target individuals of the largest of our test species, Centaurea jacea L., had a strong impact on neighbouring species, in general, target species size was a weak predictor of the number of other resident species growing within its immediate neighbourhood, as well as the number of resident species that were reproductive. Thus, the presence of a large competitor did not restrict the ability of neighbouring species to reproduce. Lastly, target species size did not have any impact on the species size structure of neighbouring species; i.e. they did not restrict smaller, supposedly poorer competitors, from growing and reproducing close by. Taken together, these results provide no support for a size-advantage in competition restricting local species richness or the ability of small species to coexist and successfully reproduce in the immediate neighbourhood of a large species.

  19. Geography, topography, and history affect realized-to-potential tree species richness patterns in Europe

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Fitzpatrick, Matthew C.; Normand, Signe

    2010-01-01

    by assembly from regional species pools. Using the European tree flora as our study system, we implemented a novel approach to assess the relative importance of local and regional mechanisms that control local species richness. We first identified species pools that tolerate particular local environments....../P richness ratio estimates, but we found consistent support for a negative effect of regional geographic fragmentation and a positive topographic effect. We also identified fairly broad support for the predicted effect of accessibility. We conclude that local tree assemblages in Europe often fail to realize...

  20. Global and Regional Patterns in Riverine Fish Species Richness: A Review

    Directory of Open Access Journals (Sweden)

    Thierry Oberdorff

    2011-01-01

    Full Text Available We integrate the respective role of global and regional factors driving riverine fish species richness patterns, to develop a synthetic model of potential mechanisms and processes generating these patterns. This framework allows species richness to be broken down into different components specific to each spatial extent and to establish links between these components and the processes involved. This framework should help to answer the questions that are currently being asked by society, including the effects of species invasions, habitat loss, or fragmentation and climate change on freshwater biodiversity.

  1. The fish fauna of Anambra river basin, Nigeria: species abundance and morphometry

    Directory of Open Access Journals (Sweden)

    Gregory Ejikeme Odo

    2009-06-01

    Full Text Available The fish yields of most Nigeria inland waters are generally on the decline for causes that may range from inadequate management of the fisheries to degradation of the water bodies. Sustainable exploitation requires knowledge of the ichthyofaunal composition in the water bodies. We did a survey of fish species in Anambra river basin for 22 months. Fish samples were collected using four different gears -hook and line of size 13, caste nets, gill nets, and cages of mesh sizes of 50mm, 75mm, and 100mm each. We recorded 52 fish species belonging to 17 families: 171, 236, and 169 individuals at Ogurugu, Otuocha, and Nsugbe stations respectively. Two families, Characidae, 19.5 %, and Mochokidae, 11.8%, constituted the dominant fish families in the river. The dominant fish species were Citherinus citherius, 9.02%, and Alestes nurse, 7.1%. Other fish species with significant abundance were Synodontis clarias 6.9%, Macrolepidotus curvier 5.7%, Labeo coubie 5.4%, Distichodus rostrtus 4.9%, and Schilbe mystus 4.5%. The meristic features of the two most abundant fish species caught are as follows: Citharinus citharius dorsal fins 20, anal fins 30, caudal fins 21, pectoral fins, 9 and 8 ventral fins, and Alestes nurse 10 dorsal fins, 14 anal fins, 31 caudal fins, 7 pectoral fins and 6 ventral fins. The morphometric features of the two most abundant fish species are Citharinus citharius total length 300mm, standard length 231mm, head length 69mm, body length 101mm, body girth 176 mm, body weight 900mg. Alestes nurse total length 200, standard length 140mm, head length 60mm, body length 80mm, body girth120mm, body weight 400mg. The most abundant animal utilizing the basin was Ardea cinerea(D3 with 22.2% occurrence (D4 and this was followed by Caprini with 13.51%, and Varanus niloticus, 10.04%. The least abundant animals utilizing basin were Chephalophus rufilatus, and Erythrocebus patas, with 0.58% each of occurrence. Rev. Biol. Trop. 57 (1-2: 177-186. Epub

  2. Relationships between water transparency and abundance of Cynodontidae species in the Bananal floodplain, Mato Grosso, Brazil

    Directory of Open Access Journals (Sweden)

    Cesar Enrique de Melo

    Full Text Available The Cerrado in the Central Brazil is currently one of the most threatened ecosystems in the world. As a result, the aquatic habitats in this biome also undergo great impacts. Alterations related to land-use change increase sediment loadings in rivers, streams and lakes, resulting in sedimentation and decrease in water transparency. Water transparency determines underwater visibility conditions, and as a consequence fish assemblages respond to spatial and temporal changes in this variable. This work aimed to examine the influence of transparency on the abundance and distribution of Cynodontidae species, a visually oriented predatory fish group. Fish sampling was conducted in 15 sites located between Mortes and Araguaia rivers in the Bananal floodplain, Mato Grosso State. Regression analysis between relative abundance of Cynodontidae (in number of individuals and biomass and water transparency showed a positive and highly significant correlation, indicating that this group shows species-specific habitat affinities for clearer waters. These results suggest that the increase in water turbidity in this region can affect the patterns of abundance and distribution of the Cynodontidae species, as well as other visually oriented fishes.

  3. Microbial abundance in rhizosphere of medicinal and aromatic plant species in conventional and organic growing systems

    Directory of Open Access Journals (Sweden)

    Adamović Dušan

    2015-01-01

    Full Text Available This study was aimed at comparing the abundance of microorganisms in the rhizosphere of four different medicinal and aromatic plant species (basil, mint, dill and marigold grown under both conventional and organic management on the chernozem soil at the experimental field of Bački Petrovac (Institute of Field and Vegetable Crops, Novi Sad, Serbia. Two sampling terms (June 1 and July 18, 2012 were performed to collect samples for microbiological analyses. The microbial abundance was higher in organic than in conventional system while at the same time significant differences were obtained only with dill rhizosphere. The differences in number of microorganisms belonging to different groups relied upon both plant species and sampling term. Thus, in mint, the recorded number of azotobacters and fungi was significantly higher whereas the number of ammonifiers was significantly lower. The present results indicate that organic growing system affected the abundance of microorganisms in rhizosphere of species investigated, especially in the second term of sampling.

  4. Enhancement of local species richness in tundra by seed dispersal through guts of muskox and barnacle goose

    DEFF Research Database (Denmark)

    Bruun, Hans Henrik; Lundgren, Rebekka; Philipp, Marianne

    2008-01-01

    The potential contribution of vertebrate-mediated seed rain to the maintenance of plant community richness in a High Arctic ecosystem was investigated. We analyzed viable seed content in dung of the four numerically most important terrestrial vertebrates in Northeast Greenland - muskox (Ovibos...... moschatus), barnacle goose (Branta leucopsis), Arctic fox (Alopex lagopus) and Arctic hare (Lepus arcticus). High numbers of plant propagules were found in the dung of muskox and barnacle goose. Seeds of many plant species were found in the faeces of one vertebrate species only. Propagule composition...... in barnacle goose droppings was relatively uniform over samples, with a high abundance of the nutritious bulbils of Polygonum viviparum (Bistorta vivipara), suggesting that geese have a narrow habitat preference and feed selectively. Propagule composition in muskox dung was diverse and heterogeneous among...

  5. Sampling designs matching species biology produce accurate and affordable abundance indices.

    Science.gov (United States)

    Harris, Grant; Farley, Sean; Russell, Gareth J; Butler, Matthew J; Selinger, Jeff

    2013-01-01

    Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion), and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km(2) cells) and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture sessions

  6. Sampling designs matching species biology produce accurate and affordable abundance indices

    Directory of Open Access Journals (Sweden)

    Grant Harris

    2013-12-01

    Full Text Available Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling, it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS data from 42 Alaskan brown bears (Ursus arctos. Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion, and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km2 cells and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture

  7. Sampling designs matching species biology produce accurate and affordable abundance indices

    Science.gov (United States)

    Farley, Sean; Russell, Gareth J.; Butler, Matthew J.; Selinger, Jeff

    2013-01-01

    Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion), and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km2 cells) and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture sessions, which

  8. Spatial congruence in language and species richness but not threat in the world's top linguistic hotspot.

    Science.gov (United States)

    Turvey, Samuel T; Pettorelli, Nathalie

    2014-12-07

    Languages share key evolutionary properties with biological species, and global-level spatial congruence in richness and threat is documented between languages and several taxonomic groups. However, there is little understanding of the functional connection between diversification or extinction in languages and species, or the relationship between linguistic and species richness across different spatial scales. New Guinea is the world's most linguistically rich region and contains extremely high biological diversity. We demonstrate significant positive relationships between language and mammal richness in New Guinea across multiple spatial scales, revealing a likely functional relationship over scales at which infra-island diversification may occur. However, correlations are driven by spatial congruence between low levels of language and species richness. Regional biocultural richness may have showed closer congruence before New Guinea's linguistic landscape was altered by Holocene demographic events. In contrast to global studies, we demonstrate a significant negative correlation across New Guinea between areas with high levels of threatened languages and threatened mammals, indicating that landscape-scale threats differ between these groups. Spatial resource prioritization to conserve biodiversity may not benefit threatened languages, and conservation policy must adopt a multi-faceted approach to protect biocultural diversity as a whole.

  9. Does species richness affect fine root biomass and production in young forest plantations?

    Science.gov (United States)

    Domisch, Timo; Finér, Leena; Dawud, Seid Muhie; Vesterdal, Lars; Raulund-Rasmussen, Karsten

    2015-02-01

    Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this could be that these stands were still young, and canopy closure had not always taken place, i.e. a situation where above- or below-ground competition did not yet exist. Another reason could be that the rooting traits of the tree species did not differ sufficiently to support niche differentiation. Our results suggested that functional group identity (i.e. conifers vs. broadleaved species) can be more important for below-ground biomass and production than the species richness itself, as conifers seemed to be more competitive in colonising the soil volume, compared to broadleaved species.

  10. Patterns of reptile and amphibian species richness along elevational gradients in Mt. Kenya

    Science.gov (United States)

    MALONZA, Patrick Kinyatta

    2015-01-01

    Faunal species richness is traditionally assumed to decrease with increasing elevation and decreasing primary productivity. Species richness is reported to peak at mid-elevation. This survey examines the herpetofaunal diversity and distribution in Mt. Kenya (central Kenya) by testing the hypothesis that changes in species richness with elevation relate to elevation-dependent changes in climate. Sampling along transects from an elevation of approximately 1 700 m in Chogoria forest block (wind-ward side) and approximately 2 600 m in Sirimon block (rain shadow zone) upwards in March 2009. This starts from the forest to montane alpine zones. Sampling of reptiles and amphibians uses pitfall traps associated with drift fences, time-limited searches and visual encounter surveys. The results show that herpetofaunal richness differs among three vegetation zones along the elevation gradient. Chogoria has higher biodiversity than Sirimon. More species occur at low and middle elevations and few exist at high elevations. The trends are consistent with expected optimum water and energy variables. The lower alpine montane zone has high species richness but low diversity due to dominance of some high elevations species. Unambiguous data do not support a mid-domain effect (mid-elevation peak) because the observed trend better fits a model in which climatic variables (rainfall and temperature) control species richness, which indirectly measures productivity. It is important to continue protection of all indigenous forests, especially at low to mid elevations. These areas are vulnerable to human destruction yet are home to some endemic species. Firebreaks can limit the spread of the perennial wildfires, especially on the moorlands. PMID:26646571

  11. Does species richness affect fine root biomass and production in young forest plantations?

    DEFF Research Database (Denmark)

    Domisch, Timo; Finér, Leena; Dawud, Seid Muhie

    2015-01-01

    Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass...... and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and determined...... be that these stands were still young, and canopy closure had not always taken place, i.e. a situation where above- or below-ground competition did not yet exist. Another reason could be that the rooting traits of the tree species did not differ sufficiently to support niche differentiation. Our results suggested...

  12. Testing the Effectiveness of Environmental Variables to Explain European Terrestrial Vertebrate Species Richness across Biogeographical Scales.

    Directory of Open Access Journals (Sweden)

    Maud Mouchet

    Full Text Available We compared the effectiveness of environmental variables, and in particular of land-use indicators, to explain species richness patterns across taxonomic groups and biogeographical scales (i.e. overall pan-Europe and ecoregions within pan-Europe. Using boosted regression trees that handle non-linear relationships, we compared the relative influence (as a measure of effectiveness of environmental variables related to climate, landscape (or habitat heterogeneity, land-use intensity or energy availability to explain European vertebrate species richness (birds, amphibians, and mammals at the continental and ecoregion scales. We found that dominant land cover and actual evapotranspiration that relate to energy availability were the main correlates of vertebrate species richness over Europe. At the ecoregion scale, we identified four distinct groups of ecoregions where species richness was essentially associated to (i seasonality of temperature, (ii actual evapotranspiration and/or mean annual temperature, (iii seasonality of precipitation, actual evapotranspiration and land cover and (iv and an even combination of the environmental variables. This typology of ecoregions remained valid for total vertebrate richness and the three vertebrate groups taken separately. Despite the overwhelming influence of land cover and actual evapotranspiration to explain vertebrate species richness patterns at European scale, the ranking of the main correlates of species richness varied between regions. Interestingly, landscape and land-use indicators did not stand out at the continental scale but their influence greatly increased in southern ecoregions, revealing the long-lasting human footprint on land-use-land-cover changes. Our study provides one of the first multi-scale descriptions of the variability in the ranking of correlates across several taxa.

  13. Rarity, Species Richness, and the Threat of Extinction—Are Plants the Same as Animals?

    OpenAIRE

    Knapp, Sandra

    2011-01-01

    Assessment of conservation status is done both for areas or habitats and for species (or taxa). IUCN Red List categories have been the principal method of categorising species in terms of extinction risk, and have been shown to be robust and helpful in the groups for which they have been developed. A recent study highlights properties associated with extinction risk in flowering plants, focusing on the species-rich hot spot of the Cape region of South Africa, and concludes that merely followi...

  14. Species-rich ecosystems are vulnerable to cascading extinctions in an increasingly variable world

    OpenAIRE

    Kaneryd, Linda; Borrvall, Charlotte; Berg, Sofia; Curtsdotter, Alva; Eklöf, Anna; Hauzy, Céline; Jonsson, Tomas; Münger, Peter; Setzer, Malin; Säterberg, Torbjörn; Ebenman, Bo

    2012-01-01

    Global warming leads to increased intensity and frequency of weather extremes. Such increased environmental variability might in turn result in increased variation in the demographic rates of interacting species with potentially important consequences for the dynamics of food webs. Using a theoretical approach, we here explore the response of food webs to a highly variable environment. We investigate how species richness and correlation in the responses of species to environmental fluctuation...

  15. Richness of Ancient Forest Plant Species Indicates Suitable Habitats for Macrofungi

    Czech Academy of Sciences Publication Activity Database

    Hofmeister, J.; Hošek, J.; Brabec, Marek; Dvořák, D.; Beran, M.; Deckerová, H.; Burel, J.; Kříž, M.; Borovička, Jan; Běťák, J.; Vašutová, Martina

    2014-01-01

    Roč. 23, č. 8 (2014), s. 2015-2031 ISSN 0960-3115 Grant - others:GA MŽP(CZ) SP/2D1/146/08 Institutional support: RVO:67985807 ; RVO:67985831 ; RVO:67179843 Keywords : diversity * forest continuity * forest management * Herb-layer plant species * red-listed species * species richness * surrogacy Subject RIV: BB - Applied Statistics, Operational Research; EH - Ecology, Behaviour (GLU-S); EH - Ecology, Behaviour (UEK-B) Impact factor: 2.365, year: 2014

  16. Diatom species abundance and morphologically-based dissolution proxies in coastal Southern Ocean assemblages

    Science.gov (United States)

    Warnock, Jonathan P.; Scherer, Reed P.

    2015-07-01

    Taphonomic processes alter diatom assemblages in sediments, thus potentially negatively impacting paleoclimate records at various rates across space, time, and taxa. However, quantitative taphonomic data is rarely included in diatom-based paleoenvironmental reconstructions and no objective standard exists for comparing diatom dissolution in sediments recovered from marine depositional settings, including the Southern Ocean's opal belt. Furthermore, identifying changes to diatom dissolution through time can provide insight into the efficiency of both upper water column nutrient recycling and the biological pump. This is significant in that reactive metal proxies (e.g. Al, Ti) in the sediments only account for post-depositional dissolution, not the water column where the majority of dissolution occurs. In order to assess the range of variability of responses to dissolution in a typical Southern Ocean diatom community and provide a quantitative guideline for assessing taphonomic variability in diatoms recovered from core material, a sediment trap sample was subjected to controlled, serial dissolution. By evaluating dissolution-induced changes to diatom species' relative abundance, three preservational categories of diatoms have been identified: gracile, intermediate, and robust. The relative abundances of these categories can be used to establish a preservation grade for diatom assemblages. However, changes to the relative abundances of diatom species in sediment samples may reflect taphonomic or ecological factors. In order to address this complication, relative abundance changes have been tied to dissolution-induced morphological change to the areolae of Fragilariopsis curta, a significant sea-ice indicator in Southern Ocean sediments. This correlation allows differentiation between gracile species loss to dissolution versus ecological factors or sediment winnowing. These results mirror a similar morphological dissolution index from a parallel study utilizing

  17. Epidemic disease decimates amphibian abundance, species diversity, and evolutionary history in the highlands of central Panama.

    Science.gov (United States)

    Crawford, Andrew J; Lips, Karen R; Bermingham, Eldredge

    2010-08-03

    Amphibian populations around the world are experiencing unprecedented declines attributed to a chytrid fungal pathogen, Batrachochytrium dendrobatidis. Despite the severity of the crisis, quantitative analyses of the effects of the epidemic on amphibian abundance and diversity have been unavailable as a result of the lack of equivalent data collected before and following disease outbreak. We present a community-level assessment combining long-term field surveys and DNA barcode data describing changes in abundance and evolutionary diversity within the amphibian community of El Copé, Panama, following a disease epidemic and mass-mortality event. The epidemic reduced taxonomic, lineage, and phylogenetic diversity similarly. We discovered that 30 species were lost, including five undescribed species, representing 41% of total amphibian lineage diversity in El Copé. These extirpations represented 33% of the evolutionary history of amphibians within the community, and variation in the degree of population loss and decline among species was random with respect to the community phylogeny. Our approach provides a fast, economical, and informative analysis of loss in a community whether measured by species or phylogenetic diversity.

  18. Parametric scaling from species relative abundances to absolute abundances in the computation of biological diversity: a first proposal using Shannon's entropy.

    Science.gov (United States)

    Ricotta, Carlo

    2003-01-01

    Traditional diversity measures such as the Shannon entropy are generally computed from the species' relative abundance vector of a given community to the exclusion of species' absolute abundances. In this paper, I first mention some examples where the total information content associated with a given community may be more adequate than Shannon's average information content for a better understanding of ecosystem functioning. Next, I propose a parametric measure of statistical information that contains both Shannon's entropy and total information content as special cases of this more general function.

  19. Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance.

    Directory of Open Access Journals (Sweden)

    Gail S Robertson

    Full Text Available Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis. With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes

  20. Freshwater fishes in Greek lakes: Species richness and body size patterns

    Directory of Open Access Journals (Sweden)

    Anthi Oikonomou

    2015-11-01

    Full Text Available Freshwater ecosystems are widely recognised as hotspots of biodiversity and endemism; thus they are of great value for conservation biogeography. Amongst the taxa found in freshwater ecosystems, fish are the ideal biological model for testing biogeographical patterns and have often been used in large-scale ecological and biogeographical analyses. Lakes of Greece provide a unique opportunity to test biogeographical theories, however, biogeographical studies in Greece at broader, regional, scales, based on the distribution of freshwater species, species richness and endemism, are scarce. The aim of the current study is to test the effect of key environmental factors and spatial variables on species richness of lacustrine fishes and to test their effect on species’ size distributions. We assembled datasets of species richness and body size and environmental (predictor factors for 13 Greek lakes. Model selection procedures revealed that fish species richness increased with ecosystem area and decreased with altitude. In addition, our results showed that latitude per se is a good predictor of body size. Indeed, the mean size of lacustrine communities in the northern and southern lake ecosystems differed significantly. These patterns reflect the biogeographical history of these areas and highlight the crucial role connectivity plays in communities’ species composition.

  1. Helminth species richness of introduced and native grey mullets (Teleostei: Mugilidae).

    Science.gov (United States)

    Sarabeev, Volodimir

    2015-08-01

    Quantitative complex analyses of parasite communities of invaders across different native and introduced populations are largely lacking. The present study provides a comparative analysis of species richness of helminth parasites in native and invasive populations of grey mullets. The local species richness differed between regions and host species, but did not differ when compared with invasive and native hosts. The size of parasite assemblages of endohelminths was higher in the Mediterranean and Azov-Black Seas, while monogeneans were the most diverse in the Sea of Japan. The helminth diversity was apparently higher in the introduced population of Liza haematocheilus than that in their native habitat, but this trend could not be confirmed when the size of geographic range and sampling efforts were controlled for. The parasite species richness at the infracommunity level of the invasive host population is significantly lower compared with that of the native host populations that lends support to the enemy release hypothesis. A distribution pattern of the infracommunity richness of acquired parasites by the invasive host can be characterized as aggregated and it is random in native host populations. Heterogeneity in the host susceptibility and vulnerability to acquired helminth species was assumed to be a reason of the aggregation of species numbers in the population of the invasive host. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Mammal predator and prey species richness are strongly linked at macroscales

    DEFF Research Database (Denmark)

    Sandom, Christopher James; Dalby, Lars; Fløjgaard, Camilla

    2013-01-01

    Predator–prey interactions play an important role for species composition and community dynamics at local scales, but their importance in shaping large-scale gradients of species richness remains unexplored. Here, we use global range maps, structural equation models (SEM), and comprehensive...... databases of dietary preferences and body masses of all terrestrial, non-volant mammals worldwide, to test whether (1) prey-bottom-up or predator- top-down relationships are important drivers of broad-scale species richness gradients once the environment and human influence has been accounted for, (2...... between them (e.g., large prey to small predators), suggesting that mass-related energetic and physiological constraints influence broad-scale richness links, especially for large-bodied mammals. Overall, our results support the idea that trophic interactions can be important drivers of large...

  3. Climate patterns as predictors of amphibians species richness and indicators of potential stress

    Science.gov (United States)

    Battaglin, W.; Hay, L.; McCabe, G.; Nanjappa, P.; Gallant, Alisa L.

    2005-01-01

    Amphibians occupy a range of habitats throughout the world, but species richness is greatest in regions with moist, warm climates. We modeled the statistical relations of anuran and urodele species richness with mean annual climate for the conterminous United States, and compared the strength of these relations at national and regional levels. Model variables were calculated for county and subcounty mapping units, and included 40-year (1960-1999) annual mean and mean annual climate statistics, mapping unit average elevation, mapping unit land area, and estimates of anuran and urodele species richness. Climate data were derived from more than 7,500 first-order and cooperative meteorological stations and were interpolated to the mapping units using multiple linear regression models. Anuran and urodele species richness were calculated from the United States Geological Survey's Amphibian Research and Monitoring Initiative (ARMI) National Atlas for Amphibian Distributions. The national multivariate linear regression (MLR) model of anuran species richness had an adjusted coefficient of determination (R2) value of 0.64 and the national MLR model for urodele species richness had an R2 value of 0.45. Stratifying the United States by coarse-resolution ecological regions provided models for anUrans that ranged in R2 values from 0.15 to 0.78. Regional models for urodeles had R2 values. ranging from 0.27 to 0.74. In general, regional models for anurans were more strongly influenced by temperature variables, whereas precipitation variables had a larger influence on urodele models.

  4. Use of fish parasite species richness indices in analyzing anthropogenically impacted coastal marine ecosystems

    Science.gov (United States)

    Dzikowski, R.; Paperna, I.; Diamant, A.

    2003-10-01

    The diversity of fish parasite life history strategies makes these species sensitive bioindicators of aquatic ecosystem health. While monoxenous (single-host) species may persist in highly perturbed, extreme environments, this is not necessarily true for heteroxenous (multiple-host) species. As many parasites possess complex life cycles and are transmitted through a chain of host species, their dependency on the latter to complete their life cycles renders them sensitive to perturbed environments. In the present study, parasite communities of grey mullet Liza aurata and Liza ramada (Mugilidae) were investigated at two Mediterranean coastal sites in northern Israel: the highly polluted Kishon Harbor (KH) and the relatively unspoiled reference site, Ma'agan Michael (MM). Both are estuarine sites in which grey mullet are one of the most common fish species. The results indicate that fish at the polluted site had significantly less trematode metacercariae than fish at the reference site. Heteroxenous gut helminths were completely absent at the polluted sampling site. Consequently, KH fish displayed lower mean parasite species richness. At the same time, KH fish mean monoxenous parasite richness was higher, although the prevalence of different monoxenous taxa was variable. Copepods had an increased prevalence while monogenean prevalence was significantly reduced at the polluted site. This variability may be attributed to the differential susceptibility of the parasites to the toxicity of different pollutants, their concentration, the exposure time and possible synergistic effects. In this study, we used the cumulative species curve model that extrapolates "true" species richness of a given habitat as a function of increasing sample size. We considered the heteroxenous and monoxenous species separately for each site, and comparison of curves yielded significant results. It is proposed to employ this approach, originally developed for estimating the "true" parasite

  5. Environmental and spatial controls of palm (Arecaceae) species richness across the Americas

    DEFF Research Database (Denmark)

    Bjorholm, Stine; Svenning, Jens-Christian; Skov, Flemming

    2005-01-01

    Our analysis suggests that in the Americas, palm species richness at spatial scales from 1° to 10° is most strongly controlled by water availability, although unknown broad-scale factors, perhaps soil, historical processes or geometric constraints, are also important.......Our analysis suggests that in the Americas, palm species richness at spatial scales from 1° to 10° is most strongly controlled by water availability, although unknown broad-scale factors, perhaps soil, historical processes or geometric constraints, are also important....

  6. New records and detailed distribution and abundance of selected arthropod species collected between 1999 and 2011 in Azorean native forests

    Science.gov (United States)

    Gaspar, Clara; Crespo, Luís Carlos Fonseca; Rigal, François; Cardoso, Pedro; Pereira, Fernando; Rego, Carla; Amorim, Isabel R.; Melo, Catarina; Aguiar, Carlos; André, Genage; Mendonça, Enésima P.; Ribeiro, Sérvio; Hortal, Joaquín; Santos, Ana M.C.; Barcelos, Luís; Enghoff, Henrik; Mahnert, Volker; Pita, Margarida T.; Ribes, Jordi; Baz, Arturo; Sousa, António B.; Vieira, Virgílio; Wunderlich, Jörg; Parmakelis, Aristeidis; Whittaker, Robert J.; Quartau, José Alberto; Serrano, Artur R.M.; Triantis, Kostas A.

    2016-01-01

    Abstract Background In this contribution we present detailed distribution and abundance data for arthropod species identified during the BALA – Biodiversity of Arthropods from the Laurisilva of the Azores (1999-2004) and BALA2 projects (2010-2011) from 18 native forest fragments in seven of the nine Azorean islands (all excluding Graciosa and Corvo islands, which have no native forest left). New information Of the total 286 species identified, 81% were captured between 1999 and 2000, a period during which only 39% of all the samples were collected. On average, arthropod richness for each island increased by 10% during the time frame of these projects. The classes Arachnida, Chilopoda and Diplopoda represent the most remarkable cases of new island records, with more than 30% of the records being novelties. This study stresses the need to expand the approaches applied in these projects to other habitats in the Azores, and more importantly to other less surveyed taxonomic groups (e.g. Diptera and Hymenoptera). These steps are fundamental for getting a more accurate assessment of biodiversity in the archipelago. PMID:28174509

  7. Species Distribution Modelling: Contrasting presence-only models with plot abundance data.

    Science.gov (United States)

    Gomes, Vitor H F; IJff, Stéphanie D; Raes, Niels; Amaral, Iêda Leão; Salomão, Rafael P; de Souza Coelho, Luiz; de Almeida Matos, Francisca Dionízia; Castilho, Carolina V; de Andrade Lima Filho, Diogenes; López, Dairon Cárdenas; Guevara, Juan Ernesto; Magnusson, William E; Phillips, Oliver L; Wittmann, Florian; de Jesus Veiga Carim, Marcelo; Martins, Maria Pires; Irume, Mariana Victória; Sabatier, Daniel; Molino, Jean-François; Bánki, Olaf S; da Silva Guimarães, José Renan; Pitman, Nigel C A; Piedade, Maria Teresa Fernandez; Mendoza, Abel Monteagudo; Luize, Bruno Garcia; Venticinque, Eduardo Martins; de Leão Novo, Evlyn Márcia Moraes; Vargas, Percy Núñez; Silva, Thiago Sanna Freire; Manzatto, Angelo Gilberto; Terborgh, John; Reis, Neidiane Farias Costa; Montero, Juan Carlos; Casula, Katia Regina; Marimon, Beatriz S; Marimon, Ben-Hur; Coronado, Euridice N Honorio; Feldpausch, Ted R; Duque, Alvaro; Zartman, Charles Eugene; Arboleda, Nicolás Castaño; Killeen, Timothy J; Mostacedo, Bonifacio; Vasquez, Rodolfo; Schöngart, Jochen; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Laurance, William F; Camargo, José Luís; Demarchi, Layon O; Laurance, Susan G W; de Sousa Farias, Emanuelle; Nascimento, Henrique Eduardo Mendonça; Revilla, Juan David Cardenas; Quaresma, Adriano; Costa, Flavia R C; Vieira, Ima Célia Guimarães; Cintra, Bruno Barçante Ladvocat; Castellanos, Hernán; Brienen, Roel; Stevenson, Pablo R; Feitosa, Yuri; Duivenvoorden, Joost F; Aymard C, Gerardo A; Mogollón, Hugo F; Targhetta, Natalia; Comiskey, James A; Vicentini, Alberto; Lopes, Aline; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Emilio, Thaise; Alonso, Alfonso; Neill, David; Dallmeier, Francisco; Ferreira, Leandro Valle; Araujo-Murakami, Alejandro; Praia, Daniel; do Amaral, Dário Dantas; Carvalho, Fernanda Antunes; de Souza, Fernanda Coelho; Feeley, Kenneth; Arroyo, Luzmila; Pansonato, Marcelo Petratti; Gribel, Rogerio; Villa, Boris; Licona, Juan Carlos; Fine, Paul V A; Cerón, Carlos; Baraloto, Chris; Jimenez, Eliana M; Stropp, Juliana; Engel, Julien; Silveira, Marcos; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Maas, Paul; Thomas-Caesar, Raquel; Henkel, Terry W; Daly, Doug; Paredes, Marcos Ríos; Baker, Tim R; Fuentes, Alfredo; Peres, Carlos A; Chave, Jerome; Pena, Jose Luis Marcelo; Dexter, Kyle G; Silman, Miles R; Jørgensen, Peter Møller; Pennington, Toby; Di Fiore, Anthony; Valverde, Fernando Cornejo; Phillips, Juan Fernando; Rivas-Torres, Gonzalo; von Hildebrand, Patricio; van Andel, Tinde R; Ruschel, Ademir R; Prieto, Adriana; Rudas, Agustín; Hoffman, Bruce; Vela, César I A; Barbosa, Edelcilio Marques; Zent, Egleé L; Gonzales, George Pepe Gallardo; Doza, Hilda Paulette Dávila; de Andrade Miranda, Ires Paula; Guillaumet, Jean-Louis; Pinto, Linder Felipe Mozombite; de Matos Bonates, Luiz Carlos; Silva, Natalino; Gómez, Ricardo Zárate; Zent, Stanford; Gonzales, Therany; Vos, Vincent A; Malhi, Yadvinder; Oliveira, Alexandre A; Cano, Angela; Albuquerque, Bianca Weiss; Vriesendorp, Corine; Correa, Diego Felipe; Torre, Emilio Vilanova; van der Heijden, Geertje; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Young, Kenneth R; Rocha, Maira; Nascimento, Marcelo Trindade; Medina, Maria Natalia Umaña; Tirado, Milton; Wang, Ophelia; Sierra, Rodrigo; Torres-Lezama, Armando; Mendoza, Casimiro; Ferreira, Cid; Baider, Cláudia; Villarroel, Daniel; Balslev, Henrik; Mesones, Italo; Giraldo, Ligia Estela Urrego; Casas, Luisa Fernanda; Reategui, Manuel Augusto Ahuite; Linares-Palomino, Reynaldo; Zagt, Roderick; Cárdenas, Sasha; Farfan-Rios, William; Sampaio, Adeilza Felipe; Pauletto, Daniela; Sandoval, Elvis H Valderrama; Arevalo, Freddy Ramirez; Huamantupa-Chuquimaco, Isau; Garcia-Cabrera, Karina; Hernandez, Lionel; Gamarra, Luis Valenzuela; Alexiades, Miguel N; Pansini, Susamar; Cuenca, Walter Palacios; Milliken, William; Ricardo, Joana; Lopez-Gonzalez, Gabriela; Pos, Edwin; Ter Steege, Hans

    2018-01-17

    Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large biodiversity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species' area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments.

  8. Microbial Distribution and Abundance in the Digestive System of Five Shipworm Species (Bivalvia: Teredinidae)

    Science.gov (United States)

    Betcher, Meghan A.; Fung, Jennifer M.; Han, Andrew W.; O’Connor, Roberta; Seronay, Romell; Concepcion, Gisela P.; Distel, Daniel L.; Haygood, Margo G.

    2012-01-01

    Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed. Here we use Fluorescence In-Situ Hybridization (FISH) and laser scanning confocal microscopy with 16S rRNA directed oligonucleotide probes targeting all domains, domains Bacteria and Archaea, and other taxonomic groups to examine the digestive microbiota of 17 specimens from 5 shipworm species (Bankia setacea, Lyrodus pedicellatus, Lyrodus massa, Lyrodus sp. and Teredo aff. triangularis). These data reveal that the caecum, a large sac-like appendage of the stomach that typically contains large quantities of wood particles and is considered the primary site of wood digestion, harbors only very sparse microbial populations. However, a significant number of bacterial cells were observed in fecal pellets within the intestines. These results suggest that due to low abundance, bacteria in the caecum may contribute little to lignocellulose degradation. In contrast, the comparatively high population density of bacteria in the intestine suggests a possible role for intestinal bacteria in the degradation of lignocellulose. PMID:23028923

  9. Macroinvertebrate abundance, water chemistry, and wetland characteristics affect use of wetlands by avian species in Maine

    Science.gov (United States)

    Longcore, J.R.; McAuley, D.G.; Pendelton, G.W.; Bennatti, C.R.; Mingo, T.M.; Stromborg, K.L.

    2006-01-01

    Our objective was to determine use by avian species (e.g., piscivores, marsh birds, waterfowl, selected passerines) of 29 wetlands in areas with low (chemistry, basin characteristics, and avian use of different wetland types. Shallow, beaver (Castor canadensis)-created wetlands with the highest phosphorus levels and abundant and varied macrophyte assemblages supported greater densities of macroinvertebrates and numbers of duck broods (88.3% of all broods) in contrast to deep, glacial type wetlands with sparse vegetation and lower invertebrate densities that supported fewer broods (11.7%). Low pH may have affected some acid-intolerant invertebrate taxa (i.e., Ephemeroptera), but high mean numbers of Insecta per wetland were recorded from wetlands with a pH of 5.51. Other Classes and Orders of invertebrates were more abundant on wetlands with pH > 5.51. All years combined use of wetlands by broods was greater on wetlands with pH ≤ 5.51 (77.4%) in contract to wetlands with pH > 5.51 that supported 21.8% of the broods. High mean brood density was associated with mean number of Insecta per wetland. For lentic wetlands created by beaver, those habitats contained vegetative structure and nutrients necessary to provide cover to support invertebrate populations that are prey of omnivore and insectivore species. The fishless status of a few wetlands may have affected use by some waterfowl species and obligate piscivores.

  10. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas.

    Directory of Open Access Journals (Sweden)

    Olga Heim

    Full Text Available Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany. Using spatial analysis (GIS, we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water. In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers. Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the

  11. Moth species richness, abundance and diversity in fragmented urban woodlands: implications for conservation and management strategies

    OpenAIRE

    Lintott, P.; Bunnefeld, N.; Fuentes-Montemayor, E.; Minderman, J.; Blackmore, L.; Goulson, D.; Park, K.

    2014-01-01

    Urban expansion threatens global biodiversity through the destruction of natural and semi-natural habitats and increased levels of disturbance. Whilst woodlands in urban areas may reduce the impact of urbanisation on biodiversity, they are often subject to under or over-management and consist of small, fragmented patches which may be isolated. Effective management strategies for urban woodland require an understanding of the\\ud ecology and habitat requirements of all relevant taxa. Yet, littl...

  12. TEMPERATURE AND PRECIPITATION AS PREDICTORS OF SPECIES RICHNESS IN NORTHERN ANDEAN AMPHIBIANS FROM COLOMBIA

    Directory of Open Access Journals (Sweden)

    Ortiz-Yusty Carlos Eduardo

    2013-07-01

    Full Text Available Our objective was to explore the spatial distribution patterns of amphibian speciesrichness in Antioquia, as model for the tropical Andes, and determine how annualmean temperature, annual precipitation, and elevation range influence it. We alsobriefly compare local and global regression models for estimating the relationbetween environmental variables and species richness. Distribution maps for 223amphibian species and environmental variables were generalized onto grid mapsof 752 blocks each covering the entire Department of Antioquia. We explored therelationship between species richness and environment using two global regressionmodels (the Ordinary Least Squares “OLS” and Generalized Linear Squares“GLS” models and one local model (the Geographically Weighted Regression“GWR” model. We found a significant relationship between species richness andenvironmental variables (GLS r2: 0.869; GRW r2: 0.929. The GLS model efficientlyincorporated the spatial autocorrelation effect and handled spatial dependencein the regression error terms while the GWR model showed the best fit (r2 andbalance between number of parameters and fit (AICc. GWR parameters show widevariation within the study area, indicating that relationship between species richnessand climate is spatially complex. Temperature was the most important variablein the GLS and GWR models, and altitude range the least significant. The strongrelationship between environment and amphibian richness is possibly due to lifehistory traits of amphibians, such as ectothermy and water dependency to completethe life cycle

  13. Seasonal variations of species composition and abundance of zooplankton in Ehoma Lake, a floodplain lake in Nigeria

    Directory of Open Access Journals (Sweden)

    Okechukwu. I Okogwu

    2010-03-01

    Full Text Available Ehoma Lake is among the important breeding sites of the major fishes in the Mid-Cross River, Nigeria. The juveniles of these fishes are solely dependent on zooplankton, which has not been studied previously. I studied monthly the lake’s physico-chemical variables and zooplankton composition in three stations (littoral, sub-littoral and pelagic from March 2005 to August 2006. Sixty-seven zooplankton species (42 rotifers, 19 cladocerans and 6 copepods were identified. Daphnia obtusa Kurz, Keratella valga Ehrenberg, Keratella ticinensis Callerrio, Keratella hiemalis Carlin, Brachionus dimidiatus Bryce and Lecane candida Hauer and Murray are new records for Nigeria. The dominant zooplankters were Diaphanosoma excisum Kurz and Moina micrura Kurz. There was an inverse relationship between species richness and abundance. Richness was highest in the dry season while peak zooplankton abundance was recorded in the rainy season. Zooplankton abundance and species richness decreased progressively from the littoral to the pelagic station while the Shannon-Weaver diversity index varied from 0.68 to 1.28 without a clear seasonal trend. There is a succession pattern: rotifers that are dominant in the dry season are replaced by cladocerans in the rainy season. This succession was greatly influenced by seasonal flooding of the lake. As no previous information on the zooplankton of the lake is available, this study provides baseline data on the lake`s zooplankton. Rev. Biol. Trop. 58 (1: 171-182. Epub 2010 March 01.El lago Ehoma, situado en la mitad del río Cross, es uno de los lugares de reproducción de las principales especies de peces del río. Los juveniles de estos peces dependen exclusivamente del zooplancton, sin embargo poco se sabe sobre este recurso en el lago. En este estudio, las variables físico-químicas y del zooplancton del lago fueron estudiadas mensualmente en tres estaciones (litoral, sub-litoral y pelágica, de marzo de 2005 a agosto de

  14. Assessing landscape constraints on species abundance: Does the neighborhood limit species response to local habitat conservation programs?

    Science.gov (United States)

    Jorgensen, Christopher F.; Powell, Larkin A.; Lusk, Jeffrey J.; Bishop, Andrew A.; Fontaine, Joseph J.

    2014-01-01

    Landscapes in agricultural systems continue to undergo significant change, and the loss of biodiversity is an ever-increasing threat. Although habitat restoration is beneficial, management actions do not always result in the desired outcome. Managers must understand why management actions fail; yet, past studies have focused on assessing habitat attributes at a single spatial scale, and often fail to consider the importance of ecological mechanisms that act across spatial scales. We located survey sites across southern Nebraska, USA and conducted point counts to estimate Ring-necked Pheasant abundance, an economically important species to the region, while simultaneously quantifying landscape effects using a geographic information system. To identify suitable areas for allocating limited management resources, we assessed land cover relationships to our counts using a Bayesian binomial-Poisson hierarchical model to construct predictive Species Distribution Models of relative abundance. Our results indicated that landscape scale land cover variables severely constrained or, alternatively, facilitated the positive effects of local land management for Ring-necked Pheasants.

  15. Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients

    Science.gov (United States)

    Spasojevic, Marko J.; Grace, James B.; Harrison, Susan; Damschen, Ellen Ingman

    2013-01-01

    1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic study by R. H. Whittaker (1960), herb species richness declined from mesic (cool, moist, northerly) slopes to xeric (hot, dry, southerly) slopes. Building on this dataset, we measured four plant functional traits (plant height, specific leaf area, leaf water content and foliar C:N) and used them to calculate three functional diversity metrics (functional richness, evenness, and dispersion). We then used a structural equation model to ask if ‘functional diversity’ (modeled as the joint responses of richness, evenness, and dispersion) could explain the observed relationship of topographic climate gradients to species richness. We then repeated our model examining the functional diversity of each of the four traits individually. 3. Consistent with the physiological tolerance hypothesis, we found that functional diversity was higher in more favorable climatic conditions (mesic slopes), and that multivariate functional diversity mediated the relationship of the topographic climate gradient to plant species richness. We found similar patterns for models focusing on individual trait functional diversity of leaf water content and foliar C:N. 4. Synthesis. Our results provide trait-based support for the physiological tolerance hypothesis, suggesting that benign climates support more species because they allow for a wider range of functional strategies.

  16. Beneath the veil: Plant growth form influences the strength of species richness-productivity relationships in forests

    Science.gov (United States)

    Oberle, B.; Grace, J.B.; Chase, J.M.

    2009-01-01

    Aim: Species richness has been observed to increase with productivity at large spatial scales, though the strength of this relationship varies among functional groups. In forests, canopy trees shade understorey plants, and for this reason we hypothesize that species richness of canopy trees will depend on macroclimate, while species richness of shorter growth forms will additionally be affected by shading from the canopy. In this study we test for differences in species richness-productivity relationships (SRPRs) among growth forms (canopy trees, shrubs, herbaceous species) in small forest plots. Location: We analysed 231 plots ranging from 34.0?? to 48.3?? N latitude and from 75.0?? to 124.2?? W longitude in the United States. Methods: We analysed data collected by the USDA Forest Inventory and Analysis program for plant species richness partitioned into different growth forms, in small plots. We used actual evapotranspiration as a macroclimatic estimate of regional productivity and calculated the area of light-blocking tissue in the immediate area surrounding plots for an estimate of the intensity of local shading. We estimated and compared SRPRs for different partitions of the species richness dataset using generalized linear models and we incorporated the possible indirect effects of shading using a structural equation model. Results: Canopy tree species richness increased strongly with regional productivity, while local shading primarily explained the variation in herbaceous plant richness. Shrub species richness was related to both regional productivity and local shading. Main conclusions: The relationship between total forest plant species richness and productivity at large scales belies strong effects of local interactions. Counter to the pattern for overall richness, we found that understorey herbaceous plant species richness does not respond to regional productivity gradients, and instead is strongly influenced by canopy density, while shrub species

  17. Evaluating functional diversity: Missing trait data and the importance of species abundance structure and data transformation

    Czech Academy of Sciences Publication Activity Database

    Májeková, M.; Paal, T.; Plowman, Nichola S.; Bryndová, Michala; Kasari, L.; Norberg, A.; Weiss, Matthias; Bishop, T. R.; Luke, S. H.; Sam, Kateřina; Le Bagousse-Pinguet, Y.; Lepš, Jan; Götzenberger, Lars; de Bello, Francesco

    2016-01-01

    Roč. 11, č. 2 (2016), č. článku e0149270. E-ISSN 1932-6203 R&D Projects: GA ČR GB14-36098G; GA ČR(CZ) GP14-32024P; GA ČR GAP505/12/1296 Grant - others:GA JU(CZ) 156/2013/P Institutional support: RVO:60077344 ; RVO:67985939 Keywords : data incompleteness * functional diversity * species abundance Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (BU-J) Impact factor: 2.806, year: 2016 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149270

  18. Richness and abundance of the cardini group of Drosophila (Diptera, Drosophilidae) in the Caatinga and Atlantic Forest biomes in northeastern Brazil.

    Science.gov (United States)

    Rohde, Cláudia; Silva, Diva Maria Izabel O; Oliveira, Geórgia F; Monteiro, Liv S; Montes, Martín A; Garcia, Ana Cristina L

    2014-12-01

    Brazil has a high diversity of flies of the genus Drosophila, and part of this richness is represented by the cardini group. We analyzed the fluctuations in the richness and abundance of this group, in environments that had never previously been studied in the northeastern region of Brazil. Among the 28,204 drosophilids sampled, 1,294 belonged to the cardini group and were represented by D. polymorpha, D. cardini, D. neocardini and D. cardinoides. Occurrences of D. neocardini and D. cardinoides were registered for the first time in the Caatinga. In this biome, D. cardini stood out as having the highest abundance, and D. polymorpha was not observed. In the coastal Atlantic Forest, D. cardini was not registered, but D. polymorpha was found in all the localities investigated. Mangrove swamps were the environment with the lowest abundance and richness of the cardini group. The High-altitude Forest presented the highest richness of this group. We suggest that the high abundance of D. polymorpha in the High-altitude Forest and in the coastal Atlantic Forest may be a reflection of the historical relationship between these two environments.

  19. Vascular plant species richness along environmental gradients in a cool temperate to sub-alpine mountainous zone in central Japan.

    Science.gov (United States)

    Tsujino, Riyou; Yumoto, Takakazu

    2013-03-01

    In order to clarify how vegetation types change along the environmental gradients in a cool temperate to sub-alpine mountainous zone and the determinant factors that define plant species richness, we established 360 plots (each 4 × 10 m) within which the vegetation type, species richness, elevation, topographic position index (TPI), slope inclination, and ground light index (GLI) of the natural vegetation were surveyed. Mean elevation, TPI, slope inclination, and GLI differed across vegetation types. Tree species richness was negatively correlated with elevation, whereas fern and herb species richness were positively correlated. Tree species richness was greater in the upper slope area than the lower slope area, whereas fern and herb species richness were greater in the lower slope area. Ferns and trees species richness were smaller in the open canopy, whereas herb species richness was greater in the open canopy. Vegetation types were determined firstly by elevation and secondary by topographic configurations, such as topographic position, and slope inclination. Elevation and topography were the most important factors affecting plant richness, but the most influential variables differed among plant life-form groups. Moreover, the species richness responses to these environmental gradients greatly differed among ferns, herbs, and trees.

  20. Does residence time affect responses of alien species richness to environmental and spatial processes?

    Directory of Open Access Journals (Sweden)

    Matteo Dainese

    2012-08-01

    Full Text Available One of the most robust emerging generalisations in invasion biology is that the probability of invasion increases with the time since introduction (residence time. We analysed the spatial distribution of alien vascular plant species in a region of north-eastern Italy to understand the influence of residence time on patterns of alien species richness. Neophytes were grouped according to three periods of arrival in the study region (1500–1800, 1800–1900, and > 1900. We applied multiple regression (spatial and non-spatial with hierarchical partitioning to determine the influence of climate and human pressure on species richness within the groups. We also applied variation partitioning to evaluate the relative importance of environmental and spatial processes. Temperature mainly influenced groups with speciesa longer residence time, while human pressure influenced the more recently introduced species, although its influence remained significant in all groups. Partial regression analyses showed that most of the variation explained by the models is attributable to spatially structured environmental variation, while environment and space had small independent effects. However, effects independent of environment decreased, and spatially independent effects increased, from older to the more recent neophytes. Our data illustrate that the distribution of alien species richness for species that arrived recently is related to propagule pressure, availability of novel niches created by human activity, and neutral-based (dispersal limitation processes, while climate filtering plays a key role in the distribution of species that arrived earlier. This study highlights the importance of residence time, spatial structure, and environmental conditions in the patterns of alien species richness and for a better understanding of its geographical variation.

  1. Aligning conservation goals: are patterns of species richness and endemism concordant at regional scales?

    Directory of Open Access Journals (Sweden)

    Ricketts, T. H.

    2001-01-01

    Full Text Available Biodiversity conservation strategies commonly target areas of high species richness and/or high endemism. However, the correlation between richness and endemism at scales relevant to conservation is unclear; these two common goals of conservation plans may therefore be in conflict. Here the spatial concordance between richness and endemism is tested using five taxa in North America: butterflies, birds, mammals, amphibians, and reptiles. This concordance is also tested using overall indices of richness and endemism (incorporating all five taxa. For all taxa except birds, richness and endemism were significantly correlated, with amphibians, reptiles, and the overall indices showing the highest correlations (rs = 0.527-0.676. However, 'priority sets' of ecoregions (i.e., the top 10% of ecoregions based on richness generally overlapped poorly with those based on endemism (< 50% overlap for all but reptiles. These results offer only limited support for the idea that richness and endemism are correlated at broad scales and indicate that land managers will need to balance these dual, and often conflicting, goals of biodiversity conservation.

  2. Metazoan parasite species richness in Neotropical fishes: hotspots and the geography of biodiversity.

    Science.gov (United States)

    Luque, J L; Poulin, R

    2007-06-01

    Although research on parasite biodiversity has intensified recently, there are signs that parasites remain an underestimated component of total biodiversity in many regions of the planet. To identify geographical hotspots of parasite diversity, we performed qualitative and quantitative analyses of the parasite-host associations in fishes from Latin America and the Caribbean, a region that includes known hotspots of plant and animal biodiversity. The database included 10,904 metazoan parasite-host associations involving 1660 fish species. The number of host species with at least 1 parasite record was less than 10% of the total known fish species in the majority of countries. Associations involving adult endoparasites in actinopterygian fish hosts dominated the database. Across the whole region, no significant difference in parasite species richness was detected between marine and freshwater fishes. As a rule, host body size and study effort (number of studies per fish species) were good predictors of parasite species richness. Some interesting patterns emerged when we included only the regions with highest fish species biodiversity and study effort (Brazil, Mexico and the Caribbean Islands). Independently of differences in study effort or host body sizes, Mexico stands out as a hotspot of parasite diversity for freshwater fishes, as does Brasil for marine fishes. However, among 57 marine fish species common to all 3 regions, populations from the Caribbean consistently harboured more parasite species. These differences may reflect true biological patterns, or regional discrepancies in study effort and local priorities for fish parasitology research.

  3. Organic, integrated and conventional management in apple orchards: effect on plant species composition, richness and diversity

    Directory of Open Access Journals (Sweden)

    Zdeňka Lososová

    2011-01-01

    Full Text Available The study was conducted to assess the effect of conventional, integrated and organic management on differences in plant species composition, richness and diversity. The plants were studied in triads of orchards situated in three regions of the Czech Republic. Data about species occurrences were collected on 15 permanent plots in the tree rows and 15 plots between tree rows in each of the apple orchards during 2009. A total of 201 vascular plant species (127 native species, 65 archaeophytes, and 9 neophytes were found. Management type and also different regional conditions had a significant effect on plant species composition and on diversity parameters of orchard spontaneous vegetation. Species richness and species pool was significantly higher in the organic orchards than in the differently managed orchards. Management type had significant effect on proportions of archaeophytes, and also neophytes in apple orchards. The results showed that a change from conventional to integrated and organic management in apple orchards lead to higher plant species diversity and to changes in plant species composition.

  4. Determinants of bird species richness, endemism, and island network roles in Wallacea and the West Indies

    DEFF Research Database (Denmark)

    Dalsgaard, Bo; Carstensen, Daniel Wisbech; Fjeldså, Jon

    2014-01-01

    , and network roles indicates that historical climate had little effects on extinction-immigration dynamics. This is in contrast to the strong effect of historical climate observed on the mainland, possibly because surrounding oceans buffer against strong climate oscillations and because geography is a strong....... Here, we evaluate the potential additional effects of historical climate on breeding land bird richness and endemism in Wallacea and the West Indies. Furthermore, on the basis of species distributions, we identify island biogeographical network roles and examine their association with geography......, current and historical climate, and bird richness/endemism. We found that island geography, especially island area but also isolation and elevation, largely explained the variation in island species richness and endemism. Current and historical climate only added marginally to our understanding...

  5. The importance of plot size and the number of sampling seasons on capturing macrofungal species richness.

    Science.gov (United States)

    Li, Huili; Ostermann, Anne; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D; Mortimer, Peter E

    2018-07-01

    The species-area relationship is an important factor in the study of species diversity, conservation biology, and landscape ecology. A deeper understanding of this relationship is necessary, in order to provide recommendations on how to improve the quality of data collection on macrofungal diversity in different land use systems in future studies, a systematic assessment of methodological parameters, in particular optimal plot sizes. The species-area relationship of macrofungi in tropical and temperate climatic zones and four different land use systems were investigated by determining the macrofungal species richness in plot sizes ranging from 100 m 2 to 10 000 m 2 over two sampling seasons. We found that the effect of plot size on recorded species richness significantly differed between land use systems with the exception of monoculture systems. For both climate zones, land use system needs to be considered when determining optimal plot size. Using an optimal plot size was more important than temporal replication (over two sampling seasons) in accurately recording species richness. Copyright © 2018 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  6. No evidence of complementary water use along a plant species richness gradient in temperate experimental grasslands.

    Directory of Open Access Journals (Sweden)

    Dörte Bachmann

    Full Text Available Niche complementarity in resource use has been proposed as a key mechanism to explain the positive effects of increasing plant species richness on ecosystem processes, in particular on primary productivity. Since hardly any information is available for niche complementarity in water use, we tested the effects of plant diversity on spatial and temporal complementarity in water uptake in experimental grasslands by using stable water isotopes. We hypothesized that water uptake from deeper soil depths increases in more diverse compared to low diverse plant species mixtures. We labeled soil water in 8 cm (with 18O and 28 cm depth (with ²H three times during the 2011 growing season in 40 temperate grassland communities of varying species richness (2, 4, 8 and 16 species and functional group number and composition (legumes, grasses, tall herbs, small herbs. Stable isotope analyses of xylem and soil water allowed identifying the preferential depth of water uptake. Higher enrichment in 18O of xylem water than in ²H suggested that the main water uptake was in the upper soil layer. Furthermore, our results revealed no differences in root water uptake among communities with different species richness, different number of functional groups or with time. Thus, our results do not support the hypothesis of increased complementarity in water use in more diverse than in less diverse communities of temperate grassland species.

  7. Drivers of inter-annual variation and long-term change in High-Arctic spider species abundances

    DEFF Research Database (Denmark)

    Bowden, Joseph J.; Hansen, Oskar L. P.; Olsen, Kent

    2018-01-01

    Understanding how species abundances vary in space and time is a central theme in ecology, yet there are few long-term field studies of terrestrial invertebrate abundances and the determinants of their dynamics. This is particularly relevant in the context of rapid climate change occurring...... in the Arctic. Arthropods can serve as strong indicators of ecosystem change due to their sensitivity to increasing temperatures and other environmental variables. We used spider samples collected by pitfall trapping from three different habitats (fen, mesic and arid heath) in High-Arctic Greenland to assess...... interpretation of long-term trends. We used model selection to determine which climatic variables and/or previous years’ abundance best explained annual variation in species abundances over this period. We identified and used 28 566 adult spiders that comprised eight species. Most notably, the abundances of some...

  8. A global evaluation of metabolic theory as an explanation for terrestrial species richness gradients

    DEFF Research Database (Denmark)

    Hawkins, Bradford A.; Albuquerque, Fabio S.; Araújo, Miguel B.

    2007-01-01

    We compiled 46 broadscale data sets of species richness for a wide range of terrestrial plant, invertebrate, and ectothermic vertebrate groups in all parts of the world to test the ability of metabolic theory to account for observed diversity gradients. The theory makes two related predictions: (...

  9. Using Google Earth Surface Metrics to Predict Plant Species Richness in a Complex Landscape

    Directory of Open Access Journals (Sweden)

    Sebastián Block

    2016-10-01

    Full Text Available Google Earth provides a freely available, global mosaic of high-resolution imagery from different sensors that has become popular in environmental and ecological studies. However, such imagery lacks the near-infrared band often used in studying vegetation, thus its potential for estimating vegetation properties remains unclear. In this study, we assess the potential of Google Earth imagery to describe and predict vegetation attributes. Further, we compare it to the potential of SPOT imagery, which has additional spectral information. We measured basal area, vegetation height, crown cover, density of individuals, and species richness in 60 plots in the oak forests of a complex volcanic landscape in central Mexico. We modelled each vegetation attribute as a function of surface metrics derived from Google Earth and SPOT images, and selected the best-supported linear models from each source. Total species richness was the best-described and predicted variable: the best Google Earth-based model explained nearly as much variation in species richness as its SPOT counterpart (R2 = 0.44 and 0.51, respectively. However, Google Earth metrics emerged as poor predictors of all remaining vegetation attributes, whilst SPOT metrics showed potential for predicting vegetation height. We conclude that Google Earth imagery can be used to estimate species richness in complex landscapes. As it is freely available, Google Earth can broaden the use of remote sensing by researchers and managers in low-income tropical countries where most biodiversity hotspots are found.

  10. Moisture and nutrients determine the distribution and richness of India's large herbivore species assemblage

    NARCIS (Netherlands)

    Ahrestani, F.S.; Heitkonig, I.M.A.; Langevelde, van F.; Vaidyanathan, S.; Madhusudan, M.D.; Prins, H.H.T.

    2011-01-01

    The goal of this study was to test whether body-mass based foraging principles, guided by plant available moisture (PAM) and plant available nutrients (PAN), could explain large mammalian herbivore species distribution and richness in India. We tested (1) whether the occurrence of larger-bodied

  11. Changes in biomass allocation in species rich meadow after abandonment: Ecological strategy or allometry?

    Czech Academy of Sciences Publication Activity Database

    Bartušková, Alena; Doležal, Jiří; Janeček, Štěpán; Lanta, V.; Klimešová, Jitka

    2015-01-01

    Roč. 17, č. 5 (2015), s. 379-387 ISSN 1433-8319 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : Biomass allocation * species-rich meadow * abandonment Subject RIV: EF - Botanics Impact factor: 3.578, year: 2015

  12. Species richness and origin of the bryophyte flora of the Colombian Andes

    NARCIS (Netherlands)

    Gradstein, S.R.; Reenen, van G.B.A.; Griffin, D.

    1988-01-01

    Based on data from the ECOANDES project, a phytogeographical analysis has been made of the bryophyte flora along the wet, foggy western slope (1000-4500 m) and the drier eastern slope (500-4500 m) of the Colombian Central Cordillera at the ‘Parque de los Nevados’. Species richness increases with

  13. Carrying capacity for species richness as context for conservation: a case study of North American birds

    Science.gov (United States)

    Andrew J. Hansen; Linda Bowers Phillips; Curtis H. Flather; Jim Robinson-Cox

    2011-01-01

    We evaluated the leading hypotheses on biophysical factors affecting species richness for Breeding Bird Survey routes from areas with little influence of human activities.We then derived a best model based on information theory, and used this model to extrapolate SK across North America based on the biophysical predictor variables. The predictor variables included the...

  14. Impact of Precipitation Patterns on Biomass and Species Richness of Annuals in a Dry Steppe

    Science.gov (United States)

    Yan, Hong; Liang, Cunzhu; Li, Zhiyong; Liu, Zhongling; Miao, Bailing; He, Chunguang; Sheng, Lianxi

    2015-01-01

    Annuals are an important component part of plant communities in arid and semiarid grassland ecosystems. Although it is well known that precipitation has a significant impact on productivity and species richness of community or perennials, nevertheless, due to lack of measurements, especially long-term experiment data, there is little information on how quantity and patterns of precipitation affect similar attributes of annuals. This study addresses this knowledge gap by analyzing how quantity and temporal patterns of precipitation affect aboveground biomass, interannual variation aboveground biomass, relative aboveground biomass, and species richness of annuals using a 29-year dataset from a dry steppe site at the Inner Mongolia Grassland Ecosystem Research Station. Results showed that aboveground biomass and relative aboveground biomass of annuals increased with increasing precipitation. The coefficient of variation in aboveground biomass of annuals decreased significantly with increasing annual and growing-season precipitation. Species richness of annuals increased significantly with increasing annual precipitation and growing-season precipitation. Overall, this study highlights the importance of precipitation for aboveground biomass and species richness of annuals. PMID:25906187

  15. Species diversity and richness of wild birds in Dagona-Waterfowl ...

    African Journals Online (AJOL)

    The study of bird species diversity and richness in Dagona-Waterfowl Sanctuary was carried out during the midst of both early wet and late dry seasons, to provide comprehensive data on wild birds. Dagona Sanctuary is located within the Bade-Nguru Wetland sector. It is one of the important bird areas marked for the ...

  16. Species richness and composition assessment of spiders in a Mediterranean scrubland

    DEFF Research Database (Denmark)

    Bondoso Cardoso, Pedro Miguel; Henriques, Sérgio S.; Gaspar, Clara

    2009-01-01

    Intensive fieldwork has been undertaken in Portugal in order to develop a standardized and optimized sampling protocol for Mediterranean spiders. The present study had the objectives of testing the use of semi-quantitative sampling for obtaining an exhaustive species richness assessment of spiders...

  17. Managed forest landscape structure and avian species richness in the southeastern US

    Science.gov (United States)

    Craig Loehle; T. Bently Wigley; Scott Rutzmoser; John A. Gerwin; Patrick D. Keyser; Richard A. Lancia; Christopher J. Reynolds; Ronald E. Thill; Robert Weih; Don White; Petra Bohall Wood

    2005-01-01

    Forest structural features at the stand scale (e.g., snags, stem density, species composition) and habitat attributes at larger spatial scales (e.g., landscape pattern, road density) can influence biological diversity and have been proposed as indicators in sustainable forestry programs. This study investigated relationships between such factors and total richness of...

  18. Patterns in species richness and distribution of vascular epiphytes in Chiapas, Mexico

    NARCIS (Netherlands)

    Wolf, J.H.D.; Flamenco-S., A.

    2003-01-01

    Aim We aim to assess regional patterns in the distribution and species richness of vascular epiphytes with an emphasis on forests that differ in altitude and the amount of rainfall. Location Tropical America, in particularly the 75000 km2 large state of Chiapas in southern Mexico at 14.5-18.0º N.

  19. Quantifying establishment limitations during the ecological restoration of species-rich Nardus grassland

    NARCIS (Netherlands)

    Daele, Van Frederik; Wasof, Safaa; Demey, Andreas; Schelfhout, Stephanie; Schrijver, De A.; Baeten, Lander; Ruijven, van Jasper; Mertens, Jan; Verheyen, Kris

    2017-01-01

    Aims: Successful establishment of species-rich Nardus grasslands on ex-agricultural land requires identification and removal of barriers to effective seed germination and seedling survival. Therefore, we investigate how germination and early development are affected by soil conditions from

  20. Reef flattening effects on total richness and species responses in the Caribbean

    NARCIS (Netherlands)

    Newman, Steven P.; Meesters, E.H.; Dryden, Charlie S.; Williams, Stacey M.; Sanchez, Cristina; Mumby, Peter J.; Polunin, Nicholas V.C.

    2015-01-01

    There has been ongoing flattening of Caribbean coral reefs with the loss of habitat having severe implications for these systems. Complexity and its structural components are important to fish species richness and community composition, but little is known about its role for other taxa or

  1. Model uncertainties do not affect observed patterns of species richness in the Amazon

    Science.gov (United States)

    Sales, Lilian Patrícia; Neves, Olívia Viana; De Marco, Paulo

    2017-01-01

    Background Climate change is arguably a major threat to biodiversity conservation and there are several methods to assess its impacts on species potential distribution. Yet the extent to which different approaches on species distribution modeling affect species richness patterns at biogeographical scale is however unaddressed in literature. In this paper, we verified if the expected responses to climate change in biogeographical scale—patterns of species richness and species vulnerability to climate change—are affected by the inputs used to model and project species distribution. Methods We modeled the distribution of 288 vertebrate species (amphibians, birds and mammals), all endemic to the Amazon basin, using different combinations of the following inputs known to affect the outcome of species distribution models (SDMs): 1) biological data type, 2) modeling methods, 3) greenhouse gas emission scenarios and 4) climate forecasts. We calculated uncertainty with a hierarchical ANOVA in which those different inputs were considered factors. Results The greatest source of variation was the modeling method. Model performance interacted with data type and modeling method. Absolute values of variation on suitable climate area were not equal among predictions, but some biological patterns were still consistent. All models predicted losses on the area that is climatically suitable for species, especially for amphibians and primates. All models also indicated a current East-western gradient on endemic species richness, from the Andes foot downstream the Amazon river. Again, all models predicted future movements of species upwards the Andes mountains and overall species richness losses. Conclusions From a methodological perspective, our work highlights that SDMs are a useful tool for assessing impacts of climate change on biodiversity. Uncertainty exists but biological patterns are still evident at large spatial scales. As modeling methods are the greatest source of

  2. Connectivity and conditional models of access and abundance of species in stream networks.

    Science.gov (United States)

    Chelgren, Nathan D; Dunham, Jason B

    2015-07-01

    Barriers to passage of aquatic organisms at stream road crossings are a major cause of habitat fragmentation in stream networks. Accordingly, large investments have been made to restore passage at these crossings, but often without estimation of population-level benefits. Here, we describe a broad-scale approach to quantifying the effectiveness of passage restoration in terms interpretable at population levels, namely numbers of fish and length of stream gained through restoration, by sampling abundance in a study design that accounts for variable biogeographic species pools, variable stream and barrier configurations, and variable probabilities of capture and detectability for multiple species. We modified an existing zero-inflated negative-binomial model to estimate the probability of site access, abundance conditional on access, and capture probability of individual fish. Therein, we modeled probability of access as a function of gradient, stream road-crossing type, and downstream access by fish simultaneously with a predictive model for abundance at sites accessible to fish. Results indicated that replacement of barriers with new crossing designs intended to allow for greater movement was associated with dramatically higher probability of access for all fishes, including migratory Pacific salmon, trout, sculpin, and lamprey. Conversely, existing non-replaced crossings negatively impacted fish distributions. Assuming no downstream constraints on access, we estimated the potential length of stream restored by the program ranged between 7.33 (lamprey) and 15.28 km (small coastal cutthroat and rainbow trout). These contributions represented a fraction of the total length available upstream (187 km) of replaced crossings. When limited ranges of species were considered, the estimated contributions of culvert replacement were reduced (1.65-km range, for longnose dace to 12.31 km for small coastal cutthroat and rainbow trout). Numbers of fish contributed ranged from

  3. The effects of global change on the distribution, species richness and life history of European dragonflies

    DEFF Research Database (Denmark)

    Olsen, Kent

    2016-01-01

    traits such as taxonomy, habitat specificity, metabolic plasticity, and biogeographic traits such zoogeographical origin. In Paper I we describe how changes in species richness pattern across Europe correlate with range changes in different taxonomic and biogeographic groups of dragonflies. We found...... specialized species adapted to permanent running (perennial lotic) water habitats. We found that species reproducing in temporary water track climate changes better than species adapted to permanent water. In Paper III we explore the relationship between metabolic plasticity (expressed as the ability to shift...... with less metabolic plasticity. We conducted experimental ex-situ measurements of metabolic rates measured as respiration rates at 10°C and 20°C, respectively, of four Scandinavian dragonfly species. We used two species with a northern distribution, one with a southern distribution and one ubiquitous...

  4. Plant DNA barcodes can accurately estimate species richness in poorly known floras.

    Directory of Open Access Journals (Sweden)

    Craig Costion

    Full Text Available BACKGROUND: Widespread uptake of DNA barcoding technology for vascular plants has been slow due to the relatively poor resolution of species discrimination (∼70% and low sequencing and amplification success of one of the two official barcoding loci, matK. Studies to date have mostly focused on finding a solution to these intrinsic limitations of the markers, rather than posing questions that can maximize the utility of DNA barcodes for plants with the current technology. METHODOLOGY/PRINCIPAL FINDINGS: Here we test the ability of plant DNA barcodes using the two official barcoding loci, rbcLa and matK, plus an alternative barcoding locus, trnH-psbA, to estimate the species diversity of trees in a tropical rainforest plot. Species discrimination accuracy was similar to findings from previous studies but species richness estimation accuracy proved higher, up to 89%. All combinations which included the trnH-psbA locus performed better at both species discrimination and richness estimation than matK, which showed little enhanced species discriminatory power when concatenated with rbcLa. The utility of the trnH-psbA locus is limited however, by the occurrence of intraspecific variation observed in some angiosperm families to occur as an inversion that obscures the monophyly of species. CONCLUSIONS/SIGNIFICANCE: We demonstrate for the first time, using a case study, the potential of plant DNA barcodes for the rapid estimation of species richness in taxonomically poorly known areas or cryptic populations revealing a powerful new tool for rapid biodiversity assessment. The combination of the rbcLa and trnH-psbA loci performed better for this purpose than any two-locus combination that included matK. We show that although DNA barcodes fail to discriminate all species of plants, new perspectives and methods on biodiversity value and quantification may overshadow some of these shortcomings by applying barcode data in new ways.

  5. Plant DNA barcodes can accurately estimate species richness in poorly known floras.

    Science.gov (United States)

    Costion, Craig; Ford, Andrew; Cross, Hugh; Crayn, Darren; Harrington, Mark; Lowe, Andrew

    2011-01-01

    Widespread uptake of DNA barcoding technology for vascular plants has been slow due to the relatively poor resolution of species discrimination (∼70%) and low sequencing and amplification success of one of the two official barcoding loci, matK. Studies to date have mostly focused on finding a solution to these intrinsic limitations of the markers, rather than posing questions that can maximize the utility of DNA barcodes for plants with the current technology. Here we test the ability of plant DNA barcodes using the two official barcoding loci, rbcLa and matK, plus an alternative barcoding locus, trnH-psbA, to estimate the species diversity of trees in a tropical rainforest plot. Species discrimination accuracy was similar to findings from previous studies but species richness estimation accuracy proved higher, up to 89%. All combinations which included the trnH-psbA locus performed better at both species discrimination and richness estimation than matK, which showed little enhanced species discriminatory power when concatenated with rbcLa. The utility of the trnH-psbA locus is limited however, by the occurrence of intraspecific variation observed in some angiosperm families to occur as an inversion that obscures the monophyly of species. We demonstrate for the first time, using a case study, the potential of plant DNA barcodes for the rapid estimation of species richness in taxonomically poorly known areas or cryptic populations revealing a powerful new tool for rapid biodiversity assessment. The combination of the rbcLa and trnH-psbA loci performed better for this purpose than any two-locus combination that included matK. We show that although DNA barcodes fail to discriminate all species of plants, new perspectives and methods on biodiversity value and quantification may overshadow some of these shortcomings by applying barcode data in new ways.

  6. Blackflies (Diptera: Simuliidae) in Croatia: species richness, distribution and relationship to surrounding countries.

    Science.gov (United States)

    Ivković, Marija; Kúdela, Matuš; Kúdelová, Tatiana

    2016-05-05

    All records of blackflies (Simuliidae) from the territory of Croatia are summarized, including previously unpublished data. The blackfly fauna of Croatia consists of 28 species. Simulium (Nevermannia) angustitarse (Lundström), Simulium (Nevermannia) cryophilum (Rubtsov) complex, Simulium (Nevermannia) lundstromi (Enderlein), Simulium (Nevermannia) vernum Macquart complex, Simulium (Simulium) argyreatum Meigen, Simulium (Simulium) bezzii (Corti) complex, Simulium paraequinum Puri and Simulium pseudequinum Séguy are reported for the first time from Croatia. Information related to the ecoregions, in which species were found and specific species traits are given. Genus Prosimulium Roubaud is represented by one species only. Genus Simulium Latreille is represented by 27 species in six subgenera, with subgenus Simulium Latreille s. str. being most species rich (13 species) and subgenera Boophthora Enderlein and  Trichodagmia Enderlein represented each by only one species. Compared to the neighboring countries, the Croatian species assemblage is most similar to the fauna of Slovenia and least similar to that of Italy. The relatively low number of species, presence of several species complexes and unclear identity of other species show that further research of blackflies in Croatia is needed.

  7. MESSENGER Searches for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

    Science.gov (United States)

    Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos

    2011-01-01

    Mercury's exosphere is composed of material that originates at the planet's surface, whether that material is native or delivered by the solar wind and micrometeoroids. Many exospheric species have been detected by remote sensing, including H and He by Mariner 10, Na, K, and Ca by ground-based observations, and H, Na, Ca, Mg, and Ca+ by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Other exospheric species, including Fe, AI, Si, 0, S, Mn, CI, Ti, OH, and their ions, are expected to be present on the basis of MESSENGER surface measurements and models of Mercury's surface chemistry. Here we report on searches for these species made with the Ultraviolet and Visible Spectrometer (UVVS) channel of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS). No obvious signatures of the listed species have yet been observed in Mercury's exosphere by the UVVS as of this writing. It is possible that detections are elusive because the optimum regions of the exosphere have not been sampled. The Sun-avoidance constraints on MESSENGER place tight limits on instrument boresight directions, and some regions are probed infrequently. If there are strong spatial gradients in the distribution of weakly emitting species, a high-resolution sampling of specific regions may be required to detect them. Summing spectra over time will also aid in the ability to detect weaker emission. Observations to date nonetheless permit strong upper limits to be placed on the abundances of many undetected species, in some cases as functions of time and space. As those limits are lowered with time, the absence of detections can provide insight into surface composition and the potential source mechanisms of exospheric material.

  8. Higher taxa as surrogates of species richness of spiders in insect-resistant transgenic rice

    Institute of Scientific and Technical Information of China (English)

    Sheng Lin; Min-Sheng You; Liette Vasseur; Guang Yang; Feng-Jing Liu; Feng Guo

    2012-01-01

    Biodiversity assessments can often be time- and resource-consuming.Several alternative approaches have been proposed to reduce sampling efforts,including indicator taxa and surrogates.In this study,we examine the reliability of higher taxon surrogates to predict species richness in two experimental rice fields of Fujian Province,southeastern China during 2005 and 2009.Spider samples in transgenic and nontransgenic plots were collected using a suction sampler.Both the genus and family surrogates had significant and positive linear relationships with species richness in the transgenic and nontransgenic rice fields.The rice varieties did not significantly influence the linear relationships.Our findings suggest that higher-taxon surrogacy could be a useful alternative to complete species inventory for risk assessments of transgenic rice.

  9. Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments

    Science.gov (United States)

    Yang, Sizhong; Wen, Xi; Shi, Yulan; Liebner, Susanne; Jin, Huijun; Perfumo, Amedea

    2016-01-01

    Oil spills from pipeline ruptures are a major source of terrestrial petroleum pollution in cold regions. However, our knowledge of the bacterial response to crude oil contamination in cold regions remains to be further expanded, especially in terms of community shifts and potential development of hydrocarbon degraders. In this study we investigated changes of microbial diversity, population size and keystone taxa in permafrost soils at four different sites along the China-Russia crude oil pipeline prior to and after perturbation with crude oil. We found that crude oil caused a decrease of cell numbers together with a reduction of the species richness and shifts in the dominant phylotypes, while bacterial community diversity was highly site-specific after exposure to crude oil, reflecting different environmental conditions. Keystone taxa that strongly co-occurred were found to form networks based on trophic interactions, that is co-metabolism regarding degradation of hydrocarbons (in contaminated samples) or syntrophic carbon cycling (in uncontaminated samples). With this study we demonstrate that after severe crude oil contamination a rapid establishment of endemic hydrocarbon degrading communities takes place under favorable temperature conditions. Therefore, both endemism and trophic correlations of bacterial degraders need to be considered in order to develop effective cleanup strategies. PMID:27886221

  10. Geographical, Temporal and Environmental Determinants of Bryophyte Species Richness in the Macaronesian Islands

    Science.gov (United States)

    Aranda, Silvia C.; Gabriel, Rosalina; Borges, Paulo A. V.; Santos, Ana M. C.; de Azevedo, Eduardo Brito; Patiño, Jairo; Hortal, Joaquín; Lobo, Jorge M.

    2014-01-01

    Species richness on oceanic islands has been related to a series of ecological factors including island size and isolation (i.e. the Equilibrium Model of Island Biogeography, EMIB), habitat diversity, climate (i.e., temperature and precipitation) and more recently island ontogeny (i.e. the General Dynamic Model of oceanic island biogeography, GDM). Here we evaluate the relationship of these factors with the diversity of bryophytes in the Macaronesian region (Azores, Madeira, Canary Islands and Cape Verde). The predictive power of EMIB, habitat diversity, climate and the GDM on total bryophyte richness, as well as moss and liverwort richness (the two dominant bryophyte groups), was evaluated through ordinary least squares regressions. After choosing the best subset of variables using inference statistics, we used partial regression analyses to identify the independent and shared effects of each model. The variables included within each model were similar for mosses and liverworts, with orographic mist layer being one of the most important predictors of richness. Models combining climate with either the GDM or habitat diversity explained most of richness variation (up to 91%). There was a high portion of shared variance between all pairwise combinations of factors in mosses, while in liverworts around half of the variability in species richness was accounted for exclusively by climate. Our results suggest that the effects of climate and habitat are strong and prevalent in this region, while geographical factors have limited influence on Macaronesian bryophyte diversity. Although climate is of great importance for liverwort richness, in mosses its effect is similar to or, at least, indiscernible from the effect of habitat diversity and, strikingly, the effect of island ontogeny. These results indicate that for highly vagile taxa on oceanic islands, the dispersal process may be less important for successful colonization than the availability of suitable ecological

  11. Does plant species richness guarantee the resilience of local medical systems? A perspective from utilitarian redundancy.

    Directory of Open Access Journals (Sweden)

    Flávia Rosa Santoro

    Full Text Available Resilience is related to the ability of a system to adjust to disturbances. The Utilitarian Redundancy Model has emerged as a tool for investigating the resilience of local medical systems. The model determines the use of species richness for the same therapeutic function as a facilitator of the maintenance of these systems. However, predictions generated from this model have not yet been tested, and a lack of variables exists for deeper analyses of resilience. This study aims to address gaps in the Utilitarian Redundancy Model and to investigate the resilience of two medical systems in the Brazilian semi-arid zone. As a local illness is not always perceived in the same way that biomedicine recognizes, the term "therapeutic targets" is used for perceived illnesses. Semi-structured interviews with local experts were conducted using the free-listing technique to collect data on known medicinal plants, usage preferences, use of redundant species, characteristics of therapeutic targets, and the perceived severity for each target. Additionally, participatory workshops were conducted to determine the frequency of targets. The medical systems showed high species richness but low levels of species redundancy. However, if redundancy was present, it was the primary factor responsible for the maintenance of system functions. Species richness was positively associated with therapeutic target frequencies and negatively related to target severity. Moreover, information about redundant species seems to be largely idiosyncratic; this finding raises questions about the importance of redundancy for resilience. We stress the Utilitarian Redundancy Model as an interesting tool to be used in studies of resilience, but we emphasize that it must consider the distribution of redundancy in terms of the treatment of important illnesses and the sharing of information. This study has identified aspects of the higher and lower vulnerabilities of medical systems, adding

  12. Energy and speleogenesis: Key determinants of terrestrial species richness in caves.

    Science.gov (United States)

    Jiménez-Valverde, Alberto; Sendra, Alberto; Garay, Policarp; Reboleira, Ana Sofia P S

    2017-12-01

    The aim of this study was to unravel the relative role played by speleogenesis (i.e., the process in which a cave is formed), landscape-scale variables, and geophysical factors in the determination of species richness in caves. Biological inventories from 21 caves located in the southeastern Iberian Peninsula along with partial least square (PLS) regression analysis were used to assess the relative importance of the different explanatory variables. The caves were grouped according to the similarity in their species composition; the effect that spatial distance could have on similarity was also studied using correlation between matrices. The energy and speleogenesis of caves accounted for 44.3% of the variation in species richness. The trophic level of each cave was the most significant factor in PLS regression analysis, and epigenic caves (i.e., those formed by the action of percolating water) had significantly more species than hypogenic ones (i.e., those formed by the action of upward flows in confined aquifers). Dissimilarity among the caves was very high (multiple-site β sim  = 0.92). Two main groups of caves were revealed through the cluster analysis, one formed by the western caves and the other by the eastern ones. The significant-but low-correlation found between faunistic dissimilarity and geographical distance ( r  =   .16) disappeared once the caves were split into the two groups. The extreme beta-diversity suggests a very low connection among the caves and/or a very low dispersal capacity of the species. In the region under study, two main factors are intimately related to the richness of terrestrial subterranean species in caves: the amount of organic material (trophic level) and the formation process (genesis). This is the first time that the history of a cave genesis has been quantitatively considered to assess its importance in explaining richness patterns in comparison with other factors more widely recognized.

  13. Social organization influences the exchange and species richness of medicinal plants in Amazonian homegardens.

    Science.gov (United States)

    2016-03-01

    Medicinal plants provide indigenous and peasant communities worldwide with means to meet their healthcare needs. Homegardens often act as medicine cabinets, providing easily accessible medicinal plants for household needs. Social structure and social exchanges have been proposed as factors influencing the species diversity that people maintain in their homegardens. Here, we assess the association between the exchange of medicinal knowledge and plant material and medicinal plant richness in homegardens. Using Tsimane' Amazonian homegardens as a case study, we explore whether social organization shapes exchanges of medicinal plant knowledge and medicinal plant material. We also use network centrality measures to evaluate people's location and performance in medicinal plant knowledge and plant material exchange networks. Our results suggest that social organization, specifically kinship and gender relations, influences medicinal plant exchange patterns significantly. Homegardens total and medicinal plant species richness are related to gardeners' centrality in the networks, whereby people with greater centrality maintain greater plant richness. Thus, together with agroecological conditions, social relations among gardeners and the culturally specific social structure seem to be important determinants of plant richness in homegardens. Understanding which factors pattern general species diversity in tropical homegardens, and medicinal plant diversity in particular, can help policy makers, health providers, and local communities to understand better how to promote and preserve medicinal plants in situ. Biocultural approaches that are also gender sensitive offer a culturally appropriate means to reduce the global and local loss of both biological and cultural diversity.

  14. Relief influence on tree species richness in secondary forest fragments of Atlantic Forest, SE, Brazil

    OpenAIRE

    Silva,William Goulart da; Metzger,Jean Paul; Bernacci,Luis Carlos; Catharino,Eduardo Luís Martins; Durigan,Giselda; Simões,Sílvio

    2008-01-01

    The aim of this work was to explore the relationship between tree species richness and morphological characteristics of relief at the Ibiúna Plateau (SE Brazil). We sampled 61 plots of 0.30 ha, systematically established in 20 fragments of secondary forest (2-274 ha) and in three areas within a continuous secondary forest site, Morro Grande Reserve (9,400 ha). At each plot, 100 trees with diameter at breast height > 5 cm were sampled by the point centered quarter method, and total richness an...

  15. [Species-area and species-abundance relationships of arthropod community in various vegetation restoration areas in Zhifanggou watershed, Shaanxi province of Northwest China].

    Science.gov (United States)

    Zhang, Feng; Hong, Bo; Li, Ying-Mei; Chen, Zhi-Jie; Zhang, Shu-Lian; Zhao, Hui-Yan

    2013-02-01

    Taking the Zhifanggou watershed in Ansai, Shaanxi Province of Northwest China as a study unit, an investigation on the arthropods in 8 forest stands was conducted from 2006 to 2008, with the species-area and species-abundance relationships of the arthropods in these stands analyzed by various mathematical models. In these forest stands, the species-area relationship of the arthropods accorded with the formula S= CAm With the increase of investigation area, the species number approached to a constant, and the corresponding smallest investigation area was in the order of natural bush > natural forest > Populus davidiana+Robinia pseudoacacia forest > Hippaphae rhamnoides +Caragana mocrophylla forest> Periploca sepium forest > Hippaphae rhamnoides forest > Robinia pseudoacacia forest > Caragana mocrophylla forest, indicating that the more complex the stands, the larger the minimum area needed to be investigated. Based on sampling investigation, the species-abundance models of the arthropods in various stands were established. Lognormal distribution model (LN) was most suitable to fit the arthropod community in natural recovery stands, suggesting that in the arthropod community, there were more species with medial individual amount and fewer abundant species and rare species, and no obvious dominant species. LogCauchy distribution model (LC) was most suitable to fit the arthropod community in mixed and pure stands. As compared with natural recovery stand, mixed and pure stands had more abundant and rare species, and more dominant species.

  16. Aerial Survey as a Tool to Estimate Abundance and Describe Distribution of a Carcharhinid Species, the Lemon Shark, Negaprion brevirostris

    Directory of Open Access Journals (Sweden)

    S. T. Kessel

    2013-01-01

    Full Text Available Aerial survey provides an important tool to assess the abundance of both terrestrial and marine vertebrates. To date, limited work has tested the effectiveness of this technique to estimate the abundance of smaller shark species. In Bimini, Bahamas, the lemon shark (Negaprion brevirostris shows high site fidelity to a shallow sandy lagoon, providing an ideal test species to determine the effectiveness of localised aerial survey techniques for a Carcharhinid species in shallow subtropical waters. Between September 2007 and September 2008, visual surveys were conducted from light aircraft following defined transects ranging in length between 8.8 and 4.4 km. Count results were corrected for “availability”, “perception”, and “survey intensity” to provide unbiased abundance estimates. The abundance of lemon sharks was greatest in the central area of the lagoon during high tide, with a change in abundance distribution to the east and western regions of the lagoon with low tide. Mean abundance of sharks was estimated at 49 (±8.6 individuals, and monthly abundance was significantly positively correlated with mean water temperature. The successful implementation of the aerial survey technique highlighted the potential of further employment for shark abundance assessments in shallow coastal marine environments.

  17. Study of Plant Species Richness in Habitats with Different Grazing Intensities at Golestan National Park and Surrounding Area

    Directory of Open Access Journals (Sweden)

    A. Bagheri

    2016-12-01

    Full Text Available Considering the importance of plant diversity and to evaluate the effect of grazing pressure on species richness and structure of plant communities, this experiment was conducted at Golestan National Park and its surrounding areas in the north east of Iran. Sampling was conducted in intact and abandoned habitats and habitats under seasonal and heavy grazing, using Modified Whitaker Plot in 1, 10,100 and 1000 m2 spatial scales. Results showed that the composition of plant species from different habitats was different. In addition the increasing intensity of grazing increased the importance of therophytes and decreased the role of hemicryptophytes and phanerophytes and also decreasd the amount of species richness. Mean species richness of studied habitat showed a significant difference in all four sampling spatial scales. The results showed that plant species richness decreased in the areas affected by heavy grazing and conservation against grazing plays an important role in maintaining species richness.

  18. Allometric Equations for Estimating Biomass of Euterpe precatoria, the Most Abundant Palm Species in the Amazon

    Directory of Open Access Journals (Sweden)

    Fernando Da Silva

    2015-02-01

    Full Text Available Allometric models to estimate biomass components such as stem mass Ms, foliage mass Ml, root mass Mr and aboveground mass Ma, were developed for the palm species Euterpe precatoria Mart., which is the most abundant tree species in the Amazon. We harvested twenty palms including above- and below-ground parts in an old growth Amazonian forest in Brazil. The diameter at breast height D ranged from 3.9–12.7 cm, and the stem height H ranged from 2.3–16.4 m. The D, diameter at ground basis D0, crown diameter CD, H, stem specific gravity ρ, and number of fronds Nf were considered as independent variables and incorporated into a power function model. The best predictors were D2Hρ for Ms and Ma, D2HNf for Ml, and D for Mr. Slender index (H/D ranged from 0.56–1.46 m·cm−1, and the D-H relationship suggested that the stem shape becomes more slender with increasing D. On the other hand, ρ increased with D implying a stiffening of stem tissue. The average root/shoot ratio was estimated as 0.29 which was higher than that reported for the non-palm tree species in the Amazon. Comparisons of several models to estimate Ma of different palm species, suggested that the variations of the D-H relationship and ρ should be considered to develop allometric models for estimating biomass in palm species. In particular the ρ largely varied depending on individual size, which should be important to consider, when developing the allometric models for palms.

  19. Continuous gene flow contributes to low global species abundance and distribution of a marine model diatom

    KAUST Repository

    Rastogi, Achal

    2017-08-15

    Unlike terrestrial ecosystems where geographical isolation often leads to a restricted gene flow between species, genetic admixing in aquatic micro-eukaryotes is likely to be frequent. Diatoms inhabit marine ecosystems since the Mesozoic period and presently constitute one of the major primary producers in the world ocean. They are a highly diversified group of eukaryotic phytoplankton with estimates of up to 200,000 species. Since decades, Phaeodactylum tricornutum is used as a model diatom species to characterize the functional pathways, physiology and evolution of diatoms in general. In the current study, using whole genome sequencing of ten P. tricornutum strains, sampled at broad geospatial and temporal scales, we show a continuous dispersal and genetic admixing between geographically isolated strains. We also describe a very high level of heterozygosity and propose it to be a consequence of frequent ancestral admixture. Our finding that P. tricornutum sequences are plausibly detectable at low but broadly distributed levels in the world ocean further suggests that high admixing between geographically isolated strains may create a significant bottleneck, thus influencing their global abundance and distribution in nature. Finally, in an attempt to understand the functional implications of genetic diversity between different P. tricornutum ecotypes, we show the effects of domestication in inducing changes in the selection pressure on many genes and metabolic pathways. We propose these findings to have significant implications for understanding the genetic structure of diatom populations in nature and provide a framework to assess the genomic underpinnings of their ecological success.

  20. Continuous gene flow contributes to low global species abundance and distribution of a marine model diatom

    KAUST Repository

    Rastogi, Achal; Deton-Cabanillas, Anne-Flore; Rocha Jimenez Vieira, Fabio; Veluchamy, Alaguraj; Cantrel, Catherine; Wang, Gaohong; Vanormelingen, Pieter; Bowler, Chris; Piganeau, Gwenael; Tirichine, Leila; Hu, Hanhua

    2017-01-01

    Unlike terrestrial ecosystems where geographical isolation often leads to a restricted gene flow between species, genetic admixing in aquatic micro-eukaryotes is likely to be frequent. Diatoms inhabit marine ecosystems since the Mesozoic period and presently constitute one of the major primary producers in the world ocean. They are a highly diversified group of eukaryotic phytoplankton with estimates of up to 200,000 species. Since decades, Phaeodactylum tricornutum is used as a model diatom species to characterize the functional pathways, physiology and evolution of diatoms in general. In the current study, using whole genome sequencing of ten P. tricornutum strains, sampled at broad geospatial and temporal scales, we show a continuous dispersal and genetic admixing between geographically isolated strains. We also describe a very high level of heterozygosity and propose it to be a consequence of frequent ancestral admixture. Our finding that P. tricornutum sequences are plausibly detectable at low but broadly distributed levels in the world ocean further suggests that high admixing between geographically isolated strains may create a significant bottleneck, thus influencing their global abundance and distribution in nature. Finally, in an attempt to understand the functional implications of genetic diversity between different P. tricornutum ecotypes, we show the effects of domestication in inducing changes in the selection pressure on many genes and metabolic pathways. We propose these findings to have significant implications for understanding the genetic structure of diatom populations in nature and provide a framework to assess the genomic underpinnings of their ecological success.

  1. Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels.

    Science.gov (United States)

    Van der Putten, Wim H; Macel, Mirka; Visser, Marcel E

    2010-07-12

    Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on biotic interactions and use it to argue that the abundance of species and the direction of selection during climate change vary depending on how their trophic interactions become disrupted. Plant abundance can be controlled by aboveground and belowground multitrophic level interactions with herbivores, pathogens, symbionts and their enemies. We discuss how these interactions may alter during climate change and the resulting species range shifts. We suggest conceptual analogies between species responses to climate warming and exotic species introduced in new ranges. There are also important differences: the herbivores, pathogens and mutualistic symbionts of range-expanding species and their enemies may co-migrate, and the continuous gene flow under climate warming can make adaptation in the expansion zone of range expanders different from that of cross-continental exotic species. We conclude that under climate change, results of altered species interactions may vary, ranging from species becoming rare to disproportionately abundant. Taking these possibilities into account will provide a new perspective on predicting species distribution under climate change.

  2. Meta-analysis of carrying capacity and abundance-area relationships in marine fish species

    DEFF Research Database (Denmark)

    Mantzouni, Irene

    Knowledge on the carrying capacity and the abundance-area relationships of fish is critical to evaluate the impacts of exploitation and climate on the sustainability and also the recovery potential of the populations. Of particular interest is climate change, inducing major consequences for popul......Knowledge on the carrying capacity and the abundance-area relationships of fish is critical to evaluate the impacts of exploitation and climate on the sustainability and also the recovery potential of the populations. Of particular interest is climate change, inducing major consequences...... differences in the patterns were identified between stocks located in the upper and lower thermal range. In the latter, strong year-classes occurred mainly during warmer seasons and vice versa. For stocks located in the warmer waters, however, no significant patterns were obtained, suggesting that increased......, to incorporate the influence of ecosystem factors, mainly temperature and habitat size, on model parameters representing cod maximum reproductive rate and carrying capacity. The pattern of temperature effects on cod productivity at the species level were identified and SR model parameters were estimated...

  3. Testing Dragonflies as Species Richness Indicators in a Fragmented Subtropical Atlantic Forest Environment.

    Science.gov (United States)

    Renner, S; Sahlén, G; Périco, E

    2016-06-01

    We surveyed 15 bodies of water among remnants of the Atlantic Forest biome in southern Brazil for adult dragonflies and damselflies to test whether an empirical selection method for diversity indicators could be applied in a subtropical ecosystem, where limited ecological knowledge on species level is available. We found a regional species pool of 34 species distributed in a nested subset pattern with a mean of 11.2 species per locality. There was a pronounced difference in species composition between spring, summer, and autumn, but no differences in species numbers between seasons. Two species, Homeoura chelifera (Selys) and Ischnura capreolus (Hagen), were the strongest candidates for regional diversity indicators, being found only at species-rich localities in our surveyed area and likewise in an undisturbed national forest reserve, serving as a reference site for the Atlantic Forest. Using our selection method, we found it possible to obtain a tentative list of diversity indicators without having detailed ecological information of each species, providing a reference site is available for comparison. The method thus allows for indicator species to be selected in blanco from taxonomic groups that are little known. We hence argue that Odonata can already be incorporated in ongoing assessment programs in the Neotropics, which would also increase the ecological knowledge of the group and allow extrapolation to other taxa.

  4. Biomass production in experimental grasslands of different species richness during three years of climate warming

    Science.gov (United States)

    de Boeck, H. J.; Lemmens, C. M. H. M.; Zavalloni, C.; Gielen, B.; Malchair, S.; Carnol, M.; Merckx, R.; van den Berge, J.; Ceulemans, R.; Nijs, I.

    2008-04-01

    Here we report on the single and combined impacts of climate warming and species richness on the biomass production in experimental grassland communities. Projections of a future warmer climate have stimulated studies on the response of terrestrial ecosystems to this global change. Experiments have likewise addressed the importance of species numbers for ecosystem functioning. There is, however, little knowledge on the interplay between warming and species richness. During three years, we grew experimental plant communities containing one, three or nine grassland species in 12 sunlit, climate-controlled chambers in Wilrijk, Belgium. Half of these chambers were exposed to ambient air temperatures (unheated), while the other half were warmed by 3°C (heated). Equal amounts of water were added to heated and unheated communities, so that warming would imply drier soils if evapotranspiration was higher. Biomass production was decreased due to warming, both aboveground (-29%) and belowground (-25%), as negative impacts of increased heat and drought stress in summer prevailed. Complementarity effects, likely mostly through both increased aboveground spatial complementarity and facilitative effects of legumes, led to higher shoot and root biomass in multi-species communities, regardless of the induced warming. Surprisingly, warming suppressed productivity the most in 9-species communities, which may be attributed to negative impacts of intense interspecific competition for resources under conditions of high abiotic stress. Our results suggest that warming and the associated soil drying could reduce primary production in many temperate grasslands, and that this will not necessarily be mitigated by efforts to maintain or increase species richness.

  5. Meta-analysis of carrying capacity and abundance-area relationships in marine fish species

    DEFF Research Database (Denmark)

    Mantzouni, Irene

    investigated also across the north Atlantic distribution of haddock. The major motivations were first, to provide an evaluation of potential thermal effects on haddock recruitment productivity across its distribution, since the species is relatively less investigated on this regard compared to cod. In addition......Knowledge on the carrying capacity and the abundance-area relationships of fish is critical to evaluate the impacts of exploitation and climate on the sustainability and also the recovery potential of the populations. Of particular interest is climate change, inducing major consequences...... morhua), herring (Clupea harengus) and haddock (Melanogrammus aeglefinus), in order to identify the effects of temperature, habitat size and life-history on their productivity patterns. The first objective was to investigate how production and survival indices of cod recruitment (i.e. the number of new...

  6. Ferromanganese nodule fauna in the Tropical North Pacific Ocean: Species richness, faunal cover and spatial distribution

    Science.gov (United States)

    Veillette, Julie; Sarrazin, Jozée; Gooday, Andrew J.; Galéron, Joëlle; Caprais, Jean-Claude; Vangriesheim, Annick; Étoubleau, Joël; Christian, James R.; Kim Juniper, S.

    2007-11-01

    The poorly known ferromanganese nodule fauna is a widespread hard substratum community in the deep sea that will be considerably impacted by large-scale nodule mining operations. The objective of this study was to analyze the spatial distribution of the fauna attached to nodules in the Clarion-Clipperton Fracture Zone at two scales; a regional scale that includes the east (14°N, 130°W) and the west (9°N, 150°W) zones and a local scale in which different geological facies (A, B, C and west) are recognizable. The fauna associated with 235 nodules was quantitatively described: 104 nodules from the east zone (15 of facies A, 50 of facies B and 39 of facies C) and 131 nodules from the west zone. Percent cover was used to quantify the extent of colonization at the time of sampling, for 42 species out of the 62 live species observed. Fauna covered up to 18% of exposed nodule surface with an average of about 3%. While species richness increased with exposed nodule surface, both at the regional and at the facies scales (except for facies A), total species density decreased (again except for facies A). When all nodules were included in the statistical analysis, there was no relation between faunal cover and exposed nodule surface. Nevertheless, faunal cover did decrease with exposed nodule surface for the east zone in general and for both facies B and C in particular. Species distributions among facies were significantly different but explained only a very small portion of the variance (˜5%). We identified two groups of associated species: a first group of two species and a second group of six species. The other species (34) were independently distributed, suggesting that species interactions play only a minor role in the spatial distribution of nodule fauna. The flux of particulate organic carbon to the bottom is the only major environmental factor considered to vary between the two zones within this study. We conclude that the higher species richness and higher

  7. Incorporating biodiversity into rangeland health: Plant species richness and diversity in great plains grasslands

    Science.gov (United States)

    Symstad, Amy J.; Jonas, Jayne L.

    2011-01-01

    Indicators of rangeland health generally do not include a measure of biodiversity. Increasing attention to maintaining biodiversity in rangelands suggests that this omission should be reconsidered, and plant species richness and diversity are two metrics that may be useful and appropriate. Ideally, their response to a variety of anthropogenic and natural drivers in the ecosystem of interest would be clearly understood, thereby providing a means to diagnose the cause of decline in an ecosystem. Conceptual ecological models based on ecological principles and hypotheses provide a framework for this understanding, but these models must be supported by empirical evidence if they are to be used for decision making. To that end, we synthesize results from published studies regarding the responses of plant species richness and diversity to drivers that are of management concern in Great Plains grasslands, one of North America's most imperiled ecosystems. In the published literature, moderate grazing generally has a positive effect on these metrics in tallgrass prairie and a neutral to negative effect in shortgrass prairie. The largest published effects on richness and diversity were caused by moderate grazing in tallgrass prairies and nitrogen fertilization in shortgrass prairies. Although weather is often cited as the reason for considerable annual fluctuations in richness and diversity, little information about the responses of these metrics to weather is available. Responses of the two metrics often diverged, reflecting differences in their sensitivity to different types of changes in the plant community. Although sufficient information has not yet been published for these metrics to meet all the criteria of a good indicator in Great Plains Grasslands, augmenting current methods of evaluating rangeland health with a measure of plant species richness would reduce these shortcomings and provide information critical to managing for biodiversity.

  8. Scale-dependence of the correlation between human population and the species richness of stream macro-invertebrates

    DEFF Research Database (Denmark)

    Pecher, C.; Fritz, Susanne; Marini, L.

    2010-01-01

    . This is surprising as EPT are bio-indicators of stream pollution and most local studies report higher species richness of these macro-invertebrates where human influences on water quality are lower. Using a newly collated taxonomic dataset, we studied whether the species richness of EPT is related to human...

  9. Underestimation of species richness in neotropical frogs revealed by mtDNA analyses.

    Directory of Open Access Journals (Sweden)

    Antoine Fouquet

    2007-10-01

    Full Text Available Amphibians are rapidly vanishing. At the same time, it is most likely that the number of amphibian species is highly underestimated. Recent DNA barcoding work has attempted to define a threshold between intra- and inter-specific genetic distances to help identify candidate species. In groups with high extinction rates and poorly known species boundaries, like amphibians, such tools may provide a way to rapidly evaluate species richness.Here we analyse published and new 16S rDNA sequences from 60 frog species of Amazonia-Guianas to obtain a minimum estimate of the number of undescribed species in this region. We combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs.In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contrary to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species.Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia

  10. Arbovirus circulation, temporal distribution, and abundance of mosquito species in two Carolina bay habitats.

    Science.gov (United States)

    Ortiz, D I; Wozniak, A; Tolson, M W; Turner, P E

    2005-01-01

    Carolina bays, a type of geomorphic feature, may be important in the ecology of mosquito vectors in South Carolina. Their hydrology varies from wetland habitats with marked flooding/drying regimes to permanently flooded spring-fed lakes. Moreover, they possess characteristics that contribute to the support of a particularly abundant and diverse invertebrate fauna. Although it has been estimated that 2,700+ bays exist in South Carolina, approximately 97% have been altered; Heritage Preserve (SBHP) and Woods Bay State Park (WBSP), from June 1997 to July 1998 to determine mosquito temporal distribution, species composition, and the occurrence of arbovirus activity. The largest mosquito collection was obtained at WBSP (n = 31,172) representing 25 species followed by SBHP (n = 3,940) with 24 species. Anopheles crucians complex were the most common species encountered in both bays. Two virus isolates were obtained from SBHP in 1997: Keystone (KEY) virus from Ochlerotatus atlanticus-tormentor and Cache Valley (CV) virus from Oc. canadensis canadensis. Twenty-nine (29) arbovirus-positive pools were obtained from WBSP: 28 in 1997 and one in 1998. KEY virus was isolated from three pools of Oc. atlanticus-tormentor and Tensaw (TEN) virus was isolated from two pools of An. crucians complex; 10 isolates could not be identified with the sera available. Additionally, 14 pools of An. crucians complex tested positive for Eastern equine encephalitis (EEE) virus antigen. These represent the first record of KEY and CV viruses in South Carolina. Our data indicate the presence of high mosquito density and diversity in both Carolina bay habitats, which may be influenced, in part, by seasonal changes in their hydroperiods. The study of mosquito and arbovirus ecology in Carolina Bay habitats could provide more information on the transmission dynamics of arboviruses and its impact on human and animal arboviral disease occurrence in South Carolina.

  11. Species richness of squamate reptiles from two islands in the Mexican Pacific

    OpenAIRE

    Hernández-Salinas, Uriel; Ramírez-Bautista, Aurelio; Mata-Silva, Vicente

    2014-01-01

    Cocinas and San Pancho Islands, located in the Bay of Chamela, Jalisco, México, are two of the few remaining island ecosystems with little ecological disturbance. We studied both islands aiming to assess their reptile richness. Because the environment in Chamela is seasonal, we conducted biodiversity surveys during six samplings: three in the dry season and three in rainy season. We found a total of seven reptile species on Cocinas and San Pancho Islands representing the first description of ...

  12. Low species richness of non-biting midges (Diptera: Chironomidae) in Neotropical artificial urban water bodies

    DEFF Research Database (Denmark)

    Hamerlik, Ladislav; Jacobsen, Dean; Brodersen, Klaus Peter

    2011-01-01

    Chironomid assemblages of 22 artificial water bodies, mainly fountains, in two South American cities were surveyed. We found surprisingly low diversities, with a total of 11 taxa, averaging two taxa per site. The typical fountain assemblages mainly consisted of common species that have a wide...... distribution pattern and are tolerant to organic pollution. Also taxa independent of the natural aquatic sources, such as tap-water and semi-terrestrial species were represented. There was no significant difference between the taxa richness of the two S. American regions, however, the assemblage structures...

  13. Intransitive competition is widespread in plant communities and maintains their species richness.

    Science.gov (United States)

    Soliveres, Santiago; Maestre, Fernando T; Ulrich, Werner; Manning, Peter; Boch, Steffen; Bowker, Matthew A; Prati, Daniel; Delgado-Baquerizo, Manuel; Quero, José L; Schöning, Ingo; Gallardo, Antonio; Weisser, Wolfgang; Müller, Jörg; Socher, Stephanie A; García-Gómez, Miguel; Ochoa, Victoria; Schulze, Ernst-Detlef; Fischer, Markus; Allan, Eric

    2015-08-01

    Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity-richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in > 65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation. © 2015 John Wiley & Sons Ltd/CNRS.

  14. Species richness and distribution of bryophytes within different phytophysiognomies in the Chapada Diamantina region of Brazil

    Directory of Open Access Journals (Sweden)

    Emilia de Brito Valente

    2013-06-01

    Full Text Available The Chapada Diamantina ecoregion is within the caatinga (shrublands biome of Brazil. Environmental factors determine the phytophysiognomies that distinguish the ecoregion from the surrounding areas. This study aimed to investigate the distribution of bryophyte flora in this ecoregion, by phytophysiognomy and elevational zone. Analyzing specimens we collected from five municipalities in the region, together with specimens (previously collected from the region in herbaria, we identified 400 taxa. The phytophysiognomies that presented the highest species richness and the greatest numbers of exclusive taxa were forests and campos rupestres (dry, rocky grasslands, which respectively accounted for 51% and 40% of the taxa, compared with only 5% and 4%, respectively, for the caatinga and cerrado (savanna. Species richness and the numbers of exclusive taxa were highest in the lower and upper montane zones. There was a predominance of neotropical taxa and a significant number of disjunct species found in Brazil and in the Andes region. We conclude that the Chapada Diamantina region is an important center of bryophyte diversity, harboring not only a great number of species overall but also a considerable number of species exclusive to the region, primarily in forests and campos rupestres at elevations above 800 m.

  15. Wild felid species richness affected by a corridor in the Lacandona forest, Mexico

    Directory of Open Access Journals (Sweden)

    Gil–Fernández, M.

    2017-02-01

    Full Text Available Wild felids are one of the most vulnerable species due to habitat loss caused by fragmentation of ecosystems. We analyzed the effect of a structural corridor, defined as a strip of vegetation connecting two habitat patches, on the richness and habitat occupancy of felids on three sites in Marqués de Comillas, Chiapas, one with two isolated forest patches, the second with a structural corridor, and the third inside the Montes Azules Biosphere Reserve. We found only two species (L. pardalis and H. yagouaroundi in the isolated forest patches, five species in the structural corridor, and four species inside the Reserve. The corridor did not significantly affect occupancy, but due to the low detection rates, further investigation is needed to rule out differences. Our results highlight the need to manage habitat connectivity in the remaining forests in order to preserve the felid community of Marqués de Comillas, Chiapas, México.

  16. Rarity, species richness, and the threat of extinction--are plants the same as animals?

    Directory of Open Access Journals (Sweden)

    Sandra Knapp

    2011-05-01

    Full Text Available Assessment of conservation status is done both for areas or habitats and for species (or taxa. IUCN Red List categories have been the principal method of categorising species in terms of extinction risk, and have been shown to be robust and helpful in the groups for which they have been developed. A recent study highlights properties associated with extinction risk in flowering plants, focusing on the species-rich hot spot of the Cape region of South Africa, and concludes that merely following methods derived from studies of vertebrates may not provide the best estimates of extinction risk for plants. Biology, geography, and history all are important factors in risk, and the study poses many questions about how we categorise and assess species for conservation priorities.

  17. Fitting and comparing competing models of the species abundance distribution: assessment and prospect

    Directory of Open Access Journals (Sweden)

    Thomas J Matthews

    2014-06-01

    Full Text Available A species abundance distribution (SAD characterises patterns in the commonness and rarity of all species within an ecological community. As such, the SAD provides the theoretical foundation for a number of other biogeographical and macroecological patterns, such as the species–area relationship, as well as being an interesting pattern in its own right. While there has been resurgence in the study of SADs in the last decade, less focus has been placed on methodology in SAD research, and few attempts have been made to synthesise the vast array of methods which have been employed in SAD model evaluation. As such, our review has two aims. First, we provide a general overview of SADs, including descriptions of the commonly used distributions, plotting methods and issues with evaluating SAD models. Second, we review a number of recent advances in SAD model fitting and comparison. We conclude by providing a list of recommendations for fitting and evaluating SAD models. We argue that it is time for SAD studies to move away from many of the traditional methods available for fitting and evaluating models, such as sole reliance on the visual examination of plots, and embrace statistically rigorous techniques. In particular, we recommend the use of both goodness-of-fit tests and model-comparison analyses because each provides unique information which one can use to draw inferences.

  18. Historical abundance and morphology of Didymosphenia species in Naknek Lake, Alaska

    Science.gov (United States)

    Pite, D.P.; Lane, K.A.; Hermann, A.K.; Spaulding, S.A.; Finney, B.P.

    2009-01-01

    Since the 1980s, nuisance blooms of Didymosphenia geminata (Lyngbye) M. Schmidt have been documented in sites that are warmer and more mesotrophic than historical records indicate. While the invasion of D. geminata in New Zealand is well documented, it is less clear whether nuisance blooms in North America are a new phenomenon. In order to test the hypothesis that D. geminata blooms have increased in recent years, we examined the historical record of this species in sediments of Naknek Lake, in Katmai National Park, Alaska. Chronological control was established by relating the presence of two ash layers to known volcanic eruptions. We identified two species of Didymosphenia within the sediment record: D. geminata and D. clavaherculis (Ehrenberg) Metzeltin et Lange-Bertalot. This is the first published record of D. clavaherculis in North America. We found no statistically significant change in the numerical presence of D. geminata or D. clavaherculis, as a group, in Naknek Lake between the years 1218 and 2003. While there has been no sudden, or recent, increase in abundance of Didymosphenia in Naknek Lake, morphological features of D. geminata populations in Naknek Lake are distinct compared to morphological features of D. geminata in streams containing nuisance blooms from sites in North America and New Zealand. Variance in the morphology of Didymosphenia cells may help determine relationships between distinct sub-populations and establish the history of habitat invasion.

  19. Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae in coffee agroecosystems

    Directory of Open Access Journals (Sweden)

    Jeanneth Perez

    2014-02-01

    Full Text Available The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.], Finca Argovia (613 m a.s.l. and Teotihuacán del Valle (429 m a.s.l.. Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp.

  20. Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems

    Science.gov (United States)

    Pérez, Jeanneth; Virgen, Armando; Rojas, Julio Cesar; Rebollar-Téllez, Eduardo Alfonso; Alfredo, Castillo; Infante, Francisco; Mikery, Oscar; Marina, Carlos Felix; Ibáñez-Bernal, Sergio

    2013-01-01

    The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp. PMID:24271002

  1. Species richness of vascular plants along the climatic range of the Spanish dehesas at two spatial scales

    Directory of Open Access Journals (Sweden)

    Jose M. Garcia del Barrio

    2014-04-01

    Full Text Available Aims of study: The goals of this paper are to summarize and to compare plant species richness and floristic similarity at two spatial scales; mesohabitat (normal, eutrophic, and oligotrophic dehesas and dehesa habitat; and to establish guidelines for conserving species diversity in dehesas.Area of study: We considered four dehesa sites in the western Peninsular Spain, located along a climatic and biogeographic gradient from north to south. Main results: Average alpha richness for mesohabitats was 75.6 species, and average alpha richness for dehesa sites was 146.3. Gamma richness assessed for the overall dehesa habitat was 340.0 species. The species richness figures of normal dehesa mesohabitat were significantly lesser than of the eutrophic mesohabitat and lesser than the oligotrophic mesohabitat too. No significant differences were found for species richness among dehesa sites. We have found more dissimilarity at local scale (mesohabitat than at regional scale (habitat. Finally, the results of the similarity assessment between dehesa sites reflected both climatic and biogeographic gradients.Research highlights: An effective conservation of dehesas must take into account local and regional conditions all along their distribution range for ensuring the conservation of the main vascular plant species assemblages as well as the associated fauna.Keywords: Agroforestry systems; mesohabitat; non-parametric estimators; alpha richness; gamma richness; floristic similarity; climatic and biogeographic range.

  2. The origins of species richness in the Hymenoptera: insights from a family-level supertree

    Directory of Open Access Journals (Sweden)

    Davis Robert B

    2010-04-01

    Full Text Available Abstract Background The order Hymenoptera (bees, ants, wasps, sawflies contains about eight percent of all described species, but no analytical studies have addressed the origins of this richness at family-level or above. To investigate which major subtaxa experienced significant shifts in diversification, we assembled a family-level phylogeny of the Hymenoptera using supertree methods. We used sister-group species-richness comparisons to infer the phylogenetic position of shifts in diversification. Results The supertrees most supported by the underlying input trees are produced using matrix representation with compatibility (MRC (from an all-in and a compartmentalised analysis. Whilst relationships at the tips of the tree tend to be well supported, those along the backbone of the tree (e.g. between Parasitica superfamilies are generally not. Ten significant shifts in diversification (six positive and four negative are found common to both MRC supertrees. The Apocrita (wasps, ants, bees experienced a positive shift at their origin accounting for approximately 4,000 species. Within Apocrita other positive shifts include the Vespoidea (vespoid wasps/ants containing 24,000 spp., Anthophila + Sphecidae (bees/thread-waisted wasps; 22,000 spp., Bethylidae + Chrysididae (bethylid/cuckoo wasps; 5,200 spp., Dryinidae (dryinid wasps; 1,100 spp., and Proctotrupidae (proctotrupid wasps; 310 spp.. Four relatively species-poor families (Stenotritidae, Anaxyelidae, Blasticotomidae, Xyelidae have undergone negative shifts. There are some two-way shifts in diversification where sister taxa have undergone shifts in opposite directions. Conclusions Our results suggest that numerous phylogenetically distinctive radiations contribute to the richness of large clades. They also suggest that evolutionary events restricting the subsequent richness of large clades are common. Problematic phylogenetic issues in the Hymenoptera are identified, relating especially to

  3. Variation in leaf litter production and resorption of nutrients in abundant tree species in Nyungwe tropical montane rainforest in Rwanda

    Science.gov (United States)

    Nyirambangutse, Brigitte; Mirindi Dusenge, Eric; Nsabimana, Donat; Bizuru, Elias; Pleijel, Håkan; Uddling, Johan; Wallin, Göran

    2014-05-01

    African tropical rainforests play many roles from local to global scale as providers of resources and ecosystem services. Although covering 30% of the global rainforest, only few studies aiming to better understand the storage and fluxes of carbon and nutrients in these forests have been conducted. To answer questions related to these issues, we have established 15 permanent 0.5 ha plots where we compare carbon and nutrient fluxes of primary and secondary forest tree communities in a tropical montane forest in central Africa. The studies are conducted in Nyungwe montane tropical rain forest gazetted as a National Park to protect its extensive floral and faunal diversity covering an area of 970 km2. Nyungwe is located in Southwest Rwanda (2o17'-2o50'S, 29o07'-29o26A'E). The forest is ranging between 1600-2950 m.a.s.l. and is one of the most biologically important rainforest in Albertine Rift region in terms of Biodiversity. Nyungwe consists of a mixture of primary and secondary forest communities supporting a richness of plant and animal life. More than 260 species of trees and shrubs have been found in Nyungwe, including species endemic to the Albertine Rift. The forest has a climate with a mean annual temperature of 15.5oC and annual rainfall of ca 1850 mm yr-1, with July and August being the only months when rainfall drops. A part of this study is focusing on the dynamics of nutrients through leaf turnover. This turnover of leaves is regulated to maximize the carbon gain through canopy photosynthesis and resource-use efficiency of the plant. It is known that about half of leaf nitrogen is invested in photosynthetic apparatus and that there normally is a strong correlation between the photosynthetic capacity and leaf nitrogen per unit area. Hence leaf nitrogen is an important factor for canopy photosynthesis. However, leaves are produced, senesce and fall. Some nitrogen in the leaf is lost when leaves senesce but other is resorbed. The resorption of nitrogen

  4. Inferring species richness and turnover by statistical multiresolution texture analysis of satellite imagery.

    Directory of Open Access Journals (Sweden)

    Matteo Convertino

    Full Text Available BACKGROUND: The quantification of species-richness and species-turnover is essential to effective monitoring of ecosystems. Wetland ecosystems are particularly in need of such monitoring due to their sensitivity to rainfall, water management and other external factors that affect hydrology, soil, and species patterns. A key challenge for environmental scientists is determining the linkage between natural and human stressors, and the effect of that linkage at the species level in space and time. We propose pixel intensity based Shannon entropy for estimating species-richness, and introduce a method based on statistical wavelet multiresolution texture analysis to quantitatively assess interseasonal and interannual species turnover. METHODOLOGY/PRINCIPAL FINDINGS: We model satellite images of regions of interest as textures. We define a texture in an image as a spatial domain where the variations in pixel intensity across the image are both stochastic and multiscale. To compare two textures quantitatively, we first obtain a multiresolution wavelet decomposition of each. Either an appropriate probability density function (pdf model for the coefficients at each subband is selected, and its parameters estimated, or, a non-parametric approach using histograms is adopted. We choose the former, where the wavelet coefficients of the multiresolution decomposition at each subband are modeled as samples from the generalized Gaussian pdf. We then obtain the joint pdf for the coefficients for all subbands, assuming independence across subbands; an approximation that simplifies the computational burden significantly without sacrificing the ability to statistically distinguish textures. We measure the difference between two textures' representative pdf's via the Kullback-Leibler divergence (KL. Species turnover, or [Formula: see text] diversity, is estimated using both this KL divergence and the difference in Shannon entropy. Additionally, we predict species

  5. Evaluating Functional Diversity: Missing Trait Data and the Importance of Species Abundance Structure and Data Transformation

    Science.gov (United States)

    Bryndová, Michala; Kasari, Liis; Norberg, Anna; Weiss, Matthias; Bishop, Tom R.; Luke, Sarah H.; Sam, Katerina; Le Bagousse-Pinguet, Yoann; Lepš, Jan; Götzenberger, Lars; de Bello, Francesco

    2016-01-01

    Functional diversity (FD) is an important component of biodiversity that quantifies the difference in functional traits between organisms. However, FD studies are often limited by the availability of trait data and FD indices are sensitive to data gaps. The distribution of species abundance and trait data, and its transformation, may further affect the accuracy of indices when data is incomplete. Using an existing approach, we simulated the effects of missing trait data by gradually removing data from a plant, an ant and a bird community dataset (12, 59, and 8 plots containing 62, 297 and 238 species respectively). We ranked plots by FD values calculated from full datasets and then from our increasingly incomplete datasets and compared the ranking between the original and virtually reduced datasets to assess the accuracy of FD indices when used on datasets with increasingly missing data. Finally, we tested the accuracy of FD indices with and without data transformation, and the effect of missing trait data per plot or per the whole pool of species. FD indices became less accurate as the amount of missing data increased, with the loss of accuracy depending on the index. But, where transformation improved the normality of the trait data, FD values from incomplete datasets were more accurate than before transformation. The distribution of data and its transformation are therefore as important as data completeness and can even mitigate the effect of missing data. Since the effect of missing trait values pool-wise or plot-wise depends on the data distribution, the method should be decided case by case. Data distribution and data transformation should be given more careful consideration when designing, analysing and interpreting FD studies, especially where trait data are missing. To this end, we provide the R package “traitor” to facilitate assessments of missing trait data. PMID:26881747

  6. Species-abundance distribution patterns of soil fungi: contribution to the ecological understanding of their response to experimental fire in Mediterranean maquis (southern Italy).

    Science.gov (United States)

    Persiani, Anna Maria; Maggi, Oriana

    2013-01-01

    Experimental fires, of both low and high intensity, were lit during summer 2000 and the following 2 y in the Castel Volturno Nature Reserve, southern Italy. Soil samples were collected Jul 2000-Jul 2002 to analyze the soil fungal community dynamics. Species abundance distribution patterns (geometric, logarithmic, log normal, broken-stick) were compared. We plotted datasets with information both on species richness and abundance for total, xerotolerant and heat-stimulated soil microfungi. The xerotolerant fungi conformed to a broken-stick model for both the low- and high intensity fires at 7 and 84 d after the fire; their distribution subsequently followed logarithmic models in the 2 y following the fire. The distribution of the heat-stimulated fungi changed from broken-stick to logarithmic models and eventually to a log-normal model during the post-fire recovery. Xerotolerant and, to a far greater extent, heat-stimulated soil fungi acquire an important functional role following soil water stress and/or fire disturbance; these disturbances let them occupy unsaturated habitats and become increasingly abundant over time.

  7. Historical dynamics and current environmental effects explain the spatial distribution of species richness patterns of New World monkeys

    Directory of Open Access Journals (Sweden)

    Paulo Vallejos-Garrido

    2017-09-01

    Full Text Available Background Why biodiversity is not uniformly distributed on the Earth is a major research question of biogeography. One of the most striking patterns of disparity in species distribution are the biodiversity hotspots, which generally do not fit with the distribution of relevant components of the Neotropical biota. In this study, we assess the proximal causes of the species-richness pattern of one of the most conspicuous groups of Neotropical mammals, the New World monkeys the Platyrrhini. We test two complementary hypotheses: (1 there is a historical source-sink dynamic (addressed using macroevolutionary and macroecological approaches; (2 the large number of species in the Amazon basin is due to the constraints imposed by environmental variables occurring outside this area. Methods We first characterize spatial patterns of species richness and biodiversity hotspots using a new, objective protocol based on probabilities. Then we evaluate the source-sink hypothesis using BioGeoBEARS analysis and nestedness analysis of species richness patterns. Complementarily, to measure how often different species pairs appear in the same sites, we used null models to estimate the checkerboard score index (C-score. Finally, we evaluate the relationship between several climatic variables and species richness through ordinary least squares (OLS and spatial autoregressive (SAR models, and the potential environmental constraints on the pattern. Results We found one significant cluster of high values for species richness in the Amazon basin. Most dispersal events occurred from the Amazonian subregion to other Neotropical areas. Temperature (T, discrepancy (BR, and NODF indexes show a significant nesting in the matrix ordered by species richness and available energy. The C-score observed was significantly smaller than the null expectation for all sites in the Neotropics where there are records of platyrrhine species. Ten climatic variables comprised the best

  8. Topographic heterogeneity and temperature amplitude explain species richness patterns of birds in the Qinghai-Tibetan Plateau.

    Science.gov (United States)

    Zhang, Chunlan; Quan, Qing; Wu, Yongjie; Chen, Youhua; He, Peng; Qu, Yanhua; Lei, Fumin

    2017-04-01

    Large-scale patterns of species richness have gained much attention in recent years; however, the factors that drive high species richness are still controversial in local regions, especially in highly diversified montane regions. The Qinghai-Tibetan Plateau (QTP) and the surrounding mountains are biodiversity hot spots due to a high number of endemic montane species. Here, we explored the factors underlying this high level of diversity by studying the relationship between species richness and environmental variables. The richness patterns of 758 resident bird species were summarized at the scale of 1°×1° grid cell at different taxonomic levels (order, family, genus, and species) and in different taxonomic groups (Passeriformes, Galliformes, Falconiformes, and Columbiformes). These richness patterns were subsequently analyzed against habitat heterogeneity (topographical heterogeneity and land cover), temperature amplitude (annual temperature, annual precipitation, precipitation seasonality, and temperature seasonality) and a vegetation index (net primary productivity). Our results showed that the highest richness was found in the southeastern part of the QTP, the eastern Himalayas. The lowest richness was observed in the central plateau of the QTP. Topographical heterogeneity and temperature amplitude are the primary factors that explain overall patterns of species richness in the QTP, although the specific effect of each environmental variable varies between the different taxonomic groups depending on their own evolutionary histories and ecological requirements. High species richness in the southeastern QTP is mostly due to highly diversified habitat types and temperature zones along elevation gradients, whereas the low species richness in the central plateau of the QTP may be due to environmental and energetic constraints, as the central plateau is harsh environment.

  9. Tree Species Abundance Predictions in a Tropical Agricultural Landscape with a Supervised Classification Model and Imbalanced Data

    Directory of Open Access Journals (Sweden)

    Sarah J. Graves

    2016-02-01

    Full Text Available Mapping species through classification of imaging spectroscopy data is facilitating research to understand tree species distributions at increasingly greater spatial scales. Classification requires a dataset of field observations matched to the image, which will often reflect natural species distributions, resulting in an imbalanced dataset with many samples for common species and few samples for less common species. Despite the high prevalence of imbalanced datasets in multiclass species predictions, the effect on species prediction accuracy and landscape species abundance has not yet been quantified. First, we trained and assessed the accuracy of a support vector machine (SVM model with a highly imbalanced dataset of 20 tropical species and one mixed-species class of 24 species identified in a hyperspectral image mosaic (350–2500 nm of Panamanian farmland and secondary forest fragments. The model, with an overall accuracy of 62% ± 2.3% and F-score of 59% ± 2.7%, was applied to the full image mosaic (23,000 ha at a 2-m resolution to produce a species prediction map, which suggested that this tropical agricultural landscape is more diverse than what has been presented in field-based studies. Second, we quantified the effect of class imbalance on model accuracy. Model assessment showed a trend where species with more samples were consistently over predicted while species with fewer samples were under predicted. Standardizing sample size reduced model accuracy, but also reduced the level of species over- and under-prediction. This study advances operational species mapping of diverse tropical landscapes by detailing the effect of imbalanced data on classification accuracy and providing estimates of tree species abundance in an agricultural landscape. Species maps using data and methods presented here can be used in landscape analyses of species distributions to understand human or environmental effects, in addition to focusing conservation

  10. Hotspots of species richness, threat and endemism for terrestrial vertebrates in SW Europe

    Science.gov (United States)

    Pascual, López-López; Luigi, Maiorano; Alessandra, Falcucci; Emilio, Barba; Luigi, Boitani

    2011-09-01

    The Mediterranean basin, and the Iberian Peninsula in particular, represent an outstanding "hotspot" of biological diversity with a long history of integration between natural ecosystems and human activities. Using deductive distribution models, and considering both Spain and Portugal, we downscaled traditional range maps for terrestrial vertebrates (amphibians, breeding birds, mammals and reptiles) to the finest possible resolution with the data at hand, and we identified hotspots based on three criteria: i) species richness; ii) vulnerability, and iii) endemism. We also provided a first evaluation of the conservation status of biodiversity hotspots based on these three criteria considering both existing and proposed protected areas (i.e., Natura 2000). For the identification of hotspots, we used a method based on the cumulative distribution functions of species richness values. We found no clear surrogacy among the different types of hotspots in the Iberian Peninsula. The most important hotspots (considering all criteria) are located in the western and southwestern portions of the study area, in the Mediterranean biogeographical region. Existing protected areas are not specifically concentrated in areas of high species richness, with only 5.2% of the hotspots of total richness being currently protected. The Natura 2000 network can potentially constitute an important baseline for protecting vertebrate diversity in the Iberian Peninsula although further improvements are needed. We suggest taking a step forward in conservation planning in the Mediterranean basin, explicitly considering the history of the region as well as its present environmental context. This would allow moving from traditional reserve networks (conservation focused on "patterns") to considerations about the "processes" that generated present biodiversity.

  11. Abelhas Euglossini (Apidae de áreas de Mata Atlântica: abundância, riqueza e aspectos biológicos Euglossine bees (Apidae from Atlantic Forest sites: abundance, richness, and biological aspects

    Directory of Open Access Journals (Sweden)

    Rui Carlos Peruquetti

    1999-01-01

    Full Text Available Collection data of Euglossinae males from Parque Estadual do Rio Doce (PERD and Viçosa, both areas with remnants of Atlantic Rain Forest (Mata Atlântica in Minas Gerais state, Brazil are presented. Comparisons made among three fragments with different sizes and states of disturbance from Viçosa showed differences in abundance of most common species and apparently, Eulaema nigrita Lepeletir, 1841 can be an useful indicator of disturbed sites. Some populations of euglossine bees seems to be restrict to a forest fragment, there being few or no flow of individuals or species of one fragment to another, even when they are only 1 km apart. 15 species of euglossines were sampled in PERD, and the most abundant was Eulaema cingulata (Fabricius, 1804. At Viçosa, 10 species were sampled, E. nigrita was the predominant one. Methyl salicylate attracted no males at both sites, in spite of large numbers of species and individuals sampled using this bait in other regions. The majority of species and individuals were collected in the rainy season. Only 0,58% of sampled males carried orchid pollinia (Catasetum Richard, Cycnoches Lindley and Coryanthes Hook on their bodies. Emergence data of four species of Euglossa Latreille, 1802 reared from trap nests suggest that sex ratio in Euglossini is not a constant within the tribe. A list of 57 euglossine species now known to occur in Mata Atlântica are offered.

  12. Species composition, richness and nestedness of lizard assemblages from Restinga habitats along the brazilian coast

    Directory of Open Access Journals (Sweden)

    CFD. Rocha

    Full Text Available Habitat fragmentation is well known to adversely affect species living in the remaining, relatively isolated, habitat patches, especially for those having small range size and low density. This negative effect has been critical in coastal resting habitats. We analysed the lizard composition and richness of restinga habitats in 16 restinga habitats encompassing three Brazilian states (Rio de Janeiro, Espírito Santo and Bahia and more than 1500km of the Brazilian coast in order to evaluate if the loss of lizard species following habitat reduction occur in a nested pattern or at random, using the “Nestedness Temperature Calculator” to analyse the distribution pattern of lizard species among the restingas studied. We also estimated the potential capacity that each restinga has to maintain lizard species. Eleven lizard species were recorded in the restingas, although not all species occurred in all areas. The restinga with the richest lizard fauna was Guriri (eight species whereas the restinga with the lowest richness was Praia do Sul (located at Ilha Grande, a large coastal island. Among the restingas analysed, Jurubatiba, Guriri, Maricá and Praia das Neves, were the most hospitable for lizards. The matrix community temperature of the lizard assemblages was 20.49° (= P <0.00001; 5000 randomisations; randomisation temperature = 51.45° ± 7.18° SD, indicating that lizard assemblages in the coastal restingas exhibited a considerable nested structure. The degree in which an area is hospitable for different assemblages could be used to suggest those with greater value of conservation. We concluded that lizard assemblages in coastal restingas occur at a considerable level of ordination in restinga habitats and that some restinga areas such as Jurubatiba, Guriri, Maricá and Praia das Neves are quite important to preserve lizard diversity of restinga environments.

  13. Species composition, richness and nestedness of lizard assemblages from Restinga habitats along the brazilian coast.

    Science.gov (United States)

    Rocha, C F D; Vrcibradic, D; Kiefer, M C; Menezes, V A; Fontes, A F; Hatano, F H; Galdino, C A B; Bergallo, H G; Van Sluys, M

    2014-05-01

    Habitat fragmentation is well known to adversely affect species living in the remaining, relatively isolated, habitat patches, especially for those having small range size and low density. This negative effect has been critical in coastal resting habitats. We analysed the lizard composition and richness of restinga habitats in 16 restinga habitats encompassing three Brazilian states (Rio de Janeiro, Espírito Santo and Bahia) and more than 1500km of the Brazilian coast in order to evaluate if the loss of lizard species following habitat reduction occur in a nested pattern or at random, using the "Nestedness Temperature Calculator" to analyse the distribution pattern of lizard species among the restingas studied. We also estimated the potential capacity that each restinga has to maintain lizard species. Eleven lizard species were recorded in the restingas, although not all species occurred in all areas. The restinga with the richest lizard fauna was Guriri (eight species) whereas the restinga with the lowest richness was Praia do Sul (located at Ilha Grande, a large coastal island). Among the restingas analysed, Jurubatiba, Guriri, Maricá and Praia das Neves, were the most hospitable for lizards. The matrix community temperature of the lizard assemblages was 20.49° (= P restingas exhibited a considerable nested structure. The degree in which an area is hospitable for different assemblages could be used to suggest those with greater value of conservation. We concluded that lizard assemblages in coastal restingas occur at a considerable level of ordination in restinga habitats and that some restinga areas such as Jurubatiba, Guriri, Maricá and Praia das Neves are quite important to preserve lizard diversity of restinga environments.

  14. Functional-diversity indices can be driven by methodological choices and species richness.

    Science.gov (United States)

    Poos, Mark S; Walker, Steven C; Jackson, Donald A

    2009-02-01

    Functional diversity is an important concept in community ecology because it captures information on functional traits absent in measures of species diversity. One popular method of measuring functional diversity is the dendrogram-based method, FD. To calculate FD, a variety of methodological choices are required, and it has been debated about whether biological conclusions are sensitive to such choices. We studied the probability that conclusions regarding FD were sensitive, and that patterns in sensitivity were related to alpha and beta components of species richness. We developed a randomization procedure that iteratively calculated FD by assigning species into two assemblages and calculating the probability that the community with higher FD varied across methods. We found evidence of sensitivity in all five communities we examined, ranging from a probability of sensitivity of 0 (no sensitivity) to 0.976 (almost completely sensitive). Variations in these probabilities were driven by differences in alpha diversity between assemblages and not by beta diversity. Importantly, FD was most sensitive when it was most useful (i.e., when differences in alpha diversity were low). We demonstrate that trends in functional-diversity analyses can be largely driven by methodological choices or species richness, rather than functional trait information alone.

  15. The relationship between species richness and ecosystem variability is shaped by the mechanism of coexistence.

    Science.gov (United States)

    Tredennick, Andrew T; Adler, Peter B; Adler, Frederick R

    2017-08-01

    Theory relating species richness to ecosystem variability typically ignores the potential for environmental variability to promote species coexistence. Failure to account for fluctuation-dependent coexistence may explain deviations from the expected negative diversity-ecosystem variability relationship, and limits our ability to predict the consequences of increases in environmental variability. We use a consumer-resource model to explore how coexistence via the temporal storage effect and relative nonlinearity affects ecosystem variability. We show that a positive, rather than negative, diversity-ecosystem variability relationship is possible when ecosystem function is sampled across a natural gradient in environmental variability and diversity. We also show how fluctuation-dependent coexistence can buffer ecosystem functioning against increasing environmental variability by promoting species richness and portfolio effects. Our work provides a general explanation for variation in observed diversity-ecosystem variability relationships and highlights the importance of conserving regional species pools to help buffer ecosystems against predicted increases in environmental variability. © 2017 John Wiley & Sons Ltd/CNRS.

  16. Changes of Species Richness in Heathland Communities over 15 Years following Disturbances

    Directory of Open Access Journals (Sweden)

    L. Calvo

    2012-01-01

    Full Text Available The aim of this study was to define the species richness patterns over a period of 15 years during the vegetation recovery process after disturbances (burning, cutting and ploughing in heathlands. Three communities were selected: two dominated by Erica australis and one dominated by Calluna vulgaris. The alpha and gamma diversity patterns were site specific and influenced by the ecological traits of dominant shrub species. The shrubland dominated by Erica australis, typical resprouters with a fast regeneration, showed the highest values of alpha and gamma diversity during the first 7 years of regeneration. The heathland dominated by Calluna vulgaris, an obligate seeder, had a contrasting pattern of alpha and gamma diversity, as the highest values appeared from year 7 until year 14. Thus, the speed of regeneration of the dominant shrub species could be the main factor affecting structural parameters in these communities. Species richness patterns did not vary in relation to the different types of perturbation. Cutting and burning would be the most suitable forestry management strategies to conserve Erica australis heathlands, but burning is more appropriate in Calluna vulgaris ones because cutting modified this community.

  17. Evolutionary history determines how plant productivity responds to phylogenetic diversity and species richness

    Directory of Open Access Journals (Sweden)

    Mark A. Genung

    2014-03-01

    Full Text Available The relationship between biodiversity and ecosystem function has received a great deal of attention in ecological research and recent results, from re-analyses, suggest that ecosystem function improves with increases in phylogenetic diversity. However, many of these results have been generalized across a range of different species and clades, and plants with different evolutionary histories could display different relationships between biodiversity and ecosystem function. To experimentally test this hypothesis, we manipulated species richness and phylogenetic diversity using 26 species from two subgenera of the genus Eucalyptus (subgenus Eucalyptus and subgenus Symphyomyrtus. We found that plant biomass (a measurement of ecosystem function sometimes, but not always, responded to increases in species richness and phylogenetic diversity. Specifically, Symphyomyrtus plants showed a positive response while no comparable effect was observed for Eucalyptus plants, showing that responses to biodiversity can vary across different phylogenetic groups. Our results show that the impacts of evolutionary history may complicate the relationship between the diversity of plant communities and plant biomass.

  18. Shrubs as ecosystem engineers across an environmental gradient: effects on species richness and exotic plant invasion.

    Science.gov (United States)

    Kleinhesselink, Andrew R; Magnoli, Susan M; Cushman, J Hall

    2014-08-01

    Ecosystem-engineering plants modify the physical environment and can increase species diversity and exotic species invasion. At the individual level, the effects of ecosystem engineers on other plants often become more positive in stressful environments. In this study, we investigated whether the community-level effects of ecosystem engineers also become stronger in more stressful environments. Using comparative and experimental approaches, we assessed the ability of a native shrub (Ericameria ericoides) to act as an ecosystem engineer across a stress gradient in a coastal dune in northern California, USA. We found increased coarse organic matter and lower wind speeds within shrub patches. Growth of a dominant invasive grass (Bromus diandrus) was facilitated both by aboveground shrub biomass and by growing in soil taken from shrub patches. Experimental removal of shrubs negatively affected species most associated with shrubs and positively affected species most often found outside of shrubs. Counter to the stress-gradient hypothesis, the effects of shrubs on the physical environment and individual plant growth did not increase across the established stress gradient at this site. At the community level, shrub patches increased beta diversity, and contained greater rarified richness and exotic plant cover than shrub-free patches. Shrub effects on rarified richness increased with environmental stress, but effects on exotic cover and beta diversity did not. Our study provides evidence for the community-level effects of shrubs as ecosystem engineers in this system, but shows that these effects do not necessarily become stronger in more stressful environments.

  19. [Study on spatial distribution characteristics of traditional Chinese medicine resource species richness based on national census of Chinese medicine resources (pilot)].

    Science.gov (United States)

    Zhang, Xiao-Bo; Wang, Hui; Jing, Zhi-Xian; Li, Meng; Guo, Lan-Ping; Huang, Lu-Qi

    2017-11-01

    Based on the data collected by the census team in the national census information management system, the spatial autocorrelation analysis method was used to analyze the similarity of the richness of Chinese herbal medicine resources in the investigated counties. The results showed that the species richness in the investigated counties appeared a tendency to focus on the distribution of the characteristics. Among them, the areas with sparse resources are concentrated in most areas of the north of the Yangtze River, northwest and most areas of Tibet. The areas with abundant resources are concentrated in the areas south of the Yangtze River. The results showed that there were significant differences in the abundance of traditional Chinese medicine resources between regions. The results showed that there were significant differences in the abundance of traditional Chinese medicine resources between regions. Due to the large differences in the land area between the county and the richness of the types of traditional Chinese medicine resources, it is proposed to increase the land area of the traditional Chinese medicine resource census when allocating the fourth national census of Chinese medicine resources by the "factor method", and the richness of traditional Chinese medicine and other indicators, in order to give full play to the efficiency of transfer payment system. Based on the county area and the rich variety of traditional Chinese medicine resources, combined with the national drug resources census pilot work carried out, it is recommended to focus on attention and support in the national medicine resources census work, personnel team, funding, summary of results on the western and southern provinces. Copyright© by the Chinese Pharmaceutical Association.

  20. Ecological impacts of tropical forest fragmentation: how consistent are patterns in species richness and nestedness?

    Science.gov (United States)

    Hill, Jane K; Gray, Michael A; Khen, Chey Vun; Benedick, Suzan; Tawatao, Noel; Hamer, Keith C

    2011-11-27

    Large areas of tropical forest now exist as remnants scattered across agricultural landscapes, and so understanding the impacts of forest fragmentation is important for biodiversity conservation. We examined species richness and nestedness among tropical forest remnants in birds (meta-analysis of published studies) and insects (field data for fruit-feeding Lepidoptera (butterflies and moths) and ants). Species-area relationships were evident in all four taxa, and avian and insect assemblages in remnants typically were nested subsets of those in larger areas. Avian carnivores and nectarivores and predatory ants were more nested than other guilds, implying that the sequential loss of species was more predictable in these groups, and that fragmentation alters the trophic organization of communities. For butterflies, the ordering of fragments to achieve maximum nestedness was by fragment area, suggesting that differences among fragments were driven mainly by extinction. In contrast for moths, maximum nestedness was achieved by ordering species by wing length; species with longer wings (implying better dispersal) were more likely to occur at all sites, including low diversity sites, suggesting that differences among fragments were driven more strongly by colonization. Although all four taxa exhibited high levels of nestedness, patterns of species turnover were also idiosyncratic, and thus even species-poor sites contributed to landscape-scale biodiversity, particularly for insects.

  1. Differential responses of soil bacteria, fungi, archaea and protists to plant species richness and plant functional group identity.

    Science.gov (United States)

    Dassen, Sigrid; Cortois, Roeland; Martens, Henk; de Hollander, Mattias; Kowalchuk, George A; van der Putten, Wim H; De Deyn, Gerlinde B

    2017-08-01

    Plants are known to influence belowground microbial community structure along their roots, but the impacts of plant species richness and plant functional group (FG) identity on microbial communities in the bulk soil are still not well understood. Here, we used 454-pyrosequencing to analyse the soil microbial community composition in a long-term biodiversity experiment at Jena, Germany. We examined responses of bacteria, fungi, archaea, and protists to plant species richness (communities varying from 1 to 60 sown species) and plant FG identity (grasses, legumes, small herbs, tall herbs) in bulk soil. We hypothesized that plant species richness and FG identity would alter microbial community composition and have a positive impact on microbial species richness. Plant species richness had a marginal positive effect on the richness of fungi, but we observed no such effect on bacteria, archaea and protists. Plant species richness also did not have a large impact on microbial community composition. Rather, abiotic soil properties partially explained the community composition of bacteria, fungi, arbuscular mycorrhizal fungi (AMF), archaea and protists. Plant FG richness did not impact microbial community composition; however, plant FG identity was more effective. Bacterial richness was highest in legume plots and lowest in small herb plots, and AMF and archaeal community composition in legume plant communities was distinct from that in communities composed of other plant FGs. We conclude that soil microbial community composition in bulk soil is influenced more by changes in plant FG composition and abiotic soil properties, than by changes in plant species richness per se. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  2. Snow cover and extreme winter warming events control flower abundance of some, but not all species in high arctic Svalbard

    DEFF Research Database (Denmark)

    Semenchuk, Philipp R.; Elberling, Bo; Cooper, Elisabeth J.

    2013-01-01

    octopetala. However, the affected species were resilient and individuals did not experience any long term effects. In the case of short or cold summers, a subset of species suffered reduced reproductive success, which may affect future plant composition through possible cascading competition effects. Extreme...... winter warming events were shown to expose the canopy to cold winter air. The following summer most of the overwintering flower buds could not produce flowers. Thus reproductive success is reduced if this occurs in subsequent years. We conclude that snow depth influences flower abundance by altering...... events, while Stellaria crassipes responded partly. Snow pack thickness determined whether winter warming events had an effect on flower abundance of some species. Warming events clearly reduced flower abundance in shallow but not in deep snow regimes of Cassiope tetragona, but only marginally for Dryas...

  3. Semiparametric bivariate zero-inflated Poisson models with application to studies of abundance for multiple species

    Science.gov (United States)

    Arab, Ali; Holan, Scott H.; Wikle, Christopher K.; Wildhaber, Mark L.

    2012-01-01

    Ecological studies involving counts of abundance, presence–absence or occupancy rates often produce data having a substantial proportion of zeros. Furthermore, these types of processes are typically multivariate and only adequately described by complex nonlinear relationships involving externally measured covariates. Ignoring these aspects of the data and implementing standard approaches can lead to models that fail to provide adequate scientific understanding of the underlying ecological processes, possibly resulting in a loss of inferential power. One method of dealing with data having excess zeros is to consider the class of univariate zero-inflated generalized linear models. However, this class of models fails to address the multivariate and nonlinear aspects associated with the data usually encountered in practice. Therefore, we propose a semiparametric bivariate zero-inflated Poisson model that takes into account both of these data attributes. The general modeling framework is hierarchical Bayes and is suitable for a broad range of applications. We demonstrate the effectiveness of our model through a motivating example on modeling catch per unit area for multiple species using data from the Missouri River Benthic Fishes Study, implemented by the United States Geological Survey.

  4. A database of marine phytoplankton abundance, biomass and species composition in Australian waters

    Science.gov (United States)

    Davies, Claire H.; Coughlan, Alex; Hallegraeff, Gustaaf; Ajani, Penelope; Armbrecht, Linda; Atkins, Natalia; Bonham, Prudence; Brett, Steve; Brinkman, Richard; Burford, Michele; Clementson, Lesley; Coad, Peter; Coman, Frank; Davies, Diana; Dela-Cruz, Jocelyn; Devlin, Michelle; Edgar, Steven; Eriksen, Ruth; Furnas, Miles; Hassler, Christel; Hill, David; Holmes, Michael; Ingleton, Tim; Jameson, Ian; Leterme, Sophie C.; Lønborg, Christian; McLaughlin, James; McEnnulty, Felicity; McKinnon, A. David; Miller, Margaret; Murray, Shauna; Nayar, Sasi; Patten, Renee; Pritchard, Tim; Proctor, Roger; Purcell-Meyerink, Diane; Raes, Eric; Rissik, David; Ruszczyk, Jason; Slotwinski, Anita; Swadling, Kerrie M.; Tattersall, Katherine; Thompson, Peter; Thomson, Paul; Tonks, Mark; Trull, Thomas W.; Uribe-Palomino, Julian; Waite, Anya M.; Yauwenas, Rouna; Zammit, Anthony; Richardson, Anthony J.

    2016-06-01

    There have been many individual phytoplankton datasets collected across Australia since the mid 1900s, but most are unavailable to the research community. We have searched archives, contacted researchers, and scanned the primary and grey literature to collate 3,621,847 records of marine phytoplankton species from Australian waters from 1844 to the present. Many of these are small datasets collected for local questions, but combined they provide over 170 years of data on phytoplankton communities in Australian waters. Units and taxonomy have been standardised, obviously erroneous data removed, and all metadata included. We have lodged this dataset with the Australian Ocean Data Network (http://portal.aodn.org.au/) allowing public access. The Australian Phytoplankton Database will be invaluable for global change studies, as it allows analysis of ecological indicators of climate change and eutrophication (e.g., changes in distribution; diatom:dinoflagellate ratios). In addition, the standardised conversion of abundance records to biomass provides modellers with quantifiable data to initialise and validate ecosystem models of lower marine trophic levels.

  5. Frog species richness, composition and beta-diversity in coastal Brazilian restinga habitats.

    Science.gov (United States)

    Rocha, C F D; Hatano, F H; Vrcibradic, D; Van Sluys, M

    2008-02-01

    We studied the species richness and composition of frogs in 10 restinga habitats (sand dune environments dominated by herbaceous and shrubby vegetation) along approximately 1500 km of coastal areas of three Brazilian States: Rio de Janeiro (Grumari, Maricá, Massambaba, Jurubatiba and Grussaí), Espírito Santo (Praia das Neves and Setiba) and Bahia (Prado and Trancoso). We estimated beta-diversity and similarity among areas and related these parameters to geographic distance between areas. All areas were surveyed with a similar sampling procedure. We found 28 frog species belonging to the families Hylidae, Microhylidae, Leptodactylidae and Bufonidae. Frogs in restingas were in general nocturnal with no strictly diurnal species. The richest restinga was Praia das Neves (13 species), followed by Grussaí and Trancoso (eight species in each). The commonest species in the restingas was Scinax alter (found in eight restingas), followed by Aparasphenodon brunoi (seven areas). Our data shows that richness and composition of frog communities vary consistently along the eastern Brazilian coast and, in part, the rate of species turnover is affected by the distance among areas. Geographic distance explained approximately 12% of species turnover in restingas and about 9.5% of similarity among frog assemblages. Although geographic distance somewhat affects frog assemblages, other factors (e.g. historical factors, disturbances) seem to be also involved in explaining present frog assemblage composition in each area and species turnover among areas. The frog fauna along restinga habitats was significantly nested (matrix community temperature = 26.13 degrees; p = 0.007). Our data also showed that the most hospitable restinga was Praia das Neves and indicated that this area should be protected as a conservation unit. Frog assemblage of each area seems to partially represent a nested subset of the original assemblage, although we should not ignore the importance of historical

  6. Frog species rich