WorldWideScience

Sample records for invasive grass litter

  1. Leaf litter variation influences invasion dynamics in the invasive wetland grass Phalaris arundinacea

    NARCIS (Netherlands)

    Kaproth, M.A.; Eppinga, M.B.; Molofsky, J.

    High litter mass is hypothesized to produce an invader-directed invasion by changing ecosystem properties such as nutrient cycling rates and light availability. An invasive plant species that stimulates litter accumulation may induce a positive feedback when it benefits from high litter

  2. The role of plant litter on nutrient mineralization and vegetation dynamics in three sage-steppe communities with differing levels of annual grass invasion

    Science.gov (United States)

    Plant litter is an integral part of ecosystem nutrient cycling, which directly impacts vegetation dynamics. The net effects of litter are largely determined by the quantity and source material of the litter. Invasion of sage-steppe communities by annual grasses (e.g., Bromus tectorum) has caused dra...

  3. Decoupling litter barrier and soil moisture influences on the establishment of an invasive grass

    Science.gov (United States)

    Robert J. Warren; Volker Bahn; Mark A.. Bradford

    2013-01-01

    Through recruitment, plants establish in novel environments. Recruitment also is the stage where plants undergo the highest mortality. We investigate the recruitment niche for Microstegium vimineum, an annual grass from East Asia spreading throughout eastern North American forests. Current observational and greenhouse research indicates that M. vimineum recruitment may...

  4. Plant litter effects on soil nutrient availability and vegetation dynamics: changes that occur when annual grasses invade shrub-steppe communities

    Science.gov (United States)

    Sheel Bansal; Roger L. Sheley; Bob Blank; Edward A. Vasquez

    2014-01-01

    Changes in the quantity and quality of plant litter occur in many ecosystems as they are invaded by exotic species, which impact soil nutrient cycling and plant community composition. Such changes in sagebrush-steppe communities are occurring with invasion of annual grasses (AG) into a perennial grass (PG) dominated system. We conducted a 5-year litter manipulation...

  5. Invasive grasses change landscape structure and fire behavior in Hawaii

    Science.gov (United States)

    Lisa M. Ellsworth; Creighton M. Litton; Alexander P. Dale; Tomoaki Miura

    2014-01-01

    How does potential fire behavior differ in grass-invaded non-native forests vs open grasslands? How has land cover changed from 1950–2011 along two grassland/forest ecotones in Hawaii with repeated fires? A study on non-native forest with invasive grass understory and invasive grassland (Megathyrsus maximus) ecosystems on Oahu, Hawaii, USA was...

  6. Effect of ponderosa pine needle litter on grass seedling survival.

    Science.gov (United States)

    Burt R. McConnell; Justin G. Smith

    1971-01-01

    Hard fescue survival rates were followed for 6 years on four different pine needle treatment plots. Needle litter had a significant effect on initial survival of fescue seedlings, but subsequent losses undoubtedly resulted from the interaction of many factors.

  7. Toxicity of iron oxide nanoparticles to grass litter decomposition in a sandy soil

    Science.gov (United States)

    Rashid, Muhammad Imtiaz; Shahzad, Tanvir; Shahid, Muhammad; Imran, Muhammad; Dhavamani, Jeyakumar; Ismail, Iqbal M. I.; Basahi, Jalal M.; Almeelbi, Talal

    2017-02-01

    We examined time-dependent effect of iron oxide nanoparticles (IONPs) at a rate of 2000 mg kg-1 soil on Cynodon dactylon litter (3 g kg-1) decomposition in an arid sandy soil. Overall, heterotrophic cultivable bacterial and fungal colonies, and microbial biomass carbon were significantly decreased in litter-amended soil by the application of nanoparticles after 90 and 180 days of incubation. Time dependent effect of nanoparticles was significant for microbial biomass in litter-amended soil where nanoparticles decreased this variable from 27% after 90 days to 49% after 180 days. IONPs decreased CO2 emission by 28 and 30% from litter-amended soil after 90 and 180 days, respectively. These observations indicated that time-dependent effect was not significant on grass-litter carbon mineralization efficiency. Alternatively, nanoparticles application significantly reduced mineral nitrogen content in litter-amended soil in both time intervals. Therefore, nitrogen mineralization efficiency was decreased to 60% after 180 days compared to that after 90 days in nanoparticles grass-litter amended soil. These effects can be explained by the presence of labile Fe in microbial biomass after 180 days in nanoparticles amendment. Hence, our results suggest that toxicity of IONPs to soil functioning should consider before recommending their use in agro-ecosystems.

  8. Litter drives ecosystem and plant community changes in cattail invasion.

    Science.gov (United States)

    Farrer, Emily C; Goldberg, Deborah E

    2009-03-01

    Invaded systems are commonly associated with a change in ecosystem processes and a decline in native species diversity; however, many different causal pathways linking invasion, ecosystem change, and native species decline could produce this pattern. The initial driver of environmental change may be anthropogenic, or it may be the invader itself; and the mechanism behind native species decline may be the human-induced environmental change, competition from the invader, or invader-induced environmental change (non-trophic effects). We examined applicability of each of these alternate pathways in Great Lakes coastal marshes invaded by hybrid cattail (Typha x glauca). In a survey including transects in three marshes, we found that T. x glauca was associated with locally high soil nutrients, low light, and large amounts of litter, and that native diversity was highest in areas of shallow litter depth. We tested whether live T. x glauca plants or their litter induced changes in the environment and in diversity with a live plant and litter transplant experiment. After one year, Typha litter increased soil NH4+ and N mineralization twofold, lowered light levels, and decreased the abundance and diversity of native plants, while live Typha plants had no effect on the environment or on native plants. This suggests that T. x glauca, through its litter production, can cause the changes in ecosystem processes that we commonly attribute to anthropogenic nutrient loading and that T. x glauca does not displace native species through competition for resources, but rather affects them non-trophically through its litter. Moreover, because T. x glauca plants were taller when grown with their own litter, we suggest that this invader may produce positive feedbacks and change the environment in ways that benefit itself and may promote its own invasion.

  9. Habitat structure modified by an invasive grass enhances inundation withstanding in a salt-marsh wolf spider

    OpenAIRE

    Pétillon, J.; Lambeets, K.; Montaigne, W.; Maelfait, J.-P.; Bonte, D.

    2010-01-01

    Vegetation and underground structures are known to influence flood avoidance and flood resistance in invertebrates. In bimonthly-flooded European salt marshes, recent invasions by the nitrophilous grass Elymus athericus strongly modified usual habitat structure, notably by the production of a deep litter layer. Consequently, invaded habitats provide more interstitial spaces that may act as a refuge during flood events. By using both controlled and field designs, we tested whether invaded habi...

  10. Effect of petroleum on decomposition of shrub-grass litters in soil in Northern Shaanxi of China.

    Science.gov (United States)

    Zhang, Xiaoxi; Liu, Zengwen; Yu, Qi; Luc, Nhu Trung; Bing, Yuanhao; Zhu, Bochao; Wang, Wenxuan

    2015-07-01

    The impacts of petroleum contamination on the litter decomposition of shrub-grass land would directly influence nutrient cycling, and the stability and function of ecosystem. Ten common shrub and grass species from Yujiaping oil deposits were studied. Litters from these species were placed into litterbags and buried in petroleum-contaminated soil with 3 levels of contamination (slight, moderate and serious pollution with petroleum concentrations of 15, 30 and 45 g/kg, respectively). A decomposition experiment was then conducted in the lab to investigate the impacts of petroleum contamination on litter decomposition rates. Slight pollution did not inhibit the decomposition of any litters and significantly promoted the litter decomposition of Hippophae rhamnoides, Caragana korshinskii, Amorpha fruticosa, Ziziphus jujuba var. spinosa, Periploca sepium, Medicago sativa and Bothriochloa ischaemum. Moderate pollution significantly inhibited litter decomposition of M. sativa, Coronilla varia, Artemisia vestita and Trrifolium repens and significantly promoted the litter decomposition of C. korshinskii, Z. jujuba var. spinosa and P. sepium. Serious pollution significantly inhibited the litter decomposition of H. rhamnoides, A. fruticosa, B. ischaemum and A. vestita and significantly promoted the litter decomposition of Z. jujuba var. spinosa, P. sepium and M. sativa. In addition, the impacts of petroleum contamination did not exhibit a uniform increase or decrease as petroleum concentration increased. Inhibitory effects of petroleum on litter decomposition may hinder the substance cycling and result in the degradation of plant communities in contaminated areas. Copyright © 2015. Published by Elsevier B.V.

  11. Invasive warm-season grasses reduce mycorrhizal root colonization and biomass production of native prairie grasses.

    Science.gov (United States)

    Wilson, Gail W T; Hickman, Karen R; Williamson, Melinda M

    2012-07-01

    Soil organisms play important roles in regulating ecosystem-level processes and the association of arbuscular mycorrhizal (AM) fungi with a plant species can be a central force shaping plant species' ecology. Understanding how mycorrhizal associations are affected by plant invasions may be a critical aspect of the conservation and restoration of native ecosystems. We examined the competitive ability of old world bluestem, a non-native grass (Caucasian bluestem [Bothriochloa bladhii]), and the influence of B. bladhii competition on AM root colonization of native warm-season prairie grasses (Andropogon gerardii or Schizachyrium scoparium), using a substitutive design greenhouse competition experiment. Competition by the non-native resulted in significantly reduced biomass production and AM colonization of the native grasses. To assess plant-soil feedbacks of B. bladhii and Bothriochloa ischaemum, we conducted a second greenhouse study which examined soil alterations indirectly by assessing biomass production and AM colonization of native warm-season grasses planted into soil collected beneath Bothriochloa spp. This study was conducted using soil from four replicate prairie sites throughout Kansas and Oklahoma, USA. Our results indicate that a major mechanism in plant growth suppression following invasion by Bothriochloa spp. is the alteration in soil microbial communities. Plant growth was tightly correlated with AM root colonization demonstrating that mycorrhizae play an important role in the invasion of these systems by Bothriochloa spp. and indicating that the restoration of native AM fungal communities may be a fundamental consideration for the successful establishment of native grasses into invaded sites.

  12. Established native perennial grasses out-compete an invasive annual grass regardless of soil water and nutrient availability

    Science.gov (United States)

    Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb; Ty Nietupsky

    2012-01-01

    Competition and resource availability influence invasions into native perennial grasslands by nonnative annual grasses such as Bromus tectorum. In two greenhouse experiments we examined the influence of competition, water availability, and elevated nitrogen (N) and phosphorus (P) availability on growth and reproduction of the invasive annual grass B. tectorum and two...

  13. Genotypic diversity of an invasive plant species promotes litter decomposition and associated processes.

    Science.gov (United States)

    Wang, Xiao-Yan; Miao, Yuan; Yu, Shuo; Chen, Xiao-Yong; Schmid, Bernhard

    2014-03-01

    Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter.

  14. Climate change and the invasion of California by grasses

    DEFF Research Database (Denmark)

    Sandel, Brody Steven; Dangremond, Emily

    2012-01-01

    Over the next century, changes in the global climate are expected to have major consequences for plant communities, possibly including the exacerbation of species invasions. We evaluated this possibility in the grass flora of California, which is economically and ecologically important and heavily...... richness relative to native richness in California; warmer areas contain higher proportions of exotic species. This pattern was very well captured by a simple model that predicts invasion severity given only the trait–climate relationship for native species and trait differences between native and exotic...... species. This study provides some of the first evidence for an important interaction between climate change and species invasions across very broad geographic and taxonomic scales....

  15. Pyricularia pennisetigena and P. zingibericola from invasive grasses infect signal grass, barley and wheat

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    Juliana Teodora de Assis Reges

    2016-06-01

    Full Text Available Fungal species from the Pyricularia genus are associated with blast disease in plants from the Poaceae family, causing losses in economically important crops such as rice, oat, rye, barley, wheat and triticale. This study aimed at characterizing the pathogenicity spectrum of P. pennisetigena and P. zingibericola to signal grass, barley and wheat, as well as comparing them with those from the species P. grisea and P. oryzae pathotype Triticum, which occur widely in the Brazilian agroecosystem. Twenty isolates of Pyricularia spp. were obtained from infected leaf samples of invasive plant species from wheat fields. The isolates classification into distinct Pyricularia species was done using molecular phylogeny based on actin and calmodulin genes. Pyricularia pennisetigena and P. zingibericola inoculated on plant leaves, at a concentration adjusted to 105 conidia mL-1, were pathogenic to signal grass, barley and wheat, with varying levels of aggressiveness.

  16. Grasses as invasive plants in South Africa revisited: Patterns, pathways and management

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    Vernon Visser

    2017-03-01

    Full Text Available Background: In many countries around the world, the most damaging invasive plant species are grasses. However, the status of grass invasions in South Africa has not been documented recently. Objectives: To update Sue Milton’s 2004 review of grasses as invasive alien plants in South Africa, provide the first detailed species level inventory of alien grasses in South Africa and assess the invasion dynamics and management of the group. Method: We compiled the most comprehensive inventory of alien grasses in South Africa to date using recorded occurrences of alien grasses in the country from various literature and database sources. Using historical literature, we reviewed past efforts to introduce alien grasses into South Africa. We sourced information on the origins, uses, distributions and minimum residence times to investigate pathways and patterns of spatial extent. We identified alien grasses in South Africa that are having environmental and economic impacts and determined whether management options have been identified, and legislation created, for these species. Results: There are at least 256 alien grass species in the country, 37 of which have become invasive. Alien grass species richness increased most dramatically from the late 1800s to about 1940. Alien grass species that are not naturalised or invasive have much shorter residence times than those that have naturalised or become invasive. Most grasses were probably introduced for forage purposes, and a large number of alien grass species were trialled at pasture research stations. A large number of alien grass species in South Africa are of Eurasian origin, although more recent introductions include species from elsewhere in Africa and from Australasia. Alien grasses are most prevalent in the south-west of the country, and the Fynbos Biome has the most alien grasses and the most widespread species. We identified 11 species that have recorded environmental and economic impacts in the

  17. How does altered precipitation and annual grass invasion affect plant N uptake in a native semi-arid shrub community?

    Science.gov (United States)

    Mauritz, M.; Lipson, D.; Cleland, E. E.

    2012-12-01

    Climate change is expected to alter precipitation patterns, which will change the timing and amount of plant resources. Precipitation patterns determine water and nitrogen (N) availability, because water stimulates microbial N turnover and N transport. In order for plants to utilize water and N, they must coincide with the phenology and meet physiological requirements of the plant. As resource supply shifts, differences in species' ability to acquire resources will affect plant community composition. Semiarid ecosystems, such as shrublands in Southern California, are particularly sensitive to shifts in precipitation because they are severely water limited. This study takes advantage of the altered phenology and resource demands presented by invasive annual grasses in a native semiarid shrubland. The goal is to understand how altered precipitation patterns affect plant N uptake. Rainfall levels were manipulated to 50% and 150% of ambient levels. It is expected that higher rainfall levels promote annual grass invasion because grasses have higher water and N requirements and begin to grow earlier in the season than shrubs. A 15N tracer was added with the first rain event and plant samples were collected regularly to track the movement of N into the plants. Net soil N accumulation was determined using resin bags. Invasive grasses altered the timing and amount of N uptake but amount of rainfall had less effect on N distribution. 15N was detected sooner and at higher level in grasses than shrubs. 24hours after the first rain event 15N was detectable in grasses, 15N accumulated rapidly and peaked 2 months earlier than shrubs. Shrub 15N levels remained at pre-rain event levels for the first 2 months and began to increase at the beginning of spring, peak mid-spring and decline as the shrubs entered summer dormancy. One year later 15N levels in annual grass litter remained high, while 15N levels in shrubs returned to initial background levels as a result of resorption. 15N

  18. Soil modification by invasive plants: Effects on native and invasive species of mixed-grass prairies

    Science.gov (United States)

    Jordan, N.R.; Larson, D.L.; Huerd, S.C.

    2008-01-01

    Invasive plants are capable of modifying attributes of soil to facilitate further invasion by conspecifics and other invasive species. We assessed this capability in three important plant invaders of grasslands in the Great Plains region of North America: leafy spurge (Euphorbia esula), smooth brome (Bromus inermis) and crested wheatgrass (Agropyron cristatum). In a glasshouse, these three invasives or a group of native species were grown separately through three cycles of growth and soil conditioning in both steam-pasteurized and non-pasteurized soils, after which we assessed seedling growth in these soils. Two of the three invasive species, Bromus and Agropyron, exhibited significant self-facilitation via soil modification. Bromus and Agropyron also had significant facilitative effects on other invasives via soil modification, while Euphorbia had significant antagonistic effects on the other invasives. Both Agropyron and Euphorbia consistently suppressed growth of two of three native forbs, while three native grasses were generally less affected. Almost all intra- and interspecific effects of invasive soil conditioning were dependent upon presence of soil biota from field sites where these species were successful invaders. Overall, these results suggest that that invasive modification of soil microbiota can facilitate plant invasion directly or via 'cross-facilitation' of other invasive species, and moreover has potential to impede restoration of native communities after removal of an invasive species. However, certain native species that are relatively insensitive to altered soil biota (as we observed in the case of the forb Linum lewisii and the native grasses), may be valuable as 'nurse'species in restoration efforts. ?? 2007 Springer Science+Business Media B.V.

  19. Selective logging and fire as drivers of alien grass invasion in a Bolivian tropical dry forest

    NARCIS (Netherlands)

    Veldman, J.W.; Mostacedo, B.; Peña-Claros, M.; Putz, F.E.

    2009-01-01

    Logging is an integral component of most conceptual models that relate human land-use and climate change to tropical deforestation via positive-feedbacks involving fire. Given that grass invasions can substantially alter fire regimes, we studied grass distributions in a tropical dry forest 1-5 yr

  20. Pathways of invasive plant spread to Alaska: III. contaminants in crop and grass seed

    Science.gov (United States)

    Invasive plants disperse to new areas via numerous pathways. Study of these pathways helps to focus limited budgets for prevention and early detection. This study examined seed contaminants in imported crop and grass seed as pathway for plant dispersal to Alaska. Crop and grass seed were purchased f...

  1. Soil sterilization alters interactions between the native grass Bouteloua gracilis and invasive Bromus tectorum

    Science.gov (United States)

    Aims: The invasive grass Bromus tectorum negatively impacts grassland communities throughout the western U.S. We asked whether soil biota growing in association with a native grass (Bouteloua gracilis) increase growth and competitive ability of Bromus, and whether responses vary between soils collec...

  2. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna

    Science.gov (United States)

    Borrell Pichs, Yaisel J.; García-Vazquez, Eva

    2018-01-01

    Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse

  3. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

    Directory of Open Access Journals (Sweden)

    Sabine Rech

    Full Text Available Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas and the Australian barnacle (Austrominius modestus. The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a

  4. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

    Science.gov (United States)

    Rech, Sabine; Borrell Pichs, Yaisel J; García-Vazquez, Eva

    2018-01-01

    Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse

  5. Reductions in native grass biomass associated with drought facilitates the invasion of an exotic grass into a model grassland system.

    Science.gov (United States)

    Manea, Anthony; Sloane, Daniel R; Leishman, Michelle R

    2016-05-01

    The invasion success of exotic plant species is often dependent on resource availability. Aspects of climate change such as rising atmospheric CO2 concentration and extreme climatic events will directly and indirectly alter resource availability in ecological communities. Understanding how these climate change-associated changes in resource availability will interact with one another to influence the invasion success of exotic plant species is complex. The aim of the study was to assess the establishment success of an invasive exotic species in response to climate change-associated changes in resource availability (CO2 levels and soil water availability) as a result of extreme drought. We grew grassland mesocosms consisting of four co-occurring native grass species common to the Cumberland Plain Woodland of western Sydney, Australia, under ambient and elevated CO2 levels and subjected them to an extreme drought treatment. We then added seeds of a highly invasive C3 grass, Ehrharta erecta, and assessed its establishment success (biomass production and reproductive output). We found that reduced biomass production of the native grasses in response to the extreme drought treatment enhanced the establishment success of E. erecta by creating resource pulses in light and space. Surprisingly, CO2 level did not affect the establishment success of E. erecta. Our results suggest that the invasion risk of grasslands in the future may be coupled to soil water availability and the subsequent response of resident native vegetation therefore making it strongly context- dependent.

  6. Faster N Release, but Not C Loss, From Leaf Litter of Invasives Compared to Native Species in Mediterranean Ecosystems

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    Guido Incerti

    2018-04-01

    Full Text Available Plant invasions can have relevant impacts on biogeochemical cycles, whose extent, in Mediterranean ecosystems, have not yet been systematically assessed comparing litter carbon (C and nitrogen (N dynamics between invasive plants and native communities. We carried out a 1-year litterbag experiment in 4 different plant communities (grassland, sand dune, riparian and mixed forests on 8 invasives and 24 autochthonous plant species, used as control. Plant litter was characterized for mass loss, N release, proximate lignin and litter chemistry by 13C CPMAS NMR. Native and invasive species showed significant differences in litter chemical traits, with invaders generally showing higher N concentration and lower lignin/N ratio. Mass loss data revealed no consistent differences between native and invasive species, although some woody and vine invaders showed exceptionally high decomposition rate. In contrast, N release rate from litter was faster for invasive plants compared to native species. N concentration, lignin content and relative abundance of methoxyl and N-alkyl C region from 13C CPMAS NMR spectra were the parameters that better explained mass loss and N mineralization rates. Our findings demonstrate that during litter decomposition invasive species litter has no different decomposition rates but greater N release rate compared to natives. Accordingly, invasives are expected to affect N cycle in Mediterranean plant communities, possibly promoting a shift of plant assemblages.

  7. Diet Switching by Mammalian Herbivores in Response to Exotic Grass Invasion.

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    Carolina Bremm

    Full Text Available Invasion by exotic grasses is a severe threat to the integrity of grassland ecosystems all over the world. Because grasslands are typically grazed by livestock and wildlife, the invasion is a community process modulated by herbivory. We hypothesized that the invasion of native South American grasslands by Eragrostis plana Nees, an exotic tussock-forming grass from Africa, could be deterred by grazing if grazers switched dietary preferences and included the invasive grass as a large proportion of their diets. Bos taurus (heifers and Ovis aries (ewes grazed plots with varying degrees of invasion by E. plana in a replicated manipulative experiment. Animal positions and species grazed were observed every minute in 45-min grazing session. Proportion of bites and steps in and out of E. plana tussocks were measured and used to calculate several indices of selectivity. Both heifers and ewes exhibited increasing probability of grazing E. plana as the proportion of area covered by tussocks increased, but they behaved differently. In agreement with expectations based on the allometry of dietary preferences and morphology, ewes consumed a low proportion of E. plana, except in areas that had more than 90% E. plana cover. Heifers consumed proportionally more E. plana than ewes. Contrary to our hypothesis, herbivores did not exhibit dietary switching towards the invasive grass. Moreover, they exhibited avoidance of the invasive grass and preference for short-statured native species, both of which should tend to enhance invasion. Unless invasive plants are highly palatable to livestock, the effect of grazing to deter the invasion is limited, due to the inherent avoidance of the invasive grass by the main grazers in the ecosystem, particularly sheep.

  8. Litter Fall and Its Decomposition in Sapium sebiferum Roxb.: An Invasive Tree Species in Western Himalaya

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    Vikrant Jaryan

    2014-01-01

    Full Text Available Recognizing that high litter fall and its rapid decomposition are key traits of invasive species, litter fall and its decay in Sapium sebiferum Roxb. were studied in Palampur. For this, litter traps of dimension 50 × 50 × 50 cm3 were placed in under-canopy and canopy gap of the species. Litter fall was monitored monthly and segregated into different components. For litter decay studies, litter bags of dimension 25 × 20 cm2 with a mesh size 2 mm were used and the same were analyzed on a fortnightly basis. Litter fall in both under-canopy and canopy gap was highest in November (1.16 Mg ha−1 y−1 in under-canopy and 0.38 Mg ha−1 y−1 in canopy gap and lowest during March. Litter production in under-canopy and canopy gap was 4.04 Mg ha−1 y−1 and 1.87 Mg ha−1 y−1, respectively. These values are comparable to sal forest (1.7 t C ha−1 y−1, chir pine-mixed forest (2.1 t C ha−1 y−1, and mixed oak-conifer forest (2.8 t C ha−1 y−1 of the Western Himalaya. The decay rate, 0.46% day−1 in under-canopy and 0.48% day−1 in canopy gap, was also fast. Owing to this the species may be able to modify the habitats to its advantage, as has been reported elsewhere.

  9. Hyperspectral remote sensing tools for quantifying plant litter and invasive species in arid ecosystems

    Science.gov (United States)

    Nagler, Pamela L.; Sridhar, B.B. Maruthi; Olsson, Aaryn Dyami; Glenn, Edward P.; van Leeuwen, Willem J.D.; Thenkabail, Prasad S.; Huete, Alfredo; Lyon, John G.

    2012-01-01

    Green vegetation can be distinguished using visible and infrared multi-band and hyperspectral remote sensing methods. The problem has been in identifying and distinguishing the non-photosynthetically active radiation (PAR) landscape components, such as litter and soils, and from green vegetation. Additionally, distinguishing different species of green vegetation is challenging using the relatively few bands available on most satellite sensors. This chapter focuses on hyperspectral remote sensing characteristics that aim to distinguish between green vegetation, soil, and litter (or senescent vegetation). Quantifying litter by remote sensing methods is important in constructing carbon budgets of natural and agricultural ecosystems. Distinguishing between plant types is important in tracking the spread of invasive species. Green leaves of different species usually have similar spectra, making it difficult to distinguish between species. However, in this chapter we show that phenological differences between species can be used to detect some invasive species by their distinct patterns of greening and dormancy over an annual cycle based on hyperspectral data. Both applications require methods to quantify the non-green cellulosic fractions of plant tissues by remote sensing even in the presence of soil and green plant cover. We explore these methods and offer three case studies. The first concerns distinguishing surface litter from soil using the Cellulose Absorption Index (CAI), as applied to no-till farming practices where plant litter is left on the soil after harvest. The second involves using different band combinations to distinguish invasive saltcedar from agricultural and native riparian plants on the Lower Colorado River. The third illustrates the use of the CAI and NDVI in time-series analyses to distinguish between invasive buffelgrass and native plants in a desert environment in Arizona. Together the results show how hyperspectral imagery can be applied to

  10. Decomposition of Phragmites australis litter retarded by invasive Solidago canadensis in mixtures: an antagonistic non-additive effect

    Science.gov (United States)

    Zhang, Ling; Zhang, Yaojun; Zou, Jianwen; Siemann, Evan

    2014-06-01

    Solidago canadensis is an aggressive invader in China. Solidago invasion success is partially attributed to allelopathic compounds release and more benefits from AM fungi, which potentially makes the properties of Solidago litter different from co-occurring natives. These properties may comprehensively affect litter decomposition of co-occurring natives. We conducted a field experiment to examine litter mixing effects in a Phragmites australis dominated community invaded by Solidago in southeast China. Solidago had more rapid mass and N loss rate than Phragmites when they decomposed separately. Litter mixing decreased N loss rate in Phragmites litter and increased that of Solidago. Large decreases in Phragmites mass loss and smaller increases in Solidago mass loss caused negative non-additive effect. Solidago litter extracts reduced soil C decomposition and N processes, suggested an inhibitory effect of Solidago secondary compounds. These results are consistent with the idea that nutrient transfer and secondary compounds both affected litter mixtures decomposition.

  11. Decomposition of Phragmites australis litter retarded by invasive Solidago canadensis in mixtures: an antagonistic non-additive effect

    OpenAIRE

    Zhang, Ling; Zhang, Yaojun; Zou, Jianwen; Siemann, Evan

    2014-01-01

    Solidago canadensis is an aggressive invader in China. Solidago invasion success is partially attributed to allelopathic compounds release and more benefits from AM fungi, which potentially makes the properties of Solidago litter different from co-occurring natives. These properties may comprehensively affect litter decomposition of co-occurring natives. We conducted a field experiment to examine litter mixing effects in a Phragmites australis dominated community invaded by Solidago in southe...

  12. Ecology, genetics, and biological control of invasive annual grasses in the Great Basin

    Science.gov (United States)

    Several annual grass species native to Eurasia, including cheatgrass (Bromus tectorum), red brome (B. rubens), and medusahead (Taeniatherum caput-medusae) have become invasive in the western USA. These invasive species degrade rangelands by compromising forage, outcompeting native flora, and exacerb...

  13. Non-native plant litter enhances soil carbon dioxide emissions in an invaded annual grassland.

    Science.gov (United States)

    Zhang, Ling; Wang, Hong; Zou, Jianwen; Rogers, William E; Siemann, Evan

    2014-01-01

    Litter decomposition is a fundamental ecosystem process in which breakdown and decay of plant detritus releases carbon and nutrients. Invasive exotic plants may produce litter that differs from native plant litter in quality and quantity. Such differences may impact litter decomposition and soil respiration in ways that depend on whether exotic and native plant litters decompose in mixtures. However, few field experiments have examined how exotic plants affect soil respiration via litter decomposition. Here, we conducted an in situ study of litter decomposition of an annual native grass (Eragrostis pilosa), a perennial exotic forb (Alternanthera philoxeroides), and their mixtures in an annual grassland in China to examine potential invasion effects on soil respiration. Alternanthera litter decomposed faster than Eragrostis litter when each was incubated separately. Mass loss in litter mixes was more rapid than predicted from rates in single species bags (only 35% of predicted mass remained at 8 months) showing synergistic effects. Notably, exotic plant litter decomposition rate was unchanged but native plant litter decomposition rate was accelerated in mixtures (decay constant k = 0.20 month(-1)) compared to in isolation (k = 0.10 month(-1)). On average, every litter type increased soil respiration compared to bare soil from which litter was removed. However, the increases were larger for mixed litter (1.82 times) than for Alternanthera litter (1.58 times) or Eragrostis litter (1.30 times). Carbon released as CO2 relative to litter carbon input was also higher for mixed litter (3.34) than for Alternathera litter (2.29) or Eragrostis litter (1.19). Our results indicated that exotic Alternanthera produces rapidly decomposing litter which also accelerates the decomposition of native plant litter in litter mixtures and enhances soil respiration rates. Thus, this exotic invasive plant species will likely accelerate carbon cycling and increase soil respiration

  14. Direct and indirect effects of an invasive omnivore crayfish on leaf litter decomposition.

    Science.gov (United States)

    Carvalho, Francisco; Pascoal, Cláudia; Cássio, Fernanda; Sousa, Ronaldo

    2016-01-15

    Invasive alien species (IAS) can disrupt important ecological functions in aquatic ecosystems; however, many of these effects are not quantified and remain speculative. In this study, we assessed the effects of the invasive crayfish Procambarus clarkii (Girard, 1852) on leaf litter decomposition (a key ecosystem process) and associated invertebrates using laboratory and field manipulative experiments. The crayfish had significant impacts on leaf decomposition due to direct consumption of leaf litter and production of fine particulate organic matter, and indirectly due to consumption of invertebrate shredders. The invertebrate community did not appear to recognize P. clarkii as a predator, at least in the first stages after its introduction in the system; but this situation might change with time. Overall, results suggested that the omnivore invader P. clarkii has the potential to affect detritus-based food webs through consumption of basal resources (leaf litter) and/or consumers. Recognizing that this IAS is widespread in Europe, Asia and Africa, and may attain high density and biomass in aquatic ecosystems, our results are important to develop strategies for improving stream ecosystem functioning and to support management actions aiming to control the invasive omnivore P. clarkii. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Alternative pathways to landscape transformation: Invasive grasses, burn severity and fire frequency in arid ecosystems

    Science.gov (United States)

    Klinger, Robert C.; Brooks, Matthew L.

    2017-01-01

    Arid ecosystems are often vulnerable to transformation to invasive-dominated states following fire, but data on persistence of these states are sparse. The grass/fire cycle is a feedback process between invasive annual grasses and fire frequency that often leads to the formation of alternative vegetation states dominated by the invasive grasses. However, other components of fire regimes, such as burn severity, also have the potential to produce long-term vegetation transformations. Our goal was to evaluate the influence of both fire frequency and burn severity on the transformation of woody-dominated communities to communities dominated by invasive grasses in major elevation zones of the Mojave Desert of western North America.We used a chronosequence design to collect data on herbaceous and woody cover at 229 unburned reference plots and 578 plots that burned between 1972 and 2010. We stratified the plots by elevation zone (low, mid, high), fire frequency (1–3 times) and years post-fire (YPF; 1–5, 6–10, 11–20 and 21–40 YPF). Burn severity for each plot was estimated by the difference normalized burn ratio.We identified two broad post-fire successional pathways. One was an outcome of fire frequency, resulting in a strong potential transformation via the grass/fire cycle. The second pathway was driven by burn severity, the critical aspect being that long-term transformation of a community could occur from just one fire in areas that burned at high or sometimes moderate severity. Dominance by invasive grasses was most likely to occur in low-and high-elevation communities; cover of native herbaceous species was often greater than that of invasive grasses in the mid-elevation zone.Synthesis. Invasive grasses can dominate a site that burned only one time in many decades at high severity, or a site that burned at low severity but multiple times in the same time period. However, high burn severity may predispose areas to more frequent fire because they have

  16. Are soil mite assemblages structured by the identity of native and invasive alien grasses?

    Science.gov (United States)

    St John, Mark G; Wall, Diana H; Hunt, H William

    2006-05-01

    Associations between plants and animals in aboveground communities are often predictable and specific. This has been exploited for the purposes of estimating the diversity of animal species based on the diversity of plant species. The introduction of invasive alien plants into an ecosystem can result in dramatic changes in both the native plant and animal assemblages. Few data exist at the species level to determine whether belowground animal assemblages share the same degree of association to plants. The hypotheses that soil mites (Acari) form assemblages specifically associated with different native grass species in an unmanipulated natural ecosystem and that invasive alien grasses will impact soil mite assemblage composition in this setting were tested. Soil mites sampled beneath five native and two invasive alien species of grasses at the Konza Prairie Biological Station, Kansas, USA, were similarly abundant, species rich, diverse, and taxonomically distinct. No mite species had affinities for a specific grass species. There was no evidence from analysis of similarity, canonical correspondence analysis, or a nonparametric assemblage analysis that the assemblage composition of soil mites was specific to grass species. Results suggest that soil mite assemblages were more related to characteristics of the plant assemblage as a whole or prevailing soil conditions. The most recent invasive alien grass did not support a successionally younger mite fauna, based on the ratio of mesostigmatid to oribatid mites, and neither of the two invasive grasses influenced mite assemblage structure, possibly because they had not yet substantially altered the soil environment. Our results suggest that extrapolations of soil mite diversity based on assumptions of plant specificity would be invalid.

  17. Invasive Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna.

    Science.gov (United States)

    Rossiter-Rachor, N A; Setterfield, S A; Douglas, M M; Hutley, L B; Cook, G D; Schmidt, S

    2009-09-01

    Invasion by the African grass Andropogon gayanus is drastically altering the understory structure of oligotrophic savannas in tropical Australia. We compared nitrogen (N) relations and phenology of A. gayanus and native grasses to examine the impact of invasion on N cycling and to determine possible reasons for invasiveness of A. gayanus. Andropogon gayanus produced up to 10 and four times more shoot phytomass and root biomass, with up to seven and 2.5 times greater shoot and root N pools than native grass understory. These pronounced differences in phytomass and N pools between A. gayanus and native grasses were associated with an altered N cycle. Most growth occurs in the wet season when, compared with native grasses, dominance of A. gayanus was associated with significantly lower total soil N pools, lower nitrification rates, up to three times lower soil nitrate availability, and up to three times higher soil ammonium availability. Uptake kinetics for different N sources were studied with excised roots of three grass species ex situ. Excised roots of A. gayanus had an over six times higher-uptake rate of ammonium than roots of native grasses, while native grass Eriachne triseta had a three times higher uptake rate of nitrate than A. gayanus. We hypothesize that A. gayanus stimulates ammonification but inhibits nitrification, as was shown to occur in its native range in Africa, and that this modification of the soil N cycle is linked to the species' preference for ammonium as an N source. This mechanism could result in altered soil N relations and could enhance the competitive superiority and persistence of A. gayanus in Australian savannas.

  18. UAVs and Machine Learning Revolutionising Invasive Grass and Vegetation Surveys in Remote Arid Lands

    Directory of Open Access Journals (Sweden)

    Juan Sandino

    2018-02-01

    Full Text Available The monitoring of invasive grasses and vegetation in remote areas is challenging, costly, and on the ground sometimes dangerous. Satellite and manned aircraft surveys can assist but their use may be limited due to the ground sampling resolution or cloud cover. Straightforward and accurate surveillance methods are needed to quantify rates of grass invasion, offer appropriate vegetation tracking reports, and apply optimal control methods. This paper presents a pipeline process to detect and generate a pixel-wise segmentation of invasive grasses, using buffel grass (Cenchrus ciliaris and spinifex (Triodia sp. as examples. The process integrates unmanned aerial vehicles (UAVs also commonly known as drones, high-resolution red, green, blue colour model (RGB cameras, and a data processing approach based on machine learning algorithms. The methods are illustrated with data acquired in Cape Range National Park, Western Australia (WA, Australia, orthorectified in Agisoft Photoscan Pro, and processed in Python programming language, scikit-learn, and eXtreme Gradient Boosting (XGBoost libraries. In total, 342,626 samples were extracted from the obtained data set and labelled into six classes. Segmentation results provided an individual detection rate of 97% for buffel grass and 96% for spinifex, with a global multiclass pixel-wise detection rate of 97%. Obtained results were robust against illumination changes, object rotation, occlusion, background cluttering, and floral density variation.

  19. UAVs and Machine Learning Revolutionising Invasive Grass and Vegetation Surveys in Remote Arid Lands.

    Science.gov (United States)

    Sandino, Juan; Gonzalez, Felipe; Mengersen, Kerrie; Gaston, Kevin J

    2018-02-16

    The monitoring of invasive grasses and vegetation in remote areas is challenging, costly, and on the ground sometimes dangerous. Satellite and manned aircraft surveys can assist but their use may be limited due to the ground sampling resolution or cloud cover. Straightforward and accurate surveillance methods are needed to quantify rates of grass invasion, offer appropriate vegetation tracking reports, and apply optimal control methods. This paper presents a pipeline process to detect and generate a pixel-wise segmentation of invasive grasses, using buffel grass (Cenchrus ciliaris) and spinifex (Triodia sp.) as examples. The process integrates unmanned aerial vehicles (UAVs) also commonly known as drones, high-resolution red, green, blue colour model (RGB) cameras, and a data processing approach based on machine learning algorithms. The methods are illustrated with data acquired in Cape Range National Park, Western Australia (WA), Australia, orthorectified in Agisoft Photoscan Pro, and processed in Python programming language, scikit-learn, and eXtreme Gradient Boosting (XGBoost) libraries. In total, 342,626 samples were extracted from the obtained data set and labelled into six classes. Segmentation results provided an individual detection rate of 97% for buffel grass and 96% for spinifex, with a global multiclass pixel-wise detection rate of 97%. Obtained results were robust against illumination changes, object rotation, occlusion, background cluttering, and floral density variation.

  20. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    International Nuclear Information System (INIS)

    Koteen, Laura E; Harte, John; Baldocchi, Dennis D

    2011-01-01

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  1. UAVs and Machine Learning Revolutionising Invasive Grass and Vegetation Surveys in Remote Arid Lands

    Science.gov (United States)

    2018-01-01

    The monitoring of invasive grasses and vegetation in remote areas is challenging, costly, and on the ground sometimes dangerous. Satellite and manned aircraft surveys can assist but their use may be limited due to the ground sampling resolution or cloud cover. Straightforward and accurate surveillance methods are needed to quantify rates of grass invasion, offer appropriate vegetation tracking reports, and apply optimal control methods. This paper presents a pipeline process to detect and generate a pixel-wise segmentation of invasive grasses, using buffel grass (Cenchrus ciliaris) and spinifex (Triodia sp.) as examples. The process integrates unmanned aerial vehicles (UAVs) also commonly known as drones, high-resolution red, green, blue colour model (RGB) cameras, and a data processing approach based on machine learning algorithms. The methods are illustrated with data acquired in Cape Range National Park, Western Australia (WA), Australia, orthorectified in Agisoft Photoscan Pro, and processed in Python programming language, scikit-learn, and eXtreme Gradient Boosting (XGBoost) libraries. In total, 342,626 samples were extracted from the obtained data set and labelled into six classes. Segmentation results provided an individual detection rate of 97% for buffel grass and 96% for spinifex, with a global multiclass pixel-wise detection rate of 97%. Obtained results were robust against illumination changes, object rotation, occlusion, background cluttering, and floral density variation. PMID:29462912

  2. Leaf litter traits of invasive alien species slow down decomposition compared to Spanish natives: a broad phylogenetic comparison.

    NARCIS (Netherlands)

    Godoy, O.; Castro Diez, P.; van Logtestijn, R.S.P; Cornelissen, J.H.C.; Valladares, F.

    2010-01-01

    Leaf traits related to the performance of invasive alien species can influence nutrient cycling through litter decomposition. However, there is no consensus yet about whether there are consistent differences in functional leaf traits between invasive and native species that also manifest themselves

  3. Community structure affects annual grass weed invasion during restoration of a shrub-steppe ecosystem

    Science.gov (United States)

    Phil S. Allen; Susan E. Meyer

    2014-01-01

    Ecological restoration of shrub-steppe communities in the western United States is often hampered by invasion of exotic annual grasses during the process. An important question is how to create restored communities that can better resist reinvasion by these weeds. One hypothesis is that communities comprised of species that are functionally similar to the invader will...

  4. Ecophysiological Responses of Invasive and Native Grass Communities with Simulated Warming

    Science.gov (United States)

    Quade, B.; Ravi, S.; Huxman, T. E.

    2010-12-01

    William Quade1, Sujith Ravi2, Ashley Weide2, Greg Barron-Gafford2, Katerina Dontsova2 and Travis E Huxman2 1Carthage College, WI 2 B2 Earthscience & UA Biosphere 2, University of Arizona, Tucson. Abstract Climate change, anthropogenic disturbances and lack of proper management practices have rendered many arid regions susceptible to invasions by exotic grasses with consequent ecohydrological, biogeochemical and socio economic implications. Thus, understanding the ecophysiological processes driving these large-scale vegetation shifts in drylands, in the context of rising temperatures and recurrent droughts is fundamental to global change research. Using the Biosphere 2 facility to maintain distinct temperature treatments of ambient and predicted warmer conditions (+ 4o C) inside, we compared the physiological (e.g. photosynthesis, stomatal conductance, biomass) responses of a native grass - Heteropogan contortus (Tanglehead) and an invasive grass - Pennisetum ciliare (Buffelgrass) growing in single and mixed communities. The results indicate that Buffelgrass can assimilate more CO2 per unit leaf area under current conditions, though warming seems to inhibit the performance when looking at biomass, photosynthesis and stomatal conductance. Under similar moisture regimes Buffelgrass performed better than Tangle head in mixed communities regardless of the temperature. Both grasses had decrease in stomatal conductance with warmer conditions, however the Buffel grass did not have the same decrease of conductance when planted in a mixed communities. Key words: Buffelgrass, Tanglehead, Biosphere 2, stomatal conductance, climate change

  5. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

    Science.gov (United States)

    Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

    2006-01-01

    Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

  6. An invasive wetland grass primes deep soil carbon pools.

    Science.gov (United States)

    Bernal, Blanca; Megonigal, J Patrick; Mozdzer, Thomas J

    2017-05-01

    Understanding the processes that control deep soil carbon (C) dynamics and accumulation is of key importance, given the relevance of soil organic matter (SOM) as a vast C pool and climate change buffer. Methodological constraints of measuring SOM decomposition in the field prevent the addressing of real-time rhizosphere effects that regulate nutrient cycling and SOM decomposition. An invasive lineage of Phragmites australis roots deeper than native vegetation (Schoenoplectus americanus and Spartina patens) in coastal marshes of North America and has potential to dramatically alter C cycling and accumulation in these ecosystems. To evaluate the effect of deep rooting on SOM decomposition we designed a mesocosm experiment that differentiates between plant-derived, surface SOM-derived (0-40 cm, active root zone of native marsh vegetation), and deep SOM-derived mineralization (40-80 cm, below active root zone of native vegetation). We found invasive P. australis allocated the highest proportion of roots in deeper soils, differing significantly from the native vegetation in root : shoot ratio and belowground biomass allocation. About half of the CO 2 produced came from plant tissue mineralization in invasive and native communities; the rest of the CO 2 was produced from SOM mineralization (priming). Under P. australis, 35% of the CO 2 was produced from deep SOM priming and 9% from surface SOM. In the native community, 9% was produced from deep SOM priming and 44% from surface SOM. SOM priming in the native community was proportional to belowground biomass, while P. australis showed much higher priming with less belowground biomass. If P. australis deep rooting favors the decomposition of deep-buried SOM accumulated under native vegetation, P. australis invasion into a wetland could fundamentally change SOM dynamics and lead to the loss of the C pool that was previously sequestered at depth under the native vegetation, thereby altering the function of a wetland

  7. Spread of common native and invasive grasses and ruderal trees following anthropogenic disturbances in a tropical dry forest

    Science.gov (United States)

    Xavier A. Jaime; Skip J. Van Bloem; Frank H. Koch; Stacy A. C. Nelson

    2017-01-01

    Introduction: A fundamental challenge to the integrity of tropical dry forest ecosystems is the invasion of nonnative grass species. These grasses compete for resources and fuel anthropogenic wildfires. In 2012, a bulldozer from the Puerto Rico Electric Power Authority cleared a 570-m trail from a state road into a mature dry forest section...

  8. Enhancing extension education recommendations to minimize spread of invasive species and establish new grasses for Georgia roadsides : final report.

    Science.gov (United States)

    2015-05-01

    Current DOT management practices could be contributing to the release of invasive : weeds, such as broomsedge and vaseygrass, on Georgia roadsides. The herbicide imazapic, used to : reduce mowing requirements of roadside grasses, injured bermudagrass...

  9. Litter chemistry, community shift, and non-additive effects drive litter decomposition changes following invasion by a generalist pathogen

    Science.gov (United States)

    Richard C. Cobb; David M. Rizzo

    2016-01-01

    Forest pathogens have strong potential to shape ecosystem function by altering litterfall, microclimate, and changing community structure. We quantified changes in litter decomposition from a set of distinct diseases caused by Phytophthora ramorum, an exotic generalist pathogen. Phytophthora ramorum causes leaf blight and...

  10. Management techniques for the control of Melinis minutiflora P. Beauv. (molasses grass: ten years of research on an invasive grass species in the Brazilian Cerrado

    Directory of Open Access Journals (Sweden)

    Carlos Romero Martins

    2017-09-01

    Full Text Available ABSTRACT The invasion of exotic species is considered to be a major threat to the preservation of biodiversity. In the Parque Nacional de Brasília (National Park of Brasília, the invasive Melinis minutiflora (molasses grass occupies more than 10 % of the area of the park. The present, long-term, study compared two treatments of exposure to molasses grass: 1 fire and 2 integrated management (fire + herbicide sprays + manual removal. The aerial biomass of molasses grass in the experimental area initially represented ca. 55 % of the total aerial biomass, a percentage that apparently did not influence native plant species richness at this site. Fire alone was not sufficient to control molasses grass, which attained its pre-treatment biomass values after two years. Integrated management reduced, and maintained, biomass to less than 1 % of its original value after ten years, and maintained this level throughout the study, demonstrating that it is a promising strategy for the recovery of areas invaded by molasses grass in the Cerrado. However, because of the recolonization by molasses grass, long-term monitoring efforts are targeting outbreaks, which would require immediate intervention in order to maintain the native biological diversity of the region.

  11. When perception reflects reality: Non-native grass invasion alters small mammal risk landscapes and survival

    Science.gov (United States)

    Ceradnini, Joseph P.; Chalfoun, Anna

    2017-01-01

    Modification of habitat structure due to invasive plants can alter the risk landscape for wildlife by, for example, changing the quality or availability of refuge habitat. Whether perceived risk corresponds with actual fitness outcomes, however, remains an important open question. We simultaneously measured how habitat changes due to a common invasive grass (cheatgrass, Bromus tectorum) affected the perceived risk, habitat selection, and apparent survival of a small mammal, enabling us to assess how well perceived risk influenced important behaviors and reflected actual risk. We measured perceived risk by nocturnal rodents using a giving-up density foraging experiment with paired shrub (safe) and open (risky) foraging trays in cheatgrass and native habitats. We also evaluated microhabitat selection across a cheatgrass gradient as an additional assay of perceived risk and behavioral responses for deer mice (Peromyscus maniculatus) at two spatial scales of habitat availability. Finally, we used mark-recapture analysis to quantify deer mouse apparent survival across a cheatgrass gradient while accounting for detection probability and other habitat features. In the foraging experiment, shrubs were more important as protective cover in cheatgrass-dominated habitats, suggesting that cheatgrass increased perceived predation risk. Additionally, deer mice avoided cheatgrass and selected shrubs, and marginally avoided native grass, at two spatial scales. Deer mouse apparent survival varied with a cheatgrass–shrub interaction, corresponding with our foraging experiment results, and providing a rare example of a native plant mediating the effects of an invasive plant on wildlife. By synthesizing the results of three individual lines of evidence (foraging behavior, habitat selection, and apparent survival), we provide a rare example of linkage between behavioral responses of animals indicative of perceived predation risk and actual fitness outcomes. Moreover, our results

  12. Invasive species in the flora of the Starobilsk grass-meadow steppe (Ukraine

    Directory of Open Access Journals (Sweden)

    Kucher Oksana O.

    2015-06-01

    Full Text Available The results of an investigation of the invasive species in the flora of the Starobilsk grass-meadow steppe are presented. Check-list of alien plant has over 386 species of vascular plants of which 28 species are invasive. We have identified 6 transformer species from the invasive plants. We aggregate data on the entry, distribution history, ecology, occurrence in different plant communities, degree of their naturalization and the habitats where they occur. The leading families of invasive species are: Asteraceae. The basis for this group is presented by origin from the North America and the Mediterranean. With respect to the time of immigration, most of them are kenophytes. By the method of introduction, ksenophytes are dominated; according to the degree of naturalization epoecophytes and agriophytes dominate in this group. With regard to the characteristics of life forms, half of invasive species are terophytes. The vast majority of plants are heliophytes and xeromesophytes. Most species are found in biotopes group I: Cultivated agricultural biotopes; least of all species found in biotopes group F: Biotopes dominated by chamephytes and nanophanerophytes. Only 3 species found in biotopes group F: Biotopes dominated by chamephytesand nanophanerophytes. The maps of distribution of 28 invasive species are provided. Most of the species marked dispersed in more than 30 squares.

  13. Non-native grass invasion associated with increases in insect diversity in temperate forest understory

    Science.gov (United States)

    Metcalf, Judith L.; Emery, Sarah M.

    2015-11-01

    Invasive plants can alter the structure and function of plant communities to such a degree that they can also have significant impacts on the insect communities. Because insects play an important role in many ecosystems, changes in these communities could have important implications, beyond their biodiversity value, for ecosystem function and diversity at other trophic levels. Microstegium vimineum is an annual C4 grass that is invasive in many eastern North American deciduous forests. Because this grass plays an important role in determining the plant community structure in the understory of these forests, it also has the potential to significantly alter understory insect communities. In this study we evaluated the relationship between M. vimineum and understory insect communities in a forest reserve in Kentucky, USA. Total insect abundance, richness and diversity showed a positive association with M. vimineum presence. Trophic analysis showed significantly higher abundances of herbivores where M. vimineum was present. Forb abundance, which serves as the primary food source for herbivorous insects in this system, was lower in sites invaded with M. vimineum. Invasion by this non-native was also associated with significant increases in aboveground plant biomass which was nearly 50% greater in invaded sites. These results indicate that the understory insect community may be responding to increased biomass rather than the loss of native forb food resources, which contradicts other studies that have examined relationships between M. vimineum invasion and insects. Our results provide evidence that invasive plants can provide benefits for other trophic levels, even when native plant biodiversity is lost.

  14. Does crotalaria (Crotalaria breviflora or pumpkin (Cucurbita moschata inter-row cultivation in restoration plantings control invasive grasses?

    Directory of Open Access Journals (Sweden)

    Ricardo Gomes César

    2013-08-01

    Full Text Available Alternative methods to control invasive fodder grasses are necessary to reduce the use of herbicides in forest restoration, which has been carried out primarily in riparian zones. We sought to investigate if inter-row cultivation of crotalaria (Crotalaria breviflora DC or pumpkin (Cucurbita moschata Duschene ex. Poir with native tree species is an efficient strategy to control invasive fodder grasses in restoration plantings. We tested five treatments in a randomized block design, namely (1 control of brachiaria grass (Urochloa decumbens (Stapf. Webster with glyphosate in the implementation and post-planting grass control of the reforestation, (2 and 3 glyphosate use in the implementation and inter-row sowing of crotalaria (2 or pumpkin (3, and control of brachiaria by mowing in the post-planting phase, (4 and 5 mowing in the implementation and inter-row sowing of crotalaria (4 or pumpkin (5, and control of brachiaria by mowing in the post-planting phase. Post-planting grass control was carried out four and nine months after tree seedling planting. Throughout 13 months, we evaluated the percentage of ground cover by brachiaria grass, pumpkin production, and native tree seedling mortality, height and crown cover. The exclusive use of glyphosate, without inter-row sowing of pumpkin or crotalaria showed the most favorable results for controlling brachiaria grass and, consequently, for tree seedling development. Hence, inter-row cultivation of green manure or short-lived crop species is not enough to control invasive grasses in restoration plantings, and complementary weeding is necessary to reduce the highly competitive potential of C4 grasses for supporting native species seedlings growth.

  15. Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses.

    Science.gov (United States)

    Silvério, Divino V; Brando, Paulo M; Balch, Jennifer K; Putz, Francis E; Nepstad, Daniel C; Oliveira-Santos, Claudinei; Bustamante, Mercedes M C

    2013-06-05

    Changes in climate and land use that interact synergistically to increase fire frequencies and intensities in tropical regions are predicted to drive forests to new grass-dominated stable states. To reveal the mechanisms for such a transition, we established 50 ha plots in a transitional forest in the southwestern Brazilian Amazon to different fire treatments (unburned, burned annually (B1yr) or at 3-year intervals (B3yr)). Over an 8-year period since the commencement of these treatments, we documented: (i) the annual rate of pasture and native grass invasion in response to increasing fire frequency; (ii) the establishment of Brachiaria decumbens (an African C4 grass) as a function of decreasing canopy cover and (iii) the effects of grass fine fuel on fire intensity. Grasses invaded approximately 200 m from the edge into the interiors of burned plots (B1yr: 4.31 ha; B3yr: 4.96 ha) but invaded less than 10 m into the unburned plot (0.33 ha). The probability of B. decumbens establishment increased with seed availability and decreased with leaf area index. Fine fuel loads along the forest edge were more than three times higher in grass-dominated areas, which resulted in especially intense fires. Our results indicate that synergies between fires and invasive C4 grasses jeopardize the future of tropical forests.

  16. Effect of invader litter chemistries on soil organic matter compositions: consequences of Polygonum cuspidatum and Pueraria lobata invasions

    Science.gov (United States)

    Tharayil, N.; Tamura, M.

    2012-12-01

    Carbon fixation during photosynthesis forms the precursor of all organic carbon in soil and the predominant source of energy that drives soil microbial processes; hence the molecular identity of the fixed carbon could influence the formation of soil organic matter (SOM). Due to their high resource acquisition and resource use efficiencies, some invasive plants can input disproportionately high quantities of litter that are qualitatively distinctive, and this could influence the accrual of organic carbon and overall carbon cycling in invaded habitats. Hence, we hypothesized that invasive plants with unique litter chemistries would significantly influence the overall carbon cycling in the invaded soils. We tested this hypothesis by comparing plants exhibiting recalcitrant vs. labile litter chemistries using japanese knotweed (Polygonum cuspidatum) and kudzu (Pueraria lobata), respectively. Japanese knotweed produces low litter abundant in polyphenols which selectively hinders microbially mediated decomposition and re-synthesis; whereas kudzu produces low C:N, high quality litter that can stimulate microbial decomposition. Soil samples were collected at 5-cm intervals and from inside and outside 15 to 20 year old stands of the invasive species. The novelty of our study was that both of our study species were invading into soils of contrasting substrate qualities relative to the invading litter quality. The molecular composition of carbon in the soils and the degradation stage of the SOM were assessed with a biomarker approach using gas chromatography-mass spectrometry to determine the source of biomolecules (plant or microbes). Stability of SOM fractions was assessed through oxidation with hydrogen peroxide, serving as a proxy of biological degradation, followed by stable isotope analysis. Fungal communities dominated the uppermost soils under knotweed whereas kudzu litter suppressed fungal biomass in the top 10-cm. In constrast, increase in active microbial biomass C

  17. Disturbance as a factor in breaking dormancy and enhancing invasiveness of African grasses in a Neotropical Savanna

    OpenAIRE

    Gorgone-Barbosa, Elizabeth; Pivello, Vânia R.; Baeza, M. Jaime; Fidelis, Alessandra

    2016-01-01

    The Cerrado is threatened by wildfires and invasive species. We aimed to evaluate in laboratory conditions whether temperature fluctuation at the soil surface, resulting from the absence of vegetation due to fire, can affect the germination of Urochloa decumbens and U. brizantha, two invasive African grasses. Seeds of both species were submitted to simulations: 1) temperature during fire at 1cm belowground (F); 2) temperature fluctuation at 1cm belowground without vegetation cover for a month...

  18. Resilience to disturbance and resistance to alien grass invasions in the cold desert of western North America

    Science.gov (United States)

    Alien grass invasions are resulting in ecosystem-level transformations of entire landscapes in arid and semi-arid ecosystems. The cold desert of western US is undergoing such a transformation, and is considered one of the most imperiled large ecosystems in the US. To address the rapid and complex ch...

  19. Interactions among climate and soil properties influence current and future geographic distribution of an invasive grass in the Chihuahuan Desert

    Science.gov (United States)

    Background/Question/Methods: Lehmann lovegrass (Eragrostis lehmanniana) is an invasive exotic perennial grass throughout the Sonoran Desert. However, in the neighboring Chihuahuan Desert, this species is generally present in low abundance, although data on its geographic distribution are scarce. Our...

  20. Seasonal variation of soluble carbohydrates and starch in Echinolaena inflexa, a native grass species from the Brazilian savanna, and in the invasive grass Melinis minutiflora

    Directory of Open Access Journals (Sweden)

    A. Souza

    Full Text Available Echinolaena inflexa (Poir. Chase is an abundant C3 grass species with high biomass production in the Brazilian savanna (cerrado; Melinis minutiflora Beauv. is an African C4 forage grass widespread in cerrado and probably displacing some native herbaceous species. In the present work, we analysed seasonally the content and composition of soluble carbohydrates, the starch amounts and the above-ground biomass (phytomass of E. inflexa and M. minutiflora plants harvested in two transects at 5 and 130 m from the border in a restrict area of cerrado at the Biological Reserve and Experimental Station of Mogi-Guaçu (SP, Brazil. Results showed that water soluble carbohydrates and starch amounts from the shoots of both species varied according to the time of the year, whilst in the underground organs, variations were observed mainly in relation to the transects. Marked differences in the pattern of the above-ground biomass production between these two grasses relative to their location in the Reserve were also observed, with two peaks of the invasive species (July and January at the Reserve border. The differences in carbohydrate accumulation, partitioning and composition of individual sugars concerning time of the year and location in the Reserve were more related to the annual growth cycle of both grasses and possibly to specific physiological responses of M. minutiflora to disturbed environments in the Reserve border.

  1. Wildfire, climate, and invasive grass interactions negatively impact an indicator species by reshaping sagebrush ecosystems.

    Science.gov (United States)

    Coates, Peter S; Ricca, Mark A; Prochazka, Brian G; Brooks, Matthew L; Doherty, Kevin E; Kroger, Travis; Blomberg, Erik J; Hagen, Christian A; Casazza, Michael L

    2016-10-25

    Iconic sagebrush ecosystems of the American West are threatened by larger and more frequent wildfires that can kill sagebrush and facilitate invasion by annual grasses, creating a cycle that alters sagebrush ecosystem recovery post disturbance. Thwarting this accelerated grass-fire cycle is at the forefront of current national conservation efforts, yet its impacts on wildlife populations inhabiting these ecosystems have not been quantified rigorously. Within a Bayesian framework, we modeled 30 y of wildfire and climatic effects on population rates of change of a sagebrush-obligate species, the greater sage-grouse, across the Great Basin of western North America. Importantly, our modeling also accounted for variation in sagebrush recovery time post fire as determined by underlying soil properties that influence ecosystem resilience to disturbance and resistance to invasion. Our results demonstrate that the cumulative loss of sagebrush to direct and indirect effects of wildfire has contributed strongly to declining sage-grouse populations over the past 30 y at large spatial scales. Moreover, long-lasting effects from wildfire nullified pulses of sage-grouse population growth that typically follow years of higher precipitation. If wildfire trends continue unabated, model projections indicate sage-grouse populations will be reduced to 43% of their current numbers over the next three decades. Our results provide a timely example of how altered fire regimes are disrupting recovery of sagebrush ecosystems and leading to substantial declines of a widespread indicator species. Accordingly, we present scenario-based stochastic projections to inform conservation actions that may help offset the adverse effects of wildfire on sage-grouse and other wildlife populations.

  2. Decisions, Decisions: Exotic Grass Invasions and Altered Wildfire Regimes in the American Deserts

    Science.gov (United States)

    Betancourt, J. L.

    2009-05-01

    Large-scale invasions by Eurasian and African grasses, brought in by chance or to feed cattle and control erosion, have introduced frequent and extensive fires into American deserts that supported little or no burning in the pre-European era. Based on the fossil record, these have been the fastest, most pervasive and transforming plant invasions of the last 10,000 years. They could easily accelerate with warmer and drier winters and longer and hotter growing seasons in the American West, conspicuous since the mid-1980's and projected to persist with global warming. In cool seasons and wet years that are not usually conducive to wildfires, these invasions are now driving long ignition fronts across long stretches of desertscrub into adjoining woodlands and forests. As such, invasive grasses are capable of changing fire-climate dynamics and altering the entire landscape mosaic. We must now choose between saving the desert or resigning ourselves to these novel and combustible grasslands. In either case, the first line of defense is to immediately adopt an aggressive program of fire suppression in our deserts at a time when we can barely afford to put out forest fires. In the American deserts and adjoining ecosystems, we are standing on a threshold and must now prepare the public for the consequences should those mitigation efforts fail. Both science and management needs should be prioritized to make the best use of limited funding and resources, taking into account the exponential growth of invader abundance, fuel connectivity and fire size as well as projected changes in land use and climate. What is missing is an integrated scientific and political framework vetted and approved by a wide range of stakeholders, with a good chance of sustainable and broadscale success. What decisions must we make, who makes them, and how will they be implemented across complex physical and cultural landscapes? My own take on these issues is that of a federal scientist with a sense of

  3. Simulating long-term effectiveness and efficiency of management scenarios for an invasive grass

    Directory of Open Access Journals (Sweden)

    Catherine S. Jarnevich

    2015-05-01

    Full Text Available Resource managers are often faced with trade-offs in allocating limited resources to manage plant invasions. These decisions must often be made with uncertainty about the location of infestations, their rate of spread and effectiveness of management actions. Landscape level simulation tools such as state-and-transition simulation models (STSMs can be used to evaluate the potential long term consequences of alternative management strategies and help identify those strategies that make efficient use of resources. We analyzed alternative management scenarios for African buffelgrass (Pennisetum ciliare syn. Cenchrus ciliaris at Ironwood Forest National Monument, Arizona using a spatially explicit STSM implemented in the Tool for Exploratory Landscape Scenario Analyses (TELSA. Buffelgrass is an invasive grass that is spreading rapidly in the Sonoran Desert, affecting multiple habitats and jurisdictions. This invasion is creating a novel fire risk and transforming natural ecosystems. The model used in this application incorporates buffelgrass dispersal and establishment and management actions and effectiveness including inventory, treatment and post-treatment maintenance. We simulated 11 alternative scenarios developed in consultation with buffelgrass managers and other stakeholders. The scenarios vary according to the total budget allocated for management and the allocation of that budget between different kinds of management actions. Scenario results suggest that to achieve an actual reduction and stabilization of buffelgrass populations, management unconstrained by fiscal restrictions and across all jurisdictions and private lands is required; without broad and aggressive management, buffelgrass populations are expected to increase over time. However, results also suggest that large upfront investments can achieve control results that require relatively minimal spending in the future. Investing the necessary funds upfront to control the invasion

  4. Global thermal niche models of two European grasses show high invasion risks in Antarctica.

    Science.gov (United States)

    Pertierra, Luis R; Aragón, Pedro; Shaw, Justine D; Bergstrom, Dana M; Terauds, Aleks; Olalla-Tárraga, Miguel Ángel

    2017-07-01

    The two non-native grasses that have established long-term populations in Antarctica (Poa pratensis and Poa annua) were studied from a global multidimensional thermal niche perspective to address the biological invasion risk to Antarctica. These two species exhibit contrasting introduction histories and reproductive strategies and represent two referential case studies of biological invasion processes. We used a multistep process with a range of species distribution modelling techniques (ecological niche factor analysis, multidimensional envelopes, distance/entropy algorithms) together with a suite of thermoclimatic variables, to characterize the potential ranges of these species. Their native bioclimatic thermal envelopes in Eurasia, together with the different naturalized populations across continents, were compared next. The potential niche of P. pratensis was wider at the cold extremes; however, P. annua life history attributes enable it to be a more successful colonizer. We observe that particularly cold summers are a key aspect of the unique Antarctic environment. In consequence, ruderals such as P. annua can quickly expand under such harsh conditions, whereas the more stress-tolerant P. pratensis endures and persist through steady growth. Compiled data on human pressure at the Antarctic Peninsula allowed us to provide site-specific biosecurity risk indicators. We conclude that several areas across the region are vulnerable to invasions from these and other similar species. This can only be visualized in species distribution models (SDMs) when accounting for founder populations that reveal nonanalogous conditions. Results reinforce the need for strict management practices to minimize introductions. Furthermore, our novel set of temperature-based bioclimatic GIS layers for ice-free terrestrial Antarctica provide a mechanism for regional and global species distribution models to be built for other potentially invasive species. © 2017 John Wiley & Sons Ltd.

  5. Simulating long-term effectiveness and efficiency of management scenarios for an invasive grass

    Science.gov (United States)

    Jarnevich, Catherine S.; Holcombe, Tracy R.; Cullinane Thomas, Catherine; Frid, Leonardo; Olsson, Aaryn D.

    2015-01-01

    Resource managers are often faced with trade-offs in allocating limited resources to manage plant invasions. These decisions must often be made with uncertainty about the location of infestations, their rate of spread and effectiveness of management actions. Landscape level simulation tools such as state-and-transition simulation models (STSMs) can be used to evaluate the potential long term consequences of alternative management strategies and help identify those strategies that make efficient use of resources. We analyzed alternative management scenarios for African buffelgrass (Pennisetum ciliare syn. Cenchrus ciliaris) at Ironwood Forest National Monument, Arizona using a spatially explicit STSM implemented in the Tool for Exploratory Landscape Scenario Analyses (TELSA). Buffelgrass is an invasive grass that is spreading rapidly in the Sonoran Desert, affecting multiple habitats and jurisdictions. This invasion is creating a novel fire risk and transforming natural ecosystems. The model used in this application incorporates buffelgrass dispersal and establishment and management actions and effectiveness including inventory, treatment and post-treatment maintenance. We simulated 11 alternative scenarios developed in consultation with buffelgrass managers and other stakeholders. The scenarios vary according to the total budget allocated for management and the allocation of that budget between different kinds of management actions. Scenario results suggest that to achieve an actual reduction and stabilization of buffelgrass populations, management unconstrained by fiscal restrictions and across all jurisdictions and private lands is required; without broad and aggressive management, buffelgrass populations are expected to increase over time. However, results also suggest that large upfront investments can achieve control results that require relatively minimal spending in the future. Investing the necessary funds upfront to control the invasion results in the most

  6. Leaf litter of invasive Chinese tallow (Triadica sebifera) negatively affects hatching success of an aquatic breeding anuran, the southern leopard frog (Lithobates sphenocephalus)

    Science.gov (United States)

    C.K. Adams; D. Saenz

    2012-01-01

    Chinese tallow (Triadica sebifera (L.) Small) is an aggressive invasive tree species that can be abundant in parts of its non-native range. This tree species has the capability of producing monocultures, by outcompeting native trees, which can be in or near wetlands that are utilized by breeding amphibians. Existing research suggests that leaf litter from invasive...

  7. Integrating invasive grasses into carbon cycle projections: Cogongrass spread in southern pine forests

    Science.gov (United States)

    McCabe, T. D.; Flory, S. L.; Wiesner, S.; Dietze, M.

    2017-12-01

    Forested ecosystems are currently being disrupted by invasive species. One example is the invasive grass Imperata cylindrica (cogongrass), which is widespread in southeastern US pine forests. Pines forests dominate the forest cover of the southeast, and contribute to making the Southeast the United States' largest carbon sink. Cogongrass decreases the colonization of loblolly pine fine roots. If cogongrass continues to invade,this sink could be jeopardized. However, the effects of cogongrass invasion on carbon sequestration are largely unknown. We have projected the effects of elevated CO2 and changing climate on future cogongrass invasion. To test how pine stands are affected by cogongrass, cogongrass invasions were modeled using the Ecosystem Demography 2 (ED2) model, and parameterized using the Predictive Ecosystem Analyzer (PEcAn). ED2 takes into account local meteorological data, stand populations and succession, disturbance, and geochemical pools. PEcAn is a workflow that uses Bayesian sensitivity analyses and variance decomposition to quantify the uncertainty that each parameter contributes to overall model uncertainty. ED2 was run for four NEON and Ameriflux sites in the Southeast from the earliest available census of the site into 2010. These model results were compared to site measures to test for model accuracy and bias. To project the effect of elevated CO2 on cogongrass invasions, ED was run from 2006-2100 at four sites under four separate scenarios: 1) RPC4.5 CO2 and climate, 2) RPC4.5 climate only, with constant CO2 concentrations, 3) RPC4.5 Elevated CO2 only, with climate randomly selected from 2006-2026, 4) Present Day, made from randomly selected measures of CO2 and radiation from 2006-2026. Each scenario was run three times; once with cogongrass absent, once with a low cogongrass abundance, and once with a high cogongrass abundance. Model results suggest that many relevant parameters have high uncertainty due to lack of measurement. Further field

  8. Predicting potential global distributions of two Miscanthus grasses: implications for horticulture, biofuel production, and biological invasions.

    Science.gov (United States)

    Hager, Heather A; Sinasac, Sarah E; Gedalof, Ze'ev; Newman, Jonathan A

    2014-01-01

    In many regions, large proportions of the naturalized and invasive non-native floras were originally introduced deliberately by humans. Pest risk assessments are now used in many jurisdictions to regulate the importation of species and usually include an estimation of the potential distribution in the import area. Two species of Asian grass (Miscanthus sacchariflorus and M. sinensis) that were originally introduced to North America as ornamental plants have since escaped cultivation. These species and their hybrid offspring are now receiving attention for large-scale production as biofuel crops in North America and elsewhere. We evaluated their potential global climate suitability for cultivation and potential invasion using the niche model CLIMEX and evaluated the models' sensitivity to the parameter values. We then compared the sensitivity of projections of future climatically suitable area under two climate models and two emissions scenarios. The models indicate that the species have been introduced to most of the potential global climatically suitable areas in the northern but not the southern hemisphere. The more narrowly distributed species (M. sacchariflorus) is more sensitive to changes in model parameters, which could have implications for modelling species of conservation concern. Climate projections indicate likely contractions in potential range in the south, but expansions in the north, particularly in introduced areas where biomass production trials are under way. Climate sensitivity analysis shows that projections differ more between the selected climate change models than between the selected emissions scenarios. Local-scale assessments are required to overlay suitable habitat with climate projections to estimate areas of cultivation potential and invasion risk.

  9. Predicting potential global distributions of two Miscanthus grasses: implications for horticulture, biofuel production, and biological invasions.

    Directory of Open Access Journals (Sweden)

    Heather A Hager

    Full Text Available In many regions, large proportions of the naturalized and invasive non-native floras were originally introduced deliberately by humans. Pest risk assessments are now used in many jurisdictions to regulate the importation of species and usually include an estimation of the potential distribution in the import area. Two species of Asian grass (Miscanthus sacchariflorus and M. sinensis that were originally introduced to North America as ornamental plants have since escaped cultivation. These species and their hybrid offspring are now receiving attention for large-scale production as biofuel crops in North America and elsewhere. We evaluated their potential global climate suitability for cultivation and potential invasion using the niche model CLIMEX and evaluated the models' sensitivity to the parameter values. We then compared the sensitivity of projections of future climatically suitable area under two climate models and two emissions scenarios. The models indicate that the species have been introduced to most of the potential global climatically suitable areas in the northern but not the southern hemisphere. The more narrowly distributed species (M. sacchariflorus is more sensitive to changes in model parameters, which could have implications for modelling species of conservation concern. Climate projections indicate likely contractions in potential range in the south, but expansions in the north, particularly in introduced areas where biomass production trials are under way. Climate sensitivity analysis shows that projections differ more between the selected climate change models than between the selected emissions scenarios. Local-scale assessments are required to overlay suitable habitat with climate projections to estimate areas of cultivation potential and invasion risk.

  10. Decomposition of leaf litter from a native tree and an actinorhizal invasive across riparian habitats.

    Science.gov (United States)

    Harner, Mary J; Crenshaw, Chelsea L; Abelho, Manuela; Stursova, Martina; Shah, Jennifer J Follstad; Sinsabaugh, Robert L

    2009-07-01

    Dynamics of nutrient exchange between floodplains and rivers have been altered by changes in flow management and proliferation of nonnative plants. We tested the hypothesis that the nonnative, actinorhizal tree, Russian olive (Elaeagnus angustifolia), alters dynamics of leaf litter decomposition compared to native cottonwood (Populus deltoides ssp. wislizeni) along the Rio Grande, a river with a modified flow regime, in central New Mexico (U.S.A.). Leaf litter was placed in the river channel and the surface and subsurface horizons of forest soil at seven riparian sites that differed in their hydrologic connection to the river. All sites had a cottonwood canopy with a Russian olive-dominated understory. Mass loss rates, nutrient content, fungal biomass, extracellular enzyme activities (EEA), and macroinvertebrate colonization were followed for three months in the river and one year in forests. Initial nitrogen (N) content of Russian olive litter (2.2%) was more than four times that of cottonwood (0.5%). Mass loss rates (k; in units of d(-1)) were greatest in the river (Russian olive, k = 0.0249; cottonwood, k = 0.0226), intermediate in subsurface soil (Russian olive, k = 0.0072; cottonwood, k = 0.0031), and slowest on the soil surface (Russian olive, k = 0.0034; cottonwood, k = 0.0012) in a ratio of about 10:2:1. Rates of mass loss in the river were indistinguishable between species and proportional to macroinvertebrate colonization. In the riparian forest, Russian olive decayed significantly faster than cottonwood in both soil horizons. Terrestrial decomposition rates were related positively to EEA, fungal biomass, and litter N, whereas differences among floodplain sites were related to hydrologic connectivity with the river. Because nutrient exchanges between riparian forests and the river have been constrained by flow management, Russian olive litter represents a significant annual input of N to riparian forests, which now retain a large portion of slowly

  11. Feasibility of Invasive Grass Detection in a Desertscrub Community Using Hyperspectral Field Measurements and Landsat TM Imagery

    Directory of Open Access Journals (Sweden)

    Stuart E. Marsh

    2011-10-01

    Full Text Available Invasive species’ phenologies often contrast with those of native species, representing opportunities for detection of invasive species with multi-temporal remote sensing. Detection is especially critical for ecosystem-transforming species that facilitate changes in disturbance regimes. The African C4 grass, Pennisetum ciliare, is transforming ecosystems on three continents and a number of neotropical islands by introducing a grass-fire cycle. However, previous attempts at discriminating P. ciliare in North America using multi-spectral imagery have been unsuccessful. In this paper, we integrate field measurements of hyperspectral plant species signatures and canopy cover with multi-temporal spectral analysis to identify opportunities for detection using moderate-resolution multi-spectral imagery. By applying these results to Landsat TM imagery, we show that multi-spectral discrimination of P. ciliare in heterogeneous mixed desert scrub is feasible, but only at high abundance levels that may have limited value to land managers seeking to control invasion. Much higher discriminability is possible with hyperspectral shortwave infrared imagery because of differences in non-photosynthetic vegetation in uninvaded and invaded landscapes during dormant seasons but these spectra are unavailable in multispectral sensors. Therefore, we recommend hyperspectral imagery for distinguishing invasive grass-dominated landscapes from uninvaded desert scrub.

  12. Annual grass invasion in sagebrush-steppe: The relative importance of climate, soil properties and biotic interactions

    Science.gov (United States)

    Bansal, Sheel; Sheley, Roger L.

    2016-01-01

    The invasion by winter-annual grasses (AGs) such as Bromus tectorum into sagebrush steppe throughout the western USA is a classic example of a biological invasion with multiple, interacting climate, soil and biotic factors driving the invasion, although few studies have examined all components together. Across a 6000-km2 area of the northern Great Basin, we conducted a field assessment of 100 climate, soil, and biotic (functional group abundances, diversity) factors at each of 90 sites that spanned an invasion gradient ranging from 0 to 100 % AG cover. We first determined which biotic and abiotic factors had the strongest correlative relationships with AGs and each resident functional group. We then used regression and structural equation modeling to explore how multiple ecological factors interact to influence AG abundance. Among biotic interactions, we observed negative relationships between AGs and biodiversity, perennial grass cover, resident species richness, biological soil crust cover and shrub density, whereas perennial and annual forb cover, tree cover and soil microbial biomass had no direct linkage to AG. Among abiotic factors, AG cover was strongly related to climate (increasing cover with increasing temperature and aridity), but had weak relationships with soil factors. Our structural equation model showed negative effects of perennial grasses and biodiversity on AG cover while integrating the negative effects of warmer climate and positive influence of belowground processes on resident functional groups. Our findings illustrate the relative importance of biotic interactions and climate on invasive abundance, while soil properties appear to have stronger relationships with resident biota than with invasives.

  13. Indaziflam: a new cellulose-biosynthesis-inhibiting herbicide provides long-term control of invasive winter annual grasses.

    Science.gov (United States)

    Sebastian, Derek J; Fleming, Margaret B; Patterson, Eric L; Sebastian, James R; Nissen, Scott J

    2017-10-01

    Indaziflam is a cellulose-biosynthesis-inhibiting (CBI) herbicide that is a unique mode of action for resistance management and has broad spectrum activity at low application rates. This research further explores indaziflam's activity on monocotyledons and dicotyledons and evaluates indaziflam's potential for restoring non-crop sites infested with invasive winter annual grasses. Treated Arabidopsis, downy brome, feral rye and kochia were all susceptible to indaziflam in a dose-dependent manner. We confirmed that indaziflam has increased activity on monocots (average GR 50  = 231 pm and 0.38 g AI ha -1 ) at reduced concentrations compared with dicots (average GR 50  = 512 pm and 0.87 g AI ha -1 ). Fluorescence microscopy confirmed common CBI symptomologies following indaziflam treatments, as well as aberrant root and cell morphology. Across five application timings, indaziflam treatments resulted in superior invasive winter annual grass control 2 years after treatment (from 84 ± 5.1% to 99 ± 0.5%) compared with imazapic (36% ± 1.2%). Indaziflam treatments significantly increased biomass and species richness of co-occurring species 2 years after treatment. Indaziflam's increased activity on monocots could provide a new alternative management strategy for long-term control of multiple invasive winter annual grasses that invade >23 million ha of US rangeland. Indaziflam could potentially be used to eliminate the soil seed bank of these invasive grasses, reduce fine fuel accumulation and ultimately increase the competitiveness of perennial co-occuring species. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Density-dependent role of an invasive marsh grass, Phragmites australis, on ecosystem service provision.

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    Seth J Theuerkauf

    Full Text Available Invasive species can positively, neutrally, or negatively affect the provision of ecosystem services. The direction and magnitude of this effect can be a function of the invaders' density and the service(s of interest. We assessed the density-dependent effect of an invasive marsh grass, Phragmites australis, on three ecosystem services (plant diversity and community structure, shoreline stabilization, and carbon storage in two oligohaline marshes within the North Carolina Coastal Reserve and National Estuarine Research Reserve System (NCNERR, USA. Plant species richness was equivalent among low, medium and high Phragmites density plots, and overall plant community composition did not vary significantly by Phragmites density. Shoreline change was most negative (landward retreat where Phragmites density was highest (-0.40 ± 0.19 m yr-1 vs. -0.31 ± 0.10 for low density Phragmites in the high energy marsh of Kitty Hawk Woods Reserve and most positive (soundward advance where Phragmites density was highest (0.19 ± 0.05 m yr-1 vs. 0.12 ± 0.07 for low density Phragmites in the lower energy marsh of Currituck Banks Reserve, although there was no significant effect of Phragmites density on shoreline change. In Currituck Banks, mean soil carbon content was approximately equivalent in cores extracted from low and high Phragmites density plots (23.23 ± 2.0 kg C m-3 vs. 22.81 ± 3.8. In Kitty Hawk Woods, mean soil carbon content was greater in low Phragmites density plots (36.63 ± 10.22 kg C m-3 than those with medium (13.99 ± 1.23 kg C m-3 or high density (21.61 ± 4.53 kg C m-3, but differences were not significant. These findings suggest an overall neutral density-dependent effect of Phragmites on three ecosystem services within two oligohaline marshes in different environmental settings within a protected reserve system. Moreover, the conceptual framework of this study can broadly inform an ecosystem services-based approach to invasive species

  15. Leaf-litter inputs from an invasive nitrogen-fixing tree influence organic-matter dynamics and nitrogen inputs in a Hawaiian river

    Science.gov (United States)

    Richard A. MacKenzie; Tracy N. Wiegner; Frances Kinslow; Nicole Cormier; Ayron M. Strauch

    2013-01-01

    Abstract. We examined how invasion of tropical riparian forests by an exotic N-fixing tree (Falcataria moluccana) affects organic-matter dynamics in a Hawaiian river by comparing early stages of leaf-litter breakdown between the exotic F. moluccana and native Metrosideros polymorpha trees. We examined early...

  16. Plastic responses of native plant root systems to the presence of an invasive annual grass.

    Science.gov (United States)

    Phillips, Allison J; Leger, Elizabeth A

    2015-01-01

    • The ability to respond to environmental change via phenotypic plasticity may be important for plants experiencing disturbances such as climate change and plant invasion. Responding to belowground competition through root plasticity may allow native plants to persist in highly invaded systems such as the cold deserts of the Intermountain West, USA.• We investigated whether Poa secunda, a native bunchgrass, could alter root morphology in response to nutrient availability and the presence of a competitive annual grass. Seeds from 20 families were grown with high and low nutrients and harvested after 50 d, and seeds from 48 families, grown with and without Bromus tectorum, were harvested after ∼2 or 6 mo. We measured total biomass, root mass fraction, specific root length (SRL), root tips, allocation to roots of varying diameter, and plasticity in allocation.• Plants had many parallel responses to low nutrients and competition, including increased root tip production, a trait associated with tolerance to reduced resources, though families differed in almost every trait and correlations among trait changes varied among experiments, indicating flexibility in plant responses. Seedlings actively increased SRL and fine root allocation under competition, while older seedlings also increased coarse root allocation, a trait associated with increased tolerance, and increased root mass fraction.• The high degree of genetic variation for root plasticity within natural populations could aid in the long-term persistence of P. secunda because phenotypic plasticity may allow native species to persist in invaded and fluctuating resource environments. © 2015 Botanical Society of America, Inc.

  17. Monitoring the Distribution and Dynamics of an Invasive Grass in Tropical Savanna Using Airborne LiDAR

    Directory of Open Access Journals (Sweden)

    Shaun R. Levick

    2015-04-01

    Full Text Available The spread of an alien invasive grass (gamba grass—Andropogon gayanus in the tropical savannas of Northern Australia is a major threat to habitat quality and biodiversity in the region, primarily through its influence on fire intensity. Effective control and eradication of this invader requires better insight into its spatial distribution and rate of spread to inform management actions. We used full-waveform airborne LiDAR to map areas of known A. gayanus invasion in the Batchelor region of the Northern Territory, Australia. Our stratified sampling campaign included wooded savanna areas with differing degrees of A. gayanus invasion and adjacent areas of native grass and woody tree mixtures. We used height and spatial contiguity based metrics to classify returns from A. gayanus and developed spatial representations of A. gayanus occurrence (1 m resolution and canopy cover (10 m resolution. The cover classification proved robust against two independent field-based investigations at 500 m2 (R2 = 0.87, RMSE = 12.53 and 100 m2 (R2 = 0.79, RMSE = 14.13 scale. Our mapping results provide a solid benchmark for evaluating the rate and pattern of A. gayanus spread from future LiDAR campaigns. In addition, this high-resolution mapping can be used to inform satellite image analysis for the evaluation of A. gayanus invasion over broader regional scales. Our research highlights the huge potential that airborne LiDAR holds for facilitating the monitoring and management of savanna habitat condition.

  18. Impacts of invasive riparian knotweed on litter decomposition, aquatic fungi, and macroinvertebrates

    Science.gov (United States)

    Shannon M. Claeson; Carri J. LeRoy; Jacob R. Barry; Kevin A. Kuehn

    2014-01-01

    Bohemian knotweed (Polygonum X bohemicum), the hybrid between Japanese and giant knotweed, is the most common invasive knotweed species in western North America and the most difficult to control. Invasive knotweed congeners spread aggressively along streams and establish dense monotypic stands, reducing riparian plant species diversity....

  19. Effects of invasive European bird cherry (Prunus padus) on leaf litter processing by aquatic invertebrate shredder communities in urban Alaskan streams

    Science.gov (United States)

    Roon, David A.; Wipfli, Mark S.; Wurtz, Tricia L.

    2014-01-01

    European bird cherry (Prunus padus) (EBC) is an invasive ornamental tree that is spreading rapidly in riparian forests of urban Alaska. To determine how the spread of EBC affects leaf litter processing by aquatic invertebrate shredders, we conducted complementary leaf pack experiments in two streams located in Anchorage, Alaska. The first experiment contrasted invasive EBC with three native tree species—thin-leaf alder (Alnus tenuifolia), paper birch (Betula neoalaskana), and black cottonwood (Populus trichocarpa)—in one reach of Chester Creek; finding that EBC leaf litter broke down significantly faster than birch and cottonwood, but at a similar rate to alder. The second experiment contrasted EBC with alder in four reaches of Campbell and Chester creeks; finding that while EBC leaf litter broke down significantly faster than alder in Chester Creek, EBC broke down at a similar rate to alder in Campbell Creek. Although EBC sometimes supported fewer shredders by both count and mass, shredder communities did not differ significantly between EBC and native plants. Collectively, these data suggest that invasive EBC is not currently exhibiting strong negative impacts on leaf litter processing in these streams, but could if it continues to spread and further displaces native species over time.

  20. Long-term ecological consequences of herbicide treatment to control the invasive grass, Spartina anglica, in an Australian saltmarsh

    Science.gov (United States)

    Shimeta, Jeff; Saint, Lynnette; Verspaandonk, Emily R.; Nugegoda, Dayanthi; Howe, Steffan

    2016-07-01

    Invasive plants acting as habitat modifiers in coastal wetlands can have extensive ecological impacts. Control of invasive plants often relies on herbicides, although little is known about subsequent environmental impacts. Studying effects of herbicides on non-target species and long-term cascading consequences may yield insights into the ecology of invasive species by revealing interactions with native species. We conducted a long-term field experiment measuring effects of treating the invasive saltmarsh grass, Spartina anglica, with the herbicide Fusilade Forte®. No changes in sedimentary macrofaunal abundances or species richness, diversity, or assemblages were detected 1-2 months after spraying, despite known toxicity of Fusilade Forte® to fauna. This lack of impact may have been due to low exposure, since the herbicide was taken up primarily by plant leaves, with the small amount that reached the sediment hydrolyzing rapidly. Six months after spraying, however, total macrofauna in treated plots was more than four times more abundant than in unsprayed control plots, due to a fifteen-fold increase in annelids. This population growth correlated with increased sedimentary organic matter in treated plots, likely due to decomposition of dead S. anglica leaves serving as food for annelids. After another year, no differences in macrofauna or organic matter remained between treatments. The indirect effect on annelid populations from herbicide treatment could benefit management efforts by providing greater food resources for wading birds, in addition to improving birds' access to sediments by reducing plant cover. This study shows that an invasive grass can have a significant impact on native fauna through food-web interactions, influenced by herbicide usage.

  1. Direct effects of soil amendments on field emergence and growth of the invasive annual grass Bromus tectorum L. and the native perennial grass Hilaria jamesii (Torr.) Benth

    Science.gov (United States)

    Newingham, B.A.; Belnap, J.

    2006-01-01

    Bromus tectorum L. is a non-native, annual grass that has invaded western North America. In SE Utah, B. tectorum generally occurs in grasslands dominated by the native perennial grass, Hilaria jamesii (Torr.) Benth. and rarely where the natives Stipa hymenoides Roem. and Schult. and S. comata Trin. & Rupr. are dominant. This patchy invasion is likely due to differences in soil chemistry. Previous laboratory experiments investigated using soil amendments that would allow B. tectorum to germinate but would reduce B. tectorum emergence without affecting H. jamesii. For this study we selected the most successful treatments (CaCl2, MgCl2, NaCl and zeolite) from a previous laboratory study and applied them in the field in two different years at B. tectorum-dominated field sites. All amendments except the lowest level of CaCl2 and zeolite negatively affected B. tectorum emergence and/or biomass. No amendments negatively affected the biomass of H. jamesii but NaCl reduced emergence. Amendment effectiveness depended on year of application and the length of time since application. The medium concentration of zeolite had the strongest negative effect on B. tectorum with little effect on H. jamesii. We conducted a laboratory experiment to determine why zeolite was effective and found it released large amounts of Na+, adsorbed Ca2+, and increased Zn2+, Fe2+, Mn2+, Cu2+, exchangeable Mg2+, exchangeable K, and NH 4+ in the soil. Our results suggest several possible amendments to control B. tectorum. However, variability in effectiveness due to abiotic factors such as precipitation and soil type must be accounted for when establishing management plans. ?? Springer 2006.

  2. Exotic Annual Grasses in Western Rangelands: Predicting Resistance and Resilience of Native Ecosystems to Invasion (Draft)

    Science.gov (United States)

    2004-04-22

    from leaf litter can improve the growth of dipterocarp seedlings. - New Phytologist 160: 101-110. Callaway, R. M., Nadkarni , N. M. and Mahall, B. E... Sr ., T. G. F. Kittel, and J. S. Baron. 1998. Evidence that local land use practices influence regional climate, vegetation, and stream flow patterns

  3. The indirect effects of cheatgrass invasion: Grasshopper herbivory on native grasses determined by neighboring cheatgrass abundance

    Science.gov (United States)

    Julie Beckstead; Susan E. Meyer; Carol K. Augsperger

    2008-01-01

    Invasion biology has focused on the direct effects of plant invasion and has generally overlooked indirect interactions. Here we link theories of invasion biology and herbivory to explore an indirect effect of one invading species on associational herbivory (the effect of neighboring plants on herbivory) of native species. We studied a Great Basin shadscale (...

  4. Disturbance as a factor in breaking dormancy and enhancing invasiveness of African grasses in a Neotropical Savanna

    Directory of Open Access Journals (Sweden)

    Elizabeth Gorgone-Barbosa

    2016-03-01

    Full Text Available The Cerrado is threatened by wildfires and invasive species. We aimed to evaluate in laboratory conditions whether temperature fluctuation at the soil surface, resulting from the absence of vegetation due to fire, can affect the germination of Urochloa decumbens and U. brizantha, two invasive African grasses. Seeds of both species were submitted to simulations: 1 temperature during fire at 1cm belowground (F; 2 temperature fluctuation at 1cm belowground without vegetation cover for a month (TF; 3 (F + (TF; 4 control at 25ºC. After treatments, seeds were put to germinate at 25ºC for 40 days. We had four replicates per treatment and three temporal replicates. We compared germination percentage and the mean germination time among treatments using ANOVA. The treatments TF and F+TF had the highest germination values for both species. The results showed that fire per se could not stimulate seed germination, however, they suggest that a disturbance that produces a pattern of temperature fluctuation is able to break dormancy and enhance seed germination and, consequently, increase the invasiveness of the study species. Vegetation gaps resulting from disturbance may become new sites of invasion. This information is important for making management decisions regarding the control of these species.

  5. Katkor(R cat litter, a non-invasive method of collecting cat urine for phosphate determination : short communication

    Directory of Open Access Journals (Sweden)

    P.C. Delport

    2005-06-01

    Full Text Available This study was done to compare the collection of cat urine, for phosphate concentration determination, by catheterisation with that via a proprietary cat litter (Katkor (R. The passage of urine through the litter or its retention in the litter for a period of 2 hours did not affect the concentration of phosphates compared with that of the original sample. Apart from a small volume of urine trapped in the litter by capillary action, and some urine adhering to the funnel in which the litter was placed, the litter proved to be an excellent medium for routine urine collection from cats, and more especially as an alternative to catheterisation when regular collection from a particular cat is required.

  6. Influence of invasive Acer negundo leaf litter on benthic microbial abundance and activity in the littoral zone of a temperate river in Lithuania

    Directory of Open Access Journals (Sweden)

    Krevš Alina

    2017-01-01

    Full Text Available Riparian forests are known as important source of allochthonous organic matter entering to water ecosystems via fallen leaves. However, leaf litter, depending on their quality, may create different conditions for benthic microorganisms functioning in littoral zone of water bodies. In order to evaluate the impact of riparian invasive Acer negundo on littoral water zone of the River Neris (Lithuania, we performed physicochemical and microbiological investigations in bottom sediments of three different sites of the river. One sampling site was close by riparian A. negundo, another close by native Alnus glutinosa location and a third zone was near the shore without riparian vegetation. Content of nutrients in the littoral sediments differed between invasive and native trees leaf litter accumulation sites, while not always significantly. The highest microbial densities as well as benthic community respiratory activity (expressed as the rate of organic carbon mineralization occurred in A. negundo leaves accumulation site. In sediments of this site, the most intensive anaerobic terminal organic carbon mineralization process − sulfate reduction and the highest concentration of hydrogen sulfide were also observed. Differences in the intensity of mineralization processes between sites suggest that the replacement of the riparian native species such as dominant A. glutinosa by invasive A. negundo with higher biodegradability leaves may induce local changes in organic matter processing in the littoral zone of the river. The increase of littoral bioproductivity in the accumulation zone of A. negundo leaf litter can occur due to the inflow of available organic matter and its intensive mineralization.

  7. Using resistance and resilience concepts to reduce impacts of invasive annual grasses and altered fire regimes on the sagebrush ecosystem and greater sage-grouse: A strategic multi-scale approach

    Science.gov (United States)

    Jeanne C. Chambers; David A. Pyke; Jeremy D. Maestas; Mike Pellant; Chad S. Boyd; Steven B. Campbell; Shawn Espinosa; Douglas W. Havlina; Kenneth E. Mayer; Amarina Wuenschel

    2014-01-01

    This Report provides a strategic approach for conservation of sagebrush ecosystems and Greater Sage- Grouse (sage-grouse) that focuses specifically on habitat threats caused by invasive annual grasses and altered fire regimes. It uses information on factors that influence (1) sagebrush ecosystem resilience to disturbance and resistance to invasive annual grasses and (2...

  8. A field guide for rapid assessment of post-wildfire recovery potential in sagebrush and pinon-juniper ecosystems in the Great Basin: Evaluating resilience to disturbance and resistance to invasive annual grasses and predicting vegetation response

    Science.gov (United States)

    Richard F. Miller; Jeanne C. Chambers; Mike Pellant

    2015-01-01

    This field guide provides a framework for rapidly evaluating post-fire resilience to disturbance, or recovery potential, and resistance to invasive annual grasses, and for determining the need and suitability of the burned area for seeding. The framework identifies six primary components that largely determine resilience to disturbance, resistance to invasive grasses,...

  9. The grasses (Poaceae) of the Colombian guayana: analyses on their composition, richness, endemism, and invasion

    International Nuclear Information System (INIS)

    Canas, Diego Giraldo

    2010-01-01

    The checklist of grasses from Colombian Guayana is presented. In all, 152 species, 69 genera, and six subfamilies were recorded. Thus, in the Colombian Guayana is represented the 18.7 and 43.7% of the species and genera of Colombian grasses, respectively. The subfamilies with the highest number of species were Panicoideae (110 species/46 genera), Chloridoideae (21/9), and Bambusoideae (11/9). The most diverse genera were Paspalum (19 species), Panicum (16), Axonopus (14), Eragrostis (9), and Digitaria (8). Nineteen species are introduced and naturalized in the Colombian Guayana, which represent 12.5% of the agrostological flora for the Colombian Guayana. There were 8 endemic species (5.3% of Colombian Guayanan grasses). In addition, some species are reported for the first time for Colombian flora (belonging to Axonopus, Cyphonanthus, Gymnopogon, and Paspalum), and some species are new to science (belonging to Axonopus, Digitaria, Eragrostis, and Sacciolepis). On the other hand, some preliminary biogeographical aspect are analyzed Flora of Colombia,

  10. Variations of selected soil properties in the grass fields invaded and uninvaded by invasive goldenrod (Solidago canadensis L.

    Directory of Open Access Journals (Sweden)

    Baranová Beáta

    2017-06-01

    Full Text Available Although the invasion of exotic plants has been recognised as the serious cause of the biodiversity loss and natural habitats degradation and threat to the ecosystems functions, just the little attention has been paid to the potential impacts of the goldenrod invasion on the soil properties. Equally, currently obtained results are contrary and ambiguous. We tested whether the grass fields invaded and uninvaded by Canadian goldenrod (Solidago canadensis L. differ in pH, soil moisture, organic carbon (Cox, humus and P, K and Mg contents and related the variations to the chosen environmental variables. We did not find significant distinctions of the studied types of habitats in the selected physico-chemical soil properties as well as the relation between the goldenrod invasion and the changes in soil properties. Nevertheless, whereas the soil reaction, soil moisture and Mg content were higher in the invaded soils, the Cox, humus and P and K contents were higher in the uninvaded ones. Doubtless, further attention need to be paid to this problem.

  11. Sparrow nest survival in relation to prescribed fire and woody plant invasion in a northern mixed-grass prairie

    Science.gov (United States)

    Murphy, Robert K.; Shaffer, Terry L.; Grant, Todd A.; Derrig, James L.; Rubin, Cory S.; Kerns, Courtney K.

    2017-01-01

    Prescribed fire is used to reverse invasion by woody vegetation on grasslands, but managers often are uncertain whether influences of shrub and tree reduction outweigh potential effects of fire on nest survival of grassland birds. During the 2001–2003 breeding seasons, we examined relationships of prescribed fire and woody vegetation to nest survival of clay-colored sparrow (Spizella pallida) and Savannah sparrow (Passerculus sandwichensis) in mixed-grass prairie at Des Lacs National Wildlife Refuge in northwestern North Dakota, USA. We assessed relationships of nest survival to 1) recent fire history, in terms of number of breeding seasons (2, 3, or 4–5) since the last prescribed fire, and 2) prevalence of trees and tall (>1.5 m) shrubs in the landscape and of low (≤1.5 m) shrubs within 5 m of nests. Nest survival of both species exhibited distinct patterns related to age of the nest and day of year, but bore no relationship to fire history. Survival of clay-colored sparrow nests declined as the amount of trees and tall shrubs within 100 m increased, but we found no relationship to suggest nest parasitism by brown-headed cowbirds (Molothrus ater) as an underlying mechanism. We found little evidence linking nest survival of Savannah sparrow to woody vegetation. Our results suggest that fire can be used to restore northern mixed-grass prairies without adversely affecting nest survival of ≥2 widespread passerine species. Survival of nests of clay-colored sparrow may increase when tall woody cover is reduced by fire. Our data lend support to the use of fire for reducing scattered patches of tall woody cover to enhance survival of nests of ≥1 grassland bird species in northern mixed-grass prairies, but further study is needed that incorporates experimental approaches and assessments of shorter term effects of fire on survival of nests of grassland passerines.

  12. Sources and modes of action of invasive knotweed allelopathy: the effects of leaf litter and trained soil on the germination and growth of native plants

    Directory of Open Access Journals (Sweden)

    Madalin Parepa

    2012-05-01

    Full Text Available Invasive knotweeds, native to Eastern Asia, are among the most dominant plant invaders of European and North American temperate ecosystems. Recent studies indicate that one cause of this dominance might be allelopathy, but the possible sources and modes of action of this allelopathy are insufficiently understood. Here, we asked whether the invasive knotweed Fallopia × bohemica can exert allelopathic effects on native plants also through its leaf litter, or through persistent soil contaminants, and whether these affect the germination or growth of native plants. In a germination experiment with nine native species neither litter leachate, an aqueous extract of knotweed leaves added to the soil, nor trained soil with a history of Fallopia pre-cultivation suppressed the germination or early growth of natives. A mesocosm study with experimental native communities showed that the presence of F. × bohemica, although not a dominant in these communities, caused significant shifts of life-history strategy in two dominant natives, and that similar effects could be elicited through litter leachates or trained soil alone. However, there were hardly any effects on the biomass of natives. Our study indicates that knotweed allelopathy acts on the growth rather than germination of natives, and that soil contamination through persistent allelochemicals may not be a significant problem in habitat restoration. It also shows that allelopathic effects can sometimes be subtle changes in life-history and allocation patterns of the affected species.

  13. Intraspecific variation among clones of a naïve rare grass affects competition with a nonnative, invasive forb.

    Science.gov (United States)

    Gibson, David J; Dewey, Justin; Goossens, Hélène; Dodd, Misty M

    2014-01-01

    Intraspecific variation can have a major impact on plant community composition yet there is little information available on the extent that such variation by an already established species affects interspecific interactions of an invading species. The current research examined the competitiveness of clones of a globally rare but locally common native grass, Calamagrostis porteri ssp. insperata to invasion by Alliaria petiolata, a non-native invasive species. A greenhouse experiment was conducted twice over consecutive years in which 15 clones from three populations of Calamagrostis were paired with rosettes of Alliaria in pots containing native forest soil previously uninvaded by Alliaria. Both species showed a negative response to the presence of the other species, although Alliaria more so than Calamagrostis. Moreover, the effect of Calamagrostis depended upon population, and, to a lesser extent, the individual clone paired with Alliaria. Competitive effects were stronger in the first experiment compared with when the experiment was repeated in the second year. The influence of Calamagrostis clones on the outcome of the experiment varied among populations and among clones, but also between years. Clones from one of the three populations were more influential than clones from the other two populations. Only one of 15 clones, both from the same population, was influential in both experiments. This research supports a growing literature indicating that intraspecific variability among clones of a dominant species can affect interspecific interactions and that such variability in a native species can affect performance of an invading species.

  14. Plant traits and spread of the invasive salt marsh grass, Spartina ...

    African Journals Online (AJOL)

    Spartina alterniflora Loisel., widely recognised as an aggressive invader of estuaries and salt marshes around the world, was discovered growing in the temporarily open/closed Great Brak Estuary on the southern Cape coast of South Africa in 2004. This is the first record of this invasive plant in Africa as well as its first ...

  15. Species' traits help predict small mammal responses to habitat homogenization by an invasive grass.

    Science.gov (United States)

    Ceradini, Joseph P; Chalfoun, Anna D

    2017-07-01

    Invasive plants can negatively affect native species, however, the strength, direction, and shape of responses may vary depending on the type of habitat alteration and the natural history of native species. To prioritize conservation of vulnerable species, it is therefore critical to effectively predict species' responses to invasive plants, which may be facilitated by a framework based on species' traits. We studied the population and community responses of small mammals and changes in habitat heterogeneity across a gradient of cheatgrass (Bromus tectorum) cover, a widespread invasive plant in North America. We live-trapped small mammals over two summers and assessed the effect of cheatgrass on native small mammal abundance, richness, and species-specific and trait-based occupancy, while accounting for detection probability and other key habitat elements. Abundance was only estimated for the most common species, deer mice (Peromyscus maniculatus). All species were pooled for the trait-based occupancy analysis to quantify the ability of small mammal traits (habitat association, mode of locomotion, and diet) to predict responses to cheatgrass invasion. Habitat heterogeneity decreased with cheatgrass cover. Deer mouse abundance increased marginally with cheatgrass. Species richness did not vary with cheatgrass, however, pocket mouse (Perognathus spp.) and harvest mouse (Reithrodontomys spp.) occupancy tended to decrease and increase, respectively, with cheatgrass cover, suggesting a shift in community composition. Cheatgrass had little effect on occupancy for deer mice, 13-lined ground squirrels (Spermophilus tridecemlineatus), and Ord's kangaroo rat (Dipodomys ordii). Species' responses to cheatgrass primarily corresponded with our a priori predictions based on species' traits. The probability of occupancy varied significantly with a species' habitat association but not with diet or mode of locomotion. When considered within the context of a rapid habitat change

  16. Species’ traits help predict small mammal responses to habitat homogenization by an invasive grass

    Science.gov (United States)

    Ceradini, Joseph P.; Chalfoun, Anna

    2017-01-01

    Invasive plants can negatively affect native species, however, the strength, direction, and shape of responses may vary depending on the type of habitat alteration and the natural history of native species. To prioritize conservation of vulnerable species, it is therefore critical to effectively predict species’ responses to invasive plants, which may be facilitated by a framework based on species’ traits. We studied the population and community responses of small mammals and changes in habitat heterogeneity across a gradient of cheatgrass (Bromus tectorum) cover, a widespread invasive plant in North America. We live-trapped small mammals over two summers and assessed the effect of cheatgrass on native small mammal abundance, richness, and species-specific and trait-based occupancy, while accounting for detection probability and other key habitat elements. Abundance was only estimated for the most common species, deer mice (Peromyscus maniculatus). All species were pooled for the trait-based occupancy analysis to quantify the ability of small mammal traits (habitat association, mode of locomotion, and diet) to predict responses to cheatgrass invasion. Habitat heterogeneity decreased with cheatgrass cover. Deer mouse abundance increased marginally with cheatgrass. Species richness did not vary with cheatgrass, however, pocket mouse (Perognathus spp.) and harvest mouse (Reithrodontomys spp.) occupancy tended to decrease and increase, respectively, with cheatgrass cover, suggesting a shift in community composition. Cheatgrass had little effect on occupancy for deer mice, 13-lined ground squirrels (Spermophilus tridecemlineatus), and Ord's kangaroo rat (Dipodomys ordii). Species’ responses to cheatgrass primarily corresponded with our a priori predictions based on species’ traits. The probability of occupancy varied significantly with a species’ habitat association but not with diet or mode of locomotion. When considered within the context of a rapid

  17. Simulating long-term effectiveness and efficiency of management scenarios for an invasive grass

    OpenAIRE

    Catherine S. Jarnevich; Tracy R. Holcombe; Catherine Cullinane Thomas; Leonardo Frid; Aaryn Olsson

    2015-01-01

    Resource managers are often faced with trade-offs in allocating limited resources to manage plant invasions. These decisions must often be made with uncertainty about the location of infestations, their rate of spread and effectiveness of management actions. Landscape level simulation tools such as state-and-transition simulation models (STSMs) can be used to evaluate the potential long term consequences of alternative management strategies and help identify those strategies that make efficie...

  18. Disease protection and allelopathic interactions of seed-transmitted endophytic pseudomonads of invasive reed grass (Phragmites australis)

    Science.gov (United States)

    White, James F.; Kingsley, Katheryn I; Kowalski, Kurt P.; Irizarry, Ivelisse; Micci, April; Soares, Marcos Antonio; Bergen, Marshall S.

    2018-01-01

    Background and aimsNon-native Phragmites australis (haplotype M) is an invasive grass that decreases biodiversity and produces dense stands. We hypothesized that seeds of Phragmites carry microbes that improve seedling growth, defend against pathogens and maximize capacity of seedlings to compete with other plants.MethodsWe isolated bacteria from seeds of Phragmites, then evaluated representatives for their capacities to become intracellular in root cells, and their effects on: 1.) germination rates and seedling growth, 2.) susceptibility to damping-off disease, and 3.) mortality and growth of competitor plant seedlings (dandelion (Taraxacum officionale F. H. Wigg) and curly dock (Rumex crispus L.)).ResultsTen strains (of 23 total) were identified and characterized; seven were identified as Pseudomonas spp. Strains Sandy LB4 (Pseudomonas fluorescens) and West 9 (Pseudomonas sp.) entered root meristems and became intracellular. These bacteria improved seed germination in Phragmites and increased seedling root branching in Poa annua. They increased plant growth and protected plants from damping off disease. Sandy LB4 increased mortality and reduced growth rates in seedlings of dandelion and curly dock.ConclusionsPhragmites plants associate with endophytes to increase growth and disease resistance, and release bacteria into the soil to create an environment that is favorable to their seedlings and less favorable to competitor plants.

  19. Simulated acid rain alters litter decomposition and enhances the allelopathic potential of the invasive plant Wedelia trilobata (Creeping Daisy)

    Science.gov (United States)

    Invasive species and acid rain cause global environmental problems. Limited information exists, however, concerning the effects of acid rain on the invasiveness of these plants. For example, creeping daisy, an invasive exotic allelopathic weed, has caused great damage in southern China where acid ra...

  20. Invasion of the Brazilian campo rupestre by the exotic grass Melinis minutiflora is driven by the high soil N availability and changes in the N cycle.

    Science.gov (United States)

    Ribeiro, Pâmella C D; Menendez, Esther; da Silva, Danielle L; Bonieck, Douglas; Ramírez-Bahena, Martha Helena; Resende-Stoianoff, Maria Aparecida; Peix, Alvaro; Velázquez, Encarna; Mateos, Pedro F; Scotti, Maria Rita

    2017-01-15

    The Serra do Rola Moça State Park (PESRM) in Minas Gerais State, Brazil is a preserved site representative of the campo rupestre biome over an ironstone outcrop that has a high level of plant diversity. Almost 60% of this grassy field has been invaded by the exotic molasses grass (Melinis minutiflora), which constitutes a severe threat to the biodiversity and survival of this biome, particularly due to the impacts of annual fires and inappropriate restoration interventions. Many invasive species exhibit a high demand for nitrogen (N). Hence, this work aimed to study the N cycle alterations promoted by M. minutiflora in a site of the campo rupestre, where the leguminous species Mimosa pogocephala was prevalent. The biome's soils exhibited a high natural N fertility and low C:N ratio. The main N source in this biome resulted from the biological N fixation performed by M. pogocephala associated with Burkholderia nodosa, as evidenced by the total leaf N content, leaf δ 15 N signature, nodule occupation and bacterial molecular identification analyses. The displacement of native species by molasses grass was associated with changes in the soil N forms, namely the nitrate increased as the ammonium decreased. The latter was the dominant N form in the native species plots, as observed in the soil analysis of total N, ammonium and nitrate contents. The dominant ammonium form was changed to the nitric form by the stimulation of ammonia-oxidising bacteria populations due to the invasive species. Therefore, the key mechanism behind the invasiveness of the exotic grass and the concomitant displacement of the native species may be associated with changes in the soil N chemical species. Based on this finding and on the high N-based soil fertility found in the campo rupestre N fertilisation procedures for restoration of invaded areas should be strictly avoided in this biome. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Invasive Earthworms and Forest Successional Stage Interact to Impact Plant Litter Inputs and Particulate Organic Matter Chemistry

    Science.gov (United States)

    The landscapes colonized by invasive earthworms in the eastern U.S. are often patchworks of forest stands in various stages of successional development. We established six field sites in tulip poplar dominated forests in the Smithsonian Environmental Research Center Forest (SERC), MD, that span you...

  2. DO ADDITIONAL BANDS (COASTAL, NIR-2, RED-EDGE AND YELLOW IN WORLDVIEW-2 MULTISPECTRAL IMAGERY IMPROVE DISCRIMINATION OF AN INVASIVE TUSSOCK, BUFFEL GRASS (CENCHRUS CILIARIS?

    Directory of Open Access Journals (Sweden)

    V. Marshall

    2012-07-01

    Full Text Available Our goals is to determine if Worldview-2 8-band multispectral imagery can be used to discriminate an invasive grass species namely, Buffel grass (Cenchrus ciliaris in the subtropical arid parts of central Australia and whether it offers a tangible improvement on 4-band (visible and near infra red multispectral imagery. A Worldview-2 scene was acquired for a 10*10km area just west of Alice Springs in central Australia following heavy rains of early Summer. Mixture Tuned Matched Filtering was used to classify the image. Target and background spectra were selected in the field and extracted from the image. Linear discriminate analysis (LDA was used to examine the spectral separability of each group of the target/ background spectra. The importance of the additional spectral bands on the image classification was assessed by running LDA for both 8 and 4 bands (red, green, blue and NIR. LDA did not indicate improved separability between groups when additional spectral bands were applied. Preliminary classification results indicate that Buffel grass (Cenchrus ciliaris is detected with an omission error 44%, commission error of 11.8% and overall accuracy of 59.5%. We were surprised that the additional spectral bands did not improve spectral separability and in part attribute this to the high degree of variance we observed within groups of spectra, which was particularly observable in the NIR2 and Yellow bands. The analyses may be significantly improved by acquiring imagery following the first big rains at the end of the dry season. At this time, phonological differences between our focal species and the surrounding native vegetation should be maximised. We suspect that Worldview-2 will offer even greater potential for the discrimination of Buffel grass under these conditions, being able to fully utilise the yellow-band in particular.

  3. Strong genetic differentiation in the invasive annual grass Bromus tectorum across the Mojave-Great Basin ecological transition zone

    Science.gov (United States)

    Susan E. Meyer; Elizabeth A. Leger; Desiree R. Eldon; Craig E. Coleman

    2016-01-01

    Bromus tectorum, an inbreeding annual grass, is a dominant invader in sagebrush steppe habitat in North America. It is also common in warm and salt deserts, displaying a larger environmental tolerance than most native species. We tested the hypothesis that a suite of habitat-specific B. tectorum lineages dominates warm desert habitats. We sampled 30 B....

  4. Tall Grass Invasion After Grassland Abandonment Influences the Availability of Palatable Plants for Wild Herbivores: Insight into the Conservation of the Apennine Chamois Rupicapra pyrenaica ornata.

    Science.gov (United States)

    Corazza, Marcello; Tardella, Federico Maria; Ferrari, Carlo; Catorci, Andrea

    2016-06-01

    Invasion of the tall grass Brachypodium genuense was observed in an area of the central Apennines (Italy) where the population size of Apennine chamois (Rupicapra pyrenaica ornata) was in strong decline. Since this dominant tall grass threatens biodiversity and forage quality, our hypothesis was that B. genuense abundance influenced that of palatable species for the chamois, depending on their functional traits and distribution patterns. Our sampling design used plots of 10 × 10 m and 1 × 1 m to investigate the plant community level and fine-scale interactions. We analyzed data using correlation, generalized linear models, and redundancy analyses. We found that B. genuense can reach high abundance values on the deepest soils. Its high cover value influences plant community composition by competitive exclusion of subordinate species and suppression of functional features because of temporal or spatial niche overlap. This leads to low cover of palatable species at a fine scale, and to poor pasture quality for chamois at a wider scale. Therefore, we postulated that B. genuense invasion, enhanced by long-term grazing cessation, may reduce the availability of palatable plants for Apennine chamois, especially below the potential timberline (1900-2000 m a.s.l.). The high abundance of B. genuense may amplify the effect of other negative factors, such as competition with red deer (Cervus elaphus) and climate change, in restricting the suitable habitat of the Apennine chamois to the higher sectors of the central Apennines. Thus, we suggested that B. genuense spread should be monitored carefully and plans to control its invasion should be implemented.

  5. Tall Grass Invasion After Grassland Abandonment Influences the Availability of Palatable Plants for Wild Herbivores: Insight into the Conservation of the Apennine Chamois Rupicapra pyrenaica ornata

    Science.gov (United States)

    Corazza, Marcello; Tardella, Federico Maria; Ferrari, Carlo; Catorci, Andrea

    2016-06-01

    Invasion of the tall grass Brachypodium genuense was observed in an area of the central Apennines (Italy) where the population size of Apennine chamois ( Rupicapra pyrenaica ornata) was in strong decline. Since this dominant tall grass threatens biodiversity and forage quality, our hypothesis was that B. genuense abundance influenced that of palatable species for the chamois, depending on their functional traits and distribution patterns. Our sampling design used plots of 10 × 10 m and 1 × 1 m to investigate the plant community level and fine-scale interactions. We analyzed data using correlation, generalized linear models, and redundancy analyses. We found that B. genuense can reach high abundance values on the deepest soils. Its high cover value influences plant community composition by competitive exclusion of subordinate species and suppression of functional features because of temporal or spatial niche overlap. This leads to low cover of palatable species at a fine scale, and to poor pasture quality for chamois at a wider scale. Therefore, we postulated that B. genuense invasion, enhanced by long-term grazing cessation, may reduce the availability of palatable plants for Apennine chamois, especially below the potential timberline (1900-2000 m a.s.l.). The high abundance of B. genuense may amplify the effect of other negative factors, such as competition with red deer ( Cervus elaphus) and climate change, in restricting the suitable habitat of the Apennine chamois to the higher sectors of the central Apennines. Thus, we suggested that B. genuense spread should be monitored carefully and plans to control its invasion should be implemented.

  6. Do invasive plants structure microbial communities to accelerate decomposition in intermountain grasslands?

    Science.gov (United States)

    McTee, Michael R; Lekberg, Ylva; Mummey, Dan; Rummel, Alexii; Ramsey, Philip W

    2017-12-01

    Invasive plants are often associated with greater productivity and soil nutrient availabilities, but whether invasive plants with dissimilar traits change decomposer communities and decomposition rates in consistent ways is little known. We compared decomposition rates and the fungal and bacterial communities associated with the litter of three problematic invaders in intermountain grasslands; cheatgrass ( Bromus tectorum ), spotted knapweed ( Centaurea stoebe ) and leafy spurge ( Euphorbia esula ), as well as the native bluebunch wheatgrass ( Pseudoroegneria spicata ). Shoot and root litter from each plant was placed in cheatgrass, spotted knapweed, and leafy spurge invasions as well as remnant native communities in a fully reciprocal design for 6 months to see whether decomposer communities were species-specific, and whether litter decomposed fastest when placed in a community composed of its own species (referred to hereafter as home-field advantage-HFA). Overall, litter from the two invasive forbs, spotted knapweed and leafy spurge, decomposed faster than the native and invasive grasses, regardless of the plant community of incubation. Thus, we found no evidence of HFA. T-RFLP profiles indicated that both fungal and bacterial communities differed between roots and shoots and among plant species, and that fungal communities also differed among plant community types. Synthesis . These results show that litter from three common invaders to intermountain grasslands decomposes at different rates and cultures microbial communities that are species-specific, widespread, and persistent through the dramatic shifts in plant communities associated with invasions.

  7. Evidence for recent adaptative evolution in mid-Atlantic populations of an invasive exotic grass, Microstegium vimineum, Japanese stiltgrass

    Science.gov (United States)

    The establishment and spread of invasive plants has often been associated with a ‘general-purpose genotype,’ and a corresponding high degree of phenotypic plasticity when introduced to a new environment. However, changes in evolutionary potential of invasive species need to be considered in additio...

  8. Physical stress, not biotic interactions, preclude an invasive grass from establishing in forb-dominated salt marshes.

    Directory of Open Access Journals (Sweden)

    Qiang He

    Full Text Available Biological invasions have become the focus of considerable concern and ecological research, yet the relative importance of abiotic and biotic factors in controlling the invasibility of habitats to exotic species is not well understood. Spartina species are highly invasive plants in coastal wetlands; however, studies on the factors that control the success or failure of Spartina invasions across multiple habitat types are rare and inconclusive.We examined the roles of physical stress and plant interactions in mediating the establishment of the smooth cordgrass, Spartina alterniflora, in a variety of coastal habitats in northern China. Field transplant experiments showed that cordgrass can invade mudflats and low estuarine marshes with low salinity and frequent flooding, but cannot survive in salt marshes and high estuarine marshes with hypersaline soils and infrequent flooding. The dominant native plant Suaeda salsa had neither competitive nor facilitative effects on cordgrass. A common garden experiment revealed that cordgrass performed significantly better when flooded every other day than when flooded weekly. These results suggest that physical stress rather than plant interactions limits cordgrass invasions in northern China.We conclude that Spartina invasions are likely to be constrained to tidal flats and low estuarine marshes in the Yellow River Delta. Due to harsh physical conditions, salt marshes and high estuarine marshes are unlikely to be invaded. These findings have implications for understanding Spartina invasions in northern China and on other coasts with similar biotic and abiotic environments.

  9. A field guide for selecting the most appropriate treatment in sagebrush and pinon-juniper ecosystems in the Great Basin: Evaluating resilience to disturbance and resistance to invasive annual grasses, and predicting vegetation response

    Science.gov (United States)

    Richard F. Miller; Jeanne C. Chambers; Mike Pellant

    2014-01-01

    This field guide identifies seven primary components that largely determine resilience to disturbance, as well as resistance to invasive grasses and plant succession following treatment of areas of concern. The primary components are (1) characteristics of the ecological site, (2) current vegetation prior to treatment, (3) disturbance history, (4) type, timing, and...

  10. Experimental evidence for an alkali ecotype of Lolium multiflorum, an exotic invasive annual grass in the Central Valley, CA, USA

    OpenAIRE

    Dawson, K.; Veblen, Kari E.; Young, T. P.

    2007-01-01

    One of the characteristics of highly invaded ecosystems is that invasive species are often poor invaders of edaphically severe sites, which become refuges for native flora. To investigate the invasive potential of Lolium multiflorum (Hick.) into alkali sites in California, an ex-situ reciprocal transfer experiment was carried out using seeds from populations of L. multiflorum taken from three sites differing in alkalinity (and inundation), including alkali sink soils (pH 8.5) and sink-edge so...

  11. Equilibrium and kinetic studies of copper biosorption by dead Ceriporia lacerata biomass isolated from the litter of an invasive plant in China.

    Science.gov (United States)

    Li, Xiaona; Li, Airong; Long, Mingzhong; Tian, Xingjun

    2015-01-01

    Ceriporia lacerata, a strain of white-rot fungus isolated from the litter of an invasive plant (Solidago canadensis) in China, was little known about its properties and utilization. In this work, the copper(II) biosorption characteristics of formaldehyde inactivated C. lacerata biomass were examined as a function of initial pH, initial copper(II) concentration and contact time, and the adsorptive equilibrium and kinetics were simulated, too. The optimum pH was found to be 6.0 at experimental conditions of initial copper(II) concentration 100 mg/L, biomass dose 2 g/L, contact time 12 h, shaking rate 150 r/min and temperature 25°C. Biosorption equilibrium cost about 1 hour at experimental conditions of pH 6.0, initial copper(II) concentration 100 mg/L, C. lacerata dose 2 g/L, shaking rate 150 r/min and temperature 25°C. At optimum pH 6.0, highest copper(II) biosorption amounts were 6.79 and 7.76 mg/g for initial copper(II) concentration of 100 and 200 mg/L, respectively (with other experimental parameters of C. lacerata dose 2 g/L, shaking rate 150 r/min and temperature 25°C). The pseudo second-order adsorptive model gave the best adjustment for copper(II) biosorption kinetics. The equilibrium data fitted very well to both Langmuir and Freundlich adsorptive isotherm models. Without further acid or alkali treatment for improving adsorption properties, formaldehyde inactivated C. lacerata biomass possesses good biosorption characteristics on copper(II) removal from aqueous solutions.

  12. Are Mojave Desert annual species equal? Resource acquisition and allocation for the invasive grass Bromus madritensis subsp. rubens (Poaceae) and two native species

    Science.gov (United States)

    Defalco, Lesley A.; Bryla, David R.; Smith-Longozo, Vickie; Nowak, Robert S.

    2003-01-01

    Abundance of invasive plants is often attributed to their ability ot outcompete native species. We compared resource acquisition and allocation of the invasive annual grass Bromus madritensis subsp. rubens with that of two native Mojave Desert annuals, Vulpia octoflora and Descurainia pinnata, in a glasshouse experiment. Each species was grown in monoculture at two densities and two levels of N availability to compare how these annuals capture resources and to understand their relative sensitivities to environmental change. During >4 mo of growth, Bromus used water more rapidly and had greater biomass and N content than the natives, partly because of its greater root-surface area and its exploitation of deep soils. Bromus also had greater N uptake, net assimilation and transpiration rates, and canopy area than Vulpia. Resource use by Bromuswas less sensitive to changes in N availability or density than were the natives. The two native species in this study produced numerous small seeds that tended to remain dormant, thus ensuring escape of offspring from unfavorable germination conditions; Bromus produced fewer but larger seeds that readily germinated. Collectively, these traits give Bromus the potential to rapidly establish in diverse habitats of the Mojave Desert, thereby gaining an advantage over coexisting native species.

  13. A potential conflict between preserving regional plant diversity and biotic resistance to an invasive grass, Microstegium vimineum

    Science.gov (United States)

    J. Stephen Brewer

    2010-01-01

    The relevance of diversity-biotic resistance studies to conservation of biodiversity could be improved by simultaneously examining the drivers of regional diversity and their effects on local species diversity and invasion. Using path analysis, I examined direct and indirect effects of various abiotic factors (i.e., flooding, treefall gaps, soil texture, proximity to...

  14. Using a C4 Invasive Grass to Isolate the Role of Detrital Carbon versus Rhizodeposit Carbon in Supplying Soil Carbon Pools

    Science.gov (United States)

    Sokol, N.; Bradford, M.

    2016-12-01

    Plant inputs are the primary sources of carbon (C) to soil organic carbon (SOC) pools. Historically, detrital plant sources were thought to dominate C supply to SOC pools. An emerging body of research highlights the previously underestimated role of root exudates and other rhizodeposits. However, few experimental field studies have directly tracked the relative contributions of rhizodeposits versus detritial C inputs into different SOC pools, due to how methodologically challenging they are to measure in a field setting. Here, I present the first 3 years of data from an experimental field study of the prolific, C4 invasive grass species Microstegium vimineum. I use its unique isotopic signature in plots manipulated to contain detrital-only and rhizodeposit-only inputs, to track their relative contributions into microbial biomass C, particulate organic C (POC; >53 um) and mineral-associated organic C (MIN C; emerging theory on the primacy of the belowground, root-associated pathway in supplying C to soil C pools, this increase is generally assumed to be through the MIN C pool due to 1) the lower molecular weight of rhizodeposit compounds, and 2) the close physical association between rhizodeposits and soil mineral surfaces. Our results point to an underappreciated, central role of the POM C pool as a passageway for both detrital and rhizodeposit C inputs to the soil.

  15. Litter survey in Virginia.

    Science.gov (United States)

    1976-01-01

    This report summarizes the findings of the litter survey for highways, urban areas, and recreational areas as specified in the "Virginia Litter Control Act". Litter samples from 61 highway sites, 11 urban sites, and 10 recreational sites geographical...

  16. Fungal disease prevention in seedlings of rice (Oryza sativa) and other grasses by growth-promoting seed-associated endophytic bacteria from invasive Phragmites australis

    Science.gov (United States)

    Verma, Satish K.; Kingsley, Kathryn L.; Bergen, Marshall S.; Kowalski, Kurt P.; White, James F.

    2018-01-01

    Non-cultivated plants carry microbial endophytes that may be used to enhance development and disease resistance of crop species where growth-promoting and protective microbes may have been lost. During seedling establishment, seedlings may be infected by several fungal pathogens that are seed or soil borne. Several species of Fusarium, Pythium and other water moulds cause seed rots during germination. Fusariumblights of seedlings are also very common and significantly affect seedling development. In the present study we screened nine endophytic bacteria isolated from the seeds of invasive Phragmites australis by inoculating onto rice, Bermuda grass (Cynodon dactylon), or annual bluegrass (Poa annua) seeds to evaluate plant growth promotion and protection from disease caused by Fusarium oxysporum. We found that three bacteria belonging to genus Pseudomonas spp. (SLB4-P. fluorescens, SLB6-Pseudomonas sp. and SY1-Pseudomonassp.) promoted seedling development, including enhancement of root and shoot growth, and stimulation of root hair formation. These bacteria were also found to increase phosphate solubilization in in vitro experiments. Pseudomonas sp. (SY1) significantly protected grass seedlings from Fusarium infection. In co-culture experiments, strain SY1 strongly inhibited fungal pathogens with 85.71% growth inhibition of F. oxysporum, 86.33% growth inhibition of Curvularia sp. and 82.14% growth inhibition of Alternaria sp. Seedlings previously treated with bacteria were found much less infected by F. oxysporum in comparison to non-treated controls. On microscopic observation we found that bacteria appeared to degrade fungal mycelia actively. Metabolite products of strain SY1 in agar were also found to inhibit fungal growth on nutrient media. Pseudomonas sp. (SY1) was found to produce antifungal volatiles. Polymerase chain reaction (PCR) amplification using specific primers for pyrrolnitirin synthesis and HCN (hydrogen cyanide) production

  17. Plant litter chemistry alters the content and composition of organic carbon associated with soil mineral and aggregate fractions in invaded ecosystems.

    Science.gov (United States)

    Tamura, Mioko; Suseela, Vidya; Simpson, Myrna; Powell, Brian; Tharayil, Nishanth

    2017-10-01

    Through the input of disproportionate quantities of chemically distinct litter, invasive plants may potentially influence the fate of organic matter associated with soil mineral and aggregate fractions in some of the ecosystems they invade. Although context dependent, these native ecosystems subjected to prolonged invasion by exotic plants may be instrumental in distinguishing the role of plant-microbe-mineral interactions from the broader edaphic and climatic influences on the formation of soil organic matter (SOM). We hypothesized that the soils subjected to prolonged invasion by an exotic plant that input recalcitrant litter (Japanese knotweed, Polygonum cuspidatum) would have a greater proportion of plant-derived carbon (C) in the aggregate fractions, as compared with that in adjacent soil inhabited by native vegetation that input labile litter, whereas the soils under an invader that input labile litter (kudzu, Pueraria lobata) would have a greater proportion of microbial-derived C in the silt-clay fraction, as compared with that in adjacent soils that receive recalcitrant litter. At the knotweed site, the higher C content in soils under P. cuspidatum, compared with noninvaded soils inhabited by grasses and forbs, was limited to the macroaggregate fraction, which was abundant in plant biomarkers. The noninvaded soils at this site had a higher abundance of lignins in mineral and microaggregate fractions and suberin in the macroaggregate fraction, partly because of the greater root density of the native species, which might have had an overriding influence on the chemistry of the above-ground litter input. At the kudzu site, soils under P. lobata had lower C content across all size fractions at a 0-5 cm soil depth despite receiving similar amounts of Pinus litter. Contrary to our prediction, the noninvaded soils receiving recalcitrant Pinus litter had a similar abundance of plant biomarkers across both mineral and aggregate fractions, potentially because of

  18. Decomposition of Arachis pintoi and Hyparrhenia rufa litters in monoculture and intercropped systems under lowland soil

    Directory of Open Access Journals (Sweden)

    Oliveira Christiane Abreu de

    2003-01-01

    Full Text Available Tropical grasslands under lowland soils are generally underutilized and the litter of forage legumes may be used to recover these degraded pastures. The objective of this work was to study the dynamics of litter decomposition of Arachis pintoi (pinto peanut, Hyparrhenia rufa (thatching grass and a mixture of both species in a lowland soil. These treatments were analyzed in three areas: grass monoculture, legume monoculture and legume intercropped with the grass during the dry and wet seasons. Litter bags containing the legume, grass or a mixture of both species were incubated to estimate the decomposition rate and microorganism colonization. Decomposition constants (K and litter half-lives (T1/2 were estimated by an exponential model whereas number of microorganisms in specific media were determined by plate dilution. The decomposition rate, release of nutrients and microorganisms number, especially bacteria, increased when pinto peanut was added to thatching grass, influenced by favorable lignin/N and C/N ratios in legume litter. When pinto peanut litter was incubated in the grass plots, 50% N and P was released within about 135 days in the dry season and in the wet season, the equivalent release occurred within 20 days. These results indicate that A. pintoi has a great potential for nutrient recycling via litter and can be used to recover degraded areas.

  19. Effects of tree leaf litter, deer fecal pellets, and soil properties on growth of an introduced earthworm (Lumbricus terrestris): Implications for invasion dynamics

    Science.gov (United States)

    Kassidy N. Yatso; Erik A. Lilleskov

    2016-01-01

    Invasive earthworm communities are expanding into previously earthworm-free forests of North America, producing profound ecosystem changes. Lumbricus terrestris is an invasive anecic earthworm that consumes a large portion of the detritus on the soil surface, eliminating forest floor organic horizons and reducing soil organic matter. Two mesocosm...

  20. Estoque de serapilheira e fertilidade do solo em pastagem degradada de Brachiaria decumbens após implantação de leguminosas arbustivas e arbóreas forrageiras Soil litter stock and fertility after planting leguminous shrubs and forage trees on degraded signal grass pasture

    Directory of Open Access Journals (Sweden)

    André Barbosa Silva

    2013-04-01

    secondary effects on soil fertility, such as acidification or nutrient movement from deeper to the surface soil layers. This study evaluated the soil litter stock and fertility of degraded Brachiaria decumbens pastures after planting leguminous shrubs and forage trees. For this purpose, we sampled (March 2010 degraded Brachiaria decumbens pasture planted in July 2008 in an intercropping experiment with sabiá (Mimosa caesalpiniaefolia, leucaena (Leucaena leucocephala, mororó (Bauhinia cheilantha and gliricidia (Gliricidia sepium, as well as N-fertilized and unfertilized brachiaria. Soil and litter was sampled (layers 0-10, 10-20 and 20-40 cm in three transects, at alternating points covered by grasses and by legumes, totaling seven composite samples per plot to determine soil pH, P, K , Ca, Mg, and Al and calculate sum of bases, effective cation exchange capacity and aluminum saturation. Litter was visually separated in legumes, grasses and unidentified material to quantify dry matter, organic matter, N, P, C, acid-detergent fiber, and lignin. The use of legumes increased the levels of total N in litter and reduced the C: N ratios, especially of gliricidia and sabiá, although the lignin levels in the latter were high. There was a significant effect of legume soil cover, with no differences between them, on pH and K (layer 0-10 cm and on pH, K and Al (layer 10-20 cm.

  1. Response of dominant grass and shrub species to water manipulation: an ecophysiological basis for shrub invasion in a Chihuahuan Desert grassland.

    Science.gov (United States)

    Throop, Heather L; Reichmann, Lara G; Sala, Osvaldo E; Archer, Steven R

    2012-06-01

    Increases in woody vegetation and declines in grasses in arid and semi-arid ecosystems have occurred globally since the 1800s, but the mechanisms driving this major land-cover change remain uncertain and controversial. Working in a shrub-encroached grassland in the northern Chihuahuan Desert where grasses and shrubs typically differ in leaf-level nitrogen allocation, photosynthetic pathway, and root distribution, we asked if differences in leaf-level ecophysiology could help explain shrub proliferation. We predicted that the relative performance of grasses and shrubs would vary with soil moisture due to the different morphological and physiological characteristics of the two life-forms. In a 2-year experiment with ambient, reduced, and enhanced precipitation during the monsoon season, respectively, the encroaching C(3) shrub (honey mesquite Prosopis glandulosa) consistently and substantially outperformed the historically dominant C(4) grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates while also maintaining a more favorable leaf water status. These differences persisted across a wide range of soil moisture conditions, across which mesquite photosynthesis was decoupled from leaf water status and moisture in the upper 50 cm of the soil profile. Mesquite's ability to maintain physiologically active leaves for a greater fraction of the growing season than black grama potentially amplifies and extends the importance of physiological differences. These physiological and phenological differences may help account for grass displacement by shrubs in drylands. Furthermore, the greater sensitivity of the grass to low soil moisture suggests that grasslands may be increasingly susceptible to shrub encroachment in the face of the predicted increases in drought intensity and frequency in the desert of the southwestern USA.

  2. Litter Controls Earthworm-Mediated Carbon and Nitrogen Transformations in Soil from Temperate Riparian Buffers

    OpenAIRE

    Maria Kernecker; Joann K. Whalen; Robert L. Bradley

    2014-01-01

    Nutrient cycling in riparian buffers is partly influenced by decomposition of crop, grass, and native tree species litter. Nonnative earthworms in riparian soils in southern Quebec are expected to speed the processes of litter decomposition and nitrogen (N) mineralization, increasing carbon (C) and N losses in gaseous forms or via leachate. A 5-month microcosm experiment evaluated the effect of Aporrectodea turgida on the decomposition of 3 litter types (deciduous leaves, reed canarygrass, an...

  3. Development of remote sensing indicators for mapping episodic die-off of an invasive annual grass (Bromus tectorum) from the Landsat archive

    Science.gov (United States)

    Peter J. Weisberg; Thomas E. Dilts; Owen W. Baughman; Susan E. Meyer; Elizabeth A. Leger; K. Jane Van Gunst; Lauren Cleeves

    2017-01-01

    The exotic annual grass Bromus tectorum (cheatgrass) dominates vast acreages of rangeland in the western USA, leading to increased fire frequency and ecosystem degradation that is often irreversible. Episodic regeneration failure (“die-off”) has been observed in cheatgrass monocultures and can have negative ecosystem consequences, but can also provide an opportunity...

  4. Lignin degradation during plant litter photodegradation

    Science.gov (United States)

    Lin, Y.; King, J. Y.

    2014-12-01

    Lignin is the second most abundant compound, after cellulose, synthesized by plants. Numerous studies have demonstrated that initial lignin concentration is negatively correlated with litter decomposition rate under both laboratory and field conditions. Thus lignin is commonly considered to be a "recalcitrant" compound during litter decomposition. However, lignin can also serve as a radiation-absorbing compound during photodegradation, the process through which solar radiation breaks down organic matter. Here, we synthesize recent studies concerning lignin degradation during litter photodegradation and report results from our study on how photodegradation changes lignin chemistry at a molecular scale. Recent field studies have found that litter with high initial lignin concentration does not necessarily exhibit high mass loss during photodegradation. A meta-analysis (King et al. 2012) even found a weak negative correlation between initial lignin concentration and photodegradation rate. Contradicting results have been reported with regard to the change in lignin concentration during photodegradation. Some studies have found significant loss of lignin during photodegradation, while others have not. In most studies, loss of lignin only accounts for a small proportion of the overall mass loss. Using NMR spectroscopy, we found significant loss of lignin structural units containing beta-aryl ether linkages during photodegradation of a common grass litter, Bromus diandrus, even though conventional forage fiber analysis did not reveal changes in lignin concentration. Both our NMR and fiber analyses supported the idea that photodegradation induced loss of hemicellulose, which was mainly responsible for the litter mass loss during photodegradation. Our results suggest that photodegradation induces degradation, but not necessarily complete breakdown, of lignin structures and consequently exposes hemicellulose and cellulose to microbial decomposition. We conclude that lignin

  5. Kangaroo grass

    African Journals Online (AJOL)

    STORAGESEVER

    2009-04-06

    Apr 6, 2009 ... in Australia (Hayman, 1960) and is often used as a forage species for domestic and wild animals. It is also found in some parts of Africa, Asia and the Pacific. It commonly grows in grassland and opens woodland communities. Kangaroo grass is a tufted perennial that can grow up to 1.5 m tall and 0.5 m ...

  6. Litter traits and palatability to detritivores: a case study across bio-geographical boundaries

    Directory of Open Access Journals (Sweden)

    Aline Ferreira Quadros

    Full Text Available The activity of the litter-feeding macrofauna affects litter decomposition rates at the local scale, and their preference for particular litter types is mediated by litter traits. Environmental changes such as invasion by exotic plants may change the characteristics of the litter at a local scale, with consequences to ecosystem processes. Here we evaluated the feeding preferences of four detritivores (terrestrial isopods from two biogeographic regions (neotropical and palearctic, offering them native or non-native litter in cafeteria experiments. Our results show that isopods from different geographical regions exhibit essentially the same food preference, irrespective of whether or not they previously had encountered the litter tested. Combining the isopods' preference ranks with the principal component analysis of nine litter traits, we show that preference increases with increasing nitrogen and calcium contents and decreases with increasing toughness, C:N ratio and thickness, irrespective of the geographical origin of both litter and detritivores. We conclude that the palatability of a non-native litter to the native detritivore community can be predicted from their respective litter traits and thus, native detritivores will feed on a particular non-native litter type as likely as do detritivores in the native range of the plant. As the combination of traits that indicates palatability to the isopods also indicates litter decomposability, it could be possible to predict ecosystem responses in terms of litter decomposition rates upon changes in litter composition.

  7. Marine Anthropogenic Litter

    OpenAIRE

    Bergmann, Melanie; Gutow, Lars; Klages, Michael

    2015-01-01

    This book describes how manmade litter, primarily plastic, has spread into the remotest parts of the oceans and covers all aspects of this pollution problem from the impacts on wildlife and human health to socio-economic and political issues. Marine litter is a prime threat to marine wildlife, habitats and food webs worldwide. The book illustrates how advanced technologies from deep-sea research, microbiology and mathematic modelling as well as classic beach litter counts by volunteers co...

  8. Grass Lignocellulose

    Science.gov (United States)

    Akin, Danny E.

    Grass lignocelluloses are limited in bioconversion by aromatic constituents, which include both lignins and phenolic acids esters. Histochemistry, ultraviolet absorption microspectrophotometry, and response to microorganisms and specific enzymes have been used to determine the significance of aromatics toward recalcitrance. Coniferyl lignin appears to be the most effective limitation to biodegradation, existing in xylem cells of vascular tissues; cell walls with syringyl lignin, for example, leaf sclerenchyma, are less recalcitrant. Esterified phenolic acids, i.e., ferulic and p-coumaric acids, often constitute a major chemical limitation in nonlignified cell walls to biodegradation in grasses, especially warm-season species. Methods to improve biodegradability through modification of aromatics include: plant breeding, use of lignin-degrading white-rot fungi, and addition of esterases. Plant breeding for new cultivars has been especially effective for nutritionally improved forages, for example, bermudagrasses. In laboratory studies, selective white-rot fungi that lack cellulases delignified the lignocellulosic materials and improved fermentation of residual carbohydrates. Phenolic acid esterases released p-coumaric and ferulic acids for potential coproducts, improved the available sugars for fermentation, and improved biodegradation. The separation and removal of the aromatic components for coproducts, while enhancing the availability of sugars for bioconversion, could improve the economics of bioconversion.

  9. Impact of invasion by molasses grass (Melinis minutifloraP. Beauv. on native species and on fires in areas of campo-cerrado in Brazil

    Directory of Open Access Journals (Sweden)

    Rafael Drumond Rossi

    2014-12-01

    Full Text Available In the Cerrado Biome of Brazil, African grasses constitute a serious problem, occurring in virtually all protected areas. Molasses grass (Melinis minutiflora P. Beauv. accumulates more biomass than do most other species of the herbaceous stratum vegetation native to the Cerrado. In this study, our aim was to determine the impact of M. minutiflora on native vegetation, as well as (using simulations of fire traits on the characteristics of fires, in invaded areas of the Serra do Rola-Moça State Park (Parque Estadual da Serra do Rola-Moça, PESRM, a protected area where fires are frequent, in the state of Minas Gerais, Brazil. Our main results are that M. minutiflora considerably increases the amount of biomass, becoming the main combustible plant in the campo-cerrado (grassy-woody savanna fires in the PESRM; that the native monocot biomass is inversely correlated with the M. minutiflora biomass, suggesting suppression of the native herbaceous stratum; that eudicots are diminished by M. minutiflora, both in number of individuals and number of species; and that fires are more severe in M. minutiflora-invaded areas.

  10. Differences in leaf litter, ascospore production and infection of pear scab (Venturia pirina) in Dutch organic orchards

    NARCIS (Netherlands)

    Timmermans, B.G.H.; Jansonius, P.J.

    2012-01-01

    In 2010 and 2011 the amounts of leaf litter and ascospore production per unit of leaf litter area in 7 organic pear orchards throughout the Netherlands were measured. In one of the orchards, adapted managements strategies were implemented, being grass/clover that is grown as ground cover on the

  11. Effects of litters with different concentrations of phenolics on the competition between Calluna vulgaris and Deschampsia flexuosa

    NARCIS (Netherlands)

    Hofland-Zijlstra, J.D.; Berendse, F.

    2010-01-01

    We hypothesized that the outcome of competition between ericaceous plants and grasses is strongly affected by the concentrations of phenolics in the litter that they produce. To test the effect of phenolic-rich litter on soluble soil nitrogen concentrations, plant nitrogen uptake and inter-specific

  12. The influence of litter quality and micro-habitat on litter decomposition and soil properties in a silvopasture system

    Science.gov (United States)

    Tripathi, G.; Deora, R.; Singh, G.

    2013-07-01

    Studies to understand litter processes and soil properties are useful for maintaining pastureland productivity as animal husbandry is the dominant occupation in the hot arid region. We aimed to quantify how micro-habitats and combinations of litters of the introduced leguminous tree Colophospermum mopane with the grasses Cenchrus ciliaris or Lasiurus sindicus influence decomposition rate and soil nutrient changes in a hot desert silvopasture system. Litter bags with tree litter alone (T), tree + C. ciliaris in 1:1 ratio (TCC) and tree + L. sindicus 1:1 ratio (TLS) litter were placed inside and outside of the C. mopane canopy and at the surface, 3-7 cm and 8-12 cm soil depths. We examined litter loss, soil fauna abundance, organic carbon (SOC), total (TN), ammonium (NH4-N) and nitrate (NO3-N) nitrogen, phosphorus (PO4-P), soil respiration (SR) and dehydrogenase activity (DHA) in soil adjacent to each litter bag. After 12 months exposure, the mean residual litter was 40.2% of the initial value and annual decomposition rate constant (k) was 0.98 (0.49-1.80). Highest (p < 0.01) litter loss was in the first four months, when faunal abundance, SR, DHA and humidity were highest but it decreased with time. These variables and k were highest under the tree canopies. The litter loss and k were highest (p < 0.01) in TLS under the tree canopy, but the reverse trend was found for litter outside the canopy. Faunal abundance, litter loss, k, nutrient release and biochemical activities were highest (p < 0.01) in the 3-7 cm soil layer. Positive correlations of litter loss and soil fauna abundance with soil nutrients, SR and DHA demonstrated the interactions of litter quality and micro-habitats together with soil fauna on increased soil fertility. These results suggest that a Colophospermum mopane and L. sindicus silvopasture system best promotes faunal abundance, litter decomposition and soil fertility. The properties of these species and the associated faunal resources may be

  13. Litter materials and the incidence of carcass lesions in broilers chickens

    Directory of Open Access Journals (Sweden)

    RG Garcia

    2012-03-01

    Full Text Available The aim of this study was to evaluate the effects of different litter materials on litter compaction, broiler feathering and the incidence of carcass lesions. In the experiment, 3240 one-day-old Ross® chicks were selected by sex and distributed according to a completely randomized experimental design in a 2 x 6 factorial arrangement (two sex and six litter materials. The following litter materials were used: wood shavings, rice husks, chopped Napier grass, 50% sugar cane bagasse plus 50% wood shavings, 50% sugar cane bagasse plus 50% rice husks, and pure sugar cane bagasse. Litter compaction was weekly assessed using a penetrometer. On days 21, 35 and 42 of the experimental period, feathering on the back and legs was scored according to a 0 - 10 scale. On day 42, birds were slaughtered and the presence of bruises, scratches and footpad lesions was recorded. Litter material had no effect on bird feathering. Carcass lesions (scratches, bruises and footpad lesions were influenced by the litter material evaluated. Birds reared on sugarcane bagasse and chopped Napier grass presented more scratches, bruises and footpad lesions than the others. Dermatitis was more evident in birds reared on sugarcane bagasse, chopped Napier grass and the combination of litter materials. It was found that males presented higher incidence of dermatitis and footpad lesions than females. Each litter material presented different compaction degrees, which increased along the experimental period. Sugarcane bagasse, chopped Napier grass and the combination of bedding materials presented the highest degree of compaction, compared with wood shavings and rice husks.

  14. Weaning and separation stress: maternal motivation decreases with litter age and litter size in farmed mink

    DEFF Research Database (Denmark)

    Malmkvist, Jens; Sørensen, Dennis Dam; Larsen, Torben

    2016-01-01

    and maternal motivation around the time of weaning and separation. Therefore, we investigated effects of separating the dam from the litter using brown first-parity farm mink dams (n = 374) taken away from the litter either day 49 ± 1 (7w, n = 185) or day 56 ± 1 (8w, n = 189) after birth. The aim...... was to investigate whether the dams experienced stress/had a different motivation to be reunited with the litter after7 and 8 weeks, estimated by non-invasive determination of cortisol (FCM: Faecal Cortisol Metabolites)and dam behaviour including calls the first week after separation (D0: Day of removal, D1: next.......024). We interpret these results as a higher maternal motivation in dams at 7 weeks than at 8 weeks after birth. Additionally, the separation-induced calling in dams decreased with increasing litter size (P = 0.022). Thus in addition to litter age, the size of the litter is important for the maternal...

  15. The carbon fertilization effect over a century of anthropogenic CO2emissions: higher intracellular CO2and more drought resistance among invasive and native grass species contrasts with increased water use efficiency for woody plants in the US Southwest.

    Science.gov (United States)

    Drake, Brandon L; Hanson, David T; Lowrey, Timothy K; Sharp, Zachary D

    2017-02-01

    From 1890 to 2015, anthropogenic carbon dioxide emissions have increased atmospheric CO 2 concentrations from 270 to 400 mol mol -1 . The effect of increased carbon emissions on plant growth and reproduction has been the subject of study of free-air CO 2 enrichment (FACE) experiments. These experiments have found (i) an increase in internal CO 2 partial pressure (c i ) alongside acclimation of photosynthetic capacity, (ii) variable decreases in stomatal conductance, and (iii) that increases in yield do not increase commensurate with CO 2 concentrations. Our data set, which includes a 115-year-long selection of grasses collected in New Mexico since 1892, is consistent with an increased c i as a response to historical CO 2 increase in the atmosphere, with invasive species showing the largest increase. Comparison with Palmer Drought Sensitivity Index (PDSI) for New Mexico indicates a moderate correlation with Δ 13 C (r 2  = 0.32, P environments (Pinus longaeva and Pinus edulis in the US Southwest) as well as from wetter environments (Bromus and Poa grasses in New Mexico) suggests differing responses based on environment; arid environments in New Mexico see increased intrinsic water use efficiency (WUE) in response to historic elevated CO 2 while wetter environments see increased c i . This study suggests that (i) the observed increases in c i in FACE experiments are consistent with historical CO 2 increases and (ii) the CO 2 increase influences plant sensitivity to water shortage, through either increased WUE or c i in arid and wet environments, respectively. © 2016 John Wiley & Sons Ltd.

  16. Environmentally friendly animal litter

    Energy Technology Data Exchange (ETDEWEB)

    Chett, Boxley; McKelvie, Jessica

    2013-08-20

    A method of making an animal litter that includes geopolymerized ash, wherein, the animal litter is made from a quantity of a pozzolanic ash mixed with a sufficient quantity of water and an alkaline activator to initiate a geopolymerization reaction that forms geopolymerized ash. After the geopolymerized ash is formed, it is dried, broken into particulates, and sieved to a desired size. These geopolymerized ash particulates are used to make a non-clumping or clumping animal litter. Odor control may be accomplished with the addition of a urease inhibitor, pH buffer, an odor eliminating agent, and/or fragrance.

  17. Littering Behavior in Public Places

    Science.gov (United States)

    Robinson, Stuart N.

    1976-01-01

    This review summarizes the present state of knowledge concerning littering behavior. Available studies are categorized according to the variables that influence littering--individual and environmental. Theoretical issues of attitude-behavior consistency and incentive effectiveness are analyzed with respect to littering and litter control. Results…

  18. The impacts of Phalaris arundinacea (reed canary grass) invasion on wetland plant richness in the Oregon Coast Range, USA, depend on beavers

    Science.gov (United States)

    Perkins, T.; Wilson, M.

    2005-01-01

    Invasive plants can threaten diversity and ecosystem function. We examined the relationship between the invasive Phalaris arundinacea (reed canarygrass) and species richness in beaver wetlands in Oregon, USA. Four basins (drainages) were chosen and three sites each of beaver impoundments, unimpounded areas and areas upstream of debris jams were randomly chosen in each basin for further study (n = 36). Analysis of covariance (ANCOVA) showed that the relationship between Phalaris and species richness differed significantly (p = 0.01) by site type. Dam sites (beaver impoundments) exhibited a strong inverse relationship between Phalaris and species richness (bD = a??0.15), with one species lost for each 7% increase in Phalaris cover. In contrast, there was essentially no relationship between Phalaris cover and species richness in jam sites (debris jam impoundments formed by flooding; bJ = +0.01) and unimpounded sites (bU = a??0.03). The cycle of beaver impoundment and abandonment both disrupts the native community and provides an ideal environment for Phalaris, which once established tends to exclude development of herbaceous communities and limits species richness. Because beaver wetlands are a dominant wetland type in the Coast Range, Phalaris invasion presents a real threat to landscape heterogeneity and ecosystem function in the region.

  19. Litter Controls Earthworm-Mediated Carbon and Nitrogen Transformations in Soil from Temperate Riparian Buffers

    Directory of Open Access Journals (Sweden)

    Maria Kernecker

    2014-01-01

    Full Text Available Nutrient cycling in riparian buffers is partly influenced by decomposition of crop, grass, and native tree species litter. Nonnative earthworms in riparian soils in southern Quebec are expected to speed the processes of litter decomposition and nitrogen (N mineralization, increasing carbon (C and N losses in gaseous forms or via leachate. A 5-month microcosm experiment evaluated the effect of Aporrectodea turgida on the decomposition of 3 litter types (deciduous leaves, reed canarygrass, and soybean stem residue. Earthworms increased CO2 and N2O losses from microcosms with soybean residue, by 112% and 670%, respectively, but reduced CO2 and N2O fluxes from microcosms with reed canarygrass by 120% and 220%, respectively. Litter type controlled the CO2 flux (soybean ≥ deciduous-mix litter = reed canarygrass > no litter and the N2O flux (soybean ≥ no litter ≥ reed canarygrass > deciduous-mix litter. However, in the presence of earthworms, there was a slight increase in C and N gaseous losses of C and N relative to their losses via leachate, across litter treatments. We conclude that litter type determines the earthworm-mediated decomposition effect, highlighting the importance of vegetation management in controlling C and N losses from riparian buffers to the environment.

  20. Seasonal variation of soluble carbohydrates and starch in Echinolaena inflexa, a native grass species from the Brazilian savanna, and in the invasive grass Melinis minutiflora Variações sazonais de carboidratos solúveis e amido em Echinolaena inflexa, uma espécie nativa do cerrado, e na gramínea invasora Melinis minutiflora

    Directory of Open Access Journals (Sweden)

    A. Souza

    2010-05-01

    Full Text Available Echinolaena inflexa (Poir. Chase is an abundant C3 grass species with high biomass production in the Brazilian savanna (cerrado; Melinis minutiflora Beauv. is an African C4 forage grass widespread in cerrado and probably displacing some native herbaceous species. In the present work, we analysed seasonally the content and composition of soluble carbohydrates, the starch amounts and the above-ground biomass (phytomass of E. inflexa and M. minutiflora plants harvested in two transects at 5 and 130 m from the border in a restrict area of cerrado at the Biological Reserve and Experimental Station of Mogi-Guaçu (SP, Brazil. Results showed that water soluble carbohydrates and starch amounts from the shoots of both species varied according to the time of the year, whilst in the underground organs, variations were observed mainly in relation to the transects. Marked differences in the pattern of the above-ground biomass production between these two grasses relative to their location in the Reserve were also observed, with two peaks of the invasive species (July and January at the Reserve border. The differences in carbohydrate accumulation, partitioning and composition of individual sugars concerning time of the year and location in the Reserve were more related to the annual growth cycle of both grasses and possibly to specific physiological responses of M. minutiflora to disturbed environments in the Reserve border.Echinolaena inflexa (Poir. Chase é uma gramínea C3 muito abundante em áreas de cerrado e com alta produção de biomassa. Melinis minutiflora Beauv. é uma gramínea C4 de origem africana introduzida no Brasil para fins forrageiros, que se espalhou amplamente por áreas de cerrado, provavelmente deslocando espécies nativas. No presente trabalho, o conteúdo e a composição de carboidratos solúveis, o teor de amido e a biomassa aérea foram analisados sazonalmente em plantas de E. inflexa e M. minutiflora coletadas em dois transectos

  1. Impact of the invader Ipomoea hildebrandtii on grass biomass ...

    African Journals Online (AJOL)

    The invasive coloniser Ipomoea hildebrandtii aggravates the problem of inadequate grass forage in Kajiado district, Kenya. To test its impact on grass biomass, nitrogen (N) mineralisation and seedling establishment, grazing and coloniser density were controlled using experimental exclosures and weeding treatments ...

  2. Reciprocal effects of litter from exotic and congeneric native plant species via soil nutrients

    NARCIS (Netherlands)

    Meisner, A.; De Boer, W.; Cornelissen, J.H.C.; Van der Putten, W.H.

    2012-01-01

    Invasive exotic plant species are often expected to benefit exclusively from legacy effects of their litter inputs on soil processes and nutrient availability. However, there are relatively few experimental tests determining how litter of exotic plants affects their own growth conditions compared to

  3. From litter decomposition to soil organic matter formation: using leaf traits to predict dissolved organic carbon leaching

    Science.gov (United States)

    Soong, Jennifer; Parton, William; Calderon, Francisco; Guilbert, Kathleen; Campbell, Nell; Cotrufo, M. Francesca

    2014-05-01

    New evidence suggests that leaching of dissolved organic carbon (DOC) during litter decomposition is a major process by which decomposing litter forms stabilized soil organic matter (Cotrufo et al. 2013). Understanding this DOC flux based on plant leaf litter traits would strengthen our ability to predict ecosystem carbon (C) cycling across different vegetation types. In this study we aim to quantify the proportional relationship between CO2 and DOC partitioning during decomposition of fresh leaf litter from five different plant species, alfalfa, ash, bluestem grass, oak and pine, ranging in structural and chemical composition. The results from this laboratory incubation show a clear relationship between the lignin to cellulose ratios of litter and DOC to CO2 partitioning during four distinct phases of litter decomposition. For example, bluestem grass litter with a low lignin to cellulose ratio loses almost 50% of its C as DOC whereas pine needles with a high lignin to cellulose ratio loses much less C as DOC, indicating a potential ligno-cellulose complexation effect on carbon use efficiency and CO2 vs. DOC fluxes during litter decomposition. DOC production also decreases with time during decomposition, correlating with increasing lignin to cellulose ratios and decreasing availability of soluble, non-structural, leaf compounds (based on FTIR analysis). Initial DOC leaching can be predicted based on the amount of labile fraction in each litter type. Field data using stable isotope labeled bluestem grass show that while 18% of the surface litter C lost in 18 months of decomposition enters the soil, over 50% of litter derived C in the soil is recovered in mineral associated heavy SOM fractions, not as litter fragments in the light fraction, confirming the relative importance of the DOC flux of C from the litter layer to the soil for soil organic matter formation. These results are being used to parameterize a new litter decomposition sub-model to more accurately

  4. The Experimental Control of Littering

    Science.gov (United States)

    Clark, Roger N.; And Others

    1972-01-01

    Behavior, incentives, and education programs were researched as factors relating to littering. Experiments in theaters, forest campgrounds, and hiking and dispersed car camping areas indicate incentive systems are necessary and feasible for curbing litter problems. (BL)

  5. Large litter sizes

    DEFF Research Database (Denmark)

    Sandøe, Peter; Rutherford, K.M.D.; Berg, Peer

    2012-01-01

    This paper presents some key results and conclusions from a review (Rutherford et al. 2011) undertaken regarding the ethical and welfare implications of breeding for large litter size in the domestic pig and about different ways of dealing with these implications. Focus is primarily on the direct...... adverse consequences for animal welfare of Danish breeding for large litter sizes due to increased piglet mortality and the subsequent attempts to reverse these consequences by breeding for number of live piglets at day five rather than number of piglets born. By this change of breeding goal it seems...

  6. Resource Utilization by Native and Invasive Earthworms and Their Effects on Soil Carbon and Nitrogen Dynamics in Puerto Rican Soils

    Directory of Open Access Journals (Sweden)

    Ching-Yu Huang

    2016-11-01

    Full Text Available Resource utilization by earthworms affects soil C and N dynamics and further colonization of invasive earthworms. By applying 13C-labeled Tabebuia heterophylla leaves and 15N-labeled Andropogon glomeratus grass, we investigated resource utilization by three earthworm species (invasive endogeic Pontoscolex corethrurus, native anecic Estherella sp, and native endogeic Onychochaeta borincana and their effects on soil C and N dynamics in Puerto Rican soils in a 22-day laboratory experiment. Changes of 13C/C and 15N/N in soils, earthworms, and microbial populations were analyzed to evaluate resource utilization by earthworms and their influences on C and N dynamics. Estherella spp. utilized the 13C-labeled litter; however, its utilization on the 13C-labeled litter reduced when cultivated with P. corethrurus and O. borincana. Both P. corethrurus and O. borincana utilized the 13C-labeled litter and 15C-labeled grass roots and root exudates. Pontoscolex corethrurus facilitated soil respiration by stimulating 13C-labeled microbial activity; however, this effect was suppressed possibly due to the changes in the microbial activities or community when coexisting with O. borincana. Increased soil N mineralization by individual Estherella spp. and O. borincana was reduced in the mixed-species treatments. The rapid population growth of P. corethrurus may increase competition pressure on food resources on the local earthworm community. The relevance of resource availability to the population growth of P. corethrurus and its significance as an invasive species is a topic in need of future research.

  7. The superior re-sprouting performance of exotic grass species under different environmental conditions

    NARCIS (Netherlands)

    Caramaschi, Giovanna M.C.L.; Moribe Barbosa, Eduardo; Silva, da Dulce A.; Braga, Violeta B.; Borghetti, Fabian

    2016-01-01

    The invasive success of exotic grass species has been linked to a better physiological performance under a variety of environmental conditions. Several studies showed that disturbances such as fire and herbivory might favor invasions by exotic grasses in detrimental of native species. However,

  8. Grass production and decomposition in Southern Guinea savanna, Nigeria.

    Science.gov (United States)

    Ohiagu, C E; Wood, T G

    1979-01-01

    Annual grass production in ungrazed plots was 2,731 kg ha -1 , litter production was 1,619 kg ha -1 and decomposition was 1,789 kg ha -1 . In grazed plots the corresponding figures were 3,157 kg ha -1 , 1,440 kg ha -1 , and 1,475 kg ha -1 respectively; cattle consumed 1,405 kg ha -1 . Litter disappearance was greatest in the dry season: 1,226 kg ha -1 (69% of the annual total) disappearing in the 4 months of December to March in the ungrazed plots, largely due to consumption (790 kg ha -1 in December to March) by fungus-growing termites (Macrotermitinae). A positive linear relationship was found between maximum grass biomass and annual rainfall in West Africa.

  9. Phosphorus transformation in poultry litter and litter-treated Oxisol of Brazil assessed by 31P-NMR and wet chemical fractionation

    Directory of Open Access Journals (Sweden)

    César Roriz de Souza

    2012-11-01

    Full Text Available Large quantities of poultry litter are being produced in Brazil, which contain appreciable amounts of phosphorus (P that could be of environmental concern. To assess the immediate environmental threat, five poultry litters composed of diverse bedding material were incubated for 43 days under greenhouse conditions. The litters consisted of: coffee bean husk (CH; wood chips (WC; rice husk (RH; ground corn cobs (CC and ground napier grass (NG (Pennisetum purpureum Schum., in which the change in forms of soluble P was evaluated using 31P NMR spectroscopy. On average, 80.2 and 19.8 % of the total P in the extract, respectively, accounted for the inorganic and organic forms before incubation and 48 % of the organic P was mineralized to inorganic P in 43 days of incubation. Wide variation in the organic P mineralization rate (from 82 % -WC to 4 % - NG was observed among litters. Inorganic orthophosphate (99.9 % and pyrophosphate (0.1 % were the only inorganic P forms, whereas the organic P forms orthophosphate monoesters (76.3 % and diester (23.7 % were detected. Diester P compounds were mineralized almost completely in all litters, except in the CH litter, within the incubation period. Pyrophosphates contributed with less than 0.5% and remained unaltered during the incubation period. Wood-chip litter had a higher organic P (40 % content and a higher diester: monoester ratio; it was therefore mineralized rapidly, within the first 15 days, achieving steady state by the 29th day. Distinct mineralization patterns were observed in the litter when incubated with a clayey Oxisol. The substantial decrease observed in the organic P fraction (Po of the litter types followed the order: CH (45 % > CC (25 % > RH (13 % ≈ NG (12 % > WC (5 %, whereas the Pi fraction increased. Incubation of RH litter in soil slowed down the mineralization of organic P.

  10. Litter Inputs and Soil Aggregation in Midwestern Biofuel Crops

    Science.gov (United States)

    Kantola, I. B.; Masters, M. D.; Smyth, E. M.; DeLucia, E. H.

    2014-12-01

    Perennial C4 grasses represent alternatives to corn for the production of ethanol because of low management costs and high biomass production. To evaluate the effects of perennial grasses on the agricultural soils of the Midwest, native switchgrass and a sterile hybrid of the Asian grass Miscanthus were planted at the University of Illinois Energy Farm in 2008. Through five years of growth, above and belowground plant biomass, litter, and soil were compared with soils in plots growing a corn-corn-soy rotation typical of the area. Above- and belowground plant biomass in Miscanthus and switchgrass averaged higher than corn/soy following two years of perennial establishment, with belowground biomass exceeding corn/soy by approximately 5-fold in the year after establishment (2010) and 25-fold by 2012. Measurements of root distribution and turnover rates indicate that roots are the primary contribution of new carbon to soils under perennial crops. Physical fractionation of the soils into water stable aggregates showed 4-14% increases in macroaggregate fractions under perennial crops; the large aggregates are adhered together by organic material and indicative of the increased presence of labile carbon forms like plant roots, fungi, and plant and microbial exudates. Carbon and nitrogen analyses of the fractions show that while overall carbon has not increased significantly in whole soil, soils under perennial grasses are concentrating carbon by 5-17% in the macroaggregates after just 5 years. Native switchgrass roots (buried) and litter (surface-applied) decompose faster than Miscanthus roots and litter, but slower than corn roots and litter buried to simulate incorporation by tillage. Switchgrass soil shows the highest degree of macroaggregate formation, pointing to a high rate of litter and root decomposition and incorporation into soil structure. While macroaggregates are relatively labile soil structures compared to microaggregates and free silt and clay, they offer

  11. Quantifying the effect of plant growth on litter decomposition using a novel, triple-isotope label approach

    Science.gov (United States)

    Ernakovich, J. G.; Baldock, J.; Carter, T.; Davis, R. A.; Kalbitz, K.; Sanderman, J.; Farrell, M.

    2017-12-01

    Microbial degradation of plant detritus is now accepted as a major stabilizing process of organic matter in soils. Most of our understanding of the dynamics of decomposition come from laboratory litter decay studies in the absence of plants, despite the fact that litter decays in the presence of plants in many native and managed systems. There is growing evidence that living plants significantly impact the degradation and stabilization of litter carbon (C) due to changes in the chemical and physical nature of soils in the rhizosphere. For example, mechanistic studies have observed stimulatory effects of root exudates on litter decomposition, and greenhouse studies have shown that living plants accelerate detrital decay. Despite this, we lack a quantitative understanding of the contribution of living plants to litter decomposition and how interactions of these two sources of C build soil organic matter (SOM). We used a novel triple-isotope approach to determine the effect of living plants on litter decomposition and C cycling. In the first stage of the experiment, we grew a temperate grass commonly used for forage, Poa labillardieri, in a continuously-labelled atmosphere of 14CO2 fertilized with K15NO3, such that the grass biomass was uniformly labelled with 14C and 15N. In the second stage, we constructed litter decomposition mescososms with and without a living plant to test for the effect of a growing plant on litter decomposition. The 14C/15N litter was decomposed in a sandy clay loam while a temperate forage grass, Lolium perenne, grew in an atmosphere of enriched 13CO2. The fate of the litter-14C/15N and plant-13C was traced into soil mineral fractions and dissolved organic matter (DOM) over the course of nine weeks using four destructive harvests of the mesocosms. Our preliminary results suggest that living plants play a major role in the degradation of plant litter, as litter decomposition was greater, both in rate and absolute amount, for soil mesocosms

  12. Reciprocal effects of litter from exotic and congeneric native plant species via soil nutrients.

    Directory of Open Access Journals (Sweden)

    Annelein Meisner

    Full Text Available Invasive exotic plant species are often expected to benefit exclusively from legacy effects of their litter inputs on soil processes and nutrient availability. However, there are relatively few experimental tests determining how litter of exotic plants affects their own growth conditions compared to congeneric native plant species. Here, we test how the legacy of litter from three exotic plant species affects their own performance in comparison to their congeneric natives that co-occur in the invaded habitat. We also analyzed litter effects on soil processes. In all three comparisons, soil with litter from exotic plant species had the highest respiration rates. In two out of the three exotic-native species comparisons, soil with litter from exotic plant species had higher inorganic nitrogen concentrations than their native congener, which was likely due to higher initial litter quality of the exotics. When litter from an exotic plant species had a positive effect on itself, it also had a positive effect on its native congener. We conclude that exotic plant species develop a legacy effect in soil from the invaded range through their litter inputs. This litter legacy effect results in altered soil processes that can promote both the exotic plant species and their native congener.

  13. Sonoran Desert ecosystem transformation by a C4 grass without the grass/fire cycle

    Science.gov (United States)

    Olsson, Aaryn D.; Betancourt, Julio; McClaran, Mitchel P.; Marsh, Stuart E.

    2012-01-01

    Aim Biological invasions facilitate ecosystem transformation by altering the structure and function, diversity, dominance and disturbance regimes. A classic case is the grass–fire cycle in which grass invasion increases the frequency, scale and/or intensity of wildfires and promotes the continued invasion of invasive grasses. Despite wide acceptance of the grass–fire cycle, questions linger about the relative roles that interspecific plant competition and fire play in ecosystem transformations. Location Sonoran Desert Arizona Upland of the Santa Catalina Mountains, Arizona, USA. Methods We measured species cover, density and saguaro (Carnegiea gigantea) size structure along gradients of Pennisetum ciliare invasion at 10 unburned/ungrazed P. ciliare patches. Regression models quantified differences in diversity, cover and density with respect to P. ciliare cover, and residence time and a Fisher's exact test detected demographic changes in saguaro populations. Because P. ciliare may have initially invaded locations that were both more invasible and less diverse, we ran analyses with and without the plots in which initial infestations were located. Results Richness and diversity decreased with P. ciliare cover as did cover and density of most dominant species. Richness and diversity declined with increasing time since invasion, suggesting an ongoing transformation. The proportion of old-to-young Carnegiea gigantea was significantly lower in plots with dominant P. ciliare cover. Main conclusions Rich desert scrub (15–25 species per plot) was transformed into depauperate grassland (2–5 species per plot) within 20 years following P. ciliare invasion without changes to the fire regime. While the onset of a grass–fire cycle may drive ecosystem change in the later stages and larger scales of grass invasions of arid lands, competition by P. ciliare can drive small-scale transformations earlier in the invasion. Linking competition-induced transformation rates with

  14. Reducing Children's Littering on a Nature Trail

    Science.gov (United States)

    LaHart, David E.; Bailey, Jon S.

    1975-01-01

    This study compared incentives and educational methods to motivate children to pick up litter and to prevent littering. Incentives did aid in getting litter picked up. One-sentence anti-litter statements, educational materials, and lectures reduced littering, but incentives did not. (MR)

  15. Photodegradation of Leaf Litter in Water-Limited Ecosystems

    Science.gov (United States)

    Cory, R. M.; Powers, H.; McDowell, N.; Rahn, T.

    2008-12-01

    The longstanding view of terrestrial decomposition holds that heterotrophic respiration drives release of CO2, but recent studies, such as Austin and Vivanco (2006) have shown that in water-limited environments, photochemical decomposition of leaf litter may be equally or more effective than microbial decomposition. Although initial studies have concluded that photochemical degradation can be important in some environments, it has been difficult to quantify and the oxidative mechanisms involved remain unknown. Thus, the objectives of our study were to (1) quantify the CO2 emitted during photochemical degradation of leaf litter and (2) use the stable isotopic signatures of evolved CO2 to elucidate pathways of production. Emitted CO2 and its isotopic signature were measured using a tunable diode laser (TDL) to assess the pool of photochemically-labile plant matter (δ13C-CO2) in a given sample and to assess the source of the oxygen (δ18O-CO2). We quantified the photochemical release of CO2 and its isotopic signature from dried leaf litter of 10 tree and grass species prevalent in major biotic zones of New Mexico. The cumulative CO2 released upon exposure of 0.1-0.3 g of dried leaf litter to three hours of simulated sunlight ranged from 8-25 mg CO2-C g-1 dried litter, corresponding to 1-2% mass loss. Generally, the δ13C-CO2 was more depleted (4-7 ± 2 per mil) than the average δ13C of the respective leaf litter sample. The δ18O-CO2 evolved is approximately equal to δ18O of atmospheric O2, suggesting that the oxidation mechanism involves direct reaction with atmospheric O2.

  16. The Effects of Litter on Littering Behavior in a Forest Environment

    Science.gov (United States)

    Crump, S. Larry; And Others

    1977-01-01

    The effects of littered and nonlittered areas on littering behavior were determined in picnic areas in the Uinta National Forest, Utah. Littered and nonlittered conditions were controlled by spreading or removing litter from specified areas. Observations revealed that in the nonlittered areas there was more litter than in the littered areas. (CS)

  17. Afforestation of degraded grass land

    Energy Technology Data Exchange (ETDEWEB)

    Basappa, B.

    1983-01-01

    The suitability of 11 species was tested for planting on degraded land at Kogilemane in Belur Taluk, Karnataka. The soil was alkaline with no humus, litter or topsoil. The original vegetation was grass with the stemless palm Phoenix acaulis, still present at 600 plants per acre. Seedlings 4-6 months old and raised in polythene bags were planted in pits in July 1981; Bambusa vulgaris was planted as 8-month-old cuttings. No fertilizer was applied. The most successful species after the first season was Acacia auriculiformis. Satisfactory survival and growth were also obtained with Cassia siamea, Peltoforum ferruginum, Leucaena leucocephala (although this was later heavily damaged by wild rabbits) and Toona ciliata. The bamboo survived well but there was no culm formation during the experiment. In 1982 only 3 of the species were tested: A. auriculiformis, L. leucocephala (because of its fast growth rate) and Casuarina equisetifolia (which performed badly in 1981 but is suited to alkaline soils). All 3 species performed satisfactorily.

  18. Large litter sizes

    DEFF Research Database (Denmark)

    Sandøe, Peter; Rutherford, K.M.D.; Berg, Peer

    2012-01-01

    This paper presents some key results and conclusions from a review (Rutherford et al. 2011) undertaken regarding the ethical and welfare implications of breeding for large litter size in the domestic pig and about different ways of dealing with these implications. Focus is primarily on the direct...... possible to achieve a drop in relative piglet mortality and the related welfare problems. However, there will be a growing problem with the need to use foster or nurse sows which may have negative effects on both sows and piglets. This gives rise to new challenges for management....

  19. Experimental analysis of drainage and water storage of litter layers

    Science.gov (United States)

    Guevara-Escobar, A.; Gonzalez-Sosa, E.; Ramos-Salinas, M.; Hernandez-Delgado, G. D.

    2007-06-01

    Leaf litter overlying forested floors are important for erosion control and slope stability, but also reduces pasture growth in silvopastoral systems. Little information exists regarding the value of percolation and storage capacity parameters for litter layers. These estimates are needed for modelling better management practices for leaf litter. Therefore, this work measured the effect of four rainfall intensities: 9.8, 30.2, 40.4 and 70.9 mm h-1 on the hydrological response of layers of three materials: recently senesced poplar leaves, fresh grass and woodchips. Maximum storage (Cmax), defined as the detention of water immediately before rainfall cessation, increased with rainfall intensity. The magnitude of the increment was 0.2 mm between the lowest and highest rainfall intensities. Mean values of Cmax were: 1.27, 1.51, 1.67 and 1.65 mm for poplar leaves; 0.63 0.77, 0.73 and 0.76 for fresh grass and; 1.64, 2.23, 2.21 and 2.16 for woodchips. Drainage parameters were: 9.9, 8.8 and 2.2 mm-1 for poplar, grass and woodchips layers. An underlying soil matrix influenced the drainage flow from poplar leaf layers producing pseudo-Hortonian overland flow, but this occurred only when the rainfall intensity was 40.4 and 70.9 mm h-1 and accounted for 0.4 and 0.8‰ of total drainage. On the other hand, the presence of a poplar leaf layer had a damping effect on the drainage rate from the underlying soil matrix, particularly at intermediate rainfall intensities: 30.2 or 40.4 mm h-1.

  20. Factors influencing seed germination in Cerrado grasses

    OpenAIRE

    Kolb, Rosana Marta; Pilon, Natashi Aparecida Lima; Durigan, Giselda

    2016-01-01

    Few studies address the ecology of herbs of Cerrado grasslands, which are ecosystems where the long dry season, high temperatures, insolation, fire and invasive grasses greatly influencing germination and the establishment of plants. We assessed germination of 13 species of Poaceae from Cerrado grasslands under nursery conditions or in germination chambers, the latter with i) recently collected seeds and seeds after six months storage, ii) under constant and alternating temperatures, and iii)...

  1. Harm caused by Marine Litter

    NARCIS (Netherlands)

    Werner, S.; Budziak, A.; Franeker, van J.A.; Galgani, F.; Hanke, G.; Maes, T.; Matiddi, M.; Nilsson, P.; Oosterbaan, L.; Priestland, E.; Thompson, R.; Veiga, J.; Vlachogianni, T.

    2016-01-01

    Marine litter is a global concern with a range of problems associated to it, as recognised by the Marine Strategy Framework Directive (MSFD). Marine litter can impact organisms at different levels of biological organization and habitats in a number of ways namely: through entanglement in, or

  2. resistance of napier grass clones to napier grass stunt disease

    African Journals Online (AJOL)

    ACSS

    Napier grass (Pennisetum purpureum Schumach) is the major livestock fodder under intensive and semi-intensive systems in East Africa. However, the productivity of the grass is constrained by Napier grass Stunt Disease. (NSD). The purpose of this study was to identify Napier grass clones with resistance to NSD.

  3. Resistance of Napier grass clones to Napier grass Stunt Disease ...

    African Journals Online (AJOL)

    Napier grass (Pennisetum purpureum Schumach) is the major livestock fodder under intensive and semi-intensive systems in East Africa. However, the productivity of the grass is constrained by Napier grass Stunt Disease (NSD). The purpose of this study was to identify Napier grass clones with resistance to NSD.

  4. Recent invasion of buffel grass (Cenchrus ciliaris of a natural protected area from the southern Sonoran Desert Invasión reciente de zacate buffel (Cenchrus ciliaris en un área natural protegida del desierto sonorense

    Directory of Open Access Journals (Sweden)

    Erick De la Barrera

    2008-12-01

    Full Text Available The Centro Ecológico de Sonora is a natural protected area where the natural vegetation remained undisturbed at least until 1997. Since then, Cenchrus ciliaris has become a prominent element of the vegetation because of disturbance. Climate, soil properties, population structure and biological activity for C. ciliaris were studied to gain understanding of the ecological mechanisms that favored the invasion by this exotic grass. Mean air temperature and annual rainfall were 24.8°C and 302 mm. The soil was a loamy-sand that was poor in most nutrients, but particularly rich in phosphorus. Pennisetum ciliare was the most abundant species at the Centro Ecológico, representing over one third of total plant ground cover. Basal area for individual plants ranged from less than 1 cm² to almost 1 m². Living leaves per plant increased with precipitation, peaking at 199 leaves in March 2005, and no living leaves were found after 103 days without rain. The environmental conditions prevalent at Centro Ecológico are very favorable for C. ciliaris, whose establishment was apparently triggered by a major disturbance caused by the development of housing projects.El Centro Ecológico de Sonora es un área natural protegida donde la vegetación autóctona permaneció sin disturbios por lo menos hasta 1997. Desde entonces, Cenchrus ciliaris se ha convertido en un elemento prominente de la vegetación. Se estudiaron el clima, las propiedades del suelo, la estructura de la población y la actividad biológica de C. ciliaris, como una aproximación al entendimiento de los mecanismos ecológicos que favorecieron la invasión por este pasto exótico. La temperatura media del aire y la precipitación anual fueron de 24.8 °C y 302 mm. El suelo fue una arena limosa pobre en minerales, pero particularmente rica en fósforo. Cenchrus ciliaris fue la especie herbácea más abundante en el Centro Ecológico, representando más de un tercio de la cobertura vegetal. El

  5. Environmentally-friendly animal litter

    Energy Technology Data Exchange (ETDEWEB)

    Boxley, Chett; McKelvie, Jessica

    2012-08-28

    An animal litter composition including geopolymerized ash particulates having a network of repeating aluminum-silicon units is described herein. Generally, the animal litter is made from a quantity of a pozzolanic ash mixed with a sufficient quantity of water and an alkaline activator to initiate a geopolymerization reaction that forms geopolymerized ash. After the geopolymerized ash is formed, it is dried, broken into particulates, and sieved to a desired size. These geopolymerized ash particulates are used to make a non-clumping or clumping animal litter. Odor control is accomplished with the addition of a urease inhibitor, pH buffer, an odor eliminating agent, and/or fragrance.

  6. Den litterære blog

    DEFF Research Database (Denmark)

    Serup, Martin Glaz; Kromann, Thomas Hvid

    2012-01-01

    Hvad er en litterær blog og hvordan arbejder den som en aktiv del af den litterære offentlighed.......Hvad er en litterær blog og hvordan arbejder den som en aktiv del af den litterære offentlighed....

  7. Justifiability of Littering: An Empirical Investigation

    OpenAIRE

    Benno Torgler; Maria A. Garcia-Valinas; Alison Macintyre

    2008-01-01

    This paper investigates the relationship between voluntary participation in environmental organisations and the justifiability of littering behaviour. Previous empirical work regarding determinants of littering and littering behaviour remains scarce, particularly in socio-economic analysis. We address these deficiencies, demonstrating a strong empirical link between environmental participation and reduced public littering in the European Values Survey (EVS) data for 30 Western and Eastern Eur...

  8. GRASS GIS Vector Processing: Towards GRASS 7

    Science.gov (United States)

    Metz, Markus; Landa, Martin; Petrasova, Anna; Petras, Vaclav; Chemin, Yann; Neteler, Markus

    2014-05-01

    The upcoming GRASS GIS 7 release improves not only raster processing and general design but the vector processing in the first place. GRASS GIS, as a topological GIS, recognizes that the topology plays the key role in the vector processing and analysis. Topology ensures that adjacent geographic components in a single vector map are related. In contrast to non-topological GIS, a border common to two areas exists only once and is shared between the two areas. Topological representation of vector data helps to produce and maintain vector maps with clean geometry as well as enables the user to perform certain analyses that can not be conducted with non-topological or spaghetti data. Non-topological vector data are automatically converted to a topological representation upon import. Further more, various cleaning tools exist to remove non-trivial topological errors. In the upcoming GRASS GIS 7 release the vector library was particularly improved to make it faster and more efficient with an improved internal vector file format. This new topological format reduces memory and disk space requirements, leading to a generally faster processing. Opening an existing vector requires less memory providing additionally support for large files. The new spatial index performs queries faster (compared to GRASS GIS 6 more than 10 times for large vectors). As a new option the user can select a file-based version of the spatial index for large vector data. All topological cleaning tools have been optimized with regard to processing speed, robustness, and system requirements. The topological engine comes with a new prototype for direct read/write support of Simple Features API/OGR. Additionally vector data can be directly exchanged with topological PostGIS 2 databases. Considering the wide spread usage of ESRI Shapefile, a non-topological format for vector data exchange, it is particularly advantageous that GRASS GIS 7 offers advanced cleaning tools. For power users and programmers, the

  9. Managing soil nitrogen to restore annual grass-infested plant communities: Effective strategy or incomplete framework?

    Science.gov (United States)

    J. J. James; R. E. Drenovsky; T. A. Monaco; M. J. Rinella

    2011-01-01

    Theoretical and empirical work has established a positive relationship between resource availability and habitat invasibility. For nonnative invasive annual grasses, similar to other invasive species, invader success has been tied most often to increased nitrogen (N) availability. These observations have led to the logical assumption that managing soils for low N...

  10. Identifying Sources of Marine Litter

    OpenAIRE

    VEIGA Joana Mira; FLEET David; KINSEY Sue; NILSSON Per; VLACHOGIANNI Thomais; WERNER Stefanie; GALGANI Francois; THOMPSON Richard; DAGEVOS Jeroen; GAGO Jesus; SOBRAL Paula; CRONIN Richard

    2016-01-01

    Marine litter is a global problem causing harm to marine wildlife, coastal communities and maritime activities. It also embodies an emerging concern for human health and safety. The reduction of marine litter pollution poses a complex challenge for humankind, requiring adjustments in human behaviour as well as in the different phases of the life-cycle of products and across multiple economic sectors. The Marine Strategy Framework Directive (MSFD) requires European Member States to monitor...

  11. Leaf litter quality drives litter mixing effects through complementary resource use among detritivores.

    NARCIS (Netherlands)

    Vos, V.C.A.; van Ruijven, J.; Berg, M.P.; Peeters, E.T.H.M.; Berendse, F.

    2013-01-01

    To comprehend the potential consequences of biodiversity loss on the leaf litter decomposition process, a better understanding of its underlying mechanisms is necessary. Here, we hypothesize that positive litter mixture effects occur via complementary resource use, when litter species complement

  12. Leaf litter quality drives litter mixing effects through complementary resource use among detritivores

    NARCIS (Netherlands)

    Vos, V.C.A.; Ruijven, van J.; Berg, M.P.; Peeters, E.T.H.M.; Berendse, F.

    2013-01-01

    To comprehend the potential consequences of biodiversity loss on the leaf litter decomposition process, a better understanding of its underlying mechanisms is necessary. Here, we hypothesize that positive litter mixture effects occur via complementary resource use, when litter species complement

  13. Spatial and temporal variability of guinea grass (Megathyrsus maximus) fuel loads and moisture on Oahu, Hawaii

    Science.gov (United States)

    Lisa M. Ellsworth; Creighton M. Litton; Andrew D. Taylor; J. Boone Kauffman

    2013-01-01

    Frequent wildfires in tropical landscapes dominated by non-native invasive grasses threaten surrounding ecosystems and developed areas. To better manage fire, accurate estimates of the spatial and temporal variability in fuels are urgently needed. We quantified the spatial variability in live and dead fine fuel loads and moistures at four guinea grass (...

  14. Seed origin determines the range expansion of the clonal grass Elymus athericus

    NARCIS (Netherlands)

    Bockelmann, Anna-Christina; Wels, Thies; Bakker, Jan P.

    2011-01-01

    The recent invasion of clonal grasses to novel habitats poses a threat to biodiversity in various habitats. Elymus athericus, a clonal grass of north-western European salt marshes, is currently increasing in abundance and invading new habitats. In this study, we analyzed controlling factors for

  15. High litter moisture content suppresses litter ammonia volatilization.

    Science.gov (United States)

    Miles, D M; Rowe, D E; Cathcart, T C

    2011-07-01

    With global food demand expected to increase by 100% in the next 50 yr, urgency to combine comprehensive strategies for sustainable, efficacious, and environmentally sensible agronomic practices has never been greater. One effort for US meat bird management is to reduce NH(3) volatilization from litter to create a better growing environment for the birds, improve production efficiency, retain N in litter for fertilizer value, and negate the detrimental environmental impacts of NH(3) loss to the air. To derive the fundamental effects of temperature and moisture on litter NH(3) volatilization over the range of conditions found in commercial houses, experiments were conducted using commercial broiler litter that had moisture contents of approximately 20 to 55% while controlling temperatures ranging from 18.3 to 40.6°C. Litter samples (100 g) were placed in 1-L containers that received humidified air at approximately 113 mL/min. Volatilized NH(3) in exhaust air was captured in H(3)BO(3) traps. Ammonia loss (log(10) transformation) was modeled via an equation using linear coefficients for temperature and moisture, an interaction term for temperature × moisture, and a quadratic term for moisture. The surface responses resembled parabolic cylinders, indicating a critical moisture level at which NH(3) no longer increases but is diminished as moisture continues to increase. The critical moisture level lies between 37.4 and 51.1% litter moisture, depending on the temperature. An increase in temperature consistently increased NH(3) generation. When the temperature extremes were compared, the maximum NH(3) was up to 7 times greater at 40.6 vs. 18.3°C. The upper moisture limit at which NH(3) release is maximized and subsequently arrested as moisture continues to increase had not been defined previously for commercial broiler litter. The poultry industry and researchers can use these results as a decision tool to enable management strategies that limit NH(3) production.

  16. Short-term Dynamics of Photopriming Increase Carbon Loss During Litter Decomposition

    Science.gov (United States)

    Lin, Y.; King, J. Y.; Karlen, S. D.; Ralph, J.

    2017-12-01

    Solar radiation plays a key role in carbon (C) cycling by increasing the decomposition rates of plant litter through photodegradation. This process is particularly important in drylands where solar radiation is high and microbial activity may be limited by water availability. One mechanism of photodegradation may be the facilitation of microbial decomposition of litter by altering litter chemistry and consequently degradability, termed photopriming. However, it remains unclear to what extent photopriming contributes to litter decomposition. We evaluated photopriming by ultraviolet (UV) radiation through two laboratory experiments. In one experiment, we found that four months of UV exposure increased mass loss by 3-4% compared to dark treatment in two of three litter species commonly found in California oak savanna; however, UV exposure did not alter litter degradability as measured by microbial respiration in an incubation study. UV exposure had limited effects on lignin and other cell wall structures, but one month of microbial decomposition in the dark significantly reduced lignin β-aryl ether inter-unit linkages and acetylated xylans, which interestingly was the same pattern seen in litter exposed to UV radiation under field conditions and may account for the significant effects of UV exposure on litter mass loss observed in situ. These results indicate that microbial decomposition, not abiotic photodegradation, was ultimately responsible for changes in litter chemistry observed in the field. In a separate experiment, litter of a common grass was incubated for 128 days under either alternating UV radiation and dark conditions at two-day intervals or continuous darkness. During the second half of the experiment, alternating UV exposure increased CO2 production by 35% compared to continuous darkness, suggesting that UV exposure induces subtle but important changes in litter chemistry that facilitate microbial decomposition on a temporal scale of days. Together

  17. GUI development for GRASS GIS

    Directory of Open Access Journals (Sweden)

    Martin Landa

    2007-12-01

    Full Text Available This article discusses GUI development for GRASS GIS. Sophisticated native GUI for GRASS is one of the key points (besides the new 2D/3D raster library, vector architecture improvements, etc. for the future development of GRASS. In 2006 the GRASS development team decided to start working on the new generation of GUI instead of improving the current GUI based on Tcl/Tk.

  18. Have grass carp driven declines in macrophyte occurrence and ...

    African Journals Online (AJOL)

    The Vaal River, South Africa, historically had a rich diversity of native submerged macrophytes with at least 13 species from 5 families recorded. ... in the populations of invasive alien grass carp Ctenopharyngodon idella Cuvier & Valenciennes (Cyprinidae) in the river, where populations have been a concern since 2005.

  19. Metagenomics at Grass Roots

    Indian Academy of Sciences (India)

    tostabilize metal-contaminated soils, and sequester toxic metals. Identification of rhizospheric microbial communities that toler- ate contaminants and promote transformations that render the soil less toxic, are invaluable for phytoremediation and restoration of degraded lands. An Example of Bacterial Communities in Grass ...

  20. Metagenomics at Grass Roots

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 22; Issue 3. Metagenomics at Grass Roots. Sudeshna ... benefit human health, agriculture, and ecosystemfunctions. This article provides a brief history of technicaladvances in metagenomics, including DNA sequencing methods,and some case studies.

  1. Using multi-date satellite imagery to monitor invasive grass species distribution in post-wildfire landscapes: An iterative, adaptable approach that employs open-source data and software

    Science.gov (United States)

    West, Amanda M.; Evangelista, Paul H.; Jarnevich, Catherine S.; Kumar, Sunil; Swallow, Aaron; Luizza, Matthew W.; Chignell, Stephen M.

    2017-07-01

    Among the most pressing concerns of land managers in post-wildfire landscapes are the establishment and spread of invasive species. Land managers need accurate maps of invasive species cover for targeted management post-disturbance that are easily transferable across space and time. In this study, we sought to develop an iterative, replicable methodology based on limited invasive species occurrence data, freely available remotely sensed data, and open source software to predict the distribution of Bromus tectorum (cheatgrass) in a post-wildfire landscape. We developed four species distribution models using eight spectral indices derived from five months of Landsat 8 Operational Land Imager (OLI) data in 2014. These months corresponded to both cheatgrass growing period and time of field data collection in the study area. The four models were improved using an iterative approach in which a threshold for cover was established, and all models had high sensitivity values when tested on an independent dataset. We also quantified the area at highest risk for invasion in future seasons given 2014 distribution, topographic covariates, and seed dispersal limitations. These models demonstrate the effectiveness of using derived multi-date spectral indices as proxies for species occurrence on the landscape, the importance of selecting thresholds for invasive species cover to evaluate ecological risk in species distribution models, and the applicability of Landsat 8 OLI and the Software for Assisted Habitat Modeling for targeted invasive species management.

  2. Using multi-date satellite imagery to monitor invasive grass species distribution in post-wildfire landscapes: An iterative, adaptable approach that employs open-source data and software

    Science.gov (United States)

    West, Amanda M.; Evangelista, Paul H.; Jarnevich, Catherine S.; Kumar, Sunil; Swallow, Aaron; Luizza, Matthew; Chignell, Steve

    2017-01-01

    Among the most pressing concerns of land managers in post-wildfire landscapes are the establishment and spread of invasive species. Land managers need accurate maps of invasive species cover for targeted management post-disturbance that are easily transferable across space and time. In this study, we sought to develop an iterative, replicable methodology based on limited invasive species occurrence data, freely available remotely sensed data, and open source software to predict the distribution of Bromus tectorum (cheatgrass) in a post-wildfire landscape. We developed four species distribution models using eight spectral indices derived from five months of Landsat 8 Operational Land Imager (OLI) data in 2014. These months corresponded to both cheatgrass growing period and time of field data collection in the study area. The four models were improved using an iterative approach in which a threshold for cover was established, and all models had high sensitivity values when tested on an independent dataset. We also quantified the area at highest risk for invasion in future seasons given 2014 distribution, topographic covariates, and seed dispersal limitations. These models demonstrate the effectiveness of using derived multi-date spectral indices as proxies for species occurrence on the landscape, the importance of selecting thresholds for invasive species cover to evaluate ecological risk in species distribution models, and the applicability of Landsat 8 OLI and the Software for Assisted Habitat Modeling for targeted invasive species management.

  3. Effects of Plant Functional Group Loss on Soil Microbial Community and Litter Decomposition in a Steppe Vegetation

    Directory of Open Access Journals (Sweden)

    Chunwang Xiao

    2017-11-01

    Full Text Available Globally, many terrestrial ecosystems are experiencing a rapid loss of biodiversity. Continued improvements in our understanding of interrelationships between plant diversity and soil microbes are critical to address the concern over the consequences of the decline in biodiversity on ecosystem functioning and services. By removing forbs, or grasses, or, to an extreme scenario, both forbs and grasses in a steppe vegetation in Inner Mongolia, we studied how plant functional group (PFG loss affects soil microbial community composition using phospholipid fatty acid analysis (PLFA and litter decomposition using a litter-bag method. PFG loss significantly decreased above- and below-ground plant biomass, soil microbial biomass carbon (SMBC and nitrogen (SMBN, but had no effect on the ratio of SMBC to SMBN. Although the ratio of fungal to bacterial PLFAs remained unaffected, PFG loss significantly reduced the amount of bacterial, fungal, and total PLFAs. PFG loss decreased litter monthly mass loss and decay constant, and such decrease was significant when both forbs and grasses were removed. Our results provide robust evidence that PFG loss in grassland ecosystem can lead to a rapid response of soil microbial activity which may affect litter decomposition and soil nutrient cycling, suggesting that the assessment of plant–microbe interactions in soils is an integral component of ecosystem response to biodiversity loss.

  4. Separating the mink dam from the litter at 7 or 8 weeks after delivery

    DEFF Research Database (Denmark)

    Malmkvist, Jens; Palme, Rupert; Larsen, Torben

    2015-01-01

    The optimal timing of separating the mink dam from the litter is suggested to be a balance between the partly conflicting needs of the mother and the kits. Early removal of the dam or partial removal of the litter may protect the dam against exhaustion. Little is known about the maternal motivation...... (8w, N=189) after birth. The aim was to investigate whether the dams had a different motivation to take care of the litter after 7 and 8 weeks, estimated by non-invasive determination of cortisol (FCM: Faecal Corticsol Metabolites) and dam calls the first week after separation. The two treatment.......014). Likewise, the dam calls increased on the separation day, peaking on the first day after separation (D1). The proportion of dams with calls decreased with litter age at separation (P=0.024). We interpret these results as a higher maternal motivation in dams at 7 weeks than at 8 weeks after delivery...

  5. Determinants of Littering: An Experimental Analysis

    OpenAIRE

    Fatima Salim Khawaja; Anwar Shah

    2013-01-01

    Littering, the improper disposal of small quantities of waste, is one of the main causes of environmental degradation. To protect the environment from this degradation, we need to factor out the determinants of littering behaviour. In this study, we conduct a controlled laboratory experiment to examine whether people would avoid littering if the social cost of this behaviour was internalised. Based on the microeconomic theory relating to externality, we test whether penalising littering decre...

  6. Riverine Litter Monitoring - Options and Recommendations

    OpenAIRE

    GONZALEZ FERNANDEZ DANIEL; HANKE Georg; TWEEHUYSEN Gijsbert; BELLERT Bert; HOLZHAUER Marloes; PALATINUS Andreja; HOHENBLUM Philipp; OOSTERBAAN Lex

    2016-01-01

    Marine litter is an issue of global concern as recognized by the Marine Strategy Framework Directive (MSFD). The establishment of programmes of measures, aiming to reduce plastics and its possible impacts, requires identifying and quantifying sources of litter and their pathways to the marine environment. In this regard, riverine litter input is estimated to be a major contributor, but there is no comprehensive information about the amount of litter being transported through rivers into the s...

  7. Linking dominant Hawaiian tree species to understory development in recovering pastures via impacts on soils and litter

    Science.gov (United States)

    Yelenik, Stephanie G.

    2017-01-01

    Large areas of tropical forest have been cleared and planted with exotic grass species for use as cattle pasture. These often remain persistent grasslands after grazer removal, which is problematic for restoring native forest communities. It is often hoped that remnant and/or planted trees can jump-start forest succession; however, there is little mechanistic information on how different canopy species affect community trajectories. To investigate this, I surveyed understory communities, exotic grass biomass, standing litter pools, and soil properties under two dominant canopy trees—Metrosideros polymorpha (‘ōhi‘a) and Acacia koa (koa)—in recovering Hawaiian forests. I then used structural equation models (SEMs) to elucidate direct and indirect effects of trees on native understory. Native understory communities developed under ‘ōhi‘a, which had larger standing litter pools, lower soil nitrogen, and lower exotic grass biomass than koa. This pattern was variable, potentially due to historical site differences and/or distance to intact forest. Koa, in contrast, showed little understory development. Instead, data suggest that increased soil nitrogen under koa leads to high grass biomass that stalls native recruitment. SEMs suggested that indirect effects of trees via litter and soils were as or more important than direct effects for determining native cover. It is suggested that diverse plantings which incorporate species that have high carbon to nitrogen ratios may help ameliorate the negative indirect effects of koa on natural understory regeneration.

  8. System design of a litter collecting robot

    NARCIS (Netherlands)

    Bonnema, Gerrit Maarten

    2012-01-01

    Litter in public places is a serious problem. Not only because of the obvious dirtiness, but also because litter attracts more litter and can cause the winding down of an area leading to large negative financial and social consequences. To avoid this, public areas have been kept clean by humans. In

  9. Influence of packaging design on littering behavior

    NARCIS (Netherlands)

    Wever, R.

    2006-01-01

    Litter is an environmental and social problem that is closely related to packaging. Many attempts have been made to reduce litter. So far these attempts have mainly focused on influencing littering behavior either through general campaigns or through manipulating the environment. The latter might be

  10. Nutrient Dynamics and Litter Decomposition in Leucaena ...

    African Journals Online (AJOL)

    Nutrient contents and rate of litter decomposition were investigated in Leucaena leucocephala plantation in the University of Agriculture, Abeokuta, Ogun State, Nigeria. Litter bag technique was used to study the pattern and rate of litter decomposition and nutrient release of Leucaena leucocephala. Fifty grams of oven-dried ...

  11. Book title: Exotic brome grasses in arid and semi-arid ecosystems of the western US: causes, consequences, and management implications

    Science.gov (United States)

    Exotic invasive annual grass research and management in arid and semiarid ecosystems of the western US have historically focused on the outcome of efforts to reduce weed abundance. Given the current impact of invasive annual grasses and their continued spread in this region, we assessed components ...

  12. Neotropical woodlice (isopoda colonizing leaf-litter of pioneer plants in a coal residue disposal environment

    Directory of Open Access Journals (Sweden)

    Luciana Regina Podgaiski

    2011-06-01

    Full Text Available The irregular disposal of coal combustion residues has adverse impacts on terrestrial ecosystems. Pioneer plants and soil invertebrates play an important role in the recovery of these areas. The goal of this study was to investigate the colonization patterns of terrestrial isopods (Oniscidea in leaf litter of three spontaneous pioneer plants (grass - Poaceae, shrub - Euphorbiaceae, tree - Anarcadiaceae at sites used for fly ash or boiler slag disposal. The experiment consisted of eight blocks (four per disposal site of 12 litter bags each (four per plant species that were randomly removed after 6, 35, 70 or 140 days of field exposure. Three isopod species were found in the litter bags: Atlantoscia floridana (van Name, 1940 (Philosciidae; n = 116, Benthana taeniata Araujo & Buckup, 1994 (Philosciidae; n = 817 and Balloniscus sellowii (Brandt, 1833 (Balloniscidae; n = 48. The isopods colonized the three leaf-litter species equally during the exposure period. However, the pattern of leaf-litter colonization by these species suggests a conflict of objectives between high quality food and shelter availability. The occurrence of A. floridana and the abundance and fecundity of B. taeniata were influenced by the residue type, indicating that the isopods have different degrees of tolerance to the characteristics of the studied sites. Considering that terrestrial isopods are abundant detritivores and stimulate the humus-forming processes, it is suggested that they could have an indirect influence on the soil restoration of this area.

  13. Impacts of emerald ash borer-induced tree mortality on leaf litter arthropods and exotic earthworms

    Science.gov (United States)

    Michael D. Ulyshen; Wendy S. Klooster; William T. Barrington; Daniel A. Herns

    2011-01-01

    Because leaf litter occurs at the interface between the soil and atmosphere, the invertebrates inhabiting it represent important linkages between above- and below-ground food webs. The responses of these organisms to forest disturbance brought about by invasive species should therefore have far-reaching ecological effects. The purpose of this study was to explore how...

  14. Factors influencing seed germination in Cerrado grasses

    Directory of Open Access Journals (Sweden)

    Rosana Marta Kolb

    2016-03-01

    Full Text Available Few studies address the ecology of herbs of Cerrado grasslands, which are ecosystems where the long dry season, high temperatures, insolation, fire and invasive grasses greatly influencing germination and the establishment of plants. We assessed germination of 13 species of Poaceae from Cerrado grasslands under nursery conditions or in germination chambers, the latter with i recently collected seeds and seeds after six months storage, ii under constant and alternating temperatures, and iii in the presence and absence of light. Germinability, mean germination time (MGT and required light were quantified to elucidate factors involved in successful germination. Germinability was low for most grasses, probably because of low seed viability. For most species, germinability and MGT were not altered by seed storage. Germination percentages were higher at alternating temperatures and in the presence of light, factors that are more similar to natural environmental situations compared with constant temperature or the absence of light. Our findings indicate that alternating temperatures and light incidence are key factors for germination of species of Poaceae. The maintenance of these environmental factors, which are crucial for the conservation of Cerrado grasslands, depends on appropriate management interventions, such as fire management and the control of biological invasion.

  15. Controle de invasão biológica por capim-anonni em margem viária mediante a introdução de gramíneas Control of biological invasion by South African lovegrass on a roadside by introducing grasses

    Directory of Open Access Journals (Sweden)

    Renato Borges de Medeiros

    2011-02-01

    Full Text Available Objetivou-se avaliar o controle da invasão biológica por Eragrostis plana Nees (capim-anonni em margens de rodovia com a introdução de gramíneas concorrentes associada a práticas de preparo do solo e adubação. O delineamento experimental foi em blocos casualizados com parcelas subdivididas e três repetições. Nas parcelas, foram avaliadas duas práticas de preparo do solo: solo subsolado e gradeado com aplicação de calcário e fósforo; e solo apenas subsolado, e nas subparcelas, as espécies de gramíneas: capim-mombaça (Megathyrsus maximus (Jacq. B. K. Simon & S. W. L. Jacobs; capim-kazangula (Setaria sphacelata (Schumach. Stapf & C. E. Hubb. ex M. B. Moss; mistura de sementes de três gramíneas nativas, grama-de-forquilha (Paspalum notatum Alain ex Flüggé, macega-do-banhado (Paspalum regnelli Mez e capim-das-roças (Paspalum urvillei Steud.; avaliadas em comparação a uma subparcela de exclusão (testemunha. Nos levantamentos florísticos, realizados em 8 de janeiro de 2005, e após o plantio, em 26 de janeiro e 25 de junho de 2006, observou-se alta riqueza florística, com 86 espécies botânicas distribuídas em 29 famílias e 21% de espécies exóticas. O solo subsolado, gradeado, corrigido e adubado, associado às introduções de M. maximus e S. kazungula, foram as alternativas que mais contribuíram para reduzir a cobertura de E. plana. As gramíneas nativas presentes na vegetação do acostamento, Paspalum plicatulum Mitchx, Piptochaetium montevidense (Spreng. Parodi e a espécie nativa introduzida (Paspalum urvillei têm potencial para controlar a invasão de E. plana.The objective of this study was to control biological invasion by Eragrostis plana Nees (South African lovegrass on a roadside by introducing competitor grasses associated with soil management and fertilization practices. The experimental design was a complete randomized block with split-plots parcels and three replications. In the parcels, it was

  16. Climate and litter quality differently modulate the effects of soil fauna on litter decomposition across biomes.

    Science.gov (United States)

    García-Palacios, Pablo; Maestre, Fernando T; Kattge, Jens; Wall, Diana H

    2013-08-01

    Climate and litter quality have been identified as major drivers of litter decomposition at large spatial scales. However, the role played by soil fauna remains largely unknown, despite its importance for litter fragmentation and microbial activity. We synthesised litterbag studies to quantify the effect sizes of soil fauna on litter decomposition rates at the global and biome scales, and to assess how climate, litter quality and soil fauna interact to determine such rates. Soil fauna consistently enhanced litter decomposition at both global and biome scales (average increment ~ 37%). [corrected]. However, climate and litter quality differently modulated the effects of soil fauna on decomposition rates between biomes, from climate-driven biomes to those where climate effects were mediated by changes in litter quality. Our results advocate for the inclusion of biome-specific soil fauna effects on litter decomposition as a mean to reduce the unexplained variation in large-scale decomposition models. © 2013 John Wiley & Sons Ltd/CNRS.

  17. Plant litter functional diversity effects on litter mass loss depend on the macro-detritivore community.

    Science.gov (United States)

    Patoine, Guillaume; Thakur, Madhav P; Friese, Julia; Nock, Charles; Hönig, Lydia; Haase, Josephine; Scherer-Lorenzen, Michael; Eisenhauer, Nico

    2017-11-01

    A better understanding of the mechanisms driving litter diversity effects on decomposition is needed to predict how biodiversity losses affect this crucial ecosystem process. In a microcosm study, we investigated the effects of litter functional diversity and two major groups of soil macro-detritivores on the mass loss of tree leaf litter mixtures. Furthermore, we tested the effects of litter trait community means and dissimilarity on litter mass loss for seven traits relevant to decomposition. We expected macro-detritivore effects on litter mass loss to be most pronounced in litter mixtures of high functional diversity. We used 24 leaf mixtures differing in functional diversity, which were composed of litter from four species from a pool of 16 common European tree species. Earthworms, isopods, or a combination of both were added to each litter combination for two months. Litter mass loss was significantly higher in the presence of earthworms than in that of isopods, whereas no synergistic effects of macro-detritivore mixtures were found. The effect of functional diversity of the litter material was highest in the presence of both macro-detritivore groups, supporting the notion that litter diversity effects are most pronounced in the presence of different detritivore species. Species-specific litter mass loss was explained by nutrient content, secondary compound concentration, and structural components. Moreover, dissimilarity in N concentrations increased litter mass loss, probably because detritivores having access to nutritionally diverse food sources. Furthermore, strong competition between the two macro-detritivores for soil surface litter resulted in a decrease of survival of both macro-detritivores. These results show that the effects of litter functional diversity on decomposition are contingent upon the macro-detritivore community and composition. We conclude that the temporal dynamics of litter trait diversity effects and their interaction with

  18. Non-native grass removal and shade increase soil moisture and seedling performance during Hawaiian dry forest restoration

    Science.gov (United States)

    Jared M. Thaxton; Susan Cordell; Robert J. Cabin; Darren R. Sandquist

    2012-01-01

    Invasive non-native species can create especially problematic restoration barriers in subtropical and tropical dry forests. Native dry forests in Hawaii presently cover less than 10% of their original area. Many sites that historically supported dry forest are now completely dominated by non-native species, particularly grasses. Within a grass-dominated site in leeward...

  19. Marine litter prediction by artificial intelligence

    International Nuclear Information System (INIS)

    Balas, Can Elmar; Ergin, Aysen; Williams, Allan T.; Koc, Levent

    2004-01-01

    Artificial intelligence techniques of neural network and fuzzy systems were applied as alternative methods to determine beach litter grading, based on litter surveys of the Antalya coastline (the Turkish Riviera). Litter measurements were categorized and assessed by artificial intelligence techniques, which lead to a new litter categorization system. The constructed neural network satisfactorily predicted the grading of the Antalya beaches and litter categories based on the number of litter items in the general litter category. It has been concluded that, neural networks could be used for high-speed predictions of litter items and beach grading, when the characteristics of the main litter category was determined by field studies. This can save on field effort when fast and reliable estimations of litter categories are required for management or research studies of beaches--especially those concerned with health and safety, and it has economic implications. The main advantages in using fuzzy systems are that they consider linguistic adjectival definitions, e.g. many/few, etc. As a result, additional information inherent in linguistic comments/refinements and judgments made during field studies can be incorporated in grading systems

  20. Marine litter prediction by artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Balas, Can Elmar; Ergin, Aysen; Williams, Allan T.; Koc, Levent

    2004-03-01

    Artificial intelligence techniques of neural network and fuzzy systems were applied as alternative methods to determine beach litter grading, based on litter surveys of the Antalya coastline (the Turkish Riviera). Litter measurements were categorized and assessed by artificial intelligence techniques, which lead to a new litter categorization system. The constructed neural network satisfactorily predicted the grading of the Antalya beaches and litter categories based on the number of litter items in the general litter category. It has been concluded that, neural networks could be used for high-speed predictions of litter items and beach grading, when the characteristics of the main litter category was determined by field studies. This can save on field effort when fast and reliable estimations of litter categories are required for management or research studies of beaches--especially those concerned with health and safety, and it has economic implications. The main advantages in using fuzzy systems are that they consider linguistic adjectival definitions, e.g. many/few, etc. As a result, additional information inherent in linguistic comments/refinements and judgments made during field studies can be incorporated in grading systems.

  1. Initial Soil Organic Matter Content Influences the Storage and Turnover of Litter-, Root- and Soil Carbon in Grasslands

    Science.gov (United States)

    Liu, L.; Xu, S.; Li, P.; Sayer, E. J.

    2017-12-01

    Grassland degradation is a worldwide problem that often leads to substantial loss of soil organic matter (SOM). Understanding how SOM content influences the stabilization of plant carbon (C) to form soil C is important to evaluate the potential of degraded grasslands to sequester additional C. We conducted a greenhouse experiment using C3 soils with six levels of SOM content and planted the C4 grass Cleistogenes squarrosa and/or added its litter to investigate how SOM content regulates the storage of new soil C derived from litter and roots, the decomposition of extant soil C, and the formation of soil aggregates. We found that microbial biomass carbon (MBC) increased with SOM content, and increased the mineralization of litter C. Both litter addition and planted treatments increased the amount of new C inputs to soil. However, litter addition had no significant impacts on the mineralization of extant soil C, but the presence of living roots significantly accelerated it. Thus, by the end of the experiment, soil C content was significantly higher in the litter addition treatments, but was not affected by planted treatments. The soil macroaggregate fraction increased with SOM content and was positively related to MBC. Overall, our study suggests that as SOM content increases, plant growth and soil microbes become more active, which allows microbes to process more plant-derived C and increases new soil C formation. The interactions between SOM content and plant C inputs should be considered when evaluating soil C turnover in degraded grasslands.

  2. Association between litterers' profile and littering behavior: A chi-square approach

    Science.gov (United States)

    Asmui, Mas'udah; Zaki, Suhanom Mohd; Wahid, Sharifah Norhuda Syed; Mokhtar, Noorsuraya Mohd; Harith, Siti Suhaila

    2017-05-01

    Littering is not a novelty, yet a prolonged issue. The solutions have been discussed for a long time; however this issue still remains unresolved. Littering is commonly associated with littering behavior and awareness. The littering behavior is normally influenced by the litter profile such as gender, family income, education level and age. Jengka Street market, which is located in Pahang, is popularly known as a trade market. It offers diversities of wet and dry goods and is awaited by local residents and tourists. This study analyzes association between litterers' profile and littering behavior. Littering behavior is measured based on factors of trash bin facilities, awareness campaign and public littering behavior. 114 respondents were involved in this study with 62 (54.39%) are female aged more than 18 years old and majority of these female respondents are diploma holders. In addition, 78.95% of the respondents have family income below than RM3,000.00 per month. Based on the data analysis, it was found that first-time visitors littered higher than frequent visitors, lack of providing trash bin facilities contributes to positive littering behavior and there is a significant association between litterers' age and littering behavior by using chi-square approach.

  3. Dual role of lignin in plant litter decomposition in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Ballaré, Carlos L

    2010-03-09

    Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems.

  4. Cigarette Litter: Smokers’ Attitudes and Behaviors

    Science.gov (United States)

    Rath, Jessica M.; Rubenstein, Rebecca A.; Curry, Laurel E.; Shank, Sarah E.; Cartwright, Julia C.

    2012-01-01

    Cigarette butts are consistently the most collected items in litter clean-up efforts, which are a costly burden to local economies. In addition, tobacco waste may be detrimental to our natural environment. The tobacco industry has conducted or funded numerous studies on smokers’ littering knowledge and behavior, however, non-industry sponsored research is rare. We sought to examine whether demographics and smokers’ knowledge and beliefs toward cigarette waste as litter predicts littering behavior. Smokers aged 18 and older (n = 1,000) were interviewed about their knowledge and beliefs towards cigarette waste as litter. Respondents were members of the Research Now panel, an online panel of over three million respondents in the United States. Multivariate logistic regressions were conducted to determine factors significantly predictive of ever having littered cigarette butts or having littered cigarette butts within the past month (p-value littered cigarette butts at least once in their life, by disposing of them on the ground or throwing them out of a car window. Over half (55.7%) reported disposing of cigarette butts on the ground, in a sewer/gutter, or down a drain in the past month. Those who did not consider cigarette butts to be litter were over three and half times as likely to report having ever littered cigarette butts (OR = 3.68, 95%CI = 2.04, 6.66) and four times as likely to have littered cigarette butts in the past month (OR = 4.00, 95%CI = 2.53, 6.32). Males were significantly more likely to have littered cigarette butts in the past month compared to females (OR = 1.49, 95%CI = 1.14, 1.94). Holding the belief that cigarette butts are not litter was the only belief in this study that predicted ever or past-month littering of cigarette waste. Messages in anti-cigarette-litter campaigns should emphasize that cigarette butts are not just litter but are toxic waste and are harmful when disposed of improperly. PMID:22829798

  5. Cigarette litter: smokers' attitudes and behaviors.

    Science.gov (United States)

    Rath, Jessica M; Rubenstein, Rebecca A; Curry, Laurel E; Shank, Sarah E; Cartwright, Julia C

    2012-06-01

    Cigarette butts are consistently the most collected items in litter clean-up efforts, which are a costly burden to local economies. In addition, tobacco waste may be detrimental to our natural environment. The tobacco industry has conducted or funded numerous studies on smokers' littering knowledge and behavior, however, non-industry sponsored research is rare. We sought to examine whether demographics and smokers' knowledge and beliefs toward cigarette waste as litter predicts littering behavior. Smokers aged 18 and older (n = 1,000) were interviewed about their knowledge and beliefs towards cigarette waste as litter. Respondents were members of the Research Now panel, an online panel of over three million respondents in the United States. Multivariate logistic regressions were conducted to determine factors significantly predictive of ever having littered cigarette butts or having littered cigarette butts within the past month (p-value littered cigarette butts at least once in their life, by disposing of them on the ground or throwing them out of a car window. Over half (55.7%) reported disposing of cigarette butts on the ground, in a sewer/gutter, or down a drain in the past month. Those who did not consider cigarette butts to be litter were over three and half times as likely to report having ever littered cigarette butts (OR = 3.68, 95%CI = 2.04, 6.66) and four times as likely to have littered cigarette butts in the past month (OR = 4.00, 95%CI = 2.53, 6.32). Males were significantly more likely to have littered cigarette butts in the past month compared to females (OR = 1.49, 95%CI = 1.14, 1.94). Holding the belief that cigarette butts are not litter was the only belief in this study that predicted ever or past-month littering of cigarette waste. Messages in anti-cigarette-litter campaigns should emphasize that cigarette butts are not just litter but are toxic waste and are harmful when disposed of improperly.

  6. Cigarette Litter: Smokers’ Attitudes and Behaviors

    Directory of Open Access Journals (Sweden)

    Julia C. Cartwright

    2012-06-01

    Full Text Available Cigarette butts are consistently the most collected items in litter clean-up efforts, which are a costly burden to local economies. In addition, tobacco waste may be detrimental to our natural environment. The tobacco industry has conducted or funded numerous studies on smokers’ littering knowledge and behavior, however, non-industry sponsored research is rare. We sought to examine whether demographics and smokers’ knowledge and beliefs toward cigarette waste as litter predicts littering behavior. Smokers aged 18 and older (n = 1,000 were interviewed about their knowledge and beliefs towards cigarette waste as litter. Respondents were members of the Research Now panel, an online panel of over three million respondents in the United States. Multivariate logistic regressions were conducted to determine factors significantly predictive of ever having littered cigarette butts or having littered cigarette butts within the past month (p-value < 0.05. The majority (74.1% of smokers reported having littered cigarette butts at least once in their life, by disposing of them on the ground or throwing them out of a car window. Over half (55.7% reported disposing of cigarette butts on the ground, in a sewer/gutter, or down a drain in the past month. Those who did not consider cigarette butts to be litter were over three and half times as likely to report having ever littered cigarette butts (OR = 3.68, 95%CI = 2.04, 6.66 and four times as likely to have littered cigarette butts in the past month (OR = 4.00, 95%CI = 2.53, 6.32. Males were significantly more likely to have littered cigarette butts in the past month compared to females (OR = 1.49, 95%CI = 1.14, 1.94. Holding the belief that cigarette butts are not litter was the only belief in this study that predicted ever or past-month littering of cigarette waste. Messages in anti-cigarette-litter campaigns should emphasize that cigarette butts are not just litter but are toxic

  7. Extending juvenility in grasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaeppler, Shawn; de Leon Gatti, Natalia; Foerster, Jillian

    2017-04-11

    The present invention relates to compositions and methods for modulating the juvenile to adult developmental growth transition in plants, such as grasses (e.g. maize). In particular, the invention provides methods for enhancing agronomic properties in plants by modulating expression of GRMZM2G362718, GRMZM2G096016, or homologs thereof. Modulation of expression of one or more additional genes which affect juvenile to adult developmental growth transition such as Glossy15 or Cg1, in conjunction with such modulation of expression is also contemplated. Nucleic acid constructs for down-regulation of GRMZM2G362718 and/or GRMZM2G096016 are also contemplated, as are transgenic plants and products produced there from, that demonstrate altered, such as extended juvenile growth, and display associated phenotypes such as enhanced yield, improved digestibility, and increased disease resistance. Plants described herein may be used, for example, as improved forage or feed crops or in biofuel production.

  8. Interaction of initial litter quality and thinning intensity on litter decomposition rate, nitrogen accumulation and release in a pine plantation

    Science.gov (United States)

    Xiao Chen; Deborah Page-Dumroese; Ruiheng Lv; Weiwei Wang; Guolei Li; Yong. Liu

    2014-01-01

    Thinning alters litter quality and microclimate under forests. Both of these two changes after thinning induce alterations of litter decomposition rates and nutrient cycling. However, a possible interaction between these two changes remains unclear. We placed two types of litter (LN, low N concentration litter; HN, high N concentration litter) in a Chinese pine (Pinus...

  9. Breeding for Grass Seed Yield

    DEFF Research Database (Denmark)

    Boelt, Birte; Studer, Bruno

    2010-01-01

    Seed yield is a trait of major interest for many fodder and amenity grass species and has received increasing attention since seed multiplication is economically relevant for novel grass cultivars to compete in the commercial market. Although seed yield is a complex trait and affected...... important aspects and components affecting the seed yield potential and the agronomic and environmental aspects affecting the utilization and realization of the seed yield potential. Finally, it discusses the potential of plant breeding to sustainably improve total seed yield in fodder and amenity grasses....

  10. Grass fungal endophytes and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Craven, Kelly

    2015-03-10

    The invention provides isolated fungal endophytes and synthetic combinations thereof with host grass plants. Methods for inoculating grass plant with the endophytes, for propagating the grass-endophyte combinations, and for producing feeds and biofuels from grass-endophyte combinations are also provided.

  11. Leaf litter mixtures alter microbial community development: mechanisms for non-additive effects in litter decomposition.

    Directory of Open Access Journals (Sweden)

    Samantha K Chapman

    Full Text Available To what extent microbial community composition can explain variability in ecosystem processes remains an open question in ecology. Microbial decomposer communities can change during litter decomposition due to biotic interactions and shifting substrate availability. Though relative abundance of decomposers may change due to mixing leaf litter, linking these shifts to the non-additive patterns often recorded in mixed species litter decomposition rates has been elusive, and links community composition to ecosystem function. We extracted phospholipid fatty acids (PLFAs from single species and mixed species leaf litterbags after 10 and 27 months of decomposition in a mixed conifer forest. Total PLFA concentrations were 70% higher on litter mixtures than single litter types after 10 months, but were only 20% higher after 27 months. Similarly, fungal-to-bacterial ratios differed between mixed and single litter types after 10 months of decomposition, but equalized over time. Microbial community composition, as indicated by principal components analyses, differed due to both litter mixing and stage of litter decomposition. PLFA biomarkers a15∶0 and cy17∶0, which indicate gram-positive and gram-negative bacteria respectively, in particular drove these shifts. Total PLFA correlated significantly with single litter mass loss early in decomposition but not at later stages. We conclude that litter mixing alters microbial community development, which can contribute to synergisms in litter decomposition. These findings advance our understanding of how changing forest biodiversity can alter microbial communities and the ecosystem processes they mediate.

  12. Characterization of Forest Structure and an Assessment of Litter ...

    African Journals Online (AJOL)

    Characterization of Forest Structure and an Assessment of Litter Production, Accumulation and Litter-asscociated Invertebrates in Two Naturally Occuring Rhizophora mucronata Stands in Mauritius (Indian Ocean)

  13. Early stage litter decomposition across biomes

    Science.gov (United States)

    Ika Djukic; Sebastian Kepfer-Rojas; Inger Kappel Schmidt; Klaus Steenberg Larsen; Claus Beier; Björn Berg; Kris Verheyen; Adriano Caliman; Alain Paquette; Alba Gutiérrez-Girón; Alberto Humber; Alejandro Valdecantos; Alessandro Petraglia; Heather Alexander; Algirdas Augustaitis; Amélie Saillard; Ana Carolina Ruiz Fernández; Ana I. Sousa; Ana I. Lillebø; Anderson da Rocha Gripp; André-Jean Francez; Andrea Fischer; Andreas Bohner; Andrey Malyshev; Andrijana Andrić; Andy Smith; Angela Stanisci; Anikó Seres; Anja Schmidt; Anna Avila; Anne Probst; Annie Ouin; Anzar A. Khuroo; Arne Verstraeten; Arely N. Palabral-Aguilera; Artur Stefanski; Aurora Gaxiola; Bart Muys; Bernard Bosman; Bernd Ahrends; Bill Parker; Birgit Sattler; Bo Yang; Bohdan Juráni; Brigitta Erschbamer; Carmen Eugenia Rodriguez Ortiz; Casper T. Christiansen; E. Carol Adair; Céline Meredieu; Cendrine Mony; Charles A. Nock; Chi-Ling Chen; Chiao-Ping Wang; Christel Baum; Christian Rixen; Christine Delire; Christophe Piscart; Christopher Andrews; Corinna Rebmann; Cristina Branquinho; Dana Polyanskaya; David Fuentes Delgado; Dirk Wundram; Diyaa Radeideh; Eduardo Ordóñez-Regil; Edward Crawford; Elena Preda; Elena Tropina; Elli Groner; Eric Lucot; Erzsébet Hornung; Esperança Gacia; Esther Lévesque; Evanilde Benedito; Evgeny A. Davydov; Evy Ampoorter; Fabio Padilha Bolzan; Felipe Varela; Ferdinand Kristöfel; Fernando T. Maestre; Florence Maunoury-Danger; Florian Hofhansl; Florian Kitz; Flurin Sutter; Francisco Cuesta; Francisco de Almeida Lobo; Franco Leandro de Souza; Frank Berninger; Franz Zehetner; Georg Wohlfahrt; George Vourlitis; Geovana Carreño-Rocabado; Gina Arena; Gisele Daiane Pinha; Grizelle González; Guylaine Canut; Hanna Lee; Hans Verbeeck; Harald Auge; Harald Pauli; Hassan Bismarck Nacro; Héctor A. Bahamonde; Heike Feldhaar; Heinke Jäger; Helena C. Serrano; Hélène Verheyden; Helge Bruelheide; Henning Meesenburg; Hermann Jungkunst; Hervé Jactel; Hideaki Shibata; Hiroko Kurokawa; Hugo López Rosas; Hugo L. Rojas Villalobos; Ian Yesilonis; Inara Melece; Inge Van Halder; Inmaculada García Quirós; Isaac Makelele; Issaka Senou; István Fekete; Ivan Mihal; Ivika Ostonen; Jana Borovská; Javier Roales; Jawad Shoqeir; Jean-Christophe Lata; Jean-Paul Theurillat; Jean-Luc Probst; Jess Zimmerman; Jeyanny Vijayanathan; Jianwu Tang; Jill Thompson; Jiří Doležal; Joan-Albert Sanchez-Cabeza; Joël Merlet; Joh Henschel; Johan Neirynck; Johannes Knops; John Loehr; Jonathan von Oppen; Jónína Sigríður Þorláksdóttir; Jörg Löffler; José-Gilberto Cardoso-Mohedano; José-Luis Benito-Alonso; Jose Marcelo Torezan; Joseph C. Morina; Juan J. Jiménez; Juan Dario Quinde; Juha Alatalo; Julia Seeber; Jutta Stadler; Kaie Kriiska; Kalifa Coulibaly; Karibu Fukuzawa; Katalin Szlavecz; Katarína Gerhátová; Kate Lajtha; Kathrin Käppeler; Katie A. Jennings; Katja Tielbörger; Kazuhiko Hoshizaki; Ken Green; Lambiénou Yé; Laryssa Helena Ribeiro Pazianoto; Laura Dienstbach; Laura Williams; Laura Yahdjian; Laurel M. Brigham; Liesbeth van den Brink; Lindsey Rustad; al. et

    2018-01-01

    Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies...

  14. Collecting marine litter during regular fish surveys

    NARCIS (Netherlands)

    Sluis, van der M.T.; Hal, van R.

    2014-01-01

    This report presents the results of the marine litter monitoring on the IBTS survey of 2014 and the BTS survey of 2013. Since 2013 marine litter is collected during the International Bottom Trawl Survey (IBTS) and Dutch Beam Trawl Survey (BTS) following a protocol developed by ICES. The composition

  15. Grass and weed killer poisoning

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002838.htm Grass and weed killer poisoning To use the sharing features on this page, please enable JavaScript. Many weed killers contain dangerous chemicals that are harmful if ...

  16. Impact of an Alien Invasive Shrub on Ecology of Native and Alien Invasive Mosquito Species (Diptera: Culicidae).

    Science.gov (United States)

    Muturi, Ephantus J; Gardner, Allison M; Bara, Jeffrey J

    2015-10-01

    We examined how leaf litter of alien invasive honeysuckle (Lonicera maackii Rupr.) either alone or in combination with leaf litter of one of two native tree species, sugar maple (Acer saccharum Marshall) and northern red oak (Quercus rubra L.), affects the ecology of Culex restuans Theobald, Ochlerotatus triseriatus Say, and Ochlerotatus japonicus Theobald. Experimental mesocosms containing single species litter or a mixture of honeysuckle and one of two native tree species litter were established at South Farms and Trelease Woods study sites in Urbana, IL, and examined for their effect on 1) oviposition site selection by the three mosquito species, and 2) adult production and body size of Oc. triseriatus and Oc. japonicus. There were no significant effects of study site and leaf treatment on Oc. japonicus and Oc. triseriatus oviposition preference and adult production. In contrast, significantly more Cx. restuans eggs rafts were collected at South Farms relative to Trelease Woods and in honeysuckle litter relative to native tree species litter. Significantly larger adult females of Oc. japonicus and Oc. triseriatus were collected at South Farms relative to Trelease Woods and in honeysuckle litter relative to native tree species litter. Combining honeysuckle litter with native tree species litter had additive effects on Cx. restuans oviposition preference and Oc. japonicus and Oc. triseriatus body size, with the exception of honeysuckle and northern red oak litter combination, which had antagonistic effects on Oc. triseriatus body size. We conclude that input of honeysuckle litter into container aquatic habitats may alter the life history traits of vector mosquito species. © 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.

  17. The effects of leaf litter nutrient pulses on Alliaria petiolata performance

    Directory of Open Access Journals (Sweden)

    Robert W. Heckman

    2015-08-01

    Full Text Available Nutrient pulses can facilitate species establishment and spread in new habitats, particularly when one species more effectively uses that nutrient pulse. Biological differences in nutrient acquisition between native and exotic species may facilitate invasions into a variety of habitats including deciduous forest understories. Alliaria petiolata (Bieb. Cavara & Grande is an important invader of deciduous forest understories throughout much of North America. These understory communities contain many species which perform the majority of their growth and reproduction before canopy closure in spring. Because A. petiolata is a wintergreen biennial that can be active during autumn and winter, it may utilize nutrients released from decaying leaf litter before its competitors. To investigate this we manipulated the timing of leaf litter addition (fall or spring and experimentally simulated the nutrient pulse from decaying leaves using artificial fertilizer. To determine whether A. petiolata affected the abundance of understory competitors, we also removed A. petiolata from one treatment. A. petiolata that received early nutrients exhibited greater growth. Treatments receiving fall leaf litter or artificial nutrients had greater A. petiolata adult biomass than plots receiving spring nutrient additions (leaf litter or artificial nutrients. However, fall leaf litter addition had no effect on the richness of competitor species. Thus, wintergreen phenology may contribute to the spread of A. petiolata through deciduous forest understories, but may not explain community-level impacts of A. petiolata in deciduous forests.

  18. Study on hydrological functions of litter layers in North China.

    Science.gov (United States)

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2013-01-01

    Canopy interception, throughfall, stemflow, and runoff have received considerable attention during the study of water balance and hydrological processes in forested ecosystems. Past research has either neglected or underestimated the role of hydrological functions of litter layers, although some studies have considered the impact of various characteristics of rainfall and litter on litter interception. Based on both simulated rainfall and litter conditions in North China, the effect of litter mass, rainfall intensity and litter type on the maximum water storage capacity of litter (S) and litter interception storage capacity (C) were investigated under five simulated rainfall intensities and four litter masses for two litter types. The results indicated: 1) the S values increased linearly with litter mass, and the S values of broadleaf litter were on average 2.65 times larger than the S values of needle leaf litter; 2) rainfall intensity rather than litter mass determined the maximum interception storage capacity (Cmax ); Cmax increased linearly with increasing rainfall intensity; by contrast, the minimum interception storage capacity (Cmin ) showed a linear relationship with litter mass, but a poor correlation with rainfall intensity; 3) litter type impacted Cmax and Cmin ; the values of Cmax and Cmin for broadleaf litter were larger than those of needle leaf litter, which indicated that broadleaf litter could intercepte and store more water than needle leaf litter; 4) a gap existed between Cmax and Cmin , indicating that litter played a significant role by allowing rainwater to infiltrate or to produce runoff rather than intercepting it and allowing it to evaporate after the rainfall event; 5) Cmin was always less than S at the same litter mass, which should be considered in future interception predictions. Vegetation and precipitation characteristics played important roles in hydrological characteristics.

  19. Study on hydrological functions of litter layers in North China.

    Directory of Open Access Journals (Sweden)

    Xiang Li

    Full Text Available Canopy interception, throughfall, stemflow, and runoff have received considerable attention during the study of water balance and hydrological processes in forested ecosystems. Past research has either neglected or underestimated the role of hydrological functions of litter layers, although some studies have considered the impact of various characteristics of rainfall and litter on litter interception. Based on both simulated rainfall and litter conditions in North China, the effect of litter mass, rainfall intensity and litter type on the maximum water storage capacity of litter (S and litter interception storage capacity (C were investigated under five simulated rainfall intensities and four litter masses for two litter types. The results indicated: 1 the S values increased linearly with litter mass, and the S values of broadleaf litter were on average 2.65 times larger than the S values of needle leaf litter; 2 rainfall intensity rather than litter mass determined the maximum interception storage capacity (Cmax ; Cmax increased linearly with increasing rainfall intensity; by contrast, the minimum interception storage capacity (Cmin showed a linear relationship with litter mass, but a poor correlation with rainfall intensity; 3 litter type impacted Cmax and Cmin ; the values of Cmax and Cmin for broadleaf litter were larger than those of needle leaf litter, which indicated that broadleaf litter could intercepte and store more water than needle leaf litter; 4 a gap existed between Cmax and Cmin , indicating that litter played a significant role by allowing rainwater to infiltrate or to produce runoff rather than intercepting it and allowing it to evaporate after the rainfall event; 5 Cmin was always less than S at the same litter mass, which should be considered in future interception predictions. Vegetation and precipitation characteristics played important roles in hydrological characteristics.

  20. Skin interface pressure on the NATO litter.

    Science.gov (United States)

    Bridges, Elizabeth J; Schmelz, Joseph O; Mazer, Stephen

    2003-04-01

    The NATO litter serves as a transport device and hospital bed during all types of operations. Little is known about the skin interface pressure on this litter. The purpose of this study was to determine whether various types of padding on the litter and body position affect the peak skin interface pressure and the total body area exposed to interface pressures above 30 mm Hg at different body areas. Thirty-two subjects participated. A repeated measures design was used. The surface effect was statistically significant for all peak pressure and surface area analyses (repeated-measures analysis of variance, p patients if feasible. Preventive measures (turning, elevating the heels) are still required.

  1. Street Littering in Nigerian Towns: towards a Framework for ...

    African Journals Online (AJOL)

    Nekky Umera

    relationships between personal covariates (age, sex, income, education etc.) and littering habits of subjects (why they littered, what they littered, etc). The difference between means was tested by analysis of variance (ANOVA); and factorial analysis was used to analyse geographical variations in littering habits and the most ...

  2. An Approach to Litter Generation and Littering Practices in a Mexico City Neighborhood

    Directory of Open Access Journals (Sweden)

    Cecilia E. Muñoz-Cadena

    2012-08-01

    Full Text Available Urban litter is generated by human societies everywhere. Some litter is recyclable waste. In this study, the acronym RMSW is used to refer to recyclable municipal solid waste generated in streets. Public attitude towards RMSW generation, generators’ perceptions, and quantification of RMSW in streets were examined in a Mexico City neighborhood, where litter presence causes major environmental problems affecting the population year after year. Interviews with neighborhood residents and item counts were carried out from 2010 to 2011. In all, 58% of interviewees reported generating RMSW at variable frequencies while 42% said they did not generate this kind of waste. Laziness, lack of vigilance by municipal authorities, no litter bins in streets, and imitation were the main causes identified by interviewees as reasons for littering. Potential litter generators may be of any age, educational level or income. Interviewees’ perception of RMSW generation was compared with item counts in the neighborhood studied.

  3. Can't See the Wood for the Litter: Evaluation of Litter Behavior Modification in a Forest

    Science.gov (United States)

    Lindemann-Matthies, Petra; Bonigk, Isabel; Benkowitz, Dorothee

    2012-01-01

    This study investigated elementary school children's (n = 171) litter behavior during guided forest tours following two different treatments. Four classes received a verbal appeal not to litter in the forest, while another four classes received both a verbal appeal and a demonstration of the desired litter behavior (picking up litter, putting it…

  4. PERFORMANCE, CARCASS YIELD AND LITTER QUALITY OF BROILERS RAISED ON LITTERS TREATED WITH MICRO-ORGANISMS

    Directory of Open Access Journals (Sweden)

    Dayane Prado da Cruz

    2013-03-01

    Full Text Available The present paper aimed at evaluating the effect of adding beneficial micro-organisms to the litters on litter quality, performance and carcass yield for broilers. A total of 240 one-day chicks were used, and randomly distributed in blocks with four treatments and four replications. The following treatments were carried out in the housing: Treatment 1 – Control with weekly spraying of water on the litters; Treatment 2 – Litter treated with a mixture of inoculated and fermented meal by micro-organisms and weekly spraying of water; Treatment 3 – Litter treated by weekly spraying of micro-organisms; Treatment 4 – Litter treated with the same mixture of meals from treatment two and weekly spraying of micro-organisms. Performance was evaluated by the feed consumption, weight gain, feed conversion, viability and carcass, breast and leg yield. From litter samples, pH, dry matter, ashes and nitrogen were evaluated. No differences were found among the treatments. In the conditions the animals were raised, it can be concluded that the treatment on the litter does not affect performance, carcass yield and quality of the litter for broilers.

  5. Molecular Evolution of Grass Stomata.

    Science.gov (United States)

    Chen, Zhong-Hua; Chen, Guang; Dai, Fei; Wang, Yizhou; Hills, Adrian; Ruan, Yong-Ling; Zhang, Guoping; Franks, Peter J; Nevo, Eviatar; Blatt, Michael R

    2017-02-01

    Grasses began to diversify in the late Cretaceous Period and now dominate more than one third of global land area, including three-quarters of agricultural land. We hypothesize that their success is likely attributed to the evolution of highly responsive stomata capable of maximizing productivity in rapidly changing environments. Grass stomata harness the active turgor control mechanisms present in stomata of more ancient plant lineages, maximizing several morphological and developmental features to ensure rapid responses to environmental inputs. The evolutionary development of grass stomata appears to have been a gradual progression. Therefore, understanding the complex structures, developmental events, regulatory networks, and combinations of ion transporters necessary to drive rapid stomatal movement may inform future efforts towards breeding new crop varieties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Arst on patsiendi poolel / Galina Litter

    Index Scriptorium Estoniae

    Litter, Galina, 1956-

    2006-01-01

    Naistearst Galina Litter seadusest, mis lubab alaealistel ilma vanema nõusolekuta aborti teha. Vastus artiklile : Varro Vooglaid. Vanemate vastutus - kas reaalne või paljasõnaline? // Õpetajate Leht (2006) 13. okt., lk. 1, 7

  7. The importance of an invasive tree fruit as a resource for mosquito larvae.

    Science.gov (United States)

    Reiskind, Michael H; Zarrabi, Ali A

    2011-06-01

    Invasive plants are common and may provide resources through litter for container mosquito larvae. Invasive plant reproductive parts can make up a substantial part of litter but have mostly been ignored as a resource for mosquito larvae. We hypothesized that the reproductive fruits of the invasive eastern red cedar, Juniperus virginiana, provide high quality resources for the invasive, container mosquito Aedes albopictus at the western margin of its invasive range in North America. To test this hypothesis, we performed two laboratory experiments. The first examined the response of individual larvae of Ae. albopictus to different amounts of J. virginiana leaf (fresh and senesced) and J. virginiana fruit (ripe and unripe), as well as to a control leaf (Quercus virginiana, live oak). The second experiment examined the response of different densities of Ae. albopictus larvae to each litter type. We found significant differences in response by individual larvae to different amounts of litter and litter types. We also found J. virginiana litter components could support positive population growth rates as a function of initial larval density where the control leaf could not. We conclude that invasive plants may provide high quality resources, and that the reproductive parts (fruits, flowers, cones) may be an important and overlooked component in provisioning larval habitats. Therefore, the expansion of J. virginiana into grassland areas may contribute to the expansion of Ae. albopictus westward in North America. © 2011 The Society for Vector Ecology.

  8. Water relations of native and introduced C4grasses in a neotropical savanna.

    Science.gov (United States)

    Baruch, Zdravko; Fernández, Denny S

    1993-11-01

    Introduced African grasses are invading Neotropical savannas and displacing the native herbaceous community. This work, which is part of a program to understand the success of the African grasses, specifically investigates whether introduced and native grasses differ in their water relations. The water relations of the native Trachypogon plumosus and the successful invader Hyparrhenia rufa were studied in the field during two consecutive years in the seasonal savannas of Venezuela. The two C 4 grasses differed clearly in their responses to water stress. H. rufa consistently had higher stomatal conductance, transpiration rate, leaf water and osmotic potential and osmotic adjustment than the native T. plumosus. Also, leaf senescence occurred much earlier during the dry season in H. rufa. Both grasses showed a combination of water stress evasion and tolerance mechanisms such as stomatal sensitivity to atmospheric or soil water stress, decreased transpiring area and osmotic adjustment. Evasion mechanisms are more conspicuous in H. rufa whereas T. plumosus is more drought tolerant and uses water more "conservatively". The evasion mechanisms and oportunistic use of water by H. rufa, characteristic of invading species, contribute to, but only partially explain, the success of this grass in the Neotropical savannas where it displaces native plants from sites with better water and nutrient status. Conversely, the higher water stress tolerance of t. plumosus is consistent with its capacity to resist invasion by alien grasses on shallow soils and sites with poorer nutrient and water status.

  9. Effect of the litter material on drinking water quality in broiler production

    Directory of Open Access Journals (Sweden)

    RG Garcia

    2010-09-01

    Full Text Available Considering the importance of drinking water and its effect on broiler performance, drinking water quality was studied using six different litter materials. The presence of coliform bacteria and Escherichia coli was investigated. The following litter materials were used in the trial: wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum, 50% sugarcane bagasse (Saccharum L. + 50% wood shavings, 50% sugarcane bagasse (Saccharum L. + 50% rice husks, and plain sugarcane bagasse (Saccharum L.. A number of 1620 Ross® one-day-old chicks were reared in 54 pens measuring 4.5 m² each, equipped with a bell drinker and a tube feeder. Water samples were collected in sterile tubes on days 28 and 42 of the rearing period, and submitted to the laboratory for analyses. Microbiological data were organized by classes expressed in a logarithm scale, where the lowest contamination corresponds to class 1 and the highest contamination to class 4. Results showed that total coliform contamination was higher on day 28 than in the end of the rearing period, and that E. coli presence was detected during both analyzed periods. The litter materials that presented lower degree of water contamination, predominantly class 1, were sugarcane bagasse and 50% of sugarcane bagasse and 50% of rice husks.

  10. Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

    Science.gov (United States)

    Henry, B. A.; Schade, J. D.; Foreman, K.

    2015-12-01

    Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

  11. Performance of beef steers on Smuts finger grass and Nile grass ...

    African Journals Online (AJOL)

    Literature where animal performance is quantified for. Smuts finger grass and Nile grass pastures in South Africa is limited. In some trials, animal performance on Smuts finger grass and/or Nile grass was reported (Rhind & Goodenough,. 1979, Dannhauser, 1982 Grunow, et al., 1984). The ADG achieved by .steers on Smuts ...

  12. Impact of native grasses and cheatgrass (Bromus tectorum) on Great Basin forb seedling growth

    Science.gov (United States)

    Hilary Parkinson; Cathy Zabinski; Nancy Shaw

    2013-01-01

    Re-establishing native communities that resist exotic weed invasion and provide diverse habitat for wildlife are high priorities for restoration in sagebrush ecosystems. Native forbs are an important component of healthy rangelands in this system, but they are rarely included in seedings. Understanding competitive interactions between forb and grass seedlings is...

  13. Native species regeneration following ungulate exclusion and nonnative grass removal in a remnant Hawaiian dry forest

    Science.gov (United States)

    Jarrod M. Thaxton; T. Colleen Cole; Susan Cordell; Robert J. Cabin; Darren R. Sandquist; Creighton M. Litton

    2010-01-01

    Hawaiian lowland dry forests have been reduced by >90% since first human contact. Restoration has focused on protection from fire and ungulates, and removal of invasive grasses as ways to stimulate native forest regeneration. Despite these efforts, natural regeneration of native plants has been infrequent. To assess effects of previous restoration treatments on...

  14. Returning succession to downy brome dominated rangelands: roadblocks to perennial grass establishment

    Science.gov (United States)

    The most common cause of successional retrogression in the Great Basin is wildfires fueled by downy brome (Bromus tectorum). Downy brome invasion has reduced fire intervals from an estimated 60-100 years down to 5-10 years. Our previous research found that establishment of long-lived perennial grass...

  15. Allergenicity and crossreactivity of buffalo grass ( Stenotaphrum ...

    African Journals Online (AJOL)

    Background. In the subtropical climate of South Africa, grasses of the subfamily Panicoideae are predominant. Bermuda grass has previously been shown to be an important local allergen, and immunoglobulin E (IgE) epitopes of Bermuda grass extracts are known to be distinct from those of the Pooid pollen extracts.

  16. Salisapiliaceae – a new family of oomycetes from marsh grass litter of southeastern North America

    NARCIS (Netherlands)

    Hulvey, J.; Telle, S.; Nigrelli, L.; Lamour, K.; Thines, M.

    2010-01-01

    Leptographium spp. are anamorphs of Grosmannia residing in the order Ophiostomatales. These fungi are typically associated with bark-beetles and are common causal agents of sapstain in lumber and some are important tree pathogens. In this study, Leptographium spp. associated with bark beetles

  17. The effect of lignin photodegradation on decomposability of Calamagrostis epigeios grass litter

    Czech Academy of Sciences Publication Activity Database

    Frouz, J.; Cajthaml, Tomáš; Mudrák, Ondřej

    2011-01-01

    Roč. 22, č. 6 (2011), s. 1247-1254 ISSN 0923-9820 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z60660521 Keywords : Thermochemolysis-GC-MS * (13)C NMR * Decomposition Subject RIV: EE - Microbiology, Virology Impact factor: 2.017, year: 2011

  18. Microbiological Safety of Chicken Litter or Chicken Litter-Based Organic Fertilizers: A Review

    Directory of Open Access Journals (Sweden)

    Zhao Chen

    2014-01-01

    Full Text Available Chicken litter or chicken litter-based organic fertilizers are usually recycled into the soil to improve the structure and fertility of agricultural land. As an important source of nutrients for crop production, chicken litter may also contain a variety of human pathogens that can threaten humans who consume the contaminated food or water. Composting can inactivate pathogens while creating a soil amendment beneficial for application to arable agricultural land. Some foodborne pathogens may have the potential to survive for long periods of time in raw chicken litter or its composted products after land application, and a small population of pathogenic cells may even regrow to high levels when the conditions are favorable for growth. Thermal processing is a good choice for inactivating pathogens in chicken litter or chicken litter-based organic fertilizers prior to land application. However, some populations may become acclimatized to a hostile environment during build-up or composting and develop heat resistance through cross-protection during subsequent high temperature treatment. Therefore, this paper reviews currently available information on the microbiological safety of chicken litter or chicken litter-based organic fertilizers, and discusses about further research on developing novel and effective disinfection techniques, including physical, chemical, and biological treatments, as an alternative to current methods.

  19. Temperatures below leaf litter during winter prescribed burns: implications for litter-roosting bats

    Science.gov (United States)

    Roger W. Perry; Virginia L. McDaniel

    2015-01-01

    Some bat species, including eastern red bats (Lasiurus borealis), roost for short periods beneath leaf litter on the forest floor during winter in the south-eastern USA, a region subjected to frequent fire. The variability in fuel consumption, the heterogeneous nature of burns, and the effects of litter and duff moisture on forest-floor...

  20. Analysis of litter size and average litter weight in pigs using a recursive model

    DEFF Research Database (Denmark)

    Varona, Luis; Sorensen, Daniel; Thompson, Robin

    2007-01-01

    An analysis of litter size and average piglet weight at birth in Landrace and Yorkshire using a standard two-trait mixed model (SMM) and a recursive mixed model (RMM) is presented. The RMM establishes a one-way link from litter size to average piglet weight. It is shown that there is a one-to-one...

  1. Potential energy expenditure by litter-roosting bats associated with temperature under leaf litter during winter

    Science.gov (United States)

    Roger W. Perry

    2013-01-01

    In temperate portions of North America, some bats that remain active during winter undergo short periods of hibernation below leaf litter on the forest floor during episodes of below-freezing weather. These winter roosts may provide above-freezing conditions, but the thermal conditions under leaf litter are unclear. Further, little is known of the relationship between...

  2. Litter NSV; marine litter monitoring by northern fulmars (a pilot study)

    NARCIS (Netherlands)

    Franeker, van J.A.; Meijboom, A.

    2002-01-01

    The northern fulmar is a seabird known to consume litter such as plastic. The Dutch government has asked for an investigation of the possibility to use stomach contents of beach-washed fulmars as a monitoring tool for the abundance of marine litter inthe North Sea. Such monitoring is of importance

  3. Watching eyes on potential litter can reduce littering: evidence from two field experiments

    Directory of Open Access Journals (Sweden)

    Melissa Bateson

    2015-12-01

    Full Text Available Littering constitutes a major societal problem, and any simple intervention that reduces its prevalence would be widely beneficial. In previous research, we have found that displaying images of watching eyes in the environment makes people less likely to litter. Here, we investigate whether the watching eyes images can be transferred onto the potential items of litter themselves. In two field experiments on a university campus, we created an opportunity to litter by attaching leaflets that either did or did not feature an image of watching eyes to parked bicycles. In both experiments, the watching eyes leaflets were substantially less likely to be littered than control leaflets (odds ratios 0.22–0.32. We also found that people were less likely to litter when there other people in the immediate vicinity than when there were not (odds ratios 0.04–0.25 and, in one experiment but not the other, that eye leaflets only reduced littering when there no other people in the immediate vicinity. We suggest that designing cues of observation into packaging could be a simple but fruitful strategy for reducing littering.

  4. Watching eyes on potential litter can reduce littering: evidence from two field experiments.

    Science.gov (United States)

    Bateson, Melissa; Robinson, Rebecca; Abayomi-Cole, Tim; Greenlees, Josh; O'Connor, Abby; Nettle, Daniel

    2015-01-01

    Littering constitutes a major societal problem, and any simple intervention that reduces its prevalence would be widely beneficial. In previous research, we have found that displaying images of watching eyes in the environment makes people less likely to litter. Here, we investigate whether the watching eyes images can be transferred onto the potential items of litter themselves. In two field experiments on a university campus, we created an opportunity to litter by attaching leaflets that either did or did not feature an image of watching eyes to parked bicycles. In both experiments, the watching eyes leaflets were substantially less likely to be littered than control leaflets (odds ratios 0.22-0.32). We also found that people were less likely to litter when there other people in the immediate vicinity than when there were not (odds ratios 0.04-0.25) and, in one experiment but not the other, that eye leaflets only reduced littering when there no other people in the immediate vicinity. We suggest that designing cues of observation into packaging could be a simple but fruitful strategy for reducing littering.

  5. Effects of forest structure on litter production, soil chemical composition and litter-soil interactions

    Directory of Open Access Journals (Sweden)

    Elivane Salete Capellesso

    2016-01-01

    Full Text Available ABSTRACT Litter production in forest ecosystems is a major indicator of primary productivity because litter helps incorporate carbon and nutrients from plants into the soil and is directly involved in plant-soil interactions. To our knowledge, few studies have investigated the relationship between species diversity and ecosystem processes in subtropical forest fragments. In this work, we determined forest structural parameters and assessed seasonal leaf litter input, leaf decomposition rate, litter quality and soil characteristics in two subtropical Atlantic Forest fragments. Litter production was greater in the native fragment with the higher species diversity (FN1. The two native fragments (FN1 and FN2 differed in basal area, volume and dominance in the upper stratum, which were positively correlated with litter production in FN1 but negatively correlated in FN2. Soil in FN1 exhibited higher contents of organic C, available phosphorus and exchangeable calcium, and the leaf litter had a higher C:N ratio. Although these results are consistent with a plant-soil feedback, which suggests the presence of a complementary effect, the dominance of certain families in subtropical forest fragments results in a selection effect on litter productivity and decomposition.

  6. Quality of poultry litter submitted to different treatments in five consecutive flocks Qualidade da cama de frango submetida a diferentes tratamentos em cinco lotes consecutivos

    Directory of Open Access Journals (Sweden)

    Fernando Carlos Loch

    2011-05-01

    Full Text Available It was evaluated the effects of poultry litter treatment on moisture content, pH, density and volatilized ammonia for five consecutive flocks of broiler chicken breeding. It was used 640 birds per flock as a complete randomized design with eight treatments and four replicates. The treatments were the following: 1 non-treated litter; 2 litter submitted to in-house composting; 3 litter treated with aluminum sulfate; 4 litter submitted to gypsum; 5 litter treated with quicklime; 6 litter treated with dolomitic limestone; 7 litter treated with zeolite and 8 litter treated with charcoal. Chopped elephant-grass hay was used as poultry litter in all flocks. Fermentation in the shed increased moisture content of the litters in the second and first flocks on 21 and 42 days of breeding, respectively. There was no difference on density among treatments. Aluminum sulfate reduced pH of the litters in all flocks at 21 days of breding. On 42 days of breeding, pH of the litters was reduced in the litters with aluminum sulfate and gypsum in the first, second and forth flocks. On 21 days, aluminum sulfate reduced the volatilized ammonia in the first, third and forth flocks, and on 42 days, there was a reduction of volatilized ammonia in the litters with aluminum sulfate in the forth flock. Aluminum sulfate can improve quality of poultry litter of chopped elephant-grass hay by reducing pH and ammonia volatilization.Foram avaliados os efeitos do tratamento da cama de frango sobre o teor de umidade, o pH, a densidade e a amônia volatilizada durante cinco lotes consecutivos de criação de frangos de corte. Foram utilizadas 640 aves por lote em delineamento inteiramente casualizado com oito tratamentos e quatro repetições. Os tratamentos foram: 1 cama não-tratada; 2 cama submetida à compostagem dentro do galpão; 3 cama tratada com sulfato de alumínio; 4 cama tratada com gesso agrícola; 5 cama tratada com cal virgem; 6 cama tratada com calcário dolomítico; 7

  7. The Effect of Litter Position on Ultraviolet Photodegradation of Standing Dead Litter

    Science.gov (United States)

    Lin, Y.; King, J. Y.

    2012-12-01

    In dryland ecosystems, models incorporating only biotic mechanisms usually underestimate the decay rate of plant litter. Photodegradation, an abiotic process through which solar radiation breaks down organic matter, has recently been proposed as an important pathway of litter decomposition in dryland ecosystems, accounting for as much as 25 to 60% of mass loss. However, it remains unclear what factors control the relative importance of photodegradation and biotic decomposition. It is hypothesized that this balance is affected by the location of litter within the litter layer (or thatch): in upper layers of thatch, photodegradation is significant because litter is exposed to sunlight; in lower layers where litter is strongly shaded, photodegradation is negligible compared to biotic decomposition. In August 2011, a field experiment was initiated at the University of California's Sedgwick Reserve, Santa Ynez, CA, in order to understand how ultraviolet (UV) radiation and litter position within the thatch affect litter decomposition. Two levels of UV radiation (280-400 nm) are achieved by screens: "UV-Pass" (transmitting > 81% of UV radiation) and "UV-Block" (transmitting plant litter was 19% higher in UV-Pass than in UV-Block treatments, but there was no difference at the top of the thatch. Because lignin is recalcitrant to biotic decomposition, a greater proportion of lignin could remain in litter where biotic decomposition was faster. Therefore, the pattern of lignin concentration supports the interpretation that greater biotic decomposition occurred under the UV-Pass treatment. Regardless of UV manipulation, litter mass loss was 25% faster at the top of the thatch than at the bottom. Litter at the top of the thatch also had 6% higher cellulose concentration and 13% lower lignin concentration than at the bottom of the thatch after 9 months of field exposure. Photodegradation (by UV and visible light) likely contributed more to decomposition at the top of the thatch

  8. Effect of temperature on seed production in the invasive grass ...

    African Journals Online (AJOL)

    Temperature is one of the main factors that determine sexual reproduction in terrestrial and emergent aquatic plant species. The effect of temperature on sexual reproduction and seed production of Glyceria maxima (Hartm.) Holmb. in the southern hemisphere is unknown. Glyceria maxima collections in February 2010 at ...

  9. Decomposition of standing litter in arid grasslands: Interactions between sunlight, non-rainfall moisture, microbes, and plant traits

    Science.gov (United States)

    Logan, J. R. V.; Jacobson, P. J.; Jacobson, K. M.; Evans, S.

    2017-12-01

    Although arid lands make up 40% of the Earth's land surface, we still lack a strong understanding of carbon cycling and plant decomposition in these systems. One reason for this is that field studies typically only focus on decomposition at or below the ground surface even though standing dead litter (material that has not yet fallen to the ground) accounts for more than 50% of total necromass in many of these systems. While recent work has begun to recognize the important and unique aspects of standing litter decomposition, few studies have investigated specific mechanisms controlling rates of mass loss. We hypothesized that initial photodegradation of the outer plant cuticle of standing litter is an important determinant of litter decomposition because this process increases moisture absorption and subsequent opportunities for biological decomposition. Our preliminary results offer support for this hypothesis. We found that standing grass stems with their cuticles artificially removed had greater water absorbance and more than 400% greater mass loss over a 6-month period relative to controls with intact cuticles. Additionally, spectroscopic measurements of cuticle integrity showed damage to the litter surface after a period of extended photodegradation, allowing increased moisture uptake during simulated fog/dew events. These findings are especially important in the context of recent work by us and others showing that non-rainfall moisture (fog, dew, and water vapor) plays a much larger role in arid land decomposition than previously thought. Improving our understanding of the mechanisms driving decomposition of standing litter will enable us to develop a more predictive understanding of carbon storage in arid lands.

  10. First direct confirmation of grass carp spawning in a Great Lakes tributary

    Science.gov (United States)

    Embke, Holly S.; Kocovsky, Patrick M.; Richter, Catherine A.; Pritt, Jeremy J.; Christine M. Mayer,; Qian, Song

    2016-01-01

    Grass carp (Ctenopharyngodon idella), an invasive species of Asian carp, has been stocked for many decades in the United States for vegetation control. Adult individuals have been found in all of the Great Lakes except Lake Superior, but no self-sustaining populations have yet been identified in Great Lakes tributaries. In 2012, a commercial fisherman caught four juvenile diploid grass carp in the Sandusky River, a major tributary to Lake Erie. Otolith microchemistry and the capture location of these fish permitted the conclusion that they were most likely produced in the Sandusky River. Due to this finding, we sampled ichthyoplankton using paired bongo net tows and larval light traps during June–August of 2014 and 2015 to determine if grass carp are spawning in the Sandusky River. From the samples collected in 2015, we identified and staged eight eggs that were morphologically consistent with grass carp. Five eggs were confirmed as grass carp using quantitative Polymerase Chain Reaction for a grass carp-specific marker, while the remaining three were retained for future analysis. Our finding confirms that grass carp are naturally spawning in this Great Lakes tributary. All eggs were collected during high-flow events, either on the day of peak flow or 1–2 days following peak flow, supporting an earlier suggestion that high flow conditions favor grass carp spawning. The next principal goal is to identify the spawning and hatch location(s) for the Sandusky River. Predicting locations and conditions where grass carp spawning is most probable may aid targeted management efforts.

  11. Invasive earthworms interact with abiotic conditions to influence the invasion of common buckthorn (Rhamnus cathartica).

    Science.gov (United States)

    Roth, Alexander M; Whitfeld, Timothy J S; Lodge, Alexandra G; Eisenhauer, Nico; Frelich, Lee E; Reich, Peter B

    2015-05-01

    Common buckthorn (Rhamnus cathartica L.) is one of the most abundant and ecologically harmful non-native plants in forests of the Upper Midwest United States. At the same time, European earthworms are invading previously glaciated areas in this region, with largely anecdotal evidence suggesting they compound the negative effects of buckthorn and influence the invasibility of these forests. Germination and seedling establishment are important control points for colonization by any species, and manipulation of the conditions influencing these life history stages may provide insight into why invasive species are successful in some environments and not others. Using a greenhouse microcosm experiment, we examined the effects of important biotic and abiotic factors on the germination and seedling establishment of common buckthorn. We manipulated light levels, leaf litter depth and earthworm presence to investigate the independent and interactive effects of these treatments on buckthorn establishment. We found that light and leaf litter depth were significant predictors of buckthorn germination but that the presence of earthworms was the most important factor; earthworms interacted with light and leaf litter to increase the number and biomass of buckthorn across all treatments. Path analysis suggested both direct and moisture-mediated indirect mechanisms controlled these processes. The results suggest that the action of earthworms may provide a pathway through which buckthorn invades forests of the Upper Midwest United States. Hence, researchers and managers should consider co-invasion of plants and earthworms when investigating invasibility and creating preemptive or post-invasion management plans.

  12. Impact of Flaveria bidentis Litter on Communities of Invertebrates in Soil in Different Habitats

    Directory of Open Access Journals (Sweden)

    YAN Jing

    2016-03-01

    Full Text Available An investigation was conducted to explore the impacts of Flaveria bidentis litter on the communities of invertebrates in soil in three different habitats including forestland, wasteland, and ditches. A total of 54315 individuals were captured in three habitats on October 23rd by cutting ring(diameter is 20 cm, height is 10 cm, which is divided into three sampling layers in this study. All of the individuals belong to 2 phyla 10 classes 17 orders, among which Arachnoidea and Collembola were the dominant orders in three habitats, and the relative abundance of other species were smaller. F. bidentis litter could provide the better habitats and food sources for invertebrates in soil, such as Arachnoidea, Collembola, Psocoptera and so on, thereby affecting their structure and diversity of community of invertebrates in soil which mainly related to growth conditions of F. bidentis community, which is characterized by its weaker growth conditions in forestland but stronger growth in wasteland land and ditches. In summary, F. bidentis plants and their litter provided habitat and concealment for the dominant species, and significantly changed content of nitrogen, phosphorus, potassium and organic matter in surface humus soil after the invasion of F. bidentis in three habitats, which cause the increasing of diversity of invertebrates in soil and also it trends to increase for the diversity of invertebrates in liter from top to bottom. Thus it laid a foundation for the influence of decomposition rate in F. bidentis litter on the diversity of invertebrate communities in soil.

  13. Competition for soil nitrate and invasive weed resistance of three shrub-steppe growth forms

    Science.gov (United States)

    Eamonn D. Leonard

    2007-01-01

    Determining mechanisms responsible for weed resistance and invasion success are two issues that have potential in aiding successful land management decisions. The first experiment evaluates the competitive effects of an invasive annual grass downy brome (Bromus tectorum L.), an invasive biennial forb dyer's woad (Isatis tinctoria...

  14. Plant invasion phenomenon enhances reproduction performance in an endangered spider

    Science.gov (United States)

    Pétillon, Julien; Puzin, Charlène; Acou, Anthony; Outreman, Yannick

    2009-10-01

    Current models in evolutionary ecology predict life history alterations in response to habitat suitability to optimize fitness. Only few empirical studies have demonstrated how life history traits that are expected to trade off against each other differ among environments. In Europe, many salt marshes have been recently invaded by the grass Elymus athericus. Previous studies however showed higher densities of the endangered spider Arctosa fulvolineata (Araneae: Lycosidae) in invaded salt marshes compared to natural habitats, which suggests a lower habitat suitability in the latter. The aim of this study was to determine if this emerging habitat (1) affects the amount of resource acquisition and (2) alters the balance between life history traits that are expected to trade off against each other in this stenotopic salt marsh species. As suggested by theoretical studies, an optimization of fitness by increasing egg size at the cost of decreasing fecundity in unsuitable (i.e., natural) habitats was expected. Females presenting cocoon were then collected in close invaded and natural salt marsh areas within the Mont Saint-Michel Bay (France). By considering female mass as covariate, cocoon mass, number of eggs, and egg volume were compared between both habitats. Clutch mass was strongly determined by female mass in both habitats. Clutch mass was however significantly smaller in the natural habitat compared to the invaded habitat, indicating a higher resource acquisition in the latter. When correcting for female size, fecundity was additionally increased in the invaded habitat through a significant decrease in egg size. This phenotypic response can be explained by differences in habitat structure between invaded and natural habitats: the former offers a more complex litter favoring nocturnal wanderers like A. fulvolineata. The existence of such an adaptive reproduction strategy depending on habitat suitability constitutes an original case of an invasion that favors an

  15. Long-term differences in annual litter production between alien (Sonneratia apetala) and native (Kandelia obovata) mangrove species in Futian, Shenzhen, China.

    Science.gov (United States)

    Liu, Lina; Li, Fenglan; Yang, Qiong; Tam, Nora F Y; Liao, Wenbo; Zan, Qijie

    2014-08-30

    Annual litter production in alien (Sonneratia apetala) and native (Kandelia obovata) mangrove forests in Shenzhen, China were compared from 1999 to 2010. S. apetala had significantly higher litter production than K. obovata, with mean annual total litter of 18.1 t ha(-1) yr(-1) and 15.2 t ha(-1) yr(-1), respectively. The higher litter production in S. apetala forest indicates higher productivity and consequently more nutrient supply to the estuarine ecosystems but may be more invasive due to positive plant-soil feedbacks and nutrient availability to this alien species. Two peaks were recorded in S. apetala (May and October), while only one peak was observed in K. obovata, in early spring (March and April). Leaf and reproductive materials were the main contributors to litter production (>80%) in both forests. These results suggest that the ecological function of S. apetala and its invasive potential can be better understood based on a long-term litter fall analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. The global stoichiometry of litter nitrogen mineralization.

    Science.gov (United States)

    Manzoni, Stefano; Jackson, Robert B; Trofymow, John A; Porporato, Amilcare

    2008-08-01

    Plant residue decomposition and the nutrient release to the soil play a major role in global carbon and nutrient cycling. Although decomposition rates vary strongly with climate, nitrogen immobilization into litter and its release in mineral forms are mainly controlled by the initial chemical composition of the residues. We used a data set of approximately 2800 observations to show that these global nitrogen-release patterns can be explained by fundamental stoichiometric relationships of decomposer activity. We show how litter quality controls the transition from nitrogen accumulation into the litter to release and alters decomposers' respiration patterns. Our results suggest that decomposers lower their carbon-use efficiency to exploit residues with low initial nitrogen concentration, a strategy used broadly by bacteria and consumers across trophic levels.

  17. Control of climate and litter quality on leaf litter decomposition in different climatic zones.

    Science.gov (United States)

    Zhang, Xinyue; Wang, Wei

    2015-09-01

    Climate and initial litter quality are the major factors influencing decomposition rates on large scales. We established a comprehensive database of terrestrial leaf litter decomposition, including 785 datasets, to examine the relationship between climate and litter quality and evaluate the factors controlling decomposition on a global scale, the arid and semi-arid (AS) zone, the humid middle and humid low (HL) latitude zones. Initial litter nitrogen (N) and phosphorus (P) concentration only increased with mean annual temperature (MAT) in the AS zone and decreased with mean annual precipitation (MAP) in the HL zone. Compared with nutrient content, MAT imposed less effect on initial litter lignin content than MAP. MAT were the most important decomposition driving factors on a global scale as well as in different climatic zones. MAP only significantly affected decomposition constants in AS zone. Although litter quality parameters also showed significant influence on decomposition, their importance was less than the climatic factors. Besides, different litter quality parameters exerted significant influence on decomposition in different climatic zones. Our results emphasized that climate consistently exerted important effects on decomposition constants across different climatic zones.

  18. The relative importance of different grass components in controlling runoff and erosion on a hillslope under simulated rainfall

    Science.gov (United States)

    Li, Changjia; Pan, Chengzhong

    2018-03-01

    The effects of vegetation cover on overland flow and erosion processes on hillslopes vary with vegetation type and spatial distribution and the different vegetation components, including the above- and below-ground biomass. However, few attempts have been made to quantify how these factors affect erosion processes. Field experimental plots (5 m × 2 m) with a slope of approximately 25° were constructed and simulated rainfall (60 mm hr-1) (Rainfall) and simulated rainfall combined with upslope overland flow (20 L min-1) (Rainfall + Flow) were applied. Three grass species were planted, specifically Astragalus adsurgens (A. adsurgens), Medicago sativa (M. sativa) and Cosmos bipinnatus (C. bipinnatus). To isolate and quantify the relative contributions of the above-ground grass parts (stems, litter cover and leaves) and the roots to reducing surface runoff and erosion, each of the three grass species was subjected to three treatments: intact grass control (IG), no litter or leaves (only the grass stems and roots were reserved) (NLL), and only roots remaining (OR). The results showed that planting grass significantly reduced overland flow rate and velocity and sediment yield, and the mean reductions were 21.8%, 29.1% and 67.1%, respectively. M. sativa performed the best in controlling water and soil losses due to its thick canopy and dense, fine roots. Grasses reduced soil erosion mainly during the early stage of overland flow generation. The above-ground grass parts primarily contributed to reducing overland flow rate and velocity, with mean relative contributions of 64% and 86%, respectively. The roots played a predominant role in reducing soil erosion, with mean contribution of 84%. Due to the impact of upslope inflow, overland flow rate and velocity and sediment yield increased under the Rainfall + Flow conditions. The results suggest that grass species on downslope parts of semi-arid hillslopes performed better in reducing water and soil losses. This study is

  19. Litter decomposition and nutrient dynamics of ten selected tree ...

    African Journals Online (AJOL)

    Litter decomposition processes in tropical rainforests are still poorly understood. Leaf litter decomposition and nutrient dynamics of ten contrasting tree species, Entandraphragma utile, Guibourtia tessmannii, Klainedoxa gabonensis, Musanga cecropioides, Panda oleosa, Plagiostyles africana, Pterocarpus soyauxii, ...

  20. The partitioning of litter carbon during litter decomposition under different rainfall patterns: a laboratory study

    Science.gov (United States)

    Yang, X.; Szlavecz, K. A.; Langley, J. A.; Pitz, S.; Chang, C. H.

    2017-12-01

    Quantifying litter C into different C fluxes during litter decomposition is necessary to understand carbon cycling under changing climatic conditions. Rainfall patterns are predicted to change in the future, and their effects on the fate of litter carbon are poorly understood. Soils from deciduous forests in Smithsonian Environmental Research Center (SERC) in Maryland, USA were collected to reconstruct soil columns in the lab. 13C labeled tulip poplar leaf litter was used to trace carbon during litter decomposition. Top 1% and the mean of 15-minute historical precipitation data from nearby weather stations were considered as extreme and control rainfall intensity, respectively. Both intensity and frequency of rainfall were manipulated, while the total amount was kept constant. A pulse of CO2 efflux was detected right after each rainfall event in the soil columns with leaf litter. After the first event, CO2 efflux of the control rainfall treatment soils increased to threefold of the CO2 efflux before rain event and that of the extreme treatment soils increased to fivefold. However, in soils without leaf litter, CO2 efflux was suppressed right after rainfall events. After each rainfall event, the leaf litter contribution to CO2 efflux first showed an increase, decreased sharply in the following two days, and then stayed relatively constant. In soil columns with leaf litter, the order of cumulative CO2 efflux was control > extreme > intermediate. The order of cumulative CO2 efflux in the bare soil treatment was extreme > intermediate > control. The order of volume of leachate from different treatments was extreme > intermediate > control. Our initial results suggest that more intense rainfall events result in larger pulses of CO2, which is rarely measured in the field. Additionally, soils with and without leaf litter respond differently to precipitation events. This is important to consider in temperate regions where leaf litter cover changes throughout the year

  1. Coherent Microwave Scattering Model of Marsh Grass

    Science.gov (United States)

    Duan, Xueyang; Jones, Cathleen E.

    2017-12-01

    In this work, we developed an electromagnetic scattering model to analyze radar scattering from tall-grass-covered lands such as wetlands and marshes. The model adopts the generalized iterative extended boundary condition method (GIEBCM) algorithm, previously developed for buried cylindrical media such as vegetation roots, to simulate the scattering from the grass layer. The major challenge of applying GIEBCM to tall grass is the extremely time-consuming iteration among the large number of short subcylinders building up the grass. To overcome this issue, we extended the GIEBCM to multilevel GIEBCM, or M-GIEBCM, in which we first use GIEBCM to calculate a T matrix (transition matrix) database of "straws" with various lengths, thicknesses, orientations, curvatures, and dielectric properties; we then construct the grass with a group of straws from the database and apply GIEBCM again to calculate the T matrix of the overall grass scene. The grass T matrix is transferred to S matrix (scattering matrix) and combined with the ground S matrix, which is computed using the stabilized extended boundary condition method, to obtain the total scattering. In this article, we will demonstrate the capability of the model by simulating scattering from scenes with different grass densities, different grass structures, different grass water contents, and different ground moisture contents. This model will help with radar experiment design and image interpretation for marshland and wetland observations.

  2. Macro-detritivore identity drives leaf litter diversity effects

    NARCIS (Netherlands)

    Vos, V.C.A.; Ruijven, van J.; Berg, M.P.; Peeters, E.T.H.M.; Berendse, F.

    2011-01-01

    The importance of leaf litter diversity for decomposition, an important process in terrestrial ecosystems, is much debated. Previous leaf litter-mixing studies have shown that non-additive leaf litter diversity effects can occur, but it is not clear why they occurred in only half of the studies and

  3. Current status on marine litter indicators in Nordic waters

    DEFF Research Database (Denmark)

    Strand, Jakob; Tairova, Zhanna; Magnusson, Kerstin

    Status for project on Marine litter in the Nordic waters. This includes a review of Nordic studies on marine litter indicators. Various studies as part of either research or existing monitoring have provided information on occurrence of marine litter in Nordic waters from Baltic Sea to the Arctic....

  4. Precision litter application practices for cotton production and soil properties

    Science.gov (United States)

    Interest in using broiler litter as an important and inexpensive source of plant nutrient has been recognized and many farmers have utilized broiler litter in their nutrient management practices. In recent years poultry producers have turned to pelletization of litter to increase the economic feasib...

  5. Litter fall and decomposition of mangrove species Avicennia marina ...

    African Journals Online (AJOL)

    Abstract—Litter fall and decomposition of mangrove leaves were compared for different seasons, species (Avicennia marina and Rhizophora mucronata) and sites in southern Mozambique. Mangrove leaf litter fall and decomposition was estimated using small mesh collecting-baskets and litter bags respectively in 2006 and ...

  6. Mangrove litter production and seasonality of dominant species in ...

    African Journals Online (AJOL)

    This study is aimed at examining the litter production and seasonality of Avicennia marina, Bruguiera gymnorhiza, and Rhizophora mucronata. Litter was collected using nylon litter traps of 1 mm2 mesh size in the Uzi-Nyeke mixed mangroves, Zanzibar, over a period of 2 years. Contents were sorted, dried, weighed, and the ...

  7. The measurement and reduction of urban litter entering stormwater ...

    African Journals Online (AJOL)

    A previous South African study looked at the removal of litter from the drainage systems once it was already there. Yet the litter problem cannot be addressed in an effective and sustainable manner without an effective integrated catchmentwide litter management strategy. This strategy should include planning controls, ...

  8. Litter decay rates are determined by lignin chemistry

    Science.gov (United States)

    Jennifer M. Talbot; Daniel J. Yelle; James Nowick; Kathleen K. Treseder

    2011-01-01

    Litter decay rates are often correlated with the initial lignin:N or lignin:cellulose content of litter, suggesting that interactions between lignin and more labile compounds are important controls over litter decomposition. The chemical composition of lignin may influence these interactions, if lignin physically or chemically protects labile components from microbial...

  9. Separating duff and litter for improved mass and carbon estimates

    Science.gov (United States)

    David Chojnacky; Michael Amacher; Michael Gavazzi

    2009-01-01

    Mass and carbon load estimates, such as those from forest soil organic matter (duff and litter), inform forestry decisions. The US Forest Inventory and Analysis (FIA) Program systematically collects data nationwide: a down woody material protocol specifies discrete duff and litter depth measurements, and a soils protocol specifies mass and carbon of duff and litter...

  10. Litter for life : assessing the multifunctional legacy of plant traits

    NARCIS (Netherlands)

    Dias, André Tavares Corrêa; Cornelissen, Johannes H.C.; Berg, Matty P.

    2017-01-01

    Litter drives a wide variety of important functions in both terrestrial and aquatic ecosystems. However, the role of litter in regulating community dynamics and ecosystem processes has mostly been studied in terms of litter presence or amount. Besides in biogeochemistry, we still do not know how

  11. ( Rosa damascena Mill.) dreg: an alternative litter material in broiler ...

    African Journals Online (AJOL)

    The present study was carried out to determine the effects of using dried rose dreg (DRD) as an alternative litter material for broiler performance and microbiological characteristics of litter. A total of 225 day-old broiler chicks was raised on pine wood shavings (PS), DRD and PS+DRD until 42 days. The effects of litter ...

  12. Evaluation of within-litter birth weight variation in piglets

    African Journals Online (AJOL)

    VaZindove

    2014-03-23

    Mar 23, 2014 ... Canario, L., Lundgren, H., Haandlykken, M. & Rydhmer, L., 2010. Genetics of growth in piglets and the association with homogeneity of weight within litters. J. Anim. Sci. 88, 1240-1247. Chimonyo, M., Dzama, K. & Bhebhe, E., 2006. Genetic determination of individual birth weight, litter weight and litter size ...

  13. Leaf litter and roots as sources of mineral soil organic matter in temperate deciduous forest with and without earthworms

    Science.gov (United States)

    Fahey, T.; Yavitt, J. B.

    2012-12-01

    We labeled sugar maple trees with 13C to quantify the separate contributions of decaying leaf litter and root turnover/rhizosphere C flux to mineral soil organic matter (SOM). Labeled leaf litter was applied to forest plots with and without earthworms and recovery of the label in SOM was quantified over three years. In parallel, label recovery was quantified in soils from the labeling chambers where all label was supplied by belowground C flux. In the absence of earthworms about half of the label added as leaf litter remained in the surface organic horizons after three years, with about 3% recovered in mineral SOM. The label was most enriched on silt + clay surfaces, representing precipitation of DOC derived from litter. Earthworms mixed nearly all the leaf litter into mineral soil within one year, and after two years the label was most enriched in particulate organic matter held within soil aggregates produced by worms. After three years 15-20% of the added label was recovered in mineral SOM. In the labeling chambers over 75% of belowground C allocation (BCA) was used in root and rhizosphere respiration in the first year after labeling. We recovered only 3.8% of estimated BCA in SOM after 3 years; however, expressed as a proportion of fine root production plus rhizosphere C flux, this value is 15.4%, comparable to that for leaf litter in the presence of earthworms. In conclusion, both roots and leaf litter contribute significantly to the formation of stabilized mineral SOM in temperate deciduous forests, and this process is profoundly altered by the invasion of lumbricid earthworms.

  14. Invasive Species

    Science.gov (United States)

    Invasive species have significantly changed the Great Lakes ecosystem. An invasive species is a plant or animal that is not native to an ecosystem, and whose introduction is likely to cause economic, human health, or environmental damage.

  15. Harvesting Effects on Species Composition and Distribution of Cover Attributes in Mixed Native Warm-Season Grass Stands

    Directory of Open Access Journals (Sweden)

    Vitalis W. Temu

    2015-05-01

    Full Text Available Managing grasslands for forage and ground-nesting bird habitat requires appropriate defoliation strategies. Subsequent early-summer species composition in mixed stands of native warm-season grasses (Indiangrass (IG, Sorghastrum nutans, big bluestem (BB, Andropogon gerardii and little bluestem (LB, Schizachyrium scoparium responding to harvest intervals (treatments, 30, 40, 60, 90 or 120 d and durations (years in production was assessed. Over three years, phased May harvestings were initiated on sets of randomized plots, ≥90 cm apart, in five replications (blocks to produce one-, two- and three-year-old stands. Two weeks after harvest, the frequencies of occurrence of plant species, litter and bare ground, diagonally across each plot (line intercept, were compared. Harvest intervals did not influence proportions of dominant plant species, occurrence of major plant types or litter, but increased that of bare ground patches. Harvest duration increased the occurrence of herbaceous forbs and bare ground patches, decreased that of tall-growing forbs and litter, but without affecting that of perennial grasses, following a year with more September rainfall. Data suggest that one- or two-year full-season forage harvesting may not compromise subsequent breeding habitat for bobwhites and other ground-nesting birds in similar stands. It may take longer than a year’s rest for similar stands to recover from such changes in species composition.

  16. Macroinvertebrate identity mediates the effects of litter quality and microbial conditioning on leaf litter recycling in temperate streams.

    Science.gov (United States)

    Santonja, Mathieu; Pellan, Laura; Piscart, Christophe

    2018-03-01

    Plant litter decomposition is an essential ecosystem function that contributes to carbon and nutrient cycling in streams. Aquatic shredders, mainly macroinvertebrates, can affect this process in various ways; they consume leaf litter, breaking it down into fragments and creating suitable habitats or resources for other organisms through the production of fine particulate organic matter (FPOM). However, measures of litter-feeding traits across a wide range of aquatic macroinvertebrates are still rare. Here, we assessed the contributions of 11 species of freshwater macroinvertebrates to litter decomposition, by measuring consumption rate, FPOM production, and assimilation rate of highly decomposable ( Alnus glutinosa ) or poorly decomposable ( Quercus robur ) leaf litter types. In general, an increase in the quality of litter improved the litter consumption rate, and fungal conditioning of the leaf litter increased both the litter consumption rate and FPOM production. Macroinvertebrates specializing in leaf litter consumption also appeared to be the most sensitive to shifts in litter quality and the conditioning process. Contrary to expectations, the conditioning process did not increase the assimilation of low-quality litter. There was a strong correlation between the relative consumption rate (RCR) of the two litter types, and the relative FPOM production (RFP) was strongly correlated to the RCR. These findings suggest a consistent relationship between RCR and macroinvertebrate identity that is not affected by litter quality, and that the RFP could be inferred from the RCR. The varying responses of the macroinvertebrate feeding traits to litter quality and the conditioning process suggest that the replacement of a shredder invertebrate species by another species could have major consequences for the decomposition process and the detritus-based food web in streams. Further studies onto the importance of invertebrate identity and the effects of litter quality in a

  17. Economic instruments and marine litter control

    NARCIS (Netherlands)

    Oosterhuis, F.H.; Papyrakis, E.; Boteler, B.

    2014-01-01

    This paper provides a comprehensive up-to-date review of the literature on the economic instruments that can reduce marine litter. We assess their cost of implementation, level of effectiveness as well as indirect environmental and socio-economic effects (externalities) that may arise as a result of

  18. Climate history shapes contemporary leaf litter decomposition

    Science.gov (United States)

    Michael S. Strickland; Ashley D. Keiser; Mark A. Bradford

    2015-01-01

    Litter decomposition is mediated by multiple variables, of which climate is expected to be a dominant factor at global scales. However, like other organisms, traits of decomposers and their communities are shaped not just by the contemporary climate but also their climate history. Whether or not this affects decomposition rates is underexplored. Here we source...

  19. Utilization of poultry litter for pesticide bioremediation

    Science.gov (United States)

    Agricultural chemical products such as pesticides have been used to increase crop production, especially in undeveloped countries. Poultry litter, the combination of feces and bedding materials, has also been used as an alternative to improve soil quality for crop production. However, information re...

  20. Treating poultry litter with aluminum sulfate (alum)

    Science.gov (United States)

    This is a USDA/ARS factsheet on how to treat poultry litter with aluminum sulfate (alum) to reduce ammonia emissions. Over half of the nitrogen excreted from chickens is lost to the atmosphere as ammonia before the manure is removed from the poultry houses. Research has shown that additions of alu...

  1. Solutions for global marine litter pollution

    NARCIS (Netherlands)

    Löhr, Ansje; Savelli, Heidi; Beunen, Raoul; Kalz, Marco; Ragas, Ad; Van Belleghem, Frank

    2017-01-01

    Since the 1950s the amount of plastics in the marine environment has increased dramatically. Worldwide there is a growing concern about the risks and possible adverse effects of (micro)plastics. This paper reflects on the sources and effects of marine litter and the effects of policies and other

  2. The global stoichiometry of litter nitrogen mineralization

    Science.gov (United States)

    Stefano Manzoni; Robert B. Jackson; John A. Trofymow; Amilcare Porporato

    2008-01-01

    Plant residue decomposition and the nutrient release to the soil play a major role in global carbon and nutrient cycling. Although decomposition rates vary strongly with climate, nitrogen immobilization into litter and its release in mineral forms are mainly controlled by the initial chemical composition of the residues. We used a data set of ~2800 observations to show...

  3. Ecological restoration of litter in mined areas

    Science.gov (United States)

    Teresinha Gonçalves Bizuti, Denise; Nino Diniz, Najara; Schweizer, Daniella; de Marchi Soares, Thaís; Casagrande, José Carlos; Henrique Santin Brancalion, Pedro

    2016-04-01

    The success of ecological restoration projects depends on going monitoring of key ecological variables to determine if a desired trajectory has been established and, in the case of mining sites, nutrient cycling recovery plays an utmost importance. This study aimed to quantify and compare the annual litter production in native forests, and in restoration sites established in bauxite mines. We collected samples in 6 native forest remnants and 6 year-old restoration sites every month for a period of one year, in the city of Poços de Caldas/MG, SE Brazil. 120 wire collectors were used (0,6x0,6) and suspended 30cm above the soil surface. The material was dried until constant weight, weighed and fractionated in leaves, branches and reproductive material. The average annual litter production was 2,6 Mg ha-1 in native forests and 2,1 in forest in restoration sites, differing statistically. Litter production was higher in the rainy season, especially in September. Among the litter components, the largest contributor to total production was the fraction leaves, with 55,4% of the total dry weight of material collected, followed by reproductive material which contributed 24,5% and branches, with 20%. We conclude that the young areas in restoration process already restored important part, but still below the production observed in native areas.

  4. Leaf litter dynamics and litter consumption in two temperate South Australian mangrove forests

    Science.gov (United States)

    Imgraben, Sarah; Dittmann, Sabine

    2008-02-01

    The dynamics and consumption of mangrove litter were investigated in two temperate Avicennia marina dominated forests in South Australia in order to compare production and fate of leaf litter with records from tropical and temperate mangroves. Litterfall was measured using traps over four months in the summer of 2004/2005. Average amount of litter was 2.1 and 3.2 g dwt m - 2 d - 1 , respectively, at the two study sites. Leaves accounted for most of the litterfall, followed by propagules and wood. Litterfall varied over time, and depending on the site and inundation time. The standing stock of leaf litter on the forest floor amounted to 15.5 g m - 2 dwt in March 2005. Decomposition determined by litter bags suggested that leaves lost ˜ 50% of their weight in the first two weeks of exposure, with little further weight loss over longer exposure times. Leaf consumption was investigated with a series of laboratory experiments, using the grapsid crab Helograpsus haswellianus, two snail species ( Salinator fragilis and Austrocochlea concamerata) and the polychaete Neanthes vaalii as potential consumers. There was no consumption of new leaves, and the only significant consumption of aged leaves was found for female H. haswellianus. H. haswellianus consumed 0.1 g dwt d - 1 of senescent leaves in the experiment, equivalent to 0.18 g m - 2 d - 1 in the field (average crab density 1.8 ind m - 2 ), or 9.4% of the average daily leaf litterfall. Experiments with propagules revealed no significant consumption by the crabs. High decomposition and low consumption rates of crabs account for the high accumulation and possible export of leaf litter from these mangroves. Leaf litter availability is not a limiting factor for invertebrate consumers in these temperate mangrove forests, and the low consumption rates imply a major difference in the fate of leaf litter between tropical and temperate mangrove systems.

  5. Detrimental Influence of Invasive Earthworms on North American Cold-Temperate Forest Soils

    Science.gov (United States)

    Enerson, Isabel

    2012-01-01

    The topic of invasive earthworms is a timely concern that goes against many preconceived notions regarding the positive benefits of all worms. In the cold-temperate forests of North America invasive worms are threatening forest ecosystems, due to the changes they create in the soil, including decreases in C:N ratios and leaf litter, disruption of…

  6. Effects of litter manipulation on litter decomposition in a successional gradients of tropical forests in southern China

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Liu, Lei

    2014-01-01

    decomposition to litter removal/addition in three successional forests in southern China, namely masson pine forest (MPF), mixed coniferous and broadleaved forest (MF) and monsoon evergreen broadleaved forest (MEBF). Results showed that litter removal decreased litter decomposition rates by 27%, 10% and 8...

  7. Fallout volume and litter type affect 137Cs concentration difference in litter between forest and stream environments.

    Science.gov (United States)

    Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N

    2016-11-01

    It is important to understand the changes in the 137 Cs concentration in litter through leaching when considering that 137 Cs is transferred from basal food resources to animals in forested streams. We found that the difference of 137 Cs activity concentration in litter between forest and stream was associated with both litter type and 137 Cs fallout volume around Fukushima, Japan. The 137 Cs activity concentrations in the litter of evergreen conifers tended to be greater than those in the litter of broad-leaved deciduous trees because of the absence of deciduous leaves during the fallout period in March 2011. Moreover, 137 Cs activity concentrations in forest litter were greater with respect to the 137 Cs fallout volume. The 137 Cs activity concentrations in stream litter were much lower than those in forest litter when those in forest litter were higher. The 137 Cs leaching patterns indicated that the differences in 137 Cs activity concentration between forest and stream litter could change with changes in both fallout volume and litter type. Because litter is an important basal food resource in the food webs of both forests and streams, the 137 Cs concentration gradient reflects to possible 137 Cs transfer from lower to higher trophic animals. Our findings will improve our understanding of the spatial heterogeneity and variability of 137 Cs concentrations in animals resident to the contaminated landscape. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Litter decomposition in southern Appalachian black locust and pine-hardwood stands: litter quality and nitrogen dynamics

    Science.gov (United States)

    David L. White; Bruce L. Haines

    1988-01-01

    The chemical quality of litter, through its interaction with macroclimate and the litter biota, largely regulates the rate of organic matter (OM) and nitrogen (N) turnover in the forest floor (Cromack 1973; Fogel and Cromack 1977; Meentemeyer 1978; Aber and Melillo 1982; Melillo et al. 1982). Litter quality is thought to be related to the N require-ment and...

  9. The fate of nitrogen mineralized from leaf litter — Initial evidence from 15N-labeled litter

    Science.gov (United States)

    Kathryn B. Piatek

    2011-01-01

    Decomposition of leaf litter includes microbial immobilization of nitrogen (N), followed by N mineralization. The fate of N mineralized from leaf litter is unknown. I hypothesized that N mineralized from leaf litter will be re-immobilized into other forms of organic matter, including downed wood. This mechanism may retain N in some forests. To test this hypothesis, oak...

  10. Checklist of Serengeti Ecosystem Grasses.

    Science.gov (United States)

    Williams, Emma Victoria; Elia Ntandu, John; Ficinski, Paweł; Vorontsova, Maria

    2016-01-01

    We present the first taxonomic checklist of the Poaceae species of the Serengeti, Tanzania. A review of the literature and herbarium specimens recorded 200 species of grasses, in line with similar studies in other parts of East Africa. The checklist is supported by a total of 939 herbarium collections. Full georeferenced collection data is made available alongside a summary checklist in pdf format. More than a quarter of the species are known from a single collection highlighting the need for further research, especially concerning the rare species and their distribution.

  11. Checklist of Serengeti Ecosystem Grasses

    Science.gov (United States)

    Ficinski, Paweł; Vorontsova, Maria

    2016-01-01

    Abstract We present the first taxonomic checklist of the Poaceae species of the Serengeti, Tanzania. A review of the literature and herbarium specimens recorded 200 species of grasses, in line with similar studies in other parts of East Africa. The checklist is supported by a total of 939 herbarium collections. Full georeferenced collection data is made available alongside a summary checklist in pdf format. More than a quarter of the species are known from a single collection highlighting the need for further research, especially concerning the rare species and their distribution. PMID:27226761

  12. The impact of alum addition on organic P transformations in poultry litter and litter-amended soil.

    Science.gov (United States)

    Warren, Jason G; Penn, Chad J; McGrath, Joshua M; Sistani, Karamat

    2008-01-01

    Poultry litter treatment with alum (Al(2)(SO(4))(3) . 18H(2)O) lowers litter phosphorus (P) solubility and therefore can lower litter P release to runoff after land application. Lower P solubility in litter is generally attributed to aluminum-phosphate complex formation. However, recent studies suggest that alum additions to poultry litter may influence organic P mineralization. Therefore, alum-treated and untreated litters were incubated for 93 d to assess organic P transformations during simulated storage. A 62-d soil incubation was also conducted to determine the fate of incorporated litter organic P, which included alum-treated litter, untreated litter, KH(2)PO(4) applied at 60 mg P kg(-1) of soil, and an unamended control. Liquid-state (31)P nuclear magnetic resonance indicated that phytic acid was the only organic P compound present, accounting for 50 and 45% of the total P in untreated and alum-treated litters, respectively, before incubation and declined to 9 and 37% after 93 d of storage-simulating incubation. Sequential fractionation of litters showed that alum addition to litter transformed 30% of the organic P from the 1.0 mol L(-1) HCl to the 0.1 mol L(-1) NaOH extractable fraction and that both organic P fractions were more persistent in alum-treated litter compared with untreated litter. The soil incubation revealed that 0.1 mol L(-1) NaOH-extractable organic P was more recalcitrant after mixing than was the 1.0 mol L(-1) HCl-extractable organic P. Thus, adding alum to litter inhibits organic P mineralization during storage and promotes the formation of alkaline extractable organic P that sustains lower P solubility in the soil environment.

  13. Subtidal littering: Indirect effects on soft substratum macrofauna?

    Directory of Open Access Journals (Sweden)

    I. AKOUMIANAKI

    2008-12-01

    Full Text Available Changes in macrofauna community structure, abundance and species richness were examined both before and one year after the deployment of plastic and glass bottles at littered (litter density: 16 items / 100 m2 and non-littered (control surfaces at three unimpacted coastal areas of the western Saronikos Gulf (Greece. In parallel, LOI% at the adjacent sediments and changes in the composition of feeding types of the megaepifauna that colonized the litter were examined across treatments. Significant changes in macrofauna community structure were demonstrated between before and after littering. At only one of the sites was there detected a significant difference in macrofauna community structure between control and littered plots after littering. This difference was linked with a significant increase in the abundance of opportunistic polychaete species and LOI% levels in the sediment surface due to the entrapment of macrophytal debris within the littered surface. The study did not show a consistent direct response of macroinfauna community to litter and the associated megafauna. Unlike the megafauna attracted by litter items, soft-substratum macrofauna is less responsive to the addition of novel hard substrates in adjacent sediments. Alternatively, it could be that the impact of littering with small items triggers a macrofauna response detectable in the long-run.

  14. Litter feedbacks, evolutionary change and exotic plant

    NARCIS (Netherlands)

    Eppinga, M.B.; Kaproth, M.A.; Collins, A.R.; Molofsky, J.

    2011-01-01

    1. Understanding the mechanisms driving exotic plant invasions is important for designing successful invader control strategies. Previous studies have highlighted different invasion mechanisms, including alteration of nutrient cycles through plant–soil feedback and evolutionary change toward more

  15. Invasive species' leaf traits and dissimilarity from natives shape their impact on nitrogen cycling: a meta-analysis.

    Science.gov (United States)

    Lee, Marissa R; Bernhardt, Emily S; van Bodegom, Peter M; Cornelissen, J Hans C; Kattge, Jens; Laughlin, Daniel C; Niinemets, Ülo; Peñuelas, Josep; Reich, Peter B; Yguel, Benjamin; Wright, Justin P

    2017-01-01

    Many exotic species have little apparent impact on ecosystem processes, whereas others have dramatic consequences for human and ecosystem health. There is growing evidence that invasions foster eutrophication. We need to identify species that are harmful and systems that are vulnerable to anticipate these consequences. Species' traits may provide the necessary insights. We conducted a global meta-analysis to determine whether plant leaf and litter functional traits, and particularly leaf and litter nitrogen (N) content and carbon: nitrogen (C : N) ratio, explain variation in invasive species' impacts on soil N cycling. Dissimilarity in leaf and litter traits among invaded and noninvaded plant communities control the magnitude and direction of invasion impacts on N cycling. Invasions that caused the greatest increases in soil inorganic N and mineralization rates had a much greater litter N content and lower litter C : N in the invaded than the reference community. Trait dissimilarities were better predictors than the trait values of invasive species alone. Quantifying baseline community tissue traits, in addition to those of the invasive species, is critical to understanding the impacts of invasion on soil N cycling. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  16. A quantitative study of seasonal foraging by the grass harvesting termite, Trinervitermes geminatus (Wasmann), (Isoptera, Nasutitermitinae) in Southern Guinea savanna, Mokwa, Nigeria.

    Science.gov (United States)

    Ohiagu, C E

    1979-01-01

    Trinervitermes geminatus (Wasmann) harvests standing grass tussocks which are cut into pieces and carried back to the nest. During this activity a certain proportion is left on the soil surface as litter whilst some is ingested. Foraging is mainly accomplished during the dry season (mid-October to the end of April) for periods of 2-4 h daily, either early in the morning, in the evening, or occasionally during both morning and evening. The duration and daily pattern of foraging is partly dependent on temperature, with a lower temperature threshold of 20° C and an upper threshold of 35° C below or above which foraging is restricted.The quantity of grass cut down and carried back to the nest by a population of 737 m -2 (3.08 g m -2 ) was estimated at 60.3 kg ha -1 a -1 with approximately 18 kg ha -1 a -1 cut and left as litter. Estimated consumption whilst foraging was approximately 20.4 kg ha -1 a -1 , giving a total consumption of about 81 kg ha -1 a -1 . Compared with a total estimated grass production of 3157 kg ha -1 a -1 and consumption by cattle of 1404 kg ha -1 a -1 , the quantity of grass removed by T. geminatus, amounting to only 3.1% of the net primary production, did not appear to be economically significant in this locality.

  17. SQ grass sublingual allergy immunotherapy tablet for disease-modifying treatment of grass pollen allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Dahl, Ronald; Roberts, Graham; de Blic, Jacques

    2016-01-01

    BACKGROUND: Allergy immunotherapy is a treatment option for allergic rhinoconjunctivitis (ARC). It is unique compared with pharmacotherapy in that it modifies the immunologic pathways that elicit an allergic response. The SQ Timothy grass sublingual immunotherapy (SLIT) tablet is approved in North...... America and throughout Europe for the treatment of adults and children (≥5 years old) with grass pollen-induced ARC. OBJECTIVE: The clinical evidence for the use of SQ grass SLIT-tablet as a disease-modifying treatment for grass pollen ARC is discussed in this review. METHODS: The review included...... the suitability of SQ grass SLIT-tablet for patients with clinically relevant symptoms to multiple Pooideae grass species, single-season efficacy, safety, adherence, coseasonal initiation, and cost-effectiveness. The data from the long-term SQ grass SLIT-tablet clinical trial that evaluated a clinical effect 2...

  18. Effect of brushwood transposition on the leaf litter arthropod fauna in a cerrado area

    Directory of Open Access Journals (Sweden)

    Paula Cristina Benetton Vergílio

    2013-10-01

    Full Text Available The results of ecological restoration techniques can be monitored through biological indicators of soil quality such as the leaf litter arthropod fauna. This study aimed to determine the immediate effect of brushwood transposition transferred from an area of native vegetation to a disturbed area, on the leaf litter arthropod fauna in a degraded cerrado area. The arthropod fauna of four areas was compared: a degraded area with signal grass, two experimental brushwood transposition areas, with and without castor oil plants, and an area of native cerrado. In total, 7,660 individuals belonging to 23 taxa were sampled. Acari and Collembola were the most abundant taxa in all studied areas, followed by Coleoptera, Diptera, Hemiptera, Hymenoptera, and Symphyla. The brushwood transposition area without castor oil plants had the lowest abundance and dominance and the highest diversity of all areas, providing evidence of changes in the soil community. Conversely, the results showed that the presence of castor oil plants hampered early succession, negatively affecting ecological restoration in this area.

  19. Marine litter in submarine canyons of the Bay of Biscay

    Science.gov (United States)

    van den Beld, Inge M. J.; Guillaumont, Brigitte; Menot, Lénaïck; Bayle, Christophe; Arnaud-Haond, Sophie; Bourillet, Jean-François

    2017-11-01

    Marine litter is a matter of increasing concern worldwide, from shallow seas to the open ocean and from beaches to the deep-seafloor. Indeed, the deep sea may be the ultimate repository of a large proportion of litter in the ocean. We used footage acquired with a Remotely Operated Vehicle (ROV) and a towed camera to investigate the distribution and composition of litter in the submarine canyons of the Bay of Biscay. This bay contains many submarine canyons housing Vulnerable Marine Ecosystems (VMEs) such as scleractinian coral habitats. VMEs are considered to be important for fish and they increase the local biodiversity. The objectives of the study were to investigate and discuss: (i) litter density, (ii) the principal sources of litter, (iii) the influence of environmental factors on the distribution of litter, and (iv) the impact of litter on benthic communities. Litter was found in all 15 canyons and at three sites on the edge of the continental shelf/canyon, in 25 of 29 dives. The Belle-île and Arcachon Canyons contained the largest amounts of litter, up to 12.6 and 9.5 items per 100 images respectively. Plastic items were the most abundant (42%), followed by fishing-related items (16%). The litter had both a maritime and a terrestrial origin. The main sources could be linked to fishing activities, major shipping lanes and river discharges. Litter appeared to accumulate at water depths of 801-1100 m and 1401-1700 m. In the deeper of these two depth ranges, litter accumulated on a geologically structured area, accounting for its high frequency at this depth. A larger number of images taken in areas of coral in the shallower of these two depth ranges may account for the high frequency of litter detection at this depth. A larger number of litter items, including plastic objects in particular, were observed on geological structures and in coral areas than on areas of bare substratum. The distribution of fishing-related items was similar for the various types of

  20. How does litter cover, litter diversity and fauna affect sediment discharge and runoff?

    Science.gov (United States)

    Goebes, Philipp; Seitz, Steffen; Kühn, Peter; Scholten, Thomas

    2013-04-01

    Litter cover plays a major role in soil erosion processes. It is known that litter cover reduces erosivity of raindrops, decreases sediment discharge and lowers runoff volume compared to bare ground. However, in the context of biodiversity, the composition of litter cover, its effect on sediment discharge and runoff volume and their influence on soil erosion have not yet been analyzed in detail. Focusing on initial soil erosion (splash), our experimental design is designated to get a better understanding of these mechanisms. The experiments were carried out within the DFG research unit "Biodiversity and Ecosystem Functioning (BEF)-China" in subtropical China. The "New Integrated Litter Experiment (NILEx)" used as platform combining different subprojects of BEF-China dealing with "decomposition and nutrient cycling", "mechanisms of soil erosion" and "functional effects of herbivores, predators and saproxylics" in one experiment. In NILEx, 96 40cm x 40cm runoff plots on two hill slopes inside a castanea molissima forest plantation have been installed and filled with seven different types of litter cover. 16 one-species plots, 24 two-species plots, 4 four-species plots and 4 bare ground plots have been set up, each replicated once. We prepared 48 Plots with traps (Renner solution) for soil macrofauna (diplopods and collembola), so half of the plots were kept free from fauna while the other half was accessible for fauna. Rainfall was generated artificially by using a rainfall simulator with a continuous and stable intensity of 60 mm/h. Our experiments included two runs of 20 minutes duration each, both conducted at two different time steps (summer 2012 and autumn 2012). Runoff volume and sediment discharge were measured every 5 minutes during one rainfall run. Litter coverage and litter mass were recorded at the beginning (summer 2012) and at the end of the experiment (autumn 2012). Our results show that sediment discharge as well as runoff volume decreases

  1. Photochemical Transformation and Bacterial Utilization of Dissolved Organic Matter and Disinfection Byproduct Precursors from Foliar Litter

    Science.gov (United States)

    Chow, A. T.; Wong, P.; O'Geen, A. T.; Dahlgren, R. A.

    2009-12-01

    Foliar litter is an important terrestrial source of dissolved organic matter (DOM) in surface water. DOM is a public health concern since it is a precursor of carcinogenic disinfection byproducts (DBPs) during drinking water treatment. Chemical characterization of in-situ water samples for their impact on water treatment may be misleading because DOM characteristics can be altered from their original composition during downstream transport to water treatment plants. In this study, we collected leachate from four fresh litters and decomposed duffs from four dominant vegetation components of California oak woodlands: blue oak (Quercus douglassi), live oak (Quercus wislizenii), foothill pine (Pinus sabiniana), and annual grasses to evaluate their DOM degradability and the reactivity of altered DOM towards DBP formation. Samples were filtered through a sterilized membrane (0.2 micron) and exposed to natural sunlight and Escherichia coli K-12 independently for 14 days. Generally speaking, leachate from decomposed duff was relatively resistant towards biodegradation compared to that from fresh litter, but the former was more susceptible to photo-transformation. Photo-bleaching caused a 30% decrease in ultra-violet absorbance at 254 nm (UVA) but no significant changes in dissolved organic carbon (DOC) concentration. This apparent loss of aromatic carbon in DOM, in terms of specific UVA, did not result in a decrease of specific trihalomethane (THM) formation potential, although aromatic carbon is considered as a major reactive site for THM formation. In addition, there were significant increases (p < 0.05) of chloral hydrate after the 14-day exposure, suggesting that the photolytic products could be a precursor of chloral hydrate. In contrast, samples inoculated with E. coli did not show a significant effect on the DOC concentration, UVA or DBP formation, although the colony counts indicated a 2-log cell growth during the 14-day incubation. Results suggest photolysis is a

  2. Litter mercury deposition in the Amazonian rainforest

    International Nuclear Information System (INIS)

    Fostier, Anne Hélène; Melendez-Perez, José Javier; Richter, Larissa

    2015-01-01

    The objective of this work was to assess the flux of atmospheric mercury transferred to the soil of the Amazonian rainforest by litterfall. Calculations were based on a large survey of published and unpublished data on litterfall and Hg concentrations in litterfall samples from the Amazonian region. Litterfall based on 65 sites located in the Amazon rainforest averaged 8.15 ± 2.25 Mg ha −1  y −1 . Average Hg concentrations were calculated from nine datasets for fresh tree leaves and ten datasets for litter, and a median concentration of 60.5 ng Hg g −1 was considered for Hg deposition in litterfall, which averaged 49 ± 14 μg m −2  yr −1 . This value was used to estimate that in the Amazonian rainforest, litterfall would be responsible for the annual removing of 268 ± 77 Mg of Hg, approximately 8% of the total atmospheric Hg deposition to land. The impact of the Amazon deforestation on the Hg biogeochemical cycle is also discussed. - Highlights: • Based on published data we estimated the litterfall in the Amazonian rainforest. • All the published data on Hg concentration in leaves and litter from the region and some unpublished data are presented. • We calculated the litter mercury deposition. • We estimated the contribution of dry, wet and litter Hg deposition in the Amazonian rainforest. • We also discussed the impact of Amazon deforestation on the Hg biogeochemical cycle. - The Amazonian rainforest is responsible for removing at least 268 Mg Hg y −1 , 8% of the total atmospheric mercury deposition to land.

  3. Laboratory and field evaluation of broiler litter nitrogen mineralization.

    Science.gov (United States)

    Sistani, K R; Adeli, A; McGowen, S L; Tewolde, H; Brink, G E

    2008-05-01

    Two studies were conducted for this research. First, a laboratory incubation to quantify broiler litter N mineralization with the following treatments: two soil moisture regimes, constant at 60% water fill pore space (WFPS) and fluctuating (60-30% WFPS), three soil types, Brooksville silty clay loam, Ruston sandy loam from Mississippi, and Catlin silt loam from Illinois. Second, a field incubation study to quantify broiler litter N mineralization using similar soils and litter application rates as the laboratory incubation. Broiler litter was applied at an equivalent rate of 350 kg total N ha(-1) for both studies except for control treatments. Subsamples were taken at different timing for both experiments for NO3-N and NH4-N determinations. In the laboratory experiment, soil moisture regimes had no significant impact on litter-derived inorganic N. Total litter-derived inorganic N across all treatments increased from 23 mg kg(-1) at time 0, to 159 mg kg(-1) at 93 d after litter application. Significant differences were observed among the soil types. Net litter-derived inorganic N was greater for Brooksville followed by Ruston and Catlin soils. For both studies and all soils, NH4-N content decreased while NO3-N content increased indicating a rapid nitrification of the mineralized litter N. Litter mineralization in the field study followed the same trend as the laboratory study but resulted in much lower net inorganic N, presumably due to environmental conditions such as precipitation and temperature, which may have resulted in more denitrification and immobilization of mineralized litter N. Litter-derived inorganic N from the field study was greater for Ruston than Brooksville. Due to no impact by soil moisture regimes, additional studies are warranted in order to develop predictive relationships to quantify broiler litter N availability.

  4. Large-scale downy brome treatments alter plant-soil relationships and promote perennial grasses in salt desert shrublands

    Science.gov (United States)

    The interrelationship between invasive annual grass abundance and soil resource availability varies spatially and temporally within ecosystems and may be altered by land treatments. We evaluated these relationships in two salt desert landscapes where the local abundance of Bromus tectorum L. (downy...

  5. Can native annual forbs reduce Bromus tectorum biomass and indirectly facilitate establishment of a native perennial grass?

    Science.gov (United States)

    Elizabeth A. Leger; Erin M. Goergen; Tara Forbis de Queiroz

    2014-01-01

    Restoration is challenging in systems invaded by competitive, disturbance oriented plants, but greater success may be achieved by mimicking natural successional processes and including disturbanceoriented natives in a seed mix. We asked whether seven native annual forbs from the Great Basin Desert, USA, were capable of reducing biomass of the invasive annual grass...

  6. Introducing litter quality to the ecosystem model LPJ-GUESS: Effects on short- and long-term soil carbon dynamics

    Science.gov (United States)

    Portner, Hanspeter; Wolf, Annett; Rühr, Nadine; Bugmann, Harald

    2010-05-01

    Many biogeochemical models have been applied to study the response of the carbon cycle to changes in climate, whereby the process of carbon uptake (photosynthesis) has usually gained more attention than the equally important process of carbon release by respiration. The decomposition of soil organic matter is driven by a combination of factors like soil temperature, soil moisture and litter quality. We have introduced dependence on litter substrate quality to heterotrophic soil respiration in the ecosystem model LPJ-GUESS [Smith et al.(2001)]. We were interested in differences in model projections before and after the inclusion of the dependency both in respect to short- and long-term soil carbon dynamics. The standard implementation of heterotrophic soil respiration in LPJ-GUESS is a simple carbon three-pool model whose decay rates are dependent on soil temperature and soil moisture. We have added dependence on litter quality by coupling LPJ-GUESS to the soil carbon model Yasso07 [Tuomi et al.(2008)]. The Yasso07 model is based on an extensive number of measurements of litter decomposition of forest soils. Apart from the dependence on soil temperature and soil moisture, the Yasso07 model uses carbon soil pools representing different substrate qualities: acid hydrolyzable, water soluble, ethanol soluble, lignin compounds and humus. Additionally Yasso07 differentiates between woody and non-woody litter. In contrary to the reference implementation of LPJ-GUESS, in the new model implementation, the litter now is divided according to its specific quality and added to the corresponding soil carbon pool. The litter quality thereby differs between litter source (leaves, roots, stems) and plant functional type (broadleaved, needleleaved, grass). The two contrasting model implementations were compared and validated at one specific CarboEuropeIP site (Lägern, Switzerland) and on a broader scale all over Switzerland. Our focus lay on the soil respiration for the years 2006

  7. Bioenergy production from roadside grass

    DEFF Research Database (Denmark)

    Meyer, Ane Katharina Paarup; Ehimen, Ehiazesebhor Augustine; Holm-Nielsen, Jens Bo

    2014-01-01

    .5–3.0% of the present national energy production based on biogas. The estimated values for the energy return on invested energy (EROEI) was found to range from 2.17 to 2.88. The measured contents of heavy metals in the roadside vegetation was seen not to exceed the legislative levels for what can be applied......This paper presents a study of the feasibility of utilising roadside vegetation for biogas production in Denmark. The potential biomass yield, methane yields, and the energy balances of using roadside grass for biogas production was investigated based on spatial analysis. The results show...... that the potential annual yield of biomass obtainable from roadside verges varies widely depending on the local conditions. The net energy gain (NEG) from harvest, collection, transport, storage and digestion of roadside vegetation was estimated to range from 60,126–121,476 GJ, corresponding to 1...

  8. The effects of UV radiation, litter chemistry, and drought on desert litter decomposition

    Science.gov (United States)

    Lee, H.; Nieto, B.; Hewins, D. B.; Barnes, P. W.; McDowell, N. G.; Pockman, W.; Rahn, T.; Throop, H. L.

    2011-12-01

    Recent studies suggest that photodegradation by solar UV radiation can be a major driver of litter decomposition in dryland ecosystems. The importance of photodegradation in litter decomposition appears to decline with precipitation, suggesting that the relative importance of photodegradation may increase given current projections of future increases in drought severity in the southwestern USA. Several previous studies indicate that UV-B radiation (280-320 nm) is the most effective waveband in breaking chemical bonds forming organic material, but whether UV-B exposure may facilitate subsequent decomposition by microbes (i.e., photo-priming) has received little attention. In this study, we tested the effects of pre-exposure UV radiation (photo-priming), litter chemistry (lignin and cellulose content and nitrogen content), and drought on the rate of litter decomposition in a semi-arid ecosystem. To understand the effects of UV radiation on litter decomposition, we pre-exposed litter to three radiation treatments: control (no radiation), UV-A+visible, UV-A+UV-B+visible. Litter was exposed to the equivalent of three months' solar radiation of southern New Mexico prior to microbial decomposition. There were three litter types: basswood sheets (high lignin content), pure cellulose filter paper, and mesquite (Prosopis glandulosa) leaflets. Following radiation treatment, litter was placed in mesh litterbags that were buried within a large-scale precipitation manipulation experiment at the Sevilleta Long-Term Ecological Research site: control (ambient precipitation), elevated precipitation (x2 ambient precipitation), and drought (x0.5 ambient precipitation). We collected a subset of bags at 0, 1, 3, and 6 months and measured mass remaining and carbon (C) and nitrogen (N) content. After 6 months, mass remaining of filter paper and basswood sheets did not differ from the initial mass, but mesquite mass remaining declined over 30%. The pre-exposure UV effects had minimal

  9. Debris is not a cheese: litter in coastal Louisiana

    Science.gov (United States)

    Lindstedt, Dianne M.; Holmes, Joseph C.

    1989-01-01

    An 18-month study of six Louisiana beaches determined the extent, composition, and possible sources of beach litter. Data showed that from 2590 to 23,154 items may be encountered along any one-mile stretch of Louisiana beach, depending upon location and season, and that densities of litter ranged from 5 to 28 items per 100 m2. Plastics constituted 47% of the total, followed by polystyrene at 16% and glass at 10%. Drink-related items accounted for 40% of the identifiable material; operational wastes, 21%; galley wastes, 15%; personal items, 11%; and fishing items, 6%. Litter laws already exist at state and federal levels. Strict enforcement of Annex V of MARPOL should significantly reduce plastic beach litter. Solutions to beach litter will come from public participation in adopt-a-beach programs and statewide clean-ups and from educational programs focusing on existing laws, proper disposal methods, recycling, and the threat litter poses to wildlife and public health.

  10. Grass leaves as potential hominin dietary resources.

    Science.gov (United States)

    Paine, Oliver C C; Koppa, Abigale; Henry, Amanda G; Leichliter, Jennifer N; Codron, Daryl; Codron, Jacqueline; Lambert, Joanna E; Sponheimer, Matt

    2018-04-01

    Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C 4 component in the diets of most taxa, and grass leaves are the single most abundant C 4 resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of grass leaves with the plants growing alongside them in African savanna habitats. We also compare grass leaves to the leaves consumed by other hominoids and demonstrate that many, though by no means all, compare favorably with the nutritional and mechanical properties of known primate foods. Our data reveal that grass leaves exhibit tremendous variation and suggest that future reconstructions of hominin dietary ecology take a more nuanced approach when considering grass leaves as a potential hominin dietary resource. Copyright © 2017. Published by Elsevier Ltd.

  11. Investigating Prosocial Behavior: A Case Study of Littering in Laos

    OpenAIRE

    Norrgren, Lisa; Swahnberg, Hanna

    2016-01-01

    Using vignette experiments, this thesis examines individuals’ decision-making in various social dilemmas. A case study of littering behavior amongst university students in Lao People's Democratic Republic is used to investigate whether individual preferences are stable across littering dilemmas and other social dilemmas. This study further investigates if a visual prompt can encourage prosocial behavior in littering situations. The results show that behavior in social dilemmas is dependent on...

  12. Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter.

    Directory of Open Access Journals (Sweden)

    Cassandra D Smith

    Full Text Available Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ' was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1. Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., < 1.0, at the highest interspecific densities in the dry treatment. Dry treatment litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition

  13. X meeting utenti GRASS e GFOSS

    Directory of Open Access Journals (Sweden)

    Francesco Marucci

    2009-03-01

    Full Text Available 10th meeting of GRASS & GFOSS users The 10th Italian Congress of GRASS GIS and Geospatial Free and Open Source Software (GFOSS was held on the26 and 27 Feb in Cagliari. Highlights included updates on major GFOSS projects (GRASS, QGIS, the presentation of new projects (SpatiaLite and the public release of a free 3D visualization application suitable for distribution over the internet (RATMAN. Many users and developers connected to forge new business relationships and share new ideas.

  14. X meeting utenti GRASS e GFOSS

    Directory of Open Access Journals (Sweden)

    Francesco Marucci

    2009-03-01

    Full Text Available 10th meeting of GRASS & GFOSS usersThe 10th Italian Congress of GRASS GIS and Geospatial Free and Open Source Software (GFOSS was held on the26 and 27 Feb in Cagliari. Highlights included updates on major GFOSS projects (GRASS, QGIS, the presentation of new projects (SpatiaLite and the public release of a free 3D visualization application suitable for distribution over the internet (RATMAN. Many users and developers connected to forge new business relationships and share new ideas.

  15. Perrenial Grasses for Sustainable European Protein Production

    DEFF Research Database (Denmark)

    Jørgensen, Uffe; Lærke, Poul Erik

    2016-01-01

    benefits, a reduction of nitrate leaching equivalent to 23,000 tonnes N annually was estimated. This is approximately the reduction required by the WFD for Denmark. Even though much more organic matter will be mobilized for biorefining, soil carbon levels are estimated to be largely unchanged...... production into grass production. Grasses and legumes have higher contents of protein with better quality (high lysine and methionine contents) than grain and seed crops. Thus, substituting imported soya bean protein with protein extracted from perennial grasses is an interesting option....

  16. Does plant uptake or low soil mineral-N production limit mineral-N losses to surface waters and groundwater from soils under grass in summer?

    International Nuclear Information System (INIS)

    Bhatti, Ambreen; McClean, Colin J.; Cresser, Malcolm S.

    2013-01-01

    Summer minima and autumn/winter maxima in nitrate concentrations in rivers are reputedly due to high plant uptake of nitrate from soils in summer. A novel alternative hypothesis is tested here for soils under grass. By summer, residual readily mineralizable plant litter from the previous autumn/winter is negligible and fresh litter input low. Consequently little mineral-N is produced in the soil. Water-soluble and KCl-extractable mineral N in fresh soils and soils incubated outdoors for 7 days have been monitored over 12 months for soil transects at two permanent grassland sites near York, UK, using 6 replicates throughout. Vegetation-free soil is shown to produce very limited mineral-N in summer, despite the warm, moist conditions. Litter accumulates in autumn/winter and initially its high C:N ratio favours N accumulation in the soil. It is also shown that mineral-N generated monthly in situ in soil substantially exceeds the monthly mineral-N inputs via wet deposition at the sites. -- Highlights: •Soil mineral-N has been measured over a year at two grassland sites in the UK. •Rates of mineral-N production have also been measured in vegetation-free soils. •In summer, though soils were warm and moist, rate of mineral-N production was low. •The effect is attributed to low litter inputs in summer when grass is growing well. •Low mineral-N production in summer must be limiting N losses to fresh waters. -- Low mineral-N production in soils under grass limits summer N losses to surface- and ground-waters

  17. Changes in plant functional groups, litter quality, and soil carbon and nitrogen mineralization with sheep grazing in an Inner Mongolian Grassland

    Science.gov (United States)

    Barger, N.N.; Ojima, D.S.; Belnap, J.; Shiping, W.; Yanfen, W.; Chen, Z.

    2004-01-01

    This study reports on changes in plant functional group composition, litter quality, and soil C and N mineralization dynamics from a 9-year sheep grazing study in Inner Mongolia. Addressed are these questions: 1) How does increasing grazing intensity affect plant community composition? 2) How does increasing grazing intensity alter soil C and N mineralization dynamics? 3) Do changes in soil C and N mineralization dynamics relate to changes in plant community composition via inputs of the quality or quantity of litter? Grazing plots were set up near the Inner Mongolia Grassland Ecosystem Research Station (IMGERS) with 5 grazing intensities: 1.3, 2.7, 4.0, 5.3, and 6.7 sheep ha -1??yr-1. Plant cover was lower with increasing grazing intensity, which was primarily due to a dramatic decline in grasses, Carex duriuscula, and Artemisia frigida. Changes in litter mass and percentage organic C resulted in lower total C in the litter layer at 4.0 and 5.3 sheep ha-1??yr-1 compared with 2.7 sheep ha -1??yr-1. Total litter N was lower at 5.3 sheep ha-1??yr-1 compared with 2.7 sheep ha -1??yr-1. Litter C:N ratios, an index of litter quality, were significantly lower at 4.0 sheep ha-1??yr -1 relative to 1.3 and 5.3 sheep ha-1??yr -1. Cumulative C mineralized after 16 days decreased with increasing grazing intensity. In contrast, net N mineralization (NH4+ + NO3-) after a 12-day incubation increased with increasing grazing intensity. Changes in C and N mineralization resulted in a narrowing of CO2-C:net Nminratios with increasing grazing intensity. Grazing explained 31% of the variability in the ratio of CO 2-C:net Nmin. The ratio of CO2-C:net N min was positively correlated with litter mass. Furthermore, there was a positive correlation between litter mass and A. frigida cover. Results suggest that as grazing intensity increases, microbes become more C limited resulting in decreased microbial growth and demand for N.

  18. Competence of Litter Ants for Rapid Biodiversity Assessments

    Directory of Open Access Journals (Sweden)

    T. H. Saumya E. Silva

    2017-01-01

    Full Text Available Rapid Biodiversity Assessment approaches associated with focusing taxa have overcome many of the problems related to large scale surveys. This study examined the suitability of litter ants as a focusing taxon by checking whether diversity and species assemblages of litter ants reflect the overall picture of arthropod diversity and assemblages in leaf litter in two vegetation types: secondary forest and pine plantation in Upper Hanthana forest reserve, Sri Lanka. In each vegetation type, arthropods were sampled using three sampling methods (Winkler extraction, hand collection, and pitfall traps along three 100 m line transects. From the two sites, 1887 litter ants (34 species and 3488 litter arthropods (52 species were collected. Species assemblages composition of both ants and other arthropods differed significantly between the two sites (ANOSIM, p=0.001 with both groups generating distinct clusters for the two sites (SIMPROF, p=0.001. But there was no significant correlation (p>0.05 between abundance and richness of litter ants and those of other arthropods in both vegetation types. The overall finding suggests that the litter ants do not reflect the holistic picture of arthropod diversity and assemblages in leaf litter, but the quality of the habitat for the survival of all litter arthropods.

  19. Controls over leaf litter decomposition in wet tropical forests.

    Science.gov (United States)

    Wieder, William R; Cleveland, Cory C; Townsend, Alan R

    2009-12-01

    Tropical forests play a substantial role in the global carbon (C) cycle and are projected to experience significant changes in climate, highlighting the importance of understanding the factors that control organic matter decomposition in this biome. In the tropics, high temperature and rainfall lead to some of the highest rates of litter decomposition on earth, and given the near-optimal abiotic conditions, litter quality likely exerts disproportionate control over litter decomposition. Yet interactions between litter quality and abiotic variables, most notably precipitation, remain poorly resolved, especially for the wetter end of the tropical forest biome. We assessed the importance of variation in litter chemistry and precipitation in a lowland tropical rain forest in southwest Costa Rica that receives >5000 mm of precipitation per year, using litter from 11 different canopy tree species in conjunction with a throughfall manipulation experiment. In general, despite the exceptionally high rainfall in this forest, simulated throughfall reductions consistently suppressed rates of litter decomposition. Overall, variation between species was greater than that induced by manipulating throughfall and was best explained by initial litter solubility and lignin:P ratios. Collectively, these results support a model of litter decomposition in which mass loss rates are positively correlated with rainfall up to very high rates of mean annual precipitation and highlight the importance of phosphorus availability in controlling microbial processes in many lowland tropical forests.

  20. Marine litter in the Nordic Seas: Distribution composition and abundance.

    Science.gov (United States)

    Buhl-Mortensen, Lene; Buhl-Mortensen, Pål

    2017-12-15

    Litter has been found in all marine environments and is accumulating in seabirds and mammals in the Nordic Seas. These ecosystems are under pressure from climatic change and fisheries while the human population is small. The marine landscapes in the area range from shallow fishing banks to deep-sea canyons. We present density, distribution and composition of litter from the first large-scale mapping of sea bed litter in arctic and subarctic waters. Litter was registered from 1778 video transects, of which 27% contained litter. The background density of litter in the Barents Sea and Norwegian Sea is 202 and 279 items/km 2 respectively, and highest densities were found close to coast and in canyons. Most of the litter originated from the fishing industry and plastic was the second most common litter. Background levels were comparable to European records and areas with most littering had higher densities than in Europe. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Genome sequence analysis of the model grass Brachypodium distachyon: insights into grass genome evolution

    Energy Technology Data Exchange (ETDEWEB)

    Schulman, Al

    2009-08-09

    Three subfamilies of grasses, the Erhardtoideae (rice), the Panicoideae (maize, sorghum, sugar cane and millet), and the Pooideae (wheat, barley and cool season forage grasses) provide the basis of human nutrition and are poised to become major sources of renewable energy. Here we describe the complete genome sequence of the wild grass Brachypodium distachyon (Brachypodium), the first member of the Pooideae subfamily to be completely sequenced. Comparison of the Brachypodium, rice and sorghum genomes reveals a precise sequence- based history of genome evolution across a broad diversity of the grass family and identifies nested insertions of whole chromosomes into centromeric regions as a predominant mechanism driving chromosome evolution in the grasses. The relatively compact genome of Brachypodium is maintained by a balance of retroelement replication and loss. The complete genome sequence of Brachypodium, coupled to its exceptional promise as a model system for grass research, will support the development of new energy and food crops

  2. Grass survey of the Itremo Massif records endemic central highland ...

    African Journals Online (AJOL)

    Twenty species are endemic to the central highlands, and a further 1 4 species are restricted to Madagascar. Five ecological groups of grasses were identified in the Itremo Massif: shade species in gallery forests, open wet area species, fire grasses, anthropogenic disturbance associated grasses and rock-dwelling grasses.

  3. Invasion resistance and persistence: established plants win, even with disturbance and high propagule pressure

    Science.gov (United States)

    Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb

    2011-01-01

    Disturbances and propagule pressure are key mechanisms in plant community resistance to invasion, as well as persistence of invasions. Few studies, however, have experimentally tested the interaction of these two mechanisms. We initiated a study in a southwestern ponderosa pine (Pinus ponderosa Laws.)/bunch grass system to determine the susceptibility of remnant native...

  4. Evaluating hybridization as a potential facilitator of successful cogongrass (Imperata cylindrica) invasion in Florida, USA

    Science.gov (United States)

    Rima Lucardi; L.E. Wallace; G.N. Ervin

    2014-01-01

    Interspecific hybridization is cited as one potential mechanism for increased invasiveness, particularly among some grass species. In the southeastern United States, the successful invasion of cogongrass (Imperata cylindrica) has sometimes been attributed to hybridization with the previously naturalized Imperata brasiliensis. This...

  5. Post-fire Downy Brome (Bromus tectorum) invasion at high elevation in Wyoming

    Science.gov (United States)

    The invasive annual grass downy brome is the most ubiquitous weed in sagebrush systems of western North America. The center of invasion has largely been the Great Basin region, but there is an increasing abundance and distribution in the Rocky Mountain States. We evaluated post-fire vegetation chang...

  6. Expansion of invasive species on ombrotrophic bogs: desiccation or high N deposition?

    NARCIS (Netherlands)

    Tomassen, H.B.M.; Smolders, A.J.P.; Limpens, J.; Lamers, L.P.M.; Roelofs, J.G.M.

    2004-01-01

    1. In many ombrotrophic bog areas the invasion of grass (e.g. Molinia caerulea) and tree (e.g. Betula pubescens) species has become a major problem. We investigated whether the invasion of such species is due to high atmospheric nitrogen (N) deposition by conducting a fertilization experiment. 2.

  7. Resistance to invasion and resilience to fire in desert shrublands of North America

    Science.gov (United States)

    Matthew L. Brooks; Jeanne C. Chambers

    2011-01-01

    Settlement by Anglo-Americans in the desert shrublands of North America resulted in the introduction and subsequent invasion of multiple nonnative grass species. These invasions have altered presettlement fire regimes, resulted in conversion of native perennial shrublands to nonnative annual grasslands, and placed many native desert species at risk. Effective...

  8. Tropical herbivorous phasmids, but not litter snails, alter decomposition rates by modifying litter bacteria

    Science.gov (United States)

    Chelse M. Prather; Gary E. Belovsky; Sharon A. Cantrell; Grizelle González

    2018-01-01

    Consumers can alter decomposition rates through both feces and selective feeding in many ecosystems, but these combined effects have seldom been examined in tropical ecosystems. Members of the detrital food web (litter-feeders or microbivores) should presumably have greater effects on decomposition than herbivores, members of the green food web. Using litterbag...

  9. Life in leaf litter: novel insights into community dynamics of bacteria and fungi during litter decomposition.

    Science.gov (United States)

    Purahong, Witoon; Wubet, Tesfaye; Lentendu, Guillaume; Schloter, Michael; Pecyna, Marek J; Kapturska, Danuta; Hofrichter, Martin; Krüger, Dirk; Buscot, François

    2016-08-01

    Microorganisms play a crucial role in the biological decomposition of plant litter in terrestrial ecosystems. Due to the permanently changing litter quality during decomposition, studies of both fungi and bacteria at a fine taxonomic resolution are required during the whole process. Here we investigated microbial community succession in decomposing leaf litter of temperate beech forest using pyrotag sequencing of the bacterial 16S and the fungal internal transcribed spacer (ITS) rRNA genes. Our results reveal that both communities underwent rapid changes. Proteobacteria, Actinobacteria and Bacteroidetes dominated over the entire study period, but their taxonomic composition and abundances changed markedly among sampling dates. The fungal community also changed dynamically as decomposition progressed, with ascomycete fungi being increasingly replaced by basidiomycetes. We found a consistent and highly significant correlation between bacterial richness and fungal richness (R = 0.76, P kingdom co-occurrence pattern of their communities from the early to the later stages of decomposition. During this process, macronutrients, micronutrients, C:N ratio and pH were significantly correlated with the fungal and bacterial communities, while bacterial richness positively correlated with three hydrolytic enzymes important for C, N and P acquisition. Overall, we provide evidence that the complex litter decay is the result of a dynamic cross-kingdom functional succession. © 2016 John Wiley & Sons Ltd.

  10. Underwater Grass Comeback Helps Chesapeake Bay

    Science.gov (United States)

    The fortified Susquehanna Flats, the largest bed of underwater grasses in the Chesapeake Bay, seems able to withstand a major weather punch. Its resilience is contributing to an overall increase in the Bay’s submerged aquatic vegetation.

  11. Karl Konrad Grass jumalainimeste uurijana / Alar Laats

    Index Scriptorium Estoniae

    Laats, Alar

    2006-01-01

    Karl Konrad Grass oli 19. sajandil Dorpati keiserliku ülikooli usuteaduskonna Uue Testamendi õppejõud, kes tegeles hobi korras idakristluse (vene sektid) uurimisega. Tema peateoseks on uurimus "Die russischen Sekten". Ettekanne konverentsil 15.-16. aprill 2005. a.

  12. Tree-grass interactions in savannas

    CSIR Research Space (South Africa)

    Scholes, RJ

    1997-01-01

    Full Text Available Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign...

  13. Pampas Grass - Orange Co. [ds351

    Data.gov (United States)

    California Department of Resources — This dataset provides the known distribution of pampas grass (Cortaderia selloana) in southern Orange County. The surveys were conducted from May to June, 2007 and...

  14. The role of reproduction in Glyceria maxima invasion | Mugwedi ...

    African Journals Online (AJOL)

    Glyceria maxima (Poaceae) is regarded as one of the most invasive grasses worldwide, but has only recently become naturalised in South Africa after its intentional introduction as a fodder crop in the 1940s. It invades seasonally inundated habitats. The primary reproduction mode of G. maxima within established ...

  15. Phenology of exotic invasive weeds associated with downy brome

    Science.gov (United States)

    The exotic and highly invasive annual grass downy brome (Bromus tectorum) has invaded millions of hectares of rangelands throughout the Intermountain West. Downy brome increases the chance, rate, season and spread of wildfires, resulting in the destruction of native plant communities and the wildli...

  16. Exploring the invasion of rangelands by Acacia mearnsii (black ...

    African Journals Online (AJOL)

    Reducing A. mearnsii canopy could promote grass production while encouraging carbon sequestration. Given the high AGB and clearing costs, it may be prudent to adopt the 'novel ecosystems' approach in managing infested landscapes. Keywords: grassland, invasive plants, landscape ecology, rangeland condition ...

  17. Radiocesium leaching from contaminated litter in forest streams

    International Nuclear Information System (INIS)

    Sakai, Masaru; Gomi, Takashi; Naito, Risa S.; Negishi, Junjiro N.; Sasaki, Michiko; Toda, Hiroto; Nunokawa, Masanori; Murase, Kaori

    2015-01-01

    In Japanese forests suffering from the Fukushima Daiichi Nuclear Power Plant accident, litter fall provides a large amount of radiocesium from forests to streams. Submerged litter is processed to become a vital food resource for various stream organisms through initial leaching and subsequent decomposition. Although leaching from litter can detach radiocesium similarly to potassium, radiocesium leaching and its migration are poorly understood. We examined both radiocesium and potassium leaching to the water column and radiocesium allocation to minerals (glass beads, silica sand, and vermiculite) in the laboratory using soaked litter with and without minerals on a water column. The mineral types did not affect radiocesium leaching from litter, but soaking in water for 1, 7, and 30 days decreased the radiocesium concentration in litter by ×0.71, ×0.66, and ×0.56, respectively. Meanwhile, the 1-, 7-, and 30-day experiments decreased potassium concentration in litter by ×0.17, ×0.11, and ×0.09, respectively. Leached radiocesium remained in a dissolved form when there was no mineral phases present in the water, whereas there was sorption onto the minerals when they were present. In particular, vermiculite adsorbed radiocesium by two to three orders of magnitude more effectively than the other minerals. Because radiocesium forms (such as that dissolved or adsorbed to organic matter or minerals) can further mobilize to ecosystems, our findings will increase our understanding regarding the dynamics of radiocesium in stream ecosystems. - Highlights: • Radiocesium in contaminated litter was leached when soaked in water. • Radiocesium in litter leached slowly compared to potassium. • Minerals adsorbed dissolved radiocesium that was leached from litter. • Vermiculite effectively adsorbed radiocesium leached from litter

  18. Elephant grass as forage for ruminant animals

    OpenAIRE

    Rusdy, Muhammad

    2016-01-01

    The shortage of feed, particularly during the dry season is one of the major factor limiting productivity of livestock in the tropics. Napier or elephant grass (Pennisetum purpureum Schum.) shows a great potential to alleviate the problem because it is drought resistant and has high dry matter yield potential. As an attempt to generate information useful for improving the utilization of the grass, its potential and limitation are described. Its chemical composition and nutritive value as rela...

  19. Interacting microbe and litter quality controls on litter decomposition: a modeling analysis.

    Directory of Open Access Journals (Sweden)

    Daryl Moorhead

    Full Text Available The decomposition of plant litter in soil is a dynamic process during which substrate chemistry and microbial controls interact. We more clearly quantify these controls with a revised version of the Guild-based Decomposition Model (GDM in which we used a reverse Michaelis-Menten approach to simulate short-term (112 days decomposition of roots from four genotypes of Zea mays that differed primarily in lignin chemistry. A co-metabolic relationship between the degradation of lignin and holocellulose (cellulose+hemicellulose fractions of litter showed that the reduction in decay rate with increasing lignin concentration (LCI was related to the level of arabinan substitutions in arabinoxylan chains (i.e., arabinan to xylan or A∶X ratio and the extent to which hemicellulose chains are cross-linked with lignin in plant cell walls. This pattern was consistent between genotypes and during progressive decomposition within each genotype. Moreover, decay rates were controlled by these cross-linkages from the start of decomposition. We also discovered it necessary to divide the Van Soest soluble (labile fraction of litter C into two pools: one that rapidly decomposed and a second that was more persistent. Simulated microbial production was consistent with recent studies suggesting that more rapidly decomposing materials can generate greater amounts of potentially recalcitrant microbial products despite the rapid loss of litter mass. Sensitivity analyses failed to identify any model parameter that consistently explained a large proportion of model variation, suggesting that feedback controls between litter quality and microbial activity in the reverse Michaelis-Menten approach resulted in stable model behavior. Model extrapolations to an independent set of data, derived from the decomposition of 12 different genotypes of maize roots, averaged within <3% of observed respiration rates and total CO2 efflux over 112 days.

  20. Genetic compatibility determines endophyte-grass combinations.

    Directory of Open Access Journals (Sweden)

    Kari Saikkonen

    Full Text Available Even highly mutually beneficial microbial-plant interactions, such as mycorrhizal- and rhizobial-plant exchanges, involve selfishness, cheating and power-struggles between the partners, which depending on prevailing selective pressures, lead to a continuum of interactions from antagonistic to mutualistic. Using manipulated grass-endophyte combinations in a five year common garden experiment, we show that grass genotypes and genetic mismatches constrain genetic combinations between the vertically (via host seeds transmitted endophytes and the out-crossing host, thereby reducing infections in established grass populations. Infections were lost in both grass tillers and seedlings in F(1 and F(2 generations, respectively. Experimental plants were collected as seeds from two different environments, i.e., meadows and nearby riverbanks. Endophyte-related benefits to the host included an increased number of inflorescences, but only in meadow plants and not until the last growing season of the experiment. Our results illustrate the importance of genetic host specificity and trans-generational maternal effects on the genetic structure of a host population, which act as destabilizing forces in endophyte-grass symbioses. We propose that (1 genetic mismatches may act as a buffering mechanism against highly competitive endophyte-grass genotype combinations threatening the biodiversity of grassland communities and (2 these mismatches should be acknowledged, particularly in breeding programmes aimed at harnessing systemic and heritable endophytes to improve the agriculturally valuable characteristics of cultivars.

  1. Madagascar's grasses and grasslands: anthropogenic or natural?

    Science.gov (United States)

    Besnard, Guillaume; Forest, Félix; Malakasi, Panagiota; Moat, Justin; Clayton, W. Derek; Ficinski, Paweł; Savva, George M.; Nanjarisoa, Olinirina P.; Razanatsoa, Jacqueline; Randriatsara, Fetra O.; Kimeu, John M.; Luke, W. R. Quentin; Kayombo, Canisius; Linder, H. Peter

    2016-01-01

    Grasses, by their high productivity even under very low pCO2, their ability to survive repeated burning and to tolerate long dry seasons, have transformed the terrestrial biomes in the Neogene and Quaternary. The expansion of grasslands at the cost of biodiverse forest biomes in Madagascar is often postulated as a consequence of the Holocene settlement of the island by humans. However, we show that the Malagasy grass flora has many indications of being ancient with a long local evolutionary history, much predating the Holocene arrival of humans. First, the level of endemism in the Madagascar grass flora is well above the global average for large islands. Second, a survey of many of the more diverse areas indicates that there is a very high spatial and ecological turnover in the grass flora, indicating a high degree of niche specialization. We also find some evidence that there are both recently disturbed and natural stable grasslands: phylogenetic community assembly indicates that recently severely disturbed grasslands are phylogenetically clustered, whereas more undisturbed grasslands tend to be phylogenetically more evenly distributed. From this evidence, it is likely that grass communities existed in Madagascar long before human arrival and so were determined by climate, natural grazing and other natural factors. Humans introduced zebu cattle farming and increased fire frequency, and may have triggered an expansion of the grasslands. Grasses probably played the same role in the modification of the Malagasy environments as elsewhere in the tropics. PMID:26791612

  2. Dietary flexibility aids Asian earthworm invasion in North American forests.

    Science.gov (United States)

    Zhang, Weixin; Hendrix, Paul F; Snyder, Bruce A; Molina, Marirosa; Li, Jianxiong; Rao, Xingquan; Siemann, Evan; Fu, Shenglei

    2010-07-01

    On a local scale, invasiveness of introduced species and invasibility of habitats together determine invasion success. A key issue in invasion ecology has been how to quantify the contribution of species invasiveness and habitat invasibility separately. Conventional approaches, such as comparing the differences in traits and/or impacts of species between native and/or invaded ranges, do not determine the extent to which the performance of invaders is due to either the effects of species traits or habitat characteristics. Here we explore the interaction between two of the most widespread earthworm invaders in the world (Asian Amynthas agrestis and European Lumbricus rubellus) and study the effects of species invasiveness and habitat invasibility separately through an alternative approach of "third habitat" in Tennessee, USA. We propose that feeding behaviors of earthworms will be critical to invasion success because trophic ecology of invasive animals plays a key role in the invasion process. We found that (1) the biomass and isotopic abundances (delta13C and delta15N) of A. agrestis were not impacted by either direct effects of L. rubellus competition or indirect effects of L. rubellus-preconditioned habitat; (2) A. agrestis disrupted the relationship between L. rubellus and soil microorganisms and consequently hindered litter consumption by L. rubellus; and (3) compared to L. rubellus, A. agrestis shifted its diet more readily to consume more litter, more soil gram-positive (G+) bacteria (which may be important for litter digestion), and more non-microbial soil fauna when soil microorganisms were depleted. In conclusion, A. agrestis showed strong invasiveness through its dietary flexibility through diet shifting and superior feeding behavior and its indirectly negative effect of habitat invasibility on L. rubellus via changes in the soil microorganism community. In such context, our results expand on the resource fluctuation hypothesis and support the superior

  3. Treatment with grass allergen peptides improves symptoms of grass pollen-induced allergic rhinoconjunctivitis.

    Science.gov (United States)

    Ellis, Anne K; Frankish, Charles W; O'Hehir, Robyn E; Armstrong, Kristen; Steacy, Lisa; Larché, Mark; Hafner, Roderick P

    2017-08-01

    Synthetic peptide immunoregulatory epitopes are a new class of immunotherapy to treat allergic rhinoconjunctivitis (ARC). Grass allergen peptides, comprising 7 synthetic T-cell epitopes derived from Cyn d 1, Lol p 5, Dac g 5, Hol l 5, and Phl p 5, is investigated for treatment of grass pollen-induced ARC. We sought to evaluate the efficacy, safety, and tolerability of intradermally administered grass allergen peptides. A multicenter, randomized, double-blind, placebo-controlled study evaluated 3 regimens of grass allergen peptides versus placebo in patients with grass pollen-induced allergy (18-65 years). After a 4-day baseline challenge to rye grass in the environmental exposure unit (EEU), subjects were randomized to receive grass allergen peptides at 6 nmol at 2-week intervals for a total of 8 doses (8x6Q2W), grass allergen peptides at 12 nmol at 4-week intervals for a total of 4 doses (4x12Q4W), or grass allergen peptides at 12 nmol at 2-week intervals for a total of 8 doses (8x12Q2W) or placebo and treated before the grass pollen season. The primary efficacy end point was change from baseline in total rhinoconjunctivitis symptom score across days 2 to 4 of a 4-day posttreatment challenge (PTC) in the EEU after the grass pollen season. Secondary efficacy end points and safety were also assessed. Two hundred eighty-two subjects were randomized. Significantly greater improvement (reduction of total rhinoconjunctivitis symptom score from baseline to PTC) occurred across days 2 to 4 with grass allergen peptide 8x6Q2W versus placebo (-5.4 vs -3.8, respectively; P = .0346). Greater improvement at PTC also occurred for grass allergen peptide 8x6Q2W versus placebo (P = .0403) in patients with more symptomatic ARC. No safety signals were detected. Grass allergen peptide 8x6Q2W significantly improved ARC symptoms after rye grass allergen challenge in an EEU with an acceptable safety profile. Copyright © 2017 American Academy of Allergy, Asthma & Immunology

  4. Influence of soil organisms on accuracy predicting leaf litter ...

    African Journals Online (AJOL)

    To use Near Infrared Spectroscopy (NIRS) in the study of litter decomposition in field conditions, it's essential to know the relative role of different environmental factors that may affect its accuracy. This study attempts to determine the effects of soil organisms on direct predicting by NIRS, the stage of litter decomposition, ...

  5. Influence of Tree Characters and Climate on Litter Characteristics in ...

    African Journals Online (AJOL)

    Litter production and decomposition rates have great importance in maintaining the fertility of the soil. The study was carried out to determine the relationship tree characters (girth size, canopy radius, tree height, leaf area and number of primary branches), litter production and quality, and climatic variables among stands of ...

  6. Decomposition of Cassava and Vegetable Cowpea leaf litters under ...

    African Journals Online (AJOL)

    Two related studies using three leaf residue types' cassava and vegetable cowpea leaves were carried out in the field and under controlled laboratory conditions to determine the rate of their decomposition using litter bag technique. The carbon dioxide evolution by the three leaf residues namely, Oven dry leaf litter, fresh ...

  7. THE FATE OF TANNINS IN CORSICAN PINE LITTER

    NARCIS (Netherlands)

    Nierop, K.G.J.; Verstraten, J.M.

    2006-01-01

    Tannins are ubiquitous in higher plants and therefore also in litter and soils where they affect many biogeochemical processes. Despite this well recognized role, the fate of tannins in litter and mineral soils is hardly known as often only trace amounts, if any, of tannins are measured. In this

  8. Use of natural zeolite-supplemented litter increased broiler production

    African Journals Online (AJOL)

    The aim of this study was to ascertain the influence of natural zeolite, consisting mainly of clinoptilolite and mordenite, as a component of the litter material in broiler houses on the performance of the broilers and on some litter characteristics. Live weight gain, feed consumption, feed efficiency, viability and leg and body ...

  9. Use of natural zeolite-supplemented litter increased broiler production

    African Journals Online (AJOL)

    smyo

    Abstract. The aim of this study was to ascertain the influence of natural zeolite, consisting mainly of clinoptilolite and mordenite, as a component of the litter material in broiler houses on the performance of the broilers and on some litter characteristics. Live weight gain, feed consumption, feed efficiency, viability and leg and ...

  10. The emission of volatile compounds from leaf litter

    NARCIS (Netherlands)

    Derendorp, L.

    2012-01-01

    Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the

  11. Specific leaf area predicts dryland litter decomposition via two mechanisms

    NARCIS (Netherlands)

    Liu, Guofang; Wang, Lei; Jiang, Li; Pan, Xu; Huang, Zhenying; Dong, Ming; Cornelissen, Johannes H.C.

    2018-01-01

    Litter decomposition plays important roles in carbon and nutrient cycling. In dryland, both microbial decomposition and abiotic degradation (by UV light or other forces) drive variation in decomposition rates, but whether and how litter traits and position determine the balance between these

  12. Marine litter monitoring by northern fulmars: progress report 2002

    NARCIS (Netherlands)

    Franeker, van J.A.; Meijboom, A.

    2003-01-01

    An earlier pilot study on litter contents in stomachs of Fulmars indicated that this seabird can be used as a suitable indicator for levels of marine litter pollution on the North Sea off the Dutch coast. This progress report updates the existing dataset with data on Fulmar stomach contents in the

  13. Mangrove litter production and organic carbon pools in the ...

    African Journals Online (AJOL)

    Mngazana Estuary is an important source of mangrove litter and POC for the adjacent marine environment, possibly sustaining nearshore food webs. Keywords: Dissolved organic carbon, harvesting, litter production, mangroves, particulate organic carbon, Rhizophora mucronata, South Africa African Journal of Aquatic ...

  14. Record Litter Size for the Bull Shark, Carcharhinus leucas (Muller ...

    African Journals Online (AJOL)

    Review of the authoritative compendia and literature that inform these databases (Bass et al., 1973, Garrick, 1982, Compagno, 1984, Fowler et al., 2005) confirmed this maximum litter size but indicated that the majority of litters number between 6-8 pups. Furthermore, the upper limit of 13 pups comes from a single reference ...

  15. Evaluation of Some Litter Traits and Heritability Estimates of ...

    African Journals Online (AJOL)

    SH

    Balogun (1981) reported that pigs possess several advantages over other livestock species. They have higher prolificacy than cattle, sheep and goat, and are capable of producing 4 to 5 litters with an average of seven piglets per litter in two years. They mate early and have shorter generation interval than red meat animals.

  16. Effects of adding aluminum sulfate to different litters on selected ...

    African Journals Online (AJOL)

    The objective of this study was to determine the effects of adding aluminum sulfate to different litters on blood plasma concentrations of some principal microelements and some vitamins in broilers. In this experiment, 645 day old Ross 308 broiler chicks were randomly divided into 4 litter group (straw, sawdust, alum ...

  17. Analysis of litter mesofauna of Poltava region forest ecosystems

    Directory of Open Access Journals (Sweden)

    O. S. Komarov

    2007-08-01

    Full Text Available On the basis of research of litter mesofauna of 48 forest biogeocenoses the regularities of invertebrate communities formation on the species and families levels are determined. The degree of similarity of test plots are analysed by taxonomic structure of the communities. The factors of the litter invertebrate communities formation in forest ecosystems of the Poltava region are revealed.

  18. Influence of breed and environmental factors on litter parameters of ...

    African Journals Online (AJOL)

    The influence of breed and environmental factors such as season, temperature, relative humidity, sunshine hours and wind speed on litter parameters of rabbits raised in a semi-humid environment was investigated using two hundred and twenty four (224) litter records collected between 1991 and 1997. New Zealand White ...

  19. Street littering in Nigerian towns: towards framework for sustainable ...

    African Journals Online (AJOL)

    An aspect of solid waste management that has become almost intractable to local authorities in Nigeria is street littering. In a study carried out across the country in April/May 2008, this paper tried to expose some of the major factors that contribute to street littering. Six thousand subjects living along 120 streets (6 streets per ...

  20. Characterization of Forest Structure and an Assessment of Litter ...

    African Journals Online (AJOL)

    Nafiisah

    Many studies have cited mangroves as being among the most productive ecosystems of the world in terms of gross primary productivity and litter turnover, which forms a major food source for most estuarine animals. The present study aimed at characterizing the forest structure and assessing litter production, accumulation ...

  1. Estimate of genetic and phenotypic parameters for litter size and ...

    African Journals Online (AJOL)

    Data on 964 and 1150 weaning weight and litter size records respectively, collected over a 10-year period on Yankasa Sheep breeding project at the National Animal Production Research Institute (N.A.P.R.I.), Zaria, were used in this study. The analysis was for estimation of genetic and phenotypic parameters for litter size ...

  2. Litter in submarine canyons off the west coast of Portugal

    Science.gov (United States)

    Mordecai, Gideon; Tyler, Paul A.; Masson, Douglas G.; Huvenne, Veerle A. I.

    2011-12-01

    Marine litter is of global concern and is present in all the world's oceans, including deep benthic habitats where the extent of the problem is still largely unknown. Litter abundance and composition were investigated using video footage and still images from 16 Remotely Operated Vehicle (ROV) dives in Lisbon, Setúbal, Cascais and Nazaré Canyons located west of Portugal. Litter was most abundant at sites closest to the coastline and population centres, suggesting the majority of the litter was land sourced. Plastic was the dominant type of debris, followed by fishing gear. Standardised mean abundance was 1100 litter items km -2, but was as high as 6600 litter items km -2 in canyons close to Lisbon. Although all anthropogenic material may be harmful to biota, debris was also used as a habitat by some macro-invertebrates. Litter composition and abundance observed in the canyons of the Portuguese margin were comparable to those seen in other deep sea areas around the world. Accumulation of litter in the deep sea is a consequence of human activities both on land and at sea. This needs to be taken into account in future policy decisions regarding marine pollution.

  3. Marine Litter, Eutrophication and Noise Assessment Tools

    Science.gov (United States)

    Palazov, Atanas; Velcheva, Maya; Milkova, Tanya; Slabakova, Violeta; Marinova, Veselka

    2017-04-01

    MARLEN - Marine Litter, Eutrophication and Noise Assessment Tools is a project under the Programme BG02.03: Increased capacity for assessing and predicting environmental status in marine and inland waters, managed by Bulgarian Ministry of environment and waters and co-financed by the Financial Mechanism of the European Economic Area (EEA FM) 2009 - 2014. Project Beneficiary is the Institute of oceanology - Bulgarian Academy of Sciences with two partners: Burgas municipality and Bulgarian Black Sea Basin Directorate. Initial assessment of ecological state of Bulgarian marine waters showed lack of data for some descriptors of MSFD. The main goal of MARLEN is to build up tools for assessment of marine environment by implementing new technologies and best practices for addressing three main areas of interest with lack of marine data in particular: a) Marine litter detection and classification in coastal areas; b) Regular near real time surface water eutrophication monitoring on large aquatory; c) Underwater noise monitoring. Developed tools are an important source of real time, near real time and delay mode marine data for Bulgarian Black Sea waters. The partnership within the project increased capacity for environmental assessments and training of personnel and enhances collaboration between scientific institutes, regional and local authorities. Project results supported implementation of MSFD in Bulgarian marine waters for the benefit of coastal population, marine industry, tourism, marine research and marine spatial planning.

  4. The influence of selected litter and herd factors on treatments for lameness in suckling piglets from 35 Danish herds

    DEFF Research Database (Denmark)

    Christensen, J.

    1996-01-01

    was: high-risk litters are (1) large litters, (2) litters with previous diseases or deaths, (3) litters where the nursing sow had been treated, or (4) litters from high-parity sows. Litters from large conventional herds or from herds with a high stocking density were expected to have a high risk...

  5. Microbial mineralization of organic nitrogen forms in poultry litters.

    Science.gov (United States)

    Rothrock, Michael J; Cook, Kimberly L; Warren, Jason G; Eiteman, Mark A; Sistani, Karamat

    2010-01-01

    Ammonia volatilization from the mineralization of uric acid and urea has a major impact on the poultry industry and the environment. Dry acids are commonly used to reduce ammonia emissions from poultry houses; however, little is known about how acidification affects the litter biologically. The goal of this laboratory incubation was to compare the microbiological and physiochemical effects of dry acid amendments (Al+Clear, Poultry Litter Treatment, Poultry Guard) on poultry litter to an untreated control litter and to specifically correlate uric acid and urea contents of these litters to the microbes responsible for their mineralization. Although all three acidifiers eventually produced similar effects within the litter, there was at least a 2-wk delay in the microbiological responses using Poultry Litter Treatment. Acidification of the poultry litter resulted in >3 log increases in total fungal concentrations, with both uricolytic (uric acid degrading) and ureolytic (urea degrading) fungi increasing by >2 logs within the first 2 to 4 wk of the incubation. Conversely, total, uricolytic, and ureolytic bacterial populations all significantly declined during this same time period. While uric acid and urea mineralization occurred within the first 2 wk in the untreated control litter, acidification resulted in delayed mineralization events for both uric acid and urea (2 and 4 wk delay, respectively) once fungal cell concentrations exceeded a threshold level. Therefore, fungi, and especially uricolytic fungi, appear to have a vital role in the mineralization of organic N in low-pH, high-N environments, and the activity of these fungi should be considered in best management practices to reduce ammonia volatilization from acidified poultry litter.

  6. Different techniques to study rumen fermentation characteristics of maturing grass and grass silage

    NARCIS (Netherlands)

    Cone, J.W.; Gelder, van A.H.; Soliman, I.A.; Visser, de H.; Vuuren, van A.M.

    1999-01-01

    Grass samples were harvested during the 1993 growing season after a precut on April 27, 1993 and were stored frozen or left to ensile in 30-L buckets. Effects on chemical composition and fermentation kinetics of the maturation of the grass and of ensiling were investigated. Chemical composition and

  7. Litter removal in a tropical rain forest reduces fine root biomass and production but litter addition has few effects.

    Science.gov (United States)

    Rodtassana, C; Tanner, E V J

    2018-03-01

    Many old-growth lowland tropical rain forests are potentially nutrient limited, and it has long been thought that many such forests maintain growth by recycling nutrients from decomposing litter. We investigated this by continuously removing (for 10 yr) freshly fallen litter from five (45 m × 45 m) plots, adding it to five other plots, there were five controls. From monthly measures over 1 yr we show that litter removal caused lower: fine root (≤2 mm diameter) standing mass, fine root standing length, fine root length production and fine root length survivorship. Litter addition did not significantly change fine root mass or length or production. Nutrient concentrations in fine roots in litter removal plots were lower than those in controls for nitrogen (N), calcium (Ca) and magnesium (Mg), concentrations in fine roots in litter addition plots were higher for N and Ca. Chronic litter removal has resulted in reduced forest growth due to lack of nutrients, probably nitrogen. Conversely, long-term litter addition has had fewer effects. © 2018 by the Ecological Society of America.

  8. Long-term effects of poultry litter, alum-treated litter, and ammonium nitrate on aluminium availability in soils

    NARCIS (Netherlands)

    Moore, P.A.; Edwards, D.

    2005-01-01

    Received for publication December 14, 2004. Research has shown that alum [Al2(SO4)3·14H2O] applications to poultry litter can greatly reduce phosphorus (P) runoff, as well as decrease ammonia (NH3) volatilization. However, the long-term effects of fertilizing with alum-treated litter are unknown.

  9. Negative impacts of invasive plants on conservation of sensitive desert wildlife

    Science.gov (United States)

    Drake, K. Kristina; Bowen, Lizabeth; Nussear, Kenneth E.; Esque, Todd C.; Berger, Andrew J.; Custer, Nathan; Waters, Shannon C.; Johnson, Jay D.; Miles, A. Keith; Lewison, Rebecca L.

    2016-01-01

    Habitat disturbance from development, resource extraction, off-road vehicle use, and energy development ranks highly among threats to desert systems worldwide. In the Mojave Desert, United States, these disturbances have promoted the establishment of nonnative plants, so that native grasses and forbs are now intermixed with, or have been replaced by invasive, nonnative Mediterranean grasses. This shift in plant composition has altered food availability for Mojave Desert tortoises (Gopherus agassizii), a federally listed species. We hypothesized that this change in forage would negatively influence the physiological ecology, immune competence, and health of neonatal and yearling tortoises. To test this, we monitored the effects of diet on growth, body condition, immunological responses (measured by gene transcription), and survival for 100 captive Mojave tortoises. Tortoises were assigned to one of five diets: native forbs, native grass, invasive grass, and native forbs combined with either the native or invasive grass. Tortoises eating native forbs had better body condition and immune functions, grew more, and had higher survival rates (>95%) than tortoises consuming any other diet. At the end of the experiment, 32% of individuals fed only native grass and 37% fed only invasive grass were found dead or removed from the experiment due to poor body conditions. In contrast, all tortoises fed either the native forb or combined native forb and native grass diets survived and were in good condition. Health and body condition quickly declined for tortoises fed only the native grass (Festuca octoflora) or invasive grass (Bromus rubens) with notable loss of fat and muscle mass and increased muscular atrophy. Bromus rubens seeds were found embedded in the oral mucosa and tongue in most individuals eating that diet, which led to mucosal inflammation. Genes indicative of physiological, immune, and metabolic functions were transcribed at lower levels for individuals fed B

  10. Control of invasive weeds with prescribed burning

    Science.gov (United States)

    DiTomaso, Joseph M.; Brooks, Matthew L.; Allen, Edith B.; Minnich, Ralph; Rice, Peter M.; Kyser, Guy B.

    2006-01-01

    Prescribed burning has primarily been used as a tool for the control of invasive late-season annual broadleaf and grass species, particularly yellow starthistle, medusahead, barb goatgrass, and several bromes. However, timely burning of a few invasive biennial broadleaves (e.g., sweetclover and garlic mustard), perennial grasses (e.g., bluegrasses and smooth brome), and woody species (e.g., brooms and Chinese tallow tree) also has been successful. In many cases, the effectiveness of prescribed burning can be enhanced when incorporated into an integrated vegetation management program. Although there are some excellent examples of successful use of prescribed burning for the control of invasive species, a limited number of species have been evaluated. In addition, few studies have measured the impact of prescribed burning on the long-term changes in plant communities, impacts to endangered plant species, effects on wildlife and insect populations, and alterations in soil biology, including nutrition, mycorrhizae, and hydrology. In this review, we evaluate the current state of knowledge on prescribed burning as a tool for invasive weed management.

  11. Mixing effects on litter decomposition rates in a young tree diversity experiment

    Science.gov (United States)

    Setiawan, Nuri Nurlaila; Vanhellemont, Margot; De Schrijver, An; Schelfhout, Stephanie; Baeten, Lander; Verheyen, Kris

    2016-01-01

    Litter decomposition is an essential process for biogeochemical cycling and for the formation of new soil organic matter. Mixing litter from different tree species has been reported to increase litter decomposition rates through synergistic effects. We assessed the decomposition rates of leaf litter from five tree species in a recently established tree diversity experiment on a post-agriculture site in Belgium. We used 20 different leaf litter compositions with diversity levels ranging from 1 up to 4 species. Litter mass loss in litterbags was assessed 10, 20, 25, 35, and 60 weeks after installation in the field. We found that litter decomposition rates were higher for high-quality litters, i.e., with high nitrogen content and low lignin content. The decomposition rates of mixed litter were more affected by the identity of the litter species within the mixture than by the diversity of the litter per se, but the variability in litter decomposition rates decreased as the litter diversity increased. Among the 15 different mixed litter compositions in our study, only three litter combinations showed synergistic effects. Our study suggests that admixing tree species with high-quality litter in post-agricultural plantations helps in increasing the mixture's early-stage litter decomposition rate.

  12. Uncharismatic Invasives

    Directory of Open Access Journals (Sweden)

    Clark, Jonathan L.

    2015-05-01

    Full Text Available Although philosophers have examined the ethics of invasive species management, there has been little research approaching this topic from a descriptive, ethnographic perspective. In this article I examine how invasive species managers think about the moral status of the animals they seek to manage. I do so through a case study of Oregon’s efforts to manage the invasive species that are rafting across the Pacific attached to tsunami debris in the wake of the Japanese tsunami of 2011. Focusing on the state’s response to a dock that washed ashore on Agate Beach with various marine invertebrates attached to it, I argue that these animals’ position on two intersecting scales of moral worth—the sociozoologic scale and the phylogenetic scale—rendered them unworthy of moral consideration.

  13. Determinants of flammability in savanna grass species.

    Science.gov (United States)

    Simpson, Kimberley J; Ripley, Brad S; Christin, Pascal-Antoine; Belcher, Claire M; Lehmann, Caroline E R; Thomas, Gavin H; Osborne, Colin P

    2016-01-01

    Tropical grasses fuel the majority of fires on Earth. In fire-prone landscapes, enhanced flammability may be adaptive for grasses via the maintenance of an open canopy and an increase in spatiotemporal opportunities for recruitment and regeneration. In addition, by burning intensely but briefly, high flammability may protect resprouting buds from lethal temperatures. Despite these potential benefits of high flammability to fire-prone grasses, variation in flammability among grass species, and how trait differences underpin this variation, remains unknown.By burning leaves and plant parts, we experimentally determined how five plant traits (biomass quantity, biomass density, biomass moisture content, leaf surface-area-to-volume ratio and leaf effective heat of combustion) combined to determine the three components of flammability (ignitability, sustainability and combustibility) at the leaf and plant scales in 25 grass species of fire-prone South African grasslands at a time of peak fire occurrence. The influence of evolutionary history on flammability was assessed based on a phylogeny built here for the study species.Grass species differed significantly in all components of flammability. Accounting for evolutionary history helped to explain patterns in leaf-scale combustibility and sustainability. The five measured plant traits predicted components of flammability, particularly leaf ignitability and plant combustibility in which 70% and 58% of variation, respectively, could be explained by a combination of the traits. Total above-ground biomass was a key driver of combustibility and sustainability with high biomass species burning more intensely and for longer, and producing the highest predicted fire spread rates. Moisture content was the main influence on ignitability, where species with higher moisture contents took longer to ignite and once alight burnt at a slower rate. Biomass density, leaf surface-area-to-volume ratio and leaf effective heat of combustion

  14. Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter

    Science.gov (United States)

    Stohlgren, Thomas J.

    1988-01-01

    The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p r2 = 0.92, p r2 = 0.80, p < 0.05). Patterns of nutrient release were highly variable. Giant sequoia immobilized N and P, incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.

  15. Decomposition, nitrogen and phosphorus mineralization from beech leaf litter colonized with ectomycorrhizal or litter decomposing basidiomycetes

    OpenAIRE

    COLPAERT, Jan; VAN TICHELEN, Katia

    1996-01-01

    The decomposition and the nitrogen and phosphorus mineralization of fresh beech (Fagus sylvatica L.) leaf litter are described. Leaves were buried for up to 6 months in plant containers in which Scots pine (Pinus sylvestris L.) seedlings were cultivated at a low rate of nutrient addition. The saprotrophic abilities of three ectomycorrhizal fungi, Thelephora terrestris Ehrh.: Fr., Suillus bovinus (L.: Fr.) O. Kuntze and Paxillus involutes (Batsch: Fr) Fr., were compared with the degradation ca...

  16. Resilience to stress and disturbance, and resistance to Bromus tectorum LBromus tectorum L. invasion in cold desert shrublands of western North America

    Science.gov (United States)

    Jeanne C. Chambers; Bethany A. Bradley; Cynthia S. Brown; Carla D' Antonio; Matthew J. Germino; James B. Grace; Stuart P. Hardegree; Richard F. Miller; David A. Pyke

    2014-01-01

    Alien grass invasions in arid and semi-arid ecosystems are resulting in grass-fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine...

  17. Effect of mountain climatic elevation gradient and litter origin on decomposition processes: long-term experiment with litter-bags

    Science.gov (United States)

    Klimek, Beata; Niklińska, Maria; Chodak, Marcin

    2013-04-01

    Temperature is one of the most important factors affecting soil organic matter decomposition. Mountain areas with vertical gradients of temperature and precipitation provide an opportunity to observe climate changes similar to those observed at various latitudes and may serve as an approximation for climatic changes. The aim of the study was to compare the effects of climatic conditions and initial properties of litter on decomposition processes and thermal sensitivity of forest litter. The litter was collected at three altitudes (600, 900, 1200 m a.s.l.) in the Beskidy Mts (southern Poland), put into litter-bags and exposed in the field since autumn 2011. The litter collected at single altitude was exposed at the altitude it was taken and also at the two other altitudes. The litter-bags were laid out on five mountains, treated as replicates. Starting on April 2012, single sets of litter-bags were collected every five weeks. The laboratory measurements included determination of dry mass loss and chemical composition (Corg, Nt, St, Mg, Ca, Na, K, Cu, Zn) of the litter. In the additional litter-bag sets, taken in spring and autumn 2012, microbial properties were measured. To determine the effect of litter properties and climatic conditions of elevation sites on decomposing litter thermal sensitivity the respiration rate of litter was measured at 5°C, 15°C and 25°C and calculated as Q10 L and Q10 H (ratios of respiration rate between 5° and 15°C and between 15°C and 25°C, respectively). The functional diversity of soil microbes was measured with Biolog® ECO plates, structural diversity with phospholipid fatty acids (PLFA). Litter mass lost during first year of incubation was characterized by high variability and mean mass lost ranged up to a 30% of initial mass. After autumn sampling we showed, that mean respiration rate of litter (dry mass) from the 600m a.s.l site exposed on 600m a.s.l. was the highest at each tested temperature. In turn, the lowest mean

  18. Size dependent differences in litter consumption of isopods: preliminary results

    Directory of Open Access Journals (Sweden)

    Ferenc Vilisics

    2012-03-01

    Full Text Available A series of experiments were applied to test how leaf orientation within microcosms affect consumption rates (Experiment 1, and to discover intra-specific differences in leaf litter consumption (Experiment 2 of the common isopod species Porcellio scaber and Porcellionides pruinosus. A standardised microcosm setup was developed for feeding experiments to maintain standard conditions. A constant amount of freshly fallen black poplar litter was provided to three distinct size class (small, medium, large of woodlice. We measured litter consumption after a fortnight. We maintained appr. constant isopod biomass for all treatments, and equal densities within each size class. We hypothesized that different size classes differ in their litter consumption, therefore such differences should occur even within populations of the species. We also hypothesized a marked difference in consumption rates for different leaf orientation within microcosms. Our results showed size-specific consumption patterns for P. scaber: small adults showed the highest consumption rates (i.e. litter mass loss / isopod biomass in high density microcosms, while medium-sized adults of lower densities ate the most litter in containers. Leaf orientation posed no significant effect on litter consumption.

  19. Public perspective towards marine litter in West Aceh City

    Science.gov (United States)

    Kusumawati, I.; Setyowati, M.; Riana, E.; Prartono, T.

    2018-03-01

    Marine litter or marine debris is a man-made solid material discarded, abandoned or lost in coastline or into the sea. To reduce the amount of marine litter in the ocean, raising public awareness is an important way. One of the contributing factors on marine litter is the lack of understanding within the community, but to identify how people notice the problem is required adequate research literature. The purpose of this study is to examine the awareness of West Aceh community on marine litter along western coastal area. The research objectives; 1) to evaluate societal perception towards marine litter; 2) to examine the urgent indicator of public awareness in West Aceh City. This study will employ a survey approach by distributing questionnaires to 383 respondents. It was found that respondents show low awareness on marine litter according to statistical data, but there are some rooms to manage in order to raise the level of public awareness. It concludes that sense of responsibility could be enhanced by involving public in any activities for preventing and eradicating marine litter. Education aspect is also important to increase public understanding about the threats of marine debris on environment, human health and economic income.

  20. Influence of Covering Reused Broiler Litter with Plastic Canvas on Litter Characteristics and Bacteriology and the Subsequent Immunity and Microbiology of Broilers

    Directory of Open Access Journals (Sweden)

    D Mesa

    Full Text Available ABSTRACT In broiler production, the litter is reused for consecutives flocks, and it is treated during down time between flocks to reduce its microbial load. Although covering the litter with a plastic canvas is a common litter treatment in the field, there is little scientific information available on its efficacy. The aim of this study was to evaluate the effects of covering broiler litter with a plastic canvas for eight days on litter microbiological, physical, and chemical parameters, and on the intestinal microbiota and immunity of broilers. In the first trial, reused litter from a previous flock was distributed into three treatments, with six replicates each: L1 (negative control, litter free from Salmonella Enteritidis (SE and Eimeria maxima (EM and not covered, L2 (positive control, litter with SE and EM, and not covered, and L3 (litter with SE and EM, and covered with plastic canvas for eight days. Litter total bacteria, Enterobacteria, Lactobacillus, SE, and EM counts, and litter pH, temperature, moisture, and ammonia emission were determined on days 1 and 8. In the second trial, broilers were housed on those litters according to the treatments described above, and their intestinal microbiota, gut CD4+ and CD8+ lymphocytes and macrophages, and liver and intestinal pro-inflammatory interleukin (IFN-γ, IL-1β e IL-18 levels were evaluated on days 14 and 28. A significant reduction of litter bacterial populations was observed in the litter covered with plastic canvas. A significantly higher mRNA IFN-γ gene expression (12.5-fold was observed in the jejunum and liver of broilers reared on the litter with Enterobacteria counts. No EM reduction was observed in the covered litter. Covering reused broiler litter with plastic canvas reduces initial litter bacterial load as a result of the interaction between physical and chemical parameters.

  1. Role of carbohydrate metabolism in grass tetany

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.K.; Madsen, F.C.; Lentz, D.E.; Hansard, S.L.

    1977-01-01

    Clinical hypomagnesemia is confined primarily to beef cattle in the United States but also occurs in dairy cattle in other countries, probably due to different management practices. During periods when grass tetany is likely, early vegetative temperate zone grasses are usually low in total readily available carbohydrates and magnesium but high in potassium and nitrogen. The tetany syndrome may include hypoglycemia and ketosis, suggesting an imbalance in intermediary energy metabolism. Many enzyme systems critical to cellular metabolism, including those which hydrolyze and transfer phosphate groups, are activated by Mg. Thus, by inference, Mg is required for normal glucose utilization, fat, protein, nucleic acid and coenzyme synthesis, muscle contraction, methyl group transfer, and sulfate, acetate, and formate activation. Numerous clinical and experimental studies suggest an intimate relationship between metabolism of Mg and that of carbohydrate, glucagon, and insulin. The objective is to review this literature and suggest ways in which these relationships might contribute to a chain of events leading to grass tetany.

  2. Grass Biomethane for Agriculture and Energy

    DEFF Research Database (Denmark)

    Korres, N.E.; Thamsiriroj, T.; Smith, B.

    2011-01-01

    Many factors enforce the intensification of grassland utilization which is associated with significant environmental impacts subjected to various legislative constraints. Nevertheless, the need for diversification in agricultural production and the sustainability in energy within the European Union...... have advanced the role of grassland as a renewable source of energy in grass biomethane production with various environmental and socio-economic benefits. It is underlined that the essential question whether the gaseous biofuel meets the EU sustainability criteria of 60% greenhouse gas emission savings...... by 2020 can be met since savings up to 89.4% under various scenarios can be achieved. Grass biomethane production compared to other liquid biofuels either when these are produced by indigenous of imported feedstocks is very promising. Grass biomethane, given the mature and well known technology...

  3. Grass pollen immunotherapy: where are we now.

    Science.gov (United States)

    Würtzen, Peter A; Gupta, Shashank; Brand, Stephanie; Andersen, Peter S

    2016-01-01

    During allergen immunotherapy (AIT), the allergic patient is exposed to the disease-inducing antigens (allergens) in order to induce clinical and immunological tolerance and obtain disease modification. Large trials of grass AIT with highly standardized subcutaneous and sublingual tablet vaccines have been conducted to document the clinical effect. Induction of blocking antibodies as well as changes in the balance between T-cell phenotypes, including induction of regulatory T-cell subtypes, have been demonstrated for both treatment types. These observations increase the understanding of the immunological mechanism behind the clinical effect and may make it possible to use the immunological changes as biomarkers of clinical effect. The current review describes the recent mechanistic findings for subcutaneous immunotherapy and sublingual immunotherapy/tablet treatment and discusses how the observed immunological changes translate into a scientific foundation for the observed clinical effects of grass pollen immunotherapy and lead to new treatment strategies for grass AIT.

  4. Biogas and Methane Yield from Rye Grass

    Directory of Open Access Journals (Sweden)

    Tomáš Vítěz

    2015-01-01

    Full Text Available Biogas production in the Czech Republic has expanded substantially, including marginal regions for maize cultivation. Therefore, there are increasingly sought materials that could partially replace maize silage, as a basic feedstock, while secure both biogas production and its quality.Two samples of rye grass (Lolium multiflorum var. westerwoldicum silage with different solids content 21% and 15% were measured for biogas and methane yield. Rye grass silage with solid content of 15% reached an average specific biogas yield 0.431 m3·kg−1 of organic dry matter and an average specific methane yield 0.249 m3·kg−1 of organic dry matter. Rye grass silage with solid content 21% reached an average specific biogas yield 0.654 m3·kg−1 of organic dry matter and an average specific methane yield 0.399 m3·kg−1 of organic dry matter.

  5. Ammonia and nitrous oxide emissions from broiler houses with downtime windrowed litter

    Science.gov (United States)

    An emerging poultry manure management practice is in house windrowing to disinfect the litter. With this practice, growers windrow the litter in broiler houses between flocks, usually for 2 weeks. This results in high litter temperatures that can reduce pathogens in the litter. However, this practi...

  6. Cesium-137 in grass from Chernobyl fallout

    International Nuclear Information System (INIS)

    Papastefanou, C.; Manolopoulou, M.; Stoulos, S.; Ioannidou, A.; Gerasopoulos, E.

    2005-01-01

    Grass ecosystem was monitored for 137 Cs, a relatively long-lived radionuclide, for about 16 years since the Chernobyl reactor accident occurred on April 26, 1986. Cesium-137 in grass gramineae or poaceae the species, ranged from 122.9 Bq kg -1 (September 4, 1986) to 5.8 mBq kg -1 (October 16, 2001) that is a range of five orders of magnitude. It was observed that there was a trend of decreasing 137 Cs with time reflecting a removal half-time of 40 months (3 1/3 years), which is the ecological half-life, T ec of 137 Cs in grassland

  7. Clover-grass as an energy crop

    International Nuclear Information System (INIS)

    1996-11-01

    Breeding of clover grass on fallow areas as a resource for methane generation has several important advantages. It does not require any additional nitrogen fertilizer as it can fix the atmospheric nitrogen.Herbicides are unnecessary as most weeds are one-year plants, while clover is perennial. From methane generation data for clover-grass the gross energy generation has been calculated to 11.08 MJ per kg dry matter. Net energy generation (with account for electric power) is calculated to 14.00 MJ/kg dry matter. (EG)

  8. Distinct physiological responses underlie defoliation tolerance in African lawn and bunch grasses

    NARCIS (Netherlands)

    Anderson, T.M.; Kumordzi, B.B.; Fokkema, W.; Valls Fox, H.; Olff, H.

    Premise of research. African grass communities are dominated by two distinct functional types: tall, caespitose bunch grasses and short, spreading lawn grasses. Functional type coexistence has been explained by differences in defoliation tolerance, because lawn grasses occur in intensively grazed

  9. Modelling of excess noise attnuation by grass and forest | Onuu ...

    African Journals Online (AJOL)

    , guinea grass (panicum maximum) and forest which comprises iroko (milicia ezcelea) and white afara (terminalia superba) trees in the ratio of 2:1 approximately. Excess noise attenuation spectra have been plotted for the grass and forest for ...

  10. Wildlife Habitat Quality (Sward Structure and Ground Cover Response of Mixed Native Warm-Season Grasses to Harvesting

    Directory of Open Access Journals (Sweden)

    Vitalis W. Temu

    2014-08-01

    Full Text Available Agricultural intensification in America has replaced native warm-season grasses (NWSG with introduced forages causing wildlife habitat loss and population declines for the northern bobwhite (Colinus virginianus and similar ground-nesting birds. Reintroducing NWSGs onto managed grasslands to reverse grassland bird population declines lacks information about appropriate multi-purpose management. Post-season nesting habitat quality of mixed NWSGs (indiangrass (IG, Sorghastrum nutans, big bluestem (BB, Andropogon gerardii and little bluestem (LB, Schizachyrium scoparium responding to previous-year(s harvest intervals (treatments, 30-, 40-, 60-, 90 or 120-d and duration (years in production, were assessed on late-spring-early-summer re-growths. Yearly phased harvestings were initiated in May on sets of randomized plots, ≥90-cm apart, in five replications (blocks to produce one-, two-, and three-year old stands by the third year. Sward heights and canopy closure were recorded a day before harvest, followed a week after by visual estimates of ground cover of plant species and litter. Harvesting increased post-season grass cover and reduced forbs following a high rainfall year. Harvested plot swards showed no treatment differences, but were shorter and intercepted more sunlight. Similarly, harvest duration increased grass cover with no year effect but reduced forbs following a high rainfall year. One- or two-year full-season harvesting of similar stands may not compromise subsequent bobwhite nesting-cover provided post-season harvesting starts after the breeding cycle is completed.

  11. Plastic traits of an exotic grass contribute to its abundance but are not always favourable.

    Directory of Open Access Journals (Sweden)

    Jennifer Firn

    Full Text Available In herbaceous ecosystems worldwide, biodiversity has been negatively impacted by changed grazing regimes and nutrient enrichment. Altered disturbance regimes are thought to favour invasive species that have a high phenotypic plasticity, although most studies measure plasticity under controlled conditions in the greenhouse and then assume plasticity is an advantage in the field. Here, we compare trait plasticity between three co-occurring, C(4 perennial grass species, an invader Eragrostis curvula, and natives Eragrostis sororia and Aristida personata to grazing and fertilizer in a three-year field trial. We measured abundances and several leaf traits known to correlate with strategies used by plants to fix carbon and acquire resources, i.e. specific leaf area (SLA, leaf dry matter content (LDMC, leaf nutrient concentrations (N, C:N, P, assimilation rates (Amax and photosynthetic nitrogen use efficiency (PNUE. In the control treatment (grazed only, trait values for SLA, leaf C:N ratios, Amax and PNUE differed significantly between the three grass species. When trait values were compared across treatments, E. curvula showed higher trait plasticity than the native grasses, and this correlated with an increase in abundance across all but the grazed/fertilized treatment. The native grasses showed little trait plasticity in response to the treatments. Aristida personata decreased significantly in the treatments where E. curvula increased, and E. sororia abundance increased possibly due to increased rainfall and not in response to treatments or invader abundance. Overall, we found that plasticity did not favour an increase in abundance of E. curvula under the grazed/fertilized treatment likely because leaf nutrient contents increased and subsequently its' palatability to consumers. E. curvula also displayed a higher resource use efficiency than the native grasses. These findings suggest resource conditions and disturbance regimes can be manipulated to

  12. Effects of nutrient enrichment on mangrove leaf litter decomposition

    NARCIS (Netherlands)

    Keuskamp, Joost A; Hefting, Mariet M; Dingemans, Bas J J; Verhoeven, Jos T A; Feller, Ilka C

    2015-01-01

    Nutrient enrichment of mangroves, a common phenomenon along densely populated coastlines, may negatively affect mangrove ecosystems by modifying internal carbon and nutrient cycling. The decomposition of litter exerts a strong influence on these processes and is potentially modified by

  13. A test of the hierarchical model of litter decomposition

    NARCIS (Netherlands)

    Bradford, Mark A.; Veen, Ciska G.F.; Bonis, Anne; Bradford, Ella M.; Classen, Aimee T.; Cornelissen, J.H.C.; Crowther, T.W.; Long, de Jonathan R.; Freschet, Gregoire T.; Kardol, Paul; Manrubia-Freixa, Marta; Maynard, Daniel S.; Newman, Gregory S.; Logtestijn, Richard S.P.; Viketoft, Maria; Wardle, David A.; Wieder, William R.; Wood, Stephen A.; Putten, van der Wim H.

    2017-01-01

    Our basic understanding of plant litter decomposition informs the assumptions underlying widely applied soil biogeochemical models, including those embedded in Earth system models. Confidence in projected carbon cycle–climate feedbacks therefore depends on accurate knowledge about the controls

  14. A test of the hierarchical model of litter decomposition

    NARCIS (Netherlands)

    Bradford, Mark A.; Ciska, G. F.; Bonis, Anne; Bradford, Ella M.; Classen, Aimee T.; Cornelissen, J. Hans C.; Crowther, Thomas W.; De Long, Jonathan R.; Freschet, Gregoire T.; Kardol, Paul; Manrubia-Freixa, Marta; Maynard, Daniel S.; Newman, Gregory S.; Logtestijn, Richard S.P.; Viketoft, Maria; Wardle, David A.; Wieder, William R.; Wood, Stephen A.; Van Der Putten, Wim H.

    2017-01-01

    Our basic understanding of plant litter decomposition informs the assumptions underlying widely applied soil biogeochemical models, including those embedded in Earth system models. Confidence in projected carbon cycle-climate feedbacks therefore depends on accurate knowledge about the controls

  15. Effects of invasive plants on arthropods.

    Science.gov (United States)

    Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

    2014-12-01

    Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to

  16. Names of Southern African grasses: Name changes and additional ...

    African Journals Online (AJOL)

    The main reasons for changes in botanical names are briefly reviewed, with examples from the lists. At this time, about 1040 grass species and subspecific taxa are recognized in the subcontinent. Keywords: botanical research; botanical research institute; botany; grass; grasses; identification; name change; nomenclature; ...

  17. Germination of Themeda triandra (Kangaroo grass) as affected by ...

    African Journals Online (AJOL)

    Low rainfall in range areas restricts germination, growth and development of majority of range grasses. However, germination and establishment potential of forage grasses vary and depends on environmental conditions. Themeda triandra is an excellent known grass to grow under different environmental conditions.

  18. A new grass frog from Namibia

    African Journals Online (AJOL)

    A new species of grass frog of the genus Ptychadena is described from northern Namibia. Although superficially similar to Ptychadena schilJukorum and Ptychadsna mossambica. the new species differs In advenisemen1 call, and erlernal charaders. An examination of a series of published sonagrams indicates.

  19. Grass Pollen Pollution from Biofuels Farming

    Czech Academy of Sciences Publication Activity Database

    Ratajová, A.; Tříska, Jan; Vrchotová, Naděžda; Kolář, L.; Kužel, S.

    2013-01-01

    Roč. 26, č. 4 (2013), s. 199-203 ISSN 2151-321X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : grass pollen pollution * biofuel s farming * temperate climate * PK-fertilization * N-fertilization * phenolic Subject RIV: EH - Ecology, Behaviour Impact factor: 0.556, year: 2013

  20. Notes on Alien Bromus Grasses in Taiwan

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jung

    2006-06-01

    Full Text Available Bromus carinatus Hook. & Arn., Bromus hordeaceus L., Bromus pubescens Muhl. ex Willd. and Bromus secalinus L. were recently found at middle elevations of southern and central Taiwan, respectively. We present taxonomic treatments, distribution map, and line-drawings of these introduced alien brome grasses.

  1. MoDest GrassUp

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Nyholm; S. Nadimi, Esmaeil

    2010-01-01

    The Technology The technology is one of a kind, as there is no such mathematical model estimating animal feed uptake available today. The estimation of grass uptake, is based on real time wireless sensor data, cow merit and climate data. Relevant cow behaviour data (such as location, movement vel...

  2. Grass Biomethane for Agriculture and Energy

    DEFF Research Database (Denmark)

    Korres, N.E.; Thamsiriroj, T.; Smith, B.

    2011-01-01

    have advanced the role of grassland as a renewable source of energy in grass biomethane production with various environmental and socio-economic benefits. It is underlined that the essential question whether the gaseous biofuel meets the EU sustainability criteria of 60% greenhouse gas emission savings...

  3. Effect of prenatal irradiation on total litter birth weight

    International Nuclear Information System (INIS)

    Angleton, G.M.; Lee, A.C.

    1981-01-01

    Total litter weight at birth was used as a response variable to study the effects of in utero irradiations on birth weight. Analyses were performed in such a manner as to allow for variations in litter size and environmental temperatures. No effects due to irradiation were noted for exposures given 8 days postcoitus (dpc) and 55 dpc. However, for exposures given 28 dpc, a 5% decrement in birth weight was found for an 80 rad dose

  4. SLAUGHTERING TRAITS OF PIGS REARED CONVENTIONALLY AND ON DEEP LITTER

    Directory of Open Access Journals (Sweden)

    Gordana Kralik

    2005-12-01

    Full Text Available The aim of this research was to compare slaughtering traits of two pig genotypes when reared in two different ways, and to determine the influence of pig housing on carcass characteristics and muscle tissue quality. The research was carried out on 68 fattening pigs of both sex, divided into two groups: the first group was kept on deep litter, and the second one was housed in flat deck pens without deep litter. Each group consisted of pigs of two genotypes, i.e. three-way crossbreeds of Large White and German Landrace (LW x GL in the dam line and of German Landrace and Pietrain (P in the sire line. At the end of the experiment, pigs were slaughtered and the following values were determined: the pH45 and pH24 values, electric conductivity values (EC45, EC24, the “a” and “b” carcass length, loin values and the values of backfat and muscle thickness, aiming to evaluate the share of muscular tissue in carcass by applying the two-points method. Pigs reared on deep litter had statistically significantly smaller live weights (P<0.05 and warm carcass weights in comparison to pigs reared on flat deck without deep litter. Pigs crossed with Pietrain, which were kept without deep litter had significantly thicker muscles than the ones crossed with German Landrace, kept on deep litter (P<0.05. Fattening pigs of both genotypes, reared without deep litter, had significantly smaller pH45 values in loins and in MLD, when compared to pigs crossed with Pietrain and kept on deep litter (P<0.05. The influence of genotype was statistically significant for the EC45 value in loin, as well as for the muscle thickness and percentage share of muscular tissue (P<0.05. Interaction between the way of fattening and genotype did not have any effect on carcass and meat quality.

  5. Invasive Species Mediate Insecticide Effects on Community and Ecosystem Functioning.

    Science.gov (United States)

    Rodrigues, Andreia C M; Machado, Ana L; Bordalo, Maria D; Saro, Liliana; Simão, Fátima C P; Rocha, Rui J M; Golovko, Oksana; Žlábek, Vladimír; Barata, Carlos; Soares, Amadeu M V M; Pestana, João L T

    2018-04-03

    Anthropogenic activities increase pesticide contamination and biological invasions in freshwater ecosystems. Understanding their combined effects on community structure and on ecosystem functioning presents challenges for an improved ecological risk assessment. This study focuses on an artificial stream mesocosms experiment testing for direct and indirect effects of insecticide (chlorantraniliprole - CAP) exposure on the structure of a benthic macroinvertebrate freshwater community and on ecosystem functioning (leaf decomposition, primary production). To understand how predator identity and resource quality alter the community responses to chemical stress, the mediating effects of an invasive predator species (crayfish Procambarus clarkii) and detritus quality (tested by using leaves of the invasive Eucalyptus globulus) on insecticide toxicity were also investigated. Low concentrations of CAP reduced the abundance of shredders and grazers, decreasing leaf decomposition and increasing primary production. Replacement of autochthonous predators and leaf litter by invasive species decreased macroinvertebrate survival, reduced leaf decomposition, and enhanced primary production. Structural equation modeling (SEM) highlighted that CAP toxicity to macroinvertebrates was mediated by the presence of crayfish or eucalypt leaf litter which are now common in many Mediterranean freshwaters. In summary, our results demonstrate that the presence of these two invasive species alters the effects of insecticide exposure on benthic freshwater communities. The approach used here also allowed for a mechanistic evaluation of indirect effects of these stressors and of their interaction on ecosystem functional endpoint, emphasizing the value of incorporating biotic stressors in ecotoxicological experiments.

  6. Consequences of biodiversity loss for litter decomposition across biomes.

    Science.gov (United States)

    Handa, I Tanya; Aerts, Rien; Berendse, Frank; Berg, Matty P; Bruder, Andreas; Butenschoen, Olaf; Chauvet, Eric; Gessner, Mark O; Jabiol, Jérémy; Makkonen, Marika; McKie, Brendan G; Malmqvist, Björn; Peeters, Edwin T H M; Scheu, Stefan; Schmid, Bernhard; van Ruijven, Jasper; Vos, Veronique C A; Hättenschwiler, Stephan

    2014-05-08

    The decomposition of dead organic matter is a major determinant of carbon and nutrient cycling in ecosystems, and of carbon fluxes between the biosphere and the atmosphere. Decomposition is driven by a vast diversity of organisms that are structured in complex food webs. Identifying the mechanisms underlying the effects of biodiversity on decomposition is critical given the rapid loss of species worldwide and the effects of this loss on human well-being. Yet despite comprehensive syntheses of studies on how biodiversity affects litter decomposition, key questions remain, including when, where and how biodiversity has a role and whether general patterns and mechanisms occur across ecosystems and different functional types of organism. Here, in field experiments across five terrestrial and aquatic locations, ranging from the subarctic to the tropics, we show that reducing the functional diversity of decomposer organisms and plant litter types slowed the cycling of litter carbon and nitrogen. Moreover, we found evidence of nitrogen transfer from the litter of nitrogen-fixing plants to that of rapidly decomposing plants, but not between other plant functional types, highlighting that specific interactions in litter mixtures control carbon and nitrogen cycling during decomposition. The emergence of this general mechanism and the coherence of patterns across contrasting terrestrial and aquatic ecosystems suggest that biodiversity loss has consistent consequences for litter decomposition and the cycling of major elements on broad spatial scales.

  7. Litter size variation in Polish selected small dog breeds

    Directory of Open Access Journals (Sweden)

    Małgorzata Goleman

    2015-08-01

    Full Text Available In breeders’ general opinion small breed females produce less numerous litters. The aim of the study was to analyse the litter size and the frequency of the gender ratio in selected small dog breeds in view of their popularity in Poland. The data set comprised information on 639 litters (in total 2578 puppies of eight breeds, which were born between January 2003 and end December 2014. The results were statistically analysed using statistical program SPSS 20.0. Medium-size litters were observed in the analysed small dog breeds (4.034±0.1. Comparison of the selected breeds of the Fédération Cynologique Internationale (FCI Groups showed that the mean litter size in Group IX was higher (4.36±0.08 than that in Group III (3.87±0.14 and the differences were statistically significant. The study has confirmed the hypothesis that larger females produce more numerous litters, but there are large intra-individual variations in the number of pups born in individual breeds. Additionally, the gender ratio in the puppies born in the analysed breeds was equal, despite the fluctuations in the individual breeds.

  8. Invertebrate grazers affect metal/metalloid fixation during litter decomposition.

    Science.gov (United States)

    Schaller, Jörg; Brackhage, Carsten

    2015-01-01

    Plant litter and organic sediments are main sinks for metals and metalloids in aquatic ecosystems. The effect of invertebrates as key species in aquatic litter decomposition on metal/metalloid fixation by organic matter is described only for shredders, but for grazers as another important animal group less is known. Consequently, a laboratory batch experiment was conducted to examine the effect of invertebrate grazers (Lymnaea stagnalis L.) on metal/metalloid fixation/remobilization during aquatic litter decomposition. It could be shown that invertebrate grazers facilitate significantly the formation of smaller sizes of particulate organic matter (POM), as shown previously for invertebrate shredders. The metal/metalloid binding capacity of these smaller particles of POM is higher compared to leaf litter residuals. But element enrichment is not as high as shown previously for the effect by invertebrate shredders. Invertebrate grazers enhance also the mobilization of selected elements to the water, in the range also proven for invertebrate shredders but different for the different elements. Nonetheless invertebrate grazers activity during aquatic litter decomposition leads to a metal/metalloid fixation into leaf litter as part of sediment organic matter. Hence, the effect of invertebrate grazers on metal/metalloid fixation/remobilization contrasts partly with former assessments revealing the possibility of an enhanced metal/metalloid fixation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Responses of the soil fungal communities to the co-invasion of two invasive species with different cover classes.

    Science.gov (United States)

    Wang, C; Zhou, J; Liu, J; Jiang, K; Xiao, H; Du, D

    2018-01-01

    Soil fungal communities play an important role in the successful invasion of non-native species. It is common for two or more invasive plant species to co-occur in invaded ecosystems. This study aimed to determine the effects of co-invasion of two invasive species (Erigeron annuus and Solidago canadensis) with different cover classes on soil fungal communities using high-throughput sequencing. Invasion of E. annuus and/or S. canadensis had positive effects on the sequence number, operational taxonomic unit (OTU) richness, Shannon diversity, abundance-based cover estimator (ACE index) and Chao1 index of soil fungal communities, but negative effects on the Simpson index. Thus, invasion of E. annuus and/or S. canadensis could increase diversity and richness of soil fungal communities but decrease dominance of some members of these communities, in part to facilitate plant further invasion, because high soil microbial diversity could increase soil functions and plant nutrient acquisition. Some soil fungal species grow well, whereas others tend to extinction after non-native plant invasion with increasing invasion degree and presumably time. The sequence number, OTU richness, Shannon diversity, ACE index and Chao1 index of soil fungal communities were higher under co-invasion of E. annuus and S. canadensis than under independent invasion of either individual species. The co-invasion of the two invasive species had a positive synergistic effect on diversity and abundance of soil fungal communities, partly to build a soil microenvironment to enhance competitiveness of the invaders. The changed diversity and community under co-invasion could modify resource availability and niche differentiation within the soil fungal communities, mediated by differences in leaf litter quality and quantity, which can support different fungal/microbial species in the soil. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  10. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling

    OpenAIRE

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N ...

  11. Additive genetic and maternal effects on litter traits in rabbits*.

    Science.gov (United States)

    Krogmeier, D; Dzapo, V; Mao, I L

    1994-01-12

    Additive genetic and maternal effects were estimated for several litter traits in rabbits. A total of 457 litters of 3267 animals from a reciprocal crossbreeding experiment were analysed by an animal model using a derivate-free REML procedure. Heritability estimates for litter size at birth, weaning and slaughter ranged from 0.09 to 0.25, for litter-weight traits from 0.00 to 0.13 and for preweaning and postweaning mortality rates from 0.00 to 0.19. Additive genetic contribution to the variation in a litter trait was found to be higher at birth and during the postweaning period than during the suckling period. Maternal effects accounted for approximately 10 % of the variation in most of the preweaning litter traits. Live litter size at birth was found to be the main source of variation in preweaning traits, explaining between 2.3 % and 43.2 % of the total variation. Heritability estimates and genetic correlations indicated live litter size at birth to be a useful selection criterion for the improvement of litter traits in rabbits. Our results indicated that a litter size of approximately 11 would be optimal before litter size at weaning and litter weight at weaning began to decline. Genetic selection for live litter size at birth would result in significant improvement in litter size and litter weight at later ages. ZUSAMMENFASSUNG: Schätzung additiv-genetischer und maternaler Effekte auf Wurfmerkmale beim Kaninchen An insgesamt 457 Würfen mit 3267 Einzeltieren, die aus einem reziproken Kreuzungsversuch stammten, wurden additiv-genetische und maternale Effekte für zahlreiche Wurfmerkmale anhand eines Tiermodells (DFREML-Methode) geschätzt. Heritabilitätsschätzungen wurden für Wurfgröße und Wurfgewicht zu unterschiedlichen Zeitpunkten (Geburt, Absetzen und Erreichen des Schlachtgewichts) aurchgeführt. Der additiv-genetische Variationsanteil an der Gesamtvariation war dabei bei der Geburt und nach dem Absetzen höher als während der Säugezeit. Die Sch

  12. Characterization of microplastic litter from oceans by an innovative approach based on hyperspectral imaging.

    Science.gov (United States)

    Serranti, Silvia; Palmieri, Roberta; Bonifazi, Giuseppe; Cózar, Andrés

    2018-03-05

    An innovative approach, based on HyperSpectral Imaging (HSI), was developed in order to set up an efficient method to analyze marine microplastic litter. HSI was applied to samples collected by surface-trawling plankton nets from several parts of the world (i.e. Arctic, Mediterranean, South Atlantic and North Pacific). Reliable information on abundance, size, shape and polymer type for the whole ensemble of plastic particles in each sample was retrieved from single hyperspectral images. The simultaneous characterization of the polymeric composition of the plastic debris represents an important analytical advantage considering that this information, and even the validation of the plastic nature of the small debris, is a common flaw in the analysis of marine microplastic pollution. HSI was revealed as a rapid, non-invasive, non-destructive and reliable technology for the characterization of the microplastic waste, opening a promising way for improving the plastic pollution monitoring. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Energetic Materials Effects on Essential Soil Processes: Decomposition of Orchard Grass (Dactylis glomerata) Litter in Soil Contaminated with Energetic Materials

    Science.gov (United States)

    2014-02-01

    oribatid mites and collembola were the second most abundant individual groups among microarthropods (prostigmatid mites were most abundant), and...jointly comprised approximately 40% of the microarthropod community throughout the study. Grazing activity of the oribatid mites and collembola provide...incorporating ecological principles into ERA methodologies. 21 LITERATURE CITED ASTM International. Standard Specification for Reagent Water; ASTM

  14. Litter mercury deposition in the Amazonian rainforest.

    Science.gov (United States)

    Fostier, Anne Hélène; Melendez-Perez, José Javier; Richter, Larissa

    2015-11-01

    The objective of this work was to assess the flux of atmospheric mercury transferred to the soil of the Amazonian rainforest by litterfall. Calculations were based on a large survey of published and unpublished data on litterfall and Hg concentrations in litterfall samples from the Amazonian region. Litterfall based on 65 sites located in the Amazon rainforest averaged 8.15 ± 2.25 Mg ha(-1) y(-1). Average Hg concentrations were calculated from nine datasets for fresh tree leaves and ten datasets for litter, and a median concentration of 60.5 ng Hg g(-1) was considered for Hg deposition in litterfall, which averaged 49 ± 14 μg m(-2) yr(-1). This value was used to estimate that in the Amazonian rainforest, litterfall would be responsible for the annual removing of 268 ± 77 Mg of Hg, approximately 8% of the total atmospheric Hg deposition to land. The impact of the Amazon deforestation on the Hg biogeochemical cycle is also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Poultry litter and the environment: Physiochemical properties of litter and soil during successive flock rotations and after remote site deposition.

    Science.gov (United States)

    Crippen, Tawni L; Sheffield, Cynthia L; Byrd, J Allen; Esquivel, Jesus F; Beier, Ross C; Yeater, Kathleen

    2016-05-15

    The U.S. broiler meat market has grown over the past 16 years and destinations for U.S. broiler meat exports expanded to over 150 countries. This market opportunity has spurred a corresponding increase in industrialized poultry production, which due to the confined space in which high numbers of animals are housed, risks accumulating nutrients and pollutants. The purpose of this research was to determine the level of pollutants within poultry litter and the underlying soil within a production facility; and to explore the impact of spent litter deposition into the environment. The study follows a production facility for the first 2.5 years of production. It monitors the effects of successive flocks and management practices on 15 physiochemical parameters: Ca, Cu, electrical conductivity, Fe, K, Mg, Mn, moisture, Na, NO3(-)/N, organic matter, P, pH, S, and Zn. Litter samples were collected in-house, after clean-outs and during stockpiling. The soil before house placement, after the clean-outs and following litter stockpiling was monitored. Management practices markedly altered the physiochemical profiles of the litter in-house. A canonical discriminant analysis was used to describe the relationship between the parameters and sampling times. The litter profiles grouped into five clusters corresponding to time and management practices. The soil in-house exhibited mean increases in all physiochemical parameters (2-297 fold) except Fe, Mg, %M, and pH. The spent litter was followed after deposition onto a field for use as fertilizer. After 20 weeks, the soil beneath the litter exhibited increases in EC, Cu, K, Na, NO3(-)/N, %OM, P, S and Zn; while %M decreased. Understanding the impacts of industrialized poultry farms on the environment is vital as the cumulative ecological impact of this land usage could be substantial if not properly managed to reduce the risk of potential pollutant infiltration into the environment. Published by Elsevier B.V.

  16. Litter stoichiometric traits of plant species of high-latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition.

    NARCIS (Netherlands)

    Aerts, R.; van Bodegom, P.M.; Cornelissen, J.H.C.

    2012-01-01

    High-latitude ecosystems are important carbon accumulators, mainly as a result of low decomposition rates of litter and soil organic matter. We investigated whether global change impacts on litter decomposition rates are constrained by litter stoichiometry. • Thereto, we investigated the

  17. Impacts of elevated atmospheric CO2 on litter quality, litter decomposability and nitrogen turnover rate of two oak species in a Mediterranean forest ecosystem

    NARCIS (Netherlands)

    Fayez Raiesi Gahrooee,

    1998-01-01

    Elevated CO2 may affect litter quality of plants, and subsequently C and N cycling in terrestrial ecosystems, but changes in litter quality associated with elevated CO2 are poorly known. Abscised leaf litter of two oak species (Quercus cerris L., and Q. pubescens Willd.) exposed to long-term

  18. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    Directory of Open Access Journals (Sweden)

    Bing Mao

    Full Text Available Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  19. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    Science.gov (United States)

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  20. Genetic parameters for canalisation analysis of litter size and litter weight traits at birth in mice

    Directory of Open Access Journals (Sweden)

    Salgado Concepción

    2006-09-01

    Full Text Available Abstract The aim of this research was to explore the genetic parameters associated with environmental variability for litter size (LS, litter weight (LW and mean individual birth weight (IW in mice before canalisation. The analyses were conducted on an experimental mice population designed to reduce environmental variability for LS. The analysed database included 1976 records for LW and IW and 4129 records for LS. The total number of individuals included in the analysed pedigree was 3997. Heritabilities estimated for the traits under an initial exploratory approach varied from 0.099 to 0.101 for LS, from 0.112 to 0.148 for LW and from 0.028 to 0.033 for IW. The means of the posterior distribution of the heritability under a Bayesian approach were the following: 0.10 (LS, 0.13 (LW and 0.03 (IW. In general, the heritabilities estimated under the initial exploratory approach for the environmental variability of the analysed traits were low. Genetic correlations estimated between the trait and its variability reached values of -0.929 (LS, -0.815 (LW and 0.969 (IW. The results presented here for the first time in mice may suggest a genetic basis for variability of the evaluated traits, thus opening the possibility to be implemented in selection schemes.

  1. Abundance and diaspore weight in rare and common prairie grasses.

    Science.gov (United States)

    Rabinowitz, Deborah

    1978-01-01

    Abundance (g/m 2 ) and diaspore weight are positively correlated in seven species of perennial grasses that occur in prairies. The rare grasses (10.0 g/m 2 ) have heavy dispersal units (2.23 to 2.80 mg). This result is the first reported differentiating trait between related rare and common organisms occurring in same habitat.Three hypotheses that explain this phenomenon are compared; the third most likely holds. First, rare grasses may be rare because their small seeds are less successful in establishment than those of common grasses. Second, if the persistence of small populations is marginal, rare grasses may devote less energy (or other currency) to seed production. Third, rare grasses may be colonizers of spatially and temporally rare microsites appropriate for growth and thus have seeds adapted for longer distance dispersal than those of common grasses. This last hypothesis suggests a new pathway for the evolution of weeds.

  2. Effect of postnatal litter size on adult aggression in the laboratory mouse.

    Science.gov (United States)

    Ryan, V; Wehmer, F

    1975-07-01

    Growth, emotionality, food competition, and aggression were examined in mice nursed in litters of 3 or 9 and reared in isolation until testing. Animals from large litters were lighter at weaning and in adulthood and were more emotional in the open field than subjects from small litters. They did not win more food competition tests than subjects from small litters although their consummatory behavior during food competition tests was greater. Subjects from large litters were more aggressive in initial encounters, but over repeated encounters became more submissive. In a 2nd open-field test, emotionality of large-litter subjects was reduced more than that of subjects from small litters. When later placed in group-living cages, subjects from small litters sustained less long term physical assault than subjects from large litters. High correlations were found between the 4 measures of brief aggression.

  3. Nowcasting daily minimum air and grass temperature

    Science.gov (United States)

    Savage, M. J.

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  4. Methane, nitrous oxide and ammonia emissions from pigs housed on litter and from stockpiling of spent litter

    KAUST Repository

    Phillips, F. A.

    2016-05-05

    Mitigation of agricultural greenhouse gas emissions is a target area for the Australian Government and the pork industry. The present study measured methane (CH4), nitrous oxide (N2O) and ammonia (NH3) from a deep-litter piggery and litter stockpile over two trials in southern New South Wales, to compare emissions from housing pigs on deep litter with those of pigs from conventional housing with uncovered anaerobic effluent-treatment ponds. Emissions were measured using open-path Fourier transform infrared spectrometry, in conjunction with a backward Lagrangian stochastic model. Manure excretion was determined by mass balance and emission factors (EFs) were developed to report emissions relative to volatile solids and nitrogen (N) input. Nitrous oxide emissions per animal unit (1 AU ≤ 500 kg liveweight) from deep-litter sheds were negligible in winter, and 8.4 g/AU.day in summer. Ammonia emissions were 39.1 in winter and 52.2 g/AU.day in summer, while CH4 emissions were 16.1 and 21.6 g/AU.day in winter and summer respectively. Emission factors averaged from summer and winter emissions showed a CH4 conversion factor of 3.6%, an NH3-N EF of 10% and a N2O-N EF of 0.01 kg N2O-N/kg N excreted. For the litter stockpile, the simple average of summer and winter showed an EF for NH3-N of 14%, and a N2O-N EF of 0.02 kg N2O-N/kg-N of spent litter added to the stockpile. We observed a 66% and 80% decrease in emissions from the manure excreted in litter-based housing with litter stockpiling or without litter stockpiling, compared with conventional housing with an uncovered anaerobic effluent-treatment pond. This provides a sound basis for mitigation strategies that utilise litter-based housing as an alternative to conventional housing with uncovered anaerobic effluent-treatment ponds. © CSIRO 2016.

  5. Species-specific effects of woody litter on seedling emergence and growth of herbaceous plants.

    Directory of Open Access Journals (Sweden)

    Kadri Koorem

    Full Text Available The effect of litter on seedling establishment can influence species richness in plant communities. The effect of litter depends on amount, and also on litter type, but relatively little is known about the species-specific effects of litter. We conducted a factorial greenhouse experiment to examine the effect of litter type, using two woody species that commonly co-occur in boreonemoral forest--evergreen spruce (Picea abies, deciduous hazel (Corylus avellana, and a mixture of the two species--and litter amount--shallow (4 mm, deep (12 mm and leachate--on seedling emergence and biomass of three understorey species. The effect of litter amount on seedling emergence was highly dependent on litter type; while spruce needle litter had a significant negative effect that increased with depth, seedling emergence in the presence of hazel broadleaf litter did not differ from control pots containing no litter. Mixed litter of both species also had a negative effect on seedling emergence that was intermediate compared to the single-species treatments. Spruce litter had a marginally positive (shallow or neutral effect (deep on seedling biomass, while hazel and mixed litter treatments had significant positive effects on biomass that increased with depth. We found non-additive effects of litter mixtures on seedling biomass indicating that high quality hazel litter can reduce the negative effects of spruce. Hazel litter does not inhibit seedling emergence; it increases seedling growth, and creates better conditions for seedling growth in mixtures by reducing the suppressive effect of spruce litter, having a positive effect on understorey species richness.

  6. Solid state fermentation of broiler litter for production of biocontrol agents.

    Science.gov (United States)

    Adams, T T; Eiteman, M A; Hanel, B M

    2002-03-01

    Several varieties of heat-sterilized broiler litter with 60% (wet basis, wb) moisture content were substrate in solid-state fermentations to produce biocontrol agents. Litter varieties included litter produced by one flock of broilers from medicated and non-medicated controlled rations, and litter produced by two flocks and four flocks on a single application of bedding material from medicated commercial sources. Litter preparations were inoculated with monocultures of Bacillus thuringiensis serovar japonensis strain Buibui, a pathogen of Japanese beetle larvae (Popillia japonica), or Pseudomonas fluorescens 2-79. B. thuringiensis did not grow in unextracted 1-flock litter nor in water extracted litter, but grew in methanol extracted litter to 5 x 10(10) cell forming units (CFU)/g litter (dry weight, dw) and a spore count of 1 x 10(10) CFU/g litter (dw). B. thuringiensis also grew in unprocessed 2-flock and 4-flock litter, achieving cell counts of 3 x 10(9) and 1 x 10(9) CFU/g litter (dw), respectively, and spore counts of 1 x 10(9) CFU/g litter (dw). P. fluorescens grew in medicated 1-flock litter with no extraction to a cell density greater than 4 x 10(11) CFU/g litter (dw). Bioassays in soil containing over 0.5% (db) litter fermented with B. thuringiensis resulted in over 90% mortality in 21 days for first instars of Japanese beetle when compared to a control treatment using compost without fermented litter. The investigations demonstrate that bacterial biocontrol agents produced via solid substrate fermentations using broiler poultry litter have potential in biocontrol applications in the soil environment.

  7. ANATOMIC STRUCTURE OF CAMPANULA ROTUNDIFOLIA L. GRASS

    OpenAIRE

    V. N. Bubenchikova; E. A. Nikitin

    2017-01-01

    The article present results of the study for a anatomic structure of Campanula rotundifolia grass from Campanulaceae family. Despite its dispersion and application in folk medicine, there are no data about its anatomic structure, therefore to estimate the indices of authenticity and quality of raw materials it is necessary to develop microdiagnostical features in the first place, which could help introducing of thisplant in a medical practice. The purpose of this work is to study anatomical s...

  8. Above and belowground controls on litter decomposition in semiarid ecosystems: effects of solar radiation, water availability and litter quality

    Science.gov (United States)

    Austin, A. T.; Araujo, P. I.; Leva, P. E.; Ballare, C. L.

    2008-12-01

    The integrated controls on soil organic matter formation in arid and semiarid ecosystems are not well understood and appear to stem from a number of interacting controls affecting above- and belowground carbon turnover. While solar radiation has recently been shown to have an important direct effect on carbon loss in semiarid ecosystems as a result of photochemical mineralization of aboveground plant material, the mechanistic basis for photodegradative losses is poorly understood. In addition, there are large potential differences in major controls on above- and belowground decomposition in low rainfall ecosystems. We report on a mesocosm and field study designed to examine the relative importance of different wavelengths of solar radiation, water availability, position of senescent material above- and belowground and the importance of carbon litter quality in determining rates of abiotic and biotic decomposition. In a factorial experiment of mesocosms, we incubated leaf and root litter simultaneously above- and belowground and manipulated water availability with large and small pulses. Significant interactions between position-litter type and position-pulse sizes demonstrated interactive controls on organic mass loss. Aboveground decomposition showed no response to pulse size or litter type, as roots and leaves decomposed equally rapidly under all circumstances. In contrast, belowground decomposition was significantly altered by litter type and water pulses, with roots decomposing significantly slower and small water pulses reducing belowground decomposition. In the field site, using plastic filters which attenuated different wavelengths of natural solar radiation, we found a highly significant effect of radiation exclusion on mass loss and demonstrated that both UV-A and short-wave visible light can have important impacts on photodegradative carbon losses. The combination of position and litter quality effects on litter decomposition appear to be critical for the

  9. Performance and nutrient intake of Zebu Heifers fed guinea grass ...

    African Journals Online (AJOL)

    Sixteen zebu heifors were ted 0. 20. 40 and 60% autoclaved broiler litter in total mixed rations. The effect of treatment was evaluated on feed intake. mean growth rate. digestibility coetlicient and digestible nutrient intake. Autoclaved broiler litter appeared to be well accepted by heiters even when included in ration at 60% of ...

  10. Peanut cake concentrations in massai grass silage

    Directory of Open Access Journals (Sweden)

    Luciano S. Lima

    2013-03-01

    Full Text Available Objective. This experiment was conducted to evaluate the best concentration of peanut cake in the ensiling of massai grass of the chemical-bromatological composition, fermentative characteristics, forage value rate, ingestion estimates, and digestibility of dry matter in the silage. Materials and methods. The experiment was carried out at the Experimental Farm of São Gonçalo dos Campos at the Federal University of Bahia, Brazil. The treatments consisted of massai grass that was cut at 40 days and dehydrated, in addition to 0%, 8%, 16%, and 24% peanut cake in the fresh matter and treatment without cake. The material was compressed in experimental silos (7 liter that were opened after 76 days. Results. The addition of 8-24% peanut cake improved the silage’s chemical-bromatological parameters, increased the dry matter and non-fiber carbohydrates and reduced the fibrous components. There was a linear increase in the estimated values of digestibility and the ingestion of dry matter depending on the levels of peanut cake in the silage. There was an improvement in the fermentative characteristics, with a quadratic effect positive for levels of ammoniacal nitrogen. The forage value rate increased linearly with the inclusion of peanut cake. Conclusions. The inclusion of up to 24% peanut cake during ensiling of massai grass increases the nutritive value of silage and improves fermentation characteristics.

  11. Litter survey detects the South Atlantic 'garbage patch'.

    Science.gov (United States)

    Ryan, Peter G

    2014-02-15

    A distance-based technique was used to assess the distribution and abundance of floating marine debris (>1cm) in the southeast Atlantic Ocean between Cape Town and Tristan da Cunha, crossing the southern edge of the South Atlantic 'garbage patch' predicted by surface drift models. Most litter was made of plastic (97%). Detection distances were influenced by the size and buoyancy of litter items. Litter density decreased from coastal waters off Cape Town (>100 items km(-2)) to oceanic waters (<10 items km(-2)), and was consistently higher (6.2 ± 1.3 items km(-2)) from 3 to 8°E than in adjacent oceanic waters (2.7 ± 0.3 items km(-2)) or in the central South Atlantic around Tristan (1.0 ± 0.4 items km(-2)). The area with high litter density had few seaweeds, suggesting that most litter had been drifting for a long time. The results indicate that floating debris is accumulating in the South Atlantic gyre as far south as 34-35°S. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Combustion of poultry litter in a fluidised bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    P. Abelha; I. Gulyurtlu; D. Boavida; J. Seabra Barros; I. Cabrita; J. Leahy; B. Kelleher; M. Leahy [DEECA-INETI, Lisbon (Portugal)

    2003-04-01

    Combustion studies of poultry litter alone or mixed with peat by 50% on weight basis were undertaken in an atmospheric bubbling fluidised bed. Because of high moisture content of poultry litter, there was some uncertainty whether the combustion could be sustained on 100% poultry litter and as peat is very available in Ireland, its presence was considered to help to improve the combustion. However, the results showed that, as long as the moisture content of poultry litter was kept below 25%, the combustion did not need the addition of peat. The main parameters that were investigated are (i) moisture content, (ii) air staging, and (iii) variations in excess air levels along the freeboard. The main conclusions of the results are (i) combustion was influenced very much by the conditions of the fuel supply, (ii) the steady fuel supply was strongly dependent on the moisture content of the poultry litter, (iii) temperature appeared to be still very influential in reducing the levels of unburned carbon and hydrocarbons released from residues, (iv) the air staging in the freeboard improved combustion efficiency by enhancing the combustion of volatiles released from residues in the riser and (vi) NOx emissions were influenced by air staging in the freeboard. Particles collected from the bed and the two cyclones were analysed to determine the levels of heavy metals and the leachability tests were carried out with ashes collected to verify whether or not they could safely be used in agricultural lands. 8 refs., 1 fig., 8 tabs.

  13. SOA formation potential of emissions from soil and leaf litter.

    Science.gov (United States)

    Faiola, Celia L; Vanderschelden, Graham S; Wen, Miao; Elloy, Farah C; Cobos, Douglas R; Watts, Richard J; Jobson, B Thomas; Vanreken, Timothy M

    2014-01-21

    Soil and leaf litter are significant global sources of small oxidized volatile organic compounds, VOCs (e.g., methanol and acetaldehyde). They may also be significant sources of larger VOCs that could act as precursors to secondary organic aerosol (SOA) formation. To investigate this, soil and leaf litter samples were collected from the University of Idaho Experimental Forest and transported to the laboratory. There, the VOC emissions were characterized and used to drive SOA formation via dark, ozone-initiated reactions. Monoterpenes dominated the emission profile with emission rates as high as 228 μg-C m(-2) h(-1). The composition of the SOA produced was similar to biogenic SOA formed from oxidation of ponderosa pine emissions and α-pinene. Measured soil and litter monoterpene emission rates were compared with modeled canopy emissions. Results suggest surface soil and litter monoterpene emissions could range from 12 to 136% of canopy emissions in spring and fall. Thus, emissions from leaf litter may potentially extend the biogenic emissions season, contributing to significant organic aerosol formation in the spring and fall when reduced solar radiation and temperatures reduce emissions from living vegetation.

  14. Litter Fall and Energy Flux in a Mangrove Ecosystem

    Science.gov (United States)

    Wafar, S.; Untawale, A. G.; Wafar, M.

    1997-01-01

    Production, elemental composition and in situdecomposition of litter of Rhizophora apiculata, R. mucronata, Sonneratia albaand Avicenna officinaliswere studied in a mangrove ecosystem fringing Madovi-Zuari Estuaries on the Central West Coast of India. Litter yield ranged from 10.2 tonnes ha -1year -1in A. officinalisthrough 11.8 ( R. apiculataand R. mucronata) to 17 tonnes ha -1year -1in S. alba. Seasonally maximum litter fall was in pre- and post-monsoon monthe, with the lowest production in the monsoon. Modelling of litter fall as a function of Julian day and six environmental parameters showed that the observed changes can be explained in terms of dry/wet season and wind speed, with a 1000. Total decomposition (98-100% loss in dry weight and C, and >90% loss in N and P) of yellow leaves was within 15 weeks in the two Rhizosporaspp. and S. alba, and within 8 weeks in A. officinalis. In all four species, mass changes during decomposition obeyed first-order kinetics. Comparison of C, N and P fluxes from the decomposing mangrove litter with phytoplankton, bacterial and secondary production in the estuarine waters showed that mangrove production is important mainly for the C budget of the Estuaries and in sustaining the microbial food chain and nutrient regeneration, rather than the particulate food chain directly.

  15. Nitrogen Transformations in Broiler Litter-Amended Soils

    Directory of Open Access Journals (Sweden)

    Kokoasse Kpomblekou-A

    2012-01-01

    Full Text Available Nitrogen mineralization rates in ten surface soils amended with (200 μg N g−1 soil or without broiler litter were investigated. The soil-broiler litter mixture was incubated at 25±1∘C for 28 weeks. A nonlinear regression approach for N mineralization was used to estimate the readily mineralizable organic N pools (N0 and the first-order rate constant (k. The cumulative N mineralized in the nonamended soils did not exceed 80 mg N kg−1 soil. However, in Decatur soil amended with broiler litter 2, it exceeded 320 mg N kg−1 soil. The greatest calculated N0 of the native soils was observed in Sucarnoochee soil alone (123 mg NO3− kg−1 soil which when amended with broiler litter 1 reached 596 mg N kg−1 soil. The added broiler litter mineralized initially at a fast rate (k1 followed by a slow rate (k2 of the most resistant fraction. Half-life of organic N remaining in the soils alone varied from 33 to 75 weeks and from 43 to 15 weeks in the amended soils. When N0 was regressed against soil organic N (=0.782∗∗ and C (=0.884∗∗∗, positive linear relationships were obtained. The N0 pools increased with sand but decreased with silt and clay contents.

  16. Determination of the acute toxicity of isoniazid to three invasive carp species and rainbow trout in static exposures

    Science.gov (United States)

    Schreier, Theresa M.; Hubert, Terrance D.

    2015-01-01

    Three invasive fishes of considerable concern to aquatic resource managers are the Hypophthalmichthys nobilis (bighead carp),Hypophthalmichthys molitrix (silver carp), and Ctenopharyngodon idella (grass carp), collectively known as Asian carps. There is a need for an effective chemical control agent for Asian carps. Isoniazid was identified as a potential toxicant for grass carp. The selective toxicity of isoniazid to grass carp was verified as a response to an anecdotal report received in 2013. In addition, the toxicity of isoniazid to bighead carp, silver carp, and Oncorhynchus mykiss (rainbow trout) was evaluated. Isoniazid was not toxic to grass carp at the reported anecdotal concentration, which was 13 milligrams per liter. Isoniazid (130 milligrams per liter) was not selectively toxic to bighead carp, silver carp, or grass carp when compared to rainbow trout.

  17. DECOTAB: a multipurpose standard substrate to assess effects of litter quality on microbial decomposition and invertebrate consumption

    NARCIS (Netherlands)

    Kampfraath, A.A.; Hunting, E.R.; Mulder, C.; Breure, A.M.; Gessner, M.O.; Kraak, M.H.S.; Admiraal, W.

    2012-01-01

    Currently available tools for studying plant litter decomposition and invertebrate consumption in aquatic ecosystems have at least 2 major limitations: 1) the difficulty of manipulating litter chemical composition to provide mechanistic insights into attributes of litter quality controlling

  18. Biodiversity at the plant-soil interface: microbial abundance and community structure respond to litter mixing.

    Science.gov (United States)

    Chapman, Samantha K; Newman, Gregory S

    2010-03-01

    The interactive effects of diversity in plants and microbial communities at the litter interface are not well understood. Mixtures of plant litter from different species often decompose differently than when individual species decompose alone. Previously, we found that litter mixtures of multiple conifers decomposed more rapidly than expected, but litter mixtures that included conifer and aspen litter did not. Understanding the mechanisms underlying these diversity effects may help explain existing anomalous decay dynamics and provide a glimpse into the elusive linkage between plant diversity and the fungi and bacteria that carry out decomposition. We examined the microbial communities on litter from individual plant species decomposing both in mixture and alone. We assessed two main hypotheses to explain how the decomposer community could stimulate mixed-litter decomposition above predicted rates: either by being more abundant, or having a different or more diverse community structure than when microbes decompose a single species of litter. Fungal, bacterial and total phospholipid fatty acid microbial biomass increased by over 40% on both conifer and aspen litter types in mixture, and microbial community composition changed significantly when plant litter types were mixed. Microbial diversity also increased with increasing plant litter diversity. While our data provide support for both the increased abundance hypothesis and the altered microbial community hypothesis, microbial changes do not translate to predictably altered litter decomposition and may only produce synergisms when mixed litters are functionally similar.

  19. Metal and nutrient dynamics in decomposing tree litter on a metal contaminated site

    International Nuclear Information System (INIS)

    Van Nevel, Lotte; Mertens, Jan; Demey, Andreas; De Schrijver, An; De Neve, Stefaan; Tack, Filip M.G.; Verheyen, Kris

    2014-01-01

    In a forest on sandy, metal polluted soil, we examined effects of six tree species on litter decomposition rates and accompanied changes in metal (Cd, Zn) and nutrient (base cations, N, C) amounts. Decomposition dynamics were studied by means of a litterbag experiment lasting for 30 months. The decomposition peak occurred within the first year for all tree species, except for aspen. During litter decomposition, high metal litter types released part of their accumulated metals, whereas low metal litter types were characterized by a metal enrichment. Base cations, N and C were released from all litter types. Metal release from contaminated litter might involve risks for metal dispersion towards the soil. On the other hand, metal enrichment of uncontaminated litter may be ecologically relevant as it can be easily transported or serve as food source. - Highlights: • Litter decomposition peak occurred within the first year for all tree species, except for aspen. • Base cations, N and C were released from all litter types during decomposition. • Cd and Zn were released from the high metal litter types. • Low metal litter types were characterized by a net Cd and Zn enrichment. • Metal and nutrient releases were reflected in topsoil characteristics. - Litter decomposition rates, as well as enrichment and release dynamics of metals and nutrients in decomposing litter were divergent under the different tree species

  20. Decoupling of lignin and total litter decomposition across North American forest soils: a phenomenon to reconcile old and new paradigms of soil organic matter?

    Science.gov (United States)

    Hall, S. J.; Hammel, K.

    2017-12-01

    An "old" paradigm of soil organic matter (SOM) posited that biochemically "recalcitrant" lignin derivatives were a dominant constituent. Over the past decade(s), evidence for a newer paradigm has emerged which suggests that recalcitrance has little long-term impact on the biochemical composition of SOM, and that lignin is relatively unimportant in comparison with dead microbial biomass. Yet, methodological biases have hampered accurate quantification of lignin dynamics in mineral soils, and may have led to systematic underestimates of lignin stocks and turnover. Here, we sought to test this aspect of the "new" SOM paradigm. Synthetic position-specific 13C-labeled lignins provide a robust quantitative method to track the mineralization and fate of lignin moieties in mineral soils. Relatively few microbial taxa are known to depolymerize macromolecular lignin, and lignin derivatives can specifically associate with iron oxide mineral phases. Consequently, we hypothesized that decomposition of lignin is poorly correlated with total litter decomposition across ecosystems, and that lignin may represent a variable but significant component of decadal-cycling SOM. We incubated 10 forest soils spanning diverse North American ecosystems over seven months under laboratory conditions at constant temperature and moisture. Soils were incubated alone, with added C4 grass litter and natural isotope abundance lignin, and with added C4 litter and 13Cß-labeled lignin. These treatments allowed us to partition respiration for each soil from SOM, litter, and the Cß moiety of lignin—which is diagnostic for cleavage of the polymer. Consistent with our hypothesis, we found much greater variability (ten-fold) in cumulative lignin mineralization relative to bulk litter (two-fold) among soils. Multiple-pool first-order decay models implied that mean turnover times for lignin ranged from one to several decades among soils, relative to several years for bulk litter. Our results suggest a

  1. Heavy metal concentrations in forest litter - indicators of pollutant depositions

    International Nuclear Information System (INIS)

    Angehrn-Bettinazzi, C.; Hertz, J.

    1990-01-01

    By means of a comparison of the heavy metal concentrations in organic litter from different sites it was examined to what extent the heavy metal concentrations correlate with the atmospheric pollution situation. It follows from the variance analyses: The atmospheric pollution situation is the dominating factor for the heavy metal concentration in L litter. The elements Cd and Zn show a pH-sensitivity at the same time. The lead concentration in the L n and L v horizons reflects the atmospheric pollution situation of the corresponding site. Specific pollution patterns, e.g. in the case of hillside sites, are neither detected through the gravitational deposition (open land) nor through the airborne dust concentration; these can be recognized by the monitor 'litter'. Only horizons in the intercrown area with identical tree vegetation, which are characterized in detail, must be used for monitoring. (orig.) [de

  2. Treatment of grass pollen allergy: focus on a standardized grass allergen extract - Grazax®.

    Science.gov (United States)

    Calderón, Moisés; Brandt, Tove

    2008-12-01

    Immunotherapy is the only treatment for allergy that has the potential to alter the natural course of the disease. Sublingual immunotherapy (SLIT) for grass pollen-induced rhino-conjunctivitis has been developed to make immunotherapy available to a broader group of allergic patients. In the largest clinical programme ever conducted with allergen-specific immunotherapy, over 1,700 adults and 260 children have been exposed to Grazax(®). Grazax is formulated as an oral lyophilisate (tablet) for sublingual administration, containing 75,000 SQ-T standardized allergen extract of grass pollen from Phleum pratense. Grazax is indicated for treatment of grass pollen-induced rhinitis and conjunctivitis in adult patients with clinically relevant symptoms and diagnosed with a positive skin prick test and/or specific IgE test to grass pollen. In phase I trials doses from 2,500 to 1,000,000 SQ-T were tested. All doses were well tolerated and 75,000 SQ-T, with approximately 15 mug major allergen protein, was chosen as the optimal dose. Three phase III trials are ongoing, one being a long-term trial. Results from GT-08 trial first and second treatment years showed a reduction of 30% and 36%, respectively, in daily rhino-conjunctivitis symptom scores and a reduction of 38% and 46% of daily rhino-conjunctivitis medication scores compared with placebo over the entire grass pollen season. Subjects treated with Grazax also had an increased number of well days and improved quality of life, and more subjects experienced excellent rhino-conjunctivitis control. The most common adverse events related to Grazax are local reactions, such as pruritus, edema mouth, ear pruritus, throat irritation, and sneezing. We conclude that Grazax is efficacious and safe for treatment of rhino-conjunctivitis due to grass pollen allergy.

  3. Measurement and characterization of cellulase activity in sclerophyllous forest litter.

    Science.gov (United States)

    Criquet, Stéven

    2002-07-01

    Cellulases are enzymatic proteins which hydrolyze cellulose polymers to smaller oligosaccharides, cellobiose and glucose. They consist in three major types of enzymes: endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91) and beta-glucosidases (EC 3.2.1.21) which play an essential role in carbon turnover of forest ecosystem. The aim of this study was firstly to determine the parameters (i.e. buffer type, pH, temperature, quantity of litter, incubation time and reagent type) which affect the measurement of cellulase activity in a sclerophyllous forest litter, and secondly to compare two methods for measuring cellulase activity: a direct method and an extraction method. In the direct method, the litter was directly incubated with a buffered solution containing the enzyme substrate, whereas in the extraction method, the cellulases were firstly extracted before measuring their activity. The results were compared with other studies about soil cellulase activity, and it appeared that several parameters (buffer type, pH, temperature and sample quantity) which influence the measurement of cellulase activity differ according to whether a soil or a litter is considered. Concerning the procedure used for the measurement of cellulase activity, results showed that the activity values were higher when using an extraction procedure than when using a direct procedure. The extraction procedure, combined with a concentration stage of the extract, also allowed electrophoretic analysis (PAGE) of the cellulases extracted from the litter. The electrophoretic pattern revealed two cellulase isoenzymes which may be related to the occurrence of two pH-activity peaks of these enzymes when citrate buffer was used for the measurement of cellulase activity in the litter.

  4. Litter burial and exhumation: spatial and temporal distribution on a cobble pocket beach.

    Science.gov (United States)

    Williams, A T; Tudor, D T

    2001-11-01

    A cobble beach (-6 diameter to -8 diameter) located on the South Wales coastline, UK, was studied over a three-month winter period to assess litter input levels. After total beach litter clearance, six surveys were conducted at consecutive spring tides which involved marking of previously unrecorded litter. The beach was soon inundated with debris, predominantly plastic beverage containers. Some marked litter was found to disappear from the beach surface, re-emerging weeks later which suggests that the potential for litter burial has been underestimated in litter research. Higher wave energies between surveys coincided with higher levels of previously unseen litter. These new inputs consisted of sea borne and exhumed litter. Items larger than the surrounding cobbles were found to work their way back to the surface of the beach after burial, smaller items remained buried. Pits dug into the cobble ridge confirmed the burial of mainly small items.

  5. Microhabitat effects of litter temperature and moisture on forest-floor invertebrate communities

    Science.gov (United States)

    Tim A. Christiansen; Sue A. Perry; William B. Perry

    1996-01-01

    Litter temperature and moisture may be altered due to changes in global climate. We investigated the effect of small changes in litter temperature and moisture on forest-floor communities in West Virginia.

  6. LBA-ECO ND-11 Litter Decomposition, Carbon, and Nitrogen Dynamics in Agroforestry

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains the results of an experiment to determine litter decomposition and dynamics of carbon and nitrogen release from plant litter of differing...

  7. LBA-ECO ND-11 Litter Decomposition, Carbon, and Nitrogen Dynamics in Agroforestry

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains the results of an experiment to determine litter decomposition and dynamics of carbon and nitrogen release from plant litter of...

  8. The importance of cross-reactivity in grass pollen allergy

    Directory of Open Access Journals (Sweden)

    Aleksić Ivana

    2014-01-01

    Full Text Available According to the data obtained from in vivo and in vitro testing in Serbia, a significant number of patients have allergic symptoms caused by grass pollen. We examined the protein composition of grass pollens (Dactylis glomerata, Lolium perenne and Phleum pratense and cross-reactivity in patients allergic to grass pollen from our region. The grass pollen allergen extract was characterized by SDS-PAGE, while cross-reactivity of single grass pollens was revealed by immunoblot analysis. A high degree of cross-reactivity was demonstrated for all three single pollens in the sera of allergic patients compared to the grass pollen extract mixture. Confirmation of the existence of cross-reactivity between different antigenic sources facilitates the use of monovalent vaccines, which are easier to standardize and at the same time prevent further sensitization of patients and reduces adverse reactions. [Projekat Ministarstva nauke Republike Srbije, br. 172049 i br. 172024

  9. Rye-grass as an energy crop using biogas technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-11-15

    The viability of using rye-grass in the UK as a wet energy crop was investigated in this project. The harvesting of rye-grass, the operation of pilot-scale digesters fed with cut rye-grass, and the operation of a biogas plant are described. Use of the digestate as a fertilizer for the grass was examined and the need for added farm manure or slurry to enrich the nutrient content of the grass and produce better yields is noted. Details are given of the digester design and the design of a commercial-scale biogas plant able to take a variety of liquid and solid feeds. Energy balance, the economics of the commercial design, the ensiling of the grass, and methane yields are considered.

  10. Litter size, fur quality and genetic analyses of American mink

    DEFF Research Database (Denmark)

    Thirstrup, Janne Pia

    Mink is a production animal breed for the fur. Both quality and quantity of the produced skin are important for the producer. In these analyses both fur quality traits, such as structure of guard hair and wool, which determines the quality of the skin, and litter size which determines the quantity...... of the skin, have been analyzed. Both fur quality traits and litter size are complex traits underlying quantitative genetic variation. Methods for estimating genetic variance, spanning from pedigree information to the use of different genetic markers, have been utilized in order to gain knowledge about...

  11. Det litterære rum i Don Quixote

    DEFF Research Database (Denmark)

    Brink, Dennis Meyhoff

    2003-01-01

    Don Quixote kommer til verden i det måske mest afgørende øjeblik i den vestlige rumopfattelses historie - nemlig i det øjeblik, hvor forestillingen om, at vi lever i et uendeligt univers, erstatter den gammeleuropæiske forestilling om verdensrummet som et endeligt kosmos. Det nye verdensrum danner...... for første gang baggrunden for konstruktionen af et litterært rum i Don Quixote, og er på denne måde med til at skabe en ny litterær form: Romanen....

  12. Potential for post-closure radionuclide redistribution due to biotic intrusion: aboveground biomass, litter production rates, and the distribution of root mass with depth at material disposal area G, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    French, Sean B [Los Alamos National Laboratory; Christensen, Candace [Los Alamos National Laboratory; Jennings, Terry L [Los Alamos National Laboratory; Jaros, Christopher L [Los Alamos National Laboratory; Wykoff, David S [Los Alamos National Laboratory; Crowell, Kelly J [Los Alamos National Laboratory; Shuman, Rob [URS

    2008-01-01

    Low-level radioactive waste (LLW) generated at the Los Alamos National Laboratories (LANL) is disposed of at LANL's Technical Area (T A) 54, Material Disposal Area (MDA) G. The ability of MDA G to safely contain radioactive waste during current and post-closure operations is evaluated as part of the facility's ongoing performance assessment (PA) and composite analysis (CA). Due to the potential for uptake and incorporation of radio nuclides into aboveground plant material, the PA and CA project that plant roots penetrating into buried waste may lead to releases of radionuclides into the accessible environment. The potential amount ofcontamination deposited on the ground surface due to plant intrusion into buried waste is a function of the quantity of litter generated by plants, as well as radionuclide concentrations within the litter. Radionuclide concentrations in plant litter is dependent on the distribution of root mass with depth and the efficiency with which radionuclides are extracted from contaminated soils by the plant's roots. In order to reduce uncertainties associated with the PA and CA for MDA G, surveys are being conducted to assess aboveground biomass, plant litter production rates, and root mass with depth for the four prominent vegetation types (grasses, forbs, shrubs and trees). The collection of aboveground biomass for grasses and forbs began in 2007. Additional sampling was conducted in October 2008 to measure root mass with depth and to collect additional aboveground biomass data for the types of grasses, forbs, shrubs, and trees that may become established at MDA G after the facility undergoes final closure, Biomass data will be used to estimate the future potential mass of contaminated plant litter fall, which could act as a latent conduit for radionuclide transport from the closed disposal area. Data collected are expected to reduce uncertainties associated with the PA and CA for MDA G and ultimately aid in the assessment and

  13. Determining the regional potential for a grass biomethane industry

    International Nuclear Information System (INIS)

    Smyth, Beatrice M.; Smyth, Henry; Murphy, Jerry D.

    2011-01-01

    Research highlights: → We identified assessment criteria for determining the regional potential for grass biomethane. → Grass biomethane is distributed via the natural gas grid. → The criteria include: land use; grass yields; gas grid coverage; availability of co-substrates. → The county with the highest potential can fuel 50% of cars or supply 130% of domestic gas consumption. - Abstract: Grass biogas/biomethane has been put forward as a renewable energy solution and it has been shown to perform well in terms of energy balance, greenhouse gas emissions and policy constraints. Biofuel and energy crop solutions are country-specific and grass biomethane has strong potential in countries with temperate climates and a high proportion of grassland, such as Ireland. For a grass biomethane industry to develop in a country, suitable regions (i.e. those with the highest potential) must be identified. In this paper, factors specifically related to the assessment of the potential of a grass biogas/biomethane industry are identified and analysed. The potential for grass biogas and grass biomethane is determined on a county-by-county basis using multi-criteria decision analysis. Values are assigned to each county and ratings and weightings applied to determine the overall county potential. The potential for grass biomethane with co-digestion of slaughter waste (belly grass) is also determined. The county with the highest potential (Limerick) is analysed in detail and is shown to have ready potential for production of gaseous biofuel to meet either 50% of the vehicle fleet or 130% of the domestic natural gas demand, through 25 facilities at a scale of ca. 30 kt yr -1 of feedstock. The assessment factors developed in this paper can be used in other resource studies into grass biomethane or other energy crops.

  14. Development of a Numerical Model for Evaluating the Effect of Litter Layer on Evaporation

    OpenAIRE

    Ho-Taek, Park; Shigeaki, Hattori; Takafumi, Tanaka; School of Bioagricultural Sciences, Nagoya University; School of Bioagricultural Sciences, Nagoya University; School of Bioagricultural Sciences, Nagoya University

    1998-01-01

    A numerical model (LITEM) to evaluate the effect of the litter layer on evaporation was developed and used to estimate evaporation, soil temperature and soil water content. This model includes a sub-model to estimate the resistance of the litter layer to evaporation with its thickness and volumetric water content. The resistance of the litter layer to evaporation increases as volumetric water content of the litter layer decreases and as its thickness increases. Evaporation data in a deciduous...

  15. Crayfish process leaf litter in tropical streams even when shredding insects are common

    OpenAIRE

    Coughlan, Jacqui; Pearson, R.G.; Boyero, Luz

    2010-01-01

    Comparisons of leaf-litter processing in streams suggest that tropical streams have fewer leaf shredders than temperate streams and that insect shredders might be replaced by other taxa such as Crustacea in tropical systems. Australian wet-tropical streams have abundant insect shredders, and also abundant crayfish, which may contribute to litter processing. We monitored litter input and retention in a Queensland rainforest stream to determine availability of litter in different seasons, and w...

  16. The Effect of the Litter Materials on Broiler Chickens Welfare and Performance

    Directory of Open Access Journals (Sweden)

    Serpil Gençoğlan

    2017-12-01

    Full Text Available The aim of this study is to review the quality and types of the litter material and its effect on the welfare and performance of the broiler chickens. Since the most suitable broiler rearing system is on the littered floor, the litter material is of great importance. Demand for litter material is also increasing, depending on the development in broiler production. Straws, wood shavings, and sawdust are widely used as litters material. Beside these, materials such as wheat, barley, rye, oats, sunflower, rice, hazelnut, maize, soya, peanut, cotton and sugarcane are used purely or mixed as a litters material. The quality of the litter is determined with the litter moisture, pH, ammonium nitrate content, caking level and water holding capacity. The ideal litter material should have a moisture content of 20-25%, a pH of 8-10, and ammonia content should not exceed 25 ppm. The thickness of the litter changes between 2 and 10 cm according to the type of the litter, and size of it should not exceed 0.6 cm. Increase in the litter moisture increases pH, NH3 concentration and caking. The type of litter material effects on the performance, welfare, health, behavior and product quality of broiler chickens. In addition, there are negative effects of litter materials on carcass defects, foot-leg problems, breast blisters or bruises, decrease in living power, and increase of microorganism development due to litter moisture, increase of gas and dust formation in poultry. These adverse effects cause large economic losses in intensive enterprises. For this reason, the quality and type of litter material is very important in broiler rearing.

  17. Toward a Harmonized Approach for Monitoring of Riverine Floating Macro Litter Inputs to the Marine Environment

    OpenAIRE

    González-Fernández, Daniel; Hanke, Georg

    2017-01-01

    A high percentage of the litter entering the marine environment is assumed to come from land-based sources, but freshwater litter inputs have not been quantified. The lack of data and knowledge on fluxes of riverine litter to the sea, i.e. quantities and sources, hinders implementation of appropriate environmental regulations and mitigation measures. Estimations of riverine litter inputs require a consistent and harmonized approach to gather comparable data. The visual observation of floating...

  18. Invasive amebiasis.

    Science.gov (United States)

    Grecu, F; Bulgariu, Teodora; Blanaru, Oana; Dragomir, C; Lunca, Claudia; Stratan, I; Manciuc, Carmen; Luca, V

    2006-01-01

    Digestive amoebiasis with his invasive form is an unusual pathology encountered in the temperate zone. This could lead to a life threatening complication: systemic amoebiasis. A 55-year-old male was treated successfully of systemic amoebiasis in a third referral hospital. The diagnosis was established based on epidemiology data and microscopical identification of trophozoites of Entamoeba histolytica. The amoebicidal, antibiotic and supportive treatments was firstly administrated. The clinical picture of intestinal amoebiasis raised from dysenteric syndrome to necrotizing enteritis. The bowel perforation with localized peritonitis was followed by chronic enteric fistula. Amoebic liver abscess, as the most frequent extraintestinal complication, was concomitantly diagnosed and treated. Urinary amoebiasis was considered as complication in the context of systemic dissemination: any other location could become a site of an amoebic abscess. Multidisciplinary approach was the successful key in the management of the patient, including antiparasitic therapy and antibiotic prophylaxis, intensive care and multiple surgical approaches. The diagnosis of digestive amoebiasis and systemic complication may be delayed in nonendemic areas, leading to advanced and complicated stages of the disease. The surgical approach is most efficiently to treat a large liver amoebic abscess and intraperitoneal collections.

  19. PHOTOSYNTHESIS AND YIELDS OF GRASSES GROWN IN SALINE CONDITION

    Directory of Open Access Journals (Sweden)

    E.D. Purbajanti

    2014-10-01

    Full Text Available The aim of this study was to know effects of saline condition to crop physiology, growth andforages yield. A factorial completed random design was used in this study. The first factor was type ofgrass, these were king grass (Pennisetum hybrid, napier grass (Pennisetum purpureum, panicum grass(Panicum maximum, setaria grass (Setaria sphacelata and star grass (Cynodon plectostachyus. Thesecond factor was salt solution (NaCl with concentration 0, 100, 200 and 300 mM. Parameters of thisexperiment were the percentage of chlorophyll, rate of photosynthesis, number of tiller, biomass and drymatter yield. Data were analyzed by analysis of variance and followed by Duncan’s multiple range testwhen there were significant effects of the treatment. Panicum grass had the highest chlorophyll content(1.85 mg/g of leaf. Photosynthesis rate of setaria grass was the lowest. The increasing of NaClconcentration up to 300 mM NaCl reduced chlorophyll content, rate of photosynthesis, tiller number,biomass yield and dry matter yield. Responses of leaf area, biomass and dry matter yield to salinitywere linear for king, napier, panicum and setaria grasses. In tar grass, the response of leaf area andbiomass ware linear, but those of dry matter yield was quadratic. The response of tiller number tosalinity was linear for all species.

  20. Climate Effects on Soil Carbon Sequestration in a Grass, Oak and Conifer Ecosystem of California

    Science.gov (United States)

    Pittiglio, S. L.; Zasoski, R.

    2007-12-01

    Dissolved organic matter (DOM) leaching from decomposing detritus accumulated above mineral soils is an important carbon (C) and nitrogen (N) flux that influences biogeochemical processes, C sequestration and the health of individual ecosystems. Previous studies have shown that the main process controlling DOM mobility in soils is sorption in the mineral horizons that adds to stabilized organic matter pools. The objective of this study was to determine the effect of temperature and incubation time on DOC and DON biodegradation and sorption in the mineral soil. Surface litter from a grass, oak and a conifer site were leached with deionized water for 5, 15 or 96 hours at 4, 20 or 30oC. The resulting DOM solutions were characterized using 13C NMR, XAD-8 resin and UV-vis spectroscopy. The biodegradable fraction (BDOC) of these solutions was quantified using inoculum from A horizon soils. The DOM solutions were also used in sorption experiments on A horizon soils. Supernatant from the A horizon sorption experiment was then used in a sorption experiment on Bt horizon soils and analyzed for BDOC using Bt horizon inoculum. The ability of the soils to adsorb DOC increased with increasing aromaticity in the DOC solution. Therefore, conifer DOM exhibited greater sorption than oak and grass DOM due to higher aromaticity. In all horizons, we observed net release of indigenous OM when OM-free solution was added. Net release of OM was greatest from the soils from the pine site, which had the greatest OM content among the soils we studied. ***Results still pending***

  1. Are nitrate exports in stream water linked to nitrogen fluxes in decomposing foliar litter?

    Science.gov (United States)

    Kathryn B. Piatek; Mary Beth. Adams

    2011-01-01

    The central hardwood forest receives some of the highest rates of atmospheric nitrogen (N) deposition, which results in nitrate leaching to surface waters. Immobilization of N in foliar litter during litter decomposition represents a potential mechanism for temporal retention of atmospherically deposited N in forest ecosystems. When litter N dynamics switch to the N-...

  2. The effect of birth weight of boars and litter size in which were 1 ...

    African Journals Online (AJOL)

    Eugenia

    2017-05-22

    May 22, 2017 ... The model for all evaluated traits included litter size, birth weight and litter size x birth weight interaction as a fixed effects and order parity of sows in which the litters were standardized as random effect. The significance of difference. (P) between means was determined using Duncan's multiple range test.

  3. A new conceptual model for the fate of lignin in decomposing plant litter

    NARCIS (Netherlands)

    Klotzbücher, T.; Kaiser, K.; Guggenberger, G.; Gatzek, C.; Kalbitz, K.

    2011-01-01

    Lignin is a main component of plant litter. Its degradation is thought to be critical for litter decomposition rates and the build-up of soil organic matter. We studied the relationships between lignin degradation and the production of dissolved organic carbon (DOC) and of CO2 during litter

  4. Succession of soil microarthropod communities during the aboveground and belowground litter decomposition processes

    NARCIS (Netherlands)

    Fujii, Saori; Takeda, Hiroshi

    2017-01-01

    The process of litter decomposition is driven by interactions among climate, litter quality, and decomposers. However, information about the soil animal community involved in fine-root litter decomposition remains limited. We compared the composition of the soil microarthropods involved in leaf and

  5. Effects of neonatal litter size and age on ovarian gene expression and follicular development in gilts

    Science.gov (United States)

    Gilts raised in small litters have greater ovulation rate, stay in the herd longer and produce more pigs. The objective was to understand how neonatal litter size affects gilt development. The hypothesis is that gilts reared in smaller litters have greater ovarian follicular development. Within 24 h...

  6. The use of beached bird surveys for marine plastic litter monitoring in Ireland

    NARCIS (Netherlands)

    Acampora, Heidi; Lyashevska, Olga; Franeker, van J.A.; O'Connor, I.

    2016-01-01

    Marine plastic litter has become a major threat to wildlife. Marine animals are highly susceptible to entanglement and ingestion of debris at sea. Governments all around the world are being urged to monitor litter sources and inputs, and to mitigate the impacts of marine litter, which is primarily

  7. Broiler excreta composition and its effect on wet litter : aspects of nutrition

    NARCIS (Netherlands)

    Hoeven-Hangoor, van der E.

    2014-01-01

    In commercial broiler farms, birds are usually housed on litter, composed of bedding materials like wood shavings. Wet litter is a condition in which the litter reaches its saturation threshold for water and cannot hold more moisture. It causes increased microbial activity and, as a result,

  8. Does Proximity to Subsurface Poultry Litter Affect Corn Seedling Survival and Growth?

    Science.gov (United States)

    Poultry litter provides a rich nutrient source for crops, but the usual practice of surface broadcasting litter can degrade water quality by allowing storm runoff to transport nutrients into streams and lakes, while much of the ammonia N escapes into the atmosphere. Subsurface application of litter...

  9. A simple mathematical method to estimate ammonia emission from in-house windrowing of poultry litter

    Science.gov (United States)

    In house windrowing between flocks is an emerging sanitary management practice to partially disinfect the built-up litter in broiler houses. Windrowing litter results in high litter temperatures that can reduce the risk of transmitting pathogens to next flock. Simultaneously, this practice may also ...

  10. Estimating litter carbon stocks on forest land in the United States

    Science.gov (United States)

    Grant M. Domke; Charles H. (Hobie) Perry; Brian F. Walters; Christopher W. Woodall; Matthew B. Russell; James E. Smith

    2016-01-01

    Forest ecosystems are the largest terrestrial carbon sink on earth, withmore than half of their net primary productionmoving to the soil via the decomposition of litter biomass. Therefore, changes in the litter carbon (C) pool have important implications for global carbon budgets and carbon emissions reduction targets and negotiations. Litter accounts for an estimated...

  11. Litter carbon stocks in forests of the US are markedly smaller than previously reported

    Science.gov (United States)

    Grant Domke; Charles Perry; Brian Walters; Christopher Woodall; Matthew Russell; James. Smith

    2015-01-01

    Forest ecosystems are the largest terrestrial carbon sink on earth with more than half of their net primary production moving to the soil via the decomposition of litter biomass. Therefore, changes in the litter carbon pool have important implications for global carbon budgets and carbon emissions reduction targets and negotiations. Litter accounts for an estimated 5...

  12. The Unintended Effects of a Posted Sign on Littering Attitudes and Stated Intentions.

    Science.gov (United States)

    Horsley, A. Doyne

    1988-01-01

    Compares the effect of two different anti-littering signs. Results suggest that the ambiguously worded litterbug sign was interpreted differently by individuals and that it did not encourage an anti-littering attitude or affect stated intention to litter. (CW)

  13. Production and decomposition of plant litter in an arid rangeland of ...

    African Journals Online (AJOL)

    Data on litter production and decomposition in an arid rangeland in Kenya was collected over a two-year period. Litter sampling was carried out at monthly intervals using a rectangular 0.25m-2 quadrat frame. Litter within the quadrats was handpicked and washed with running water to get rid of soil particles, dried, and ...

  14. Prevention of littering through packaging design : A support tool for concept generation

    NARCIS (Netherlands)

    Wever, R.; Gutter, N.; Silvester, S.

    2006-01-01

    Littering is a social and environmental problem. Numerous studies have been performed trying to understand littering behavior and to find ways to influence it successfully. Various litter-reduction strategies have been applied with changing success. These have either focused on directly influencing

  15. Does litter size affect emotionality, spatial learning and memory in piglets?

    NARCIS (Netherlands)

    Fijn, Lisa; Antonides, Alexandra; Aalderink, Dave; Nordquist, Rebecca E.; van der Staay, Franz Josef

    2016-01-01

    Average litter size has steadily increased over the past decades in the pig farming industry. Large litters are associated with an increase of piglets born with a lower birth weight and reduced overall piglet viability. The aim of our study was to investigate whether litter size affects

  16. Comparison of the abundance and composition of litter fauna in tropical and subalpine forests

    Science.gov (United States)

    G. Gonzalez; T.R. Seastedt

    2000-01-01

    In this study, we quantify the abundance and composition of the litter fauna in dry and wet tropical forests and north- and south-facing subalpine forests. We used the same litter species contained in litterbags across study sites to standardize for substrate conditions, and a single method of fauna extraction from the litter (Tullgren method). Fauna densities were...

  17. ANATOMIC STRUCTURE OF CAMPANULA ROTUNDIFOLIA L. GRASS

    Directory of Open Access Journals (Sweden)

    V. N. Bubenchikova

    2017-01-01

    Full Text Available The article present results of the study for a anatomic structure of Campanula rotundifolia grass from Campanulaceae family. Despite its dispersion and application in folk medicine, there are no data about its anatomic structure, therefore to estimate the indices of authenticity and quality of raw materials it is necessary to develop microdiagnostical features in the first place, which could help introducing of thisplant in a medical practice. The purpose of this work is to study anatomical structureof Campanula rotundifolia grass to determine its diagnostic features. Methods. Thestudy for anatomic structure was carried out in accordance with the requirements of State Pharmacopoeia, edition XIII. Micromed laboratory microscope with digital adjutage was used to create microphotoes, Photoshop CC was used for their processing. Result. We have established that stalk epidermis is prosenchymal, slightly winding with straight of splayed end cells. After study for the epidermis cells we established that upper epidermis cells had straight walls and are slightly winding. The cells of lower epidermishave more winding walls with prolong wrinkled cuticule. Presence of simple one-cell, thin wall, rough papillose hair on leaf and stalk epidermis. Cells of epidermis in fauces of corolla are prosenchymal, with winding walls, straight or winding walls in a cup. Papillary excrescences can be found along the cup edges. Stomatal apparatus is anomocytic. Conclusion. As the result of the study we have carried out the research for Campanula rotundifolia grass anatomic structure, and determined microdiagnostic features for determination of raw materials authenticity, which included presence of simple, one-cell, thin-walled, rough papillose hair on both epidermises of a leaf, along the veins, leaf edge, and stalk epidermis, as well as the presence of epidermis cells with papillary excrescences along the edges of leaves and cups. Intercellular canals are situatedalong the

  18. Prospects for Hybrid Breeding in Bioenergy Grasses

    DEFF Research Database (Denmark)

    Aguirre, Andrea Arias; Studer, Bruno; Frei, Ursula

    2012-01-01

    , we address crucial topics to implement hybrid breeding, such as the availability and development of heterotic groups, as well as biological mechanisms for hybridization control such as self-incompatibility (SI) and male sterility (MS). Finally, we present potential hybrid breeding schemes based on SI...... of different hybrid breeding schemes to optimally exploit heterosis for biomass yield in perennial ryegrass (Lolium perenne L.) and switchgrass (Panicum virgatum), two perennial model grass species for bioenergy production. Starting with a careful evaluation of current population and synthetic breeding methods...

  19. Upgrated fuel from reed canary grass

    Energy Technology Data Exchange (ETDEWEB)

    Oravainen, H. [VTT Energy, Jyvaeskylae (Finland)

    1997-12-01

    Results described in this presentation are from a large EU-project - Development of a new crop production system based on delayed harvesting and system for its combined processing to chemical pulp and biofuel powder. This is a project to develop the use of Reed Canary Grass (Phalaris Arundinaceae) both for pulp industry and energy production. The main contractor of the project is Swedish University of Agricultural Sciences (coordinator), task coordinators are United Milling Systems A/S from Denmark, and Jaakko Poeyry Oy and VTT Energy from Finland In addition, there are partners from several countries participating in the project

  20. Grass-on-grass competition along a catenal gradient in mesic ...

    African Journals Online (AJOL)

    Three aboveground treatments (full light competition, no light competition and clipping to simulate grazing), and two belowground treatments (full belowground competition and belowground competition excluded by a root tube), were used. On all soil depths the three grass species differed in mean mass, with E. racemosa ...

  1. Nutritional value of cabbage and kikuyu grass as food for grass carp ...

    African Journals Online (AJOL)

    weighing). Fish were fed once a-day. The feed refusal was measured daily by siphoning out the debris on the bottom of the aquaria which was collected on a sieve .... raising grass carp without the need for supplementary feeding. Cabbage is widely produced on both a subsis- tence and commercial scale by local farmers.

  2. Treatment of grass pollen allergy: focus on a standardized grass allergen extract – Grazax®

    Directory of Open Access Journals (Sweden)

    Moisés Calderón

    2008-11-01

    Full Text Available Moisés Calderón1, Tove Brandt21Section of Allergy and Clinical Immunology, Royal Brompton Hospital, Imperial College, NHLI, London, UK; 2Group Clinical Development, ALK-Abelló A/S, Hørsholm, DenmarkAbstract: Immunotherapy is the only treatment for allergy that has the potential to alter the natural course of the disease. Sublingual immunotherapy (SLIT for grass pollen-induced rhino-conjunctivitis has been developed to make immunotherapy available to a broader group of allergic patients. In the largest clinical programme ever conducted with allergen-specific immunotherapy, over 1,700 adults and 260 children have been exposed to Grazax®. Grazax is formulated as an oral lyophilisate (tablet for sublingual administration, containing 75,000 SQ-T standardized allergen extract of grass pollen from Phleum pratense. Grazax is indicated for treatment of grass pollen-induced rhinitis and conjunctivitis in adult patients with clinically relevant symptoms and diagnosed with a positive skin prick test and/or specific IgE test to grass pollen. In phase I trials doses from 2,500 to 1,000,000 SQ-T were tested. All doses were well tolerated and 75,000 SQ-T, with approximately 15 µg major allergen protein, was chosen as the optimal dose. Three phase III trials are ongoing, one being a long-term trial. Results from GT-08 trial first and second treatment years showed a reduction of 30% and 36%, respectively, in daily rhino-conjunctivitis symptom scores and a reduction of 38% and 46% of daily rhinoconjunctivitis medication scores compared with placebo over the entire grass pollen season. Subjects treated with Grazax also had an increased number of well days and improved quality of life, and more subjects experienced excellent rhino-conjunctivitis control. The most common adverse events related to Grazax are local reactions, such as pruritus, edema mouth, ear pruritus, throat irritation, and sneezing. We conclude that Grazax is efficacious and safe for treatment

  3. INTERACTION EFFECT OF TREE LEAF LITTER, MANURE AND

    African Journals Online (AJOL)

    Compound D (8N-l4P-7K) fertilizer (300 kg ha"), and their combinations on maize growth and yield on ... presence of fertilizer. It is hypothesised that the application of Leucaena, manure and miombo litter resulted in immobilisation of nutrients. Leucaena, which is rich in N but low in P, probably .... No lime was applied to the.

  4. Beach litter sourcing: A trawl along the Northern Ireland coastline.

    Science.gov (United States)

    Williams, A T; Randerson, P; Allen, C; Cooper, J A G

    2017-09-15

    Fourteen non-recreational coastal locations in Northern Ireland were investigated as to whether beach litter deposition was related to seasonal or site specific factors. Litter items were counted in 100m width transects and 1km strand-line surveys over a five-season period (autumn to autumn). Survey sites comprised fishing ports; estuarine areas, north (high energy) and east coast (low energy) beaches. Fishing ports accumulated the most litter. In the 100m beach surveys, plastics, string and cord, bottle caps, food items, rope, and drink containers dominated. In strand-line surveys, large plastic pieces were dominant, followed by rope, string and cord, strapping bands (absent on beach surveys), cloth, wood (mainly pallets, fish boxes) and metal items. Multivariate analyses revealed major litter category differences between the ports and all other sites, with a lesser distinction between exposed and estuarine sites. There was no simple coastline trend and no apparent effect of seasonality between samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Ensilage Of Sugarcane Tops Using Urea And Broiler Litter Additives ...

    African Journals Online (AJOL)

    Wilted SCT (50% DM) was ensiled in the laboratory using a SemiMicro technique with PVC silos. Treatments comprised graded levels of urea (4%, 8%, 12%) and poultry (broiler) litter (BL) (10%, 20%, 30%). The quality of the silages was assessed after 42d storage. The SCT-urea silages were alkaline, with increasing pH, ...

  6. Changes in lignin content of leaf litters during mulching.

    Science.gov (United States)

    Jin, Zhenfu; Akiyama, Takuya; Chung, Byung Yeoup; Matsumoto, Yuji; Iiyama, Kenji; Watanabe, Satomi

    2003-11-01

    Alkaline nitrobenzene oxidation, ozonation and methoxyl content determinations were applied to decomposing leaf litter of Ginkgo biloba L., Cinnamomum camphora sieb., Zelkova serrata Makino and Firmiana simplex W. F. Wight, respectively, during mulching to investigate the properties and estimate changes in lignin composition and content. Since the Klason lignin residue originated from components highly resistant to degradation by acid, the methoxyl content of Klason residue was used to estimate the lignin content of leaf litter. Quantitative analysis of presumed lignin-derived fragments, by use of alkaline nitrobenzene oxidation and ozonation methods, suggested that the estimated lignin content approximates that of the real lignin content of leaves, which is greatly overestimated by the Klason procedure. The estimated lignin contents ranged from 3.9 to 10.0% while the Klason lignan residue varied from 37.1 to 46.7% in un-mulched leaf litter. The absolute amounts of the measured lignin somewhat decreased during mulching, while the structure of lignin remaining in leaf litters after mulching was considered not to be very different from its original structure.

  7. Spatial variability of heating profiles in windrowed poultry litter

    Science.gov (United States)

    In-house windrow composting of broiler litter has been suggested as a means to reduce microbial populations between flocks. Published time-temperature goals are used to determine the success of the composting process for microbial reductions. Spatial and temporal density of temperature measurement ...

  8. Functional leaf attributes predict litter decomposition rate in herbaceous plants

    NARCIS (Netherlands)

    Cornelissen, J. H C; Thompson, K.

    1997-01-01

    We tested the hypothesis that functional attributes of living leaves provide a basis for predicting the decomposition rate of leaf litter. The data were obtained from standardized screening tests on 38 British herbaceous species. Graminoid monocots had physically tougher leaves with higher silicon

  9. Forest litter insect community succession in clearcuts of Norway spruce

    Science.gov (United States)

    Arturas Gedminas

    2003-01-01

    Insects are subjected to stress in fresh clearcuts due to changes in microclimate, vegetation, and trophic links. The objective of this study was to investigate succession in litter insect communities (most abundant by number of species and individuals of all clearcut insects).

  10. Carcass characteristics and meat quality of rabbit litters from rabbit ...

    African Journals Online (AJOL)

    The effect of restricted feeding and realimentation during pregnancy was studied to know the carryover effect on carcass characteristics and meat quality of rabbit litters.Young does fed ad libitum diets often show parturition problems (Dystokia and abnormal presentation) with the subsequent reduction of number of kits, ...

  11. Fungal community on decomposing leaf litter undergoes rapid successional changes

    Czech Academy of Sciences Publication Activity Database

    Voříšková, Jana; Baldrian, Petr

    2013-01-01

    Roč. 7, č. 3 (2013), s. 477-486 ISSN 1751-7362 R&D Projects: GA MŠk(CZ) ME10152; GA MŠk LD12050; GA ČR GAP504/12/0709 Institutional support: RVO:61388971 Keywords : fungi * litter decomposition * cellulose Subject RIV: EE - Microbiology, Virology Impact factor: 9.267, year: 2013

  12. Influence of poultry litter and double cropping on soybean yield

    Science.gov (United States)

    Continuous cultivation of mono-cropping systems coupled with inorganic fertilizer consumption has led to a decline in soil fertility, negatively influencing crop yields. Poultry litter application and double cropping are two management practices that could be used with conservation tillage to increa...

  13. Litter-of-origin trait effects on gilt development

    Science.gov (United States)

    The preweaning litter environment of gilts can affect subsequent development. In a recent experiment designed to test the effects of diet on gilt development, individual birth weights, immunocrits, sow parity, number weaned, and individual weaning weights were collected for gilts during the preweani...

  14. Psycho-sociocultural Analysis of Attitude towards Littering in a ...

    African Journals Online (AJOL)

    This study examined the influence of altruism, environmental self-efficacy, locus of control, self-concept, age, gender, and level of education as predictors of attitude towards littering among residents of some selected communities in Ibadan metropolis. An ex-post cross-sectional research design was adopted for this study.

  15. The social costs of marine litter along European coasts

    NARCIS (Netherlands)

    Brouwer, R.; Hadzhiyska, D.; Ouderdorp, H.

    2017-01-01

    This is the first study to assess the social costs of marine debris washed ashore and litter left behind by beach visitors along different European coasts. Three identical surveys, including a discrete choice experiment, are implemented at six beaches along different European coastlines: the

  16. Incorporation of microplastics from litter into burrows of Lumbricus terrestris

    NARCIS (Netherlands)

    Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.; Salanki, T.E.; Ploeg, van der M.; Besseling, E.; Koelmans, A.A.; Geissen, V.

    2017-01-01

    Pollution caused by plastic debris is an urgent environmental problem. Here, we assessed the effects of microplastics in the soil surface litter on the formation and characterization of burrows built by the anecic earthworm Lumbricus terrestris in soil and quantified the amount of microplastics that

  17. Screening of seven microsatellite markers for litter size in Xinong ...

    African Journals Online (AJOL)

    Jane

    2011-08-08

    Aug 8, 2011 ... microsatellite loci. The number of effective alleles (Ne), polymorphism information content (PIC) and average heterozygosity (He) were the highest at OarFCB11 and the lowest at OarAE129 in Xinong. Saanen dairy goat. The analysis of the effect of the six polymorphisms microsatellite loci on the litter size of ...

  18. Screening of seven microsatellite markers for litter size in Xinong ...

    African Journals Online (AJOL)

    The number of effective alleles (Ne), polymorphism information content (PIC) and average heterozygosity (He) were the highest at OarFCB11 and the lowest at OarAE129 in Xinong Saanen dairy goat. The analysis of the effect of the six polymorphisms microsatellite loci on the litter size of Xinong Saanen dairy goat indicated ...

  19. Observations on litter size, parturition and maternal behaviour in ...

    African Journals Online (AJOL)

    Observations on litter size, parturition and maternal behaviour in relation to lamb mortality in fecund Dormer and South African Mutton Merino ewes. S.W.P. Clcete. Eisenburg Agricultural Centre, Private Bag, Eisenburg, 7607 Republic of South Africa. Dormer (n = 166) and SA Mutton Merino (n = 147) ewes were observed ...

  20. The Determinants of Littering Attitude in Urban Neighbourhoods of Jos

    African Journals Online (AJOL)

    In Nigeria, the challenge of effective refuse collection and disposal by the appropriate authorities has made littering behavior an environmental hazard that is detrimental to human health. Given the prevalence of refuse in our communities, this paper using the survey method examined if prevalent attitude and place of ...