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Grassland Plant Communities (grassland + plant_community)

Distribution by Scientific Domains

Life Sciences	40%

Selected Abstracts

Effects of Native and Non-Native Grassland Plant Communities on Breeding Passerine Birds: Implications for Restoration of Northwest Bunchgrass Prairie

RESTORATION ECOLOGY, Issue 4 2009
Patricia L. Kennedy
Abstract One common problem encountered when restoring grasslands is the prominence of non-native plant species. It is unclear what effect non-native plants have on habitat quality of grassland passerines, which are among the most imperiled groups of birds. In 2004 and 2005, we compared patterns of avian reproduction and the mechanisms that might influence those patterns across a gradient of 13 grasslands in the Zumwalt Prairie in northeastern Oregon that vary in the degree of non-native plant cover (0.9,53.4%). We monitored the fate of 201 nests of all the breeding species in these pastures and found no association of percent non-native cover with nest densities, clutch size, productivity, nest survival, and nestling size. Regardless of the degree of non-native cover, birds primarily fed on Coleoptera, Orthoptera, and Araneae. But as percent non-native cover in the pastures increased, Orthoptera made up a greater proportion of diet and Coleoptera made up a smaller proportion. These diet switches were not the result of changes in terrestrial invertebrate abundance but may be related to decreases in percent bare ground associated with increasing cover of non-native vegetation. Measures of nest crypticity were not associated with cover of non-native vegetation, suggesting that predation risk may not increase with increased cover of non-native vegetation. Thus, the study results show that increased non-native cover is not associated with reduced food supplies or increased predation risk for nesting birds, supporting the growing body of evidence that grasslands with a mix of native and non-native vegetation can provide suitable habitat for native grassland breeding birds. [source]

Effects of raised water levels on wet grassland plant communities

APPLIED VEGETATION SCIENCE, Issue 3 2009
Sarah E. Toogood
Abstract Questions: What are the effects of raised water levels on wet grassland plant communities and dynamics? To what extent do time since raised water levels, vegetation management and water regime influence community composition? Location: Pevensey Levels, southeast England, UK. Methods: Plant communities and hydrology were monitored during 2001-03 within 23 wet grassland meadows and pastures where water levels had been raised for nature conservation at different times over 21 years. Community variations were examined using species abundance and ecological traits. Results: Water regime, measured as duration of flooding, groundwater level and soil moisture was significantly related to plant community variation. Communities were divided into grasslands where inundation was shallow (,8 cm) and relatively short (,3 months) and sites where deeper flooding was prolonged (,5 months), supporting a variety of wetland vegetation. With increasing wetness, sites were characterised by more bare ground and wetland plants such as sedges, helophytes and hydrophytes, and species with a stress-tolerating competitive strategy. All sites showed considerable annual dynamics, especially those with substantially raised water levels. There were no significant relationships between time since water levels were raised and plant community composition. Grassland management exerted a limited influence upon vegetation compared to water regime. Conclusions: Grassland plant communities are responsive to raised water levels and have potential for a rapid transition to wetland vegetation, irrespective of grazing or cutting management. Creation or restoration of wet grasslands by (re)wetting is feasible but challenging due to the high dynamism of wetland plant communities and the need for substantially raised water levels and prolonged flooding to produce significant community changes. [source]

Arbuscular mycorrhizal fungi and water table affect wetland plant community composition

JOURNAL OF ECOLOGY, Issue 5 2006
BENJAMIN E. WOLFE
Summary 1Most studies of the community-level effects of arbuscular mycorrhizal fungi (AMF) have been conducted in upland grassland plant communities where a majority of the plant species are colonized by AMF. Here, we examine the effects of AMF on plant community composition in experimental wetland plant communities, where the dominant plant species are non-mycorrhizal and subordinate plant species are colonized by AMF. We also assess how an important abiotic soil variable, depth to water table (soil saturation), might mediate the community-level effects of AMF. 2In the low water table (un-saturated) treatment, above-ground plant biomass increased in the presence of AMF relative to the controls, while in the high water table treatment, biomass decreased with the presence of AMF. Contrary to predictions, plant diversity was unaffected by the presence of AMF in the low water table treatment, but significantly decreased in the presence of AMF in the high water table treatment. Changes in biomass and composition were driven by the interactions between the dominant non-mycorrhizal species Carex hystercina, and the remaining mycorrhizal plant species. 3Our results indicate that AMF have the potential to influence plant community composition in calcareous fens and that these effects can be mediated by soil saturation. 4This study has implications for understanding how established principles of above-ground/below-ground interactions from upland communities translate to wetland plant communities and for understanding how AMF function can be mediated by abiotic soil properties. Contrary to previous thought, AMF may be important drivers of plant community composition in wetland plant communities. [source]