نتایج جستجو برای: biotic cover
تعداد نتایج: 122253 فیلتر نتایج به سال:
Identifying suitable genetic stock for restoration often employs a 'best guess' approach. Without adaptive variation studies, restoration may be misguided. We test the extent to which climate in central US grasslands exerts selection pressure on a foundation grass big bluestem (Andropogon gerardii), widely used in restorations, and resulting in local adaptation. We seeded three regional ecotype...
Originally from Asia, Rubus niveus has become one of the most widespread invasive plant species in the Galapagos Islands. It has invaded open vegetation, shrubland and forest alike. It forms dense thickets up to 4 m high, appearing to displace native vegetation, and threaten the integrity of several native communities. This study used correlation analysis between a R. niveus cover gradient and ...
Environmental indicators of macroinvertebrate and fish assemblage integrity in urbanizing watersheds
Urbanization compromises the biotic integrity and health of streams, and indicators of integrity loss are needed to improve assessment programs and identify mechanisms of urban effects. We investigated linkages between landscapes and assemblages in 31 wadeable Piedmont streams in the Etowah River basin in northern Georgia (USA). Our objectives were to identify the indicators of macroinvertebrat...
The influence of environmental factors on biotic responses to nutrients was examined in three diverse agricultural regions of the United States. Seventy wadeable sites were selected along an agricultural land use gradient while minimizing natural variation within each region. Nutrients, habitat, algae, macroinvertebrates, and macrophyte cover were sampled during a single summer low-flow period ...
The factors that influence the invasion of natural habitats by nonnative plants remain poorly understood. We investigated abiotic, biotic, and human influences on the distribution and abundance of nonnative species in coastal upland habitats of southern New England and adjacent New York, US. We censused vegetation and sampled soils in 776, 20 · 20 m plots in natural areas and constructed a spat...
The continuing warming of the climate system is reducing snow cover depth and duration worldwide. Changes in can significantly affect soil microclimate functioning many terrestrial ecosystems across latitudinal elevational gradients. Yet, a quantitative assessment effects change on physicochemical biotic properties at large or regional scales lacking. Here, we synthesized data 3286 observations...
Some riparian areas of the country are in danger of deterioration due to uncontrolled exploitation coupled with loose implementation of environmental protection policies and regulations. Muleta River, a major watershed in Bukidnon, Philippines, was assessed to determine the present condition of its riparian habitat. Abiotic and biotic conditions of the river were assessed. Other factors includi...
Old fields are diverse forb-dominated ecosystems transitioning into woody-dominated forested ecosystems. However, the susceptibility of old fields to high levels of plant invasion can lead to the co-occurrence of multiple non-native invasive plant species at the fine-scale of plant neighborhoods, which can alter native species co-occurrence patterns and successional trajectories into forest com...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید