نتایج جستجو برای: including steppe
تعداد نتایج: 976436 فیلتر نتایج به سال:
We present a record of pollen and spores coprophilous fungi from sediment core Auel infilled maar, Eifel, Germany, covering the period 42,000 to 36,000 yr b2k. can show that vegetation cover was dominated by boreal forest with components steppe cold-temperate wood taxa. The proportion taxa higher during interstadials, whereas steppe-vegetation became more prominent stadials. During Heinrich sta...
Species interactions form food webs, impacting community structure and, potentially, ecological dynamics. It is likely that global climatic perturbations that occur over long periods of time have a significant influence on species interaction patterns. Here, we integrate stable isotope analysis and network theory to reconstruct patterns of trophic interactions for six independent mammalian comm...
The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 ...
Soil bacteria play a key role in the ecological and evolutionary responses of agricultural ecosystems. Domestic herbivore grazing is known to influence soil bacterial community. However, the effects of grazing and its major driving factors on soil bacterial community remain unknown for different plant community compositions under increasing grazing intensity. Thus, to investigate soil bacterial...
A changing precipitation regime and increasing nitrogen deposition are likely to have profound impacts on arid and semiarid ecosystem C cycling, which is often constrained by the timing and availability of water and nitrogen. However, little is known about the effects of altered precipitation and nitrogen addition on grassland ecosystem C exchange. We conducted a 3-year field experiment to asse...
Outbreaks of plague in wildlife are sporadic and spatially dispersed, and they depend on coincidence of susceptible hosts, flea vectors, the plague bacterium (Yersinia pestis), and environmental factors that support pathogen transmission. We fit spatial models of plague outbreaks to a long-term data set (1981–2005) of towns of black-tailed prairie dogs (Cynomys ludovicianus) on the shortgrass s...
Badger (Taxidea taxus) disturbances increase soil heterogeneity in a degraded shrub-steppe ecosystem
In the western United States, overgrazing, weed invasion and wildfire have resulted in the conversion of shrub-steppe to annual grasslands, with substantial effects on ecosystem function. In these landscapes, badgers disturb large areas of soil while foraging for fossorial animals. Mounds created by badgers contained the lowest concentrations of total carbon, nitrogen and sulphur, mineral nitro...
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