نتایج جستجو برای: cover plants
تعداد نتایج: 304850 فیلتر نتایج به سال:
Excessive herbivory can have transformative effects on forest understory vegetation, converting diverse communities into depauperate ones, often with increased abundance of non-native plants. White-tailed deer are a problematic herbivore throughout much of eastern North America and alter forest understory community structure. Reducing (by culling) or eliminating (by fencing) deer herbivory is e...
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...
in order to evaluate the effects of cover crops on reduced weed biomass in hybrid sunflower an experiment was carried in the research stations, natural resources medicinal plants (samian_ardabile) with 3 replicates in 1390-1391. the first factor was considered three type of cover crops, winter rye, spring barley, winter wheat with 2 control treatment, second factor was mulch management at two l...
Question: We present a general structural carbon nutrient balance hypothesis parallel to Bryant et al.’s defensive chemistry hypothesis. Our hypothesis suggests that because herb species require a lower investment of carbon per unit length of stem than do woody plants, herbs should be at a competitive advantage where the leaf area of plants in the ground layer is limited by light (or fixed carb...
Herbivores can profoundly influence plant species assembly, including plant invasion, and resulting community composition. Population increases of native herbivores, e.g. white-tailed deer (Odocoileus virginianus), combined with burgeoning plant invasions raise concerns for native plant diversity and forest regeneration. While individual researchers typically test for the impact of deer on plan...
abstract. rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. accordingly, data collection and measurements for evalu...
this research has been done with the aim of explaining environmental and managerial factors that affects on rangeland vegetation distribution in saral rangelands of kurdistan province. after selecting plant types as working area were done sampling from plant types and determined some of plants parameters such as kind and number of plants and cover percentage. various environmental factors such ...
L and-use change in the United States represents an enormous uncontrolled experiment in the ways habitat changes influence plants and animals. When cities were built, land was plowed, or forests were cut, the effects on our native biota were not considered. Of course, humans have influenced the flora and fauna of North America over the ages. Native Americans established settlements, practiced a...
abstract soil, is a reclamable and sustainable source. it is the basis of survival and it’s implication, should be performed on the basis of productivity identification according to scientific and technical rules, we can protect this valuable source, and increase it’s productivity and usage. nowdays, saline soils cover nearly 14.6% of the country area. study areas (kashan’ playa) have saline an...
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