نتایج جستجو برای: content richness
تعداد نتایج: 434052 فیلتر نتایج به سال:
Arctic plant communities are altered by climate changes. The magnitude of these alterations depends on whether species distributions are determined by macroclimatic conditions, by factors related to local topography, or by biotic interactions. Our current understanding of the relative importance of these conditions is limited due to the scarcity of studies, especially in the High Arctic. We inv...
Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness?
Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. However, global-scale tests of this assumption have been elusive because of the focus on exotic species richness, rather than relative abundance. This is problematic because low invader richness can indicate invasion resistance by the native community or, alternatively, dominance b...
a r t i c l e i n f o Keywords: Acoustic sensing Biodiversity monitoring Species richness Acoustic sampling Automated bird call analysis Ecological indices Interpreting acoustic recordings of the natural environment is an increasingly important technique for ecologists wishing to monitor terrestrial ecosystems. Technological advances make it possible to accumulate many more recordings than can ...
Federal mandates to increase biofuel production in North America will require large new tracts of land with potential to negatively impact biodiversity, yet empirical information to guide implementation is limited. Because the temperate grassland biome will be a production hotspot for many candidate feedstocks, production is likely to impact grassland birds, a group of major conservation concer...
Background. Up to 75% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to d...
Testing Media Richness Theory in the New Media: The Effects of Cues, Feedback, and Task Equivocality
Media richness theory argues that performance improves when team members use “richer” media for equivocal tasks. This experiment studied the effects of media richness on decision making in two-person teams using “new media” (i.e., computer-mediated and video communication). Media richness was varied based on multiplicity of cues and immediacy of feedback. Subjects perceived differences in richn...
Many researchers hypothesize that plant richness declines at high soil fertility (and high productivity) due to light limitation. We tested this hypothesis in an old-field by independently manipulating fertilization and light levels via shade cloth (decreased light), vegetation tie-backs (increased light) and vegetation clipping (increased light). Droughts occurred during two of the four years ...
the study was performed for assess the environmental factors affecting weed species diversity and composition of wheat (triticum aestivum l.) fields in jajarm, north-khorasan of iran, in 2009. the crop management (herbicide, amount of nitrogen applied and preceding crop type) and edaphic factors (ph, texture and content of phosphorus) of 16 fields were collected. shannon’s diversity index, spec...
Biological diversity and species richness have been declined throughout the world as a result of human activities. Measuring species richness is important in rangeland conservation to evaluate the status and trends of native plant species, detecting non-native species invasion and monitoring rare species. However, heterogeneity in plant distribution makes inventories difficult. In this study tw...
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