نتایج جستجو برای: richness margalef
تعداد نتایج: 20862 فیلتر نتایج به سال:
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 ...
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...
I performed an exploratory analysis of four broad-scale hypotheses (area availability, energy availability, habitat heterogeneity and geometric constraints) for changes in species richness over Central American mayfly species, and compared their outcomes at different taxonomic levels. I employed an eigenvector-based spatial filtering to control spatial autocorrelation effects and conducted mult...
The number of microbial operational taxonomic units (OTUs) within a community is akin to species richness within plant/animal ("macrobial") systems. A large literature documents OTU richness patterns, drawing comparisons to macrobial theory. There is, however, an unrecognized fundamental disconnect between OTU richness and macrobial theory: OTU richness is commonly estimated on a per-individual...
This study maps distribution and spatial congruence between Above-Ground Biomass (AGB) and species richness of IUCN listed conservation-dependent and endemic avian fauna in Palawan, Philippines. Grey Level Co-Occurrence Texture Matrices (GLCMs) extracted from Landsat and ALOS-PALSAR were used in conjunction with local field data to model and map local-scale field AGB using the Random Forest alg...
What are the local community consequences of changes in regional species richness and composition? To answer this question we followed the assembly of microarthropod communities in defaunated areas of moss, embedded in a larger moss "region." Regions were created by combining moss from spatially distinct sites, resulting in regional species pools that differed in both microarthropod richness an...
Dryland ecosystems are highly vulnerable to climatic and land-use changes, while the mechanisms underlying patterns of dryland species richness are still elusive. With distributions of 3637 native vascular plants, 154 mammals, and 425 birds in Xinjiang, China, we tested the water-energy dynamics hypothesis for species richness patterns in Central Asian drylands. Our results supported the water-...
The arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local-regional species richness relationship was assessed over relative...
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