نتایج جستجو برای: species evenness

تعداد نتایج: 548668  

اسحاقی راد, جواد , خانعلیزاده, آمنه ,

The aim of present study was comparison of plant diversity in managed and control compartments of Jamand district in Noshahr (Mazandaran province). Random-systematic sampling method with network dimension of 100×200 m was used to locate samples. Sampling plot area was 400 m2 to survey woody species and 100 m2 plots was set up to herbaceous species (in the center of main plots). At each sample p...

Journal: :journal of rangeland science 0
mohsen sharafatmandrad natural resources department, rangeland and watershed management section, university of jiroft, jiroft, iran hossein naderi faculty of rangeland and watershed management, gorgan university of agricultural sciences and natural resources

biodiversity plays a crucial role in stability and productivity of natural ecosystem. the main goal of this research was to classify ecological groups in steppe rangeland and investigate their relationships with plant diversity indices. therefore, fifty different land unit tracts (lut) were identified in khod-neuk basin, yazd province, iran, in 2010. vegetation and soil samples were taken in th...

This study was carried out in managed and unmanaged Fagus orientalis L. (beech) stands in the Asalem beech forest in order to compare the composition and diversity of plant species. Three V-shaped catena landforms were selected for each stand. Then, large quadrats, 400 m2 area, with selective method and within each of them, small quadrats, 4 m2 area, were established along each catena and slope...

Journal: :حفاظت گیاهان 0
زهره خسرویان چترودی حسین صادقی نامقی مجتبی حسینی

pollination and pest control are perhaps the best-known ecological services performed by hover flies. the species diversity and their abundance have an influential impact on the ecological services provided by this family. to find out species diversity of adult flower flies associated with agroecosystems in kerman province, a biodiversity survey using insect net and color water traps was conduc...

2010
Uffe N. Nielsen Graham H. R. Osler Colin D. Campbell Roy Neilson David F. R. P. Burslem René van der Wal

BACKGROUND "The enigma of soil animal species diversity" was the title of a popular article by J. M. Anderson published in 1975. In that paper, Anderson provided insights on the great richness of species found in soils, but emphasized that the mechanisms contributing to the high species richness belowground were largely unknown. Yet, exploration of the mechanisms driving species richness has fo...

Journal: :The American naturalist 2004
M Forrest Hill Jon D Witman Hal Caswell

We present a Markov chain model of succession in a rocky subtidal community based on a long-term (1986-1994) study of subtidal invertebrates (14 species) at Ammen Rock Pinnacle in the Gulf of Maine. The model describes successional processes (disturbance, colonization, species persistence, and replacement), the equilibrium (stationary) community, and the rate of convergence. We described succes...

2008
Laura Taylor-Taft Stan Faeth

While many studies have shown that urbanization and land-use type significantly impact species richness and evenness, few studies have investigated the mechanisms by which these changes occur. A residential neighborhood at ASU-Polytechnic Campus has been designed with 4 different neighborhood landscape regimes and provides the ideal opportunity to explore how local neighborhood landscaping affe...

2010
Lou Jost

Contrary to common belief, decomposition of diversity into independent richness and evenness components is mathematically impossible. However, richness can be decomposed into independent diversity and evenness or inequality components. The evenness or inequality component derived in this way is connected to most of the common measures of evenness and inequality in ecology and economics. This pe...

Journal: :Journal of environmental biology 2011
S Rajashekara M G Venkatesha

Observations were made on the occurrence, abundance, richness, and diversity of waterbirds in 15 major lakes in Bangalore city during 2008 - 2009. During the study period 35 species of aquatic birds were recorded. The number of aquatic bird species recorded at various lakes ranged from 23 to 35. The percent abundance of waterbirds recorded in the study lakes ranged from 2.46 to 21.49 and itwas ...

Journal: :Ecology 2009
Daniel J McGlinn Michael W Palmer

Recent empirical work in numerous systems has demonstrated the interdependence of spatial and temporal accumulation of species in the species-time-area relationship (STAR). The purpose of this study was to develop a process-based stochastic model for the STAR that assumes species neutrality and to compare the model's expectations to data collected on plant species in a tallgrass prairie. We var...

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