نتایج جستجو برای: species richness

تعداد نتایج: 556166  

2012
SOPHIA QIAN NIU MICHAEL P. FRANCZYK JASON H. KNOUFT

1. Local assemblage structure, from a deterministic perspective, is presumably dictated by the regional species pool as well as regulated by local factors. We examined the relationships of the regional species pool and local hydrological characteristics to local species richness of North American freshwater fishes using data sets collected during the National Water Quality Assessment program co...

This study investigates the role of man-made disturbance on on nitrogen and phosphorus nutrient storage by herbaceous species in Gall Oak stands of Lorestan province. In order to do this study, two sites with the same physiographic and ecological conditions and different land uses were selected. Multiscale sampling plots were used randomly in each site to collect data on forest floor vegetation...

Journal: رستنیها 2019

Little attention has been devoted to lichens of Kerman province (Iran). This study was conducted to identify lichens in the Kuh-Asiab protected area of Kubanan located in the northernmost part of Kerman province. In this study, eight sites were chosen in the area. Sampling was carried out according to Random method. Height data were obtained from each site along with the abundance of lichen spe...

Journal: :Journal of Biogeography 2015

Journal: :The American naturalist 2001
N M Haddad D Tilman J Haarstad M Ritchie J M Knops

We experimentally separated the effects of two components of plant diversity-plant species richness and plant functional group richness-on insect communities. Plant species richness and plant functional group richness had contrasting effects on insect abundances, a result we attributed to three factors. First, lower insect abundances at higher plant functional group richness were explained by a...

Adel Sepehry Hossein Barani Mohsen Sharafatmandrad,

In arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. A study was done to analyze the effects of grazing on plant species diversity and Plant Functional Types‘ (PFTs) diversity of arid and semi-arid rangelands. We analyzed plant richness and diversity data from 75 sa...

نیکوی, مهرداد, همرنگ, نازنین, پوربابائی, حسن,

  Information about gaps and their sizes distribution is useful for protecting herbaceous diversity. This study was conducted to investigate the effect of gap size on herbaceous species diversity in oriental beech (Fagus orientalis Lipsky.) stand in Asalem, Guilan province. For this study, fifteen gaps in small, medium, and large sizes were randomly selected. Then, herbaceous species were ident...

2009
Rafael D. Loyola

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...

Journal: :Global Ecology and Biogeography 2014

2014
Steve Wathen James H. Thorne Andrew Holguin Mark W. Schwartz

Evidence for significant losses of species richness or biodiversity, even within protected natural areas, is mounting. Managers are increasingly being asked to monitor biodiversity, yet estimating biodiversity is often prohibitively expensive. As a cost-effective option, we estimated the spatial and temporal distribution of species richness for four taxonomic groups (birds, mammals, herpetofaun...

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