نتایج جستجو برای: richness margalef index

تعداد نتایج: 415206  

Journal: :International Journal of Plant and Soil Science 2021

An extensive survey was carried to study the diversity of predators associated with mealybug complex in cassava growing districts viz., Salem, Namakkal, Erode, Tiruppur and Coimbatore Tamil Nadu, India from January September, 2021. The revealed dominance Phenacoccus manihoti Matile-Ferrero 1977 (Hemiptera: Pseudococcidae) than other species all surveyed districts. incidence P. ranged 12 90 per ...

2010
Christy M McCain John-Arvid Grytnes

The abiotic and biotic gradients on mountains have enormous potential to improve our understanding of species distributions, species richness patterns and conservation. Here we describe how abiotic factors change with elevation, how flora and fauna respond to these changes and how elevational species richness patterns have been studied to uncover drivers of biodiversity. There are four main tre...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

the evaluation of the edge effects of forest roads on ecosystem is very useful to understand changes from forest road. with this regard, in this research the effect of main forest road construction on regeneration and biodiversity of established trees in edge of forest road was investigated at 35 m distance into forest area. an existing 10 years old road segment, with same physiographic propert...

2004
R. Biggs R. J. Scholes B. Reyers

The Southern Africa Millennium Ecosystem Assessment developed an index for quantifying the state of biodiversity. The Biodiversity Intactness Index (BII) operates at the species level, and is based on changes in species abundance, rather than changes in richness brought about by extinction. The BII uses spatial data on species richness and land use activities per ecosystem type to weight estima...

جعفری, فرهنگ , زارع‌کیا, صدیقه, غلامی, پرویز , فیاض, محمد, گودرزی, محمود ,

Livestock grazing is a common human-induced activity with direct and indirect effects even on the ecosystems of protected areas. The present study analyzed the effects of different grazing management methods on species diversity and richness in the steppe rangelands of Saveh, Iran. Data were collected from sixty 2×2 m plots within the areas of three, four-years protected range management projec...

2015
Cástor Guisande Juergen Heine Emilio García-Roselló Luis González-Vilas Antonio Vaamonde Jorge M. Lobo Michael Wink

We herein present FactorsR, an RWizard application which provides tools for the identification of the most likely causal factors significantly correlated with species richness, and for depicting on a map the species richness predicted by a Support Vector Machine (SVM) model. As a demonstration of FactorsR, we used an assessment using a database incorporating all species of terrestrial carnivore...

Journal: :مرتع و آبخیزداری 0
قدرت اله حیدری استادیار دانشکدة منابع طبیعی دانشگاه علوم کشاورزی و منابع طبیعی ساری حمید رضا سعیدی گراغانی دانشجوی دکتری مرتع داری دانشگاه تهران

assessment of diversity and species richness in the understanding of ecosystem functions, protect and preserve genetic resources, evaluation and control of environmental change and the success or failure will help natural resource management programs. arbitrary banning livestock grazing program and one of the most common and perhaps the most degraded pastures and reduced the diversity and speci...

2016
Yong-Hong Liu Jian-Wei Guo Nimaichand Salam Li Li Yong-Guang Zhang Jian Han Osama Abdalla Mohamad Wen-Jun Li

Xinjiang, a region of high salinity and drought, is a host to many arid and semi-arid plants. Many of these plants including Ferula spp. have indigenous pharmaceutical histories. As many of the medicinal properties of plants are in tandem with the associated microorganisms residing within the plant tissues, it is advisable to explore the endophytic potential of such plants. In the present study...

Introduction: One of the ways of restoration and reclamation of damaged rangeland is to use different methods of rain harvesting such as pitting, counter furrowing, flood spreading, small arc basins system and etc., along with the reduction of runoff, it increases the soil moisture content and thus increases vegetation cover. Biodiversity is most commonly used to describe the number of species....

Journal: :Water 2022

Glacier-fed streams are one of the environments most sensitive to global climate change. However, effects freezing–thawing process on benthic macroinvertebrate communities in different habitats glacier-fed unclear. In this paper, we investigated macroinvertebrates riffles and pools a stream Xinjiang, China, during pre-freezing period (November, 2018), freezing (January 2019), thawing (April, 20...

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