نتایج جستجو برای: diversity of vegetation density

تعداد نتایج: 21214870  

2015
Haroun Chenchouni Taha Menasria Souad Neffar Smail Chafaa Lyès Bradai Rachid Chaibi Mohamed Nacer Mekahlia Djamel Bendjoudi Abdelkrim Si Bachir

The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenne...

Journal: :caspian journal of environmental sciences 2009
b. gupta

effect of fire on phyto-sociology of understorey vegetation in chir pine forests of three different silvological characteristics was compared with pure grassland. 15 grasses, 1 sedge, 5 legumes and 21 non-legumes were recorded in the four study sites. floristic composition gradually increased from june to august and then declined slowly by october in all the plots. maximum number of species was...

Introduction: With thirteen critical erosion hubs containing an area of roughly 532 thousand hectares, and 14 regions influenced by wind erosion with an area of 1144311 hectares, the Yazd province ranks fifth among the Iranian provinces in terms of the magnitude of crisis hub, and third in terms of the extent of affected areas. The history of desertification activities in the province dates bac...

2015
Şerban Procheş Félix Forest Sarah Jose Michela De Dominicis Syd Ramdhani Timothy Wiggill

Recent advances in the field of plant community phylogenetics and invasion phylogenetics are mostly based on plot-level data, which do not take into consideration the spatial arrangement of individual plants within the plot. Here we use within-plot plant coordinates to investigate the link between the physical distance separating plants, and their phylogenetic relatedness. We look at two vegeta...

2012
Eric M. Wood Anna M. Pidgeon Volker C. Radeloff Nicholas S. Keuler

a r t i c l e i n f o Keywords: Band 4 Foliage-height diversity Horizontal vegetation structure Image texture Infrared air photo Landsat NDVI Wildlife habitat Ecologists commonly collect data on vegetation structure, which is an important attribute for characterizing habitat. However, measuring vegetation structure across large areas is logistically difficult. Our goal was to evaluate the degre...

2015
Hongyuan Ma Haoyu Yang Zhengwei Liang Mark K. J. Ooi

BACKGROUND Management regimes for vegetation restoration of degraded grasslands can significantly affect the process of ecological succession. However, few studies have focused on variation in the soil seed bank during vegetation restoration under different management regimes, especially in saline-alkaline grassland habitats. Our aim was to provide insights into the ecological effects of grassl...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده علوم 1375

in chapter one we will describe definitions and preliminary results to provide the global context of our own results to be presented in detail in the subsequent chapters in chapter two we consider degree-one maps of the circle and we study their rotation set. our main result in this chapter says that if the map is topologically mixing then its rotation interval is nontrivial (that is, not reduc...

Journal: :journal of rangeland science 2012
soode miarrostami mohammad hasan jouri

overgrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. in order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this effect with exclosure area, and proving of the excluded area effects on plant diversity; two sites of kojour rangeland, mazandran ...

ژورنال: یافته 2012
آزاد بخت, لیلا, اسماعیل زاده, احمد, روحانی, سید محمد حسین ,

Background : Dietary energy density and dietary diversity score (DDS) are two representative factors of dietary quality. In the current study we evaluated these factors in Isfahanian youths. Materials and Methods: This cross-sectional study was conducted on 289 healthy female youths who were randomly selected from students of Isfahan university of medical sciences. A validated semi quantitativ...

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2014
V C Oliveira E A Gonçalves R G Alves

Riparian vegetation along streams in the Atlantic Forest in Brazil contributes to the formation of a highly heterogeneous leaf litter in streambeds. To investigate the structure and composition of the aquatic invertebrate community during the process of leaf decomposition of two plant species present along the banks of the stream studied, 21 plastic mesh bags containing 2.5g (dry weight) of lea...

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