نتایج جستجو برای: richness

تعداد نتایج: 20745  

Journal: :بوم شناسی کشاورزی 0
فخرالدین هاشمی شادگان کوروس خوشبخت عبدالمجید مهدوی دامغانی هادی ویسی هومان لیاقتی

biodiversity is an important component in sustainability assessment of agroecosystems. along with increasing or decreasing of biodiversity, ecosystem services in agroecosystems will be varied. agricultural experts take into account different factors which affect agroecosystems variation. in this study, farming systems of two areas including a protected mountainous area and also a plain – hilly ...

Journal: :Neotropical entomology 2010
Soraia Diniz Paulo I Prado Thomas M Lewinsohn

Anthropogenic changes in the landscape result in an environmental mosaic with serious consequences for biodiversity. The aim of the present study was to assess the effects of the anthropogenic changes on Asteraceae richness and abundance, and to evaluate the consequences for the richness of Tephritidae assemblages in five sampling sites, with three sampled habitats in each: cerrado (Brazilian s...

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...

Journal: :محیط زیست طبیعی 0
میترا شریعتی نجف آبادی دانش آموخته کارشناسی ارشد محیط زیست، گروه شیلات و محیط زیست، دانشکده منابع طبیعی، دانشگاه تهران محمد کابلی استادیار، گروه شیلات و محیط زیست، دانشکده منابع طبیعی، دانشگاه تهران صاحبه کریمی دانشجوی کارشناسی ارشد محیط زیست، گروه شیلات و محیط زیست، دانشکده منابع طبیعی، دانشگاه تهران وحید خدایی دانش آموخته کارشناسی محیط زیست، گروه شیلات و محیط زیست، دانشکده منابع طبیعی، دانشگاه تهران سپیده شاکری دانشجوی کارشناسی ارشد مدیریت محیط زیست، گروه مدیریت و برنامه ریزی محیط زیست، دانشکده محیط زیست، دانشگاه تهران سعید محمدی دانش آموخته کارشناسی ارشد رشته علوم محیط زیست، دانشکده محیط زیست و انرژی، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران

hyrcanian forests in northern slope of alborz support high bird richness and abundance same as central of europe. in this study, efficiency of different methods including fixed-width transect, variable-width transect, fixed-radius point count and variable circular plot samplings were compared in order to present the most reliable methods for surveying and monitoring of diurnal forest birds in f...

Journal: :Ecology letters 2008
Susan Harrison Howard Cornell

Despite widespread acknowledgement that local ecological communities are profoundly shaped by regional-scale influences, including evolutionary and biogeographic processes, this perspective has yet to be widely incorporated into ecological research. Drawing on recent research, we propose four steps towards making regional influences a stronger part of research on the richness of local communiti...

الوانی نژاد, سهراب, اسماعیل زاده, امید , ذاکری پاشاکلایی, محسن,

Diversity is one of the most important issues in studies of vegetation ecology. This study was carried out in research forest of Tarbiat Modares University for surveying herbaceous and woody species diversity in relation to topographical factors (altitude, slope and aspect). For this purpose, 48 plots 400 m2 (20×20 m) were established in the region using selective sampling method. Then, the nam...

خلیل‌آبادی, سمیه, سفیانیان, علیرضا, متین‌خواه, سیدحمید, همامی, محمودرضا, کابلی, محمد,

  Determining landscape parameters influencing species richness of habitat patches is one of the most important issues in conservation biology. Many previous studies have investigated the influence of habitat parameters on bird assemblages in forest patches, but studies seeking effects of oasis parameters on bird assemblages are very scarce. Karkas Protected Area is located in semi-arid zone in...

2010
Daniel J. McGlinn Michael W. Palmer

Variation in individual density may explain the unimodal richness-biomass relationship in which species richness peaks at an intermediate level of total biomass. However, it is unclear how individual density is regulated by community thinning (i.e., mortality due to competition with neighbors) as total above-ground biomass increases. We developed a simulation model which demonstrates that the s...

2016
Peter U. Middelfart Lisa A. Kirkendale Nerida G. Wilson Michael Wink

Assessing the marine biodiversity of the tropics can be overwhelming, especially for the Mollusca, one of the largest marine phyla in the sea. With a diversity that can exceed macrofaunal richness in many groups, the micro/meiofaunal component is one of most overlooked biotas in surveys due to the time-consuming nature of collecting, sorting, and identifying this assemblage. We review trends in...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید