نتایج جستجو برای: evenness

تعداد نتایج: 1999  

Journal: :شیلات 0
سپیده سلیمانی پی کارشناس ارشد زیست شناسی دریا، دانشگاه علوم و فنون دریایی خرمشهر نسرین سخایی استادیار گروه زیست شناسی دریا، دانشکدة علوم دریایی و اقیانوسی، دانشگاه علوم و فنون دریایی خرمشهر سیمین دهقان مدیسه استادیار پژوهشکدة آبزی پروری جنوب کشور احمد سواری استاد گروه زیست شناسی دریا، دانشکدة علوم دریایی و اقیانوسی، دانشگاه علوم و فنون دریایی خرمشهر محمدعلی سالاری استادیار گروه زیست شناسی دریا، دانشکدة علوم دریایی و اقیانوسی، دانشگاه علوم و فنون دریایی خرمشهر

the aim of this investigation was to study the planktonic shrimp-like communities density and diversity in artificial reefs of khuzestan coasts, bahrakan waters (the persian gulf). sampling was conducted for one year from may 2011 to april 2012, monthly. zooplankton were collected with plankton tows using 300 μm mesh net. totally, two superfamily, penaeoidea, sergestoidea and one suborder carid...

Journal: :آب و خاک 0
شایسته غلامی سید محسن حسینی جهانگرد محمدی عبدالرسول سلمان ماهینی

abstract information about the spatial patterns of soil biodiversity is limited though required, e.g. for understanding effects of biodiversity on ecosystem processes. this study was conducted to determine whether soil macrofauna biodiversity parameters display spatial patterns in the riparian forest landscape of karkhe. soil macrofauna were sampled using 200 sampling point along parallel trans...

Journal: :بوم شناسی کشاورزی 0
روح اله مرادی مسعود سامی

sustainability of productions in agricultural ecosystems depends on conservation and amplification of biodiversity. this study was conducted to determine the planting area, species richness, species evenness and biodiversity of different agronomical, horticultural and livestock productions in kerman province. for this purpose, information about planting area of agronomical and horticultural pla...

Journal: :بوم شناسی کشاورزی 0
علیرضا باقری رضا قربانی محمد بنایان اول اورس شافنر

considering the importance of biodiversity conservation and protection assessment activities, the present filed study was conducted with aim to compare vegetation diversity of two areas with different levels of protection including ghorkhod protected area with seasonal grazing and golestan national park without grazing, during spring and summer of 2011. four replications were selected in each a...

2014
Rodrigo S. Rios Cristian Salgado-Luarte Ernesto Gianoli

The climbing habit is an evolutionary key innovation in plants because it is associated with enhanced clade diversification. We tested whether patterns of species divergence and variation of three ecophysiological traits that are fundamental for plant adaptation to light environments (maximum photosynthetic rate [A(max)], dark respiration rate [R(d)], and specific leaf area [SLA]) are consisten...

2007
Edward Byrd Davis Nicholas D. Pyenson

Understanding diversity through time in the fossil record has primarily relied on the raw count of species within a given time interval, or species richness. These estimates are often derived from published fossil data, and standardized for sample size or geographic area. However, most methods that standardize richness by sample size are sensitive to changes in evenness, which introduces a pote...

Journal: :Ecological applications : a publication of the Ecological Society of America 2012
Aaron L Alford Eric C Hellgren Ryan Limb David M Engle

Woody plant encroachment is a worldwide phenomenon in grassland and savanna systems whose consequence is often the development of an alternate woodland state. Theoretically, an alternate state may be associated with changes in system state variables (e.g., species composition) or abiotic parameter shifts (e.g., nutrient availability). When state-variable changes are cumulative, such as in woody...

2015
Marcia C. de Oliveira Otto Nikhil S. Padhye Alain G. Bertoni David R. Jacobs Dariush Mozaffarian Manuel Portero-Otin

Diet guidelines recommend increasing dietary diversity. Yet, metrics for dietary diversity have neither been well-defined nor evaluated for impact on metabolic health. Also, whether diversity has effects independent of diet quality is unknown. We characterized and evaluated associations of diet diversity and quality with abdominal obesity and type II diabetes (T2D) in the Multi-Ethnic Study of ...

2017
Pengtao Xie Aarti Singh Eric P. Xing

Latent space models (LSMs) provide a principled and effective way to extract hidden patterns from observed data. To cope with two challenges in LSMs: (1) how to capture infrequent patterns when pattern frequency is imbalanced and (2) how to reduce model size without sacrificing their expressiveness, several studies have been proposed to “diversify” LSMs, which design regularizers to encourage t...

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