نتایج جستجو برای: species mixture

تعداد نتایج: 634708  

Objective: Ecosystems with mixed species compared to the ones with pure compositions provide a broader range of options in the fields of biodiversity, conservation, protection and restoration. Nearly all forest plantations are established as monocultures, but research has shown that there are potential advantages to be gained by using carefully designed species mixtures in place of monocultures...

Objective: Ecosystems with mixed species compared to the ones with pure compositions provide a broader range of options in the fields of biodiversity, conservation, protection and restoration. Nearly all forest plantations are established as monocultures, but research has shown that there are potential advantages to be gained by using carefully designed species mixtures in place of monocultures...

Journal: :Ecology 2009
Forest I Isbell H Wayne Polley Brian J Wilsey

Development of theory has outpaced experimental tests for most maintenance of diversity mechanisms. Here we demonstrate how data from biodiversity-ecosystem functioning experiments can be used to determine the mechanisms that maintain plant species diversity. We hypothesized that grassland plant diversity is maintained by two classes of mechanisms: (1) equalizing mechanisms, which reduce asymme...

Journal: :محیط زیست طبیعی 0
وحید علی جانی دانشجوی کارشناسی ارشد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران محمود زبیری استاد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران محمدرضا مروی مهاجر استاد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران

quantifying spatial structure is one of the most important components, describing natural ecosystems and their biodiversity. in this study, a set of indices and functions related to spatial structure using 102 established plots with an area of 1000 m2 were presented. to achieve spatial structure of carpinus-fagus type, a set of indices (clark & evans, uniform angle, shannon-wiener, mingling and...

Journal: :transport phenomena in nano and micro scales 2013
b. zahed t. fanaei s. h. ateshi

the growth rate and uniformity of carbon nano tubes (cnts) based on chemical vapor deposition (cvd) technique is investigated by using a numerical model. in this reactor, inlet gas mixture, including xylene as carbon source and mixture of argon and hydrogen as  carrier gas enters into a horizontal cvd reactor at atmospheric pressure. based on the gas phase and surface reactions, released carbon...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1388

based on the latest records of typhlops vermicularis merrem, 1820 from iran, this species is distributed in the northern and southern regions of the country. in this study, new records of typhlops vermicularis are presented and it is shown that distribution range of this species is extended towards the eastern and western iran, and according to the new distribution map, it can be assumed that t...

2002
Chuangmin Liu Lianjun Zhang Craig J. Davis Dale S. Solomon Jeffrey H. Gove

A finite mixture model is used to describe the diameter distributions of mixed-species forest stands. A three-parameter Weibull function is assumed as the component probability density function in the finite mixture model. Four example plots, each with two species, are selected to demonstrate model fitting and comparison. It appears that the finite mixture model is flexible enough to fit irregu...

Journal: :Agriculture and Agricultural Science Procedia 2015

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