نتایج جستجو برای: diversity index
تعداد نتایج: 577656 فیلتر نتایج به سال:
microcerotermes diversus (silvestri) (isoptera: termitidae), an important wood pest in ahwaz (khuzestan, iran), causes serious economic damage to cellulosic products in buildings. to investigate the genetic diversity of this pest, 13 populations from different areas of khuzestan province as well as two samples from khark island and bandar abbas were collected. following dna extraction a fragmen...
silvicultural operation need to notice the plant species diversity in forest. to this study gomarlang district in marivan region, northern zagros forest was selected. selected 100 ha area because have similar physiography condition (north aspect and 1650 to 1800 m s.a.l. in study area 100 micro plots of 5m by 5 m (25 m2) including the species and the numbers of this species randomized-systemati...
forest roads are directions in natural habitats that used to transport wood products, secondary forest products and recreation. constructing forest roads causes trees clearing with specified width thus lead to direct or indirect changes in forest ecosystems and forest environment. this study aims to assess the changes of diversity and richness indices in main and secondary forest roads in a par...
Hubbell's neutral model has become a major paradigm in ecology. Whereas the steady-state structure is well understood, results about the dynamical aspects of the model are scarce. Here we derive dynamical equations for the Simpson diversity index. Both mean and variance of the diversity are proven to satisfy stable linear system dynamics. We show that in the stationary limit we indeed recover p...
Understanding the plant species diversity could be used as an importantindicator applied for the natural areas management. The aim of this study was toinvestigate the relationships between soil characterizes with distribution and diversity ofplant in vegetation types in Karvan district (located in west of Isfahan province). For thispurpose, three vegetation types were selected as follows: Scari...
fish species diversity, distribution and abundance were studied in the sardabrud and chalus rivers, in the southern caspian sea basin, during 1992 and 1993 in five and four stations respectively, by monthly collections using electrofishing device. in total, 3200 fish specimens, including 15 species in sardabrud river and 12 species in chalus river, were investigated. the fish comprised of 13 ge...
in this study an attempt has been made to empirically examine the relationship between biodiversity and economic growth using indicators of species diversity and income per capita as proxies for biodiversity and economic growth, respectively.also the effects of agricultural value added as a percentage of gdp, trade freedom index, exchange rate, population, percantage of land developed for agric...
This study was performed in second half of year 2009.For bird counting , monthly from Septamber until March 2009. Total counted birds in Maroon lake were (971). Maximum number of counted birds was in February (191) and minimum of counted was in Septamber (95). Total counted birds in Jaizan were (385. Maximum number of the counted bird was in February (84) and minimum of counted (52) was in Ja...
The gobies are non-commercial fishes in the Iranian waters of the Caspian Sea for which population dynamics and stock status are poorly known. In this survey, we tried to define species diversity and catch per unit effort (CPUE) of Gobiidae by using beach seine nets in Salmanshahr, the southern Caspian Sea. From March 2011 to April 2012, 224 specimens representing 4 gobiid species, belonging to...
The gobies are non-commercial fishes in the Iranian waters of the Caspian Sea for which population dynamics and stock status are poorly known. In this survey, we tried to define species diversity and catch per unit effort (CPUE) of Gobiidae by using beach seine nets in Salmanshahr, the southern Caspian Sea. From March 2011 to April 2012, 224 specimens representing 4 gobiid species, belonging to...
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