the population density and spatial distribution pattern of empoasca decipiens paoli were etermined in tehran area, iran, during 2004-2005 on four species of common bean phaseolus vulgaris (l.) var. talash, lima bean p. lunatus (l.) savi ex hassk. var. sadaf, rice bean p. calcaratus roxb. var. goli and cowpea vigna sinensis (l.) var. parastoo. the higher and lower mean population densities of e....

population density and spatial distribution of thrips tabaci lindeman on seven soybean varieties (williams, tellar, sahar, dpx, l17, sari and zane) and one genotype (ks3494) were studied in tehran region, during 2007. the highest population density of the thrips per leaf was recorded on dpx and on ks3494 (0.810.05 and 0.800.05, respectively). the lowest population density was observed on l17 ...

the population densities and spatial distribution patterns of zetzellia pourmirzai khanjani and ueckermann and its preys cenopalpus irani dosse and bryobia rubrioculus (scheuten) were studied in a sprayed orchard in kermanshah, a western province of iran, from 31 may till 7 november, 2007. the interaction (density dependence) between the plant feeding mites and their predator was determined as ...

iran is a large country with a total area of 1,645,000 square kilometers. the country’s population is estimated at about 31 millions. there is an uneven distribution of the population, varying from 2 to 50 per square kilometer. sixty per cent of the total population (18 millions) is living in nearly 66,000 small and large village’s scattered throughout the country. a total of 10,000 physicians ...

population management of exploited species requires information on absolute density and abundance through reliable survey methods. the baseline information is further needed for population dynamics studies and determination of conservation status. the current population size of pheasant is totally unknown, because there is no official attempt to estimate population size in previous years. in th...

1. Small mammal population fluctuations, cyclic or not, have been an ecological puzzle and a source of heated debate among ecologists. Identifying the demographic parameters that covary closely with density changes can help elucidate the underlying causes of population fluctuations, but few studies have reported rigorous estimates of these parameters. 2. We applied capture–mark–recapture analys...

Social behaviour was proposed as a density-dependent intrinsic mechanism that could regulate an animal population by affecting reproduction and dispersal. Populations of the polygynous yellow-bellied marmot (Marmota flaviventris) fluctuate widely from year to year primarily driven by the number of weaned young. The temporal variation in projected population growth rate was driven mainly by chan...

We use panel data from Germany to analyze the effect of population density on urban air pollution (nitrogen oxides, particulate matter, ozone, and an aggregate index for bad quality [AQI]). To address unobserved heterogeneity omitted variables, we present long difference/fixed effects estimates instrumental variables estimates, using historical soil as instruments. Using our preferred find that...