نتایج جستجو برای: species abundance distribution
تعداد نتایج: 1161462 فیلتر نتایج به سال:
mnemiopsis leidyi population activities first were recorded during the coastal observations in 2001 in which its population considerably increased afterward and now sustained the southern caspian sea. maximum summer-autumn m. leidyi abundance was recorded in euphotic layer in 2002 (851±85 ind.m-3) and maximum biomass was in 2001 with 48.1±14.4 g.m-3) while minimum were in aphotic layer. in year...
Ecologists seek to understand patterns of distribution and abundance of species. Studies of distribution often use occurrence data to build models of the environmental niche of a species. Environmental suitability (ES) derived from such models may be used to predict the potential distributions of species. The ability of such models to predict spatial patterns in abundance is unknown; we argue t...
we quantified the distribution, abundance and assemblage structure of macrofauna at 22 stations in gorgan bay, seasonally in 2012-2013. also, depth, temperature, salinity, do, tom and sediment particle size were measured in each station. the highest concentration of tom was measured near the western littoral zone (10.22) while the mouth part and north-eastern area was characterized by the lowes...
1. Modelling species abundance patterns, i.e. the distribution of relative abundance among species within the same community, has become a common framework in community ecology. To describe species abundance patterns several statistical models have been proposed, e.g. the log-normal distribution, but these do not provide an ecological explanation of the underlying processes. 2. Tokeshi introduc...
Extended Abstract Background and objectives: In order to further protect rangeland ecosystems, range suitability in this regard should be investigated before the utilization of medicinal and industrial plants. Plant composition and production and slope of the slope are among the components that determine the suitability of rangeland for the use of medicinal plants. For this purpose, in four ...
Presence-absence and abundance of each fish species in a river habitat depends on several factors and they prefer a specific range of each habitat factor. The present study was carried out to investigate habitat suitability index of Capoeta capoeta and the effect of habitat factors on its distribution and abundance in Roodbabol branch of the River Babolrood (Mazandaran Province). To do, fish sa...
Can species shift their distributions fast enough to track changes in climate? We used abundance data from the 1950s and the 2000s in Wisconsin to measure shifts in the distribution and abundance of 78 forest-understory plant species over the last half-century and compare these shifts to changes in climate. We estimated temporal shifts in the geographic distribution of each species using vector...
Among the biodiversity of soil microorganisms, bacteria have the basic role in soil functions. In order to determine the diversity and abundance of soil bacteria in arid regions, and also to study the effect of agricultural practices on them, a study was conducted in winter wheat fields on Shirvan, Mashhad and Gonabad. In each region, high and low input fields of winter wheat and a natural syst...
phytoplankton communities play a significant role in the oceanic biological pump by forming the base of the trophic structure. increase in nutrients loading affects spatial and temporal distribution of phytoplankton. this study examined the phytoplankton community structure and ecological indices in relation to nutrients dynamics in both estuarine and oceanic areas of ramisi-vanga systems along...
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