نتایج جستجو برای: abundance of tolerant taxa eg chironomidae
تعداد نتایج: 21174288 فیلتر نتایج به سال:
for study of systematic and palaeoecology of mid-cretaceous oysters, the basab section, with 380 m thickness, west of kuhbanan, northwest of kerman, was measured and sampled. the section comprises a high diverse fauna (macro and microfossils), such as echinoids, bivalves, oysters, brachiopods, gastropods, corals, ammonites, foraminifers and ostracods. the fossils indicate late aptian- early cen...
خانواده chironomidae (diptera: insecta) با داشتن فراوان ترین و متنوع ترین حشرات گسترش جهانی دارد و در اغلب اکوسیستم های آب شیرین از جمله آب های داخلی ایران یافت می شود. با وجود این، پژوهش های معدودی برای شناسایی این گروه در ایران انجام شده و دانش موجود از گوناگونی فون و پراکندگی آنها در کشور بسیار ناچیز است. برای شناخت لاروهای خانواده chironomidae در رودخانه ماربر، استان اصفهان، نمونه برداری ها...
Searching for indicator taxa representative of diverse assemblages, such as arthropods, is an important objective of many conservation studies. We evaluated the impacts of a wide gradient of disturbance in Gabon on a range of arthropod assemblages representing different feeding guilds. We examined 4 x 10(5) arthropod individuals from which 21 focal taxa were separated into 1534 morphospecies. R...
Larvae of over 50 families of nearshore fishes were taken in oceanic waters about 13 km offshore of the leeward (southwest) coast of Oahu, Hawaii during 1977-78, The five most frequently taken families (Labridae, Parapercidae, Serranidae, Gobiidae, and Carangidae) made up over 50 % of the total nearshore larvae. Most other families were taken very infrequently. Comparison of catch data from thr...
Surveys of the benthic macroinvertebrate community were conducted in the main basin of Lake Huron in 2000 and 2003, and in Georgian Bay and North Channel in 2002. Results were compared to surveys conducted in the 1960s and early 1970s. Although data of earlier surveys were inconsistent, our best estimates suggest that total density of the four major benthic taxa (Diporeia spp., Oligochaeta, Sph...
The absolute diversity of prokaryotes is widely held to be unknown and unknowable at any scale in any environment. However, it is not necessary to count every species in a community to estimate the number of different taxa therein. It is sufficient to estimate the area under the species abundance curve for that environment. Log-normal species abundance curves are thought to characterize communi...
Soil and litter arthropods are important in many forest ecosystem processes where they help to regulate nutrient dynamics and soil quality, and are useful bioindicators of ecosystem condition and change. This study was initiated in response to concerns about possible decline in site productivity due to intensive forestry practices. We investigated the effects of tree harvesting and site prepara...
The importance of interannual variation in deep-sea abundances is now becoming recognized. There is, however, relatively little known about what processes dominate the observed fluctuations. The abundance and size distribution of the megabenthos have been examined here using a towed camera system at a deep-sea station in the northeast Pacific (Station M) from 1989 to 2004. This 16-year study in...
Climate change is increasing the frequency of extreme fires. In 2019–2020, fires burned 97 000 km2 native vegetation in south-eastern Australia, affecting many areas rainforest, which has historically less frequently. One year post-fires, we surveyed litter macroinvertebrates 52 temperate rainforest sites. Sites had experienced levels fire severity (unburnt, medium and high severity). We asked ...
abstract: in this study, al 2 o 3 /eg and tio 2 /eg nanofluids as coolants have been used in the double-tube heat exchanger. the hot solvent inlet heat exchanger must be cooled down with a specified amount. we can use nanofluids as coolants in the heat exchanger for optimization of the heat transfer area. therefore, the efficacy of nanofluids as coolants is verified. furthermore, flow rate of c...
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