نتایج جستجو برای: ephemeroptera
تعداد نتایج: 1009 فیلتر نتایج به سال:
رژیم غذایی و فراوانی ماهی قزل آلای رنگین کمان (oncorhynchus mykiss)، به منزلة گونه ای غیربومی، در رودخانة مادرسو پارک ملی گلستان بررسی شد. در مجموع، 144 نمونه از 2 ایستگاه با طول متوسط 190 میلی متر و وزن متوسط 80 گرم بررسی شدند. با بررسی روی کل ماهیان صیدشده، مشخص شد که، بر اساس نمایة ایولو (ivelev)، در اغلب ماه های سال ephemeroptera (زود میران) مادة غذایی انتخابی بوده همچنین، تقریباً در اکثر ما...
Biological assessment of river Haji Abad (Hormuzgan province) Using Macrobenthic Community Structure
This study aimed to investigate the population structure of benthic communities in Haji Abad River, West of Hormuzgan province. The study was conducted from October 91 till September 92. The three sites were determined based on regional topography and large benthic fauna. Sampling was performed monthly using a 500 micron Surber sampler with three replicates at each station. Samples were fixed i...
High force coefficients, similar to those observed for revolving model hawkmoth wings in the accompanying paper (for which steady leading-edge vortices are directly observed), are apparent for revolving model (mayfly, bumblebee and quail) and real (quail) animal wings ranging in Reynolds number (Re) from 1100 to 26000. Results for bumblebee and hawkmoth wings agree with those published previous...
After a 40-year absence caused by pollution and eutrophication, burrowing mayflies (Hexagenia spp.) recolonized western Lake Erie in the mid 1990s as water quality improved. Mayflies are an important food resource for the economically valuable yellow perch fishery and are considered to be major indicator species of the ecological condition of the lake. Since their reappearance, however, mayfly ...
A new species of the genus Caenis Stephens is described based on the male imago, female imago and egg stages from the state of Rio Grande do Sul, Brazil. The male imago of Caenis gaucha sp. nov. is diagnosed as follows: body length of male 2.0-2.5 mm; base of antennal flagellum not dilated; forceps apically rounded, not fused to lateral margins of styliger plate; styliger plate short with poste...
A Multimetric Benthic Macroinvertebrate Index for the Assessment of Stream Biotic Integrity in Korea
At a time when anthropogenic activities are increasingly disturbing the overall ecological integrity of freshwater ecosystems, monitoring of biological communities is central to assessing the health and function of streams. This study aimed to use a large nation-wide database to develop a multimetric index (the Korean Benthic macroinvertebrate Index of Biological Integrity—KB-IBI) applica...
Five lotic systems of Serra do Cipó, south-east Brazil, were investigated in order to assess the existing diversity of benthic macroinvertebrates, habitats-microhabitats, and the available trophic resources. For each river it was analysed the communities of benthic macroinvertebrates and the composition of some taxonomic groups (Plecoptera, Ephemeroptera, Trichoptera and Diptera Chironomidae): ...
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