نتایج جستجو برای: conserving fish habitat
تعداد نتایج: 162848 فیلتر نتایج به سال:
Introduction Consequences of declines in bumblebee populations Causes of bumblebee declines Reductions in floral resources Loss of nest sites Pesticides Impacts of non-native bees Habitat fragmentation and population structure Why do some bumblebee species remain common? Conserving bumblebees Enhancing bumblebee diversity in farmland The importance of urban areas Conclusions Summary Points Unre...
Knowledge of the effect of habitat type and region on diet and feeding behaviours of a species facilitates a better understanding of factors impacting populations, which contributes to effective conservation management. Using spraint analysis and relative frequency of occurrence data from the literature, we described the dietary patterns of Eurasian otters (Lutra lutra) in 23 study sites within...
The importance of seagrass beds and mangroves as juvenile habitats for coral reef fishes is still debatable. We hypothesised that the configuration of these habitats in the marine landscape in relation to the coral reef would influence accessibility from the reef (both for fishes that use these habitats for shelter or feeding, and their predators). In combination with differences in habitat com...
estimation of river sediment load is one of the most important issues in design of hydraulic structures, investigating water quality, conserving fish habitat, estimating erosion and determining watershed management effects. there are two methods for estimating sediment load: empirical and hydrological methods. existence of numerous empirical methods for estimation of river sediment load and a w...
—The Cape Fear shiner Notropis mekistocholas is an endangered minnow endemic to the Cape Fear River basin of North Carolina; only five populations remain, all of which are declining. Determining the population densities and habitat requirements of the species is critical to its survival and restoration planning. We conducted population surveys (four sites) and instream microhabitat suitability ...
—We used regression quantiles to model potentially limiting relationships between the standing crop of cutthroat trout Oncorhynchus clarki and measures of stream channel morphology. Regression quantile models indicated that variation in fish density was inversely related to the width:depth ratio of streams but not to stream width or depth alone. The spatial and temporal stability of model predi...
Despite their promise for simulating natural complexity, individual-based models (IBMs) are rarely used for ecological research or resource management. Few IBMs have been shown to reproduce realistic patterns of behavior by individual organisms. To test our IBM of stream salmonids and draw conclusions about foraging theory, we analyzed the IBM’s ability to reproduce six patterns of habitat sele...
Instream flow needs (IFN) assessment studies are performed to provide guidelines for stream water management and to assess the impacts of different water projects such as weirs, dams and stream diversions on the available fish habitat. The physical habitat simulation is one of the IFN assessment methods and also a powerful tool in management of river ecosystem that has not become a common metho...
The paddlefish (Polyodon spathula) is a primitive fish that is found in several large rivers of the Mississippi River drainage. The status of paddlefish populations in these large rivers is debatable due to several factors including habitat loss, contaminants and commercial fishing (Sparrowe 1986; Gundersen and Pearson 1992). The roe of female paddlefish is used to make domestic caviar and comm...
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