نتایج جستجو برای: fish diversity
تعداد نتایج: 287954 فیلتر نتایج به سال:
Coral reefs, the most diverse of marine ecosystems, currently experience unprecedented levels of degradation. Diseases are now recognized as a major cause of mortality in reef-forming corals and are complicit in phase shifts of reef ecosystems to algal-dominated states worldwide. Even so, factors contributing to disease occurrence, spread, and impact remain poorly understood. Ecosystem resilien...
fish biodiversity investigation in urmia basin which is a part of irano-anatolian hot spot aimed to determine the state of fish in this endorheic basin. based on the obtained results, freshwater fish species of the urmia basin comprise 29 species in 25 genera, 7 families, 5 orders and one class. the most diverse order is the cypriniformes with 23 species (79.31%) followed by salmoniformes and p...
The Holocene evolution of eight South African coastal lakes and lagoons is examined and related to changes in fish composition over that period. Historical and current connectivity with riverine and marine environments are the primary determinants of present-day fish assemblages in these systems. A small and remarkably consistent group of relict estuarine species have persisted in these coastal...
There is an increasing need to examine regional patterns of diversity in coral-reef systems since their biodiversity is declining globally. In this sense, additive partitioning might be useful since it quantifies the contribution of alpha and beta to total diversity across different scales. We applied this approach using an unbalanced design across four hierarchical scales (80 sites, 22 subregi...
Determining how ecosystem function and services are related to diversity is necessary for predicting the consequences of diversity loss and for setting goals and priorities for marine conservation. The consequences of biodiversity loss for ecosystem functions and services depend on the level of functional redundancy – the number of species with similar ecological functional traits. Using field ...
In view of the bad convergence performance and low precision of standard artificial fish swarm algorithm in the water quality properties identification, this paper put forward an improved identification model based on adaptive parameters optimization. Firstly, it optimized the immune cloning and selection algorithm (ICSA) in periodic mutation operator and selection operator. Then it introduced ...
Positive correlations between diversity and stability have been reported for a number of ecosystems and are thought to be caused by a stabilizing effect of differential species’ responses to environmental perturbation. Empirical field studies in which investigators tested for diversity–stability relationships are lacking for some taxonomic groups and typically have not included tests of the imp...
Coral reefs are highly complex ecological systems, where multiple processes interact across scales in space and time to create assemblages of exceptionally high biodiversity. Despite the increasing frequency of hierarchically structured sampling programs used in coral-reef science, little progress has been made in quantifying the relative importance of processes operating across multiple scales...
Harike wetland was declared a Ramsar site in 1990. It is located at the confluence of two major rivers of Indus rivers system, the Beas and the Sutlej, but was never explored extensively for its existing fish biodiversity. Earlier only 27 fish species of commercial value were reported from the wetland. Acknowledging its importance for rich diversity fish assemblages in seven different reaches o...
We used local and landscape models to predict fish assemblages in the Great Swamp, NY, a region undergoing rapid development. Fish were surveyed across 17 sites. Fish-species richness, diversity, percent intolerant species, and IBI metrics for fish species richness, benthic insectivores, terete minnows, and dominant species were calculated. Local stream features were characterized and surroundi...
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