نتایج جستجو برای: ecological indices
تعداد نتایج: 181372 فیلتر نتایج به سال:
BACKGROUND In aggregate studies, ecological indices are used to study the influence of socioeconomic status on health. Their main limitation is ecological bias. This study assesses the misclassification of individual socioeconomic status in seven ecological indices. METHODS Individual socioeconomic data for a random sample of 10,000 persons came from periodic health examinations conducted in ...
Whereas the El Niño Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field o...
This study evaluated the relationship between the indices known as the Reef Health Index (RHI) and two-dimensional Coral Health Index (2D-CHI) and different representative metrics of biological, ecological and functional diversity of fish and corals in 101 reef sites located across seven zones in the western Caribbean Sea. Species richness and average taxonomic distinctness were used to asses b...
The composition of nematode communities (plant-parasitic and free-living) may be used as bioindicators of soil health or condition because composition correlates well with nitrogen cycling and decomposition, two critical ecological processes in soil. Maturity and trophic diversity indices withstand statistical rigor better than do abundances, proportions, or ratios of trophic groups. Maturity i...
Background and Objectives: Implementation of industrial development programs, without considering environmental considerations has caused continuous entrance of pollutants to air. Therefore, the purpose of this study was assessing the ecological risk of some heavy metals in the dust of a number of non-metallic industries and determining the best indices in pollution assessment of Ardakan area. ...
The Improved Generalized Diversity Index (IGDI) has been proposed as a tool that can be used to identify areas that have high conservation value and measure the ecological condition of an area. IGDI is based on the species relative abundances. This paper is concerned with particular attention is given to comparisons involving the MacArthur model of species abundances. The properties and perform...
This study was conducted to evaluate the effect of copper extraction on the structure and function of rangelands ecosystem around the mine area in Dareh Zereshk, Yazd province, Iran. Three study sites were considered at the specified intervals of the mine (0-200, 200-500 and 500-1000m). This research was conducted from 2012 to 2013. In each location, three linear transects with a length of 50 m...
Indices summarizing community structure are used to evaluate fundamental community ecology, species interaction, biogeographical factors, and environmental stress. Some of these indices are insensitive to gross community changes induced by contaminants of pollution. Diversity indices and similarity indices are reviewed considering their ecological application, both theoretical and practical. Fo...
The global decline in estuarine and coastal ecosystems is affecting critical ecosystem services. The spatial agglomeration of population, industries and resources has led to the emergence of regionally-specific ecological problems. Therefore, identifying “ecological red lines”, based on specific natural and environmental features, could help to differentiate the economic development and ecologi...
Background and Objective: Heavy metals contaminations are readily bioaccumulated in aquatic systems and lead to increased concentrations in food chains, posing a serious threat to human health, water-related organisms and aquatic ecosystems. The purpose of the present study was to determine the concentration of heavy metals in surface sediments of CheshmehKile River, to evaluate environmental a...
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