نتایج جستجو برای: trophic indices
تعداد نتایج: 97826 فیلتر نتایج به سال:
The effect of anthropic alterations such as drain discharge on a fish community was studied in the Ribeirão Claro River, municipality of Rio Claro, State of São Paulo, southeastern Brazil. Samples were made monthly in three different points along the river (headwaters, mid course, and confluence) between December, 2003 and March, 2004, which is the reproductive period for the majority of the sp...
Aquatic ecosystem biomonitoring tools are largely lacking for many developing countries, resulting in adoption of tools developed from other countries/regions. In many instances, however, the applicability of adopted tools to the new system has not been explicitly evaluated. The objective of this study was to test the applicability of foreign diatom-based water quality assessment indices to urb...
Nematode communities were monitored for three years in a citrus soil ecosystem in Central Florida under various agricultural regimes comparing standard vs. reduced-input practices. Differences in agricultural regimes consisted of two fertilization levels, two irrigation levels, and two types of ground cover under the tree (herbicide vs. mulch). While some nematodes were affected sporadically by...
Various definitions and indices have been proposed in the literature to identify keystone species. In this study, we intended to make the concept of keystone species operational for marine biodiversity conservation. We used an exclusive definition of keystone species, based on the original concept of keystone predator, and derived a new functional index of keystoneness (KS) from an ecosystem-mo...
The distribution of biomass among trophic levels provides a theoretical basis for understanding energy flow and the hierarchical structure of animal communities. In the absence of energy subsidies [1], bottom-heavy trophic pyramids are expected to predominate, based on energy transfer efficiency [2] and empirical evidence from multiple ecosystems [3]. However, the predicted pyramid of biomass d...
In the Anthropocene, man has imposed his activities above natural processes of ecosystems. Rivers have undergone major changes associated with urban centers, so monitoring them is important to determine their status and suitability provide environmental services. Studies applying community ecology approach, such as energy flow in aquatic macroinvertebrate assemblages, may be appropriate functio...
Abstract This work concerns the inventory of invertebrates in apple tree plot Dorset golden variety Tizi-Ouzou area by using four methods trapping (Barber traps, coloured sweep net and butterflies net) during study period from July 2015 until June 2016. allowed us to collect 214 species belonging 96 families, 18 orders five classes invertebrates. Ecological indices make it possible account for ...
The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females ...
The present article gives an overview on the leading concepts and modelling approaches for marine ecosystems' research including (1) The trophodynamic theory of pelagic ecosystems, (2) Compartment/network models, (3) Mesocosm experiments and (4) Individual based modelling approaches and virtual ecosystems (VE). The main research questions addressed, as well as the potential and limits of each a...
105 inTroducTion Civilian Tactical Emergency Medical Support (TEMS) has a long history in the United States. Enormous progress has been made during the past ten years in developing professional and operational standards within the field. However, to date, there still exists no standard of care within TEMS specifically, and more broadly for high threat pre-hospital trauma care. Current civilian ...
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