Abstract

ARANGUREN-RIANO, NELSON JAVIER  and  MONROY-GONZALE, JOSÉ DANIEL. Zooplankton Responses in a Tropical System (La Chapa Reservoir, Colombia) with Environmental Stress. Acta biol.Colomb. [online]. 2014, vol.19, n.2, pp.281-290. ISSN 0120-548X.  https://doi.org/10.15446/abc.v19n2.38095.

Processes of environmental transformation that currently occur in the climatic change context generate changes in ecosystems and biological communities. ?how populations respond to these stressors? ?what effects could occur on taxonomic and ecological diversity? The taxonomic composition and structure of the zooplankton was analyzed with relationship to environmental changes in a tropical water reservoir located at 6° 02' 18" N and 73° 29' 16" W. During four months, samples were taken weekly covering stations of low, medium, and high precipitation. A high degree of temporal variability was established, it associated with a short hydraulic retention time estimated at eight days. Nine species of zooplankton were collected, of which Keratella tropica tropica and Thermocyclops decipiens were the two most abundant and constant species. Found values of H' diversity and S richness were considered low, corresponding to a little mature community associated with a fluctuating physical environment and supported by high variation coefficients of electrical conductivity and Sechhi disk transparency. Drastic variations on the system volume in short time lapses generate important changes in the physical expression of system with a direct effect on composition and structure of the zooplankton. In general, the response model of the zooplankton in the reservoir according to the statement by the intermediate disturbance hypothesis.

Keywords : environmental stress; intermediate disturbance hypothesis; La Chapa reservoir; zooplankton.

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