Abstract

TEIXEIRA ROTH, Vanessa  and  SANCHEZ INFANTAS, Edgar. Population patterns of the main herbaceous species at Lachay National Reserve. Ecol. apl. [online]. 2006, vol.5, n.1-2, pp.23-27. ISSN 1726-2216.

Taylor’s power has its bases in the relationship between the average density of a population and its space-temporary variation. In other words it is an empirical relationship between the variance and average of abundance estimations. This is described by the potential ecuation S² = a mb, where S² and m represent the variance and the average, respectively, whereas a and b are parameters to be estimated statistically. The Law of Taylor allows to quantify the degree of aggregation by means of the slope of the model indicating if population patterns are uniform, random or aggregate. Readfern and Pimm (1988) replaced the variance by the variability coefficient, and McArdle (1990) used it to generate a new equation of the Taylor´s Law. The present study was conducted at Lachay National Reserve from February 1998 to July 1999 during which a constant evaluation of the space-temporary variations of the population patterns of the herbaceous community of this ecosystem was made. With this research we determined the main population patterns of the determining species of the herbaceous community of Lachay, as well as their space-temporary variations in a disturbing event such as "El Niño" (1997-1998). As a result we appreciated the population pattern of 16 plant species of the herbaceous community of Lachay: 5 species had a "fixed or moving hotspots" pattern, 5 species had a "refuge" pattern and 3 species had a "hotspots" pattern. These patterns are influenced by meteorological and physical conditions of the atmosphere, such as moisture, precipitation and solar radiation.

Keywords : "El Niño" event; space-temporary variation; Taylor Power Lay and hotsposts.

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