INVESTIGADORES
SOSNOVSKY Alejandro
artículos
Título:
Top predator fish assemblages in Northern Patagonia, Argentina. What factors regulate their patterns of distribution and abundance?
Autor/es:
FERNÁNDEZ, MARÍA VALERIA; LALLEMENT, MAILÉN; RECHENCQ, MAGALÍ; VIGLIANO, PABLO H.; SOSNOVSKY, ALEJANDRO; MACCHI, PATRICIO J.
Revista:
AUSTRAL ECOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2018 vol. 43 p. 651 - 662
ISSN:
1442-9985
Resumen:
According to assemblage theory, three factors regulate fish biogeography: restriction of dispersion,environmental restrictions and biotic interactions. The first two factors act on a regional scale and delimit thearea of action of the third, which operates on a local scale. Salmonid introductions began in Patagonia in 1904,and this has led to a restructuring of trophic webs and an increase in the number of top predators. This situationallowed us to evaluate, in a natural setting, how communities are formed on different geographic scales. Westudied two large basins in Patagonia, situated close to each other but with different assemblages of top predatoryfish. We hypothesized that differences in the structuring of the top predator assemblages between and withinthe basins are due to 1) environmental factors and dispersion processes facilitated by connectivity on a regionalscale; and 2) biotic interaction (internal dynamics) between native perch and salmonids, the former acting as amodulator of the top predator assemblages on a local scale. To test these hypotheses, we analysed the top predatorassemblages of 16 lakes and one reservoir, as well as their environmental characteristics. We performed acluster analysis and related the resulting assembly groups to environmental factors by means of a tree model. Wealso analysed fish diets, using a similarities test to study biotic interactions. On regional and local scales, waterbasin, degree of connectivity, area, temperature and Zoogeographic integrity coefficient (ZIC) were importantfactors in the structuring of top predator assemblages. On a local scale, creole perch modulates the salmonidpopulations through feeding and the consequent distribution of resources. Our work showed that the structureof top predator assemblages was determined by a combination of local and regional factors acting in synergy, aspostulated by the assemblage theory.