Community Organization in Fishes as Indicated by Morphological Features

Abstract

This study uses morphological data relating to many aspects of the niche to study community organization in assemblages of stream fishes from three separate drainages. Mean values for all morphological features were compared statistically for coexisting species pairs, and those features which had significantly different means were assumed to indicate ecological differentiation that exists between the species under consideration. Average niche overlap as defined by the percentage of morphological features not differing significantly between species pairs was constant for these assemblages regardless of a nearly twofold difference in number of species present. Similarly, the average Euclidean distance between the centers of morphologically defined niches for all sympatric common species was approximately the same for all three assemblages. Moreover the distribution of Euclidean distances between species was the same in all three drainages and different than a distribution that would result from a random division of resources. Together, these results indicate that consistent patterns do exist in the organization of these stream communities, and that the species currently living together are not a random assortment of species and do not randomly divide their resources. The presence of higher numbers of species in a community seems not to be accompanied by increased packing of the niches, but rather by an occupation of more total niche space by the community as a whole.

Alimentação E Distribuição Espacial De Algumas Espécies De Peixes Do Igarapé Do Candirú, Amazonas, Brasil

“…Este fato pode ser devido à grande mobilidade dessas espécies, o que permite que elas procurem alimento em toda coluna d'agua. Esta relação foi também mencionada por outros autores (ZARET & RAND, 071;SHOENER, 1974;GORMAN & KARR, 1978;GATZ, 1979;PAINE et. ai, 1982;WERNER, 1984;LOWE-McCONNELL, 1987).…”

“…SHOENER (1974) mencionou que os padrões morfológicos das espécies poderiam ser utilizados para avaliar as diferenças no uso de recurso entre elas. GATZ (1979) também postulou que a utilização de recursos estava relacionada com o fenotipo das espécies e que os peixes se especializavam em seus hábitos de acordo com suas adaptações morfológicas.…”

Cost of morphological specialization: feeding performance of the two morphs in the trophically polymorphic cichlid fish, Cichlasoma citrinellum

“…Keast and Webb 1966;Gatz 1979;van Oijen 1982;Hoogerhoud et al 1983;Barel 1983;Wainwright 1987Wainwright , 1988. Resource partitioning in fishes is believed to be due to functional morphological constraints on prey choice (Werner 1977;Liem 1984;Wainwright 1988).…”

Aspects structurels et fonctionnels de la biodiversité des peuplements de poissons

“…Functional ecological units might include ecomorphology, life-history stratégies, and trophic guilds. Examination of ecomorphological variation has improved knowledge of the structure and function of fish populations and assemblages (GATZ, 1979 ;KEAST & WEBB, 1966 ;MEYER, 1990 ;WINEMILLER, 1991). Comparisons of life-history attributes permit not only the ordination of ecological syndromes, but aiso allow détermination of demography and responses of populations to environmental variation (BALON, 1975 ;VAN WINKLE et al, 1993 ;WINEMILLER & ROSE, 1992).…”

“…Functional ecological units might include ecomorphology, life-history stratégies, and trophic guilds. Examination of ecomorphological variation has improved knowledge of the structure and function of fish populations and assemblages (GATZ, 1979 ;KEAST & WEBB, 1966 ;MEYER, 1990 ;WINEMILLER, 1991 (BALON, 1975 ; VAN WINKLE et al, 1993 ;WINEMILLER & ROSE, 1992). ObviousIy, ail organisms must obtain food and avoid becoming the food of another, in order to persist and reproduce.…”