Gremios tróficos y modelos de anidamiento de los ensamblajes de aves del Parque Nacional Jardines de la Reina, Cuba
Date
2013-07-06
Authors
Fundora Caballero, Daylon
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad Central "Marta Abreu" de Las Villas
Abstract
En ecología de comunidades naturales, una polémica común es si el ensamble de especies que las conforman, responde a procesos determinísticos o aleatorios. Se han descrito varias reglas de ensamblaje de especies, y entre éstas la hipótesis del subgrupo anidado, que caracteriza a las comunidades en el contexto de biotas fragmentadas. La misma plantea que las especies propias de sitios pobres, constituyen subconjuntos no aleatorios de las especies de sitios con mayor riqueza específica. En el Parque Nacional Jardines de la Reina, al sur de la región central de Cuba, se realizó un estudio para determinar si el anidamiento era una propiedad de la comunidad y de los ensambles de especies por gremios tróficos. Se consideraron tres clasificaciones en gremios tróficos para las comunidades de aves presentes en el área. Se confeccionó una matriz de presencia-ausencia de especies para cada gremio considerado en los sistemas de clasificación. Para calcular el grado de anidamiento se empleó el índice de Anidamiento de relleno superpuesto y decreciente. Este varía entre 0 y 100, con los valores más cercanos a 100 si existe anidamiento. Se emplearon cuatro modelos nulos para evaluar la significación estadística del anidamiento con respecto a los valores observados en las matrices de datos. La mayoría de los ensambles de especies de los gremios tróficos manifestó anidamiento significativo. Solamente cuatro gremios (Carnívoro de orilla con picoteo no superficial, insectívoro aéreo, insectívoro de tronco y follaje con espigueo e insectívoro/frugívoro), no presentaron anidamiento, con valores de probabilidad de entre 0,20 hasta 0,65 con respecto a los modelos nulos. Estos valores para subgrupos anidados se presentarían iguales o menores a 0,01. Los gremios tróficos no anidados presentaron composiciones de especies muy especializadas a determinados recursos tróficos, así como de especies de gran movilidad; posibles factores que explican dichos resultados. Lo anterior demuestra la existencia de una estructura anidada en el área de estudio, dependiente de las agrupaciones de las especies por gremio trófico. Esto, puede servir de elemento de juicio para el manejo, protección y conservación de las ornitocenosis presentes en el área.
Whether the species assemblages are governed by deterministic or stochastic processes still remains as a debatable issue within the ecology of natural communities. A number of assembly rules have been described and among them is the hypothesis of nested subsets which characterizes communities within the context of fragmented biota. This hypothesis states that species inhabiting poor sites are non-random subsets of species in sites with higher species richness. In the Jardines de la Reina National Park, south-central Cuba, we studied if nestedness constitutes a feature of both species assemblages sorted out by trophic guilds and the overall community. Three different criteria were used to classify the bird communities into trophic guilds present in the study area. A presence-absence matrix of species for each guild was built up taking into account the three classification schemes. In order to calculate the degree of nestedness, we used the “nestedness metric based on overlap and decreasing fill” index which varies from 0 to 100, with highest values indicating nestedness. For assessing its statistical significance regarding the observed values in the data matrices, four null models were used. Most species assemblages of trophic guilds showed significant degree of nestedness except for four guilds (non-superficial pecking edge-foraging carnivores, aerial insectivores, trunk-and-foliage gleaning-insectivores and insectivores/frugivores) with probabilities values from 0,20 to 0,65 in relation to the null models. These values for nested subgroups would be equal or lower than 0,1. Unnested trophic guilds were made up by very specialized species compositions exploiting specific food items, as well as by high mobility species; plausible factors explaining these results. This certainly points out to the existence of a nested structure within the study area depending on the species groupings per trophic guild, which in turn, provides further theoretical frameworks for the management and preservation of the avian diversity present in Jardines de la Reina archipelago.
Whether the species assemblages are governed by deterministic or stochastic processes still remains as a debatable issue within the ecology of natural communities. A number of assembly rules have been described and among them is the hypothesis of nested subsets which characterizes communities within the context of fragmented biota. This hypothesis states that species inhabiting poor sites are non-random subsets of species in sites with higher species richness. In the Jardines de la Reina National Park, south-central Cuba, we studied if nestedness constitutes a feature of both species assemblages sorted out by trophic guilds and the overall community. Three different criteria were used to classify the bird communities into trophic guilds present in the study area. A presence-absence matrix of species for each guild was built up taking into account the three classification schemes. In order to calculate the degree of nestedness, we used the “nestedness metric based on overlap and decreasing fill” index which varies from 0 to 100, with highest values indicating nestedness. For assessing its statistical significance regarding the observed values in the data matrices, four null models were used. Most species assemblages of trophic guilds showed significant degree of nestedness except for four guilds (non-superficial pecking edge-foraging carnivores, aerial insectivores, trunk-and-foliage gleaning-insectivores and insectivores/frugivores) with probabilities values from 0,20 to 0,65 in relation to the null models. These values for nested subgroups would be equal or lower than 0,1. Unnested trophic guilds were made up by very specialized species compositions exploiting specific food items, as well as by high mobility species; plausible factors explaining these results. This certainly points out to the existence of a nested structure within the study area depending on the species groupings per trophic guild, which in turn, provides further theoretical frameworks for the management and preservation of the avian diversity present in Jardines de la Reina archipelago.
Description
Keywords
Parque Nacional Jardines de la Reina, Cuba, Aves