Spider diversity: is there a decline with increasing shade in coffee plantations? / Miguel Ángel Pinkus Rendón

Tesis Maestría en Ciencias en Recursos Naturales y Desarrollo Rural El Colegio de la Frontera Sur 2000

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In this study wc test the hypothesis that systems with more shade have higlier spider diversity, by comparing a raintbrest area (high shade) and two coffee systems Irlanda (intermediate shade) and Hamburgo (low shade). Spiders were sampled biweekly during three months of dry season and again for three months of the rainy season in 2000; spider numbers were analyzed for alpha diversity using Shannon and Simpson indices, Cody beta diversity, cluster analyses and correspondence analyses. A total of 2261 individuals were sampled, representing 20 families, 56 genera, 30 species and 68 morphospecies. Highest total Shannon diversity was for Hamburgo and Reserva during the dry and rainy season respectively. When compared by season, spider diversity differed significantly only in Irlanda. Total dominance was highest in Irlanda and Hamburgo during dry and rainy season respectively. Species overlap between the three sites (by the Cody index) was consistently highest between the two coffee farms, whereas Hamburgo shared the fewer species with the forest. Cluster analysis showed changes in abundance hierarchy of species among sites and between seasons. Correspondence analyses show that sites were ordered in its first axis in agreement with the shade gradient in both seasons. Our results, in terms of alfa diversity comparisons did not support the proposed hypothesis. In contrast, beta diversity showed that species composition is influenced by shade and between seasons, in support of this hypothesis. eng

Entomología Tropical