PARENT SESSION
Tuesday, August 8, 5:00-6:30 pm
Poster Session 8 - Aquatic ecology
Exhibit Hall, Ballroom Level, Cook Convention Center
Scale effect on available complexity and influence of complexity as a fractal dimension on invertebrate richness in aquatic plants.
Dibble, Eric *,1, Thomaz, Sidinei2, Higuti, Janet2, Padial, Andre2, Evangelista, Luiz2, 1 Mississippi State University, Mississippi State, MS, USA2 Universidade Estadual de Maringa, Maringa, Parana, Brazil
ABSTRACT- Aquatic plants are a key component of spatial heterogeneity in a waterscape, and contribute to the complexity in habitat that has long been considered a determinant of diversity and frequently inferred as a predictor of species richness at various spatial scales. Theoretically, the more complex a habitat, the higher number of species are present due to increased niche space. However, few empirical data are available to test this hypothesis in aquatic communities. We used a predictive approach and defined complexity as a fractal dimension (D) to investigate the hypothesis that complexity in vegetated habitat from two tropical lagoons (Brazil) mediates invertebrate diversity and density. In addition, we use a multi-scale approach to evaluate scale effect on available complexity in the vegetated habitat. A gradient of natural plant complexities was used to avoid sources of potential artificial interferences and we controlled for plant surface area and applied a residual analysis to disentangle confounding effects with collinearity between complexity and area. Effect of scale upon available complexity and interactions between plant species and scale were highly significant, and complexity (D) positively correlated with both taxa richness and abundance of macroinvertebrates. Our results represent the first empirical data from a tropical system suggesting that habitat complexity provided by the differential architectures among aquatic plants, significantly mediate both the richness and number of organisms. The use of fractal geometry to quantify spatial heterogeneity in habitat is useful in an empirical explanation of diversity and density of individuals within a tropical invertebrate community.
Key words: Aquatic, Habitat Heterogeneity, Species Richness