Relation between the Structure of Mangrove Forests and Geomorphic Types of Lagoons of the Baja California Peninsula

Abstract

González, P.; Lluch-Cota, S.E., and Nava-Sánchez, E.H., 2013. Relation between the structure of mangrove forests and geomorphic types of lagoons of the Baja California Peninsula. There are limited studies involving geomorphic factors and ecological patterns on a landscape scale of coastal features. This study examines the hypothesis that the structure of mangroves varies with habitat type. Using geomorphic criteria, we identified and classified 51 lagoons that contain mangroves on the Baja California Peninsula. Four lagoon types were analyzed: open drowned valley (I-A), barred drowned valley (I-C), Gilbert de Beaumont barrier lagoon (III-A), and cuspate lagoon (III-B). Structure patterns of mangrove forests growing at the edge of the lagoons were identified through photo interpretation and field observations, using landscape indices related to (1) area, density, and variability of the patches; (2) ecotone; and (3) form. Multivariate and univariate analyses were performed to determine the effects of habitat types on mangrove structure. Cluster analysis based on structural similarity showed two groups: (A) forests with limited structural development that grow mostly at the shore of lagoons I-A and I-C, and (B) larger forests with numerous patches, larger average size, average perimeters, and simpler forms than those in the first group, which grow mostly in lagoon type III-A. Similarity analysis showed no differences between the forests of lagoon types I-A and I-C, but there were differences between these two types and type III-A. Variance analysis showed differences in area, perimeter, and the shape of patches with respect to habitat type. Tukey's Honestly Significant Difference post hoc tests confirmed previously identified groups and showed that forest patches in lagoon type III-B are of intermediate structure. Lagoon type III-A appear to be more important in distribution and development of mangrove forests. Finally, we found that the spatial scale analyses and use of geomorphologically defined habitats were effective approaches for a first-order differentiation of mangrove forests.