Use of Generalized Dissimilarity Model for Analyzing Environmental Drivers of Marine Beta Diversity and Bioregionalization in Lesser Sunda Island

The diversity and density of marine organisms have gradually declined due to prolonged human influences on the ocean and climate change pressures. Complex marine organism diversity distribution is linked with beta diversity. The environmental factors influence the pattern of marine beta diversity in the aquatic system. In this study, we aim to analyze the environmental drivers of beta diversity pattern of Lesser Sunda Island by using generalized dissimilarity model (GDM) approach. This technique employs nonlinear basis (I-spline) functions, which recognized to be a good fit for common compositional and environmental patterns than linear models. Lesser Sunda Island is located in coral triangle area that prioritized for global marine conservation. The observed beta diversity was computed from species occurrence data retrieved from Ocean Biodiversity Information System (OBIS) database, while environmental variables derived from MARSPEC and Bio-Oracle database. The result showed deviance explained percentage of GDM was 44.284%. It also revealed that nitrate, pH, salinity, and SST as the main driver of beta diversity in Lesser Sunda Island. Furthermore, we used the predicted beta diversity resulted from GDM to create bioregion as well as evaluate the representativeness of current marine protected area (MPA), which were indicate a gap in marine conservation area in study region.