Comparing methods, species distribution data and spatial resolutions: Peninsula effect study on amphibian of Malay Peninsula

In macroecological studies, accurate species distribution information and reliable methodologies are essential to illustrate the accurate geographical distribution of organisms. The available distribution data sources are generally limited to a particular geographical region and studied taxa and often contain some degree of sampling bias that caused a misrepresentation of species distribution. This study investigates how the different distribution data, methods, and spatial resolution affect the amphibian distribution pattern in the Malay Peninsula. Five types of distribution data, namely point-based (simple point occurrences and rarefied point occurrences) and range-based (expert-drawn range map, modelled range map and hybrid range map), were assembled from the published checklist, GBIF, natural history museum collections information, and digital range maps. Species richness was point-to-grid mapped by overlaying each distribution data with spatial resolutions of 100 km, 75 km, 50 km, 25 km and 15 km square grid and were evaluated with descriptive and quantitative-based approaches. Overall results show that richness maps created from range-based maps well-performed both descriptive and quantitative. Spatial autocorrelation was present in all distribution data; however, it is significantly reduced in 50 km resolution in range-based maps. When mapped with different spatial resolutions, the hybrid range map showed less variability in spatial relatedness and structure and executed a better predictive performance. The findings suggested that integrating the information from other distribution sources reduces the erroneous information in particular distribution data and can also evaluate the effects of spatial resolutions before developing species distribution maps.