It is well understood that complex abiotic and biotic factors influence soil dynamics. To better understand these interactions the ability to discuss focal taxa at a species level could be incredibly informative, albeit difficult to accomplish due to limited knowledge of existing taxa diversity. The utilization of microhabitats by different species may be important in explaining community compositions among forest types. Collembolans represent a unique focus group to help understand soil dynamics because they respond strongly to physico-chemical and/or biological changes that occur within environments even over a small geographic range. This study was conducted along an altitudinal gradient in the Luquillo Mountains of Puerto Rico. We sampled in tabonuco (Dacryodes excelsa, 300-520 masl) palo colorado (Cyrilla racemiflora, 750-820 masl) and elfin (Tabebuia rigida,950-1050masl) forest types. Sampling occurred in nine plots every four months from August 2014 to August 2015, with three plots in each forest type. In each plot, we selected five trees of the dominant species and sampled soil, leaf litter and epiphytes from the adjacent area of each tree. Berlese funnels were used to extract all arthropods and collembolans were identified to species
In total, 8335 collembolans were collected and found to represent 74 species that belong to 14 families. Community composition varied among forests, in species richness and abundance. According to an analysis of Non Metric Multidimensional Scaling (NMDS) there was a clear separation of Collembola communities in the elfin forest compared to those of tabonuco and palo colorado forests. Species richness among forests and microhabitats were found to be significantly different (Two-Way ANOVA; p< 0.005). These results show the importance of several microhabitats for collembolans, especially epiphytes in the elfin forest, which were found to contain high levels of diversity. Overall, species richness was not significantly different among some microhabitats and forests. For soil samples we found one endemic species, while in epiphytes 10 species were found exclusively for this microhabitat. Moreover, the elfin forest showed a species richness of 52 and was the forest type with the highest number of endemic species (8). In previous studies 44 Collembola species were reported for the Luquillo Mountains. However, in this study we discovered 22 new reports for species in Puerto Rico and at least 8 new species to science. This study highlights the dearth of taxanomic information for collembolans in tropical forests and the importance of certain microhabitats that showed high levels of endemicism.