Taxonomic Diversity and Influence of Environmental Factors on Collembola (Arthropoda: Hexapoda) Communities of Ilha das Canárias, Maranhão, Brazil
Conservation; communities; marine environment; soil fauna; springtails.
This study aimed to provide a faunal survey of the Collembola in the Environmental Protection Area of the Parnaíba Delta – Ilha das Canárias, and to describe how the richness and abundance of their populations are affected by seasonal variations, environmental variables, and spatial characteristics of the region. For specimen sampling, two collections were carried out, one in the rainy season and another in the dry season, with five sampling points containing pitfall traps along a 200 m transect in each phytophysiognomy. Data on environmental variables (air and soil temperature, pH, vegetation richness, soil moisture, organic matter, canopy cover, and soil texture) were collected. The collected material was sorted, morphotyped, and mounted on slides for taxonomic identification. Alpha diversity was quantified using species richness and diversity indices (Shannon-Weaver, Simpson, Pielou), while Whittaker's index was used to estimate Beta diversity. Abundance and α diversity were individually assessed in relation to space-time factors through Mixed Generalized Linear Models and Permutational Multivariate Analysis of Variance for β diversity. Non-metric Multidimensional Scaling was used to plot the biotic data matrix in relation to space-time factors. Finally, the abundance of each taxon was related to the sampled environmental variables through Redundancy Analysis. A total of 5,350 specimens were collected, representing three orders, eight families, 23 genera, and 31 morphospecies and one nominal species. In the dry season, 2,205 individuals were collected, representing three orders, six families, 16 genera, and 21 morphospecies. The highest abundance was observed in Riparian Forest (1147), followed by Restinga (934) and Mangrove (89). In the rainy season, a total abundance of 3,145 individuals was collected, representing three orders, eight families, 19 genera, and 25 morphospecies. Restinga showed the highest abundance (1513), followed by Mangrove (1339) and Riparian Forest (291). Riparian Forest presented the highest α diversity values with higher species richness. β diversity was recorded at higher values in Mangrove. The environmental variables vegetation richness, soil moisture, and litter significantly influenced the species Dicranocentrus sp.1, Proisotoma sp.1, Lepidocyrtus sp.3, and Salina sp.1; while Seira sp.2, Pseudosinella sp.1, and Seira sp.1 were positively associated with soil temperature, air temperature, and pH. Other species showed low explanatory power with the analyzed environmental variables. This study represents an initial effort to understand a unique fauna with potentially several new species in a previously unexplored ecosystem.