A preliminary assessment of spatial patterns of soil ciliate diversity in two subtropical forests in Puerto Rico and its implications for designing an appropriate sampling approach

Soil ciliates have been associated with key ecosystem processes, such as nutrient cycles and primary productivity. However, the significance of ciliate biodiversity and the mechanisms underlying the role of ciliates in ecosystem functioning remain unknown. In order to understand the relationship between soil ciliate biodiversity and soil ecosystem functioning in natural landscapes it is first necessary to determine the fine-scale distribution of their species diversity. A geostatistical approach was used to determine the level of spatial dependence and heterogeneity in ciliate diversity through semivariograms derived from two stratified plots in two subtropical forests in Puerto Rico. Both plots revealed a high degree of spatial heterogeneity with spatial dependence up to 8 and 3 m in the serpentine and limestone substrates, respectively. There were scattered hot spots in species richness, suggesting the need for a directed and standardized sampling design. Random sampling could obscure significant interactions, rendering the association between ecosystem functioning and ciliate diversity in temperate and tropical systems hard to interpret.