Effects of diversity on community assembly in newly formed pond communities

Theory suggests that in a new habitat, initial levels of genetic or species diversity can influence subsequent community assembly. Nevertheless, empirical investigations of these diversity effects in newly created habitats remain rare at both the genetic and species level, especially for animal systems. To test this theory, we conducted a field experiment in which initial stocking diversity (both intra-and interspecific) of freshwater zooplankton in newly constructed pools was manipulated in a 2 × 2 fully factorial design. Zooplankton communities were sampled every 2 weeks from May to August in 2011 and 2012, and once in May of 2013 and 2014. Estimates of overland dispersal were measured in 2012. Despite theoretical predictions, we found no difference in taxonomic richness among stocking treatments after 4 yr. A total of 24 species was recorded in the experimental pool metacommunity, with average cumulative taxonomic richness ranging from 6.1 to 7.6 species per pool. Using dispersal traps, we found that dispersal of zooplankton was rapid, with eight taxa dispersing within 7 d; we found no difference in the number of dispersed propagules based on number of neighboring source pools. Despite theoretical predictions regarding diversity and community assembly, our study suggests that initial diversity may have no effect on early successional community species richness.