COS 43-1
Putting biotic interactions into distribution analysis
Management and conservation strategies often build on species distribution models to further an understanding of threats and species ecology. Most of these models, however, ignore spatial autocorrelation and species co-occurrences. Such omissions affect statistical analyses and the ecological inferences drawn from them. To capture this complexity we use a recently developed Bayesian hierarchical multispecies model exploiting extensive monitoring data. We study the interaction between two polychaetes inhabiting intertidal sandflats, the predatory Nephtys hombergii and its prey, the deposit-feeding Heteromastus filiformis
Results/Conclusions
Sediment grain-size and depth explained a statistically significant portion of variability in abundance of Heteromastus and Nephtys. The median (and 95% credible interval) cross-correlation between Nephtys and Heteromastus was -0.68 (-0.83, -0.47). Because this interval excludes zero we can conclude that there is a strong negative association between these species after the environmental predictors were considered. Furthermore, they exhibited similar ranges of spatial autocorrelation: Heteromastus 6.24 km and Nephtys 6.29 km. An “interactor-as-predictor model” underlined these approaches do not allow partitioning environment factors and biotic interactions. Our results show the presence of species interactions beyond scales generally amenable to manipulative studies and provides a new approach allowing conservation research and measures to acknowledge and assess important ecological phenomena.