The perils of ignoring beta diversity when conducting applied research and developing management plans

Background/Question/Methods

While beta diversity is a major topic of study among ecologists seeking to understand basic patterns and processes, this component of biodiversity is often ignored by applied researchers, conservation planners, and land managers. This disconnect is particularly pronounced in tropical forests, where beta diversity is exceptionally high but frequently overlooked in applied efforts. We explored the implications of this disconnect via two related initiatives, one focused on research into the effects of logging, and one focused on spatiotemporal forest management strategies. The first initiative investigated rates and consequences of pseudoreplication, a methodological flaw that confounds treatment effects with pre-existing spatial variation (i.e. beta diversity). We reviewed all recent tropical logging-effects studies to assess the incidence of pseudoreplication, and analyzed an original multi-taxon dataset to explore the potential consequences of this flaw. For the second initiative, we developed and tested a novel conservation strategy for timber production forests that accounts for compositional variation among stands. This new approach assumes local harvest-induced extinctions will occur and uses strategic spatiotemporal harvest planning to facilitate re-colonization for as many species as possible.

Results/Conclusions

Our literature review results indicate that the vast majority of tropical logging-effects studies ignore beta diversity and implicitly assume logged areas were compositionally identical to unlogged areas prior to logging. Our empirical multi-taxon analyses demonstrate that accounting for pre-existing spatial variation dramatically reduces estimates of compositional changes resulting from logging. The results of our second initiative provide evidence that harvest plans informed by underlying compositional variation can improve biodiversity conservation in tropical production forest landscapes. Business-as-usual harvest plans are likely to synchronously disturb entire ranges of rare and/or clustered species, greatly increasing extinction risks; in contrast, strategic plans can minimize the number of species subjected to range-wide harvest. Taken together, these two projects suggest that selectively logged tropical forests have more conservation potential than generally assumed, but that this potential is not being fully realized. In summary, our findings demonstrate that the failure to account for beta diversity can undermine applied initiatives ranging from field studies to conservation-driven forest management efforts.