Diversity, similarity and resilience of arthropods in response to the restoration of former pine plantations

Background/Question/Methods The goal of ecological restoration is to return degraded or altered ecosystems to their pre-disturbed state with respect to ecosystem structure, function, and composition.  In the current study the research objective is to reestablish high levels of biodiversity on two restored pine plantations.  Managed, even-aged pine flatwoods are now the most extensive ecosystem in North Florida, comprising approximately 70% of the forested landscape.  In an attempt to facilitate this establishment of higher levels of diversity on these former pine plantations manipulations of the current plant communities were first undertaken.  Slash pine trees were thinned in the experimental plots so as to restore the natural slash pine density of native ecosystems.  In addition to the thinning treatments, experimental plots have been clear-cut and all vegetation removed from the plots.  Insects were sampled by employing pitfall traps, sticky traps and sweep netting.  This study assesses the success of the restoration techniques employed by looking at biodiversity with a fine-resolution, taxonomically narrow approach by identifying the arthropods down to the taxonomic level of family and determining the number of morphospecies.  Species were also subdivided into functional groups based upon the ecosystem services that they provide and their trophic level.

Results/Conclusions Analyses revealed that arthropod species and guild diversity was not significantly affected by treatments in both 2008 and 2009.  Although the experimental treatments were not higher in terms of diversity than the control plots there are still some positive results in regards to diversity.  The experimental treatments were able to recover to pre-disturbance levels after two years following restoration.  This indicates that these arthropod communities are fairly resilient and are able to recover fairly quickly following perturbation.  Interestingly, community similarity measures revealed that although the experimental treatments were no more diverse than control plots the community species composition was fairly dissimilar between treatments, with plots becoming more dissimilar from 2008 to 2009.  More long term data should reveal if these plots are proceeding along different successional trajectories in terms of community species composition and also will allow us to gain more insight into the long term effect of the treatments on biodiversity.