The reintroduction of disturbance can play a critical role in restoring the community structure of degraded ecosystems. In the Midwestern United States, cedar glade habitats are threatened by long-term fire suppression. We used a multiscale analysis to test if the reintroduction of fire was sufficient to restore ant biodiversity in cedar glade habitats where fire had been excluded for many decades. We collected community data in 2013 and 2014 by sampling all ground dwelling and herbaceous dwelling ants by vacuuming all vegetation within one meter of transects located within eight restored glades and three remnant glades located near the Tyson Research Center outside of St. Louis MO. We used the R package mobr to estimate the importance of proximate drivers of richness, namely the species-abundance distribution, individual density, and intraspecific aggregation across a range of spatial scales using species accumulation curves.
Results/Conclusions
At the transect scale the restored glades had significantly lower average richness, total abundance, evenness, and estimated size of the species pool. These scale agnostic results suggest that the restored glades had lower biodiversity than the remnant glades. However, the multiscale analysis demonstrated that at coarser regional scales the restored glades had significantly greater ant richness due to increased ant species evenness. The multiscale analysis also revealed that the lower density effect observed at the transect scale was responsible for the depressed richness in restored plots. Both the evenness and abundance effects were stronger at coarser spatial scales indicating a signal of scale dependence. We did not observe a strong treatment difference in richness due to shifts in intraspecific aggregation between the restored and remnant glades. Overall it appears that the reintroduction of fire has not yet restored a key components of ant biodiversity - the abundance of ants which is responsible for lower ant richness at the patch scale, but fire reintroduction was successful in producing similar patterns of species spatial aggregation and increased evenness. A multiscale approach was key to revealing the scale dependent effects of restoration on this community.