A Blast from the Past: Community Scale Impacts of Explosives Contaminated Soils after 17 years

Anthropogenically contaminated soils pose a significant threat to biota across the world. Much of the literature on explosives contaminated soils has focused on individual or species level impacts while the larger plant community is often ignored. Our goal was to fill that gap and investigate impacts on community structure and diversity in an area contaminated with three common explosive compounds (RDX, TNT, Composition B). Community data were collected from an experimental minefield that was cleared 17 years ago, seeded with a surveyed grid of explosive compounds, and allowed to naturally revegetate. Plots within contaminated and reference sites were established. Woody and herbaceous species composition was recorded and species diversity and richness were calculated. Species composition and functional type data were analyzed using cluster analyses, multi-response permutation procedure analyses (MRPP), and detrended correspondence analyses (DCA) to investigate separation of the treatment groups.

Classical diversity metrics were similar across treatments; however, cluster analyses and MRPP revealed significant differences in species and functional type composition. DCA of species composition showed no separation of treatment groups while DCA of functional traits showed that the TNT and Comp B plots contained a narrower range of functional traits, primarily due to life history and leaf characteristics, which differentiated them from the other treatment groups;. Differences between reference and contaminant sites in species composition and traits suggests that the presence of soil contaminants act as a physiological filter controlling which plant species establish and prosper. This in turn may have long lasting and significant impacts on the overall community composition and structure. Further research is needed to fully understand the community and ecosystem scale impacts of such contaminants.