Multiple metrics quantify and differentiate responses of vegetation to composition B

Abstract

Quantifying vegetation response to explosive compounds has focused predominantly on morphological impacts and uptake efficiency. A more comprehensive understanding of the total impacts of explosives on vegetation can be gained using a multivariate approach. We hypothesized that multiple variables representing morphological and physiological responses will more clearly differentiate species and treatments than any single variable. Individuals of three plant species were placed in soils contaminated with Composition B, which comprises 60% hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 40% 2,4,6-trinitrotoluene (TNT), and grown for 2 months. Response metrics used included photosynthetic operation, water relations, growth characteristics, as well as nitrogen and carbon concentrations and isotopic compositions. Individual metrics showed high variability in response across the three species tested. Water relations and nitrogen isotopic composition exhibited the most consistent response across species. By comparing multiple variables simultaneously, better separation of both species and exposure was observed. The inclusion of novel metrics can reinforce previously established concepts and provide a new perspective. Additionally, the inclusion of various other metrics can greatly increase the ability to identify and differentiate particular groups. By using multivariate analyses and standard vegetation metrics, new aspects of the vegetation response to explosive compounds can be identified.

Legacy Effects of Explosive Contamination on Vegetative Communities

“…TNT plots showed a novel shift in functional dominance, via CWM values, with the significant increase in C 4 plant presence. This dominance of C 4 species in TNT plots is particularly interesting as TNT induces significant impacts to photosynthetic mechanisms yet C 4 species appear to be more tolerant overall to presence of explosive compounds, and may have led to this shift [69].…”

Right on target: using plants and microbes to remediate explosives

“…Novel studies have quantified the response to explosives of plant species native to military ranges in temperate regions. By measuring multiple variables representing morphological and physiological responses, such studies identified vegetation responses that could potentially be used to determine levels of TNT and RDX contamination (Ali et al 2014;Via and Zinnert 2016;Via et al 2017Via et al , 2015. Hyperspectral imaging technologies are also being developed to remotely detect vegetation response (Naumann et al 2010) using aerial drones as suitable carriers to record contamination levels on surfaceinaccessible sites.…”