Plant traits – A tool for restoration?

Question: Most results of restoration efforts are species-specific and/or site-specific and therefore are not general enough to be easily applied to other species and other sites. Our research addresses the issue of species-specific results by investigating the feasibility of using plant traits instead of taxonomic identity to characterize species responses to restoration treatments.

Location: Ten bunchgrass prairie sites in the Pacific Northwest of North America (Oregon and Washington, USA; British Columbia, Canada).

Methods: We developed two types of quantitative models for each of ten prairie restoration sites: (1) plant trait models, which related plant traits to species field responses following restoration management treatments; and (2) species identity models, which related species taxonomic identity to species field responses following restoration management treatments. Species identity models determined the maximum amount of variability of field responses that can be explained by differences in individual species’ responses to management treatments. Plant trait models determined what proportion of this explanatory power can be attributed to plant traits. The two model types addressed the following specific questions: (1) how much of the variability in field responses (changes in cover) of plants to restoration management treatments is explained by plant traits; and (2) how well do plant traits explain the variability of field responses (changes in cover) following restoration management treatments compared to models relating field responses to species identity?

Results: (1) The plant trait models explained much of the variability within each of the ten restoration sites, with R2 values ranging between 31%and 69%. (2) The species identity models explained between 47% and 74% of variability of change in cover (R2). Thus, the plant trait models explained nearly as much variability as the species identity models. In seven out of nine sites, the plant trait models were superior to the species identity models, as measured by AIC, i.e. the trait models did well at explaining variability with less model complexity.

Conclusion: Strong explanatory power of plant trait models supports the feasibility of using plant traits instead of species taxonomic identity as a common language to characterize plant field responses (changes in cover) to restoration treatments.