Biodiversity-ecosystem function (BEF) theory and wetland restoration

Abstract

Biodiversity-ecosystem function (BEF) theory was founded on the idea that levels of ecosystem functions (e.g., productivity, nutrient cycling, decomposition) and the stability of those functions depend directly on levels of biodiversity, including diversity of all biota at the level of genotypes, species, and functional groups (sets of physiologically or morphologically similar species). Ecosystem functions are typically estimated from measures of stocks, e.g., plant biomass or nutrient crop, in response to vascular plant diversity (which can be easily manipulated in experiments). To date, the vast majority of experimental tests indicate that, on average, diversity increases productivity. Experimental outcomes have prompted BEF researchers to call on restoration ecologists to apply BEF theory by establishing more diverse biotic communities to increase ecosystem function. Using BEF theory relevant to its application, outcomes from experiments testing that theory with wetland plants and outcomes from experiments for wetland restoration projects suggest that a major challenge in applying BEF theory in wetlands is to establish and maintain plant diversity. However, applying BEF theory in wetland restoration does not simply mean adding more species to plantings, but to further explore how plantings can help achieve target ecological functions. Field experiments that vary plant composition and diversity, or that indirectly increase bird, insect, and bacterial diversity, would advance the practice of wetland restoration while ground-truthing BEF theory.