Toxicity – biodiversity relationships unravelled

Toxicity – biodiversity relationships unravelled

ecol lettersThe production and use of chemicals is regulated by environmental legislation so as to protect the diversity of our surface waters. Until recently, however, it was impossible to predict the relationship between chemical toxicity and the diversity of aquatic communities, which hampered effective environmental conservation. Together with an international consortium, the laboratory of environmental toxicology (, UGent) developed the first theory to predict biodiversity along gradients of toxic stress. Combining this theory to data from polluted algal communities, the scientists reveal that the variability of toxicity tolerance in these communities is five to ten times higher between individuals from the same species than between individuals from different species. The results of this research also demonstrate that this 'within-species variability' is a buffer against species loss in ecosystems polluted with chemicals. These findings, which have been published in the nr 1-ranked ecology journal 'Ecology Letters', raise important concerns regarding the use of species-based tolerance data for environmental protection and explain ecosystem resistance during chemical spills.


Scientific abstract

The worldwide distribution of toxicants is an important yet understudied driver of biodiversity, and the mechanisms relating toxicity to diversity have not been adequately explored. Here, we present a community model integrating demography, dispersal and toxicant-induced effects on reproduction driven by intraspecific and interspecific variability in toxicity tolerance. We compare model predictions to 458 species abundance distributions (SADs) observed along concentration gradients of toxicants to show that the best predictions occur when intraspecific variability is five and ten times higher than interspecific variability. At high concentrations, lower settings of intraspecific variability resulted in predictions of community extinction that were not supported by the observed SADs. Subtle but significant species losses at low concentrations were predicted only when intraspecific variability dominated over interspecific variability. Our results propose intraspecific variability as a key driver for biodiversity sustenance in ecosystems challenged by environmental change.


Full reference

De Laender F, Melian CJ, Bindler R, Van den Brink PJ, Daam M, Roussel H, Juselius J, Verschuren D, Janssen CR. 2013. The contribution of intra- and interspecific tolerance variability to biodiversity changes along toxicity gradients. Ecology Letters. In press. doi:10.1111/ele.12210