Deconstructing the surrogate species concept: a life history approach to the protection of ecosystem services

Abstract

The use of the surrogate species concept is widespread in environmental risk assessment and in efforts to protect species that provide ecosystem services, yet there are no standard protocols for the choice of surrogates. Surrogates are often chosen on the basis of convenience or vague resemblances in physiology or life history to species of concern. Furthermore, our ability to predict how species of concern will fare when subjected to disturbances such as environmental contaminants or toxicants is often based on woefully misleading comparisons of static toxicity tests. Here we present an alternative approach that features a simple mathematical model parameterized with life history data applied to an assemblage of species that provide an important ecosystem service: a suite of parasitoid wasps that provide biological control of agricultural pests. Our results indicate that these parasitoid wasp species have different population responses to toxic insult--that is, we cannot predict how all four species will react to pesticide exposure simply by extrapolating from the response of any one species. Furthermore, sensitivity analysis of survivorship and reproduction demonstrates that the life stage most sensitive to pesticide disturbance varies among species. Taken together, our results suggest that the ability to predict the fate of a suite of species using the response of just one species (the surrogate species concept) is widely variable and potentially misleading.

Time will tell: resource continuity bolsters ecosystem services

“…On the basis of this information, hypotheses on resource bottlenecks can be formulated. Before they are tested in experiments it is efficient to first test them in silico through sensitivity analyses or scenario projections in general population models that demand relatively few estimated parameters (e.g., [33,34]). …”

Are honeybees suitable surrogates for use in pesticide risk assessment for non‐Apisbees?

“…This also holds true for the ∼ 2000 bee species recorded in Europe and an estimated up to 20 000 bee species worldwide. 25,26 Although the use of surrogates in assessing impacts on ecosystems services has been challenged, 27 it remains a widely accepted concept in pesticide risk assessment. Surrogate species for use in pesticide risk assessment are usually selected from those that are readily available year-round, adaptable for use under laboratory conditions and ideally relatively sensitive.…”

Limitations in dose–response and surrogate species methodologies for risk assessment of Cry toxins on arthropod natural enemies

“…This relies on two key assumptions: individual responses to uniform and constant exposure are unimodal, and the surrogate accurately predicts responses of other taxa. The unimodal response presumption has not been evaluated for non-target effects of GM plants, and extrapolation based on surrogate species has been shown to be inaccurate (Suter 2007;Banks et al 2014) and imprecise (Elmegaard and Akkerhuis 2000).…”