Surrogacy in invasion research and management: inferring “impact” from “invasiveness”

Abstract

Biological invasions are widely accepted drivers of biodiversity decline, yet the ecological impacts of invaders in many contexts remain largely unmeasured. Consequently, other measures of a species invasion (e.g. local abundance) are regularly used as surrogates (or ‘proxies’) to infer impact on recipient ecosystems. The use of surrogates for impact represents an implicit application of ecological surrogacy in invasion science, but without the evaluation and validation of surrogate-target relationships that characterizes surrogate use in other fields. While there are practical reasons for this, there also are risks associated with not testing the accuracy, stability and certainty of surrogate-impact relationships that need to be acknowledged. Recognizing the role of surrogacy in invasion science offers previously unappreciated solutions for increasing the quantitative rigor of invasive species impact assessments that inform management decisions. Show more