Comparing apples to oranges and other misrepresentations of the risk screening tools FISK and AS-ISK – a rebuttal of Marcot et al. (2019)

Abstract

Marcot et al. (2019) recently described the risk analysis process by which the U.S. Fish and Wildlife Service (USFWS) chooses species for listing as injurious wildlife. They further compared the Fish Invasiveness Screening Kit (FISK) and the Aquatic Species Invasiveness Screening Kit (AS-ISK), generally unfavorably, with their process/components. We assert that FISK and AS-ISK were largely misrepresented. The USFWS process is a risk analysis framework, whereas FISK and AS-ISK are hazard identification/risk screening tools, addressing only the initial step of a risk analysis scheme. Thus to avoid an apples-to-oranges comparison as done in that paper, FISK/AS-ISK should be compared to the equivalent USFWS tool, the Ecological Risk Screening Summaries (ERSS). The remaining issues that we address concerning FISK/AS-ISK include: (1) need for expert opinion, (2) subjective climate matching, (3) need for regional calibration, and (4) narrower range of information inputs; and concerning the ERSS process: (5) peer-review. Both systems clearly use expert opinion, the FISK/AS-ISK arguably in a more structured and transparent manner. Guidance for FISK/AS-ISK recommends a climate-matching program, but allows for use of Köppen-Geiger climate types or physiological tolerances, potentially increasing subjectivity in some cases but improving climate-match quality in others. Calibration of FISK/AS-ISK follows from the regional nature of invasiveness risk and the use of questions unrelated to climate that are tailored to the risk assessment (RA) area. Climate match is the only element that the ERSS applies specifically to the RA area. The FISK and AS-ISK actually use a much wider range of information than does the ERSS, a system based on invasion history and climate match only. The peer review of ERSS consisted of a five-member expert panel that evaluated the method, whereas the ERSS reports posted online are not peer reviewed. Conversely, FISK applications have resulted in 37 peer-reviewed journal articles, including assessments from over 70 experts in 45 countries. We welcome constructive criticism and improvement of these decision-support tools, but we are concerned that managers may dismiss well-established approaches in favor of a framework that possesses its own method-specific limitations. We recommend that managers evaluate risk-based approaches and adopt systems to support decisions and improve invasive species management.