The 2008 to 2012 National Invasive Species Management Plan called for the development of risk screening processes to evaluate the invasiveness of terrestrial and aquatic nonnative wildlife moving in trade. The Service developed ecological risk screening in response to this charge and has conducted an initial scan of tens of thousands of species, including 33,500 fish species from Fishbase alone. Based on evidence and expert opinion, the Service utilized history of invasion and anticipated harm to select approximately 1,725 species from the initial scan for further risk assessment through Ecological Risk Screening Summaries (ERSSs). Species posing broad risks to the United States were prioritized over species with expected localized or regional impacts.
The Service developed the ERSSs efficiently by using international databases, scientific literature, and a climate model. The climate model matches the basic climate requirements (temperature and precipitation) of a species in its native and known invasive ranges with similar climates in the United States to assess risk of establishment. The process is the same for species native to part of the United States, but also established in other parts of the United States outside their native range. The result provides an approximate geographic range in the United States where the climate is similar to where the species survives elsewhere; this is referred to as the species’ “climate match.” The Service has developed and peer reviewed a climate-matching program called the Risk Assessment Mapping Program or RAMP3 to conduct these climate matches.
We also obtain information on where the species has spread to other parts of the world outside of its native range and if it has established and caused harm there. We obtain information on what harm the species causes outside of its native range, such as the ability to outcompete native animals for food and rearing habitat, impacts to water quality, or the ability to spread pathogens that cause disease. We call this the species’ “history of invasiveness.”
Finally, we look at how certain we are that the information used for the climate match and history of invasiveness is scientifically credible, reliable, and of sufficient quantity to be used for the intended purpose. High certainty means that we are using scientifically credible and defensible information, data, and associated syntheses to draw clear and convincing conclusions about the species’ history of invasiveness and climate match with the United States. Medium certainty means that there is a preponderance of evidence relating to the history of invasiveness and the species climate match with the United States, and that the certainty of the assessment is neither high nor low. Low certainty means that limited or no information is available about the species for either variable. We call this “certainty of assessment” for the variables of history of invasiveness and climate match and is not considered in the Overall Risk Assessment.
The climate match in the United States and the history of invasiveness are combined to calculate the Overall Risk Assessment (which we sometimes refer to as simply “risk”). The risk categories are high, low, and uncertain. Please see the Standard Operating Procedures (SOP) for how each risk category is determined.
The “Standard Operating Procedures [SOP] for the Rapid Screening of Species’ Risk of Establishment and Impact in the United States” document was prepared by the Service and is intended to explain the purpose of the ERSS process and provide rigorous, repeatable steps necessary to obtain the species data to complete a risk assessment. Key goals of this specific SOP are to standardize data collection and interpretation of risk assessments and to assure the credibility of resulting reports for transparency and repeatability.
The public is encouraged to use the following email address to submit information on the ERSS reports that might help to improve the accuracy of the assessment: firstname.lastname@example.org
The Service uses these ERSSs in two ways:
The aquatic based ERSSs will be posted on this site as they are finalized. Because categorizing ecological risk is based on the current understanding of ecological conditions and species preferences, new information could change the ERSS results. Therefore, please check the ERSS website periodically to obtain the most current information.