photo by USFWS Improved ESA Implementation through photo by USFWS Species Distribution Modeling Karner Blue Butterfly Regan Smyth and Healy Hamilton, NatureServe Decurrent False Aster Lycaeides melissa samuelis, Listed Endangered decurrens Listed Threatened The Problem Pilot Outcomes A lack of precise information on where federally listed species Today, input data are readily available, and modeling procedures are standardized. occur inhibits effective species conservation and creates unnec- It is now entirely feasible to generate refined maps of the distribution of suitable essary regulatory burdens. The status quo of using broad range habitat for almost all T & E species through a vetted, dynamic, and transparent maps to identify impacts to listed species results in many “may scientific process, andpilot projects have demonstrated the potential of SDM to affect” or “likely to adversely affect” determinations. Although streamline environmental reviews, including aspects of the consultation FWS provides refined maps for some species, the data are incon- process. sistent across taxa and not transparent for the regulated commu- nity or conservationists. Without consistent, predictable, up-to- A project assessing the potential of SDM to improve the pesticide consultation pro- date, and scale-appropriate information to guide ESA decisions, cess found that for Boltonia decurrens, a threatened found in agricultural significant funding is spent analyzing effects that may never occur An example of the coarse landscapes along the River floodplain, using an SDM resulted in 10,000,000 Comparison of the total area, in acres, of habitat mapped for Boltonia on the ground. range data currently being fewer acres of identified habitat than the species range used by FWS.This repre- decurrens, (1) by using NatureServe current and historic element oc- used for ESA screenings. currence (EO) records, (2) as maintained by FWS, (3) as maintained by sents a 95% reduction in the area used to determine potential pesticide impacts. the Federal Endangered Species Task Force, and (4) with a species dis- The same model demonstrated to ease regulatory burdens is being used to advance tribution model using a protective threshold. The Solution conservation efforts. The Partners for Fish and Wildlife in Illinois plan to use the Advances in ecological modeling make the current lack of precise distribution maps a model to prioritize outreach and financial assis- tractable problem to solve. A nationally consistent, verifiable, multi-jurisdictional li- tance to landowners in an initiative to increase high brary of modeled distributions for listed, candidate, and petitioned species can now be -quality, native waterfowl food and habitat for the achieved by applying scientifically robust species distribution modeling (SDM) tech- species. Without the new map, directing those re- niques. SDM combines species observation data with environmental predictors to map sources to areas of high impact would be a signifi- areas of likely occurrence. cant challenge.

Where models exist, FWS field offices have accept- Elevation ed them as the best available science, but else-

Climate where, data remain coarse. A comparison of FWS range data for the Karner blue butterflyLycaeides ( melissa), which has been modeled in New York but Soils not in other states, makes clear the discrepancy in Land Cover data precision with and without models. When po- tential pesticide application areas are overlaid on the model, the consequences for regulatory compli- Species Observation Points Examples of input layers used The FWS mapped range for the Karner blue butterfly. In New York, where the New York Natural Heritage Pro- for Meadii, a threat- to characterize the environ- ance become clear: areas of conflict between likely gram modeled habitat for the species, the mapped range is precise (inset) while elsewhere, broad county ened milkweed found in agricul- mental setting boundaries define habitat. In the inset, orchards, a proxy for pesticide use areas, are shown in green. tural lands in the Midwest species presence and use areas are relatively few.

Products include maps of habitat suitability and probable habitat/non-habitat. Next Steps Maps of Habitat Suitability Habitat Maps From low to high across the land- Binary map of habitat/non-habitat NatureServe has identified 325 listed or petitioned species scape (above right) (below right) in the lower 48 states that are ideally suited for SDM given current data availability, and over 500 more that are good In areas of low suitability, confi- Created from modeled probabilities based on sci- candidates for modeling provided some additional invest- dence that the species is not pre- entific standards and user-defined risk tolerance, ment in data development (right). In addition to streamlin- sent is high, while areas of high habitat maps can be tai- ing ESA consultations, completing models for these species suitability can guide priorities for lored to regulatory can: survey, protective measures, and needs.  Inform listing decisions restoration.  Guide avoidance and mitigation strategies Asclepias meadii habitat map  Support species recovery efforts Suitable Habitat  Focus conservation initiatives  Direct inventories and locate new populations Not Suitable Habitat