Mapping potential butterfly milkweed (Asclepias tuberosa) habitat in Mississippi using Species Distribution Modeling (SDM) and Geographic Information Systems (GIS)

Abstract

A Geographic Information System (GIS) algorithm can map and quantify suitable butterfly milkweed (Asclepias tuberosa L. [Asclepiadaceae]) sites based on the species environmental preferences, including soil pH, soil texture, and land cover type. Asclepias tuberosa is a primary larval food source for the monarch butterfly (Danaus plexippus L. [Lepidoptera: Nymphalidae]). Planting more A. tuberosa may support declining monarch populations. We created a GIS A. tuberosa habitat suitability map for Mississippi using soil pH, soil texture, and land cover. We derived herbarium data from the Southeast Regional Network of Expertise and Collections (SERNEC) database. Environmental data were from the USDA Natural Resources Conservation Service Geospatial Data Gateway. We used frequency analysis to assign scores to environmental variables of SERNEC occurrences using a suitability index. Global Positioning System (GPS) locations of A. tuberosa were collected to validate the model based on the SERNEC herbarium occurrences. The model with highest habitat suitability with 78.9% of GPS points in medium to high suitability was a weighted sum overlay with land cover 50%, soil pH 25%, and soil texture 25%. The suitability map can be used as a tool to identify suitable sites for future outplantings or surveying of A. tuberosa in Mississippi.