Northern Diamondback Terrapin Probability of Occurrence (POC) Model for MA, RI, CT, NY, NJ, DE, MD, and VA. Warmer colors represent greater values and therefore, a higher probability of terrapins occurring in that area. The POC was developed by Karen Leu and Brooke Maslo (Rutgers University) and is based on documented occurrence between the years 2000-2012 as well as several environmental variables (see full report by S. Egger, 2016). The POC figure is the raw Maxent output. It contains the predicted probability of occurrence on a 0 - 1 scale, with 0.7722 being the highest possible value. Thresholds of 0.5, 0.6, and 0.3188 are shown. The latter value is the 10th percentile training presence logistic threshold, which was generated by Maxent. It is considered a relatively conservative threshold and has been used as an indicator for suitable habitat in other studies.Documented occurrences of terrapins depicted in this map include those prior to 2000 and after 2012, as well as additional points not used to create the POC model. Occurrence data provided by the Diamondback Terrapin Working Group.

The point layer represents documented occurrences of the northern diamondbackback terrapin (Malaclemys terrapin terrapin) from Massachusetts in the north to Virginia in the south. Multiple data sources were used to compile this data: for specific source information, consult the final report of the Northern Diamondback Terrapin Regional Conservation Strategy. This data set exists as two separate layers: points and polygons. Compilation of this data set began in 2015 and was finalized on March 2, 2015 by the Conserve Wildlife Foundation of New Jersey.

For more information on the Northeast Regional Diamonback Terrapin Conservation Strategy: http://rcngrants.org/content/northern-diamondback-terrapin-malaclemys-terrapin-terrapin-ne-united-states-regional