Scenario Analysis of Management Alternatives for Free-roaming Horse Populations (Version 1.0.0)

PopEquus is a predictive modeling tool to support decisions related to the management of free-roaming horse populations. It permits the simulation and comparison of how management alternatives influence horse population size and metrics associated with management. This repository uses R scripts with predictive functions from the PopEquus model to simulate how management alternatives (e.g., removing horses, treating females with fertility reducing vaccines, etc.) influence population size, metrics related to animal handling, and fiscal costs of management. The code and functions rely largely on tools from the R package 'popbio' to use matrices to projection populations. This repository includes code that performs statistical analyses and makes graphs and tables to visualize the results. For this analysis, we used predictive functions that estimated how six management actions (removals for adoption, treatment with three fertility reduction vaccines [GonaCon-Equine, PZP-22, or Zonastat-H], treatment with intra-uterine devices [IUDs], and treatment with mare sterilization) - used alone or in concert with other actions - influenced horse population size and management costs. The script compares alternative management scenarios at two, three, and four-year return intervals over 10-year and 20-year periods. Results can be used to evaluate the utility of alternative for reducing population size to within management targets while minimizing other metrics, such as animal handling and cost. The analysis is part of a manuscript describing the consequences of alternatives in horse population management: Folt, B., K.A. Schoenecker, L.S. Ekernas, D.R. Edmunds, and M. Hannon. PopEquus: a predictive modeling tool to support management decisions for free-roaming horse populations.