DOI: 10.5061/dryad.7dh4312
title: Data from: Integrating encounter theory with decision analysis to evaluate collision risk and determine optimal protection zones for wildlife

description: 1. Better understanding human-wildlife interactions and their links with
 management can help improve the design of wildlife protection zones. One
 important example is the problem of wildlife collisions with vehicles or
 human-built structures (e.g. power lines, wind farms). In fact, collisions
 between marine wildlife and watercraft are among the major threats faced
 by several endangered species of marine mammals. Natural resource managers
 are therefore interested in finding cost-effective solutions to mitigate
 these threats. 2. We combined abundance estimators with encounter rate
 theory to estimate relative lethal collision risk of the Florida manatee
 (Trichechus manatus latirostris) from watercraft. We first modeled
 seasonal abundance of watercraft and manatees using a Bayesian analysis of
 aerial survey count data. We then modeled relative lethal collision risk
 in space and across seasons. Finally, we applied decision analysis and
 Linear Integer Programming to determine the optimal design of speed zones
 in terms of relative risk to manatees and costs to waterway users. We used
 a Pareto efficient frontier approach to evaluate the performance of
 alternative zones, which included additional practical considerations
 (e.g. spatial aggregation of speed zones) in relation to the optimal zone
 configurations. 3. Under the various relationships for probability of
 death given strike speed that we considered, the current speed zones
 reduced the relative lethal collision risk by an average of 51.5% to 70%
 compared to the scenario in which all speed regulations were removed (i.e.
 the no-protection scenario). We identified optimal zones and near-optimal
 zones with additional management considerations that improved upon the
 current zones in terms of cost or relative risk. 4. Policy Implications:
 Our analytical framework combines encounter rate theory and decision
 analysis to quantify the effectiveness of speed zones protecting manatees
 while accounting for uncertainty. Our approach can be used to optimize the
 design of protection zones intended to reduce conflicts between human
 waterborne activity and marine mammals. This framework could be extended
 to address many other problems of human-wildlife interactions, such as the
 optimal placement of wind farms to minimize collisions with wildlife or
 the optimal allocation of ranger effort to mitigate poaching threats.
description: Udell_et_al_AnalysisPlease cite the original publication when referencing these methods. This folder contains all data, Rcode, and JAGS code needed to run each analysis from Udell et al. 2018. These analyses include modeling the abundance of manatees and boats in space and time using a Bayesian approach; modeling the lethal collision risk to manatees on a fine scale under different boat speed zones; and determining the optimal protection zones using Linear Integer Programming to balance the trade off between risk to manatees and burdens to waterway users. These analyses are organized into 4 different folders: 1) a folder with data and code to run a Bayesian analysis of abundance (using informative priors) using multi-season and single season N-mixture models of the hurdle variety (used to model abundance of manatees). 2) a folder with data and code to run a Bayesian analysis of abundance (using informative priors) using a multi-season hurdle model (used to model abundance of boats), 3) a folder with data and code to model the lethal collision risk between boats and manatees on a fine spatial scale while accounting for uncertainty. Also contains code to determine the optimal speed zones using Linear Integer Programming. 4) a folder with data and code to spatially smooth the optimal zones. See the corresponding publication, and especially the supporting information for more details on the methods.