Date of Award

Spring 4-17-2020

Semester of Degree

May

Document Type

Open Access Dissertation

Degree Name

Ph.D. in Environmental and Forest Biology

Department

Forest and Natural Resources Management

Major Professor

Jonathan Cohen

Steering Committee Member

Abby Darrah

Steering Committee Member

Brooke Maslo

Steering Committee Member

Shannon Farrell

Abstract

Successful recovery of endangered species requires an understanding of factors that limit population size and growth rate. Regulatory protection and management interventions for piping plovers have been largely successful in recovering populations throughout the breeding range; however, some subpopulations have not recovered, including the New Jersey population. The goal of this study was to understand how predators, foraging habitat, and management actions affect piping plover population dynamics in New Jersey. Using resighting data, we found that adult survival between 2012–2019 ranged from 0.62 [95% CI = 0.48, 0.74] to 0.85 [0.74, 0.92] for females and 0.65 [0.51, 0.78] to 0.89 [0.80, 0.94] for males and juvenile survival ranged from 0.40 [0.30, 0.51] to 0.70 [0.57, 0.80]. Abandoned nests were associated with lower survival rates, particularly for males. Daily chick survival rates increased with age (days since hatching), decreased with daily precipitation, and were lower when bayside foraging access was not available. Using predator tracking surveys and occupancy modeling, we found that mink occupancy was higher when red foxes were absent (0.787 [95% CI = 0.14, 0.98]) than when they were present (0.05 [0.01, 0.26]). Daily nest predation was similar at sites with red foxes (0.45 ± 0.11 SD) and without red foxes (0.43 ± 0.10) for nests not protected by predator exclosures, but predation rates were higher for exclosed nests at sites without red foxes (0.20 ± 0.08) than sites with red foxes (0.06 ± 0.04). We found evidence that red fox habitat use decreased as the distance to the nearest primary dune increased and that habitat use remained constant throughout the course of the nesting season. Our results will lead to more comprehensive recommendations for predation management and restoration to land managers within New Jersey that will simultaneously reduce predation pressures and create suitable habitat to begin recovery within the state.

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