Effects of Heterogeneous and Highly Altered Environments on the Distribution of Imperiled Wildlife Species and Their Habitat

Abstract

One of the greatest challenges facing wildlife conservation is habitat loss. Historical and current human activities coupled with changing climate conditions has directly and indirectly altered habitat available for wildlife and has affected how ecological communities respond to and recover from disturbance. Natural resource management has sought to restore historical functioning ecosystem condition to support wildlife conservation efforts, however, traditional management practices may not be equipped to accommodate future uncertainty associated with the additive and synergistic effects of climate change, disturbance, and human-altered environmental conditions. Our research seeks to understand how changing environmental conditions are affecting wildlife distribution, wildlife habitat, and to assess the effectiveness of current management strategies for supporting wildlife conservation efforts and promoting ecosystem resilience through high intensity disturbance. To address this topic, we researched wildlife occupancy, landscape connectivity, and abiotic and biotic habitat conditions in pre- and post-disturbance landscapes. Our study took place in two localities experiencing recent rapid environmental change associated with human activity and natural disturbances. In freshwater forested wetlands in southwest Florida, USA, we investigated how historical habitat degradation has directly and indirectly impacted the occurrence of the state-threatened Big Cypress fox squirrel (Sciurus niger avicennia). Concurrently, we also assessed how a high intensity hurricane affected the composition and structure of important tree species and the occurrence of four wildlife species sharing habitat with fox squirrels. In southeast Arizona, USA, we investigated how two recent large-scale wildfires have impacted habitat for the federally endangered Mount Graham red squirrel (Tamiasciurus fremonti grahamensis) and examined whether recent pre-fire forest treatments were effective in promoting forest resilience and conserving habitat for Mount Graham red squirrels through wildfire. In southwest Florida, historical and current land use has impacted the effectiveness of protected areas for conserving Big Cypress fox squirrels in forested wetlands. Additionally, historical land use has altered vegetation communities in a way that makes them poorly adapted to extreme disturbances, such as hurricanes. Nevertheless, generalist species were resistant to habitat damage caused by Hurricane Irma in 2017. In southwest Arizona, wildfire has negatively impacted the resilience of vegetation communities and the distribution of habitat for Mount Graham red squirrels. Only one type of forest treatment (fuel reduction) was effective in both promoting forest resilience and conserving habitat for Mount Graham red squirrels through successive fire. Our findings demonstrate the need to incorporate science-based investigation and monitoring into conservation and management to better prepare for and respond to changing disturbance regimes.