Potential future effects of climate change, management, and disturbance on multi-species wildlife habitat suitability and vulnerability in Olympic National Park, WA, USA

Background/Question/Methods

Managers are faced with the daunting task of sustaining habitat for multiple wildlife species in the context of uncertain futures of climate change and wildfire risk. For federally listed threatened and endangered (T&E) wildlife species, the risks of management action or inaction may include reductions in localized habitat area and potential species loss. There may be pronounced tradeoffs in managing for multiple T&E species. We used the mechanistic landscape process model Fire-BGCv2 and habitat suitability index models for multiple T&E wildlife species to assess potential future habitat conditions for at-risk wildlife under various climate change and management scenarios in Olympic National Park (ONP), WA, USA. Our objectives were to: 1) create a methodology for assessing habitat vulnerability and suitability by joining ecosystem process simulation modeling and habitat suitability analysis, and 2) produce a representative set of maps for the T&E wildlife species depicting how climate, disturbance dynamics, and fire and fuels management activities influence wildlife habitat suitability and vulnerability at single species and multiple-species levels. We simulated potential future landscape conditions under two fire management scenarios (suppression/no suppression), two fuels management scenarios (maintain large trees/grow new large trees quickly), and two climate change scenarios (A2/B2) for two ONP landscapes.

Results/Conclusions

Under a hotter, drier climate, fires were more frequent and severe. Species requiring older forest structure had lower vulnerability than species requiring large blocks of contiguous habitat under these conditions. This was because the spatially heterogeneous nature of fire spread and effect resulted in the retention of small patches of the older, closed canopy forest habitat within a matrix of younger forest, and habitat for some species was positively associated with the amount of forest edge. Compared with historical conditions, the recovery of suitable habitat for all species was delayed under both climate change scenarios. This resulted in a decrease of the landscape proportion of suitable habitat. The management scenario that was designed to grow new large trees quickly resulted in higher fire risk than that designed to maintain large trees, because of increased buildup of fuels, and resulted in a moderate decline in the amount of older forest habitat over time. Results demonstrate that management may have unforeseen and unexpected consequences to wildlife habitat in the context of climate change and altered fire regimes. Tradeoffs among species-specific habitat concerns can be assessed even under uncertain future climate conditions, and can contribute to the development of comprehensive conservation-oriented management plans.