Reconciling species conservation and ecosystem resilience: Northern spotted owl habitat sustainability in a fire-dependent forest landscape

Maintaining dense forest habitats for the threatened northern spotted owl (NSO) has proven challenging in seasonally dry, fire-dependent landscapes where low-density conditions were historically dominant and are generally more climate- and disturbance-resilient. To better inform the dual, sometimes-conflicting objectives of species conservation and forest resilience, we developed an approach to evaluate NSO habitat sustainability by: (1) quantifying the structure of high suitability habitat (HSH) associated with NSO using two remotely sensed platforms, (2) estimating current and historical HSH abundance, and (3) identifying HSH locations more likely to persist given current and future forest-zone climate projections and increasing risk of severe wildfire. Tall, closed-canopy conditions effectively comprised the key structural features of HSH, providing a means to map habitat through time. Both historical amounts and contemporary spatial patterns of HSH and other forest and non-forest conditions around occupied NSO sites indicated that HSH and forest resilience goals can be congruent at multiple scales. Independent lines of evidence suggest HSH historically composed ∼18–24% of the dry and moist mixed-conifer landscape – considerably lower levels than current management goals in many areas. Projected shifts in climate and severe-fire likelihood suggest substantial spatial and temporal shifts where HSH will be sustainable into the future – mainly in currently moist as well as some cold forest types. These findings can inform the potential convergence and trade-offs of species conservation and disturbance resilience goals across local and regional landscapes, based on the inherent capacity of the landscape to support both goals under projected shifts in climate and wildfire.