Timber harvest and wildfires drive long-term habitat dynamics for an arboreal rodent

Abstract

Animals dependent on old, closed-canopy forests may be particularly sensitive to forest disturbances, such as timber harvest and high-severity fires, that may take centuries to recover from. Tracking habitat trends can provide broader context to conservation decisions, including the role of forest disturbance type. We assessed habitat dynamics across the range of the red tree vole (Arborimus longicaudus), a canopy-obligate rodent with low-mobility that typically occurs in old forests. We developed and applied a red tree vole habitat model to imagery data each year across 37 years (1986–2022). We quantified changes in habitat across four regions that differed by land ownership and dominant disturbance type. Overall, habitat declined 18 % since implementation of a major conservation initiative (1994–2022). Habitat change was highest in the northern coast (65 %) where timber harvest was the most common disturbance. Within interior regions, several large wildfires in the previous two decades correlated with a 15 % decline of habitat on federal lands, particularly at the northern range periphery where tree voles were already scarce due to historic disturbances. Recruitment of old forest and subsequent recolonization by red tree voles and other low mobility species after high-severity disturbance can take centuries whereas old forest loss can happen rapidly. Given their strong association with old forest, scarcity within historic disturbance footprints, and relatively limited geographic range, we anticipate red tree voles will remain a species of conservation concern.