Abstract Although population management measures have been used to avoid continued extirpation of caribou ( Rangifer tarandus caribou ) in some areas of British Columbia (BC), protection and restoration of their range remain challenging. Effectiveness of mitigations associated with continued loss of habitat through industrial resource extraction is unproven, making assessment and regulation of applications for large industrial projects unreliable. Using a longitudinal data sample and a spatial control, we quantified the potential effects of open‐pit coal mining by comparing the behavior and demographics of caribou groups in areas with and without mining within the Quintette herd of the Central Group of Southern Mountain Caribou in BC. The Treatment (with mining) and Control (no mining) areas are in separate units of High Elevation Winter Range (HEWR), a habitat critical for sustaining these caribou. The Treatment and Control areas were sufficiently separated that groups of caribou used the areas discretely. We characterized a cascade of ecological events for Treatment caribou beginning with maladaptive behavior responses leading to negative demographic outcomes that were not observed for Control caribou. After the start of mining, Treatment caribou spent proportionately more time at low elevations away from HEWR, resulting in larger areas of use during winter in habitat with greater levels of anthropogenic disturbance. Greater risk of predation was assumed to occur from the disturbance‐mediated apparent competition operating within the more general herd area and, consistent with that assumption, Treatment caribou had lower vital rates (adult survival and juvenile recruitment) compared to Control caribou. This outcome indirectly exacerbated the decline in number of caribou using the Treatment area, and that group declined to zero by the end of the study. The multiple lines of evidence from behavioral responses to demographic effects suggest that critical habitat for these caribou becomes either compromised or irreparably harmed by mining disturbance.
McNay et al. (Fri,) studied this question.