Fast, slow, and adaptive management of habitat modification–invasion interactions: woodland caribou (Rangifer tarandus)

AbstractWoodland caribou (Rangifer tarandus) are declining throughout much of their North American range. In Alberta, industrial development is the major driver for the disturbance to caribou habitat and ecosystem dynamics involving the invasion of other ungulates and predators. Non‐linear predation increases the chances of extirpation. Reversing the decline of an individual herd requires some combination of habitat protection, slow habitat restoration, and control of the faster‐to‐adjust invading ungulates and/or predators. To explain the ecosystem dynamics affecting the decline, and its potential reversal, we develop a mathematical ecological model that incorporates the interactive effects within and between trophic levels, between slow and fast ecosystem variables, and includes non‐linearity. The most effective mix of fast variable controls depends on the relationships among caribou, predators, and their primary prey. Uncertainties create challenges. Even if fast variable controls improve caribou numbers, habitat restoration is necessary to permanently reverse the decline of an individual herd. However, the outcomes of habitat restoration actions are highly uncertain. Uncertainty is addressed at the provincial scale by combining the model with active adaptive management, and the closely related real options approach, which both guarantees against the worst outcome of provincial extirpation and allows further development if restoration activities are successful.