1 Introduction Extirpation of small, isolated populations is a major driver of biodiversity loss and species extinction (Ceballos et al. 2015). Habitat loss, fragmentation, and climate change lead to smaller and more isolated populations, which are in turn more vulnerable to extirpation due to classic small population problems (Gilpin and Soulé 1986). For example, inbreeding depression risk increases with decreasing population size and rates of immigration (Keller and Waller 2002).
