The biogeographic legacy of an imperilled taxon provides a foundation for assessing lineage diversification, demography and conservation genetics

Climate oscillations that change local environmental conditions often cause species distributions to shift, expand or contract along latitudinal or elevational gradients (Hewitt, 2001, 2004). Whenever species track fluctuating environmental conditions, populations may experience alternating periods of either isolation or connectivity (Hewitt, 1996; Wiens, 2004; Museum of Southwestern Biology and Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA, Department of Fish, Wildlife, and Conservation Ecology, New Mexico State University, Las Cruces, NM 88003, USA, Frey Biological Research, PO Box 294 Radium Springs, NM 88054, USA