Missing Mammals on Great Basin Mountains: Holocene Extinctions and Inadequate Knowledge

The discontinuous distribution of boreal mammals across Great Basin mountains has provided a significant body of data for the analysis of biogeographic patterns in isolated populations of small mammals. Such use assumes that species unreported from particular ranges do not, in fact, occur there. Data from the Roberts and Diamond mountains (central Nevada) demonstrate that this assumption is incorrect. The new distributional records from these ranges further decrease the slope of the log species—log area relationship for Great Basin boreal mammals, but increase the nestedness of the montane faunas involved. These data underscore the need for more-thorough assessments of the mammalian faunas of Great Basin mountains, but they also suggest that extinction of boreal mammals on these mountains is even more predictable than has appeared in the past.