Changing fish biodiversity: Predicting the loss of cyprinid biodiversity due to global climate change

Substantial changes in the patterns of global temperature and precipitation are predicted to occur over the next century. Changes in the thermal habitat will alter the thermal boundaries that currently limit the distribution of many species. Species such as smallmouth bass Micropterus dolomieu are currently limited in their northern distribution by temperature-related effects as the length of the growing season determines population viability through overwinter survival of the young-of-the-year. Using a climate change scenario, we estimate the additional area and number of lakes within Ontario that will provide suitable thermal habitat sufficient for their viability. Smallmouth bass are known to have strong negative impacts on many other aquatic species. We estimate their impact, in extirpating four cyprinid species, northern redbelly dace Phoxinus eos, finescale dace Phoxinus neogaeus, fathead minnow Pimephales promelas, and pearl dace Margariscus margarita, in Ontario. We estimate that in excess of 25,000 populations of these species may be lost and discuss the relative sources of errors within our modeling approach.