Younger Dryas: Effects on Biota
Distribution of species is a large factor because as the onset of a glacial period approaches, biota respond to the changes and therefore may move to a more ideal location. Only where animals are able to follow the food that they consume can they adjust. Plants are able to move, only through seed dispersion, and therefore are at greater risk of extinction during periods of rapid climate change.
The changing climate may render prey more susceptible to predators. There are many species that can't adjust and therefore become easy targets. Also plants are an easy target for the cold because they simply can't bloom in the colder weather.