Small mammals in the northern Flint Hills prairie: Overwinter changes in abundance

TitleSmall mammals in the northern Flint Hills prairie: Overwinter changes in abundance
Publication TypeJournal Article
Year of Publication2018
AuthorsKaufman, DW, Kaufman, GA
JournalTransactions of the Kansas Academy of Science
Pagination297 - 315
Accession NumberKNZ001991
KeywordsAnnual variation, deer mice, Konza Prairie, Long-term ecological research, native tallgrass prairie, overwinter decline, relative abundance, rodents, Seasonal variation, shrews, site variation

It is assumed that abundance of individual species of rodents and shrews in temperate regions decrease overwinter owing to winter mortality and cessation of reproduction. We wanted to examine this autumn versus spring pattern by using a 32-year long-term dataset from seven treatment sites on Konza Prairie Biological Station near Manhattan, Kansas, although we could not examine mortality or reproduction directly. We specifically wanted to determine first whether long-term patterns for species of small mammals showed that abundance decreased from autumn to spring and secondarily whether these patterns held among years and different habitat types. The decrease from autumn to spring was supported but, for individual species, varied from a 4% decrease to a 99–100% decrease. For the ten species that had at least one capture in either autumn or spring, the years in which autumn abundance was greater than that in spring varied among species; the range was from 44% of years for thirteen-lined ground squirrels (Ictidomys tridecemlineatus) to 100% for Elliot's short-tailed shrew (Blarina hylophaga). Likewise, patterns of decrease varied considerably among habitat types when spring abundance was compared as a percent of autumn abundance in the six most common species in seven research treatments. For example, spring abundance of deer mice (Peromyscus maniculatus), the most common small mammal, was only 52–54% of that in autumn for ungrazed sites that were burned annually, burned every 4 years or burned infrequently, whereas it was 105–130% of autumn abundance in bison-grazed sites that were burned annually or burned infrequently. Among the seven research treatments, the two least variable species decreasing in abundance from autumn to spring were Elliot's short-tailed shrews (spring populations were only 0–2% of those in autumn) and hispid cotton rats (Sigmodon hispidus; spring populations only 0–15% of those in autumn). Given the length of the study period, the high proportion of years that numbers of the common rodents increased from autumn to spring within the highly diverse mosaic of prairie studied suggests that a significant level of reproduction can occur between autumn and spring in many years, a life history trait that requires more study, especially in light of global climate change.