Understanding mechanisms by which species become locally extinct can help predict future species declines. Identifying trait differences between locally extinct and present species can help identify the characteristics associated with species losses. Granivory (seed predation) can be an important biotic factor via consumer preferences and may be higher in rare species than common congeners. Granivory has also been shown to limit population growth and may therefore influence species declines. However, we do not know how granivory may have influenced local extinction events. We set out 150 seed trays containing 5 confamilal pairs of locally extinct and present native prairie species once found in Kalamazoo County, MI, in a restored prairie and calculated the proportion of seeds removed by arthropods and small mammals. We ask: (1) Does seed size differ between locally extinct and present species? (2) Does granivory differ with seed size? (3) Does granivory differ between locally extinct and present species?
Results/Conclusions
Granivory was higher on present species’ seeds (χ2=11.03, p<0.001), suggesting that seed predators may prefer more common species. While extinct species had larger seeds than present species (F=7.68, p=0.006), granivory was independent of seed size (F=0.52, p=0.5). This study helps determine if granivory influenced local extinction events and how contemporary prairie species might be affected by seed predation.