Differential seed predation on trees of northern Michigan.

Abstract

Interactions between plants and animals are extremely important in determining the diversity and composition of any habitat. One of the most important of these interactions is herbivory, and many animals specialize on eating plant seeds because of their relatively high nutritional content. Because seeds of different species contain different amounts of specific nutrients, seed predators should selectively forage for the seeds highest in their limiting nutrients. We found small mammals to be much greater seed predators than ants and other ground dwelling insects on all of our seed species (red oak, red maple, white pine, and red pine), and in all three habitats examined (mixed hardwood glacial moraine, outwash plain, and coniferous pine forest). Our data also indicates that organisms other than ants and rodents are not major predators on these types of seeds. All guilds of predators selectively forage for red and white pine, which we found to provide the greatest proportion of nitrogen and caloric rewards. These data indicate that seed predators in northern Michigan forests are foraging selectively on tree seeds for nutrient content.