Rodent seed consumption influences Ozark glade restoration success

Background/Question/Methods

A problem in restoration ecology is that small restorations have fewer plant species and fewer habitat specialists than would be expected based on their area alone.  Many mechanisms could explain this pattern. One possibility is that plant-animal interactions differ on the edge vs. the interior, causing small habitats that have more edges to have stronger plant-consumer interactions. Our research examines the role of seed consumers in Ozark glades, an ecosystem in the Midwestern USA that contains many endemic plant and animal species.  Ozark glades are desert-like outcrops surrounded by forests.  In other open ecosystems, rodent seed predators are known to live and primarily forage in habitat edges; thus plants occuring in the center of large restorations should have a refuge from strong consumer effects.  If rodent seed predators preferentially consume glade specialized species, it might preclude the establishment of these individuals resulting in lower diversity of plant species, particularly in small restorations.  Here we experimentally restored glades of different sizes, asking: (1) Does habitat size influence seed removal rates, (2) Within large habitats, does seed removal rate differ between the edge and interior, and (3) Do rodents prefer to consume glade specialized plant species compared to generalized species?

Results/Conclusions

We find that unlike other studies in open habitats, seed removal rates are similar in restored glades of different sizes, and seed removal rates are higher in the interior of large glades compared to the edge.  Our results are explained by high cover from weedy vegetation in newly restored glades which influences rodent foraging and by our observations that rodents are nesting in the glades as opposed to only the matrix.  Preliminary results show that rodents prefer to consume glade specialized plant species.  Our study has implications for conservation of this unique ecosystem, suggesting that predation might be extremely high in the first few years after the glade is created.  Weed management during these early years (e.g., controlled burning) is critical to create sites for native seeds to establish.