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Harvard Forest Symposium Abstract 2015
- Title: Chronic nitrogen pollution alters traits of red oak acorns and changes behavior of rodent seed dispersers
- Primary Author: Michal Bogdziewicz (Adam Mickiewicz University)
- Additional Authors: Elizabeth Crone (Tufts University); Michael Steele (Wilkes University); Rafa Zwolak (Adam Mickiewicz University)
- Abstract:
Aim: The increase of anthropogenic inputs of reactive nitrogen caused by fossil fuel combustion is a recent stress for both terrestrial and aquatic ecosystems worldwide. In our research we studied how chronic nitrogen deposition (> 20 years) alters traits of red oak (Quercus rubra) acorns and how these changes influence dispersal of acorns by rodents.
Main results: Chronic nitrogen deposition decreased tannin levels in red oak acorns while lipid levels were not affected. Moreover, acorn weight was slightly (but significantly) elevated in acorns collected from trees growing at fertilized plot (N acorns). Distance of acorns dispersal by rodents was higher in N acorns than in control acorns. On the other hand, rodents preferred to both remove and eat control rather than N acorns. Finally, proportion of cached acorns that survived till next spring was three times lower in N acorns than in control.
Conclusions: Increased dispersal distance was probably caused by larger size of N acorns. Lower concentration of tannins in N acorns was most likely responsible for reduced removal and caching by rodents. Germination of red oak acorns is extremely low without burial, and in eastern United States acorns are buried mostly by rodents. Therefore, nitrogen deposition might impede natural regeneration of red oaks through its effects on caching behavior of rodents.
- Research Category: Large Experiments and Permanent Plot Studies
Physiological Ecology, Population Dynamics, and Species Interactions
