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Published on: March 12, 2013
Density-dependent recruitment in grassland small mammals
1Natural History Museum/Biodiversity Research Center, Department of Ecology and Evolutionary Biology, Dyche Hall, 1345 Jayhawk Boulevard, University of Kansas, Lawrence, KS 66045-7561, USA. reedaw@umkc.edu
The Journal of Animal Ecology
|November 28, 2007
Summary
Population density negatively impacts small mammal recruitment, affecting survival or immigration. This study highlights recruitment as a key density-dependent factor in rodent population dynamics.
Area of Science:
- Ecology
- Population Biology
- Mammalogy
Background:
- Density dependence significantly influences population dynamics in many small mammal species.
- Understanding which vital rates are most affected by density is crucial for population regulation.
Purpose of the Study:
- To investigate the relationships between population density and vital rates (proportion of pregnant females, fecundity, recruitment) in five rodent species.
- To identify the primary mechanisms of density dependence in grassland small mammals.
Main Methods:
- Utilized a long-term dataset from five rodent species in Kansas, USA.
- Estimated proportion of pregnant females from field data.
- Calculated per capita fecundity using survival, pregnancy rates, and literature-based litter sizes.
- Employed reverse capture-recapture histories to estimate per capita recruitment.
Main Results:
- Proportion of pregnant females generally increased with density.
- Fecundity showed a negative relationship with density only in cotton rats (Sigmodon hispidus).
- Recruitment exhibited a negative density dependence across all five species, most strongly in prairie voles (Microtus ochrogaster) and cotton rats.
Conclusions:
- Density-dependent recruitment is a significant factor in grassland small mammal populations.
- Negative impacts on recruitment likely occur via reduced immigration or nestling survival.
- Future density dependence models should incorporate immigration alongside survival and fecundity.
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