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Testing the irruptive paradigm of large-herbivore dynamics
1Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia. dave.forsyth@dse.vic.gov.au
Ecology
|April 28, 2006
Summary
Large herbivore populations often exhibit boom-and-bust cycles, known as irruptive dynamics. This study
Area of Science:
- Ecology
- Population Dynamics
- Wildlife Management
Background:
- A common theory suggests large herbivore populations irrupt, crash, then stabilize at carrying capacity.
- Empirical evidence supporting this dominant paradigm has been limited and largely anecdotal.
Purpose of the Study:
- To develop and evaluate mathematical models describing irruptive population dynamics in large herbivores.
- To test which model best fits empirical data from ungulate populations.
Main Methods:
- Developed two novel mathematical models (Caughley and Leopold) for irruptive dynamics.
- Compared these with existing models (theta-logistic, delayed-logistic).
- Applied models to analyze population data from seven ungulate populations (five introduced, two post-harvesting).
Main Results:
- Six of the seven ungulate populations exhibited irruptive dynamics.
- The Leopold, Caughley, and delayed-logistic models best described these irruptive patterns.
- One population did not show irruptive dynamics, fitting the theta-logistic model.
Conclusions:
- Findings support the widespread occurrence of irruptive dynamics in large herbivore populations.
- Recommends incorporating irruptive models for more accurate ecological studies and wildlife management.
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