Apparent competition with an invasive plant hastens the extinction of an endangered lupine
Dangremond EM. 2010. Apparent competition with an invasive plant hastens the extinction of an endangered lupine. Ecological Society of America. Ecology
Brief Description: A study of the effects of apparent competition with the invasive grass Ammophila arenaria on the native species Lupinus tidestromii Full Description: Invasive plants may compete with native plants by increasing the pressure of native consumers, a mechanism known as “apparent competition.” Apparent competition can be as strong as or stronger than direct competition, but the role of apparent competition has rarely been examined in biological invasions. We used four years of demographic data and seed-removal experiments to determine if introduced grasses caused elevated levels of seed consumption on native plant species in a coastal dune system in California. We show that the endangered, coastal dune plant Lupinus tidestromii experiences high levels of pre-dispersal seed consumption by the native rodent Ammophila arenaria. We use stage-structured, stochastic population models to project that two of three study populations will decline toward extinction under ambient levels of consumption. For one of these declining populations, a relatively small decrease in consumption pressure should allow for persistence. We show that apparent competition with an invasive species significantly decreases the population growth rate and persistence of a native species. We expect that apparent competition is an important mechanism in other ecosystems because invasive plants often change habitat structure and plant-consumer interactions. Possible implications in the apparent-competition mechanism include selective extinction of species preferred by seed consumers in the presence of an invasive species and biological homogenization of communities toward non-preferred native plant species.
- Type
- Published Report
- Authors
- Dangremond, Emily
- Date of Issue
- 2010-08
- Publisher
- Ecological Society of America
- Units
- GOGA , PORE
- Keywords
- Ammophila arenaria, apparent competition, biotic homogenization, coastal dune ecosystems, life-table response experiment, Lupinus tifestromii, matrix population model, Northern California, Peromyscus maniculatus, Point Reyes National Seashore, population viability analysis, pre-dispersal seed consumption, stochastic population model