Habitat invasibility is thought to be strongly correlated with the occurrence and intensity of disturbance regimes such as wildfire. This suggests that weed abundance and distribution would grow significantly following fire events, resulting in direct competition with natural plant communities.
Many land managers consider biological control a cost-effective and sustainable long-term strategy for managing invasive species. However, agent impact on target weeds is seldom quantitatively evaluated. We believe that determining the compatibility of biocontrol with episodic wildfire events is an essential question that must be addressed given the cyclical nature of wildfire in our National Forests and the expectation that biocontrol is a viable long-term management strategy.
We will use the interaction of the stem-boring weevil, Mecinus janthinus, with its host weeds, Dalmatian toadflax and yellow or common toadflax as a model to further understand fire effects on biological control agents and targeted invasive plant species.
- Survey target weeds at known biocontrol release sites in burned areas to determine degree to which weeds have been re-colonized by natural enemies.
- Monitor vegetation at study sites in burned and non-burned areas to determine if increase in weed abundance and distribution is correlated with fire events.
- Release agents in burned areas to determine if habitat alteration by fire impacts agent efficacy in host location and attack.
- Monitor vegetation at study sites in burned and non-burned areas to determine if weed fitness and competitiveness is impacted by fire events.
Habitat, demographic and spatial data from agent release sites will be analyzed to determine if fire is a key factor in agent establishment and control efficacy. In addition, analysis will be performed to elucidate potential patterns in insect-plant spatial association as influenced by environmental factors.
- Lolo National Forest
- Helena National Forest, Townsend and Helena Ranger Districts
- Beaverhead-Deerlodge National Forest, Boulder Ranger District
- Gallatin National Forest- Gardiner, Hebgen Lake and Bozeman Ranger Districts
- National Bison Range
- Randolph Homestead - City of Missoula
- BLM land - Canyon Ferry, Melstone, Elkhorns, Hardin
- Private ranches - Boulder, Ovando