Renner, Maralyn A. .
Effects of disturbance on the persistence of Howell.
Howell's montia (Montia howellii Wats.), a member of the Portulacaceae, was thought to be extirpated from California prior to its re-discovery by Clare Golec in 1999 on logging roads on private timberland in Humboldt County, California. This tiny, succulent, winter-germinating annual is specific to lightly disturbed sites with compacted mesic soils. Since its rediscovery, it has been located in increasing numbers each year that surveys have been conducted. Two general types of mitigation have been employed, 1) complete protection of the plant groups by avoidance and 2) several variations of disturbance. The disturbance methods were developed through consultation with the California Department of Fish and Game, and modeled after measures in use by the Bureau of Land Management in Oregon. These included light road grading during the Howell's montia dormant season (summer and fall), soil removal and replacement, and protection of the soil/seed bank using geotextile fabric. Currently, our mitigation method of choice is the prevention of road use during the Howell's montia growing season (January to mid-June) with light road grading during the dormant season. Groups of populations have been monitored for 3, 4, and 5 years (each season since their discovery). The purpose of monitoring was to provide data on the environmental parameters that most favor the speciesí persistence and to determine itís response to disturbance versus non-disturbance regimes. Monitoring will continue until 2007. Our preliminary results indicate that the preferred environmental parameters are mesic compacted soils and reduced competition from other plants. Mitigation that avoided impacts to the sites, thus allowing competing vegetation to invade, resulted in fewer plants in following years. Without factors that maintain open canopy and compacted soils, competing vegetation will apparently crowd out the Howell's montia populations. Seasonal road use maintains these favorable conditions.
1 - PALCO, Science Department, P. O. Box 712, 125 Main St., Scotia, California, 95565, USA
Presentation Type: Paper
Location: Wasatch (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 9:45 AM