Species: Mimulus clivicola

Most biological/ecological information regarding Mimulus clivicola has been gathered from formal surveys in Idaho and Oregon which were initiated in the late 1980s by the Forest Service through contracts with the Idaho Natural Heritage Program. Also, a germination study was conducted by the University of Montana. <br><br>Mimulus clivicola is a spring-flowering annual that reproduces solely by seeds. Flowering begins in late May or early June and continues to mid-July. It is suspected that pollination is by ants, which may be attracted to the sweet, musky odor of the glandular hairs covering the plant (Lorain 1991). <br><br>Spring precipitation, availability of suitable microhabitat, and certain activities of big game animals seem to have high correlation with the germination and establishment of this species. Availability of spring moisture appears to be a necessary requirement. All known populations occur in moist microhabitats such as seepages caused by perched water tables, areas where water channels following rain, or in big-game tracks that hold water. Although these sites may dry out later in the summer, they provide a moist substrate in the spring for seed germination and flowering (Lorain and Moseley 1989; Lorain and Moseley 1990; Lorain 1991; Lorain 1992). Suitable microhabitat, patches of exposed mineral soil, which can result from natural causes such as erosion and the movements of big game or man-caused disturbances such as road-building, appears to be another necessary requirement. The movement of deer and elk not only create areas of exposed mineral soil and tracks that trap water, ideal conditions for germination and growth of the species, but also serve to disperse the seeds. Another aspect of big game activity which may be favoring the establishment of this species, is their grazing of cheatgrass (Bromus tectorum), a very competitive introduced winter annual. This may reduce competition for limited soil moisture on southern slopes, especially during droughty springs, and favor the establishment and growth of Mimulus clivicola (Lorain 1989). <br><br>Research on seed germination and early growth characteristics was conducted by researchers in the Department of Biological Sciences at the University of Montana (Pavek and Mitchell-Olds 1990). Seed germination required three weeks of stratification (moist, cool conditions of 100% humidity at approximately 40 degrees C). There was a high percentage of germination (no actual values given) occurring 12-19 days after the stratification period was complete. First flower buds developed at approximately 5 weeks, just after the second pair of leaves when the plants were only 0.5 inches tall. <br><br>As with many annuals, the number of flowering individuals in any particular growing season is highly correlated with annual weather conditions, in this case the presence of spring moisture, and may not be a good indicator of the long-term viability of the species. Research is needed on the seedbank, seed viability, and population dynamics to help understand the population biology of this species.