Our research is focused on understanding forces that shape the development of biological communities and associated ecosystems on landscapes left barren by Mount St. Helen’s 1980 eruption. A surprising and important finding from our work is that the animals that feed on colonizing plants shape the development of plant communities and soils to an extent that has never been previously recognized in primary successional systems. Much of our present work is focused on better understanding this phenomenon and its consequences. We find that insects feeding on alpine lupin (Lupinus lepidus), Sitka willow (Salix sitchensis), black huckleberry (Vaccinium membranaceum), and other keystone and foundational plant colonists influence their population size, spatial spread, and three dimensional architecture of foundation plant species. This result has led to the hypothesis that we should model primary succession as a process of stabilization in the distribution of interaction strengths, and the development of mechanistic models of succession based on nutrient stoichiometry.
Important related findings include 1) Nutrient limitation of arthropods: Persistent spatial differences in herbivory on lupin, in which specialist lepidopteran herbivores are concentrated in low density areas of lupin, can be explained by a paradox of enrichment: At high plant density, food is abundant, but is so deficient in phosphorus that larval performance is severely diminished. Orthopterans also respond spatially to P supply. 2) Nutrient limitation of plants: While Pumice Plain plant communities are nitrogen limited, N-fixation and the N-supply are phosphorus limited; 3) Colonization genetics 50% of black huckleberry colonists are derived from a few relictual individuals embedded within the Pumice Plain, while the remainder are drawn from a variety of sources, with the result that the colonizing population contains more genetic variation than any of the source populations.
Data sets from some of our studies can be found at the Forest Science Data Bank and also here.
Have you seen L. lepidus?
In southern Washington, you’ll find L. lepidus on volcanos, at around 6000-8000 feet in elevation (but only 3000-6000 feet at Mount St. Helens). I have found it growing on Mount Rainier, the Goat Rocks, and Mt. Adams, and nowhere in betweeen. If you find it somewhere west if Mt. Adams and South of Mount Rainier, please contact me!