Though rarely experimentally tested, biotic interactions have long been hypothesized to limit low-elevation range boundaries of species. We tested the effects of herbivory on three alpine-restricted plant species by transplanting plants below (novel), at the edge (limit), or in the center (core) of

Bumble bee queens initiate nests solitarily and transition to living socially once they successfully rear their first cohort of offspring. Bumble bees are disproportionately important for early season pollination, and many populations are experiencing dramatic declines. In this system, the onset of

One possible effect of climate change is the generation of a mismatch in the seasonal timing of interacting organisms, owing to species-specific shifts in phenology. Despite concerns that plants and pollinators might be at risk of such decoupling, there have been few attempts to test this hypothesis

Phenological advancements driven by climate change are especially pronounced at higher latitudes, so that migrants from lower latitudes may increasingly arrive at breeding grounds after the appearance of seasonal resources. To explore this possibility, we compared dates of first arrival of Broad-tai

Abstract: Residential development is occurring at unprecedented rates in the Rocky Mountain region of the United States, with unknown ecological consequences. We conducted our research in exurban development in Pitkin County, Colorado, between May and June in 1998 and 1999. Unlike suburban developme

Broad‐tailed and rufous hummingbirds avoid plants and flowers that have recently been visited by nectar‐robbing bees. However, the cues the hummingbirds use to make such choices are not known. To determine the proximate cues hummingbirds use to avoid visiting nectar‐robbed plants, I conducted multip

Judith M. Daniels, Dr. Scottie Willey. Rocky Mountain Biological Laboratory. 1999.