The Chance Gulch site, 5GN817, is an 8000 year old camp located about 2.5 miles southeast of the town of Gunnison, Colorado. The site is situated within the sagebrush community, though pine and aspen trees are within view. Nine stratigraphic samples were analyzed to determine paleovegetation and pal

The data comprise a long-term study of alpine plant community dynamics in the Gunnison National Forest of Colorado. The data comprise annual census data for all plants (including seedlings) in each of 50 2x2m plots, including information on size, reproduction, life stage, and mortality, with all pla

Variation in the interactions between a nectar-robbing bumblebee and its host plants may have important consequences with respect to the population dynamics of host plants as well as selection on floral and flowering traits.

Plants that experience variation in pollinator visitation rates or fluctuations in weather conditions may be expected to have evolved homeostatic mechanisms that regulate their nectar offerings, thereby providing a more constant reward to the pollinators. A limited degree of such nectar homeostasis

Hybridization in flowering plants is determined in part by the rate at which animal pollinators move between species and by the effectiveness of such movements in transferring pollen. Pollinator behavior can also influence hybrid fitness by determining receipt and export of pollen. We incorporated i

Gynodioecy is a mode of sex expression where male sterlie (hereafter female) plants and hermaphroditic plants coexist within a population. In order for the females to be maintained by natural selection, they must have experienced an increased fitness. Fitness is defined as the ability of genotype or

Resources obtained from the environment are allocated to many plant parts and functions. Resource allocation into defense, growth, and reproduction was examined for Helianthella quinquenervis, the Aspen sunflower, for three field sites over an elevational gtadient. H. quinquenervis has evolved a mut

The Ipomopsis aggregata species complex (Polemoniaceae) includes species pairs that hybridize readily in nature as well as pairs that meet along contact zones with no apparent hybridization. Artificial hybrids can be made between I. aggregata and I. arizonica, yet morphological intermediates between

Two sympatric Delphinium species, D. barbeyi and D. nuttallianum, are ecologically and morphologically similar. However, D. barbeyi has multiple, large inflorescences while D. nuttallianum has a single, small inflorescence. These differences in floral display should result in greater intraplant poll