Pendleton, Burton K. , Meyer, Susan E. .
Factors affecting mast fruiting patterns in the ecotonal shrub Coleogyne ramosissima.
Coleogyne ramosissima (blackbrush) is a long-lived shrub that occupies the ecotone between warm- and cold-winter deserts in the southwestern US. This study was conducted as part of a series of long-term studies designed to understand the life history and regeneration biology of this landscape dominant shrub. We conducted the study from 1990 to 2000 at 12 locations across the range of the species. Data on flowering and seed production were collected in the spring and summer of each year. Climate data were obtained from weather stations nearest to each population. We document mast fruiting in Coleogyne and factors that determine interval length between mast events. Identified factors include previous reproductive effort, amount and timing of precipitation, drought, and late frost. Frequency of mast fruiting increases with increasing elevation and latitude. Reproduction, both in terms of seed numbers and mast events, is lowest at the southern and western edge of the ecotone (Mojave desert), and highest on the northern upper elevational edge (Colorado Plateau). Coleogyne seed is highly palatable to heteromyid rodents, which are the obligate dispersers of this species. Recruitment occurs following a mast event where sufficient seed is produced to satiate the rodents, leaving surplus caches that subsequently germinate. By clarifying how factors associated with mast fruiting affect blackbrush reproduction and establishment at a variety of elevations and precipitation regimes across its range, we can infer how past climate regimes shaped its current distribution and how this species is likely to respond to future climate shifts.
Log in to add this item to your schedule
1 - USDA Forest Service, Rocky Mountain Research Station, 333 Broadway SE, Suite 115, Albuquerque, New Mexico, 87102-3497, USA
2 - USDA Forest Service, Rocky Mountain Research Station, Shrub Sciences Laboratory, 735 N 500 E, Provo, Utah, 84606, USA
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM