PARENT SESSION
Oral Session #31: Plant Reproductive Ecology, Pollination, and Dispersal. Presiding: J. Karron.
Tuesday, August 7, 2001. 1:00 PM to 5:00 PM. Hall of Ideas L&M.
Effects of habitat fragmentation on bumblebee movement in a Massachusetts conservation area.
Bhattacharya, Madhumita1, Primack, Richard1, Gerwein, Joel2, 1 2
ABSTRACT- We examined how habitat fragmentation by roads and railroads affects the movement of marked bumblebees between plant patches of sweet pepperbush (Clethra alnifolia L. f.) and buttonbush (Cephalanthus occidentalis L.) in a temperate conservation area in metropolitan Boston, Massachusetts. Bumblebees are known to be important pollinators for many temperate plants and capable of flying great distances. Bumblebees showed high site fidelity to a single patch over many days and only rarely crossed roads or railroads. When bees were captured and moved across a road they flew back to their original site, some within 20 minutes of their release. When all the flowers were removed from one Clethra patch, most bees moved to other Clethra populations on the same side of the road and only one bee crossed a nearby road. The results show that while bumblebees have the ability to cross a road and railroad, these human structures may restrict bumblebee movement and act to fragment plant populations. Moreover, marked bees were almost never observed to move between populations unless they were displaced by us, or forced to seek additional forage sites. Thus habitat fragmentation by roads and railroads may hamper pollinator movement and gene flow among plant populations, with implications for outcrossing and seed production.
KEY WORDS: bumblebees, Clethra alnifolia, habitat fragmentation, pollination