Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Tracing impacts of partner abundance in facultative pollination mutualisms: from individuals to populations

Jennifer C. Geib and Candace Galen
Ecology
Vol. 93, No. 7 (July 2012), pp. 1581-1592
Published by: Wiley
Stable URL: http://www.jstor.org/stable/23225224
Page Count: 12
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Tracing impacts of partner abundance in facultative pollination mutualisms: from individuals to populations
Preview not available

Abstract

Partner abundance affects costs and benefits in obligate mutualisms, but its role in facultative partnerships is less clear. We address this gap in a pollination web consisting of two clovers (Trifolium) that differ in specialization on a bumble bee pollinator Bombus balteatus. We examine how pollination niche breadth affects plant responses to pollinator abundance, comparing early-flowering (specialized) and late-flowering (generalized) cohorts of T. parryi and early T. parryi to T. dasyphyllum, a pollination generalist. Co-pollinators disrupt the link between B. balteatus visitation and pollination rate for both clovers. Only for early-flowering T. parryi do visitation, pollination, and seed set increase with density of B. balteatus. Bumble bee density also alters timing of seed germination in T. parryi, with seeds from plants receiving augmented B. balteatus germinating sooner than seeds of open-pollinated counterparts. Benefits saturate at intermediate bumble bee densities. Despite strong effects of B. balteatus density on individual plant fitness components, population models suggest little impact of B. balteatus density on λ in T. parryi or T. dasyphyllum. Findings show that functional redundancy in a pollinator guild mediates host-plant responses to partner density. Unexpected effects of pollinator density on life history schedule have implications for recruitment under pollinator decline.

Page Thumbnails

  • Thumbnail: Page 
1581
    1581
  • Thumbnail: Page 
1582
    1582
  • Thumbnail: Page 
1583
    1583
  • Thumbnail: Page 
1584
    1584
  • Thumbnail: Page 
1585
    1585
  • Thumbnail: Page 
1586
    1586
  • Thumbnail: Page 
1587
    1587
  • Thumbnail: Page 
1588
    1588
  • Thumbnail: Page 
1589
    1589
  • Thumbnail: Page 
1590
    1590
  • Thumbnail: Page 
1591
    1591
  • Thumbnail: Page 
1592
    1592