|Erica Smith||Haverford '05|
|Rosemary Malfi||Bryn Mawr '07|
|Daniela Miteva||Bryn Mawr '07|
|Amanda Rahi||Bryn Mawr '07|
Effect of landscape change on pollinators and pollination
Pollination and Ecosystem Service
National Fish and Wildlife Foundation. Assessing and Restoring Native Crop Pollinators on Agricultural lands in New Jersey with C. Kremen and R. Winfree (Princeton)
NSF DEB #0516205 Collaborative Research: Community disassembly and ecosystem function: pollination services across agro-natural landscapes with C. Kremen
Pollination is a key ecological function in natural systems. More than 70% of flowering plant species rely on animal pollinators, primarily bees, for sexual reproduction. Native bees also provide a potentially valuable service to humans in the form of crop pollination. If natural habitat is important for maintaining such native populations then pollination service may provide tangible incentives for the preservation of natural habitat. With students and collaborators, I am examining how isolation from natural habitat affects the pollination of crop by native bees. We are also measuring the effect of landscape change on native plant reproduction in remaining semi-natural fragments of woodland. This work explores potential community disassembly and whether it leads to loss of ecological function. This research is one of two major efforts in our lab and has open opportunities for student projects.
Learn more about native bees and crop pollination in Pennsylvania and NJ
|R Malfi collecting pollinator visitation data to tomato. This summer R Malif (BMC '07) began investiagation of bumble bee communities in managed eastern meadows||Flower on a stick. The method of following a bee with an unvisited flower on a long pole allows us to record the numbers of pollen grains deposited on the stigma of a flower by a bee during a single visit. Developed by J Thomson, U Toronto.||Typical mosaic landscape along the Sacramento River composed of patches of remnant riparian forest and wash areas(dark green and gray streaks) surrounded by diverse agricultural fields|
Dynamic pollination in desert communities
Funding: National Science Foundation. DEB# 0418871 Contributions of Specialist pollinators to generalist plants: when do specialists matter? w/ R Minckley and T Roulston
Specialized “coevolutionary interaction” has long been a central tenet to hypotheses on the diversification of flowers. However, recent community studies of pollination interactions show that specialist pollinators commonly share host plants with numerous generalist pollinators, which may dilute their contribution to host plant pollination. Only rudimentary information exists on the importance of specialist pollinators in these interactions, and under what circumstances, if any, they influence floral evolution. In this research our lab group along with RL Minckley (URochester) and TH Roulston (UVa), explore four predictions that could elevate the pollination contributions of specialists over generalists: 1) Specialists are better pollinators than generalists; 2) Specialists will show less seasonal and annual variation in abundance than generalists on the same host; 3) Generalists’ use of host plants will reflect plant species productivity at the community level, and 4) Specialists will be most important to the reproduction of their host when their host is a relatively poor resource provider in the community.
Our study areas are in the
Pollination and restoration
Restoration efforts often focus on target "structural" plants such as trees, shrubs or dominant grasses and on specific animal species. Under such an approach the tacit assumption is that other components of the system and ecological processes will return on the coattails of the active restoration. I have been investigating whether such assumptions are met using a study system along the Sacramento River in California. Students and I have been collecting native bees and recording flower visitation in restored plots and remnants of native riparian forest to determine if pollinator communities and pollination are indeed restored through large scale planting efforts.
Differences in bee life-history are likely to affect whether they reestablish at such sites. Unique characteristics of bee foraging movement and the way they transfer pollen will contribute to their functional role as pollinators and could have significant effects on the persistence and the genetic structure of the restored plant populations as well as those in natural remnants.
One exciting bonus of this research program has been working with farmers,
NGOs, and government agencies to understand their perspective and how their
decisions affect the ecology and management of natural agricultural areas.
Pan-sampling of bees. This method uses colored bowls filled with soapy water to trap bees.
A sample of bees from a pan trap
Pollination Ecology and Pollen Dispersal
In another area of research I am using GMO Brassica
napus (canola) plants to explore pollen transfer
by different insect taxa. I adapted a transgenic
pollen marker within canola that allowed me to track pollen grains from a
specific plant to recipient flowers on other plants. In a simple sense, the
grains from the transgenic plants are blue while those of other wild-type
plants are yellow. This canola system allows detailed analysis of the mechanism
behind pollen dispersal, but do these details apply to diverse natural systems
where plants are visited by a diverse set of pollinators? Based on our
experimental data colleagues and I are modeling pollen dispersal for situations
involving different combinations of pollinators and are exploring on how the
high variability inherent to the dispersal process affects overall patterns of
mating for plants.
Transgenic pollen grains on a leg of the butterfly Pierisrapae.
Bumble bee (Bombus occidentalis) visiting B. napus
Williams, N. M. and C. Kremen (in press). Floral resource distribution among habitats determines productivity of a solitary bee, Osmia lignaria, in a mosaic
agricultural landscape. Ecological Applications.
Ricketts, T., Williams, N. M. and Mayfield, M. M. (2006) Connectivity and ecosystem services: crop pollination in agricultural landscapes In Connectivity
Conservation. Crooks and Muttulingam (eds.)
Larsen, T., Williams, N.M. and Kremen, C. 2005. Extinction order and altered community structure rapidly disrupt ecosystem functioning. Ecology Letters
Kremen, C. Williams,
N. M., Bugg, R. L., Fay, J. P. and Thorp, R. W.
2004. The area requirements of an ecosystem service, crop pollination by
native bee communities in
Williams N. M. 2003. Use of novel pollen species by specialist and generalist solitary bees (Hymenoptera Megachilidae). Oecologia 134: 228-237.
Kremen, C., Williams, N. M. and Thorp, R. W. 2002. Crop pollination from native bees at risk from agricultural intensification. Proc. Nat. Acad. Sci. 99: 16812-16816
Williams N. M. and Tepedino, V. J. 2002. Consistent mixing of near and distant resources in foraging bouts by the solitary mason bee Osmia lignaria. Behav Ecol 14(1): 141-149
Williams, N. M., Minckley, R. L. Silveira, F. 2001. Demonstrating faunal changes in the face of natural variation in bees: the importance of baseline data. Cons. Ecology 5(1): 7. [online] URL: http://www.consecol.org/vol5/iss1/art7.
Harder, L. D., Williams, N. M., Jordan, C. Y, Nelson, W. 2001. The effects of floral design and display on pollinator economics and pollen dispersal. pp.297-317 In: Cognitive Ecology of Pollination, Chittka, L. & Thomson, J. D. (eds.) Cambridge University Press, Cambridge.
Williams, N. M. and Thomson, J. D. 2001. Pollinator quality in native bees and honey bees: comparing pollen removal and deposition on Phacelia tanacetifolia. In: Whence the pollinators of the future, Strickler and Cane (eds) Symp. Proceed. Entomol. Soc. Amer..
Williams, N. M. and Goodell, K. 2000. The association of nesting material and mandible shape in Osmia (Hymenoptera: Megachilidae): a morphometric analysis. Annals Entomol. Soc. Amer. 93(2):318-325.
Chittka, L., Williams, N. M., Rassmussen, H. and Thomson, J. D. 1999. Navigation without vision: bumblebee orientation in complete darkness. Proc. R. Soc. Lond. B. 226: 45-50.
Williams, N. M. and Thomson, J. D. 1998. Trapline foraging by bumble bees III. Temporal patterns of visitation and foraging success at single plants. Behav. Ecology 9 (6): 612-621.
Waser, N. M., Chittka, L., Price, M. V., Williams, N. M., Ollerton, J. 1996. Generalization in pollination systems and why it matters. Ecology 77(4): 1043-1060.
Kremen, C., Williams, N. M.
Kremen, C., Williams, N. M.et al. Impact of land use change on pollinators: developing a conceptual framework for mobile-agent based ecosystem services
( Submitted Ecology Letters August 2006)
Submitted Ecology Letters August 2006)
Williams, N. M., Richards, S. and Harder L. D. The importance of variation in pollen deposition for understanding plant mating patterns.
Williams, N. M. and Harder L. D. Comparison of pollen dispersal patterns by co-visiting pollinators