The loss of biodiversity associated with the intensification of agriculture has been well documented for several wildlife species but remains poorly understood for bees, which provide pollination to many agricultural crops. Most pollinator-dependent crops rely heavily on managed honey bees (Apis mellifera L.) for pollination. Four thousand other species of bees native to North America may provide pollination insurance in the event of honey bee losses, but without a clear understanding of how agricultural intensification affects wild bees, habitat conservation measures aimed at protecting them may be futile. In the second part of this study, I evaluated six metrics of agricultural intensification with respect to native bee diversity and abundance in Massachusetts cranberry bogs, including honey bee competition, bog management type (i.e. organic versus conventional), distance from epicenter of cranberry-growing region, toxicity of insecticide program, susceptibility of reproductive bees to insecticide, and surrounding land use. I found a clear association between reduced native bee diversity and abundance and the effects of increased agricultural intensification of the landscape. Recognition that native bee communities in North America are diminishing as a consequence of agricultural intensification may help to unify a movement toward improved conservation management.

Experiments investigated the effect of water temperature on dodder seed germination. Studies, ran twice, submerged dodder seed in water for 0 to 48 hr at 10, 15, and 20 C in one experiment (simulating spring water temperatures) and 0 to 48 hr at 15, 20, and 25 C in a separate experiment (simulating summer water temperatures). In Run 1, the effect of temperature on percent seed germination varied by flood duration; and by temperature alone in Run 2. Percent seed germination however, always fell within normal ranges (35-59%), indicating that flooding may not impact seed germination.

Two 1-yr field studies were conducted to evaluate the use of short-term floods (24 to 48 hr) for managing dodder in cranberries. Two scenarios were simulated: cranberry beds with no emergent weed populations (cranberries alone) and cranberries with emergent weed populations (cranberries with additional host). There were three flood durations (0, 24, and 48 hr) and four flood initiations (1 to 4 wk after first seedling emergence). In 2006, mean percent germination from seeds incubated in Petri dishes was lower for seeds submerged 3 and 4 wk after first emergence (AFE) for the 48-hr flood durations. In 2007, mean percent germination for seeds submerged for 24 and 48-hr decreased for floods initiated at 4 wk AFE. Flooding 4 wk AFE resulted in lowest mean attachment ratings in both years and lowest mean dodder biomass on cranberry in the 2007 cranberry and tomato study, suggesting later flood initiation may provide better dodder management.