Time: Wednesday, March 21, noon Eastern
Titles and Speakers:
Talk 1: Mary Rowland, Research Wildlife Biologist, U.S. Forest Service; and Dr. Sandra DeBano, Associate Professor – Invertebrate Ecology, Oregon State University: Native Bees and Large Mammals: Vertebrate – Invertebrate Interactions in Riparian Natural Areas
Land managers have increased efforts to better understand how natural areas can be managed to enhance native pollinators; however, pollinator management must be balanced with other uses such as livestock grazing and wildlife habitat. Yet little attention has focused on how grazing mammals, especially native ungulates, interact with pollinators. As part of a larger, collaborative project evaluating ungulate grazing management and riparian restoration at the Starkey Experimental Forest and Range (Starkey) in northeast Oregon, we examined how large mammals may influence native bees through dietary overlap. We sampled native bees and floral resources from spring to fall in 2014-2016 along a 14-km reach of Meadow Creek within Starkey to 1) document which flowering species are most commonly visited by native bees, and 2) quantify how herbivory by deer and elk influences flowering plant communities. Half of the 12 sampling sites were excluded from grazing. We recorded >150 species of flowering forbs and shrubs and >900 bee visitors of >80 species. Flowering stems were generally more abundant in ungrazed vs. grazed sites; however, patterns were highly variable in time and space and across species. For some plants frequently visited by bees and also in elk diets (e.g., Potentilla gracilis), we found higher flower abundance in ungrazed sites. We discuss management implications relative to seasonal habitat use and dietary preferences of ungulates and variation in bee phenology, and conclude with guidance about timing and intensity of ungulate grazing when managing for multiple conservation objectives in grazed sites, especially in riparian areas.
Talk 2: Thomas Kaye, Executive Director and Senior Ecologist at the Institute for Applied Ecology: Partnering with Pollinators: Prairie Restoration to Support Diverse Pollinating Insects
Insects are important pollinators of many plants, from agriculturally significant species to plants in natural areas. Pollinators and plants depend on one another for completion of their life cycles and together they serve significant ecosystem functions. Restoration and management of prairie habitat in the Pacific Northwest provides an opportunity to improve conditions for many pollinators, and land managers can provide better conditions for these insects by providing for basic life-history needs of major insect groups, especially through providing a diversity of plants that provide nectar and pollen as food, as well as nesting habitats. Research on habitat restoration in this region at multiple upland and wetland sites shows that flowering plant diversity can be increased by combinations of management treatments that include seeding with native plants after burning and herbicide applications. Although these treatments can improve conditions for food plants of insects, they can also harm or kill them, so it may be important to apply such treatments over portions of managed landscapes rather than all at once across managed sites. Strategies that combine improvements in plant diversity and overlapping bloom periods throughout the growing season with habitat features such as bare ground, availability of dead hollow or pithy stems of woody plants, and leafy materials, can optimize food and nesting conditions for multiple species of pollinating insects while achieving many other restoration goals.