Western columbine genetics across HJ Andrews Experimental Forest meadow communities

Woody plant encroachment is diminishing meadow and grassland habitat on a global scale. Increased woody cover influences local conditions such as light/shade environments, local soil characteristics, understory plant community structure, and disturbance regimes. Woody encroachment may also affect landscape-scale biological processes, such as herbaceous plant population structure, through reducing the total cover and continuity of open habitat and eroding mutualistic interactions, such as plant-pollinator interaction networks. A major concern is that habitat fragmentation will have a cascading effect if one or more mutualistic partners is adversely affected. For example, if pollinators are sensitive to disturbance, fragmentation may reduce rates of gene flow among sub-populations of plants, which is predicted to decrease effective population sizes and diminish adaptive potential (i.e. the capacity to respond to selective pressures through the evolution of genetically-based and heritable traits). Alpine meadows of the Cascade Mountains, which support diverse wildflower and pollinator communities, have shrunk dramatically over the last century as a result of forest encroachment. We posited that, as meadows become smaller and less connected, pollinators may abandon the smallest meadows and focus foraging efforts on the largest, most connected meadows with the most resources. This could expedite the decline and ultimate collapse of meadow communities through reducing adaptive potential across sub-populations of plants. We focus on a plant-pollinator interaction between a common, nectar-producing plant, Aquilegia formosa (western columbine), and rufous hummingbird (Selasphorus rufus) pollinators in four montane meadow complexes in the H.J. Andrews experimental forest, Oregon, USA (HJA). Using hummingbird movement data from SA028 (see H.J. Andrews project database), we first ask whether further forest encroachment in the HJA may alter hummingbird movement patterns among me