99th ESA Annual Meeting (August 10 -- 15, 2014)

OOS 38

Advancing Knowledge of Alpine and Arctic Treeline Ecotones and Responses to Environmental Change

Treeline research has been advancing rapidly, motivated in part by the need to predict land surface feedbacks to regional and global climate change, water resources in mountain regions, and impacts of environmental change on high latitude and high elevation biodiversity. Upper elevation and northern treeline ecotones are boundary zones between forest and arctic or alpine treeless zones. Although presence of upright trees has defined the treeline per se, treeline is more accurately described as an ecotone structured by complex interactions among vegetation, soils, animals, climate, snow, topography, and disturbance regimes. Responses of this ecotone to environmental change have been observed, but complex lags and feedbacks -- in addition to topographic influences that confound of responses in mountain treelines -- challenge predictions of change. This session brings together diverse perspectives and expertise in treeline research to report recent advances, both in basic understanding of treeline dynamics and in predicting responses of alpine and arctic treelines to environmental change. By including talks from diverse subfields in ecology the session seeks to foster new collaborations and insights that will advance integrative science of the treeline ecotone. A further objective is to bridge the historical divide between arctic and alpine treeline research. The session comprises ten talks on different aspects of treeline research: paleoclimate and paleoecology, tree demography, ecophysiology, modeling treeline, plant-animal interactions, experimental ecology, ecosystem processes, and the role of disturbance in structuring treeline. Speakers represent the international nature of treeline research and work in both arctic and alpine treeline ecotones.