June 5 2019

12:00 LSB 2320

Janneke Hille Ris Lambers
University of Washington

Forest Community Reassembly with Climate Change


Climate is often assumed to be the dominant force governing species distributions, which leads to the prediction that all species will simply shift their ranges poleward and upward as the planet warms. Locally, plant communities should therefore lose cold-adapted species, while warm-adapted species increase in abundance – a process called thermophilization. However, species differences in climate sensitivity, geographically variable rates in warming, slow generation times and dispersal limitation may add significant complexity to community shifts, complicating predictions of climate-change induced community reassembly. To address this issue, we combine statistical modeling with extensive surveys of plant communities conducted in 1978 and 2015 at Mt. Rainier National Park to assess whether recent warming in the Pacific Northwest has led to thermophilization as expected. We found a strong relationship between community composition and climate, implying an important role of climate in community assembly. We also found that communities have thermophilized in the last 40 years, but significantly less than we would have predicted from rates of recent warming in the Pacific Northwest. Ongoing research suggests that slow demography and limited dispersal constrain rates of community reassembly in response to warming in moist coniferous forests of the Pacific Northwest, rather than climatic microrefugia. Future community shifts in the region may also be slower than expected, unless disturbance regimes change significantly.

HOST: Nathan Kraft
Refreshments will be served at 11:40 a.m.













































































































































































































































































































































































































































































































































































































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