Speaker: Dr. Ben Gaglioti, University of Alaska Fairbanks & Lamont-Doherty Earth Observatory, Columbia University
In this talk, Dr. Gaglioti will introduce the idea that ecosystems located near glaciers can serve as natural laboratories for global change biology. This is because they have already experienced climate changes that were accentuated by nearby ice-margin fluctuations. Gaglioti will report on results from one of these natural experiments in the old-growth temperate rainforest near La Perouse Glacier in Southeast Alaska.
His team used dendrochronology to observe how tree growth rates responded to a shift from ‘normal’ to accentuated rates of summer temperature change that occurred in the mid-1800s. As trees became more climate stressed, five species that had grown in unison for centuries suddenly shifted to a more diversified growth pattern. This growth shift had several stabilizing effects on the forest ecosystem. Over millennia, tree species and phenotypes may be sorted into forest communities that are capable of absorbing moderate levels of climate stress by activating this diverse portfolio of growth responses. This mechanism of community resilience may be one tool that can help maintain ecosystem services in our more turbulent climate future.