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A new understanding of primary succession in high-elevation, deglaciating landscapes

Authors: Steven Schmidt*, , Clifton P Bueno de Mesquita, University of Colorado, Boulder, John L Darcy, University of Colorado, Denver, Kelsey Reider, Murray State University, Joey Knelman, INSTAAR, University of Colorado, Boulder
Topics: Mountain Environments, Sustainability Science, Soils
Keywords: Primary succession, ecological theory, recently de-glaciated landscapes, limiting nutrients, phosphorus
Session Type: Paper
Presentation File: No File Uploaded

Understanding the progression and driving mechanisms behind ecosystem succession following glacial retreat is important for high-mountain areas being impacted by global warming. Unfortunately, most models of ecosystem succession were developed based on research done in coastal, low-elevation ecosystems with relatively mild climates (e.g. coastal Alaska). In contrast, ecological studies of plant and microbial succession in drier high-mountain ecosystems are still quite rare. Here, we present our recent work examining the rate and limiting factors governing ecosystem succession in the rapidly deglaciating Cordillera Vilcanota in southeastern Peru and the Alaska Range in central Alaska. We used field observations of plant and microbial succession along glacial chronosequences, combined with field and microcosm nutrient addition experiments to develop a new understanding of primary succession in high-elevation ecosystems. Perhaps our most important finding is that, contrary to current ecological theory, phosphorus is the nutrient most limiting to the earliest stages of primary succession along glacial chronosequences in the central Andes and central Alaska. We also show that phosphorus addition greatly accelerates the rate of colonization and land stabilization by plants and microbial phototrophs, even at over 5000 meters above sea level in the Andes of southern Peru. These results challenge the idea that nitrogen availability and a severe climate limit the rate of plant and microbial succession in high-elevation ecosystems and should help inform conservation efforts to mitigate the effects of global change on these fragile and threatened landscapes.

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