NSF grant – DEB10-50694. 60 months, 1/1/2011 to 12/31/2020. LTREB: Ecosystem response to climate change: role of ecological subsidies and species interactions.
This LTREB grant supports research on factors underlying among-site variation in community structure along the Oregon coast, with the goal of developing a long-term suite of studies for detection of the ecological impacts of climate change. My focus was particularly on the role of species interactions (predation, competition for space, facilitation), disturbance, and inputs of ecological subsidies (phytoplankton, propagules) on spatial domination by sessile invertebrates and macrophytes. The basic questions were “what are the mechanisms underlying the higher abundance of macrophytes and lower abundance of sessile invertebrates at some rocky intertidal sites vs. the opposite pattern at other sites?” and “what are the likely impacts of climate change on these mechanisms and patterns?” The proposal grew out of existing long-term data sets on community structure, species interactions, environmental conditions (temperature, upwelling) and the inputs of propagules, food for filter-feeding invertebrates (phytoplankton), and nutrients across 10 sites along the Oregon coast, and prior analyses showing impacts of climate variability on prey recruitment, phytoplankton abundance, and mussel growth
Ecosystem response to climate change – role of ecological subsidies and species interactions
Q1: What biotic and environmental mechanisms underlie mussel abundance responses among Oregon intertidal sites and zones?
Q2: More generally, how will this and other key community components respond to ongoing increases in upwelling, temperature, and wave forces?
Q3: How do species interactions respond to and interact with environmental change?
Hypotheses, as modified from those in the 2010 LTREB proposal, are:
H1: Abundance of mussels and overall community structure vary in response to climatic variability.
H2: Differences in species dominance among zones and regions are attributable to environmentally-driven spatial and temporal variability in ecological subsidies, physical disturbance, and species interactions.
H3: Alternatively, persistent sparsity of sessile invertebrates at CF sites results from pre-emptive competition from macrophytes. Persistent dominance of macrophytes at CF sites results from localized recruitment and high growth from high nutrient levels delivered by strong and increasing upwelling, so macrophyte dominance should persist, and macrophytes should continue to exclude sessile invertebrates.