Climate change is a complex phenomenon with a variety of both abrupt and gradual effects that scientists are trying to uncover. Emerging findings on how diverse ecosystems are responding to climate change, from long-term research conducted under the National Science Foundation’s 40-year-old Long-Term Ecological Research (LTER) program, have now been published. in a series of articles in the journal BioScience.
The LTER Santa Barbara Coastal (SBC) and the LTER Moorea Coral Reef (MCR) at UC Santa Barbara are among 28 sites worldwide where long-term research is yielding important insights.
“Distinguishing the effects of climate change resulting from an increase in the frequency of abrupt events and gradual changes in direction requires a long-term perspective,” said Dan Reed, research biologist at the Marine Science Institute at UC Santa Barbara. and one of the founders of the SBC LTER. . “Research at LTER sites is well placed to study both of these types of climate change phenomena, as it combines long-term observational data to document patterns of spatial and temporal change with experiments, and targeted sampling to identify the biological and physiochemical mechanisms producing the observed changes.”
Information collected from LTER sites includes data on air and water temperature changes, precipitation, sea level, new disturbances, altered primary production, organic and inorganic matter and changes in populations and communities.
Climate change produces different and often unique sets of impacts in different places. The results presented in the BioScience LTER series explore what climate change looks like in four main ecosystems: forests and freshwater, drylands, coastal and ocean.
“Many coastal ecosystems are defined by structuring foundation species, which play a disproportionate role in determining the system’s ecological attributes and their socioeconomic benefits,” Reed said.
At SBC LTER, giant kelp plays an outsized role in the waters just off Santa Barbara, creating undersea forests that are among the most productive ecosystems in the world. Climate change affects this productivity, in the form of rising sea temperatures and storms that can affect the ability of ephemeral algae to become established and attract communities of fish and other sea creatures that inhabit these forests.
At the same time, the MCR LTER, located in French Polynesia, represents one of the most biodiverse ecosystems in the world, thanks to its founding species, reef-building corals. Here, climate change primarily affects water temperature, which increasingly results in the ‘bleaching’ of corals, which starve when heat stress causes them to lose their symbiotic algae. More powerful storms also destroy the habitat of many organisms.
“While severe storms have been a major disturbance to corals throughout their geological history, episodes of massive coral bleaching due to marine heat waves are a recent phenomenon that are increasing in severity and frequency as climate change changes. climate warms the ocean,” said Russ Schmitt, professor. of Ecology in the Department of Ecology, Evolution and Marine Biology at UCSB and Principal Investigator of the MCR LTER Site at the Marine Science Institute at UCSB.
“Our paper examines results from LTER research in kelp forests, coral reefs, tidal marshes, seagrass beds, mangrove forests, and barrier islands that demonstrate how climate change is altering the abundance and performance of coastal founding species to affect the ecological attributes and services of the entire coastal ecosystems,” said Reed. “We discuss how the integrated research approach shared by the LTER sites has been particularly effective to quantify the ability of coastal ecosystems to resist and recover from different forms of climate change and their ability to adapt to long-term climate change.”
Other articles in the series focus on the ecology of drylands, where warming, combined with multidecadal drought cycles, has increased flooding and wildfires, altered resource availability, plant community structure , while severe droughts, wildfires and dust events have exacerbated air pollution. In forests and freshwater areas, the results discuss effects on species composition and ecosystem function. This occurs through complex interactions, cascading effects and feedbacks to the climate system resulting from altered flow and changes in ecosystem processes such as primary production, carbon storage, cycling water and nutrients and community dynamics. In the ocean, climate change is causing relatively large physical changes in pelagic ecosystems, such as increased sea temperatures, altered stratification of surface layers, and decreased sea ice, resulting in varied ecological responses.