Climate Change and Biodiversity

As the fall semester comes to a close, I thought I would share one of the most striking messages we have experienced so far. In our Marine Ecology class we have been discussing the importance of biodiversity and the interactions that structure marine ecosystems.

Some researchers believe that we are currently in the 6th Mass Extinction in the history of the planet. Extinction rates across a broad range of taxa are increasing, and some predictions of global climate change may push these rates even higher (1). Itis predicted that this mass extinction may have extinction rates greater thanany event in the history of the planet. That’s right, bigger than even the extinction event responsible for wiping out the dinosaurs.

Courtesy of Matt Bracken 2011

This loss of so manyspecies may have a greater impact on ecosystems than the removal of any single species. There are many marine examples demonstrating that diversity can enhance the growth or fitness of organisms compared to when those same organisms are found in isolation. For example, studies have shown that intertidal algal assemblagesare more productive than predicted by the component algae species (2). Many marine systems also rely on subsidies such as nitrogen from marine bird guano to fertilize intertidal algae (3). These subsidies can play large roles in some coastal systems. If multiple species are lost and diversity decreases theremaining species may not be able to be able to “take up the slack.”

I don’t believe thatthis is a “Doom’s Day” message but rather a resounding call to reexamine the effects of global climate change in light of declining global biodiversity. The climate is changing, and regardless of whether or not you believe it is anthropogenic (caused by humans), the world we live in is changing. I hope that we have the tools and the care to both make our lives comfortable and maintaining the species diversity that we rely on.

1 - Pimm SL, GJ Russell, JL Gittleman, TM Brooks. 1995. The Future of Biodiversity. Science 269:347-350.

2 - Stachowitz JJ, M Graham, ME Bracken, AI Szoboszlai. 2008. Diversity enhances cover and stability of seaweed assemblages: The role of heterogeneity and time. Ecology 89:3008-3019.

3 - Wainright SC, JC Haney, C Kerr, AN Golovkin, MV Flint. 1998. Ultiziation of nitrogen derived from seabird guano by terrestrial and marine plants at St. Paul, Pribilof Islands, Bering Sea, Alaska. Marine Biology 131:63-71.