Scientists in Orkney and Shetland think thousands of seabirds failed to breed because global warming killed their food. Because of global climate change, plankton migrate before small fish grow up. Without the fish, sandeel, the birds can’t raise their young. This is one of the things people have speculated about but not proven. If interacting species react differently to rapid climate change, no one is sure what the effects on ecosystems would be. Ecologists have argued about how dependent ecosystems and communities are on the links between species, and this usually looks like an abstruse theoretical debate. The collapse of fish stocks and breeding bird populations could be results of slight shifts in the timing of plankton migrations.
Does that prove that communities are Gleasonian or Clementsian? Does it matter? Clements thought communities developed in stereotyped ways, forming a “superorganism.” Gleason thought animals and plants wound up in the same place and became a community, and that was all a community was. Gallons of ink have been spilled to prove that communities are not super-organisms. None-the-less, communities exhibit structure in some form. Frequently, the removal of one species induces little harm, but sometimes it is catastrophic.
People define keystone species as any species that has that sort of wide ranging impact on a community, but that definition is a bit coarse. A beaver is a keystone species because it changes the environment. Krill are food for everything. Everything depends on plankton, but everything in the prairie depends on grass. Bison are a keystone species, but not grass. I don’t know whether Scottish seabirds will go extinct because plankton migrate faster. Perhaps next year they’ll rebound and everyone will feel silly.
I suspect that if they survive, they’ll do it by a combination of learning and evolution. The ones that migrate earlier will survive better. The ones that eat a wider range of fish will survive, others with broaden their diet. Or the plankton will be back to normal next year. I suspect that the human race will survive climate change by similar means. But is it worth the hassle?
Global climate change won’t have instantaneous, drastic effects. It’ll be the death by a million paper cuts. The problem is that bandages will get to be in short supply by the time anyone notices a problem.