A recent National Geographic Daily News article led with with this headline:
Short Life of British Mayfly Halved by Climate Change
It goes on to report on a five year study in the River Dove in northern England which found that Ephemera danica - the British version of the Green Drake - has shifted from a two-year to a one-year life cycle.
Researchers suspect warmer stream temperatures are speeding up the instects' metabolism. They (the maflies, not the researchers) are also getting smaller as a result. This creates bigger problems for anglers than having to start tying smaller flies; with a smaller body, the females cannot produce as many eggs, leading to sparser hatches, and threatening the survival of the species itself. There's more bad news in the article. I won't spoil it for you - click the link above to read it.
Thanks to Jack Williams for finding this article.