Here’s an essay for you: Going, Going, Gone: Is Animal Migration Disappearing. It’s by David Wilcove and Martin Wikelski and in PLoS Biology. An excerpt:
The question thus arises: Given the panoply of environmental problems we now face, is the fading glory of migration really a significant issue? We would argue that it is. Protecting the abundance of migrants is the key to protecting the ecological importance of migration. As the number of migrants declines, so too do many of the most important ecological properties and services associated with them.
For a more thorough post on the article, check out Grrlscientist‘s blog.