FWIW the number and variety of birds and animals have increased in the area I grew up and the water is cleaner. It is possible to turn this stuff around.
Sidetracking a bit:
Another two data points: My experience in the Western US mountains and in the southern end of the Cumberland Plateau suggest that in both zones there are more forest mammals, and more wild mammals coexisting with humans in suburban areas; fewer number and varieties of forest birds, but lots of birds that thrive year 'round in human habitat, fewer number and variety of butterflies, fewer frogs, fewer bats. Oh, and fewer reef fish and coral in the Bahamas. More lionfish.
What I wonder is: how significant are the changes I'm seeing in the long-term big-picture? Are populations always this dynamic, or even more dynamic? I think most people tend to aggrandize the importance of events that happen in their own experience, i.e. their own particular time of living, so maybe what I'm perceiving as major trends away from normal are actually quite normal.
I read a book that described the return of life to northern North America after the last great Ice Age. The author asserted that the evolution of life is slower than the change in climate so at any time in the past, life has evolved to the climate of previous years but is not particularly well-suited for the present.
The concern is that the climate change pace and amplitude may get out of range for most life as we know it today to keep up. It's a probable problem sometime in the future, but middle-age people don't have to worry unless they care about future people, animals, or plants.