I think most animals will adapt to the changes in their surroundings, just like they always have. Hopefully by adapting most species will survive. But there will always be cases where they can no longer adapt and then some will become extinct.
Hi, I actually visited part of the Aral sea last year when I was in Kazakhstan and you literally see ships and boats that got stuck there because the water left and never came back. It was devastating to the local community but also to biodiversity. I think all animals are important and when we lost any part of our ecosystem we are in danger of collapse. For example, think about the bees. Bees have been experiencing mass deaths, especially the bees that pollinate food. This is due to increased presence of a pest, invasive varroa mite; Israeli Acute Paralysis virus and the gut parasite Nosema. Unfortunately, the primary reason is thought to be due to the immune suppressing effects of pesticides used on the plants that bees try to pollinate. Without bees we cannot grow most of the food that we eat on a daily basis, especially fruit and nuts. Bees are essential to our ecosystem and our behaviours (using lots of pesticides) can hurt them.