An article and video on CNN came out the other day discussing the work of Bryan Pijanowski in recording the acoustic environment in the jungles of Costa Rica, and how Pijanowski is concerned about the silencing of these ecosystems over time and what they might mean for the health of ecosystems and the possible extinction of species. Frogs are a great indicator species due to their sensitivity to environmental issues, and unfortunately it seems that frogs are getting a lot quieter in the areas studied over time, indicating that there are issues for the health of the ecosystems.
You can watch the video and read the whole article at:
http://edition.cnn.com/2016/12/11/world/vanishing-sutter-amphibian-extinction/index.html
I mentioned a similar issue/article in a previous blog post too: