Complex sentence: In 1995, The Program for the Conservation of Migratory Bats between Mexico and the United States was started by a concerned group of international bat specialists in response to a decline of multiple bat species in Mexico.
Split into simpler sentences: In 1995, The Program for the Conservation of Migratory Bats between Mexico and the United States was started by a concerned group of international bat specialists. This was in response to a decline of a number of bat species in Mexico.