Guano mining changed the cave environments by lowering their humidity, which possibly made them inhospitable to bat colonies.Baudunette, R. V., Wells, R. T., Sanderson, K. J., & Clark, B. (1994). Microclimatic conditions in maternity caves of the bent-wing bat, Miniopterus schreibersii: an attempted restoration of a former maternity site. Wildlife Research, 21(6), 607-619.
