Since 2004, I was invited by Dr. Jorge Ortiz-Zayas and Mr. Carlos Conde from the University of Puerto Rico (UPR) at Rio Piedras to participate on the proposal titled "Hydrological assessment of critical breeding habitats for the endangered Puerto Rican Crestead Toad (PRCT), Bufo lemur". After a first phase funded by the American Association of Zoos and Aquariums (AAZA), we recently obtained funds as part of a larger NSF grant (CREST-CATEC II) to continue long-term studies on hydrology and limnology of a major breeding-pond, and to conduct experiments on the microhabitat and diet preferences and ecosystem role of the tadpoles.

 

The PRCT is an endangered bufonid formerly abundant in the dry forests at the northern and southern karst formations in Puerto Rico, and probably the Virgin Islands. A breeding population is now restricted around a temporary pond located within the Guanica State Forest at the southern karst. Breeding and rearing efforts in captivity were initiated by AAZA's Species Survival Plan in 1984, and tadpoles have been released in yearly basis in additional natural and man-made ponds.

 

Although release efforts are contributing to establish a new breeding population near the Guanica State Forest, additional approaches are in progress. Due to the utmost importance of physical, chemical and biological conditions of ponds for adult breeding and tadpole developement success, AAZA decided to support our studies on the hydrological processes controlling filling and drying, and physico-chemical dynamics of natural and artificial ponds where breeding takes place and does not. Insights have been gained to design and build new concrete artificial ponds and to stop release efforts at two large digged ponds affected by intrusion of saline water tables. In addition, we are modelling mass breeding events relative to intra- and inter-annual variability in rainfall in order to schedule release efforts during rainy seasons and years assuring ponding duration beyond tadpole development time.

 

Institutions participating in the "PRCT Management and Research Expert Group" are AZAA's Species Survival Group through Houston and Disney's zoos, USFWS, PR Department of Natural Resources, Mayaguez Zoo, UPR at Rio Piedras and at Mayaguez, Universidad de Antioquia (Colombia) and several local conservationist NGO".