Mantang nag-aadal sa University of the Philippines College of Law, binilog nya an Rights and Natural Resources Center-Kasama sa Kalikasan (LRC) kaiba sinda Supreme Court Associate Justice Marvic Leonen, Dr. Gus Gatmaytan kan Ateneo de Davao University, asin Atty. Nonette Royo na direktor kan International Land and Forest Tenure Facility na nakabase sa Stockholm, Sweden. An LRC organisayon sa karapatan pantawo asin kapalibutan. Sya nagin Direktor kan Research and Development kan LRC puon 1987–91 dangan puon 1993–96.