Aerial surveys of caiman, marsh deer and pampas deer in the Pantanal Wetland of Brazil

The yacare caiman (Caiman c. yacare) was illegally hunted in the Pantanal d uring the 1970s and 1980s at levels that may have reached one million skins per year. The possibility that yacare caiman had been over-exploited gener ated pressure for a monitoring programme for caiman populations. The marsh deer (Blastocerus dichotomus) and pampas deer (Ozotocerus bezoarticus) are listed as endangered in Brazil and need the protection of effective managem ent programmes. Ground surveys are difficult for the extensive and inaccess ible Pantanal Wetland, south-western Brazil, but aerial surveys provided in formation that allowed re-evaluation of conservation priorities. Caiman and marsh deer have larger populations than was believed. Preliminary data ind icates that the pampas deer density decreased at a rate of about 30% per ye ar from 1991 to 1993. This indicates the need for detailed ground-level stu dies for the pampas deer population in the Pantanal. We recommend a long te rm monitoring program using standardized counting procedures for wildlife p opulations in the Pantanal. (C) 2000 Elsevier Science Ltd. All rights reser ved.