IntegratedMagnetic and Global Positioning SatelliteMap- ping of the Firestone Reserve, Costa Rica

High-resolution topographic mapping of the Firestone Reserve, southwestern Costa Rica, has pre-sented a number of challenges resulting from the poor-to-non-existent GPS satellite reception in steep canyons and under tropical rainforest canopy. We have successfully employed magnetic survey tech-niques and data reduction software developed for cave mapping, integrated with sub-meter accuracy, GPS-derived reference points in those areas where topography permits GPS reception. The resulting topographic map is based on an x-y-z coordinate array averaging 284 data triplets per hectare and pro-viding the level of resolution necessary to support microhabitat-level ecological studies