UCB Moorea Class: Biology and Geomorphology of Tropical Islands

The island of Moorea, Society Islands (French Polynesia) provides a unique opportunity to examine patterns of spider diversity on a small high volcanic island. I collected spiders at a range of elevations (0~900m) and habitats (disturbed coastal, streamside, mid-elevation ridges and high mountains). This allowed me to map distributions and look at differences in spider assemblages. Specimens were identified to family level. I found a total of 30 different morphospecies. A total of 1738 spiders were collected (using sweep netting and active searching) represented by 12 families, 16 determined genera and 12 determined species. My survey revealed that streamside and coastal communities had the greatest overall biodiversity while having the lowest native diversity. Mid-elevation ridges and high mountains had lower overall diversity but higher native biodiversity. Differences in overall diversity may be due to variation in structural differences between these habitats. In the future, more extensive surveys of the spider fauna need to be done to determine whether structural diversity, elevation or vegetation type is most responsible for different distributions of biodiversity. The spider fauna of Moorea is dominated by nonnative species. As anthropomorphic disturbances on the environment increase, more efforts should be directed towards conservation of mid-elevation ridge and high mountain sites which possess more native species.