Video Surveys of Coral Reefs: Uni- and Multivariate Applications
Aronson RB and Swanson DW. 1997. Video Surveys of Coral Reefs: Uni- and Multivariate Applications. Proc 8th Int Coral Reef Sym. 2:1441-1446
Many survey and monitoring programs rely on repeated samplng of permanently-marked transects or quadrats. However, the repeated measures approach is impractical for sampling more than a few places on a few reefs. Independent sampling provides a useful alternative. In one such sampling program, 10, 25-m long transects are videotaped and then analyzed by point counts, with 50 stop-action frames per transect and 10 random points per frame assessed. The technique provides sufficient power to test univariate and multivariate hypotheses of community composition. In a univariate example, differences between Caribbean reefs as low as 3.6% coral cover were detected at the a=0.05 level. A multivariate example involved testing the hypothesis that community composition at a ship-grounding site was more similar to a natural hardground site than to a spur-and-groove reference site representing the undisturbed condition. Discriminant analyses classified transects from.the ship-grounding site predominantly with the hardground site based on: (1) multivariate percent coral cover, and (2) multivariate percent cover of algal categories. The independent sampling approach has wide applicability, especially where human and financial resources are limited.
- Type
- Journal Article
- Authors
- Aronson, Richard; Swanson, Dione
- Units
- BISC
- Keywords
- Coral Reef, Methods, Research, Research Methods, Transects, videotaping