Edwin A. Hernández-Delgado*

Transcription

1 Long-term Coral Reef Ecological Change Monitoring Program of the Luis Peña Channel Marine Fishery Reserve, Culebra Island, Puerto Rico: I. Status of the coral reef epibenthic communities ( ). Edwin A. Hernández-Delgado* Department of Natural and Environmental Resources Coastal Zone Management Program P.O. Box San Juan, Puerto Rico *Under contract # U.S. Coral Reef Initiative November 27, 2002

2 Table of contents Introduction. 1-3 Pages Methods Study sites. 3-5 Long-term monitoring of coral reef epibenthic communities. 5-8 Multivariate analysis of coral reef communities. 8-9 Indicators of disturbance effects Results Ecological change at CR Multivariate analysis of coral reef communities at CR Indicators of disturbance effects at CR Ecological change at CR Multivariate analysis of coral reef communities at CR Indicators of disturbance effects at CR Discussion Shifts in the structure of coral reef communities Comparison of annual coral decline rates with the wider Caribbean region. The role of algae and cyanobacteria on the coral reef phase shifts. Detection of shifts in community structure by multivariate analyses. Causes of coral decline Caribbean-wide mechanisms or local causes? Local factors and their synergism with regional factors White Plague Type II Low herbivory or selective herbivory: The top down model. Interaction among degrading factors: The down top model. A proposed mechanism of coral reef decline

3 Effects on species diversity: Regional vs. local factors, threshold effects, multiple stable states, and Allee effects. Conclusions Acknowledgments. 117 Cited literature Appendix

4 List of Tables TABLE 1. Summary of the coral community data at CR1 ( ). 13 TABLE 2. Summary of the % of relative coral cover at CR1 ( ). 14 TABLE 3. Friedman 2-way ANOVA for the coral reef community data at 15 CR1. Pages TABLE 4. Friedman 2-way ANOVA for the % of relative coral cover data at CR1. TABLE 5. Exponential regression analysis between the cumulative coral 19 species richness and the cumulative number of replicate transects at CR1. TABLE 6. Exponential regression analysis between the cumulative coral 21 species richness and the cumulative colony abundance at CR1. TABLE 7. Summary of the quadratic regression analysis results between the 33 % of total algal cover and several coral parameters. TABLE 8. Results of the 2-way crossed ANOSIM test for significant 37 differences of the structure of coral reef epibenthic communities at CR1. TABLE 9. Results of the pairwise ANOSIM significance test between 37 years at CR1. TABLE 10. Results of the pairwise ANOSIM significance test between 37 depth zones at CR1. TABLE 11a. Results of the SIMPER analysis of years 1997 vs 1998 at CR1. 39 TABLE 11b. Results of the SIMPER analysis of years 1997 vs 1999 at CR1. 39 TABLE 11c. Results of the SIMPER analysis of years 1997 vs 2001 at CR1. 39 TABLE 11d. Results of the SIMPER analysis of years 1997 vs 2002 at CR1. 39 TABLE 12a. Results of the SIMPER analysis of years 1998 vs 1999 at CR1. 40 TABLE 12b. Results of the SIMPER analysis of years 1998 vs 2001 at CR1. 40

5 TABLE 12c. Results of the SIMPER analysis of years 1998 vs 2002 at CR1. 40 TABLE 13a. Results of the SIMPER analysis of years 1999 vs 2001 at CR1. 41 TABLE 13b. Results of the SIMPER analysis of years 1999 vs 2002 at CR1. 41 TABLE 14. Results of the SIMPER analysis of years 2001 vs 2002 at CR1. 41 TABLE 15. Summary of the Caswell s neutral model V statistics for CR1. 43 TABLE 16. Summary of Pearson correlation matrix for different coral 43 species diversity indices at CR1 through time. TABLE 17. Summary of the coral community data at CR2 ( ). 49 TABLE 18. Summary of the % of relative coral cover at CR2 ( ). 50 TABLE 19. Friedman 2-way ANOVA for the coral reef community data at 51 CR2. TABLE 20. Friedman 2-way ANOVA for the % of relative coral cover data at CR2. TABLE 21. Exponential regression analysis between the cumulative coral 55 species richness and the cumulative number of replicate transects at CR2. TABLE 22. Exponential regression analysis between the cumulative coral 57 species richness and the cumulative colony abundance at CR2. TABLE 23. Summary of the quadratic regression analysis results between the 67 % of total algal cover and several coral parameters. TABLE 24. Results of the 2-way crossed ANOSIM test for significant 71 differences of the structure of coral reef epibenthic communities at CR2. TABLE 25. Results of the pairwise ANOSIM significance test between 71 years at CR2. TABLE 26. Results of the pairwise ANOSIM significance test between 71 depth zones at CR2. TABLE 27a. Results of the SIMPER analysis of years 1997 vs 1998 at CR2. 72 TABLE 27b. Results of the SIMPER analysis of years 1997 vs 2001 at CR2. 72

6 TABLE 27c. Results of the SIMPER analysis of years 1997 vs 2002 at CR2. 72 TABLE 28a. Results of the SIMPER analysis of years 1998 vs 2001 at CR2. 73 TABLE 28b. Results of the SIMPER analysis of years 1998 vs 2002 at CR2. 73 TABLE 29. Results of the SIMPER analysis of years 2001 vs 2002 at CR2. 73 TABLE 30. Summary of the Caswell s neutral model V statistics for CR2. 75 TABLE 31. Summary of Pearson correlation matrix for different coral 75 species diversity indices at CR2 through time.

7 List of Figures FIGURE 1. Benthic habitat map of Culebra Island (modified after NOAA, ). FIGURE 2. Change in coral species richness at CR1. 18 FIGURE 3. Change in coral cumulative species richness at CR1. 19 FIGURE 4. Change in coral colony abundance at CR1. 20 FIGURE 5. Relationship among the cumulative coral colony abundance 21 and species richness at CR1. FIGURE 6. Dynamics of the mean colony abundance at CR1 ( ). 22 FIGURE 7. Change in the % of living coral cover at CR1. 23 FIGURE 8. Change in the % of total algal cover at CR1. 24 FIGURE 9. Change in the % of macroalgal cover at CR1. 26 FIGURE 10. Change in the % of filamentous algal cover at CR1. 27 FIGURE 11. Change in the % of cyanobacterial cover at CR1. 28 FIGURE 12. Change in the coral species diversity index at CR1. 30 FIGURE 13. Change in the coral species evenness at CR1. 31 FIGURE 14. Bray-Curtis dissimilarity classification of years (with depth 35 zones as replicates) based on the proportion of coral reef epibenthic categories at CR1. FIGURE 15. MDS-ordination plot of years (with depth zones as replicates) 36 based on the proportion of coral reef epibenthic categories at CR1. Stress level = FIGURE 16. K-dominance curve for coral species at CR1. 46 FIGURE 17. Change in coral species richness at CR2. 54 FIGURE 18. Change in coral cumulative species richness at CR2. 55 Pages

8 FIGURE 19. Change in coral colony abundance at CR2. 56 FIGURE 20. Relationship among the cumulative coral colony abundance 57 and species richness at CR2. FIGURE 21. Dynamics of the mean colony abundance at CR2 ( ). 58 FIGURE 22. Change in the % of living coral cover at CR2. 59 FIGURE 23. Change in the % of total algal cover at CR2. 60 FIGURE 24. Change in the % of macroalgal cover at CR2. 61 FIGURE 25. Change in the % of filamentous algal cover at CR2. 62 FIGURE 26. Change in the % of cyanobacterial cover at CR2. 63 FIGURE 27. Change in the coral species diversity index at CR2. 65 FIGURE 28. Change in the coral species evenness at CR2. 66 FIGURE 29. Bray-Curtis dissimilarity classification of years (with depth 69 zones as replicates) based on the proportion of coral reef epibenthic categories at CR2. FIGURE 30. MDS-ordination plot of years (with depth zones as replicates) 70 based on the proportion of coral reef epibenthic categories at CR2. Stress level = FIGURE 31. K-dominance curve for coral species at CR2. 78 FIGURE 32. White Plague Type II mortality in Montastrea annularis (Ellis 92 & Solander): A) Recent mortality (< 1 week); B) Old mortality (> 1 year). FIGURE 33. Top-down regulation model of a White-Plague Type II disease 102 outbreak. FIGURE 34. Top-down regulation model of herbivory by the Long-Spined 103 Sea Urchin, Diadema antillarum. FIGURE 35. Theoretical predicted interactions among herbivory and long- 104 term eutrophication effects in determining the dominant epibenthic components on shallow coral reefs.

9 FIGURE 36. Combined top-down and bottom up theoretical mechanisms 105 involved in the recent coral reef decline documented in the LPCMFR. FIGURE 37. Theoretical predictions of alternate stable states of the 111 LPCMFR coral reefs.

10 Appendix TABLE A1. Summary of the statistical power of the sampling effort at CR1. FIGURE A1. Draftman plot of coral species diversity indices at CR1 (1997). FIGURE A2. Draftman plot of coral species diversity indices at CR1 (1998). FIGURE A3. Draftman plot of coral species diversity indices at CR1 (1999). FIGURE A4. Draftman plot of coral species diversity indices at CR1 (2001). FIGURE A5. Draftman plot of coral species diversity indices at CR1 (2002). TABLE A2. Summary of the statistical power of the sampling effort at CR2. FIGURE A6. Draftman plot of coral species diversity indices at CR2 (1997). FIGURE A7. Draftman plot of coral species diversity indices at CR2 (1998). FIGURE A8. Draftman plot of coral species diversity indices at CR2 (2001). FIGURE A9. Draftman plot of coral species diversity indices at CR2 (2002). TABLE A3. TABLE A4. TABLE A5. TABLE A6. TABLE A7. Magnitude of changes in coral reef epibenthic parameters for the period of 1997 to 2002 at CR1 per each depth zone. Magnitude of changes in coral reef epibenthic parameters for the period of 1997 to 2002 at CR2 per each depth zone. Summary of some examples of rate of changes in the % of coral cover through the Caribbean during the last three decades (modified after Gardner, 2002). Coral:algal ratios at CR1. Coral:algal ratios at CR2.