Home Institution

Brown University

Publication Date

Fall 2014

Program Name

Madagascar: Biodiversity and Natural Resource Management


Coral reefs are microcosms of biodiversity and life. They are home to about a quarter of all marine life, yet amount to only about 1% of the world’s marine environment. Coral reefs are very vulnerable ecosystems; there are numerous threats to their health, such as damage by echinoderm and fish feeding, natural disasters, coral illness and bleaching events. Coral health fluctuates according to many of these factors and as a result of the fragile symbiotic balance between zooxanthellae algae and corals. Subsequently, coral health is an essential topic for analysis and assessment.

Coral reefs were assessed in Lokobe National Park, Nosy Be and Tanikely National Park, Nosy Tanikely in northwest Madagascar. At each site, there were 4 stations. The 4 stations in Lokobe are Antsaravy, Plaque Hely, Tsakabaniany, and Ampasindava. At Tanikely, surveys were conducted at North, South, East and West stations. In each station, there are 4 transects of 20 meters by 2 meters. I hypothesized that Lokobe’s corals would be less healthy and less diverse, because of their close proximity to homes and human impacts. Also, Tanikely will be healthier and more diverse because it is well protected and only visited by tourists during the day, with no permanent inhabitants.

In this study, coral health is examined through a variety of visual analyses and calculations. The tests conducted are species richness, species evenness, coral forms, coral cover percentage, reef health classification, relative species abundance, juvenile species recruitment, and echinoderms encountered and coral bleaching/illness. All of these totals attribute to the overall health of each coral reef site.. Coral reefs are classified on the ASEAN scale of reef health from bad to excellent. This scale classifies coral reefs by presence of hard coral. Overall, corals are healthier in Lokobe National Park. There is a large amount of hard coral cover, juvenile species recruitment and relatively small amounts of coral bleaching and illness. However, there is less coral species diversity and more species evenness. In Lokobe, less echinoderms were encountered compared to the plethora found at Tanikely. At Tanikely National Park, corals are in generally worse health. There is less hard coral cover, more coral bleaching and illness, and more reef degradation. Moreover, there is higher species richness at Tanikely than that of Lokobe, and there is less species evenness. However, there are many echinoderms, especially sea urchins, which are an indicator of reef degradation. Coral reefs are a vital marine ecosystem that are homes to many organisms that people depend on. Reef health is important to analyze and assess in order to adequately protect these habitats.


Environmental Indicators and Impact Assessment | Natural Resources and Conservation | Natural Resources Management and Policy | Oceanography and Atmospheric Sciences and Meteorology


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