Kristina Timmerman, Biology
Algal diversity is important in the Galápagos Islands’ littoral ecosystems because it is part of the photosynthetic role in the food web. Male damselfish (Stegastes sps.) may play a key role in the maintenance of algal diversity due to their territorial behavior; they actively clean territories and thereby, open up niches for algal growth. We investigated the damselfish role in algal coverage and diversity and predicted that there will be greater mean coverage and number of species within territories. Results from this study will contribute to the knowledge base concerning natural diversity maintenance. Data collection occurred during low tide between 20 and 26 July, 2015 at two beaches on Isla San Cristόbal. Using 50cm x 50cm PVC quadrants, we compared algal coverage and species diversity on damselfish territories and on randomly selected areas (“non-territories”) within 7 meters of the focal territory (N = 50 for each category at each beach). Using a chi-square goodness of fit analysis protocol, we found a significant difference between the mean number of algal species within a territory as compared to non-territories at both beaches (Playa Mann: 2.5 vs. 2.0, respectively and La Loberίa: 3.0 and 2.5, respectively). At La Loberίa, there was significantly less algal coverage in non-territories (P < 0.001). There was no difference in mean algal coverage at Playa Mann (P = 0.94). Reduced algal coverage within non-territories at La Loberίa may be a function of a generally shallower area and high snorkeling activities. Lower algal coverage may be explained by daily abrasion of the bottom by the public. In terms of mean algal diversity, results are in agreement with our prediction and damselfish appear to play an important role in the maintenance of higher algal diversity. This research provides valuable insight into the biodiversity of algal species in marine ecosystems, as well as further supports the importance of Damselfish in regards to upkeep of these marine ecosystems.
DeVaan, Ian; Koch, Brian; Goodman, Paige; and Madden, Claire, "Damselfish and their Effect on the Biodiversity of Algal Species: A Continuation of Research in the Galápagos Islands" (2016). Celebrating Scholarship & Creativity Day. 80.