Browsing by Subject "coral reefs"
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Item Open Access A ridge-to-reef framework to protect Guam's water quality and coral reef ecosystem(2023-04-25) Castro, FrancesWatershed pollution and fisheries exploitation are the priority, chronic stressors that impact Guam’s coral reefs. Yet, quantifying the relative contribution of individual stressors to any particular reef is difficult due to natural variations in biological assemblages across island scales and uncertain site-specific disturbance histories. A study of 26 sites in southern Guam watersheds shows the effects of pollution on coral reef and fish assemblages. Community, government, and legislative action need to take place to improve Guam’s water quality standards.Item Open Access Coral-associated Crabs and Macroalgae Alter Disease Spread in Branching Corals on the Great Barrier Reef(2020) Renzi, Julianna JollyDisease is an important driver of coral loss regionally and is projected to become more severe as temperatures increase around the world. Although there has been substantial research into the abiotic factors (e.g. temperature, nutrients) controlling coral diseases, we know significantly less about the biotic factors (i.e. species interactions) influencing disease dynamics. We examined how the species living on and within corals affect coral tissue loss from a white syndrome-like condition on Heron Island in the southern section of the Great Barrier Reef. We exposed Acropora aspera fragments in flow-through tanks to a fully crossed factorial experiment with three factors: the presence of a common symbiotic crab (Cyclodius ungulatus), contact with a common macroalgal complex, and simulated wounding mimicking fish predation. We found that crab presence increased coral survival from a white syndrome-type disease by over 25%, likely by removing macroalgae if present and by cleaning infected tissue. Conversely, contact with macroalgae dramatically increased coral mortality, with the chance of survival dropping to nearly 0 by the end of 25 days for corals that were in contact with algae. Wounding had no direct effect on coral health, but wounded corals with crabs did significantly better than corals with no wounding and crabs, which may be the result of coral-crab signaling. We suggest that A. aspera may produce nutrient-rich mucus when wounded, which attracts crab symbionts that help slow disease progression. These results suggest that incorporating biotic interactions into restoration designs may dramatically improve restoration outcomes and that adding beneficial symbionts may improve disease resilience at a local level.
Item Open Access Development of a Coral Reef Restoration Framework: A Maldivian Case Study(2012-04-27) Kovacs, KaitlinThe observed coral reef decline has prompted alternative protection measures beyond traditional conservation efforts. Restoration can be used to reverse reef degradation and has been practiced around the world, particularly in developing countries where livelihoods rely on the ecosystems, such as the Maldives. As an atoll nation with more oceanic territory than terrestrial territory, the country’s vulnerability to increased development and unprecedented environmental changes requires effective coral reef management. A literature review was conducted to develop a restoration framework, based on common coral reef restoration practices, which can be used by Maldivian reef managers and others to prioritize restoration methods and to involve team members from several sectors. Specifically, the framework can be used by the Maldives to support inclusion of passive restoration options, sector integration, and local engagement to promote the country’s efforts in coral reef protection.Item Open Access Do Migrants Degrade Coastal Environments? Migration, Natural Resource Extraction and Poverty in North Sulawesi, Indonesia.(Hum Ecol Interdiscip J, 2005-06) Cassels, Susan; Curran, Sara R; Kramer, RandallRecent literature on migration and the environment has identified key mediating variables such as how migrants extract resources from the environment for their livelihoods, the rate and efficiency of extraction, and the social and economic context within which their extraction occurs. This paper investigates these variables in a new ecological setting using data from coastal fishing villages in North Sulawesi, Indonesia. We do not find as many differences between migrant and non-migrant families regarding destructive fishing behavior, technology, and investment as might have been expected from earlier theories. Instead, the context and timing of migrant assimilation seems to be more important in explaining apparent associations of migration and environmental impacts than simply migrants themselves. This finding fits well with recent literature in the field of international migration and immigrant incorporation.Item Open Access DOES PROTECTION CULTIVATE MORE RESILIENT REEFS? : ASSESSNG THE LONG-TERM EFFECTS OF BELIZE’S NO-TAKE MANAGEMENT ZONES ON THE POST-DISTURBANCE RECOVERY OF CORALS(2010-04-30T18:35:43Z) Fieseler, ClareCoral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. Under the current trends, disturbance events are likely to increase in rate and severity. It is critically important to create management strategies that enhance the ability of coral reefs to absorb shocks, resist phase-shifts, and regenerate after such perturbations. This project assesses the capacity of no-take management zones to foster coral resilience in Belize in the 10 years after a major disturbance. In 1998, the Belize Barrier Reef Complex (BBRC) experienced bleaching and hurricane events that effectively halved coral cover. Using video-based reef quantification, this project builds on a robust dataset describing benthic composition immediately before and at three sampling intervals after these major disturbances. The results of this Master’s Project reveal that protection offered by no-take zones (NTZ) has no detectable effect on changes to benthic composition. Coral assemblages show no long-term recovery on either NTZ or fished reefs. As a result, macroalgae cover increased significantly, perhaps past certain resiliency thresholds. Insufficient protection may be attributed to design factors related to size, proximity to other stressors, and isolation. The results make clear that Belize’s reefs are changing at an increasing rate away from desirable ecological baselines. Conservation and government leaders in Belize are thus urged to look beyond purely spatial options in crafting tools for reef resilience.Item Open Access Hydrodynamics influence coral performance through simultaneous direct and indirect effects(ECOLOGY, 2015-06) Lenihan, HS; Hench, JL; Holbrook, SJ; Schmitt, RJ; Potoski, MItem Open Access Influence of Substrate on Coral Reef Fish Communities(2008-06-23) Neely, Karen LynnCoral reef fish coexist in a state of high diversity that has not been successfully explained by niche diversification, larval supply, differential mortality, or a suite of other proposed factors. These processes are all occurring on a diverse substrate that would be expected to affect the abundance and distribution of fish by directing habitat preferences as well as affecting competitive and predatory success. I conducted correlational studies on healthy and degraded Caribbean reefs that addressed fish abundances at the levels of community, species, and age class. I also experimentally tested habitat preferences in two ways: choice experiments on adults of common species that determined preferences for live coral and rugosity in an isolated environment, and monitoring of artificial reefs differing in live coral cover that tested habitat selection of adults and juveniles in the field. These observations all show that live coral had no effect on community parameters such as abundance or diversity, but that rugosity was positively related to species richness. However, these measures of the community masked differences at the species and age class level. A handful of species exhibited positive or negative preferences for live coral, but these selections did not follow a taxonomic or trophic-level classification. Species within the genus Stegastes, for example, could either aggregate towards or avoid live coral. One species even reversed its habitat preference as it matured. Field distributions were not determined solely by these habitat preferences, but inclusion of competitive interactions into a multi-factorial model explained distribution of some species. Results suggest that changes in live coral cover, an increasingly common phenomenon, would not affect fish at a community level, but could affect a few species through changes to recruitment or alteration of competitive interactions.