Abstract

Calcification and reef growth processes dominated by corals and calcifying algae are threatened by climate and fishing disturbances. Twenty-seven environmental, habitat, and species interaction variables were tested for their influence on coral and calcifier cover in 201 western Indian Ocean coral reefs distributed across ~20° of latitude and longitude and up to 20 m deep. These variables predicted more of the total between-site variance of calcifying organism cover (~50%) than coral cover (~20%). Satellite-derived environmental variables of temperature, light, and water quality predicted more of the coral and calcifier cover than feeding interactions when groups of related variables were analyzed separately. Nevertheless, when simultaneously evaluating all variables, the environmental variables better predicted coral cover, but proxies of feeding interactions better predicted calcifier cover. Coral and calcifier cover were most consistently negatively influenced by sea surface temperature distributions (right skewness), but the orangelined triggerfish Balistapus undulatus consistently had a strong positive association with coral and
calcifier cover. Herbivorous fish and Diadematidae sea urchins were not positively associated with coral and calcifier cover. A primary prey of B. undulatus, the rock-boring sea urchin Echinometra mathaei, had a strong negative association with coral cover and particularly calcifier cover. Island reefs had higher calcifier abundance than fringing reefs, which probably results from high Acropora and B. undulatus but low E. mathaei abundance. When comparing all variables and models, these taxonomic associations had more influence than environmental stress variables on calcifiers. Given the important predatory role of B. undulatus in controlling E. mathaei populations, fishing restrictions on this species could help attenuate calcification losses predicted by climate change.



Related content

New Publication: Kenyan and Mozambican coral reef ‘carbonate budgets’ contribute to international picture of corals under sea-level rise.

SPACES coral reef surveys have contributed to an international picture of how reefs might be able to grow to keep up with sea-level rise, recently published in Nature. The growth of coral reefs is strongly influenced by the amount and types of coral living on the reef surface, but across both regions this growth is […]

Read more
Artisanal fisheries in Cabo Delgado, Mozambique: rural vs urban fishing centers

This working paper investigates the relationship between gear, catch and income generated by the fishers in different seasons. SPACES researchers collected data using fish catch surveys at landing sites in Pemba town, Vamizi and Lalane. A standard questionnaire was used to collect the effort and location of the fishery. The fishery shows a wide range […]

Read more
Changing dynamics of reef framework production in the Western Indian Ocean – Fraser Januchowski-Hartley et al.(1.2 MB)

Fraser Januchowski-Hartley’s presentation at the 2015 WIOMSA symposium on carbonate budget and current coral condition at SPACES sites, Mombasa, Shimoni, Vamizi, and Pemba.

Read more
Linking reef ecology to island building: Parrotfish identified as major producers of island-building sediment in the Maldives. Geology 2015

Reef islands are unique landforms composed entirely of sediment produced on the surrounding coral reefs. Despite the fundamental importance of these ecological-sedimentary links for island development and future maintenance, reef island sediment production regimes remain poorly quantified. Using census and sedimentary data from Vakkaru island (Maldives), a sand-dominated atoll interior island, we quantify the major […]

Read more
Remote coral reefs can sustain high growth potential and may match future sea-level trands. Nature Scientific Reports 2015

Climate-induced disturbances are contributing to rapid, global-scale changes in coral reef ecology. As a consequence, reef carbonate budgets are declining, threatening reef growth potential and thus capacity to track rising sea-levels. Whether disturbed reefs can recover their growth potential and how rapidly, are thus critical research questions. Here we address these questions by measuring the […]

Read more
Environmental variability indicates a climate-adaptive center under threat in northern Mozambique coral reefs. Ecosphere 2017

A priority for modern conservation is finding and managing regions with environmental and biodiversity portfolio characteristics that will promote adaptation and the persistence of species during times of rapid climate change. The latitudinal edges of high-diversity biomes are likely to provide a mixture of environmental gradients and biological diversity that meet the portfolio criteria needed […]

Read more
Drivers and predictions of coral reef budget trajectories. Proceedings Of The Royal Society B-biological Sciences 2017

Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth […]

Read more
Ecological Underwater Surveys

All information including publications, conference presentations and news items related to underwater ecological surveys is tagged below.

Read more
New paper from SPACES team members shows the positive correlation between the orange-lined triggerfish and calcifier cover

SPACES Co-investigators, Tim McClanahan and Nyawira Muthiga, have recently published the paper, Similar impacts of fishing and environmental stress on calcifying organisms in Indian Ocean coral reefs (Open Access– free to read) in the Marine Ecology Progress Series. They investigated coral and calcifier cover in 201 western Indian Ocean reefs.  McClanahan and Muthiga found that coral and calcifier cover […]

Read more
Aligning Global Indicators for Coral Reef Fisheries Monitoring in the Western Indian Ocean Workshop

Recently, a member of the SPACES team attended a regional workshop in Nosy Be, Madagascar from 27 to 28 April, 2015. The workshop was convened by the Wildlife Conservation Society (WCS) and Dr Emily Darling with the aim to bring together various researchers working on coral reef fisheries in the Western Indian Ocean (WIO). The workshop […]

Read more
How important are parrotfish for coral reef islands?

Parrotfishes are a beautiful, colourful and ubiquitous group of fishes that are present on coral reefs around the world. They’ve received a lot of attention due to their importance in both fisheries, and in how they can help to maintain coral reef health through preventing outbreaks of fleshy macroalgae, that can overgrow and out-compete corals. […]

Read more