Herbivory on coral reefs: community structure following mass mortalities of sea urchins

1987 ◽  
Vol 113 (1) ◽  
pp. 39-59 ◽  
Author(s):  
Terence P. Hughes ◽  
Daniel C. Reed ◽  
Mary-Jo Boyle
2014 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
S. GARCIA-SANZ ◽  
P. G. NAVARRO ◽  
F. TUYA

Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula) at Gran Canaria Island (eastern Atlantic) via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds) within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula) with the most conspicuous species (D. africanum) in the study area.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Leor Korzen ◽  
Alvaro Israel ◽  
Avigdor Abelson

Herbivory is an important structuring factor in coral reefs, influencing seaweed abundance, competitive interactions between seaweeds and corals, and coral reef resilience. Despite reports of a drastic increase in the cover of benthic algae and turf dominancy in the coral reefs of Eilat, Red Sea, very little is known about the factors responsible for this phenomenon or the possible effects of herbivory on turf algae and coral recruits. Here, we examine the effects of herbivory by experimentally exposing turf algae and coral recruits to grazing activities of herbivorous fish and sea urchins. Using remote video cameras to document removal of algae and coral spats, we show that the main grazing impact is due to daily grazing by fishes, whereas the significant impact of sea urchins is mainly expressed in their adverse effect on the survival of coral recruits, with a relatively low effect on algal biomass. These findings contribute to our understanding of the factors influencing turf algae establishment and proliferation, and the survival of coral recruits on the coral reefs of Eilat. The clear differences between the impact of herbivorous fish and that of sea urchins, on the Eilat reefs, have critical implications for reef resilience and restoration measures.


Coral Reefs ◽  
2006 ◽  
Vol 26 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Jocelyn Brown-Saracino ◽  
Paulette Peckol ◽  
H. Allen Curran ◽  
Martha L. Robbart

2001 ◽  
Vol 71 (1) ◽  
pp. 49 ◽  
Author(s):  
John M. Pandolfi ◽  
Jeremy B. C. Jackson

2002 ◽  
Vol 29 (4) ◽  
pp. 460-483 ◽  
Author(s):  
Timothy R. McClanahan

In this paper the current status of coral reefs, predictions concerning the ecological state of coral reefs to the 2025 time horizon and the research needs that can help understanding and management activities that might alleviate detrimental ecological changes are evaluated and discussed. The present rate of CO2 emissions will produce an atmospheric concentration in 100 years not experienced during the past 20 million years and water temperatures above those of the past interglacial 130 000 years before present. Human influences on water temperatures, seawater chemistry (toxic substances, nutrients and aragonite saturation), the spread of diseases, removal of species and food web alterations are presently changing reef ecology. A significant ecological reorganization is underway and changes include a reduction in calcifying and zooxanthellae-hosting organisms, their obligate symbionts, and species at higher trophic levels, with an increase in generalist species of low trophic level that are adapted to variable environments. Late-successional fleshy brown algae of low net productivity or non-commercial invertebrates such as sea urchins, starfish and coral-eating snails will dominate many reefs. These changes will be associated with a loss of both net benthic and fisheries production and inorganic carbonate deposition; this will reduce reef complexity, species richness, reef growth and increase shoreline erosion. To avert these changes management is needed at both global and local levels. Both levels need to reduce greenhouse gases and other waste emissions and renew efforts to improve resource management including restrictions on the use of resources and globalization of resource trade, run-off and waste production, and balancing potential reef production and resource consumption.


Author(s):  
FARID KAMAL MUZAKI ◽  
EDWIN SETIAWAN ◽  
GHULAM FATHIR AUTHAR INSANY ◽  
NURUL KUSUMA DEWI ◽  
IWENDA BELLA SUBAGIO

Abstract. Muzaki FK, Setiawan E, Insany GFA, Dewi NK, Subagio IB. 2019. Community structure of Echinoderms in seagrass beds of Pacitan beaches, East Java, Indonesia. Biodiversitas 20: 1787-1793. In this study, we attempt to access diversity and community structure of Echinoderms on seagrass beds in each three belt transect (width 2 m, length 100 m) in Tawang and Pidakan beaches, Pacitan, East Java, Java. Observed parameters were species richness, composition, and abundance, as well as diversity indices: Shannon-Wiener's diversity index (H'), Simpson's dominance index (D) and Pielou's evenness index (J). At the end of the study, we identified one species of sea star (Asteroidea), seven species of brittle stars (Ophiuroidea), ten species of sea cucumbers (Holothuroidea) andnine species of sea urchins (Echinoidea). The most dominant species were Ophiocoma dentata (F. Ophiocomidae), Diadema setosum (F. Diadematiidae), Ophiomastix annulosa (F. Ophiocomidae) and Echinometra mathaei (F. Echinometridae). Value of H’ ranged from 0.538 to 1.252 in Tawang and 1.041 to 1.704 in Pidakan; which showing higher species richness and diversity in Pidakan. Echinoderm in the study area was not evenly distributed; D. setosum was very dominant in Tawang beach, while those three other species were more common in Pidakan. Furthermore, most of Holothuroid and Ophiuroid were found only in Pidakan which have relatively more complex habitat.


2016 ◽  
Author(s):  
Justin H. Baumann ◽  
Joseph E. Townsend ◽  
Travis A. Courtney ◽  
Hannah E. Aichelman ◽  
Sarah W. Davies ◽  
...  

AbstractCoral reefs are increasingly threatened by global and local anthropogenic stressors such as rising seawater temperature, nutrient enrichment, sedimentation, and overfishing. Although many studies have investigated the impacts of local and global stressors on coral reefs, we still do not fully understand how these stressors influence coral community structure, particularly across environmental gradients on a reef system. Here, we investigate coral community composition across three different temperature and productivity regimes along a nearshore-offshore gradient on lagoonal reefs of the Belize Mesoamerican Barrier Reef System (MBRS). A novel metric was developed using ultra-high-resolution satellite-derived estimates of sea surface temperatures (SST) to classify reefs as exposed to low (lowTP), moderate (modTP), or high (highTP) temperature parameters over 10 years (2003 to 2012). Coral species richness, abundance, diversity, density, and percent cover were lower at highTP sites relative to lowTP and modTP sites, but these coral community traits did not differ significantly between lowTP and modTP sites. Analysis of coral life history strategies revealed that highTP sites were dominated by hardy stress tolerant and fast-growing weedy coral species, while lowTP and modTP sites consisted of competitive, generalist, weedy, and stress-tolerant coral species. Satellite-derived estimates of Chlorophyll-a (chl-a) were obtained for 13-years (2003-2015) as a proxy for primary production. Chl-a concentrations were highest at highTP sites, medial at modTP sites, and lowest at lowTP sites. Notably, thermal parameters correlated better with coral community traits between site types than productivity, suggesting that temperature (specifically number of days above the thermal bleaching threshold) played a greater role in defining coral community structure than productivity on the MBRS. Dominance of weedy and stress-tolerant genera at highTP sites suggests that corals utilizing these two life history strategies may be better suited to cope with warmer oceans and thus may warrant protective status under climate change.


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