scholarly journals A threat to coral reefs multiplied? Four species of crown-of-thorns starfish

2008 ◽  
Vol 4 (6) ◽  
pp. 696-699 ◽  
Author(s):  
Catherine Vogler ◽  
John Benzie ◽  
Harilaos Lessios ◽  
Paul Barber ◽  
Gert Wörheide

In the face of ever-increasing threats to coral reef ecosystems, it is essential to understand the impact of natural predators in order to devise appropriate management strategies. Destructive population explosions of the crown-of-thorns starfish Acanthaster planci have devastated coral reefs throughout the Indo-Pacific for decades. But despite extensive research, the causes of outbreaks are still unclear. An important consideration in this research is that A. planci has been regarded as a single taxonomic entity. Using molecular data from its entire distribution, we find that A. planci is in fact a species complex. This discovery has important consequences for future coral reef research, and might prove critical for successful reef conservation management.

2021 ◽  
Vol 10 (2) ◽  
pp. 151-161
Author(s):  
Insafitri Insafitri ◽  
Eka Nurahemma Ning Asih ◽  
Wahyu Andy Nugraha

Wisata snorkeling terumbu karang di perairan pulau Gili Labak merupakan salah satu sektor wisata bahari yang sedang dikembangkan oleh pemerintah kebupaten Sumenep Madura sejak tahun 2014 hingga saat ini. Peningkatan jumlah wisatawan yang terjadi pada beberapa tahun terakhir dapat menimbulkan resiko tekanan dan kerusakan ekosistem terumbu karang di area snorkeling secara berkala. Penelitian ini bertujuan untuk mengetahui dampak kegiatan wisatawan sebelum, selama dan sesudah snorkeling terhadap ekosistem terumbu karang yang dikaji dengan mengetahui jenis karang yang mendominasi, status persentase tutupan terumbu karang serta potensi Dampak Wisata Bahari (DWB) snorkeling di lokasi wisata snorkeling pulau Gili Labak Sumenep. Persentase penutupan lifeform karang pulau Gili Labak khususnya di area snorkelling didominasi oleh karang hidup sebanyak 74% dan unsur abiotik sebesar 22%. Jenis karang yang mendominasi pulau Gili Labak adalah Acropora Branching sebesar 19,88% dan Coral Foliose sebesar 10,25%. Selama waktu 6 minggu pengamatan terjadi penurunan total karang sebesar 0,64% yang termasuk kategori rusak ringan, dimana sebagian besar kerusakan terjadi pada karang dengan bentuk pertumbahan branching misalnya Acropora Submassive dan Coral Submassive. Penurunan persen tutupan karang yang tinggi terjadi setelah kegiatan snorkeling (after) yang dilakukan oleh wisatawan. Analisa potensi Dampak Wisata Bahari (DWB) snorkeling pada terumbu karang di perairan Gili Labak selama 6 minggu pengamatan masuk dalam kategori rendah yaitu berkisar 0,052% hingga 0,085%. Faktor penyebab kecilnya nilai presentase Dampak Wisata Bahari (DWB) ini diduga karena waktu pengamatan cenderung pendek dan jenis karang yang mendominasi yaitu Acropora. Acropora memiliki kemampuan regenerasi lebih cepat dibandingkan jenis lainnya.  The snorkeling activity around coral reefs in the waters of Gili Labak is one of the marine tourism sectors that is being developed by the Sumenep Madura district government since 2014. Increasing number of tourists that occurs in recent years pose a risk of pressure and damage to coral reef ecosystems in the snorkeling area. This study aims to determine the impact of tourist activities before, during and after snorkeling on coral reef ecosystems that are studied by knowing the type of dominated coral, the percentage status of coral cover and the potential Impact of snorkeling at the snorkeling sites of the island of Gili Labak Sumenep. The percentage of coral cover in the island of Gili Labak especially in the snorkelling area is dominated by live coral ( 74%) and abiotic elements by 22%. Coral species that dominate the island of Gili Labak are Acropora Branching at 19.88% and Coral Foliose at 10.25%. During the 6-week observation there was a decrease in live coral cover by 0.64% which was categorized as minor damage, most of the damage occurred to branching   Acropora, sub-massive Acropora and Coral Sub-massive. The high percent decrease in coral cover occurred after snorkeling conducted by tourists. Analysis of the potential impact of snorkeling on coral reefs in the waters of Gili Labak for 6 weeks of observation is in the low category, ranging from 0.052% to 0.085%. The factor causing the small impact of Marine Tourism is presumably because the observation time tends to be short and the dominant coral species is Acropora. Acropora has the ability to regenerate faster than other types.


Diversity ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 107 ◽  
Author(s):  
Harsuko Riniwati ◽  
Nuddin Harahab ◽  
Zainal Abidin

Coral reef ecosystems provide many ecological, economic, and social benefits. Despite their numerous functions, coral reefs are in a vulnerable state due to the effects of human activities. The condition of coral reefs has decreased in many parts of the world. Therefore, coral reef examinations need to be carried out continuously in order to formulate management strategies that can reduce their vulnerability over time. This study aims to analyze the vulnerability index of coral reefs, the sensitivity of coral reefs to the causes of vulnerability, and the adaptive capacity to anticipate vulnerability. The primary data are the perceptions of respondents’ who filled out a prepared questionnaire which included eight dimensions: information on the environmental conditions, fishing ports, fishing areas, coastline settlements, tourism management, tourism attractions, socio-economic conditions and population, and aquaculture. The data were analyzed using multidimensional scaling (MDS). The results of the analysis revealed that fishing ports, fishing areas, and environmental condition are high vulnerability indexes which cause damage to coral reefs. The highest coral reef vulnerability sensitivity was found to be triggered by the distance from fishing areas and the distance from fishing vessel channels. An inverse relationship between vulnerability and adaptive capacity was shown. Hence distance from fishing areas and distance from fishing vessel channels are the attributes that have low adaptive capacity.


2019 ◽  
Vol 19 (3) ◽  
pp. 385-394
Author(s):  
Nguyen Thuy Linh ◽  
Nguyen Tai Tue ◽  
Mai Trong Nhuan

Coral reefs play a crucial role in providing ecosystem services for the coastal communities. However, the resilience of coral reefs is quickly degraded due to both global and local stressors, including climate change and marine pollution. Hon La island in Quang Binh province, Vietnam is one of the most important coral reef ecosystems. However, this area was heavily influenced by human activities and marine pollution. Therefore, the present study is implemented in order to evaluate the resilience of coral reefs in Hon La island for proposing sustainable development solutions. The proposed indicator framework consisted of three dimensions (coral diversity, biodiversity and environment), containing 26 indicators that potentially provided the quantified methods for decision makers to inform a range of management strategies in protecting coral reefs and using natural resources effectively. Results showed that coral reefs in Hon La island had a low resilient index, about 0.369 because of a degradation of diversity, seawater contaminated by oils and the high turbidity. Several solutions were proposed to enhance the resilience of coral reefs, including the establishment of marine protected areas; integrated management of the coastal zone; rehabilitation of coral reefs and application of co-management models. The theoretical framework from the present study could be potentially applied to evaluate the coral reef resilience in other marine areas in Vietnam with appropriate modification.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Alexandra M. Good ◽  
Keisha D. Bahr

AbstractCoral reefs are one of the most productive and biodiverse ecosystems in the world. Humans rely on these coral reef ecosystems to provide significant ecological and economic resources; however, coral reefs are threatened by numerous local and global anthropogenic factors that cause significant environmental change. The interactions of these local and global human impacts may increase the rate of coral reef degradation. For example, there are many local influences (i.e., sedimentation and submarine groundwater discharge) that may exacerbate coral bleaching and mortality. Therefore, researchers and resource managers cannot limit their narratives and actions to mitigating a sole stressor. With the continued increase in greenhouse gas emissions, management strategies and restoration techniques need to account for the scale at which environmental change occurs. This review aims to outline the various local and global anthropogenic stressors threatening reef resiliency and address the recent disagreements surrounding present-day conservation practices. Unfortunately, there is no one solution to preserve and restore all coral reefs. Each coral reef region is challenged by numerous interactive stressors that affect its ecosystem response, recovery, and services in various ways. This review discusses, while global reef degradation occurs, local solutions should be implemented to efficiently protect the coral reef ecosystem services that are valuable to marine and terrestrial environments.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Anggita Kartikasari ◽  
TODHI PRISTIANTO ◽  
RIZKI HANINTYO ◽  
EGHBERT ELVAN AMPOU ◽  
TEJA ARIEF WIBAWA ◽  
...  

Abstract. Kartikasari A, Pristianto T, Hanintyo R, Ampou EE, Wibawa TA, Borneo BB. 2021. Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia. Biodiversitas 22: 4766-4774. Satellite optical imagery datasets integrated with in situ measurements are widely used to derive the spatial distribution of various benthic habitats in coral reef ecosystems. In this study, an approach to estimate spatial coverage of those habitats based on observation derived from Sentinel-2 optical imagery and a field survey, is presented. This study focused on the Lovina coral reef ecosystem of Northern Bali, Indonesia to support deployment of artificial reefs within the Indonesian Coral Reef Garden (ICRG) programme. Three specific locations were explored: Temukus, Tukad Mungga, and Baktiseraga waters. Spatial benthic habitat coverages of these three waters was estimated based on supervised classification techniques using 10m bands of Sentinel-2 imagery and the medium scale approach (MSA) transect method of in situ measurement.The study indicates that total coverage of benthic habitat is 61.34 ha, 25.17 ha, and 27.88 ha for Temukus, Tukad Mungga, and Baktiseraga waters, respectively. The dominant benthic habitat of those three waters consists of sand, seagrass, coral, rubble, reef slope and intertidal zone. The coral reef coverage is 29.48 ha (48%) for Temukus covered by genus Acropora, Isopora, Porites, Montipora, Pocillopora. The coverage for Tukad Mungga is 8.69 ha (35%) covered by genus Acropora, Montipora, Favia, Psammocora, Porites, and the coverage for Baktiseraga is 11.37 ha (41%) covered by genus Montipora sp, Goniastrea, Pavona, Platygyra, Pocillopora, Porites, Acropora, Leptoseris, Acropora, Pocillopora, Fungia. The results are expected to be suitable as supporting data in restoring coral reef ecosystems in the northern part of Bali, especially in Buleleng District.


2017 ◽  
Vol 14 (6) ◽  
pp. 1739-1772 ◽  
Author(s):  
Kimberly K. Yates ◽  
David G. Zawada ◽  
Nathan A. Smiley ◽  
Ginger Tiling-Range

Abstract. Coral reefs serve as natural barriers that protect adjacent shorelines from coastal hazards such as storms, waves, and erosion. Projections indicate global degradation of coral reefs due to anthropogenic impacts and climate change will cause a transition to net erosion by mid-century. Here, we provide a comprehensive assessment of the combined effect of all of the processes affecting seafloor accretion and erosion by measuring changes in seafloor elevation and volume for five coral reef ecosystems in the Atlantic, Pacific, and Caribbean over the last several decades. Regional-scale mean elevation and volume losses were observed at all five study sites and in 77 % of the 60 individual habitats that we examined across all study sites. Mean seafloor elevation losses for whole coral reef ecosystems in our study ranged from −0.09 to −0.8 m, corresponding to net volume losses ranging from 3.4  ×  106 to 80.5  ×  106 m3 for all study sites. Erosion of both coral-dominated substrate and non-coral substrate suggests that the current rate of carbonate production is no longer sufficient to support net accretion of coral reefs or adjacent habitats. We show that regional-scale loss of seafloor elevation and volume has accelerated the rate of relative sea level rise in these regions. Current water depths have increased to levels not predicted until near the year 2100, placing these ecosystems and nearby communities at elevated and accelerating risk to coastal hazards. Our results set a new baseline for projecting future impacts to coastal communities resulting from degradation of coral reef systems and associated losses of natural and socioeconomic resources.


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.


1995 ◽  
Vol 2 (2) ◽  
pp. 142 ◽  
Author(s):  
Ann L. Poulsen

Large, colourful coral reef gastropods including the Giant Triton Charonia tritonis,helmet shells (Cassidae), cowries (Cypraeidae) and volutes (Volutidae) are exploited in an unregulated and unsustainable way throughout much of the Indo-Pacific region. The consequences for their populations, for the populations of their prey or for the ecology of their habitats are rarely considered. Serious decline in stocks of edible coral reef molluscs through unregulated harvesting demonstrates the need for controls on the collection and trade of commercially important species. Continued, unrestricted collecting will eventually lead to the local extinction of vulnerable species on substantial numbers of reefs. Research on the biology and ecology of ornamental species is urgently needed to facilitate the implementation of appropriate management strategies for long-term utilization. A co-operative effort to monitor and regulate trade will also contribute toward the maintenance of sustainable gastropod populations on coral reefs.


1998 ◽  
Vol 22 (2) ◽  
pp. 190-221 ◽  
Author(s):  
Heather Holden ◽  
Ellsworth LeDrew

According to the 1993 colloquium on the ‘Global status of coral reefs', our understanding of the global role of coral reefs is inadequate. To increase our understanding, an accurate large-scale mapping and monitoring programme is necessary. Historically, coastal zones have been mapped using traditional surveying tools such as topographic maps, nautical charts, existing aerial photographs and direct observations. Although less expensive than digital imagery, exclusive use of these traditional tools may not be practical for monitoring large or remote coral reef ecosystems accurately. Researchers are attempting to develop an adequate coral reef mapping system based on digital remote sensing, but are impeded by issues such as effects of the intervening water column and spectral distinction of bottom types. The two variables discussed, which will contribute to our understanding of the global role of coral reefs, are: 1) remote sensing of submerged coral reefs in general; and 2) remote sensing of coral bleaching in particular. A summary of radiative transfer theory is presented and case studies of attempts at mapping remotely the geographic extent and health of submerged ecosystems, as well as a discussion of the remote estimation of water depth and quality. Problems in the translation and delivery of information to the end user are presented, and possible solutions suggested.


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