Ongoing declines in the structure and function of the world’s coral reefs require novel approaches to sustain these ecosystems and the millions of people who depend on them3. A presently unexplored ...approach that draws on theory and practice in human health and rural development is to systematically identify and learn from the ‘outliers’—places where ecosystems are substantially better (‘bright spots’) or worse (‘dark spots’) than expected, given the environmental conditions and socioeconomic drivers they are exposed to. Here we compile data from more than 2,500 reefs worldwide and develop a Bayesian hierarchical model to generate expectations of how standing stocks of reef fish biomass are related to 18 socioeconomic drivers and environmental conditions. We identify 15 bright spots and 35 dark spots among our global survey of coral reefs, defined as sites that have biomass levels more than two standard deviations from expectations. Importantly, bright spots are not simply comprised of remote areas with low fishing pressure; they include localities where human populations and use of ecosystem resources is high, potentially providing insights into how communities have successfully confronted strong drivers of change. Conversely, dark spots are not necessarily the sites with the lowest absolute biomass and even include some remote, uninhabited locations often considered near pristine6. We surveyed local experts about social, institutional, and environmental conditions at these sites to reveal that bright spots are characterized by strong sociocultural institutions such as customary taboos and marine tenure, high levels of local engagement in management, high dependence on marine resources, and beneficial environmental conditions such as deep-water refuges. Alternatively, dark spots are characterized by intensive capture and storage technology and a recent history of environmental shocks. Our results suggest that investments in strengthening fisheries governance, particularly aspects such as participation and property rights, could facilitate innovative conservation actions that help communities defy expectations of global reef degradation.
The worldwide decline of coral reefs necessitates targeting management solutions that can sustain reefs and the livelihoods of the people who depend on them. However, little is known about the ...context in which different reef management tools can help to achieve multiple social and ecological goals. Because of nonlinearities in the likelihood of achieving combined fisheries, ecological function, and biodiversity goals along a gradient of human pressure, relatively small changes in the context in which management is implemented could have substantial impacts on whether these goals are likely to be met. Critically, management can provide substantial conservation benefits to most reefs for fisheries and ecological function, but not biodiversity goals, given their degraded state and the levels of human pressure they face.
Successful implementation of marine conservation plans is largely inhibited by inadequate consideration of the broader social and economic context within which conservation operates. Marine waters ...and their biodiversity are shared by a host of stakeholders, such as commercial fishers, recreational users and offshore developers. Hence, to improve implementation success of conservation plans, we must incorporate other marine activities while explicitly examining trade-offs that may be required. In this study, we test how the inclusion of multiple marine activities can shape conservation plans. We used the entire Mediterranean territorial waters of Israel as a case study to compare four planning scenarios with increasing levels of complexity, where additional zones, threats and activities were added (e.g., commercial fisheries, hydrocarbon exploration interests, aquaculture, and shipping lanes). We applied the marine zoning decision support tool Marxan to each planning scenario and tested a) the ability of each scenario to reach biodiversity targets, b) the change in opportunity cost and c) the alteration of spatial conservation priorities. We found that by including increasing numbers of marine activities and zones in the planning process, greater compromises are required to reach conservation objectives. Complex plans with more activities incurred greater opportunity cost and did not reach biodiversity targets as easily as simplified plans with less marine activities. We discovered that including hydrocarbon data in the planning process significantly alters spatial priorities. For the territorial waters of Israel we found that in order to protect at least 10% of the range of 166 marine biodiversity features there would be a loss of ∼15% of annual commercial fishery revenue and ∼5% of prospective hydrocarbon revenue. This case study follows an illustrated framework for adopting a transparent systematic process to balance biodiversity goals and economic considerations within a country's territorial waters.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of ...reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
During 2012–2013 we surveyed the benthic ctenophore fauna of the Gulf of Aqaba, Red Sea. Four new species, three new records and one known species of benthic ctenophores (family Coeloplanidae) were ...discovered living as episymbionts on various invertebrates and algae: (1)
Coeloplana loyai
n. sp. (on the mushroom corals
Herpolitha limax
Esper, 1797 and
Ctenactis echinata
Pallas, 1766), (2)
Coeloplana yulianicorum
n. sp. (on the soft coral
Sarcophyton glaucum
Quoy and Gaimard, 1833), (3)
Coeloplana huchonae
n. sp. (on the stems of
Dendronephthya hemprichi
Klunzinger, 1877), (4)
Coeloplana fishelsoni
n. sp. (on colonies of
Xenia umbellata
Lamarck, 1816 and
Paralemnalia
Kukenthal, 1913), (5)
Coeloplana punctata
Fricke, 1970 and (6)
Coeloplana lineolata
Fricke, 1970 – both are new records in the Red Sea (found on colonies of
S. glaucum
), (7)
Coeloplana bannwarthi
Krumbach, 1933 on the spines of the sea urchin
Diadema setosum
Leske, 1778, and (8)
Vallicula multiformis
Rankin, 1956, another member of the family, was recorded for the first time from the Red Sea from brown algae,
Sargassum
seaweed and the holothurian
Pearsonothuria graeffei
Semper, 1868. All four new species of benthic ctenophores are different from other known
Coeloplana
species by their host identity, color, and color pattern. The documentation of
V. multiformis
in the Gulf of Aqaba , Red Sea is a remarkable extension of its geographic distribution, which until now was only reported from the Atlantic and Pacific Oceans. These findings demonstrate the great potential of discovering new species of this understudied group, especially in coral reef ecosystems.
Algae are an essential component of healthy coral reefs and serve as the base of the food chain and as a living habitat for numerous organisms. Herbivorous fish play an important role in coral reef ...ecology by mediating competition between fast-growing algae and relatively slow-growing corals. However, because of diving-related difficulties, the importance of herbivory in deep mesophotic coral reefs (30 to 150 m) remains largely unknown. We examined the relationship between herbivores and algae along a depth gradient down to 65 m, and evaluated grazing pressure along the depth gradient. We visually assessed the abundance of herbivorous fish along the depth gradient and estimated fish biomass. We measuredin situturf algae growth rates and performed experimental assessments of grazing pressure using settlement plates and bioassays. We discovered that, while both algal growth and fish density decrease with depth, the decrease in grazing pressure is steeper, with a consumption of <20% of turf-algae production at 65 m versus 40 to 60% at depths of 5 to 20 m. Concomitantly, a decrease in fish biomass and density along the depth gradient reduced potential grazing pressure on macroalgae. Our findings suggest a less important role for herbivorous fish in maintaining algal-free substrate for coral recruitment and growth in deep zones compared with the shallow reef.
Globally, extensive marine areas important for biodiversity conservation and ecosystem functioning are undergoing exploration and extraction of oil and natural gas resources. Such operations are ...expanding to previously inaccessible deep waters and other frontier regions, while conservation‐related legislation and planning is often lacking. Conservation challenges arising from offshore hydrocarbon development are wide‐ranging. These challenges include threats to ecosystems and marine species from oil spills, negative impacts on native biodiversity from invasive species colonizing drilling infrastructure, and increased political conflicts that can delay conservation actions. With mounting offshore operations, conservationists need to urgently consider some possible opportunities that could be leveraged for conservation. Leveraging options, as part of multi‐billion dollar marine hydrocarbon operations, include the use of facilities and costly equipment of the deep and ultra‐deep hydrocarbon industry for deep‐sea conservation research and monitoring and establishing new conservation research, practice, and monitoring funds and environmental offsetting schemes. The conservation community, including conservation scientists, should become more involved in the earliest planning and exploration phases and remain involved throughout the operations so as to influence decision making and promote continuous monitoring of biodiversity and ecosystems. A prompt response by conservation professionals to offshore oil and gas developments can mitigate impacts of future decisions and actions of the industry and governments. New environmental decision support tools can be used to explicitly incorporate the impacts of hydrocarbon operations on biodiversity into marine spatial and conservation plans and thus allow for optimum trade‐offs among multiple objectives, costs, and risks.
Display omitted
•We have simulated virtual oil spills in Israel’s exclusive economic zone.•Realistic ocean and weather conditions were used.•Spills were released near ship routes, mooring buoys, gas ...wells and pipes.•Seasonal oil spill probability maps were created per infrastructure type.•High probability areas were identified and related to ocean and weather patterns.
Recent gas discoveries in the eastern Mediterranean Sea led to multiple operations with substantial economic interest, and with them there is a risk of oil spills and their potential environmental impacts. To examine the potential spatial distribution of this threat, we created seasonal maps of the probability of oil spill pollution reaching an area in the Israeli coastal and exclusive economic zones, given knowledge of its initial sources. We performed simulations of virtual oil spills using realistic atmospheric and oceanic conditions. The resulting maps show dominance of the alongshore northerly current, which causes the high probability areas to be stretched parallel to the coast, increasing contamination probability downstream of source points. The seasonal westerly wind forcing determines how wide the high probability areas are, and may also restrict these to a small coastal region near source points. Seasonal variability in probability distribution, oil state, and pollution time is also discussed.
Descending to the twilight-zone Brokovich, Eran; Einbinder, Shai; Shashar, Nadav ...
Marine ecology. Progress series (Halstenbek),
11/2008, Letnik:
371
Journal Article
Recenzirano
Odprti dostop
In contrast to the abundance of literature on the relationship between fish assemblages and habitat structure in the upper 30 m of coral reefs, the deeper (>40 m) parts of coral reefs are rarely ...studied. We examined changes in reef fish diversity and habitat structure along an increasing depth gradient, including the unknown deep reef. We ran visual and video transects along a substantial depth gradient (0 to 65 m) in the northern Red Sea and extended the known depth distribution for 48 reef species. We found a change in assemblage composition highly correlated to both the depth gradient and a reduction in the abundance of branching corals with depth. The number of reef fish species declined with depth and we also measured a high species turnover as measured by beta diversity (βt, βw) in the deep reef. This pattern is mainly due to the replacement of the abundant damselfishes in the shallow reef, which prey on zooplankton, by zooplanktivorous sea basses and wrasses in the deep reef. The steep reduction in branching corals, which most damselfishes use for cover, may be the main factor contributing to this change. We found a peak in species richness (alpha diversity) at 30 m, a peak in βwat 50 to 65 m, and peaks in βtat 30 to 50 m and 50 to 65 m. The 30 m depth stratum shows species of both shallow and deep assemblages generating a transition zone with characters of both deep and shallow habitats. The fish assemblage continues to change with depth, and future research will determine if there exists a depth threshold at which the assemblage will stabilize.