scholarly journals Gravity of human impacts mediates coral reef conservation gains

2018 ◽  
Vol 115 (27) ◽  
pp. E6116-E6125 ◽  
Author(s):  
Joshua E. Cinner ◽  
Eva Maire ◽  
Cindy Huchery ◽  
M. Aaron MacNeil ◽  
Nicholas A. J. Graham ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Human Impacts ◽  
Global Analysis ◽  
Marine Reserves ◽  
Relative Difference ◽  
Ecosystem Functions ◽  
Fish Biomass ◽  
High Compliance ◽  
Top Predators ◽  
Trade Offs

Coral reefs provide ecosystem goods and services for millions of people in the tropics, but reef conditions are declining worldwide. Effective solutions to the crisis facing coral reefs depend in part on understanding the context under which different types of conservation benefits can be maximized. Our global analysis of nearly 1,800 tropical reefs reveals how the intensity of human impacts in the surrounding seascape, measured as a function of human population size and accessibility to reefs (“gravity”), diminishes the effectiveness of marine reserves at sustaining reef fish biomass and the presence of top predators, even where compliance with reserve rules is high. Critically, fish biomass in high-compliance marine reserves located where human impacts were intensive tended to be less than a quarter that of reserves where human impacts were low. Similarly, the probability of encountering top predators on reefs with high human impacts was close to zero, even in high-compliance marine reserves. However, we find that the relative difference between openly fished sites and reserves (what we refer to as conservation gains) are highest for fish biomass (excluding predators) where human impacts are moderate and for top predators where human impacts are low. Our results illustrate critical ecological trade-offs in meeting key conservation objectives: reserves placed where there are moderate-to-high human impacts can provide substantial conservation gains for fish biomass, yet they are unlikely to support key ecosystem functions like higher-order predation, which is more prevalent in reserve locations with low human impacts.

scholarly journals A long-term, spatially replicated experimental test of the effect of marine reserves on local fish yields

2005 ◽  
Vol 62 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Angel C Alcala ◽  
Garry R Russ ◽  
Aileen P Maypa ◽  
Hilconida P Calumpong
Keyword(s):  
Coral Reefs ◽  
Experimental Test ◽  
Marine Reserves ◽  
Fish Biomass ◽  
Total Catch ◽  
Target Fish ◽  
Fish Yields

Do no-take marine reserves affect fishery yields? Manipulations of reserve status, and yield estimates, were made at two Philippine islands over two decades. Twenty-five percent and ten percent, respectively, of the coral reefs at Sumilon and Apo islands were made no-take reserves in 1974 and 1982. Biomass of target fish increased inside the no-take reserves 3- to 4.5-fold over 9–18 years. Biomass did not increase outside each reserve. Protection of the Sumilon reserve ceased in 1984. Biomass of targeted fish in the reserve and trap and gillnet catches of these fish declined by 42.7% and 40%, respectively, by 1985. The reserve was reprotected from 1987 to 1991 and from 1995 to 2001. Fish biomass increased in the reserve by 27.2%. Trap and gillnet catches outside the reserve increased 26.9% by 2001. The Apo reserve was protected from 1982 to 2001. Total catch of major fish families was significantly higher after (1985–2001) than before (1981) reserve establishment at Apo, increasing 41.3% between 1981 and 1998–2001. These experiments, plus spillover evidence, suggest that marine reserves may help maintain, or even enhance, local fishery yields in the long-term.

scholarly journals Reconstructing baselines for Caribbean predatory reef fishes

2015 ◽  
Author(s):  
Abel Valdivia ◽  
Courtney Cox ◽  
John Bruno
Keyword(s):  
Reef Fish ◽  
Human Impacts ◽  
Marine Reserves ◽  
Reef Fishes ◽  
Explanatory Models ◽  
Coastal Development ◽  
Predatory Fish ◽  
Fish Biomass ◽  
Mixed Effect ◽  
Natural Factors

The natural, pre-human, abundance of most large predators is unknown due to the lack of historical data and the poor understanding of the natural factors that control their populations. We assessed the relationship between the biomass of predatory reef fishes and several anthropogenic and environmental variables to (1) predict among site variability in predator abundance in response to both human impacts and natural factors, and (2) estimate historical baselines of fish predator biomass in the absence of humans. We hypothesized that predatory fish abundance declines with human influence but is also strongly associated with natural environmental variability. We assessed the biomass structure of reef fishes at 39 sites over three years across the greater Caribbean. Using generalized linear mixed effect models, we examined the relationships between the biomass of predatory reef fishes and a comprehensive set of 29 anthropogenic, physical, spatial, biotic, and management-related covariates. We used the best explanatory models to predict the biomass of fish predators in the absence of humans. Predatory reef fish biomass was higher in marine reserves but strongly negatively related to human impacts, especially coastal development. Over 50% of the variability in predator biomass, however, was also explained by non-human factors including reef complexity, ocean productivity, and prey abundance. Comparing site-specific predicted values to field observations suggests predatory reef fish biomass has declined by 80-95% in most sites, even within most marine reserves. Bottom-up forces are critical (yet often overlooked) drivers of reef fish communities across gradients of human exploitation. This suggests that we could underestimate historical biomass at sites that provide ideal conditions for predators or greatly overestimate that of seemingly predator-depleted sites that may have never supported large predator populations due to suboptimal environmental conditions. We highlight areas that are natural “hot spots” of predator biomass that can be targeted for strategic protection and restoration.

scholarly journals The importance of sponges and mangroves in supporting fish communities in degraded coral reefs in Caribbean Panama

2017 ◽  
Author(s):  
Janina Seemann ◽  
Alexandra Yingst ◽  
Rick D Stuart-Smith ◽  
Graham J Edgar ◽  
Andrew H Altieri
Keyword(s):  
Coral Reefs ◽  
Fish Community ◽  
Trophic Structure ◽  
Habitat Degradation ◽  
Human Impacts ◽  
Small Body ◽  
Fish Communities ◽  
Trophic Levels ◽  
Fish Biomass ◽  
Total Fish

Fish communities associated with coral reefs worldwide are threatened by overexploitation and other human impacts such as bleaching events that cause habitat degradation. We assessed the fish community on coral reefs on the Caribbean coast of Panama, as well as those associated with mangrove and seagrass habitats, to explore the influences of habitat cover, connectivity and environmental characteristics in sustaining biomass, richness and trophic structure in a degraded tropical ecosystem. Overall, 94 % of all fishes across all habitat types were of small body size (≤11 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Moreover, total fish biomass was very low, small fishes from low trophic levels were over-represented, and top predators were under-represented relative to other Caribbean reefs. For example, herbivorous/omnivorous/detrivorous fishes (trophic level 2-2.7) comprised 37 % of total fish biomass, with the diminutive parrotfish Scarus iseri comprising 72 % of the parrotfish biomass. However, the abundance of sponges and proximity of mangroves were found to be important positive drivers of reef fish richness, biomass and trophic structure on a given reef, presumably by promoting functional processes of ecosystems. The masked goby (Coryphopterus personata) was a strong indicator of reef degradation, apparently benefiting from the reduced density of large predators on local reefs. The damselfish Abudefduf saxatilis was more common on reefs with high sponge cover, and also to proximity to mangroves. Our study suggests that a diverse fish community can persist on degraded coral reefs, and that the availability of habitat forming organisms other than corals, including sponges and mangroves, and their arrangement on the landscape, is critical to the maintenance of functional processes in these ecosystems.

scholarly journals Reconstructing baselines for Caribbean predatory reef fishes

2015 ◽  
Author(s):  
Abel Valdivia ◽  
Courtney Cox ◽  
John Bruno
Keyword(s):  
Reef Fish ◽  
Human Impacts ◽  
Marine Reserves ◽  
Reef Fishes ◽  
Explanatory Models ◽  
Coastal Development ◽  
Predatory Fish ◽  
Fish Biomass ◽  
Mixed Effect ◽  
Natural Factors

The natural, pre-human, abundance of most large predators is unknown due to the lack of historical data and the poor understanding of the natural factors that control their populations. We assessed the relationship between the biomass of predatory reef fishes and several anthropogenic and environmental variables to (1) predict among site variability in predator abundance in response to both human impacts and natural factors, and (2) estimate historical baselines of fish predator biomass in the absence of humans. We hypothesized that predatory fish abundance declines with human influence but is also strongly associated with natural environmental variability. We assessed the biomass structure of reef fishes at 39 sites over three years across the greater Caribbean. Using generalized linear mixed effect models, we examined the relationships between the biomass of predatory reef fishes and a comprehensive set of 29 anthropogenic, physical, spatial, biotic, and management-related covariates. We used the best explanatory models to predict the biomass of fish predators in the absence of humans. Predatory reef fish biomass was higher in marine reserves but strongly negatively related to human impacts, especially coastal development. Over 50% of the variability in predator biomass, however, was also explained by non-human factors including reef complexity, ocean productivity, and prey abundance. Comparing site-specific predicted values to field observations suggests predatory reef fish biomass has declined by 80-95% in most sites, even within most marine reserves. Bottom-up forces are critical (yet often overlooked) drivers of reef fish communities across gradients of human exploitation. This suggests that we could underestimate historical biomass at sites that provide ideal conditions for predators or greatly overestimate that of seemingly predator-depleted sites that may have never supported large predator populations due to suboptimal environmental conditions. We highlight areas that are natural “hot spots” of predator biomass that can be targeted for strategic protection and restoration.

scholarly journals The importance of sponges and mangroves in supporting fish communities in degraded coral reefs in Caribbean Panama

2017 ◽  
Author(s):  
Janina Seemann ◽  
Alexandra Yingst ◽  
Rick D Stuart-Smith ◽  
Graham J Edgar ◽  
Andrew H Altieri
Keyword(s):  
Coral Reefs ◽  
Fish Community ◽  
Trophic Structure ◽  
Habitat Degradation ◽  
Human Impacts ◽  
Small Body ◽  
Fish Communities ◽  
Trophic Levels ◽  
Fish Biomass ◽  
Total Fish

Fish communities associated with coral reefs worldwide are threatened by overexploitation and other human impacts such as bleaching events that cause habitat degradation. We assessed the fish community on coral reefs on the Caribbean coast of Panama, as well as those associated with mangrove and seagrass habitats, to explore the influences of habitat cover, connectivity and environmental characteristics in sustaining biomass, richness and trophic structure in a degraded tropical ecosystem. Overall, 94 % of all fishes across all habitat types were of small body size (≤11 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Moreover, total fish biomass was very low, small fishes from low trophic levels were over-represented, and top predators were under-represented relative to other Caribbean reefs. For example, herbivorous/omnivorous/detrivorous fishes (trophic level 2-2.7) comprised 37 % of total fish biomass, with the diminutive parrotfish Scarus iseri comprising 72 % of the parrotfish biomass. However, the abundance of sponges and proximity of mangroves were found to be important positive drivers of reef fish richness, biomass and trophic structure on a given reef, presumably by promoting functional processes of ecosystems. The masked goby (Coryphopterus personata) was a strong indicator of reef degradation, apparently benefiting from the reduced density of large predators on local reefs. The damselfish Abudefduf saxatilis was more common on reefs with high sponge cover, and also to proximity to mangroves. Our study suggests that a diverse fish community can persist on degraded coral reefs, and that the availability of habitat forming organisms other than corals, including sponges and mangroves, and their arrangement on the landscape, is critical to the maintenance of functional processes in these ecosystems.

scholarly journals Measuring Sound at a Cold-Water Coral Reef to Assess the Impact of COVID-19 on Noise Pollution

2021 ◽  
Vol 8 ◽  
Author(s):  
Laurence H. De Clippele ◽  
Denise Risch
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Level ◽  
Cold Water ◽  
Noise Pollution ◽  
Ecosystem Functions ◽  
Noise Levels ◽  
Level Height ◽  
Water Coral

This study compares the noise levels at the cold-water coral Tisler reef, before and after the closure of the border between Norway and Sweden, which occurred as a direct result of the COVID-19 pandemic. The Tisler reef is a marine protected area located under a ferry “highway” that connects Norway and Sweden. Cold-water coral reefs are recognised as being important hotspots of both biodiversity and biomass, they function as breeding and nursing grounds for commercially important fish and are essential in providing ecosystem functions. Whilst studies have shown that fishery, ocean warming, and acidification threaten them, the effects of noise pollution on cold-water coral reefs remains unstudied. To study the severity of noise pollution at the Tisler reef, a long-term acoustic recorder was deployed from 29 January 2020 until 26 May 2020. From 15 March COVID-19 lockdown measures stopped passenger vessel traffic between Norway and Sweden. This study found that the overall noise levels were significantly lower after border closure, due to reduced ferry traffic, wind speeds, and sea level height. When comparing the median hourly noise levels of before vs. after border closure, this study measured a significant reduction in the 63–125 Hz 1/3 octave band noise levels of 8.94 ± 0.88 (MAD) dB during the day (07:00:00–19:59:59) and 1.94 ± 0.11 (MAD) dB during the night (20:00:00–06:59:59). Since there was no ferry traffic during the night, the drop in noise levels at night was likely driven by seasonal changes, i.e., the reduction in wind speed and sea level height when transitioning from winter to spring. Taking into account this seasonal effect, it can be deduced that the COVID-19 border closure reduced the noise levels in the 63–125 Hz 1/3 octave bands at the Tisler reef by 7.0 ± 0.99 (MAD) dB during the day. While the contribution of, and changes in biological, weather-related and geophysical sound sources remain to be assessed in more detail, understanding the extent of anthropogenic noise pollution at the Tisler cold-water coral reef is critical to guide effective management to ensure the long-term health and conservation of its ecosystem functions.

scholarly journals Moving to 3D: relationships between coral planar area, surface area and volume

2016 ◽  
Author(s):  
Jenny E House ◽  
Luc M Bidaut ◽  
Alec P Christie ◽  
Oscar Pizarro ◽  
Maria Dornelas
Keyword(s):  
Coral Reefs ◽  
Surface Area ◽  
Coral Cover ◽  
Marine Ecosystem ◽  
Ecosystem Functions ◽  
Reef Corals ◽  
Technological Developments ◽  
Planar Area ◽  
2D And 3D ◽  
Area And Volume

Coral reefs are a valuable and vulnerable marine ecosystem. The structure of coral reefs influences their health and ability to fulfill ecosystem functions and services. However, monitoring reef corals largely relies on 1D or 2D estimates of coral cover and abundance that overlook change in ecologically significant aspects of the reefs because they do not incorporate vertical or volumetric information. This study explores the relationship between 2D and 3D metrics of coral size. We show that surface area and volume scale consistently with planar area, albeit with morphotype specific conversion parameters. We use a photogrammetric approach using open-source software to estimate the ability of photogrammetry to provide measurement estimates of corals in 3D. Technological developments have made photogrammetry a valid and practical technique for studying coral reefs. We anticipate that these techniques for moving coral research from 2D into 3D will facilitate answering ecological questions by incorporating the 3rd dimension into monitoring.

scholarly journals Coral species composition drives key ecosystem function on coral reefs

2020 ◽  
Vol 287 (1921) ◽  
pp. 20192214 ◽  
Author(s):  
Laura E. Richardson ◽  
Nicholas A. J. Graham ◽  
Andrew S. Hoey
Keyword(s):  
Coral Reefs ◽  
Species Composition ◽  
Coral Species ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Ecosystem Functions ◽  
Algal Turf ◽  
Benthic Assemblages ◽  
Ecosystem Recovery ◽  
Visual Occlusion

Rapid and unprecedented ecological change threatens the functioning and stability of ecosystems. On coral reefs, global climate change and local stressors are reducing and reorganizing habitat-forming corals and associated species, with largely unknown implications for critical ecosystem functions such as herbivory. Herbivory mediates coral–algal competition, thereby facilitating ecosystem recovery following disturbance such as coral bleaching events or large storms. However, relationships between coral species composition, the distribution of herbivorous fishes and the delivery of their functional impact are not well understood. Here, we investigate how herbivorous fish assemblages and delivery of two distinct herbivory processes, grazing and browsing, differ among three taxonomically distinct, replicated coral habitats. While grazing on algal turf assemblages was insensitive to different coral configurations, browsing on the macroalga Laurencia cf. obtusa varied considerably among habitats, suggesting that different mechanisms may shape these processes. Variation in browsing among habitats was best predicted by the composition and structural complexity of benthic assemblages (in particular the cover and composition of corals, but not macroalgal cover), and was poorly reflected by visual estimates of browser biomass. Surprisingly, the lowest browsing rates were recorded in the most structurally complex habitat, with the greatest cover of coral (branching Porites habitat). While the mechanism for the variation in browsing is not clear, it may be related to scale-dependent effects of habitat structure on visual occlusion inhibiting foraging activity by browsing fishes, or the relative availability of alternate dietary resources. Our results suggest that maintained functionality may vary among distinct and emerging coral reef configurations due to ecological interactions between reef fishes and their environment determining habitat selection.

scholarly journals The evolution of traits and functions in herbivorous coral reef fishes through space and time

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182672 ◽  
Author(s):  
Alexandre C. Siqueira ◽  
David R. Bellwood ◽  
Peter F. Cowman
Keyword(s):  
Coral Reefs ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Ecosystem Functions ◽  
Ecological Framework ◽  
Functional Composition ◽  
Ecological Process ◽  
Wide Range ◽  
The World ◽  
Trait Space

Herbivory by fishes has been identified as a key ecological process shaping coral reefs through time. Although taxonomically limited, herbivorous reef fishes display a wide range of traits, which results in varied ecosystem functions on reefs around the world. Yet, we understand little about how these trait combinations and functions in ecosystems changed through time and across biogeographic realms. Here, we used fossils and phylogenies in a functional ecological framework to reveal temporal changes in nominally herbivorous fish assemblages among oceanic basins in both trait space and lineage richness among functions. We show that the trait space occupied by extant herbivorous fishes in the Indo-Pacific resulted from an expansion of traits from the ancestral Tethyan assemblages. By contrast, trait space in the Atlantic is the result of lineage turnover, with relatively recent colonization by lineages that arose in the east Tethys/Indo-Pacific. From an ecosystem function perspective, the Atlantic supports a depauperate fauna, with few extant herbivorous reef fish lineages performing each function. Indo-Pacific fishes support both more functions and more lineages within each function, with a marked Miocene to Pleistocene expansion. These disparities highlight the importance of history in explaining global variation in fish functional composition on coral reefs.

scholarly journals Nutrient pollution disrupts key ecosystem functions on coral reefs

2018 ◽  
Vol 285 (1880) ◽  
pp. 20172718 ◽  
Author(s):  
Nyssa J. Silbiger ◽  
Craig E. Nelson ◽  
Kristina Remple ◽  
Jessica K. Sevilla ◽  
Zachary A. Quinlan ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Nutrient Addition ◽  
Ecosystem Functions ◽  
Nutrient Pollution ◽  
Global Changes ◽  
Ambient Conditions ◽  
Net Community Production ◽  
Saturation State ◽  
Indirect Response ◽  
The Impact

There is a long history of examining the impacts of nutrient pollution and pH on coral reefs. However, little is known about how these two stressors interact and influence coral reef ecosystem functioning. Using a six-week nutrient addition experiment, we measured the impact of elevated nitrate (NO − 3 ) and phosphate (PO 3− 4 ) on net community calcification (NCC) and net community production (NCP) rates of individual taxa and combined reef communities. Our study had four major outcomes: (i) NCC rates declined in response to nutrient addition in all substrate types, (ii) the mixed community switched from net calcification to net dissolution under medium and high nutrient conditions, (iii) nutrients augmented pH variability through modified photosynthesis and respiration rates, and (iv) nutrients disrupted the relationship between NCC and aragonite saturation state documented in ambient conditions. These results indicate that the negative effect of NO − 3 and PO 3− 4 addition on reef calcification is likely both a direct physiological response to nutrients and also an indirect response to a shifting pH environment from altered NCP rates. Here, we show that nutrient pollution could make reefs more vulnerable to global changes associated with ocean acidification and accelerate the predicted shift from net accretion to net erosion.

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