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Understanding how natural communities and ecosystems are structured and respond to anthropogenic pressures in a rapidly changing world is key to successful management and conservation. A fundamental but often overlooked biological characteristic of organisms is sex. Sex-based responses are often considered when conducting studies at organismal and population levels, but are rarely investigated in community ecology. Focusing on kelp forests as a model system, and through a review of other marine and terrestrial ecosystems, we found evidence of widespread sex-based variation in species interactions. Sex-based variation in species interactions is expected to affect ecosystem structure and functioning via multiple trophic and nontrophic pathways. Understanding the drivers and consequences of sex-based variation in species interactions can inform more effective management and restoration.
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Many coastal marine species have discontinuous distributions or genetic breakpoints throughout their geographical ranges. These spatial and genetic disjunctions occur in species that span limited to broad dispersal potential. Thus, the mechanisms that underlie these disjunctions remain speculative or incompletely known, particularly on small spatial scales where long-term historical processes are unlikely to be the only mechanism contributing to disjunction. Rather, ecological or oceanographic factors may be important. To identify key drivers of coastal disjunctions, we reviewed publications investigating spatial and genetic disjunctions in coastal marine species and visually summarized where and why they are thought to occur. The most frequently cited mechanisms implicated in causing disjunctions include historical processes, oceanographic features, heterogeneous habitat, species introductions, and limited larval dispersal capacities. However, the relative importance of each of these processes varies depending on the spatial scales investigated. Furthermore, locations associated with disjunctions for a suite of species are typically associated with multiple processes that maintain these disjunctions. This study provides a non-exhaustive synthesis of disjunctions in coastal marine species by visualizing where they occur, exploring underlying mechanisms, and investigating biases in how the scientific community studies this phenomenon.
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Direct exploitation through fishing is driving dramatic declines of wildlife populations in ocean environments, particularly for predatory and large-bodied taxa. Despite wide recognition of this pattern and well-established consequences of such trophic downgrading on ecosystem function, there have been few empirical studies examining the effects of fishing on whole system trophic architecture. Understanding these kinds of structural impacts is especially important in coral reef ecosystems-often heavily fished and facing multiple stressors. Given the often high dietary flexibility and numerous functional redundancies in diverse ecosystems such as coral reefs, it is important to establish whether web architecture is strongly impacted by fishing pressure or whether it might be resilient, at least to moderate-intensity pressure. To examine this question, we used a combination of bulk and compound-specific stable isotope analyses measured across a range of predatory and low-trophic-level consumers between two coral reef ecosystems that differed with respect to fishing pressure but otherwise remained largely similar. We found that even in a high-diversity system with relatively modest fishing pressure, there were strong reductions in the trophic position (TP) of the three highest TP consumers examined in the fished system but no effects on the TP of lower-level consumers. We saw no evidence that this shortening of the affected food webs was being driven by changes in basal resource consumption, for example, through changes in the spatial location of foraging by consumers. Instead, this likely reflected internal changes in food web architecture, suggesting that even in diverse systems and with relatively modest pressure, human harvest causes significant compressions in food chain length. This observed shortening of these food webs may have many important emergent ecological consequences for the functioning of ecosystems impacted by fishing or hunting. Such important structural shifts may be widespread but unnoticed by traditional surveys. This insight may also be useful for applied ecosystem managers grappling with choices about the relative importance of protection for remote and pristine areas and the value of strict no-take areas to protect not just the raw constituents of systems affected by fishing and hunting but also the health and functionality of whole systems.
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Recifes de Corais , Peixes , Cadeia Alimentar , Animais , Peixes/fisiologia , Pesqueiros , Isótopos de Carbono/análise , Conservação dos Recursos Naturais , Isótopos de Nitrogênio/análiseRESUMO
Global environmental change drives diversity loss and shifts in community structure. A key challenge is to better understand the impacts on ecosystem function and to connect species and trait diversity of assemblages with ecosystem properties that are in turn linked to ecosystem functioning. Here we quantify shifts in species composition and trait diversity associated with ocean acidification (OA) by using field measurements at marine CO2 vent systems spanning four reef habitats across different depths in a temperate coastal ecosystem. We find that both species and trait diversity decreased, and that ecosystem properties (understood as the interplay between species, traits, and ecosystem function) shifted with acidification. Furthermore, shifts in trait categories such as autotrophs, filter feeders, herbivores, and habitat-forming species were habitat-specific, indicating that OA may produce divergent responses across habitats and depths. Combined, these findings reveal the importance of connecting species and trait diversity of marine benthic habitats with key ecosystem properties to anticipate the impacts of global environmental change. Our results also generate new insights on the predicted general and habitat-specific ecological consequences of OA.
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Ecossistema , Água do Mar , Água do Mar/química , Concentração de Íons de Hidrogênio , Acidificação dos Oceanos , Dióxido de CarbonoRESUMO
Seascape genomics gives insight into the geographic and environmental factors shaping local adaptations. It improves the understanding of the potential effects of climate change, which is relevant to provide the basis for the international management of fishery resources. The pink abalone (Haliotis corrugata) is distributed from California, United States to Baja California Sur, Mexico, exposed to a latitudinal environmental gradient in the California Current System. Management of the pink abalone contrasts between Mexico and the United States; Mexico has an active fishery organized in four administrative areas, while the United States has kept the fishery in permanent closure since 1996. However, the impact of environmental factors on genetic variation along the species distribution remains unknown, and understanding this relationship is crucial for effective spatial management strategies. This study aims to investigate the neutral and adaptive genomic structure of H. corrugata. A total of 203 samples from 13 locations were processed using ddRADseq, and covering the species' distribution. Overall, 2,231 neutral, nine potentially adaptive and three genomic-environmental association loci were detected. The neutral structure identified two groups: 1) California, United States and 2) Baja California Peninsula, México. In addition, the adaptive structure analysis also detected two groups with genetic divergence observed at Punta Eugenia. Notably, the seawater temperature significantly correlated with the northern group (temperate) and the southern (warmer) group. This study is a valuable foundation for future research and conservation initiatives, emphasizing the importance of considering neutral and adaptive genetic factors when developing management strategies for marine species.
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Gastrópodes , Animais , México , Genômica , Deriva Genética , Água do MarRESUMO
Ecosystems around the world are continuously undergoing recovery from anthropogenic disturbances like climate change, overexploitation, and habitat destruction. Coral reefs are a prime example of a threatened ecosystem and coral recruitment is a critical component of reef recovery from disturbances. Reef fishes structure this recruitment by directly consuming macroalgae and coral recruits or by indirectly altering the substrate to facilitate coral settlement (e.g., grazing scars). However, how these direct and indirect mechanisms vary through time remains largely unknown. Here, we quantified coral recruitment on settlement tiles with divots that mimic grazing scars and caging treatments to exclude or allow fish feeding over 3 years at Palmyra Atoll in the Pacific Ocean. We found that the positive and negative effects of fishes on coral recruitment varies through time. After 3 years, both grazing scars and fish grazing no longer predicted coral recruitment, suggesting that the role of fishes decreases over time. Our results emphasize that reef fish populations are important in promoting initial coral recovery after disturbances. However, over time, factors like the environment may become more important. Future work should continue to explore how the strength and direction of top-down control by consumers varies through time across multiple ecosystems.
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Antozoários , Animais , Ecossistema , Cicatriz , Recifes de Corais , PeixesRESUMO
Consumers play an integral role in mediating ecological succession-the change in community composition over time. As consumer populations are facing rapid decline in ecosystems around the world, understanding of their ecological role is becoming increasingly urgent. Increased understanding of how changes in consumer populations may influence community variability across space and turnover through time during succession is particularly important for coral reefs, which are among the most threatened ecosystems globally, and where fishes play vital roles in structuring benthic succession. Here, we examine how consumers influence coral reef succession by deploying 180 paired settlement tiles, caged (to exclude fishes larger than approximately 15 cm) and uncaged, within Palmyra Atoll, a remote marine wildlife refuge with previously documented high fish abundance, and monitored benthic community development one and three years after deployment. We found that excluding large fishes lead to lower alpha diversity and divergent community states across space (i.e.,, high beta diversity among caged tiles), suggesting that benthic fish feeding maintains local diversity but tends to homogenize community composition with dominance by crustose coralline algae. In addition, when fish were experimentally excluded, the developing benthic community exhibited a greater change in species composition over time (i.e., high temporal beta diversity), indicating that fish feeding tends to canalize community successional trajectories. Finally, the caged and uncaged tiles became more similar over time, suggesting that fish feeding plays a more important role during early succession. Our results demonstrate that the loss of large fishes, for example from overfishing, may result in benthic communities that are more variable across space and time. Increased variability could have important implications for ecosystem function and coral reef resilience in the face of escalating global stressors.
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Antozoários , Recifes de Corais , Animais , Ecossistema , Conservação dos Recursos Naturais , Pesqueiros , PeixesRESUMO
In an ocean that is rapidly warming and losing oxygen, accurate forecasting of species' responses must consider how this environmental change affects fundamental aspects of their physiology. Here, we develop an absolute metabolic index (ΦA) that quantifies how ocean temperature, dissolved oxygen and organismal mass interact to constrain the total oxygen budget an organism can use to fuel sustainable levels of aerobic metabolism. We calibrate species-specific parameters of ΦA with physiological measurements for red abalone (Haliotis rufescens) and purple urchin (Strongylocentrotus purpuratus). ΦA models highlight that the temperature where oxygen supply is greatest shifts cooler when water loses oxygen or organisms grow larger, providing a mechanistic explanation for observed thermal preference patterns. Viable habitat forecasts are disproportionally deleterious for red abalone, revealing how species-specific physiologies modulate the intensity of a common climate signal, captured in the newly developed ΦA framework.
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Gastrópodes , Oxigênio , Animais , Oxigênio/metabolismo , Água , Temperatura , Clima , Mudança Climática , Oceanos e Mares , Aquecimento GlobalRESUMO
Blue foods, sourced in aquatic environments, are important for the economies, livelihoods, nutritional security and cultures of people in many nations. They are often nutrient rich1, generate lower emissions and impacts on land and water than many terrestrial meats2, and contribute to the health3, wellbeing and livelihoods of many rural communities4. The Blue Food Assessment recently evaluated nutritional, environmental, economic and justice dimensions of blue foods globally. Here we integrate these findings and translate them into four policy objectives to help realize the contributions that blue foods can make to national food systems around the world: ensuring supplies of critical nutrients, providing healthy alternatives to terrestrial meat, reducing dietary environmental footprints and safeguarding blue food contributions to nutrition, just economies and livelihoods under a changing climate. To account for how context-specific environmental, socio-economic and cultural aspects affect this contribution, we assess the relevance of each policy objective for individual countries, and examine associated co-benefits and trade-offs at national and international scales. We find that in many African and South American nations, facilitating consumption of culturally relevant blue food, especially among nutritionally vulnerable population segments, could address vitamin B12 and omega-3 deficiencies. Meanwhile, in many global North nations, cardiovascular disease rates and large greenhouse gas footprints from ruminant meat intake could be lowered through moderate consumption of seafood with low environmental impact. The analytical framework we provide also identifies countries with high future risk, for whom climate adaptation of blue food systems will be particularly important. Overall the framework helps decision makers to assess the blue food policy objectives most relevant to their geographies, and to compare and contrast the benefits and trade-offs associated with pursuing these objectives.
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Organismos Aquáticos , Segurança Alimentar , Internacionalidade , Alimentos Marinhos , Desenvolvimento Sustentável , Humanos , Dieta/métodos , Dieta/estatística & dados numéricos , Dieta/tendências , Meio Ambiente , Carne , Estado Nutricional , Internacionalidade/legislação & jurisprudência , Alimentos Marinhos/economia , Alimentos Marinhos/estatística & dados numéricos , Alimentos Marinhos/provisão & distribuição , Desenvolvimento Sustentável/economia , Desenvolvimento Sustentável/legislação & jurisprudência , Desenvolvimento Sustentável/tendências , Segurança Alimentar/economia , Segurança Alimentar/legislação & jurisprudência , Segurança Alimentar/métodos , Mudança Climática , Política de Saúde , Política Ambiental , Fatores Socioeconômicos , Características Culturais , Ácidos Graxos Ômega-3 , Pegada de Carbono , Doenças Cardiovasculares/epidemiologiaRESUMO
Anthropogenic stressors are predicted to alter biodiversity and ecosystem functioning worldwide. However, scaling up from species to ecosystem responses poses a challenge, as species and functional groups can exhibit different capacities to adapt, acclimate, and compensate under changing environments. We used a naturally acidified seagrass ecosystem (the endemic Mediterranean Posidonia oceanica) as a model system to examine how ocean acidification (OA) modifies the community structure and functioning of plant detritivores, which play vital roles in the coastal nutrient cycling and food web dynamics. In seagrass beds associated with volcanic CO2 vents (Ischia, Italy), we quantified the effects of OA on seagrass decomposition by deploying litterbags in three distinct pH zones (i.e., ambient, low, extreme low pH), which differed in the mean and variability of seawater pH. We replicated the study in two discrete vents for 117 days (litterbags sampled on day 5, 10, 28, 55, and 117). Acidification reduced seagrass detritivore richness and diversity through the loss of less abundant, pH-sensitive species but increased the abundance of the dominant detritivore (amphipod Gammarella fucicola). Such compensatory shifts in species abundance caused more than a threefold increase in the total detritivore abundance in lower pH zones. These community changes were associated with increased consumption (52%-112%) and decay of seagrass detritus (up to 67% faster decomposition rate for the slow-decaying, refractory detrital pool) under acidification. Seagrass detritus deployed in acidified zones showed increased N content and decreased C:N ratio, indicating that altered microbial activities under OA may have affected the decay process. The findings suggest that OA could restructure consumer assemblages and modify plant decomposition in blue carbon ecosystems, which may have important implications for carbon sequestration, nutrient recycling, and trophic transfer. Our study highlights the importance of within-community response variability and compensatory processes in modulating ecosystem functions under extreme global change scenarios.
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Alismatales , Ecossistema , Dióxido de Carbono , Concentração de Íons de Hidrogênio , Água do Mar/químicaRESUMO
Although parasites are ubiquitous in marine ecosystems, predicting the abundance of parasites present within marine ecosystems has proven challenging due to the unknown effects of multiple interacting environmental gradients and stressors. Furthermore, parasites often are considered as a uniform group within ecosystems despite their significant diversity. We aim to determine the potential importance of multiple predictors of parasite abundance in coral reef ecosystems, including reef area, island area, human population density, chlorophyll-a, host diversity, coral cover, host abundance and island isolation. Using a model selection approach within a database of more than 1,200 individual fish hosts and their parasites from 11 islands within the Pacific Line Islands archipelago, we reveal that geographic gradients, including island area and island isolation, emerged as the best predictors of parasite abundance. Life history moderated the relationship; parasites with complex life cycles increased in abundance with increasing island isolation, while parasites with direct life cycles decreased with increasing isolation. Direct life cycle parasites increased in abundance with increasing island area, although complex life cycle parasite abundance was not associated with island area. This novel analysis of a unique dataset indicates that parasite abundance in marine systems cannot be predicted precisely without accounting for the independent and interactive effects of each parasite's life history and environmental conditions.
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Parasitos , Animais , Recifes de Corais , Ecossistema , Peixes/parasitologia , Interações Hospedeiro-Parasita , Estágios do Ciclo de VidaRESUMO
Resilience of food systems is key to ensuring food security through crisis. The COVID-19 pandemic presents an unprecedented shock that reveals varying levels of resilience of increasingly interconnected food systems across the globe. We contribute to the ongoing debate about whether increased connectivity reduces or enhances resilience in the context of rural Pacific food systems, while examining how communities have adapted to the global shocks associated with the pandemic to ensure food security. We conducted 609 interviews across 199 coastal villages from May to October 2020 in Federated States of Micronesia, Fiji, Palau, Papua New Guinea, Solomon Islands, Tonga, and Tuvalu to understand community-level impacts and adaptations during the first 5-10 months of the COVID-19 crisis. We found that local food production practices and food sharing conferred resilience, and that imported foods could aid or inhibit resilience. Communities in countries more reliant on imports were almost twice as likely to report food insecurity compared to those least reliant. However, in places dealing with a concurrent cyclone, local food systems were impaired, and imported foods proved critical. Our findings suggest that policy in the Pacific should bolster sustainable local food production and practices. Pacific states should avoid becoming overly reliant on food imports, while having measures in place to support food security after disasters, supplementing locally produced and preserved foods with imported foods when necessary. Developing policies that promote resilient food systems can help prepare communities for future shocks, including those anticipated with climate change.
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The dataset presented in this article contains information about marine Area-Based Management Tools (ABMTs) used to assess their contribution to the United Nations 2030 Sustainable Development Goals. Following the scope of the analysis, ABMTs were identified by scrutinizing international and regional legal sources related to ocean management in the fields of marine conservation, fisheries, deep sea bed mining, underwater natural and cultural heritage, environmental conservation, and marine spatial planning. Legal sources were screened to depict the following characteristics of individual ABMTs: i) management objectives; ii) authorities responsible for delivering such objectives; iii) the system of management and planning entailed in the ABMT including the zoning type; and iv) the specific spatial scope and domain each ABMT refer to in vertical depth and horizontal domain. Data were generated through an internal expert elicitation. Experts, initially trained in the data analysis and related protocol, contributed to the data production because of their specific knowledge and experience in ocean management. This dataset represents a unique source of information for advancing research about monitoring and assessment of the achievement of sustainable development goals that encompasses different types of ABMTs.
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Global stressors are increasingly altering ecosystem resistance, resilience, and functioning by reorganizing vital species interactions. However, our predictive understanding of these changes is hindered by failures to consider species-specific functional roles and stress responses within communities. Stressor-driven loss or reduced performance of strongly interacting species may generate abrupt shifts in ecosystem states and functions. Yet, empirical support for this prediction is scarce, especially in marine climate change research. Using a marine assemblage comprising a habitat-forming seagrass (Phyllospadix torreyi), its algal competitor, and three consumer species (algal grazers) with potentially different functional roles and pH tolerance, we investigated how ocean acidification (OA) may, directly and indirectly, alter community resistance. In the field and laboratory, hermit crabs (Pagurus granosimanus and P. hirsutiusculus) and snails (Tegula funebralis) displayed distinct microhabitat use, with hermit crabs more frequently grazing in the area of high algal colonization (i.e., surfgrass canopy). In mesocosms, this behavioral difference led to hermit crabs exerting ~2 times greater per capita impact on algal epiphyte biomass than snails. Exposure to OA variably affected the grazers: snails showed reduced feeding and growth under extreme pH (7.3 and 7.5), whereas hermit crabs (P. granosimanus) maintained a similar grazing rate under all pH levels (pH 7.3, 7.5, 7.7, and 7.95). Epiphyte biomass increased more rapidly under extreme OA (pH 7.3 and 7.5), but natural densities of snails and hermit crabs prevented algal overgrowth irrespective of pH treatments. Finally, grazers and acidification additively increased surfgrass productivity and delayed the shoot senescence. Hence, although OA impaired the function of the most abundant consumers (snails), strongly interacting and pH-tolerant species (hermit crabs) largely maintained the top-down pressure to facilitate seagrass dominance. Our study highlights significant within-community variation in species functional and response traits and shows that this variation has important ecosystem consequences under anthropogenic stressors.
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Ecossistema , Água do Mar , Efeitos Antropogênicos , Concentração de Íons de Hidrogênio , Oceanos e MaresRESUMO
Local, regional and global targets have been set to halt marine biodiversity loss. Europe has set its own policy targets to achieve Good Environmental Status (GES) of marine ecosystems by implementing the Marine Strategy Framework Directive (MSFD) across member states. We combined an extensive dataset across five Mediterranean ecoregions including 26 Marine Protected Areas (MPAs), their reference unprotected areas, and a no-trawl case study. Our aim was to assess if MPAs reach GES, if their effects are local or can be detected at ecoregion level or up to a Mediterranean scale, and which are the ecosystem components driving GES achievement. This was undertaken by using the analytical tool NEAT (Nested Environmental status Assessment Tool), which allows an integrated assessment of the status of marine systems. We adopted an ecosystem approach by integrating data from several ecosystem components: the seagrass Posidonia oceanica, macroalgae, sea urchins and fish. Thresholds to define the GES were set by dedicated workshops and literature review. In the Western Mediterranean, most MPAs are in good/high status, with P. oceanica and fish driving this result within MPAs. However, GES is achieved only at a local level, and the Mediterranean Sea, as a whole, results in a moderate environmental status. Macroalgal forests are overall in bad condition, confirming their status at risk. The results are significantly affected by the assumption that discrete observations over small spatial scales are representative of the total extension investigated. This calls for large-scale, dedicated assessments to realistically detect environmental status changes under different conditions. Understanding MPAs effectiveness in reaching GES is crucial to assess their role as sentinel observatories of marine systems. MPAs and trawling bans can locally contribute to the attainment of GES and to the fulfillment of the MSFD objectives. Building confidence in setting thresholds between GES and non-GES, investing in long-term monitoring, increasing the spatial extent of sampling areas, rethinking and broadening the scope of complementary tools of protection (e.g., Natura 2000 Sites), are indicated as solutions to ameliorate the status of the basin.
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Biodiversidade , Ecossistema , Animais , Conservação dos Recursos Naturais , Europa (Continente) , Peixes , Mar MediterrâneoRESUMO
Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolation and reduced anthropogenic disturbance may increase ecological specialization in remote communities, and hence their vulnerability to secondary effects of diversity loss propagating through networks of interacting species. We show this to be true for reef fish communities across the globe. An increase in fish-coral dependency with the distance of coral reefs from human settlements, paired with the far-reaching impacts of global hazards, increases the risk of fish species loss, counteracting the benefits of remoteness. Hotspots of fish risk from fish-coral dependency are distinct from those caused by direct human impacts, increasing the number of risk hotspots by ~30% globally. These findings might apply to other ecosystems on Earth and depict a world where no place, no matter how remote, is safe for biodiversity, calling for a reconsideration of global conservation priorities.
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Antozoários/fisiologia , Branqueamento de Corais/efeitos adversos , Recifes de Corais , Peixes/fisiologia , Animais , Efeitos Antropogênicos , Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais , Humanos , Análise EspacialRESUMO
Global change is striking harder and faster in the Mediterranean Sea than elsewhere, where high levels of human pressure and proneness to climate change interact in modifying the structure and disrupting regulative mechanisms of marine ecosystems. Rocky reefs are particularly exposed to such environmental changes with ongoing trends of degradation being impressive. Due to the variety of habitat types and associated marine biodiversity, rocky reefs are critical for the functioning of marine ecosystems, and their decline could profoundly affect the provision of essential goods and services which human populations in coastal areas rely upon. Here, we provide an up-to-date overview of the status of rocky reefs, trends in human-driven changes undermining their integrity, and current and upcoming management and conservation strategies, attempting a projection on what could be the future of this essential component of Mediterranean marine ecosystems.
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Biodiversidade , Ecossistema , Mudança Climática , Conservação dos Recursos Naturais , Recifes de Corais , Humanos , Mar MediterrâneoRESUMO
Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in dissolved oxygen dynamics and hypoxia exposures can drive differences in vulnerabilities of coastal ecosystems and resources, but documentation of variability at regional scales is rare in open-coast systems. Using a regional collaborative network of dissolved oxygen and temperature sensors maintained by scientists and fishing cooperatives from California, USA, and Baja California, Mexico, we characterize spatial and temporal variability in dissolved oxygen and seawater temperature dynamics in kelp forest ecosystems across 13° of latitude in the productive California Current upwelling system. We find distinct latitudinal patterns of hypoxia exposure and evidence for upwelling and respiration as regional drivers of oxygen dynamics, as well as more localized effects. This regional and small-scale spatial variability in dissolved oxygen dynamics supports the use of adaptive management at local scales, and highlights the value of collaborative, large-scale coastal monitoring networks for informing effective adaptation strategies for coastal communities and fisheries in a changing climate.