1,721,067 research outputs found
Challenges in Restoring Mediterranean Seagrass Ecosystems in the Anthropocene
No full textThe intense human pressures in the Anthropocene epoch are causing an alarming decline in marine coastal ecosystems and an unprecedented loss of biodiversity. This situation underscores the urgency of making ecological restoration a global priority to recover degraded ecosystems. Meadows of the endemic Mediterranean seagrass Posidonia oceanica have lost more than half of their original extent in the last century, necessitating immediate conservation and management measures, supported by active restoration interventions. This paper explores new opportunities and provides specific recommendations to enhance restoration as a fundamental strategy for reversing the decline of P. oceanica ecosystems in the Mediterranean Sea. When a return to a historical pristine reference condition may not be feasible in the short term or desirable given current environmental conditions and uncertainty, transplanting the tolerant and fast-growing seagrass species Cymodocea nodosa could facilitate natural recolonization. This would occur through secondary ecological succession, benefiting the sensitive and slow-growing species P. oceanica. Future global and local efforts should primarily focus on proactive management to prevent further alterations by planning appropriate conservation measures in a timely manner to mitigate and reverse global changes. As a secondary step, restoration programs can be implemented with a focus on ‘target-oriented’ rather than ‘reference-oriented’ conditions, aiming to establish ecosystems capable of sustaining the future rather than replicating the historical environment
Editorial: Seascape Ecology: from characterization to evaluation of state and change over time
No full textA review of the classification systems for marine benthic habitats and the new updated Barcelona Convention classification for the Mediterranean
No full textThe Mediterranean Sea supports high levels of biodiversity and complexity but is facing increasing human pressures, so that strategies to protect and recover its ecosystems must be a priority in environmental policies. Benthic cartography represents the first step of marine spatial planning for the proper management and protection of our sea. Univocal habitat classification systems are thus needed to map, monitor, and inventory marine habitats, and to guarantee common and shared frames for a harmonized interpretation of the Mediterranean habitat types. In this paper we reviewed the existing classification systems of marine benthic habitats, to discuss the process of revision and updating of one of the first system developed under the Barcelona Convention (BC) in 1998 and adopted by all the Mediterranean countries. The BC classification was revised including the new habitats discovered in the last 30 years, and consistently with the criteria used to revise the EUropean Nature Information System (EUNIS), which is a comprehensive pan-European system for habitat identification. The updated BC classification is hierarchical with 5 levels, which allows representing the most suitable habitat level with respect to the restitution scale of the map. Each habitat is univocally identified by an alpha-numeric code, name and general description following the bionomic approach traditionally adopted in the Mediterranean benthic cartography since the late nineteen century. The new BC classification lists 128 main habitats up to the level 4, which may also contain sub-habitats at the level 5, i.e. associations and facies, totalising 394 habitat types (54% of new habitats with respect to the first BC classification). The updated BC classification system has been used for the selection of reference marine habitats that support two fundamental processes of environmental management: i) identification of Specially Marine Protected Areas according to the SPA/BD Protocol of Barcelona Convention; ii) selection of habitats to be monitored, as requested by the Integrated Monitoring and Assessment Programme and the European Directives (e.g., Water Framework and Marine Strategy). The new list of reference habitats, selected because of their high ecological and conservation value, contains 267 habitats, corresponding to 68% of the total habitats listed in the updated BC classification
Scientists’ warning on sustainability: the ecologist point of view, with examples from marine ecosystems
No full textIn recent years, the urgency of achieving sustainability has become a central focus across various scientific disciplines due to the escalating impacts of human activities on the environment in the Anthropocene. In this contribution to the scientists' warning series, we review key ecological insights essential for shaping sustainability strategies to mitigate environmental degradation, and we issue a warning on how sustainability should be pursued in response to these challenges. Drawing on the expertise of ecologists, who understand the complex interactions that underpin natural systems, we explore the balance between ecological, economic, and social dimensions of sustainability, providing examples of case studies on marine ecosystems. Fundamental ecological principles-such as biodiversity conservation, ecosystem services, resilience, and disturbance-are examined to highlight their role as the foundations of sustainable development. This review also underscores the importance of interdisciplinary collaboration in advancing sustainability practices that are both ecologically sound and socially viable. By identifying gaps in current knowledge and advocating for a paradigm shift toward prioritizing ecological integrity, we emphasize the urgent need for science-based policies to address today's environmental issues. Ultimately, this work frames the human-nature relationship as central to sustainable development, calling for enhanced ecological awareness to combat global change, decelerate biodiversity loss, and promote environmental protection
A Rapid Method to Identify the Effects of Coastal Artificialization on Posidonia oceanica Meadows in Coves
No full textThis study proposes a rapid and cost-effective method to identify the effects of coastal artificialization on the distribution of shallow Posidonia oceanica meadows. Seven embayed coves were selected along the Ligurian coastline (Italy, NW Mediterranean) to evaluate the influence of the coast geometry on the depth and morphology of the meadow upper limits (i.e., the shallowest depth reached by the plants towards the coastline). The areas under investigation are characterized by rocky coasts and exhibit varying degrees of embayment, resulting in different levels of exposure to wave action. The geometric features of embayed coastlines, along with hydrodynamics and physical parameters, were examined in relation to the structure of P. oceanica meadows within each cove. The results indicated that both natural and anthropogenic (i.e., artificial) coastal geometries influence the spatial distribution of P. oceanica meadows, leading to significant heterogeneity in their upper limits. The configuration of the embayment system produces various types of hydrodynamic circulation. The existence of a cellular circulation pattern leads to the formation of rip or megarip currents, which cause erosion in the shallow portions of the meadows and create sandy channels that disrupt the continuity of the meadows. Establishing a relationship between the hydrodynamics within the coves and the characteristics of the upper limits of the meadows proved to be a valuable method for promptly distinguishing whether the observed conditions stemmed from natural or human influences. This proposed approach enables a preliminary and cost-effective assessment of the origins of erosive processes affecting the shallow portions of P. oceanica meadows. Such an approach represents a clear management advantage in the environmental impact assessment of coastal engineering projects
Influence of Local Pressures on Maldivian Coral Reef Resilience Following Repeated Bleaching Events, and Recovery Perspectives
No full textTwo severe heat waves triggered coral bleaching and mass mortality in the Maldives in 1998 and 2016. Analysis of live coral cover data from 1997 to 2019 in shallow (5 m depth) reefs of the Maldives showed that the 1998 heat wave caused more than 90% of coral mortality leaving only 6.8 ± 0.3% of survived corals in all the shallow reefs investigated. No significant difference in coral mortality was observed among atolls with different levels of human pressure. Maldivian reefs needed 16 years to recover to the pre-bleaching hard coral cover values. The 2016 heat wave affected all reefs investigated, but reefs in atolls with higher human pressure showed greater coral mortality than reefs in atolls with lower human pressure. Additionally, exposed (ocean) reefs showed lower coral mortality than those in sheltered (lagoon) reefs. The reduced coral mortality in 2016 as compared to 1998 may provide some support to the Adaptive Bleaching Hypothesis (ABH) in shallow Maldivian reefs, but intensity and duration of the two heat waves were different. Analysis of coral cover data collected along depth profiles on the ocean sides of atolls, from 10 to 50 m, allowed the comparison of coral mortality at different depths to discuss the Deep Refuge Hypothesis (DRH). In the upper mesophotic zone (i.e., between 30 and 50 m), coral mortality after bleaching was negligible. However, live coral cover did not exceed 15%, a value lower than coral survival in shallow reefs. Low cover values of corals surviving in the mesophotic reefs suggest that their role as refuge or seed banks for the future recovery of some species in shallow-water reefs of the Maldives may be small. The repeatedly high coral mortality after bleaching events and the long recovery period, especially in sites with human pressure, suggest that the foreseen increased frequency of bleaching events would jeopardize the future of Maldivian reefs, and ask for reducing local pressures to improve their resilience
Idiosyncratic Recovery Patterns in Coral Reefs of the Maldives Following Climate Disturbance
No full textThe severe heatwave that occurred in April-May 2016 caused widespread bleaching and mortality in the Maldivian coral reefs. In this study, the main factors that influenced coral recovery were investigated, that is, reef typology and exposure (ocean vs. lagoon) and depth (5 m vs. 10 m). Field surveys were conducted in 2019 and 2021 on 26 Maldivian reefs through photographic samplings. Changes in coral community structure and composition were analysed using the percent cover of the dominant coral families in the Maldives (Acroporidae, Pocilloporidae, and Poritidae) and of a number of benthic categories (encrusting corals, soft-bodied organisms, abiotic components). Following the climate disturbance, most of the reefs were still dominated by abiotic components (mainly coral rubble and dead corals) after 5 years, although a slight recovery in hard coral cover was registered. Ocean reefs, dominated by massive Poritidae corals, exhibited a higher recovery capacity than lagoon reefs. Lagoon reefs displayed a higher coral mortality and spatial variability in their recovery patterns and in the coral community composition. Encrusting corals and soft-bodied organisms played a major role in the reef regeneration. The predicted increase in heatwaves frequency due to climate change makes long-term monitoring mandatory to tackle coral reefs' recovery potential and to evaluate their resilience to global warming. Photographic sampling represents a cost-effective methodology to monitor coral communities regularly and objectively evaluate changes in the abundance of the main reef components
Synergic effect of global thermal anomalies and local dredging activities on coral reefs of the Maldives
No full textWe investigated possible synergic effects on coral reefs of the local land reclamation activities in the Himmafushi Island (North Malè atoll, Maldives) and the global bleaching event that affected the Maldives in 2016. A BACI (Before-After Control-Impact) sampling design was adopted to contrast effects of dredging activities before and after the occurrence of both dredging and bleaching. The Reef Check protocol, a standardised and worldwide survey method, was applied to collect data through underwater visual surveys on corals, macro-zoobenthos, and fish communities. The bleaching in 2016 hit all the reefs investigated, but only in the reefs around Himmafushi (i.e., the impact sites) the live hard coral reduced significantly its cover and the sand deposited on reefs showed a fourfold increase. Substrate indicators (i.e., coral community and abiotic components) turned out to be more effective than macro-zoobenthos and fish in this short-term environmental impact study
Deep coralligenous outcrops of the Apulian continental shelf: Biodiversity and spatial variability of sediment-regulated assemblages
No full textStructure and spatial variability of coralligenous assemblages of the Apulian continental shelf in the southern Adriatic Sea were investigated. The area consists of small coralligenous outcrops distributed between 30 and 100 m of depth on coarse detritic or muddy bottom. Photographic samples, obtained through a Remotely Operated Vehicle, were analyzed to evaluate the abundance of the main taxa or morphological groups of macroalgae and sessile invertebrates, and the deposited sediment. A multifactorial sampling design was used to compare assemblages at two depth ranges, the shallow outcrops (between 35 and 45 m) and the deep outcrops (between 60 and 70 m), and to determine the main scales of spatial variation. Assemblages were dominated by encrusting and erect sponges, encrusting and filamentous algae, scleractinians, encrusting and erect bryozoans and the Zoantharia Parazoanthus axinellae. Deep assemblages were characterized by lower alpha and beta diversity, and by the decrease or disappearance of sensitive organisms, such as coralline macroalgae, scleractinians and erect bryozoans, and by the dominance of encrusting sponges, P. axinellae and hydrozoans. Sedimentation was higher on deep outcrops and was suggested to be the main driver of differences between shallow and deep assemblages. The peculiar composition of assemblages found in the Apulian continental shelf provides evidence that these outcrops represent an uncommon coralligenous habitat
The Millepora Zone Is Back: Recent Findings from the Northernmost Region of the Maldives
No full textThree species of the tropical hydrocoral genus Millepora were common and abundant in the Maldives before 1998, characterizing extensive shallow reef areas known as ‘Millepora zones’. The 1998 heat wave resulted in mass mortality of all the Millepora species, the characteristic Millepora zones disappeared, and only a few observations of isolated colonies were reported in the years ahead. A recent expedition (January 2024) to the northernmost region of the Maldives (Ihavandhippolhu Atoll) revealed new Millepora zones at 7–13 m depth, suggesting a potential repopulation of a vulnerable genus considered regionally extinct
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