7 results on '"Dehnert I."'
Search Results
2. Coral Reef Restoration in the Maldives: an assessment of techniques and challenges
- Author
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DEHNERT, INGA, Dehnert, I, GALLI, PAOLO, and PADOA SCHIOPPA, EMILIO
- Subjects
vivaio sospeso ,scogliera corallina ,trapianto ,restauro ecologico ,coral reef ,BIO/07 - ECOLOGIA ,coral gardening ,coral nursery ,transplantation - Abstract
Le scogliere coralline, conosciute per essere uno degli ecosistemi più ricchi di biodiversità del pianeta, stanno diminuendo ad un ritmo allarmante. Per contrastare le minacce poste dai cambiamenti climatici e da altri impatti di origine antropica gli sforzi di conservazione attiva, come il ripristino della scogliera corallina, sono aumentati a livello globale. Il ripristino ecologico si pone come obiettivo principale quello di assistere il recupero naturale, aumentandone la resilienza, delle scogliere coralline nel tentativo di preservare le numerose funzioni e servizi ecosistemici che questi habitat iconici forniscono alla società. La vulnerabilità delle Maldive alle minacce globali e locali è più evidente in quanto rappresentata da isole coralline con un'economia basata sulle attività come la pesca e il turismo. Tuttavia, sono disponibili poche informazioni sulle tecniche migliori di ripristino dei coralli che potrebbero essere applicate a livello regionale alle Maldive. Il "Coral Gardening", una tecnica che comprende l'allevamento di frammenti di coralli in vivai sommersi seguito dal trapianto di quest’ultimi in un sito di restauro, sembra particolarmente adatta per una località remota come l’arcipelago maldiviano. Il metodo, infatti, può essere utilizzato dalle comunità locali o organizzazioni turistiche per accelerare il recupero locale della scogliera corallina, creando al contempo consapevolezza e permettendo una gestione mirata delle sue risorse. Questo studio valuta l'applicazione su larga scala del "Coral Gardening" per il ripristino dei coralli alle Maldive, fornendo per la prima volta la necessaria validazione a livello regionale di questa tecnica. Per stimare le prestazioni di questo approccio di ripristino in diverse regioni e habitat (ad es. laguna e scogliera corallina), sono stati valutati un totale di sei vivai sommersi di corallo presenti sia sull'isola locale di Magoodhoo nell'atollo di Faafu che sull'isola turistica di Athuruga nell'atollo di Alif Dhaal. Il prestazioni della tecnica del coral gardening è stato valutato per tre diversi generi di coralli, quali Acropora, Pocillopora e Porites, utilizzando un protocollo di monitoraggio standard. Tale analisi hanno fornito parametri di riferimento regionali per la crescita dei frammenti in funzione del tempo e della profondità, nonché in funzione dei tassi di sopravvivenza dei coralli, che in genere superavano abbondantemente il 90% in entrambi gli habitat utilizzati. Inoltre, sono state prese in considerazione le interazioni ecologiche quali la fauna associata ai coralli e la presenza di predatori nel confronto tra i coralli allevati e trapiantati. L’utilizzo e l’efficacia delle tecniche di ripristino dei coralli sono state ulteriormente riesaminate rispetto al recupero naturale della scogliera corallina nel sito di ripopolamento, nonché delle potenziali implicazioni ecologiche delle attività di ripristino eseguite. In questo caso, il trapianto di coralli ha fornito ottimi risultati e ha apportato benefici significativi all'ambiente degradato della scogliera corallina, attraverso l’aumento in termini di abbondanza e diversità della comunità ittica, così come della copertura naturale dei coralli. Sebbene i risultati complessivi dello studio siano incoraggianti, questa ricerca affronta anche potenziali rischi per il successo del ripristino delle scogliere coralline. In particolare sono stati valutati i rischi inerenti gli effetti negativi legati ad un’interruzione prolungata delle attività di monitoraggio e manutenzione e degli eventuali impatti di patologie in grado di colpire i coralli. Nel complesso, i risultati presentati e le implicazioni pratiche ottenute grazie a questo lavoro forniranno una base scientifica per i futuri studi riguardanti il restauro delle scogliere coralline con la speranza che possano rappresentare una guida verso una conservazione di questo habitat più efficiente. Coral reefs, which are among the most biodiverse ecosystems on the planet, are declining at an alarming rate. To counteract the threats posed by climate change and other anthropogenic impacts, conservation efforts such as active coral reef restoration have increased globally. Ecological restoration aims to assist natural recovery and increase coral reefs resilience in an effort to preserve the many functions and services these iconic ecosystems provide to society. Under current climate scenarios, coastal and island populations are the first to suffer from continued ecosystem degradation. For example, the Maldives’ vulnerability to global and local coral reef threats is evident for a nation that lives on shallow reef islands with an economy driven by fisheries and tourism. However, little information is available on suitable, regionally tested coral restoration techniques that could be applied at an ecological meaningful scale in the Maldives. ‘Coral gardening’, which comprises fragment farming in coral nurseries followed by the transplantation of these corals to a restoration site, appears particularly suitable for remote locations like the Maldives. The method can be applied by local communities or tourism stakeholders to assist local reef recovery, while creating awareness, stewardship and even income opportunities. This research assesses the application of ‘coral gardening’ for upscaled coral restoration efforts in the Maldives, providing the necessary regional validation and useful insights into the various aspects of this technique for the first time. To evaluate the suitability and performance of this restoration approach across different regions and farming habitats (i.e., lagoon and reef), a total of six mid-water coral rope nurseries were assessed on the local island of Magoodhoo in Faafu Atoll and on Athuruga resort island in Alif Dhaal Atoll. Coral gardening success was examined for three different coral genera, namely Acropora, Pocillopora and Porites, using a common monitoring protocol. This delivered regional benchmarks for fragment growth over time and at different depths as well as coral survival, which typically exceeded 90% in both farming habitats. In addition, ecological interactions were investigated by including mutualistic fauna and predator associations in the assessments of farmed and transplanted corals. For example, a positive correlation between Trapezia guard crabs and farming stock health was observed, while the corallivorous nudibranch Phestilla is newly reported on coral nursery stock. Coral restoration demand and success is further reviewed in the context of natural reef recovery on the restoration site as well as potential ecological implications of restoration activities. Here, coral outplanting was successful and significantly benefitted the degraded reef environment, increasing fish abundance and diversity along with natural coral cover While the overall study results are encouraging, this research also addresses potential risks to coral restoration success, in particular the negative effects of prolonged monitoring and maintenance disruptions and the impacts of coral disease occurrence. Using a number of real case studies, it is demonstrated how these factors can diminish coral gardening outcomes and project success, if not managed in time. Overall, the findings presented and the practical applications concluded from this work hope to provide a scientific baseline for future restoration efforts that can guides restoration practitioners towards efficient conservation work.
- Published
- 2022
3. Assessing population collapse of Drupella spp. (Mollusca: Gastropoda) 2 years after a coral bleaching event in the Republic of Maldives
- Author
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Luca Saponari, Inga Dehnert, Paolo Galli, Simone Montano, Saponari, L, Dehnert, I, Galli, P, and Montano, S
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0106 biological sciences ,Coral bleaching ,Coral ,Population ,Predation ,Acropora ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Coral recovery ,Gastropoda ,Drupella ,Pocillopora ,education ,Reef ,education.field_of_study ,geography ,geography.geographical_feature_category ,biology ,Ecology ,010604 marine biology & hydrobiology ,Coral reef ,biology.organism_classification ,Corallivory - Abstract
Corallivory causes considerable damage to coral reefs and can exacerbate other disturbances. Among coral predators, Drupella spp. are considered as delayer of coral recovery in the Republic of Maldives, although little information is available on their ecology. Thus, we aimed to assess their population structure, feeding behaviour and spatial distribution around 2 years after a coral bleaching event in 2016. Biological and environmental data were collected using belt and line intercept transects in six shallow reefs in Maldives. The snails occurred in aggregations with a maximum of 62 individuals and exhibited a preference for branching corals. Yet, the gastropods showed a high plasticity in adapting feeding preferences to prey availability. Drupella spp. were homogenously distributed in the study area with an average of 9.04 ± 19.72 ind/200 m2. However, their occurrence was significantly different at the reef scale with the highest densities found in locations with higher coral cover. The impact of Drupella spp. appeared to be minimal with the population suffering from the loss of coral cover. We suggest that monitoring programs collect temporal- and spatial-scale data on non-outbreaking populations or non-aggregating populations to understand the dynamics of predation related to the co-occurrence of anthropogenic and natural impacts.
- Published
- 2021
4. Temporal patterns in coral disease prevalences at Thudufushi Island, Maldives, 2010-2022.
- Author
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Bises C, Gobbato J, Lainati N, Dehnert I, Siena F, Seveso D, Montalbetti E, Louis YD, and Montano S
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- Animals, Indian Ocean Islands epidemiology, Time Factors, Climate Change, Maldives, Anthozoa microbiology, Coral Reefs
- Abstract
Coral reefs are lately suffering a fast decline in biodiversity due to the coupled effect of climate change and disease outbreaks, which in recent decades have been reported with higher frequency and shorter intervals. Limited studies have been conducted on coral diseases in the Maldives resulting in the impossibility of assessing the temporal trend in their dynamics. In this context, we evaluated the change in the distribution, prevalence, and host range of 4 diseases, namely black band disease (BBD), brown band disease (BrB), skeletal eroding band (SEB) and white syndrome (WS), in the reef system around Thudufushi Island after an interval of 12 yr since the last assessment. In this period, the overall disease prevalence increased, except for BrB, with SEB showing the most severe increase in 2022 in comparison to 2010. The overall average prevalence of coral diseases is approximately 2%, indicating an increase of about 0.7% since 2010. Diseased coral colonies were found in all the investigated sites, with the east site being the most affected and SEB emerging as the most prevalent disease across all the investigated sites. The affected colonies belong to 13 genera, with Psammocora genus showing the highest overall mean disease prevalence. This study depicted a basic temporal trend in disease prevalence that confirms an increase in coral diseases in the region and calls for a dedicated national monitoring protocol to better understand and predict future coral disease dynamics at regional scales.
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- 2024
- Full Text
- View/download PDF
5. Effects of the COVID-19 lockdowns on the management of coral restoration projects.
- Author
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Montano S, Dehnert I, Seveso D, Maggioni D, Montalbetti E, Strona G, Siena F, Amir H, Antoine A, Marino-Ramirez C, Saponari L, Shah NJ, Azcarate Molina R, Alegria Ortega A, Galli P, and Montoya-Maya PH
- Abstract
Coral restoration initiatives are gaining significant momentum in a global effort to enhance the recovery of degraded coral reefs. However, the implementation and upkeep of coral nurseries are particularly demanding, so that unforeseen breaks in maintenance operations might jeopardize well-established projects. In the last 2 years, the COVID-19 pandemic has resulted in a temporary yet prolonged abandonment of several coral gardening infrastructures worldwide, including remote localities. Here we provide a first assessment of the potential impacts of monitoring and maintenance breakdown in a suite of coral restoration projects (based on floating rope nurseries) in Colombia, Seychelles, and Maldives. Our study comprises nine nurseries from six locations, hosting a total of 3,554 fragments belonging to three coral genera, that were left unsupervised for a period spanning from 29 to 61 weeks. Floating nursery structures experienced various levels of damage, and total fragment survival spanned from 40 to 95% among projects, with Pocillopora showing the highest survival rate in all locations present. Overall, our study shows that, under certain conditions, abandoned coral nurseries can remain functional for several months without suffering critical failure from biofouling and hydrodynamism. Still, even where gardening infrastructures were only marginally affected, the unavoidable interruptions in data collection have slowed down ongoing project progress, diminishing previous investments and reducing future funding opportunities. These results highlight the need to increase the resilience and self-sufficiency of coral restoration projects, so that the next global lockdown will not further shrink the increasing efforts to prevent coral reefs from disappearing., (© 2022 Society for Ecological Restoration.)
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- 2022
- Full Text
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6. Comparing different farming habitats for mid-water rope nurseries to advance coral restoration efforts in the Maldives.
- Author
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Dehnert I, Saponari L, Galli P, and Montano S
- Subjects
- Animals, Agriculture, Ecosystem, Maldives, Viverridae, Anthozoa
- Abstract
The need for comprehensive and effective coral restoration projects, as part of a broader conservation management strategy, is accelerating in the face of coral reef ecosystem decline. This study aims to expand the currently limited knowledge base for restoration techniques in the Maldives by testing the performance of mid-water rope nurseries in a lagoon and a reef habitat. We examined whether different coral farming habitats impacted fragment survival, health and growth of two coral genera and how the occurrence of mutualistic fauna, predation and disease influenced coral rearing success. Two nurseries were stocked with a total of 448 Pocillopora verrucosa and 96 Acropora spp. fragments, divided into different groups (four Pocillopora groups: lagoon nursery at 5 m; reef nursery at 5, 10 and 15 m; two Acropora groups: lagoon nursery at 5 m and reef nursery at 5 m). Eight fragment replicates from the same donor colony ( Pocillopora genets: N = 14, Acropora genets N = 6) were used in each group and monitored for one year. Our results show that fragment survival was high in both farming habitats (>90%), with P. verrucosa surviving significantly better in the lagoon and Acropora spp. surviving and growing significantly faster in the reef nursery. P. verrucosa growth rates were similar between reef and lagoon habitat. Different rearing depths in the reef nursery had no impact on the survival of P. verrucosa but coral growth decreased considerably with depth, reducing fragments' ecological volume augmentation and growth rates by almost half from 5 to 15 m depth. Further, higher fish predation rates on fragments were recorded on the reef, which did not impact overall nursery performance. Mutualistic fauna, which correlated positively with fragment survival, was more frequently observed in the lagoon nursery. The occurrence of disease was noted in both habitats, even though implications for fragment health were more severe in the lagoon. Overall, our study demonstrates that lagoon and reef nurseries are suitable for rearing large numbers of coral fragments for transplantation. Nevertheless, we recommend considering the specific environmental conditions of the farming habitat, in particular water quality and year-round accessibility, in each case and to adjust the coral farming strategy accordingly. We hope that this novel research encourages the increased application of mid-water rope nurseries for 'coral gardening' to advance coral reef recovery and climate resilience in the Maldives., Competing Interests: The authors declare there are no competing interests., (©2022 Dehnert et al.)
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- 2022
- Full Text
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7. Monitoring and assessing a 2-year outbreak of the corallivorous seastar Acanthaster planci in Ari Atoll, Republic of Maldives.
- Author
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Saponari L, Montalbetti E, Galli P, Strona G, Seveso D, Dehnert I, and Montano S
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- Animals, Coral Reefs, Feeding Behavior, Indian Ocean Islands, Population Dynamics, Anthozoa physiology, Food Chain, Life History Traits, Starfish physiology
- Abstract
Outbreaks of the corallivorous crown-of-thorns seastars have received increasing attention due to their negative impacts on coral reefs in the Indo-Pacific Ocean. However, outbreaks in remote and dislocated islands are still poorly understood. This study aims to begin filling informational gaps regarding outbreaks of Acanthaster planci in the remote islands of the central Ari Atoll, Republic of Maldives. The population of A. planci was monitored during three periods over 2 years (2015-2016) to evaluate variations in abundance and to characterise size structure and feeding behaviour. The outbreak appeared to be severe and active throughout the entire study period. The size structure analysis revealed a multimodal distribution dominated by individuals between 20 and 30 cm, suggesting that the outbreak may have resulted from a few nearby mass spawning events. Additionally, the most abundant live coral was Porites, which was also the most consumed genus; however, the electivity index showed a preference for corals of the genera Favites and Pavona. Finally, we also highlighted the need for more geographically extended surveys to better understand local patterns regarding outbreaks of A. planci in the Republic of Maldives.
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- 2018
- Full Text
- View/download PDF
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