Marine animal forests (MAFs) are living three-dimensional structure composed by ecosystem engineering species, structuring organisms that create and maintain high biodiversity and ecosystemic services of these habitats. Due to past and recent threats, both natural and human, these communities are rapidly shifting from highly resilient complex structures to more simplified ones. When the resilience of natural ecosystems is compromised, restoration actions may be necessary to recover damaged populations and communities. This study analyzes the growth and survival rate related to the transplantation of three corals species present in the Mediterranean: Paramuricea clavata, Corallium rubrum and Cladocora caespitosa. The parameters were investigated in the laboratory for C. caespitosa, and through field activities for the other two species, with transplantation from a donor site (Monte Argentario) to a recipient site (Isola Gallinara). In laboratory, 40 fragments of C. caespitosa were divided into light (12h light and 12h dark) and dark treatment (no light). Therefore, fragments were divided into 4 experimental tanks basing on the number of initial coralites (1, 2, 3 or 4) and studied for two months. Light treatment fragments did not bleach; on contrary, with the exception of a single fragment with 1 coralite, all the other fragments of the dark treatment bleached. Change in the total area of the coralites was found to be almost zero for all the fragments subjected to both treatments, with the exception of the fragments from the light treatment with 3 and 4 coralites, which showed statistically significant differences (repeated measures ANOVA, p<0.05). Production of new coralites occurred from 11 fragments of the light treatment and only from 2 fragments of the dark treatment. As anticipated, the other two species were transplanted into the sea, respectively at a depth of 35 m for C. rubrum and 40 m for P. clavata. Fragments of both species were attached to the rocky substrate through the use of a two-component resin, and, as regards the Red Coral, three transplantation techniques tested in the MERCES project were investigated. From the first transplantation activity, back in 2017, until now, a total of 87 fragments have been transplanted, of which 41 died or got lost and 46 survived. Considering the effectiveness of the grid (34 colonies out of 57 still in place), only the variation in number of apexes of the colonies transplanted with this technique were investigated. All the colonies showed an average monthly decrease, with a total overall of -0.106 ± 0.130 apexes/month. Considering all colonies from the first to the last monitoring activity, 15 colonies did not show neither a reduction neither an increment in the total number of apexes, 9 displayed a reduction, while only one colony showed 1 new apex. Of the 25 colonies of P. clavata transplanted, all the 16 remaining alive appeared healthy during monitoring activities, while the remaining 7 have been lost. 7 out of 16 colonies showed an increase in both height and width, 5 colonies showed a reduction in both parameters, while 4 colonies showed an increase in height and a decrease in width. Additionally, 6 colonies displayed 1 or 2 new branches, while conversely, 3 colonies suffered the loss of branches. Two colonies showed grow of the branches, while 4 colonies showed a branch size reduction. Nonetheless, five colonies did not show any structural change, while 1 of the 2 colonies that initially displayed a tissue damage showed full recovery. Future research should improve the validity of this study enhancing restoration effectiveness both on field and in laboratory.
Le foreste animali marine sono complesse strutture viventi composte da specie strutturanti che garantiscono, con la loro tridimensionalità, la formazione e il mantenimento di un'elevata biodiversità e di svariati servizi ecosistemici. A causa delle minacce passate e recenti, sia di origine naturale che umana, queste comunità si stanno rapidamente impoverendo, passando da strutture complesse altamente resilienti a strutture più semplificate. Quando la resilienza degli ecosistemi naturali è compromessa, le azioni di restauro potrebbero essere significative per il recupero delle popolazioni e delle comunità danneggiate. Questo studio analizza il tasso di crescita e sopravvivenza legato al trapianto di tre specie di coralli presenti nel Mediterraneo: Paramuricea clavata, Corallium rubrum e Cladocora caespitosa. I parametri sono stati studiati in laboratorio per C. caespitosa, e mediante attività di campo per le altre due specie, con trapianto da un sito donatore (Monte Argentario, Mar Tirreno settentrionale) a uno ricevente (Isola Gallinara, Mar Ligure). In laboratorio, 40 frammenti di C. caespitosa sono stati divisi in trattamento luce (12h:12h luce:buio) e trattamento buio (24h buio). I frammenti sono stati divisi in 4 vasche sperimentali in base al numero di coralliti iniziali (1, 2, 3 o 4) e studiati per due mesi. Tutti i frammenti in condizioni di oscurità sono sbiancati, al contrario, di quelli mantenuti con il trattamento con la luce. La variazione dell’area dei frammenti è risultata quasi nulla per entrambi i trattamenti, ad eccezione dei frammenti con 3 e 4 coralliti esposti alla luce, che hanno mostrato differenze significative, grazie alla produzione di nuovi coralliti durante i due mesi di esperimento. Le altre due specie sono state trapiantate a una profondità di 35 e 40 m rispettivamente per C. rubrum e P. clavata. Frammenti di entrambe le specie sono stati attaccati al substrato roccioso utilizzando una resina bicomponente, e per il corallo rosso sono state studiate tre tecniche di trapianto (ovvero resina epossidica, griglia e polistirolo) testate nel progetto MERCES. Dalla prima attività di trapianto, avvenuta nel 2017, sono stati trapiantati complessivamente 87 frammenti, di cui 46 sopravvissuti. Considerando l'efficacia della griglia (34 colonie su 57 ancora in sede), è stata indagata la variazione nel numero di apici delle sole colonie trapiantate con questa tecnica. Tutte le colonie hanno mostrato una diminuzione media mensile di -0,106 ± 0,130 apici/mese, con un solo trapianto che ha mostrato 1 nuovo apice. Delle 25 colonie di P. clavata trapiantate, 16 sono ancora in sede dopo 2 mesi e appaiono sane. La maggior parte delle colonie ha mostrato un aumento almeno in altezza, con la produzione di nuovi rami, mentre altre hanno subito la perdita di numerosi rami. Inoltre, una delle colonie che mostrava inizialmente danni tissutali, ha mostrato, dopo 2 mesi, un pieno recupero. Un monitoraggio a lungo termine aiuterà a comprendere meglio il tasso di crescita delle popolazioni trapiantate e a confermare l’efficacia dei trapianti e la sua possibile applicazione su scala più ampia.
Monitoraggio dei tassi di crescita e sopravvivenza di coralli usati in azioni di restauro: i casi di studio di Paramuricea clavata, Corallium rubrum e Cladocora caespitosa
ZILLE, ALEX
2022/2023
Abstract
Marine animal forests (MAFs) are living three-dimensional structure composed by ecosystem engineering species, structuring organisms that create and maintain high biodiversity and ecosystemic services of these habitats. Due to past and recent threats, both natural and human, these communities are rapidly shifting from highly resilient complex structures to more simplified ones. When the resilience of natural ecosystems is compromised, restoration actions may be necessary to recover damaged populations and communities. This study analyzes the growth and survival rate related to the transplantation of three corals species present in the Mediterranean: Paramuricea clavata, Corallium rubrum and Cladocora caespitosa. The parameters were investigated in the laboratory for C. caespitosa, and through field activities for the other two species, with transplantation from a donor site (Monte Argentario) to a recipient site (Isola Gallinara). In laboratory, 40 fragments of C. caespitosa were divided into light (12h light and 12h dark) and dark treatment (no light). Therefore, fragments were divided into 4 experimental tanks basing on the number of initial coralites (1, 2, 3 or 4) and studied for two months. Light treatment fragments did not bleach; on contrary, with the exception of a single fragment with 1 coralite, all the other fragments of the dark treatment bleached. Change in the total area of the coralites was found to be almost zero for all the fragments subjected to both treatments, with the exception of the fragments from the light treatment with 3 and 4 coralites, which showed statistically significant differences (repeated measures ANOVA, p<0.05). Production of new coralites occurred from 11 fragments of the light treatment and only from 2 fragments of the dark treatment. As anticipated, the other two species were transplanted into the sea, respectively at a depth of 35 m for C. rubrum and 40 m for P. clavata. Fragments of both species were attached to the rocky substrate through the use of a two-component resin, and, as regards the Red Coral, three transplantation techniques tested in the MERCES project were investigated. From the first transplantation activity, back in 2017, until now, a total of 87 fragments have been transplanted, of which 41 died or got lost and 46 survived. Considering the effectiveness of the grid (34 colonies out of 57 still in place), only the variation in number of apexes of the colonies transplanted with this technique were investigated. All the colonies showed an average monthly decrease, with a total overall of -0.106 ± 0.130 apexes/month. Considering all colonies from the first to the last monitoring activity, 15 colonies did not show neither a reduction neither an increment in the total number of apexes, 9 displayed a reduction, while only one colony showed 1 new apex. Of the 25 colonies of P. clavata transplanted, all the 16 remaining alive appeared healthy during monitoring activities, while the remaining 7 have been lost. 7 out of 16 colonies showed an increase in both height and width, 5 colonies showed a reduction in both parameters, while 4 colonies showed an increase in height and a decrease in width. Additionally, 6 colonies displayed 1 or 2 new branches, while conversely, 3 colonies suffered the loss of branches. Two colonies showed grow of the branches, while 4 colonies showed a branch size reduction. Nonetheless, five colonies did not show any structural change, while 1 of the 2 colonies that initially displayed a tissue damage showed full recovery. Future research should improve the validity of this study enhancing restoration effectiveness both on field and in laboratory.| File | Dimensione | Formato | |
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Descrizione: Tesi - Growth rate and survival of transplanted corals: Paramuricea clavata, Corallium rubrum and Cladocora caespitosa case studies - Alex Zille
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https://hdl.handle.net/20.500.12075/14857