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Map showing the location of the culture laboratory facilities and the donor (DS) and receiving (RS) sites. Full-size DOI: 10.7717/peerj.7290/fig-1
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In the Mediterranean Sea, brown algae belonging to the Cystoseira genus play a valuable role as foundation species. Due to evidences of regression/loss of the habitats of these species caused by the interplay of human and climatic disturbances, active restoration measures have been encouraged by EU regulations. In particular, nondestructive restora...
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... collected in June from a healthy population located in the Portofino MPA (donor site) along a 200-m stretch of coastline. After a laboratory culturing period, the juveniles were transplanted into the Cinque Terre MPA (receiving site; approximately 80 km from the donor site). Both MPAs are located in the Ligurian Sea, northwestern Mediterranean (Fig. 1). The sites are characterized by a tide in the range of 30 cm (under these conditions, barometric pressure effects may have a dominant effect on the water level) and an average spring temperature of 20 C. After sampling, the apices were gently cleaned with tweezers and rinsed with filtered seawater to remove adherent biofouling and ...
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... on the water level) and an average spring temperature of 20 C. After sampling, the apices were gently cleaned with tweezers and rinsed with filtered seawater to remove adherent biofouling and detritus. Then, the apices, which were wrapped in seawater-wetted towels, were delivered within 24 h to the laboratory in Trieste (northeastern Italy; Fig. 1) under dark, cold, and humid conditions for culturing in environmentally controlled ...
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... the next day (20th July 2018, Time 0), the tiles were carefully transported to the field, using a rubber boat. Eight patches (Fig. S1) were established in the previous weeks: 50 holes were drilled in each patch and screws placed within them in advance. On the day of implementation, the tiles were quickly screwed to the rocks. Overall, the deployment of 400 tiles was performed in approximately 5 h. On the days of transport and deployment, the air temperature was in the ...
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... collected in June from a healthy population located in the Portofino MPA (donor site) along a 200-m stretch of coastline. After a laboratory culturing period, the juveniles were transplanted into the Cinque Terre MPA (receiving site; approximately 80 km from the donor site). Both MPAs are located in the Ligurian Sea, northwestern Mediterranean (Fig. 1). The sites are characterized by a tide in the range of 30 cm (under these conditions, barometric pressure effects may have a dominant effect on the water level) and an average spring temperature of 20 C. After sampling, the apices were gently cleaned with tweezers and rinsed with filtered seawater to remove adherent biofouling and ...
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... on the water level) and an average spring temperature of 20 C. After sampling, the apices were gently cleaned with tweezers and rinsed with filtered seawater to remove adherent biofouling and detritus. Then, the apices, which were wrapped in seawater-wetted towels, were delivered within 24 h to the laboratory in Trieste (northeastern Italy; Fig. 1) under dark, cold, and humid conditions for culturing in environmentally controlled ...
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... the next day (20th July 2018, Time 0), the tiles were carefully transported to the field, using a rubber boat. Eight patches (Fig. S1) were established in the previous weeks: 50 holes were drilled in each patch and screws placed within them in advance. On the day of implementation, the tiles were quickly screwed to the rocks. Overall, the deployment of 400 tiles was performed in approximately 5 h. On the days of transport and deployment, the air temperature was in the ...
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... collected in June from a healthy population located in the Portofino MPA (donor site) along a 200-m stretch of coastline. After a laboratory culturing period, the juveniles were transplanted into the Cinque Terre MPA (receiving site; approximately 80 km from the donor site). Both MPAs are located in the Ligurian Sea, northwestern Mediterranean (Fig. 1). The sites are characterized by a tide in the range of 30 cm (under these conditions, barometric pressure effects may have a dominant effect on the water level) and an average spring temperature of 20 C. After sampling, the apices were gently cleaned with tweezers and rinsed with filtered seawater to remove adherent biofouling and ...
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... on the water level) and an average spring temperature of 20 C. After sampling, the apices were gently cleaned with tweezers and rinsed with filtered seawater to remove adherent biofouling and detritus. Then, the apices, which were wrapped in seawater-wetted towels, were delivered within 24 h to the laboratory in Trieste (northeastern Italy; Fig. 1) under dark, cold, and humid conditions for culturing in environmentally controlled ...
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... the next day (20th July 2018, Time 0), the tiles were carefully transported to the field, using a rubber boat. Eight patches (Fig. S1) were established in the previous weeks: 50 holes were drilled in each patch and screws placed within them in advance. On the day of implementation, the tiles were quickly screwed to the rocks. Overall, the deployment of 400 tiles was performed in approximately 5 h. On the days of transport and deployment, the air temperature was in the ...
Citations
... These include 1) direct transplantation of adult thalli from donor populations into artificial or natural structures to allow recruitment at the transplanted site (Falace et al. 2006;Susini et al. 2007), 2) harvesting fertile branches and securing them near the seabed to release recruits in-situ (Verdura et al. 2018), and 3) culturing the recruits ex-situ under controlled conditions (Falace et al. 2018) before outplanting them at the restoration sites once they have reached a certain size or stage (Savonitto et al. 2021). The latter has proven effective in yielding a significant number of healthy and relatively large recruits for reintroduction into the environment, with minimal impact on existing donor populations (Clausing et al. 2023;De La Fuente et al. 2019;Falace et al. 2018;Orlando-Bonaca et al. 2022;Savonitto et al. 2019). While several initiatives in the Mediterranean have aimed to restore endemic species (e.g. ...
Brown algal forests provide many ecosystem services but are declining worldwide, prompting a growing number of conservation and restoration efforts. Recent attempts to recover Cystoseira forests are encouraging in the Mediterranean, but whether this is possible in more challenging Atlantic conditions has not yet been investigated. In this study, we assess the feasibility of cultivating Gongolaria nodicaulis by producing ex-situ recruits for reforestation on the Atlantic coast of Morocco. Embryos of G. nodicaulis were cultured on clay tiles for 26 days under controlled conditions without water motion, reaching an average length of 3 mm before being outplanted on the intertidal zone. The transplants were monitored for six months. Recruits experienced high loss rates, approximately 47 % of zygotes within 7 days in culture and 75 % of outplanted seedlings within 10 days in the field. The latter might result from natural self-thinning (competition), but our observations suggested that it was also largely due to the weak attachment of recruits to the tiles resulting from cultivation under calm conditions. Six months after the transplants, the surviving individuals reached the size of wild adult algae (average length of 13.5 cm), and some even became reproductive. Globally, survival rates, growth, physiological condition and fertility in this restoration pilot suggest that ex-situ recruitment and outplanting of G. nodicaulis is a promising approach to recover forests in Atlantic Morocco.
... Over the last decade, efforts have been implemented to restore degraded marine algal forests in the Mediterranean Sea, using both insitu (Verdura et al., 2018) and ex-situ (Falace et al., 2018) techniques. Some relevant achievements concern the establishment of culture protocols for some of the species (Falace et al., 2018) and the layout of the deployment at sea, also preventing grazing pressure (De La Fuente et al., 2019b;Clausing et al., 2023;Monserrat et al., 2023). Yet, there is still a very large stochasticity that jeopardizes restoration efforts. ...
... From a restoration perspective, extreme climatic events, such as the occurrence of storms, temperature increases and MHWs, can, for example, hamper the survival of outplanted seedlings (De La Fuente et al., 2019b) or affect the growth of embryos or alter the reproductive phenology of species (Falace et al., 2021;Bevilacqua et al., 2019;Savonitto et al., 2021). These effects on the survival of the early stages, which hinder the long-term development of species, also represent a bottleneck for restoration efficiency. ...
... In the summer of 2022, different ex-situ restoration activities were implemented for Ericaria amentacea, an intertidal species whose restoration is largely established (Falace et al., 2018;De La Fuente et al., 2019b;Clausing et al., 2023). Fertile apices were collected at three sites along a latitudinal gradient (Ligurian Sea: Bogliasco in Liguria; Tyrrhenian Sea: Capri in Campania; Ionian Sea: Brucoli in Sicily) in June/July, when the species is known to achieve sexual maturity. ...
... Ugarte and Sharp 2001, Bellgrove et al. 2017, Coleman and Wernberg 2017, De La Fuente et al. 2019, Vergés et al. 2020, Fragkopoulou et al. 2022. ...
1. Fucoid forests are areas dominated by marine brown seaweed in the taxonomic order Fucales that, like the better-known marine foundation species - corals, kelps, seagrasses, salt marshes, and mangroves - are threatened by anthropogenic stressors. 2. Fucoid forests are fabulous and important because they, like the better-known marine foundation species (i) span large areas, bioregions, and ecosystems, (ii) provide ecological functions such as high productivity and biodiversity, and (iii) support a variety of ecosystem services including habitat for commercial fishery species, food for humans and cultural values. 3. Fucoid forests are, based on a new citation analysis, forgotten worldwide, because they are described orders of magnitude less than the better-known marine foundation species, in ecology and marine biology textbooks, in Google Scholar and Scopus databases over scientific literature, and in recent reports and reviews about seaweed forests. 4. Fucoid forests would be less forgotten if more people acknowledge their biological importance and societal value more often and equate their importance to that of the better-known marine foundation species. Perhaps name-recognition would also improve if fucoids are unified under a non-taxonomic common name across teaching, research, management, and conservation, like the better-known marine foundation species. We agree with the marine scientists that have used ‘rockweed’ as such a common name to describe all fucoids, but other seaweed-experts disagree because they (a) do not agree fucoids are forgotten, (b) dislike common names or (c) argue rockweed should only describe fucoid species in the family Fucaceae.
... The ongoing reduction of Cystoseira s.l. stands across the basin, replaced by less complex algal turfs or barren grounds, has raised wide concerns about potential consequences for marine biodiversity and ecosystem functioning (Sales et al., 2011;Bianchelli and Danovaro, 2020;Peleg et al., 2020), fuelling intense efforts to restore lost populations (e.g., Verdura et al., 2018;De La Fuente et al., 2019;Clausing et al., 2023;Orlando-Bonaca et al., 2022). Despite the current emphasis on the potential depletion of ecosystem functions (e.g., carbon sequestration, nutrient cycling) associated with the decline of coastal marine forests (Krause-Jensen et al., 2018;Filbee-Dexter et al., 2022), information about traits of macroalgae (including all biological and ecological features of species affecting growth, reproduction and survival of individuals or that, at higher levels of biological organization, may reflect on community and ecosystem functioning; see Violle et al., 2007) is often scattered and inconsistent requiring renewed efforts for data collection and re-organization (Vranken et al., 2023). ...
... species. For example, restoration interventions on Cystoseira s. l. stands are often restricted to relatively small areas (Verdura et al., 2018;De La Fuente et al., 2019), which could match the scale at which key functional traits are more variable. Given that restoration costs for Cystoseira s.l. ...
Cystoseira sensu lato are fucoid algae that form dense stands on intertidal and subtidal rocky reefs sustaining species-rich associated assemblages. The increasing human pressure is causing the decline of these marine forests, raising wide concerns on the ecological consequences of their loss. Yet, little is known about functional trait variables of Cystoseira s.l. species, which are essential to a deeper understanding of their contribution to the functioning of coastal ecosystems. We analysed the intraspecific spatial variation of the total organic matter, Corg, N and P contents in Ericaria amentacea from intertidal rocky shores in the W Mediterranean Sea. Specifically, we quantified spatial patterns of variation of traits at large (100 s km), small (1000 s m), and local (100 s cm) scale. We also explored potential interspecific variation by comparing the combined functional profile of trait variables between E. amentacea and Cystoseira compressa, an often co-occurring or vicariant species. Tissue contents of organic matter, Corg, N and P, were consistent among E. amentacea stands, supporting the hypothesis of a large-scale (100 s km) spatial homogeneity of such key traits in this species. Overlapping functional profiles between E. amentacea and C. compressa also suggested putative interspecific trait congruencies. However, a small-scale (1000 s m) significant variability was found for all trait variables in E. amentacea. Variance components at small and local (100 s cm) scale accounted for the largest contribution to the total spatial variation for all traits, recommending caution in the use of small and local-scale trait values to generalize functional performances of Cystoseira s.l. forests over large areas. This study represents one of the first attempts to shed light on the variability of key functional attributes of Cystoseira s.l. species at a range of spatial scales, which could assist more reliable assessments of their functional features and improve their management and conservation.
... Current restoration approaches are based on enhancement of recruitment obtained by stimulating sexual reproduction and consequent production of numerous germlings (which are then expected to grow into adult specimens and gradually form self-maintaining populations). The germlings can be produced in controlled conditions in the laboratory (ex situ methods; Falace et al., 2018;Verdura et al., 2018;De La Fuente et al., 2019;Clausing et al., 2022;Lardi et al., 2022) or directly in the field (in situ methods; Verdura et al., 2018;Medrano et al., 2020a). In both cases, the availability of fertile branches containing large numbers of mature gametes is a key requirement. ...
Active marine restoration is strongly encouraged to prevent the loss of the valuable habitats formed by Cystoseira sensu lato species, since they enhance biodiversity and preserve ecosystem functions and services. Current restoration interventions are mainly based on recruitment enhancement methods by deploying bags with fertile receptacles in situ or by outplanting juveniles grown ex situ under laboratory conditions. These methods allow the recovery of endangered species avoiding the depletion of the donor populations. In all cases, a priori knowledge of the reproductive phenology and recruitment periods of the species to be restored is essential, since the success of restoration techniques relies on collecting fertile branches and the obtention and survival of recruits. For their collection, identified donor populations characterized by dense Cystoseira s.l. cover should be studied. Specifically, monitoring the reproductive phenology of populations is crucial to detect the period of the year in which they develop mature reproductive structures and to understand how it might be linked to environmental conditions. Then, these general patterns on the reproductive phenology of Cystoseira s.l. species are essential to determine the most suitable time and conditions to plan for the most effective restoration action. Here, we provide a cost-effective and friendly protocol that can be easily and widely implemented for all Cystoseira s.l. species. We pose that this protocol provides a standardized and useful methodology to understand the environmental factors driving the optimal periods for sampling fertile branches across the Mediterranean Sea, and thus it can be an essential tool to plan future restoration actions.
... Macroalgal restoration efforts targeting Cystoseira species in the Mediterranean Sea only started in 2006 (see Gianni et al., 2013 for a review). Since 2011, collaborative efforts generated knowledge on restoration techniques, protocols and trials ( Figures 1E, F), as well as complementary actions (Sales et al., 2015;Falace et al., 2018;Verdura et al., 2018;De La Fuente et al., 2019;Tamburello et al., 2019;Medrano et al., 2020;Orlando-Bonaca et al., 2022), roadmaps (Cebrian et al., 2021) and spatial prioritisation (Fabbrizzi et al., 2020;Fabbrizzi et al., 2023). Most of these efforts have been led and developed by academic researchers from public research institutions and universities, at small scales, reflecting the relatively incipient stage of macroalgal restoration (Eger et al., 2022a). ...
... Recruitment enhancement methods, which take advantage of the high reproductive potential of these species, have proven to be cost-feasible in the restoration of Cystoseira s.l. populations, while at the same time having limited effects on donor populations (e.g., Verdura et al., 2018;De La Fuente et al., 2019;Tamburello et al., 2019;Medrano et al., 2020). Recruit enhancement can be achieved through different techniques: obtaining new recruits directly at sea (in situ) or culturing new recruits in aquaria (ex situ) (Falace et al., 2018;Verdura et al., 2018). ...
... species, it is suggested that success should encompass the first reproductive cycle of the restored individuals, which constitutes the first step towards a self-sustainable population . Based on commonly used indicators (De La Fuente et al., 2019;Tamburello et al., 2019;Orlando-Bonaca et al., 2021a;Medrano et al., 2020;Savonitto et al., 2021;Orlando-Bonaca et al., 2022;Clausing et al., 2023) and knowledge gained by the longest successful restoration action in the Mediterranean (restoration of Gongolaria barbata in Cala Teulera, Menorca, Verdura et al., 2018;Gran et al., 2022), a list of indicators is proposed in Table 2. Different attributes to be monitored or sampling periods may be needed for different Cystoseira s.l. species (e.g., different monitoring for deep, or waveexposed species) and different sites (i.e., with shifted reproductive times at different localities), supported by both species-and sitespecific pilot studies. ...
Macroalgal forests characterised by species of the genus Cystoseira sensu lato form important shallow coastal rocky habitats in the Mediterranean Sea. These forests support a high biodiversity and provide important ecosystem services and societal benefits. Currently these habitats are often in a poor condition in many areas, due to loss and degradation from both anthropogenic and climate stressors. Restoration has recently moved to the forefront of the United Nations and European Union agendas to reverse this trend, particularly in the last decade with the implementation of various international policies. However, this has been in the form of generic targets (e.g., restoration of 30% of degraded habitats by 2030) and has not been linked to specifically what habitat or species to restore, where and how. Initial targets have been missed, new targets are expected through the proposed EU Nature Restoration Law, but overall guidance is still lacking. There are few specific guides to marine habitat restoration limited to mostly seagrass, corals and shellfish. As a priority action for the recovery of coastal marine ecosystems a decision-support framework has been developed for the restoration of Mediterranean macroalgal forests, comprising a stepwise decision tree with additional descriptions of key elements to be considered for a restoration action. The decision tree includes steps concerning current and historical forest presence, site local condition assessment and choice of actions. Key considerations include restoration implementation (competence, society and support, finance and governance), success evaluation (at the target species and the ecosystem level) and long-term management. The framework builds on existing work on Cystoseira s.l. restoration, the work carried out in the EU AFRIMED project, but also on principles and guidelines in place for both generic and specific marine habitats. The work reported here has involved the expertise of scientists and information from stakeholders. Gaps were identified and recommendations were made, dealing with stressors, coordinating and networking stakeholders, integrating top down policy and bottom up initiatives, funding of restoration actions, establishing synergies between restoration, conservation and marine spatial planning and finally communication and publicity.
... They are long-lived species [7,8] with relatively large size and high biomass [9]. Important ecosystem services [10] provided by Cystoseira algal forests include high primary production [11], rich communities of algae and invertebrates grown germlings [10,[46][47][48]64,[68][69][70][71][72]. Non-destructive in situ and ex situ techniques are best suited for the recovery of endangered species to avoid the depletion of donor populations [10]. ...
... They are long-lived species [7,8] with relatively large size and high biomass [9]. Important ecosystem services [10] provided by Cystoseira algal forests include high primary production [11], rich communities of algae and invertebrates grown germlings [10,[46][47][48]64,[68][69][70][71][72]. Non-destructive in situ and ex situ techniques are best suited for the recovery of endangered species to avoid the depletion of donor populations [10]. ...
... Important ecosystem services [10] provided by Cystoseira algal forests include high primary production [11], rich communities of algae and invertebrates grown germlings [10,[46][47][48]64,[68][69][70][71][72]. Non-destructive in situ and ex situ techniques are best suited for the recovery of endangered species to avoid the depletion of donor populations [10]. In particular, several efforts have been made to develop cost-and time-efficient methods for the ex situ cultivation of Cystoseira s.l. ...
Brown algae from genus Cystoseira s.l. form dense underwater forests that represent the most productive areas in the Mediterranean Sea. Due to the combined effects of global and local stressors such as climate change, urbanization, and herbivore outbreaks, there has been a severe decline in brown algal forests in the Mediterranean Sea. Natural recovery of depleted sites is unlikely due to the low dispersal capacity of these species, and efficient techniques to restore such habitats are needed. In this context, the aims of our study were (1) to improve and simplify the current ex situ laboratory protocol for the cultivation of Gongolaria barbata by testing the feasibility of some cost-effective and time-efficient techniques on two donor sites of G. barbata and (2) to evaluate the survival and growth of young thalli during the laboratory phase and during the most critical five months after out-planting. Specifically, the following ex situ cultivation methods were tested: (A) cultivation on clay tiles in mesocosms with culture water prepared by three different procedures (a) filtered seawater with a 0.22 μm filter membrane, (b) filtered seawater with a 0.7 μm filter membrane (GF), and (c) UV-sterilized water, and (B) cultivation on clay tiles in open laboratory systems. After two weeks, all thalli were fixed to plastic lantern net baskets suspended at a depth of 2 m in the coastal sea (hybrid method), and the algal success was monitored in relation to the different donor sites and cultivation protocol. The satisfactory results of this study indicate that UV-sterilized water is suitable for the cultivation of G. barbata in mesocosm, which significantly reduces the cost of the laboratory phase. This opens the possibility of numerous and frequent algal cultures during the reproductive period of the species. Additionally, if the young thalli remain in the lantern net baskets for an extended period of several months, they can grow significantly in the marine environment without being exposed to pressure from herbivorous fish.
... Considering the widespread deforestation of Mediterranean macroalgal forests (Cormaci and Furnari, 1999;Thibaut et al., 2015;Mariani et al., 2019) and the important ecosystem services they provide, important efforts have recently been made to promote their protection and restoration (Eger et al., 2021). Currently, restoration techniques based on recruitment enhancement (by obtaining new recruits from both ex-situ and in-situ techniques) are increasingly being used to restore marine forests (Falace et al., 2018;Verdura et al., 2018;De La Fuente et al., 2019;Cebrian et al., 2021;Savonitto et al., 2021). However, herbivory pressure still constitutes one of the major problems when planning marine forests restoration actions, since it is one of the main causes of failure (Gianni et al., 2013;Gianni et al., 2018;Tamburello et al., 2019b;Savonitto et al., 2021). ...
... To stimulate the release of gametes, the apical branches were maintained at 4°C in the dark overnight before placing them on the culture tanks. The day after, the apical fertile branches were placed on the surface of three 30-l closed system tanks (60 g FW of apical fertile branches per tank) to obtain recruits on the clean natural rock substrates previously placed on the bottom of the tanks (Verdura et al., 2018;De La Fuente et al., 2019). The apical fertile branches were kept for 4 days on the surface of the tanks to release the zygotes. ...
... Replicating natural conditions in experimental tanks is difficult, and recruits in the laboratory grew less than the ones in Sainte Marguerite (obtained from the in-situ technique). For restoration actions it is counselled to transplant the recruits after a few weeks (Falace et al., 2018;De La Fuente et al., 2019;Savonitto et al., 2021). The recruits of the two field experiments were obtained using different techniques that were chosen in function of the characteristic of each site (e.g., forested/no forested, past presence of a forest, potential herbivory pressure; Cebrian et al., 2021). ...
Grazing is one of the most important biological factors controlling the abundance of early-life stages of fucoids and one of the major issues when restoring marine forests. Benthic macroinvertebrates (e.g., sea urchins) and fish shape and regulate benthic macroalgal communities from polar to tropical regions and can be responsible for regime shifts leading to the predominance of turfs and/or barren grounds. However, other herbivores (i.e., mesograzers) could also significantly participate in the grazing, especially on early-life stages, hampering the persistence and capacity of Cystoseira sensu lato populations to recover after major disturbances and being a cause of failure of restoration actions. We performed experiments in the field and in mesocosm in order to investigate the herbivory pressure and the effects of different grazers on recruits of Cystoseira compressa. The results highlight that non-strict herbivorous invertebrates, such as Clibanarius erythropus, Cerithium vulgatum, and Idotea balthica, graze on recruits of Cystoseira s.l. spp., with I. balthica showing the highest consumption rate. We concluded that biotic factors such as herbivory, which affect key life stages, can be crucial for the conservation of Cystoseira s.l. forests and need to be better understood and considered on a case-by-case basis when planning restoration actions.
... However, as a result of multiple anthropogenic stressors (e.g., coastal urbanization, eutrophication, sediment input and overgrazing), these species and their habitats have been steadily declining in many coastal regions and are now critically endangered (Mangialajo et al. 2008;Falace et al. 2010;Vergés et al. 2014;Thibaut et al. 2015;Blanfuné et al. 2016;Valdazo et al. 2017;Mancuso et al. 2018). This trend of degradation is fueling intensive research efforts aimed at implementing effective measures to replenish declining populations of Cystoseira s.l. or restore lost forests (Falace et al. 2018;Verdura et al. 2018;De La Fuente et al. 2019;Orlando-Bonaca et al. 2021a, 2022Savonitto et al. 2021). ...
... Recruitment-enhancement, both ex situ and in situ, are both more sustainable methods than transplanting adult thalli (Falace et al. 2006) in order to restore macroalgal forests as they rely on harvesting only reproductive, fertile thallus branches which avoids the complete removal of adult plants from wild donor populations (Falace et al. 2018;Verdura et al. 2018). While the in-situ technique simulates the recruitment process by fixing fertile branches directly at the restoration site (Verdura et al. 2018), the ex-situ technique consists of cultivating seedlings in mesocosms to maximize recruitment and survival by setting the optimal culture conditions of temperature, light and nutrients (Falace et al. 2018;De La Fuente et al. 2019;Savonitto et al. 2021;Orlando-Bonaca et al. 2022). ...
As a result of several anthropogenic factors, Cystoseira sensu lato forests have declined or become regionally extinct in many coastal regions of the Mediterranean. Given the low natural recovery of lost populations, research efforts have been encouraged to develop sustainable and efficient restoration of macroalgal forests on a large scale. By promoting growth and fertility of collected thallus branches under controlled laboratory conditions, the availability of seedlings for restoration could be ensured without jeopardizing natural populations. Here we investigated the effect of a commercial algal biostimulant (AlgatronCifo®) on the photophysiology, growth and fertility of Gongolaria barbata (Stackhouse) Kuntze (Fucales, Phaeophyceae). In a factorial laboratory experiment, two different temperatures (10 ºC and 14 °C) and two culture media [i.e. seawater (SW) and Algatron (AT)] were tested. The photosynthetic performance of G. barbata doubled after three weeks of culture with AT, while it decreased by 25% when cultivated in SW. The highest photosynthetic performance and growth were achieved at 14ºC with AT, where fertile receptacles also developed, followed by seedling settlements. The thalli cultured in AT had similar or better photosynthetic performance than the initial control thalli. AT-cultured thalli had a greater ability to quench energy via photochemical pathways (qP) than those from the SW, which on the contrary, had higher levels of non-photochemical responses (qN, NPQmax). This limited photosynthetic performance was probably linked to the higher P-limitation experienced under that treatment. The algal biostimulant enhanced the physiological performance and induced fertility of G. barbata, demonstrating its valorization potential and setting a new path for improved restoration applications.
... Conservation actions should include detailed mapping and systematic monitoring, fisheries restrictions to increase the biomass of higher predators, especially sea bream and groupers, eliminate the overgrowth of grazers (Sala, 1997b;Shapiro Goldberg et al., 2021), and reduce all potential activities causing habitat destruction and pollution. Moreover, the application of long-term restoration actions in the more degraded areas, such as transplantation, ex situ out-planting, recruitment enhancement of canopy-forming macroalgae and other structural organisms, along with complementary actions of turf removal and herbivory management, are also needed to promote growth and recovery of these communities (Gianni et al., 2013;Verdura et al., 2018;De La Fuente et al., 2019;Guarnieri et al., 2020;Cebrian et al., 2021;Orlando-Bonaca et al., 2021). Yet again, to restore rocky reef communities as a whole, it is essential to increase scientific understanding regarding the mechanisms that determine the responses of different taxonomic and trophic groups to protection (Di Franco et al., 2021). ...
Mediterranean rocky reefs are undergoing regime shifts, from a structurally complex and diverse state dominated by canopy forming macroalgae to a degraded one characterised by low-lying turf or encrusting macroalgal species, due to increased anthropogenic pressure and climate change. Using data gathered from 89 sites across the entire Aegean Sea, this study aims to provide the most comprehensive health status assessment of shallow rocky reefs in the area, based on macroalgal community structure. Overall, 2520 benthic images were collected through photoquadrat sampling at 0, 5 and, 15 m depth. Five macroalgal and seven invertebrate morphofunctional groups, along with four substrate categories, were considered for community structure description. Health status was assessed using the reef-EBQI and EEI-c indices. Results indicate turf as the most widespread mac-roalgal group (36.8% average area cover), followed by encrusting calcareous (16.6%), shrubby (12.7%), articulated calcareous (8.9%), and canopy-forming algae (3.7%). Bare rock also occupied a substantial surface area (9.0%) with highest cover (13.8%) at 5 m. The area cover of canopy-forming algae was particularly low, ranging from 10% at 0 m to 0.1% at 15 m depth, on average. All depths pooled, according to the reef-EBQI index, the ecological status of the Aegean Sea was estimated to be 'Bad', mainly due to the bad ecological status of the 5 and 15 m stations. At 0 m depth, the status of the Aegean Sea was ranked 'Moderate' according to the reef-EBQI index and 'Good' according to the EEI-c index. The results underline the importance of considering a wide depth range when assessing the health status of rocky reef communities.
