Coral Nurseries Research Articles

Effects of nursery table slope orientation on coral survival and growth

ABSTRACTTransplanting nursery-reared corals is among one of the most common approaches to assist the recovery of degraded reefs. The nursery phase is considered essential for providing a favourable environment for coral fragments to grow into suitable sizes before transplantation to natural reef substrates. Several types of coral nursery designs have been used, but the effect of nursery table slope orientation on survival and growth of coral fragments has not been fully evaluated. Survival and growth of coral fragments from four species (Pectinia paeonia, Podabacia crustacea, Pocillopora acuta, Merulina ampliata) on three inclinations of nursery table top (horizontal (0°), diagonal (45°) and vertical (90°)) were monitored over six months. The effects of slope orientation on survival and growth of fragments were not significant among species except P. acuta, for which survivorship and growth decreased significantly only on vertical nursery tables. The conditions required for coral propagation, such as slope orientation of nursery tables and the initial size of fragments, clearly differ among species due to their inherent attributes and restoration success will greatly benefit from empirical studies derived from a wider range of species.

In situ nurseries enhance coral transplant growth in sedimented waters

ABSTRACTIn situ nurseries have been a crucial part of coral reef restoration initiatives for the past two decades. However, the advantages over direct transplantation in sedimented waters has yet to be examined. In the present study, we showed that Pachyseris speciosa and Pocillopora damicornis fragments reared in in situ nurseries (NR) in Singapore’s sedimented waters grew significantly faster (by three to five times) than those which were directly transplanted (DT) onto the substrates. The increased growth rate during the nursery phase augmented the size of NR transplants, and had a flow-on effect on their performance during the post-transplantation phase. Overall, the maximum diameter of the NR transplants was 1.8–2.7 times larger than DT transplants after 11 months. The growth enhancement of the nursery-reared transplants improved the cost-effectiveness of our restoration effort: the estimated cost per centimetre growth of NR transplants was one-fifth of the DT corals despite the additional costs incurred to construct the nurseries. These results highlight that coral nurseries are beneficial to reef restoration in chronically sedimented waters.

Tiling the reef – Exploring the first step of an ecological engineering tool that may promote phase-shift reversals in coral reefs

Phase shifts from coral- to algal-dominated reefs have grave effects on reef biodiversity and key ecosystem functions, further influencing management approaches that have generated fewer returns than desired. Harnessing the ability of corals to ‘self-anchor’ to substrates and of tissue fusions between isogeneic fragments, we develop here a novel ecological engineering approach based on the 2D Coral Preparative (2D-CP) tool. Using this tool we propose to create flat, two dimensional coral units that are first grown in a mid-water coral nursery and then transplanted to overlay phase-shifted coral reef surfaces as floor tiles. Here, we assess the feasibility of the 2D-CP’s first stage- growth in the nursery. Ten coral colonies from each of the species: Stylophora pistillata, Pocillopora damicornis and Cyphastrea spp. were collected from localities at the northern Gulf of Eilat (Red Sea, Israel), fragmented into nubbins and glued onto flat surfaces (CDs) to create 235 2D-CP units (32 nubbins/unit). All 2D-CPs were hung in a mid-water coral nursery, in both horizontal and vertical positions, and were digitally photographed once a month for a year. Images of each 2D-CP were used to determine the percentages of live coral tissue coverage on the substrates and the nubbins’ survival percentage. Results revealed high survival rates, with >80% of the 2D-CPs possessing live coral tissues at 12 months post setup (mps). The nubbins of all three species displayed an extensive 2D growth on the substrates, and as of 6–7 months (species and genotype specific) many of the 2D-CPs were completely covered with coral tissue (20% of all the 2D-CPs showed >100% coral coverage at 12mps). The coral coverage of S. pistillata and P. damicornis 2D-CPs was significantly higher in the vertical placement position, 1.5 and 3 times, respectively.Overall, these results imply that the 2D-CP units can be successfully grown in a coral nursery for the purpose of creating ‘live tiles’ that can be placed directly over a denuded reef covered by turf algae, a novel ecological engineering tool to be used for coral-algae phase shifts reversals. We further anticipate that even in completely/partially dead 2D-CP units, newly exposed calcium carbonates would be expended as preferable substrates for either coral larval recruitment or coralline algae growth, boosting reef rehabilitation.

Evaluation of staghorn coral (Acropora cervicornis, Lamarck 1816) production techniques in an ocean-based nursery with consideration of coral genotype

Staghorn coral Acropora cervicornis is an important framework-building species that has declined severely throughout the Caribbean since the early 1980s. This species is now widely cultured in ocean-based nurseries to restore degraded populations. A variety of techniques have been adopted to grow A. cervicornis for restoration purposes, however the effect of each of these methods on nursery-reared corals is not well-understood. In particular, systematic evaluation of nursery-reared A. cervicornis between water column-suspended and benthic-attached culture methods is lacking. To better understand the effect of these techniques, a one-year A. cervicornis propagation experiment in the Florida Keys was conducted to compare growth, condition, and survivorship between common suspended (i.e. tree) and benthic-attached (i.e. block) grow-out methods. The effect of coral genotype on growth was also considered. Colonies were measured and monitored monthly from December 2014 until November 2015, when only three colonies had survived an extreme bleaching event. Colonies on trees grew up to three times faster than those on blocks and the location of colonies on trees did not affect growth. Genotype had a significant effect on colony growth, which was consistent across grow-out methods. Interestingly, colonies grown on blocks bleached sooner but survived longer than those on trees. These findings contribute to a growing understanding of A. cervicornis nursery culture, and could aid in the selection of culture methods and genotypes for coral nurseries throughout the wider Caribbean.

Assessment of wild and restored staghorn coral Acropora cervicornis across three reef zones in the Cayman Islands

Interest in restoring staghorn coral Acropora cervicornis has grown following the widespread decline of this species in recent decades. To date, thousands of nursery-reared A. cervicornis have been outplanted to restore degraded reefs, but survivorship and growth among outplanted colonies can be spatially variable. In particular, data on distribution of remnant wild populations and outplant performance in varying reef zones is lacking. To address this gap, we conducted a study to characterize existing wild populations and assess performance of nursery-reared, outplanted A. cervicornis among three reef zones of varying depth at Little Cayman Island: the shallow back reef (0–3 m), the intermediate spur-and-groove reef (8–15 m), and the deep reef terrace (>15 m). Wild populations of A. cervicornis were present in each reef zone, and colony height and prevalence of predation by Stegastes spp. were highest in the intermediate zone. For outplanted A. cervicornis, survivorship differed among sites and was lowest for outplants in the deep zone during the 85-day observation period. Post-outplant growth and branching was lowest among outplants in the shallow zone due to high rates of colony breakage. Following the conclusion of the study, a mortality event occurred in which 90% of outplants at the shallow plots died during a period of elevated sea temperature. The information provided in this study suggests that intermediate spur-and-groove reefs are optimal for outplanting activities in Little Cayman using existing restoration methods. These data could be useful for coral restoration practitioners and government agencies in the Caribbean, particularly the Cayman Islands, which is actively expanding its coral nursery program. New strategies must be developed to improve restoration outcomes in shallow and deep zones.

Elaborating an eco-engineering approach for stock enhanced sexually derived coral colonies

Despite all traditional conservation management efforts, coral reefs worldwide continue to face a future of degradation and destruction. Current studies call for the augmentation of coral reef management with restoration practices, particularly alternative reef management approaches, such as the ‘coral gardening’ tenet of active reef restoration. This includes the stock creation of sexually derived coral colonies and their mariculture in mid-water coral nurseries. In this study, single and aggregated (resulting in non-fusion and chimeric entities) spats of the branching coral Stylophora pistillata were studied. Planula larvae were settled and spat were reared ex situ for 50–75days before they were transplanted to the in situ mid-water nursery in Eilat, Israel, where they were followed for up to two years, showing a very low (<2%) detachment rate. Spats were cultured in horizontal and vertical orientations, in caged (for the first 9 nursery months) and noncaged scenarios, and on two nursery beddings (nets and ropes). Caging of horizontally situated young spats on the net substrate resulted in the highest survival (>80% after 2years). Corals farmed in a vertical orientation had the lowest survival rate of the caged experiments (36.7%) but showed that chimeric/aggregated entities performed significantly better than the single colonies. The uncaged experiments had low (32.7%) to zero surviving spats after two years in situ. The surviving colonies reared under the uncaged conditions were significantly smaller than the caged colonies after the 9months in situ ‘caging period’. Generally, the placement of the young spats in the mid-water nursery resulted in high growth rates: After two years in situ, coral colony diameter increased from 0.1cm to 8.16±1.58cm for the vertical caged scenario, and 7.08±1.72cm, 7.02±1.48cm for the two caged horizontal designs (HN and HR). This is nearly twice the growth rate observed in natal colonies. The midwater coral nursery is a much cheaper solution for growing corals compared to ex situ water tables, which require high maintenance and expensive facilities to mimic in situ conditions. Non-caged coral stocks showed reduced survival and growth rates, similar to previously published results. The culturing of caged spats in a horizontal position in a midwater nursery exponentially augment survival and growth rates, thus enhancing stock creation yields. This offers new possibilities for creating stocks of sexually derived spats from eco-engineering coral species such as S. pistillata.

Intraspecific variation in phenotype among nursery-reared staghorn coral Acropora cervicornis (Lamarck, 1816)

Although genetic diversity is recognized as an important consideration for coral restoration, genotypes for use in restoration are not typically selected based on an evaluation of phenotype. Systematic documentation of phenotypic variability within coral nurseries could inform restoration efforts. To quantify differences in phenotype, ten known genotypes of Acropora cervicornis in an established coral nursery in the Florida Keys were selected for study. Twelve 5-cm replicate colonies of each genotype were individually tagged for identification and suspended from four identical PVC tree structures within the nursery for grow-out. Total linear extension (TLE) and number of branches were measured at approximately 45-day intervals for a period of 13months. Buoyant weight was determined for each colony initially and after five and 13months in order to quantify calcification. Sub-lethal bleaching was observed among experimental colonies following a natural thermal stress event, and significant differences in bleaching prevalence were present among genotypes. At the conclusion of the study, significant differences in all growth parameters were detected among genotypes. Specific growth rate across genotypes decreased following bleaching. The ratio of buoyant weight to TLE varied among genotypes and decreased with increasing TLE, suggesting a potential tradeoff between extension and skeletal density in nursery-reared A. cervicornis. Phenotypic variation documented in this study has implications for nursery management and may be useful in selecting genotypes for A. cervicornis population enhancement.

Reef-scale trends in Florida Acropora spp. abundance and the effects of population enhancement.

Since the listing of Acropora palmata and A. cervicornis under the US Endangered Species Act in 2006, increasing investments have been made in propagation of listed corals (primarily A. cervicornis, A. palmata to a much lesser extent) in offshore coral nurseries and outplanting cultured fragments to reef habitats. This investment is superimposed over a spatiotemporal patchwork of ongoing disturbances (especially storms, thermal bleaching, and disease) as well as the potential for natural population recovery. In 2014 and 2015, we repeated broad scale (>50 ha), low precision Acropora spp. censuses (i.e., direct observation by snorkelers documented via handheld GPS) originally conducted in appropriate reef habitats during 2005–2007 to evaluate the trajectory of local populations and the effect of population enhancement. Over the decade-long study, A. palmata showed a cumulative proportional decline of 0.4 –0.7x in colony density across all sites, despite very low levels of outplanting at some sites. A. cervicornis showed similar proportional declines at sites without outplanting. In contrast, sites that received A. cervicornis outplants showed a dramatic increase in density (over 13x). Indeed, change in A. cervicornis colony density was significantly positively correlated with cumulative numbers of outplants across sites. This study documents a substantive reef-scale benefit of Acropora spp. population enhancement in the Florida Keys, when performed at adequate levels, against a backdrop of ongoing population decline.

Coral nurseries as habitats for juvenile corallivorous butterflyfish

Coral nurseries as habitats for juvenile corallivorous butterflyfish

Coral restoration in Singapore’s sediment-challenged sea

Singapore’s coral reefs have been exposed to five decades of increased sedimentation that reduced underwater visibility from over 10 m in the early 1960s to under 2 m today. The lower depth limit of scleractinian coral growth moved up from 10 m to 6 m, while live coral cover decline is less apparent now than in the early decades of augmented sediment loading. Coral community structure has changed with dominance shifting to more low-light tolerant species such as those of the genera Pectinia and Turbinaria. Reef restoration to increase coral cover of degraded reefs and initiate colonisation of non-reef areas is considered to be viable following observations of predictable mass spawning events, recruitment and vigorous growth, but the techniques employed need to account for the high sediment conditions and destabilised reef substrate. The deployment of fibreglass artificial reef units increased opportunities for coral establishment, and supported at least 106 reef taxa, including 29 scleractinian genera after 10 years. As vital components of restoration, coral nurseries comprising mesh-net platforms raised above the reef floor prevented sediment accumulation and smothering, and enabled the rearing of coral fragments and juveniles with reduced mortality. This included the nurturing of ‘corals of opportunity’ (naturally fragmented pieces of live coral lying on the reef bed as well as recruits settled on loose rubble), which would otherwise be killed by sedimentation. Transplants of massive or encrusting species displayed higher survival over branching ones. Restoration strategies need to be adapted to changed environmental conditions caused by anthropogenic disturbances.

Coral translocation and farming as mitigation and conservation measures for coastal development in the Red Sea: Aqaba case study, Jordan

Coastal development is often at odds with coral reef conservation. In Aqaba, Jordan, authorities proposed a plan to relocate the existing port services to a new area on Al-Dirreh Bay towards the southern end of the Gulf of Aqaba. As a mitigation measure, 7000 endangered coral colonies were moved from Al-Dirreh and transplanted into degraded reef sites in Aqaba Marine Park. Sample survival and linear growth rates were determined biannually for 2 years and compared to growth rates at a control site. The overall survival rate for the transplanted colonies was estimated to exceed 87 % and the linear growth rates of the 16 species studied showed very similar values to colonies of the same species at the control site. Three species, Goniastrea edwardsi, Acropora arabensis and Stylophora pistillata, demonstrated more than 1 cm of linear growth per year. In addition, a nursery of coral nubbins from three species, Acropora hemprichii, S. pistillata and Pocillopora damicornis, was established to be a sustainable source of fully grown colonies. Their survival and linear growth rates were also measured over the 2-year period. The overall survival rate of the nubbins was 88 %, and the annual linear growth rate ranged from 0.32 cm for A. hemprichii to 0.99 cm for S. pistillata. High survival and linear growth rates indicate that the transplantation site selection and the techniques employed were successful. The results of this work support the premise that endangered coral colonies can be translocated to other reef areas and that coral nurseries can be set up to produce multiple fully grown colonies for future reef rehabilitation projects.

Coral Reef Restoration using Nursery-Reared Coral Fragments in a LGU-Academe Ushered Community Project in Masbate (Philippines)

With the declining state of Philippine coral reefs, the need for conservation and rehabilitation efforts are deemed crucial to sustaining ecological, biological and economic recovery in the reef system. However, there is yet a concrete and workable policy to be implemented in restoring and rehabilitating our reef areas aside from establishment of marine protected area (MPA). Here, we explored the prospects of coral restoration by demonstrating experiences in San Fernando, Masbate (Ticao Island) combined with the practices of the National Coral Restoration Program. In this project, some 20,000 coral nubbins utilizing ‘corals of opportunities’ were reared in 40 coral nursery units (CNUs) for six months and achieved 80% survival. They were then out-planted (c. 20,000 sq m) inside an MPA to ensure their protection and increase in live cover. The fragments were attached to dead corals using epoxy or tied in concrete nails using cable ties. Four coral genera were used namely Acropora, Seriatopora, Pocillopora, and Stylophora. About 70% coral survival was achieved after two months of transplantation. Involvement of the LGU, community and the private sector is crucial to project success. Results of the transplantation indicated effectiveness and viability of the CNU system to complement coral transplantation.

Development of a coral nursery as a sustainable resource for reef restoration in Abu Al Abyad Island, Abu Dhabi, United Arab Emirates, Arabian Gulf

Development of a coral nursery as a sustainable resource for reef restoration in Abu Al Abyad Island, Abu Dhabi, United Arab Emirates, Arabian Gulf

BOHOL, PHILIPPINES: BUILDING PARTNERS FOR CORAL REEF RESTORATION IN PANGLAO ISLAND

Panglao Island is one of the tourist destin ations in the Philippines due to its white sand beaches, spectacular coral formations, beautiful reef fishes and crystal clear waters. Tourist arrival in 2012 noticeably decreased according to the dive shop operators and hotel and restaurant operators. Cor al reefs damaged due to human and natural factors. Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD) of the Department of Science and Technology (DOST) implemented the Filipinnovation on Coral Reef Restora tion Program in collaboration with the University of San Carlos (USC), Cebu City and Bohol Island State University (BISU), Candijay Campus to manage the Pilot Technology Demonstration on Coral Reef Restoration in Panglao, Bohol. The ultimate goal of the project was to restore the degraded coral reefs through innovative means while maintaining partnerships between the local government units and private sectors which directly benefiting the coral ecosystems. The project team members were able to complete the deployment of 40 coral nursery units (CNUs) underwater in the month of September 2012. About 20,000 coral fragments were planted directly to the substrate using two techniques: 1) underwater epoxy as coral adhesive; and 2) nail and cable tie method. Tagged coral samples, it was found that the survivability of the transplanted coral was at 80% but decreased significantly with the presence of corallivores such as crown of thorns seastars, Acanthaster plancii and the snail that feeds on corals, Drupella cornus . Data gathered from the CNUs, it was ascertained that Acropora nobilis was a fast growing acroporid species capable of growing at .37 cm in three weeks or at 5.76 cm/ year, with all else assumed being linear. The project invites and encourages dive shop o perators, hotel and restaurant owners, local government units and non government organization’s officials in Bohol province to sustain the project.

Growth of Acropora formosa Fragments in In-situ Coral Nurseries at Polhena Reef, Matara, Sri Lanka

Coral reef are one of the most valuable coastal ecosystems, yet they are under various threats. Present study was to investigate the growth of Acropora Formosa fragments in in-situ coral nurseries of Matara Pollhena reef located on the southern coast of Sri Lanka. Study was conducted between April to November 2014. Eight different sites representing open sea and reef lagoon were selected to compare growth of A. formosa fragments in coral nurseries. Seawater quality parameters such as salinity, water temperature, pH, dissolved oxygen, nitrates, and phosphates were measured in monthly intervals. In addition, sedimentation rate was determined by deploying sediment traps. The highest mean extension growth rate for A. formosa (1.07±0.05 cm per month) was recorded at a site in the reef lagoon close to Nilwala river out fall and lowest mean extension rate (0.20±0.06 cm per month) was also recorded in reef lagoon more southward to the Nilwala river outfall. There was significantly different growth rates among eight sampling sites (t-test, p<0.05). The mean extension growth rates for open sea sites were higher when compared with reef lagoon sites (0.41±0.09 cm per month, 0.72±0.07 cm per month) respectively. The survival rates of coral fragments were ranged from 85.71% to 65.08%. The results highlight that the A. formosa shows differential growth rates in reef lagoon and open sea areas. Further, A. formosa has higher growth rate compared to other coral species and also can withstand higher sedimentation rates. Keywords: Acropora formosa, Coral growth, Coral nurseries, Polhena reef

Assessing an abridged nursery phase for slow growing corals used in coral restoration

The continued decline of coral reefs worldwide due to natural and anthropogenic drivers necessitates the development of effective restoration schemes. Two of the approaches frequently used nowadays are (1) the direct transplantation of coral fragments/colonies to degraded reefs; and (2) the “coral gardening” approach, which supports coral transplantation only following an intermediate nursery phase, where corals are farmed until reaching suitable sizes. Both approaches are evaluated for the quality of transplanted coral material, employing two field experiments on fragments from Echinopora lamellosa and Merulina scabricula, non-branching, slow growing coral species (Scleractinia) commonly residing in the reef of Bolinao, Pangasinan, northwestern Philippines. Each experiment included an abridged (shortened) nursery phase of 1 year. The first experiment assessed the performance of two newly collected groups of coral fragments, one reared in situ within a coral nursery and the second directly transplanted to coral-denuded bommies. The second experiment evaluated the post-transplantation performance of nursery-reared colonies against similar-sized freshly collected coral fragments, both transplanted onto denuded bommies. Growth rate (buoyant weight and size increments), survivorship and attachment were compared within each experiment. While in the first experiment, clear patterns for enhanced growth, survivorship and attachment rates were recorded in the nursery farmed fragments as compared to directly transplanted nubbins, no such differences were found between the two coral groups in the second experiment, indicating that short-term nursery farming of slow growing corals does not improve their post-transplantation performance. However, since growth and survivorship during the nursery phase are enhanced, an abridged nursery farming stage may serve as an ecological engineering tool for the production of augmented numbers of coral material for transplantation. Follow-up studies such as testing the fragment size along with nursery time for various coral species of different growth patterns are indispensable for the improvement of the “coral gardening” protocols.

Reef fishes recruited at midwater coral nurseries consume biofouling and reduce cleaning time in Seychelles, Indian Ocean

In coral reef restoration, coral gardening involves rearing coral fragments in underwater nurseries prior to transplantation. These nurseries become fish-aggregating devices and attract biofouling. We hypothesised that: (1) the presence of corals at a nursery is critical to recruit fish assemblages and (2) the recruited fish assemblages control biofouling, reducing person-hours invested in nursery cleaning. Three midwater coral nurseries were deployed at 8 m depth for 27 months within the marine protected area of Cousin Island Special Reserve, Seychelles, Indian Ocean. Each nursery consisted of a 6 m×6 m PVC pipe frame, layered with a recycled 5.5-cm-mesh tuna net. Human cleaning effort was calculated based on daily dive logs. Nursery-associated fish assemblages and behaviour were video-recorded prior to harvesting corals after a 20-month growth period and seven months post-coral harvesting. The density (ind. m–2) of blue-yellow damselfish Pomacentrus caeruleus was 12–16 times higher when corals were present than when corals were absent at the nurseries. Fish assemblages recruited into the nurseries included three trophic levels, from herbivores to omnivores, in six families: Ephippidae, Pomacentridae, Labridae (Scarinae), Gobiidae, Siganidae and Monacanthidae. Higher abundance of large fish (total number of individuals) resulted in 2.75 times less person-hours spent in nursery cleaning. These results have important implications for cost-effective coral reef restoration.

Demography of the threatened coral Acropora cervicornis: implications for its management and conservation

Populations of Acropora cervicornis have collapsed throughout the Caribbean. This situation has prompted the initiation of many restoration efforts; yet, there are insufficient demographic data and analyses to effectively guide these initiatives. In this study we assessed the spatiotemporal variability of A. cervicornis vital rates. We also developed a population matrix model to (1) evaluate the risk of population extinction, (2) estimate population growth rates (λ) considering different rates of colony fragmentation and fragment survival, (3) determine the demographic transition(s) that contribute the most to spatiotemporal differences in λs, and (4) analyze the effectiveness of outplanting coral fragments of different sizes. The model was parameterized by following the fate of 300 colonies from 2011 to 2013 at two localities in Puerto Rico. Demographic transitions varied spatiotemporally, with a significant interaction between location and time period on colony fate. Spatiotemporal variations in λ were also observed. During the first year, populations exhibited λs below equilibrium (0.918 and 0.948), followed by a dramatic decline at both sites (0.535 and 0.709) during the second year. The lower λs were caused by a decrease in the probability of stasis of large-sized colonies coupled with lack of sexual recruits and a meager contribution of asexual recruitment. Spatial variations in λs were largely due to differences in the probability of medium-sized colonies advancing to the largest size class. The viability analysis forecasts that the populations will reach quasi-extinction levels of 25 % of the initial population size in ≤16 yrs. Numerical simulations indicate that outplanting fragments ≥250 cm in total linear length (TLL) would result in a higher asymptotic population size than outplanting smaller fragments. We argue, however, that transplanting colonies ≤100 cm TLL will be a better management strategy because they can be produced faster and in higher numbers at coral nurseries.

Optimizing the productivity of a coral nursery focused on staghorn coral Acropora cervicornis

The rapid decline of the staghorn coral Acropora cervicornis throughout the Carib- bean prompted the development of coral gardening as a management strategy to restore wild stocks. Given that coral gardening relies on propagating corals collected from wild donor colonies, it is imperative to optimize growth within a nursery to reduce dependence on wild collections. This study determined the maximum amount of coral that may be clipped from a colony during propagation without causing mortality or decreased growth. We applied 3 experimental treat- ments to 12 nursery-reared staghorn corals, in which 25, 50, or 75% of the colony's total biomass was removed and fragmented to create additional, smaller fragments. Four additional colonies served as unfragmented controls. Treatment had no effect on colony productivity, defined as the ratio of new tissue growth to initial colony size, over 87 d. Similarly, treatment had no effect on the rate at which colonies developed new branches. Results indicate that 75% of the biomass of staghorn colonies may be removed without affecting their growth. We anticipate that our obser- vations will have practical applications for maximizing propagation of staghorn coral within nurs- eries throughout the wider Caribbean while minimizing the impact of this management measure on remnant wild populations.

Climate Change and Active Reef Restoration—Ways of Constructing the “Reefs of Tomorrow”

The continuous degradation of coral reef ecosystems on a global level, the disheartening expectations of a gloomy future for reefs’ statuses, the failure of traditional conservation acts to revive most of the degrading reefs and the understanding that it is unlikely that future reefs will return to historic conditions, all call for novel management approaches. Among the most effective approaches is the “gardening” concept of active reef restoration, centered, as in silviculture, on a two-step restoration process (nursery and transplantation). In the almost two decades that passed from its first presentation, the “gardening” tenet was tested in a number of coral reefs worldwide, revealing that it may reshape coral reef communities (and associated biota) in such a way that novel reef ecosystems with novel functionalities that did not exist before are developed. Using the “gardening” approach as a climate change mediator, four novel ecosystem engineering management approaches are raised and discussed in this article. These include the take-home lessons approach, which considers the critical evaluation of reef restoration outcomes; the genetics approach; the use of coral nurseries as repositories for coral and reef species; and an approach that uses novel environmental engineering tactics. Two of these approaches (take-home lessons and using coral nurseries as repositories for reef dwelling organisms) already consider the uncertainty and the gaps in our knowledge, and they are further supported by the genetic approach and by the use of novel environmental engineering tactics as augmenting auxiliaries. Employing these approaches (combined with other novel tactics) will enhance the ability of coral reef organisms to adaptably respond to climate change.