Archives

Assisted Fertilization of Threatened Staghorn Coral to Complement the Restoration of Nurseries in Southeastern Dominican Republic

Abstract: Acropora cervicornis and Acropora palmata have declined dramatically in the Caribbean since the early 80’s, and are classified as Critically Endangered Species. To promote their recovery, restoration programs focusing on introducing fragmented specimens have been intensified. The current study was conducted in the south-eastern part of the Dominican Republic in September 2015 and August 2016. During these two periods, gametes from six mature colonies were collected from a five-year-old nursery with an area of 150 m2 at a depth of 12.5 m. 80% of the studied colonies spawned both years. Fertilization was assisted between 21:50 and 00:00 h, immediately after spawning. Fertilization and settlement rates were 90% and 50%, respectively. To our knowledge, this is the first scientific report on nursery propagated A. cervicornis spawning, assisted fertilization, larvae rearing and breeding.

Author: Calle-Trivino, J., C. Cortes-Useche, R.I. Sellares-Blasco, J.E. Arias-Gonzalez
Year: 2018
View More
Email for the full article: resilience@tnc.org
Regional Studies in Marine Science. doi:10.1016/j.rsma.2018.02.002

Share on FacebookTweet about this on TwitterEmail this to someone

Coral Reefs for Coastal Protection: A New Methodological Approach and Engineering Case Study in Grenada

Abstract: Coastal communities in tropical environments are at increasing risk from both environmental degradation and climate change and require urgent local adaptation action. Evidences show coral reefs play a critical role in wave attenuation but relatively little direct connection has been drawn between these effects and impacts on shorelines. Reefs are rarely assessed for their coastal protection service and thus not managed for their infrastructure benefits, while widespread damage and degradation continues. This paper presents a systematic approach to assess the protective role of coral reefs and to examine solutions based on the reef’s influence on wave propagation patterns. Portions of the shoreline of Grenville Bay, Grenada, have seen acute shoreline erosion and coastal flooding. This paper (i) analyzes the historical changes in the shoreline and the local marine, (ii) assess the role of coral reefs in shoreline positioning through a shoreline equilibrium model first applied to coral reef environments, and (iii) design and begin implementation of a reef-based solution to reduce erosion and flooding. Coastline changes in the bay over the past 6 decades are analyzed from bathymetry and benthic surveys, historical imagery, historical wave and sea level data and modeling of wave dynamics. The analysis shows that, at present, the healthy and well-developed coral reefs system in the southern bay keeps the shoreline in equilibrium and stable, whereas reef degradation in the northern bay is linked with severe coastal erosion. A comparison of wave energy modeling for past bathymetry indicates that degradation of the coral reefs better explains erosion than changes in climate and historical sea level rise. Using this knowledge on how reefs affect the hydrodynamics, a reef restoration solution is designed and studied to ameliorate the coastal erosion and flooding. A characteristic design provides a modular design that can meet specific engineering, ecological and implementation criteria. Four pilot units were implemented in 2015 and are currently being field-tested. This paper presents one of the few existing examples available to date of a reef restoration project designed and engineered to deliver risk reduction benefits. The case study shows how engineering and ecology can work together in community-based adaptation. Our findings are particularly important for Small Island States on the front lines of climate change, who have the most to gain from protecting and managing coral reefs as coastal infrastructure.

Author: Reguero, B. G., M.W. Beck, V.N. Agostini, P. Kramer, B. Hancock
Year: 2018
View More
Email for the full article: resilience@tnc.org
Journal of Environmental Management.

Share on FacebookTweet about this on TwitterEmail this to someone

A Potential Method for Improving Coral Self-Attachment

Abstract: Coral restoration is becoming increasingly important to sustain declining reefs. The survival rate of translocated corals in restoration projects is around 65%. This rate is, however, highly variable among projects, with success ranging from 0 to 90% and with detachment being a significant cause of mortality. Improving the speed and strength of coral self-attachment would increase survivorship in translocated corals. To address this need, we tested whether fragments of the scleractinian coral, Hydnophora rigida, artificially attached upside-down would self-attach more rapidly to the substratum than those artificially attached the right way up, which is the normal practice. We also tested the effect of three different diets (unfed, normal Artemia, and lipid-enriched Artemia) on coral growth and other biological responses. After 100 days, our results demonstrated that corals fixed upside-down grew significantly wider and faster over the substratum than corals fixed the right way up. A significantly higher number of fragments fixed upside-down were also able to self-attach and grow over the substratum (87%) compared with fragments fixed the right way up (58%). Neither the buoyant weight, height increment, symbiont density, chlorophyll, maximum quantum yield nor colour of corals fixed upside-down differed significantly from corals fixed the right way up. Our data shows that simply inverting the orientation of coral fragments may substantially accelerate the time for self-attachment and increase the survival rate of translocated corals in restoration projects.

Author: Tagliafico, A., S. Rangel, L. Christidis, B.P. Kelaher
Year: 2018
View More
Email for the full article: resilience@tnc.org
Restoration Ecology. doi:10.1111/rec.12698

Share on FacebookTweet about this on TwitterEmail this to someone

Bleaching Events Regulate Shifts From Corals to Excavating Sponges in Algae-dominated Reefs

Abstract: Changes in coral–sponge interactions can alter reef accretion/erosion balance and are important to predict trends on current algal-dominated Caribbean reefs. Although sponge abundance is increasing on some coral reefs, we lack information on how shifts from corals to bioeroding sponges occur, and how environmental factors such as anomalous seawater temperatures and consequent coral bleaching and mortality influence these shifts. A state transition model (Markov chain) was developed to evaluate the response of coral-excavating sponges (Cliona delitrix Pang 1973) after coral bleaching events. To understand possible outcomes of the sponge–coral interaction and build the descriptive model, sponge–corals were monitored in San Andres Island, Colombia (2004–2011) and Fort Lauderdale, Florida (2012–2013). To run the model and determine possible shifts from corals to excavating sponges, 217 coral colonies were monitored over 10 years (2000–2010) in Fort Lauderdale, Florida, and validated with data from 2011 to 2015. To compare and test its scalability, the model was also run with 271 coral colonies monitored in St. Croix, US Virgin Islands over 7 years (2004–2011), and validated with data from 2012 to 2015. Projections and sensitivity analyses confirmed coral recruitment to be key for coral persistence. Excavating sponge abundance increased in both Fort Lauderdale and St. Croix reefs after a regional mass bleaching event in 2005. The increase was more drastic in St. Croix than in Fort Lauderdale, where 25% of the healthy corals that deteriorated were overtaken by excavating sponges. Projections over 100 years suggested successive events of coral bleaching could shift algae–coral dominated reefs into algae–sponge dominated. The success of excavating sponges depended on the intensity of coral bleaching and consequent coral mortality. Thus, the proportion of C. delitrix excavating sponges is a sensitive indicator for the intensity and frequency of recent disturbance on Caribbean coral reefs.

Author: Chaves-Fonnegra, A., B. Riegl, S. Zea, J.V. Lopez, T. Smith, M. Brandt, D.S.Gilliam
Year: 2017
View More
Email for the full article: resilience@tnc.org
Global Change Biology 24(2). doi:10.1111/gcb.13962

Share on FacebookTweet about this on TwitterEmail this to someone

Corals in Healthy Populations Produce More Larvae Per Unit Cover

Abstract: In coral reef conservation and management, the prevailing metric of reef health is percent coral cover, a measurement commonly used with the assumption that each
unit of live coral tissue has equivalent ecological value. Here we show that the
reproductive output of a coral population is not proportional to the cover of coral present.
Instead, when compared to declining populations nearby, high cover coral populations
produced up to four times more larvae per square centimeter of tissue, resulting in up to
200 times higher larval production per square meter of reef. Importantly, corals that
produced more larvae did not produce smaller larvae, as predicted by resource allocation
theory. Instead, higher fecundity corresponded to higher energetic lipid reserves in higher
cover coral populations. In the wake of unprecedented global coral bleaching, our
findings suggest that the largest reductions in coral reproduction may occur when corals
are lost from previously healthy populations.

Author: Hartmann, A.C., K.L Marhaver, M.J Vermeij
Year: 2017
View Abstract
http://onlinelibrary.wiley.com/doi/10.1111/conl.12410/full
Email for the full article: resilience@tnc.org

Conservation Letters. doi:10.1111/conl.12410

Share on FacebookTweet about this on TwitterEmail this to someone

Adaptation Design Tool for Natural Resource Management – Minnesota, 2017

DSC_0176

The Reef Resilience Network partnered with NOAA and EPA to host a 1.5 hour training on Adaptation Design Tool for Natural Resource Management at the National Adaptation Forum on May 11, 2017. The training session provided an interactive introduction to the Adaptation Design Tool that walks practitioners through steps for adjusting the design of their management activities to be more climate-smart. Participants got a brief ‘how to’ on the tool, along with an illustrative case study presentation, and hands-on work to apply adaptation design to example management activities for Puerto Rican coral reefs. A more extensive version of the Adaptation Design Tool will be launched this summer in the form of an online course and instructor-led training as part of the Reef Resilience Toolkit.
Share on FacebookTweet about this on TwitterEmail this to someone

Synergistic Impacts of Global Warming on the Resilience of Coral Reefs

There have been few investigations on the effects of climate change on coral reef resilience. This study focuses on how a single climate driver, sea surface temperature (SST), can both chronically (growth rate) and acutely (bleaching) affect coral reefs. A spatially explicit model was used to simulate the effects of both chronic and acute thermal stress when acting together and separately. As expected, when thermal stress does not affect reefs, coral cover increases over time. Acute thermal disturbances were found to considerably reduce coral cover and reduce reef resilience. Chronic thermal disturbances lowered resilience, but at a much smaller magnitude than those that were acute. When acting together, acute and chronic stressors act in synergism to reduce resilience. In moving forward in a changing climate, the authors argue that it is imperative to consider synergism among stressors when thinking about the future impact of climate change on reef resilience. Additionally, since reef state, or percent coral cover, and reef resilience are largely unrelated, management efforts should not be solely focused on coral cover as resilience episodes may go unnoticed. It is reef resilience that will ultimately help to identify and hopefully repair ecosystem dysfunction before any stress or damage inflicted becomes permanent.

Author: Bozec, Y-M. and P.J. Mumby
Year: 2015
View Full Article

Philosophical Transactions of the Royal Society B 370: 20130267

Share on FacebookTweet about this on TwitterEmail this to someone

Bright Spots Among the World’s Coral Reefs

This study suggests that we can learn a significant amount about coral reef decline by identifying outliers. These outliers include areas where ecosystems performed better than expected, bright spots, and areas where ecosystems performed worse than expected in the presence of local environmental and socioeconomic pressures, dark spots. Data was compiled from more than 2500 reefs worldwide and a Bayesian hierarchical model was developed to determine the relationship between fish biomass of standing stocks related to 18 different environmental and socioeconomic drivers. 15 bright spots and 35 dark spots were identified. Bright spots were characterized by strong sociocultural institutions, high levels of local engagement in management, high dependence on marine resources, and beneficial environmental conditions. Dark spots saw high levels of fish capture, innovative storage technology, and a recent history of environmental shock. These findings suggest that bright spots can be used to broaden the discussion on coral reef conservation, help target areas other than those that are remote and pristine, and help to renew the focus of management on the socioeconomic drivers that impact reef condition. Dark spots will help identify strategies to avoid in coral reef management, while bright spots may be a key in reef resilience in the future as they will help create a long term sustainability plan for reefs impacted by layers of stress.

Author: Cinner, J.E., C. Huchery, M.A. MacNeil, N.A.J. Graham, T.R. McClanahan, J. Maina, E. Maire, J.N. Kittinger, C.C. Hicks, C. Mora, E.H. Allison, S.D. Agata, A. Hoey, D.A. Feary, L. Crowder, I.D. Williams, M. Kulbicki, L. Vigliola, L. Wantiez, G. Edgar, R.D. Stuart-Smith, S.A. Sandin, A.L. Green, M.J. Hardt, M. Beger, A. Friedlander, S.J. Campbell, K.E. Holmes, S.K. Wilson, E. Brokovich, A.J. Brooks, J.J. Cruz-Motta, D.J. Booth, P. Chabanet, C. Gough, M. Tupper, S.C.A. Ferse, U.R. Sumaila, and D. Mouillot
Year: 2016
View Abstract
Email for the full article: resilience@tnc.org

Nature 535: 416-419. doi:10.1038/nature18607

Share on FacebookTweet about this on TwitterEmail this to someone