REEF e-talks

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September 2022

Underwater photogrammetry reveals new links between coral reefscape traits and fishes that ensure key functions

Isabel Urbina-Barreto | Postdoctotal Researcher Future Maore Reefs Project, Institute of Research for Development (IRD)

21st September 2022 | 11:00 a.m. (CET) / 1:00 p.m. (RET)

 

 Isabel Urbina Barreto                                                                                                                                                       Reef E Talks BUTTON UPDATE

Abstract

Maintaining key functions of coral reefs is vital for the persistence of these ecosystems as well as for securing the goods and services that they provide in the Anthropocene. Underwater photogrammetry by Structure from Motion (SfM) allows the quantification of novel habitat descriptors that may be particularly relevant in assessing key reefscape traits, that is, physical and ecological characteristics of coral reef habitats. Here, we combined this new technology with fish surveys to explore how reefscape traits shape the functional structure of reef fish assemblages around three environmentally contrasted islands of the Indo-Pacific (Europa Island, Reunion Island, and New Caledonia). At 24 sites, habitat descriptors were computed from digital elevation models (DEM) and orthomosaics, while reef fish assemblages were assessed by visual census and video footage. Four habitat descriptors were marginally correlated and presented low variance inflation factor (VIF) values, thus being the most complementary descriptors: surface complexity, total shelter capacity, Shannon Shelter Index, and total coral cover. Linear mixed models (LMM) were used to explore the relationships between these habitat descriptors and four key fish functional entities: prey, planktivores, grazers, and predators. For each model, the variance explained (i.e., marginal R2) was significantly higher when considering multiple predictors, including the novel three-dimensional descriptors (i.e., total shelter capacity and Shannon Shelter Index). The habitat descriptors quantified from underwater photogrammetry outputs (i.e., DEM and orthomosaics) provide easily available data to assess key reefscape traits and predict fish assemblage structure in coral reef ecosystems. This trait-based functional approach allows consistent assessment of the links between these descriptors from local to regional scales. Considering the global coral reef crisis and the increasing availability of world-reef photogrammetric surveys, this new technology should be key to bringing solutions to 21st-century conservation issues.

Authors

Urbina-Barreto, Isabel; Elise, Simon; Guilhaumon, François; Bruggemann, J Henrich; Pinel, Romain; Kulbicki, Michel; Vigliola, Laurent; Mahamadaly, Gerard Moutham; Vincent; Facon, Mathilde; Bureau, Sophie; Peignon, Christophe; Dutrieux, Eric

Profile

I am a passionate marine biologist, interested in the application of new technologies for conservation programs of coastal/marine ecosystems. I am particularly concerned with monitoring methods and conservation of coral reef ecosystems. My aim is to understand and evaluate it effectively, and to establish optimal tools that improve the management of such ecosystems. I understand the importance of interdisciplinary approaches and the need for new scientific disciplines such as environmental restoration.

Please note that, subject to the presenters's approval, all reef e-talks will be recorded and uploaded onto our dedicated YouTube channel and that by registering for the talks you provide us with your explicit consent to do so. The uploaded footage will contain the slideshow of the presenter and his/her image as displayed by his/her video camera and exclude the questions & answers sessions. You may withdraw your consent by cancelling your registration (following the cancel link at the bottom of your registration confirmation email) or sending an email to This email address is being protected from spambots. You need JavaScript enabled to view it.. Please note that you will not be allowed to take part in the talks if you withdraw your consent before they start and that after the recording has been published, we cannot remove it from YouTube. Click here to learn more about ZMT's privacy policy for online seminars.


Oktober 2022 

Ocean warming impacts on coral larval dispersal patterns and connectivity                                                                                                    Joana Figueiredo | Nova Southeastern University

19th October 2022 | 3:00 p.m. (CET) / 9:00 a.m. (EST)

Joana Figueiredo Reef E Talks BUTTON UPDATE

Abstract

Climate change will alter many aspects of the ecology of organisms, including dispersal patterns and population connectivity. Understanding future dispersal patterns of key ecosystem species, such as corals, is essential to predict future species distributions, potential for adaptation, and to design effective networks of protected areas that could maximize coral reefs’ chances of persistence. In marine environments, dispersal is often accomplished by larvae, and at higher temperatures, larvae develop faster, but suffer higher mortality, making the effect of temperature on dispersal difficult to predict. Using a high-resolution (as high as 200m) empirically-calibrated biophysical model of coral larval dispersal for the southern Great Barrier Reef, we show that a 2°C warming will increase local retention, decrease the distance larvae disperse, and reduce number of connections between reefs, whereas projected changes in large-scale currents have limited effects. Collectively, these shifts imply that 2°C of warming will reduce inter-reef connectivity, hampering recovery after disturbances and reducing the spread of warm-adapted genes. Such changes make protections more effective locally, but may require reducing spacing of protected areas.

Please note that, subject to the presenters's approval, all reef e-talks will be recorded and uploaded onto our dedicated YouTube channel and that by registering for the talks you provide us with your explicit consent to do so. The uploaded footage will contain the slideshow of the presenter and his/her image as displayed by his/her video camera and exclude the questions & answers sessions. You may withdraw your consent by cancelling your registration (following the cancel link at the bottom of your registration confirmation email) or sending an email to This email address is being protected from spambots. You need JavaScript enabled to view it.. Please note that you will not be allowed to take part in the talks if you withdraw your consent before they start and that after the recording has been published, we cannot remove it from YouTube. Click here to learn more about ZMT's privacy policy for online seminars.


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