DiDEM latest news
Dr. Samuel Razanaka presenting his work at the DIDEM thematic school in Mahajanga, September 2023 @Xavier Koenig
Long time series (more than a century) are difficult to construct but they are useful for understanding hydro-geomorphological phenomena that take place over the long term and anticipating future risks.
The Betsiboka River into which the Ikopa flows from Antananarivo, capital of Madagascar, is characterized by hyper-sedimentation which gives it a red color. Downstream, at Mahajanga, the river forms a delta nested in its estuary and influenced by the tides, which becomes blocked over the years, then flows into Bombetoka Bay and the Mozambique Channel. This clogging takes the form of islets which are colonized by the mangrove, once emerged. Monitoring a population of islets and their cover by mangroves makes it possible to evaluate the sedimentation speed of the delta and the dynamics of the mangroves (colonization, growth, mortality).
These data - and the associated article - illustrate the stages of constructing a map representing all of these islets, located and numbered in 2021 (Satellite Sentinel 2 image of 04/28/21, low tide = -1.86) , the delimitation of the nested delta, the location of the islets according to an upstream-downstream gradient, finally the contours and numbering of each islet. This inventory can thus serve as a reference, as an end point for historical studies, or as a starting point for multi-year monitoring enabled by the Sentinel 2 satellite.
At the end of the WIODER (Western Indian Ocean Deltas Exchange and Research network) project, the CRGIZC (Centre Régional de Gestion Intégrée des Zones Côtières), now CER (Comité Environnemental Régional), of the Boeny region had formulated two questions to IRD-CNRE scientists about the Betsiboka river, These questions were progressively reformulated and addressed by students before and after COVID, and discussed in DIDEM workshops N°3 and N°4 of the Dialogues science-decision making (2022).
Taking into account the recommendations of these Dialogues, more explicit maps for decision-makers were finalized in 2024 by Michel Raherimanantsoa for the upstream Betsiboka delta, considering the Betsiboka watershed from Maevatanana, i.e. from the junction with the Ikopa, to Mahajanga. These maps illustrate the answers given to the two questions posed:
- How can we anticipate the area available for cultivation during flood recession in Ambatoboeny, which is apparently highly variable from one year to the next?
- How can the silting-up of the Marovoay rice fields be prevented?
As waterbird biomass, and in particular the piscivores, can be considered a proxy for fish and crustacean production these correlate with human well-being as fisheries are an important livelihood component in the delta, Maputo Bay and adjacent coastal waters. Maintaining such floodpeaks is thus essential for maintaining and enhancing the livelihoods of the vulnerable users of the area. In addition, it is suggested that managed flood releases prior to the equinox tides of September would be beneficial to both biodiversity values and ecosystem services of the delta, including by preventing high salinities destroying floodplain vegetation and thus increasing the risk of erosion.
Deltas are productive and biodiversity rich ecosystems but also vulnerable to sea-level rise and human alterations of river hydrology. In order to study the dynamics of the Tana River delta in Kenya, we implemented a multi-disciplinary approach: Sediment coring, geochemical analysis, pollen and macrofossils, geomorphological studies came in support of the understanding of the landscape dynamics.
Our results indicate that since the mid Holocene (5500 BP), the delta has evolved from a mangrove ecosystem to the current woody floodplain, as a response to sea level fluctuation, hydrological changes and human alterations. Over the past two centuries, the Tana River has changed its course 3 times. We highlight the increasing vulnerability of the Tana River delta under present sea level rise and continued upstream river alteration. We suggest that management of the delta should take into account the dynamic nature of the landscape and adopt climate change adaptation measures co-constructed between local population, scientists and decision-makers.
The defenses of the first class of the Master II in “Gestion des Ressources Environnementales et Développement Durable” (GRE2D) took place from September 16 to 19, 2024 at the Centre Universitaire de Patsy. The DIDEM-Comores team, comprising Gilbert David and Nourddine Mirhani, took part in the jury as a partner of the program.
September 2024
Nourddine Mirhani, coordinator of DIDEM's activities in the Comoros and editor of the Atlas of Coastal Landscapes at Risk in Anjouan and Mohéli, presented his work at the Patsy University Campus in Anjouan.
Designed as a multi-purpose tool, the atlas can be used for information, awareness-raising, education, scientific research, decision-making and coastal management. Richly illustrated with photographs, graphs, maps and tables, it provides an in-depth and immediate visual understanding of the issues and proposed solutions.
September 2024
France metropole
Theater: “Reef”, puppets and the environment
Immerse yourself in the world of coral reefs in this immersive theater show, combining environmental protection and education for young and old alike.
An initiative of the Institut Régional de Développement, this creation by Théâtre des Alberts plunges you into the beauty and complexity of coral reefs, a living, delicate and inspiring world. Three actors and a puppet explore this fascinating microcosm and share its workings, blending poetry, knowledge and reflection on society. RÉCIF is the fruit of a collective exploration combining art and science. The show is a veritable ode to nature, questioning our relationship with the environment: isn't it urgent to marvel, but also to worry about the future of the reefs?
October 2 to 3, 2024, Théâtre des Alberts, Paris
From Monday June 10 to Friday June 14, a thematic school on the vulnerability of reef heritage was held at the University of Seychelles, Anse Royale campus. Some thirty participants from a variety of backgrounds and disciplines shared their experiences from several countries in the Western Indian Ocean and Europe: Comoros, France, Kenya, Madagascar, Mauritius, Monaco, Seychelles and Tanzania.
> Go to the school page: concept, presentations and photos
June 2024
Global DIDEM
"Empowering Southwest Indian Ocean Communities for Science-Based Coastal Conservation: IRD and its partnership in action" 2024 Ocean Decade Conference, Barcelona
Pascale Chabanet presented the DIDEM project at the Ocean Decade 2024 Conference on Friday April 12 in Barcelona.
Three years into the United Nations Decade of Oceanography for Sustainable Development (2021-2030), this global conference brought together the Ocean Decade community and its partners to celebrate achievements and define common priorities for the future of the Decade.
April 2024
Benjamin Tsirilaza defended his thesis on March 25, 2024 at the University of Toliara, Madagascar. Title : Bio-ecology and fish exploitation in the Betsiboka Estuary, northwest Madagascar
> Access the abstract and the presentation
March 2024
On December 11, 2023 at 2pm, Uacitissa Mandamule will present her thesis entitled "When the elements rage: Displacement and resettlement of populations affected by Cyclone Idai and flooding in Búzi (Mozambique)". The defense will take place at the Laboratoire Population Environnement Développement, at Aix-Marseille University, with a jury comprising Sandrine Revet, Jacques Véron, Michel Cahen, Stéphanie Duvail and Valérie Golaz.
If you wish to attend in person, please let us know before 06/12 to obtain access to the campus (stephanie.duvail@ird.fr). A zoom link is provided for those who would like to attend remotely.
#PhDdefense #Mozambique
December 2023
Delegations from the Seychelles, Reunion and Comoros joined the PAREO MAURITIUS team in good spirits this week, for the two restitutions of the project to be held on November 14 (restitution to Officials and Media) and 15 (restitution open to the public)!
On the program: a visit to the marsh and mangrove swamp at Anse-la-raie with the NGO Reef Conservation, and a boat trip with a launch in the Mahébourg lagoon to Île au Fouquet and Trou Moutou!
Join us for the official and media presentation: we'll be LIVE tomorrow, November 14, 2023, from the Plaza in Rose-hill between 9am and 12pm on the PAREO facebook page!
#CoralReefs #ChildrenAreInvolved
PAREO Facebook to follow the day live
November 2023
An international team of scientists sets out to study the impact of climate change on the ecosystems of the Indian Ocean, in an attempt to understand the future of the planet.
The documentary on Monaco Explorations' Indian Ocean Expedition is available online until January 4, 2024, on the Arte.tv channel.
For those unable to access Arte, other versions are available online:
- a short English/French version: https://www.youtube.com/watch?v=L8mzPygDwUs
- a longer German/English version: https://www.youtube.com/watch?v=JRVodW7Vj54
#IndianOceanExpedition #MonacoExplorations
> Read more about this expedition
November 2023
Nourddine Mirhani and Gilbert David, the two scientists in charge of DIDEM's islands and archipelagos project, taught the first courses of the second year of the Master's program in Natural Resource Management and Sustainable Development at the University of the Comoros' Centre de Patsy.
#ComorosUniversity #PatsyCenter
October 2023
Researchers from Eduardo Mondlane University, managers from the District and the Ministry of the Environment, and resource persons representing local communities attended a workshop to present the results of the Eflows project, co-funded by the DIDEM and WIOSAP projects.
#EFlows #Deltas
September 2023
Faced with the destruction of biodiversity, it is becoming urgent to make political and management decision-makers, as well as the general public, aware of the value of nature and the costs that its destruction entails.
Is it enough to talk in terms of "natural capital"? Or should we be more precise, and detail the "ecosystem services" that this natural capital renders to human populations?
For 6 days, 30 scientists, decision-makers and protected area managers took part in the DIDEM thematic school. Classroom and field sessions marked a week rich in exchange and learning.
#EnvironmentalAccounting #EcosystemServices
> Know more about the school and read the content
September 2023
The DIDEM/Deltas Madagascar team (CNRE, IRD) was honored to be received by the Governor of the Boeny Region, Madagascar, on September 12, 2023.
It was an opportunity to present the research work carried out by the team on the Betsiboka river and delta, via WIODER and DIDEM and to discuss the new project currently being set up with the Boeny CER, Regional Environmental Directorate, the coastal protected areas and the scientists involved in previous dialogue between science and decision makers.
#DeltaBetsiboka #Newproject
> A look back at the meeting in pictures
September 2023
Benjamin Tsirilaza, DIDEM PhD student, presented his work at the PAFFA conference in Brazzaville, Congo, September 18-22, 2023.
#Madagascar #Traditionalfisheries
Access full abstract and presentation here
September 2023
Kenya
Poster : 5500 years of ecosystem change in the Tana River Delta (Kenya) in response to sea-level fluctuation, hydrological dynamics and human impacts. By Peter N. Gitau at the INQUA Roma conference
Coastal deltas worldwide are under risk of degradation due to the increasing impacts of sea-level rise and alterations of river hydrology.
This double threat also applies to the Tana River Delta in Kenya, which forms a lifeline for local communities almost entirely dependent on its ecosystem services, while also providing very attractive habitat to a wide variety of flora and fauna that make this area a biodiversity hotspot in the Eastern African coastal region1.
However, past and historical dynamics that have influenced the current status of the Tana River Delta ecosystem are not sufficiently understood to construct a proper baseline to evaluate the uniqueness and magnitude of the delta’s current environmental challenges.
July 2023
The second LittoSIM Majunga workshop took place in the large hall of the Hotel 401 Majunga from July 11 to 13.
The participants were all technicians with different specialities, but working on the theme of marine or rainfall submersion. The "Majunga" archetype of the LittoSIM tool and the data, including recently acquired data used in this archetype, were presented to the technicians from the city of Majunga.
#SeriousGame #MarineSubmersion
July 2023
Kenya - video
Knowledge Sharing Workshop on Impacts of Sea Water Intrusion at Kalota, Tana River Delta
The workshop was held on June 17th 2023 at Semikaro Primary School. It allowed scientists, community leaders and community members to share knowledge and to jointly analyse the environmental changes observed in the Kalota section of the Tana River Delta.
It was organised by the DiDEM Project-Kenya, facilitated by the team from the National Museums of Kenya (NMK), French Institute of Research for Development (IRD) and the Kenya Wetlands Biodiversity Research Team (KENWEB).
Filmmaker Khamis Ramadhan was able to gather testimonials from workshop participants. Three videos are available:
- a short english version (3 mins)
- a long english version (13 mins)
- a long swahili version (13 mins)
July 2023
The second SWOT mission to Madagascar took place in April 2023. This 2023 mission was designed to test the SWOT satellite in its short 3-month phase of daily data production, from March to June 2023.
#SWOT satellite #WIODERandDIDEMteam
July 2023
A total of 6 Dialogue Sciences-Décideurs workshops have been held in the Boeny region since 2021.
- Dialogues 1 and 2 focused on the Bombetoka mangrove and on mangroves in coastal protected areas.
- Dialogues 3 and 4 focused on the Ambatoboeny flooding and the silting-up of rice-growing areas in Marovoay.
- Dialogues 5 and 6 focused on flood scenarios in the city of Mahajanga and Dialogue with stakeholders in the Betsiboka delta.
#Dialogue Science Civil Society #dialogue science decision makers #Madagascar
July 2023
The recently created scientific network on Western Indian Ocean National Or International SEamounts, banks, submarine structures (WIO N.O.I.S.E.) held its first Workshop “Multidisciplinary Scientific Approaches to Support Marine Regional Governance in the Western Indian Ocean” in Mauritius from 3 to 5 May 2023. The workshop was hosted by the Department for Continental Shelf, Maritime Zones Administration and Exploration (CSMZAE) of the Prime Minister's Office and by the University of Mauritius (UOM).
June 2023
High Sea
To Explain the relationship between the natural sciences and public decision-making in the governance of marine areas, recalling the provisions of the International Law of the Sea
The 3 training materials that took place on board the S.A. Agulhas II during the Indian Ocean Expedition are now available online:
- Training 1“Basic concepts and divisions of ocean areas" General aspects/ Indian Ocean aspects” (DOI : 10.5281/zenodo.7705826), Auteur : Florence Galletti
- Training 2 - "Remote Marine Environmental Heritage” How to address this crosscutting and emerging issue of biodiversity governance? (DOI : 10.5281/zenodo.8029879), Auteur : Florence Galletti
- Training 3 - "MARINE SCIENTIFIC RESEARCH & LAW OF THE SEA" Discussion upon some modern interactions and difficulties (DOI: 10.5281/zenodo.8039805), Auteur : Florence Galletti
June 2023
Madagascar
Photo exhibition : Images for a dialogue
This photographic exhibition showcases Rijasolo's reportage following the DIDEM-Deltas-Madagascar scientific team along the Betsiboka river and delta in September 2022.
From field measurements and participatory observatory management to science-decision-maker-civil society dialogue workshops, the report covers every facet of the multidisciplinary scientific missions and highlights the environmental and social challenges of the Betsiboka delta.
The exhibition was inaugurated at the Musée de la Photographie in Antananarivo on May 5, 2023, then at the Alliance Française in Mahajanga on May 12, 2023, and presented for one month.
#Betsiboka #DiDEMresearch #Rijasolo
> Discover the full exhibition here
May 2023
On the program
2pm-4pm: reef games led by project students
4pm-6pm: official opening, presentation of the project, Boléro children's show and prize-giving ceremony
The event is available on the PAREO project FB page: https://www.facebook.com/PareoProject
May 2023
Children from Ndrondroni elementary public school visited the islet of Wenefou, Moheli National Park, for the second time, to observe the coral reef.
4 workshops were offered:
- playing the Polypeï goose board game
- choosing the site for the Marine Educational Area
- learning about the importance of certain underwater species
- snorkeling to observe the reef and its inhabitants.
May 2023
Integrate scientific knowledge into decision-making
for coastal and marine management
in the Western Indian Ocean
2021-2024
Mohéli, Comores @Nourddine Mirhani