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Les articles d'Anis GuelmamiMovement ecology of post-breeding gulls reveals wetland connectivity in northwestern Africa
de Víctor Martín-Vélez, Haytem Bouchri, Anis Guelmami, Ursula Hofle, Joan Navarro, María J. Navarro-Ramos, Andy J. Green
In Global Ecology and Conservation, 71 (November, 2026), e04454
En ligne : www.sciencedirect.com[...]
Wetlands are among the most threatened ecosystems worldwide, and their loss increasingly compromises landscape connectivity essential for persistence of waterbird populations. In the Mediterranean region, and particularly in northwestern Africa, conservation prioritisation has largely focused on sites supporting high bird numbers, while the role of wetlands in maintaining functional connectivity remains poorly understood. Here, we quantify wetland connectivity in Morocco using the black-headed gull (Chroicocephalus ridibundus) as a model migratory waterbird. We obtained high-resolution GPS tracking for 64 individuals breeding in south-western Iberia. We combined the tracks of the 19 individuals that moved to Morocco with network analyses, to identify key sites and habitat types that contribute to spatial connectivity. Tracked gulls relied on a heterogeneous network of 26 wetlands, including rivers, dams, lagoons and temporary wetlands. They also used anthropogenic habitats such as landfills and wastewater treatment plants. Network analyses revealed a sparsely connected but spatially structured system, with connectivity concentrated in three main geographical regions. Several unprotected wetlands, particularly rivers and reservoirs, showed high betweenness values revealing their importance for maintaining network integrity, comparable to those of existing Ramsar sites. Removal simulations highlighted the vulnerability of connectivity to the loss of a small number of key sites (nodes) in the wetland network. Furthermore, GPS data show that Moroccan wetlands are more important for black-headed gulls from July to September than expected from eBird data. Our results demonstrate how incorporating movement-based connectivity metrics can improve wetland conservation planning. Protecting functionally important wetlands is critical to safeguard waterbird connectivity, and hence ecosystem resilience, in northwestern Africa.
de Miguel Cabrera-Brufau, Camille Minaudo, Katrin Attermeyer, Alba Camacho-Santamans, Rafael Carballeira, Benjamin Misteli, Jorge Montes-Pérez, Daniel Morant, Biel Obrador, Antonio Picazo, et al.
In Ecological Engineering, 232 (November, 2026), 108080
En ligne : www.sciencedirect.com[...]
Coastal wetlands play a substantial role in regulating Earth's climate through exchanges of greenhouse gases (GHGs). Current European policies promote widespread coastal wetland restoration to reverse historical losses and ongoing pressures. However, substantial uncertainty remains regarding how carbon dioxide (CO2) and methane (CH4) fluxes respond to restoration across different coastal wetland types and whether these responses translate into net climate mitigation in terms of CO2 equivalents (CO2-eq). We measured simultaneous CO2 and CH4 fluxes using static chambers across four seasons at multiple locations spanning preserved, altered and restored sites within six European coastal wetlands of different ecological types. By comparing GHG exchanges and resulting CO2-eq balances across wetlands, we identified dominant biogeochemical drivers of CO2 and CH4 dynamics and assessed the climate mitigation potential of conservation and restoration actions. CO2 fluxes were primarily controlled by landscape-scale vegetation cover and inundation, whereas CH4 emissions responded to less evident changes in water quality, salinity and wetland hydrodynamics. Comparisons of CO2-eq balances between altered and restored sites showed that seagrass replantation was associated with significant mitigation potential under both 100-year and 20-year CH4 warming scenarios, while eutrophication reversal through improved water treatment was only significant under the 20-year scenario. In contrast, other restoration measures modified CO2 and CH4 fluxes in opposing directions, resulting in no significant net change in combined CO2-eq balances. Overall, our results demonstrate that climatic responses to coastal wetland restoration are both GHG-specific and wetland-type dependent, underscoring the need for tailored restoration strategies and robust, multi-GHG monitoring to detect and accurately quantify potential climatic benefits.
de Bruna R. F. Oliveira, Antonio Camacho, Anis Guelmami, Christoph Schröder, Nina Bègue, Martynas Bucas, Constantin Cazacu, Elisa Ciravegna, João Pedro Coelho, Relu Giuca Constantin, et al.
In Environmental Science & Policy, 179 (May, 2026), 104386
En ligne : www.sciencedirect.com[...]
Ecosystem restoration is a paramount policy priority for this decade, with ambitious global and European targets requiring unprecedented levels of data-driven implementation. Achieving effective and equitable restoration, particularly for coastal wetlands, hinges on spatially explicit socio-ecological information - maps that integrate habitats, ecosystem services, human activities, and pressures to guide prioritization, stakeholder negotiation, and adaptive management. This study, grounded in the RESTORE4Cs initiative, introduces an innovative multi-layered dataset that bridges science and policy for six emblematic European coastal wetlands: Ria de Aveiro (Portugal), Valencian Wetlands (Spain), Camargue (France), Southwest Dutch Delta (Netherlands), Curonian Lagoon (Lithuania), and the Danube Delta (Romania). The dataset consolidates ecological mapping (EUNIS 2021, 2022), human activity and pressure documentation (aligned with EU Habitats Directive, Water Framework Directive, Marine Strategy Framework Directive), comprehensive ecosystem services mapping (CICES v5.1), alongside robust participatory community and stakeholder data. Altogether, the database encapsulates 97 habitat records, 23,160 activity-pressure associations, and 1,668 ecosystem service records—enabling robust cross-regional analyses and direct integration into evidence-based decision support tools. By illustrating practical pathways for participatory engagement, trade-off negotiation, and cross-scale integration, this research equips scientists, policymakers, practitioners, and communities with the scientific foundation to propel the Nature Restoration Regulation and Biodiversity Strategy 2030 objectives, fortifying Europe’s climate adaptation trajectory. The approach showcased signals a new era for restoration science – where spatially explicit, multi-actor data supports policy, mobilizes citizen stewardship, and accelerates the transformative ambitions of Europe’s restoration decade.A framework for selecting Nature-based Solutions: applications and challenges at the catchment scale
de Awais Naeem Sarwar, Cristina Caramiello, Francesco Pugliese, Seifeddine Jomaa, Anis Guelmami, Michaël Ronse, Pier Paolo Roggero, Nunzio Marrone, Francesco De Paola, Irem Daloglu Cetinkaya, et al.
In Journal of Environmental Management, 394 (November, 2025), 127220
En ligne : www.sciencedirect.com[...]
Nature-based Solutions (NbS) aim to address natural and anthropogenic risks, enhancing ecosystem-based approaches, biodiversity, human health, and socio-economic growth. Despite the growing interest in NbS applications, their integration into landscape planning at the catchment scale remains limited, given the multi-disciplinary comprehensive features related to them. To overcome this shortcoming, this study presents a multi-disciplinary GIS-based framework for identifying, selecting, and prioritizing NbS at the catchment scale, specifically focusing on water resources availability and management. The catchment is first categorized through a multi-level approach that considers the ecosystem types, climate class, and geomorphological characteristics (Stage 1). Through a literature review, an NbS catalog (Decision Matrix) was built, considering catchment classification (Stage 2). Finally, potential solutions from the decision matrix were mapped for each class (Stage 3). Stakeholder engagement was conceptualized by integrating the technical outcomes with the local perspectives to enhance the co-design and knowledge-sharing in the decision process. The framework was tested in the Bode River catchment (Germany), showing reliable results in detecting the potential areas for NbS implementation, and the framework's replicability to multiple contexts, given its ease of application and tailorable structure, even when different policy makers are involved in the process. The proposed framework supports baseline NbS map development to identify priority areas, engage stakeholders, and guide investments in alignment with long-term regional goals and the Sustainable Development Goals (SDGs).
de Dilara Arslan, Elie Gaget, Kerim Cicek, Anthony Olivier, Thomas Galewski, Ömer Döndüren, Anis Guelmami, Lisa Ernoul, Arnaud Béchet
In BMC Ecology and Evolution, 25(1) (June, 2025), 58
En ligne : doi.org[...]
Wetlands have been some of the most destroyed ecosystems over the last century, with important land-use changes resulting from agricultural, industrial, and urban development. Gediz Delta is a large wetland on the Aegean coast of Western Türkiye with natural areas affected by conversion to agriculture and urban developments from the Izmir metropolis. We assessed the effects of landscape type (natural, agricultural, and urban) on the composition of breeding bird (90 species) and reptile (14 species) communities in the Gediz Delta between 2019 and 2021. We used generalized linear models to estimate the effect of landscape types on community indexes and joint species distribution models to assess how species-specific habitat preferences explained their responses to landscape type.Large-scale loss of Mediterranean coastal marshes under rising sea levels by 2100
de Mark Schuerch, Joshua Kiesel, Olivier Boutron, Anis Guelmami, Claudia Wolff, Wolfgang Cramer, Nuno Caiola, Carles Ibáñez, Athanasios T. Vafeidis
In Communications Earth & Environment, 6(1) (February, 2025), 1-13
En ligne : www.nature.com[...]
Mediterranean coastal wetlands account for important biodiversity and ecosystem services. But climate-change induced sea-level rise poses a critical risk to their survival. Here, we assess these risks for Mediterranean coastal marshes, one key type of Mediterranean coastal wetlands, and identify main drivers for future coastal marsh change for the Mediterranean and comparable coastlines. We apply an integrated modelling approach that accounts for future sea-level rise, sediment accretion, coastal management and marsh inland migration processes. Depending on climate mitigation scenarios, widespread coastal marsh loss is projected, ranging from 8% to 92% of current extents. For Egypt, France, and Algeria, we predict (near) total loss of coastal marshes by 2100 for current coastal management and sediment supply scenarios. Overall, losses could at least be halved if additional inland migration space were created, e.g. through passive or active habitat restoration. Bold climate mitigation and local adaptation are needed to preserve existing coastal marshes.Exposure of wetlands important for nonbreeding waterbirds to sea-level rise in the Mediterranean
de Fabien Verniest, Thomas Galewski, Olivier Boutron, Laura Dami, Pierre Defos du Rau, Anis Guelmami, Romain Julliard, Nadège Popoff, Marie Suet, Loic Willm, et al.
In Conservation Biology, 2024 (May, 2024), e14288
En ligne : onlinelibrary.wiley.com[...]
Sea-level rise (SLR) is expected to cause major changes to coastal wetlands, which are among the world's most vulnerable ecosystems and are critical for nonbreeding waterbirds. Because strategies for adaptation to SLR, such as nature-based solutions and designation of protected areas, can locally reduce the negative effects of coastal flooding under SLR on coastal wetlands, it is crucial to prioritize adaptation efforts, especially for wetlands of international importance for biodiversity. We assessed the exposure of coastal wetlands important for nonbreeding waterbirds to projected SLR along the Mediterranean coasts of 8 countries by modeling future coastal flooding under 7 scenarios of SLR by 2100 (from 44- to 161-cm rise) with a static inundation approach. Exposure to coastal flooding under future SLR was assessed for 938 Mediterranean coastal sites (≤30 km from the coastline) where 145 species of nonbreeding birds were monitored as part of the International Waterbird Census and for which the monitoring area was delineated by a polygon (64.3% of the coastal sites monitored in the Mediterranean region). Thirty-four percent of sites were threatened by future SLR, even under the most optimistic scenarios. Protected study sites and study sites of international importance for waterbirds were, respectively, 1.5 and 2 times more exposed to SLR than the other sites under the most optimistic scenario. Accordingly, we advocate for the development of a prioritization scheme to be applied to these wetlands for the implementation of strategies for adaptation to SLR to anticipate the effects of coastal flooding. Our study provides major guidance for conservation planning under global change in several countries of the Mediterranean region.
de Imene Benzina, Abdelkrim Si Bachir, Abdelkrim Arar, Anis Guelmami, Christian Perennou
In Present environment and sustainable development, 18(1) (2024)
En ligne : www.pesd.ro[...]
Wetlands are present within intricate ecological settings, exhibiting dynamic changes over time and across different areas with regard to their functional and structural diversity. Several approaches have been introduced for ecosystem analysis and management since 1990s, where Driver – Pressure – State – Impact – Response (DPSIR) framework is one of the widely used approaches for assessing and managing environmental problems. In this study, we proposed a DPSIR framework as a model in the Sebkhates of Aures wetland complex (SAWC, Northeast of Algeria), in order to create a regional wetland observatory to deliver ecosystem services within current state of changes resulted from socioeconomic drivers. DPSIR facilitates the identification of essential indicators to detect threats to the Sebkahtes of Aures wetlands complex (SAWC), influencing policymakers to enhance the protection and management of these wetlands. In line with the established DPSIR framework. This same approach and methodology could be applied to the other 15 wetlands complexes known in Algeria, culminating in the creation of a national wetland observatory. Furthermore, DPSIR can be employed as an analytical tool for policy making in the context of sustainable management of wetland ecosystems and can serve as a model in the establishment and development of various observatory programs in Algeria.
de Anis Guelmami
In Euro-Mediterranean Journal for Environmental Integration, December (December, 2023)
En ligne : link.springer.com[...]
Les zones humides méditerranéennes sont les écosystèmes les plus riches et les plus productifs de la région et sont essentielles pour l'adaptation au changement climatique et l'atténuation de ses effets. Cependant, malgré leur importance, elles ont subi une destruction importante au fil du temps. On estime qu’environ la moitié des zones humides naturelles ont disparu depuis les années 1970, et la tendance régionale ne montre aucun signe de ralentissement. Il est donc urgent de mettre en œuvre des solutions concrètes pour préserver les zones humides restantes et restaurer celles qui ont disparu. La disponibilité croissante de données d'Observation de la Terre (OT) libres et gratuits a permis de cartographier ces écosystèmes et de suivre leur état et leurs tendances. Dans cet article, nous démontrons comment ces outils peuvent aider à la pré-identification des sites candidats pour la restauration des zones humides à grande échelle, à travers la cartographie et la délimitation des habitats humides existants et perdus, leur usage actuel et l'estimation des efforts nécessaires pour recréer ceux ayant été perdus et transformés. L’approche a été testée dans le bassin versant du Sebou, au Maroc, ainsi que celui de la Medjerda, transfrontalier entre l'Algérie et la Tunisie. Les produits cartographiques obtenus ont permis d'identifier une superficie de zones humides perdues potentiellement restaurables de plus de 7000 km² et 1700 km², dans les deux bassins respectivement. Ces résultats présentent une grande valeur pour la gestion des ressources en eau et l'aménagement du territoire car ils peuvent améliorer et aider les efforts de priorisation pour la restauration des zones humides aux échelles locales, nationales et régionale. Ils peuvent servir de données de base pour identifier les sites candidats à la mise en œuvre d'actions de restauration des zones humides en tant que Solutions fondées sur la Nature, régénérer leurs habitats et réhabiliter les services écosystémiques qu'elles fournissent à la société.
de Fabien Verniest, Isabelle Le Viol, Romain Julliard, Laura Dami, Anis Guelmami, Marie Suet, Wed Abdou, Hichem Azafzaf, Nadjiba Bendjedda, Taulant Bino, et al.
In Biological Conservation, 279 (March, 2023), 10
En ligne : www.sciencedirect.com[...]
Thermal adjustment of waterbird communities to climate warming is crucial but hampered by natural habitat conversion, increasing their climatic debt. As it is, in contrast, facilitated in protected areas, assessing the adequacy of the current protected areas network with respect to future climate and land-use changes and identifying priority sites to protect is of major importance. In this study, we assess the thermal adjustment limitations that non-breeding waterbird communities might experience by the end of the 21st century in the Mediterranean region to highlight priorities for wetland protection. Priorities were set by combining the exposure of waterbird communities to natural habitat conversion and climate warming with their thermal specialization. The latter was calculated using winter abundance data of 151 species from 2932 sites of the International Waterbird Census in 21 Mediterranean countries. Exposure was assessed using future projections of temperature and land-use under four CMIP6 scenarios (SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5). We found that strictly protected areas are located in wetlands whose waterbird communities, without protection, would likely experience high limitations in thermal adjustment in the coming decades. This highlights that the location of existing protected areas may effectively support the thermal adjustment of waterbird communities to future climate warming. However, 490 sites considered at risk lack protection, including 32 sites of international importance for waterbirds, stressing the need to strengthen the protected areas network in these sites in priority. Our study provides important guidance for conservation planning in the Mediterranean region to support waterbird responses to climate change. /
Dans notre étude, nous avons évalué les difficultés potentielles des communautés d’oiseaux d’eau hivernants à ajuster leur composition aux futurs changements de température en combinant la spécialisation thermique de la communauté avec deux métriques d’exposition à l’augmentation future des températures hivernales et à la perte future d’habitats naturels à l’horizon 2090 selon quatre scénarios futurs différents. Nous avons ainsi constaté que les aires protégées, et notamment celles strictement protégées, sont situées dans des zones humides dont les communautés d'oiseaux d'eau, sans protection, auraient probablement connu de fortes difficultés d'ajustement thermique au cours des prochaines décennies. Cela met en évidence la pertinence de l'emplacement des aires protégées existantes qui pourront faciliter de manière efficace l'adaptation thermique des communautés d'oiseaux d'eau au réchauffement climatique futur. Cependant, nous avons également identifié 490 sites à risque et ne bénéficiant d'aucun statut de protection, dont 32 sites d'importance internationale pour les oiseaux d'eau, ce qui souligne la nécessité de renforcer le réseau d'aires protégées méditerranéen dans ces sites en priorité.
de Sébastien Rapinel, Léa Panhelleux, Guillaume Gayet, Rachel Vanacker, Blandine Lemercier, Bertrand Laroche, François Chambaud, Anis Guelmami, Laurence Hubert-Moy
In Heliyon, 9(2) (February, 2023), 17
En ligne : www.cell.com[...]
While wetland ecosystem services are widely recognized, the lack of fine-scale national inventories prevents successful implementation of conservation policies. Wetlands are difficult to map due to their complex fine-grained spatial pattern and fuzzy boundaries. However, the increasing amount of open high-spatial-resolution remote sensing data and accurately georeferenced field data archives, as well as progress in artificial intelligence (AI), provide opportunities for fine-scale national wetland mapping. The objective of this study was to map wetlands over mainland France (ca. 550,000 km2) by applying AI to environmental variables derived from remote sensing and archive field data. A random forest model was calibrated using spatial cross-validation according to the precision-recall area under the curve (PR-AUC) index using ca. 135,000 soil or flora plots from archive databases, as well as 5 m topographical variables derived from an airborne DTM and a geological map. The model was validated using an experimentally designed sampling strategy with ca. 3000 plots collected during a ground survey in 2021 along non-wetland/wetland transects. Map accuracy was then compared to those of nine existing wetland maps with global, European, or national coverage. The model-derived suitability map (PR-AUC 0.76) highlights the gradual boundaries and fine-grained pattern of wetlands. The binary map is significantly more accurate (F1-score 0.75, overall accuracy 0.67) than existing wetland maps. The approach and end-results are of important value for spatial planning and environmental management since the high-resolution suitability and binary maps enable more targeted conservation measures to support biodiversity conservation, water resources maintenance, and carbon storage.
de Mauro Fois, Alba Cuena Lombraña, N Araç, M Artufel, E Atak, V Attard, Gianluigi Bacchetta, Salvatore Cambria, K Charfi, D Dizdaroğlu, et al.
In Flora Mediterranea, 32 (12/2022), 339-349
En ligne : www.herbmedit.org[...]
MedIsWet (Conservation of the island wetlands of the Mediterranean Basin) is a MAVA funded project which aims at investigating all seasonal or permanent island wetlands both natural and artificial, with a minimum extent of 0.1 hectares. More than 16,000 wetlands from almost all the Mediterranean, including islands from France, Italy, Malta, Croatia, Cyprus, Tunisia, Turkey, Greece and Spain were mapped. Over 2,500 of them were inventoried in the field and more than 500 scientific contributions catalogued. In total, more than 35,000 plant occurrences were uploaded, in a standardised and comparable way, on the national open-source web portals. These can be related to the recorded threats, uses and other spatially retrievable information. Here, we show strengths and shortfalls of the already available information about the floristic records. Although further improvements are needed, we discuss how these data can be used for research and policy actions and to develop conservation projects.
Key words: databases, floristic records, field surveys, rapid assessment, hydro-hygrophilous vegetation.
de Fabien Verniest, Thomas Galewski, Romain Julliard, Anis Guelmami, Isabelle Le Viol
In Conservation Science and Practice, Online (October, 2022), 17
En ligne : onlinelibrary.wiley.com[...]
Identifying sites that are both important for biodiversity and likely to be heavily affected by anthropogenic pressures in the future is crucial to settle priorities in the implementation of conservation measures, such as the designation of new protected areas. Although assessing the exposure of terrestrial Key Biodiversity Areas to global change would support such identification, it has never been performed to our knowledge. In addition, previous exposure assessments have been limited to few metrics of climate change and have not considered other global change components. Here, we assess the extent to which terrestrial (including inland water) Key Biodiversity Areas are exposed to future climate change and land-use modifications in 29 countries of the Mediterranean region, and identify countries where additional protection efforts are most needed. To this end, we calculated two local and two regional exposure metrics using projections of climate and land-use for late 21st century under four scenarios that were used in the sixth assessment report of the Intergovernmental Panel on Climate Change (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). These four exposure metrics were subsequently combined into an exposure index ranking sites from least to most exposed to climate and land-use changes. We highlight that the most exposed non-protected Key Biodiversity Areas are located in countries where the protection of this network is lowest (i.e., high number and percentage of non-protected sites). We also found that Key Biodiversity Areas were overall more exposed than the rest of the study zone and that the sites most in need of conservation actions were similar across future scenarios. Our study reinforces the pressing necessity to strengthen and extend conservation measures in Mediterranean Key Biodiversity Areas, especially in Middle-East and Maghreb countries whose Key Biodiversity Areas are both at risk to be strongly affected by anthropogenic pressures and insufficiently protected.
de Stefano Barchiesi, Antonio Camacho, Eva Hernández, Anis Guelmami, Flavio Monti, Alessio Satta, Osvaldo Jordán, Christine Angelini
In Wetlands, 42(5) (June, 2022), 46
En ligne : link.springer.com[...]
Although environmental flow regime assessments are becoming increasingly holistic, they rarely provoke water managers to enact the adaptive water reallocation mechanisms required to secure environmental water for wetlands. The conditions that cause science-based environmental flow assessments to succeed or fail in informing the management of environmental water requirements remain unclear. To begin to resolve these conditions, we used process tracing to deconstruct the sequence of activities required to manage environmental water in four case studies of seasonally ponding wetlands in Mediterranean and Mesoamerican watersheds. We hypothesized that, when the flexibility and equitability of the socioeconomic system do not match the complexity of the biophysical system, this leads to a failure of managers to integrate scientific guidance in their allocation of environmental water. Diagnostic evidence gathered indicates that science-management partnerships are essential to align institutional flexibility and socioeconomic equitability with the system’s ecohydrological complexity, and thus move from determination to reallocation of environmental water. These results confirm that institutions e.g., river basin organizations need to be supplemented by motivated actors with experience and skill to negotiate allocation and adaptive management of environmental water. These institutional-actor synergies are likely to be especially important in water scarce regions when the need to accommodate extreme hydrological conditions is not met by national governance capacity. We conclude by focusing on benefit sharing as a means to better describe the conditions for successful science-based environmental flow assessments that realize productive efficiency in environmental water allocation i.e., recognition of multiple values for both people and ecosystems.
de Nadège Popoff, Elie Gaget, Arnaud Béchet, Laura Dami, Pierre Defos Du Rau, Ilse Geijzendorffer, Anis Guelmami, Jean-Yves Mondain-Monval, Christian Perennou, Marie Suet, et al.
In Biodiversity and conservation, 30 (July, 2021), 19
En ligne : link.springer.com[...]
The Mediterranean Basin is a biodiversity hotspot. Wetlands make a key contribution to this status, but many of them remain outside the Ramsar network fifty years after the establishment of the Ramsar Convention. Here we evaluate the extent to which the Mediterranean Ramsar network covers wetlands of international importance for wintering waterbirds using the Ramsar Convention criteria 2 (species of conservation concern), 5 (> 20,000 waterbirds) and 6 (1% of a population). These criteria were applied to 4186 sites in 24 Mediterranean countries using counts of 145 wintering waterbird species from 1991 to 2017. We identified 161 sites of international importance for waterbirds that have not yet been declared as Ramsar sites, which could be added to the 180 current Mediterranean Ramsar sites established based on waterbird criteria (criteria 5 and/or 6). Among these sites, a subset of 32 very important sites reached double the required level for at least one criterion and 95 were not protected by any site conservation status. Coastal wetlands represented half of the Ramsar gap for waterbirds. We identified that an additional 1218 monitored sites could be provisionally considered as internationally important and thus require more survey efforts to assess their status. This study highlights a lack of participation of the Mediterranean countries to build the Ramsar network for wetland protection. Our results should help policymakers and managers to prioritize future Ramsar site designation, notably in the Middle East and Western European region where important gaps were identified.
de Kathrin Weise, Rene Höfer, Jonas Franke, Anis Guelmami, Will Simonson, Javier Muro, Brian O’Connor, Adrian Strauch, Stephan Flink, Jonas Eberle, et al.
In Remote Sensing of Environment, 247 (September, 2020), 111892
En ligne : www.sciencedirect.com[...]
Wetlands are the most fragile and threatened ecosystems worldwide, and also one of the most rapidly declining. At the same time wetlands are typically biodiversity hotspots and provide a range of valuable ecosystem services, such as water supply and purification, disaster risk reduction, climate change adaptation, and carbon sequestration. Pressures on wetlands are likely to further intensify in the coming decades due to increased global demand for land and water, and due to climate change. Stakeholders at all levels of governance have to be involved to slow, stop and reverse these processes. However, the information they need on wetland extent, their ecological character, and their ecosystem services is often scattered, sparse and difficult to find and access. The freely available Sentinel satellite data of the Copernicus Programme, as well as the Landsat archive, provide a comprehensive basis to map and inventory wetland areas (extent), to derive information on the ecological status, as well as long- and short-term trends in wetland characteristics. However, making use of these Earth Observation (EO) resources for robust and standardized wetland monitoring requires expert knowledge on often complex data processing techniques, which impedes practical implementation. In this respect, the Satellite-based Wetland Observation Service (SWOS), a Horizon 2020 funded project (www.swos-service.eu) has developed and made disseminated monitoring approaches based on EO data, specifically designed for less experienced satellite data users. The SWOS monitoring tools aim at assisting countries in conducting national wetland inventories for their Sustainable Development Goals (SDG) reporting and monitoring obligations, and additionally facilitates other monitoring obligations such as those required by the Ramsar Convention and supports decision-making in local conservation activities. The four main components of the SWOS approach are: map and indicator production; software development; capacity building; and initializing the GEO Wetlands Community Portal. Wetland managers and data analysists from more than fifty wetland sites and river basins across Europe, the Middle East, and Africa investigated the benefits and limitations of this EO-based wetland mapping and monitoring approach. We describe research that applies the SWOS tools to test their potential for the mapping of wetlands in a case study based in Albania, and show its effectiveness to derive metrics relevant to the monitoring of SDG indicator 6.6.1.Multitemporal optical and radar metrics for wetland mapping at national level in Albania
de Javier Muro, Ana Varea, Adrian Strauch, Anis Guelmami, Eleni Fitoka, Frank Thonfeld, Bernd Diekkrüger, Björn Waske
In Heliyon, 6(8) (August, 2020), e04496
En ligne : linkinghub.elsevier.com[...]
Wetlands are highly dynamic, with many natural and anthropogenic drivers causing seasonal, periodic or permanent changes in their structure and composition. Thus, it is necessary to use time series of images for accurate classifications and monitoring. We used all available Sentinel-1 and Sentinel-2 images to produce a national wetlands map for Albania. We derived different indices and temporal metrics and investigated their impacts and synergies in terms of mapping accuracy. Best results were achieved when combining Sentinel-1 with Sentinel-2 and its derived indices. We reduced systematic errors and increased the thematic resolution using morphometric characteristics and knowledge-based rules, achieving an overall accuracy of 82%. Results were also validated against field inventories. This methodology can be reproducible to other countries and can be made operational for an integrated planning that considers the food, water, and energy nexus.
de Elie Gaget, Thomas Galewski, Frédéric Jiguet, Anis Guelmami, Christian Perennou, Coralie Beltrame, Isabelle Le Viol
In Conservation Biology, 34(4) (August, 2020)
En ligne : conbio.onlinelibrary.wiley.com[...]
While the impacts of climate and land use changes on biodiversity have been widely documented, their joint effects remain poorly understood. We evaluated how non-breeding waterbird communities adjust to climate warming along a gradient of land use change. Using mid-winter waterbird counts (132 species) at 164 major non-breeding sites in 22 Mediterranean countries, we assessed the changes in species composition during 1991–2010, regarding thermal niche position and breadth, in response to regional and local winter temperature anomalies and to natural habitat conversion. We showed that in response to the temperature increase, communities became relatively richer in warm-dwelling species, but less where natural habitat conversion occurred. At the sites affected by natural habitat conversion, the overall species richness decreased with time, while the abundance relatively increased for the species with a broader thermal niche, independently of their thermal affinities. The strong negative relationship between natural habitat conversion and community adjustment to temperature increases suggests an antagonistic interaction between climate warming and habitat change. Indeed, we found no evidence of community adjustment to climate warming when natural habitat conversion was higher than 5% over 15 years. These results underline the importance of habitat conservation in community adjustment to climate warming. Article impact statement: Waterbird communities do not adjustment to climate warming when natural habitat conversion is >5% over 15 years. This article is protected by copyright. All rights reservedMediterranean wetland conservation in the context of climate and land cover change
de Roxanne Leberger, Ilse R. Geijzendorffer, Elie Gaget, Anis Guelmami, Thomas Galewski, Henrique M. Pereira, Carlos A. Guerra
In Regional Environmental Change, 20(2) (6/2020), 67
En ligne : link.springer.com[...]
Wetlands are known to support diverse and unique species assemblages. Globally, but particularly in the Mediterranean basin, they are threatened by climate change and natural habitat loss. Despite an alarming decline of wetlands over the last century, standardised and systematic site assessments at large scale do not exist. Here, we perform an integrated assessment of Mediterranean wetlands by evaluating the combination of wetland protection and anthropogenic pressures, namely climate and land cover change, and the subsequent impact on wintering waterbirds. We used a multivariate partial triadic analysis to quantify climate and land cover change for each site between 1990 and 2005. We found that wetland sites in the southeast of the Mediterranean basin combined low or no protection cover with the highest increases in temperature and losses in natural habitats. Despite these findings, these sites also lack observation data on biodiversity, which may underestimate the resulting impacts. However, there are examples where active conservation measurements contributed positively to slow down wetlands’ reduction. Biodiversity data coverage needs to be ensured, regularly updated, and extended across sites regardless of their protection level, to allow for the assessment of biodiversity trends. This should be further extended to include current investments in remote sensing approaches.Introducing WIW for Detecting the Presence of Water in Wetlands with Landsat and Sentinel Satellites
de Gaëtan Lefebvre, Aurélie Davranche, Loic Willm, Julie Campagna, Lauren Redmond, Clément Merle, Anis Guelmami, Brigitte Poulin
In Remote Sensing, 11(19) (Septembre, 2019), 18
En ligne : www.mdpi.com[...]
Many wetlands are characterized by a vegetation cover of variable height and density over time. Tracking spatio-temporal changes in inundation patterns of these wetlands remains a challenge for remote sensing. Water In Wetlands (WIW) was predicted using a dichotomous partitioning of reflectance values encoded based on ground-truth (n = 4038) and optical-space derived (n = 7016) data covering all land cover types (n = 17) found in the Rhône delta, southern France. The models were developed with spectral data from Sentinel 2, Landsat 7, and Landsat 8 sensors, hence providing a monitoring tool that covers a 35-year period (same sensor for Landsat 5 and 7). A single model combining the near infrared (NIR ≤ 0.1558 to 0.1804, depending on sensors) and short-wave infrared (SWIR2 ≤ 0.0871 to 0.1131) wavelengths was identified by three independent analyses, each one using a different satellite. Overall accuracy of water maps ranged from 89% to 94% for the training samples and from 90% to 94% for the validation samples, encompassing standard water indices that systematically underestimate flooding duration under vegetation cover. Sentinel 2 provided the highest performance with a kappa coefficient of 0.82 for both samples. Such tool will be most useful for monitoring the water dynamics of seasonal wetlands, which are particularly sensitive to climate change while providing multiple services to humankind. Considering the high temporal resolution of Sentinel 2 (every 5 days), cumulative water maps built with the WIW logical rule could further be used for mapping a wide range of wetlands which are either periodically or permanently flooded.L’état des zones humides dans le monde et en Méditerranée
de Christian Perennou, Laurent Chazee, Thomas Galewski, Ilse Geijzendorffer, Anis Guelmami
In Zones Humides Infos, 97-98 (Eté 2019), 20-21
de Nouara Benslimane, Khémissa Chakri, Dalal Haiahem, Anis Guelmami, Farrah Samraoui, Boudjema Samraoui
In Journal of Insect Conservation, 23(3) (February, 2019)
En ligne : doi.org[...]
In arid North Africa, dune ponds qualify as hotspots of aquatic biodiversity, offering numerous sustainable ecosystem services. Despite mounting anthropogenic pressures that threaten their integrity, the overall consequences of these changes have yet to be documented and no strategy to mitigate potential impacts is being implemented. We monitored four dune ponds in northeast Algeria during five hydrological cycles spanning the period 1996–2013. The analysis revealed a steep decline in species richness (47%) and abundance (94%) over the study period. Remote sensing-based data indicated that marked human-induced changes in and around these dune ponds have over time led to a substantial expansion of built areas and cultivated plots and a reduction in both natural wet- and dry-land habitats. Fish predation by the introduced fish, Gambusia holbrooki, may have had both direct and indirect impacts on notonectids. We argue that aquatic hemipterans have undergone an alarming reduction driven by a combination of invasive species, human encroachment, agricultural runoffs, and possibly, climate change.A More Effective Ramsar Convention for the Conservation of Mediterranean Wetlands
de Ilse R. Geijzendorffer, Coralie Beltrame, Laurent Chazee, Elie Gaget, Thomas Galewski, Anis Guelmami, Christian Perennou, Nadège Popoff, Carlos A. Guerra, Roxanne Leberger, et al.
In Frontiers in Ecology and Evolution, 7 (February, 2019)
En ligne : www.frontiersin.org[...]
The Ramsar Convention is the multilateral agreement aimed at protecting wetlands globally. Wetlands are particularly recognized for their role in the Mediterranean biodiversity hotspot by providing key habitats for endemic and migratory species, directly contributing benefits to the lives of people and being an integral part of their culture. In response to this importance, the Mediterranean Wetlands Observatory publishes Mediterranean Wetland Outlooks on the state and trends of Mediterranean wetlands; the first edition in 2012 (MWO1) and the second edition in 2018 (MWO2). In this paper, we used the results of the two Mediterranean Wetland Outlooks to highlight ways to increase the impact of the Ramsar Convention by identifying the spatial dimensions of detected biodiversity trends as well as the societal developments and estimated impacts of global change and protection status.
de Asma Kahli, Ghania Belhadj, Elie Gaget, Clément Merle, Anis Guelmami
In La Terre et la Vie, 73(4) (2018), 431-445
En ligne : hdl.handle.net[...]
Les forêts humides sont parmi les écosystèmes humides les plus dégradés et les plus menacés dans le monde. En Algérie, elles représentent un ensemble d’habitats forestiers singuliers, fragiles et rares. La région d’El Kala, à l’extrême nord-est du pays, abrite de nombreuses zones humides uniques (lacs, marais, prairies humides, lagunes, etc.), parmi lesquelles quelques-unes des plus importantes formations de forêts humides en Afrique du Nord. L’objectif de cette étude est de développer une nouvelle approche cartographique afin de localiser et de délimiter ces formations à l’aide des outils d’observation de la Terre. Elle se base sur une combinaison d’indices topographiques et hydro-géomorphologiques, issus des Modèles Numériques de Terrain (MNT), de variables spectrales calculées à partir des images Landsat-8 et de données collectées sur terrain.Mapping Mediterranean Wetlands With Remote Sensing: A Good-Looking Map Is Not Always a Good Map
de Christian Perennou, Anis Guelmami, Marc Paganini, Petra Philipson, Brigitte Poulin, Adrian Strauch, Christian Tottrup, John Truckenbrodt, Ilse R. Geijzendorffer, David A. Bohan, et al.
In Advances in Ecological Research, 58(1) (2018), 243-277
En ligne : www.sciencedirect.com[...]
Wetlands are a key habitat within the Mediterranean biodiversity hotspot and provide important ecosystem services for human well-being. Remote sensing (RS) has significantly boosted our ability to monitor changes in Mediterranean wetlands, especially in areas where little information is being collected. However, its application to wetlands has sometimes been flawed with uncertainties and unrecognized errors, to a large extent due to the inherent and specific ecological characteristics of Mediterranean wetlands. We present here an overview of the state of the art on RS techniques for mapping and monitoring Mediterranean wetlands, and the remaining challenges: delineating and separating wetland habitat types; mapping water dynamics inside wetlands; and detecting actual wetland trends over time in a context of high, natural variability. The most important lessons learned are that ecologists’ knowledge need to be integrated with RS expertise to achieve a valuable monitoring approach of these ecosystems.
de Mohammed El Madihi, Laïla Rhazi, Maarten Van den Broeck, Mouhssine Rhazi, Aline Waterkeyn, Er-riyahi Saber, Siham Bouahim, Moustapha Arahou, Abdelmajid Zouahri, Anis Guelmami, et al.
In Plant Ecology & Diversity, 10(1) (2017-07-24), 1-19
En ligne : www.tandfonline.com[...]
Background: Temporary ponds, an abundant habitat in the Maghreb region and notably in Morocco, have a high conservation value. However, they are mainly known from the north of the country.
Aims: The aim of this work was to characterise the vegetation of Moroccan temporary ponds along a combined gradient of latitude and anthropogenic pressure.
Methods: Eighty-five ponds distributed along a north–south gradient of 750 km were sampled. For each pond, all vegetation was surveyed (flooded and dry parts) and the local abiotic characteristics were measured during two successive hydrological cycles. The prevailing anthropogenic pressures were also identified and were attributed an impact score.
Results: Eighty-one characteristic pond species (including 17 rare species) were recorded, with several new distribution data in the southern part of the latitudinal gradient. Plant communities were related to climatic and anthropogenic factors, but mostly to local factors, such as maximum water depth and soil pH. The northern ponds (wettest macroclimate) were rich in characteristic species and rare species, while the southern (driest macroclimate) ponds were more species poor.
Conclusions: In addition to the direct impact of increasing human activity, a further reduction of the floristic richness of temporary ponds is expected due to climatic changes. This is particularly the case for characteristic species which have a high conservation value.
de Coralie Beltrame, Christian Perennou, Anis Guelmami
In Méditerranée, 125 (2015), 97-111
Les zones humides méditerranéennes dans leur ensemble, écosystèmes de haute valeur pour la biodiversité, ont perdu environ 50 % de leur superficie au cours du xx e siècle. Par ailleurs, le littoral méditerranéen est soumis à de fortes pressions dues à l’urbanisation, au tourisme mais aussi au développement d ’infrastructures industrielles et de transport. Il y a donc dans les zones humides littorales méditerranéennes une convergence d’enjeux écologiques, sociaux et économiques. L’évolution de l’occupation du sol a été caractérisée dans 214 d’entre elles entre 1975 et 2005. En leur sein, la superficie des habitats humides naturels a diminué de 10 % en 30 ans, soit une perte de 1329 km². À l’inverse, les habitats humides d’origine anthropique ont augmenté de 105 %, c’est -à-dire un gain de 854 km². Pendant cette période, la principale pression directe sur les habitats humides naturels a été l’agriculture puisque 71 % des habitats humides perdus l’ont été au profit des milieux agricoles. L’urbanisation a eu un impact direct moindre mais elle a entrainé la conversion des terres agricoles périurbaines, qui se sont report ées vers les habitats naturels périphériques. Mots-clés : Méditerranée, zone humide littorale, SIG, télédétection, artificialisation, occupation du sol, pression agricole, pression urbaine / Overall, Mediterranean wetlands are very important ecosystems for biodiversity. Approximately half their area was lost during the 20 th century. The Mediterranean coast is also under heavy pressure due to urbanization, tourism and development of industrial and transport infrastructures. The Mediterranean coastal wetlands thus represent a convergence point of ecological, human and economic issues. Changes in land cover between 1975 and 2005 were characterized in 214 of them. The area of natural wetland habitats decreased by 10 % in 30 years, i.e. a loss of 1329 km². At the same time, artificial wetland habitats increased by 105 %, i.e. a gain of 854 km². The main direct pressure on natural wetland habitats was agriculture, with 71 % of them converted into agricultural areas. Urbanization had less direct impact but largely affected agricultural areas, which in turn were displaced onto natural habitats.Development of an Indicator to Monitor Mediterranean Wetlands (2015)
de A. Sanchez, D. Abdul Malak, Anis Guelmami, Christian Perennou
2015Existing areas and past changes of wetland extent in the Mediterranean region: an overview
de Christian Perennou, C. Beltrame, Anis Guelmami, P. Tomas Vives, Pierre Caessteker
In Ecologia Mediterranea, 38(2) (2012), 53-66
En ligne : ecologia-mediterranea.univ-avignon.fr[...]
