Christophe Proisy

• PhD, Habilitation à Diriger les Recherches
• Researcher at Institute of Research for Development (Cayenne French Guiana)

Mangroves of the North Brazil Shelf (NBS) are a regional ecosystem subgroup (level 4 unit of the IUCN Global Ecosystem Typology). It includes the marine ecoregions of Amazonia, Guianan, Northeastern Brazil, and the Southern Caribbean. The NBS mangrove province had a mapped extent in 2020 of 13204.0 km2, representing 9.0% of the global mangrove area...

This study outlines advancements in mangrove monitoring using Earth Observation (EO) technologies, highlighting a transition from historical cartography to modern, near-real-time monitoring systems. Mangroves, critical for biodiversity, climate regulation, and coastal protection, face threats from climate change and human activities. The need for a...

Understanding how mangroves respond to sea level rise is critical for coastal management and conservation. This study investigates the feasibility of two remote sensing techniques, Light Detection and Ranging (LiDAR) and Structure-from-Motion (SfM) photogrammetry, to monitor changes in mud elevation that are critical to mangrove establishment dynam...

On a worldwide scale, land use and land cover changes (LULCC) is a major driver of global change and biodiversity erosion. This study aims to monitor at the scale of Sri Lanka, LULCC and vegetation dynamics, to identify the main changes and their drivers. It places emphasis on multiscale geospatial monitoring with satellite data but also mobilises...

French Guiana has 320 km of coastline, 80% of which is covered by mangroves. Situated at the heart of the Amazonian sediment dispersal system, which is responsible for the migration of huge mudbanks, it’s one of the most unstable coastal dynamics in the world. Spatial observations have shown that both cross-shore mangrove removal and establishment...

French Guiana mangrove and coastal dynamics

Remote sensing of the Guianas coast

Predicting carbon fluxes along muddy mangrove coastlines

Highlighting spatiotemporal changes occurring within mangrove habitats at the finest possible scale could contribute fundamental knowledge and data for local sustainable management. This study presents the current situation of the Pichavaram mangrove area, a coastal region of Southeast India prone to both cyclones and reduced freshwater inflow. Bas...

This article is a travel story about a 10-day expedition to the Amazon River mouth that happened at the end of march 2013 for a study of forest carbon in the Tropics. The aim is to relate my personal feelings during a journey to a remote area of study, those feelings that forge motivations and collaborations, support new and relevant scientific hyp...

Can mangroves help to predict coastal changes ?

Mangroves and aquaculture should share a common sustainable vision

Coastal instability is not tantamount to vulnerability of mangroves everywhere but rather brings out their exceptional ecological adaptability to cope with morphosedimentary processes. This adaptability has, however, not yet been sufficiently assessed regarding its ability to provide early warning of severe risks induced by marine erosional process...

The geomorphology of mangrove ecosystems is strongly influenced by hydrodynamic factors. Mangrove growth is conditional on water and sediment budgets at the coastal interface. This basic ecological principle has been ignored in many mangrove restoration or rehabilitation programs, leading to failures in the design of successful and cost-effective e...

European Water Framework Directive is enforced in five tropical French Oversea Territories where mangroves are present. Developing bioindication tools to support the ecosystem-based management approach of the Directive is needed. A series of expert workshops was organized and led to the proposal of a strategy and of an applied research program to d...

Despite the low tree diversity and scarcity of the understory vegetation, the high morphological plasticity of mangrove trees induces, at the stand level, a very large variability of forest structures that need to be mapped for assessing the functioning of such complex ecosystems. Fully constrained linear spectral unmixing (FCLSU) of very high spat...

Each mangrove region has a specific history which needs to be understood as it is a central component for adapting current conservation plans to changing coastal conditions induced by increasing natural or human pressures. As these latter impact the functioning, physiognomy and extent of mangroves, it is urgent to design and implement monitoring pr...

Preserving tropical vegetation biomes stems with an accurate identification of constituent plant species. In Asia, identifying mangrove plant species is particularly required in biodiversity assessment, restoration or preservation programs, which are pivotal components of the ecosystem's preservation from unsustainable anthropogenic activities. The...

Kalivelli wetland is a brackish shallow lake located on the Coromandal Coast in Villupuram and Cheyyur districts, North of Pondicherry. The lake is connected to the Bay of Bengal by the brackish Uppukalli creek and the Edayanthittu Estuary. Although it has been identified as one of the major wetlands in the Coromandal Coast, if not in India, the Ka...

The French Institute of Pondicherry and the CIFEODD organized a French-speaking international conference in Pondicherry (India) on 'Ecosystems and sustainable development' with the main theme of "human and natural transformations of terrestrial and coastal ecosystems", from 23rd to 25th October 2018. The following topics were addressed: Topic 1: Hu...

Leaf mass per area (LMA) and leaf equivalent water thickness (EWT) are key leaf functional traits providing information for many applications including ecosystem functioning modeling and fire risk management. In this paper, we investigate two common conclusions generally made for LMA and EWT estimation based on leaf optical properties in the near-i...

Industrial and urban development along the coast may exacerbate the changes induced by oceano-climatic processes to such an extent that the coast becomes uninhabitable. This paper presents a baseline study carried out on the 360 km long Coromandel coast of Tamil Nadu's (TN) Bay of Bengal coast, Southeast India. About 30% of the 72 million inhabitan...

The role of mangroves in the blue carbon stock is critical and requires special focus. Mangroves are carbon-rich forests that are not in steady-state equilibrium at the decadal time scale. Over the last decades, the structure and zonation of mangroves have been largely disturbed by coastal changes and land use conversions. The amount of time since...

Industrial and urban development along the coast may exacerbate the changes induced by oceano-climatic processes to such an extent that the coast becomes uninhabitable. This paper presents a baseline study carried out on the 360 km-long Coromandel coast of Tamil Nadu's (TN) Bay of Bengal coast, Southeast India. About 30% of the 72 million inhabitan...

Very high spatial resolution (VHSR) optical satellite imagery has shown good potential to provide non-saturating proxies of tropical forest aboveground biomass (AGB) from the analysis of canopy texture, for instance through the Fourier Transform Textural Ordination method. Empirical case studies however showed that the relationship between Fourier...

Revegetation of abandoned aquaculture regions should be a priority for any integrated coastal zone management (ICZM). This paper examines the potential of a matchless time series of 20 very high spatial resolution (VHSR) optical satellite images acquired for mapping trends in the evolution of mangrove forests from 2001 to 2015 in an estuary fragmen...

From the 1980's, Indonesian shrimp production has continuously increased through a large expansion of cultured areas and an intensification of the production. As consequences of diseases and environmental degradations linked to this development, there are currently 250,000 ha of abandoned ponds in Indonesia. To implement effective procedure to unde...

Click on the link for the entire article (and the rest of the special issue) : https://espacepolitique.revues.org/3805 In 2010, a collective of 8 geographers and sociologists launched the research program “Informality, Power and the Other Side of Urban Spaces - Inverses”. This text is a description of the process and different stages followed by t...

Assessing the role of tropical forests in biogeochemical cycles is one of the greatest scientific challenges of the century. The impact of climate change could increase the mortality of tropical forests and decrease their ability to store atmospheric carbon dioxide. Efforts to model the forest dynamics in these regions are hindered by the lack of g...

Key message We estimated aboveground biomass of large mangrove trees from terrestrial Lidar measurements. This makes the first attempt to extend mangrove biomass equations validity range to trunk diameter reaching 125 cm. Abstract Accurately determining biomass of large trees is crucial for reliable biomass analyses in most tropical forests, but...

Mapping zonations of mangrove species (ZMS) is important when assessing the functioning of such specific ecosystems. However, the reproducibility of remote sensing methods for discriminating and mapping mangrove habitats is often overstated due to the lack of temporal observations. Here, we investigated the potential use of temporal series of high-...

Mapping zonations of mangrove species (ZMS) is important when assessing the functioning of such specific ecosystems. However, the reproducibility of remote sensing methods for discriminating and mapping mangrove habitats is often overstated due to the lack of temporal observations. Here, we investigated the potential use of temporal series of high-...

We present a new landscape-modelling framework based on a domain-specific language called Ocelet that is used to question our understanding of how mangrove forests cope with fast-changing muddy seashores. For the demonstration, we selected the coast of French Guiana where mangrove physiognomy and extent continuously vary due to successive and recur...

Presented during International Coastal Symposium

We estimated aboveground biomass of large mangrove trees from terrestrial Lidar measurements. This makes the first attempt to extend mangrove biomass equations validity range to trunk diameter reaching 125 cm. Accurately determining biomass of large trees is crucial for reliable biomass analyses in most tropical forests, but most allometric models...

– The use of very high resolution (VHR) optical remote sensing is promising for the study of mangrove forest dynamics. – The challenge is to develop methods of remote sensing capable of describing the variability of the forest parameters independent of the variability of the image acquisition configurations: The FOTO method of canopy grain analysi...

Assessing the role of tropical forests in biogeochemical cycles is one of the greatest scientific challenges of the century. The impact of climate change could increase the mortality of tropical forests and decrease their ability to store atmospheric carbon dioxide. Efforts to model the forest dynamics in these regions are hindered by the lack of g...

HYPXIM, is a preliminary study (i.e. phase 0) which begun in 2009, lead and funded by CNES. The synthesis of the needs collegially addressed by a national group of hyperspectral experts, helped us to set up the mission requirements in terms of spectral domain [0,4-2.5 microns), spectral resolution (10nm), signal-to-noise ratio (depends on the rang...

Mangrove restoration has been attempted in the 7 km² Perancak Estuary, Bali since the 90's following shrimp farming loss of profitability. We characterized the surface types of estuarine zone and monitored mangrove changes since 2001 using a series of 20 very high resolution satellite images acquired over the estuary. Mangrove development was furth...

Light Detection and Ranging (Lidar) is a state of the art technology to assess forest aboveground biomass (AGB). To date, methods developed to relate Lidar metrics with forest parameters were built upon the vertical component of the data. In multi-layered tropical forests, signal penetration might be restricted, limiting the efficiency of these met...

Light Detection and Ranging (Lidar) is a state of the art technology to assess forest aboveground biomass (AGB). To date, methods developed to relate Lidar metrics with forest parameters were built upon the vertical component of the data. In multi-layered tropical forests, signal penetration might be restricted, limiting the efficiency of these met...

AimThe goal of the study was to quantify changes in the extent of mangroves since the mid-twentieth century and to test the hypothesis that these changes are driven by ocean waves.LocationThe pristine 300-km-long coast of French Guiana, South America.Methods We produced time series of mangrove maps using archival remote sensing images. We retrieved...

There is a need to document how fast mangrove coasts are changing. Within the framework of the INDESO project, we are implementing methods for monitoring changes in Indonesian mangroves over the past decade. The Perancak river estuary, Jembrana, Bali was selected as a pilot site to analyze the impact of aquaculture and plantation practices in a 7 k...

Sustainable management of mangroves depends on our ability to maintain ecosystem functions. It requires a careful monitoring of several forest characteristics such as the species composition. Very high resolution multispectral satellite images provide pivotal information at the individual tree scale that may support identification and mapping of sp...

2015 is declared as the Mangrove Year by the CNRS-INEE (www.cnrs.fr) and the IRD (www.ird.fr), two leading French research institutes on natural ecosystems. As a contribution to this initiative, we prepared the directory of persons conducting scientific works on mangroves from French research laboratories, national or local organizations and privat...

In tropical forests, ecological processes heavily depend on the structure of the canopy (size, shape, dominance of trees) and also the ability of each species to capture light and nutrients in the soil. Airborne HR imaging spectroscopy has demonstrated its potential in tropical environments: Confirmation that trees structure combined with leaf bioc...

Large-scale characterization of tropical rainforest is a challenge for their conservation and management. Very high spatial resolution images as provided by the Pléiades satellites offer new opportunities to study the structural organization of heterogeneous rainforests with limited accessibility. In this study, we have evaluated the potential of P...

Large-scale characterization of tropical rainforest is a challenge for their conservation and management. Very high spatial resolution images as provided by the Pléiades satellites offer new opportunities to study the structural organization of heterogeneous rainforests with limited accessibility. In this study, we have evaluated the potential of P...

Very high resolution (VHR) satellite images provide crucial information on fast changing coastal regions of the world. Within the framework of the INDESO project, we designed a specific application dedicated to the monitoring of mangroves in Indonesia. In this work, we focused on the case study of the Perancak river estuary, Jembrana, Bali. The est...

Large-scale characterization of tropical rain forest structure is a long-held challenge in environmental sciences with critical stakes such as above-ground biomass or carbon stock estimation. Very high spatial resolution images, as provided by the Pléiades satellites, offer new opportunities to study the structural organization of heterogeneous rai...

Mangroves are critical ecosystems given their key role in conserving biodiversity, protecting coastlines from erosion and supporting coastal resources. They may be impacted by oil and gas activities, either directly or indirectly. Restoring them is therefore of prime importance. In the Mahakam Delta, oil and gas exploration and production have been...

La description des structures végétales fournit des informations essentielles à une meilleure compréhension de la dynamique des forêts. Que ce soit à l'échelle de l'arbre, des peuplements ou des massifs forestiers, notre capacité à mesurer et à suivre sur le terrain l'évolution des paramètres structuraux et botaniques qui décrivent cette dynamique...

The capability of French Guiana mangroves to cope with coastal changes is addressed. Our ambition is to continue sharing interdisciplinary experience and strengthening international cooperation through the setting up of a 'Mangrove Watch Station' (MWS). By year-end 2014, our objective is to write specifications for the standardization of both the M...

Local tree density may vary in young Eucalyptus plantations under the effects of environmental condi-tions or inadequate management, and these variations need to be mapped over large areas as they have a significant impact on the final biomass harvested. High spatial resolution optical satellite images have the potential to provide crucial informat...

The structural organization of a forest canopy is an important descriptor that may provide spatial information for vegetation mapping and management planning, such as attributes of plant species distributions, intensity of disturbances, aboveground biomass or carbon stock. A variety of airborne and satellite images characterize forest stands from a...

Depuis plus de 25 ans des travaux de recherche interdisciplinaires sont conduits pour comprendre et suivre la dynamique du littoral guyanais par les organismes de recherche comme le CNRS, l'IFREMER ou l'IRD et plusieurs Universités de m étropole avec l'appui de PME telle que SIRS et des grands industriels (Astrium GEO-Information Services). Dans le...

Very high spatial resolution (VHSR) satellite images provide interesting information for parameterizing tree-scale forest process-based models, and in particular their light absorption submodels, which is at the basis of photosynthesis calculation. Such tree-scale models require a large amount of field measurements to describe the forest ecosystems...

Reducing Emissions from Deforestation and Forest Degradation (REDD) in efforts to combat climate change requires participating countries to periodically assess their forest resources on a national scale. Such a process is particularly challenging in the tropics because of technical difficulties related to large aboveground forest biomass stocks, re...

Projet FOTO_METRICS Apport de la mesure du grain de canopée dans les images THR pour l'estimation des paramètres forestiers en mangroves de forte biomasse. Résumé: Les images Pléiades ont un réel potentiel pour estimer les paramètres forestiers. En effet, la texture des images à très haute résolution spatiale apporte une information importante pour...

Using remote sensing to provide reliable information over extensive areas of dense and heterogeneous tropical forests is a challenging task. Not only is the task challenging, but it also has become closely related to global concerns about reducing greenhouse gas emissions from deforestation and forest degradation, also known as the REDD process. Th...

Individual tree detection methods are more and more present, and improve, in forestry and silviculture domains with the increasing availability of satellite metric imagery [2–7]. Automatic detection on these very high spatial resolution images aims to determine the tree positions and crown sizes. In this paper, we use a mathematical model based on...

• Context Remote sensing methods, and in particular very high (metric) resolution optical imagery, are essential assets to obtain forest structure data that cannot be measured from the ground because they are too difficult to measure or because the areas to sample are too large or inaccessible. • Aim To understand what kind of, and how precisely an...

Quantifying and monitoring the structure and degradation of tropical forests over regional to global scales is gaining increasing scientific and societal importance. Reliable automated methods are only beginning to appear; for instance, through the recent development of textural approaches applied to high resolution optical imagery. In particular,...

The aim of this study is to predict the short-term evolution of the surface areas of mangroves colonizing the mud banks of French Guiana from the comparative analysis of a series of satellite images. Two banks have been thus monitored: those of Kourou and Sinnamary. Sediment concentration values, grain sizes and topographic data were obtained for t...

Numéro 23-24 Juillet-Décembre Lettre d'informations de l'UMR AMAP Edito Au 1er avril prochain, après une carrière professionnelle bien remplie, je quitterai définitivement AMAP pour me consacrer à d'autres activités plus personnelles. Depuis mon arrivée à l' «unité de modélisation» (Cirad-Inra) voilà plus de 17 ans, j'ai assisté (et participé) à de...

The 1500 km-long coast of South America between the Amazon and the Orinoco river mouths is the world's muddiest. This is due to the huge suspended-sediment discharge of the Amazon River (106 × 754 tons yr− 1 ± 9%), part of which is transported alongshore as mud banks. Mud-bank formation is controlled by the physical oceanography of the continental...

Tropical forests are complex ecosystems where the potential of remote sensing has not yet been fully realized. The increasing availability of satellite metric imagery along with canopy altimetry from airborne LiDAR open new prospects to detect individual trees. For this objective, we optimized, calibrated and applied a model based on marked point p...

Characterisation of forest structure is a major stake for forestry, species conservation, carbon stock estimates and many forest ecology and management issues. At large scale natural forest structure tends to vary according to climate and geomorphomology (Paget, 1999; Steege et al., 2006) while soil characteristics (and notably water regime) and sy...