**Defined by the IUCN in 2009, the concept of Nature-based Solutions (NBS) is founded on the idea that natural processes, and not just technological ones, can make a significant contribution to tackling major contemporary challenges such as climate change and biodiversity erosion. Nature provides vital services to all living things, and in particular to humankind. It is therefore essential to preserve, restore and manage it sustainably to ensure our future.**

![Nature-Based-Solutions-forest.jpg](https://backoffice.reforestaction.com/uploads/Nature_Based_Solutions_forest_f54ea0ac1f.jpg)

## What are Nature-based Solutions?

Nature-based Solutions are defined by IUCN (International Union for Conservation of Nature) as “actions to protect, sustainably manage and restore natural or modified ecosystems to directly address societal challenges in an effective and adaptive manner, while ensuring human well-being and producing benefits for biodiversity.”

This concept was formulated by IUCN at the Copenhagen Conference in 2009, when forests were proposed as a solution for mitigating climate change. It was at COP21 in 2015 that the place of Nature-based Solutions in climate action was recognized by States, notably via the Paris Agreement.

These are actions that aim to protect, restore and sustainably manage natural ecosystems - be they forests, rivers, wetlands or even bocage meadows - in a logic of mutual benefit, since these ecosystems generate benefits for humanity. Nature-based Solutions also bring benefits for [biodiversity](https://www.reforestaction.com/en/magazine/what-biodiversity-definition-and-issues), by integrating this objective into the very design and implementation of these actions.

![EN_NbS.jpg](https://backoffice.reforestaction.com/uploads/EN_Nb_S_775d13cbc8.jpg)

## How are ecosystems and human societies interconnected?

### A multitude of services to humanity

Ecosystems are multifunctional by nature. The variety of ecosystem functions they produce are not man-made, but the result of slow, patient work shaped by Nature over millions of years. Today, [natural ecosystems](https://www.reforestaction.com/en/magazine/reconnecting-living-sustainable-humanity) make vital contributions to people's lives, such as the production of food, energy and raw materials, as well as a multitude of ecosystem services. For example, forests store carbon, regulate the water cycle, limit local heat peaks, reduce the risk of soil runoff and landslides, and meet vital human needs such as the production of timber and energy, food and medicinal products, and places of well-being and recreation.

### Nature's services to human societies are not unlimited

The worldwide overexploitation of ecosystems leads to their degradation, and thus to their inability to provide resources in the long term. The Global Footprint Network's annual Earth Overshoot Day is a direct illustration of this idea. This date, which marks the day when humanity has consumed all the natural resources the Earth can produce in one year, is obtained by comparing mankind's ecological footprint (which measures the exploitation of the Earth's natural resources) with the planet's biocapacity (its capacity to replenish its reserves and absorb greenhouse gases). Still in surplus in 1961, with a quarter of its reserves unused, the Earth became in deficit in the early 1970s. This day was changed from October 10 in 1999 to August 1 in 2024.

In most regions of the world today, Nature has been significantly altered by multiple human factors, and the vast majority of indicators relating to ecosystems and biodiversity show a rapid decline. For example, the IPBES estimates that today :

- 75% of natural terrestrial environments are degraded;
- 66% of oceans have been altered;
- 85% of wetlands have disappeared;
- 5% of the world's animal and plant species are threatened.

Forests, which are home to 80% of the Earth's biodiversity and support 25% of the world's population, are in constant decline. On a global scale, forest area today represents around 68% of its estimated pre-industrial level. According to the FAO, 240 million hectares of forest were lost to deforestation in tropical zones between 1990 and 2015. In temperate zones, the effects of climate change are affecting forest health: 42% of tree species are now threatened with extinction in Europe, according to the IUCN. Forest animal biodiversity has fallen by [53%](https://www.dw.com/en/worlds-forest-animal-population-sinks-drastically-wwf-report/a-50015580) since 1970.

### Ecosystem degradation also weakens populations

Ecosystems, biodiversity and climate are interdependent. Ecosystems and their biodiversity influence climate, helping to regulate temperature and precipitation. They are essential players in the carbon, water and nitrogen cycles. They help absorb some of the heat and greenhouse gases emitted by human activities. These feedbacks between climate and biodiversity are at the origin of the dynamic balance of the environment in which human societies have developed, and which is today affected by both climate and ecosystem changes. Alterations to ecosystems and the climate-biodiversity pair make human beings more vulnerable, with the loss of food sources, the deterioration of water quality, the [development of new diseases](https://www.reforestaction.com/en/magazine/destruction-ecosystems-favours-rise-new-diseases-and-pandemics) and the exposure of societies to extreme climatic events (droughts, storms, etc.).

Strategies and actions to combat climate change must therefore not only drastically reduce greenhouse gas emissions, but also invest in protecting ecosystems. [Healthy ecosystems](https://www.reforestaction.com/en/magazine/ecosystem-restoration-essential-climate-and-biodiversity) not only help mitigate climate change, but also enable human societies to adapt to its consequences.

![Wooded hills with women's tree-planting communities](https://backoffice.reforestaction.com/uploads/Nature_based_solutions_communities_c9eebab421.jpg)

## Nature-based solutions for today's societal challenges

### Preserving nature is essential to ensure the future of human societies and businesses

According to the IUCN, the use of NbS would enable us to achieve current societal objectives such as :

- Reducing natural hazards
- Socio-economic development
- Food security
- Water and energy supply
- Health and well-being for all
- Adapting territories to climate change
- Mitigating the effects of climate change on populations (rising sea levels, fires, heatwaves...)

According to the IPBES, these natural solutions will account for 37% of the climate change mitigation measures needed by 2030 to achieve the goal of global warming below 2°C by 2100. But implementing NbS on the scale required to meet these societal challenges requires the involvement of all stakeholders, including private sector companies.

### Forests: a key component of Nature-based Solutions

NbS value the services provided by ecosystems that have been preserved, restored or sustainably managed, and are based on various underlying concepts listed by the IUCN. Among these Nature-based Solutions is the restoration of forest landscapes. This process aims to mobilize and involve local communities in restoring the multifunctionality of forests, in order to sustainably meet human needs. This type of project can be implemented through a variety of actions involving the preservation, restoration and sustainable management of forests. All these actions enhance forest biodiversity, and increase carbon capture, which helps mitigate the risks of climate change:
- Preservation of existing forests in good ecological condition
- Restoration of degraded forests or creation of forest ecosystems
- Adoption of sustainable forest management practices
- Creation of protected areas (national or regional parks, nature reserves, etc.) to protect associated territories and preserve ecosystem services
- Reforestation and ecological restoration of degraded forest habitats using adapted and diverse species, giving priority to indigenous species;
- Creation of hedgerows and [agroforestry systems](https://www.reforestaction.com/en/magazine/agroforestry) to regulate climate and the water cycle, conserve soil and create biological corridors for flora and fauna;
- Exclusion of unsustainable practices such as monospecific plantations, clear-cutting that weakens soils and overexploitation of stands;
- Development of [Assisted Natural Regeneration](https://www.reforestaction.com/en/magazine/assisted-natural-regeneration-complementary-solution-tree-planting-restore-degraded-forests);
- Creation of islands of senescence, made up of ageing trees which, as they decompose, promote the fertility of forest soils, the main reservoir of biodiversity in the forest;
- Promoting wood products from sustainably managed forests.

![Nature-based-solutions-overview.jpg](https://backoffice.reforestaction.com/uploads/Nature_based_solutions_overview_9e487805c8.jpg)

## Developing Nature-based Solutions with Reforest'Action

Reforest'Action offers Nature-based Solutions that enable companies to:
- Contribute to [global carbon neutrality](https://www.reforestaction.com/en/carbon-neutrality-solutions)
- Develop [regenerative agriculture](https://www.reforestaction.com/en/regenerative-agriculture) within their value chains 
- Support the [restoration of forest ecosystems](https://www.reforestaction.com/en/ecosystems-restoration) 

Our mission: to regenerate terrestrial ecosystems on a large scale to meet global environmental challenges and support corporate climate and transformation strategies, drawing on our field experience, local communities, research and technology. 

Today, our 1,650 forest and agroforestry projects in 45 countries are creating multiple impacts, based on the stability of ecosystems over time, to combat climate change, protect biodiversity and support local communities. Each project financed by Reforest'Action is thus at the heart of global climate action and Nature-based Solutions. 

At the heart of our approach, monitoring the impact of our projects via our [Research & Development team](https://www.reforestaction.com/en/the-impact) also enables us to optimize their results and deliver reliable and transparent data to investors, by means of key performance indicators, regarding the value generated by our Nature-based Solutions.


**Drawing on the role of healthy ecosystems for human life and the well-being of all, Nature-based Solutions address both climate and biodiversity issues. It is crucial to encourage their development at all scales to meet the Sustainable Development Goals formulated by the UN, and to direct more funds towards restoration in order to act more rapidly and effectively in favor of the climate and biodiversity at the service of all Living Things. If you're interested in Nature-based Solutions, and forestry in particular, please [contact us](https://www.reforestaction.com/en/contact).**



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What are Nature-based Solutions?

**While a quarter of all known plant and animal species are now endangered, initiatives continue to develop to help preserve them. Among these, The Global Biodiversity Standard (TGBS) is the only international standard to recognize and encourage the protection, restoration and enhancement of biodiversity. As part of the TGBS technical and scientific network, Reforest'Action contributes its expertise in forest ecosystem restoration and impact measurement to develop remote sensing monitoring tools, particularly for assessing plant biodiversity.**
 
![Global-Biodiversity-Standard-0.jpg](/uploads/Global_Biodiversity_Standard_0_2bb73c5ee0.jpg)

## Global biodiversity under threat
 
With a quarter of known plant and animal species now on the brink of extinction, biodiversity loss is one of the top five global risks to society over the next ten years, according to the World Economic Forum's Global Risk Report 2023. Synonymous with biological diversity, biodiversity encompasses the taxonomic, functional and structural diversity of living species. Through the ecological services it provides, biodiversity is essential to maintaining the integrity and resilience of ecosystems. 

Among the main indicators of global biodiversity loss, the decline in the extent of forests underlines their essential role as reservoirs of terrestrial biodiversity when they were the native ecosystem in place. They are home to over 80% of the planet's known terrestrial species. In this respect, a better understanding and preservation of forest biodiversity is essential to help halt the onset of the sixth mass extinction.
 
![Global-Biodiversity-Standard-1.jpg](/uploads/Global_Biodiversity_Standard_1_4d330f21cc.jpg)

## The creation of an international standard dedicated to biodiversity
 
### The ambition of the Global Biodiversity Standard

Introduced in 2022, [The Global Biodiversity Standard](https://www.biodiversitystandard.org/) (TGBS) is the only international standard to recognize and encourage the protection, restoration and enhancement of biodiversity. Against a backdrop of increasing numbers of forest creation and restoration projects, this standard aims to develop best practices for creating positive impacts on biodiversity, notably by diversifying tree communities and integrating native species into project design. In the long term, The Global Biodiversity Standard hopes to place biodiversity at the heart of all initiatives that help combat climate change and develop the livelihoods of local communities.
 
### Towards the certification of projects based on the restoration and protection of biodiversity

Based on an international scientific and technical network that includes IUCN & Botanic Garden Conservation International, CIFOR-ICRAF, Royal Botanic Gardens (Kew), Society for Ecological Restoration and Reforest'Action, The Global Biodiversity Standard is currently testing its certification method in real-life conditions, in collaboration with botanical gardens in India, Kenya, Peru, Brazil, Madagascar, Uganda, Malaysia, Jordan and Hong Kong. 

Projects submitted for The Global Biodiversity Standard certification will be assessed against criteria derived from the “10 Golden Rules for Reforestation”. This scientific paper, promulgated by Royal Botanic Gardens (Kew) and Botanic Garden Conservation International, provides guidance on how to ensure that reforestation projects promote biodiversity restoration, carbon sequestration and the creation of socio-economic benefits for local communities. 

Projects certified by The Global Biodiversity Standard must:
- Select appropriate sites to enhance native biodiversity.
- Enhance protection of existing habitats and biodiversity.
- Protect, restore and manage biodiversity in consultation and partnership with local communities and other stakeholders.
- Aim to maximise biodiversity recovery through ecosystem restoration.
- Avoid and reduce invasive or potentially invasive species.
- Prioritise the use of native, threatened and rare species.
- Promote biodiversity and adaptive capacity.
- Implement robust monitoring, evaluation, and adaptive management of biodiversity.
 
 ![Global-Biodiversity-Standard-2.jpg](/uploads/Global_Biodiversity_Standard_2_0ed75a2841.jpg)
 
## Reforest'Action's role in The Global Biodiversity Standard
 
### The contribution to remote sensing of forest biodiversity assessment

As part of The Global Biodiversity Standard's technical and scientific network, Reforest'Action brings its expertise in forest ecosystem restoration and impact measurement to the development of remote sensing monitoring tools. Reforest'Action offers The Global Biodiversity Standard a catalog of tools dedicated to remote sensing measurements. These measurements are carried out both upstream of project implementation, and downstream, as part of project monitoring. 

While tree species diversity has traditionally been assessed through field studies using samples from selected plots, this process is time-consuming and costly for large-scale analysis. Today, remote sensing provides new ways of monitoring vegetation biodiversity, offering the possibility of generating data sets to track environmental changes over the long term. This remote monitoring makes it possible to detect changes taking place within the forest cover, and thus to refine field sampling, in order to prioritize studies within areas that appear to be experiencing more or less positive evolution than others. As a complement to remote sensing, field monitoring remains essential for its accuracy, its ability to validate remote monitoring data and to calibrate the latter by providing real data to refine analyses.
 
### A tool for mapping tree species diversity in canopies

Among the catalog of tools offered by Reforest'Action to The Global Biodiversity Standard, Reforest'Action's Impact Department is collaborating directly with the standard to develop a tool dedicated to mapping the diversity of tree species within canopies. Based on a concept developed by J.-B. Féret and G. P. Asner (2014) and powered by images from Sentinel-2, a satellite in the European Space Agency's Copernicus program, the methodology and tool, re-appropriated by Reforest'Action, enables analysis of the spatial distribution of spectral species, those vegetation zones that include one or more plant species with a similar spectral signature. 

In other words, the tool can be used to assess the diversity of species within a given plot by grouping them into categories known as “spectral species”, based on their physical and biochemical properties (physiological state, water and pigment content, etc.). “Initially, we were looking for a way to measure spatial (within a project area) and temporal (over time) changes in forest stand diversity using remote sensing, in order to better guide sampling during field surveys,” explains Richard Sourbès, Reforest'Action's impact manager. “Based on the method developed by J.-B. Féret and G. P. Asner, we have developed our own tool with innovations that enable us to further refine our remote and field monitoring. While this tool has been used so far mainly in the field of research, Reforest'Action is now applying it for the first time to the operational monitoring of forest restoration projects. This innovative approach is in line with the more general use of remote sensing in the development of our forestry projects - from the design phase through to monitoring.”
 
### A field mission led by Reforest'Action to refine the tool and methodology

During a mission carried out in February 2024 as part of an international workshop organized by The Global Biodiversity Standard, a team from Reforest'Action's Impact Unit travelled to the Brazilian Atlantic Forest to compare estimated remote sensing data with data collected in the field, particularly in terms of tree species diversity in the canopy. “The aim of this mission was to compare the estimate given by satellite imagery with observation in the field, in order to verify their correlation and refine our methodology and tool”, continues Richard Sourbès. “In concrete terms, our experiments in some twenty forest and agroforestry plots demonstrated a strong relationship between the distribution of spectral tree species and that of tree species actually observed in the field.” 

This field mission showed encouraging results in terms of the relevance of monitoring spectral species as a proxy for plant diversity in the canopy. The increasing number of projects monitored using this method will enable us to improve its accuracy in the future, by adapting it to the different stages of maturity and types of forest studied by Reforest'Action. 

Ultimately, this tool should enable us to better control the evolution of our remote sensing projects, so as to optimize our field monitoring missions. It also aims to provide a better understanding of the factors influencing plant diversity and its evolution over time, so as to be able to propose corrective measures as soon as a negative evolution is detected (for example, the presence of an invasive species). Ultimately, this tool will strengthen the adaptive management of our projects and ensure the long-term survival of forest ecosystems.  

![Global-Biodiversity-Standard-4.jpg](/uploads/Global_Biodiversity_Standard_4_e23d45b127.jpg)

_To find out more about the spectral species method developed by Reforest'Action, read our dedicated article: “[Spectral species: an innovative method for studying plant biodiversity from space](https://www.reforestaction.com/en/magazine/spectral-species-monitoring-plant-biodiversity-from-space)”._


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Monitoring biodiversity to better preserve it: Reforest'Action's expertise at the service of The Global Biodiversity Standard

**To improve the monitoring of forest restoration projects, remote sensing can provide complementary indicators and support field surveys. By making it possible to monitor canopy diversity, the spatial distribution of plant species and forest evolution over time, the spectral species method and its associated tools developed by Reforest'Action are invaluable in forest management and restoration projects. They aim to enable forest managers to evolve their practices in order to optimize species diversity, as well as the stability and resilience of the forest ecosystem as a whole.** 

![Spectral-Species-canopy.jpg](/uploads/Spectral_Species_canopy_39e93e4b05.jpg)
 
## Remote sensing applied to the monitoring of vegetation
 
### Analyzing terrestrial ecosystems from space

Space-based remote sensing enables us to observe terrestrial environments using remote data acquisition methods based on the properties of electromagnetic radiation. Satellite sensors can measure the amount of energy (reflectance) reflected or emitted by a surface as a function of the wavelength of the electromagnetic spectrum, and analyze and monitor changes in the surface over time. The total reflectance recorded in each spectral band (blue, green, red, infrared, etc.) forms the object's “spectral signature”. Each surface thus has its own spectral signature, enabling it to be identified on satellite images.
 
### Defining the spectral signature of plant species

Remote sensing makes it possible to establish the spectral signature of plants by analyzing their optical properties in the visible, near-infrared and mid-infrared ranges. These properties depend in particular on the vegetation's cellular structure, as well as its water and pigment content. 
- **Cell structure.** The anatomical structure of leaves plays a significant role in the spectral signature of vegetation at longer wavelengths. Near-infrared radiation passes through the leaf to the cell layer, where oxygen and carbon dioxide are exchanged in the processes of photosynthesis and respiration. In this layer, near-infrared radiation is strongly reflected. It therefore depends directly on leaf anatomy. 
- **Water content.** Leaf water content is also a factor influencing vegetation's spectral signature in the mid-infrared wavelengths. The higher the water content, the lower the reflectance of vegetation. In remote sensing, this wavelength range is used to identify water-stressed vegetation cover.
- **Leaf pigment content.** All plants contain green pigments (chlorophyll), orange pigments (carotenes) and blue-red pigments (anthocyanins). The presence of these leaf pigments (particularly chlorophyll, which is the most abundant) in plants is responsible for their high absorption of visible radiation.

These three elements vary according to season, plant species and life cycle. In other words, the spectral signature of vegetation is not constant. It reflects differences in the structure and characteristics of plant cover. 
 
![Spectral-species-canopy-from-ground.jpg](/uploads/Spectral_species_canopy_from_ground_72dbe3beac.jpg)

## The spectral species method

### From spectral signatures to spectral species: identifying the spatial distribution of plant species

At the scale of a forest plot, remote sensing can identify different spectral signatures, which can be distinguished and attributed to distinct plant species, grouped under categories known as “spectral species”. 

“Through opensource platforms, we have access to Copernicus satellite data, which is revisited every five days or so. We can download the current satellite view of a plot within one of our projects by entering its GPS coordinates,” explains Richard Sourbès, Impact Officer for Reforest'Action. “We then process this data using the Python programming language. On the satellite view, each pixel represents a surface that emits energy in 12 spectral bands. These reflectances in each spectral band are recovered by our software. They make up the spectral signature of the forest surface analyzed. We then try to classify each pixel into groups called spectral species according to the similarity of their signatures, and we thus obtain an estimate of the number of different species present in the canopy.”

This method provides a map of the spatial distribution of spectral species observed in the forest. The map takes the form of a satellite view of the plot, with each pixel color corresponding to a spectral species. 

![Spectral-species-map.jpg](/uploads/Spectral_species_map_ae538870db.jpg)
 
### From the spatial distribution of species to an index of their diversity: monitoring plant biodiversity

This first tool can then be used to calculate diversity indices, in particular the Shannon index. The Shannon index is the most commonly used diversity index in ecology. It is used to calculate species richness and distribution within a forest. In other words, the more numerous and evenly distributed the plant species, the higher the index. 

Reforest'Action uses the Shannon index to determine the specific diversity of spectral species, which is an indicator of the biological (taxonomic) diversity of canopy species. This plant diversity is represented in the form of a heat map, which locates, in warm color, spots of high plant diversity, and in cold color, spots of low plant diversity. It is then possible to follow the evolution of this biodiversity throughout the forest's growth. 

“In concrete terms, the forest stand is re-divided into cells of around 1000 m2, in which the abundance of each of the spectral species present is calculated”, explains Richard Sourbès. “In other words, the Shannon index is calculated by a simple change of scale: going from a 10x10 m pixel to a 33x33 m pixel, we obtain zones containing a greater or lesser diversity of spectral species, enabling us to identify the most diverse areas of the plot studied. Within a cell, the more numerous and evenly distributed the spectral species, the higher the Shannon index.  Conversely, a cell containing a single spectral species will have a Shannon index equal to zero, representing zero species diversity.” 

This mapping is particularly important: it enables field monitoring missions to be steered more effectively, in particular by targeting sampling zones adapted to the results of remote monitoring, and by enabling more precise management recommendations to be formulated. The tool also complements field surveys, which cannot be carried out on all forest stands, as they sometimes extend over dozens or even hundreds of hectares.

![Shannon-Index-Map.jpg](/uploads/Shannon_Index_Map_4dc16676fd.jpg)
 
## Valuable tools for monitoring restoration projects

By making it possible to monitor canopy diversity, the spatial distribution of plant species and forest evolution over time, the spectral species method and its associated tools (spectral species map, Shannon index) are invaluable in forest management and restoration projects. 

Because the data obtained is geo-referenced, it is particularly effective for locating potential invasive species that could threaten the stability of the forest ecosystem, or a lack of species diversity at stand level. They can be used to provide an initial diagnosis of canopy plant biodiversity on a forest scale, to better understand the ecological and environmental factors that favor or hinder plant biodiversity, to establish good practices that lead to high diversity, or to take corrective measures in the opposite case.  

Forest managers can use this data to develop their management practices to optimize species diversity, as well as the stability and resilience of the forest ecosystem as a whole. 

In the medium term, the aim is to be able to calculate the Shannon index for all our projects, in order to monitor the diversity of species represented on the forest plots that have been restored. This index will enable us to measure the impact generated by our projects in terms of plant biodiversity restoration, and will join a range of impact measurement tools currently being developed by Reforest'Action's Innovation & Impact Department.

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Spectral species: an innovative method for monitoring plant biodiversity from space

Projets

Typologies de projets

Agroforesterie

Restauration et création de forêt

Mangrove

Haie Bocagère

Préservation de forêt (REDD+)

Forêt urbaine

Sylvopastoralisme

Régénération naturelle

Actualités du terrain

What are Nature-based Solutions?

Monitoring biodiversity to better preserve it: Reforest'Action's expertise at the service of The Global Biodiversity Standard

Spectral species: an innovative method for monitoring plant biodiversity from space