The white-clawed crayfish stands out as freshwater species for its impressive mix of ancient lineage and ecological impact. It is a living relic with a lineage going back 250 million years, preceding the Triassic period. Its role in the ecosystem is also extraordinary. 

Known to cover a wide spectrum of ecological functions, they are considered a keystone species, ecosystem engineers, flagship species and bioindicators of habitat quality. This aquatic creature clearly has a disproportionate impact on its habitats. 

Read on to learn how its presence helps bring ecological balance in the rivers and streams they inhibit. 

Header photo & below: Bruno_D'Amicis & Carlos Samuel Garcia Bas

River restoration in the Central Apennines

This project fits into the wider efforts to strengthen white-clawed crayfish populations across key catchment areas of the Central Apennines. Specifically, the restoration work done by Rewilding Apennines on the Liri and Verde Rivers. The broader strategy for the region, designed by Rewilding Europe and Rewilding Apennines, is to restore its rivers by returning keystone species and removing dams.

To scale the work already underway in the Liri and Verde Rivers, we are supporting Rewilding Apennines to achieve the following:

Support the crayfish comeback through the establishment of a white-clawed crayfish breeding centre at Pettorano sul Gizio. This is one of three breeding centres set up to restock the Central Apennines watercourses. Our support is covering the setup of the centre’s operations and staffing, monitoring of the animals in the wild and other fieldwork. 

Restore the natural river dynamics through land acquisition. In the area adjacent to the breeding centre, the Giozio river creates a natural meander during times of high water. By slowing water flow and exposing the river bank, the meander creates the perfect conditions for crayfish and hence, would help newly released crayfish to settle. The current landowner, however, intends to reinforce the embankment to stop the river from cutting into his land. The embankment would essentially destroy the suitable crayfish habitat. By purchasing this section of riverfront, we aim to secure this critical crayfish habitat in the long-term.

Promote the crayfish comeback through two community-based initiatives on the theme of ‘Rivers’. The goal is to engage and foster pride in local communities by demonstrating the importance of rivers as strong elements of ecological and cultural heritage. Also, by showcasing the role of crayfish in maintaining healthy rivers and raising awareness of the issues, the events aim to engage the community in the long-term vision of river restoration for the region. They will also provide an opportunity to celebrate the progress made in crayfish comebacks so far. The two events will involve:
- Connecting to local entrepreneurs
- Collecting old stories and recipes linked to rivers from local people
- Co-organising two community-led events

A feasibility study for the release of crayfish in the Central Apennines was carried out by Rewilding Apennines in 2020, which identified streams, including the Gizio River, as having some of the best available habitat for the species with a lower risk of threats than elsewhere. These streams will be used as sites for the young white-clawed crayfish to be reintroduced.

We would like to thank our members for their support in funding this project’s budget of €23,500. The funders for the existing wider project of rewilding rivers in the Central Apennines are Rewilding Europe and Fondation Ensemble.

Poaching and the crayfish plague (Aphanomyces astaci) are the two main threats, which will be addressed in the following ways.

The anti-poaching service, ArciPesca FISA, will oversee monitoring of the areas where juvenile crayfish will be reintroduced. Controls over the areas will be conducted on a weekly basis to ensure poaching is prevented. This measure will be implemented in conjunction with an awareness raising campaign aimed at influencing behavioural change in the long-term. 

To tackle the threat of crayfish plague affecting newly reintroduced crayfish, three separate measures are implemented and will be developed over time.

Communication to the local population: to educate the public on best practices to adopt and prevent the spread of the plague, namely disinfecting materials used when entering rivers. Rewilding Apennines has already produced some specific material for this purpose as part of the EU project LIFE Claw.

The anti-poaching unit operations: which aim to prevent the plague spreading as poachers are known to go between streams.

Trout release monitoring: involving the monitoring of released trout to ensure they have not been contaminated with the crayfish plague. A target communication plan is required to develop this measure.

Mating behaviour was observed at the Pettorano sul Gizio breeding centre. In the months that followed, eggs were detected in the abdomens of half of the female crayfish examined, confirming that reproduction was successful.

The first group of 500 juveniles white-clawed crayfish have been released into the Gizio river. Using an old mill in Pettorano sul Gizio as a hatchery site for female crayfish, allowed for their hatchlings to move independently into the river.

Update October 2025: Releasing crayfish into the Gizio river!

Built with a mechanical yet agile exoskeleton, the white-clawed crayfish is well equipped to traverse fast-flowing streams and navigate rocky waters. As it burrows in search of food and buries to hide away from predators, the crayfish affects sediment buildup on stream and river beds. As such, their movement and feeding behaviour positively influences nutrient cycling and the quality of the habitat, benefiting other aquatic species.

The crayfish is also an important link in the web of interactions as both a predator and prey species. Armed with large imposing white claws, crayfish are omnivores that devour a wide variety of other species and matter. This easy-to-please eater has a diet consisting of macro-invertebrates, small vertebrates and aquatic plants. Feeding on both living and decaying plants and animals, the crayfish is one of nature’s cleaners. Studies show this opportunistic feeder affects the composition of species in the community. For example, by cropping stands of aquatic vegetation with its claws, crayfish control the amounts of plant-living invertebrates. Also, by shredding leaf litter, it supports collector species who mop up the remains of particulate matter.

An abundance of white-clawed crayfish is also vital for predating species. Many different mammals, fish and birds feed on them. Otters, eels and herons are a few examples of animals who predate on crayfish.

Bioindicators or surrogates for water quality 

White-clawed crayfish settle in streams, rivers and ditches by silt and stone beds with clear, well-oxygenated water and free of pollutants. Their preference for more pristine aquatic conditions means they act as a biological indicator of environmental integrity in regions like the Apennines. 

Flagship species are those who hold an appeal to the public for being charismatic and ecologically significant. These roles are usually reserved for attractive mammal species, such as the panda, with invertebrates receiving far less popularity. The crayfish, however, challenges this trend and is considered a flagship species because of its outstanding ecological impact, longevity and cultural importance.

Despite surviving for millions of years, the crayfish is now precariously clinging onto existence in many regions. Between 1999-2009 in Italy, native crayfish populations declined 74%. More recent local surveys in the Abruzzo Region show similar worrying trends. Populations have vanished from the Gizio River and massively decreased in the Verde and Romito Rivers. The 2010 IUCN assessment places the white-clawed crayfish on the Red List of Threatened  Species as Endangered. 

Several serious threats are facing the species, including:

Human Impact: Alterations to catchment areas, canal construction, dams, and water withdrawals negatively impact crayfish habitats.

Climate Change: Aquatic environments are being disrupted by rising temperatures, reduced precipitation, and water acidity.

Poaching: Illegal crayfish capture has increased, particularly across open European borders. 

Invasive Species: Non-native crayfish and fish species introduce diseases and compete with native crayfish. 

In the mid-nineteenth century in Italy, non-native species of crayfish were introduced to watercourses with the intention of restocking local populations. Unbeknown at the time, the non-native species were vectors of what’s known as the ‘crayfish plague’ caused by a fungus called Aphanomyces astaci. Invasive non-native species like the signal crayfish (Pacifastacus leniusculus), although immune to the disease themselves, are hosts for the pathogen. In 1859, the first occurrence of crayfish plague was recorded, wiping out populations of native species, who have no natural resistance. Still today, the disease has a devastating effect on white-clawed crayfish in many regions. With a high mortality rate, often 100%, whole populations are decimated only weeks after the disease enters a waterway.

Targeted reintroductions: Avoiding the plague

In spite of the threats, there have been positive results from conservation initiatives in the UK, France and Italy to restore native populations. As the crayfish plague requires a host, without it the fungus can only survive for a limited period (a few hours to several weeks). If efforts to reinforce populations after an outbreak are targeted at waterways where no alien crayfish exist, the risk of infection is greatly reduced.

Reintroductions should be complemented by measures that address the spread of disease in other ways. As the crayfish plague can be carried via contaminated equipment such as fishing gear, there is a need to raise awareness among local river users of the issue and inform them of best practices, such as disinfecting equipment.

On September 21st 2024, Rewilding Apennines hosted a community gathering to mark the return of the white-clawed crayfish. The open day brought together local entrepreneurs, residents, and nature lovers to share old river stories and celebrate the region’s natural heritage.

It was a truly interdisciplinary experience, blending science, art, music, storytelling, games, and nature walks. The day fostered a deeper connection not only to nature but also among the people themselves - encapsulating the heart of rewilding!

This day was a vibrant celebration of the synergy between nature, culture, and community.

Celebrating the Return of the White-Clawed Crayfish

Adriana Brossmannova, Project Manager @ Mossy Earth

Many people across Europe still remember when the brooks and streams were full of crayfish that have been used as a source of nutrients for people for millennia and therefore this species could act as an ambassador for wider riverine protection efforts.

Hear more background to this intervention with project manager Adriana.

Reintroducing the endangered white-clawed crayfish - PROJECT PODCAST

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Rewilding management plan crayfish comeback.pdf

Supporting the comeback of a freshwater superstar species in the Central Apennines with Rewilding Apennines.

Reintroducing the Endangered White-Clawed Crayfish

Bringing back a piece of the river ecology puzzle in the Central Apennines

The white-clawed crayfish (Austropotamobius pallipes) is somewhat of a superstar of freshwater streams. It claims an impressive collection of ecological accolades as a keystone species, ecosystem engineer, flagship species and bioindicator of habitat quality. This incredibly resilient crustacean has a lineage dating back 250 millions years!

Today, however, white-clawed crayfish are in hot water in the streams of Italy’s Central Apennines and are now an endangered species. This project is designed to bolster populations of white-clawed crayfish across key catchments of the Central Apennines. We are supporting Rewilding Apennines to protect critical riverfront habitat on the Gizio river and to establish a new crayfish breeding centre.

Our Bizarre Approach to Rewilding Sea-Cliffs

Invasive plant removal and community engagement

We are organizing events with local volunteers to help remove the invasive ice plant from the area where it is competing with the rare cliff plants. This is done by manually pulling the plants and removing them from the area. With these events we are aiming to:

stop the invasion before it spreads further and control efforts become unfeasible;

take direct action to restore diverse cliff plant communities (similar efforts have been successful elsewhere);

spread awareness about these species to prevent any damage by park visitors;

encourage dialogue between all the groups involved in protecting, studying and enjoying the area.

Monitoring with a drone and photogrammetry

We will be capturing drone images to survey inaccessible cliffs and ensure we have the evidence needed to guide our conservation actions. We expect the technology will have multiple uses: 

detecting the presence of rare plant species in hard to access locations;

monitoring the distribution of the invasive ice plant and use this data to coordinate removal events; 

monitor the vegetation before and after ice plant removal to check if the vegetation is recovering as expected or if further intervention is needed.

November 2023: Using rope access to remove invasive plants from cliff ecosystems | VLOG

December 2023: Using a high tech drone to map our cliff project for invasive plants | VLOG

Using rope access to remove invasive plants from cliff ecosystems | VLOG

Using a high tech drone to map our cliff project for invasive plants | VLOG

We've described the project itself above, but read on to see why this is so important.

Learn more about how and why we want to protect these plants

For some plants, the cliffs of Cabo Espichel are the ideal refuge from human disturbance and from other species that would outcompete them elsewhere. Two of these plant species have their entire global distribution restricted to this 15 km stretch of coastline and have been listed as endangered in the recently published Red List of Vascular Plants of continental Portugal. 

Convolvulus fernandesii is a species of vine that grows on the cliff faces and at their base, sometimes climbing over other plants and shrubs. It puts out beautiful white flowers in the spring and in the summer its bright green leaves turn yellow. It is extremely rare with the latest estimate putting the total number of mature individuals at 500. 

Euphorbia pedroi is a sub-succulent plant that is adapted to dry conditions which can attain up to 2m in height and more than 2m in width. Its leaves have a very distinct tone of green before they are shed every year during the heat of summer. Although it appears to be more numerous than C. fernandesii, there are only three known subpopulations in the area and it is unclear to what extent these are connected. 

The extreme scarcity of each of these plants makes this a worthwhile mission to ensure their uniqueness remains instead of losing them forever.

Threats that are thought to be affecting both species include:

increases in the frequency and intensity of droughts; 

the spread of the invasive ice plant (Carporboruts edulis).

Take a look at this special vegetation that can only be seen here. The final image shows the spread of the invasive 'ice plant'.

Other than the two narrow endemics, this part of the coast is very rich in plant diversity with about 1400 plant species recorded. Some of these are rare in Portugal and have been identified as a conservation priority by the Portuguese Botanical Society including:         

One serious threat for these rare species is the spread of ice plant (Carpobrous edulis) in the area. This is an invasive succulent plant that forms dense mats which change the soil composition and displace native species that have been evolving together for millennia. It can spread rapidly on dunes and coastal cliffs wiping out entire plant communities. As in other European countries, the species was introduced in Portugal during the 1900s because it was thought to help prevent coastal erosion. It is currently widespread along the Portuguese coast. 

Rock climbers are among the people that spend the most time exploring these cliffs and so are more likely to encounter these rare species. By spreading awareness among the climbing community we want to help reduce the chances that someone will damage these plants due to a lack of knowledge. What’s more, rock climbers are comfortable navigating these hard to access locations so they make ideal volunteers to help us plan and carry out interventions in the area. Having said this, everyone is welcome to join and we hope to get a wide range of people excited about plants and other cliff-dwelling biodiversity!

Using a drone for cliff plant monitoring 

Current methods for monitoring these rare endemic species are very time consuming making it impractical to carry out population surveys with the accuracy and frequency needed to detect population trends and threats. Both species have a very narrow range but their habitat is very hard to access. 

If no other monitoring approach is used, we would have to invest substantial time in continuously monitoring these populations. Accurate population size estimates would require very thorough sampling using abseiling and rock climbing techniques. Other than being logistically complex, this type of survey would be intrusive and could inadvertently disturb the cliff ecosystem. 

To address this, we are using a drone to capture high resolution images which can later be processed to detect where the individuals of each species are present. After being validated and refined, we hope this approach will provide a reproducible and cost effective way to monitor the abundance and distribution of these rare species. 

We also aim to use the drone and photogrammetry software to create orthophotomaps of the areas where C. edulis is to be removed. The resulting maps will help to plan the removal events but, more importantly, they provide a baseline scenario for monitoring the impact of this intervention on native vegetation. By creating the same maps every year, we hope to capture the process of recolonization by native vegetation. These surveys may demonstrate the success of the intervention or a failure of native plants to recolonize the area which would suggest that assisted revegetation may be appropriate. Finally, we expect the maps will prove useful as a way of identifying C. edulis resprouts that could be missed otherwise.

The partnerships making this project possible

We are getting all kinds of partners together for this project. The local rock climbing community and the cavers from NECA (@neca.espeleologia.arrabida on Instagram) are contributing as volunteers with their local knowledge, sweat and hard work in our invasive plant removal events. 

Pix4D, a drone mapping software company, has kindly offered to sponsor our use of their software for this and other Mossy Earth projects. This is part of their ambition of using their technology to support nature conservation and restoration projects. 

The Portuguese Botanical Society is contributing with crucial plant science expertise and the local park authorities (ICNF) are helping ensure our efforts fit into the broader conservation strategy for this protected area. Finally, we have the support of the local municipality (Camara Municipal de Sesimbra) for logistical issues and to coordinate with their ongoing efforts to conserve the area's unique biodiversity. 

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Management_plan_cliff_plants.pdf

To help save plant species that exist nowhere else on earth, we are working with volunteers from the rock climbing community to remove an invasive plant from sea cliffs in Portugal.

Saving Rare Sea Cliff Plants

On a stunning 15 km stretch of Portuguese coast two special cliff plants found nowhere else on earth are facing extinction. The main threat comes from a dominating invasive species carpeting the cliff called the ‘ice plant’. Access to the sheer cliff faces poses a challenge for their conservation. This is why we’ve gathered local rock climbers and cavers, passionate about local biodiversity, to remove the invasive ice plant. We’re also using drone technology to document changes to the vegetation. Protecting these precious plants not only reduces biodiversity loss but treasures nature in all its glorious forms.

We’re chainsawing healthy trees into rivers - here's why

Riparian Ecosystems - supporting an array of aquatic life

Rich riparian ecosystems host a complexity of biodiversity and support many natural processes and functions. In addition to providing habitats for insects, fish and other species drawn to these vibrant water sources, they play a role in mitigating flooding and pollution. Natural riverside ‘buffer’ zones, where areas like swales and small wetlands form, can reduce peak flows, capture pollutants from agricultural runoff and promote natural processing of nutrients. 

Another vital component of healthy, dynamic riverine ecosystems is tree cover. By providing shade, trees help control rising water temperatures, hence minimising the thermal stress on aquatic life which can be fatal for fish species like the Atlantic salmon. Tree root systems also prevent riverbank erosion and are used by fish to shelter from predators. Further to this, riparian trees help reduce airborne spray drift of agrochemicals and add woody debris and leaf litter into the system that creates habitats, more dynamic water flow and aids pollutant removal. That being said, too much tree cover blocks the light needed for photosynthesis for other important aquatic plants. This can adversely affect species reliant on a diversity of vegetation. The ideal balance between shade and open areas is generally agreed at 60% shading of the channel with 40% receiving dappled sunlight.

Situated within the Bristol Avon catchment, the River Chew has fragments of lush wetlands and ancient woodlands that provide vital wildlife corridors for insects, birds, bats and mammals. The river also supports migratory fish after their arduous migrations out to sea when they return to spawn in freshwater habitat. Among the species found to be using the tributaries through eDNA testing is the European eel, sea trout, brook lamprey and the iconic Atlantic salmon, all of which appear on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. 

Maintaining healthy populations of these species has a positive cascading effect across freshwater and marine ecosystems. Take the Atlantic salmon for example, it’s a prey species to many animals along its migration and brings nutrients from the ocean upstream to freshwater environments through excretion, spawning and decay. Current challenges of habitat degradation and obstruction in the Chew catchment are jeopardising these species’ life cycles, risking the balance of interactions that would result from population declines.

Within the Bristol Avon catchment only 12% of water bodies have been classified as having good ecological status. Reasons attributed to the poor conditions include physical alterations to watercourses and elevated levels of phosphate and nitrate. There are other factors considered to also affect this, such as fine sediment loads from land use, pesticides, pharmaceutical chemicals and contaminated road runoff. Subsequently, fish populations are threatened by the pressures created by poor water quality and pollution as well as physical barriers like weirs that prevent them reaching spawning sites.

One of the main drivers of degradation to these precious riparian ecosystems, and in particular for the River Chew catchment, comes from adjacent land use. Alongside many areas of the stream, surrounding land is used for pasture and crop production. In some areas, there are no boundaries as the agricultural land squeezes up close to the water’s edge. This leads to agricultural runoff and silting which smothers the gravels that fish use for spawning and can impact other aquatic life within the freshwater. As access for livestock is unrestricted along some of the riparian zones, vegetation and banks have been disrupted by trampling and excretion. Furthermore, there are areas of overgrown vegetation which prevent macrophytes (aquatic weeds that help the oxidation of water) from colonising. 

The current state of the riparian habitat leaves great potential to restore and connect areas that will not only help struggling species populations but also enhance the ecosystem’s overall resilience. 

The overall objective of this project is to restore sections of the Candlestick Brook and Bathford Brook to improve the ecological health and riparian habitat connectivity of these two key fish spawning sites. Both brooks flow into the River Chew in the Bristol Avon catchment.

The first stage of the project involves conducting habitat and fish spawning surveys and developing landowner engagement. These actions intend to inform the required restoration works and reduce landowners’ impact on the riparian areas. The outcomes of this stage could lead to a combination of the following interventions being implemented by BART, working in partnership with relevant landowners.

Livestock management: such as livestock fencing and creating buffer strips to reduce encroachment along the brooks.

Installation of woody debris into the watercourse: to improve the diversity of waterflow, with the potential to create new wetland areas, in addition to providing habitats and spawning sites for wild migratory fish.

Riparian tree management: designed to achieve more optimal light conditions (targeting a 60:40 ratio) by thinning wooded canopy. A reduction in shading can facilitate macrophyte growth and help create clean riverbed gravels ideal for fish spawning.

Riparian tree planting: to increase shade where the brooks are overexposed to natural light, helping to regulate water temperatures. Additionally, tree planting can eventually help stabilise banks and input woody materials into the watercourse, needed for the development of invertebrate populations.

The main desired outcomes these interventions hope to achieve are:

Improved habitat for migratory fish species, including Atlantic salmon, brook lamprey and European eel

Increased areas for pollinators via establishment of marginal vegetation and macrophytes

Enhanced biodiversity within a region with a growing population with a significant history relating to its river.

Funds raised through the Mossy Earth Membership are covering the initial costs of the project which include equipment and contractor fees for the habitat restoration works, tree management and livestock management as well as staffing, travel and permits costs.

The wider objective of this project is to establish a flagship ‘spawning tributary’ restoration to stimulate public interest and contribute to the Bristol Avon Fish Recovery Strategy. Produced by the Bristol Avon Catchment Partnership, this is a guide for collective action to sustain fish populations by embedding the value of rivers in decision-making across spatial planning, public health and economic development, with an ultimate aim of generating learning and information sharing across stakeholder groups. To add to this, the Bristol Avon Catchment Partnership also seeks to improve access for fish moving into and within the River Chew by working in partnership with local authorities, water companies, the Environment Agency and other NGOs. This focuses on improving fish passage by removing barriers to fish movement, such as weir removal and installing fish passes where removal is not feasible.

Freshwater ecologists from BART will conduct the habitat and fish spawning surveys, including salmonid spawning surveys and redd counts. The River Corridor Survey will be done at the start of the project and repeated 1-2 years after the project’s completion. 

Various other methods of monitoring will be applied, including site visits to check on the health of new trees, capturing ‘before and after’ imagery of the habitat and on-site discussions with landowners. Long-term monitoring will involve the community in the way of citizen science where volunteers will monitor riverflies as indicators of water and habitat quality.

Areas of the watercourse have a variety of vegetation while others are bare and exposed to livestock.

Different views of River Chew's riparian zone 

Key to achieving this project’s main aims is building landowner engagement. BART has already established good relationships with several landowners and is developing further support for the project. By promoting the benefits of establishing riparian corridors, BART hopes to encourage more landowners to agree on opportunities to reduce impact on the land through the proposed interventions. This project will be used as an example of best practice to promote more widespread adoption from other landowners in the future.

We are excited about working towards this project’s outcomes in the hope our efforts will create better ecological conditions and bring more life to the river.

There is a significant sediment issue in the catchment which greatly reduces water quality and decreases habitat quality by smothering gravel riffles in silt. One of the main pollution pathways into streams and rivers are roads and track systems. BART is creating 7 cross drains across the tracks to divert the runoff of the tracks and into the neighbouring vegetation.

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River Chew Spawning Tributary Restoration Management Plan.docx.pdf

Learn how we aim to restore riparian habitats and improve watercourses of two key fish spawning tributaries in the Bristol Avon catchment in partnership with BART. 

Restoring Fish Spawning Tributaries and Riparian Habitat

Improving connectivity and habitats in the River Chew catchment

The River Chew is a scenic watercourse that forms part of the Bristol Avon network of rivers, streams and lakes in the British countryside. Along stretches of the river, trees and vegetation provide food, shelter and spawning grounds for important migratory fish and invertebrates, including the protected Atlantic salmon. Where there is sufficient shade, trees help improve water temperatures, sediment levels and the riverbank. However, sections of the River Chew don’t have this delicate balance of vegetation cover and have been degraded by surrounding land use. Partnering with BART (Bristol Avon River Trust), we are focusing on river habitat restoration, riparian tree management, landowner engagement and habitat and fish spawning surveys to improve two key fish spawning tributaries.

Iberá - the shimmering waters of Argentina

The expansive wetland habitats of Iberá are famed for conjuring up picturesque scenes of entrancing wilderness. The land of ‘shimmering waters’ (‘iberá’ translated from Guaraní) also holds significant value as an area of special conservation interest. It’s situated in the Corrientes Province of northeastern Argentina in the heart of a subtropical plain encompassed by Paraná Atlantic forest, Chaco forest, open grasslands and shrublands. 

Within the park’s 758,000 hectares (comprising the Iberá Provincial Park of 600,000 ha and Iberá National Park, of 158,000 hectares) are some of the largest wetlands in South America. An estimated 4,000 species of flora and fauna contribute to the productive ecosystems in the diversity of marshlands, grasslands, forests and open water habitats. Of the many reptiles, mammals and birds, there are caimans, rheas, capybaras, many species of deer, armadillos, foxes, herons, storks and birds of prey. Endangered species such as the black-and-white monjita, the pampas deer, marsh deer, maned wolf, crowned eagle, and a large diversity of Paraná fish also take refuge in Iberá.

In the last century, a host of species in the Corrientes Province have succumbed to human pressures, either slipping entirely into extinction or greatly decreasing in numbers. 

Habitat destruction driven by factors such as agricultural expansion, and hunting, in which animals were killed for their feathers and fur, led to mass losses of wildlife. Jaguars, giant river otters, tapirs, collared and white-lipped peccaries, giant anteaters, bare faced curassows, red-and-green macaws, and the glaucous macaws went extinct in the wild on a regional, national and sometimes global level. While ocelots, along with pampas deers, maned wolves, lowland pacas, and red-legged seriemas suffered huge declines.

Since 2007, Rewilding Argentina (previously operated as CLT-Argentina, an NGO initiated by Doug and Kris Tompkins) has been working to reverse the extinction crisis, restore ecological health and create new economic opportunities in Iberá.

Iberá offers the right conditions to undertake ambitious multi-species reintroductions owing to its vastness and quality of habitats. Within Iberá - the nation’s largest protected area - the threats to animals are being managed. Nature-based tourism is the main economic activity, enticing nature enthusiasts from around the globe to come and observe animals of all kinds in spectacular settings. Surrounding the park, there has been a shift from cattle ranching and forestry towards nature-friendly land use. Members from the surrounding 10 communities are now trained as wildlife guides and work in ecotourism.

Some of the impressive rewilding work already undertaken by Rewilding Argentina has focused on recovering locally extinct or struggling species. In 2021, jaguars returned to the park after being absent for 70 years in a reintroduction project. Corrientes went from having no jaguars to being the province of the Argentinean Chaco with the highest number of this wild cat. Building on this experience and with the help of Mossy Earth funding, Rewilding Argentina has now set out to bring back another important predator - the ocelot.

The ocelot (Leopardus pardalis) is classed as a medium-sized wild cat, but sits only behind the jaguar and puma as Latin America’s third largest feline. With its beautifully patterned coat, the ocelot has an eye-catching appearance for us, but its dark rosettes and spots allow it to camouflage and blend into its habitat. Combined with a slender and agile build, it is well equipped to seek out its prey, which includes small birds, rodents and reptiles among medium-sized mammals, such as brown brocket deer and young capybaras. They are skilful tree climbers and patient hunters, known to wait 30-60 minutes before pouncing on their prey. Ocelots are adaptable species suited to numerous habitats from dry mountains, humid jungles, open grasslands, wetlands and deserts.

Ocelots are mesopredators (medium-sized predators) who play a crucial role in maintaining two important ecological relationships: predation and competition. By hunting prey and competing with or directly preying on other medium-sized predators like foxes, they regulate the abundance of these species, which has a cascading effect on the ecosystem and populations of other species. For instance, the establishment of a healthy ocelot population in Iberá will likely have a positive effect on some threatened species of grassland birds that are currently under high predation pressure from foxes.

The presence of predators also affects behavioural patterns of their prey. In Iberá, one of the expected impacts of an ocelot comeback relates to the grazing behaviour of capybaras. Faced with the threat of predation by ocelots, we can expect that capybaras will spend less time grazing and more time avoiding the predators, which will decrease grazing pressure in a given area and lead to more environmental heterogeneity. Rewilding Argentina is partnering with researchers and universities to study the long-term ecological impact of species reintroduction in Iberá.

Historically, ocelots were widely distributed with a range stretching from central-northern Argentina to the southern United States. Appearing in early civilizations through the artwork and mythology of the Aztec and Inca eras, ocelots were respected for their prowess as hunters in the animal kingdom. In more modern times, humans’ can be viewed more as ‘eradicators’ in this relationship. A booming fur trade in the 1960-70s for ocelot hides compounded by an accelerated rate of habitat destruction, caused ocelot populations to severely decline or go extinct in much of their original range. Habitat loss is the main threat that exists today due to deforestation and other human driven factors, such as agricultural intensification.

Ocelots are classified as vulnerable to extinction in Argentina. Small remaining populations have sought refuge in the humid forests and mountains of the north. In the Corrientes Province, only a few individuals have been recorded, being restricted to the extreme northeast of the province. In Iberá, the last sighting came from a camera trap of a single male ocelot in 2015. Without an effort to reintroduce the species, ocelots are highly unlikely to reoccupy Iberá naturally.

Mossy Earth is proud to be supporting Rewilding Argentina with an ocelot reintroduction project at Iberá park to recover the species. Through funds made available by our members, we are supporting one year of this ambitious 6-year project, the first ever ocelot reintroduction project worldwide.

This component of the project requires the diligent work of the Rewilding Argentina team, which incorporates experts and trained professional, to carry out the following activities:

Incorporate a minimum of four ocelots into the project (from the project total of 15 ocelots): ocelots to be donated by wildlife rescue centres and zoos in Argentina, Brazil, and Paraguay and translocated to Rewilding Argentina’s quarantine centre.


Ensure the animals meet the necessary sanitary standards for eventual release: involving health checks, analysing biological samples, managing any treatable diseases and verifying the animals are disease-free.


Conduct the rehabilitation of animals within pre-release enclosures after the quarantine period ends, in preparation for their release: through placing the animals in pre-release enclosures to replicate their natural environment; incorporating live prey into their diets until the animals exclusively hunt for food; and facilitating mating encounters to produce offspring. The possibility of releasing females with their cubs will be evaluated. Individuals that show strong breeding capabilities during their time in captivity will be released to bolster the number of births and improve the self-sufficiency of new populations. 


Release a minimum of 4 individuals into Iberá park: between 4 to 6 individuals from the pre-release pens during two release periods during the year.


Monitor the adaptation of the animals post-release: the ocelots are to be fitted with GPS telemetry for tracking, which will monitor and assess their movement, acclimatisation and hunting ability. The animals will be supplemented with food if necessary and retrieved/assisted in the case they fail to hunt or require medical care. Long-term monitoring will continue to ensure animals’ survival and register reproductive events post-release.

To reach a self-sustaining population of ocelots in the park, the genetic variability of the reintroduced animals will be studied 4 years following the project’s completion. Based on the results, further interventions will be carried out if needed to improve genetic diversity.

There are potential risks of ocelot reintroductions for which this project has mitigation measures in place. In the case of the ocelots dispersing into populated areas, there is a possible threat to livestock and poultry. To address this, proactive measures include engaging with farmers prior to the release and promoting abundant wild prey for the ocelots. Reactive measures will involve adjusting husbandry practices and implementing night hours enclosures for livestock and poultry. 

Within Iberá park’s 758,000 hectares, the threats to the ocelots are either absent or minimal. Poaching is absent, extractive activities are almost non-existent and there are no permanent residents living in the park.

Taking a comprehensive approach to preparing for and adapting to post-release scenarios is essential in promoting a peaceful coexistence. The goal is to minimise risks for the local community, protect domestic animals and prevent conflicts.

Reintroduction programs are not a common conservation/rewilding strategy in South America. As a consequence, the supporting administrative processes are often cumbersome or entirely lacking. This represents a hurdle for this project to overcome but in doing so, it aims to pave the way for future species reintroductions on the continent. 

The experience and knowledge generated through this project will be used to improve reintroduction techniques for the ocelot. Results and methodologies will be published in specific bulletins, similar to those used by the IUCN. Additionally, a reintroduction protocol for ocelots will be drafted to be used by governments and organisations in Argentina or other countries interested in the species recovery. There will be an extended invitation to the field to learn from the project.

Part of this project’s vision is for Iberá to become a source of species to launch reintroductions elsewhere in the world. Already, there is expressed interest in reintroductions in Texas, US.

The comeback of one of Argentina’s most iconic cats presents an opportunity to enhance the appeal of Iberá as a unique wilderness destination for tourists. By communicating and documenting the arrival, release and adaptation of the ocelots, Rewilding Argentina and Mossy Earth aim to generate more interest among visitors and spread awareness of their role in a functioning, complete ecosystem.

The first two ocelots released into the wild in December 2023 were Tomi and Luna. Below are some images of them exploring their new home and a new arrival named Lila from Paraguay settling into the quarantine facilities in Argentina.

Project manager, Adriana, gives more background on this project with Rewilding Argentina.

We're supporting ocelot reintroductions in the wetlands of Iberá, Argentina - PROJECT DISCUSSION

Mossy Earth-Ocelot Reintroduction Project Final Report 2025.pdf

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Edited_Rewilding management plan templan v.2.pdf

We are supporting Rewilding Argentina in bringing back one of the great cats of the Americas to Iberá park in a pioneering reintroduction project.

Ocelot Reintroductions in Iberá

Supporting the recovery of an iconic predator in Argentina

Ocelots are one of the great wild cats of the Americas. These adaptable felines were once widespread across the continent, including the subtropical plains of northern Argentina. During the twentieth century, ocelot populations declined as they were hunted for fur and large swathes of habitat were destroyed. Today, the ocelot is virtually extinct across its original range in Argentina. Consequently, wild areas like the vast wetlands of Iberá shimmer less without this charismatic cat, which plays a crucial role in regulating other species. We are supporting Rewilding Argentina in a pioneering initiative to recover this species in Iberá - the first ocelot reintroduction of this scale worldwide.

We're Bringing Back Europe's Lost Butterfly Meadows

Butterflies and moths are part of the most diverse group of organisms in the animal kingdom - insects. Up to two thirds of our planet’s 1.5 million recorded animal species are insects with butterflies having their share of the diversity. There are 482 species of butterflies in Europe of which almost a third are endemic. But bugs are in trouble. Their numbers are declining globally at an unprecedented rate, butterflies being no exception. A third of butterfly populations are stated on the European Red List as in decline since 2009. To preserve these beautiful species and their rich biodiversity, we need to look at the strong bond between butterflies and their host plants.

Specialist Species: butterflies & host plant relationships

Some species of butterfly are monophagous meaning they rely solely on a certain plant species to lay their eggs for their larvae to feed on. Therefore, to create conditions for these butterflies, we must consider the conditions their host plants thrive in. For host plants of many European butterflies the optimal conditions are often maintained by grazing animals. This is because they require either short vegetation cover or they grow in places where the soil has been disturbed by animal hooves. 

The relationships between butterflies and their host plants can involve intricate and fascinating interactions. In some cases, butterflies will lay their eggs not only on a particular plant species, but also exclusively during certain stages of the plant’s growth. Take the Danube clouded yellow (Colias myrmidone) butterfly for example. The female lays its eggs individually on the tops of young shoots of plants belonging to the genus Chamaecytisus. The female searches for the fresh nutritious shoots because this is what her caterpillars feed on once they hatch. However, the host plant needs to be grazed regularly. If not grazed, the plants will go into a vegetative state and will stop producing the young shoots necessary for the caterpillar’s development. 

This intricate interaction between the butterfly and its host plant means that many butterfly species are very sensitive to changes in their environment. The Danube clouded yellow, for instance, has gone extinct from many countries of Western and Central Europe because of the changes in agriculture during the 21st century. The remaining populations are small and sparsely scattered in Slovakia, Poland and Romania, making it one of the most threatened of Europe’s butterflies. 

Shaping Europe’s Grasslands Through Grazing

Evidence from pollen analysis and the complex plant and animal communities found on European grasslands today suggests that the Post-Glacial landscapes of Central and Western Europe consisted of a mosaic of closed forests, open woodlands and grasslands. Arid conditions and the presence of megafauna, that roamed freely and grazed, were key factors in creating conditions for grassland communities to develop. Ancient species like bison, aurochs (wild ox) and tarpan (wild horse) were some of the natural grazers who would have grazed, trampled and disturbed European landscapes for millenia, maintaining a diversity of grassland habitats and the conditions for grassland species to thrive in. 

With the disappearance of grazing megafauna, traditional animal husbandry and grazing practices took over this function to some extent. Compensating for the loss of megafauna in this way allowed grassland species to survive. Today, many of the remaining biodiverse areas we see in Europe, particularly semi-natural grasslands, are heavily influenced by human activity. Coming as a positive side-effect of traditional farming practices, the most diverse grassland habitats we find in Europe today were maintained or created by grazing of domesticated livestock. However, several factors, including land abandonment and the shift towards intensive farming practices, has led to the degradation of many important habitats. The absence of grazing animals has impacted species within both grasslands and woodlands, who rely on open grazed areas, clearings, grass patches or open woodland margins. As such, the main threats to European butterflies are habitat loss and habitat fragmentation driven by changes in land use relating to:

Intensification of agricultural production: increased demand leading to habitats such as meadows being turned into cropland.

Abandonment of traditional low intensity (extensive) grazing and mowing for hay. A myriad of complex social and economical factors are believed to be causing widespread land abandonment in Europe. One of these influences comes from increased agricultural intensification that has moved farming from marginal areas using traditional farming to more productive lands elsewhere. Ceasing traditional farming practices in these marginal areas has led to the succession by shrubs and trees which gradually outcompete the flowering plants and grassess required by insects.

Use of insecticides: studies shows these pesticides are having harmful side-effects on butterfly and other insect populations.

The following issues are additional factors affecting butterfly numbers in Slovakia and the project area: misdirected subsidies for intensive large-scale mowing, especially mulching of meadows in the wrong time of the year; and past afforestation initiatives using pine trees.

Beckovske Skalice: a refuge for butterflies

Beckovske Skalice in West Slovakia is a hilly mosaic of different grassland and open woodland habitats situated in the middle of a river floodplain between two mountain ranges. Surrounded by urbanised and agricultural land, this place functions as a micro-reserve for pollinating butterflies, moths, bees and their host plants. The importance of the area for biodiversity is marked by its designation as a Natura 2000 protection site. The site was designated for the protection of rare moth and butterfly species, Jersey Tiger (Callimorpha quadripunctaria), Orange eggar (Eriogaster catax) and Danube clouded yellow (Colias myrmidone). 70 plus species have been recorded there with potentially just as many moths. Although recent monitoring didn’t detect the Danube clouded yellow nor the Orange eggar, they are believed to be present, just in very low numbers. The Danube clouded yellow is of particular concern with recent extinctions in Germany, Austria, Hungary and the Czech Republic, making it one of the most endangered butterfly species in Central Europe. In Slovakia, this species appears very sporadically, indicating it’s on the brink of extinction. Unfortunately, this trend is playing out for insects in general. Recent studies have flagged rapid declines in insect biodiversity and abundance across Central Europe.

Used in the past as a grazing site, the current state of Beckovske Skalice is unfavourable for both butterflies and moths as the overgrowth of woody plants is crowding out the open areas with butterfly host plants. Should the area be left to continue this progression, the remaining available habitat for butterflies, moths and other insects would ultimately disappear. 

The main objective of this project is to improve and expand the shrinking butterfly and moth habitats at Beckovske Skalice. To achieve this, we are collaborating with BROZ to recreate a mosaic of grassland and open woodland areas so insect host plants can flourish. This will involve adopting conservation grazing using husbandry animals as well as removing overgrown shrubs and trees.

Many of the threatened butterfly species at Beckovske Skalice are specialists that either feed exclusively on one plant (monophagous) or a few plants (oligophagous). These plants include those from the genus Thymus, aromatic perennial herbaceous plants, and from Chamaecytisus or Gentiana, both groups of flowering plants. The former are known to prefer low vegetation cover shaped by grazing, while the latter groups grow well in places where the soil has been disturbed by trampling. With this in mind, a few different grazing herbivores will be used for their differing grazing styles. Goats have been chosen because of their preference for shrubs and ability to access rocky terrain. Sheep, who graze low on the ground will benefit the habitat by keeping ground vegetation short in height, catering to some host plants. Browsers such as donkeys will also be added to keep succession by woody vegetation at bay.

It is not enough to reinstate grazing herbivores then to stand back. Due to the relatively small area, we will need to monitor the densities of vegetation and butterfly populations, and if needed carefully adapt the grazing pressure should there be signs of overgrazing or undergrazing. For this task, BROZ will draw on expert botanists and entomologists as well as from their experience of similar interventions in the region. For more details, see Monitoring below.

The other component of this project addresses the overgrowth of shrubs, especially the artificially introduced pines and non native acacia on the site. Without the grazers to keep the balance, these have gradually spread, consuming space and light needed by the butterfly host plants. Work has already begun to strip back some of this with 11ha (27 acres) being cleared last winter. However, there are still areas of open dry meadow and open oak woodlands that have to be cleared through laborious and careful work. Under the supervision of an expert the unwanted vegetation will be selectively removed while leaving the native trees such as oaks or chesnuts. Once the remaining overgrown areas of 6ha are cleared, the grazing area will total 17ha. 

Our goal with this intervention is to not only save struggling butterfly and moth populations but in doing so restore one of Europe’s most threatened habitats - oak wood pastures and dry orchid meadows. By creating more suitable habitat conditions, other pollinating insects such as solitary bees, bumblebees, grasshoppers and beetles also stand to benefit.

The project costs are shared between the project partners, with BROZ covering staff, travel and husbandry animal costs, while funds from the Mossy Earth membership will pay for materials and infrastructure for the grazing and the expenses for removing the overgrowth.

Expert botanists and entomologists will carry out the project’s monitoring to track changes in species abundance and composition. This will happen on a yearly basis, with reports to be published in 2026 and 2029. Following these, monitoring will be done every 3 years as a part of the regular monitoring of habitats and species of European importance conducted by the State Nature Conservancy.

To support butterfly populations in the long term, conservation grazing needs to be sustained. For this, the area is part of the LIFE Metamorphosis project and the After Life pledge. This agreement ensures the area will be managed for grazing until at least 2059. Following this period, grazing will depend on the availability of funding and agreements with local stakeholders.

For me this project stands out because it shifts the paradigm. It shows how people can not only coexist with nature but also that our presence can actually benefit nature.

This project expects to engage several stakeholders in a positive way. Firstly, the changes to the project site will benefit the landowner, improving the state of the land after years of abandonment. Secondly, a local farmer and restaurant owner will also use a part of the area to graze his animals. The cottage restaurant serves a selection of specialities made from sheep cheese produced locally, which could draw in more custom. Finally, there is the possibility of delivering a small boost to local tourism as a tourist trail runs through the site. An attractive butterfly meadow will no doubt add to the touristic appeal of the area. There is a local tourist club association that organises events and is willing to cooperate and create new trails. This aims to prevent crossings with grazing fences and to act as a source of information and inspiration on butterfly and insect species during excursions.

Broadly speaking, rewilding is often seen as an approach to conservation that removes the pressure of people on the land. In the case of European butterflies, the species and their habitats have continued to evolve in cultivated landscapes for thousands of years. Instead of removing humans from the picture completely, it is in fact, vital that our carefully managed influence on these semi-natural habitats continues in order to sustain these precious habitats and species. Our vision for this project is to reinstate human management of the land for a positive outcome for biodiversity.

Below is a selection of the stunning species recorded in the project area.

The Beautiful Butterflies of Beckovske Skalice

Mossy Earth project manager, Adriana, meets with Mossy Earth Community Manager Meija to discuss the project's objectives and to give more background on why it's needed. Also, check out our Transparency Dashboard where you can see all the species of butterfly we are trying to protect.

Rewilding

How it works

Reintroducing the Endangered White-Clawed Crayfish

Saving Rare Sea Cliff Plants

Restoring Fish Spawning Tributaries and Riparian Habitat

Ocelot Reintroductions in Iberá

Restoring Rare Butterfly Habitats

Translocating European Ground Squirrels

Rewilding:

An introduction