Property comes under management of Rewilding Portugal

Various clean ups managed by Rewilding Portugal

Reptile and amphibian surveys and drone mapping conducted.

Conduct a bird survey and drone mapping to give us an indication on which bird species are present and to provide a visual update on how the area has changed since the earth movements.

Spring aquatic plant surveys take place. Results published during the summer of 2024.

We’ve created a new lake and the results are fascinating

Since mining came to a halt over a decade ago at Paul de Toirões, the area has gradually evolved into numerous water environments including lakes, ponds and marshes. These habitats are now filled with aquatic and riparian vegetation, such as reeds and rushes, where tin, titanium and sand were once extracted.

Paul de Toirões is one of the key areas managed by Rewilding Portugal as part of their landscape-scale rewilding ambitions in the Greater Côa Valley and is within the wider Natura 2000 network of protected wild areas on the Iberian Peninsula. Being afforded the necessary space and time, Paul de Toirões is an example of how degraded land can be reclaimed and rebuilt by nature.

Since the site was abandoned, it has already attracted a wonderful mix of wildlife such as the European pond turtle, marsh harrier and the black stork who feed and seek sanctuary there. It is a hot spot for birds in the region - 112 species of birds have been registered in Paul de Toirões to date. This includes resident species, summer visitors, like the black stork or the Eurasian hobby (a small, slim falcon), and species that use these habitats to rest and feed during migration, like spoonbills, wintering grey herons and many other important species. Without these habitats, the migratory birds would have no other similar resting grounds within a 100-mile radius.

Mammals, particularly bats, small mammals and otters as well as amphibians and reptiles stand to benefit from habitat restoration at Paul de Toirões too. 

Below is a sample of the wildlife found in the area:

Black stork: Least Concern (IUCN), Vulnerable (Nationally)

Marsh harrier: Least Concern (IUCN), Vulnerable (Nationally)

Common sandpiper: Least Concern (IUCN), Vulnerable (Nationally)

Green sandpiper: Least Concern (IUCN), Near Threatened (Nationally)

Common Reed-warbler: Least Concern (IUCN), Near Threatened (Nationally)

Iberian ribbed newt: Near Threatened (IUCN), Least Concern (Nationally)

Iberian midwife toad: Near Threatened (IUCN), Least Concern (Nationally)

Iberian terrapin: Vulnerable (IUCN), Least Concern (Nationally)

European pond turtle: Near Threatened (IUCN), Endangered (Nationally)

The restoration of habitats at Paul de Toirões has the potential to secure a future refuge for a vibrant array of species, not only those that are found here now but others that may come to colonise the area as it evolves. With severe droughts predicted to become more common in the coming decades, it is all the more important for us to focus on wetlands of this nature, especially since they are so rare in the region. The site is also well suited to showcase the potential of rewilding principles, since we believe it has the potential to evolve into an amazing natural area if given a helping hand.   

We are partnering with Rewilding Portugal to enlarge and diversify the wetland habitats of Paul de Toirões by carrying out targeted earthworks to change the way water moves and accumulates in the landscape. 

By smoothening the margins of some ponds, we will increase their area and also create a more gradual change in water depth and environmental conditions. In other cases, partially blocking the artificial water passages (made when the mine was active) will increase the area that gets flooded or create the conditions for Mediterranean temporary ponds to develop. These ponds, that dry out in the summer, are very special because some species have evolved to take advantage of their ephemeral nature. For example, for amphibians to lay their eggs in relative safety. In a few locations where it is feasible, we will build cascades to improve the oxygenation of the water and further increase the habitat complexity.

The main expenses for this project, which will be covered by the support of Mossy Earth members, are those associated with the machinery as well as the labour required to plan, carry out and monitor these interventions in the field. 

The overall approach for this project is to make concrete interventions that will facilitate the natural recovery of the area and then to step back and let the ecosystem processes take their own course.  Having said this, we expect the work to lead to a range of positive outcomes for biodiversity in the region including: 

An increased abundance of nesting and wintering birds.

Boosting the populations of amphibians, reptiles, mollusks and arthropods in the lakes and ponds.

Improving water retention and the ecosystem's ability to capture CO2, increasing landscape resilience to climate change. 

See the video below for drone views of the one of the water bodies prior to and following earth works from October 2022 and April 2024.

Before & After - Rewilding a Former Mining Site

Amongst the diversity of aquatic habitats at Paúl de Toirões different freshwater plants will establish, for which it’s important to know where and what plant species are present. This is why aquatic plant surveys are being incorporated into this project's plan with the aim of registering and mapping  the area's aquatic plants. This information will be used to aid further decisions to inform potential interventions like water management and introduction of species.

Two surveys are planned for autumn 2023 and spring 2024. See the results of the autumn 2023 survey here. For more details of the aquatic plant surveys, download the management plan.

The Broader Context of Rewilding Efforts in the Area

The Scaling up Rewilding in the Greater Côa Valley project is being led by Rewilding Europe and focuses on the Greater Côa Valley. Partners are working to reinforce a 120,000-hectare wildlife corridor to improve connectivity in the landscape between the Malcata mountain range and the Douro Valley. This project will contribute directly towards achieving that goal and complements what is already being done with the support of a grant from the Endangered Landscape Programme and numerous local partners. 

Flora and fauna of the landscape, including the common sandpiper. Image credits in order of appearance - Agatha Rucin, Fernando Teixeira, Agatha Rucin & Blue Nomads

The Wonderful Wilderness of Paul de Toirões

What we found lurking in our abandoned quarry

Tiago de Zoeten, Conservation Biologist, Mossy Earth

Flora Hentz, Partnership Project Coordinator, Mossy Earth

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Rewilding Paul de Toirões -  Management Plan.pdf

This former mining site is now home to a vibrant array of wildlife. Discover why and how we're expanding and diversifying these rare wetland habitats in Portugal.

Rewilding a Former Mining Site

Handing an exploited landscape back to nature

Paul de Toirões is an important area for landscape connectivity in northwest Portugal where nature is recovering from years of mining. The 300-hectare property boasts one of the largest water surface areas in the Greater Côa Valley, consisting of lagoons, canals, and ponds. Its diverse range of environments are connected by seasonal flooding which supports a variety of wildlife and vegetation. In an area managed by our partners, Rewilding Portugal, this project presents an excellent opportunity to expand its habitats and establish a stronghold for wilderness in the region. Starting with our first intervention, we aim to enlarge and diversify the habitats through earthworks.

In spring 2024, our plant specialists, Udo and Claudia Schwarzer, conducted the aquatic plant survey at Paul de Toirões to:

Evaluate plant species and communities at the intervention site.

Access species abundance and distribution throughout the quarry.

Compare data collected last autumn with the data collected in spring.

Both the autumn 2023 and spring 2024 assessments confirmed the presence of several red-listed and rare species, including Utricularia australis, Potamogeton trichoides, Littorella uniflora, and Nitella mucronata - a macroalga not recorded in Portugal since 1942. Comparing with results from the Autumn survey, in spring we found a few more red-listed species to add to our list: Isoetes histrix, Isoetes setaceum and Elatine macropoda.

In addition to this, water samples were taken and analysed for various parameters, including pH, conductivity, ORP, temperature, carbonate hardness, phosphate, and chlorides. An ROV and divers also explored the Big Blue Lake to assess its depth and morphology.

The results were far from what we had expected. Our partners at Rewilding Portugal had even placed friendly bets on the lake's depth, some estimating it might be close to 30 meters deep. Imagine our surprise when we discovered the lake is mostly 1.40 meters deep, reaching 2.40 meters in some parts.

We also uncovered the secret behind the lake’s distinctive white-bluish coloration. The lake's bottom is composed of white clay that forms a floating mud, which, along with the shallow depth, gives the lake its opaque hue. This lake also exhibited higher pH and conductivity than the other water bodies, likely due to the presence of chlorides. Chlorides are usually absent or low in natural waters, suggesting either anthropogenic pollution or extraordinary mineralization, possibly from thermal water. Confirmation of this hypothesis would require a drone equipped with a thermal camera to detect temperature anomalies in the lake water.

Another significant discovery at the Big Blue Lake was the high density of invasive Louisiana crayfish. This could explain the near absence of rooted underwater plants, except for the floating carpets of Ranunculus peltatus (a species we had not yet found at the quarry), which can survive unrooted and withstand constant crayfish attacks.

These results were truly fascinating and continue to highlight the diversity of aquatic habitats that are present at the old quarry. The survey emphasised the ecological importance of Paúl de Toirões as a diverse and dynamic pondscape, home to rare species and essential natural processes. Despite some surprising findings, these insights are crucial and will serve as a foundation for our future conservation and rewilding initiatives.

Here is a selection of species found during the field visit in May 2024.

Update on the site surveys completed in spring 2024.

Aquatic plant survey

Spring aquatic plant survey

The surprises of the Big Blue Lake

The invasive Louisiana Crayfish

Aquatic plant survey