Under the pale skies of southern Spain, one of Europe’s best-known wetlands is quietly losing some of its oldest inhabitants.
Deep inside Doñana National Park, freshwater turtles that once crowded sunlit lagoons are vanishing from view, squeezed by shrinking waters and mounting human pressure.
Doñana’s turtles in freefall
A new scientific assessment from Spain’s Doñana Biological Station paints a stark picture. Two native freshwater turtle species, commonly known in Spanish as “tortugas Galápagos”, have crashed in numbers over just three decades.
The European pond turtle in Doñana has lost around three quarters of its known population in 30 years.
Researchers compared detailed surveys carried out in the early 1990s with fieldwork conducted between 2021 and 2024. The contrast is severe.
- European pond turtle (Emys orbicularis): population down about 74%
- Spanish terrapin or Iberian pond turtle (Mauremys leprosa): population down about 57%
- Range of the European pond turtle within the park: reduced by nearly 79%
The European pond turtle, already rarer and more demanding in habitat needs, has seen its distribution shrink dramatically. Today it clings to a handful of lagoons that still hold water long enough each year to sustain its full life cycle.
Areas where both species were once a routine sight — shallow, seasonal ponds scattered across the dunes and marsh edges — have dried out or now flood only briefly. For long‑lived reptiles that need stable, predictable wetlands, those changes are devastating.
What is driving the collapse?
Scientists point to one factor above all: water.
Overuse of groundwater is undermining the very hydrological engine that keeps Doñana’s lagoons alive.
The aquifer beneath Doñana sustains hundreds of small wetlands. For years, it has also been tapped aggressively for irrigation, especially intensive berry farms and other crops, and for tourism complexes around the coastal resort of Matalascañas.
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Rainfall in recent seasons has briefly filled some lagoons, creating eye-catching images of water returning to the park. Hydrologists insist those snapshots are misleading. Short wet spells do not repair the long-term deficit in the underground reserves that feed the wetlands through the year.
More than 80% of Doñana’s lagoons now show a shorter “hydroperiod” — the time they stay inundated annually. In practical terms, they dry out earlier in spring or fail to hold water through critical months for breeding and growth.
Why hydroperiod matters for turtles
Freshwater turtles in Mediterranean climates have evolved to cope with some seasonal drying. Yet their eggs and hatchlings still need reliable pools for many weeks. A compressed hydroperiod breaks that rhythm.
Shorter flooding periods can:
- Expose eggs or hatchlings to heat and predators as ponds vanish too early.
- Reduce the availability of aquatic invertebrates and small fish they feed on.
- Force adults to move more often over land, increasing roadkill and predation.
- Fragment populations, isolating small groups in scattered permanent ponds.
In Doñana, many temporary ponds that once acted as stepping stones between larger wetlands now remain dry for much of the year. That cuts genetic exchange between turtle subpopulations and raises the risk that local extinctions become permanent.
An early warning for the entire wetland
The two turtle species are not just victims of change. They are also powerful messengers of what is happening beneath the surface.
When pond turtles vanish, it signals a broader unravelling of the wetland community.
As mid‑level predators and scavengers, these turtles help regulate aquatic food webs. They consume insects, tadpoles, carrion and plant matter, keeping algal growth in check and recycling nutrients. Their shells carry algae and small organisms from pond to pond, subtly linking habitats.
A sharp decline in turtles usually means something is going wrong for many other residents of the same waters: amphibians that need clean ponds for spawning, dragonflies that depend on healthy aquatic larvae, and wading birds that feed in shallow pools.
Doñana is a flagship reserve for Europe, a crucial stopover for millions of migratory birds. If its small lagoons continue to degrade, the ripple effects will not stop at reptiles.
From protected area to pressured landscape
The case worries conservationists precisely because Doñana is already one of Spain’s most heavily protected spaces, recognised under national and EU law and listed as a UNESCO World Heritage Site.
The turtle data show that high legal status does not automatically shield wetlands from slow, cumulative damage. Official protection can be undermined when groundwater pumping, illegal wells and expanding agriculture are tolerated or poorly controlled in the wider region around the park.
Researchers warn that, without stricter water management and serious restoration of permanent lagoons, the two turtle species could reach a status comparable to “critically endangered” at local scale, even if they remain more secure elsewhere on the Iberian Peninsula.
What recovery would actually look like
Scientists involved in the study are blunt: hoping for a run of wet winters will not be enough. They argue for a long‑term restructuring of how water is used in the area.
| Proposed action | Expected benefit for turtles |
|---|---|
| Cutting illegal groundwater extraction | Stabilises aquifer levels and lengthens lagoon hydroperiods |
| Reducing irrigated surface near sensitive zones | Lowers demand peaks in dry months and leaves more water for wetlands |
| Restoring natural lagoon basins and edges | Improves breeding sites and refuge areas for adults and hatchlings |
| Monitoring turtle populations regularly | Provides early signals of further decline or recovery |
Such measures are politically contentious. They touch on jobs in farming and tourism and on regional development plans. Yet hydrologists caution that postponing decisions tends to lock in deeper ecological losses and makes later recovery more expensive and uncertain.
Why freshwater turtles matter more than people think
Freshwater turtles rarely generate the kind of global attention that big mammals or iconic birds receive, but they are among the most threatened vertebrates on the planet. Globally, well over half of turtle and tortoise species face some level of extinction risk due to habitat loss, water pollution, climate shifts and the pet trade.
The situation in Doñana fits into that global pattern, with one twist: here the problem is less poaching or exotic trade, and more the silent draining of their environment.
For visitors, turtles are often one of the few larger animals easy to see during the day, basking on logs or floating near the surface. Their absence makes wetlands feel strangely empty, even when birds are still present overhead.
Key terms people keep asking about
The debate around Doñana often uses technical language. Two expressions in particular shape the fate of its turtles:
- Aquifer: A body of rock or sediment that stores groundwater. Think of it as a slow‑moving underground reservoir. Pumping too much, too fast, drops its level and cuts the natural springs and seepages that feed surface ponds.
- Hydroperiod: The length of time a wetland holds water during a year. Longer hydroperiods tend to favour species needing stable conditions, like turtles and many amphibians. Shorter hydroperiods favour only the hardiest species and can shift a lagoon towards being more like a dry depression than a functioning pond.
Changes in these two elements do not just affect reptiles. They alter how carbon is stored, how nutrients flow and how resilient the landscape is to drought.
What could happen next
If the current trajectory continues, Doñana could face a patchy future where only a small network of deep or artificial ponds still hold turtles, while vast areas that once supported them become seasonally barren. That scenario would mean smaller, more isolated turtle groups, more inbreeding and a higher chance that one bad year wipes out whole colonies.
On the other hand, tighter control of groundwater, combined with active lagoon restoration, could slow the decline within a decade. Young turtles take years to reach breeding age, so any rebound will be slow. Policymakers working on five‑year plans are effectively deciding what the wetland will look like for the next half‑century of turtle generations.
For many scientists, the question is no longer whether Doñana’s turtles are in trouble, but whether regional authorities, farmers and tourism operators are ready to treat water as a finite common asset rather than an endless resource. The answer will decide if those ancient reptiles still bask on the park’s shores by mid‑century, or survive only in historical photographs and field notes.