Shifting baseline syndrome (SBS) erodes our connection to the natural world. With each generation, we come to accept a little less biodiversity, fewer wild spaces, and a more degraded environment as “normal.” This creeping tolerance for decline makes it harder to recognise what we’ve lost, and even harder to imagine what true recovery could look like. In this blog, we’ll unpack how SBS shapes our perceptions of nature, why it matters for conservation, and what’s at stake for the future.
In simple terms, we perceive what a ‘healthy’ natural environment looks like relative to what we have experienced in our lives. Over time, this means we accept a gradually diminished natural world, as each new generation fails to fully appreciate what has already been lost.
A key proponent of the concept was fisheries scientist Dr Daniel Pauly, who described how scientists perceived the condition of fish communities (in terms of species and body sizes) based on what they experienced early in their careers (Pauly, 1995). Each generation of fisheries scientists accepts a gradually declining community as the new norm. Over time, this results in a shifting baseline that accommodates degraded fish communities with smaller individuals and fewer species. As Pauly put it in a TED talk in 2010, “we transform the world, but we don’t remember it”.
We become acclimatised to the degradation of the natural world and accustomed to the loss of rare species.
Take fish as an example. In the UK, rivers have lost several species in recent history: the Burbot (a freshwater cod), which was last confirmed on the Old West River, Cambridgeshire in 1969 (Worthington et al, 2010) and the last native sturgeon (we once had two species – Atlantic and European) was last seen on the River Tywi, South Wales in 1993 (UK Sturgeon Alliance, 2025). Populations of these fish had already declined markedly for centuries, meaning each generation would have grown used to them becoming rarer.
I was only two years old when a sturgeon was last sighted in a UK river, so I have no memory of them being even rare, let alone common. How many generations back must we go to understand what their populations could (and should) be like? How do we calibrate our perspective between a present with no burbot, and the 1500s when they were apparently so abundant that they were fed to pigs and used as fertiliser!?
The plight of the Atlantic salmon offers a real-time example. UK stock assessments show clear declines in recent decades (Environment Agency and Natural England, 2024; Scottish Government, 2025), and in 2023 our main population was reclassified as endangered on the IUCN Red List (Darwall and Noble, 2023). In 1922 the UK rod caught record for Atlantic salmon was set Georgina Ballantine with a 64lb leviathan from the River Tay, Scotland. That record has now stood for over a century. The pattern repeats: individuals grow smaller, populations grow sparser, and then ‘suddenly’ they are gone. Each generation acclimatises to a once-abundant species becoming rare, in this case shifting from a keystone to a flagship species.
My great uncle, Cyril Bennett, is a man mad for mayflies. So much so that he was given an MBE for services to riverfly conservation (though one might suspect it was a royal classification of ‘Mayfly Bothering Eccentric’). If he and I were to stand by a river and watch a mayfly hatch, our expectations would be defined by our experiences. I have not seen mayfly hatches in the southern chalk streams of the same magnitude that my uncle saw years ago. What for me might be an exciting interaction with nature could leave Cyril disappointed about the river’s decline.
This acceptance of the status quo because it is all we know, becomes the shifting baseline of our ecological expectations. The risk is that increasing generational tolerance for environmental degradation lowers the bar for potential recovery in the future.
A review of SBS proposed three main causes (Soga and Gaston, 2018).
1. Lack of environment data
The first and key driver is a lack of data about the natural world. Most ecological timeseries datasets were only established relatively recently. Many European biodiversity recording schemes began in the late 20th century, long after human impacts had already degraded ecosystems (Mihoub et al., 2017). This means inappropriate baselines could be set that limit our expectations of what is or should be possible.
For example, RIVPACS is a statistical model used to assess river health (under the Water Framework Directive) by comparing invertebrate communities to those expected at ‘pristine’ sites. However, this reference data was primarily collected between 1978 and 2002. So, as its developers note: “realistically no river is unaffected by human activities, the reference sites represent the best examples of their type with the least impact” (UK CEH, 2025). Methods like RIVPACs are undoubtably doing the best they can with the available data and are helpful tools. But we must remember their limitations and perhaps treat positive classifications as the minimum acceptable outcomes, not gold standards.
2. Extinction of experience
The other two drivers of SBS fall under “extinction of experience”: a loss of direct interaction with, and familiarity of, the natural world. This is easy to see today. We spend more time indoors, in urban areas, and in managed interactions with nature. This is particularly true for counties like the UK which is among the most nature depleted on earth. As we lose contact with nature, our ability to judge ecological change weakens.
Future societal trends may amplify this problem. In the UK, urban populations are projected to grow while rural populations decline (Government Office for Science, 2021). It has been claimed that “water quality is better now than at any time since the Industrial Revolution”. But research shows that while urban water quality has improved, rural water quality has likely declined (Whelan et al., 2022). If more of us live in cities, will our baselines be shaped by perceptions of urban improvement (from a low starting point), while we lose touch with declines further afield?
Given centuries of development, it is naïve to think we can fully turn back the clock. Rivers, floodplains, and catchments have been drastically altered, and climate change is now reshaping hydrology and temperature regimes in real time. But the point is this: we would not recognise a pre-industrial baseline even if we saw it. In 2025, we simply lack both the data and the lived experience. As the impact of human activity on the natural world becomes more severe, recognising the challenges of conservation is increasingly essential. Critically, we must not let our limited perception of nature constrain its potential for recovery.
What can we do to counter a phenomenon that exists because at some point we (be it the individual or generation) won’t? Soga and Gaston (2018) propose several recommendations.
1. Restore nature
Environmental restoration is critical for combatting the gradual degradation of the natural world that is the root of SBS. For rivers, this means reconnecting them to floodplains, recreating natural habitats, and above all improving water quality. In principle shifting baselines do no need to be following a negative trend over generations. Perhaps we can turn the tables and begin ‘lifting baselines’ following our successes (Roman, 2015).
2. Monitor and collect data
We need to continue to collect high quality environmental data so that we mitigate SBS within and beyond our lifetimes. Modern advances now give us unprecedented insights into ecological and environmental change. The challenge is ensuring this data informs policy, rather than just documenting decline. Evidence must drive decision-making.
3. Reduce the extinction of experience
We need to expand opportunities for people to interact with nature and encourage people as to the benefits of interacting with nature in our modern world. A society connected to its environment is better equipped to perceive, and act on, change.
4. Educate
As always education is key. We need to teach people about the natural world they currently live in so that they are better able to reconnect. Also, to show people what aspects of nature have been lost and why that matters.
Momentum for improving the health of our rivers is building. Water quality and freshwater health are now regular topics in public debate, and the value of blue spaces – for both biodiversity and human wellbeing – is increasingly recognised. Creating opportunities for people to connect with rivers and nature must remain a priority.
Volunteering for restoration projects is a powerful way to take action. At WildFish, our SmartRivers citizen science programme enables local communities to collect scientifically robust data that strengthens understanding and drives river restoration.
But even something as simple as spending time by a river helps deepen our awareness of ecological change, and it’s good for mental wellbeing too.
Barriers remain. Projects are too often shaped by ‘realistic targets’ that undercut ambition, while personal memories of nature’s richness are dismissed as ‘rose-tinted’. This conservatism risks locking in a diminished vision of recovery, constrained by economics and short-term priorities.
Despite the challenges of defining them, baselines are essential for halting the loss of the irreplaceable.
So, what should our baseline for nature be today? Surely not the depleted landscapes we see around us. And what’s the real risk of aiming high, that we end up with healthier rivers, thriving wildlife, and more resilient ecosystems? The greater danger is setting the bar too low, and in doing so, limiting the future of the natural world.
List of references
Darwall, W., Noble, R. 2023. Salmo salar (Great Britain subpopulation). The IUCN Red List of Threatened Species 2023: e.T213546282A213546288.
Environment Agency and Natural England (2024). Press Release: Salmon stocks in England lowest on record. https://www.gov.uk/government/news/salmon-stocks-in-england-lowest-on-record. Accessed: 28/08/25.
Government Office for Science (2021). Trend Deck 2021: Urbanisation. https://www.gov.uk/government/publications/trend-deck-2021-urbanisation/trend-deck-2021-urbanisation. Accessed: 28/08/25.
Mihoub J-B., et al. 2017. Setting temporal baselines for biodiversity: the limits of available monitoring data for capturing the full impact of anthropogenic pressures. Scientific Reports 7: 41591.
Pauly D. 1995. Anecdotes and the shifting baseline syndrome of fisheries. Trends in Ecology and Evolution 10(10): 430.
Pauly D. 2010. The oceans shifting baseline. TED. https://www.ted.com/talks/daniel_pauly_the_ocean_s_shifting_baseline. Accessed: 28/08/25.
Scottish Government (2025). The status of salmon in Scotland: 2025. https://www.gov.scot/publications/status-of-salmon-in-scotland/pages/decline-in-adult-salmon-numbers/. Accessed: 28/08/25.
Soga M., Gaston K. 2018. Shifting baseline syndrome: causes, consequences, and implications. Frontiers in Ecology and the Environment 16(4): 222–230.
UK Centre for Ecology and Hydrology. RIVPACS reference database. https://www.ceh.ac.uk/data/software-models/rivpacs-reference-database. Accessed: 28/08/25.
UK Sturgeon Alliance. Help us save the UK’s native sturgeon. https://www.savethesturgeon.com/. Accessed: 28/08/25.
Whelan M., et al. 2022. Is water quality in British rivers “better than at any time since the end of the Industrial Revolution”? Science of The Total Environment 843: 157014.
Worthington T., et al. 2010. Former distribution and decline of the burbot (Lota lota) in the UK. Marine and Freshwater Ecosystems 20: 371-377.
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