Whitepaper: From Biodiversity to value

The gap between how nature is measured and how decisions are made

Nature is measured in one language and managed in another. Ecologists count species, while the people who decide how coastlines are built, how are licensed, and how capital is allocated weigh costs, risks, dependencies, and returns. Both accounts are accurate, but they do not translate into one another, and the distance between them is where the value of a functioning ecosystem tends to disappear before a decision is ever made.

A development can be approved on the strength of an environmental assessment that counted the species at a site but recorded almost nothing about what those species actually did for the people nearby, so the value about to be lost never enters the decision. Understanding why that gap persists, and why it has become urgent, means looking at how biodiversity is recorded today, how decisions are actually taken, and what is lost in the space between them.

The most common changes range from population reductions to global extinction caused by overexploitation or habitat loss. Global or regional losses of species are only the last steps of marine biodiversity decreases. Not all species decline in abundance because of human activities, highly invasive species can colonize new regions and eventually form monocultures. Although the arrival of new species may seem like an increase in species richness, the consequences for the local biodiversity are generally negative.

HOW BIODIVERSITY IS MEASURED TODAY

Conventional biodiversity metrics are dominated by composition, recording species counts, taxonomic richness, and abundance at a point in time. These measures are reasonable proxies for ecological health, and because they are and comparable across sites and over time, they have become the default, even though gathering them at sea is neither cheap nor simple. What they describe is what is present in a system rather than what it does. The functional processes that generate value for people, among them nutrient cycling, sediment filtration, the maintenance of water quality, and the provision of physical habitat, are largely absent from the standard ecological survey (Cardinale et al., 2012; Mace et al., 2012). A species list can stay reassuringly stable while the processes that depend on those species weaken beneath it.

The Millennium Ecosystem Assessment set out the conceptual link between ecosystem condition and human well-being two decades ago, introducing the distinction between provisioning, regulating, cultural, and supporting services that still the field (MEA, 2005).

Science is not the obstacle. Methods to measure what an ecosystem does have existed for decades; what has been missing is their routine use in the decisions that depend on them. The gap is one of practice, not knowledge.

HOW DECISIONS ARE MADE

The people who decide the fate of ecosystems rarely work from species lists. They work in the language of risk, dependency, and financial value.

A planning authority weighing a coastal scheme asks what natural flood protection it would remove. A lender or investor asks whether a business depends on natural resources that are running short, because if they are, the business is exposed. And a company must now to its regulators and to the market, how it depends on nature and how it affects it.

The EU Taxonomy, the Taskforce on Nature-related Financial Disclosures, and the Global Reporting Initiative's biodiversity standard all now call for nature to be reported in these terms (TNFD, 2023; GRI, 2024), and a species count cannot supply it. So the decisions still get made and the reports still get filed, but the data to hand cannot tell anyone what is actually at stake.

THE COST OF THE GAP BETWEEN MEASUREMENT AND DECISION

That mismatch is the mechanism through which biodiversity loss is systematically underpriced. When the unit of measurement is the species and the unit of decision is value, the connection between ecological condition and material consequence stays out of view.

The decline that follows a loss, in water filtration, coastal protection, carbon storage, and fisheries, is left unquantified, and so absent from the calculations that govern investment and land and sea use. Economic modelling has linked continued biodiversity and ecosystem-service loss to damages in the order of trillions of dollars a year by mid-century (TEEB, 2010; WEF, 2020).

There is a further consequence in how loss is dealt with once it is . Where harm to nature is unavoidable, the established response is to compensate for it, often through offsetting that restores or protects habitat elsewhere, measured as no net loss against a baseline. That approach has its place, but it is loss-accounting by design, and it carries the same blind spot. A species count cannot show whether the gain claimed in one place genuinely replaces the function lost in another. As policy moves from compensating for loss towards requiring measurable gain, the ability to quantify what an ecosystem does, rather than only what lives in it, becomes the difference between a gain that can be demonstrated and one that can only be asserted.

Service decline follows the biodiversity loss: the European evidence

The claim is simple, and the evidence backs it. Lose biodiversity and you lose the services it provides. The relationship runs in both directions, and where biodiversity is rebuilt, services return, often more fully than the starting conditions would suggest. Both can be measured.

This link has been documented across more than 500 peer-reviewed studies in terrestrial and marine systems under land and sea-use intensification (Ricketts et al., 2016). It is not always a straight line. Depending on the service and the system, loss can be gradual, exponential, or around thresholds that produce rapid collapse once crossed; some services fall in step with biodiversity, while others are held up by functional redundancy until a critical point gives way (Ross et al., 2021). Knowing which pattern applies is precisely what integrated assessment, rather than the species inventory, establish. Without it, managers and investors cannot see where the thresholds lie, and so cannot act before they are passed.

THE COLLAPSE OF EUROPE'S NATIVE OYSTER REEFS

The European native oyster, Ostrea edulis, is a well-documented case of service loss driven by the collapse of a foundational species. Its reefs once covered an estimated 1.75 million hectares across European seas, forming three-dimensional structures that filtered large volumes of water, sheltered fish and invertebrate communities, and gave the seabed much of its physical character (Thurstan et al., 2024). From the nineteenth century onwards, industrial fishing and dredging, compounded by declining water quality, introduced pests, and disease, reducing them until the habitat was functionally lost across European waters (zu Ermgassen et al., 2026).

What the record cannot tell us is what that loss was worth. Because those services were never measured in the terms this paper describes, the value Europe forfeited can only be estimated in hindsight, never stated with confidence, and that absence is the lesson. The collapse was recorded, as a species and a habitat gone, not as the filtration, the fisheries, and the coastal protection that went with them, a loss a composition-only assessment was never equipped to count.

SERVICES RETURN WHEN BIODIVERSITY IS REBUILT

The relationship is just as clear in reverse, and here the evidence is more encouraging. In European waters, native oyster reef restoration is now being pursued at the ecosystem scale, with early projects recovering reef structure together with the filtration, habitat, and biodiversity functions that come with it (zu Ermgassen et al., 2026). Meta-analysis of oyster reef restoration across many sites confirms that restored reefs deliver measurably greater filtration, fish production, and shoreline protection than degraded habitat (Smith et al., 2022).

In Wales, the Seagrass Ocean Rescue has re-established Zostera marina from seed at Dale Bay in Pembrokeshire, providing a peer-reviewed and scalable model for seagrass recovery in north-west European waters that is already being applied at further sites (Unsworth et al., 2019). In the coastal bays of Virginia, the reseeding of roughly 9,000 acres of eelgrass produced rapid and measurable recovery across several services at once, in fish and invertebrate abundance, water clarity, and the burial of carbon and nitrogen (Orth et al., 2020).

The scale of what is at stake is clearest in the blue-carbon record. Seagrasses cover less than 0.2% of the ocean floor yet account for around 10% of annual ocean carbon burial, and coastal blue-carbon systems are estimated to contribute on the order of US$190 billion a year in carbon value globally (Macreadie et al., 2021). In the Mediterranean, a natural-capital assessment of Posidonia oceanica meadows placed their per-area value among the highest of any ecosystem, driven by the combination of long-term carbon burial, water purification, and coastal protection (Vassallo et al., 2013). These are measured outputs of functioning communities, values that disappear when the community is lost and return, as the restoration record now shows, when it is rebuilt.

Taken together, the degradation and recovery cases establish the same bidirectional and quantifiable link: biodiversity loss drives service decline, and biodiversity recovery drives service return, in ways consistent enough and measurable enough to support decisions.

Where building is unavoidable, it can give back

Measuring the problem does not fix it; building differently does. The argument has a final step, which is intervention, and a particular condition attached to it. Where coastal and marine infrastructure has to be built, it can be designed to rebuild ecological function rather than remove it. The infrastructure that has replaced natural habitat, the seawalls, breakwaters, port structures, and platforms, has historically done so by substituting inert, simple surfaces for complex, living ones, with a net loss of function that compounds with each addition.

Much of that building is unavoidable. Ports will be expanded, shorelines defended, and energy built offshore, and each carries an ecological cost that no design removes entirely. The realistic question is not whether to build but how, and where a structure is going up, regardless, the case for making it give something back rather than nothing is straightforward, the more so now that the means to do so are readily available rather than experimental. Ecological engineering reverses the logic, treating built surfaces as opportunities for habitat rather than obstacles to it.

The relationship documented on natural reefs and seagrass beds does not stop at the edge of a built structure. The same colonising communities and the same filtration, habitat, and stabilising functions establish on a hard surface when it is designed to receive them, which is why a seawall or breakwater can recover function by the very mechanism the previous section described. The evidence for this is peer-reviewed and growing. Eco-engineered marine concrete designed with appropriate texture, porosity, and chemistry supports markedly higher invertebrate and fish abundance, richness, and diversity than standard designs, alongside a lower ratio of invasive to native species. EU-funded demonstration work, such as the Living Ports project, has shown the same effects at the scale of a working port (EU Living Ports project, CORDIS, 2023). These are recoveries of function, not cosmetic gains, and they can be quantified with the same approach used to document the original loss.

The significance is that a single intervention can produce both kinds of value at once, the ecological recovery this paper has described and the economic value that becomes legible once that recovery can be measured. These are not separate achievements but one achievement seen from two sides, and they are realised only when a solution is designed from the outset to be monitored. An assessment is only as good as the data available to it, and the richest data comes from solutions built to generate it.

It is here that measurable ecology becomes a financeable value. Once a benefit can be quantified and verified, it can be weighed, reported, and invested in like any other return, and the advantage lies with infrastructure that is not merely installed but engineered to produce the evidence of what it does.