Researchers say biodiversity compensation works best with long-term recovery, the right landscape setting, and enough land for restoration.
A new study identifying the ecological conditions needed for biodiversity offsetting to achieve conservation goals could provide important guidance for governments and industries as they expand biodiversity net gain (BNG) and nature restoration policies.
Biodiversity offsetting is increasingly used to compensate for environmental damage caused by development. It sees habitat loss in one location compensated through habitat restoration or protection elsewhere, with the aim of achieving no net loss of biodiversity.
The latest research, led by Swansea University in collaboration with the UK Centre for Ecology & Hydrology (UKCEH) and Forest Research, shows that biodiversity offsets are far more likely to succeed when restoration areas are larger than impacted habitats, are protected over long timescales, and designed around how ecosystems recover over time.
The findings address one of the central challenges in modern conservation policy - how to compensate for biodiversity losses caused by development while societies continue to demand land for housing, infrastructure, food production, and economic growth.
However, the study shows that biodiversity outcomes depend on repeated cycles of habitat loss, restoration, and ecological recovery unfolding over decades. When mature ecosystems are replaced with newly restored habitats, biodiversity can decline for extended periods before ecological functions recover. In some cases, recovery may never fully occur if habitat conversion continues too rapidly.
Using large-scale ecological simulations, the researchers examined how forests and habitat-dependent species responded to repeated cycles of development and restoration over centuries. The model incorporated forest succession, landscape change, species recolonisation, and constraints on land availability.
The results show offsetting outcomes depends on:
- the scale of compensation;
- the duration of conservation protection;
- the rate of habitat conversion; and,
- whether sufficient land remained available for restoration.
The study also found that high rates of ongoing habitat loss sharply reduced the likelihood that offsets could maintain biodiversity, particularly for species dependent on mature ecosystems.
Lead author Dr Konstans Wells, from Swansea University's Biosciences department , said: "Biodiversity offsets are often evaluated using short-term habitat gains, but ecosystems recover over much longer timescales. If mature habitats are removed and replaced with newly restored sites, there is an unavoidable ecological deficit while those ecosystems recover."
The researchers explain that this creates a fundamental challenge for biodiversity policy. In practice, development typically removes habitats with relatively high ecological integrity, while compensation usually occurs on more degraded land because these are the areas available for restoration. As a result, biodiversity compensation is rarely a simple exchange of equal ecological value.
Co-authors Professor Luca Börger and Dr Miguel Lurgi compared the challenge to "trading a full bottle of your favourite beverage for several empty bottles - if those bottles never refill, the exchange ultimately fails".
The study shows that whether those bottles refill depends on ecological recovery rates, landscape context, and whether species populations can persist long enough for restored habitats to become suitable again.
The researchers emphasise their findings are not an argument against biodiversity offsetting but instead identify the conditions under which offsetting is more likely to succeed.
According to the researchers, the findings highlight the importance of integrating biodiversity offsets within broader strategies that prioritise avoiding habitat loss.
The authors conclude that successful biodiversity compensation requires policies aligned with ecological reality - ecosystems recover gradually, species depend on long-term habitat continuity, and restoration outcomes are shaped by processes unfolding over decades.
