The intensification of existing farmland can sometimes be more harmful to local biodiversity than expanding the area covered by agricultural land, according to new research just published in Nature Ecology and Evolution.
The study shows that neither expansion nor intensification is consistently better for biodiversity, as it varies by factors including region, crop type and local vegetation, challenging the conventional wisdom in favor of intensification that encourages farmers to improve the productivity of existing farmland with techniques such as increased fertilizer and pesticide use.
"Feeding the global human population comes at an increasing cost for our planet's biodiversity. To mitigate this, the common assumption is that intensifying agricultural practices is always less detrimental to biodiversity than farmland expansion," explains lead author Silvia Ceaușu from the University College London (UCL) Centre for Biodiversity & Environment Research. "Our research highlights that it's actually more complicated than that. We show that farmland expansion is indeed drastically changing local biodiversity".
The authors further note that once agriculture is established, intensifying agricultural practices can further degrade local biodiversity, sometimes more so than by further removing natural vegetation from the area and that closing 'yield gaps' - maximizing production on existing agricultural land in a given area - could come at a higher ecological cost than previously thought.
The team conducted a global assessment of the impacts on biodiversity from farmland intensification or expansion using a large biodiversity database, natural vegetation data, and agricultural yield estimates. They looked at existing agricultural areas (with varying amounts of natural vegetation near the farms; natural areas without any agriculture were excluded) producing maize, soybean, wheat, and rice - four common crops that together represent over half of the total global calorie production.
To measure biodiversity, the study looked at species richness (how many different species are in an area), total abundance (how many individuals there are of each species), and the geographical distribution of each species, taking into account both the agricultural area and the surrounding areas.
The researchers found that overall, increasing crop production by either route is harmful to biodiversity, but also that which approach (expansion or intensification) is more harmful depends on the context, including factors such as the region, crop type, or characteristics of the remaining natural vegetation, as well as which measure of biodiversity was used.
The authors say their findings could have relevance for global agricultural policies and trade initiatives, particularly those aimed at curbing deforestation, as some have requirements for crops to come only from established farmland, which may be an oversimplification of the evidence.
While it is very complex to determine in which situations expansion or intensification is less harmful, the authors suggest that farmers could focus on sustainable intensification techniques, such as biological pest controls and keeping patches of natural vegetation between fields. For consumers, given the complexities involved in determining the sustainability of different products, reducing food waste and meat consumption may be a more effective option
"Finding the most sustainable way to increase crop yields is very complicated and depends on numerous factors, so simple suggestions like favoring farmland intensification over expansion are not always effective - there's no one-size-fits all solution for sustainable agriculture," says study coauthor Tim Newbold from the UCL Centre for Biodiversity & Environment Research.
The researchers caution that their study only looked at existing agricultural areas and does not suggest that cultivating natural areas would be appropriate.
"We would not suggest expanding farmland into intact natural areas as it is vital for the planet that such unmodified landscapes are preserved," added Newbold.
"In order to protect biodiversity while meeting food demand, we may need to rethink how we balance expansion and intensification in agriculture. There is likely a balance that can be struck between intensification and expansion in agricultural landscapes, informed by local and crop-specific data and considering the full range of environmental impacts," concludes study coauthor David Leclère, a senior research scholar in the Integrated Biosphere Futures Research Group of the IIASA Biodiversity and Natural Resources Program.
The study was supported by the UK Global Challenges Research Fund Trade, Development and Environment Hub.
Adapted from a press release prepared by University College London (UCL). Read the original article.
Reference
Ceaușu, S., Leclère, D., Newbold, T. (2025). Geography and availability of natural habitat determine whether cropland intensification or expansion is more detrimental to biodiversity. Nature Ecology and Evolution DOI: 10.1038/s41559-025-02691-x
