Surprise. When humans disappear, nature can become impoverished

For decades, one of the most widespread beliefs in environmentalism has been that nature is all the better for the less humans interfere with it. The resulting image is a familiar one: an abandoned village, fields overgrown with trees, wild animals returning. An article by Emma Marris published on 4 November in Nature, exploring the effects of the disappearance of inhabitants from rural areas, invites readers to consider an uncomfortable possibility: in certain places, the absence of humans impoverishes biodiversity.

To understand why, one need only look at a mountain meadow. Many European meadows that we now regard as natural landscapes exist in their current form because, for centuries, people have brought animals there to graze or have cut the grass. Grazing limits the growth of shrubs; mowing prevents a few more competitive plants from dominating the others. The result is an open environment in which numerous species of flowers, insects and birds can coexist, often with very specific ecological requirements. When these activities cease, ecological succession begins: shrubs spread, trees take over the ground and the shade gradually eliminates many meadow species. The forest that forms can support other life, whilst species dependent on open spaces lose their habitat.

This phenomenon can be measured. In seven protected areas in the Czech Republic, a group of researchers compared historical and recent aerial photographs with data on the presence of butterflies and moths. With the expansion of forest cover and the disappearance of open habitats, the reserves have, on average, recorded a loss of 26 per cent of previously documented butterfly species and 19 per cent of moth species. This finding relates to areas that are already protected: designation as a reserve has not prevented an ecological transformation that is harmful to part of the fauna.

The issue directly affects Italy. In the Alpine valleys and inland areas of the Apennines, the abandonment of agro-pastoral practices is encouraging the encroachment of woodland and the closure of meadows. A 2026 study on the dry meadows of the Val di Susa reconstructed precisely this process, demonstrating the extent to which current biodiversity depends on the former extent of the pastures and the history of their use. The European Environment Agency also recognises the abandonment of species-rich meadows as one of the threats to specialised butterflies. Its meadow butterfly indicator fell by 47 per cent across the European Union between 1991 and 2024, due to the combined effect of agricultural intensification, habitat loss, abandonment and other factors. This figure stems from a number of causes, but it highlights the fragility of these ecosystems. A 2026 European Commission document estimates that one third of habitats of Community interest require active agricultural management, particularly extensive grazing.

The same logic applies in a very different landscape: that of Japan’s satoyama. These are mosaics of rice paddies, small traditionally managed woodlands, ponds and meadows, maintained for generations through the labour of rural communities. Their variety of habitats supports species that depend on periodic human activities, such as the irrigation of rice paddies or the cutting of vegetation. The ageing of the farming population and the abandonment of land are undermining these balances, to the extent that the OECD has highlighted their decline in its 2025 environmental review of Japan.

The effects of abandonment depend on the history of the area. Where agriculture has replaced native forests, spontaneous regeneration can restore valuable habitats. A study published in 2024 in Nature Sustainability, which examined 1,322 species of birds and mammals across eleven areas on four continents, estimated that the abandonment of cultivated land has increased the available habitat for 62.7 per cent of the birds and 77.7 per cent of the mammals considered. This represents significant evidence that allowing space for regeneration can be effective. Europe’s semi-natural grasslands and Japan’s traditional rice paddies offer further perspective: where entire biological communities have developed alongside sustainable human practices, discontinuing these practices means altering the conditions on which those communities depend.

The political issue, then, is far from marginal. If an area preserves its biological wealth through mowing, extensive grazing or the maintenance of small water systems, those who carry out these activities also fulfil a conservation role. A policy that merely funds the purchase of land to be taken out of human use may fail precisely where it aims to protect nature. In certain landscapes, it is necessary to provide financial support to those who continue to live in and manage them, recognising the ecological value of practices that the market, on its own, does not reward. This requires distinguishing between intensive agriculture – which is often responsible for severe losses of biodiversity – and extensive management, which preserves valuable habitats.

The fundamental error lies in imagining a single possible relationship between humans and nature, always expressed in terms of the degree of disturbance. Biology requires us to ask which species inhabit a given place, which processes enable their survival, and what happens when those processes change. In many regions of the world, human beings too have, over the course of centuries or millennia, become part of the ecological history of the landscape. Their disappearance may be a liberation for some species and a catastrophe for others. Conserving biodiversity requires an understanding of this history, even when it forces us to recognise that human presence may be a condition for its survival.