In the grasslands around Milovice, Czech Republic, wisents graze alongside Exmoor ponies and Tauros cattle—a sight that would have been ordinary in Europe ten thousand years ago, but feels almost radical today. This rewilding is quietly restoring something scientists thought was lost: the insect diversity that once thrived when megafauna roamed free across the continent.
A new study from the Biology Centre of the Czech Academy of Sciences has quantified what conservationists hoped might be true. Over nearly a decade, researchers surveyed five groups of insects across eleven rewilded sites in the Czech Republic, comparing land grazed by large ungulates with adjacent ungrazed areas. The results, published in the Journal of Applied Ecology, show that returning these animals to the landscape works—at least for some of the insects that make ecosystems function.
The research team, led by entomologist Martin Konvička, found that species richness and abundance of bees and wasps increased significantly on grazed lands. Grasshoppers and crickets also flourished. Butterflies, moths, and ants showed no decline, even as their overall species numbers stayed flat. Importantly, no insect group was suppressed by the presence of large herbivores. "We were curious whether the return of large herbivores could at least partly replace those ecological processes which were lost from the landscapes by megafauna demise," Konvička explained. The answer, the data suggest, is yes—in measurable, meaningful ways.
What makes this discovery especially significant is not just which insects increased, but how they changed. The large ungulates—whether Exmoor ponies, Tauros cattle, or wisents—transformed the landscape into a patchwork. Some areas experienced heavy grazing; others remained sparsely touched; still others became bare ground. This mosaic of conditions favored smaller, less mobile insect species with precise habitat needs—the kind that can thrive on short herbs in a landscape shaped by hoofprints and browsing. "Large ungulates generate a diverse mosaic of conditions, from sparsely grazed spots to patches of barren land," Konvička said. "And it is this diversity of conditions which is crucial for many insects."
This matters because insects are disappearing across Europe at alarming rates, and most insect species evolved in an era when large herbivores were abundant sculptors of the land. After megafauna were extirpated—driven out by human hunting and habitat loss—traditional farming with cattle and horses partly replaced their ecological role. But industrial agriculture and plantation forestry have demolished what remained of those natural disturbance patterns. Rewilding with large ungulates essentially restores the evolutionary template on which entire insect communities were built.
The researchers caution this is not a universal fix. Some insects that depend on tall grasslands or undisturbed habitats may lose ground. Yet the solution, Konvička notes, is not to choose between grazed and ungrazed—it's to have both, allowing the ungulates' natural behavior, combined with predation and other ecological processes, to create the variety that diverse insect communities need.
For conservation managers, the implications are clear: large herbivores are not merely symbols of wilderness. They are ecological engineers, working for free to restore the landscape functions that expensive habitat management programs struggle to replicate. In rewilded areas large enough to let nature work, these animals may offer one of the most elegant answers to an unfolding crisis.