Wild animals reshape soil and sediment across landscapes

A new analysis has revealed that wild animals affect the movement of soil and sediment much more strongly than scientists had previously measured.

The findings change how landscapes are understood, placing everyday animal activity at the centre of the processes that shape rivers, soils and landforms.

Evidence of animal impacts across ecosystems

A pattern emerged across 64 studies covering rivers, lakes, burrows and feeding grounds: animals affected the movement of material both in water and on land.

Dr Zareena Khan of Queen Mary University of London (QMUL) recorded average changes of 136 percent in freshwater systems.

The same evidence revealed an average change of 66 percent in terrestrial environments, showing that the finding extended far beyond a few conspicuous examples.

The difference between freshwater and land raises a further question: how do animals produce such lasting physical changes in the ground?

Changes in soil texture

Much of the effect came from repeated alterations to soil texture, particularly when animals created more space between grains.

Scientists call this space within soil or sediment porosity, and animals increased it in both environments.

Animal activity also reduced fine material by 44 percent overall, frequently leaving coarser ground in its place.

With looser ground and fewer fine particles, water entered differently and changed the way sediment and other material were moved and deposited locally.

Water, sediment mixing and erosion

After animals loosened or sorted the ground, water encountered less resistance and began to move sediment differently through streams, banks and burrows.

The study found that, in freshwater environments, particle size increased by 201 percent and sediment mixing rose by 444 percent on average.

On land, animals increased erosion by 299 percent and raised water infiltration and content by 17 percent.

These shifts help explain how a burrow, nest or disturbed riverbed can subsequently redirect floods, seepage and sediment movement.

Freshwater carries stronger marks

The average response was strongest in freshwater systems, substantially exceeding the average effect recorded on land.

Flowing water probably amplified the effects: once fish, crayfish, worms or other animals disturb grains, those grains can be carried away quickly.

Although the effects on land were still substantial, soils often kept changes nearer their source rather than allowing them to spread downstream.

This distinction matters to managers, because river restoration and flood planning may overlook a major driver when wildlife disappears.

Builders beyond beavers

Beaver dams may attract attention, but the evidence covers a much broader range of wildlife: nine animal classes, including fish, crustaceans and birds.

Material was moved through burrowing, trampling, walking, feeding and nest building, demonstrating that the effect is not dependent on one prominent species.

“Animals are constantly redistributing soils and sediments through their everyday activities,” said Dr Khan.

The evidence indicates that ordinary behaviour, repeated often enough, can alter the ground without a single dramatic event.

The impacts are not washed away

Scientists had long assumed that steep, high-energy landscapes would erase the effects of animals, leaving floods and gravity to dominate.

The analysis instead found little clear evidence that higher-energy conditions consistently weakened animal influence at freshwater or terrestrial sites.

Some effects even reversed direction with elevation, meaning that the setting influenced the type of mark animals left behind.

The map is incomplete

The paper measured 61 wild species, whereas a 2025 global census had already identified more than 600 animal taxa that shape Earth’s surface.

For many of those animals, the paired data needed to estimate the strength of their effects on land or riverbeds are still unavailable.

That gap probably directs attention towards larger or more visible animals, although less conspicuous species may carry out substantial work each day.

The current figures are therefore better understood as a minimum rather than a complete account of wildlife’s power to shape landscapes.

Protecting ecosystems from stress

Animals affect how the ground stores water and sheds sediment, so their loss can change how ecosystems respond to stress.

Freshwater habitats warrant particular attention because the strongest effects were found there and many such systems are already under pressure.

“When these actions accumulate across landscapes and over time, they can significantly influence how landscapes evolve,” Khan said.

Biodiversity loss is consequently more than a conservation issue – it can also change the landscape itself.

Animals will keep reshaping the planet

Some of the strongest effects animals have on the ground have received the least scientific attention, especially changes that prepare it for subsequent erosion.

In freshwater habitats, some of the largest changes involved the mixing and structuring of ground, but these conditioning effects have attracted limited attention.

Livestock were scarcely represented in the available evidence, with only two domestic taxa included, leaving their role largely unresolved.

Improved measurements across common species, everyday behaviours and longer timescales would reveal whether today’s totals are only the beginning.

Through ordinary, cumulative activities, animals continue to reshape the planet as routine forces in living systems rather than as rare curiosities.

Future land management will be more effective when it recognises wildlife as part of the processes that move soil, water and sediment.