Loss of Large Herbivores Changes Dik-Dik Foraging in Kenyan Savannas

​When Large Herbivores Disappear, A Tiny Antelope Reshapes Savannas

A new study from the Kartzinel Lab and collaborators shows how the disappearance of large herbivores from African savannas causes smaller browsers to change where and how they forage—with ripple effects that reshape plant communities.

Published in the Journal of Mammalogy, the paper examines how Guenther’s dik-dik (Madoqua guentheri), a tiny antelope common in East African savannas, responds to the experimental removal of larger herbivores in Kenya. Using a combination of long-term field experiments and dietary DNA metabarcoding, the team found that dik-dik became more active, shifted their diets, and increased pressure on their preferred woody plants in the absence of larger competitors like elephants and giraffe.

The takeaway: losing large herbivores may trigger ecological changes both directly with the loss of these important consumers and also as the remaining species begin behaving differently in response.

The the publication was featured as the Cover Article and Editor's Choice in the latest issue of the journal.

Kartzinel Lab publication led by Reed et al. was featured as the Editor's Choice and Cover Article in the May 2026 issue of Journal of Mammalogy

A small antelope that has outsized ecological importance

Dik-dik are among the smallest antelope in Africa—about the size of a house cat and weighing in at only about 5 kg. But across semi-arid Kenyan savannas, they are also among the most abundant mammalian browsers and that makes them an important species for understanding how plant-herbivore interactions respond to human impacts.

In a study led by the Kartzinel Lab, a team of researchers based at Mpala Research Centre in Kenya analyzed a novel type of data emerging from the UHURU experiment, which is a long-running herbivore exclusion experiment. This experiment allows scientists to compare plots with the full herbivore community to plots where larger herbivores have been excluded.

The team paired long-term observations emerging from this experiment with novel DNA-based dietary analyses. Specifically, the team sequenced plant DNA recovered from dik-dik dung to identify what individual animals were eating and how it changed according to site and season. The team then linked those dietary profiles to field data quantifying plant abundance, nutritional quality, and anti-herbivore defenses such as the density of spines and concentration of unpalatable tannins inside leaves.

What the study revealed about the loss of large wildlife

The key finding is that that dik-dik emerged as are highly flexible browsers—their foraging flexibility shapes the trajectory of ecosystem change. Specifically, the team found:

• Dik-dik diets differed significantly from those of larger browsers, as elephants and impala.
  
• Dik-dik activity more than doubled when larger herbivores were excluded, suggesting release from competition.
  
• In the absence of larger herbivores, dik-dik diets shifted toward more nutritious and easier-to-eat / less-defended plant species.
  
• Dietary shifts were strongest in dry seasons and at more arid sites, indicating that responses become more extreme when food is more limited.
  
• Dik-dik suppressed the growth of saplings of a preferred tree species, Acacia mellifera, especially in the drier site.
  

Together, these findings suggest the ecological consequences of defaunation depend not just on which species are lost, but on how the surviving species respond to the new challenges and opportunities that novel ecosystems present.

Why it matters

Large herbivores shape the structure and function of savanna ecosystems in dramatic ways: they consume large amounts of vegetation, alter the diversity and distribution of trees, and influence habitat availability for many other organisms. This study highlights a subtler pathway of change: when the largest animals are lost from ecosystems they leave behind populations of smaller herbivores may shift their behavior enough to amplify and extend the long-term trajectories of ecosystem change.

When large herbivores disappear, smaller browsers like dik-dik can be expected to change their behaviors in ways that reshape which plants survive and thrive in these novel ecosystems."
​—Tyler Kartzinel

This subtle pathway for environmental change was especially clear under resource-limited conditions. In dry seasons and more xeric environments, dik-dik showed the strongest dietary shifts and the greatest impacts on preferred browse. This suggests that the effects of defaunation may be particularly pronounced in places already under environmental stress—a particularly important result as increasing drought frequency and intensity are expected to be characterize the impacts of anthropogenic climate across East Africa.

Ultimately, the loss of large herbivores redistributes herbivore pressures in ways that alter plant recruitment and reshape long-term vegetation diversity.

Powerfully combining field ecology and genomics

The paper demonstrates the value of combining long-term ecological experiments with modern molecular tools. Directly observing the diets of small, selective, and often elusive herbivores can be difficult. Dietary DNA metabarcoding makes it possible to reconstruct those diets in fine detail and compare them across environmental conditions.

By pairing these methods with a replicated field experiment, the team was able to move beyond simply describing patterns in order to directly test how the absence of large herbivores changes the foraging behaviors of others.

Broader impacts in conservation

Across much of Africa, large herbivore populations are under pressure from habitat loss, fragmentation, and other causes of human-wildlife conflict. Understanding what happens as iconic species like elephants decline across their historic range is essential for predicting the future of savanna ecosystems.

This study suggests that smaller browsers may not function as simple replacements for larger herbivores as their populations grow in the absence of their competitors. Instead, their responses may fundamentally reshape ecosystems and redirect the trajectory of environmental change, especially in under dry conditions where palatable plant resources are most limited.

Protecting large herbivores is thus about more than our love for charismatic megafauna as it becomes about tool we can use to help preserve the interactions that underpin the biodiversity of entire ecosystems.

Reed et al. Experimental defaunation alters foraging behavior of a small antelope (Guenther’s Dik-dik, Madoqua guentheri) in Kenya. Journal of Mammalogy (2026)
https://doi.org/10.1093/jmammal/gyag030

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