Large Herbivores Play a Key Role in Maintaining Tree Diversity in Protected Areas

A new study has revealed that these large herbivores, also known as megafauna, have a significant impact on the tree cover and diversity of the world's protected areas.

By browsing, grazing and trampling on vegetation, they create a mosaic of different habitats that support a variety of plant and animal species.

The study also suggests that restoring or conserving these animals could enhance the resilience and functioning of ecosystems, which are vital for biodiversity and climate change mitigation.

The role of megafauna in shaping tree cover

(Photo : ARNAUD FINISTRE/AFP via Getty Images)

Using global satellite data, a research team has mapped the tree cover of the world's protected areas.

The study shows that regions with abundant large herbivores in many settings have a more variable tree cover, which is expected to benefit biodiversity overall.

Large herbivores, such as elephants, bison, and moose are part of the megafauna, the part of the animal population in an area that is made up of the largest animals.

These animals play an important role in maintaining species-rich and resilient ecosystems, which are key to preserving biodiversity and mitigating climate change.

In a new study published in the journal One Earth, an international research team, of which Lund University is a part, has investigated the intricate interplay between the number of voracious herbivores and the diversity of trees in the world's protected areas.

"Our findings reveal a fascinating and complex story of how large herbivorous animals shape the world's natural landscapes. The tree cover in these areas is sparser, but the diversity of the tree cover is much higher than in areas without large herbivores," said Lanhui Wang, a researcher in physical geography and ecosystem science at Lund University.

The study found a substantial association between the biomass of large herbivores and varied tree cover in protected areas, notably for browsers and mixed-feeders such as elephants, bison, and moose, and in non-extreme climates.

The study supports the idea that large wild herbivores promote a diverse vegetation structure, creating a rich habitat for many other species. This is due to the animals' consumption of vegetation as well as physical disturbances.

Also Read: Extinction Of Large Herbivores May Explain Modern-Day Wildfires, Researchers Say

The need for integrating large herbivores into conservation strategies

According to Lanhui Wang, these new research findings highlight the need to integrate large herbivores into restoration and conservation strategies.

Not only for the sake of the animals themselves but also for the vital role they play in shaping landscapes and influencing biodiversity.

The researchers argue that this aspect is not sufficiently considered within the framework of sustainable land management and ecosystem restoration.

"At a time when global initiatives are intensely focused on combating climate change and biodiversity loss, our findings highlight the need for a broader and more nuanced discussion about ecosystem management and conservation measures. It is of utmost importance to integrate understanding of the ecological impact of megafauna into this," said Lanhui Wang.

The UN has declared the 2020s as the decade of ecosystem restoration. In total, 115 countries have agreed to restore up to 100,000 square kilometers of nature.

To achieve this, more wild-living large herbivores are needed worldwide, says Lanhui Wang.

The study also suggests that reintroducing or conserving large herbivores in areas where they have been extirpated or reduced could enhance tree diversity and ecosystem functioning.

However, the researchers acknowledge that this would require careful planning and management, as well as addressing potential conflicts with human activities and interests.

The study is based on data from more than 13,000 protected areas across the globe, covering about 15% of the terrestrial land surface.

The researchers used satellite imagery to measure the tree cover and its variability and combined it with data on the biomass of large herbivores from the International Union for Conservation of Nature (IUCN).

The study is part of the MegaPast2Future project, funded by the European Research Council, which aims to understand how megafauna influence the structure and functioning of ecosystems, and how this can inform conservation and restoration efforts.

Related article: Decline of Large Herbivores Could Lead to 'Empty Landscape'