Is managing horses ‘as wild’ beneficial for dung beetle assemblages and their associated ecological functions?

Overview

• This research investigates whether managing horses in a “wild” manner benefits dung beetle communities and their ecological roles by comparing dung beetle assemblages and dung decomposition rates in different grazing systems in southern France.

Background and Purpose

• In Europe, wild ungulates have largely been replaced by livestock over centuries, making dung beetle communities highly dependent on livestock grazing.
• Changes in livestock farming in the 20th century have strongly impacted these dung beetle assemblages.
• Trophic rewilding—reintroducing or managing large herbivores to mimic natural ecosystems—is increasingly used in conservation and rewilding efforts.
• Dung beetles are considered good indicators of success in rewilding efforts due to their role in dung decomposition and nutrient cycling.
• The research aims to understand how different grazing management styles affect dung beetle communities and ecological functions.

Methodology

• The study was conducted in southern France, comparing three neighboring grassland habitats:
• A population of Przewalski horses managed under natural selection (“as wild”).
• A flock of sheep managed for production.
• A herd of endurance horses also managed for production.
• Data collected included:
• Composition of the dung from each grazer species.
• Structure and diversity of the dung beetle assemblages in each area.
• Rate of dung disappearance as a measure of ecosystem function.

Key Findings

• Differences in dung composition: The dung from the three grazers showed significant compositional differences.
• Similar dung beetle species pool: Despite different dung types, the same overall set of dung beetle species was found across the habitats.
• Variations in assemblage structure: The relative abundance and functional groups of dung beetles differed between habitats.
• Tunnelers were the dominant dung beetle group in all habitats.
• Rollers were the second most abundant group in livestock-managed farms (sheep and endurance horses).
• In the Przewalski horse rangelands managed “as wild,” dwellers replaced rollers as the second most abundant group.
• Dung removal rates: Sheep droppings were decomposed more quickly than horse dung, potentially due to dung composition and associated beetle assemblages.

Implications

• The type of herbivore species and their management style shape dung beetle assemblages and influence dung decomposition rates.
• Managing horses “as wild” alters the dung beetle community structure compared to domestic farm management, which can impact ecological functions.
• These insights help refine conservation and rewilding strategies by highlighting the importance of herbivore identity and management.
• The historical context is important: in this region, dung beetle communities have a long association with sheep pastoralism, affecting their current assemblage structures.
• Further research is needed on ecological heritage and species co-occurrence to better understand these complex interactions in semi-natural European grasslands.