Small mammalian herbivores at moderate densities facilitate livestock growth by improving vegetation composition in grasslands.

Moderate densities of pikas (around 200 burrows/ha) enhance yak weight gain by improving vegetation composition in Qinghai-Tibetan grasslands.

• Why it matters: Understanding the interactions between small mammals and large herbivores is crucial for sustainable pasture management, especially given conflicting views on pikas as pests or keystone species.
• What they did: Field experiments manipulated pika densities and measured vegetation changes, revealing that pikas reduce poisonous Stellera plants and boost forage quality, leading to up to 42% increased yak weight gain.
• The result: Maintaining pikas at moderate levels benefits livestock growth and ecosystem health, suggesting a shift from eradication to density-based management to optimize pastoral productivity.