earth

• The diminutive Karoo dwarf tortoise may play a key role in seed dispersal of plant species in its semidesert habitat in South Africa, a new study finds.
• A germination trial showed the tortoises transport seeds to microsites suitable for germination, a potentially vital means for plants to survive drought in the arid Karoo region.
• The dwarf tortoise is highly endangered due to degradation of its habitat and increased predation by ravens and crows accompanying expanded human presence in the Karoo.
• The findings underline the broader ecological roles that small, understudied species play in landscapes.

The diminutive Karoo dwarf tortoise (Chersobius boulengeri) may play an outsized role as gardener in its arid South African habitat. Researchers gathered droppings of the miniature species — this endangered tortoise is one of the world’s smallest, maxing out at 11 centimeters (4.3 inches) in length — and analyzed them to identify its preferred diet. The newly published research suggests that the tortoises’ dietary preferences may play an important role in seed dispersal of at least four plant species.

C. boulengeri is a cryptic species endemic to South Africa’s Karoo, a vast semidesert area covering around 500,000 square kilometers (193,000 square miles), a region larger than California. Studying the species is challenging because these small tortoises spend most of the day hidden motionless in rock crevices, necessitating long hours peering under rock after rock to spot their tiny camouflaged shells, according to Victor Loehr, first author of the paper, published in the Journal of Arid Environments.

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