Food choice of an Algerian population of the spur‐thighed tortoise, Testudo graeca

Abstract

The diet of an Algerian population of spur‐thighed tortoise (Testudo graeca) was studied with the aims of exploring: (i) the variation in diet among males, females and juveniles, (ii) the relationships between consumption and relative availability of the plant species, and (iii) which plant tissues, vegetative or reproductive, are eaten by tortoises. We recorded more than forty plant species at the study area, with monocot species (n = 7) having a greater percent cover than that of dicot species (n = 31 species) or Gymnospermae (n = 2). Tortoise diet was studied by categorising 4422 plant and animal fragments in faecal pellets of 20 males, 16 females and eight juveniles. Tortoises ate a wide variety of plant species, including 13 dicots and three monocots, and occasionally invertebrates. The number of fragments for a plant species was correlated with plant species cover, and plant vegetative tissues exceeded plant reproductive tissues in the faeces. Dicots (Fabaceae, Composeae, Primulaceae, and Caryophyllaceae) accounted for over 70% of the diet (faecal fragments). The high dietary (niche) overlap, and null model analysis (RA3 algorithm with 30,000 Monte Carlo simulations), indicate that males, females and juveniles did not partition food resources; all three groups ate the same plant species.