Variation in life history traits of the Sahara frog (Pelophylax saharicus) with elevation and predation in northeast Algeria

Abstract

Ectotherms respond quickly to environmental change and thus are prone to show adaptive mechanisms across a gradient of environmental conditions. Frogs in particular have been widely used in experimental ecology to test life history theory and plasticity across gradients. However, little has been carried out on the North African Sahara frog (Pelophylax saharicus) which experiences a particularly stressful environment characterized by warm and dry conditions. In this study, we documented the adaptation of P. saharicus life history across elevation in northeast Algeria using six different populations spanning across a range of 5–1000 m. Based on snout-vent length (SVL) and body weight, we estimated the growth rate of tadpoles of each population in two predation treatments (presence and absence of Anax sp. dragonfly chemical cue). We found that the fastest-growing population was that at low elevation, followed by intermediate elevations and high elevation. Predation affected only low-elevation populations, increasing the rate of growth in body weight but not in SVL. Our results indicate that P. saharicus has adapted its life history to different conditions across elevation, suggesting low gene flow between low- and high-elevation populations.