Trends to adaptation of the Sahara frog (Pelophylax saharicus) larvae across an environmental gradient

Abstract

Species adjust their behavior and life-history to adapt to local environmental conditions. Species with large ecological prevalence often show signatures of local adaptations to different environment, particularly in extreme ones. Here, we investigate local adaptation in different populations of the North African Sahara frog (Pelophylax saharicus) living in various environmental conditions that varies mostly in temperature, precipitation, and elevation by mean of common garden experiment aiming to estimate the growth rate under two predation treatments (absence or presence of non-lethal cues of dragon y larvae). First, we found an elevational cline in the reproductive phenology where, from low to high elevation, the reproductive season shifts to later dates, whereas that in arid environment was later than all other populations. We suggest that geographic differences in temperature and rainfall (in arid areas) explain this phenological pattern. Second, hatching success was overall high but showed a slight decline across elevation. Third, growth rate was generally faster in low and intermediate elevation populations, but slower in high elevation and arid environment populations. Populations in low and intermediate elevation responded to predation by reducing growth rate and the size at metamorphosis, but no predatory responses were recorded in high elevation and arid environment populations. Our study shows some life history signatures of local adaptation of P. saharicus in Northeast Algeria, which does not go in line with recent genetic analysis showing low population differentiation in the region.

3D Morphological Scanning and Environmental Correlates of Bufo gargarizans in the Yellow River Basin

“…The results of our study are the same as the latter's conclusions, that is, the pattern of body size variation in B. gargarizans does not follow Bergmann's rule. The UR population investigated in this study is located at a high elevation (mean elevation was 2946 m), and it is hypothesized that the increase in elevation has led to a reduction in suitable ecological niches where larger individuals may have difficulty surviving due to insufficient food supply, and thus this cold, arid environment has led to individuals allocating energy used for body growth to other processes [27,28]. This, combined with the fact that B. gargarizans migrate to terrestrial habitats after a brief reproductive period in the water [29] and that the overall cold temperatures at high altitudes result in a shorter average activity time, has collectively led to the reduction in the size of the toad and the homogenization of the size of both males and females.…”