Loss of largest and oldest individuals of the Montpellier snake correlates with recent warming in the southeastern Iberian Peninsula

Abstract

The effects of climate change on organisms are now being extensively studied in many different taxa. However, the variation in body size, usually shrinkage in response to increasing temperature, has received little attention regarding to reptiles. During past periods of global warming, many organisms shrank in size, and current evidence and experiments manipulating temperature have shown a biomass decrease in some organisms with increasing temperatures. Here we test whether the body size of the Montpellier snake Malpolon monspessulanus from the southeastern Iberian Peninsula is changing and correlated with the increasing temperature in this region during a 39-year period (1976–2014). We measured the snout–vent length (SVL) of vouchers in scientific collections to check for trends in adult body size at the population level in relation with temperature, while controlling for the age of the individuals (estimated by skeletochronology, n =141). Given the great ontogenetic variation in body size of the study species, we categorized age in 3 classes: “young adults” (under 5 years old), “intermediate adults” (from 5 to 7 years old), and “old adults” (from 8 to 14 years old). By means of linear mixed models, we found a negative relationship between SVL of “old adults” and average annual temperature in the region during the lifetime of each individual. Our results indicate that largest and oldest individuals of the Montpellier Snake, that is, males because of strong sexual size dimorphism in this species, disappeared from the study population, and suggest that it occurred in response to rising environmental temperature.

Northward expansion of the bivoltine life cycle of the cricket over the last four decades

“…Recent decreases in body size of ectotherms are often explained by the general negative relationship between adult body size and temperature in relation to climate warming (Gardner, Peters, Kearney, Joseph, & Heinsohn, ; Scheffers et al, ; Sheridan & Bickford, ). It was shown that increasing temperature caused decreases in the body size over several decades in butterflies (Bowden et al, ), beetles (Tseng et al, ), fishes (Baudron, Needle, Rijnsdorp, & Tara Marshall, ; Daufresne, Lengfellner, & Sommer, ), amphibians (Caruso, Sears, Adams, & Lips, ; Reading, ; Sheridan, Caruso, Apodaca, & Rissler, ), and reptiles (López‐Calderón, Feriche, Alaminos, & Pleguezuelos, ). In a frog, Lithobates sylvaticus , and a few species of salamanders, the magnitude and the direction of the body size response differed geographically, and depended on the change in temperature and precipitation (Caruso et al, ; Sheridan et al, ).…”

Recent Invaders in Small Mediterranean Islands: Wild Boars Impact Snakes in Port-Cros National Park

“…Large and presumably old individuals are essential for population viability in long-lived reptiles with indeterminate growth, notably because reproductive output and survival probability increase with body size [52]. Both snake species (M. monspessulanus and Z. scalaris) are long-lived animals (>14 years) [40] with delayed maturity and relatively low fecundity [31]. The sharp decline in M. monspessulanus snake numbers in Port-Cros is worrying, adult numbers will decrease if wild boar pressure is not relaxed, therefore entailing population collapse.…”

“…Juveniles and adults were distinguished according to their size (snout to vent length, SVL) and/or using information on their reproductive status when available (i.e., presence of eggs) [32]. The size at which individuals attain maturity varies according to species and sex, we used the following criteria: juvenile (SVL < 55 cm) in male of M. monspessulanus, and females SVL < 65 cm [40]. All individuals were rapidly released at the exact place of capture.…”

Decline in body size and female fraction in the grass snake (Natrix natrix, Linnaeus 1758) population after 40 years (Southern Poland)

“…Sexual size dimorphism may drive sex-specific decline in body size, due to higher pressure on larger specimens (López-Calderón et al 2017 ; Bury and Zając 2020 ). At the whole population level, size-biased pressure can result in changes of sex ratio.…”