Name: Ferreira C

Biodeserts supervisors: Santos X

Co-supervisor:  Carretero MA

Title: Contrast on ecophisiological performace of reptiles according to their responses to fire

Institution: University of Porto

Status: Concluded

 

Abstract

 

Reptiles are known to be sensitive to habitat disturbance, including fires. However, evidence from systematic monitoring suggests that reptile species show opposing responses to fire. In particular, in a contact zone between Mediterranean and Atlantic bioregions in Northern Portugal, field transects indicate that Mediterranean lizard species (i. e. Timon lepidus, Psammodromuns algirus and Podarcis guadarramae) increase in abundance in burnt areas whereas Atlantic lizard species (i. e. Lacerta schreiberi and Podarcis bocagei) decrease. Here we test if such differences across species are of functional nature, namely, whether thermal and hydric ecophysiology may determine their response to fire. The habitat structure greatly differs between unburnt and repeatedly-burnt sites. For this reason, we hypothesise that Mediterranean reptiles that increase density in open habitats promoted by frequent fire regimes should be more thermophile and suffer lower water loss rates than those negatively affected by fire. We collected 8-10 adult males of each five lizard species and measured their body mass (BM) and length (SVL). We then submitted lizards to standard experiments for assessing preferred body temperatures (Tp) and evaporative water loss rates (EWL), and examined the variation of both parameters among species and along time by means of repeated-measures AN(C)OVAs. Results only partially supported our initial expectations. As expected, the medium sized P. algirus clearly attained higher Tp and lower EWL. The two small species (P. bocagei and P. guadarramae) displayed low Tp and high EWL while the two large species (T. lepidus and L. schreiberi) displayed intermediate values. However the predictions of finding differences within each pair were not confirmed. Moreover, although EWL decreased with lizard size within species, results between species remained similar after introducing lizard size as covariate in the analyses. We conclude that ecophysiology may help to understand reptile responses to fire but other life-history traits like habitat selection are to be considered as well.