Amphibia-Reptilia 39 (2018): 229-238 Aspects of thermal ecology of the meadow lizard (Darevskia praticola) Jelena Corovi´ c´1,∗, Jelka Crnobrnja-Isailovic´1,2 Abstract. We studied the thermal biology of the meadow lizard (Darevskia praticola) in the peripheral part of its distribution range (westernmost edge of the distribution area). We assessed whether these lizards actively thermoregulate, estimated the accuracy and effectiveness of thermoregulation, and evaluated the thermal quality of the habitat using the standard thermal parameters: body (Tb), preferred (Tpref) with set-point range (Tset) and operative temperatures (Te). Tset of the meadow lizard under controlled laboratory conditions was between 27.8°C and 31.4°C. In the field Tb and Te averaged 29.0°C and 26.1°C, respectively. A large proportion of Tes fell below the Tset range of the meadow lizard, and lizard Tbs were substantially closer to the species’ Tset range. Obtained values of thermoregulatory indices suggested that the meadow lizard thermoregulated actively, with a rather high accuracy (db = 0.8) and effectiveness (E = 0.8andde − db = 2.6), and that their habitat at this locality was thermally favourable during the spring. Our results suggest that thermal requirements of the meadow lizard resemble those of alpine lacertids, while their TbsandTset are lower than in most lacertid lizards. Further thermoregulation studies could be an important step in predicting the impact of the global climate change on the meadow lizard and the risks of local extinctions of its peripheral populations. Keywords: field body temperatures, Lacertidae, peripheral populations, preferred temperatures, thermoregulation. Introduction According to Arnold (1987), European lacer- tid lizards do not differ much regarding feed- Reptiles thermoregulate in response to differ- ing ecology, foraging strategies, activity pat- ent temperatures, which enables them to gather terns and thermoregulatory behaviour. How- and process food, avoid predators and repro- ever, given that there are noticeable differences duce, indirectly influencing their fitness by af- in the size and geographical position of their fecting physiological, reproductive and eco- ranges, some researchers consider that vari- logical performance (Huey, 1982; Adolph and ous lacertid lizards use the thermal compo- Porter, 1993; Angilletta, 2009). Many studies nents of their environment differently (Monas- have shown that lizards are able to regulate terio et al., 2009; Osojnik et al., 2013; Ortega, their body temperature in relation to differ- Mencía and Pérez-Mellado, 2016a; Sagonas et ent environmental conditions by changing be- al., 2017). Their thermoregulation activities re- haviour, activity times and selection of suitable spond to the environment but are also depen- microhabitats, which alters the rates of heat- dent on the species physiology (Huey, 1982; ing and cooling (Bauwens, Hertz and Castilla, Angilletta, 2009). For example, the ecophysi- 1996; Díaz and Cabezas-Díaz, 2004; Ortega and ology of the genus Iberolacerta, that seems to Pérez-Mellado, 2016). be restricted to the mountain tops after the last glaciation, suggests that these lizards are more adapted to the cold climatic conditions than 1 - Department of Evolutionary Biology, Institute for Bio- logical Research “Siniša Stankovic”,´ University of Bel- most Podarcis species, that have a preference grade, Despota Stefana Boulevard 142, 11000 Belgrade, for higher temperatures (Crochet et al., 2004; Serbia Monasterio et al., 2009; Ortega, Mencía and 2 - Department of Biology and Ecology, Faculty of Sci- Pérez-Mellado, 2016a,b). Because of their ec- ences and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia tothermic physiology, the distribution of reptiles ∗Corresponding author; is highly dependent on environmental temper- e-mail: [email protected] atures (Huey, 1982; Vitt and Caldwell, 2009), © Koninklijke Brill NV, Leiden, 2018. DOI:10.1163/15685381-17000218 230 J. Corovi´ c,´ J. Crnobrnja-Isailovic´ although habitat humidity also influences their have certain thermal constraints. These con- activity and distribution (Daltry et al., 1998; straints may be an extra restrictive factor for the Ferreira, Santos and Carretero, 2016; Carneiro suitable habitats of the species, especially due et al., 2017). The influence of environmental to climate change (Sinervo et al., 2010; Huey temperatures might be different at the edges of et al., 2012; Meiri et al., 2013) that is predicted the species area, because populations usually to alter the temperature and humidity patterns become smaller and more fragmented as the of habitats (making them hotter and drier). This species approach their ecological limits, which would affect the species’ response to the altered may be followed by increased genetic isolation habitat suitability. While some species have the and the loss of ability for local adaptation and potential to change their range and adapt, these range expansion (Bridle and Vines, 2007; Sex- changes may be detrimental for species with ton et al., 2009). limited dispersal ability or physiologically im- The meadow lizard (Darevskia praticola Ev- posed constraints (Araújo, Thuiller and Pear- ersmann, 1834) is a small lacertid species with son, 2006; Sinervo et al., 2010; Le Galliard et a snout-to-vent length (SVL) usually less than al., 2012; Ortega, Mencía and Pérez-Mellado, 65 mm (Arnold, 2004). It has a disjunctive dis- 2016a). tribution range (Agasyan et al., 2009; Sillero Since the knowledge on lizard thermoregula- et al., 2014) divided in two subranges: east- tory behaviour in peripheral habitats could be ern (Caucasus) and western (Eastern and South- an important step in predicting the risks of lo- eastern Europe). The western part of the range cal extinctions (Sinervo et al., 2010; Foufopou- is located in the South-eastern Europe (territory los, Kilpatrick and Ives, 2011; Lara-Reséndiz of Romania, Serbia, Bulgaria, Northern Greece et al., 2015) we investigated the thermoregula- and European part of Turkey) where the lizard tory strategy of the meadow lizard and its lo- reaches its western distribution limit near the cal temperature requirements in the peripheral Ibar river valley in Central Serbia (Uroševic´ part of the distribution range. The study local- et al., 2015). Its distribution in this part of ity is set at the westernmost edge of the species the range is quite patchy (Beshkov and Nanev, range, and it differs from the central habitats of 2006; Cogalniceanu˘ et al., 2013; Uroševicet´ the distribution in this area (eastern Serbia and al., 2015). Contrary to most members of the genus, that are saxicolous, the meadow lizard south-western Romania). Main differences can is a ground dwelling species, mostly living in be found by comparing the patterns of two ma- and around broad-leaved woodlands, but can jor climatic variables for the region – mean an- also be found in meadows with lush vegetation nual temperatures and annual precipitation, ob- (Arnold, 2004; Agasyan et al., 2009). It is cur- tained from the BioClim variables dataset (Fick rently listed as Near Threatened (NT) on the and Hijmans, 2017). This locality shows higher IUCN’s European Red List of Reptiles (Cox and mean annual temperatures and lower amounts Temple, 2009). Although being considered as of annual precipitation. Another quite signifi- a thermophilic species by Covaciu-Marcov et cant difference is the intense habitat fragmenta- al. (2009a) the meadow lizard can usually be tion caused by human activity, observable from found in rather moist and shaded places in com- Vegetation Continuous Fields (VCF) that repre- parison to other small lacertids (Arnold, 1987, sents the forest vegetation cover (Sexton et al., 2004; Strijbosch, Helmer and Scholte, 1989; 2013). This habitat alteration is a result of the Darevsky 1997; Covaciu-Marcov et al., 2009b). close proximity to the biggest city in Serbia, and Moreover, its diurnal activity can be halted dur- expansion of adjacent villages and agricultural ing particularly warm days (author’s pers. obs.). fields. Also, the lack of old oak trees, compared These facts suggest that the meadow lizard may to the more preserved habitats found in eastern Thermal ecology of the meadow lizard 231 Serbia shows a historically more intense human preferred body temperatures (a range of temperatures se- influence at this locality (author’s pers. obs.). lected by lizards in a laboratory thermal gradient in the ab- sence of other ecological constraints) that are usually de- In the study we applied the experimental pro- scribed using a set-point range – Tset.DataonTb and Te tocol designed by Hertz, Huey and Stevenson values were simultaneously collected in the field to provide (1993), which has been widely used in studies of the same general temperature conditions for both lizards and thermal ecology of lizards to determine whether models, enabling their later comparison. they actively thermoregulate, to estimate accu- Body temperatures racy and effectiveness of thermoregulation, and to evaluate the thermal quality of the habitat Active adult meadow lizards were captured by noose or by hand (n = 53) and sexed on the basis of body shape, (Díaz, 1997; Monasterio et al., 2009; Pafilis et size of femoral pores and presence/absence of hemipenises. al., 2016; Sagonas et al., 2017). Our goals were: Additionally, SVL and weight of the studied lizards were (1) to determine whether these lizards actively measured. Body temperature (Tb) was measured at the cloaca