Body temperature affects physiological processes and, consequently, has a large impact on fitness. Lizards need to thermoregulate behaviourally to maintain their body temperature within a range that maximizes performance, but there are costs associated with thermoregulation. The thermal quality of an environment is a major cost of thermoregulation because it directly affects the time and energy that must be invested by an individual to achieve and maintain an optimal body temperature for performance. According to the cost-benefit model of thermoregulation, lizards should only thermoregulate when the benefits outweigh the costs of doing so. Thus, in habitats of poor thermal quality, individuals should thermoregulate less. Using two systems, an elevational gradient and a pair of habitats that vary in the amount of solar radiation they receive, I tested the hypothesis that investment in thermoregulation by lizards is dictated by the associated costs of thermoregulating. Temperature, and thus thermal quality, decreases with elevation. I found a significant positive relationship between elevation and effectiveness of thermoregulation of Yarrow’s spiny lizards (Sceloporus jarrovii). When comparing thermoregulation of ornate tree lizards (Urosaurus ornatus) living in the thermally superior open-canopy wash habitat or the closed-canopy upland habitat, I found that habitat type was a significant predictor of accuracy of body temperature. In the poorer quality habitat, lizards had smaller deviations of body temperature from their preferred temperature range. Overall, I conclude that the thermal quality of a lizards’ environment impacts their thermoregulation in the opposite direction than predicted by the cost-benefit model of thermoregulation. This suggests that the disadvantages of thermoconformity may be greater than the costs thermoregulating as habitats become more thermally challenging.

Submitted by Priscilla Lacerda Duarte David null (pridavid@gmail.com) on 2016-04-18T17:32:38Z No. of bitstreams: 1 DISSERTAÇÃO.pdf: 3221424 bytes, checksum: eae44cc8b6d04e771aaafa4496e5e231 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-19T14:16:13Z (GMT) No. of bitstreams: 1 david_pld_me_bauru.pdf: 3221424 bytes, checksum: eae44cc8b6d04e771aaafa4496e5e231 (MD5) / Made available in DSpace on 2016-04-19T14:16:13Z (GMT). No. of bitstreams: 1 david_pld_me_bauru.pdf: 3221424 bytes, checksum: eae44cc8b6d04e771aaafa4496e5e231 (MD5) Previous issue date: 2016-02-19 / Essa pesquisa investiga as relações entre a qualidade térmica dos espaços de transição com os seus atributos físicos e condições térmicas do entorno imediato, a partir de levantamentos microclimáticos em oito espaços de transição do tipo linear externo e nos espaços internos e externos a eles associados, em condições de tempo quente. Os espaços escolhidos estão inseridos em um ambiente universitário na cidade de Bauru-SP e, por estarem localizados em edifícios de salas de aula, constituem em importantes ambientes de convívio de estudantes. Para verificar a influência dos atributos projetuais, foram definidos parâmetros de avaliação (intensidade da radiação solar incidente, obstrução do entorno, relação altura (H) e largura (W) e desempenho térmico da cobertura) e indicadores para cada um desses quatro parâmetros (de peso 0,25), distribuídos em um escala semântica variando de 0-péssimo, 0,25-ruim, 0,50-regular, 0,75-bom e 1-ótimo. Assim, foi criada uma metodologia para avaliar a qualidade térmica dos espaços de transição do tipo linear externo, que foi aplicada aos espaços estudados, para identificar quais parâmetros contribuem positiva ou negativamente para a qualidade térmica de cada. Essa metodologia permite elencar os melhores indicadores para uma avaliação positiva para os espaços de transição e os que devem ser evitados. No entanto, a qualidade microclimática dos ambientes externos adjacentes aos de transição são decisivos para uma ótima avaliação térmica. Os resultados evidenciam que a qualidade térmica dos espaços de transição é influenciada por alguns atributos projetuais e também pelas características de obstrução do entorno, além da qualidade microclimática do entorno imediato. A pesquisa também comprovou o papel amenizador microclimático e das condições de conforto térmico, calculados por meio do índice PET e, assim, reforçou resultados obtidos em estudos abordados na revisão bibliográfica. Espera-se que essa pesquisa possa contribuir para subsidiar intervenções projetuais nos espaços avaliados; contribuir para o projeto de novos espaços de transição, além de incentivar o desenvolvimento de estudos similares em outros contextos climáticos e em diferentes condições de tempo. / This research investigates the relationship between the thermal quality of transitional spaces and their physical attributes, and the thermal conditions of their immediate surroundings. The study was based on microclimatic data monitoring conducted in warm weather conditions in eight linear, external transitional spaces, and in the internal and external spaces associated with them. The spaces selected are located at a university setting in the city of Bauru-SP; and because they are within classroom buildings, these spaces represent important environments for student interaction. In order to verify the influence of project attributes, evaluation parameters (solar radiation intensity, obstruction of surroundings, height (H) and width (W), and thermal performance of the roof), and indicators for each of these four parameters were set and distributed in a semantic scale that varied from 0-very bad, 0.25-bad, 0.50average, 0.75-good, to 1-very good. This way, a methodology was created to evaluate the thermal quality of linear external transitional spaces, and applied to the spaces studied to identify which parameters contribute positively or negatively to the thermal quality of each one. This methodology allows for the classification of the best indicators, as well as the ones that should be avoided, for a positive evaluation of the transitional spaces. The results reveal that the thermal quality of transitional spaces is influenced not only by some project attributes but also by obstruction of surroundings characteristics, and by the microclimatic quality of the immediate surroundings. This research also proved the mitigating roles of microclimatic and thermal comfort conditions, which were calculated using the PET index, thereby reinforcing the results obtained in studies addressed in the bibliographic review. It is expected that this research will contribute to subsidizing project interventions in the spaces evaluated, and projects of new transitional spaces, in addition to promoting the development of similar studies in other climatic contexts, and in different weather conditions.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Thermal ecology is a central theme in reptilian biology because of the thermodynamic rate dependence of virtually all biological processes in these ectothermic animals. Thermoregulation includes active processes (with associated energetic costs related to altered behaviour and physiology) functioning to maintain body temperatures within a preferred temperature range, so that the majority of physiological functions occurs optimally, despite natural variation in the animal’s thermal habitat. The recent development of quantitative thermal indices now allows researchers to describe the thermal habitat and thermoregulatory functioning of an ectotherm within its environment from a cost-benefit perspective. The use of such quantitative biophysical approaches to reptile thermal ecology studies is however limited in the African context. Cordylus cataphractus is one of the best studied cordylids, and exhibits various characteristics atypical for the family, such as permanent group-living, seasonally lowered surface activity, a low resting metabolic rate and large fat bodies. These characteristics are generally thought to be associated with groupliving in a semi-arid habitat, yet, the possible links to thermal ecology remains unexplored. The objectives of the current study was: firstly, to characterize the preferred temperature range (Tp) of C. cataphractus through the use of ecologically realistic laboratory thermal gradients; secondly, to explore seasonal and geographical variation in thermal preference, by comparing Tp among individuals captured from a coastal and inland population and during different seasons (autumn and spring); thirdly, to describe the thermal habitat of a C. cataphractus population during summer, autumn, winter and spring and to then relate these findings to the seasonal activity patterns reported in literature for the species; fourthly, to describe the seasonal patterns of thermoregulation (during summer, autumn, winter and spring) in a C. cataphractus population through quantitative thermoregulatory indices; fifthly, to assess geographic variation in the thermal habitat and IV associated patterns of thermoregulation in C. cataphractus among a coastal population (western range limit) and an inland population (eastern range limit). The thermal habitat of C. cataphractus was described by measuring operative environmental temperatures (Te) with hollow copper lizard models placed around rocks according to the natural surface movement patterns of the species. Variation in thermal habitat quality was subsequently calculated (de = |Te – Tp|) and averaged. Field body temperatures (Tb) of lizards were measured with dorsally attached miniature temperature loggers. Thermoregulatory indices were calculated from Te, Tb and Tp, describing: thermoregulatory accuracy, the effectiveness of thermoregulation and thermal exploitation for each population (coastal and inland) for the respective sampling periods. The preferred body temperature range of C. cataphractus is the lowest recorded among cordylids to date (mean Tp = 29.8oC) and was conserved among different populations and within these populations among seasons, despite the fact that environmental temperatures are known to vary geographically and seasonally. Thermal habitat quality varied significantly at micro spatial scale around rocks in the coastal population. Since C. cataphractus males are territorial, competition for thermal habitat quality around rocks may therefore occur. Such effects will be a function of the time of year since the variability in thermal habitat quality among rock aspects (around rocks) varied seasonally. Thermal habitat quality of crevices varied among seasons and was typically higher in the open, outside rock crevices, during the cooler winter and spring periods, whereas in summer and autumn the crevice environments were more favourable. Thermal habitat quality was high in crevices during autumn, suggesting that the observed repressed surface activity of C. cataphractus described for the time is not necessarily, as previously thought, only due to food constraints. Moreover, in contrast to earlier reports, the current results (Tb versus Te) indicate that individuals emerged from crevices in summer. The geographical assessment indicated that lizards from the coastal population, with generally larger groups, thermoregulated more successfully than those from the inland population. The higher thermoregulatory success in the coastal population occurred in spite of the fact that thermal habitat quality was significantly lower at the coastal locality. The higher thermoregulatory success in the coastal population was likely due to reduced predation risk associated with increased group-size. The seasonal trends in thermoregulation at the coastal and inland population corresponded to the patterns predicted by the cost-benefit model of thermoregulation, accuracy of thermoregulation and the effectiveness of thermal exploitation being higher during the thermally more favourable autumn. / AFRIKAANSE OPSOMMING: Uittreksel Termiese ekologie is ‘n sentrale tema in reptiel-biologie as gevolg van die termodinamies tempo-afhanklikheid van feitlik alle biologiese prosesse in hierdie ektotermiese diere. Termoregulering sluit aktiewe prosesse (wat lei tot energie-koste in terme van gedrag en fisiologie) in om liggaamstemperature binne ‘n vasgestelde voorkeurtemperatuur-reeks te handhaaf sodat fisiologiese prosesse optimaal kan geskied te midde van natuurlike variasie in die dier se termiese omgewing. Die onlangse ontwikkeling van kwantitatiewe funksionele termiese indekse stel navorsers nou in staat om die werklike termiese omgewing en die funksionering van die ektoterm binne sy omgewing te beskryf en uit ‘n koste (energie)- voordeel oogpunt te verstaan. Die gebruik van hierdie biofisiese koste-voordeel benadering in reptiel termoreguleringstudies is egter beperk in die Afrika-konteks. Cordylus cataphractus is een van die bes bestudeerde lede van familie Cordylidae, en vertoon verskeie eienskappe ongewoon vir hierdie groep akkedisse, soos groeplewendheid, beperkte seisoenale aktiwiteit buite hul skeure, ‘n relatiewe lae rustende metaboliese tempo en relatiewe groot vetliggame. Hierdie unieke eienskappe is al deur navorsers gekoppel aan die groeplewe lewensstrategie. Die potensiële koppeling van die termiese ekologie en die spesifieke lewensstrategie van C. cataphractus benodig verdere studie. Die doelwitte van hierdie studie was eerstens: om die voorkeurtemperatuur-reeks (Tp) van C. cataphractus te bepaal deur van ekologies-realistiese termiese gradiënte in die laboratorium gebruik te maak; tweedens: om geografiese en seisoenale variasie in Tp te ondersoek deur individue te gebruik wat uit binnelandse en kus-populasies, tydens verskillende seisoene, herfs en lente versamel is; derdens: om die termiese omgewing, meer spesifiek die variasie in termiese kwaliteit, binne die habitat van C. cataphractus populasie in verskillende seisoene, somer, herfs, winter en lente, te moduleer en met die gedokumenteerde aktiwiteitspatrone in verband te bring; vierdens: om die seisoenale temoreguleringspatrone (tydens somer, herfs, winter en lente) van C. cataphractus populasie te beskryf; vyfdens: om geografiese variasie in die termiese habitat en geassosieerde termoreguleringspatrone tussen kus-populasie (westelike VII verspreidingsgrens) en binneland-populasie (oostelike verspreidingsgrens) te bestudeer. Die kwaliteit van die termiese habitat van C. cataphractus is bepaal deur hol koper-modelle van akkedisse (operatiewe temperatuur modelle (Te)) te plaas rondom rotse in ooreenstemming met die natuurlike bewegingspatrone van die akkedisse. Die termiese kwaliteit is gevolglik afgelei (de = |Te – Tp|) en gemiddeldes bereken. Die liggaamstemperature (Tb) van vrylopende akkedisse in die veld is met dorsaal-gemonteerde miniatuur temperatuur “data-loggers” gemeet. Termiese indekse (deur Te, Tb en Tp te gebruik) is bereken om die akkuraatheid en effektiwiteit van termoregulering, sowel as termiese benutting van die omgewing vir beide populasies (kus en binneland) tydens verskillende seisoene te beraam. Die voorkeurtemperatuur-reeks van C. cataphractus is die laagste gedokumenteerde temperature vir enige lid van die familie Cordylidae tot op hede bestudeer (gemiddeld van Tp = 29.8oC), en het ten spyte van die feit dat omgewingstemperature wissel op geografiese en seisoenale vlakke, min gevarieer tussen die twee populasies asook tydens verskillende seisoene binne die populasies. Die termiese kwaliteit het beduidend gevarieer tussen seisoene en binne die mikroruimtelike omgewing rondom rotse in die kus-populasie. Aangesien C. cataphractus mannetjies territoriaal is, word die aanname gemaak dat kompetisie vir ‘n ruimtelike posisie ook ‘n termiese koste mag hê aangesien daar beduidende variasie in de om die rotse was. Variasie in termiese kwaliteit rondom rotse was verder ook funksie van die tyd van die jaar (seisoene). Die termiese kwaliteit van skeure het gevarieer tussen seisoene, en termiese kondisies/toestande was oor die algemeen meer gunstig buite die rots-skeure tydens die koeler winter en lente tydperke, terwyl skeure termies meer gunstig was in die somer en herfs maande. Termiese habitat kwaliteit van skeure was besonders hoog gedurende die herfs, en die voorspelling is dus dat die verlaagde oppervlak-aktiwiteit wat gedurende hierdie tyd van die jaar vir C. cataphractus gedokumenteer is nie noodwendig funksie van beperkte voedselbeskikbaarheid is nie. Teenstrydig met gepubliseerde aktiwiteitsrekords dui die resultate (Tb teenoor Te) verder daarop dat individue wel uit skeure kom tydens die warm somer seisoen. Die geografiese ondersoek het gewys dat akkedisse van die kus-populasie (wat gewoonlik uit groter groepe bestaan), meer akkuraat getermoreguleer het as akkedisse van die binneland-populasie. Die hoër akkuraatheid van termoregulering in die kus-populasie is bewerkstellig ten spyte van die feit dat die termiese kwaliteit beduidend laer was as die van die binneland-populasie. Die hoër termoreguleringsakkuraatheid in die kus-populasie kan waarskynlik toegeskryf word aan laer predasie-risiko geassosieer met groter groepe. Die seisoenale variasie-patroon van termoregulering kan verklaar word deur die koste-voordeel model van termoregulering, waarvolgens die akkuraatheid van termoregulering sowel as termiese benutting hoër is tydens periodes van hoë termiese kwaliteit (i.e. herfs).