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Accueil du site → Master → Mexique → Maestría → Ecología térmica y uso de microhábitat de Sceloporus hunsakeri y Sceloporus licki (Sauria : Phrynosomatidae) en la Región del Cabo Baja California Sur

Centro de Investigaciones Biológicas del Noroeste (CIBNOR) 2013

Ecología térmica y uso de microhábitat de Sceloporus hunsakeri y Sceloporus licki (Sauria : Phrynosomatidae) en la Región del Cabo Baja California Sur

Valdez Villavicencio, Jorge Heriberto

Titre : Ecología térmica y uso de microhábitat de Sceloporus hunsakeri y Sceloporus licki (Sauria : Phrynosomatidae) en la Región del Cabo Baja California Sur

Auteur : Valdez Villavicencio, Jorge Heriberto

Etablissement de soutenance : Centro de Investigaciones Biológicas del Noroeste (CIBNOR)

Grade : Maestría en Ciencias en el Uso, Manejo y Preservación de los Recursos Naturales 2013

Résumé
The genus Sceloporus is a diverse group of medium-size, insectivore, and climbing lizards. Sceloporus hunsakeri and S. licki , which have been studied little in respect to their natural and ecological history , are endemic species associated to rocky environments of the Cabo Region . S. hunsakeri and S. licki , as well as reptiles in general, are ectothermic species  ; in other words, they obtain their energy from external sources to warm up and regulate their body temperature . The majority of the physiological processes are highly sensitive to temperature, thus they have developed different ethological strategies, as thermoregulation and microhabitat use to perform their physiological survival needs. Thermoregulation and microhabitat use studies are important to understand how a species adapts to and uses its environment. In this study we compared thermal ecology and microhabitat use of S. hunsakeri and S. licki in sympatric and allopatric areas of Cape Region, Baja California Sur during dry and wet seasons. Fieldwork was performed in three study sites : (1) Rancho Casas Blancas ( S. hunsakeri ) ; (2) Cañón de San Dionisio (both species) ; and (3) Segundo Valle, Sierra de La Laguna ( S. licki ). Data of body temperatures ( T b ), operative temperatures , and microhabitat structural variables were taken in field ; in the laboratory, we obtained preferred temperatures by a thermal gradient. The results showed only S. licki in allopatry ( Segundo Valle, Sierra de La Laguna) with the lowest T b ́s (31.4 -31.8 ºC) compared to the rest of the sites in both seasons (between 33.8 ºC and 34.7ºC). Both species showed to be efficient thermoregulators in the study sites in spite of the low thermal quality of the habitat. In sympatry t hey showed similarities in microhabitat use , where we observed the majority of the individuals in rocky substrates (93-97% in S. hunsakeri and 89-95% in S. licki ), and in other very similar microhabitats in both seasons. In allopatry S. licki population showed differences in microhabitat use , showing preference to rocks and fallen logs as substrates. Daily activity in the sympatric area showed a bimodal pattern in both seasons , finding significant differences in activity hours ( P <0.05). Environmental seasonality did not show significant effects in thermal ecology, but it showed preference for certain microhabitat variables. These results showed that thermal ecology and microhabitat use were similar in sympatry in both species, and in allopatry only S. hunsakeri maintained these similarities, which makes us think that species separation in the sympatric area can be given by other factors.

Mots Clés : Sceloporus hunsakeri ; Sceloporus licki ; termorregulación ; uso de microhábitat ; patrones de actividad

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Page publiée le 21 novembre 2017, mise à jour le 26 décembre 2019