ECOLOGÍA TÉRMICA DE UNA POBLACIÓN DE LA LAGARTIJA SCELOPORUS GRAMMICUS (IGUANIDAE: PHRYNOSOMATINAE) QUE OCURRE EN LA ZONA CENTRO-ORIENTE DE LA CIUDAD DE MÉXICO

The thermal ecology of the lizard, Sceloporus grammicus in Mexico City was studied. Mean body temperature (Tb) was 31.43 ± 0.1 ºC. Body temperature was significantly and positively related to air temperature (Ta: n = 147, r = 0.451, P < 0.001; Tb = 27.529 + 0.195 Ta) and substrate temperature (Ts: n = 147, r = 0.482, P < 0.001; Tb = 27.315 + 0.199 Ts) occupied by the lizards. The body temperature was different between males and females (ANCOVA with Ts as the covariate F1,146 = 8.71, P = 0.003) and between pregnant females and unpregnant females as well (ANCOVA with Ts as the covariate F1,91 = 18.81 P < 0.001). These results suggested that S. grammicus is a lizard with active thermoregulation and that reproductive status can influence the thermoregulatory strategy of females.Estudiamos la ecología térmica de la lagartija Sceloporus grammicus que habita en la región central de la Ciudad de México. La temperatura corporal (Tc) promedio para estos organismos fue de 31.43 ± 0.1 °C. La Tc de Sceloporus grammicus estuvo positiva y significativamente correlacionada con la temperatura del aire [Ta] (n =147, r = 0.451, P < 0.001; Tc 27.529 + 0.195 Ta) y con la temperatura del sustrato [Ts] (n = 147, r = 0.482, P < 0.001; Tc = 27.315 + 0.199 Ts) donde se encontraban. Observamos diferencias significativas entre la temperatura corporal de machos y hembras (ANCOVA con la Ts como covariable F1,146 = 8.71, P = 0.003), así como en la temperatura corporal presentada entre hembras preñadas y no preñadas (ANCOVA con la Ts como covariable F1,91 = 18.81 P < 0.001). Estos resultados sugieren que S. grammicus presenta una tendencia hacia la termorregulación activa y que el estadio reproductivo de las hembras puede influir su estrategia termorreguladora

Temporal variation in the abundance and distribution of poeciliopsis fasciata in near-shore habitat of the high elevation lake, lago de achichilca, puebla, mexico

The distribution of organisms within a pond or lake can reflect the result of a variety of factors. We examined the distribution and abundance of the fish, Poecilioposis fasciata, in Lago de Achichilca, Puebla, Mexico, as well as how the distribution and abundance varied among months. Dissolved oxygen, temperature, and salinity varied among months. The abundance of P. fasciata peaked in December and February. For the months when fish were observed, their abundances were positively related to dissolved oxygen concentration and were generally not related to temperature. Our results make it clear that there is substantial seasonal variation in the abundances of P. fasciata and that within months, their distributions are likely driven more by dissolved oxygen than either temperature or salinity

Thermoregulatory strategies of three reclusive lizards (genus Xantusia

The thermal quality of the habitat is key for the regulation of body temperature in terrestrial ectotherms and, therefore, permits them to carry out their fundamental biological activities. In thermally heterogeneous environments, ectotherms might follow different behavioral or physiological strategies to maintain their body temperature within biologically adequate boundaries, for which they depend on microhabitat selection. These aspects are, thus, relevant in the context of habitat degradation and land-use change. In this study, we characterized the thermal ecology of three lizard species (genus Xantusia) that differ in microhabitat use along the Baja California peninsula, Mexico. We made three predictions: (1) the three species will follow different thermoregulatory strategies according to habitat thermal quality; (2) the thermal requirements and tolerances of these species will match the environmental or microenvironmental thermal conditions; and (3) due to their habitat and range restriction, the species studied will be highly vulnerable to climate change. Our results indicate the existence of thermoregulatory mechanisms in Xantusia to face thermal heterogeneity, including behavioral thermoregulation by choosing different microhabitats, shifts in activity periods, and adaptation to particular high thermal quality microhabitats. Furthermore, despite their association to specific microhabitats and specialized physiology, the studied species will not be adversely affected by climate change, as the increased microenvironmental temperatures will lead to a higher habitat thermal quality and lower costs of thermoregulation. However, we do not discard other indirect adverse effects of climate change not considered in this study.Fil: Arenas Moreno, Diego M.. Universidad Nacional Autónoma de México; MéxicoFil: Lara Resendiz, Rafael Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Domínguez Guerrero, Saúl F.. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Delgadillo, Ana G.. Universidad Nacional Autónoma de México; MéxicoFil: Muñoz Nolasco, Francisco J.. Universidad Nacional Autónoma de México; MéxicoFil: Galina Tessaro, Patricia. Centro de Investigaciones Biologicas del Noroeste; MéxicoFil: Méndez de la Cruz, Fausto R.. Universidad Nacional Autónoma de México; Méxic

Harnessing cross-border resources to confront climate change

The US and Mexico share a common history in many areas, including language and culture. They face ecological changes due to the increased frequency and severity of droughts and rising energy demands; trends that entail economic costs for both nations and major implications for human wellbeing. We describe an ongoing effort by the Environment Working Group (EWG), created by The University of California's UC-Mexico initiative in 2015, to promote binational research, teaching, and outreach collaborations on the implications of climate change for Mexico and California. We synthesize current knowledge about the most pressing issues related to climate change in the US-Mexico border region and provide examples of cross-border discoveries and research initiatives, highlighting the need to move forward in six broad rubrics. This and similar binational cooperation efforts can lead to improved living standards, generate a collaborative mindset among participating universities, and create an international network to address urgent sustainability challenges affecting both countries