Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil

We investigated the following aspects of the biology of a population of Cnemidophorus vacariensis Feltrim & Lema, 2000 during the four seasons: thermal biology, relationship with the thermal environment, daily and seasonal activity, population structure and growth rate. Cnemidophorus vacariensis...

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Main Authors: Rodrigo Caruccio, Renata Cardoso Vieira, Laura Verrastro, Denise Mello Machado
Format: Article
Language:English
Published: Fundação Zoobotânica do Rio Grande do Sul 2011-12-01
Series:Iheringia: Série Zoologia
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212011000300002&lng=en&tlng=en
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spelling doaj-b4e4a887dad24ae2b72773e59a3fcc5d2020-11-24T23:08:17ZengFundação Zoobotânica do Rio Grande do SulIheringia: Série Zoologia1678-47662011-12-01101428329510.1590/S0073-47212011000300002S0073-47212011000300002Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern BrazilRodrigo Caruccio0Renata Cardoso Vieira1Laura Verrastro2Denise Mello Machado3Universidade Federal do Rio Grande do SulUniversidade Federal do Rio Grande do SulUniversidade Federal do Rio Grande do SulUniversidade Federal do Rio Grande do SulWe investigated the following aspects of the biology of a population of Cnemidophorus vacariensis Feltrim & Lema, 2000 during the four seasons: thermal biology, relationship with the thermal environment, daily and seasonal activity, population structure and growth rate. Cnemidophorus vacariensis is restricted to rocky outcrops of the "campos de cima da serra" grasslands on the Araucaria Plateau, southern Brazil, and is currently listed as regionally and nationally threatened with extinction. Data were collected from October 2004 through September 2007 in the state of Rio Grande do Sul. Sampling was conducted randomly from 08:00 a.m. to 6:00 p.m. The capture-mark-recapture method was employed. The lizards were captured by hand, and their cloacal temperature, sex, snout-ventral length (SVL), mass, and the temperature of their microhabitat (substrate temperature and air temperature) were recorded. Individuals were then marked by toe-clipping and released at the site of capture. Body temperatures were obtained for 175 individuals, activity data for 96 individuals, and data on population structure and growth for 59 individuals. All data were obtained monthly, at different times of the day. Cnemidophorus vacariensis average body temperature was 23.84ºC, ranging between 9.6 and 38.2ºC. Temperatures ranged between 21 and 29ºC. The correlation between external heat sources, substrate and air were positive and significant and there was a greater correlation between lizard's temperature and the temperature of the substrate (tigmothermic species). The relatively low body temperatures of individuals are associated with the climate of their environment (altitude up to 1,400 m), with large variations in temperature throughout the day and the year, and low temperatures in winter. The average body temperature observed for C. vacariensis was low when compared with that of phylogenetically related species, suggesting that the thermal biology of this species reflects adaptations to the temperate region where it lives. The monthly rates of activity of lizards were related to monthly variations in the ambient temperatures. Our data suggest that the daily and seasonal activity of C. vacariensis result from the interaction between two factors: changes in the environment temperature and the relationship between individuals and their thermal environment. The population structure of C. vacariensis varied throughout the study period, with maximum biomass in January and maximum density in February (recruitment period). The sex ratio diverged from the expected 1:1. The growth analysis showed a negative relationship between the growth rate of individuals and the SVL, revealing that young individuals grow faster than adults, a typical pattern for short-lived species. The population studied showed a seasonal and cyclical variation associated with the reproductive cycle. The life strategy of C. vacariensis seems to include adaptations to the seasonal variations in temperature, typical of its environment.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212011000300002&lng=en&tlng=enTemperatura corpóreacrescimentodensidade-biomassaregião temperadatigmotermia
collection DOAJ
language English
format Article
sources DOAJ
author Rodrigo Caruccio
Renata Cardoso Vieira
Laura Verrastro
Denise Mello Machado
spellingShingle Rodrigo Caruccio
Renata Cardoso Vieira
Laura Verrastro
Denise Mello Machado
Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil
Iheringia: Série Zoologia
Temperatura corpórea
crescimento
densidade-biomassa
região temperada
tigmotermia
author_facet Rodrigo Caruccio
Renata Cardoso Vieira
Laura Verrastro
Denise Mello Machado
author_sort Rodrigo Caruccio
title Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil
title_short Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil
title_full Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil
title_fullStr Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil
title_full_unstemmed Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil
title_sort thermal biology, activity, and population parameters of cnemidophorus vacariensis (squamata, teiidae), a lizard endemic to southern brazil
publisher Fundação Zoobotânica do Rio Grande do Sul
series Iheringia: Série Zoologia
issn 1678-4766
publishDate 2011-12-01
description We investigated the following aspects of the biology of a population of Cnemidophorus vacariensis Feltrim & Lema, 2000 during the four seasons: thermal biology, relationship with the thermal environment, daily and seasonal activity, population structure and growth rate. Cnemidophorus vacariensis is restricted to rocky outcrops of the "campos de cima da serra" grasslands on the Araucaria Plateau, southern Brazil, and is currently listed as regionally and nationally threatened with extinction. Data were collected from October 2004 through September 2007 in the state of Rio Grande do Sul. Sampling was conducted randomly from 08:00 a.m. to 6:00 p.m. The capture-mark-recapture method was employed. The lizards were captured by hand, and their cloacal temperature, sex, snout-ventral length (SVL), mass, and the temperature of their microhabitat (substrate temperature and air temperature) were recorded. Individuals were then marked by toe-clipping and released at the site of capture. Body temperatures were obtained for 175 individuals, activity data for 96 individuals, and data on population structure and growth for 59 individuals. All data were obtained monthly, at different times of the day. Cnemidophorus vacariensis average body temperature was 23.84ºC, ranging between 9.6 and 38.2ºC. Temperatures ranged between 21 and 29ºC. The correlation between external heat sources, substrate and air were positive and significant and there was a greater correlation between lizard's temperature and the temperature of the substrate (tigmothermic species). The relatively low body temperatures of individuals are associated with the climate of their environment (altitude up to 1,400 m), with large variations in temperature throughout the day and the year, and low temperatures in winter. The average body temperature observed for C. vacariensis was low when compared with that of phylogenetically related species, suggesting that the thermal biology of this species reflects adaptations to the temperate region where it lives. The monthly rates of activity of lizards were related to monthly variations in the ambient temperatures. Our data suggest that the daily and seasonal activity of C. vacariensis result from the interaction between two factors: changes in the environment temperature and the relationship between individuals and their thermal environment. The population structure of C. vacariensis varied throughout the study period, with maximum biomass in January and maximum density in February (recruitment period). The sex ratio diverged from the expected 1:1. The growth analysis showed a negative relationship between the growth rate of individuals and the SVL, revealing that young individuals grow faster than adults, a typical pattern for short-lived species. The population studied showed a seasonal and cyclical variation associated with the reproductive cycle. The life strategy of C. vacariensis seems to include adaptations to the seasonal variations in temperature, typical of its environment.
topic Temperatura corpórea
crescimento
densidade-biomassa
região temperada
tigmotermia
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212011000300002&lng=en&tlng=en
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