Thermal Ecology of Habitat and Microhabitat Use by Sympatric Varanus bengalensis and V. salvator in Sri Lanka

Copeia ◽  
1993 ◽  
Vol 1993 (3) ◽  
pp. 709 ◽  
Author(s):  
Eric D. Wikramanayake ◽  
Gil L. Dryden
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Kathleen N Ivey ◽  
Margaret Cornwall ◽  
Hayley Crowell ◽  
Nargol Ghazian ◽  
Emmeleia Nix ◽  
...  

Abstract Recognizing how climate change will impact populations can aid in making decisions about approaches for conservation of endangered species. The blunt-nosed leopard lizard (Gambelia sila) is a federally endangered species that, despite protection, remains in extremely arid, hot areas and may be at risk of extirpation due to climate change. We collected data on the field-active body temperatures, preferred body temperatures and upper thermal tolerance of G. sila. We then described available thermal habitat using biophysical models, which allowed us to (i) describe patterns in lizard body temperatures, microhabitat temperatures and lizard microhabitat use; (ii) quantify the lizards’ thermoregulatory accuracy; (iii) calculate the number of hours they are currently thermally restricted in microhabitat use; (iv) project how the number of restricted hours will change in the future as ambient temperatures rise; and (v) assess the importance of giant kangaroo rat burrows and shade-providing shrubs in the current and projected future thermal ecology of G. sila. Lizards maintained fairly consistent daytime body temperatures over the course of the active season, and use of burrows and shrubs increased as the season progressed and ambient temperatures rose. During the hottest part of the year, lizards shuttled among kangaroo rat burrows, shrubs, and open habitat to maintain body temperatures below their upper thermal tolerance, but, occasionally, higher than their preferred body temperature range. Lizards are restricted from staying in the open habitat for 75% of daylight hours and are forced to seek refuge under shrubs or burrows to avoid surpassing their upper thermal threshold. After applying climatic projections of 1 and 2°C increases to 2018 ambient temperatures, G. sila will lose additional hours of activity time that could compound stressors faced by this population, potentially leading to extirpation.


2019 ◽  
Vol 40 (4) ◽  
pp. 487-498
Author(s):  
María de Fuentes-Fernández ◽  
Ma Mercedes Suárez-Rancel ◽  
Miguel Molina-Borja

Abstract Many selective pressures modulate microhabitat choice of ectotherms, such as temperature, humidity and habitat heterogeneity, and these vary in space and time. Here we analysed: 1) microhabitat selection comparing characteristics of stones (and their surroundings) under which geckos (Tarentola delalandii, mainly nocturnal) were found during the day with that of stones selected randomly; 2) relationship of a measure of body size to microhabitat characteristics (stone and herb covers, etc., and temperature/humidity) and cloacal temperature of males, females and juveniles from two contrasting habitats of Tenerife (northern and southern localities) and in two periods of the year (Spring-Summer and Autumn-Winter). In comparison with randomly selected stones, geckos significantly selected stones with lower temperature in the Spring-Summer and microhabitats with high stone cover. Gecko size was significantly larger in the Northern than in the Southern locality, in spring – summer than in autumn – winter and in males than in females. In both populations and time periods, the largest body sizes were significantly associated with higher environmental and shelter temperatures and with low values of humidity and stone cover. Cloacal and shelter temperatures were positively and significantly related; at higher values of the latter, juveniles attained significantly higher temperatures than adult males but lower than that of females. Larger body size was associated with high shrub and leaf litter covers and high values of shelter dimensions. Therefore, we suggest that in relation to their body sizes, geckos seem to select their shelters considering specific microhabitat characteristics surrounding them that may provide thermoregulatory and/or antipredator profits.


2021 ◽  
Vol 109 (2) ◽  
Author(s):  
César A. Díaz-Marín ◽  
Ricardo Luría-Manzano ◽  
Guadalupe Gutiérrez-Mayén ◽  
Aurelio Ramírez-Bautista

2015 ◽  
Vol 21 ◽  
pp. 114-115
Author(s):  
Kavinga Gunawardane ◽  
Noel Somasundaram ◽  
Neil Thalagala ◽  
Pubudu Chulasiri ◽  
Sudath Fernando

Crisis ◽  
2010 ◽  
Vol 31 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Sudath Samaraweera ◽  
Athula Sumathipala ◽  
Sisira Siribaddana ◽  
S. Sivayogan ◽  
Dinesh Bhugra

Background: Suicidal ideation can often lead to suicide attempts and completed suicide. Studies have shown that Sri Lanka has one of the highest rates of suicide in the world but so far no studies have looked at prevalence of suicidal ideation in a general population in Sri Lanka. Aims: We wanted to determine the prevalence of suicidal ideation by randomly selecting six Divisional Secretariats (Dss) out of 17 in one district. This district is known to have higher than national average rates of suicide. Methods: 808 participants were interviewed using Sinhala versions of GHQ-30 and Beck’s Scale for Suicidal Ideation. Of these, 387 (48%) were males, and 421 (52%) were female. Results: On Beck’s Scale for Suicidal Ideation, 29 individuals (4%) had active suicidal ideation and 23 (3%) had passive suicidal ideation. The active suicidal ideators were young, physically ill and had higher levels of helplessness and hopelessness. Conclusions: The prevalence of suicidal ideation in Sri Lanka is lower than reported from the West and yet suicide rates are higher. Further work must explore cultural and religious factors.


Crisis ◽  
2002 ◽  
Vol 23 (3) ◽  
pp. 104-107 ◽  
Author(s):  
Murad M. Khan

Summary: The Indian subcontinent comprises eight countries (India, Pakistan, Bangladesh, Nepal, Sri Lanka, Afghanistan, Bhutan, and the Maldives) and a collective population of more than 1.3 billion people. 10% of the world's suicides (more than 100,000 people) take place in just three of these countries, viz. India, Sri Lanka, and Pakistan. There is very little information on suicides from the other four countries. Some differences from suicides in Western countries include the high use of organophosphate insecticides, larger numbers of married women, fewer elderly subjects, and interpersonal relationship problems and life events as important causative factors. There is need for more and better information regarding suicide in the countries of the Indian subcontinent. In particular, studies must address culture-specific risk factors associated with suicide in these countries. The prevention of this important public health problem in an area of the world with myriad socio-economic problems, meager resources, and stigmatization of mental illness poses a formidable challenge to mental health professionals, policy makers, and governments of these countries.


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