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Weaver SJ, Axsom IJ, Peria L, McIntyre T, Chung J, Telemeco RS, Westphal MF, Taylor EN. Hydric physiology and ecology of a federally endangered desert lizard. CONSERVATION PHYSIOLOGY 2024; 12:coae019. [PMID: 38715929 PMCID: PMC11074591 DOI: 10.1093/conphys/coae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/22/2024] [Accepted: 03/28/2024] [Indexed: 05/24/2024]
Abstract
Animals can respond to extreme climates by behaviourally avoiding it or by physiologically coping with it. We understand behavioural and physiological thermoregulation, but water balance has largely been neglected. Climate change includes both global warming and changes in precipitation regimes, so improving our understanding of organismal water balance is increasingly urgent. We assessed the hydric physiology of US federally endangered blunt-nosed leopard lizards (Gambelia sila) by measuring cutaneous evaporative water loss (CEWL), plasma osmolality and body condition. Measurements were taken throughout their active season, the short period of year when these lizards can be found aboveground. Compared to a more mesic species, G. sila had low CEWL which is potentially desert-adaptive, and high plasma osmolality that could be indicative of dehydration. We hypothesized that throughout the G. sila active season, as their habitat got hotter and drier, G. sila would become more dehydrated and watertight. Instead, CEWL and plasma osmolality showed minimal change for females and non-linear change for males, which we hypothesize is connected to sex-specific reproductive behaviours and changes in food availability. We also measured thermoregulation and microhabitat use, expecting that more dehydrated lizards would have lower body temperature, poorer thermoregulatory accuracy and spend less time aboveground. However, we found no effect of CEWL, plasma osmolality or body condition on these thermal and behavioural metrics. Finally, G. sila spends considerable time belowground in burrows, and burrows may serve not only as essential thermal refugia but also hydric refugia.
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Affiliation(s)
- Savannah J Weaver
- Department of Biological Sciences, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, Fisher Science, 1 Grand Avenue, San Luis Obispo, CA 93407-0401, USA
| | - Ian J Axsom
- Department of Biological Sciences, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, Fisher Science, 1 Grand Avenue, San Luis Obispo, CA 93407-0401, USA
| | - Lindsay Peria
- Department of Biological Sciences, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, Fisher Science, 1 Grand Avenue, San Luis Obispo, CA 93407-0401, USA
| | - Tess McIntyre
- Department of Biological Sciences, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, Fisher Science, 1 Grand Avenue, San Luis Obispo, CA 93407-0401, USA
| | - Justin Chung
- Department of Biological Sciences, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, Fisher Science, 1 Grand Avenue, San Luis Obispo, CA 93407-0401, USA
| | - Rory S Telemeco
- Department of Conservation Science, Fresno Chaffee Zoo, 894 W Belmont Avenue, Fresno, CA 93728, USA
- Department of Biology, College of Science and Mathematics, California State University, Fresno, 2555 East San Ramon Ave, Fresno, CA 93740, USA
| | - Michael F Westphal
- Central Coast Field Office, Bureau of Land Management, 940 2nd Avenue, Marina, CA 93933, USA
| | - Emily N Taylor
- Department of Biological Sciences, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, Fisher Science, 1 Grand Avenue, San Luis Obispo, CA 93407-0401, USA
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Zuliani M, Ghazian N, Owen M, Westphal MF, Butterfield HS, Lortie CJ. Shrub density effects on the presence of an endangered lizard of the Carrizo Plain National Monument, California. Ecol Evol 2023; 13:e10128. [PMID: 37214602 PMCID: PMC10199236 DOI: 10.1002/ece3.10128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/24/2023] Open
Abstract
Positive associations between animals and foundational shrub species are frequent in desert ecosystems for shelter, resources, refuge, and other key ecological processes. Herein, we tested the impact of the density of the shrub species Ephedra californica on the presence and habitat use of the federally endangered lizard species, Gambelia sila. To do this, we used a 3-year radio telemetry dataset and satellite-based counts of shrub density across sites at the Carrizo Plain National Monument in San Luis Obispo County, CA. The effect of shrub density on lizard presence was contrasted with previous shrub cover analyses to determine whether measures of shrub density were superior to shrub cover in predicting lizard presence. Increasing shrub density increased lizard presence. As shrub density increased, lizards were located more frequently "above ground" versus "below ground" in burrows. Male lizards had significantly larger home ranges than females, but both sexes were similarly associated with increasing shrub densities. Shrub density and shrub cover models did not significantly differ in their prediction of lizard presence. These findings suggest that both habitat measures are effective analogs and that ecologically, both cover and the density of foundation shrub species are key factors for some desert lizards.
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Affiliation(s)
- Mario Zuliani
- Department of Biological ScienceYork UniversityTorontoOntarioCanada
| | - Nargol Ghazian
- Department of Biological ScienceYork UniversityTorontoOntarioCanada
| | - Malory Owen
- Department of Biological ScienceYork UniversityTorontoOntarioCanada
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Ivey KN, Cornwall M, Crowell H, Ghazian N, Nix E, Owen M, Zuliani M, Lortie CJ, Westphal M, Taylor E. Thermal ecology of the federally endangered blunt-nosed leopard lizard ( Gambelia sila). CONSERVATION PHYSIOLOGY 2020; 8:coaa014. [PMID: 33649711 PMCID: PMC7047230 DOI: 10.1093/conphys/coaa014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 01/23/2020] [Accepted: 02/02/2020] [Indexed: 05/30/2023]
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.
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Affiliation(s)
- Kathleen N Ivey
- Biological Sciences Department, California Polytechnic State University, 1 Grand Ave. San Luis Obispo, CA 93401-0401, USA
| | - Margaret Cornwall
- Biological Sciences Department, California Polytechnic State University, 1 Grand Ave. San Luis Obispo, CA 93401-0401, USA
| | - Hayley Crowell
- Biological Sciences Department, California Polytechnic State University, 1 Grand Ave. San Luis Obispo, CA 93401-0401, USA
| | - Nargol Ghazian
- Department of Biology, York University, 4700 Keele St. Toronto, Ontario M3J1P3, Canada
| | - Emmeleia Nix
- Central Coast Field Office, US Bureau of Land Management, 940 2nd Ave. Marina, CA 93933, USA
| | - Malory Owen
- Department of Biology, York University, 4700 Keele St. Toronto, Ontario M3J1P3, Canada
| | - Mario Zuliani
- Department of Biology, York University, 4700 Keele St. Toronto, Ontario M3J1P3, Canada
| | - Christopher J Lortie
- Department of Biology, York University, 4700 Keele St. Toronto, Ontario M3J1P3, Canada
| | - Michael Westphal
- Central Coast Field Office, US Bureau of Land Management, 940 2nd Ave. Marina, CA 93933, USA
| | - Emily Taylor
- Biological Sciences Department, California Polytechnic State University, 1 Grand Ave. San Luis Obispo, CA 93401-0401, USA
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