Growth of Lizards in Natural Populations Exposed to Gamma Irradiation

Turner, Frederick; Hoddenbach, Gerard A.; Lannom, Joseph R.

doi:10.1097/00004032-196512000-00036

Cited by 10 publications

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“…Population density and egg production Body size and density .-Tumer et al (1965) discussed growth and body size of Uta stansburiana in four 9-ha areas in Rock Valley. In 1964-1965 hatchling Uta in Plot 2 were significantly smaller than those in the other three plots. Plot 2 also supported a higher density of Uta than any of the other three areas.…”

Section: Winter Rainfall and Egg Productionmentioning

confidence: 73%

A Population Model of the Lizard Uta stansburiana in Southern Nevada

Turner¹,

Medica²,

Bridges³

et al. 1982

Ecological Monographs

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecological Monographs.Abstract. Population densities, reproduction, and survival of the lizard Uta stansburiana were measured at the Nevada Test Site in southern Nevada, USA, between 1964 and 1974. These data were used to develop a model of the population dynamics of this species. Results of irrigation experiments in 0.4-ha enclosures near Mercury, Nevada, were used to formulate multiple-regression equations predicting frequency and size of clutches laid by two age-classes of females in terms of winter rainfall, March air temperatures, and Uta population density. Densities of Uta in these enclosures were manipulated, and age-specific survival modeled in terms of spring densities of Uta. Experiments in which an important predator on Uta (the leopard lizard, Crotaphytus wislizeni) was removed from enclosures were used to estimate the influence of the predator on basic survival rates of hatchling and older Uta. The model was generally developed from data acquired in the small enclosures, but predictions were compared with actual observations of changes in Uta populations in Rock Valley (19 km west of Mercury, Nevada) between 1966 and 1972.Agreement between model predictions and actual numbers was fair. The model predicted a decrease in density from 1966 to 1967, but numbers of Uta actually increased conspicuously at this time. This was the only major discrepancy between predictions and observations. The observed mean spring density (d) between 1967 and 1972 was 41.4 Uta/ha (SD = 20.8), while the model predicted a mean density of 37.8 Uta/ha (SD = 13.6). Observed and predicted mean proportions of yearlings in spring populations were identical (0.78).The basic version of the model estimated different survival rates for two age-groups of adult Uta. A simpler version of the model, using a common survival rate for both age-groups, gave predictions essentially identical with those of the basic model. Other tests of the basic model showed it to be most sensitive to changes in winter rainfall and predation pressure, much less so to air temperatures. Fifteenand 30-yr synthetic sequences of predator densities were used to examine model stability over longer periods of time. When predator densities were drawn randomly from distributions with a mean of 2 individuals/ha, model populations exhibited lower mean numbers and amplitudes than actually observed during 9 yr in Rock Valley.The basic model included three density-dependent parameters: clutch frequency, clutch size, and adult survival. The model was modified so that (1) egg production was density independent, while adult survival was not; (2...

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Section: Winter Rainfall and Egg Productionmentioning

confidence: 73%

A Population Model of the Lizard Uta stansburiana in Southern Nevada

Turner¹,

Medica²,

Bridges³

et al. 1982

Ecological Monographs

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“…Differences in average length and weight of lizards among plots observed the first year of irradiation were not attributed to ionizing radiation (Turner, Hoddenbach, and Lannom, 1965). One of the most comprehensive studies of effects of low level irradiation on a wild mammal population was that supervised by N. R. French at the Nevada Test Site.…”

Section: Irradiated Ecosystemsmentioning

confidence: 99%

Radiation ecology

Schultz

Whicker

Klement³

1974

C R C Critical Reviews in Environmental Control

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“…The effects of long-term exposure of a natural desert community to low levels of chronic gamma radiation are being studied in a 20-acre enclosure at the Nevada Test Site (French 1964, Turner, Hoddenbach and Lannom, Jr. 1965, French, Maza and Aschwanden 1966. One purpose of this research is to determine the actual radiation doses sustained by animals, as distinguished from the free-air doses registered by continuously exposed static dosimeters.…”

Section: Introductionmentioning

confidence: 99%

Radiation Doses Sustained by Lizards in a Continuously Irradiated Natural Enclosure

Turner¹,

Lannom²

1968

Ecology

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Desert lizards occupying a 20—acre experimental facility continuously exposed to gamma radiation sustain tissue doses which are less than the cumulative free—air dose. Vegetation and terrain afford some shielding, but time spent below ground is the major source of protection. We estimate that, in the course of a year, tissue doses sustained by Uta stansburiana are from 0.3 to 0.6 of the cumulative free—air dose, and that about 1/3 of the total dose is experienced between June and August. Cnemidophorus tigris spends less time above ground, and sustains annual doses representing only about 0.1 to 0.2 of total incident gamma radiation. The dose experience of Crotaphytus wislizeni is intermediate to the other two species. Dose regimes experienced by Uta stansburiana in the experimental area are not acutely lethal.

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Growth of Lizards in Natural Populations Exposed to Gamma Irradiation

Cited by 10 publications

References 0 publications

A Population Model of the Lizard Uta stansburiana in Southern Nevada

A Population Model of the Lizard Uta stansburiana in Southern Nevada

Radiation ecology

Radiation Doses Sustained by Lizards in a Continuously Irradiated Natural Enclosure

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