66 research outputs found
THE ECOLOGICAL CONSEQUENCES OF HABITAT AND MICROHABITAT USE IN LIZARDS:: A REVIEW
We review the ecological consequences of habitat and microhabitat use in lizards. Different habitats have different biotic and abiotic properties and thus are likely to have different consequences for the lizards that occur in them. Individual performance and life histories are influenced by habitat use, particularly when habitats differ in thermal characteristics that may influence physiological processes or constrain activity. We know relatively little about how the effects of habitat use on individual performance translate into population dynamics. We do know that the ability of lizards to use particular habitats can influence the persistence of populations in the face of habitat changes. Community-level processes (e.g., competition) and community structure (e.g., diversity) can be influenced by habitat use in lizards, often by habitat use facilitating co-existence of two or more potentially competing species. We know relatively little about how other community processes, such as predation and parasitism, are influenced by habitat use
Review of \u3ci\u3eSaving the Prairies: The Life Cycle of the Founding School of American Plant Ecology, 1895-1955\u3c/i\u3e By Ronald C. Tobey
Saving the Prairies is an analysis of the growth, development, and decline of a major school of ecologists centered mostly at the University of Nebraska from the 1890s to the early 1950s. The title stems from Ronald Tobey\u27s conclusion that the demise of the grassland ecologists resulted in part from their involvement in practical problems of range management during and following the devastation of the prairies by the great drought of the 1930s.
The book centers on the ideas, principally plant community succession, developed by Frederic Clements, colleagues such as Roscoe Pound, and a network of students whose research concerned the nature and dynamics of the central grasslands of the United States. Tobey traces the intellectual history of the group from its inception under Charles Bessey through its advancements in quantitative ecology (quadrat analysis) and in theoretical ecology (phytogeography and succession) and eventually to its decline. Within this general chronology Tobey describes the origin of the ideas developed by the Nebraska ecologists in relation to European and American traditions of the time, as well as excellent detail of the activities of the scientists involved, including their travels, correspondence, and conflicts. Tobey\u27s command of the specialized jargon of the science is impressive. He demonstrates how closely the early history and development of ecology as a discipline conforms to general models proposed by Thomas Kuhn and Diana Crane. This appears to be Tobey\u27s principal contribution and goal. Ecologists who deal with the conflicting demands of applied and pure approaches to their science would do well to study the implications of this case history for their own research efforts.
As an ecologist, I hesitate to evaluate this historian\u27s methodology, but I wonder if some of the shortcomings of the book may stem from the choice of materials that Tobey studied. For example, an entire chapter is devoted to criticism of Clementian ideas by the British ecologist A. G. Tansley, whereas the wellknown conflict between Clements and H. A. Gleason is mentioned only peripherally. Similarly, it is incorrect to conclude that basic ecological work on the grasslands disappeared because the founding school scientists became completely involved with applied problems of the drought period. The second generation of Nebraska ecologists were indeed involved with ecological effects of the great drought, but as much for basic descriptive and empirical analyses of this natural experiment as for applied purposes. The extensive archival material of Clements\u27s correspondence with federal agencies perhaps biased Tobey\u27s analysis. There is little in J. E. Weaver\u27s bibliography to suggest that he, the second-generation leader, was capable of providing the theoretical shot in the arm that the group needed. The second generation of scientists were not so much unwilling to abandon their paradigm as they were incapable of creating a new one.
Tobey\u27s account of the grassland ecologists implies that the ideas of succession advanced by Clements died long ago. In fact, however, they linger in a highly modified form in textbooks and symposia. As an example of the latter, the discussion at a 1977 conference of ecologists on succession revealed that, even though the jargon has changed, the ideas on one side of the debate remained essentially Clementian.
Despite these criticisms, Saving the Prairies is a fascinating book. It should be read by ecologists and historians alike
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Xenosaurus grandis
Number of Pages: 4Integrative BiologyGeological Science
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Xenosaurus platyceps
Number of Pages: 2Integrative BiologyGeological Science
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Xenosaurus newmanorum
Number of Pages: 2Integrative BiologyGeological Science
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Xenosaurus
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Distribution and Natural History of Amphibians and Reptiles in Western Nebraska with Ecological Notes on the Herpetiles of Arapaho Prairie
Introduction: The distribution and natural history of amphibians and reptiles have been little studied in the northern states of the great plains. Relative to other vertebrate groups, the herpetofauna of grasslands is depauperate particularly at higher latitudes where temperature becomes a limiting factor to poikilotherms. Nevertheless, certain species of amphibians and reptiles are common in specific habitats and thus form a conspicuous component of the prairie fauna. The purposes of the present study were to document the distributions of herpetiles in a specified region of western Nebraska and to describe general aspects of their natural history. We hope such information will stimulate additiona} work as well as provide a baseline reference for future studies on the herpetofauna of the northern great plains. Previous work on herpetiles in western Nebraska are either in need of updating (e.g. Hudson, 1942) or are anecdotal or not comprehensive (Heyl and Smith, 1957; Gehlbach and Collette, 1959; Iverson, 1975; Lynch, 1978).
Summary: The herpetofauna of the seven county study area in western Nebraska may be characterized in general by a preponderance of organisms exhibiting both wide geographical and wide ecological distributions and tolerances. Species exhibiting little microhabitat specificity and which are found widely throughout the region include the tiger salamander, spadefoot toad, rocky mountain toad, striped chorus frog, lesser earless lizard, fence lizard, racerunner, common racer, bullsnake, red-sided garter snake, plains garter snake, snapping turtle and painted turtle. Those ecologically restricted species that enter the area include the plains leopard frog, common water snake, black-headed snake, yellow mud turtle, Blanding\u27s turtle, and spiny soft-shelled turtle
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Xenosaurus rectocollaris
Number of Pages: 1Integrative BiologyGeological Science
Review of Reptiles and Amphibians of the Cimarron National Grasslands Morton by Joseph T. Collins and Suzanne L. Collins
This small book (pamphlet) provides information about the amphibians and reptiles for the general reader or casual visitor to the Cimarron National Grasslands in southwestern Kansas. Some of the information derives from a brief field trip by the authors in 1987 or from museum specimens and technical literature, but most of the information is not new. Much of the material (some verbatim) comes from J. T. Collins\u27 previous semipopular books on Kansas herpetiles. After a short introduction and a brief discussion of the history of herp collections in the county there is a checklist of the 31 species, a note about threatened and endangered species in Kansas, and comments on how to observe amphibians and reptiles. The remainder of the booklet consists of accounts of species that provide details of identification, size, distribution, and an assortment of natural history information ranging from food to breeding to predators. There are excellent color photographs (seven of these can be found in black and white in Collins\u27 previous book) of all the species as well as selected major habitats of the Cimarron Grasslands. The style is readable and although no glossary of terms is provided, a minimum of technical terms is used without definitions (e.g., cloaca and spermatophore). Most accounts have comments that reinforce the importance of amphibians and reptiles as a component of the environment which blend well with the overall theme of environmental awareness. The section on how the species accounts are organized... would be better placed immediately before the accounts rather than being interrupted by other sections. The lay reader may be puzzled about why some technical names in the checklist consist of three names and others are binomial but the authors are careful to use the appropriate common name that is applicable to either the binomial or trinomial scientific name
Path to Extinction: Impact of Vegetational Change on Lizard Populations on Arapaho Prairie in the Nebraska Sandhills
Since removal of cattle from Arapaho Prairie in 1977, secondary succession has resulted in increased vegetation cover. Studies of resident lizards on a 150 × 150 meter grid revealed: (1) one lizard species (Holbrookia maculata) has essentially been eliminated in 15 years (from a maximum of 74 residents in 1979 to three residents in 1993); (2) a second lizard population (Sceloporus undulatus) has declined from 56 residents in 1979 to fewer than 30 residents in 1993; and (3) preferred microhabitats occupied by lizards have not changed, but their microgeographic distributions have shifted to areas of blowouts, and home ranges have decreased
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