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Articles 1 - 7 of 7
Full-Text Articles in Ecology and Evolutionary Biology
The Global Decline Of Reptiles, Deja’ Vu Amphibians, J. Whitfield Gibbons, David E. Scott, Travis J. Ryan, Kurt A. Buhlmann, Tracey D. Tiuberville, Brian S. Metts, Judith L. Greene, Tony Mills, Yale Leiden, Sean Poppy, Christopher T. Winne
The Global Decline Of Reptiles, Deja’ Vu Amphibians, J. Whitfield Gibbons, David E. Scott, Travis J. Ryan, Kurt A. Buhlmann, Tracey D. Tiuberville, Brian S. Metts, Judith L. Greene, Tony Mills, Yale Leiden, Sean Poppy, Christopher T. Winne
Travis J. Ryan
Reptile species are declining on a global scale. Six significant threats to reptile populations are habitat loss and degradation, introduced invasive species, environmental pollution, disease, unsustainable use, and global climate change.
Effects Of Hydroperiod On Metamorphosis In Rana Sphenocephala, Travis J. Ryan, Christopher T. Winne
Effects Of Hydroperiod On Metamorphosis In Rana Sphenocephala, Travis J. Ryan, Christopher T. Winne
Travis J. Ryan
Hydroperiod, the time a temporary pond holds water, is an important factor influencing recruitment in amphibian populations and structuring amphibian communities. We conducted an experiment to test the effect of hydroperiod on metamorphic traits of the southern leopard frog (Rana sphenocephala), a common amphibian in the southeastern United States. We reared larval R. sphenocephala in artificial ponds at a density of 32 larvae per tank (initial volume = approximately 650 liter). We dried the tanks according to natural patterns, using three different hydroperiods (60, 75 and 90 d). Experimental hydroperiods had a significant effect on the number of metamorphs and …
Sub-Lethal Effects Of 2,4-D Exposure On Golf Course Amphibians, Travis J. Ryan, Catherine M. Scott, Brooke A. Douthitt
Sub-Lethal Effects Of 2,4-D Exposure On Golf Course Amphibians, Travis J. Ryan, Catherine M. Scott, Brooke A. Douthitt
Travis J. Ryan
Amphibians are among the most common vertebrates inhabiting golf courses. They are frequent inhabitants of golf course wetlands, where they are likely to be episodically exposed to small quantities of herbicides in proper golf course maintenance. The goal of this study was to investigate whether amphibian larvae subjected to sublethal concentrations of a common herbicide used in golf course maintenance would likely result in significant life history, locomotor, or behavioral effects (e.g., changes in growth, swimming speed, or feeding ability). For these experiments we selected as models tadpoles of the southern leopard frog (Rana sphenocephala) and the herbicide 2,4- dichlorophenoxyacetic …
Intraspecific Heterochrony And Life History Evolution: Decoupling Somatic And Sexual Development In A Facultatively Paedomorphic Salamander, Travis J. Ryan, Raymond D. Semlitsch
Intraspecific Heterochrony And Life History Evolution: Decoupling Somatic And Sexual Development In A Facultatively Paedomorphic Salamander, Travis J. Ryan, Raymond D. Semlitsch
Travis J. Ryan
Morphological features such as size and shape are the most common focus in studies of heterochronic change. Frequently, these easily observed and measured features are treated as a major target of selection, potentially ignoring traits more closely related to fitness. We question the primacy of morphological data in studies of heterochrony, and instead suggest that principal sources of fitness, such as life history characteristics, are not only the chief targets of selection, but changes in them may necessitate changes in other (subordinate) elements of the organism. We use an experimental approach to investigate the timing of metamorphosis and maturation in …
Trials Of The Urban Ecologist, Rebecca W. Dolan, Tim Carter, Travis J. Ryan, Carmen M. Salsbury, Thomas E. Dolan, Marjorie Hennessy
Trials Of The Urban Ecologist, Rebecca W. Dolan, Tim Carter, Travis J. Ryan, Carmen M. Salsbury, Thomas E. Dolan, Marjorie Hennessy
Travis J. Ryan
A group of scientists describe some of the obstacles encountered and insights gained while carrying out ecological research in and around the city of Indianapolis.
Movement And Habitat Use Of The Snapping Turtle In An Urban Landscape, Travis J. Ryan, William A. Peterman, Jessica D. Stephens, Sean C. Sterrett
Movement And Habitat Use Of The Snapping Turtle In An Urban Landscape, Travis J. Ryan, William A. Peterman, Jessica D. Stephens, Sean C. Sterrett
Travis J. Ryan
In order to effectively manage urban habitats, it is important to incorporate the spatial ecology and habitat use of the species utilizing them. Our previous studies have shown that the distribution of upland habitats surrounding a highly urbanized wetland habitat, the Central Canal (Indianapolis, IN, USA) influences the distribution of map turtles (Graptemys geographica) and red-eared sliders (Trachemys scripta) during both the active season and hibernation. In this study we detail the movements and habitat use of another prominent member of the Central Canal turtle assemblage, the common snapping turtle, Chelydra serpentina. We find the same major upland habitat associations …
Movement And Habitat Use Of Two Aquatic Turtles (Graptemys Geographic And Trachemys Scripta) In An Urban Landscape, Travis J. Ryan, C A. Conner, B A. Douthitt, S C. Sterrett, Carmen M. Salsbury
Movement And Habitat Use Of Two Aquatic Turtles (Graptemys Geographic And Trachemys Scripta) In An Urban Landscape, Travis J. Ryan, C A. Conner, B A. Douthitt, S C. Sterrett, Carmen M. Salsbury
Travis J. Ryan
Our study focuses on the spatial ecology and seasonal habitat use of two aquatic turtles in order to understand the manner in which upland habitat use by humans shapes the aquatic activity, movement, and habitat selection of these species in an urban setting. We used radiotelemetry to follow 15 female Graptemys geographica (common map turtle) and each of ten male and female Trachemys scripta (red-eared slider) living in a man-made canal within a highly urbanized region of Indianapolis, IN, USA. During the active season (between May and September) of 2002, we located 33 of the 35 individuals a total of …