Literaturdatenbank
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Walton, J. L. (2012). The effects of land mine reclamation on herpetofaunal communities. Unpublished thesis , University of Texas, Arlington.
Added by: Sarina Wunderlich (18 Nov 2012 17:47:11 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Walton2012 View all bibliographic details  |
Categories: General Keywords: Amphibien = amphibians, Chelydra, Chelydra serpentina, Chelydridae, Emydidae, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises, Trachemys, Trachemys scripta Creators: Walton Publisher: University of Texas (Arlington) |
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| Abstract |
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Trachemys scripta Chelydra serpentina Succession describes the process of community change over time after a disturbance. Understanding these processes allows ecological restoration projects to take advantage of natural community trajectories. Reclamation efforts often “jump-start” succession to restore anthropogenically disturbed land and water features to their former state. This is often accomplished by seeding for desired species or planting tree seedlings. One way of gauging whether reclamation was successful is to compare floral and faunal communities of reclaimed land with that of nearby land that was not disturbed. Most such studies have focused on plant and bird species while few have looked at the effects of reclamation on herpetofauna. Reptiles and amphibians are ectothermic, have relatively small home ranges, and are limited in their dispersal abilities. These characteristics might make them more strongly affected by environmental disturbances compared to most birds and mammals. I studied the effects of past strip mining activity and time since reclamation on frog and turtle communities in north-central Texas. I compared the communities inhabiting ponds that had been reclaimed following strip mining to nearby reference ponds that have never been mined. From July 2010-October 2011, I monitored turtle and frog populations, as well as environmental variables such as shoreline vegetation, aquatic vegetation, and turbidity at each pond. While there were no significant differences in turtle and frog species richness, frog species composition was different between mined and unmined ponds. Unmined ponds had smaller turtles than mined ponds, and more species of turtles. I found few differences in the environment of these pond groups when the variables were analyzed independently, though unmined ponds had more trees along the shoreline. Mined and unmined pond environments differed when I used a principle components analysis to analyze these variables together. There were no significant differences in turtle and frog species richness between 20-year and 30-year-old ponds, but species composition was different. Larger turtles were found at ponds that were 30 years post-reclamation. I found no environmental differences between the two pond age groups. Several environmental variables independent of mining or time since reclamation were correlated with characteristics of turtle and frog communities. Aquatic vegetation cover did not differ consistently among pond groups, but it was positively correlated with overall frog species richness as well as hylid richness. In addition, the distance from a pond to a larger water source was unrelated to time since reclamation and mining history, but was correlated with both turtle density and bufonid richness. Past studies in this area found riverine turtle species that were not found in my study. These species were probably unable to establish populations in a pond habitat. These studies also found several species of frogs, known to be explosive breeders, which were not found in my study. I most likely did not detect these species due to their fossorial nature and lack of rain during my field seasons. This study suggests that ponds reclaimed after lignite coal mining are capable of supporting similar species richness’ for turtles and frogs, but have different species compositions compared to unmined ponds. The similarity of turtle and frog species richness and composition between 20 and 30 year old ponds shows that these groups are capable of repatriating an area in less than 20 years, though establishment of mature turtle communities may take longer. Finally, turtles and frogs are probably more influenced by habitat characteristics and land management, such as stocking ponds with fish or protecting stands of trees, than factors directly associated with mine reclamation or time since reclamation.
Added by: Sarina Wunderlich |