Showing posts with label Thamnophis sirtalis. Show all posts
Showing posts with label Thamnophis sirtalis. Show all posts

Monday, November 7, 2011

The Earthworm, The Salamander, & The Garter Snake

Organisms that alter the physical structure of their environments are ecosystem engineers and they create new habitat that can be exploited by other species in multiple ways, beavers, termites, leaf cutter ants, and mud lobsters are all environmental engineers, as are earthworms that improve the environment for use by other species. Ransom (2011) experimented with earthworms and red-backed salamanders (Plethodon cinereus) in an effort to determine if salamanders use earthworm burrows, and if they do, to examine the influence earthworm burrow use has on the salamander's competition with other salamanders and their ability to survive predators. Ransom found red-back salamander used earthworm burrows 50% of the time when burrows were present. However, the slimy salamander, Plethodon glutinosus, did not use the worm burrows. When other slimy salamanders were present or the red-backed were alone they used cover objects 70% of the time instead of the worm burrows, when other red-backed salamanders were present P. cinereus used cover objects only 40% of the time. The presence of earthworms did not change the behavior of the red-backed salamanders. Earthworms reduced the leaf litter and the number of micro invertebrates but did not impact the mass of salamanders in the study area. Additional experiments suggest that the use of earthworm burrows allowed the red backed salamanders to escape predation from garter snakes (Thamnophis sirtalis) and increased their survival rate during the winter.

Citation
Ransom, T. S. 2011.  The influence of habitat provisioning: use of earthworm burrows by the terrestrial salamander, Plethodon cinereus. Oecologia, 165: 745-754.

Wednesday, September 14, 2011

Buffer Zones For Snakes in Agricultural Landscapes

The Eastern Garter Snake, Thamnophis sirtalis. JCM
Roadside shoulders covered with vegetation, and gallery vegetation growing along streams that run through agricultural fields can act as buffers and corridors for wildlife. These linear strips of habitat are all that remains for hundreds of thousands of square miles that have been turned into the breadbasket for America. Land management agencies in the United States promote conservation buffer strips as beneficial to wildlife populations but little is known about how snake use these habitats, Knoot and Best (2011) evaluated the influence of buffer design, management, and surrounding landscape characteristics on snake occurrence in gallery grasslands along waterways in southeastern Iowa. They documented snakes in about 80% of the areas and captured 119 individuals representing five species (Storeria dekayi, Thamnophis sirtalis, Thamnophis radix, Liochlorophis (=Opheodrys) vernalis, Elaphe (=Pantherophis) vulpina). The Smooth Green Snake (Liochlorophis vernalis), is listed as a species of concern in Iowa. The width of the waterway was the best predictor of snake presence for three of the five species. The Plains Garter Snake was most often in grass-lined waterways farther from wooded habitat; a finding that is consistent with the observation that Plains Garter Snakes are more often found in open habitats; while the Smooth Green Snake was more often associated with waterways with greater plant litter cover but the reverse was the habitat most often assocaited with the Eastern Garter Snake. Most research on buffers in agricultural has focused habitat for birds and butterflies, but this project suggests that snakes can also be managed in these narrow buffer zones of habitat. This paper is available on-line.

Citation
Knoot, T. G. and L. B. Best. 2011. A multiscale approach to understanding snake use of conservation buffer strips in an agricultural landscape. Herpetological Conservation and Biology 6:191-201.