Relative Abundance of Vermont’s Amphibians

January 1, 1987 to December 31, 2011

Jim Andrews, Elizabeth Volpe, & Erin Talmage
12/28/12

These tables give a rough idea of the relative abundance and distribution of Vermontís herptiles. The comparisons are subject to bias by the audibility, visibility, notoriety, and ease of identification of species. For example, since salamanders donít call and are usually under cover, they are reported less often than frogs. Consequently, the species are sorted by taxonomic group so that some of these biases are alleviated. However, some other biases remain. For instance, Eastern Ribbonsnakes when observed may be assumed to be Common Gartersnakes and hence they may be under-reported. Aquatic species of turtle that bask only infrequently are probably reported less often than terrestrial or basking species.

Still, these tables help the Scientific Advisory Group decide if the state rank and/or state status of a species needs to be reevaluated. Species are listed in descending order of the number of “sites” from which they have been reported. Errors in the number of known sites and towns for the more abundant species are almost certainly included and those numbers are changing monthly. There are a total of 255 “towns” (political units including towns, cities, gores, and unincorporated areas) in the state of Vermont.

State Ranks are as of December 2013.

Vermont Amphibian Records

January 1, 1987 to December 31, 2011

Salamanders

Species # of Towns # of Sites State Rank State Status Site Size SGCN Priority
Eastern Newt 221 1151 S5   0.5km  
Spotted Salamander 218 861 S5   0.5km Medium
Eastern Red-backed Salamander 239 777 S5   0.5km  
Northern Two-lined Salamander 216 557 S5   0.5km  
Northern Dusky Salamander 191 413 S5   0.5km  
Spring Salamander 102 181 S4   0.5km  
Blue-spotted Salamander Group 57 175 S3 SC 0.5km Medium
Jefferson Salamander Group 54 94 S2 SC 0.5km High
Mudpuppy 26 38 S2 SC 0.5km High
Four-toed Salamander 21 26 S2 SC 0.5km Medium

Frogs

Species # of Towns # of Sites State Rank State Status Site Size SGCN Status Methods
Green Frog 253 1373 S5 0.5km
Wood Frog 257 1170 S5 0.5km
Spring Peeper 234 1042 S5 0.5km
American Toad 250 1002 S5 0.5km
Gray Treefrog 163 519 S5 0.5km
Pickerel Frog 175 456 S5 0.5km
American Bullfrog 170 423 S5 0.5km
Northern Leopard Frog 74 357 S4 0.5km
Mink Frog 43 75 S3 0.5km
Fowler's Toad 2 2 S1 SC 0.5km High Missing since 2007
Boreal Chorus Frog 1 1 S1 E 0.5km High Missing since 1999

Methods used for Relative Abundance Tables for Vermont Reptiles and Amphibians

(January 1, 1987 to December 31, 2011)

These tables are intended to give the reader an idea of the relative abundance and distribution of Vermont herptiles based on the data in the Vermont Reptile and Amphibian Database. The more common the species, the less accurate the data presented. Exact locations of some reports are difficult to pin down and the large number of reports of more common species makes it certain that some mistakes are included, particularly in the number of sites per species for S4 and S5 species. Detailed location maps have only been generated for a handful of the rarest species. Still, the relative rankings within taxonomic groups should be accurate. Numbers of towns and sites for this set of tables were generated by volunteer Elizabeth Volpe and edited by Jim Andrews. Site sizes were generated by Erin Talmage and also edited by Jim Andrews.

Both the reptile and amphibian charts summarize data that were gathered by volunteers and professionals using a variety of methods. Historical records (before January 1, 1987) were not included, nor were records entered after December 31, 2011. All reports that had been assigned an unverified status in the Vermont Reptile and Amphibian Database were omitted and have not been included in these charts. For rare and often misidentified species, records without vouchers (photos, shed skins, specimens) that came from disjunct locations were not included. In addition, records that were assumed to be released pets were not included. However, for common species in appropriate habitat we did include records that were well described but not accompanied by a voucher photo or specimen. Salamanders identified as Jefferson X Blue-spotted Complex were omitted since they could not be placed in any one species or group.

The size of a “site” varies with the species. Since many herptiles have one or more central habitat features that are required for the persistence of a population (dens and hibernacula, breeding sites, foraging sites, drought refugia, ponds, streams) we estimated a maximum traveling distance based on the literature and unpublished local research. We then doubled this distance assuming that individual organisms might travel in opposite directions from any one feature. Two records further apart than this distance were counted as separate sites. For convenience we lumped all amphibians and the most common (S5) small snakes. For them we defined a site as a location that is equal to or greater than one-half kilometer from the nearest reported location. If two or more records were gathered within a half-kilometer of each other, they were considered to be the same site. For all other species, we used a site-size we felt was appropriate for the species based on its natural history as observed in the field and reported in the literature (see details below). Over time, as additional data are gathered, these site sizes may need to be adjusted.

Citations

Ernst, C.H. and E.M. Ernst. 2005. Snakes of the United States and Canada. Washington: Smithsonian Books.

Ernst, C.H. and J.E. Lovich. 2009. Turtles of the United States and Canada, Second Edition. Johns Hopkins University Press.

Ernst, C.H, J.E. Lovich, and R.W. Barbour.1994. Turtles of the United States and Canada. Washington: Smithsonian Books.

Fitch, H.S. 1999. A Kansas snake community: Composition and changes over 50 years. Malabar, Florida: Krieger Publishing Co.

Gregory, P.T. and K. W. Stewart. 1975. Long distance dispersal and feeding strategy of the Red- sided Gartersnake (Thamnophis sirtalis parietalis) in the Interlake of Manitoba. Canadian Journal of Zoology 53:238-245.

Rowe, J.W. 2003. Activity and Movements of Midland Painted Turtles (Chrysemys picta marginata) Living in a Small Marsh System on Beaver Island, Michigan. Journal of Herpetology 37 (2) 342-353.

Stickel, L.F., W.H. Stickel, and F.C. Schmid. 1980. Ecology of a Maryland population of black rat snakes (Elaphe o. obsolete). American Midland Naturalist 103:1-14.