January 1, 2001 to December 31, 2021
These tables give a rough idea of the relative abundance and distribution of Vermont’s herptiles. The comparisons are subject to bias by the audibility, visibility, notoriety, and ease of identification of species. For example, since salamanders don’t 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. Furthermore, 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.
Methodology: We broke the State up into a grid for each species that corresponded to the species’ site size using ArcGIS Pro. Each grid cell was considered to be a potential site. We considered a site to be occupied if an individual was reported within the grid cell.
State Ranks are as of December 2022.
|Species||# of Towns||# of Sites||State Rank||State Status||Site Size||SGCN Priority|
|Eastern Red-backed Salamander||213||702||S5||0.5km|
|Northern Two-lined Salamander||198||451||S5||0.5km|
|Northern Dusky Salamander||180||320||S5||0.5km|
|Blue-spotted Salamander Group||75||234||S4||SC||0.5km||Medium|
|Jefferson Salamander Group||73||165||S2||SC||0.5km||High|
*Nineteen towns and fifty-four sites are in the Lake Champlain basin (native); an additional ten towns and fourteen sites are in the Connecticut River watershed (introduced).
|Species||# of Towns||# of Sites||State Rank||State Status||Site Size||SGCN Status||Last Observation|
|Northern Leopard Frog||68||342||S4||0.5km|
|Boreal Chorus Frog||0||0||S1||E||0.5km||High||1999|
*Also on one NH island in the Connecticut River
Additional Background on the Relative Abundance Tables for Vermont Reptiles and Amphibians
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. Still, the relative rankings within taxonomic groups should be accurate. Numbers of towns and sites for this set of tables were generated by Matt Gorton using Herp Atlas data. Site sizes were generated by Erin Talmage and edited by Jim Andrews.
Both the reptile and amphibian charts summarize data that were gathered by volunteers and professionals using a variety of methods. Records from January 1, 2001 to December 31, 2021 were included. 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. For all 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. Over time, as additional data are gathered, these site sizes may need to be adjusted.