Checklist and status of the amphibians and reptiles of Essex County, Ontario: a 35 year update

Résumé

Essex County, Ontario, supports a diverse assemblage of Canadian herpetofauna. It is home to the only Canadian populations of three species/subspecies and contains two of Canada’s 11 Important Amphibian and Reptile Areas. A checklist and status assessment of the herpetofauna of Essex County was previously compiled in 1983. Changes to natural habitats and an increase in monitoring efforts (e.g., citizen science) over the past 35 years warrant an updated assessment of herpetofaunal status. The county was subdivided using a 10 x 10 km grid overlay, and recent observations (1997–2016) submitted to provincial databases were tabulated for each grid square. We compared current status’ of herpetofauna in Essex County to those of the 1983 study using a similar classification scheme of ‘extirpated from Essex’ (EE; no recent observations) and ‘rare in Essex’ (RE; distribution ≤5 squares). We found that 11 species declined in status. The majority of reptiles and amphibians (62%) that historically occurred in Essex County are now either EE (31%) or RE (31%) and almost half (45%) of the 29 extant species/subspecies are RE. A large proportion of salamanders and squamates are EE or RE (86% and 65%, respectively). Amount of natural area and sampling effort were important variables describing patterns of observed herpetofaunal species/subspecies richness, and observed richness was highest along the western and southern edges of the mainland (16–19 species). To prevent future extirpations, recovery efforts in Essex County should occur across multiple locations and target RE species.