Population size and spatial ecology of Blanding’s Turtle (Emydoidea blandingii) in South March Highlands, Ottawa, Ontario, Canada

Abstract

Between 2010 and 2011, an arterial road was constructed within provincially significant wetlands in the South March Highlands (SMH) located in Ottawa, Ontario, Canada. The wetlands and adjacent upland areas were determined to be sensitive habitat for Blanding’s Turtles (Emydoidea blandingii (Holbrook, 1838)) during the approval and permitting process, and a population study was required as part of the road construction project. The study consisted of a 4-year mark–recapture program and a movement study of radio-tagged adult turtles. General findings included the identification of 27 adult males and 55 females and a population estimate of 93 adults (95% Cl: 86–118). A 1:2.32 male to female sex bias was also found. Mean home-range size was 19.06 ha and tagged turtles moved, on average, more per observation in 2013 (191.40 m compared with 89.75 and 123.04 m in 2011 and 2012, respectively). Previously reported differences in movement patterns between males, females, and gravid females were not observed. The SMH Blanding’s Turtle population should be closely monitored because urban development continues in the area, which may further reduce the population size. Understanding the biology of imperiled populations across species’ ranges is necessary to promote conservation and adaptive wildlife management.

Demographic evidence that development is not compatible with sustainability in semi‐urban freshwater turtles

“…The turtle population was previously monitored by the City of Ottawa (2010–2013, Hasler et al ., 2015; Dillon Consulting Limited 2013) and we compare contemporary (2017–2020) site features and turtle demography to those observed by Hasler et al . (2015), allowing our study to span 10 years.…”

“…Between 2011 and 2013, 92 Blanding's turtles were captured, of which 21 were equipped with VHF radio‐transmitters and tracked for survival and location on average every 4 days (Hasler et al ., 2015; Dillon Consulting Limited 2013). During 2017–2020, we captured 36 Blanding's turtles and equipped 31 adults with GPS (AxyTrek, Technosmart, Rome, Italy; GPS accuracy ±17.4 m, A. Auge, unpubl.)…”

“…Following development beginning in 2008, several mitigation measures were established with the intent to protect at-risk turtles, including: ~2 km of wildlife fencing along Terry Fox Drive (2008), construction of 10 road culverts to allow turtle passage from SMH to Kizell Cell Wetland ( 2008) and construction of one artificial turtle nesting area (0.3 ha) and two artificial ponds (2017; total area = 0.5 ha) (Dillon Consulting Limited 2013; DST Consulting Engineers 2015). The turtle population was previously monitored by the City of Ottawa (2010-2013, Hasler et al, 2015Dillon Consulting Limited 2013) and we compare contemporary (2017-2020) site features and turtle demography to those observed by Hasler et al (2015), allowing our study to span 10 years.…”

“…During both study periods, turtles were captured between May and September using baited hoop nets or by hand, assigned age classes (hatchling, juvenile and adult) based on body size and mass (Congdon & van Loben Sels, 1991;Hasler et al, 2015), sexed based on secondary sexual characters (Congdon & van Loben Sels, 1991;Hamernick, 2000) and individually marked with carapace notches (Cagle, 1939). Because the 2010-2013 study included a site to the north of the study area that was not sampled in 2017-2020 (c. 110 ha), we excluded data (n = 9 turtles) from that site.…”

Evaluation of headstarting as a conservation tool to recover Blanding’s Turtles (Emydoidea blandingii) in a highly fragmented urban landscape

“…The sex ratio in the RNUP population was equal, although wild populations often demonstrate a female-biased sex ratio [55,[67][68][69][70]. However, in most studies, the sex ratio reported is likely an artefact of biased sampling and not a true reflection of the population sex ratio.…”