COS 136-5 - Sex-specific differences in familial networks, dispersal and reproductive success are driven by heterogeneity in density

Wednesday, August 17, 2022

9:00 AM – 9:15 AM EDT

Location: 515A

Presenting Author(s)

MM

Micheline Manseau

Landscape Science and Technology Division, Environment and Climate Change Canada, Canada

Co-Author(s)

SM

Samantha McFarlane, PhD

Wildlife Biologist
Canadian Wildlife Service, Environment and Climate Change Canada, Ontario, Canada

Coauthor(s)

TJ

Teri Jones

Environmental and Life Sciences Department, Trent University, Canada
DP

Darren Pouliot

Environment and Climate Change Canada, Canada
GM

Gabriela Mastromonaco

Toronto Zoo, Ontario, Canada
GP

Gigi Pittoello

Saskatchewan Ministry of Environment, 3211 Albert Street, Regina, SK, Canada S4S 5W6., Saskatchewan, Canada
PW

Paul J. Wilson

Environmental and Life Sciences Department, Trent University, Canada

Background/Question/Methods

Density is an important demographic parameter that is commonly overlooked in studies of wild populations. We examined a range of spatially explicit demographic parameters in a wild population of a cryptic ungulate, boreal woodland caribou (Rangifer tarandus caribou). Using noninvasive genetic sampling, we used spatial capture-recapture with covariates to estimate density of boreal woodland caribou across a 108 806 km² study area. We then created a familial network from reconstructed parent-offspring relationships and determined whether spatial density influenced sex-specific dispersal distance, individual reproductive success, and female pregnancy status.

Results/Conclusions

We showed that caribou density varied greatly, leading to variation in dispersal distances, with offspring moving shorter distances when parents were found in higher density areas. This significantly affected both male and female reproductive success, with males showing positive density dependence, and females showing negative density dependence. No differences were found in pregnancy rates of females occurring in high- and low-density areas. Familial network reconstruction using genetic data showed that demographic parameters of both males and females were density-dependent. Although high density areas do reflect good quality caribou habitat, the observed decreased dispersal rates and lower female recruitment rates suggest that remnant habitat patches may trigger positive feedbacks.