Sable Island Horse Project

Sable Island is a 49 km-long, crescent-shaped sand bar located 160 km off the east coast of Nova Scotia, Canada. Renowned for its windswept and grass-covered dunes, wild horses, and shipwrecks, Sable Island is as unique in character as it is in biological diversity. More than 320 species of birds have been observed on Sable Island, including breeding populations of endangered Roseate Terns and the ‘Ipswich’ subspecies of the Savannah Sparrow, which nests exclusively on Sable. Sable is also home to a number of species of seals, including the world’s largest population of grey seals. The island’s most iconic species—the wild (feral) horse—was introduced in the mid-1700s. The Sable Island horse is of exceptional cultural value to the people of Nova Scotia and is noted as a breed of significant conservation interest due to its distinct genetic heritage. Human presence on the island is restricted to a handful of researchers and visiting scientists, tourists, and managers of the island’s meteorological station. On December 1, 2013, Sable Island came under management of Parks Canada Agency as Sable Island National Park Reserve, and we very much look forward to working with Parks to further our joint interests in ecology and applied conservation biology. Sable Island is truly one of the most interesting outdoor laboratories a population ecologist could ask for! We have a number of projects on the go on Sable Island.

Feral Horses

I have been interested in the ecology and evolution of the Sable Island horse since 2007, when I first set foot on the island (with annual field trips every year since then). Having freshly returned from working on a long-term, individual-based project on red deer of the Isle of Rum in Scotland, I thought it would be neat to start something similar here in Canada. In particular, I set out to establish a program aimed at filling a specific niche in ecology in Canada: the individual-based study of a wild vertebrate that lives free from predation, interspecific competition, and human interference (to allow me to focus on the role of intraspecific density-dependent phenomena in ecology and evolution). After scouting several locations across Canada, I quickly realized that the horses of Sable Island presented an almost ideal system for the study of population ecology and evolution. The horses are the island’s only terrestrial mammal, and have been feral now for more than 30 generations. Sample sizes are large (n = 559 horses in 2013, now number just over 500 horses as at 2018) and each horse is recognizable from photographs; the lack of trees on the island makes it easy to relocate each animal several times a season. The study also provides some new perspectives on the evolution of wild ungulates: e.g., feral horses exhibit a social structure that is very different from other polygynous ungulates, being more similar to that of primates. Also advantageous for the project is that we already know so much about horses—their natural history, behaviour, and even a genome sequence—so we begin our study with a  head start compared to programs on little studied, non-model organisms. For example, linking evolutionary change with molecular genetic variation in natural populations is one of the fundamental but largely inaccessible goals of evolutionary biology. For the Sable Island horses, however, this is not an unrealistic feat.

Since 2007, each summer my collaborators, students, and I have been naming and keeping track of the life histories and movements of every horse that lives on Sable Island, as well as a number of other parameters. We have high hopes for this long-term project to make some significant in-roads into our understanding of how individual dynamics can help us to understand population-level phenomena. We now have a fantastic and continually growing data set, as our study is entering its 12th year of whole-island data collection in summer 2019. Data available for new student projects includes specifics of individual contributions to population growth (survival and reproduction), movement and dispersal patterns, individual exposure to local population density and sex ratios, condition, personality traits such as flight initiation distance, body size for all individuals and ages (from parallel-laser calipers), colouration patterns, parasitology, and for many individuals biological samples for DNA, cortisol, and diet. Our program on island ecology also includes significant work on sea-to-land nutrient transfers and links between seals, seabirds, and horses through vegetation. We maintain a program on the successional dynamics of the island and the role of the horse in this system.

A Collaborative Effort

The Sable Island project is a truly collaborative research program with many contributors, especially my co-PI on the Sable Island project, ecological evolutionary geneticist Dr. Jocelyn Poissant. Jocelyn is an Assistant Professor at the University of Calgary, Department of Veterinary Medicine. We also have several current collaborators at the University of Saskatchewan campus (e.g., Dr. David Janz, Dr. Keith Hobson [Environment Canada, also Western], Dr. Emily Jenkins, and Dr. Todd Shury [who also holds a post with Parks Canada Agency, Office of the Chief Ecosystem Scientist]). Additional collaborators are with the Faculty of Veterinary Medicine, University of Calgary (Dr. John Gilleard). We have a strong and active collaboration with the University of Exeter (Dr. Alastair Wilson), including opportunities for M.Sc. projects through Exeter on horse ecology and quantitative genetics. We also collaborate with several members of Parks Canada Agency for our work on the island.

For a summary of our program, please visit the Sable Island Horse Project on Facebook, where you will also find updates on students’ projects. 

Or check out the Sable Island Horse feed on Twitter, with fast-moving updates and announcements of newly published papers.