New study on Sable Island looks at role of wild horses in ecosystem

A new study on Sable Island will look at the impact wild horses have on the ecosystem and how they coexist with other flora and fauna. 

"It's an incredible landscape and the horses have been here for hundreds of years and they're well adapted to the environment," said Dan Kehler, an ecologist with Parks Canada who is working on the island.

"What we don't know, though, is their relationships with some of the other really interesting species here on Sable Island."

Parks Canada started the Fences in the Sand project last fall. Officials put up temporary electric fences around nine small areas of the Sable Island National Park Reserve to keep the horses out.

This will allow scientists to measure and compare ecological attributes from inside and outside the exclosures over a five-year period.

Parks Canada says there are 569 wild horses on Sable Island.

"We know the horses have an influence on the island. You can just see it as you're walking around the horse paths, piles of horse poop. If you look at it from the air, you can see quite the network of horse trails," Kehler said.

"At the same time, we know that they are spreading nutrients around, which may be benefiting some species, and there's always a complex interplay when it comes to ecology."

To dissect that complex interplay, scientists will study how the horses affect the ecological integrity of freshwater plants and invertebrates, how they affect rare species and their habitats, and how they impact dune processes like erosion.

For example, scientists know the horses likely have some impact on how dunes are formed because of their grazing patterns.

The less vegetation there is, the more the sand dunes become destabilized and move.

"We've seen, even though there's grass everywhere, some preferential grazing in certain key areas, so dune edges. We're not sure if the grass is more succulent there, but it does have an influence on the way that dune is eroding or grading, so increasing in size," Kehler said.

He said the federal government is spending $776,000 on the project, which will run until 2026.

"We're really excited to see what we can tell just by looking inside and outside, can we see any visual changes?" he said.

"Then a team of researchers will be here to study plants and insects and water quality, both inside and outside the exclosures, and that will give us a sense, probably within two or three years or five years, what sort of role the horse is playing in the ecosystem."

Kehler said he thinks this study will be of interest to Nova Scotians.

"The horses of Sable Island are iconic and people have a really strong attachment to them, but they also care about the island itself," he said.

"So the interplay between the horses and people, I think will be of great interest to better understand the influence that the horses have on the greater ecosystem."