What a satellite high above the Earth tells researchers about the St. Marys River

A satelliteorbiting high above the Earthis giving researchers valuable insight into the healthof a Nova Scotia river that acts as a vital habitat for endangered species and isbeloved by paddlers, anglers and birders alike.

The images captured by the European Space Agency's Sentinel-2 mission are at the heart of a new Canadianstudy showing where conservation efforts for the St. Marys River and its lush embankment have been successful.

It's the first time researchers with theDepartment of Fisheries and Oceans have used the satellite to study the St. Marys River.The satellitecan provideimages so detailed they can helpdetermine whether environmental changes are natural or caused by humans.

"We used any higher quality image that would better capture small-scale changes than other satellites used at a national level," saidCaelinMurray,an aquatic biologist with DFOand the study's lead researcher.

Most of watershed undisturbed

The study found the St. Marys River watershed area is "relatively undisturbed," with 75 per cent unaffected by human activities or natural disasters. Of the remaining 25 per cent of land, which hasbeen disturbed largelybyhistorical clear cutting and agricultural practices, very littleis regenerating.

Researchers were particularly focused on the strip of land that runs along the river's edgeknown as ariparian zone because of its importance to land and aquatic species, said Aimee Gromack, a senior biologist at DFO and a member of the research team.

Theteam keptan eye out for adecrease in vegetation,among other factors that could negatively impact the environment.

The study found 19 per cent of the riparian zone wasdisturbed, with nine per cent of that habitatshowing signs of regeneration.

Gromack said the vegetation in this zone provides shading, filters the water from run-off chemicals, and serves as a shelter for other species, so any disturbance could affect the entire ecosystem.

Nearby trees that provide shade and keep the river water cool, for example,are important for the survival of endangered Atlantic salmon, which are very susceptible to warmer temperatures.

Sharper satellite images

Murray saidthe team chosethe St. Marys River for the study because it has "very little human impact" in comparison to other watersheds,soresearcherscould better understand what conservation methods have worked in the area, including initiativesby local organizations and land trusts.

The Sentinel-2 mission was the best optionfor the work becauseit offers images two times clearer than NASA's Landsat 9 satellite. Additionally, the European satellite provides more up-to-date data because itrevisits the same site every five days, considerably shorter than the Landsat 9's 16-day interval, said Murray.

Jaimee Morozoff, director of conservation with the Nova Scotia Nature Trust, said the DFO study will help the organization evaluate its conservation strategies. The trust has already protected approximately 902 hectares of land on the St. Marys River.

"We're [a] science-based organization. We want to make the best decisions for biodiversityusing the most up-to-date information," said Morozoff."This is a great tool to help us inform some of the decision-making."

Morozoff said shehopes the study will promotesimilar research in areas that are not as well preserved as the St. Marys River.

Gromackagreed, saying this kind ofresearch could guide protection effortsbeyond the St. Marys Riverfor years to come.

"This analysis could be done with other watersheds to sort of better determine where there's any opportunities for conservation to look more closely at those areas and think about options," said Gromack.