A study from the University of Victoria shows drift logs are damaging intertidal ecosystems in British Columbia, affecting species like barnacles.
A new study by biologists at the University of Victoria shows that the back-and-forth motion of drift logs on B.C. beaches is harming important ecosystems. These ecosystems are vital for ocean health.
Visitors to West Coast beaches often see free-floating drift logs washed ashore. When the tides recede, the logs move out, and when the tides come in, they crash onto rocks and beaches.
“That intertidal zone … between the high tide and the low tide [supports] a tremendous diversity of life,” said Thomas Reimchen, an adjunct professor at the University of Victoria.
Researchers found that the movement of these logs leads to a significant loss of species like barnacles in intertidal areas. Caroline Barghout reported that the lumber industry is shifting away from a log transportation method that some believe contributes to this issue.
The study, published in the Marine Ecology journal, found that there are 20 to 80 percent fewer barnacles on rocks exposed to logs compared to protected areas. Fewer barnacles mean less food for species that depend on them.
“This is a coast-wide phenomenon that we’re losing those foundation species that are so important for so many other species,” said Reimchen.
Chris Harley, a zoology professor at the University of British Columbia, noted that scientists have long recognized drift logs as a problem. “I have often shaken my fist at drift logs which float by and destroy my precious experiments on the shore,” he said.
Harley added that the UVic study effectively examined the extent of the problem. “Drifting logs are a form of disturbance. They knock off mussels, barnacles, and other marine life,” he explained.
While some disturbance can promote diversity, too much can eliminate habitat-forming species, leading to a loss of food for birds, fish, and sea stars.
To conduct the study, Reimchen and two undergraduate students, Esteban Pérez Andresen and Melanie Marchant, used Google Earth’s satellite imagery and archival photos to measure log abundance along the western shores of B.C. and Haida Gwaii.
They found a 520 percent increase in drift logs since the late 19th century, including on remote shores, with over half coming from the logging industry.
A separate study from the B.C. Conservation Foundation, in collaboration with the Cowichan Tribes, found that log booms negatively impact salmon survival in the Cowichan estuary. Log booms are floating structures where logs are tethered together and transported by boats.
“The number of logs we’ve identified with Google Earth continues to accumulate because of these booms, which sometimes break apart during storms,” said Reimchen.
Even in the most remote areas, large concentrations of logs were found everywhere they looked on Google Earth, which Reimchen believes has contributed to the decline of certain species in North America.
The B.C. government stated that the forestry sector is moving towards using barges for log transportation instead of log booms. A provincial spokesperson said this change will likely reduce the number of loose logs.
“While we anticipate numbers to gradually fall over the years from this transportation change, the [province] has regulations to support the collection, or salvage, of loose logs in coastal B.C.,” the spokesperson wrote in an email.
According to the spokesperson, there are 53 active licensed salvagers who play a key role in collecting loose logs. An equivalent of 140 truckloads of logs have been salvaged in the last year.
| Date | Location | Study Conducted By | Findings |
|---|---|---|---|
| Late 19th Century | Western shores of B.C. and Haida Gwaii | University of Victoria | 520% increase in drift logs |
| Recent Study | Cowichan Estuary | B.C. Conservation Foundation | Log booms hurt salmon survival |
