A warm hello from the Elephant Hill Wildfire Riparian Restoration team!

Autumn is well underway, bringing cooler winds, warmer colours, and some fresh snow to the trees in the Elephant Hill area.

This summer, field crews from SRSS member communities have been busy collecting data about how vegetation is recovering after the fire, and there have been several project activities that are advancing the restoration of the fire area:

• Mike Dedels from the Thompson-Nicola Regional District Invasive Species Council conducted training with technicians regarding invasive species identification and management
• Bonaparte Natural Resources built 10 Electrical Conductivity-GPS devices in collaboration with UBC to monitor water quality
• 132 field surveys have been completed and are now being used to identify priority areas for restoration and plan for planting activities in Spring/Summer 2021

The Connections between Trees and Fish

Trees provide many benefits to salmon and trout: (1) they provide shade, (2) they provide physical habitat, and (3) they help prevent flooding and erosion which are major problems for fish in the Elephant Hill Fire area. In this newsletter, we are shedding light on why shade is important for fish, particularly at a watershed scale.

Why shade streams?

Salmonids, or fish in the salmon and trout family, are adapted to thrive in cool water and struggle to survive in warmer temperatures. Studies show that sustained temperatures around and above 19° C can be fatal to salmon.

This happens for two reasons. First, fish move around more at higher temperatures, expending energy and requiring oxygen. Second, warmer water holds less dissolved oxygen than colder water. Together, these factors mean that warm water temperatures contribute to fish mortality.

Sunlight warms waterbodies in summer months by contributing radiation directly to the water. Increasing drought periods in the summer and a changing climate make this all the more a dangerous reality. Tree cover intercepts this solar radiation and prevents the most high-energy light from reaching the water. This is, simply, how trees benefit water temperatures for salmon, trout, and other fish. Now, it becomes complicated when one considers how to restore shade over both space and time.

Trees are slow-growing in this part of the world and may take 50-120 years or more to reach their maximum height, depending on the species. Planting trees now means that riparian forests will shade streams in 15 or more years.

Restoring rivers by planting trees

The Elephant Hill Riparian Restoration Project began with a process of looking at post-fire aerial photography to see which streams were most severely burned. These stream reaches are the most likely to not have natural regeneration of trees, as the soil and seed bank in these areas were burned with the trees themselves. By planting these reaches that were most severely disturbed, this project aims to fill in the gaps of forest that will not grow back on its own.

It is particularly important to provide shade to the smaller, tributary streams in a watershed, as they are the fastest to heat up in direct sunlight – though they may not provide habitat for fish themselves. If tributary streams feed warm water into a river across a large area, the temperature may get too high for fish to survive in that main river. This is why we have focused restoration on the headwater streams as well as the mainstem of the Bonaparte and Rayfield Rivers.

At a watershed scale, though the project will not be perfect in restoring riparian forests on all segments of streams, it is our hope that between nature’s hard work and ours, a significant enough portion of the streams in the Bonaparte and Deadman river basins will have riparian forest cover that shades these tributaries and contributes to lower water temperatures throughout the system down to the main river at the valley bottom.

Few projects in the interior of British Columbia have attempted watershed restoration on this scale, as the scale of disturbance from the 2017 and 2018 wildfires was unprecedented. Fewer projects still have focused restoration across a broad area for long-term goals rather than focus on a specific reach of river for habitat enhancement. We hope that this landscape-scale approach will make a difference for the water and fish in these rivers and can be replicated across the region where needed.

We need your help! Do you know of areas within the wildfire area where salmon used to spawn? Are there salmon runs that are important to you, your organization, or your community? Your input will help us identify priority areas for restoration as we move forward with the project.

Staying Connected

As always, we want to hear from you. If you have any questions or comments about anything related to the project – salmon, the Elephant Hill area, plans for restoration, or conditions on the land, you can reach us at info@srssociety.comat any time.

In the meantime, stay safe and take good care.