A Beautiful Transformation
In 2014, we began a grassland restoration project at Upper Credit Conservation Area. The goal was to convert seven and a half hectares of an old farm field to a native, tallgrass prairie ecosystem.
In the years since, we have been monitoring the site’s vegetation community as it transitions from a meadow dominated by non-native species into a thriving native grassland. Staff perform maintenance activities to ensure the site continues to develop towards the target tallgrass prairie ecosystem. Monitoring includes:
- Mowing sections to keep undesirable plants from growing.
- Overseeding with native seeds to increase diversity.
- Removing invasive plant species that threaten to overtake the grassland.
- Conducting bird surveys during the breeding season to monitor how birds are using the site. We’re taking note of any species-at-risk such as bobolink and eastern meadowlark that are nesting on-site.
Benefits of Prescribed Burns
In April of 2021, we worked with contractors to undertake a prescribed burn of the Upper Credit grassland. We coordinated with local police, fire services and municipal staff to ensure the public was informed. Safety protocols were put in place such as installing fire breaks before the burn was started and carefully monitoring the area as it burned.
Without a periodic disturbance such as a fire, grasslands in Ontario will naturally return to shrublands and then to forests. Native grasslands provide different benefits compared to forests as they form habitat for pollinators and wildlife that prefer open areas. Restoration practitioners manage grasslands to preserve these ecosystems benefits.
Tallgrass prairie ecosystems are made up of warm-season grasses such as:
- Big bluestem (Andropogon gerardii)
- Indiangrass (Sorghastrum nutans)
- Switch grass (Panicum virgatum)
These grasses grow during the warmer months of the year, forming bunches rather than continuous sod conditions. The space between these bunches provides important habitat for ground nesting birds, like bobolink.
Tallgrass prairies are at risk of invasion by non-native, sod-forming grasses such as smooth brome (Bromus inermis) and quackgrass (Elymus repens). These grasses grow in the spring and fall when native grasses are dormant.
A well-timed prescribed burn in the spring will interrupt the growth of brome and quackgrass and not impact the desired warm season grasses.
Controlled fires clear away debris and the blackened earth absorbs heat from the sun, which warms the soil and encourages growth from the warm season grasses. This extends their growing season and gives them an advantage in subsequent years. Fire also eliminates any trees or shrubs that have begun to grow, ensuring that the site remains a grassland.
Monitoring activities since the burn have shown positive results. The coverage of native species seeded at the site increased by 30 per cent from 2020 to 2021.
In 2022, we found an increase of native species. Twenty of the 21 native species seeded were found. This result indicates successful restoration efforts. Big bluestem and Indiangrass were found to be the most abundant grasses in the monitoring plots.
During our 2022 bird surveys, we recorded nine adult bobolink, the second highest number since post-restoration monitoring began in 2013! This was in addition to four juveniles which likely fledged from a nest in the restored grassland.
The monitoring results indicate that the burn has contributed to the site’s development into a mature native grassland. Many native grasses and wildflowers are now in bloom, making it a great time to visit Upper Credit Conservation Area.
By Aaron Root, Technician, Terrestrial Restoration