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March 01, 2024

Monarch Butterflies: A Species at Risk in Ontario

In the landscapes of southern Ontario, the monarch butterfly, renowned for its vibrant orange and black wings, faces the threat of extinction. Once a common sight across the province, these butterflies are now declining in numbers at a rate that is raising concerns among environmentalists and conservationists.

CNL has long protected the monarch, and its habitat, which sits on the Species-At Risk database for Port Hope Area Initiative (PHAI) work. CNL and our contract partners carefully monitor all PHAI sites for the listed species and their habitats.  We then avoid or manage interaction where project construction and remediation activities are planned or underway.

We realize that the main issue contributing to the decline of these butterflies in Ontario is the loss of essential breeding and feeding grounds. Milkweed, the sole food source for monarch caterpillars, has been significantly depleted due to urbanization, agricultural expansion, and land development. As a result, monarchs struggle to find suitable habitats to lay their eggs and sustain their population.

Collaborative efforts from companies like CNL, government agencies, conservation organizations, farmers, and local communities are essential for protecting habitats, implementing restoration projects, and promoting sustainable land management practices.

In 2023, during PHAI work at the Viaducts, a private property owner worked with CNL to ensure a monarch butterfly habitat was preserved, and designs were revised. At other sites across the Port Hope community, milkweed and other native plantings are being used in restoration plans.

Monarch butterflies revered for their beauty and the significant ecological role they play as pollinators have now been added to the endangered list, under Canada’s Species at Risk Act (SARA). This designation gives endangered or threatened species additional protection on federal lands, making it an offence to kill, harm or damage a species residence.

Residents can help sustain monarchs and other pollinators by planting milkweed and other native wildflowers in their yard or flowerbed.

See database of species proactively identified as protected during PHAI work

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