What environmental impact is generally considered the most significant when performing an EIA for highway construction?

Habitat fragmentation is generally considered the most significant environmental impact when performing an EIA for highway construction. Highway construction often involves clearing large areas of land, which can fragment existing habitats, dividing them into smaller, isolated patches. This fragmentation can disrupt wildlife movement patterns, reduce access to food and water resources, and decrease genetic diversity within populations. Habitat fragmentation also increases the edge effect, where the boundary between the habitat and the surrounding landscape experiences altered environmental conditions, such as increased sunlight, wind, and invasive species. These effects can negatively impact the species that rely on these habitats, leading to population declines or even local extinctions. For example, a highway bisecting a forest can prevent animals from migrating between different parts of their range, isolating populations and making them more vulnerable to environmental changes and diseases. The loss of continuous habitat can have cascading effects on the entire ecosystem, altering species interactions and ecosystem functions.