Work to address impaired fish and wildlife habitat is central to Great Lakes Remedial Action Plans. A per-requisite in this work is knowing how much habitat is necessary to support a particular wildlife population.
To help answer this question Environment Canada produced the document “How Much Habitat is Enough? – (3rd edition, 2013)” (available here). The document describes the minimum amount of wetland, forest, riparian and grassland habitat needed to support populations of wildlife. The report also provides an extensive literature review and 21 habitat guidelines to assist land planners and other conservation practitioners to restore and protect wildlife habitat.
Guidelines include: 30% to 50% minimum forest cover, the greater of 10% wetland cover per watershed or 40% of historic wetland cover, 75% of the length of a stream naturally vegetated, less than 10% impervious cover in a watershed, and average grassland patch sizes of greater than or equal to 50 hectares. This publication has influenced land use planning, restoration projects and land purchase initiatives across multiple jurisdictions and has become a standard conservation biology and landscape ecology reference.