According to the Swiss-based International Union for Conservation of Nature, Bhutan is viewed as a model for proactive conservation initiatives. The Kingdom has received international acclaim for its commitment to the maintenance of its biodiversity. This is reflected in the decision to maintain at least sixty percent of the land area under forest cover, to designate more than 40% of its territory as national parks, reserves and other protected areas, and most recently to identify a further nine percent of land area as biodiversity corridors linking the protected areas. All of Bhutan's protected land is connected to one another through a vast network of biological corridors, allowing animals to migrate freely throughout the country. Environmental conservation has been placed at the core of the nation's development strategy, the middle path. It is not treated as a sector but rather as a set of concerns that must be mainstreamed in Bhutan's overall approach to development planning and to be buttressed by the force of law. The country's constitution mentions environment standards in multiple sections.