The beaver (Castor canadensis) is a large, primarily nocturnal semi-aquatic rodent used as an indicator of the conditions in freshwater ecosystems due to its role as a keystone species and an ecosystem engineer. The potential for beaver colonization within Kouchibouguac National Park is considerable due to the quantity of first and second order streams within its borders. In addition, the most important and preferred food source available to beavers in the Park is the trembling aspen (Populous tremuloides); though this tree species colonizes disturbed areas and is usually replaced by conifers or shade-tolerant hardwoods in long-term succession. Hence, the population dynamics of beavers can reflect large-scale changes in forest ecosystems. Beavers are also an important component of biodiversity and ecological integrity because of the positive effects that the creation and maintenance of wetland areas have on a large number of animal and plant species. The purpose of the beaver monitoring program is to determine the total number of active sites in order to evaluate the abundance and distribution of families as an indication of population status. The methods for this measure involve a total ground census of all watercourses, conducted every ten years during the summer months from June to August. Site locations are recorded with a global positioning system along with noticeable signs of beaver activity (e.g., recent maintenance of dam/hut; territorial scent mounds; trails; freshly cut trees, branches or twigs; visual observation). Active sites are each considered as separate families while inactive or abandoned sites are noted but not measured as part of the count.