Land reclamation canals (drainage canals) are the most abundant type of water bodies found in the agricultural landscape in Lithuania. Beavers have a potential to improve the ecological value of these artificial habitats; however, little is known about the extent and mechanisms of the process. Our study describes and quantifies some morphological aspects of beaver impact on land reclamation canals under the conditions of a high beaver density. Through damming activity, beavers impacted about 18% of the total length of the drainage canals in our study area, producing impoundments with a mean water area of 0.4 ha per beaver site. Their intensive burrowing activity (ca 36.4 burrows/km) can initiate geomorphologic processes on canal slopes and provide reliable underground infrastructure conditions for other species. From one average burrow beavers can potentially release about 1.3 m3 of soil (sediment). The microrelief variations were significantly more pronounced in canal segments occupied by beavers than in the control segments. Transformations of drainage canals induced by beaver activity improve the ecological value and lead to re-naturalization of these artificial water bodies.
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