Beavers are one of nature's most industrious engineers. Using branches and mud, the intrepid animals create dams that slow moving water. In New York's Hudson Valley, their constructions are a common sight on streams and in wetlands.
Beavers, once valued for their fur, may soon have more appreciation in the Northeastern United States. There they are helping prevent harmful levels of nitrogen from reaching the area's vulnerable estuaries. By creating ponds that slow down the movement of water, they aid in removing nitrogen from the water.
Bags of garden fertilizer are labeled with three numbers, such as 15-4-5. These numbers indicate the percent of nitrogen, phosphorus, and potassium in the product. The remainder of the bag is filler that helps the fertilizer disperse.