Ecosystem engineers are organisms that significantly modify their environment, creating habitats for other species. They can be plants, animals, or even microorganisms. For example, beavers build dams that create ponds, which provide homes for various aquatic life and help maintain water levels in surrounding areas. These organisms play a crucial role in maintaining biodiversity and ecosystem health. By altering their surroundings, ecosystem engineers influence nutrient cycling, soil formation, and water flow. Other examples include coral reefs, which provide structure and habitat for numerous marine species, and trees, which create shade and shelter for various wildlife.