destroyed by human activities as well as developing ecosystems that are sustainable with both human and ecological values. Examples Terrestrial environments Besides the previously mentioned beaver acting as an ecosystem engineer, other terrestrial animals do the same. This may be through feeding habits, migration patterns or other behaviors that result in more permanent changes. Research has suggested primates as ecosystem engineers as a result of their feeding strategies – frugivory and folivory – making them act as seed dispersers. As a whole primates are very abundant and feed on a large quantity of fruit that is then distributed around their territory. Elephants have also been designated ecosystem engineers as they cause very large changes to their environment whether it be through feeding, digging or migratory behavior. Prairie dogs are another terrestrial form of allogenic ecosystem engineers due to the fact that the species has the ability to perform substantial modifications by burrowing and turning soil. They are able to influence soils and vegetation of the landscape while providing underground corridors for arthropods, avians, other small mammals, and reptiles. This has a positive effect on species richness and diversity of their habitats which results in the prairie dogs being labelled as keystone species. Arthropods can also be ecosystem engineers, such as spiders, ants, and many types of larvae that create shelters out of leaves, as well as gall-inducing insects that change the shapes of plants. Bark beetles are an ecosystem engineer of forest ecosystems and can affect fire spread and severity when attacking their host pine species. Not only animals are ecosystem engineers. Fungi are able to connect regions that are distant from one another and translocate nutrients between them. Doing so they create nutritional niches for xylophagous invertebrates, supply trees with nitrogen translocated from previously predated animals or even form an "underground pipeline" that redistributes carbon between trees. Thus fungi are engineers controlling nutrient cycles in ecosystems. Marine environments In marine environments, filter feeders and plankton are ecosystem engineers because they alter turbidity and light penetration, controlling the depth at which photosynthesis can occur. This in turn limits the primary productivity of benthic and pelagic habitats and influences consumption patterns between trophic groups. Another example of ecosystem engineers in marine environments would be scleractinian corals as they create the framework for the habitat most coral-reef organisms depend on. Some ecosystem engineers such as coral have help maintaining their environment. Parrotfish