TerrestrialPortugal

On land, many different organisms affect the creation, movement and deposition of sediments and the sculpting of rock outcrops. As well as mixing soil and helping cycle nutrients, animals that dig and burrow contribute to landform creation, and make sediment available to subsequent erosion by wind and water. This includes a whole host of animals such as gophers, ants and termites, badgers, moles and porcupines. In environments such as arid and semi-arid scrublands, disturbance of the soil by animals can be critical in the health of the ecosystem. In this way both geomorphologists and ecologists are interested in measuring these processes.

Plants are equally important for soils. Not only does plant matter add nutrients to the soil as it decomposes, vegetation can increase the deposition of sediment and stabilise it. This includes grasses that grow on sand dunes near the coast and in deserts. Even microorganisms can stabilise sand by covering the surface in ‘biocrusts’, protecting sand and soil from the wind.

RiverIn rivers, living vegetation (‘macrophytes’) slows down water and can encourage sediment deposition as well as promoting scour. Animals such as crayfish and fishes also move and mix sediment in rivers, just as burrowing and digging animals do on land. Dead woody material is also very important in many river systems, affecting river and floodplain shape and how these change over time. Understanding biogeomorphological interactions in rivers is extremely useful for habitat restoration.