The basis of land management is founded in the science of ecology. Ecology is the study of organisms and their relationships with the biotic (living) and abiotic (physical) environments. Applied ecology is the use of ecological principles and knowledge to manage land and waters.

The ecosystem is the biotic community and its interacting physical environment. The ecosystem can also be described as an energy-processing and nutrient-regenerating system. When viewing the landscape, people tend to categorize the landscape into various ecosystems—forest ecosystems, riparian ecosystems, grassland ecosystems, etc. However, each of these "ecosystems" is really part of a greater ecosystem that has no defined boundaries. Riparian ecosystems interact with the surrounding uplands.

Don't think of the landscape as different ecosystems, but simply one ecosystem with interdependent parts.

To emphasize interactions and holism we will be referring to one ecosystem, and will speak in terms of different environments or habitats, all of which function through four fundamental processes.

The Water Cycle: The existence and movement of water on, in, and above the Earth, between the atmosphere, land, water bodies, and soil. Earth's water is always in movement and changing states, from liquid to vapor to ice. The water cycle—a physical process—including the movement and changing state of water affects plant and animal (including human) life.

The Mineral Cycle: The movement of minerals or nutrients including carbon, nitrogen and other essential nutrients. This physical cycle affects plant, animal and human life.

Energy Flow: The most basic physical processes within an ecosystem are photosynthesis and decomposition. Energy flow describes the movement of energy from the sun through all living or once living things.

Community Dynamics: Ecosystems, plant and animal communities are ever changing. Community dynamics, a biotic process, describes the never-ending development of biological communities.