Ecosystem
An ecosystem is a dynamic complex of plant, animal, and microorganism communities interacting with one another and with their non-living environment as a functional unit. Its boundaries depend on the purpose of analysis and may range from a pond or forest patch to a river basin or ocean region.
In simple terms
An ecosystem includes organisms, physical conditions, and the exchanges connecting them: energy flows, food webs, nutrient cycles, water movement, disturbance, and recovery. Boundaries are analytical rather than walls in nature, so adjacent ecosystems can exchange organisms and materials. Ecosystem condition describes characteristics such as composition, structure, function, and integrity. Changes to one part, including water availability or a key species, can alter other parts and the ecosystem services the system contributes.
Why it matters
Thinking in ecosystems reveals biodiversity dependencies and side effects that single-species or site-only analysis can miss. It helps explain why land conversion upstream may influence water quality downstream, why habitat connectivity matters, and why protecting isolated features may not preserve the processes people and wildlife rely on.
Example
For example, a mangrove ecosystem includes trees, fish, birds, microbes, tidal water, sediments, salinity, and the interactions among them. Assessing only tree cover would overlook nursery habitat, sediment processes, water exchange, and the condition of the wider coastal system.
How it differs
Ecosystem services
An ecosystem is the interacting ecological system itself; ecosystem services are the ecosystem contributions that people use or value.