An ecosystem is a community of living organisms (plants, animals, microorganisms) interacting with each other and their physical environment (water, soil, air, climate) as an integrated system. Ecosystems range in scale from a small pond to entire forests or oceans. Each component depends on others—plants produce oxygen and food, animals spread seeds and control populations, decomposers recycle nutrients, and physical conditions determine what can survive. Human activities profoundly impact ecosystems through development, pollution, climate change, and resource extraction. Municipal planning increasingly considers ecosystem services—the benefits healthy ecosystems provide, including clean water, flood control, air purification, and recreation. Environmental assessments evaluate development impacts on local ecosystems, and many municipalities protect significant ecosystems through conservation areas, environmental protection zones, and restoration projects.