Continuum of Wildland to Urban Densities

All of Earth’s ecosystems are directly or indirectly impacted by humans. But landscapes where people live, work, and travel can become dominated by people, such that the built environment and people’s daily activities control major ecological processes. Cities, factories, and airports still have plants, animals, and ecosystems in and around them, but how animals move around, where plants can grow, and how water moves through the system are inextricably linked to human developments.  

Human-dominated ecosystems can include: 

• Urban: areas with human population densities >1,500 people per km2 

• Suburban: areas with human population densities of >300/km2.  

• Urbanizing: areas where human populations are increasing to suburban and urban densities 

• Wildland Urban Interface: where people directly abut natural areas