The following passage is adapted from a 2021 essay on urban ecology. The author examines how cities have begun to function as ecosystems in their own right, supporting biodiversity in unexpected ways.

For decades, ecologists assumed that urbanization was inherently hostile to wildlife. Concrete landscapes, noise pollution, and artificial lighting seemed to preclude any meaningful biodiversity. Yet recent field surveys have complicated this assumption considerably. In cities from Berlin to Singapore, researchers have documented hundreds of species adapting to urban environments with remarkable speed.

What accounts for this unexpected resilience? Biologists point to several factors. Urban heat islands extend growing seasons, allowing plant species from warmer climates to establish themselves. Reduced predation pressure benefits smaller mammals and birds. Perhaps most significantly, the patchwork structure of city landscapes — parks, gardens, rooftops, abandoned lots — creates a mosaic of microhabitats unavailable in more uniform rural settings.

The implications for conservation are considerable. If cities can support viable populations of native species, urban planning becomes a legitimate tool of ecological policy. Some municipalities have already begun designing "wildlife corridors" — strips of vegetation connecting green spaces across otherwise impermeable urban fabric.