What aspect of rivers supports biodiversity?

The aspect of rivers that supports biodiversity most significantly is habitat provision. Rivers create a variety of ecosystems and microhabitats that foster diverse communities of plants and animals. The flowing water, along with features such as pools, riffles, and vegetation along banks, all contribute to creating different ecological niches. These various habitats provide food, shelter, and breeding grounds for a wide range of organisms, from fish and amphibians to invertebrates and plants. The dynamic nature of rivers allows for a flow of nutrients and energy, critical for supporting complex food webs and maintaining healthy, diverse ecosystems.

While water temperature regulation can influence species distribution and metabolism, it mainly impacts the organisms present rather than creating diverse habitats. Similarly, although recreational usage can provide benefits for human enjoyment and awareness of nature, it doesn't inherently contribute to the ecological aspects that promote biodiversity. Pollution from urban runoff negatively affects water quality, harming the organisms that depend on healthy river environments, and diminishes overall biodiversity. Therefore, habitat provision is the most direct and vital facet of rivers that promotes and sustains biodiversity.