What is a common effect of excessive flooding on river ecosystems?

Excessive flooding can have significant impacts on river ecosystems, particularly by disrupting animal habitats. When a river floods, it alters the landscape, inundating areas that are normally dry and possibly washing away or burying vegetation that serves as habitat for various species. The sudden influx of water can lead to a lack of stability in the environment, displacing animals from their homes and disrupting breeding and feeding patterns.

Additionally, flooding may introduce contaminants and debris into the ecosystem, further stressing animal populations. While some plants may benefit from increased water and nutrient availability after a flood, the immediate disruptions to animal habitats can have far-reaching consequences for biodiversity and ecosystem balance.

The other options do not encapsulate the primary impact of excessive flooding as effectively as this one. For instance, while flooding can promote certain types of growth, it is often more impactful on animal life. Claims about water levels being permanently raised or sediment supply being decreased don’t accurately reflect the immediate and recognizable effects of flooding in river ecosystems.