Complex sentence: In some cases, these have become invasive species that compete with native fishes or disrupt the environment, carp in particular can stir up the riverbed reducing the clarity of the water making it difficult for plants to grow.
Split into simpler sentences: In some cases, these have become invasive species that compete with native fishes or disrupt the environment. Carp in particular can stir up sediment, reducing the clarity of the water and making it difficult for plants to grow.