Pesticides reduce biodiversity in rivers and streams

Pesticides commonly used in Europe and Australia are reducing the regional diversity of invertebrates in streams and rivers by up to 42 percent, scientists say. A team of German and Australian researchers analyzed the impact of pesticides, including insecticides and fungicides, on the biodiversity of invertebrates in flowing waters using data from Germany, France and the state of Victoria in Australia. Writing in the U.S. journal Proceedings of the National Academy of Sciences, the researchers said they were able to demonstrate considerable losses in the regional biodiversity of aquatic insects and other freshwater invertebrates. A difference in biodiversity of 42 percent was found between non-contaminated and strongly contaminated areas in Europe, and in Australia, a decrease of 27 percent was determined, the study said. The overall decrease in biodiversity is primarily due to the disappearance of several groups of species that are especially susceptible to pesticides, including stoneflies, mayflies, caddisflies and dragonflies that are important members of the food chain right up to fish and birds, researchers said. A worrying finding of the study is that the impact of pesticides on these tiny creatures is already catastrophic at concentrations that are considered acceptable under current European regulations, they said.