ENVIRONMENTAL PARASITOLOGY - WHAT CAN PARASITES TELL US ABOUT HUMAN IMPACTS ON THE ENVIRONMENT

There are a variety of ways that environmental changes affect parasite s, suggesting that information on parasites can indicate anthropogenic impacts. Parasitism may increase if the impact reduces host resistanc e or increases the density of intermediate or definitive hosts. Parasi tism may decrease if definitive or intermediate host density declines or parasites suffer higher mortality directly (eg. from toxic effects on parasites) or indirectly (infected hosts suffer differentially high mortality). Although these scenarios are opposing, they can provide a rich set of predictions once we understand the true associations betw een each parasite and impact. In this review, Kevin Lafferty discusses how parasite ecologists have used and can use parasites to assess env ironmental quality.