The remote nature of the Hawaiian Islands has resulted in stream ecosystems that lack many of the organisms that are found in continental ecosystems.  In continental streams, these organisms are an important part of the stream community in that they breakdown leaf litter that enters the streams into smaller particles that can be used by other organisms as well as into dissolved forms that can be used by microbial organisms.  The lack of these organisms in Hawaiian streams has resulted in low leaf litter breakdown; much of the leaf litter that enters Hawaiian streams flows into coastal waters.  However, the invasion of riparian forests adjacent to streams by nitrogen(N)-fixing trees has significantly increased the amount of N rich leaf litter entering Hawaiian streams that may provide a more nutritional source of leaf litter for native (or exotic) stream invertebrates.  This could significantly alter the ecological function of Hawaiian streams.

Dr. MacKenzie received his PhD from the University of Wisconsin at Milwaukee, where he studied invertebrate communities in coastal wetlands around Lake Michigan.  He then worked as a post-doc at the Wells National Estuarine Research Reserve studying fish and invertebrates in coastal wetlands along the Gulf of Maine. Since then, he has spent the last 5 years working in streams and wetlands in Hawaii and Micronesia.