Parasites and ecosystem health

5 downloads 0 Views 44KB Size Report
Preface. Parasites and ecosystem health. One of the ironies of parasitological research over recent decades is that at the very time when non-parasitologists are.
International Journal for Parasitology 35 (2005) 703 www.parasitology-online.com

Preface

Parasites and ecosystem health One of the ironies of parasitological research over recent decades is that at the very time when non-parasitologists are discovering the value of parasitic organisms as models to investigate fundamental questions in ecological and evolutionary theory, parasitologists themselves have largely shifted their focus to a reductionist study of the treatment and control of parasitic diseases. This shift in focus has, of course, been driven to a large extent by societal needs and by the realities of research funding, but we should not lose sight of the fact that the study of the fascinating life cycles of parasites in natural ecosystems has much to offer. This may be especially true in the newly emerging field of ecosystem health, which is concerned with measuring and controlling the effects of human influences on natural ecosystems. The 46th Annual Meeting of the Australian Society for Parasitology, held in Fremantle, Western Australia, convened a symposium on the topic of Parasites and Ecosystem Health. The papers from this symposium, offering three different perspectives on the topic, are presented in this issue of the International Journal for Parasitology. Parasites are an integral part of natural ecosystems, and Dave Marcogliese in his paper explains how a careful study of parasites can inform our understanding of food web structure and ecosystem diversity. This suggests that parasites may serve as indicators for environmental stresses, which affect these elements of ecosystem function. The key to utilising parasites as bioindicators, however, is a thorough knowledge of parasite biology, at the population, guild and community levels. A particular example of the way in which human influences on ecosystems can alter the dynamics of parasite transmission is the concept of emerging infectious diseases, which can often be viewed as a consequence of disrupted

0020-7519/$30.00 doi:10.1016/j.ijpara.2005.02.012

ecosystems. Dave Spratt examines a range of newly emerged diseases of people and other animals, which have arisen as a result of human interruption of natural food chains in Australia. Understanding the aetiology of these new diseases requires a detailed understanding of the natural transmission cycle of the parasite; something that we have for all too few parasites of native animals in Australia. The final paper in this series, by Pierre Horwitz and Bruce Wilcox, views host–parasite relationships within the context of complex, self-organising systems. This perspective leads to new insights about how the dynamics of parasite transmission are affected by processes operating at vastly different temporal and spatial scales. It also leads us to consider more closely the benefits, as well as the costs, of parasitic infection, at the levels of the individual host, a population of hosts, and an entire ecosystem. Horwitz and Wilcox argue that a systems perspective on host–parasite relationships is required in order to develop sustainable parasite control strategies. The three papers in this series provide a fascinating insight into the complexities of parasite life cycles in natural ecosystems, and the causal connections that their study can elucidate. I would like to thank all the contributors for their willingness to participate in the symposium on Parasites and Ecosystem Health, and for their enthusiastic and open sharing of their knowledge and ideas. Alan J. Lymbery* Fish Health Unit, School of Veterinary and Biomedical Sciences, Murdoch University, Perth, WA 6150, Australia E-mail address: [email protected]

* Tel.: C61 08 9360 2729; fax: C61 08 9310 4144.