In this volume, 25 scientists from around the world review the most recent advances in the study of how frogs and toads communicate. The contributors - who are experts in disciplines including animal behaviour, developmental biology, endocrinology, evolution, ecology and neurobiology - examine this amphibian order's vocal, visual and chemical signals, the physiology and energetics of their production, neural processing, related behaviours, and evolutionary implications. As the chapters demonstrate, research developments have led to further understanding of the role of the anuran larynx in sound production, how the anuran brain recognizes sound, and how both of these processes are influenced by the animal's physiological state. The contributors also discuss male-to-male call strategies as well as how female preferences for call variation contribute to sexual selection, speciation and hybridization. The text presents material about kin recognition abilities and the surprising range of visual displays by tropical anurans, and examines how the inherent structure of the auditory system might generate sensory biases that influence signal evolution.

Biodiversity, sometimes simply understood as "diversity of species", is a specific quality of life on our planet, the dimensions and importance of which have just lately been fully realized. Today we know that "biological diversity is a global asset of incalculable value to present and future generations" (Kofi Annan). Biodiversity is spread unequally over the world: in fact, the main share of biological resources worldwide is harboured predominantly by the so-called developing countries in the tropics and sub tropics. Therefore, Biodiversity - A Challenge for Development Research and Policy was chosen as the title for an international conference which was held in Bonn in 1997 as one of the first major events organized by the then newly established North-South Centre for Development Research (ZEF) at Rheinische Friedrich-Wilhelms-Universitat Bonn (Germany). Since the ZEF, founded by the Senate of the University of Bonn in 1995, has played a central role in turning Bonn into a centre for international cooperation and North-South dialogue. The Centre is a product of the Bonn Berlin agreement of July 1994 which was adopted to offset the effects caused by the Parliament and much of the Government moving to Berlin. It fits in well with the double strategy to strengthen Bonn's position as an interna tional science arena and as an eminent place for development policy and the national and supranational agencies dealing with this issue.

Growing human populations and higher demands for water impose increasing impacts and stresses upon freshwater biodiversity. Their combined effects have made these animals more endangered than their terrestrial and marine counterparts. Overuse and contamination of water, overexploitation and overfishing, introduction of alien species, and alteration of natural flow regimes have led to a 'great thinning' and declines in abundance of freshwater animals, a 'great shrinking' in body size with reductions in large species, and a 'great mixing' whereby the spread of introduced species has tended to homogenize previously dissimilar communities in different parts of the world. Climate change and warming temperatures will alter global water availability, and exacerbate the other threat factors. What conservation action is needed to halt or reverse these trends, and preserve freshwater biodiversity in a rapidly changing world? This book offers the tools and approaches that can be deployed to help conserve freshwater biodiversity.

Environmental Aspects of Zoonotic Diseases provides a definitive description, commentary and research needs of environmental aspects related to zoonotic diseases. There are many interrelated connections between the environment and zoonotic diseases such as: water, soil, air and agriculture. The book presents investigations of these connections, with specific reference to environmental processes such as: deforestation, floods, draughts, irrigation practices, soil transfer and their impact on bacterial, viral, fungal, and parasitological spread. Environmental aspects such as climate (tropical, sub-tropical, temperate, arid and semi-arid), developed and undeveloped countries, animal (domestic and wild) traffic animal border crossing, commercial animal trade, transportation, as well geography and weather on zoonosis, are also discussed and relevant scientific data is condensed and organized in order to give a better picture of interrelationship between the environment and current spread of zoonotic diseases. Altogether, the book presents a remarkable and a vast amount of potential future research directions based on the link: environment-vectors-pathogens-humans. The most up-to-date source of information on this increasingly important cross-disciplinary subject, Environmental Aspects of Zoonotic Diseases will be invaluable for environmentalists, veterinarians, medical staff, environmental engineers, government agencies and consultants working in this field. Authors: Prof. Robert Armon, Technion (Israel Institute of Technology), Haifa, Israel, Dr. Uta Cheruti, Technion (Israel Institute of Technology), Haifa, Israel