The Biology of Temporary Waters

Temporary waters are found throughout the world, including intermittent streams and ponds, episodic rain puddles, seasonal limestone lakes, and the water-retaining structures of plants, such as bromeliads and pitcher plants. They are populated by a variety of plant, animal, and microscopic communities ranging from the very simple to the highly complex. As such, they represent fascinating and significant arenas to study the properties of species, as the latter deals with the rigours of living in highly variable environments. Obligate temporary water species display a remarkable array of adaptations to the periodic loss of their primary medium that largely sets them apart from the inhabitants of permanent water bodies. The survival of individuals frequently depends upon exceptional physiological tolerance or effective migrational abilities that are timed to appropriate habitat phases. However, apart from their inherent biological interest, temporary waters are now in the limelight from a conservation perspective as these habitats come more and more into conflict with human activities. Traditionally, many temporary waters — be they ponds, pools, streams, or wetlands — have been considered as ‘wasted’ areas of land, potentially convertible to agriculture once drained. In reality, they are natural features of the global landscape representing distinct and unique habitats for many species — some that are found nowhere else, others that reach their maximum abundance there. Temporary waters are also very important from a human health perspective, since they function as breeding places for the vectors of many disease organisms.