Our environment is changing at an incredible rate. Whether this change is a consequence of natural cycles, human induced, or a combination of both factors, it can be said with certainty that we are losing biodiversity faster than we can catalogue it. Well-publicized efforts are underway to document, monitor and possibly manage the mega-flora and fauna on earth. But the majority of life on the planet is comprised of microbes and microscopic organisms too small to see, but too important to ignore. Nematodes, for example, are the most abundant multi-cellular animals on earth. They fill critical roles in aquatic and terrestrial ecosystems and have significant impacts on agriculture, veterinary medicine and human health. High profile pest species like the potato cyst nematode and human hookworm receive attention because of their direct measurable impact on human welfare. Yet an estimated 95% of the species are unknown and expertise in nematode identification has diminished to a handful of professionals who actively describe nematode diversity.
Criconematina are a major group of plant-parasitic nematodes found in soils from the tropics to the arctic. They typically exhibit relative wide host ranges feeding on plants as diverse as redwoods and moss. They have an exceptionally high level of endemicity; nearly 70% of the species known from New Zealand have only been recovered in that country (Wouts, 2006). Their high endemicity, poor dispersal capabilities, and apparent lack of specialized survival stages make them an excellent subject for biogeographic analysis. They are potential indicators for soil disturbance (Bernard, 1992). While a few species appear to be adapted to disturbances associated with agricultural production, the vast majority are confined to native habitats with a relatively stable soil structure (Bernard, 1982; Hoffman and Norton, 1976; Peneva et al., 2000). It is theoretically possible that high-resolution DNA profiles of Criconematina across North America could provide a genotypic fingerprint of sufficient distinction to allow identification of habitats based on their DNA.
This project is an effort to describe Criconematina nematodes on a global scale. In the process we hope to provide a greater appreciation for the complex and highly structured communities of organisms found in every square meter of soil. E.O.Wilson has remarked “We live in a nematode world” (Seely, 2000). Nathan Cobb famously commented on a dimly recognizable world if all matter except nematodes were removed (Cobb, 1915). Both men could have gone further, presenting an image of a global veneer of nematodes that in its species composition and genetic makeup reflects the movement of continents over hundreds of millions of years as well as the comparatively recent postglacial recolonization that followed the Ice Ages (Pielou, 1991).