Department of Zoology, University of Toronto,. 25 Harbord Street, Toronto, Ontario, Canada M5S IAl
The significance of four xeric parameters in the ecology of terrestrial Tardigrada
Article first published online: 23 MAR 2009
Journal of Zoology
Volume 224, Issue 1, pages 59–77, May 1991
How to Cite
Wright, J. C. (1991), The significance of four xeric parameters in the ecology of terrestrial Tardigrada. Journal of Zoology, 224: 59–77. doi: 10.1111/j.1469-7998.1991.tb04788.x
- Issue published online: 23 MAR 2009
- Article first published online: 23 MAR 2009
- Accepted 29 May 1990
Tardigrades were sampled from diverse biotypes and classified according to four xeric variables to assess susceptibility to desiccation: exposure to insolation, elevation, and standardized desiccation rate and hydration capacity of the habitat plant. Fifteen tardigrade species were recorded including Hypsibius cataphractus Maucci, a new addition to the British fauna.
Xeric associations with seven tardigrade species were analysed by multiple regression, using incidence and population density as independent abundance estimates. Species show considerable variation in ecotype. The hygrophilic Macrobiotus hufelandi and Hypsibius dujar dini are excluded from rapidly desiccating habitats. Xerophiles, Milnesium tardigradum and H. oberhaeuseri, do not favour high insolation or high desiccation rate but apparently shun poorly drained sites and/ or prolonged hydration. Significant interspecific associations are identified between Milnesium tardigradum and two Hypsibius species which it may exploit for food. Negative associations between three other species—M. hufelandi, M. richtersi and H. prosostomus—suggest competitive exclusion.
The interstitial meiofauna of a dehydrating moss cushion migrates vertically to the proximal C-zone, although this behaviour is not observed in Echiniscus testudo; implications of this for the species' ecotype are discussed.