The ecology of bryofauna in northern, coastal Labrador, Canada: a study of the effects of elevation, moss depth, seasonality and latitude on moss fauna distribution patterns

Boeckner, Matthew James (2003) The ecology of bryofauna in northern, coastal Labrador, Canada: a study of the effects of elevation, moss depth, seasonality and latitude on moss fauna distribution patterns. Masters thesis, Memorial University of Newfoundland.

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Abstract

Nematodes, tardigrades, bdelloid rotifers, oribatid mites and collembolans (the dominant bryofauna) were obtained and identified from the moss species Dicranum polysetum at various elevations within 3 towns of northern, coastal Labrador, Canada: Nain, Hopedale and Makkovik. A preliminary field collection took place in October, 2001 followed by 2 further collections in June and August, 2002 which focused more on quantitative data. Twenty three nematode genera, 18 tardigrade species, 3 rotifer genera, 15 oribatid mite genera and 1 collembolan genus were identified during the study. All findings were new records for Labrador and many were significant national discoveries. -- A quantitative sampling design and multivariate analyses (non-metric multidimensional scaling) were used to examine differences in bryofaunal community structure across 4 environmental gradients: elevation, horizon depth/desiccation tolerance, seasonality and latitude. The nematodes contributed the most to understanding how variable environmental gradients affect bryofauna community structure as they had the greatest relative abundance throughout the study. The tardigrades and oribatid mites also exhibited some significantly variable distributions with regard to the environmental parameters, although fewer total specimens represented them. Bdelloid rotifers and collembolans were not quantitatively analyzed due to extremely low representation in the dataset. -- It was determined that moss horizon depth had the greatest effect on nematode, tardigrade and oribatid mite distributions. In some cases elevation and seasonality also accounted for much of the variability in bryofaunal distribution patterns but results were often variable between geographic locations. The effect of latitude on distribution patterns did not show any significant relationship to bryofaunal distribution and was likely too small of a gradient to greatly affect the bryofaunal communities. -- Some biotic relationships between bryofaunal groups were inferred and the general application of the moss fauna as a biological indication system was evaluated. Additionally, guidelines were given for the use of such an indicating system that would result in optimal effectiveness.

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