Plant
Community Structure Across a Nothofagus Treeline Ecotone
In
this project we examined whether the existence of some commonly suggested
features
of ecotones are dependent on the spatial scale (i.e., spatial grain)
at which they are examined. We chose an ecotone comprising a sharp
altitudinal treeline between Nothofagus forest and subalpine
grassland/shrubland in the Longwood Range, South Island of New Zealand,
and sampled vegetation at five scales (i.e., spatial grains). We aimed
to determine which features of ecotones exist at which scales, examining
species richness, the presence of exotic species, and community heterogeneity
as indicated by dissimilarity and species-area relations. Patterns
of plant species richness were largely scale-independent, with species
richness lowest in the forest community, intermediate in the ecotone,
highest a short distance into the shrubland, and lower again in the
shrubland further from the ecotone. High richness just into the shrubland
was attributed to the existence of a fine-scale spatial mosaic pattern
of vegetation. Exotic species were absent in the forest, but occurred
sparsely in the ecotone and in the shrubland. The ecotone community
was the most heterogeneous (indicated by higher dissimilarity values
and a steeper species-area slope), with the forest the least heterogeneous
and the shrubland intermediate.
Keywords:
Community structure, ecotone, spatial scale, species-area relations,
species richness, vegetation.
Publication:
- Stowe, C.J.,
Kissling, W.D., Ohlemüller, R. & J.B. Wilson (2003):
Are ecotone properties scale-dependent? A test from a Nothofagus
treeline in southern New Zealand. Community Ecology 4: 35–42.
[Abstract]
Figure
- Vegetation sampling in the Longwood Range, South Island of New Zealand
(left: Chris Stowe, right: Bastow Wilson).
