Abstract
1 The fine-scale spatial patterns of Agrostis stolonifera, Holcus lanatus and Lolium perenne were recorded in an English lowland grassland as presence/absence maps from 400-cell quadrats at two different scales (2 x 2 cm or 8 x 8 cm cells).
2 Local spatial structure in these patterns was quantified using spatial covariance functions. Distance- and direction-dependent components were examined separately for both intra- and interspecific patterns. The significance of departures from randomness was determined using Monte Carlo techniques.
3 The smaller-scale data showed that all three species were significantly aggregated, Agrostis to a greater distance (8 cm) than Holcus or Lolium (4 cm). The intensity of aggregation decreased in the order Lolium > Holcus > Agrostis. The larger-scale data suggested that this aggregation extended to greater distances, and that it was most intense in Agrostis.
4 Despite the lack of visual directionality in the environment, Agrostis showed a directional pattern at both scales, with Lolium varying in the same direction at the larger scale.
5 Only Agrostis and Lolium showed a significant interspecific relationship (segregated to 2 cm at the small scale, but aggregated to 8 cm at the larger scale). There was no evidence of directionality in the interspecific components of pattern.
6 The nature of spatial structure appears to depend on the scale of observation, but the smaller-scale data are more likely to provide a biologically interpretable measure of local spatial structure in this community.
| Original language | English |
|---|---|
| Pages (from-to) | 121-129 |
| Number of pages | 9 |
| Journal | Journal of ecology |
| Volume | 90 |
| Issue number | 1 |
| Publication status | Published - Feb 2002 |
Keywords
- anisotropy
- plant community dynamics
- spatial aggregation
- spatial covariance functions
- spatial pattern
- SOIL HETEROGENEITY
- MOMENT EQUATIONS
- WHITE CLOVER
- PATTERN
- VEGETATION
- COMPETITION
- DYNAMICS
- MODELS
- ORGANIZATION
- DEPENDENCE