Skip to main content

Linking abundance, occupancy and spatial structure: an empirical test of a neutral model in an open-forest woody plant community in eastern Australia

Buy Article:

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.


We implemented a neutral model of a positive relationship between abundance and distribution (occupancy) to examine how spatial structure influences abundance–occupancy relationships. The spatially explicit neutral model distributes individuals of species randomly and independently of one another in space to produce a positive abundance–occupancy relationship. Using empirical data, we tested whether abundance–occupancy relationships diverged significantly from the theoretical neutral model, and determined whether significant divergences emerged through intraspecific aggregation or over-dispersion of individuals.Location

Field work was conducted in open-forest vegetation of the Black Mountain region in south-eastern Australia.Methods

At eight floristically similar sites in open-forest vegetation, we established a 20 × 20 m census plot and spatially mapped all individuals of each woody species. The abundance and distribution of each species was determined at each site at three spatial scales within the census plot. Observed abundance–occupancy relationships were compared with the spatially explicit neutral model using linear regression techniques. Monte-Carlo methods using a two dimensional Poisson process were then used to classify the spatial structure of species as random, aggregated or over-dispersed.Results

We found consistent evidence among the eight sites for abundance–occupancy relationships to diverge significantly from the neutral model at the three spatial scales within each community. The direction that the slopes of relationships diverged from the neutral model provided consistent evidence that aggregation of individuals within species was responsible for modifying the form of abundance–occupancy associations in this vegetation, a feature most evident with increasing scale.Main conclusions

Aggregation is not a mechanism that causes positive abundance–occupancy relationships. Under the neutral model of a positive abundance–occupancy relationship, aggregation should be viewed as a mechanism which modifies a pre-existing relationship, rather than causing a relationship which would not have otherwise existed. In other words, in the absence of aggregation a positive abundance–occupancy relationship would still exist.
No References
No Citations
No Supplementary Data
No Data/Media
No Metrics

Keywords: Abundance; density; distribution; null model; occupancy; spatial structure

Document Type: Miscellaneous

Publication date: 2001-03-01

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more