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Fractal index captures the role of vegetation clumping in locust swarming
Article first published online: 9 JUN 2003
DOI: 10.1046/j.1365-2435.2003.00728.x
Additional Information
How to Cite
Despland, E. (2003), Fractal index captures the role of vegetation clumping in locust swarming. Functional Ecology, 17: 315–322. doi: 10.1046/j.1365-2435.2003.00728.x
Publication History
- Issue published online: 9 JUN 2003
- Article first published online: 9 JUN 2003
- Received 4 April 2002; revised 18 October 2002; accepted 4 November 2002
- Abstract
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Keywords:
- Aggregation;
- box-counting method;
- discontinuous plant cover;
- dispersion;
- spatial statistics
Summary
- 1This paper evaluates box-counting dimension as a quantitative clumping index for discontinuous plant cover, and applies it to studies of both small- and large-scale ecological processes in desert locust (Schistocerca gregaria) swarming.
- 2The quadrat under study is tiled with squares of increasing size, and the relationship between the number of occupied squares and square size gives the box-counting dimension. This index is high for random distributions and decreases when the vegetation is clumped; it is also positively linked to the abundance of vegetation.
- 3At the scale of individual locusts, this index captures the space-filling properties of vegetation that promote change to the gregarious phase and the onset of swarming. At the very large scale, box-counting dimension measured from satellite imagery reflects topography, which influences the concentration and migration of locust swarms.
- 4Fractal geometry considers scale of measurement in quantifying pattern and provides a framework to interpret ecological phenomena across spatial scales. Demonstration of a statistically significant relationship between the box-counting exponent and locust behaviour shows how this approach can be applied to ecological studies.