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Characterisation by fractal analysis of foraging paths of ewes grazing heterogeneous swards
- Source :
- Applied Animal Behaviour Science, Applied Animal Behaviour Science, Elsevier, 2005, 93, pp.19-37
- Publication Year :
- 2005
- Publisher :
- HAL CCSD, 2005.
-
Abstract
- On grasslands, herbivores make a trade-off between the quality and the quantity of their intake. They improve their searching efficiency by modulating their foraging velocity and/or their path sinuosity through the perception of their feeding environment. The aim of this study was to test the pertinence of fractal analyses of foraging paths in order to improve the understanding of spatial utilisation at grazing. By the analysis of grazing paths of herbivores grazing a continuously distributed and spatially limited resource, we aimed to identify the spatial scales at which the animals perceive heterogeneity of the sward, and to characterise how sheep modulate their foraging paths through resource abundance and heterogeneity. Two groups of five dry ewes, grazing two plots of contrasting areas from April to the end of September 2000, were studied. On the smaller plot (1500m 2 ), the application of a high stocking rate (HSR) produced a resource of good quality but low quantity, and on the larger plot (3000m 2 ) a low stocking rate (LSR) created a sward of low quality but good quantity. We show that on initially homogeneous swards, sheep exhibited correlated random walks, reducing movement quantities to achieve their intake. After a few weeks of grazing, vegetation structure become more complex and sheep modulated their foraging paths through resource abundance and/or sward structure. We identified a breakpoint at 5m for which fractal dimension is always low. At lower scales (below 5m), the modulation of sinuosity was not linked to sward abundance and structure, and sheep adapted grazing behaviour at bite and feeding station scales. At higher scales (above 5m), modulation of grazing activity was achieved through path sinuosity in relation to perception of the environment. Grazing paths were tortuous on tall swards in summer, and straighter on heterogeneous, well-structured swards showing visual cues in autumn. Fractal dimension of grazing paths proved to be a synthetic measurement, which allowed identification of a hierarchical threshold in the spatial adaptation of foraging behaviour in domestic herbivores at grazing.
- Subjects :
- 0106 biological sciences
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences
Foraging
Sinuosity
010603 evolutionary biology
01 natural sciences
Grassland
Food Animals
Abundance (ecology)
Grazing
FORAGING PATH
ComputingMilieux_MISCELLANEOUS
GRAZING BEHAVIOUR
2. Zero hunger
Herbivore
geography
geography.geographical_feature_category
CORRELATED RANDOM WALK
0402 animal and dairy science
04 agricultural and veterinary sciences
Vegetation
15. Life on land
040201 dairy & animal science
Fractal analysis
Agronomy
Environmental science
Animal Science and Zoology
FRACTAL ANALYSIS
Subjects
Details
- Language :
- English
- ISSN :
- 01681591 and 18729045
- Database :
- OpenAIRE
- Journal :
- Applied Animal Behaviour Science, Applied Animal Behaviour Science, Elsevier, 2005, 93, pp.19-37
- Accession number :
- edsair.doi.dedup.....15417b2d0cd5accbf9e58c77c1e85d6d