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Is spatial autocorrelation an intrinsic property of territory size?

Valcu M, Kempenaers B - Oecologia (2010)

Bottom Line: In animals, competition for space and resources often results in territorial behaviour.We found significant positive SAC in a wide array of competition-simulated conditions.Our results strongly suggest that SAC is an intrinsic trait of any territory measure.

View Article: PubMed Central - PubMed

Affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Seewiesen, Germany. valcu@orn.mpg.de

ABSTRACT
In animals, competition for space and resources often results in territorial behaviour. The size of a territory is an important correlate of fitness and is primarily determined by the spatial distribution of resources and by interactions between competing individuals. Both of these determinants, alone or in interaction, could lead to spatial non-independence of territory size (i.e. spatial autocorrelation). We investigated the presence and magnitude of spatial autocorrelation (SAC) in territory size using Monte Carlo simulations of the most widely used territory measures. We found significant positive SAC in a wide array of competition-simulated conditions. A meta-analysis of territory size data showed that SAC is also a feature of territories mapped based on behavioural observations. Our results strongly suggest that SAC is an intrinsic trait of any territory measure. Hence, we recommend that appropriate statistical methods should be employed for the analysis of data sets where territory size is either a dependent or an explanatory variable.

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Type I error rate for α = 0.01 (indicated by the thinhorizontalline) of Pearson correlation coefficients for three classes of territory models as a function of the spatial autocorrelation coefficient ρ of a simultaneous autoregressive process (spatially autocorrelated covariate). For comparison IM is shown on the upper x-axis
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Fig3: Type I error rate for α = 0.01 (indicated by the thinhorizontalline) of Pearson correlation coefficients for three classes of territory models as a function of the spatial autocorrelation coefficient ρ of a simultaneous autoregressive process (spatially autocorrelated covariate). For comparison IM is shown on the upper x-axis

Mentions: As expected, the type I error rate increased with increasing autocorrelation of the covariate z′ for all three scenarios (Fig. 3). The error rate depends on the SAC in territory size: it is highest in the case of Thiessen territories under CSR (IM = 0.31), intermediate for Thiessen territories under SSI (IM = 0.22) and lowest under kernel territories (IM = 0.15; Fig. 3).Fig. 3


Is spatial autocorrelation an intrinsic property of territory size?

Valcu M, Kempenaers B - Oecologia (2010)

Type I error rate for α = 0.01 (indicated by the thinhorizontalline) of Pearson correlation coefficients for three classes of territory models as a function of the spatial autocorrelation coefficient ρ of a simultaneous autoregressive process (spatially autocorrelated covariate). For comparison IM is shown on the upper x-axis
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2821514&req=5

Fig3: Type I error rate for α = 0.01 (indicated by the thinhorizontalline) of Pearson correlation coefficients for three classes of territory models as a function of the spatial autocorrelation coefficient ρ of a simultaneous autoregressive process (spatially autocorrelated covariate). For comparison IM is shown on the upper x-axis
Mentions: As expected, the type I error rate increased with increasing autocorrelation of the covariate z′ for all three scenarios (Fig. 3). The error rate depends on the SAC in territory size: it is highest in the case of Thiessen territories under CSR (IM = 0.31), intermediate for Thiessen territories under SSI (IM = 0.22) and lowest under kernel territories (IM = 0.15; Fig. 3).Fig. 3

Bottom Line: In animals, competition for space and resources often results in territorial behaviour.We found significant positive SAC in a wide array of competition-simulated conditions.Our results strongly suggest that SAC is an intrinsic trait of any territory measure.

View Article: PubMed Central - PubMed

Affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Seewiesen, Germany. valcu@orn.mpg.de

ABSTRACT
In animals, competition for space and resources often results in territorial behaviour. The size of a territory is an important correlate of fitness and is primarily determined by the spatial distribution of resources and by interactions between competing individuals. Both of these determinants, alone or in interaction, could lead to spatial non-independence of territory size (i.e. spatial autocorrelation). We investigated the presence and magnitude of spatial autocorrelation (SAC) in territory size using Monte Carlo simulations of the most widely used territory measures. We found significant positive SAC in a wide array of competition-simulated conditions. A meta-analysis of territory size data showed that SAC is also a feature of territories mapped based on behavioural observations. Our results strongly suggest that SAC is an intrinsic trait of any territory measure. Hence, we recommend that appropriate statistical methods should be employed for the analysis of data sets where territory size is either a dependent or an explanatory variable.

Show MeSH