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The effect on dispersal from complex correlations in small-scale movement

Westerberg, Lars; Lindstrom, Tom; Nilsson, Elna LU and Wennergren, Uno (2008) In Ecological Modelling 213(2). p.263-272
Abstract
Calculations of large-scale displacement distances were made to evaluate the combined effect of small-scale movement pattern of a Collembola, Protaphorura armata. The effect of presence of food and conspecific density on turning angle, step length and activity/motility was investigated. Calculations of net square displacement were made both by assuming correlated random walk (CRW) and by resampling data to account for correlation structures in movement patterns that violate the assumptions of CRW. In presence of food, individuals spent less time moving (decreased activity), but when they moved they showed larger turning angles than individuals moving in areas without food. Increased conspecific density did not affect time spent moving by... (More)
Calculations of large-scale displacement distances were made to evaluate the combined effect of small-scale movement pattern of a Collembola, Protaphorura armata. The effect of presence of food and conspecific density on turning angle, step length and activity/motility was investigated. Calculations of net square displacement were made both by assuming correlated random walk (CRW) and by resampling data to account for correlation structures in movement patterns that violate the assumptions of CRW. In presence of food, individuals spent less time moving (decreased activity), but when they moved they showed larger turning angles than individuals moving in areas without food. Increased conspecific density did not affect time spent moving by individuals, but when step length decreased and turning angle increased. P. armata showed negative density-dependent dispersal and exhibited area-restricted search as a response to both food and increased conspecific density. The CRW was relatively robust to some violations of its underlying assumptions. However, the expected displacement increased substantially, as much as 50%, when accounting for observed auto-correlation in step length and correlation between step length and turning angle. Hence, an explanation for increased displacement and dispersal of a species can also be the result of a more complex correlation of its behaviour rather than solely altering specific movement parameters, for example increasing step length or decreasing turning angle. The results emphasise the importance of careful analysis of small-scale movement before using them as predictors of population distribution and invasion speed in heterogeneous landscapes. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
net square displacement, protaphorura armata, correlated random walk
in
Ecological Modelling
volume
213
issue
2
pages
263 - 272
publisher
Elsevier
external identifiers
  • wos:000255453600011
  • scopus:40849135933
ISSN
0304-3800
DOI
10.1016/j.ecolmodel.2007.12.011
language
English
LU publication?
yes
id
bbbe651e-6227-4003-8ee8-337ea7420067 (old id 1205308)
date added to LUP
2008-09-18 14:11:48
date last changed
2017-01-01 06:06:01
@article{bbbe651e-6227-4003-8ee8-337ea7420067,
  abstract     = {Calculations of large-scale displacement distances were made to evaluate the combined effect of small-scale movement pattern of a Collembola, Protaphorura armata. The effect of presence of food and conspecific density on turning angle, step length and activity/motility was investigated. Calculations of net square displacement were made both by assuming correlated random walk (CRW) and by resampling data to account for correlation structures in movement patterns that violate the assumptions of CRW. In presence of food, individuals spent less time moving (decreased activity), but when they moved they showed larger turning angles than individuals moving in areas without food. Increased conspecific density did not affect time spent moving by individuals, but when step length decreased and turning angle increased. P. armata showed negative density-dependent dispersal and exhibited area-restricted search as a response to both food and increased conspecific density. The CRW was relatively robust to some violations of its underlying assumptions. However, the expected displacement increased substantially, as much as 50%, when accounting for observed auto-correlation in step length and correlation between step length and turning angle. Hence, an explanation for increased displacement and dispersal of a species can also be the result of a more complex correlation of its behaviour rather than solely altering specific movement parameters, for example increasing step length or decreasing turning angle. The results emphasise the importance of careful analysis of small-scale movement before using them as predictors of population distribution and invasion speed in heterogeneous landscapes.},
  author       = {Westerberg, Lars and Lindstrom, Tom and Nilsson, Elna and Wennergren, Uno},
  issn         = {0304-3800},
  keyword      = {net square displacement,protaphorura armata,correlated random walk},
  language     = {eng},
  number       = {2},
  pages        = {263--272},
  publisher    = {Elsevier},
  series       = {Ecological Modelling},
  title        = {The effect on dispersal from complex correlations in small-scale movement},
  url          = {http://dx.doi.org/10.1016/j.ecolmodel.2007.12.011},
  volume       = {213},
  year         = {2008},
}