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Density-dependent and -independent effects on the joint use of space by predators and prey in terrestrial arthropod food-webs

Birkhofer, Klaus LU ; Wolters, Volkmar and Diekötter, Tim (2011) In Oikos 120(11). p.1705-1711
Abstract
The spatial distribution of predators and their prey is affected by their joint use of space. While the formation of such spatial patterns may be driven by density-dependent and -independent factors our knowledge on the contribution of different land-use activities on the formation of spatial patterns between predators and prey remains very limited. Agriculture is one of the most prevailing land-use activities with strong effects on invertebrate densities and structural habitat conditions. Here, we used replicated conventionally and organically managed winter wheat fields to investigate the effects of agricultural land-use on the spatial patterns of generalist predators and decomposer prey. We then identified the explanatory power of... (More)
The spatial distribution of predators and their prey is affected by their joint use of space. While the formation of such spatial patterns may be driven by density-dependent and -independent factors our knowledge on the contribution of different land-use activities on the formation of spatial patterns between predators and prey remains very limited. Agriculture is one of the most prevailing land-use activities with strong effects on invertebrate densities and structural habitat conditions. Here, we used replicated conventionally and organically managed winter wheat fields to investigate the effects of agricultural land-use on the spatial patterns of generalist predators and decomposer prey. We then identified the explanatory power of density-dependent (prey and predator activity density) and density-independent (vegetation structure) predictors for the observed spatial patterns. Generalist predators were regularly distributed only in conventionally managed fields and this pattern intensified with decreasing Collembola prey availability and increasing spider activity density. Segregation between carabid and spider predators was strongest in fields with lowest wheat plant height, suggesting more intense intraguild interactions in structurally less complex habitats. Collembola were aggregated independent of management and aggregation was strongest in fields with highest Collembola and carabid activity density. Spiders and Collembola prey were associated, but higher aphid densities under conventional management weakened or interrupted this spatial relationship. We conclude that active control of crop plant physiognomy by growth hormones and herbicides in conventionally managed fields promotes predator–predator segregation and that a high availability of aphid prey seems to decouple predator–Collembola prey associations. Our results emphasise the need for a more mechanistic understanding of the effects of land-use on the formation of spatial patterns and species interactions, especially under scenarios of environmental change and an ongoing loss of biodiversity. (Less)
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author
organization
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type
Contribution to journal
publication status
published
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in
Oikos
volume
120
issue
11
pages
1705 - 1711
publisher
Wiley-Blackwell
external identifiers
  • scopus:80055096725
ISSN
1600-0706
DOI
10.1111/j.1600-0706.2011.19546.x
language
English
LU publication?
yes
id
689a8cda-44ad-4ac0-a652-34ccbb114da6 (old id 2440377)
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http://www.scopus.com/inward/record.url?eid=2-s2.0-80055096725&partnerID=40&md5=5594a27e54d3f6c24c217bca4e089509
date added to LUP
2012-06-18 14:33:33
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2017-06-25 03:26:10
@article{689a8cda-44ad-4ac0-a652-34ccbb114da6,
  abstract     = {The spatial distribution of predators and their prey is affected by their joint use of space. While the formation of such spatial patterns may be driven by density-dependent and -independent factors our knowledge on the contribution of different land-use activities on the formation of spatial patterns between predators and prey remains very limited. Agriculture is one of the most prevailing land-use activities with strong effects on invertebrate densities and structural habitat conditions. Here, we used replicated conventionally and organically managed winter wheat fields to investigate the effects of agricultural land-use on the spatial patterns of generalist predators and decomposer prey. We then identified the explanatory power of density-dependent (prey and predator activity density) and density-independent (vegetation structure) predictors for the observed spatial patterns. Generalist predators were regularly distributed only in conventionally managed fields and this pattern intensified with decreasing Collembola prey availability and increasing spider activity density. Segregation between carabid and spider predators was strongest in fields with lowest wheat plant height, suggesting more intense intraguild interactions in structurally less complex habitats. Collembola were aggregated independent of management and aggregation was strongest in fields with highest Collembola and carabid activity density. Spiders and Collembola prey were associated, but higher aphid densities under conventional management weakened or interrupted this spatial relationship. We conclude that active control of crop plant physiognomy by growth hormones and herbicides in conventionally managed fields promotes predator–predator segregation and that a high availability of aphid prey seems to decouple predator–Collembola prey associations. Our results emphasise the need for a more mechanistic understanding of the effects of land-use on the formation of spatial patterns and species interactions, especially under scenarios of environmental change and an ongoing loss of biodiversity.},
  author       = {Birkhofer, Klaus and Wolters, Volkmar and Diekötter, Tim},
  issn         = {1600-0706},
  language     = {eng},
  number       = {11},
  pages        = {1705--1711},
  publisher    = {Wiley-Blackwell},
  series       = {Oikos},
  title        = {Density-dependent and -independent effects on the joint use of space by predators and prey in terrestrial arthropod food-webs},
  url          = {http://dx.doi.org/10.1111/j.1600-0706.2011.19546.x},
  volume       = {120},
  year         = {2011},
}