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Landscape-scale interactions of spatial and temporal cropland heterogeneity drive biological control of cereal aphids

Bosem Baillod, Aliette; Tscharntke, Teja; Clough, Yann LU and Batáry, Péter (2017) In Journal of Applied Ecology
Abstract

Agricultural landscapes are characterised by dynamic crop mosaics changing in composition and configuration over space and time. Although semi-natural habitat has been often shown to contribute to pest biological control, the effects of increasing landscape heterogeneity with cropland have been disregarded. Here, we examine how cereal aphids, their enemies and biological control are affected by the composition and configuration of the crop mosaic and its inter-annual change due to crop rotation. We studied the abundance of cereal aphids, natural enemies and aphid parasitism over 2 years on 51 winter wheat fields. Arthropods were monitored at three distances (0, 10, 30 m) from field borders. Fields were embedded in landscapes of 1-km... (More)

Agricultural landscapes are characterised by dynamic crop mosaics changing in composition and configuration over space and time. Although semi-natural habitat has been often shown to contribute to pest biological control, the effects of increasing landscape heterogeneity with cropland have been disregarded. Here, we examine how cereal aphids, their enemies and biological control are affected by the composition and configuration of the crop mosaic and its inter-annual change due to crop rotation. We studied the abundance of cereal aphids, natural enemies and aphid parasitism over 2 years on 51 winter wheat fields. Arthropods were monitored at three distances (0, 10, 30 m) from field borders. Fields were embedded in landscapes of 1-km diameter selected along orthogonal gradients of compositional crop heterogeneity (crop diversity), configurational heterogeneity (field border and grassy field boundary length) and inter-annual change in cover of aphid host habitats (cereal, maize and grassland). We aimed to disentangle spatial and temporal heterogeneity effects through these independent landscape gradients. Aphid densities were lower in landscapes with smaller field size (more field borders) coupled with high amounts of grassy field boundaries. Aphid densities decreased also in landscapes with higher crop diversity when the cover of aphid host habitat had decreased from the year before. Aphid natural enemy densities decreased with smaller field size and high amounts of grassy field boundaries. Aphid parasitism decreased with the inter-annual expansion in aphid host habitat, but only in landscapes with small field sizes. Synthesis and applications. Our study shows for the first time that cereal aphid numbers can be reduced by optimising the composition, configuration and temporal heterogeneity of the crop mosaic. We highlight the value of maintaining small field sizes in agricultural landscapes and high densities of grassy boundaries for reducing aphid abundance. Landscape-wide crop diversification can reduce aphid densities as well.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Aphid parasitism, Crop rotation, Edge effect, Field margin, Field size, Landscape composition, Landscape configuration, Predator-prey ratio, Spatial heterogeneity, Temporal heterogeneity
in
Journal of Applied Ecology
publisher
Wiley-Blackwell
external identifiers
  • scopus:85018740493
ISSN
0021-8901
DOI
10.1111/1365-2664.12910
language
English
LU publication?
yes
id
f039c07a-ef15-4123-9ab6-14ae9c615785
date added to LUP
2017-05-24 13:16:52
date last changed
2017-05-24 13:16:52
@article{f039c07a-ef15-4123-9ab6-14ae9c615785,
  abstract     = {<p>Agricultural landscapes are characterised by dynamic crop mosaics changing in composition and configuration over space and time. Although semi-natural habitat has been often shown to contribute to pest biological control, the effects of increasing landscape heterogeneity with cropland have been disregarded. Here, we examine how cereal aphids, their enemies and biological control are affected by the composition and configuration of the crop mosaic and its inter-annual change due to crop rotation. We studied the abundance of cereal aphids, natural enemies and aphid parasitism over 2 years on 51 winter wheat fields. Arthropods were monitored at three distances (0, 10, 30 m) from field borders. Fields were embedded in landscapes of 1-km diameter selected along orthogonal gradients of compositional crop heterogeneity (crop diversity), configurational heterogeneity (field border and grassy field boundary length) and inter-annual change in cover of aphid host habitats (cereal, maize and grassland). We aimed to disentangle spatial and temporal heterogeneity effects through these independent landscape gradients. Aphid densities were lower in landscapes with smaller field size (more field borders) coupled with high amounts of grassy field boundaries. Aphid densities decreased also in landscapes with higher crop diversity when the cover of aphid host habitat had decreased from the year before. Aphid natural enemy densities decreased with smaller field size and high amounts of grassy field boundaries. Aphid parasitism decreased with the inter-annual expansion in aphid host habitat, but only in landscapes with small field sizes. Synthesis and applications. Our study shows for the first time that cereal aphid numbers can be reduced by optimising the composition, configuration and temporal heterogeneity of the crop mosaic. We highlight the value of maintaining small field sizes in agricultural landscapes and high densities of grassy boundaries for reducing aphid abundance. Landscape-wide crop diversification can reduce aphid densities as well.</p>},
  author       = {Bosem Baillod, Aliette and Tscharntke, Teja and Clough, Yann and Batáry, Péter},
  issn         = {0021-8901},
  keyword      = {Aphid parasitism,Crop rotation,Edge effect,Field margin,Field size,Landscape composition,Landscape configuration,Predator-prey ratio,Spatial heterogeneity,Temporal heterogeneity},
  language     = {eng},
  month        = {05},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of Applied Ecology},
  title        = {Landscape-scale interactions of spatial and temporal cropland heterogeneity drive biological control of cereal aphids},
  url          = {http://dx.doi.org/10.1111/1365-2664.12910},
  year         = {2017},
}