Theoretical Ecology

, Volume 11, Issue 3, pp 321–331 | Cite as

Aggregating fields of annual crops to form larger-scale monocultures can suppress dispersal-limited herbivores

  • Collin B. Edwards
  • Jay A. Rosenheim
  • Moran Segoli


An important part of landscape ecology is determining how the arrangement (aggregation or fragmentation) of patches in space influences the population dynamics of foraging organisms. One hypothesis in agricultural ecology is that fine-grain spatial heterogeneity in cropping (many small agricultural fields) should provide better pest control than coarse-grain heterogeneity (few large agricultural fields); this hypothesis has been proposed as an explanation for the increased pest abundance associated with agricultural intensification. However, empirical studies have found mixed support for this hypothesis, and some, surprisingly, demonstrate a strong decrease in pest abundance with increased crop aggregation. We developed a spatially explicit simulation model of pest movement across an agricultural landscape to uncover basic processes that could reduce pest abundance in landscapes with fewer, larger fields. This model focuses on herbivore movement and does not include predation effects or other biological interactions. We found that field aggregation in the model led to severely reduced pest densities and further discovered that this relationship was due to an increased distance between fields and a decreased “target area” in more aggregated landscapes. The features that create a negative relationship between aggregation and pest densities rely on crop rotation and limited dispersal capabilities of the pests. These findings help to explain seemingly counter-intuitive empirical studies and provide an expectation for when field aggregation may reduce pest populations in agro-ecosystems.


Agroecology Simulation model Dispersal Land use Habitat fragmentation Agricultural intensification 



We thank Soroush Parsa for guidance on the biology of the potato weevil system and Stephen Ellner, Anurag Agrawal, and their respective labs for comments on the manuscript. Two anonymous reviewers provided comments that greatly improved this manuscript.

Funding information

This study was supported by a grant from the US Department of Agriculture (RAMP grant ARZT-358320-G-30-505) and a National Science Foundation Graduate Research Fellowship Program (NSF GRFP grant DGE-1144153) to C.B.E.

Supplementary material

12080_2018_369_MOESM10_ESM.txt (3 kb)
ESM 1 (TXT 2 kb)
12080_2018_369_MOESM1_ESM.docx (13 kb)
ESM 2 (DOCX 13 kb)
12080_2018_369_MOESM2_ESM.docx (12 kb)
ESM 3 (DOCX 12 kb)
12080_2018_369_MOESM3_ESM.eps (4 kb)
ESM 4 (EPS 4 kb)
12080_2018_369_MOESM4_ESM.txt (6 kb)
ESM 5 (TXT 5 kb)
12080_2018_369_MOESM5_ESM.txt (10 kb)
ESM 6 (TXT 10 kb)
12080_2018_369_MOESM6_ESM.txt (12 kb)
ESM 7 (TXT 11 kb)
12080_2018_369_MOESM7_ESM.txt (2 kb)
ESM 8 (TXT 1 kb)
12080_2018_369_MOESM8_ESM.txt (17 kb)
ESM 9 (TXT 16 kb)
12080_2018_369_MOESM9_ESM.txt (2 kb)
ESM 10 (TXT 2 kb)


  1. Altieri MA (2002) Agroecology: the science of natural resource management for poor farmers in marginal environments. Agric Ecosyst Environ 93:1–24. CrossRefGoogle Scholar
  2. Altieri MA, Letourneau DK (1982) Vegetation management and biological control in agroecosystems. Crop Prot 1(4):405–430. CrossRefGoogle Scholar
  3. Bender DJ, Contreras TA, Fahrig L (1998) Habitat loss and population decline: a meta-analysis of the patch size effect. Ecology 79:517–533. CrossRefGoogle Scholar
  4. Bianchi FJJA, Booij CJH, Tscharntke T (2006) Sustainable pest regulation in agricultural landscapes: a review on landscape composition, biodiversity and natural pest control. Proc Biol Sci 273:1715–1727. CrossRefPubMedPubMedCentralGoogle Scholar
  5. Bommarco R, Banks JE (2003) Scale as modifier in vegetation diversity experiments: effects on herbivores and predators. Oikos 102:440–448. CrossRefGoogle Scholar
  6. Bowers MA, Matter SF (1997) Landscape ecology of mammals: relationships between density and patch size. J Mammal 78:999–1013. CrossRefGoogle Scholar
  7. Bowman J, Cappuccino N, Fahrig L (2002) Patch size and population density: the effect of immigration behavior. Conserv Ecol 6(1):9. CrossRefGoogle Scholar
  8. Chavez A (1997) Actividad Migratoria y Daño del Gorgojo (Premnotrypes spp.) en dos Comunidades del Departamento de La Paz. [B.S.]. Universidad Tecnica de Oruro, OruroGoogle Scholar
  9. Debinski DM, Holt RD (2000) A survey and overview of habitat fragmentation experiments. Conserv Biol 14:342–355. CrossRefGoogle Scholar
  10. Englund G, Hambäck PA (2007) Scale dependence of immigration rates: models, metrics and data. J Anim Ecol 76:30–35. CrossRefPubMedGoogle Scholar
  11. Hambäck PA, Englund G (2005) Patch area, population density and the scaling of migration rates: the resource concentration hypothesis revisited. Ecol Lett 8:1057–1065. CrossRefGoogle Scholar
  12. Ioannou CC, Bartumeus F, Krause J, Ruxton GD (2011) Unified effects of aggregation reveal larger prey groups take longer to find. Proc R Soc B 278:2985–2990. CrossRefPubMedGoogle Scholar
  13. Kaya H, Alcazar J, Parsa S, Kroschel J (2009) Microbial control of the Andean potato weevil complex. Fruit Veg Cereal Sci Biotech 3(1):39–45. CrossRefGoogle Scholar
  14. Parsa S (2010) Native herbivore becomes a key pest after dismantlement of a traditional farming system. Am Entomol 56(4):242–251. CrossRefGoogle Scholar
  15. Parsa S, Ccanto R, Rosenheim JA (2011) Resource concentration dilutes a key pest in indigenous potato agriculture. Ecol Appl 21:539–546. CrossRefPubMedGoogle Scholar
  16. Poveda K, Gomez MI, Martinez E (2008) Diversification practices: their effect on pest regulation and production. Rev Colomb Entomolgia 34:131–144Google Scholar
  17. Root RB (1973) Organization of a plant-arthropod association in simple and diverse habitats: the fauna of collards (Brassica oleracea). Ecol Monogr 43:95–124. CrossRefGoogle Scholar
  18. Segoli M, Rosenheim JA (2012) Should increasing the field size of monocultural crops be expected to exacerbate pest damage? Agric Ecosyst Environ 150:38–44. CrossRefGoogle Scholar
  19. Vinatier F, Lescourret F, Duyck PF, Tixier F (2012) From IBM to IPM: using individual-based models to design the spatial arrangement of traps and crops in integrated pest management strategies. Agric Ecosyst Environ 146(1):52–59. CrossRefGoogle Scholar
  20. White JW, Rassweiler A, Samhouri JF, Stier AC, White C (2014) Ecologists should not use statistical significance tests to interpret simulation model results. Oikos 123:385–388. CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Evolution and EcologyUniversity of California-DavisDavisUSA
  2. 2.Department of Ecology and Evolutionary BiologyIthacaUnited States
  3. 3.Department of Entomology and NematologyUniversity of California-DavisDavisUSA
  4. 4.Desert Agro-Research Centers—Ramat Ha-Negev and BesorMP HaluzaIsrael

Personalised recommendations