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Data for: Remote sensing reveals the importance of adjacent seminatural habitat and irrigation method on aphid biocontrol in arid agroecosystems

Call, Anson1; Akiba, Sami1; Pringle, Elizabeth1

Research facility: University of Nevada Reno
Published Aug 16, 2024 on Dryad. https://doi.org/10.5061/dryad.np5hqc00r

Data files

Abstract

Remote sensing and nuanced spatial analyses are increasingly used to understand the role of seminatural habitats in biocontrol, but knowing how to best leverage these tools is a persistent challenge. Furthermore, these tools are seldom applied to arid and semiarid agroecosystems, where irrigation often exaggerates the differences between crop fields and their interspaces. In arid systems, small weedy areas adjacent to watered fields are often one of the only sources of persistent vegetation; remote sensing and careful spatial analysis may be essential to capture the effect of this fine-scale variation on pest biocontrol.

Using irrigated alfalfa farms in the Great Basin Desert (Nevada, USA), we examined the role of land-cover in determining the degree of aphid pest pressure and biocontrol within alfalfa fields. We used a combination of field surveys, remote sensing, and spatial analysis to permit comparisons between different methods of assessing land-cover and the importance of spatial scale. Additionally, we experimentally manipulated predator densities to assess the combined direct and indirect effects of seminatural habitat on aphid biocontrol.

Although the influence of land-cover types varied between seasons and among arthropod taxa, our results indicate that our predictions were supported in a few cases—notably for coccinellid beetles, a key aphid predator in this system.

Our remote-sensing approach was more effective than conventional vegetation surveys in revealing the importance of spatial scale, the effect of flood irrigation, and the role of weedy patches within alfalfa fields.

Synthesis and applications. Weedy seminatural habitat near alfalfa fields, such as naturally occurring weedy areas along field margins and the banks of irrigation ditches, was positively associated with the density of a key aphid predator. Preserving these weedy areas can enhance aphid biocontrol, but farmers must consider potential tradeoffs between pest control and weed control.