The impacts of spatial and temporal complexity across landscapes on biological control: a review

Cohen, Abigail; Crowder, David W.

doi:10.1016/j.cois.2017.02.004

Cited by 26 publications

(16 citation statements)

References 40 publications

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“…The minimum proportion of semi‐natural habitat was 20% and the maximum proportion of cultivated land was 70%. According to Cohen and Crowder (), a landscape can be considered simplified when there is less than 20% semi‐natural habitat, and complex when there is more than 20% semi‐natural habitat.…”

Section: Discussionmentioning

confidence: 99%

“…Land use around the focal fields was first quantified by remote sensing digital images from the data centre of the Chinese Academy of Sciences using ArcGIS 10.0, within a radius of 2,000 m, and then ground truthed in July 2014, resulting in land‐use data with a resolution of 2.5 m. A total of 45 land‐use types were distinguished and for the analysis pooled into ten categories: early rice, middle rice, horticulture, other arable land, forest, grassland, hedgerows, water, built‐up and unused land (Appendix ). These land‐use categories take into account that different types of crop and non‐crop habitat can differ in their effects on pests and natural enemies (Cohen & Crowder, ), and also account for the temporal dynamics of potential source habitats of rice pests (Schellhorn, Gagic, & Bommarco, ).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Do diverse landscapes provide for effective natural pest control in subtropical rice?

Zou

Kraker

Bianchi

et al. 2019

Journal of Applied Ecology

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1. While the biocontrol potential of natural enemies is well established, it is largely unknown how landscape-mediated effects on pest and natural enemy communities impact the cascade of biocontrol potential, crop injury, yield and profit, taking into account crop management and surrounding landscape composition.2. We compared natural biocontrol with chemical control according to local farmers' practice, across the 'full cascade' from natural enemy and pest abundance to crop injury, yield loss, yield and economic performance. This 2-year study was conducted in 20 rice fields embedded in a gradient of landscapes from crop-dominated to semi-natural habitat-dominated, in subtropical China, the world's largest rice-producing region.3. Natural enemies suppressed brown planthopper population growth in unsprayed plots, irrespective of landscape composition. However, crop injury was lower in pesticide treated plots than in unsprayed plots, and yields in sprayed plots were 20% higher than in unsprayed plots. Nevertheless, pesticide applications were only profitable in less than half of the cases when only costs for pesticides were considered, and in less than one third of the cases when costs for pesticides and labour were considered. Synthesis and applications.Our findings question the cost-effectiveness of current chemical-based pest management in farming, and highlight opportunities for more ecologically based pest management strategies based on the widespread activity of natural enemies. Pest damage and biocontrol, however, are largely independent from the landscape context, which might be due to the small-scale character of Chinese rice landscapes. To maintain high levels of biocontrol, conserving this small-scale character appears more important than increasing the proportion of semi-natural habitat.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Do diverse landscapes provide for effective natural pest control in subtropical rice?

Zou

Kraker

Bianchi

et al. 2019

Journal of Applied Ecology

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“…Non-crop habitat is not the only landscape feature that may promote desirable pest and enemy dynamics in agricultural landscapes. The heterogeneity of farmland itself is increasingly recognized for its relevance to biodiversity conservation (Perfecto et al, 2019;Sirami et al, 2019) and ecosystem service provisioning (Vasseur et al, 2013;Cohen and Crowder, 2017;Redlich et al, 2018). In particular, crop diversity at the landscape scale could offer temporally complementary resource patches to mobile generalists that can make use of different habitats throughout the growing season, as well as "bridge" seminatural habitat and annual cropland by providing connectivity in time and space.…”

Section: Landscape Featuresmentioning

confidence: 99%

Temporal Resource (Dis)continuity for Conservation Biological Control: From Field to Landscape Scales

Iuliano

Gratton

2020

Front. Sustain. Food Syst.

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Conservation biological control (CBC) seeks to promote the occurrence of natural enemies of agricultural pests by managing habitat to provide key resources in and around farm fields. In particular, vegetation diversity may help ensure temporal resource continuity such that natural enemies are less likely to experience detrimental gaps or bottlenecks as they move through and use different habitats. While the conceptual value of resource continuity has long been recognized by CBC researchers and practitioners, empirical studies have tended to focus on snapshots in space and time. Here we review how continuity of trophic (food) and structural (shelter) resources affect natural enemy conservation and pest control outcomes within farm fields and across agricultural landscapes. Key trophic resources include alternative prey and non-prey food (such as floral nectar and pollen), which can bolster natural enemy nutrition when pests are scarce. Vegetative and non-vegetative structural resources can protect enemies when crop fields are disturbed and provide important overwintering habitat in temperate regions. Within fields, non-crop plantings such as wildflower strips or beetle banks are the most popular habitat management strategies, but temporal intercropping, asynchronous planting/harvesting, and the construction of artificial shelters have high potential to contribute to resource continuity. Analogously, semi-natural habitat at the landscape scale may contribute to resource continuity in some cases, but crop diversity, asynchrony, and urban habitat can also be important. Simultaneous consideration of resource diversity and continuity could generate better predictions and more targeted management interventions for particular pest and enemy assemblages. Future research should strive to expand our understanding of natural enemy resource requirements in space and time.

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“…For example, increasing non-crop habitat surrounding agricultural fields can promote insect abundance, diversity, pollination, and natural pest control (Dainese et al 2019, Kennedy et al 2013, Chaplin-Kramer et al 2011, Ricketts et al 2009, but see Karp et al 2018). Yet a facile understanding of habitat vs. non-habitat or cropland vs. natural area ignores the substantial heterogeneity that exists within land use categories (Vasseur et al 2013) as well as the complex temporal dynamics of mobile consumers and their resources across the landscape (Cohen & Crowder 2017, Schellhorn et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Temporal resource continuity increases predator abundance in a metapopulation model: insights for conservation and biocontrol

Spiesman

Iuliano

Gratton

2020

Preprint

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The amount of habitat in a landscape is an important metric for evaluating the effects of land cover and land use on biodiversity and ecosystem services, yet it fails to capture complex temporal dimensions of resource availability that could be consequential for species population dynamics. If ephemeral resources across multiple habitat patches are synchronously available, resource gaps could be detrimental to population growth. In contrast, asynchronously available resources create a mosaic of temporally complementary resources that mobile organisms can track across the landscape. Knowledge is especially lacking on the relevance of temporal complementation for tri-trophic interactions and biological pest control. Here we use a spatially-explicit predator-prey metapopulation model to test the effect of different spatiotemporal resource patterns on insect predators and their prey. We examined prey and predator responses in model landscapes that varied in both the amount and temporal variability of basal vegetation resources. Further, we examined cases where prey comprised either a single generalist species or two specialist species that use different resources available either early or late in the growing season. We found that predators and generalist prey benefitted from lower temporal variance of basal resources, which increased both of their landscape-scale abundances.However, increasing the amount of basal resources also increased the variability of generalist prey populations, resulting in a negative correlation between basal resource amount and predator abundance. Specialist prey, on the other hand, did not benefit from less temporally variable in basal resources, since they were restricted by habitat type while also suffering greater predation.Predators feeding on specialists achieved greater prey suppression in landscapes with less temporally variable resources. Our simulations demonstrate the joint importance of Spiesman et al. 3 landscape-scale temporal dynamics of resources and resource amount in understanding how landscape heterogeneity influences biodiversity and ecosystem services such as the biological control of agricultural pests.

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The impacts of spatial and temporal complexity across landscapes on biological control: a review

Cited by 26 publications

References 40 publications

Do diverse landscapes provide for effective natural pest control in subtropical rice?

Do diverse landscapes provide for effective natural pest control in subtropical rice?

Temporal Resource (Dis)continuity for Conservation Biological Control: From Field to Landscape Scales

Temporal resource continuity increases predator abundance in a metapopulation model: insights for conservation and biocontrol

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