Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

Macfadyen, Sarina; Gibson, Rachel; Polaszek, Andrew; Morris, Rebecca J.; Craze, Paul G.; Planquè, Robert; Symondson, William Oliver Christian; Memmott, Jane

doi:10.1111/j.1461-0248.2008.01279.x

Cited by 195 publications

(156 citation statements)

References 47 publications

(109 reference statements)

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“…This difference was found across countries, farm types (grassland versus arable), and crop and soil type. This finding is in agreement with Doles et al (2001) and Macfadyen et al (2009).…”

Section: Microarthropod Diversitysupporting

confidence: 82%

An ecosystem approach to assess soil quality in organically and conventionally managed farms in Iceland and Austria

Leeuwen¹,

Sandén²,

Lair³

et al. 2015

SOIL

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Abstract. Intensive agricultural production can be an important driver for the loss of long-term soil quality. For this reason, the European Critical Zone Observatory (CZO) network adopted four pairs of agricultural CZO sites that differ in their management: conventional or organic. The CZO sites include two pairs of grassland farms in Iceland and two pairs of arable farms in Austria. Conventional fields differed from the organic fields in the use of artificial fertilisers and pesticides. Soils of these eight farms were analysed in terms of their physical, chemical, and biological properties, including soil aggregate size distribution, soil organic matter contents, abundance of soil microbes and soil fauna, and taxonomic diversity of soil microarthropods. In Icelandic grasslands, organically farmed soils had larger mean weight diameters of soil aggregates than the conventional farms, while there were no differences on the Austrian farms. Organic farming did not systematically influence organic matter contents or composition, nor soil carbon and nitrogen contents. Also, soil food web structures, in terms of presence of trophic groups of soil organisms, were highly similar among all farms, indicating a low sensitivity of trophic structure to land use or climate. However, soil organism biomass, especially of bacteria and nematodes, was consistently higher on organic farms than on conventional farms. Within the microarthropods, taxonomic diversity was systematically higher in the organic farms compared to the conventional farms. This difference was found across countries and farm, crop, and soil types. The results do not show systematic differences in physical and chemical properties between organic and conventional farms, but confirm that organic farming can enhance soil biomass and that microarthropod diversity is a sensitive and consistent indicator for land management.

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“…This difference was found across countries, farm types (grassland versus arable), and crop and soil type. This finding is in agreement with Doles et al (2001) and Macfadyen et al (2009).…”

Section: Microarthropod Diversitysupporting

confidence: 82%

An ecosystem approach to assess soil quality in organically and conventionally managed farms in Iceland and Austria

Leeuwen¹,

Sandén²,

Lair³

et al. 2015

SOIL

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“…We have shown in a previous study that organic farms with greater parasitoid species richness do not show greater provision of pest control services [8]. Here, we ask whether increased parasitoid species richness provides greater temporal stability in parasitism rates and whether organic farms are more resilient to species loss.…”

Section: Introductionmentioning

confidence: 99%

“…The first prediction we make from our data is that there will be a strong relationship between parasitoid species richness and variability in parasitism rate across time. We predict that the organic farms, which show greater parasitoid diversity [8], will also show greater temporal stability in parasitism rates. Our second prediction is that organic farms have greater levels of functional redundancy (numbers of parasitoid species within functional groups) and this will lead to more reliable pest control services under environmental change.…”

Section: Introductionmentioning

confidence: 99%

Parasitoid diversity reduces the variability in pest control services across time on farms

et al. 2011

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Recent declines in biodiversity have increased interest in the link between biodiversity and the provision and sustainability of ecosystem services across space and time. We mapped the complex network of interactions between herbivores and parasitoids to examine the relationship between parasitoid species richness, functional group diversity and the provision of natural pest control services. Quantitative food webs were constructed for 10 organic and 10 conventional farms. Parasitoid species richness varied from 26 to 58 species and we found a significant positive relationship between parasitoid species richness and temporal stability in parasitism rates. Higher species richness was associated with lower variation in parasitism rate. A functional group analysis showed significantly greater parasitoid species complementarity on organic farms, with on average more species in each functional group. We simulated parasitoid removal to predict whether organic farms experienced greater robustness of parasitism in the face of local extinctions. This analysis showed no consistent differences between the organic and conventional farm pairs in terms of loss of pest control service. Finally, it was found that the different habitats that make up each farm do not contribute equally to parasitoid species diversity, and that hedgerows produced more parasitoid species, significantly more so on organic farms.

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“…For example, organic agriculture has been shown to sustain higher levels of insect trophic complexity, and species evenness than conventional agriculture [125,126], and organic perennial systems can maintain stable pest levels over the long term [127]. However, landscape and management characteristics such as fallow management and planting date appear to be more important for the function of arthropod food webs in some cases than the use of pesticides themselves [128].…”

Section: Management Implicationsmentioning

confidence: 99%

5 Key Challenges and Solutions for Governing Complex Adaptive (Food) Systems

et al. 2017

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Abstract:There is increasing recognition in academic circles of the importance of adaptive governance for the sustainability of social-ecological systems, but little examination of specific implications for the 34% of land-use where human activities are pervasive but potentially commensurate with functioning ecosystems: agricultural production systems. In this paper, we argue for the need to view food systems and agro-ecosystems as multi-scalar complex adaptive systems and identify five key challenging characteristics of such systems: multi-causality; cumulative impacts; regime shifts; teleconnections and mismatch of scales. These characteristics are necessary features of multi-scalar adaptive systems, and apply equally to social and natural subsystems. We discuss the implications of these characteristics for agricultural production systems and consider how governance can rise to these challenges. We present five case studies that highlight these issues: pollinator declines; payments for ecosystem services; pest control and pesticide resistance; downstream aquatic systems in Tasman Bay, New Zealand; and riparian buffers in Puget Sound, USA. From these case studies we derive recommendations for managing agricultural systems, both specific and general. Ultimately, adaptive governance of agro-ecosystems will likely hinge upon three paradigm shifts: viewing farmers and ranchers not only as food producers but also as land and water managers; seeking not yield maximization but rather resilient management of food ecosystems; and critically, as it transcends the production-system literature, engaging broad audiences not only as consumers but also citizens.

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Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

Cited by 195 publications

References 47 publications

An ecosystem approach to assess soil quality in organically and conventionally managed farms in Iceland and Austria

An ecosystem approach to assess soil quality in organically and conventionally managed farms in Iceland and Austria

Parasitoid diversity reduces the variability in pest control services across time on farms

5 Key Challenges and Solutions for Governing Complex Adaptive (Food) Systems

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