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

@article{Macfadyen2009DoDI,
  title={Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?},
  author={Sarina Macfadyen and Rachel H. Gibson and Andrew Polaszek and Rebecca J. Morris and Paul G. Craze and Robert Planqu{\'e} and William O. C. Symondson and Jane Memmott},
  journal={Ecology letters},
  year={2009},
  volume={12 3},
  pages={
          229-38
        }
}
While many studies have demonstrated that organic farms support greater levels of biodiversity, it is not known whether this translates into better provision of ecosystem services. Here we use a food-web approach to analyse the community structure and function at the whole-farm scale. Quantitative food webs from 10 replicate pairs of organic and conventional farms showed that organic farms have significantly more species at three trophic levels (plant, herbivore and parasitoid) and… 

Figures and Tables from this paper

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

The complex network of interactions between herbivores and parasitoids is mapped to examine the relationship between parasitoid species richness, functional group diversity and the provision of natural pest control services and it was found that the different habitats that make up each farm do not contribute equally to parasitoidal species diversity.

Arthropod food webs in organic and conventional wheat farming systems of an agricultural long‐term experiment: a stable isotope approach

The results obtained suggest that generalist predators consumed higher proportions of herbivore prey in the organic system and that starvation and intraguild predation rates increased in some predator species with time.

High temporal consistency in quantitative food web structure in the face of extreme species turnover

The patterns uncovered suggest that quantitative, emergent characteristics of food web structure will exhibit less temporal variation than patterns at the level of individual food web parts, as these features reflect different, complementary aspects of how food webs are built and how communities are likely to function.

Landscape structure influences modularity patterns in farm food webs: consequences for pest control

If modules form as a result of interactions between species that utilize similar habitats, then ecosystem services to the crop components of the landscape, such as pest control by parasitoids originating in the non‐crop vegetation, are less likely to occur on these farms.

Farming practices change food web structures in cereal aphid–parasitoid–hyperparasitoid communities

In conclusion, agricultural intensification appears to foster the complexity of aphid–parasitoid food webs, thereby not supporting the general expectation on the importance of organic farming practices for species richness and food web complexity.

A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes

Both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations.

Plant diversity promotes species richness and community stability of arthropods in organic farming

Trophic cascades among plants, herbivores, and natural enemies can be affected by agriculture planting shifts from complex (polyculture) to simple (intensive). Yet, the information on regulation of
...

References

SHOWING 1-10 OF 47 REFERENCES

Habitat modification alters the structure of tropical host–parasitoid food webs

Altered interaction structure represents an insidious and functionally important hidden effect of habitat modification by humans, indicating that perturbation of the structure and function of ecological communities might be overlooked in studies that do not document and quantify species interactions.

On the Trophic Relations of Insects: A Food-Web Approach

Trophic relations of 95 insect-dominated food webs from seven habitat categories are examined and discussed in relation to current ecological theory, and nearly half of all the insect taxa (families) have members that are top predators in certain habitats even after vertebrates are factored in.

Network structure and biodiversity loss in food webs: robustness increases with connectance

Food-web structure mediates dramatic effects of biodiversity loss including secondary and ‘cascading’ extinctions and robustness increases with food-web connectance but appears independent of species richness and omnivory.

The effects of organic agriculture on biodiversity and abundance: a meta‐analysis

It is suggested that positive effects of organic farming on species richness can be expected in intensively managed agricultural landscapes, but not in small-scale landscapes comprising many other biotopes as well as agricultural fields.

Plant diversity and land use under organic and conventional agriculture: a whole‐farm approach

Summary 1 Organic farming is thought to lead to increased biodiversity and greater sustainability than higher-yielding conventional farming systems. It is usually assumed that organic farms

IMPACTS ON STREAM FOOD WEBS OF NATIVE AND EXOTIC FOREST: AN INTERCONTINENTAL COMPARISON

Native pine-forest streams from Maine and North Carolina, USA, and exotic pine-forest streams from New Zealand were compared to assess the effects of geographic location on three aspects of community

Structure of a diverse tropical forest insect–parasitoid community

Both the summary web and the seasonal webs show low levels of compartmentalization, suggesting that the host–parasitoid community is not divided into relatively discrete subwebs with largely independent dynamics, and that species in the same taxonomic order are more likely to interact indirectly.

Does organic farming benefit biodiversity

Predator biodiversity strengthens herbivore suppression.

This study suggests a harmonious relationship between predator conservation and herbivore control, and a relatively weak role for predator interference, within this community.