Biodiversity

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• Biodiversity
• focus on function

Felix Wäckers
Centre for Sustainable Agriculture
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Biodiversity
Federal Environment Minister Sigmar Gabriel
Agriculture and nature conservation must find
ways to work together hand-in-hand."
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Agriculture and the Environment

• Loss of Biodiversity

• On the landscape level
• Larger fields
• Loss of non-crop elements

• On the field level
• Fewer crop varieties
• Use of agrochemicals

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Agri Environment Schemes
Source RSPB, BTO, DEFRA
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Guardian, Wednesday May 7 2008
Wheat price

• Increasing commodity prices put
  agri-environment schemes under pressure as
  the economic return (subsidies) for uncropped
  land is outweighed by crop value.

The 500,000 hectares of set-aside land and other
uncropped land in England has dropped to an
estimated 250,000 hectares this year. As a result
many plants and animals are at risk.
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• Functional Biodiversity

Agriculture and the Environment

• biological pest control
• pollination
• water use efficiency
• erosion control
• nutrient cycling

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Functional Biodiversity

• Biodiversity on the scale of agricultural fields
  or landscapes,
• which sustains agricultural production 
• and other ecosystem services. 

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How to optimize services?
Traditional paradigm Enhance diversity
(diversity services)
Pimentel, D. (1961) Diversity-Stability
hypothesis The stability of a community
increases with increasing biological diversity
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Blackbox
Ecosystem Services
Biodiversity
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Andow D.A. (Ann. Rev. Entomol. 36
561-586)Vegetational diversity and arthropod
population response
Does it work?

• 52 of published studies on agroecosystem
  diversification report reduced pest populations
• 33 had no effect or variable effects
• 15 resulted in increased pest populations.

Effects variable and unpredictable
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How to optimize services?
Traditional paradigm Enhance diversity
Functional biodiversity Selectively enhance
diversity
Different organisms have different requirements

• Identify resource requirement of target
  organisms providing ecosystem services
• Identify resource bottlenecks in the
  agro-ecosystem
• Change the agro-ecosystem to alleviate these
  constraints

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Bottleneck Lack of nectar and pollen in many
cropping systems
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Consumer benefits
The impact of nectar sources on biocontrol
efficacy
Basic and Applied Ecology 7 (2006) 133140
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Biological control agents depending on
nectar/pollen feeding.


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Do diverse bird conservation margins benefit
biological pest control?
Meteorus autographae
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(No Transcript)
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Conclusions
ug/wesp

• High diversity field margins for bobwhite quail
  conservation failed to provide food to a
  biological control agent and did not enhance
  biological pest control in the adjacent crop.
  Parasitoids did clearly benefit from pure
  stands of cahaba white vetch. Impact on
  Biocontrol is a function of flower
  suitability, rather than diversity.

Journal of Applied Ecology 44 (2007) 13-21
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Not all flowering plants provide suitable food
for all insects
Biological Control 29 (2004) 307314 Proc.
Experimental Applied Entomology 6 (1996)
106-112.
Vicia sativa
Select to optimize BC benefits
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Enhancing biological control
Without supporting pests?
Journal of Insect Physiology, 47 (2001) 1077-1084
Entomologia Experimentalis et Applicata 115
(2006) 187192
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Pest
Biological control agent
(Winkler, Wackers van Lenteren, in press)
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Study individual plant species with regard to
the resources they provide
Summary

• Focus on benefits to biological control agents
  and/or pollinators while also considering
  insect pests, pathogens and weed pressure

• Based on these studies generate (crop-) specific
  seed mixtures

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Functional agro-biodiversity (FAB).
IOBC wprs Bulletin 34125-138