TSECBIOSYS:

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TSEC-BIOSYS Environmental Impacts of Bioenergy
Crops in the UKwww.tsec-biosys.ac.uk Rebecca
Rowe M. Hanley, D. Goulson, G. Taylor
University of Southampton
Biomass role in the UK energy futures The Royal
Society, London 28th 29th July 2009
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Overview

• Introduction
• Knowledge gaps
• Aims
• Study sites
• Survey completed
• Key findings
• Summary main outputs

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Environmental Impacts of Bioenergy

• ? Positive impact,,? Negative Impact, ? No
  Change, Limited data
• R. Rowe, et al (2009). Renewable Sustainable
  Energy Rev. 13, 271-290

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Knowledge Gaps Willow SRC Biodiversity

• Limited information on large commercial sites
• Small non-commercial sites
• Commercial sites studied contained many young
  plantations
• Range of species
• Flora, avian, Lepidoptera and pest species well
  studied
• Soil invertebrates, mammals and non-pest
  invertebrates less well studied
• Few direct comparisons between SRC and arable
  land and none for set-aside land
• Few studies on ecosystem processes (herbivory,
  decomposition, predation)

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Aims

• To assess impacts of mature commercial willow SRC
  plantations on winged invertebrates and ground
  flora in comparison to alternative land uses
• To explore possible effects of willow SRC
  ecosystem processes

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Field Sites

• Three sites each containing
• Willow SRC plantation
• Arable field containing cereal crops
• Set-aside field
• Willow plantations
• Commercial plantations
• Greater than 5 ha in size
• Sites at least 5 years old (1998-2000)

Willow SRC
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Surveys Conducted

• Species Composition (Summer 2006)
• Winged Invertebrates (e.g. Wasps)
• Abundance
• Distribution of Orders/Size classes
• Ground Flora (Weeds)
• Species richness and abundance
• Plant strategies
• Ecosystem Processes (Summer 2007)
• Herbivory and Decomposition
• Predation (2007- 2008)

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Key Findings Winged Invertebrates

• Abundance of winged invertebrates were similar
  between land-uses,
• Invertebrates abundance in Willow SRC increased
  with height

Height
Distance
?
?
?
Land-use F2,4 0.004 P 0.96 Land-usedistances
F8,16 2.93 P 0.032
HL F4,8 10.37 P 0.003
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Distribution of Winged Invertebrate Orders
Mean number of individuals per trap (SE)
Yellow increased in willow SRC, Blue decreased
in Willow, White similar abundance in all
land-uses
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Ground Flora Species Richness Abundance

• Species richness
• Similar in all headlands
• In the cultivated area set-aside land gt willow
  SRC gt arable land
• Ground flora biomass
• Similar in set-aside and willow SRC, reduced in
  arable land

Species Richness
Biomass
F2,4 24.65 P 0.006
F2,4 13.64 P 0.016
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Plant Strategies (1)

• Fraction of plant cover provided by each of three
  plants strategies
• Life history, life form and establishment
  strategy (Grime et al.1990).

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Plant Strategies (2)

• Perennial species dominate in willow SRC

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Plant Strategies (3)

• Grass cover was highest in the headlands of all
  land-uses
• No overall effect of land-use, with all
  land-uses showing a mix of forbs and grasses

Life Form
Fraction of cover per 4m-2 quadrate
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Plant Strategies (4)

• Willow SRC higher fraction of competitive species
  few ruderal species

Establishment Strategy
Fraction of cover per 4m-2 quadrate
C F 2, 4 9.53 P 0.030, R F 2, 4 19.53 P
0.009
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Plant Strategies (5)

• In contrast to other land-uses, willow
  plantations were dominated by a mix of perennial
  grass and forbs with competitive and generalist
  establishment strategies
• Result suggest that levels of disturbance in
  willow SRC affect plant species and species
  richness

Fraction of cover per 4m-2 quadrate
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Conclusions (2006)

• Result suggest Willow SRC can help to increase
  farm scale biodiversity.
• By providing a habitat where plant species and
  invertebrate Orders uncommon in arable land can
  persist
• Are these reflected in changes in ecosystem
  processes?

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Ecosystem Processes

• The movement of nutrients, energy or matter
  between compartments within a ecosystem.
• Understand the rates of these processes is first
  step in managing ecosystems for maximum benefit
  for both biodiversity and yield.

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Methods Ecosystem Processes

• Herbivory lettuce seedlings were exposed in the
  field to assess herbivory pressure by molluscs,
  mammals and invertebrates
• Decomposition litter bags were placed in the
  field to assess decomposition rates by macro and
  meso-micro fauna (1mm, and 5mm)
• Predation fly pupae were exposed in the field to
  assess small mammal and ground invertebrate
  predation

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Key Findings Herbivory

• Summer herbivory pressure was similar in all
  land-use
• Mollusc grazing was found to be the most
  significant factor affecting seedling survival in
  all land-uses

Herbivory Pressure
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Key Findings Decomposition

• Summer decomposition rates are reduced in arable
  land in comparison to the other land-uses due to
  reduced macrofauna and mesofauna activity

Decomposition rates
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Key Findings Predation

• Predation rates highest in arable land gt willow
  SRC gt set-aside for both small mammals and ground
  invertebrates

Predation pressure
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Detailed Predation Study (2008)

• Predation assay with enclosure design to separate
  small mammals and large and small ground
  invertebrates
• Ground invertebrate activity and density
  (Pit-fall trapping and soil searches)
• Small mammal activity and density (Mark and
  recapture)
• Land-use, diurnal, seasonal

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Seasonal Predation Rates
Percentage of pupa taken
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Mammal Abundance Cultivated area
Autumn
Summer
Spring
Mean captures per site given as captures per 100
trap rounds adjusted for sprung traps
Field Vole
Wood Mouse
Pygmy Shrew
Bank Vole
Water Shrew
Common Shrew
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Mammal Abundance Cultivated Area
Autumn
Summer
Spring
ns
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Mammal Abundance Cultivated Area
Autumn
Summer
Spring
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Small Mammal Breeding
Percentage of individuals trapped
16 21 49 5 8 6 40 9
Number of individuals
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Summary of Key Outputs

• Assessed the current knowledge bases on the
  environmental impacts of bioenergy crops (Rowe et
  al 2009)
• Mature commercial willow SRC plantations are
  beneficial for farm-scale biodiversity
• Variation in the winged invertebrate and plant
  communities of willow SRC in comparison to
  alternative land-uses
• Highlighted the relative important of small
  mammals in predation in willow SRC
• Identified willow SRC as a breeding site for
  several small mammal species.

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Acknowledgments

• Land Owners,
• Russell Fraser, Dave Barrett and Fred Walter
  (CRL)
• Field Assistance
• Suzie Milner, Alex Wan, Sarah-Jane Yorke, Matt
  Aylott, Lisa Durrant, Stefan George, Katie Finn,
  Stacey Travers, Judy Gallimore, Carl Wardill, Jo
  Seymour, Matt Guy, Dr Donna Clarke
• Supervisors
• Prof. Gail Taylor, Dr. Mick Hanley, Dr. Dave
  Goulson
• NERC and TSEC

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Thank you for your attention!
www.tsec-biosys.ac.uk