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T SEC-BIOSYS: Environmental Impacts of Bioenergy Crops in the UK www.tsec-biosys.ac.uk Rebecca Rowe M. Hanley, D. Gouls

Study on environmental impacts of willow SRC plantations compared to arable and set-aside land uses, focusing on biodiversity, ecosystem processes, and potential benefits. Key findings highlight plant strategies, species richness, herbivory, and more.

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T SEC-BIOSYS: Environmental Impacts of Bioenergy Crops in the UK www.tsec-biosys.ac.uk Rebecca Rowe M. Hanley, D. Gouls

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  1. 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

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

  3. Environmental Impacts of Bioenergy •  Positive impact,, Negative Impact,  No Change, * Limited data • R. Rowe, et al (2009). Renewable & Sustainable Energy Rev. 13, 271-290

  4. 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)

  5. 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

  6. 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

  7. 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)

  8. 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-use*distances F8,16 = 2.93 P 0.032 H*L F4,8 =10.37 P 0.003

  9. Distribution of Winged Invertebrate Orders Mean number of individuals per trap (SE) Yellow increased in willow SRC, Bluedecreased in Willow, Whitesimilar abundance in all land-uses

  10. Ground Flora: Species Richness & Abundance • Species richness • Similar in all headlands • In the cultivated area set-aside land > willow SRC > 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

  11. 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).

  12. Plant Strategies (2) • Perennial species dominate in willow SRC Life History Perennial Annual Fraction of cover per 4m-2 quadrate

  13. 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 Grass Forb Fraction of cover per 4m-2 quadrate

  14. Plant Strategies (4) • Willow SRC higher fraction of competitive species few ruderal species Establishment Strategy Competitive Ruderal Stress Tolerate Generalist Fraction of cover per 4m-2 quadrate C+ F2, 4 = 9.53 P = 0.030, R+ F2, 4 = 19.53 P= 0.009

  15. 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 Competitive Ruderal Stress Tolerate Generalist Fraction of cover per 4m-2 quadrate

  16. 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?

  17. 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. Seedling Survival Plant Species Nitrogen Cycling Carbon Storage Pest Species Density Mammal and Avian Diversity Herbivory Pressure

  18. 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

  19. 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 Willow SRC Arable Set-aside

  20. 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

  21. Key Findings: Predation • Predation rates highest in arable land > willow SRC > set-aside for both small mammals and ground invertebrates Predation pressure

  22. 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

  23. Seasonal Predation Rates Percentage of pupa taken

  24. Mammal Abundance Cultivated area Autumn Summer Spring Mean captures per site given as captures per 100 trap rounds adjusted for sprung traps Field Vole Bank Vole Wood Mouse Water Shrew Pygmy Shrew Common Shrew

  25. Mammal Abundance Cultivated Area Autumn Summer Spring ns

  26. Mammal Abundance Cultivated Area Autumn Summer Spring

  27. Small Mammal: Breeding Percentage of individuals trapped 16 21 49 5 8 6 40 9 Number of individuals

  28. 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.

  29. 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

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

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