Tree-soil interactions and the provision of soil-mediated ecosystem services

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This presentation was given by Edmundo Barrios at the World Agroforestry Congress in New Delhi. 10-14 February 2014.

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  • Essentially what this technique allows us to do is to analyze many hundreds of samples simultaneously with the community in each sample (bacterial or eukaryotic) analyzed in depth. We typically end up with more than 1500 sequences per sample. of the ssu rRNA gene with each sample receiving a unique 12 bp error-correcting barcode of the ssu rRNA gene with each sample receiving a unique 12 bp error-correcting barcodeDescription of barcoded pyrosequencing. 16s for bacteriaSequences belonging to each sample identified using the barcodesof the ssu rRNA gene with each sample receiving a unique 12 bp error-correcting barcode
  • Tree-soil interactions and the provision of soil-mediated ecosystem services

    1. 1. Session 5.3 Biodiversity and agroforested habitats
    2. 2. Ecosystem Functions, Goods and Services de Groot et al 2002
    3. 3. Habitat provision by trees • Microclimate buffering
    4. 4. Habitat provision by trees • • • • • • Microclimate buffering Nutrient availability Water availability Provision of C substrates Host for pollinators Host biological control agents
    5. 5. Habitat provision by trees Pres. #4,#5,#6 Pres. #1,#2,#3 TREE-BGBD WaNuLCAS TREE-AGBD
    6. 6. Tree-soil interactions and the provision of soil-mediated ecosystem services Edmundo Barrios, Fred Ayuke, Diana H. Wall, Scott Bates, Noah Fierer, Keith Shepherd University of Nairobi GSBI Global Soil Biodiversity Initiative
    7. 7. OUTLINE 1. Biodiversity management in agricultural landscapes 2. Land health surveillance framework 3. Challenges and opportunities
    8. 8. BIODIVERSITY MANAGEMENT IN AGRICULTURAL LANDSCAPES Planned and managed AGBD aboveground biodiversity Above-ground: planned, managed biodiversity ? BGBD Unplanned, unmanaged Below-ground: unplanned, unmanaged biodiversity belowground biodiversity ? ? Diversitas 2005
    9. 9. Why bother about Soil Biota when considering Ecosystem Services? Primary driving agents of nutrient cycling (C, N, P, S) Regulators of dynamics of: soil organic matter carbon sequestration greenhouse gas emissions Modify soil physical structure and water regimes Enhance amount & efficiency of nutrient acquisition of plants (Symbiosis) Influencing plant health (pathogens & pests vs. natural predators & parasites) (Barrios 2007)
    10. 10. SOIL BIOLOGICAL FUNCTION AND THE PROVISION OF ECOSYSTEM SERVICES Barrios et al, 2012
    11. 11. What about trees and soil-based ecosystem services? Strong linkage between aboveground biodiversity (vegetation/crops) and belowground biodiversity (soil organisms) Great potential to strategically utilize land use and management systems to influence the provision of ecosystem goods and services
    12. 12. AGROFORESTRY Close to half of agricultural land has > 10% Tree cover (Zomer et al 2009)
    13. 13. Some effects of trees are mediated through impact on soil biota – trees increase abundance Mean density of different soil biota and calculated response ratios Agroforestry Soil macrofauna Earthworms Beetles Centipedes Termites Ants Soil mesofauna Collembola Mites Soil microfauna Non-parasitic nematodes Parasitic nematodes Agriculture RR References (indiv m-2) 54.4 20.9 2.7 90.7 23.2 (indiv m-2) 17.6 9.6 0.5 81.0 8.6 3.1 2.2 5.6 1.1 2.7 1,2,3,4,5,6 1,2,5 1,2,5 1,2,5 1,2,5 (indiv m-2) 3890.1 5100.7 (indiv m-2) 2000.7 1860.1 1.9 2.7 7 7 (indiv liter-1) 2922 203.7 (indiv liter-1) 1288 211.5 2.3 1 8 8 Barrios et al. 2012
    14. 14. Some effects of trees are mediated through impact on soil biota – trees increase activity Greater soil biological activity (earthworms) near trees but effect greater for some tree species than others Pruned trees Free growing trees Earthworm cast weight Sample with no earthworm casts Pauli et al 2010
    15. 15. TREES AS HOTSPOTS OF BIOLOGICAL ACTIVITY IN AGRICULTURAL LANDSCAPES Barrios et al. 2012
    16. 16. Land Health Surveillance AfSIS - A Globally Integrated African Soil Information Service (www.africasoils.net) International Center for Tropical Agriculture (CIAT) Tropical Soil Biology and Fertility Institute (TSBF), Earth Institute at Columbia University, World Agroforestry Centre (ICRAF), International Soil Reference Information Centre (ISRIC) With support from Bill & Melinda Gates Foundation and Alliance for a Green Revolution in Africa (AGRA)
    17. 17. AfSIS Sentinel Sites 10 km Cluster#4 Cluster#8 Cluster#12 Cluster#16 Cluster#3 Cluster#7 Cluster#11 Cluster#15 10 km Cluster#2 Cluster#6 Cluster#10 Cluster#14 Cluster#1 Cluster#5 Cluster#9 Cluster#13 SENTINEL SITE (100 km2)
    18. 18. 2.5 Km CLUSTER (1 km2) 2.5 Km Plot 1000 m2 Subplot #2 Subplot #1 Subplot #3 Sub-plots 100 m2 Subplot #4
    19. 19. Sampling plot (1000 m2) sub-plots (100 m2) SOIL BIOTA
    20. 20. D ocumentation of AfSI S methods and guidelines for implementation
    21. 21. LDSF characterization of Woody Cover PLANTS T-square method Tree density, basal area, biovolume and biomass
    22. 22. Tree Density Mapping at Fine Resolution Map of tree density in an areas with steep climatic gradients in northern Kenya, derived from modeling ground data collected from sentinel sites to Landsat imagery (28.5 m resolution).
    23. 23. AfSIS Soil Characterization • • • High throughput system Infrared spectroscopy on all samples Reference samples on subsets
    24. 24. Measuring Soil Carbon in Landscapes 1988 2006
    25. 25. Soil Biological Properties Soil samples 0-20 cm, 20-50 cm Composited per plot (1000 m2) Soil monoliths One per subplot (100 m2) Soil analysis Soil DNA analysis (dry soil) Soil macrofauna 25 cm Soil DNA analysis (DESS soil) 20 cm Soil analysis Systematic assessment of Local Ecological Knowledge on tree-soil biota interactions Barrios et al., 2013
    26. 26. Soil macrofauna distribution Spatial distribution of earthworms across a Sentinel Site Dark circles = presence, light circles = absence
    27. 27. Pyrosequencing DNA extracted from soil samples -High throughput system -PCR amplification with group specific primers for SSU rRNA gene -Pyrosequencing gives ~1500 sequence per sample across many samples (>450,000 seq per run) - Illumina (MySeq 5 million seqs per run) -Taxonomic Information per sample AGCCTTAA… AGCCTTAA… AGCCTTAA… GCTACCAT… GCTACCAT… GCTACCAT… CGGATCAC… CGGATCAC… CGGATCAC… CTCGATTC… CTCGATTC… CTCGATTC…
    28. 28. Soil total N Bradyrhizobium DNA sequences Heat map showing the levels of total % N in soil (left) as well as abundance of DNA sequence types representing Bradyrhizobium (right) at Sentinel Site
    29. 29. CHALLENGES & OPPORTUNITIES Developing better understanding of AGBD/BGBD interactions Recommendations of what types of tree densities, arrangements and species maintain essential ecosystem functions provided by soil biota in agricultural landscapes.
    30. 30. Identifying, Quantifying and Mapping Host Spots of Biological Activity and Ecosystem Services Temporal and spatial dynamics as a result of environmental factors in situ Predictive knowledge of Ecosystem Service Provision
    31. 31. Developing Local Soil Health Monitoring Systems to evaluate Ecosystem Service provision performance Allow rural communities, environmental/agricultural institutions and local government Prepare for negotiations related to Payment for Ecosystem Services
    32. 32. Thank you!

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