Assessing the Effects of Canopy-derived Nutrient Fluxes on Key Soil Ecosystem Services

1. Assessing the Effects of Canopy-derived Nutrient Fluxes on Key Soil Ecosystem Services Dr. Carl Rosier Delaware Environmental Institute

2. Overview • Define Canopy-derived nutrient flux • Briefly discuss soil ecosystem services • Review, results and findings from a study where we try to connect canopy influences to soil processes Acknowledgements • A. Aufdenkampe, J. Kan, D. Levia, and J. Van Stan • S. Hicks, D. Montgomery • A. Roberson and G. Rosier

3. -5-15% of precipitation is absorbed by leaves and directed down plant stem -Highly concentrated in nutrients due to leaf and stem contact -Homogeneous distribution of nutrients at stem base Exactly what is Canopy-derived nutrient flux? Canopy manipulation of precipitation and leafs leaching capacity Evaporation Interception -10-50% of precipitation is intercepted tree canopy -0% nutrient gain by the soil environment Throughfall -10-50% of precipitation absorbed by leaves and drips to the ground -90% nutrient gain by the soil environment -Heterogeneous in distribution Stemflow

4. Bark texture effects stemflow and throughfall potential American Beech Canopy-derived nutrient fluxes vary: tree morphology Yellow Poplar

5. Canopy-derived nutrient fluxes vary: tree morphology Leaf Area effects stemflow and throughfall potential American Beech Photo: biology.missouristate.edu/herbarium Yellow Poplar Photo: biology.missouristate.edu/herbarium

6. What is a Soil Ecosystem Service? Medium for Plant Growth Site of Biological Diversity Recycler of Nutrients Soils are a multi-functional resource that provide a range of ecosystem goods and services (Center Ecology & Hydrology). Storage of Global CO2 Water purification

7. Why do we care if the Canopy has an influence on Soil Processes? Sequestration of global CO2 – Soils represent a significant storage reservoir of Carbon. However, the mechanisms controlling soil potential to store Carbon are not completely known. Understanding how individual tree species affect overall soil-C would provide greater realism of soil C-budgets for mixed species watersheds Invasive plants – Plants can condition their home soils by controlling: organic matter turnover, nutrient cycling, water storage These factors are tightly coupled to the organisms living in the soil Understanding these processes increases the potential to restore native plant communities

8. Research Questions (a) Do soils experience greater soil moisture in the presence of stemflow compared to throughfall. Is there a seasonal effect? (b) Do ecohydrological processes influence soil respiration and what effect does this have on soil-c storage? (c) Do soils experiencing different ecohydrological processes maintain different microbial communities? Research Area: The study plot is within the Fair Hill Natural Resources Management Area (NRMA) in northeastern Maryland (39°42′N, 75°50′W) The forest canopy is broadleaved deciduous, co-dominated by FagusgrandifoliaEhrh. (American beech) and Liriodendron tulipifera L. (yellow poplar)

9. Decagon soil moisture probes Soil Moisture: 3-Decagon soil moisture probes were installed at the tree bole of one-American beech (AB) and one-Yellow poplar (YP) < 20m YP AB • Leafout- AB soils gain 10% increase in soil water when compared to YP • During leafout AB soils dry quicker possibly due to root adsorption • Dormancy results in only a 3% increase in AB soil water compared to YP

10. Soil Respiration: Fig. (a): CO2 mineralization rates for AB and YP during four separate precipitation events. Fig (b): YP and Fig (c); AB throughfall and stemflow quality assessed by DOC/DON and Aromaticity. Values were averaged over 8-rainfall events spanning 6-months. Soils experiencing Stemflow maintain grater rates of CO2

11. 3 trees per specie were sampled; 6-total trees Tress were sampled at three intervals; summer, winter, and spring Bacterial and Fungal Molecular Analysis DNA: extracted from soil samples using Power TM Soil DNA Kit (MO BIO Laboratories) This yields total DNA < 20m 3x YP AB Bulk Soil (0-10 cm) DNA DNA DNA Polymerase Chain Reaction: Universal primers used to amplify bacteria and fungal communities 3-samples per tree at each sampling interval. Samples were pooled prior to DNA extraction PCR DGGE Density Gradient Gel Electrophoresis: molecular technique that uses the isoelectric point of DNA and GC content to isolate specific strands of DNA

12. Bacterial Community Analysis: Summer Samples (A) The dendrogram of hierarchical cluster analysis based generated by GelCompare II software (B) DGGE banding pattern of total bacterial DNA extracted from AB, YP and Open Canopy soils. AB and open canopy treatments maintain very similar bacterial communities YP treatments maintain dissimilar bacterial communities suggestive that the uneven allocation of canopy resources may be influencing the heterogeneous structure of bacterial communities associated with YP trees

13. Fungal Community Analysis: Seasonal Samples The dendrogram and DGGE banding pattern of AB soils for three seasons (B)The dendrogram and DGGE banding pattern of YP associated soils Fungal communities associated with AB trees shift towards dissimilarity during spring This could be the result of delayed leaf-out in some trees Fungal communities associated with YP trees shift towards similarity during winter This is suggestive of canopy effects on fungal communties

14. Summary • Stemflow: alters several soil process providing American Beech with a competitive advantage over other tree species • Throughfall: disproportionate allocation, and recalcitrant nature on throughfall inputs from Yellow Poplar drives the dissimilarity of microbial communities