dr. carl rosier delaware environmental institute
TRANSCRIPT
Assessing the Effects of Canopy-derived Nutrient Fluxes on Key Soil Ecosystem
Services
Dr. Carl Rosier Delaware Environmental Institute
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
Overview
Acknowledgements A. Aufdenkampe, J. Kan, D. Levia,
and J. Van Stan S. Hicks, D. Montgomery A. Roberson and G. Rosier
Exactly what is Canopy-derived nutrient flux?
-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
Evaporation
Throughfall
Stemflow
Interception
Canopy manipulation of precipitation and leafs leaching capacity
-10-50% of precipitation is intercepted tree canopy
-0% nutrient gain by the soil environment
-10-50% of precipitation absorbed by leaves and drips to the ground
-90% nutrient gain by the soil environment
-Heterogeneous in distribution
Canopy-derived nutrient fluxes vary: tree morphology Bark texture effects stemflow and throughfall potential
American Beech
Yellow Poplar
Canopy-derived nutrient fluxes vary: tree morphology Leaf Area effects stemflow and throughfall potential
Photo: biology.missouristate.edu/herbarium
American Beech
Yellow Poplar
Photo: biology.missouristate.edu/herbarium
Soils are a multi-functional resource that provide a range of ecosystem goods and services
(Center Ecology & Hydrology).
What is a Soil Ecosystem Service?
Recycler of Nutrients
Water purification
Medium for Plant Growth Site of Biological Diversity
Storage of Global CO2
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
(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 Questions
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 Fagus grandifolia Ehrh. (American beech) and Liriodendron tulipifera L. (yellow poplar)
Hours
0 5 10 15 20
Soi
l Moi
stur
e (%
)
0.32
0.34
0.36
0.38
0.40
0.42
0.44
0.46
0.48
0.50
0.52
0 5 10 15 200.20
0.22
0.24
0.26
0.28
0.30
0.32
Rai
nfal
l (m
m)
0
2
4
6
8BeechPoplarRainfall (mm)
Leafout-summer Dormancy-winter
Soil Moisture:
YP AB
< 20m
3-Decagon soil moisture probes were installed at the tree bole of one-American beech (AB) and one-Yellow poplar (YP)
Decagon soil moisture probes
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
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
Bacterial and Fungal Molecular Analysis
YP AB
Bulk Soil(0-10 cm)
< 20m
3x
DNADNA DNA
PCR
DGGE
3 trees per specie were sampled; 6-total trees
Tress were sampled at three intervals; summer, winter, and spring
DNA: extracted from soil samples using Power TM Soil DNA Kit (MO BIO Laboratories)
This yields total 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
Density Gradient Gel Electrophoresis: molecular technique that uses the isoelectric point of DNA and GC content to isolate specific strands of DNA
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
Fungal Community Analysis: Seasonal Samples (A)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
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