Dr. Carl Rosier
Delaware Environmental Institute
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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
A. Aufdenkampe, J. Kan, D. Levia,
and J. Van Stan
S. Hicks, D. Montgomery
A. Roberson and G. Rosier
Canopy manipulation of precipitation and leafs leaching capacity
Interception
Evaporation
-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
-5-15% of precipitation is absorbed by leaves
and directed down plant stem
-Highly concentrated in nutrients due to leaf
Stemflow
and stem contact
-Homogeneous distribution of nutrients at
stem base
Bark texture effects stemflow and throughfall potential
American Beech
Yellow Poplar
Leaf Area effects stemflow and throughfall potential
American Beech
Photo: biology.missouristate.edu/herbarium
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). Medium for Plant Growth
Site of Biological Diversity
Recycler of Nutrients
Storage of Global CO2
Water purification
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?
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, codominated by Fagus grandifolia Ehrh. (American
beech) and Liriodendron tulipifera L. (yellow poplar)
Decagon soil
moisture probes
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-summer
Dormancy-winter
0.52
0.32
Soil Moisture (%)
Beech
Poplar
Rainfall (mm)
0.30
0.48
0.46
8
6
0.28
0.44
0.42
0.26
4
0.40
0.24
0.38
2
0.36
0.22
0.34
0.32
0
0.20
0
5
10
15
20
0
Hours
5
10
15
20
Rainfall (mm)
0.50
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
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 8rainfall events spanning 6-months.
Soils experiencing Stemflow
maintain grater rates of CO2
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
< 20m
3x
YP
AB
Bulk Soil
(0-10 cm)
DNA
Polymerase Chain Reaction:
Universal primers used to
amplify bacteria and fungal
communities
DNA
PCR
DGGE
DNA
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
(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
(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 leafout in some trees
Fungal communities
associated with YP
trees shift towards
similarity during
winter
This is suggestive of
canopy effects on
fungal communties
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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