Stream Community Structure: An Analysis of Riparian Forest
Buffer Restoration in the Chesapeake Bay Watershed
Leslie Orzetti, PhDEcosystem Solutions, Inc.
Outline
Background Forest Buffer Zones Benthic Macroinvertebrates Chesapeake Bay
Hypotheses Methods Results Discussion
What is a forest buffer? Chesapeake Bay Program Definition
Areas of trees, shrubs and other vegetation, that are adjacent to a body of water, that are managed for several purposes
Benthic Macroinvertebrates: Nature’s Water Quality Indicators
What are they? Why do we want to use bugs? What affects them?
Water quality Habitat
How do we use them? Metrics
Benthic Macroinvertebrate Metrics
Composition Tolerance Feeding Habit
% EPT
% Plecoptera
% Ephemero
% Trichoptera
EPT/Chiro
Taxa Richness
No. intolerant families
% Tolerance
% Dominance
FBI
% Scrapers
% Predators
% Gatherers
% Filterers
% Shredders
Scraper/Filter
% Burrowers
% Clingers
% Climbers
% Sprawlers
% Skaters
% Swimmers
• Does stream water quality and habitat improve with relative age of restored forest buffer?
• Does stream benthic community increase in diversity and richness with age of restored buffer?
• Does stream benthic community diversity and richness increase with improved ambient water quality and habitat?
Hypotheses
Sites
• How big are they?– First order streams
• Where are they?– Piedmont physiographic
region– Frederick, Carroll,
Loudon, Fauquier, Fairfax, Prince William Counties
Okajangus, 1982
Sites with no buffer
Garrett
Wacopin
Sites 1-2 Years Old
Harbaugh
Stull
Sites 4-6 Years Old
FriendRoyer
Sites Older than 10 Years
Monocacy NRMA
Johnny Moore
Control SitesPrince William Forest Park
Field Methods
• 150 m reach in buffer zone
• In situ water quality– DataSonde Hydrolab
• Water samples
• Benthic invertebrate collection
• Habitat characterization
• Landuse characterization
Laboratory Methods
• Nutrient analysis– Nitrogen– Phosphorus
• Solids analysis
• Benthic invertebrate analysis– Identification– Metrics
RESULTS
Habitat Results
0 10 20 30 40 50 60Buffer Age (years)
50
100
150
200
Hab
i tat
score
Buffer Age Class
50
100
150
200
Hab
i tat
Sc o
re
Habitat
Popes Head
Catharpin
Water Quality PCA: Age
PCA Axes 1 and 3: Suite 1 Water Quality by Age
B
BBB
B
B
B
B
B
A
AAA
AA
A
A
AAA
AAA A
A AAA
A AA
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Axis 1
Axis
3
A = Under 10 Years OldB= Over 10 Years Old
Water Quality PCA: Landuse
PCA Axes 1 and 3: Suite1 Water Quality by Landuse
P
P
F
R
F
A
P
R
A
S
S
F
P
F
PP
SR S
A
F
P
P
PP
P
PSS
R
S
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Axis 1
Ax
is 3
R = RuralP = PastureA = AgricultureF = ForestS = Suburban
Water Quality PCA: Buffer Width
PCA Axes 1 and 3: Suite 1 Water Quality by Buffer
O
O
U NU
O
N U
U
U
OO
UO
N
U N
O
O
O
U
N
O
O
O
O
U
O
O
O
O
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Axis 1
Ax
is 3
N = No bufferU = Under 50 feetO = Over 50 feet
Water Quality Discriminant Analysis
Less th
an 10
Over 1
0
Buffer Age Class
-4
-3
-2
-1
0
1
2
3
Can
onic
al S
cor e
Composition and Tolerance PCA: Age
PCA Axes 1 and 2 Benthic Macroinvertebrates by Age
AA
AAAA
A AAA BAAA
AAAA A
AA A
A
B
B
B
BB B
B
B-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Axis 1
Ax
is 2
A = Under 10 Years OldB= Over 10 Years Old
Composition and Tolerance PCA: Landuse
PCA Axes 1 and 2: Benthic Macroinvertebrates by Landuse
S
R
PS
PP
P R
P
PPF
A
S
S
FP F
S
S
A
RAP
FP
R
F
PP S
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Axis 1
Axis
2
R = RuralP = PastureA = AgricultureF = ForestS = Suburban
Composition and Tolerance PCA: Buffer Width
PCA Axes 1 and 2: Benthic Macroinvertebrate by Buffer Width
O
O
OU
OUOUNUU
O
O
N
OO O
U
N
O
OO-O
OU
O
O
U U NN
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
-0.6 -0.1 0.4 0.9
Axis 1
Axis
2
N = No bufferU = Under 50 feetO = Over 50 feet
Discriminant Analysis:Composition and Tolerance Metrics
Less th
an 10
Over 1
0
Age Class
-3
-2
-1
0
1
2
3
4
5
Can
oni c
al S
core
Abundance PCA: Age
PCA Axes 1 and 2: Significant Abundance by Age
AAAAA AAAAB
A AAAA A
A AA
A
AB
B
B
B
BAA
B
B
B
-0.4
-0.2
0
0.2
0.4
0.6
0.8
-1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4
Axis 1
Axi
s 2
A = Under 10 Years OldB= Over 10 Years Old
Discriminant Analysis:Abundance Data
Less th
an 10
Over 1
0
Age Class
-4
-3
-2
-1
0
1
2
Can
oni c
al S
core
Conclusions
• Habitat improved with age of buffer
• Water quality improved with age of buffer
• Benthic macroinvertebrate diversity and richness improved with age of buffer
• Benthic macroinvertebrate diversity and richness improved with ambient water quality and habitat
Conclusions
• Physical, chemical and biological components of a stream ecosystem are intrinsically linked
• Younger buffered sites have the capacity to improve with time
• Managers should see improvements within 5-10 years post restoration
Forest Buffers on DoD Installations
• DoD Legacy funded study
• Year 1 – Visited 15 field sites on 8 installations– Collected samples from 11 sites
• Benthic macroinvertebrates
• Water Quality
• Habitat
– 4 Sites unsampleable
Status of Buffers on DoD Installations
• Several installations have well maintained restored buffer areas
• Many installations have intact buffers without restoration
• Natural Resource Manager turnover and loss of restored buffer information
• Reporting of buffer miles
NRL Chesapeake
Recommendations and Future Considerations
• In-stream improvements
• Monitoring plantings
• Continued stream monitoring (every 2-3 years post restoration)
• Stream corridor preservation
• Increase buffer zone width
• Redefine forest riparian buffer zone for reporting restored buffer miles
Acknowledgements
• George Mason University
• Virginia Department of Forestry
• Maryland Department of Forestry
• Prince William Forest Park
• Lab and Field Crews
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