Transcript Slide 1

Coastal development impacts on biological communities
in the Chesapeake Bay
Examples from the Atlantic Slope Consortium
R-82868401
Atlantic Slope Consortium (ASC) = An Estuarine Indicator Research Program
Cast of many…
Smithsonian Environmental Research
Center (SERC): Bill Deluca, Pete Marra,
Don Weller, Tom Jordan, Tuck Hines,
Chuck Gallegos, Ryan King, Matt Baker
Virginia Institute of Marine Science
(VIMS): Donna Marie Bilkovic, Carl
Hershner, Molly Roggero
Penn State University: Rob Brooks,
Denice Wardrop
Goal: To develop a suite
of ecological and socioeconomic
indicators for assessing
and managing the condition of
the vital resources in the
Mid-Atlantic region
Coastal development leads to disruption of ecosystem services…
Coastal development
and deforestation
reduce the filtration
capacity of the riparian
zone which impacts the
littoral zone
Natural System
Shoreline
Littoral
Loss of ecosystem
function and structure
due to coastal
development
Biota
Developed=Broken Links
Broken Links lead to
decreases in biodiversity
and functional groups that
reduce resilience, and the
ability of the communities
to respond to external
drivers such as climatic
events
Shoreline
Wetland loss
Forest loss
Nutrient input
Littoral
Water clarity
DO
Terrestrial inputs
Aquatic vegetation
Biota
Biodiversity
Functional groups
Resilience
ASC Goal: to identify linkages between patterns of land use
and environmental indicators in estuarine habitats.
• “Estuarine
segments”:
Watersheds
and
subestuaries
of a larger
estuarine
ecosystem
• Segment
Developed
Agricultural
Mixed-Developed
Mixed-Agricultural
Forested
land-use
ranges from
forested to
highly
agricultural
or developed
Potential environmental indicators of the health of the Bay
Indicator
Watershed
Stream nutrients
X
Stream
macroinvertebrates
X
Estuarine water quality
X
Benthic IBI
X
X
Fish IBI
X
X
Phragmites abundance
X
X
Blue crab abundance
X
X
PCB in White perch
X
Waterbird IBI
X
X
X
X
Wetland Bird IBI
SAV abundance
Local land use
X
Fish Communities and Habitat
p<0.001; all different
6
7
Fish Community Index (FCI)
Fish Community Index (FCI)
7
5
4
3
2
1
0
p=0.003; High vs. Minimal
6
5
4
3
2
1
0
Abundant
Moderate
Low
Available subtidal habitat
Higher FCI scores were
associated with increasing
abundance of subtidal habitat
Bilkovic et al. 2005
Minimal
Moderate
High
Amount of Alterations to Shoreline
FCI scores were lower at sites
with highly altered shorelines
versus natural shorelines.
Invasive Species and Development
Phragmites abundance estimate
7
6
5
4
3
r2 = 0.61, P < 0.001
2
Developed
Mixed-Dev
Agricultural
Mixed-Ag
Forested
1
0
0
20
40
60
% Developed Land in Watershed
Whigham et al. 2005
80
White Perch and PCBs
Total PCBs in White Perch (ng/g)
1000
0.067x
y = 10.3e
2
R = 0.77
no consumption
recommended*
100
0.5 meal/mo
1 meal/mo
10
Developed
Agricultural
Mixed-Developed
Mixed-Agricultural
Forested
1
0
20
40
60
80
Percent Developed Land in Watershed
Total PCBs in white perch in relation to percent developed land in the
watershed. USEPA (1999) guidelines for cancer health endpoints.
King et al. 2004
Juvenile Blue Crabs and Habitat
King et al. 2005
Juvenile blue crabs (< 3 in) were most
abundant at sites with extensive shoreline
wetlands, forested watersheds, and subestuaries with average salinity > 16 ppt.
Changepoint Analysis—
Assessing Ecological Thresholds
100
BIBI in the Nearshore
5
Cumulative Probability Curve
80
4
60
3
40
2
1
20
0
0
0
20
40
60
80
Developed riparian land use (%)
100
Negative macrobenthic community responses occurred when developed
shorelines were 10% or higher.
Bilkovic et al. 2006
Cumulative probability of change point
6
Increasingly positive
scores=more diverse,
pollution-sensitive taxa
Increasingly Negative
score = taxa associated
with impaired streams
King et al. 2005
21-32% Dev. threshold
1-22% Local Dev. threshold
Cumulative Probability of A Threshold
Development appeared to
have its greatest effect on
stream macroinvertebrates
when close to the sampling
station, where it contributes
to riparian degradation and
reduced woody-debris input.
Stream macroinvertebrate dissimilarity scores
Stream Macroinvertebrates and Development
100
Marsh Bird Community Integrity
High
50
Low
0
0
25
50
Cumulative Probability of a Threshold Occurring
Marsh Bird Integrity and Development
Percent Development within 500m of a Wetland
When 15% of the land within 500 m of a marsh was developed there
was a significant decline in Marsh Bird Community Integrity.
DeLuca et al. 2004
Ecological Thresholds of Communities
1
Probability of Change
Invert IBI
0.8
Phrag abundance
Water bird index
0.6
Wetland bird index
0.4
Benthic IBI
0.2
1
5
10
15
20
25
30
35
40
45
50
55
60
65
70
76
80
85
90
95
100
0
% Development
Sources (SERC; VIMS): Dennis Whigham, Donna Marie Bilkovic, Ryan King, Bill Deluca, Peter Marra, Matt Baker,
Don Weller, (Figure from Dennis Whigham)
Threshold analyses: Qian et al. 2003 (Ecol. Mod.); King and Richardson 2003 (Env. Man.)
Do Biota Respond to Variations in Nearshore Condition?
YES--Our research indicated that structural and functional changes
in biological communities occurred in relation to alterations in
subtidal habitat, shoreline condition, and/or land use.
SUMMARY
► Both the amount of development and its
proximity to the estuary or wetland
contributes to degradation of aquatic
resources.
►In general, > 20% development (at local
and/or watershed levels) was related to
shifts in biological communities (indicators),
revealing possible ecological thresholds
►Forest buffers were also noted to reduce
sediment and nutrient loads along stream
corridors or around wetlands
►In many instances, local development had
stronger links with the aquatic resource
than watershed development
FINAL ASC REPORT ONLINE:
http://www.asc.psu.edu/public/pubs/_Final%20Report_AtlanticSlopeConsortium.pdf