filling in the gaps: sedimentation and macroinvertebrate populations in headwater streams
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Filling in the Gaps: Filling in the Gaps: Sedimentation and Sedimentation and Macroinvertebrate Macroinvertebrate
Populations in Headwater Populations in Headwater StreamsStreams
Ankit Rastogi, Sarah Emel & Brigette Jones
Importance of Aquatic Importance of Aquatic SystemsSystems
BiodiversityBiodiversity Ecosystem ServicesEcosystem Services
Agriculture and industryAgriculture and industry Filtering of pollutantsFiltering of pollutants FisheriesFisheries Flood control and climate stabilizationFlood control and climate stabilization Recreation and TourismRecreation and Tourism
Anthropogenic Impacts on Sedimentation Anthropogenic Impacts on Sedimentation Construction Construction DamsDams Mining Mining Impervious SurfacesImpervious Surfaces
Impacts of Impacts of SedimentationSedimentation
Fine Sediment ParticlesFine Sediment Particles Increased turbidityIncreased turbidity Decreased light penetrationDecreased light penetration
Primary productivityPrimary productivity Clogging gillsClogging gills Clogging feeding Clogging feeding
apparatuses apparatuses Interstitial SpacesInterstitial Spaces
Decreased habitat Decreased habitat heterogeneityheterogeneity
Increased embeddednessIncreased embeddedness Increased driftIncreased drift Susceptibility to predationSusceptibility to predation
HypothesesHypotheses Results of increased sedimentation Results of increased sedimentation
in rocky-bottomed headwater stream in rocky-bottomed headwater stream systemssystems DecreasedDecreased
Total macroinvertebrate densityTotal macroinvertebrate density Species richnessSpecies richness ShreddersShredders
IncreasedIncreased Drift Drift Filter feedersFilter feeders Collector-gatherer feedersCollector-gatherer feeders
Study SitesStudy Sites Clay Brook and Hewes BrookClay Brook and Hewes Brook Upstream reference siteUpstream reference site Downstream treatment siteDownstream treatment site
Added sandAdded sand
Sampling and Sampling and MeasurementsMeasurements
DischargeDischarge EmbeddednessEmbeddedness Invertebrate driftInvertebrate drift Surber samplesSurber samples
Treatment and Treatment and ReferenceReference
InitialInitial 3 days after treatment3 days after treatment 10 days after 10 days after
treatmenttreatment
Classification and Classification and CalculationsCalculations
Classified macroinvertebrates to the Classified macroinvertebrates to the Family levelFamily level Except OligachaetesExcept Oligachaetes
Calculated total density, functional Calculated total density, functional feeding group density, and richness feeding group density, and richness from Surber samplesfrom Surber samples
Calculated drift densityCalculated drift density Compared physical features of sitesCompared physical features of sites
Physical featuresPhysical features
SiteWidth
(m)Average Depth
(m) Discharge (m3/s)
Clay Upstream 1.25 0.058 0.00622
Clay Downstream 1.22 0.068 0.00364
Hewes Upstream 1.65 0.077 0.142
Hewes Downstream 2.35 0.076 0.081
EmbededdnessEmbededdness
0
10
20
30
40
50
60
70
80
11/3 Before 11/3 After 11/06/2005 11/13/2005
Time
% E
mb
edd
edn
ess
Clay Dow nstream
Hew es Dow nstream
Clay Upstream
Hew es Upstream
DriftDrift
Site/Time (d)Up Drift density
(#/m3)Down Drift
density (#/m3)Difference (Down-
Up)
Clay 3 24.69 29.63 4.94
Clay 10 2.73 4.69 1.95
Hewes 3 14.25 2.47 -11.78
Hewes 10 1.35 4.20 2.85
Clay BrookClay Brook
0
10
20
30
40
50
60
70
80
Upper 0 Upper 3 Upper 10 Lower 0 Lower 3 Lower 10
Site/Time (Days)
Pe
rce
nta
ge
of
tota
l po
pu
lati
on
% Shredder
Predator
Filter feeder
Collector-gatherer
Hewes BrookHewes Brook
0
10
20
30
40
50
60
Upper 0 Upper 3 Upper 10 Lower 0 Lower 3 Lower 10
Site/Time (days)
Pe
rce
nta
ge
of
tota
l po
pu
lati
on
%
Shredder
Predator
Filter feeder
Collector-gatherer
Clay BrookClay Brook
0.00
500.00
1000.00
1500.00
2000.00
2500.00
Upper 0 Upper 3 Upper 10 Lower 0 Lower 3 Lower 10Site/Time (Days)
Fe
ed
ing
Gro
up
De
ns
ity
(#
/m2
)
Shredder
Predator
Filter feeder
Collector-gatherer
Hewes BrookHewes Brook
0.00
200.00
400.00
600.00
800.00
1000.00
1200.00
Upper 0 Upper 3 Upper 10 Lower 0 Lower 3 Lower 10
Site/Time (days)
Fe
ed
ing
Gro
up
De
ns
ity
(#
/m2
)
Shredder
Predator
Filter feeder
Collector-gatherer
Clay BrookClay Brook
0
200
400
600
800
1000
1200
1400
1600
1800
0 3 10
Time (d)
Den
sity (m
^-2
)
Upstream
Downstream
0
2
4
6
8
10
12
0 3 10
Time (d)
Ric
hn
ess
Upstream
Downstream
Hewes BrookHewes Brook
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
0 3 10
Time (d)
Den
sity
(m
^-2
)
Downstream
Upstream
0
1
2
3
4
5
6
7
8
9
10
0 3 10
Time (d)
Ric
hnes
s
Downstream
Upstream
SummarySummary
In Clay, ↑in all FFG’s, particularly In Clay, ↑in all FFG’s, particularly shreddersshredders
In Clay, ↑ total density, ↑ family In Clay, ↑ total density, ↑ family richnessrichness
In Hewes, ↑ predators, ↓ shreddersIn Hewes, ↑ predators, ↓ shredders In Hewes, ↑ embeddedness, ↑ total In Hewes, ↑ embeddedness, ↑ total
density, ↑ family richnessdensity, ↑ family richness
LimitationsLimitations
Small sampling sizeSmall sampling size High VariablitiyHigh Variablitiy High PatchinessHigh Patchiness
ConclusionsConclusions
Increases in sedimentation have Increases in sedimentation have strong effects, especially on species strong effects, especially on species compositioncomposition
Studies have shown decreases in Studies have shown decreases in density and family richness, while density and family richness, while we have seen the oppositewe have seen the opposite
More research should be done to More research should be done to determine the particular factors that determine the particular factors that cause either result.cause either result.
AcknowedgementsAcknowedgements
Brad TaylorBrad Taylor
Craig LayneCraig Layne
Amy DawsonAmy Dawson
Denise SteeleDenise Steele
Chelsea WoodChelsea Wood
Cayelan CareyCayelan Carey
The students of The students of Aquatic Ecology, Fall Aquatic Ecology, Fall
20052005
Dartmouth CollegeDartmouth College
Special thanks to the Special thanks to the Hanover area Hanover area
families who allowed families who allowed us to perform this us to perform this study on their landstudy on their land
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