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