A Synthesis of the Impacts of Contemporary Forest Practices on Aquatic Ecosystems at a Watershed Scale: A Case Study from Hinkle Creek A Skaugset, M Adams, D Bateman, K Cromack, L Ganio, B Gerth, B Gresswell, J Li, S Meininger, A Simmons, C Surfleet, and N Zegre
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A Synthesis of the Impacts of Contemporary Forest Practices on Aquatic Ecosystems at a Watershed Scale: A Case Study from Hinkle
Creek
A Skaugset, M Adams, D Bateman, K Cromack, L Ganio, B Gerth, B Gresswell, J Li, S Meininger, A Simmons, C Surfleet, and N Zegre
ResearchersGraduate Students• Aaron Berger• Becca Miller• Fey Egan• Hazel Owens• Kelly Kibler• Lance George• Mark Novick• Matt Meadows• Niels Leuthhold• Nick Som• Nicolas Zegre• Scott Meininger• Tim Otis
P.I.s• Arne Skaugset• Bob Gresswell• Judy Li• Kermit Cromack• Lisa Ganio• Mike Adams
Faculty Research Assistants• Alex Irving• Amy Simmons• Bill Gerth• Chris Surfleet• Dave Leer• Doug Bateman• Emily Sinkhorn• Janel Sobota• Nicolas Zegre• Rich Van Driesche• Steve Clark• Tim Royer
And our many field crews, lab technicians, and associates.
Thank you!
Physical Setting
• Foothills of the southern Oregon Cascades• Igneous geology (basalt and rhyolite flows)• Deep, well-drained gravelly to clay loam soils• Mean annual precipitation (MAP) ~ 1,480 mm (58 in)• 60-year old, harvest regenerated, Douglas-fir forest• Owned and managed by Roseburg Forest Products.
2005 – 2006• Adjacent to non-fish-bearing streams• 152 ha (380 acres) of clearcuts in 5
units• 12.2 mmbf and 3,281 loads of logs
2008 - 2009 treatments:• Adjacent to fish-bearing tributaries and
main stem• 131 ha (324 acres) in 4 clearcuts• 7.6 mmbf and 2,059 loads of logs
Watershed Hydrology
H A R V E S T I N G E F F E C T S
LOCALMONTHLYSTREAM FLOW
H A R V E S T I N G E F F E C T S
LOCALPEAK FLOW
HARVESTING EFFECTS
DOWNSTREAMPEAK FLOW
QUICK FLOW
MONTHLY STREAMFLOW
August Low Flow SFH
Source: Surfleet & Skaugset. (In press). WJAF
Sediment Yield
Sediment Yield Increases
• Sediment yield results are not consistent with the seminal results in the literature.
• Increases in sediment yield are consistent with and are correlated with increases in water yield.
• This requires further work to separate increases in sediment yield due to increases in stream power from increases due to an increase in the erosion rate of the watershed.
Stream Temperature
The net impact of the timber harvest on the non‐fish‐bearing streams was a 0.5°C decrease in average daily temperature.
Maximum Daily Temperature
DeMersseman Creek (C)6 8 10 12 14 16
Beeb
e C
reek
(C)
6
8
10
12
14
16
18
202002200320042005 First harvest2006200720082009 Dam-break flood
Maximum Daily Temperature
DeMersseman (C)6 8 10 12 14 16
Beeb
e 30
0m (C
)
6
8
10
12
14
16
18
20
2002200320042005 First harvest2006 200720082009
Maximum Daily Temperature
C05 (C)6 8 10 12 14 16 18
T05
(C)
6
8
10
12
14
16
18
20
2002200320042005 First harvest2006 200720082009 Second harvest
Maximum Daily Temperature
C01 (C)6 8 10 12 14 16 18 20 22
T04
(C)
8
10
12
14
16
18
20
20022006 200720082009 Second harvest
Maximum Daily Temperature
North Fork (C)6 8 10 12 14 16 18 20 22
Sout
h Fo
rk (C
)
8
10
12
14
16
18
20
2002200320042005 First harvest2006 20082009 Second harvest
• Fertilizer was applied to both watersheds in the fall of 2004
• Existing clearcuts and imminent clearcuts did not receive fertilizer
• The North Fork received 25% more fertilizer per hectare
• Fish-bearing streams: 60 foot buffer strips
• Non-fish-bearing streams: no protection
• Fenton received no fertilizer
Nitrate response
• Strong seasonal fluctuation during the calibration period• Muted seasonal response during the first post-treatment period• More pronounced seasonal response during the second post-treatment
period
Nitrate response
Calibration Period 1 Period 2North Fork 0.015 0.017 0.023South Fork 0.098 0.075 0.117Treatment headwaters 0.129 0.207 0.135
Mean NO3 + NO2 (mg/L)
Amphibians
DataCollection• Sampled only
before and after the first entry.
• Sampled 100 sites/yr.
• Average of 39 were unoccupied.
Amphibian Results
Effect of Being Within a Harvest Unit
0.00
1.00
2.00
3.00
4.00
5.00
2004 2005 2006 2007Odd
s Ratio (and
Con
fiden
ce Lim
its)
Aquatic Invertebrates
2004
2006 - 2009headwaterlogging
25
30
35
40
45
50
55
2004 2005 2006 2007 2008 2009
controltreatment
Benthic taxa richne
ss2004 2005 2006 2007 2008 2009
controltreatment
1
10
100
Benthic pe
rcen
tchiro
nomids
Invertebrate Response in Headwaters:Percent Chironomids, Increased,
Taxa Richness Decreased
Tributaries with Fish:No downstream effects on invertebrates
after harvest in headwatersafter harvest in headwaters
300
3000
30000
2004 2005 2006 2007 2008 2009
control
treatment
Benthic inverteb
rates p
er squ
are meter
Benthic densities (in this graph), percent chironomids and taxa richness did not differ significantly from controls
Same relationships for Age-1+ CT with 1-yr lag in both watersheds
Dissimilar relationships for Age-0 CT (no lag) between
watersheds
At this point in time, what do we think we have learned at Hinkle Creek?
• For almost every discipline, contemporary forest practices resulted in detectable changes in a parameter of interest.
• These changes were often difficult to detect, not acute, often subtle, and the magnitude of the changes existed well within the spatial variability exhibited within the watershed.
Douglas County Thank You!
Invertebrate Response in Headwaters:
Densities Increased
headwaterlogging
300
3000
30000
2004 2005 2006 2007 2008 2009
control
treatmentBe
nthic inverteb
rates p
er squ
are meter
2004
2006 - 2009
Annual stream export
• Probably a 16-fold increase in annual stream export
• A portion of this increase is due to fertilizer
• Average input of nitrate from precipitation is approximately 0.7 kg/ha/yr