Forest Practices and Stream Fishes

1
Forest Practices and Stream Fishes

• 2) Effects of management
• Temperature
• Sediment
• Woody Debris
• Flow regime

• Physical Activities of Forest Management
• i. Roads
• ii. Harvest
• iii. Yarding

• 3) Consequences for Fish
• Community
• Population
• Individual

2
Physical Activities of Forestry

• Build roads
• Cut down trees
• Yard the trees away
• Fertilizers
• Herbicides/pesticides

3
Forest Management in Washington
Source DNR 2001 Timber Harvest Report
4
Effects of Forest Management

• Temperature
• Clear cutting elevates air temperature
• Loss of riparian shade
• Reduced stream depth from sedimentation

Clearcut Sierra Nevada
Seed tree Idaho
5
Effects of Forest Management
Comparison of control and clearcut on adjacent
streams
Summer
Winter
Ecological Monographs 40
6
Effects of Forest Management

• Sedimentation Increased levels of fine material
• Erosion from road surfaces
• Loss of bank stability from riparian zone cuts
• Mass wasting (landslides)

(Cederholm 1982)
7
Effects of Forest Management

• Woody Debris
• Splash dams early practice of removing debris to
  transport logs
• Stump removal thinking it blocked fish passage
• Now known that LOD recruitment is needed

Splash dam
8
Effects of Forest Management
9
Effects of Forest Management

• Hydrologic cycle
• Tree harvest tends to increase variation of flow
  due to vegetation loss.
• Rain-on-Snow flood events snow evaporates from
  trees but accumulates in clearcuts.

Clearcut
Roads
Roads and Clearcut
10
How do we assess the consequences of Forest
Managements physical effects?

• Approaches
• Controlled Lab Studies
• cheap, quick, convincing. Relevant?
• Field Studies
• costly, protracted, realistic. Convincing?
• Models
• cheap, quick. Realistic? Convincing?

11
Consequences of altered thermal regimes for
salmon

• Elevated temperatures accelerate embryo
  development, resulting in earlier emergence

Elevated temperatures can accelerate growth if
food is sufficient, resulting in larger parr,
higher survival, and younger smolts
12
Consequences for salmonCarnation Creek
5000
First logging effects
Age 1
4000
Numbers of coho salmon smolts
3000
2000
1000
Age 2
0
1970 1975 1980 1985
1990 1995
Year
Logging was associated with improved growth, and
a shift from age-2 to primarily age-1 coho salmon
smolts in Carnation Creek.
13
Consequences of fine sediment for salmon
Steven Schroder

• Sediment
• Incubating eggs
• Survival decreases as fines increase
  reduction of dissolved oxygen delivery
• Insect production
• Fine sediment can reduce insect production,
  resulting in poorer growth

Coho salmon egg trough experiments on survival
from egg deposition to emergence (Cederholm and
Salo 1979)
14
Sediment consequences for salmon
Egg to fry survival for chum and coho salmon in
Carnation Creek.
15
Consequences for Fish

• Hydrology
• Overall, most salmonids die in the egg-fry period
  (50-90)

Atsushi Sakurai
16
Carnation Creek Coho salmon
High winter flows reduce the survival of salmon
embryos in the gravel
Sockeye salmon
17
Consequences for Fish

• Woody Debris
• Provides cover in the summer
• Provides refuge in winter and shapes the stream
• Traps finer organic material, enhancing primary
  production

Snohomish River
18
Logging practices have complex effects on key
physical features of streams (temperature,
sediment, flow and woody debris). These effects
may magnify or offset each other in overall
consequences for fishes, so what is the overall
consequence for fish populations? How do we
measure the consequence, and over what time frame?
19
Consequences for salmonCarnation Creek
Tschaplinski 2000
20
Consequences for salmonCarnation Creek
Tschaplinski 2000
21
Consequences for salmon in Carnation Creek
22
What factors facilitate detection of change (good
or bad)?

• Less variation in the data
• Longer period of record
• Greater absolute change

23
Mean 25, SD 4.2
Mean 15, SD 2.6
24
Mean 25, SD 4.2
Mean 15, SD 2.5
?
25
Mean 25, SD 8.7
Mean 15, SD 6.8
26
Assessing Consequences for Fish

• Parameter Selection and Sample Sizes in Studies
  of Anadromous Salmonids
• Natural variation was examined for several
  important parameters of anadromous salmonid
  populations. Survival and abundance showed low
  statistical sensitivity to detect change
  Studies of survival and abundance may require
  20-30 years of produce and 80 chance of
  detecting a 50 change, while studies of time and
  size at important life history stages should
  require 8 to 10 years to provide and 80 chance
  of detecting a 5 to 15 change
• Lichatowich and Cramer ODFW (1979)