David Feldman. Evaluating Macroinvertebrate Responses To ...

Evaluating
Macroinvertebrate
Community Responses to
Sediment in Mountain
Streams Using
Biometrics
David L. Feldman
Montana Department of
Environmental Quality

Background
Sedimentation easily linked to fisheries
New information linking
macroinvertebrates to sedimentation
(Bryce et al. 2010)
Field Study

DEQ Sediment
Assessments
Western Montana
Uses several parameters:
– Level I
Pebble counts
Pool tail fines
Width:Depth
Pool Quality: Fish spawning habitat
– Level II
Biology (macroinvertebrates and periphyton)

Phase 2
60 stream sites
Western Montana
2011 (30 sites)
– Used TMDL assessments (habitat and
sediment listings)

Parameters
Sediment
–

Expected O/E Response
Increasing

Expected MMI Response
Increasing

Sampling Reach
L
K
R
J
= Pool
= Riffle
C
I
H
L
G
R
= Macroinvertebrate Sampling location
= Pebble Count Transect
= Pool Tail fine grid
F
C
E
L
R
D
C
C
L
B
R
A

Site Locations

Biological Indicators
Observed/Expected
Developed from reference
sites
Directly measures taxa
richness
Quantile Regression
– Heteroscdascity
– Sample size
Multimetric Index
Developed from a variety
of streams
Measures several aspects
of community
– Taxa richness
– Sensitive taxa

Data Analysis
Regression
– Ordinary Least Squares Regression
Quantile Regression (see Cade and Noon
2003; Bryce et al. 2010)
– R statistical software “Quantreg” package
– Inverse Cumulative Distribution Function
– Any real-valued random variable Y has rightcontinuous
cumulative distribution function
F(y) = P(Y ≤ y)
– where for any 0 ≤ ≤ 1,
Qy() = Fy−1() = inf {y: F(y) ≥ }

Biological Example:
Cade and Noon, 2003

Example (continued)

Regression O/E

Quantile Regression O/E

Quantile O/E
Quantile
Quantile

Quantile O/E
Quantile Coefficient Value Lower 95
CI
0.1 Intercept 0.37 0.19 0.53
Slope 0.73 0.06 0.96
0.2 Intercept 0.54 0.38 0.56
Slope 0.44 0.39 0.78
0.3 Intercept 0.55 0.52 0.82
Slope 0.32 -0.34 0.64
0.4 Intercept 0.58 0.53 0.99
Slope 0.50 -0.42 0.83
0.5 Intercept 0.85 0.51 1.07
Slope 0.03 -0.53 1.12
Upper 95
CI

Regression: MMI

Quantile Regression: MMI

Quantile MMI
Quantile Coefficient Value Lower 95
CI
Upper 95
CI
0.1 Intercept 38.78 21.69 47.27
Slope 42.20 18.10 80.11
0.2 Intercept 46.37 35.77 64.86
Slope 38.45 -10.71 58.88
0.3 Intercept 47.47 39.90 70.92
Slope 44.02 -9.81 46.96
0.4 Intercept 61.57 47.38 73.53
Slope 12.47 -25.62 46.67
0.5 Intercept 61.52 49.47 76.88
Slope 14.13 -22.78 40.63

Quantile MMI
Quantile

Patterns
O/E:
– Macroinvertebrate communities reflecting
a good water year (2011)
– Macroinvertebrates responding to the
instream fine sediment levels
O/E and MMI not showing a significant
difference greater than tau=0.3 and 0.1,
respectively
Small dataset affects the statistics
– DEQ will look into other methods/indicators for
sediment
Further analysis (and more data!)needed to
pin down major patterns

Conclusion
The O/E and MMI respond to general
changes in stream quality, not
sediment
We will explore other options

Special Thanks
Montana Natural Heritage Program
– Dave Stagliano
– Steve Fernandes
Ecoanalysts, Inc