Not “tree cover,” but instream physical structure

Instream Cover or Stucture

Cover

Max 20

2]I NSTREAM COVER(Structure)

(Give each cover type a score of 0 to 3; see back for instructions) AMOUNT: (Check ONLY One orTYPE: Score All That Occur check 2 and AVERAGE )

___UNDERCUT BANKS [1] ___POOLS>70 cm [2] ___OXBOWS, BACKWATERS [1] - EXTENSIVE >75%[11]___OVERHANGING VEGETATION [1] ___ROOTWADS [1] ___AQUATIC MACROPHYTES[1] - MODERATE 25-75%[7]___SHALLOWS(IN SLOW WATER) [1] ___BOULDERS [1] ___LOGS OR WOODY DEBRIS [1] - SPARSE 5-25% [3]___ROOTMATS [1] COMMENTS:______________________________________________ - NEARLY ABSENT <5%[1]3] CHANNEL MORPHOLOGY: (Check ONLY One PER Category OR check 2 andAVERAGE )

Previous threshold for check box for a given cover type was low (~5%)

Overall cover metric and number of cover types correlated with IBI, but individual cover type quality not rated well

Each cover type scored from 0-3 points based on standard definition

Still scoring based on old method also, will phase out next year; need to calibrate new method to old data

Newer Cover Scoring Procedure

Instructions for scoring the alternate cover metric: Each cover type should receive a score of between 0 and 3, Where:

0 - Cover type absent; 1 - Cover type present in very small amounts or if

more common of marginal quality; 2 - Cover type present in moderate amounts, but

not of highest quality or in small amounts of highest quality;

3 - Cover type of highest quality in moderate or greater amounts. Examples of highest quality include very large boulders in deep or fast water, large diameter logs that are stable, well developed rootwads in deep/fast water, or deep, well-defined, functional pools.

New Cover Metric

Amount of Cover

Rootwads/Logs

High Quality Rootwad

Sycamore among the best quality

Large diameter roots

Best when in deep water

Best when in or adjacent to fast water

Aquatic Macrophytes

0

0.2

0.4

0.6

0.8

1

Absent Present Absent Present

Tota

l Pho

spho

rus

Aquatic PlantsOxbows, Backwaters,

Sidechannels

N = 303 N = 106 N = 399N = 10

Only macrophytes, not algae or diatoms

Emergent or submergent Great nursery areas Improve riffle quality by

making riffles narrower and deeper

Boulders Examine all cover

types to determine whether they are functional!

Functional Boulder: In Deep

Fast Water

Non-Functional Boulder: In Shallow Water & Embedded

Undercut Banks Needs to be in deep enough water and undercut enough to

provide function as cover If undercut is part of rootwad count as rootwad, not as undercut

Rootmats Fine fibrous roots

of willows and other plants

Small fish may use these as cover or feed on invertebrates that colonize them

Logs and Woody Debris

Habitat forming functions

Fish cover Macroinvertebrat

e production, especially in big rivers

Bank protection

Overhanging Vegetation

Shading Refuge from avian

predators (e.g., kingfishers, herons)

Terrestrial food Does not include

high canopy

Oxbows, Backwaters, & Side Channels

10

20

30

40

50

60

Absent Present Absent Present

IBI

Aquatic PlantsOxbows, Backwaters,

Sidechannels

N = 317

N = 105N = 431

N = 10

Oxbows, backwaters, and side channels are excellent nursery habitat

Sequester/transform nutrients Spawning areas (e.g., northern pike, muskie)

Oxbow

Backwater

Shallows in Slow Water Y-O-Y fish use margin areas to feed

and escape predators

Cover vs IBI

10

20

30

40

50

60

0-4 5-8 9-12 13-16 17-20

IBI

Cover Metric Score10

20

30

40

50

60

0 5 10 15 20

Data by Site All YearsECBP & HELP EcoregionsReference Sites ONLY

y = 22.08 + 1.44x R2= 0.33

Site

Spe

cific I

BI

Site Specific QHEICover Score

1

10

100

0 1 2 3

Spotted Bass vs Logs and Woody Debris Score

Relat

ive N

umbe

r

Logs and Woody Debris Score (0-3)

Benefits of New Scoring Approach

Spotted Bass

1

10

100

0 1 2 3

Smallmouth Bass vs Boulder Cover

Relat

ive N

umbe

r Boulder Cover Score (0-3)

1

10

100

0 1 2 3

Green Sunfish vs Boulder Cover

Relat

ive N

umbe

r

Boulder Cover Score (0-3)

Habitat Generalist: Green Sunfish