The Grazing Response Index

A Simple and Effective Method to Evaluate Grazing Management

Shane Green NRCSWith many slides borrowed from Dave Bradford, USFS

ret.

GRI History

Developed by CSU Extension (Roy Roath)

Early implementation by USFS (Dave Bradford, Floyd Reed)

1999 Rangelands Article

GRI in Agency Technical References

Grazing Response Index

The GRI is used to assess the effects of grazing during the growing season, using the following criteria:

Frequency (measured by Duration) of grazing.

Intensity of grazing.

Opportunity for growth before grazing OR re-growth following grazing.

Frequency

The number of times a plant is defoliated during active growth.

Normally figure one defoliation every 7 days, during active growth.

As growth slows down figure one defoliation every 10 days, or longer depending on actual growth periods.

One defoliation is positive and rates +1

Two defoliations is neutral and rates 0

Three or more defoliations is negative and rates -1

Intensity

The amount of leaf material removed during the grazing period. The key point being the amount of leaf material left for the plant to continue photosynthesis.

Light defoliation (> 65% leaf material remaining) +1

Moderate (50-64% leaf material remaining) 0

Heavy defoliation (< 50% leaf material remaining) -1

Generally a grazing intensity of <50% of leaf material removed allows the plant to meet it’s needs and continue growth.

Opportunity

For plant growth and/or regrowth .

This criteria carries double the value of the frequency and intensity criteria.

Full season to grow/regrow +2

Most of season +1

Some chance 0

Little chance -1

No chance -2

This incorporates Time and Duration of grazing.

What Does the GRI Do? The values are additive, providing a

positive, neutral, or negative rating for assessing the grazing impacts for the year.

This gives you an assessment of how your grazing strategy worked this year.

Provides a basis for planning next year’s grazing use.

Accounts for more than just utilization to assess grazing effects

What the GRI does not do

Monitor or assess rangeland plant communities or processes

Replacement for vegetation monitoring and assessment

Graphic

Assessment Monitoring

Gra

zing

Pla

nts

Eco

logic

al

Pro

cess

es Interpreting

Indicators of Rangeland

Health

Trend Photo Plots,

Cover, Nested Frequency,Species composition

Multiple Indicator Monitoring

MIM

ApparentTrend

Grazing Response Index GRI

Proper FunctioningCondition

PFC

Utilization

Similarity Index(Range Condition)

RemoteSensing

SVAPWeather

and Climate

Soil Survey

Where does GRI fit in to our work?

Stock and monitor approach Lots of tools to monitor the land and

plants Lack tools to evaluate grazing – GRI

helps to fill this void.

Example 1:

The first example shows the Oak Ridge (BLM) allotment (left side of fence) and the West Elk (FS) allotment (right side of fence).

Both allotments are managed with multi-pasture grazing strategies.

Oak Ridge is grazed by 305 cow/calf pairs, owned by 2 permittees, from 5/10-6/15, with 10 pastures.

West Elk is grazed by 1250 cow/calf pairs, owned by 7 permittees, from 5/15-10/10, with 30 pastures.

Oak Ridge (BLM)/West Elk (FS) Prior to grazing

5-13-1999

Oak Ridge (L)/ West Elk (R), 6-4-99Grazed 5/21-5/26/1999 / Ungrazed

Oak Ridge (L)/ West Elk (R), 7-9-99

45 days post-grazing / Ungrazed

Oak Ridge (L)/ West Elk (R), 9-9-99

105 days post-grazing / Ungrazed

Oak Ridge (L)/West Elk (R),10-20-99

145 days post-grazing / Grazed 9/20-10/10

How Would the GRI Rate This ?

1999Oak Ridge Frequency +1 Intensity 0 Opportunity +1 Total Response +2West Elk Frequency 0 Intensity 0 Opportunity +2 Total Response +2

Do these Grazing Responses relate to Range Trend?

Oak RidgeOak RidgeWest ElkWest Elk

7-23-917-23-91

Oak Ridge (L)/West Elk (R),

7-23-1991 8-10-2001

Example 3:

This example shows Bear Trap Park on the Dyer allotment.

This example is based on historic photo monitoring, looking at three years 1948, 2000 and 2001.

Dyer C&H Bear Trap Park 10/15/1948 Allotment grazed season-long, 5/16-10/15, by 1,048 cow/calf pairs for 5,240 AUMs. SR – 3.0 acres/AUM. Precipitation for season was 105%.

10/12/2000 Allotment grazed multi-pasture rotation, 6/16-10/10, by 425 cow/calf pairs for 2,150 AUMs. This pasture grazed 8/11-10/05 in 2000. SR – 5.8 acres/AUM. Precipitation for season was 80%.

Dyer C&H Bear Trap Park 10/15/1948 Allotment grazed season-long, 5/16-10/15, by 1048 cow/calf pairs for 5,240 AUMs. SR – 3.0 acres/AUM. Precipitation for season was 105%.

10/15/2001 Allotment grazed multi-pasture rotation, 6/16-10/10, by 375 cow/calf pairs for 2,150 AUMs. This pasture rested in 2001. SR – 5.8 acres/AUM. Precipitation for season was 89%.

How Would the GRI Rate This ?

Dyer Allotment 1948 2000 2001

Frequency -1 -1 +1

Intensity -1 -1 +1

Opportunity -2 +1 +2

Total Grazing Response

-4 -1 +4

Example 4:

This example shows Corral Creek on the Corral Gulch Pasture on the Mesa allotment.

This allotment is managed using a multi-pasture grazing strategy.

The allotment is grazed by 2,000 cow-calf pairs/yearlings, 6/26-10/20.

The Black Mesa Story

Corral Gulch 9/1/1992

Corral Gulch 9/1/1992

Mesa C&H Lower Mesa Unit 8/12/1991

Mesa C&H Upper Mesa Unit 8/2/1991 35% Use

How Would the GRI Rate This ?

Mesa Allotment Corral Gulch Pasture

1995 2007

Frequency 0 0 Intensity 0 0 Opportunity +1 +1 Total Grazing Response +1 +1

Summary of Grazing Response Values on Corral Gulch Pasture of Mesa C&H Allotment, 1995-2007

95 96 97 98 99 00 01 02 03 04 05 06 07

F 0 0 0 +1

0 +1

-1 0 0 0 0 -1 0

I 0 0 0 0 -1 0 -1 +1

0 0 0 +1

0

O +1

+1

+1

+1

+1

-1 +1

-1 0 +1

+1

+1

+1

T +1

+1

+1

+2

0 0 -1 0 0 +1

+1

+1

+1

Summary of Grazing Response Values on Corral Gulch Pasture of Mesa C&H Allotment, 1995-

2007: Positive values 8 of 13 years (62%). Neutral values 4 of 13 years (31%). Negative values 1 of 13 years (7%).

Grazing Responses can and do relate to long-term vegetative trend.

Mesa C&H Corral Gulch 9-25-1995 Grazed 7/25-8/08 (15 days) by1,782 cow/calf pairs & 155 yearlings. 313 mm Growing season precipitation or 169%.

10-10-2007 Grazed 7/15-7/29 (15 days) by1,883 cow/calf

pairs 104 yearlings. 215mm Growing season precipitation or 116%.

Mesa C&H Corral Gulch 9-25-1995 Grazed 7/25-8/08 (15 days) by1,782 cow/calf pairs & 155 yearlings. 313 mm Growing season precipitation or 169%.

10-10-2007 Grazed 7/15-7/29 (15 days) by1,883 cow/calf

pairs 104 yearlings. 215mm Growing season precipitation or 116%.

Dry Fork C&H Allotment ExampleoAllotment consists of 31,000 acres of which 16,000 are considered unsuitable to grazing.

oThe allotment is grazed by up to 630 cattle owned by 5 different permittees.

oThe allotment has nine pastures, that are grazed from 3 to 32 days.

oCattle graze the Deer Creek/Apache pasture first every year; graze the Sherwood pasture every other year and graze the Ditch pasture last every year.

Summary of GRI Values on Apache Rocks – Deer Creek Pasture of Dry Fork C& H Allotment, 1998-

200998

99

00

01

02

03

04

05

06

07

08

09

F -1 No Data

0 0 No Data

-1 0 Pasture rested

No Data

-1 0 0

I -1 0 0 0 -1 -1 0 -1

O 0 +1

+2

-1 -1 +1

+1

0

T -2 +1

+2

-2 -2 -1 +1

-1

Summary of Grazing Response Values on Apache Rocks-Deer Creek Pasture of Dry Fork C&H

Allotment, 1998-2009:(Data available for 8 of 12 years)

Positive values 3 of 8 years (38%). Neutral values 0 of 8 (0%). Negative values 5 of 8 years (62%).

Grazing Responses can and do relate to long-term vegetative trend.

Dry Fork C&HDeer Creek PastureDeer Creek CM West View6/18/199914 plant species40% smooth brome30% Kentucky bluegrassTrace wheatgrassTrend uncertain.Dry Fork C&HDeer Creek PastureDeer Creek CM West View6/15/200921 plant species80% smooth brome5% Kentucky bluegrassTrace wheatgrass &Baltic rushTrend slightly upward.

Summary of GRI Values on Sherwood Pasture of Dry Fork C& H Allotment, 1998-2009

98

99

00

01

02

03

04

05

06

07

08

09

F Pasture rested

No Data

Pasture rested

+1

Pasture rested

+1

Pasture rested

0 Pasture rested

0 Pasture rested

+1

I 0 0 0 0+1

O +2

+1

0 +1

+1

T +3

+2

+2

0 +2

Summary of Grazing Response Values on Sherwood Pasture of Dry Fork C&H Allotment, 1998-2009:

(Data available for 11 of 12 years)

Positive values 4 of 6 years pasture was grazed (67%).

Neutral value 1 of 6 years pasture was grazed (17%).

Negative values 0 of 8 years (0%). No data 1 of 8 years pasture was grazed

(16%) Pasture rested 6 of 12 years (50%).

Dry Fork C&HSherwood PastureElijah’s Park CM East View6/18/199922 plant species35% Kentucky bluegrass20%western wheatgrassTrace Letterman needlegrassTrend estimated upward.Dry Fork C&HSherwood PastureElijah’s Park CM East View6/18/200929 plant species25% Kentucky bluegrass5% western wheatgrass5% Letterman needlegrassTrend upward.

Dry Fork C&HSherwood PastureElijah’s Park CM East View6/18/2009

Pasture grazed from 7/6-18/2009 by ~500 head of cattle.Dry Fork C&HSherwood PastureElijah’s Park CM East View10/07/2009GRI RatingF = +1 (13 days)I = 0 (moderate)O = +1 (most of season)TGRI = +2

Summary of GRI Values on Ditch Pasture of Dry Fork C& H Allotment,

1998-200998

99

00

01

02

03

04

05

06

07

08

09

F +1

No Data

+1

0 No Data

+1

0 +1

+1

-1 No Data

+1

I 0 -1 -1 +1

+1

+1

+1

-1 +1

O -1 +1

+1

+2

+2

+2

-2 -2 -1

T 0 +1

0 +4

+3

+4

0 -1 +1

Summary of Grazing Response Values on Ditch Pasture of Dry Fork

C&H Allotment, 1998-2009:(Data available for 9 of 12 years)

Positive values 5 of 9 years (55%). Neutral values 3 of 9 (33%). Negative values 1 of 8 years (12%).

Dry Fork C&HDitch PastureUpper Poison Gulch CM NE view6/18/199922 plant species30% smooth brome70% Kentucky bluegrassTrace Columbia needlegrassTrend estimated upward.Dry Fork C&HDitch PastureUpper Poison Gulch CM NE view7/23/200938 plant species30% smooth brome40% Kentucky bluegrass7% Columbia needlegrassTrend upward.

Grazing Response Index - Summary:

The GRI is used to assess grazing management using the following 3 criteria:

Frequency (measured by duration) - The number of times a plant is defoliated during active growth.

Intensity - The amount of leaf material removed during the grazing period. The key point being the amount of leaf material left for the plant to continue photosynthesis.

Opportunity For plant growth before grazing and/or re-growth following grazing.

Summary, continued: Easy to understand and communicate.

Allows specialists summarize and communicate a more comprehensive picture of grazing management effects

Fills a void in the landscape of monitoring and evaluation tools with a focus on the management rather than the resource.

Considers more than just utilization Incorporates stock density, time and

duration of grazing, and plant growth and re-growth.

Summary, continued:

Provides a basis for adjusting grazing in subsequent years.

GRI evaluations should correlate to long-term trend monitoring.

Where to take GRI from here

Proposed refinements Geographic fine tuning Adding an evaluation factor for

physiological stage of plant growth when grazed

Agency collaboration and endorsement Need for an update and published

interagency technical reference, akin to the Interpreting Indicators of Rangeland Health or Creeks and Communities efforts.

Are There Any

Questions ?