tradeoffs between vegetation management and …...collected every 5 minutes over a 13-day period in...

Special Thanks to Present and Past Stakeholders! Affiliation Name Crow Valley Livestock Cooperative Steve Anderson, Leonard Ball, Dana

Bowman, Jason Kern, Andy Lawrence, Scott Timm

The Nature Conservancy Terri Schulz, William Burnidge Bird Conservancy of the Rockies Seth Gallagher, Angela Dwyer Environmental Defense Fund Ted Toombs Colorado State University Extn Casey Matney USDA - NRCS Rachel Murph USDA - FS Kim Obele CO State Land Board Matt Pollart We thank Nick Dufek, David Smith, Jeff Thomas, Pam Freeman, Matt Mortenson, Jake Thomas, Craig Lawrence, Melissa Johnston, and the many ARS and CSU field technicians that made this experiment possible, and CVLC for providing the cattle.

Example of cattle foraging behavior in the AGM herd (red circles) versus a paired TGM herd (yellow circles). The example shows GPS collar fixes for 1 steer in each treatment collected every 5 minutes over a 13-day period in 2014. AGM cattle grazed in more linear pathways, moved longer distances while grazing, and spent less time per day engaged in grazing behaviors.

Tradeoffs between Vegetation Management and Livestock Production under Adaptive Grazing Management

David J. Augustine1, Justin D. Derner1, Maria E. Fernandez-Gimenez2, David D. Briske3, Hailey Wilmer1, Lauren M. Porensky1, Kenneth W. Tate4, Leslie M. Roche4

1USDA-Agricultural Research Service, Rangeland Resources Research Unit, Fort Collins, CO 80256 / Cheyenne, WY 82009, 2Department of Forestry and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80253, 3Ecosystem Science and Management Department,

Texas A&M University, College Station, TX 77843, 4Department of Plant Sciences, University of California-Davis, Davis, CA 95616 *Correspondence: David.Augustine@ars.usda.gov

Grazing Plan Implementation In 2014, cattle were moved among pastures when one of three triggers – residual forage biomass, cattle behavior, or maximum number of grazing days - was achieved in the currently grazed pasture.

In 2015, the maximum days threshold was removed such that moves among pastures were only based on forage biomass and cattle behavior.

Due to 2 consecutive years of above-average spring precipitation and forage production rates, the AGM herd grazed 7 of 10 pastures in 2014 and 4 of 10 pastures in 2015. Thus, a substantial portion of the landscape under adaptive grazing management was rested in 2014 and/or 2015.

Rested

Rested

Sept 9 August 8

Rested

May 16

May 30 July 23

June 20

July 8

2014(214 steers)

Aug 20

July 7

Rested Rested

Rested

Rested

May 30 May 27

Rested

Rested

2015(224 steers)

0

50

100

150

200

250

300

350

400

450

500

2013 2014 2015

Annual Precipitation (mm)

Long-termMean

Vegetation Responses

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

AGM TGM

RATE

OF

INCR

EASE

, 201

3 -2

015

Pastures Rested in 2014

0

0.5

1

1.5

2

2.5

3

3.5

AGM TGM

RATE

OF

INCR

EASE

, 201

3 -2

015

All Pastures

Res

idua

l For

age

Bio

mas

s (k

g/ha

)

400

600

800

1000

1200

1400

1600

AGM TGM0

500

1000

1500

2000

2500

3000

Residual Biomass after Grazing Season

0

100

200

300

400

500

600

2013 2014 2015

ANPP

(kg

ha-1

)

AGM

TGM

Aboveground Production by C3 Perennial Gramminoids

Rate of Increase in Western Wheatgrass

Tiller Density

Conclusions

Managing cattle as a single large herd rotated among many pastures instead of many small herds distributed evenly among pastures resulted in an economically significant loss in livestock weight gains (15-16% over 2 above-average precipitation years).

Large reductions in weight gain occurred in spite of adaptive selection of pasture sequences based on temporal patterns of forage production and availability (i.e. initiating grazing season in C3-dominated pastures, followed by rotation to C4-dominated pastures later in grazing season).

Reduced livestock gains with increased stock density are consistent with measured changes in diet selection and animal foraging behavior. High-stock-density steers foraged in more linear pathways and consumed diets with reduced crude protein content throughout both growing seasons, as compared to low-stock-density steers.

Reduced diet quality occurred during the first week after steers were rotated into a new pasture. These results indicate a strong effect of herd size, regardless of how quickly animals move among pastures.

Benefits of resting pastures for a full growing season were not readily measureable after 2 years of treatments. One C3 perennial grass increased in density 44% more rapidly in rested compared to moderately grazed pastures, but this species increased in both treatments. We have not yet detected an increase in C3 gramminoids production.

A unresolved question is whether future enhancements in forage production and residual biomass due to AGM could enhance livestock production during drought.

Literature Cited

Fuhlendorf, S.D., D.M. Engle, R.D. Elmore, R.F. Limb, and T.G. Bidwell. 2012. Conservation of pattern and process: Developing an alternative paradigm of rangeland management. Rangeland Ecology and Management 65, 579-589. Kachergis, E., J.D. Derrner, B.B. Cutts, L.M. Roche, V.T. Eviner, M.N. Lubell, and K.W. Tate. 2014. Increasing flexibility in rangeland management during drought. Ecosphere 5, 1-14.

The Adaptive Grazing Management Experiment

In 2012, we initiated an adaptive grazing management experiment in the shortgrass steppe of northeastern Colorado, USA, where 11 stakeholders representing ranchers, state and federal land management agencies, and non-governmental conservation organizations met to develop and implement an adaptive grazing management plan for ten 130-ha pastures. Stakeholder Group members determined: 1) Overall management goals, and specific objectives

related to each goal. 2) Grazing management strategies that would be

implemented to achieve the objectives 3) Types of monitoring data to inform adaptive

management 4) Triggers for cattle movement among pastures

• Cattle in the Traditional Grazing Management (TGM) treatment are distributed evenly among 10 pastures, and graze them continuously during May – Oct.

• Cattle in the Adaptive Grazing Management (AGM) treatment are managed as a single herd rotated among pastures, with the objective of grazing 8 of 10 pastures (and resting the remaining 2 pastures) given average precipitation, and adjusting this grazing plan in response to intrannual precipitation variability.

• AGM and TGM pastures have the same overall stocking rate, but stock density is 10-fold greater in the AGM treatment.

Cattle Responses

Date

May 23

May 30

June

6Ju

ne 13

June

20Ju

ne 27

July

3Ju

ly 8

July

15Ju

ly 23

July

29Au

g 5Au

g 12

Aug 1

8Au

g 26

Sept

2Se

pt 8

Sept

23Se

pt 29

Crud

e Pr

otein

in D

iet

4

6

8

10

12

14

16

AGM HerdPaired TGM Herd

May 23

May 30

June

6Ju

ne 13

June

20Ju

ne 27

July

3Ju

ly 8

July

15Ju

ly 23

July

29Au

g 5Au

g 12

Aug 1

8Au

g 26

Sept

2Se

pt 8

Sept

23Se

pt 29

Dige

stibl

e O

rgan

ic M

atte

r in

Diet

54

56

58

60

62

64

66

68

70July 15July 23July 27Aug 5Aug 12Aug 19N.a.N.Aug 27Sept 3Sept 11Sept 18Sept 25

Crud

e Pr

otein

in D

iet

4

5

6

7

8

9

10

11

12

AGM HerdPaired TGM Herd

July

15Ju

ly 23

July

27

Aug 5

Aug 1

2Au

g 19

N.a.N

.Au

g 27

Sept

3Se

pt 11

Sept

18Se

pt 25

Dige

stibl

e O

rgan

ic M

atte

r in

Diet

58

59

60

61

62

63

64

2014: 2-4 week rotations 2015: 5-6 week rotations

AGM TGMPercent time foraging (grazing fixes/total fixes) 35.1 51.7Mean foraging angle (degrees per 5 min) 146.3 134.8Mean foraging distance (meters per 5 min) 43.6 40.9

AGM Website:

Introduction Rangelands are characterized by temporal variability in weather overlaid on spatial topoedaphic variability (Fuhlendorf et al. 2012). In semiarid rangelands in particular, droughts create major financial hardship for livestock producers around the world. Strategies for coping with drought include reducing livestock numbers, leasing forage, temporarily grazing rangeland beyond its capacity, and increasing supplemental feed, but these involve economic or ecological costs. Alternative approaches to increase enterprise flexibility in responding to drought are clearly needed (Kachergis et al. 2014). Managing the spatial distribution of livestock during wet periods in order to enhance future production potential could improve ranch- scale resilience during droughts, but has not been evaluated at scales relevant to livestock producers.

Selected Goals:

Red Circles: AGM steer foraging locations Yellow Circles: TGM steer foraging locations Black crosses = Bedding, standing, travelling

2014

2015

P=0.10

P=0.81

P=0.64