Transitions in Rangeland Evaluations

David A. Pyke & Jeffrey E. Herrick

Jornada Experimental

Range

Forest and Rangeland Ecosystem Science Center

Rangeland Evaluations:• Age of Discovery - 1800’s to 1930

– Rangeland Uses & Abuses– Observations

• Age of Inventory - 1930’s to 1970’s– Described Vegetation, Production, Soils– Taylor Grazing Act - Adjustments of AUM’s

• Age of Planning & Management - 1970’s to 1990’s– Condition & Trend– Broader Objectives

• Age of Sustainability - 2000 to ????

1905

Age of DiscoveryWhat is the West? How can we use it?

• Settlers expected consistent moisture– Powell warned of the

harsh environment

• Livestock successful use

• Livestock overuse observed by federal officials

Powell

Pinchot

Succession & Indicators

• Clements & Sampson• Plant communities

change with grazing– Grazing sensitive or

preferred species are reduced

– Grazing tolerant and non-preferred increase

• Basis of Clements 1920 book on indicators

Grazing Indicators

• Observations from -– Smith, Bentley, Griffiths,

Sampson, Jardine, Wooton & Sarvis

• Certain species within communities are indicators of grazing abuse.

1959

Age of Inventory

• Dust Bowl leads to Taylor Grazing Act – Required inventories of the amount of forage

available for livestock

• Stoddart introduces rangeland condition classes

• Dyksterhuis relates Clementsian succession to condition classes

• Rangeland Classification– Dyksterhuis

• Proposes range site concept

– Daubenmire• Habitat types

Monitoring Techniques Begin

• BLM – Deming 2-phase

• Combination qualitative and quantitative (plot)data

• USFS– Parker 3-step

• 100 points on transect with loop frequency/cover

K. W. Parker

Monitoring Focus

• Vegetation tends to dominate over soils– SCS still maintains soil-vegetation

emphasis

• Forage plants & undesirable plants are indicators of rangeland status

• Upland communities are the focus– Lands around water sources tend to be

sacrificed

• Wildlife habitat needs are secondary to livestock needs

1978

Heady 1975Rangeland Mgmt.

Stoddart, Smith & Box. 1975. Range Management

Congressional Directions

• Forest & Rangeland Renewable Resources Planning Act of 1974– USFS Habitat types were mapped

• Federal Land Policy & Management Act of 1976– BLM Soil Vegetation Inventory Method

(SVIM)• Soil & Water Resources Conservation

Act of 1977– National Resources Inventory (NRI)

Inventory Condition & Trend

• All agencies used some form of Dyksterhuis’ Condition Ratings

• Monitored trend using various techniques– Biomass or cover

• Theory behind cond. & trend was still Clementsian succession

Utilization becomes Important

• Measure of the percent production consumed– Direct via biomass– Indirect via height:weight

• Done on a species-basis• Difficult to determine utilization of

pastures– Estimated by ocular estimate maps

Key Species

0102030405060708090

100

Feb Apr Jun Aug

Uti

liza

tion

(%

)

Spp A Spp B Spp C • Utilization by species lead to key species being monitored.– Selected up to four

species– Utilization consistent

over season– Sufficient abundance and

palatability for livestock– Should make up the

majority of forage

Weakness of Key Species Concept

• Less abundant, highly palatable species are sacrificed– Rangelands recovering from excessive

livestock grazing in the early 1900’s :• Former dominant, but palatable species would

be rare• Some dominant or co-dominant palatable

species might have been sacrificed.• Possible example - Basin Wildrye

Introduction of New Ecological Concepts

• Biological Diversity– Species richness, evenness– Diversity among communities

• Non-equilibrium ecosystem dynamics– State & transition successional models– Thresholds of community change

• Riparian and wetland communities as integral parts of rangelands

• Ecosystem processes– Nutrient & water cycles, energy flow

Influential Documents in Changing Rangeland

Evaluations

2004

Age of Sustainability???

• West 2003 - Risk Assessment, Sustainability, Desertification

• Evaluations not focused on single use• Evaluations strive to incorporate

multiple scales• Upland & Riparian ecosystems often

given equal weight in evaluations

Upland Evaluations & Community Dynamics

Threshold

Reference StateShrub - Annual

Grass State

Annual GrassState

Evaluations of Ecosystem Processes

• Interpreting Indicators of Rangeland Health– 3 Attributes (Site Stability, Hydrologic Function, Biotic Integrity;

17 indicators with some overlapping– Qualitative with Quantitative methods proposed & being tested

• Landscape & Ecosystem Analysis (Tongway et al)– 3 indices (Stability, Infiltration, Nutrient cycling); Multiple

indicators)– Quantitative methods published

Soil/SiteStability

HydrologicFunction

BioticIntegrity

Riparian, Wetland & Aquatic

• Water quality measures• Stream Geomorphic

Classifications• Stream Cross sections• Veg. Classification based on

soil and water table depth.• Greenline techniques• Proper functioning condition• Wetland & stream

invertebrates

Bear Cr. 1977 Season long use

Bear Cr. 1987 Winter use

National/Regional Assessments

• Sustainable Rangeland Roundtable– 5 criteria; measured

indicators/criteria– Ecological, Social &

Economic

• Heinz Center – 10 national & 14 grassland

& shrubland indicators– Many indicators not

populated

• NRI– Rangeland NRI begun in

2003– Non-federal lands

National Resources Inventory

SustainableRangelandsRoundtable

Remote Sensing & GIS

• Combine soil, climate and current vegetation– Large areas– Allows for use of

predictive models• Invasion risk• Erosion potential

• Useful for wildlife habitat assessments– Multiple scales

Wisdom et al. 2003

Landscapes:Patterns, Processes, Resistance &

Resilience• Linkages across

multiple scales• Fragmentation

monitoring• Prediction early ID

of threats and drivers

• Interactions among multiple threats

Future Evaluations: Carbon?

• Carbon Credits on Rangelands– What could be

included– How to measure?

• International politics may dictate the need