STATE & TRANSITION MODELS & DISTURBANCE RESPONSE GROUPS FOR MLRA 24 Tamzen Stringham, Patti Novak-Echenique, Erica Freese, Lucas Wiseley, Patrick Shaver
INTRODUCTION Currently ~18,000 ESD s need written or approved Not including federal lands An ESD is not complete without the ecological dynamics model (STMs) Not enough time, money, or people to complete data-based STMs for all the ESD s
ECOLOGICAL DYNAMICS RESPONSE TO DISTURBANCE Quantitative Climax Model State-and-Transition Model MLRA 24 Loamy 8-10 PZ
Historical Plant Community the basis for the Range Condition Model also known as Quantitative Climax Model Departure from climax or HPC determines range condition Management could influence successional pathway through grazing pressure
Quantitative Climax Model Above-average rainfall Drought Successional tendency VEGETATION Grazing Pressure 0 25 50 75 100 Early successional Poor Condition Condition scale Range Trend Climax Excellent Condition (adapted from Westoby, Walker, Noy-Meir 1989)
The Range Condition Model (Dyksterhuis 1949) based on successional theory developed in the early 20 th century vegetation composition changed linearly in response to climate and grazing pressure vegetation change interpreted in terms of deviation from historic plant community utilized range condition class and similarity index to measure deviation measurement allowed adaptive management A successful demonstration of the application of ecological theory
Quantitative Climax Model Potential to work well in many systems Great Plains Mountain Grasslands Some dynamics in arid and semi-arid systems Many instances where this model does not adequately describe vegetation change
STATES Thresholds Drought Vegetation attribute(s) Grazing Pressure Irreversible Reversible 0 25 50 75 100 Early successional Poor Condition Range Trend Climax Excellent Condition
ECOLOGICAL PROCESS MODEL THE BASICS MINIMUM SCALE FOR STATE = ECOLOGICAL SITE Plant Community Phase State 2 State 1 At-Risk Phase Threshold At-Risk Phase Transition State 3
State-and-Transition Models (Stringham et al.2003) (Briske et al. 2008) Accommodates: Range Succession Model (Quantitative Climax Model) Accounts for transitions, thresholds, and multiple steady states Process based NOT vegetation
State-and-Transition Models Allows for more detail in triggers and pathways of vegetation change Spatial scale: Ecological Site Temporal framework: Current climate Describes ecological dynamics Repository: historical, local & scientific knowledge
ECOLOGICAL PROCESS MODEL THE BASICS MINIMUM SCALE FOR STATE = ECOLOGICAL SITE Plant Community Phase Restoration State B State A At-Risk Phase Threshold At-Risk Phase State C
ECOLOGICAL SITE DESCRIPTIONS NRCS has accepted the STM as the format for describing ecological dynamics for the nation s rangelands Ecological Site descriptions are required to have the ecological dynamics described thru the STM format Range Site descriptions are being updated to include the STM
DISTURBANCE RESPONSE GROUPS KEY CONCEPTS Group of ESD s that respond similarly Rate of response may vary End point is same STM is essentially the same Ecological Dynamics describes differences
DEVELOPMENT PROCESS MLRA 24-Nevada 54 ESD s (Range Sites) ~7 million acres Assemble MLRA 24 Experts NRCS, BLM, Consultants, Academic Observational Knowledge Office Meeting(s) 24
DISTURBANCE RESPONSE GROUP DEVELOPMENT Dominant Vegetation Soils: Depth, Texture, Parent Material, Diagnostic Horizons, Chemical Characteristics, Temperature Precipitation Slope and Elevation Production
DISTURBANCE RESPONSE GROUP DEVELOPMENT Response to Different Disturbances Fire Grazing Flooding Drought Insects Invasive Species, Etc. Any combo of the above Resilience of Sites Slope Disturbance PPT/WHC Soils Vegetation
GROUP DEVELOPMENT MLRA 24 Nevada example 54 ESD s 12 DRG s Each group has a MODAL ecological site Largest acreage STM is developed for modal
MLRA 24 NEVADA EXAMPLE Group 2 Concepts Shadscale, budsage, ricegrass, squirreltail Rooting depth ~3-15 Soils: loamy, high in ash, carbonates near surface, no mollic epipedon Slopes 2-8%, Elevation 4000-6000 PPT: 5-8 MODAL = Loamy 5-8 Loamy Slope 5-8 Shallow Silty 8-10 Shallow Silty 5-8 Sandy 5-8 Gravelly Loam 5-8 1,510,676 acres 61,312 acres 11,950 acres 9,866 acres 8,931 acres 4,217 acres
GEODATABASE LAYERS: FIELD PREPARATION DATA LAYERS Ecological site type locations Soils lab pedons BLM Land Ownership BLM Historical Wildfire data, up to 2008 NRCS Soils data Ecological Sites (derived from soils data) REFERENCE MAP LAYERS Public Land Survey System (PLSS) County boundaries NDOT roads National Agriculture Imagery Program (NAIP) aerial photography USGS Digital Raster Graphics (DRG) topo quads
SOIL-SITE LOCATION & FIRE HISTORY ArcGIS 9.2: view and query data in the field Navigate and collect point locations Access site history: soil mapping, wildfires, etc.
FIELD VISITS Modal is focus EVERY ecological site multiple states Soil-Site Correlation Expert Team discusses site dynamics and improves draft model Rangeland Health Photos Notes
MLRA 24 DRG Wyoming sagebrush: Loamy 8-10 1,013,062 ac 9 sites Salt Desert: Loamy 5-8 1,510,76 ac 5 sites Sodic / Shadscale: Sodic Terrace 6-8 523,482 ac 1 site Sodic / Greasewood: Sodic Flat 6-8 214,462 ac 3 sites
MLRA 24 DRG Winterfat: Silty 4-8 72,933 ac 4 sites Claypan / Low sage: Claypan 12-16 127,913 ac 3 sites Black sage: Shallow calcareous Loam 8-10 386,480 ac 4 sites Mtn sagebrush: Loamy 12-14 219,193 ac 5 sites
MLRA 24 DRG Sandy / Basin big sagebrush: Sandy 8-10 132,919 ac 4 sites Basin Wildrye / big sagebrush: Dry Floodplain 156,866 ac 2 sites Basin Wildrye / greasewood: Saline Bottom 243,129 ac 5 sites Sodic / Alkali sacaton: Sodic Floodplain 21,062 2 sites
LOAMY 5-8 (NV) Community Phase 2.2
Community Phase 3.1: Shrub Cheatgrass Community Phase 3.3: Seeded Community Phase 3.2:Halogeton
LOAMY 5-8 (NV) Community Phase 4.1: Annual Grass Community Phase 4.2: Annual Forb
LOAMY 5-8 (NV)
GROUP 2: SHALLOW SILTY 5-8 (NV) STM is same Shrub State 2: CP 2.2 Ecological Dynamics: Limited cheatgrass Soil chemistry Water Annual State 4: CP 4.2 Eroded State 5
CONCLUSION DRG s expedite conceptual STM development Local Expert team is critical for success Soils, vegetation, disturbance, GIS STM External Review