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Presentation on theme: "ECOLOGICAL SITES EXPANDING the CONCEPTS and APPLICATIONS of ECOLOGICAL SITES Joel Brown USDA NRCS Jornada Experimental Range Las Cruces NM."— Presentation transcript:


2 IMPORTANT POINTS Changing Conceptual Basis of Ecological Sites Applications - How can Ecological Sites be used for land management decision-making? Arcadia

3 Ecological Site: A distinctive kind of land with specific physical characteristics that differs from other kinds of land in its ability to produce a distinctive kind and amount of vegetation, and in its ability to respond to management actions and natural disturbances. The purpose of an Ecological Site system is to divide landscapes into basic units for study, evaluation, and management Ecological Site Description (ESD): Reports with associated data that document the characteristics of an ecological site (including its climate, soils, and state-and-transition model) and the interpretation of its properties related to use and management.

4 Ecological Site History: The site concept has undergone major revisions since its original development: 1.Time: A shift from linear, predictable dynamics to an approach based on nonequilibrium dynamics (probabilities) 2.Space: climate, geology, and edaphic properties are grouped together based on how they respond to change

5 Important Concepts In Dividing the Landscape Spatial scale – what is a site? Temporal scale- how does change occur?

6 Geographic areas with similar soils Similar landscape patterns Groups of Ecological Sites that share landscapes Intermingled ecological sites or single site Individual representative of the site An observation of plant-soil relationships Regions with similar climate, land use

7 LAND RESOURCE REGIONS LRR J-SOUTHWESTERN PRAIRIES 84A – Cross Timbers (Kansas, Oklahoma, and T exas) 84B – West Cross Timbers (Oklahoma and Texas) 84C – East Cross Timbers (Texas) 85 – Grand Prairie (Oklahoma and Texas) 86 – Texas Blackland Prairie (Texas) 87 – Texas Claypan Area (Texas) MLRAs

8 Non-native grass invasion, increased fire frequency, loss of native woody plants Drought-triggered forest dieback Non-native grass invasion, altered surface hydrology, reduced productivity Perennial grass loss, soil erosion, native woody plant dominance Nonnative woody plant invasion Native woody plant thickening, reduced fire frequency MLRAs distinguish broad differences in potential and types of ecological dynamics Major Land Resource Areas USDA NRCS

9 Loamy soil (active piedmont) Susceptible to water erosion and grass loss: vulnerable/restorable Clayey soil (basin floor) Receives water and sediment: low risk Limestone Grass protected by rocks, higher rainfall, good water capture: low risk Soil mapping units of the Jornada Basin (15 km) Gravelly soil (shallow, relict piedmont) Surface soil water limited, high risk for grass loss and erosion: vulnerable/restorable Sandy soil (relict basin floor) Erodible surface soils once grasses removed: vulnerable/hard to restore The LRU (local climate, soils and geology) refines and supports MLRA concepts From Bestelmeyer et al 2010

10 Within LRUs are clusters of sites with similar parent material, but differing in landscape position Each site has a typical soil profile

11 An ecological site groups several similar soil map unit components Map unit/components Ecological site ST: Stellar association 40% Stellar clay loam, 0-3% slopes = Clayey 40% Stellar clay loam, 0-3% slopes, flooded = Bottomland 20% other inclusions BK: Berino-Dona Ana association 50% Berino fine sandy loam, 1-5 % slopes = Sandy 30% Dona Ana fine sandy loam, 1-5% slopes = Sandy 20% other inclusions OP: Onite-Pajarito association 40% Onite loamy sand, 1-4% slopes = Sandy 30% Pajarito fine sandy loam, 0-5% slopes = Sandy 15% Pintura fine sand, 0-5% slopes = Deep sandy 15% other inclusions A soil map unit can contain more than one ecological site because map units may contain components

12 Ecological Site Concept An Ecological Site is based on a core concept with a defined amount of variability (in the climatic, geologic and edaphic properties). Variability in the temporal dynamics of the vegetation is not considered. An Ecological Site Description describes the distinguishing geophysical properties of a site in one section and its temporal dynamics in another section.

13 Describing Temporal Change Soil/Vegetation Concepts Existing vegetation can not be a primary ecological site criterion because it is easily manipulated therefore highly variable. The ecological site concept should be developed, using geophysical attributes that enable identification of the ecological site without vegetation on the site.

14 The utility of Ecological Sites is based on the ability to systematically stratify the landscape according to varying ecological potential Applications of Ecological Sites and Ecological Site Descriptions

15 Assess the risk of persistent degradation (undesirable change) and take proactive measures to avoid it Uses of Ecological Sites and Ecological Site Descriptions Transition (T) Slow variables and triggers Chronic heavy defoliation coupled to multi-year drought events Threshold Black grama grass cover loss to < 3% and inability to recover continuity via vegetative growth

16 Uses of Ecological Sites and Ecological Site Descriptions Specify constraints to desired ecosystem change, estimate their probability of occurrence and devise contingencies

17 Design and interpret monitoring based on expected responses to management or climatic changes. Uses of Ecological Sites and Ecological Site Descriptions

18 Ecological Site Information Applications at Larger (LRU, MLRA and LRR) Scales Information can be aggregated (Inventory) SpatioTemporal pattern detection (Prediction and Intervention) Predicted responses to climatic, socioeconomic factors (Modeling) Impacts of policy and program decisions (Assessment)

19 Narratives for states and communities contain indicator values and management strategies to promote resilience. Knowledge of the amounts and spatial distribution of these requirements can inform policies and programs Reference state Black grama-creosotebush savanna (historical + extant) Indicators/Diagnosis Bouteloua eriopoda >15% foliar cover, Larrea tridentata <12% foliar cover, little erosion Ecological Feedbacks Perennial grass continuity promotes soil and water retention and fire Management Summer grazing rest in drought, fire every 20 years Reference community phase Bouteloua eriopoda (15-60% foliar cover), Larrea tridentata (1-5% foliar cover) At-risk community phase Bouteloua eriopoda (3-5% foliar cover), large bare patches Alternative states Shrub-dominated, shrubland states 1.3 At-risk community 1.2 Another Community 2.1 Community 1.1A 1.Savanna state 2. Shrub-dominated state 3. Shrubland state 1.1 Reference community 3.1 Community T1A T2A R1A 2.2 Community 1.2A 1.2B 1.3A 2.1A 2.2A

20 To date the application of Ecological Site concepts has been limited to rangeland ecosystem dynamics Loamy SD-2 As Ecological State changes, the values and ecosystem services associated with the site change Burrograss Tarbush/Creosotebush Mesquite/creosotebush Tobosa/burrograss Tarbush or mesquite Tobosa/burrograss Threeawn Black grama Tobosa Black grama Black grama-tobosa grassland Tobosa Burrograss Threeawn Burrograss-tobosa-threeawn grassland Shrub-invaded grassland Shrub-dominated Black grama Tobosa 1a 2a 3a 4 Tobosa Dropseeds Burrograss Tobosa Threeawn (Yucca) Threeawn Mesquite Tobosa Tarbush Mesquite/Yucca Threeawn 2b 3b 5 1b Tobosa/ Black grama Mesquite

21 ECOLOGICAL STATE ECOLOGICAL SITE CLIMATE SOIL PROPERTIES LANDSCAPE POSITION GEOMORPHOLOGY ECOSYSTEM SERVICES PROVISIONING food, fibre SUPPORTING water cycling, nutrient cycling, primary production CULTURAL educational, recreation, heritage REGULATING climate, waste control, pollination HISTORICAL AND CURRENT MANAGEMENT PRIOR ECOSYSTEM SERVICESFUTURE ECOSYSTEM SERVICES From Brown and MacLeod 2011 Land Use and Land Management Changes Can Alter Ecosystem Services Regardless of Land Use

22 Land cover/use classifications are increasingly useless in making policy decisions people change land use frequently ecological processes are much more complex and variable than a land use category resistance and resilience are vital to predicting ecosystem behavior landscape scale models require ecological process information to allow sites to interact

23 The status of ecological sites In May 2010 agreement by NRCS, Forest Service, and Bureau of Land Management to adopt ecological sites as a common framework Interagency ecological site working group is being formed November 2010 Interagency Workshop-Pilot projects for developing ecological sites following interagency requirements being considered for certain MLRAs (regions). August 2011 Interagency Field Workshop Cheyenne WY November 2011 Interagency Field Workshop Venus FL 2012-Reno NV, Cheyenne WY New Soil Ecology division within NRCS National Soil Survey Center and new staff in regional offices: 53 new full-time positions dedicated to ESDs, including cropland

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