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Part I: What’s the reference? 1. 2 3 4 ? 5 The rangeland health reference is based on what is possible (long-term ecological potential) for a particular.

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Presentation on theme: "Part I: What’s the reference? 1. 2 3 4 ? 5 The rangeland health reference is based on what is possible (long-term ecological potential) for a particular."— Presentation transcript:

1 Part I: What’s the reference? 1

2 2

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5 ? 5

6 The rangeland health reference is based on what is possible (long-term ecological potential) for a particular soil and climate combination (i.e. ecological site) S&T models indicate what is realistic (based on short-term potential and limited resource availability) (i.e. communities in an ecological state) 6

7 Knowing what’s possible provides: u Consistent standards for inventory, assessment & monitoring u Complete range of management options 7

8 Knowing what’s realistic provides: u A secondary standard for inventory, assessment & monitoring u Complete range of management options 8

9 Thresholds (Relatively Irreversible Transitions) Community A Community Pathway Reference State Shrub/Native Perr. Grass Alternative State Shrub/Exotic Annual Grass – Increased Fire Exotic Annual Grass – Increased Fire Alternative State 9

10 SUMMARY -- S&T models u Ecological site-based state & transition conceptual models can be used in two ways. 1) The “reference state” = what is possible based on ecological site potential 2) Communities within a current state = what is realistic 10

11 SUMMARY -- IIRH and S&T are used: –To determine departure from the reference state »None to Slight – expected for the ecological site and falls within the range of variation for the indicator (no threshold crossed) »SM, M, ME - indicates that a threshold is being approached or has already been crossed »Extreme to Total – Up to and including maximum possible departure for the indicator 11

12 SUMMARY -- IIRH and S&T are used: (cont) –To identify specific issues of concern (erosion, hydrology, biotic integrity) –To help identify and communicate management options 12

13 Part I: What’s the reference – using IIRH together with S&T models Part II: Reference sheet development overview 13

14 Reference sheet development (pages 21-25, 72-74) Capture spatial and temporal variability (including short-term disturbance effects)! Page 74 14

15 Reference sheet development (pages 21-25, 72-74) Reference Sheet defines the “None to Slight” Category in the Evaluation Matrix Page 25

16 Community A Community Pathway Reference State Shrub/Native Perr. Grass Alternative State Shrub/Exotic Annual Grass – Increased Fire Exotic Annual Grass – Increased Fire Alternative State A Reference Sheet is developed for the “Reference State” of each ecological site… 16

17 Indicators. For each indicator, describe the potential for the site. Where possible, (1) use numbers, (2) include expected range of values for above- and below-average years for each community and natural disturbance regimes within the reference state, when appropriate and (3) cite data. Continue descriptions on separate sheet. Composition (indicators 10 and 12) based on: __ Annual Production, __ Foliar Cover, __Biomass Page 74 17

18 1. Number and extent of rills: 1. Number and extent of rills: Minimal on slopes less than 10% and increasing slightly as slopes increase up to 50%. Rills spaced 15–50 feet apart when present on slopes of 10–50%. After wildfires, high levels of natural herbivory or extended drought, or combinations of these disturbances, rills may double in numbers on slopes from 10–50% after high intensity summer thunderstorms. Composition (indicators 10 and 12) based on: __ Annual Production, __ Foliar Cover, __Biomass Page 74 18

19 Generating the reference sheet u What do you need to define potential for an ecological site? –Ecological Site Descriptions –Soil survey information –Ecological Reference Area(s) –Expert knowledge (old timers and brilliant ecologists) –Other data (e.g. from LTER and other long-term studies) 19

20 What if I don’t have… u u A state and transition model? u u An ecological site description? u u A soil survey? 20

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22 Generating the Reference Sheet u How do you evaluate the quality of the information? –Go to the source, or people who knew it –Compare different sources 22

23 No Reference Worksheet: don’t bother going to the field! T.K. Stringham and others State and transition modeling: An ecological process approach. Journal of Range Management 56: J.E. Herrick and others An integrated framework for science- based arid land management. Journal of Arid Environments 65:


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