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July 29-330-Greg Schmidt
State and transition models (STMs) are tools that integrate ecosystem dynamics into management by defining alternative ecosystem states and the transitions between them. Climate relates to STMs by influencing ecological sites and the potential vegetation communities. As climate changes, STMs may need to consider shifting reference states and allow for novel communities. Applying STMs across mixed land uses adds complexity but can help assess conservation value under different land use states.
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July 29-330-Greg Schmidt
- 1. USDA is anequal opportunity provider, employer, and lender. Accounting for Climate in the Application of State and Transition Models on Landscapes with Mixed Landuse July 2019 | Greg Schmidt and Nels Barrett
- 2. Outline 1. Review: Whatis a state and transition model? 2. How does climate relate to ecological sites and STMs? 3. How can we use STMs in a changing climate? 4. How do multiple land uses affect STMs? 5. How do we assess the conservation value of different land use states?
- 3. Ecosites and Stateand Transition Models Jack Pine Forest Phase Dry Sand Prairie Phase Oak/Red Maple Forest State Jack Pine Barrens Phase *Reference Community NaturalSuccession MoreFire Red Pine Plantation State Suppress Fire Cut/Herbicide red maple, Burn, Plant jack pine Jack Pine Barrens Reference State* *Reference State -Natural Range of Variability A Guide to Management Options of the Site Clear Cut, Plant red pine
- 4. Vegetation Dynamics Scrub 1 –5 m Dry Woodland 5 – 25 m Moist Forest 25-40 m Desert Grassland Short Grassland Tall Grassland Seasonal HumidArid Moisture Disturbance Woody Herbaceous Fuel productionFuel dryness Fuel availability Unbroken Flat Landscapes Hilly Sheltered Landscapes Maximum height limited by moisture stress
- 5. 1.1 Emergent Marsh 1.4 Inundated ShrubSwamp 1.2 Wet Meadow 1.3 Swamp Forest Semi-permanentlypondedphases Stand Replacement Event Seasonallyponded/Saturatedphases Drier Wetter Disturbance Succession • Water table and degree of ponding in wetland can is sensitive to amount of precipitation and PET. • Complex Spatial Zonation based on wetness encompassed within poorly drained site concept. • Annual variability is encompassed by species life cycles and masks short term trends. • Short term (decadal) cyclical trends in climate translates to shifting spatial zonation boundaries. • Longer term unidirectional trends not accounted for in STM –commensurate with a change in drainage class and therefore a change in site concept. Wetland Ecosite Space Time Continuum Upland Meadow Or Wet Meadow Wet Meadow Or Emergent Marsh Emergent Marsh or Aquatic Bed Wet Decade Dry Decade Drier Wetter Disturbance Succession
- 6. Hillslope Space TimeContinuum +Moisture +Mineral Bases +OM +Nitrogen -Moisture -Mineral Bases -OM -Nitrogen Mesophytic lower slope vegetation: • Drought intolerant • Nutrient enriched Xerophytic upper slope vegetation: • Drought tolerant • Nutrient starved Drier climate will result in a downward shift in hillslope vegetation zonation Moister climate will result in an upward shift in hillslope vegetation zonation. Hawthorne, S. and Miniat, C.F., 2018. Topography may mitigate drought effects on vegetation along a hillslope gradient. Ecohydrology, 11(1), p.e1825. Vose, J.M. and Elliott, K.J., 2016. Oak, fire, and global change in the eastern USA: What might the future hold?. Fire Ecology, 12(2), pp.160-179.
- 7. Altitudinal Space TimeContinuum Warmer climate can expect upward shift in altitudinal vegetation zonation. Cooler climate can expect downward shift in altitudinal vegetation zonation. Subalpine Forest Montane Forest Deciduous Advantage • Warm Growing Season • Rapid Nutrient Turnover • High Peak Capacity for Photosynthesis Evergreen Advantage • Cool Growing Season • Slow Nutrient Turnover • Low Peak Capacity for Photosynthesis
- 8. Vegetation Climate ZonalSpace Time Continuum – Eastern US Temperate Mesophytic Deciduous Forest Temperate Oak Woodlands Temperate Pine Woodlands Subtropical Laurophyllous Evergreen Forest (Magnolia-Beech) Subtropical Sclerophyllous Evergreen Woodlands (Live Oak-Palmetto) Subtropical Pine Woodlands (Longleaf Pine) Hemiboreal Mixed Forest (Beech-Hemlock) Boreal/Subalpine Forest (Spruce-Fir) Warm Season Tall Grassland/Prairie (Big Bluestem) Cool Season Short Grassland/Steppe Tropical Moist ForestTropical Dry ForestTropical Savanna STM Site B STM Site A
- 9. Trends in thermaland moisture regimes (Southern Great Lakes Region) https://phytoclast.github.io/ClimateClassification/ 2070 1990 Holocene Optimum Glacial Maximum 2070 1990 Holocene Optimum Glacial Maximum Lat: 41.63°; Lon: -83.82°; Elev: 245 m MAAT: 9.1°C; MAP: 918 mm Warm Month: 21.9°C; High: 28°C; Cold Month: -4.9°C; Low: -9.3°C Growing Season Temperature: 17.4°C; Annual Extreme Low: -23.8°C P/PET: 1.55; Surplus: 382 mm; Deficit: 57 mm; Peak AET: 95 mm Warm-Mild (Lower-Montane) Meso-Temperate, Moist-Humid Isopluvial 20th and 80th percentile monthly precipitation plant physiognomic thresholds Normal climate variation = No change in normal range of possible vegetation Long term persistent change in climate = Complete turnover in species available.
- 10. Shifting Vegetation tothe Present Delcourt, Delcourt, & Webb, 1983
- 11. Fluid State andTransition Model Generic Forest Phase Generic Prairie Phase Generic Seminatural State Generic Barrens Phase NaturalSuccession MoreFire Generic Cultural State Everything by accident Restore Generic Natural Upland Low Nutrient Reference State* *Reference State -Natural Range of Variability • A Generic Guide to Management Options of the Site decoupled from a fixed climate. Change is gradual, outcome is uncertain – what is the threshold for a new alternative climate state? Or is it a shifting reference? • Relies heavily on functional vegetation ecology and knowing the autecology of individual species. • Priority given to locally native plant communities with higher mean species’ “conservancy” value indicating a reference condition, but change from historic composition is inevitable. By Design ? ? ? ? ? By Neglect
- 12. Multiple Use Landscape Rangeland Forestland Cultural Whatis the object of Conservation Focus? Sustainability of Human Life on Earth What do we need for this? • Cultural Services: • Food • Shelter • Ecosystem Services: • Clean Air • Clean Water • Building Materials • Biological Values: • All the critters required to keep giving you these… • Which means that not all NPP can go towards these… Natural Vegetation Cultural Vegetation • But a fragmented landscape offers an incomplete package
- 13. Aggregating Alternative Statesby magnitude of Ecological Integrity* Natural Vegetation — vegetation where ecological processes primarily determine species and site characteristics; that is, vegetation comprised of a largely spontaneously growing set of plant species that are shaped by both site and biotic processes. Semi-Natural Vegetation — vegetation in which past or present human activities significantly influence composition or structure, but do not eliminate or dominate spontaneous ecological processes activity. Semi- natural sites typically have no recent historical analogue, but may be composed of native or introduced species. Cultural Vegetation — vegetation with a distinctive structure, composition, and development determined by regular human activity. Often managed to obtain specific products to the exclusion of rest of the ecosystem. Includes cropland and urbanland. *Concepts expanded from United States National Vegetation Classification http://usnvc.org • Biological Values • Ecosystem Services • Cultural Services • Biological Values • Ecosystem Services • Cultural Services • Biological Values • Ecosystem Services • Cultural Services Conservation Practices? Conservation Practices? Conservation Practices? Ranking of Reference Status A – pristine reference B – imperfect, de facto reference C – needs restoration D – barely recognizable, lost cause Fail Seminatural Conservation ValueDefinitions ? ? ?
- 14. Wetlands Reference Ruderal Woody Ruderal Herbaceous Semi-Natural Vegetation CulturalVegetation: Urban or Agricultural Unsustainable Cultural Phases Sustainable Cultural Phases Conservation Feature • Cover Crop (340) • Conservation Crop Rotation (328) • Nutrient Management (590) • Integrated Pest Management (IPM) (595) • Conservation Cover (327) • Grassed Waterway (412) Forest or Shrubland Grassland • Prescribed Burning (338) • Early Successional Habitat Development/Management (647) • Brush Management (314) • Forest Stand Improvement (666) • Tree/Shrub Site Preparation (490) • Tree/Shrub Establishment (612) • Wetland Enhancement (659) • Wetland Restoration (657) • Wetland Wildlife Habitat Management (644) • Brush Management (314) • Herbaceous Weed Control (315) • Upland Wildlife Habitat Management (645) • Restoration and Management of Rare and Declining Habitats (643) • Brush Management (314) • Herbaceous Weed Control (315) Conservation Practices
- 15. Conservation Scale Small areaof distinctive composition, nested within a larger community. Microsites Small area, disconnected from site or without adjacent community Ecosystem Elements Limited maintenance of a static species composition across microsites Community Management of multiple successional phases irrespective of adjacent sites. Site Ecosystem Management of multiple adjacent sites, needed for wide ranging wildlife species. Landscape Ecosystem SpecieslistsSTM Agency Product Planning Level Shift in frame of reference due to high intensity environmental changes? Manage viability of entire species; Quarantine of invasive species and diseases Biotic Province Manage viability of area species pool irrespective of landscape Ecoregion/Ecological Inference Area Management of multiple biomes, adapting to climate readjustments; Quarantine of invasive species and diseases Biotic Realm Carbon and CFC emissions; fisheries; human populations; etc. Global MLRA GRIN Database
- 16. Biogeographic Hierarchy Biotic Province: EasternNorth American Forest & Woodland Division (USNVC) Ecological Inference Area: MLRA Nearctic Realm • Biotic Realm: area of species sharing a deep history of coevolution (native in the broadest sense) • Biotic Province: area of species sharing a more recent history of interaction through climate cycles, lacking barriers to migration. • Ecological Inference Area: smaller area of homogenous flora and fauna where composition is dependent only on local differences in substrate and climate.
- 17. Outline 1. What isa state and transition model? • Integrates ecosystem response to multiple inputs expressed as change in vegetation or land cover. 2. How do we capture climate variability in the context of a site description? • Currently, within the existing framework, climate variability is accounted for as internal dynamics. • These internal temporal dynamics translate into spatial dynamics within the site. • Internal dynamics can be scaled up beyond the single site to the landscape and beyond. 3. Can we develop credible templates that reflect complex dynamics? • Dynamics show patterns that are often repeated at different scales, and arrayed along various gradients (landform vs. altitude vs. latitude) that exhibit different expressions of vegetation at each level. • Despite complexity, there is still a restricted range of vegetation structure and function that can be represented by a generic STM with an underlying shifting community composition. 4. How do multiple land uses affect the development of a STM? • Uncertainty and variability among fragments in multi-use landscape makes it difficult to represent every combination of cover type, and may require aggregating alternative states according to the intensity of land use. 5. How can we assess the value of different states? • Within the reference state, we grade sites according to how well they function like the reference. • Among higher intensity land uses or greater intensity of change, we can adjust a larger ecological inference area to determine our new reference and to ensure we ensure the viability of native species where they can thrive.
- 18. Disclaimer The findings andconclusions in this presentation are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.
Editor's Notes
- #2 Climate and land use are two different things that complicate conservation planning. My goal is to provide a framework to think about these two problems.
- #3 Climate and land use are two different things that complicate conservation planning. My goal is to provide a framework to think about these two problems.
- #4 A state and transition model is an outline of the vegetation dynamics in context of the natural range of variability in climate and disturbance history, and potential land uses.
- #5 Spatial vegetation patterns are set by climate, but only with interaction with other factors like disturbance regime. Disturbance is often fire, wind, flood, and animal driven. Fire frequency = ignitions × fuels × connectivity.
- #6 Year to year variability in precipitation of will not change vegetation patterns as it encompasses the lifecycles of most perennial species. Individual species may be affected by short term wet or dry episodes that have an immediate effect on seedling establishment or adult plant mortality, but this maintains status quo. But variation by decade or longer is enough to change the relative position of vegetation zonation based on cumulative effect of wetter versus drier years on recruitment/mortality dynamics. Longer period variability is needed to systematically affect woody vegetation since it takes longer to reach structural maturity. [Generally, annual precipitation in Michigan expected to be ±20-25% for one out of ten years, and variation in decadal means are about ±10-15% one out of ten decades.]
- #7 Drier climate can expect downward shift in hillslope vegetation zonation: Moisture affected directly by virtue of lower cumulative flow of moisture downslope. Shift in nutrient gradient is more indirect: Losses of nitrogen to atmosphere due to fire. Losses of nitrogen via shift to species composition with lower quality leaf litter. However weathering of bases will be less severe. Wetter climate can expect upward shift in hillslope vegetation zonation.
- #8 Cooler climate can expect downward shift in altitudinal vegetation zonation. Warmer climate can expect upward shift in altitudinal vegetation zonation: isolated peaks may completely lose alpine and subalpine zones.
- #9 An array of possible vegetation formations that are affected by temperature and moisture regimes. Fire regime and site nutrient/moisture constraints must also be considered. Adjacent sites may overlap in the vegetation represented in their STM.
- #10 If precipitation variability should be considered in context of monthly potential evapotranspiration. Impacts of precipitation variability should be more significant for months with a potential for cumulative soil moisture deficit. Historic changes in thermal and moisture regimes have been dramatic, but should be put into a plant physiology and soil moisture context.
- #11 Compatibility of novel species composition assessed by considering natural geographic barriers and historic species migration. Species that we have since the last ice age are already filtered of species unable to find a suitable niches somewhere on the continent in context of the wide magnitude of change, though luck is also at play.
- #12 A climatically decoupled state and transition model allows for planning around alternative reference states if final vegetation trajectory is uncertain.
- #13 Natural habitat provides services not available in by cultural vegetation, but effectiveness declines with fragmentation.
- #14 Each land use decision potentially moves a site further from a reference optimum. Fragmentation, climatic adjustments, fickle markets, and continued invasive species introductions conspire to prevent this continuum of these novel states from reaching a new equilibrium. Prior to more detailed inventory, a set of generic alternative states can be defined in terms of their over all human footprint. Partially compromised reference conditions can be recognized as a grade, if species composition still recognizable to a natural community type. Conservation practices are intended to partially compensate or minimize loss in ecological integrity.
- #15 The types of conservation practices employed vary according to intensity of land uses.
- #16 Conservation planning must consider a landscape scale commensurate with the magnitude of environmental change. The object of conservation may shift away from “authentically original vegetation” on a particular site to that of the more desperate goal of viability of the whole biota somewhere in a novel landscape as it relates to a shifting “autecological window”.
- #17 A biogeographic hierarchy should be considered based on this history, to determine appropriate scale of plant conservation.