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Dynamics of Shrublands and Grasslands to Novel Ecosystems: Past, Present, Future Diversity

Explore the evolution of shrublands and grasslands into novel ecosystems, analyzing environmental drivers, soil-geomorphic templates, and the invasion of woody plants. Investigate the impacts of perennial grassland and the introduction of exotic grasses on ecological dynamics.

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Dynamics of Shrublands and Grasslands to Novel Ecosystems: Past, Present, Future Diversity

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  1. SHRUBLANDS OR GRASSLANDS TO NOVEL ECOSYSTEMS Deb Peters, Jin Yao

  2. Jornada LTER framework (alternative states, multiple scales, spatial and temporal context) Past Future states Present Temporal context (legacies, lags, feedbacks, past & recent management practices, climate, disturbance) Environmental drivers (climate, grazing) Perennial grassland Woody plant invaded grassland Soil-geomorphic template Transport vectors Perennial grassland plant Coppice duneland plant assemblage landscape unit Novel systems (exotic grasses) Ag land Spatial context Resource redistribution Shrubland Urban, suburban, agricultural

  3. Lehmann lovegrassoccurrence at Jornada in the 1950s and 1960s, JER staff seeded Lehmann lovegrass for restoration or spring forage with limited success. Current populations are probably from seeds transported downslope from seeded populations. ERLE patches and presence GPSed during 1998-2001 by McGlone CM. C SAND G SUMM C CALI McGlone CM. 2001. Response of an introduced grass, EragrostisLehmanniana, to a prescribed burn in the Northern Chihuahuan Desert: Implications for community dynamics. NMSU Master Thesis.

  4. Lehmann lovegrassincreased on long-term NPP plots in wet period (2004-2008; die off with freeze in 2011) Frequency data from NPP locations % of quadrat with ERLE C SAND G SUMM C CALI McGlone CM. 2001. Response of an introduced grass, EragrostisLehmanniana, to a prescribed burn in the Northern Chihuahuan Desert: Implications for community dynamics. NMSU Master Thesis.

  5. Regionally, Lehmann lovegrasshas expanded throughout the Southwest (county-level reporting) Lehmann lovegrassexpansion (exploded) in Sonoran Desert in 1990s; maintained thru time Frequency (%) Santa Rita, AZ Invasive grass from South Africa Frequency (%) Basal cover (%) Data source: USDA plants database

  6. Lehmann lovegrassinvasion as a novel ecosystem in the Chihuahuan Desert Objectives I. To quantify the climatic and edaphic controls on Lehmann lovegrass seedling establishment and survival for: 1. theJornada landscape 2. the ChihuahuanDesert II. To predict its future geographic distribution under alternative climate scenarios. Collaboration with EF – 1065699 (2011-2016)

  7. SOILWAT model parameterization and validation SOILWAT • Daily time step, multi-layer model of soil water dynamics and seedling establishment • Parameterized using literature values for Lehmann lovegrass and similar native grass species Model validation • Field observations vs. simulated results • Jornada (Chihuahuan Desert) vs. Santa Rita (Sonoran Desert)

  8. Chihuahuan Desert simulated seedling establishment • Establishment simulated for 57 weather stations representing Chihuahuan Desert • Current daily precipitation and temperature • Alternative climate scenarios Temperature increase by 2.5 oC Vary precipitation amount (no change, decrease or increase by 10%) 4. 6 soil types 5. Extrapolate to entire region using regression equations and PRISM climate data

  9. Regression equations for extrapolation - Loamy sand and sandy loam (examples)

  10. PRISM data for current climate 1981-2010 Mean annual precipitation Mean annual temperature

  11. Regional variation in change in seedling establishment on loamy sand soils (mesquite) Current climate Hotter, PPT no change Hotter and drier Hotter and wetter

  12. Sandy loam soils greater change in establishment than loamy sand soils sandy loam (grassland) loamy sand (mesquite) Current climate Current climate Hotter and drier Hotter and drier

  13. Lehmann lovegrassinvasion as a novel ecosystem in the Chihuahuan Desert Objectives - future I. To quantify the climatic and edaphic controls on Lehmann lovegrass seedling establishment and survival for: 1. theJornada landscape – future plans are to simulate the Jornada under climate change scenarios 2. the ChihuahuanDesert II. To predict its future geographic distribution under alternative climate scenarios. III. Continue long-term monitoring of Lehmann’s populations IV. Model results lead to mechanistic field studies

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