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Research Needs


Although some buffelgrass research has been completed, there is still a lack of scientific information to support and evaluate buffelgrass control methods, restoration after treatment, or adaptation in the event that control is not possible and fire-resistant desert becomes flammable grassland.

A working list of buffelgrass research needs is provided below and additional information may be referenced in Appendix 6 of the Southern Arizona Buffelgrass Strategic Plan.

Originated: April 3, 2002
Updated: January 11, 2010
 

Biodiversity and Ecosystems

  • Mechanism of invasion, competition and spread
    • Level and type of disturbance that encourages spread?
    • What are the thresholds?
  • Spread and niche models for different strains of buffelgrass that take into account landscape structure, pathways of dispersal, and climate variability and change (Strategic Plan)
  • Ecological, physical or genetic processes that contribute to plant invasiveness
  • Impacts of buffelgrass on native plant communities
    • How and to what extent is buffelgrass affecting specific species; some work on columnar cacti (Morales-Romero), palo verdes (Elits – Huxman lab), cottontop (Jason Stevens)
    • What species are in direct competition and what resources are they competing for and to what degree? (rate, depth and quantity of water uptake)
    • Growth rates of saguaros and other key flora at different buffelgrass densities.
    • EX. Introduce buffelgrass into an area and see what gets displaced, stressed, changes in nutrient and water availability, changes in wildlife use….
  • What are the changes in community structure (light, height, density, etc.) and composition (richness, diversity) and what are the implications
    • Investigate relationship between buffelgrass (different strains) traits and the abiotic and physical environment to determine range limits and community composition
  • Use of buffelgrass by native fauna (insects, small mammals, birds, herps)
    • What is the forage potential for natives, structure and composition for shelter (favorable or not), habitat implications
    • Is there a density dependent relationship?

 Fire

  • Desert fires fueled by buffelgrass
    • What is going to happen to our ecosystem; infer some from red brome fires (Cave Creek – Tonto NF, Mother’s Day- Saguaro NP)
    • What are the below ground effects
  • Based on fire behavior models (under investigation by McDonald-McPherson) what #/acre, fuel spatial configuration, thresholds will carry fire
  • Fire behavior and effects – of natives in buffelgrass stands
  • Post buffelgrass fire implications on communities, recovery, soils, composition
  • Post-buffelgrass fire restoration (BAER)
  • Does fire kill the seed? Bury seeds at different depths.
  • Fuel loads at different densities and stages of decomposition

 Climate Change

  • Buffelgrass response (establishment, persistence, spread, etc.) to climate change
    • change in precipitation and temperature regimes,
    • CO2, GH gases, inc/dec levels of N, K, Phosphorus

 Soils

  • Are certain microbes in soil favoring the establishment and/or persistence of non-natives
  • Investigate relationship of soil nutrients, soil microbes, and buffelgrass
  • Changes in soil properties due to buffelgrass infestations
  • Is there an association of buffelgrass or other non-natives with N-fixators?
  • Impacts on biological crusts

 Seeds

  • At what point are the seeds viable
  • How drought tolerant are the seeds
  • How long can seeds persist in the soil and still be viable? Can seeds be dated
  • How large (mass) is the seed bank under buffelgrass stands of different ages

 Control

  • Herbicide efficacy trials
    • Investigate other herbicides or combinations of herbicides and adjuvants that would extend the window of treatment on buffelgrass
  • Phenological models (Strategic Plan)
  • Is there a relationship between age of infestation, density,…that influences number of treatments to exhaust seed bank
  • Biological controls
  • Decomposition of grass sprayed vs pulled vs senescent

 Restoration

  • To what extent do treated buffelgrass patches need restoration. (Strategic Plan)
    • What are the thresholds or indicators that more active restoration is necessary
    • What methods and techniques are effective

 Mapping and Monitoring

  • Effective techniques for mapping buffelgrass at landscape scale
    • Investigate different new imagery for detection (build on Olsson’s  findings)
    • Helicopter mapping (digital sketch mapping) and ground truthing methods
  • Map at higher elevations

 Economic

  • Economic impacts of buffelgrass
    • How much does Sonoran Desert contribute to the economy and what are the potential and real changes that buffelgrass can have on economics