Research Needs

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