Non-Native Invasive Species: Red Brome (Bromus rubens) and the Sonoran Desert Wendy McCourt and Dr. Eddie Alford (Advisor) Arizona State University, Wanner Hall 6073 S. Backus Mall, Mesa, AZ Prediction For 2030 Unless current and future management methods break non-native pest cycles, the goal of sustainable pest and weed management will be unobtainable. Red brome is in its early stages of transforming desert scrub, shrub- steppe, and desert grasslands into monocultures with frequent fire, leaving hallmarks of the Sonoran desert such as palo verde trees and cacti at risk. Without effective management, abundance and distribution of red brome in the Sonoran desert will increase, fires will cause palo verde and cacti mortality, and abundance and distribution of native grasses will decline. LESSONS LEARNED FROM CURRENT MANAGERS 1.Research indicated that management should focus on prevention rather than eradication of non-native plants, and that computer- based mapping was an advantage. Figure 2. Plot of invasive species ranked using the Alien Plant Ranking System, showing ease of control versus level of impact. Size of dot represents the pest score on a scale from 1 to 100 (Crimmons et al, 2008). 2.Applying 40% of management efforts on the communication, education and information delivery of weed science and 60% on people and communities would be successful in locations where non- native invasive plants are not yet present in epidemic proportions. 3.Public awareness and funding for management of invasive species that are in early stages of infestation must occur in order to control weeds before management becomes simply unaffordable. 4. The Professional Development Program Grant funded by Western SARE provides a low cost yet highly technical way for landowners to digitally map non-native invasive plants so they can be properly monitored and eradicated. Abundance Thriving in resource limiting environments, non-native invasive plants out-compete native species for resources such as moisture, light and nutrients. Non-native plant species alter the evolutionary pathway of native species changing how the landscape looks and functions (Mooney and Cleland, 2001). Distribution Rapid establishment or persistence of non-native plant species occurs because their natural predators and disease are not present. Invasiveness of an introduced species may not be known for decades due to the normal population growth lag phase, environmental change shortly after establishment, or decreased genetic variation to founder species. These mechanisms keep initial populations of non-natives at low levels until conditions are favorable (Crooks and Soule, 1999). Issues Displacement of native species cause significant changes in natural fire regimes which lead to devastating losses of even more native species. Decreasing biodiversity results from competitive exclusion and hybridization, which further leads to niche displacement and extinction (Mooney and Cleland, 2001). Changing needs of land use can further alter the composition of biotic communities and global climate change. Global commerce has also had a substantial effect on introduced species which pose both pros and cons. Figure 1. Conceptual model of interactions and positive and negative influence (adapted from Dukes and Mooney, 1999). 1. Crimmins et al (2008) developed an Exotic Plant Management Plan for 50 exotic plant species for two Arizona monuments. 2.Howery et al (2005) determined the best methods to raise public awareness of the threats that non-native invasive plant species pose, how to best organize citizen participation, and how best to strengthen land owner management strategies of non-natives. 3.Fenner (2008) detailed the effects of invasive species. 4.Western Sustainable Agricultural Research and Education (SARE) developed and funded a sustainable pest and weed management project (2007). PAST APPROACHES FOR NON-NATIVE SPECIES MANAGEMENT CURRENT TRENDS Initiate more public awareness and support programs Comprehensive digital mapping of non-native invasives Develop pest potential criteria specific to rangeland regions and agricultural areas Develop non-native invasive plant management plan that will increase the ability of resource managers to analyze the needs of their infested areas Crimmins, T. M., Mauzy, M. S., and Studd, S. E Assessing Exotic Plant Distribution, Abundance, and Impact at Montezuma Castle and Tuzigoot National Monuments in Arizona. Ecological Restoration 26:1, pp Crooks, J. A. and Soule, M. E Invasive Species and Biodiversity Management, eds., pp Fenner, P Effects of Invasive Plants on Public Land Management of Pinyon-Juniper Woodlands in Arizona. USDA Forest Service Proceedings RMRS-P-51. Howery, L., Fernandez-Gimenez, M., Brunson, M., Brunson, M., Haynes, N., Lee, R., and Gleason, J Southwest Rangeland Invasive Plants Initiative, University of Arizona. Mooney, H. A. and Cleland, E. E The Evolutionary Impact of Invasive Species. PNAS. 98:10, pp Western SARE Projects. IMPLEMENTATION PROPOSED STRATEGIES Public awareness Obtain early knowledge of presence and rapid response Statewide coordinated approach of integrated treatment strategies and priorities Data sharing Research specific to Southwestern ecosystems Research addressing specific forest-climate interactions REFERENCES Global Commerce Non-native Species Native Species Ecosystem Processes Global Change /+