Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2006
Publication Date: 8/6/2006
Citation: Peters, D.C., Monger, H., Herrick, J.E. 2006. Changes in perennial grass recruitment from 1858 to present following woody plant invasion [abstract]. 91st Ecological Society of America Annual Meeting, August 6-11, 2006, Memphis, Tennessee. p. 99.
Technical Abstract: Desert ecosystems of the American Southwest have experienced dramatic changes in vegetation structure and soil properties over the past several centuries with the expansion of native woody plants. This conversion from perennial grasslands to shrublands is often difficult to reverse as a result of soil degradation and low grass seed availability. Additional recruitment processes that can limit the return of grasses are seed germination and seedling establishment, processes that are affected by both soil properties and vegetation structure. Our objective was to examine and compare the probability of recruitment of the perennial grass, Bouteloua eriopoda (black grama), in 1858 and at present using the simulation model of daily soil water dynamics. We used the model to simulate recruitment probabilities of black grama for the variation in conditions found at the Jornada Basin ARS-LTER site in southern New Mexico. Vegetation and soils maps for both time periods and historical weather data were used to parameterize the model. In general, simulated recruitment probabilities were higher in 1858 when the Jornada was dominated by grasslands compared with the present, shrub-dominated system. Because recruitment of black grama is nonlinearly related to silt content of the soil and to aboveground plant cover, these changes in recruitment probabilities were dependent on location-specific changes in soil properties and vegetation cover. Our results were used to identify the locations and conditions where recruitment of black grama is still possible; these areas can then be targeted for remediation efforts. We also identified the locations where remediation efforts of this grass species will fail without significant modifications to soil properties and vegetation cover. This approach to stratifying landscapes by recruitment potential can be used for other invasive species.