2012 Annual Report
1a.Objectives (from AD-416):
We propose a research strategy to address how the shortgrass steppe (SGS) may change under projected global change and land-use change scenarios. We will apply an integrative approach of monitoring, manipulative experiments and modeling to investigate the mechanisms underlying current structure and function and how these will be altered under projected future changes. The overarching question that guides this research is: How will SGS structure and function respond to changes in climate, management practices, and land-use? It is unclear to what extent SGS will maintain its current structural and functional characteristics under conditions predicted by global climate models and shifts in land uses. As such, any changes to SGS structure and function will affect not only the natural system and the common vegetation states, but also alter the relationship between the natural system, humans and land-use.
1b.Approach (from AD-416):
We will investigate four research themes by integrating long-term monitoring, experimental manipulations, and modeling. The four themes and guiding questions for a suite of experiments are:.
1)Climate: How has climatic variation shaped the structure and function of SGS, and how will projected climate change influence processes? We will study how changes in precipitation regimes using the pulse-dynamic framework, affects above- and belowground community structure and interactions, aboveground trophic and disease interactions, nutrient dynamics, plant phenology, and plant genotypic structure,.
2)Physiography: To what extent are ecological dynamics and responses to global change contingent on upon physiography? We will study ecohydrological and pedological controls on water distribution within and among landscapes and how landscape variability influences aboveground productivity, species composition, key processes, and sensitivity of SGS to forecasted climatic change,.
3)Grazing, Fire and Land-use Change: How will alterations in grazing, fire, land-use and their interactions modify the structure and function of SGS? We will study how alterations in type and intensity of grazing, and interactions among grazing, fire and land-use change affect above- and belowground community composition, structure and production, diversity, and nutrient dynamics, and.
4)Synthesis and Projections/Forecasting: How do climate, grazing, and land use change influence the SGS over multiple spatial and temporal scales? We aim to improve model-data synthesis at landscape scales by incorporating land-use and physiography into spatially explicit variations of our current models on soil development and food webs, and new meta-population models that incorporate historic and predicted land-use change.
Primary activities in 2012 focused on collection of vegetation data on long-term exclosures and baseline vegetation sampling from areas on which new sets of exclosures will be established later in 2012. Additionally, efforts have targeted development of shrub density maps for the Central Plains Experimental Range, and data entry and associated quality assurance of a large volume of data collected during the 2011 summer. ARS efforts were coordinated with the Colorado State University scientists through regular email and phone communications and site visits related to the datasets, vegetation sampling, and location of new exclosures.