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United States Department of Agriculture

Agricultural Research Service

Title: Modifying patch-scale connectivity to initiate landscape change: An experimental approach to link scale

item Peters, Debra - Deb
item Herrick, Jeffrey - Jeff
item Okin, Greg
item Pillsbury, Finn
item Duniway, Michael
item Vivoni, Enrique
item Sala, Osvaldo
item Havstad, Kris
item Monger, H. Curtis
item Yao, Jin

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2011
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Nonlinear interactions and feedbacks across spatial and temporal scales are common features of biological and physical systems. These emergent behaviors often result in surprises that challenge the ability of scientists to understand and predict system behavior at one scale based on information at finer or broader scales. Changes in ecosystem states under directional changes in climate represent a class of challenging dynamics of particular significance in many terrestrial ecosystems of the world. We are focusing on one system of global relevance and importance (conversion of arid grasslands to degraded shrublands). We are using a novel, multi-scale manipulative experiment to understand the key processes governing state changes, and to test specific hypotheses about how patterns and processes interact across scales to potentially reverse shrublands to grasslands or to other alternative states. We are using this experiment combined with simulation models to address two questions: (1) At what spatial scales do fine-scale processes propagate to exhibit broad-scale impacts? (2) At what spatial scales do broad-scale drivers overwhelm fine-scale processes? In this experiment, we initiate grass-soil feedbacks via the redistribution of resources at the plant and patch scale using Connectivity Modifiers (ConMods). These patterns are expected to propagate through time and space to influence grass dominance at the landscape scale with implications for regional scale land-atmosphere interactions. Initial results show that ConMods are effective in reducing horizontal water redistribution, and increasing local water availability to result in recruitment and growth of grasses and other herbaceous plants. We are integrating this information with a suite of process-based ecosystem-hydrologic-aeolian-atmospheric simulation models to investigate threshold dynamics and feedbacks across scales, and to predict alternative states under climate change. We believe this cross-scale approach will provide new insights into failed attempts to restore perennial grasslands that focused on individual scales, and will apply to state change dynamics in other ecosystems.

Last Modified: 10/17/2017
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