Iterative driver-response dynamics of human-environment interactions in the Arizona-Sonora borderlands

Abstract

In complex social‐ecological systems, human and physical processes mutually condition one another through co‐adaptation at multiple scales from the local to the global. For this paper we modified a driver‐response conceptual model of social‐ecological interactions by considering the degree to which each binary set of processes (human or physical) is simultaneously a driver and a response to global change. Processes that we understood to be mutually conditioned offered greater potential compared to solely social or ecological communities to adapt to demographic and economic change, on the one hand, and to climate, water resources, and ecosystems dynamics, on the other. By considering case material from the United States&ndashMexico border region, we characterized social‐ecological interactions along a continuum from those acting exclusively as drivers to others reacting to change primarily as responses. We considered water resources to integrate multiple global change processes including climate change and variability, ecosystem resilience, and human water demands for a variety of purposes. Thus, we examined in detail two watersheds in the Arizona&ndashSonora borderlands representing mutually conditioned social‐ecological systems. First, the Río Magdalena in Sonora represented an illustrative case of smallholder agriculture and rural livelihoods engaged in social‐ecological interaction that exhibited both driver and response elements centered on reflexive, low‐impact adaptive strategies. Second, in Ambos Nogales relying on the Santa Cruz River and its associated aquifers, urban growth, the equity of water access for human purposes, and environmental quality represented especially pressing challenges. Here, human impacts on ecosystems were the predominant drivers although there was growing concern for the medium‐ and longer‐term implications of climate change. Adaption planning in Ambos Nogales was centered on infrastructure‐based solutions including an inter‐basin water transfer connection with the Río Magdalena. Wastewater flows to riparian corridors posed a particular challenge for human‐environment interactions. Cross‐border collaboration represents an important opportunity for adaptation based on the mutually conditioned interactions presented here. We summarized the analysis of both cases by raising conceptual questions for further enquiry and for adaptation and planning that are generic for the borderlands and beyond.