Emergent role of critical interfaces in the dynamics of intensively managed landscapes

Abstract

Complex interactions among water, dissolved and suspended material, and gases occur within the critical zone. These interactions depend upon and influence geologic and geomorphic processes, the chemical composition of constituents, and biological activities of microbes, higher organisms and associated ecological communities. All these components of the critical zone are co-evolving through inter-dependencies that extend over various space and time scales. In intensively managed agricultural landscapes, critical zone interactions are extensively disrupted to facilitate agro-ecosystem services. However, such disruptions are not evenly distributed across the landscape. Our research, conducted over eight years at the Intensively Managed Landscapes Critical Zone Observatory, demonstrates that the dynamics of intensively managed critical zones do not operate uniformly across time and space. Instead, critical interfaces, or zones of transition between different aspects of the landscape system, play a disproportionately important role in regulating material fluxes through mechanisms of storage, transport, and transformation, often through threshold responses and intermittent connectivity across these interfaces. We provide insight into how critical interfaces affect the intricate dynamics of water, energy, carbon, nutrients, and sediment in intensively managed landscapes. Since anthropogenic activities are continually and extensively modifying critical interfaces, sound understanding of the impact of these modifications is essential for intensive management to also be sustainable management.