Suchergebnisse

AbstractPopulation growth and overdevelopment are driving complicated interactions between human and natural systems. A preliminary investigation of human and natural systems as hierarchical, complex systems suggests that problematic, emergent behaviours are the result of 'induced coupling' between the two systems. Human manipulations aimed at mitigating natural disasters often change how human and natural systems interact by linking their behaviours in space and time. The dynamics of each separate system are fundamentally altered when they become coupled. This coupling drives unexpected, emergent behaviours through the introduction of strong, nonlinear feedbacks. Human–landscape interactions present a unique challenge because of the mismatch in scales between coupled processes. Induced coupling describes problematic system behaviours (e.g. natural disasters intensified by human actions) as the product of coupling short‐term human activities to long‐term natural processes. As a descriptive model, induced coupling draws upon the conceptualization of human and natural systems as hierarchical complex systems, and it utilizes a systems dynamics approach to identify delays introduced by human manipulations. Induced coupling aides in the description and analysis of coupled human–landscape interactions, and provides a focus for numerical modelling and identification of leverage points for management actions. Copyright © 2009 John Wiley & Sons, Ltd.

In the global South, a rush of large-scale land acquisitions (LSLAs) is occurring by governments and transnational and domestic investors seeking to secure access to land in developing countries to produce food, biofuels, and other agricultural commodities. Complex interactions between regional and global market dynamics and local institutional, socioeconomic, and agro-ecological conditions can lead to widely varying causal processes, land-use change (LUC), and socioeconomic and environmental outcomes. Systematic understanding of how characteristics of LSLAs across multiple social and environmental contexts produce spillover effects on local communities, ranging from employment opportunities to displacement and indirect land-use change (iLUC), is lacking. We conceptualize agricultural commodity production and land-acquisition processes associated with LSLAs as catalyzing causal pathways of direct and indirect land-use changes. Using the case of economic land concessions (ELCs) in Cambodia, we employed a novel synthesis research approach combining remote sensing, spatio-temporal statistics, and case study meta-analysis to construct archetypical pathways of the causes, timing, and consequences of ELC-driven land change. Archetypical pathways generally diverged based on specialized or flex commodity crops and rates of direct LUC, and rapid rates of direct LUC tended to cause displacement and iLUC. In contrast, ELCs producing commodity crops associated with more gradual land-use change and/or organized local resistance lead to less iLUC. Systematic knowledge generated through synthesis of local causes and consequences of LSLA-driven land change is now possible and needed to better address the direct and indirect consequences of LSLAs for commodity crop production.

Counterdrug interdiction efforts designed to seize or disrupt cocaine shipments between South American source zones and US markets remain a core US "supply side" drug policy and national security strategy. However, despite a long history of US-led interdiction efforts in the Western Hemisphere, cocaine movements to the United States through Central America, or "narco-trafficking," continue to rise. Here, we developed a spatially explicit agent-based model (ABM), called "NarcoLogic," of narco-trafficker operational decision making in response to interdiction forces to investigate the root causes of interdiction ineffectiveness across space and time. The central premise tested was that spatial proliferation and resiliency of narco-trafficking are not a consequence of ineffective interdiction, but rather part and natural consequence of interdiction itself. Model development relied on multiple theoretical perspectives, empirical studies, media reports, and the authors' own years of field research in the region. Parameterization and validation used the best available, authoritative data source for illicit cocaine flows. Despite inherently biased, unreliable, and/or incomplete data of a clandestine phenomenon, the model compellingly reproduced the "cat-and-mouse" dynamic between narco-traffickers and interdiction forces others have qualitatively described. The model produced qualitatively accurate and quantitatively realistic spatial and temporal patterns of cocaine trafficking in response to interdiction events. The NarcoLogic model offers a much-needed, evidence-based tool for the robust assessment of different drug policy scenarios, and their likely impact on trafficker behavior and the many collateral damages associated with the militarized war on drugs.