Conservation and conflict in the Democratic Republic of Congo: The impacts of warfare, mining, and protected areas on deforestation
Biological Conservation, Volume 191, November 2015, Pages 266-273
Van Butsic, Matthias Baumann, Anja Shortland, Sarah Walker, Tobias Kuemmerle
Abstract
Tropical forests provide critical ecosystem services worldwide. Nonetheless, ongoing agricultural expansion, timber extraction, and mining continue to jeopardize important forest resources. In addition, many tropical forests reside in countries that have experienced violent conflict in recent decades, posing an additional, yet poorly understood threat. Conflict may decrease or increase deforestation depending on the relationship between conflict and other causes of land use change, such as mining expansion or protected area establishment. The Democratic Republic of Congo (DRC), home of the second largest tropical forest in the world, has experienced 20 years of violent conflict, resulting in the death of over 100,000 combatants and up to 5 million civilians. Expanding mining concessions also threaten the DRC's forest, even though nearly 12% of it is under some form of protection. In this study, we used spatially-explicit data on conflict, mining, and protected areas, along with a host of control variables, to estimate the impacts of these factors on forest cover loss from 1990 to 2010. Through a panel instrumental variables approach we found that: i) conflict increased forest cover loss, ii) mining concessions increased forest cover loss, but in times of conflict this impact was lessened, and iii) protected areas reduced forest cover loss, even in high conflict regions. Our results thus suggest that policy interventions designed to reduce violent conflict may have the co-benefit of reducing deforestation, especially in areas with low mining potential. Likewise, protected areas can be effective even in times of war.
Keywords
Deforestation; Protected area effectiveness; Conflict; Instrumental variables
Science of Computer Programming Volume 8, Issue 3, June 1987, Pages 231-274
Statecharts: a visual formalism for complex systems
David Harel Department of Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
Abstract
We present a broad extension of the conventional formalism of state machines and state diagrams, that is relevant to the specification and design of complex discrete-event systems, such as multi-computer real-time systems, communication protocols and digital control units. Our diagrams, which we call statecharts, extend conventional state-transition diagrams with essentially three elements, dealing, respectively, with the notions of hierarchy, concurrency and communication. These transform the language of state diagrams into a highly structured and economical description language. Statecharts are thus compact and expressive—small diagrams can express complex behavior—as well as compositional and modular. When coupled with the capabilities of computerized graphics, statecharts enable viewing the description at different levels of detail, and make even very large specifications manageable and comprehensible. In fact, we intend to demonstrate here that statecharts counter many of the objections raised against conventional state diagrams, and thus appear to render specification by diagrams an attractive and plausible approach. Statecharts can be used either as a stand-alone behavioral description or as part of a more general design methodology that deals also with the system's other aspects, such as functional decomposition and data-flow specification. We also discuss some practical experience that was gained over the last three years in applying the statechart formalism to the specification of a particularly complex system.