Beyond desertification: new paradigms for dryland landscapes

www.frontiersinecology.org © The Ecological Society of America C to existing paradigms – the set of practices or universally recognized achievements or perspectives that define a scientific discipline at any particular period of time – are fundamental to the progress of scientific knowledge (Kuhn 1962). While these challenges have always been part of science, the frequency and number of successful challenges to traditional paradigms across many ecosystem types may be higher now than at any time in the past (eg Naeem 2002). Innovative knowledgegenerating technologies acting in concert with new forms of communication among scientific disciplines are leading to a more complete understanding of Earth as a coupled human–natural–physical system operating at multiple, interacting scales. This new information and deeper understanding drives paradigm shifts in numerous ecological subdisciplines, by identifying shortcomings – including inconsistencies – that must be addressed and resolved. Advances in sensor technologies – as well as improvements in modeling, sample analysis methodologies such as genome sequencing (Cohen et al. 2009; Porter et al. 2009; Luo et al. 2011), and data management – are increasing the spatiotemporal extent and resolution of studies while facilitating access to and analysis of large datasets (Peters 2010; Michener and Jones 2012). The spatial scale for observing underlying mechanisms has progressed from individualor plot-scale studies to examinations conducted at much finer scales (eg point-based sensors, cellular-level micro-arrays); at the same time, airborne and space-based imagery allow for integration of this information at broader (regional to global) scales (eg Hasselquist et al. 2010; Ponce-Campos et al. 2013). Likewise, shortterm fluctuations can now be distinguished quantitatively from long-term directional changes through the availability of instruments measuring and data/proxies covering short (near real-time), medium (decades to centuries), and long (paleo records) time frames (Jackson 2001; Moran et al. 2008; Porter et al. 2009). By expanding the depth and breadth of scientists’ scales of study, such innovations have enabled paradigms associated with various levels of biological organization, from genes to the biosphere, to be challenged (Jones et al. 2006). Accordingly, equilibrium views that predominated until the mid-20th century have been replaced by perspectives accounting for non-equilibrium dynamics that include linear and non-linear behaviors with thresholds, bifurcation points, alternative states, regime shifts, tipSHIFTING PARADIGMS IN DRYLANDS