In RO4929097 addition to a tradition of explicitly identifying thresholds, geomorphology has established conceptual frameworks for considering scenarios in which thresholds are not crossed, as well as the manner in which a system can respond once a threshold is crossed. Relevant geomorphic conceptual frameworks include static,

steady-state and dynamic equilibrium (Chorley and Kennedy, 1971 and Schumm, 1977), disequilibrium (Tooth, 2000), steady-state versus transient landscapes (Attal et al., 2008), complex response (Schumm and Parker, 1973), lag time (Howard, 1982 and Wohl, 2010), and transient versus persistent landforms (Brunsden and Thornes, 1979).

I propose that geomorphologists Selleckchem GW572016 can effectively contribute to quantifying, predicting, and manipulating critical zone integrity by focusing on connectivity, inequality and thresholds. Specifically, for connectivity, inequality and thresholds, we can provide three services. First, geomorphologists can identify the existence and characteristics of these phenomena. What forms of connectivity exist between a landform such as a river segment and the greater environment, for example? What are the spatial (magnitude, extent) and temporal (frequency, duration) qualities of this connectivity? Where and when do inequalities occur in the landscape – where does most sediment come from and when is most sediment transported? What are the thresholds in fluxes of water, cAMP sediment, or solutes that will cause the river to change in form or stability? Second, geomorphologists can quantify changes in connectivity, inequality or the crossing of thresholds that have resulted from past

human manipulations and predict changes that are likely to result from future manipulations. How do human activities alter fluxes, and how do human societies respond to these altered fluxes? To continue the river example, how did construction of this dam alter longitudinal, lateral, and vertical connectivity on this river? How did altered connectivity change the distribution of hot spots for biogeochemical reactions in the riparian zone or around instream structures such as logjams? How did altered connectivity result in changed sediment supply and river metamorphosis from a braided to a single-thread river, as well as local extinction of fish species? Third, geomorphologists can recommend actions to restore desired levels of connectivity and inequality, as well as actions that can be taken to either prevent crossing of a negative threshold that results in undesirable conditions, or force crossing of a positive threshold that results in desirable conditions.