Indices of connectivity are critical means for moving from qualitative to (semi-)quantitative evaluations of material (e.g., water, sediment and nutrients) transfer across the building blocks of a terrestrial system. In geomorphology, compared to closely related disciplines like ecology and hydrology, the development of indices has only recently started and as such presents opportunities and challenges that merit attention. In this paper, we review existing indices of sediment connectivity and suggest potential avenues of development for meeting current basic and applied research needs. Specifically, we focus on terrestrial geomorphic systems dominated by processes that are driven by hydro-meteorological forcing, neglecting seismically triggered events, karstic systems and environments controlled by eolian processes. We begin by setting a conceptual framework that combines external forcings (drivers) and system (intrinsic) structural and functional properties relevant to sediment connectivity. This framework guides our review of response variables suitable for sediment connectivity indices. In particular, we consider three sample applications concerned with sediment connectivity in: (i) soil studies at the plot scale, (ii) bedload transport at the reach scale, and (iii) sediment budgets at the catchment scale. In relation to the set of response variables identified, we consider data availability and issues of data acquisition for use in indices of sediment connectivity. We classify currently available indices in raster based, object or network based, and indices based on effective catchment area. Virtually all existing indices address the degree of static, structural connectivity only, with limited attention for process-based, functional connectivity counterparts.

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[1] In glaciated British Columbia, Canada, Quaternary climate changes are responsible for profound spatial reorganization of Earth surface processes. These changes have left a landscape characterized by topographic anisotropy associated with a hierarchy of glacial troughs. The evolution of glaciated landscapes is examined by analyzing the structure of geomorphic process domains and channel long profiles. To identify process domains we use channel surveys and GIS analysis to construct slope-area transects of the channel network. This analysis reveals generalized process-form disequilibrium with a mismatch between topographic signatures and currently active geomorphic process domains. At the landscape scale of ''source'' colluvial channels (contributing area <1 km 2 ), the glacial/paraglacial signature commonly overrides that produced by contemporary debris flows. Along the axis of former ice flows, relict glacial cirques introduce a ''hanging'' fluvial domain at contributing areas as small as 8 Â 10 À2 km 2 and produce complex channel long profiles similar to those observed for rivers responding to tectonic forcing. Slope-area relations typical of unglaciated equilibrium environments do not apply here. The concept of process domains appears to hold, however, some major glacially forced modifications in the alluvial-colluvial transition are observed and the definition of a depositional colluvial subdomain is proposed. Comparison between field-and GIS-measured slopes reveals that GIS-associated error is not uniform between process domains, and that GIS-based plots do not successfully discriminate field-based process domains. The combination of glacial and post-glacial fingerprints and the effects of ongoing Earth surface processes generate a complex landscape whose glacial signatures may persist until the onset of the next ice age.Citation: Brardinoni, F., and M. A. Hassan (2006), Glacial erosion, evolution of river long profiles, and the organization of process domains in mountain drainage basins of coastal British Columbia,

We use magnitude-frequency analysis as a statistical tool to quantify the erosion caused by landslides and debris flows. Using air-photo-and ground-derived data we show that the departure from power-law distribution customarily observed for small magnitude is an artefact of sampling deficiencies. Nonetheless, the total distribution is not sensitive to the frequency of small slides and total erosion remains adequately represented in the air-photo-derived data. Our data also demonstrate a real departure from simple scaling at much larger magnitudes, the cause of which is not definitively established. Copyright

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