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Water, sediment, and large wood (LW) are the three key components of dynamic river-floodplain ecosystems. We examined variations in sediment and LW discharge with respect to precipitation, the presence of dams, land and river use change, and related channel incision and forest expansion on gravel bars and floodplains across Japan. The results indicated that unit sediment discharge and unit LW discharge were smaller in southern Japan where precipitation intensity is generally much greater. Effective precipitation, an index that takes current and antecedent precipitation into account, was a strong predictor of discharge in small watersheds, but not in larger watersheds. However, precipitation intensities related to unit sediment discharge in intermediate and large watersheds were smaller than those associated with unit LW discharge, which we attribute to differences in particle shape and size and also transport mechanisms. The relationship between river flow and discharge of sediment and LW lead us to posit that discharges of these components are supply limited in southern Japan and transport limited in northern Japan. The cross-sectional mean low-flow bed elevation of gravel-bed and sand-bed rivers in Japan decreased by similar to 0.71 and 0.74 m on average, respectively, over the period 1960-2000. Forest expansion on bars and floodplains has been prominent since the 1990s, and trees apparently began to colonize gravel bars similar to 10 to 20 years after riverbed degradation began. Forest recovery in headwater basins, dam construction, gravel mining, and channelization over the past half century are likely the dominant factors that significantly reduced downstream sediment delivery, thereby promoting channel incision and forest expansion. Changes in rivers and floodplains associated with channel incision and forest expansion alter the assemblages of aquatic and terrestrial organisms in riverine landscapes of Japan, and climate change may contribute to this change by intensified precipitation. Additionally, regime shifts of water, sediment, and LW may continue or they may reach a dynamic state of quasi-equilibrium in the future. Continued monitoring of these three components, taking into account their geographic variation, is critical for anticipating and managing future changes in river-floodplain systems in Japan and around the world. (C) 2016 Elsevier B.V. All rights reserved.

Understanding patterns of natural forest expansion in rural regions under the influence of urbanization processes is crucial for integrated spatial planning across the urban-to-rural gradient. As a matter of fact, forest expansion is the only natural process that may counteract the consumption of the ecosystem capital and ecosystems services of rural lands due to uncontrolled urban sprawl. The paper addresses this topic in the paradigmatic case study of the countryside of Rome (Italy), characterized by counter dynamics of forest expansion and suburbanization. Morphological Spatial Pattern Analysis (MSPA) is applied to classify the forest landscape structure twice (1974 and 2008) according to seven categories (core, islet, perforation, edge, loop, bridge, branch) with different potential functional role as elements of a green infrastructure. Main findings are: (i) forest cover increased from 11% to 16% between 1974 and 2008; forest land uptake exceeds 4% of total study area, but shows a slower pace than the growth of built-up areas (10%); (ii) forest expansion has been to a large extent achieved by “sprawling” of islets (1.6% of the study area) along the stream network; (iii) more compact forest expansion has taken place on 0.2% of the study area in the form of additions to existing core areas or creation of new ones and (iv) the establishment of a network of protected areas nearby Rome has played a key role for the conservation and further expansion of core areas; yet, local loss of 1974 core areas stocks in a few protected areas indicates need of further law enforcement to ensure effective protection of the natural capital from degradation processes or even land conversion into built-up areas. Results calls for future in-depth investigations on the quality of newly created or maintained forest resource stocks associated to different spatial pattern structures. Integrated spatial planning strategies are outlined for the conservation of ecosystem capital and ecosystems services provided by forests, as major components of Rome’s green infrastructure. L'articolo è disponibile sul sito dell'editore www.elsevier.com