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Abundancia, distribuciòn longitudinal y movilidad de large woods en cuencas de la Cordillera de la Costa, Chile.
No full textLarge wood load fluctuations in an Andean basin
No full textThe importance of monitoring and analysing wood fluxes in mountain environments is widely recognized. However, there is a lack of information related to the long-term fluctuations in wood load and associated to the changes in large wood (LW) characteristics. The main aims of the research were to analyse (i) changes in wood characteristics, (ii) fluctuations in wood load, and (iii) the relationship between wood load and sub-reach settings, proposing an ad hoc roughness index (RI). Repeated field surveys to measure wood load and LW characteristics during a 13-year period were conducted within a 2.2 km-long reach of the Rio Toro (Chile), which flows through the Malleco Forest National Reserve that was affected by wildfires in 2002 and 2015. Two spatial scales (i.e. study reach and sub-reach) were considered. Irrespective of the adopted scale wood load fluctuated considerably, in both number and volume, with significant changes in LW characteristics (i.e. mean diameter and length). Moreover, a clear tendency to the aggregation in wood jams (WJs) was observed within the entire study reach. Based on our results, we conclude that 17 years after the first wildfire wood recruitment has started in the upper parts of the basin. Moreover, Generalized Linear Mixed Models (GLMM) analyses were carried out to investigate the relationship between RI and both number and volume of LW. Both models are characterized by high adjusted R2 of 74.9% and 72.8% for volume and number, respectively. This demonstrated that the RI can characterize the reaches in terms of tendency to deposition and trapping of wood. These results are promising, particularly in improving the knowledge related to potential deposition areas that can control wood load fluctuations, also permitting its management to be improved. © 2020 John Wiley & Sons, Ltd
In-channel large woods in two natural forested mountain catchments in Southern Chile: abundance, mobility, flow resistance and hydro-morphological efects analysis.
No full textField based analysis of sediment entrainment in two high gradient streams located in Alpine and Andine environments.
No full textGeomorphic Effect of Wood in Southern Andes Streams: Evidences From Three Mountain Basins.
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The role of in-channel vegetation in driving and controlling the geomorphic changes along a gravel-bed river
Full text linkGravel-bed rivers are fluvial systems featuring highly complex morphological and evolutionary patterns because
of their configuration characterized by the contemporary presence of many distinct morphological units.
Complexity can also be observed in the response of gravel-bed rivers to flow conditions, which can be highly
varied. This work aims to analyze the evolution of gravel and vegetated areas in a gravel-bed river during a
period of persistent low flow conditions, focusing also on the responses exhibited by the different types of riparian
vegetation. To this end, a 2200 m-long segment of the Piave River (NE Italy) was considered. It was
surveyed twice by LiDAR (August 2003 and August 2010), permitting the analysis of the spatial-temporal evolution
of gravel and vegetated areas through both cover type analysis and the DoD technique. During the study
period (August 2003 – August 2010), the flow conditions were constantly ordinary, i.e., under-bankfull. The
cover type analysis stressed an increase of +115 % in vegetated areas, which have diffusely colonized the river
corridor. However, the low flow conditions also induced geomorphic changes with 54 % of the study area
affected by variations in surface elevation. The DoD computed a diffuse deposition over the main and secondary
channels, while erosion was observed in specific areas of the main fluvial island and along the right floodplain. In
terms of vegetation changes, five eroded patches were identified, which contributed to 60 % of the vegetated
area entirely eroded in the study reach. These patches were mainly characterized by mature vegetation taller
than the mean vegetation height observed over the study reach. Therefore, the analysis of the response of the
Piave River to persistent under-bankfull flows stressed a complex evolution of the gravel and vegetated areas,
which can be appreciated also because of low flow conditions, emphasizing the composite dynamics typical of a
gravel-bed river. These results could improve riverine management considering vegetation structure and
dimension, as well as the geomorphic settings of gravel-bed rivers in view of future low flow conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluaciòn de los volùmenes y de los efectos hidro-morfològicos de los detritos lenosos en dos torrente Andinos (Chile)
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