The River Network Toolkit – RivTool

Abstract

Freshwater ecosystems are some of the most endangered environments in the world, being affected at multiple scales by the surrounding landscape and human activities therein. Effective research, conservation and management of these ecosystems requires integrating environmental and landscape data with hierarchic river networks by means of summarisation and synthesis of information for large and comprehensive areas at different scales (e.g. basin, sub-basin, upstream drainage area). The dendritic nature of river networks, the need to tackle multiple scales and the ever-growing sources of digital information (e.g. temperature or land use data grids) have increasingly led to hardly manageable processing time and stringent hardware requirements when integrating and working with this information. Here we present the River Network Toolkit (RivTool), a software that uses only tabular data to derive and calculate new information at multiple scales for riverine landscapes. It uses data from linear hierarchical river networks and the environmental/landscape data from their respective drainage areas. The software allows the acquisition of: 1) information that characterises river networks based on its topographic nature; 2) data obtained via mathematical calculations that account for the hierarchical and network nature of these systems; and 3) output information using different spatial data sources (e.g. climatic, land use, topologic) that result from up and downstream summarisations. This user-friendly software considers two units of analysis (segment and sub-basin) and is time effective even with large datasets. RivTool facilitates and reduces the time required for extracting information for freshwater ecosystems, and may thus contribute to increase scientific productivity, efficiency and accurateness when generating new or improving existing knowledge on large-scale patterns and processes in river networks. BackgroundFreshwater supports almost 6% of all known species though covering only 0.8% of the earth's surface and representing 0.01% of the world's water (Dudgeon et al. 2006). These ecosystems are amongst the most endangered environments worldwide (Ricciardi and Rasmussen 1999, Dudgeon et al. 2006). River systems are linked to their adjacent

The River Continuum Concept: lessons from the past and perspectives for the future

“…The awareness of such spatial and temporal complexity of riverine systems, including channel morphology, the branching structure of river networks, distance between tributary and mainstem junctions, and the shifting flow regime, has led a growing number of authors to reject the linear and predictable longitudinal changes of the RCC and support instead an idea of rivers as discontinuum-or patchy-structured systems (Townsend 1989;Bretschko 1995;Thorp et al 2006;Kiffney et al 2006;Winemiller et al 2010). This shift in framework has been strongly influenced by developments in the field of landscape ecology, as well as the growing attention toward the hierarchical structure of lotic ecosystems (Ward and Tockner 2001;Duarte et al 2019). According to this approach, which considers the spatial and temporal dynamics of lotic ecosystems, the river network can be seen as a mosaic of different patches, typically defined as geomorphological units (Datry et al 2016a), and the distribution of aquatic taxa can be predicted as a function of the spatial and temporal availability of these patches (Montgomery 1999).…”

Assessing the Connectivity of Riparian Forests across a Gradient of Human Disturbance: The Potential of Copernicus “Riparian Zones” in Two Hydroregions

“…We validated the site selection to ensure that all river segments share similar geomorphological and climatic features in each hydroregion (Table 1). An analysis of similarities (ANOSIM) based on Euclidean distances was performed, with variables extracted from the CCM2 database, using the River Network Toolkit software (RivTool) [28]. No significant differences were found between catchments within each hydroregion (Global R ANOSIM for the Mediterranean hydroregion = 0.58, p = 0.0001; Global R ANOSIM for the Central Baltic hydroregion = 0.65; p = 0.0064).…”

“…The former represents the number of existing large dams restraining water flow in the upstream drainage area of each SU, and the latter the capacity of those dams to function as reservoirs. These catchment-scale variables were obtained using RivTool [28] and were derived from georeferencing large dams included in the ICOLD database [30]. For the segment scale, we computed the Number of Barriers (S_BAR) by visually identifying the number of weirs and barriers that were affecting water flow along each river segment over the Esri World Imagery layer.…”

Generation and application of river network analogues for use in ecology and evolution

“…An understanding of many of these processes requires a spatially explicit approach, such as how pollution and chemicals are transported in riverine networks [Helton et al, 2018], how organisms spread along rivers and invade riverine ecosystems [Mari et al, 2014;Giometto et al, 2017], or how the modification of network structures across drainage basins affects local diversity [Leuven et al, 2009]. Consequently, there has been a rapid increase in ecological and evolutionary studies considering the effect of river-like network structures on ecological dynamics over the last two decades [Fagan, 2002;Campbell Grant et al, 2007], paralleled by an increase in methodological tools to analyse such spatial datasets [Muneepeerakul et al, 2008;Rodriguez-Iturbe et al, 2009;Peterson et al, 2013;Welty et al, 2015;Duarte et al, 2019;Rinaldo et al, 2020].…”