Resilience of river flow regimes

Abstract

Landscape and climate alterations foreshadow global-scale shifts of river flow regimes. However, a theory that identifies the range of foreseen impacts on streamflows resulting from inhomogeneous forcings and sensitivity gradients across diverse regimes is lacking. Here, we derive a measurable index embedding climate and landscape attributes (the ratio of the mean interarrival of streamflow-producing rainfall events and the mean catchment response time) that discriminates erratic regimes with enhanced intraseasonal streamflow variability from persistent regimes endowed with regular flow patterns. Theoretical and empirical data show that erratic hydrological regimes typical of rivers with low mean discharges are resilient in that they hold a reduced sensitivity to climate fluctuations. The distinction between erratic and persistent regimes provides a robust framework for characterizing the hydrology of freshwater ecosystems and improving water management strategies in times of global change.climate change | flow variability | hydroclimatic shift | water uses

Fluvial network organization imprints on microbial co-occurrence networks

“…In fluvial networks, the scaling relationship between the hydrological regime and catchment size mechanistically links fluvial network topology to biological inputs from terrestrial ecosystems into streams and to both environmental and ecological stability therein (1,29). To explore how the hydrological regime as a potential source of disturbance to benthic and microbial life in streams (29,30) changes across the Ybbs network, we adopted a probabilistic model (24,28) (Materials and Methods).…”

“…To characterize the hydrological regime of the Ybbs River network, we adopted a probabilistic characterization of temporal discharge dynamics by coupling a stochastic analysis of daily rainfall events to catchment transport dynamics (24,28). The model expresses the probabilistic structure of discharge in terms of three parameters, namely.…”

“…Fragmentation patterns were explored as a function of fluvial network hydrology, which we suitably described using a probabilistic model based on daily rainfall and streamflow (24,28) and leaning on the concept of metacommunity ecology (10).…”

“…A key question is whether the organization of microbial cooccurrence networks and their response to disturbance reflect physical characteristics inherent in fluvial networks such as geomorphology (1), resilience of the hydrological regime (24), and metacommunity dynamics (3)(4)(5)(6)(7)(8). This question is important because microorganisms, often encapsulated in biofilms attached to the streambed, fulfill critical ecosystem functions in streams and rivers (25), which have an ongoing history of being perturbed by human activity (11,26).…”

Modelling storage‐driven connectivity between landscapes and riverscapes: towards a simple framework for long‐term ecohydrological assessment

“…However, we presented this metaanalysis to simply discriminate situations which need thorough evaluation based on ecological data. Work to advance this agenda will involve a long-term analysis of annual and seasonal flow regimes in conjunction with fisheries data to examine how inter-and intra-annual flow regime variability explains variability in different components of the salmon population (Botter et al, 2013). In addition, the long-term flow modelling will be used to downscale inputs to hydraulic models for spatially distributed reaches of the river that are important habitats for key life stages where long-term observational data are available (cf Goode et al, 2013).…”