Riverine landscapes: Biodiversity patterns, disturbance regimes, and aquatic conservation

“Water from the streams brings huge amount of nutrient and sediments and renews the water of the wetlands; it stimulates the biological responses in the wetlands (Ward 1998; Junk et al.”

“In fish assemblages, the association between richness and diversity and alteration of variability in both average flow magnitude (MA22 and MA36) and high flow frequency, (FH2) is supported by studies relating hydrologic variation to North American stream fishes (Ward, 1998; Niu et al., 2012, but see McGarvey, 2014).”

“Bledsoe, & Cuhaciyan, 2006), as systems influenced by the landscape through which they flow (Fausch, Torgersen, Baxter, & Li, 2002; Townsend, Doledec, Norris, Peacock, & Arbuckle, 2003), and as river landscapes of their own (Robinson, Tockner, & Ward, 2002; Ward, 1998).”

“Patches, which are largely created by disturbance agents including flow and sediment dynamics (Ward, 1998), may in turn influence population growth, foraging patterns, competition, and trophic dynamics of riparian consumers (Wiens, 1976; Mangel and Clark, 1986) via multiple mechanisms including…”

“As the need to protect freshwater biodiversity becomes greater due to large-scale environmental change, the need to understand these systems at multiple scales increases (Ward 1998).”

“…process that enhances the exchange of moisture, sediments and nutrients between the river channel and the river–floodplain ecosystems and in the process maintains the connectivity between these river ecosystem components (Ward, 1998; Petts, 1999; Bunn and Arthington, 2002; Thoms et al., 2005).”

“Moreover, our study implicitly supports the idea that action plans should be designed at a landscape scale (Ward, 1998).”

“In the middle reaches, by contrast, light and nutrient levels are higher, water is clearer, substrate is often patchy and thermal variance is maximal (Ward, 1998).”

“The mosaic is created through dynamic river-floodplain interactions, including geomorphic processes that erode and deposit sediment (Ward 1998), which produce the physical template for ecosystem development (the focus of this model) and processes that occur during subsequent inundations (the focus…”

“There is international concern for the loss of biodiversity (Suter, 1998; Ward, 1998; Cabeza and Moilanen, 2006; Garden et al., 2006), particularly due to habitat fragmentation (Buxton et al.”

“It is well established that lotic environments especially rivers are highly speciose and contain a disproportionate amount of biodiversity given their relatively small proportion of the worldwide landscape (Sheldon 1988; Allan and Flecker 1993; Ward 1998; Dudgeon et al. 2006; Tedesco et al. 2017).”

“These pressures deeply affect the natural environmental heterogeneity of riverbank environments, causing considerable damage to both the levels of biodiversity and to ecological processes (Strayer et al., 2003; Townsend, Doledec, Norris, Peacock, & Arbuckle, 2003; Ward, 1998).”

“IntRoductIon Human interference in the structure of river channels through var-ious types of regulation works, as well as exploitation of gravel material, has led to vast degradation of riparian environments, currently affecting over 90% of rivers in Europe (1, 2, 3, 4).”

“…of a river play an important role in the maintenance of a high level of environmental heterogeneity and biological diversity across space and time (Ward 1998; Ward and Tockner 2001; Tockner and Stanford 2002; Junk 2005), and lead to various modes of adaptation by flora and fauna to natural flow…”

“Ward [ 53 ] emphasizes that the river channel accounts for only a part of the extensive interacting complexes of biotopes and natural gradients that, together with corresponding biotic communities, form lotic ecosystems.”

“Associée à une forte dynamique naturelle des zones riveraines, cette complexité structurale s’accompagne d’une diversité spécifique et fonctionnelle élevée [40].”

“Within a floodplain complex there is a mosaic of wetlands that vary in morphology, hydrology and water quality characteristics that create a heterogeneity of aquatic habitat in floodplains and consequently, high biological diversity (Ward, 1998; Nielsen and Brock, 2009).”

“Many plant species in floodplain forests have adapted to the occasional strong disturbance of removing (harvesting) the tree layer (Wenger et al. 1990; Ward 1998).”

“Floodplains are home to riparian habitat which can serve as important corridors and sanctuaries for terrestrial species and serve as food sources and habitat for aquatic species [20, 21, 22].”

“Previous studies revealed that moderate hydrological disturbance resulted in the highest biological diversity [38,39].”

“River corridors have been recognized as linear landscapes in which water flow plays a key role in connecting various landscape patches (Junk et al., 1989; Malanson, 1993; Ward, 1998).”

“2007), because riparian ecosystems are formed by interactions between erosive flooding and terrestrialization processes (Ward 1998; Ward and Tockner 2001).”

“Spatial variability of inundation during events of a given magnitude and frequency can influence the spatial arrangement of trees on a floodplain (Hupp & Osterkamp, 1996; Hupp & Rinaldi, 2007; Nilsson & Svedmark, 2002; Ward, 1998).”

“For example, the input of allochthonous sediments in streams and the impairment of the chemical and physical integrity of the aquatic habitat may be correlated to the lack of riparian vegetation and intense land use in the watershed (Ward, 1998; Wiens, 2002; Casatti et al., 2006; Cunha et al., 2019).”

“…species richness is generally consistent with well-supported understanding of stream biodiversity (Vannote et al., 1980; Oberdoff et al., 1995; Ward, 1998; Muneepeerakul et al., 2008; Carrara et al., 2012; Altermatt, 2013) as well as empirical data covering individual river networks (e.g.,…”

“The connection between terrestrial and aquatic ecosystems and how aquatic environments respond to peripheral influences is a major paradigm within aquatic ecology (Ward, 1998).”

“…Science Western Switzerland, Route de Presinge 150, 1254 Jussy, Switzerland munity composition in riparian habitats, because of the temporal and spatial variability of flood and drought (Walker et al. 1995; Hughes 1997; Poff et al. 1997; Richter et al. 1997; Ward 1998; Nilsson and Svedmark 2002).”

“Some studies have already shown the negative role that these environmental events cause on diversity and the structuring of benthic macroinvertebrate freshwater assemblages (Flecker and Feifarek 1994, Ward 1998).”

“Exchanges of water between rivers and their floodplains via overbank inundation, as well as through the hyporheic zone, play important roles in driving habitat heterogeneity including, for example, variability in shallow groundwater levels (Ward 1998; Gowing et al.”

“Species loss due to environmental changes is problematic in aquatic ecosystems (e.g., Ward, 1998; Lepori and Hjerdt, 2006).”

“Natural flood disturbances are an integral component of active floodplain ecosystems (Ward 1998).”

“According to Ward (1998), the riverine ecosystem should be considered in four dimensions, including lateral connections and temporal dynamics.”

“Riverscape was then introduced into fluvial ecology as a new holistic research perspective (Schlosser 1991; Ward 1998; Fausch et al. 2002), and this new continuous view was initially used to study aquatic biota dynamics and then integrated into the management of fish resources and fluvial…”

“Natural riverine landscapes (riverscapes hereafter) maintain connectivity across four dimensions, including longitudinal (upstream to downstream), lateral (main channels to floodplains), vertical (groundwater to surface water), and temporal (flow variability through time; Ward, 1998).”

“Among them, 11 species of the genus Bembidion predominate, as also noted by other researchers [3 ,68,69].”

“Most large rivers of Europe and Central Asia have suffered from flow regulation and human activities (Dynesius and Nilsson 1994; Ward 1998), and temporary pools have disappeared dramatically as a result of agriculture intensification and urbanization (Bouahim et al. 2014).”

“High physio-chemical heterogeneity may exist within the same waterbody, providing complex and diverse habitats for freshwater fauna (Thomaz et al. 2007; Ward 1998).”

“The construction of water infrastructure and associated impoundment of riverine habitat has been shown to decrease the abundance of many aquatic species (Abromovitz 1996; Ward 1998; Tucker 2000; Tucker et al. 2012).”

“Demands for groundwater are ever‐increasing in water‐limited regions (Feng et al., 2013; Oki & Kanae, 2006; Vörösmarty, Green, Salisbury, & Lammers, 2000; Ward, 1998).”

“…stages and later successional stages that is valuable from a landscape diversity point of view (Amoros and Bornette 2002, Naiman et al. 1993, Osterkamp et al. 2001, Schnitzler 1996, Ward 1998, Ward et al. 1999) will not be perpetuated under the prevailing hydrologic and geomorphologic regimes.”

“But flow is only one of many factors that interact to determine the physical and biological attributes of healthy rivers (Ward 1998, Saunders et al. 2002), and many of these factors are strongly dependent on the status of upstream tributaries (Meyer and Wallace 2001) and on linkages between…”

“These small tributaries and their integral riparian environments are hotspots for watershed faunal diversity (e.g., Naiman & Decamps, 1997; Ward, 1998; Ward & Tochner, 2001; Fernandes et al., 2004; Sabo et al., 2005).”

“The literature on river ecosystems is extensive (Huet, 1949; Illies, 1961; Vannote et al ., 1980; Ward, 1989, 1998; Calow & Petts, 1994; Ward & Stanford, 1995; Bloesch, 1997).”

“For instance, the notion that habitat heterogeneity creates diverse (Hutchisonian) niches and, as a result, contributes to maintaining biodiversity is a central tenet of conservation (e.g., Stein et al., 2014; Ward, 1998).”

“These “riverine landscapes” (hereafter riverscapes) possess their own inherent properties, processes, and dimensions that vary across time and space (Ward 1998).”

“Conceptually, riverscapes represent freshwaters running through landscapes (Fausch et al., 2002; Ward, 1998; Wiens, 2002) as highly confined, linear and hierarchical stream networks (Benda et al., 2004; Fausch et al., 2002; Humphries et al., 2014; Montgomery, 1999; Ward, 1998).”

“…understanding is recognising two key features that underpin the heterogeneity of riverine landscapes: (1) the interplay between hydrology, geomorphology and ecology in space and through time; and (2) the hierarchical way in which rivers function (Wu and Loucks 1995; Ward 1998; Dollar et al. 2007).”

“However, all are very important for different aspects of biodiversity [4] and as connecting elements.”

“Factors affecting herb biodiversity include migration and invasion (Barrat-Segretain 1996), disturbance (Day et al. 1988; Ward 1998), water supply (Bruner 1931; Hughes 1988), temperature (Naiman and Décamps 1997) and nutrients (Grévilliot et al. 1998).”

“2003) and the resultant habitat heterogeneity contributes to riverine taxonomic richness (Ward 1998).”