The response of perennial and temporary headwater stream invertebrate communities to hydrological extremes

Abstract

The headwaters of karst rivers experience 10 considerable hydrological variability, including 11 spates and streambed drying. Extreme summer 12 flooding on the River Lathkill (Derbyshire, UK) 13 provided the opportunity to examine the invertebrate 14 community response to unseasonal spate flows, flow. 15 recession and, at temporary sites, streambed drying. 16 Invertebrates were sampled at sites with differing 17 flow permanence regimes during and after the spates. 18 Following streambed drying at temporary sites, AlElectronic supplementary material The online version of A2 this article

Fine sediment reduces vertical migrations of Gammarus pulex (Crustacea: Amphipoda) in response to surface water loss

“…As the volume of fine sediment within the gravel matrix increased, the proportion of individuals moving into the bed during dewatering declined, while the number stranded on the substrate surface increased. These different responses to surface water loss, which are attributed to sediment characteristics, indicate why gammarids may become stranded on drying sediments (Extence, 1981;Richardson et al 2002;Stubbington et al, 2009) despite being a mobile taxon capable of inhabiting subsurface habitats (Dole-Olivier et al, 1997;Wood et al, 2010).…”

“…In particular, the occurrence of fine sediment within substrate interstices may reduce invertebrate density and diversity (Angradi, 1999;Matthaei et al, 2006) and limit invertebrate movement into and use of subsurface sediments (Navel et al, 2010;Descloux et al, 2013). Substrate size, porosity and permeability evidently influence faunal movements through interstitial spaces (Fowler & Death, 2001;Descloux et al, 2013), and where invertebrates are unable to enter interstices, they become stranded on the riverbed and may be exposed to adverse conditions such as emersion during streambed drying (Perry & Perry, 1986;Stubbington et al, 2009).…”

Is the hyporheic zone a refugium for aquatic macroinvertebrates during severe low flow conditions?

“…This evidence appears to have been largely overlooked in the following years until freshwater scientists began to explore the vertical distribution of fauna within river beds (Coleman & Hynes 1970) leading to the 'hyporheic refuge hypothesis' proposed by Williams & Hynes (1974). Since then, the role of the hyporheic zone as a potential refugium has received increasing attention, with a particular emphasis on hydrological extremes associated with fl oods and droughts (Palmer et al 1992, Marchant 1995, Dole-Olivier et al 1997, Stubbington et al 2009a, Robertson & Wood 2010.…”

“…The response of benthic fauna to fl oods and droughts has been studied in detail (e.g., Lake 2000, Suren & Jowett 2006, Stubbington et al 2009a) although the availability of long-term baseline data prior to individual events often limits the ability to accurately gauge the full extent of community change or recovery processes (Lake 2003, Bêche et al 2009). Numerous studies have examined benthic faunal use of the hyporheic zone as a result of increased discharge and fl oods, and while some do support the hyporheic refuge hypothesis (Puig et al 1990, Dole-Olivier & Marmonier 1992, Marchant 1995, an almost equal number report limited or no evidence (Palmer et al 1992, Olsen & Townsend 2005.…”

Effect of Flow Fluctuations on Patch Dynamics and Chironomid Distribution in a Medium-Sized Lowland River

“…A high abundance of Orthocladiinae, mainly at the riffle habitat of the Drzewiczka River, was due to Cricotopus spp., which is the most eurytopic genus of this subfamily (Cranston et al 1983, Gnybkowska andDukowska 2002) and may be distributed along the river continuum (Lindegaard and Brodersen 1995). On the basis of the current study, this taxon may also be characterized by a high ability to tolerate disturbance (resistance sensu Stubbington et al 2009). …”