Response of invertebrates to lotic disturbance: a test of the hyporheic refuge hypothesis

Abstract

Recovery following hydrological disturbances is usually rapid for lotic invertebrates. Stream ecologists have assumed that recovery is facilitated by behavioral migrations during floods down into the hyporheic zone (the interstitial spaces of a streambed) to seek temporary refuge from possible erosion (the "hyporheic refuge hypothesis"). We provide the first explicit test of this hypothesis by evaluating three predictions of the hypothesis. We coupled field observations of the response of meiofaunal invertebrates to floods with field and flume experiments. The study site was a sandy-bottom stream in northern Virginia. Prediction 1, that loss of fauna from a streambed during floods should be minimal as long as the depth of scour in the streambed is less than the depth of the hyporheic zone, was not supported for any taxon. For two floods which varied considerably in magnitude, 50-90% of the fauna was lost from the bed despite the fact that the depth of scour (10-30 cm) was significantly less than the total depth of the hyporheic zone (50 cm). Prediction 2, that fauna should move deeper into the bed at higher flows, was supported by field observations during only one of two floods and then only for rotifers. In flume experiments that tested for finer scale behavioral movements, significant vertical migrations were found for copepods and chironomids which moved 1.5-3.5 cm downward as mean velocity (3 cm off bottom) was increased from 5-23 cm/s. Movements down by rotifers were not found in the flume experiments. Prediction 3, that the hyporheic zone is the most important source of colonists to defaunated areas, was supported in part by field experiments. The hyporheic route was not the primary route for any taxon but it was as important for the rotifers and copepods as water column or streambed surface routes. We conclude that, even though smallscale (cm's) migrations into the streambed in response to increased flow may be observed for some taxa and the hyporheic zone may serve as a partial source of colonists following disturbances, movements down are not adequate in preventing significant losses of meiofauna during floods.

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

“…Evidence of benthos uti- Mixed (boulder, cobble, gravel and fi nes < 2 mm) eschweizerbart_xxx lisation of the hyporheic zone in perennial rivers and streams as a result of increased fl ows (spates/fl oods) is also equivocal (e.g., Palmer et al 1992, Dole-Olivier et al 1997, Fowler & Death 2001, Olsen & Townsend 2005, Olsen et al 2010. A number of studies have reported increased abundances of benthos within the hyporheic zone following spates, but also that the response was variable spatially (Dole-Olivier & Marmonier 1992, Dole-Olivier et al 1997.…”

“…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.…”

Modificación de ambientes lóticos para la extracción de carbón a cielo abierto: efectos sobre la biota y recomendaciones

“…Aunque los organismos acuáticos exhiben algún grado de resiliencia al disturbio (Palmer et al, 1992) también son susceptibles a alteraciones del hábitat (Gorman y Karr, 1978;Pretty et al, 2003). Alteraciones como la canalización, desvío y represamiento de los cauces pueden afectar de diversas formas el hábitat de la biota acuática (Fig.…”

Peuplement des Crustacés dans la zone hyporhéique d'un ruisseau des Pyrénées

“…Toutefois, Giberson & Hall (1988) n'observent pas de variations saisonnières des invertébrés autres que les insectes dans un cours d'eau canadien ; Kowarc (1991) La persistance observée sur le Nert implique donc que la communauté des Crustacés de ce site n'est pas influencée par les perturbations de l'environnement. Parmi ces dernières, les crues sont considé-rées comme un des facteurs essentiels de déstabili-sation du milieu hyporhéique (Williams & Hynes 1974, Danielopol 1976, Marmonier & Dolé 1986, Marmonier 1988, Strommer & Smock 1989 Dole et Marmonier 1992, Palmer 1990, Palmer et al 1992. Sur le Nert, lors de l'année étudiée, comme sur le Lachein (Rouch 1988), les crues n'ont modifié ni la morphologie du lit, ni la structure globale des écou-lements interstitiels (Rouch 1992, Rouch et al sous presse) ni la structure des peuplements.…”