River bed stability versus clogged interstitial: Depth-dependent accumulation of substances in freshwater pearl mussel (Margaritifera margaritifera L.) habitats in Austrian streams as a function of hydromorphological parameters

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Please cite this article as: Denic, M., Tauebert, J.-E., Lange, M., Thielen, F., Scheder, C., Gumpinger, C., Geist, J.,Influence of stock origin and environmental conditions on the survival and growth of juvenile freshwater pearl mussels (Margaritifera margaritifera) in a cross-exposure experiment, Limnologica (2014), http://dx. AbstractThe freshwater pearl mussel (Margaritifera margaritifera) is a highly specialized and sensitive freshwater bivalve, whose survival in the juvenile phase is indicative of high quality habitats. This contribution investigates the use of juvenile freshwater pearl mussels as bioindicators, considering the influence of mussel stock and study stream conditions on juvenile performance, as described by survival and growth rates. A standardized cross experiment was carried out investigating juvenile performance in four different pearl mussel stocks originating from the Rhine, Danube and Elbe drainages, representing distinct genetic conservation units. The juveniles were exposed in five study streams which were selected to integrate pearl mussel streams with different water qualities and recruitment status of the mussel population. Per study stream, five standard mesh cages containing an equal number of 20 (10 x 2) juvenile pearl mussels per stock in separate chambers were installed. Survival and growth rates of juveniles were checked after three months (i.e. before their first winter) and after nine months (i.e. after their first winter). Mussel stock and study stream conditions significantly influenced juvenile performance. Growth rates were determined by study stream conditions and increased with stream water temperature, organic carbon and C/N ratios.Survival rates varied stock-specifically, indicating different levels of local adaptation to their native streams. Due to the detection of stream-specific differences in juvenile performance, freshwater pearl mussels appear suitable as bioindicators. However, a careful of consideration of stock-specificity is necessary to avoid false interpretation of bioindication results. The comparison of stock-specific survival in native versus non-native streams implicates that exposure of juveniles outside their native habitats is able to increase breeding success or else serve for risk spreading in breeding programs.

Section: Introductionmentioning

confidence: 99%

Influence of stock origin and environmental conditions on the survival and growth of juvenile freshwater pearl mussels (Margaritifera margaritifera) in a cross-exposure experiment

Denic¹,

Taeubert²,

Lange

et al. 2015

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“…Furthermore, the ingress of finer materials depletes oxygen levels in the hyporheic interstitial either through a reduction of flow-through rates or, in the case of organic particulates, by their own oxygen demand (e.g. Richards and Bacon, 1994;Scheder et al, 2015). According to Wood and Armitage (1997) sediment deposition affects benthic invertebrates in four ways: (1) by altering the substrate composition and changing the suitability of the substrate for certain taxa, (2) by increasing drift due to sediment deposition or substrate instability, (3) by affecting respiration due to the deposition of silt on respiratory structures or low oxygen concentrations associated with silt deposits, and (4) by affecting feeding activities by impeding filter feeding due to an increase in suspended sediment concentrations, reducing the food value of periphyton and reducing the density of prey items.…”

mentioning

confidence: 99%

Fine sediment deposition affects biodiversity and density of benthic macroinvertebrates: A case study in the freshwater pearl mussel river Waldaist (Upper Austria)

Leitner

Hauer

Ofenböck³

et al. 2015

a b s t r a c tFine sediment deposition in stream beds frequently generated by certain land use practices has become an increasing stressor for rivers throughout the world. In this study, the role of fine sediment deposition and its impact on the benthic macro-invertebrate assemblages was investigated in a low mountain freshwater pearl mussel stream, the Waldaist. Communities of unaffected sites and sites under high fine sediment deposition were compared. Distinct reactions of benthic assemblages in fine gravelly habitats were ascertained demonstrating a severe but still underestimated threat for invertebrate biodiversity.

“…boulder, cobble and gravel) at all surveyed sites indicates suitable substrate diversity and composition for juvenile and adult freshwater pearl mussels (Skinner et al 2003;Scheder et al 2015). However, silt was present in large proportions.…”

Section: Parametermentioning

confidence: 95%

Conservation of the freshwater pearl mussel (Margaritifera margaritifera) in the river Rede, UK: Identification of instream indicators for catchment-scale issues

Gosselin

2015

a b s t r a c tThe freshwater pearl mussel (Margaritifera margaritifera) is declining throughout its entire range. On the river Rede, North-East England, the population has been equally declining and shows no apparent recruitment. The study presented here aimed at characterizing water quality and habitat conditions for pearl mussels to identify possible indicators of pressures on the population and inform a restoration and conservation strategy. Water quality monitoring revealed levels of turbidity and suspended sediments to be above the limit set for functional pearl mussel rivers. Substrate sampling revealed silt was present at all sites. A loss of redox potential between the water column and the substrate occurred at all sites, indicating non suitable conditions for juvenile pearl mussels. These investigations suggest that fine sediment input in the river could be one of the factors preventing the development and survival of juvenile mussels while adults face water quality largely affected by high turbidity and high phosphate load. Restoration strategy for the Rede pearl mussel population should focus mainly on limiting sediment and nutrient input in the river throughout the catchment in order to improve habitat for juvenile pearl mussels. This work highlights the need for a catchment-based approach in order to succeed in the conservation of a fragile species.