Alpine river ecosystem response to glacial and anthropogenic flow pulses

Alpine glacier-fed river hydrology, chemistry and biology can vary significantly both in space and over diurnal to inter-annual timescales, as a function of dynamic inputs of water from snow, ice and groundwater. The sensitivity of biota to these water source dynamics potentially makes them susceptible to hydrological changes induced by anthropogenic activities, such as flow regulation, but most alpine studies have focused on intact rivers and during summer only. We examined the patiotemporal dynamics of physicochemical habitat and macroinvertebrate communities in a high (>2000m) altitude floodplain in the European Alps over an 18 month period. A novel insight is presented into the river system and macroinvertebrate community responses to both natural glacier melt driven expansion-contraction of unregulated river sites, and intermittent flow pulses due to hydropower regulation. Mainstem glacier-fed river sites displayed cyclical seasonal dynamics in macroinvertebrate community composition, shifting to be partly reminiscent of groundwater tributaries in winter then back to meltwater again in the following spring. Significant unimodal relationships were observed between glacial influence and macroinvertebrate community density, richness, Simpson's diversity, evenness and beta diversity. These relationships suggest that glacial influence can have positive effects on biodiversity where glacier meltwater mixes with non-glacial water and habitat diversity is maximised. Regulationinduced flow pulses led to inconsistent responses amongst macroinvertebrates, with no significant effects in summer 2008 but increased density and decreased taxonomic richness in 2009. Furthermore, macroinvertebrate community composition was not affected significantly by reservoir releases despite significant increases in water temperature and discharge at these times. The effects of alpine river management for hydropower production on macroinvertebrate communities in this river system appear to be relatively minor, but further studies need to be undertaken in other alpine locations to assess the generality of this finding

HOW TO FIND A STONE CRAYFISH AUSTROPOTAMOBIUS TORRENTIUM (SCHRANK, 1803): A BIOGEOGRAPHIC STUDY IN EUROPE

The stone crayfish Austropotamobius torrentium (Schrank, 1803) is widely distributed in Southeastern and Central Europe. However, this information has not been verified until recently because of: • ignorance about biogeographic notion and hydrography and • ignorance of data in the literature. Overcoming these problems during the last decade, the distribution pattern of the stone crayfish has now become apparent in Europe. It is known from Luxembourg and Germany to the west, from Turkey to the east, from Germany and the Czech Republic to the north and from Greece to the south. It is absent in the northeastern part of the Pannonian basin as well as in Poland and Ukraine. Its presence in Luxembourg and the Czech Republic may be related not to natural distribution but to introduction by humans through history. The discovery of the stone crayfish in Italy and Turkey as well as its re-discovery in France during the 1990s proves the biogeographic conception that this animal belongs to the Danubian fauna. It probably originates from the southwestern part of the Pannonian basin

Freshwater crayfish in South Tyrol (Italy): Distribution and protection measures of endangered Austropotamobius pallipes

Freshwater crayfish are among the most endangered animals in Europe. Information on freshwater crayfish in the Italian province of South Tyrol was insufficient until the recent studies on their historical and present distribution, which showed the alarming facts that only 15 standing and running waters remained as freshwater crayfish habitats, carrying the native Austropotamobius pallipes and the allochthonous Astacus astacus, Orconectes limosus, and Pacifastacus leniusculus. Still ongoing alterations or degradation of water bodies have contributed to the high degree of population decline and loss. While the exotic crayfish O. limosus and P. leniusculus could develop higher densities, most of the autochthonous A. pallipes populations were weak and consisted only of a few individuals. Three populations of A. pallipes, however, remained in a good condition, representing potential sources for recovery programs. Protection measures currently carried out in South Tyrol involve breeding, restocking and reintroduction of autochthonous A. pallipes individuals in ecological intact water bodies

Are Amphipod invaders a threat to the regional biodiversity? Conservation prospects for the Loire River

The impact of invasions on local biodiversity is well established, but their impact on regional biodiversity has so far been only sketchily documented. To address this question, we studied the impact at various observation scales (ranging from the microhabitat to the whole catchment) of successive arrivals of non-native amphipods on the amphipod assemblage of the Loire River basin in France. Amphipod assemblages were studied at 225 sites covering the whole Loire catchment. Non-native species were dominant at all sites in the main channel of the Loire River, but native species were still present at most of the sites. We found that the invaders have failed to colonize most of tributaries of the Loire River. At the regional scale, we found that since the invaders first arrived 25 years ago, the global amphipod diversity has increased by 33% (from 8 to 12 species) due to the arrival of non-native species. We discuss the possibility that the lack of any loss of biodiversity may be directly linked to the presence of refuges at the microhabitat scale in the Loire channel and in the tributaries, which invasive species have been unable to colonize. The restoration of river quality could increase the number of refuges for native species, thus reducing the impact of invader

Functional diversity and community assembly of river invertebrates show globally consistent responses to decreasing glacier cover

Global change threatens invertebrate biodiversity and its central role in numerous ecosystem functions and services. Functional trait analyses have been advocated to uncover global mechanisms behind biodiversity responses to environmental change, but the application of this approach for invertebrates is underdeveloped relative to other organism groups. From an evaluation of 363 records comprising >1.23 million invertebrates collected from rivers across nine biogeographic regions on three continents, consistent responses of community trait composition and diversity to replicated gradients of reduced glacier cover are demonstrated. After accounting for a systematic regional effect of latitude, the processes shaping river invertebrate functional diversity are globally consistent. Analyses nested within individual regions identified an increase in functional diversity as glacier cover decreases. Community assembly models demonstrated that dispersal limitation was the dominant process underlying these patterns, although environmental filtering was also evident in highly glacierized basins. These findings indicate that predictable mechanisms govern river invertebrate community responses to decreasing glacier cover globally.This work was funded by the following organisations: The UK Natural Environment Research Council grants and studentships GR9/2913, NE/E003729/1, NE/E004539/1, NE/E004148/1, 20 NE/G523963/1, NER/S/A/2003/11192, and NE/L002574/1; the European Union Environment and Climate Programme Arctic and Alpine Stream Ecosystem Research (AASER) project (ENV-CT95-0164); EU-FP7 Assessing Climate impacts on the Quality and quantity of WAter (ACQWA) project (212250); Icelandic Research Council (954890095, 954890096); University of Iceland Research Fund (GMG96, GMG97, GMG98), Wyoming Center for Environmental Hydrology and Geophysics-National Science Foundation (1208909); USA-Wyoming NASA Space Grant Faculty Research Initiation (#NNX10A095H); USA-NSF Wyoming Epscor; Nationalpark Hohe Tauern, Austria; the Royal Society (International Outgoing Grant 2006/R4); the Leverhulme Trust; the Universities of Leeds, Birmingham, Iceland and Innsbruck; European Centre for Arctic Environmental Research (ARCFAC): a Research Infrastructures Action of the European Community FP6 (026129-2008- 72); the Stelvio National Park (2000-2001); the Autonomous Province of Trento (HIGHEST project, 2001-2004, del. PAT n. 1060/2001; VETTA project, 2003-2006, del. PAT n. 3402/2002); MUSE-Museo delle Scienze. We are grateful to Russell Taylor and Mike Winterbourn at the University of Canterbury, NZ, who helped to collect NZ invertebrate data and assisted with identification, and to Hakon Adalsteinsson who contributed to data collection in Iceland. Many other people, too numerous to mention, assisted with fieldwork at all of the study locations. The European Science Foundation sponsored an exploratory ┘ﾗヴﾆゲｴﾗヮ WﾐデｷデﾉWS さGﾉ;IｷWヴ-fed rivers, hydroecology and climate change: current knowledge and future network of monitoring sites (GLAC-HYDROECO-NETぶざ デｴ;デ ┘;ゲ ｴWﾉS ｷﾐ Birmingham, UK in September of 2013 where some of the ideas in this paper were first discussedPeer Reviewe

Measuring, in solution, multiple-fluorophore labeling by combining Fluorescence Correlation Spectroscopy and photobleaching

Determining the number of fluorescent entities that are coupled to a given molecule (DNA, protein, etc.) is a key point of numerous biological studies, especially those based on a single molecule approach. Reliable methods are important, in this context, not only to characterize the labeling process, but also to quantify interactions, for instance within molecular complexes. We combined Fluorescence Correlation Spectroscopy (FCS) and photobleaching experiments to measure the effective number of molecules and the molecular brightness as a function of the total fluorescence count rate on solutions of cDNA (containing a few percent of C bases labeled with Alexa Fluor 647). Here, photobleaching is used as a control parameter to vary the experimental outputs (brightness and number of molecules). Assuming a Poissonian distribution of the number of fluorescent labels per cDNA, the FCS-photobleaching data could be easily fit to yield the mean number of fluorescent labels per cDNA strand (@ 2). This number could not be determined solely on the basis of the cDNA brightness, because of both the statistical distribution of the number of fluorescent labels and their unknown brightness when incorporated in cDNA. The statistical distribution of the number of fluorophores labeling cDNA was confirmed by analyzing the photon count distribution (with the cumulant method), which showed clearly that the brightness of cDNA strands varies from one molecule to the other.Comment: 38 pages (avec les figures

Two indigenous European crayfish under threat – how can we retain them in aquatic ecosystems for the future?

Indigenous crayfish species (ICS) are under threat in Europe; due to competition from invasive non-indigenous crayfish species (NICS) from crayfish plague, which is carried by introduced American crayfish, and habitat degradation. We focus on the white-clawed crayfish Austropotamobius pallipes and stone crayfish A. torrentium. Surveys in many countries have shown the accelerating rate of loss since the late 20th century; concurrent with rapid spread of NICS by human-assisted introductions and natural expansion. Remaining populations of ICS are becoming fragmented. As NICS become ever more extensive, it will become progressively harder to retain populations of European ICS. Legal protection alone is not sufficient against the major threats from NICS and crayfish plague. We recommend catchment-scale risk assessments, to identify threats and to guide action plans: (1) populations of ICS where loss is inevitable, (2) those at some risk that can be made more secure by various measures and (3) existing or new isolated populations that can be kept secure, “ark sites”. Resources can be targeted to achieve specific conservation goals. Ark sites are likely to offer the best chance for survival of both Austropotamobius species, where there are invading NICS. We discuss constraints and opportunities and the need for public involvement