Combining taxon-by-trait and taxon-by-site matrices for analysing trait patterns of macroinvertebrate communities: a rejoinder to Monaghan & Soares (2014)

In a recent paper, Heino, Schmera & Erős (2013) provided an overview of trait 58 patterns of stream communities from a macroecological perspective. In this paper , 59 reference was made to Gayraud et al . (2003) , who showed that abundance - weighted 60 traits were less powe rful than presence - absence weighted traits in discriminating 61 communities under different degrees of human impacts , and to Statzner & Beche 62 (2010) , who therefore advocated the use of the second type of weighting for practical 63 biomonitoring due to logis tic constrains ( e.g. sorting of qualitative samples makes 64 3 assessment program me s more cost effective) . H eino et al . (2013) pointed out that 65 t hese findings contradict the results of taxon - based analyses which suggest that , if 66 taxa are weighted by their abund ance , then communities are better separated in 67 relation to environmental variation than when taxa are weighted only by their 68 presence . Based on an overview of the literature, Heino et al . (2013) concluded that 69 results of presence - and abundance - based analy ses should be evaluated carefully 70 when examining traits of organisms, because differences among studies can reflect 71 both methodological (i.e. handling of data) and real ecological differences (see p. 72 1549 in H eino et al ., 2013 ) . More recently, Monaghan & S oares (2014 ) stated that (1) 73 H eino et al . (2013) identified the weak explanatory power of abundance data as a 74 major limitation of macroinvertebrat e trait analysis and that (2) the log - transformation 75 of abundance data may cause anomalies in trait - based anal yses. W e disagree with 76 both conclusions , because (1) H eino et al . (2013) did not actually state this (see 77 above) and because (2), in our view, log - transformation of abundance data in trait - 78 based analyses can also be meaningful . To reveal the causes of thes e differ ing views , 79 we go through the examples provided by M onaghan & Soares (2014) and examine 80 how traits can be weighted by the presence, abundance and log - transformed 81 abundance of the taxa . To do this, firs t we define the terminology used here , comment 82 o n the approach of M onaghan & Soares (2014) and show how this procedure should 83 be performed

Persistence in the longitudinal distribution of lotic insects in a changing climate: a tale of two rivers

The longitudinal distribution of many taxa in rivers is influenced by temperature. Here we took advantage of two older datasets on net-spinning caddisflies (Hydropsychidae) from contrasting European rivers to assess changes in species occurrence and relative abundance along the river by resampling the same sites, postulating that an increase in river temperature over the intervening period should have resulted in cool-adapted species retreating into the headwaters and warm adapted species expanding upstream. Distributional changes in the Welsh Usk were slight between 1968/69 and 2010, one rare species appearing at a single headwater site and one warm-adapted species disappearing from the main river. Distributional changes in the French Loire, between 1989–93 and 2005, were similarly modest, with no consistent movement of species up- or downstream. We estimate that the decadal rate of increase in the mean summer daily maximum in the Usk was only 0.1 °C at one ‘summer cool’ headwater site, while a neighbouring ‘summer warm’ tributary increased by 0.16 °C per decade, and the main river by 0.22 °C. The Loire is warmer than the Usk and the mean decadal rates of increase, over the period 1989–2005, at three sites along the lower reaches were 0.39, 0.48 and 0.77 °C. Increases in stream and river temperature, therefore, were spatially variable and were not associated with consistent upstream movement of species in either of these (very different) rivers. We conclude that either the temperature increases have hitherto been insufficient to affect species distribution or, more speculatively, that it may not be possible for river organisms (that do not respond only to temperature) to move upstream because of a developing spatial mismatch between key habitat characteristics, some of them changing with the climate but others not

Field experiment on the relationship between drift and benthic densities of aquatic insects in tropical streams (Ivory Coast) : 3 : Tricoptera

1) En se fondant sur des expériences #in situ en gouttières, la dérive des Tricoptères est reliée à leur densité benthique et à différents facteurs abiotiques des rivières de Côte d'Ivoire (Afrique de l'Ouest). Les représentants des familles #Hydropsychidae, Philopotamidae, Hydroptilidae et #Leptoceridae$ sont considérés en détail. 2) La dérive est maximale durant la nuit aussi bien chez les jeunes larves que les âgées. 3) La dérive d'un groupe larvaire (certains stades, certaines espèces ou certains taxons de rang supérieur) est plus souvent reliée à la densité des autres groupes larvaires qu'à sa propre densité benthique. 4) L'autorégulation des densités benthiques les plus grandes par émigration au moyen de la dérive n'est pas prouvée. 5) Il n'y a pas de relation entre la dérive et les facteurs abiotiques. 6) Les taux de dérive diffèrent aussi bien entre les taxons qu'entre les stades larvaires (classes de taille) à l'intérieur d'un taxon. Les larves nouvellement écloses ont un taux de dérive très élevé tandis que les derniers stades larvaires dérivent le moins

Habitat filtering determines spatial variation of macroinvertebrate community traits in northern headwater streams

Although our knowledge of the spatial distribution of stream organisms has been increasing rapidly in the last decades, there is still little consensus about trait-based variability of macroinvertebrate communities within and between catchments in near-pristine systems. Our aim was to examine the taxonomic and trait based stability vs. variability of stream macroinvertebrates in three high-latitude catchments in Finland. The collected taxa were assigned to unique trait combinations (UTCs) using biological traits. We found that only a single or a highly limited number of taxa formed a single UTC, suggesting a low degree of redundancy. Our analyses revealed significant differences in the environmental conditions of the streams among the three catchments. Linear models, rarefaction curves and beta-diversity measures showed that the catchments differed in both alpha and beta diversity. Taxon- and trait-based multivariate analyses also indicated that the three catchments were significantly different in terms of macroinvertebrate communities. All these findings suggest that habitat filtering, i.e., environmental differences among catchments, determines the variability of macroinvertebrate communities, thereby contributing to the significant biological differences among the catchments. The main implications of our study is that the sensitivity of trait-based analyses to natural environmental variation should be carefully incorporated in the assessment of environmental degradation, and that further studies are needed for a deeper understanding of trait-based community patterns across near-pristine streams

Inflated Impact Factors? The True Impact of Evolutionary Papers in Non-Evolutionary Journals

Amongst the numerous problems associated with the use of impact factors as a measure of quality are the systematic differences in impact factors that exist among scientific fields. While in theory this can be circumvented by limiting comparisons to journals within the same field, for a diverse and multidisciplinary field like evolutionary biology, in which the majority of papers are published in journals that publish both evolutionary and non-evolutionary papers, this is impossible. However, a journal's overall impact factor may well be a poor predictor for the impact of its evolutionary papers. The extremely high impact factors of some multidisciplinary journals, for example, are by many believed to be driven mostly by publications from other fields. Despite plenty of speculation, however, we know as yet very little about the true impact of evolutionary papers in journals not specifically classified as evolutionary. Here I present, for a wide range of journals, an analysis of the number of evolutionary papers they publish and their average impact. I show that there are large differences in impact among evolutionary and non-evolutionary papers within journals; while the impact of evolutionary papers published in multidisciplinary journals is substantially overestimated by their overall impact factor, the impact of evolutionary papers in many of the more specialized, non-evolutionary journals is significantly underestimated. This suggests that, for evolutionary biologists, publishing in high-impact multidisciplinary journals should not receive as much weight as it does now, while evolutionary papers in more narrowly defined journals are currently undervalued. Importantly, however, their ranking remains largely unaffected. While journal impact factors may thus indeed provide a meaningful qualitative measure of impact, a fair quantitative comparison requires a more sophisticated journal classification system, together with multiple field-specific impact statistics per journal

From microhabitat ecohydraulics to an improved management of river catchments: bridging the gap between scales

[EN] Ecohydraulic studies in rivers range from local-scale studies, which target a better understanding of the mechanisms underlying biological responses to microhabitat hydraulics, to large-scale studies, which address the influence of hydro-morphological management on catchment biodiversity. A major challenge in the field is to bridge the gap between local- and large-scale studies, in order to base the large-scale physical management of rivers on general and transferable ecohydraulic processes. This Special Issue includes ten articles that illustrate progresses and difficulties to bridge this gap. It gathers microhabitat-scale studies focused on the identification of major ecohydraulic mechanisms, reach-scale studies that typically target generality and transferability across reaches, and examples of catchment-scale management based on general ecohydrological knowledge. The Special Issue illustrates how ecohydraulics have evolved to better integrate dynamic physical processes, ecological concepts and the consideration of ecosystem services. Although this remains challenging in practice, the Special Issue shows the need to integrate dynamic hydraulic descriptors of the environment for improving the cost-effectiveness of large-scale rivermanagement and restoration. These articles were presented at the 10th International Symposium on Ecohydraulics in Trondheim, Norway (2014), where the first symposium on ecohydraulics was organised 20 years before. The 10th issue of the symposium celebrated 20 years of ecohydraulic research and had about 300 delegates, giving 194 talks and presenting 86 posters.Harby, A.; Martinez-Capel, F.; Lamouroux, N. (2017). From microhabitat ecohydraulics to an improved management of river catchments: bridging the gap between scales. River Research and Applications. 33:189-191. doi:10.1002/rra.3114S18919133Anderson, D., Moggridge, H., Shucksmith, J. D., & Warren, P. H. (2015). Quantifying the Impact of Water Abstraction for Low Head ‘Run of the River’ Hydropower on Localized River Channel Hydraulics and Benthic Macroinvertebrates. River Research and Applications, 33(2), 202-213. doi:10.1002/rra.2992Doyle, M. W., Stanley, E. H., Strayer, D. L., Jacobson, R. B., & Schmidt, J. C. (2005). Effective discharge analysis of ecological processes in streams. Water Resources Research, 41(11). doi:10.1029/2005wr004222Egger, G., Politti, E., Lautsch, E., Benjankar, R. M., & Rood, S. B. (2016). Time and Intensity Weighted Indices of Fluvial Processes: a Case Study from the Kootenai River, USA. River Research and Applications, 33(2), 224-232. doi:10.1002/rra.2997Hailegeorgis, T. T., & Alfredsen, K. (2016). Regional Statistical and Precipitation-Runoff Modelling for Ecological Applications: Prediction of Hourly Streamflow in Regulated Rivers and Ungauged Basins. River Research and Applications, 33(2), 233-248. doi:10.1002/rra.3006Lamouroux, N., Pella, H., Snelder, T. H., Sauquet, E., Lejot, J., & Shankar, U. (2013). Uncertainty Models for Estimates of Physical Characteristics of River Segments Over Large Areas. JAWRA Journal of the American Water Resources Association, 50(1), 1-13. doi:10.1111/jawr.12101Harby, A., Martinez- Capel, F., & Lamouroux, N. (2017). From Microhabitat Ecohydraulics to an Improved Management of River Catchments: Bridging the gap Between Scales. River Research and Applications, 33(2), 189-191. doi:10.1002/rra.3114Martínez-Capel, F., García-López, L., & Beyer, M. (2016). Integrating Hydrological Modelling and Ecosystem Functioning for Environmental Flows in Climate Change Scenarios in the Zambezi River (Zambezi Region, Namibia). River Research and Applications, 33(2), 258-275. doi:10.1002/rra.3058Martínez-Fernández, V., González del Tánago, M., Maroto, J., & García de Jalón, D. (2016). Fluvial Corridor Changes Over Time in Regulated and Non-Regulated Rivers (Upper Esla River, NW Spain). River Research and Applications, 33(2), 214-223. doi:10.1002/rra.3032Mathews, R., & Richter, B. D. (2007). Application of the Indicators of Hydrologic Alteration Software in Environmental Flow Setting1. JAWRA Journal of the American Water Resources Association, 43(6), 1400-1413. doi:10.1111/j.1752-1688.2007.00099.xNoack, M., Ortlepp, J., & Wieprecht, S. (2016). An Approach to Simulate Interstitial Habitat Conditions During the Incubation Phase of Gravel-Spawning Fish. River Research and Applications, 33(2), 192-201. doi:10.1002/rra.3012Nzau Matondo, B., Benitez, J. P., Dierckx, A., Philippart, J. C., & Ovidio, M. (2016). Assessment of the Entering Stock, Migration Dynamics and Fish Pass Fidelity of European Eel in the Belgian Meuse River. River Research and Applications, 33(2), 292-301. doi:10.1002/rra.3034Parasiewicz P Castelli E Rogers J Vezza P Kapusta A 2017 Implementation of the natural flow paradigm to protect dwarf wedgemussel ( Alasmidonta heterodon ) in the upper Delaware River River Research and Applications 33 2 276 290 10.1002/rra.3112Rice, S. P., Little, S., Wood, P. J., Moir, H. J., & Vericat, D. (2010). The relative contributions of ecology and hydraulics to ecohydraulics. River Research and Applications, 26(4), 363-366. doi:10.1002/rra.1369Roy, M. L., Roy, A. G., & Legendre, P. (2010). The relations between ‘standard’ fluvial habitat variables and turbulent flow at multiple scales in morphological units of a gravel-bed river. River Research and Applications, 26(4), 439-455. doi:10.1002/rra.1281Seliger, C., Scheikl, S., Schmutz, S., Schinegger, R., Fleck, S., Neubarth, J., … Muhar, S. (2015). Hy:Con: A Strategic Tool For Balancing Hydropower Development And Conservation Needs. River Research and Applications, 32(7), 1438-1449. doi:10.1002/rra.2985Statzner, B., Gore, J. A., & Resh, V. H. (1988). Hydraulic Stream Ecology: Observed Patterns and Potential Applications. Journal of the North American Benthological Society, 7(4), 307-360. doi:10.2307/1467296Vowles, A. S., Eakins, L. R., Piper, A. T., Kerr, J. R., & Kemp, P. (2013). Developing Realistic Fish Passage Criteria: An Ecohydraulics Approach. Ecohydraulics, 143-156. doi:10.1002/9781118526576.ch

Invasive crayfish as drivers of fine sediment dynamics in rivers: Field and laboratory evidence

Despite increasing recognition of the potential of aquatic biota to act as 'geomorphic agents', key knowledge gaps exist in relation to biotic drivers of fine sediment dynamics at microscales and particularly the role of invasive species. This study explores the impacts of invasive signal crayfish on suspended sediment dynamics at the patch scale through laboratory and field study. Three hypotheses are presented and tested: (1) that signal crayfish generate pulses of fine sediment mobilisation through burrowing and movement that are detectable in the flow field; (2) that such pulses may be more frequent during nocturnal periods when signal crayfish are known to be most active; and (3) that cumulatively the pulses would be sufficient to drive an overall increase in turbidity. Laboratory mesocosm experiments were used to explore crayfish impacts on suspended sediment concentrations for two treatments: clay banks and clay bed substrate. For the field study, high frequency near-bed and mid-flow turbidity time series from a lowland river with known high densities of signal crayfish were examined. Laboratory data demonstrate the direct influence of signal crayfish on mobilisation of pulses of fine sediment through burrowing into banks and fine bed material, with evidence of enhanced activity levels around the mid-point of the nocturnal period. Similar patterns of pulsed fine sediment mobilisation identified under field conditions follow a clear nocturnal trend and appear capable of driving an increase in ambient turbidity levels. The findings indicate that signal crayfish have the potential to influence suspended sediment yields, with implications for morphological change, physical habitat quality and the transfer of nutrients and contaminants. This is particularly important given the spread of signal crayfish across Europe and their presence in extremely high densities in many catchments. Further process-based studies are required to develop a full understanding of impacts across a range of river styles. © 2013 John Wiley & Sons, Ltd.The research was supported by a British Society for Geomorphology Research Grant (‘Field evidence for signal crayfish impacts on fine sediment dynamics in a lowland river’). Tom Moorhouse was funded by the Esmée Fairbairn Foundation