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Biodiversity loss in freshwater ecosystems: causes and consequences Oulanka Research Station, FINLAND September 8th – 11th, 2014 2 Acknowledgements NORBS 2014 has been based on voluntary work by the organizing and scientific committees. Their contribution and quality of work have been tremendous and of vital importance. Special thanks go to plenary speakers for their contribution; Brendan McKie (Swedish Agricultural University, Sweden), Sonja Jähnig (Leibniz Institute for Freshwater Ecology and Inland Fisheries, Germany), Charles Hawkins (Utah State University, USA), Ian Donohue (University of Dublin, Ireland), and N. LeRoy Poff (Colorado State University, USA). Without them this would not have been possible. We acknowledge our sponsors for financial support: Maj and Tor Nessling Foundation, Federation of Finnish Learned Societies, and Thule institute, University of Oulu. Thank you! The organizing committee of the NORBS 2014 consisted of following people: Professor Timo Muotka, University of Oulu Director Riku Paavola, Oulanka Research Station Postdoc Jussi Jyväsjärvi, University of Oulu Postdoc Pauliina Louhi, University of Oulu Phd student Kaisa-Leena Huttunen, University of Oulu The scientific committee of the NORBS 2014: All organizers listed above and Senior research scientist Jukka Aroviita, Finnish Environment Institute Senior research fellow Heikki Mykrä, Thule institute NORBS 2014, Oulanka Research Station, Finland 3 DETAILED SCHEDULE Monday 8 September 20:00 Arrival at Oulanka Research Station Get together Tuesday 9 September 08:00-09:00 Breakfast 9:15-10:00 Opening words and introduction of the Oulanka Research Station (Timo Muotka, Riku Paavola) Chair: Jan Herrman 10:00-10:45 Plenary talk Brendan McKie, Swedish Agricultural University, Uppsala, Sweden: Björn Malmqvist’s laboratory: Insights into the relationship between detritivore diversity and litter decomposition from boreal streams A short break 10:50-11:10 Jonas Persson: Can the CNP stoichiometry of Nordic EPT invertebrates help us understand their organic pollution tolerance? 11:10-11:30 Mikko Tolkkinen: Anthropogenic disturbance decreases functional stability in streams 11:30-11:50 Kaisa Mustonen: Experimental manipulation of flow and sedimentation: effects on stream communities and ecosystem processes 12:00-13:00 Lunch Chair: 13:10-13:55 Plenary talk Sonja Jähnig, Leibniz Institute for Freshwater ecology and Inland Fisheries, Berlin, Germany: Assessing effects of global change on stream benthic invertebrates A short break 14:00-14:20 Romain Sarremejane: Modeling of future stream macroinvertebrate communities under climate change NORBS 2014, Oulanka Research Station, Finland 4 14:20-14:40 Mari Annala: Community structure and concordance of three taxonomic groups in multi-stressed streams 14:40-15:00 Mira Grönroos: Assessing the strength of distance decay of community similarity at hierarchical spatial scales 15:00-15:30 Coffee break Chair: Riku Paavola 15:30-16:15 Plenary talk Charles Hawkins, Utah State University, Logan, USA: Predictability and vulnerability of freshwater biodiversity to landscape alteration and climate change A short break 16:20-16:40 Mika Nieminen: Assessing the impacts of forestry and peat mining on boreal headwater streams using the chironomid pupal exuviae technique 16:40-17:00 Riccardo Fornaroli: Predicting the constraint effect of environmental characteristics on macroinvertebrate density and diversity using quantile regression mixed model 17:00-17:20 Henn Timm: Identification guide to freshwater macroinvertebrates of Estonia 17:30 Dinner 18:00 Sauna & social Wednesday 10 September 8:00-9:00 Breakfast Chair: Pauliina Louhi 09:00-9:45 Plenary talk Ian Donohue, University of Dublin, Ireland: Biodiversity loss and the stability of ecosystems A short break 9:50-10:10 Jarno Turunen: Restoration of sediment-stressed forest streams has little effects on benthic biodiversity and ecosystem functions 10:10-10:30 Peter Wiberg-Larsen: Restoration of River Skjerne – did biodiversity of macroinvertebrates and macrophytes improve? 10:30-10:50 Jan Herrman: Tench population size regulating invertebrate numbers: a conservation management tool? 11:00-12:00 Lunch 12:30-16:30 Field trip NORBS 2014, Oulanka Research Station, Finland 5 17:30 Departure for Oivanki (Conference dinner) 18:30-19:00 Introduction to River Oulankajoki and Oulanka Nature Park (slide show by Dr. Pirkko Siikamäki, Finnish Forest and Park Services) 19:00-22:00 Conference dinner Thursday 11 September 08:00-09:00 Breakfast Chair: Leonard Sandin 09:00-09:45 N. LeRoy Poff, Colorado State University, Ft. Collins, USA: Using traits-based approaches to project biodiversity loss and functional shifts in stream benthic communities under rapid climate change A short break 09:50-10:10 Annika Vilmi: Unravelling the drivers of freshwater diatom biodiversity in the context of large-lake assessment 10:10-10:30 Kimmo Tolonen: Do different facets of littoral macroinvertebrate diversity respond similarly to ecological gradients in a large boreal lake? 10:30-10:50 Kaisa-Leena Huttunen: Habitat complexity enhances the stability of stream macroinvertebrate communities 10:50-11:15 General assembly: Is there a future for Norbs? 11:15-12:00 Lunch, Adjourn NORBS 2014, Oulanka Research Station, Finland 6 PLENARY BJÖRN MALMQVIST’S LABORATORY: INSIGHTS INTO THE RELATIONSHIP BETWEEN DETRITIVORE DIVERSITY AND LITTER DECOMPOSITION FROM BOREAL STREAMS Brendan G. McKie Department of Aquatic Sciences & Assessment, Swedish University of Agricultural Sciences, P.O. Box 7050, SE-75007 Uppsala, Sweden [email protected] http://www.slu.se/vatten-miljo/brendan-mckie Björn Malmqvist was one of the Nordic region’s leading stream and river ecologists, who combined a love of traditional, species-focused natural history with strongly question driven research, which drew on his broad knowledge of the wider ecological literature. This is demonstrated above all by the insight shown in his foray during the late 1990’s into the field of biodiversity-ecosystem functioning (B-EF) research. B-EF research investigates how ecosystemlevel processes, such as primary production or detrital decomposition, vary with biodiversity, most often expressed as species richness. In the late 1990’s, B-EF research focused largely on the process of plant productivity in terrestrial grasslands. While decomposition was measured as an additional parameter in some terrestrial studies, the early experiments and field studies conducted by Björn and his colleagues demonstrated the full potential of aquatic detrital food webs as model systems for B-EF research. Indeed, as a result of Björn’s pioneering research, our current understanding of how detritivore diversity affects leaf decomposition is based very largely on studies of boreal stream food-webs. Biodiversity is declining catastrophically in most ecosystems worldwide, and streams and rivers are no exception, with multiple human disturbances driving losses of species at local and regional scales. Most of the early stream B-EF research was conducted in laboratory microcosms, and these results indicate that increasing the species richness of detritivores often has positive effects on leaf decomposition and related ecosystem processes, though several examples of neutral and negative relationships also have been observed. However, the relevance of much of the laboratory-based research for predicting the likely effects of biodiversity loss in nature remains unclear, given the high degree of spatio-temporal dynamism in both environmental conditions and community composition and diversity that characterises stream environments. Indeed, after a decade of laboratory-based research, we remain unable to address some basic questions of key management relevance. For example, the importance of biodiversity for functioning in streams relative to other biotic and abiotic drivers remains unclear, as does the extent to which biodiversity can help buffer human impacts on functioning, and it is not possible to predict when and where biodiversity will be important for functioning in situ. To address these shortcomings, stream B-EF research has been shifting towards more field-based research, with a greater emphasis on the diversity of functional traits rather than species. Findings from these field studies provide strong evidence that biodiversity can be as important a driver of ecosystem functioning as other important abiotic and biotic drivers in situ, but not universally. Development of a framework for predicting exactly when and where species loss will have its greatest impact remains challenging. NORBS 2014, Oulanka Research Station, Finland 7 PLENARY ASSESSING EFFECTS OF GLOBAL CHANGE ON STREAM BENTHIC INVERTEBRATES Sonja Jähnig Leibniz Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany [email protected] Stream ecosystems are impacted in many ways, both directly and indirectly, e.g. by climate change and through interactions with other stressors such as land-use change, structural degradation or pollution by nutrients. Significant, widespread consequences have been observed and are further expected for the freshwater fauna. I will present different approaches to assess the vulnerability of stream biota to global change like species distribution models (SDMs), integrated modelling, or threshold analyses. SDMs inform about large scale potential effects from climate change, as shown for Europe and North America. Learning from the current range distributions of species and which environmental variables shape them we simulated how these ranges may shift through time under climate warming and land use change scenarios. However, these large-scale SDMs do not consider riverine characteristics sufficiently. To integrate stream specific data into SDMs is a challenging task that requires the integration of detailed datasets or hydrologic and hydraulic models. Yet, this promises further insights into combined effects of climate change, resulting possible flow changes, land use alterations and related water quality issues. Our research shows that drivers and pressures acting at large spatial scales influence and even limit macroinvertebrate assemblages. Both aspects have implications for applied issues, like local management measures such as restoration, or monitoring, e.g. on the detection of climate sensitive zones. NORBS 2014, Oulanka Research Station, Finland 8 PLENARY PREDICTABILITY AND VULNERABILITY OF FRESHWATER BIODIVERSITY TO LANDSCAPE ALTERATION AND CLIMATE CHANGE Charles Hawkins Utah State University, Department of Watershed Sciences and Ecology Center, 5210 Old Main Hill, Logan, Utah 84322-5210, USA [email protected] Landscape and waterway alteration has severely altered the local and regional biodiversity of freshwater ecosystems on most of the planet. Climate change is expected to further affect freshwater biodiversity by directly affecting thermal and hydrologic regimes including those of systems that have largely escaped the effects of landscape alteration. In this talk I will summarize work my lab has conducted in collaboration with others to better understand the predictability and vulnerability of freshwater ecosystems to human-caused stress. Much of our work has involved use of large data sets produced by the USEPA, other agencies, and my lab to develop and link climate, water temperature, hydrologic, and biodiversity models. From this work we have discovered that local assemblage composition can be well predicted from 4-5 hydrologic, thermal, and geomorphic variables; predictability of composition decreases and beta diversity increases with decreasing drainage density, increasing aridity, and increasing nutrient concentration; climate change may have as large of an effect on local biodiversity as that of landscape alteration; and vulnerability of individual water bodies to climate change will be variable and contingent on local factors that mitigate thermal and hydrologic response to climate change. These model results represent hypotheses in need of experimental testing. NORBS 2014, Oulanka Research Station, Finland 9 PLENARY BIODIVERSITY LOSS AND THE STABILITY OF ECOSYSTEMS Ian Donohue Department of Zoology, School of Natural Sciences, Ireland and Trinity Centre for Biodiversity Research, Trinity College Dublin, Ireland [email protected] Ecological networks are tightly interconnected, such that the extinction of a single species can initiate a sequence of events triggering additional species losses. However, strong perturbations such as species loss can destabilize ecosystems in a variety of frequently unanticipated and unpredictable ways. I will discuss how explicit appreciation of the multifaceted nature of ecological stability is essential in order to understand the true potential for perturbations to destabilize ecosystems. I will also show how microevolution may be as important as species extinctions in shaping the response of communities to environmental change. NORBS 2014, Oulanka Research Station, Finland 10 PLENARY USING TRAITS-BASED APPROACHES TO PROJECT BIODIVERSITY LOSS AND FUNCTIONAL SHIFTS IN STREAM BENTHIC COMMUNITIES UNDER RAPID CLIMATE CHANGE N. LeRoy Poff Colorado State University, Ft. Collins, USA [email protected] Predicting responses of aquatic species and communities to climate change is a key scientific challenge. By linking species attributes to dominant environmental drivers that vary across the landscape, a traits-based approach can be used to help explain current variation in species abundance and local community structure. Similarly, by linking species occurrence or abundance to variable thermal and hydrologic conditions across large spatial extents, it is possible to evaluate species assemblage responses to projected changes in temperature and precipitation expected under rapid climate change. Species’ vulnerability to deviations in temperature and precipitation depends on the sensitivity of individual species to changing conditions – this varies among species and across species’ ranges. In addition, vulnerability reflects the projected exposure of species populations to local climate-induced changes in temperature and flow conditions – this also varies geographically. In this presentation, the rationale for using traits-based approaches to predict species and community responses to climate change will be presented, along with a specific analysis that evaluates sensitivity of 88 widely distributed benthic insect species across broad spatial gradients of temperature and streamflow conditions in 251 “reference” stream reaches across 12 states and 8 ecoregions in the western United States. Using downscaled climate change projections, site-specific vulnerability of species to projected shifts in temperature and flow is quantified to assess risk of species deletions and associated reductions in biodiversity and changes in community function from local to ecoregional scales. NORBS 2014, Oulanka Research Station, Finland 11 CAN THE CNP STOICHIOMETRY OF NORDIC EPT INVERTEBRATES HELP US UNDERSTAND THEIR ORGANIC POLLUTION TOLERANCE? Persson, J.(1) (1) The Norwegian Institute for Water Research (NIVA), Gaustadalléen 21 NO-0349 Oslo Norway [email protected] Macroinvertebrate pollution scores that rely on that macroinvertebrate taxa differ in their tolerance to organic pollution are routinely used to monitor running waters. However, the mechanisms behind these taxonomic differences in tolerance are relatively unexplored. I will test if the tolerance levels of macroinvertebrates are related to their stoichiometric composition (carbon (C), nitrogen (N), phosphorus (P). The N and P content of aquatic autotrophs are relatively flexible; in contrast, they are constrained within narrower ranges in heterotrophs. This observation leads to the question whether macroinvertebrates with higher nutrient content, and presumably high nutrient requirements, are more likely to be found in more nutrient-rich (i.e., polluted) sites, containing food with higher nutrient content. The present study will focus on the stoichiometric variation within the Nordic EPT taxa (May-, Stone- and Caddis-flies), which are very important in environmental monitoring. Their CNP stoichiometry will be related to BMWP tolerance scores, taxonomy, and functional groups. NORBS 2014, Oulanka Research Station, Finland 12 ANTHROPOGENIC DISTURBANCE DECREASES FUNCTIONAL STABILITY IN STREAMS Tolkkinen M. (1), Mykrä H.(2), Markkola AM. (3), Muotka T. (3) (1) Finnish Environment Institute, Oulu Office, P.O.Box 413, FI-90014, University of Oulu, Finland, [email protected] (2) Thule Institute, P.O. Box 7300, FIN-90014, University of Oulu, Finland (3) Department of Biology, P.O. Box 3000, 90014 University of Oulu, Finland Compelling evidence shows that species diversity may enhance temporal stability of ecosystem function, suggesting that disturbance-induced loss of biodiversity could destabilize ecosystem function. In temporally varying environments, however, functional stability is often regulated by the same environmental factors that also shape diversity, and these other factors could be more important drivers of stability than diversity per se. Using field experiments conducted during three consecutive years we examined the effects of anthropogenic disturbances in creating temporal variability of fungal communities and leaf litter decomposition in boreal streams. Temporal variability of decomposition rates was higher in disturbed sites than in near pristine reference sites. Despite the higher degree of variation in decomposition rates in disturbed sites, there were no differences in mean decomposition rates among the stream groups. Among-year variability of decomposition rates was positively related to among-year variability in water chemistry and fungal OTU evenness. Fungal communities in disturbed sites were less diverse and more dominated by a few key taxa than communities in reference sites, yet they were as stable as those at reference sites. Our results outline the need to examine variability of ecosystem processes, because responses to anthropogenic stress may be overlooked by focusing solely on mean rates. NORBS 2014, Oulanka Research Station, Finland 13 EXPERIMENTAL MANIPULATION OF FLOW AND SEDIMENTATION: EFFECTS ON STREAM COMMUNITIES AND ECOSYSTEM PROCESSES Mustonen K.(1), Mykrä H.(2), Louhi P.(3), Tolkkinen M.(4), Alioravainen N.(5), Lehtinen S.(6), Markkola A.(7), Marttila H.(8), Tammela S.(9), Klöve B.(10), Huusko A.(11), Muotka T.(12) (1) Thule Institute, P.O. Box 7300, FI-90014 University of Oulu, Finland, [email protected] Thule Institute, P.O. Box 7300, FI-90014 University of Oulu, Finland, [email protected] (3) Department of Biology, P.O. Box 3000, FI-90014 University of Oulu, Finland, [email protected] (4) Finnish Environment Institute, P.O. Box 413, FI-90014 University of Oulu, Finland, [email protected] (5) Department of Biology, P.O. Box 3000, FI-90014 University of Oulu, Finland, [email protected] (6) Department of Biology, P.O. Box 3000, FI-90014 University of Oulu, Finland, [email protected] (7) Department of Biology, P.O. Box 3000, FI-90014 University of Oulu, Finland, [email protected] (8) Water Resources and Environmental Engineering Research Group, P.O. Box 4300, FI-90014 University of Oulu, Finland, [email protected] (9) Water Resources and Environmental Engineering Research Group, P.O. Box 4300, FI-90014 University of Oulu, Finland, [email protected] (10) Water Resources and Environmental Engineering Research Group, P.O. Box 4300, FI-90014 University of Oulu, Finland, [email protected] (11) Finnish Game and Fisheries Research Institute, Manamansalontie 90, FI-88300 Paltamo, Finland, [email protected] (12) Department of Biology, P.O. Box 3000, FI-90014 University of Oulu, Finland, [email protected] (2) Stream ecosystems are affected by multiple abiotic stressors, and species responses to different stressors may differ from those predicted based on the individual effects of each stressor alone. Using 12 artificial streams we examined the individual and interactive effects of flow and fine sediments (sand grain size < 2mm) on benthic macroinvertebrates and ecosystem processes (leaf litter breakdown rate; algal biomass accrual). Sediment addition had a negative effect on benthic algal biomass and microbial leaf breakdown rates, whereas responses of macroinvertebrates were more variable. Algal biomass increased in high-flows, whereas in low-flows both microbial and macroinvertebrate-induced leaf breakdown rates were enhanced. This study reveals the complicated nature of the interaction between flow and sedimentation in lotic ecosystems, and how variably community and ecosystem-level factors respond to these stressors, highlighting the importance of the use of multiple measures of stream ecosystem health. NORBS 2014, Oulanka Research Station, Finland 14 MODELING OF FUTURE STREAM MACROINVERTEBRATE COMMUNITIES UNDER CLIMATE CHANGE Mustonen K.(1), Sarremejane R. (2), Mykrä H. (3, 4), Marttila H. (5), Muotka T.(6,4) (1) Thule institute, University of Oulu, Finland, [email protected] Thule institute, University of Oulu, Finland, [email protected] (3) Thule institute, University of Oulu, Finland, [email protected] (4) Finnish Environment Institute, Paavo Havaksen tie 3, 90570 Oulu. (5) Water Resources and Environmental Engineering Research Group, University of Oulu, Finland, [email protected] (6) Department of Biology, University of Oulu, Finland, [email protected] (2) At the northernmost latitudes, air temperature is predicted to increase steeply by the end of the century. Precipitation and snow-fall are also predicted to change with potentially significant effects on flow regimes. In boreal regions, water temperatures are unlikely to exceed the upper physiological limits of warm-water species, but cold-water species may be unable to escape the novel thermal regimes and their distributions may be strongly affected by global warming. Lotic organisms are also likely to confront novel flow regimes, in particular in headwater streams with low and variable discharges. We used site-specific modeled air temperatures and flow regime indices to predict the future macroinvertebrate community composition of 240 sites sampled across Finland. We developed a River Invertebrates Prediction and Classification System (RIVPACS)-type model to predict the present-day composition of macroinvertebrate communities and to evaluate potential future changes in composition of these communities. The final model was built using six environmental variables related to flow and temperature. Preliminary results revealed changes in observed to expected (O/E) ratios of macroinvertebrate taxa when predicted communities were compared to present day communities. More analyses will be conducted to identify the species and stream types most vulnerable to climate change. NORBS 2014, Oulanka Research Station, Finland 15 COMMUNITY STRUCTURE AND CONCORDANCE OF THREE TAXONOMIC GROUPS IN MULTI-STRESSED STREAMS Annala, M.(1), Mykrä, H.(2,3), Tolkkinen, M.(3), Kauppila, T.(4), Paasivirta, L.(5), Muotka, T.(1,3) (1) (2) (3) (4) (5) Department of Biology, P.O. Box 3000, FI-90014, University of Oulu, Finland Thule Institute, P. O. Box 7300, FI-90014, University of Oulu, Finland Finnish Environment Institute, Oulu Office, P.O. Box 413, FI-90014, University of Oulu, Finland Geological Survey of Finland, P.O. Box 1237, FI-70211, Kuopio, Finland Ruuhikoskenkatu 17 B 5, FI-24240, Salo, Finland Studies on the interactive effects of multiple stressors on biological communities have focused on individual or population-level responses in laboratory microcosms, while field-based studies on community-level responses are rare. We examined the influence of natural vs. human-induced stress and their interaction on the community composition of diatoms, bryophytes and macroinvertebrates. We further assessed the effects of underlying environmental gradients on community concordance among the biological groups and identified the most important environmental variables structuring these communities. We sampled 12 sites in each of the four stream categories: circumneutral reference, circumneutral impacted, naturally acidic and naturally acidic impacted streams. Both natural (low pH, high metal concentrations) and anthropogenic (forest drainage) stressors affected community composition of all three taxonomic groups, but only invertebrates showed an interactive response with communities differing between reference and impacted sites but only in the circumneutral region. Community concordance was relatively high among all pairs of communities, diatoms being most strongly concordant with the other groups. Although diatoms showed the greatest concordance with invertebrates, diatom and bryophyte communities responded most similarly to the environmental gradients. Our results implicate that communities typical to naturally acidic streams are at least equally sensitive to additional stressor as those in circumneutral streams. NORBS 2014, Oulanka Research Station, Finland 16 ASSESSING THE STRENGTH OF DISTANCE DECAY OF COMMUNITY SIMILARITY AT HIERARCHICAL SPATIAL SCALES Grönroos M.(1), Oksanen J. (2), Heino J. (3) (1) Natural Environment Centre, Finnish Environment Institute, Biodiversity, Oulu, Finland, [email protected] (2) Department of Biology, University of Oulu, Oulu, Finland, [email protected] (3) Natural Environment Centre, Finnish Environment Institute, Biodiversity, Oulu, Finland, [email protected] Environmental filtering and dispersal are two major factors structuring ecological communities. In stream systems, understanding the roles of these two factors could benefit, for example, restoration and bioassessment. One problem with correlative approaches is that high and limited dispersal rates may produce similar patterns. Here, we tested the idea that comparing the patterns at two hierarchical spatial scales would differentiate between high and low dispersal rates. For instance, high dispersal rates should lead to stronger spatial structuring at small scale compared to the larger scale and limiting dispersal should lead to an opposite situation. To study which factors structure stream insect communities, we used a dataset collected from ten streams draining into the River Oulankajoki (10 riffle sites from each stream, i.e. altogether 100 sites) and compared the decay of community similarity within streams (small scale) and across streams (large scale). The distance decay pattern along the geographical gradient suggested that high dispersal rates and environmental filtering are the main processes in this system. However, the distance decay pattern along the environmental gradient was more in line with what was expected for limiting dispersal. We conclude that more research is needed to better differentiate the processes structuring stream communities. NORBS 2014, Oulanka Research Station, Finland 17 ASSESSING THE IMPACTS OF FORESTRY AND PEAT MINING ON BOREAL HEADWATER STREAMS USING THE CHIRONOMID PUPAL EXUVIAE TECHNIQUE Nieminen M. L. (1,4), Ärje J. (2), Raunio J. (3), Meissner K. (4) (1) University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland, [email protected] (2) University of Jyväskylä, Department of Mathematics and Statistics, P.O. Box 35, FI-40014 University of Jyväskylä, Finland, [email protected] (3) Water and Environment Association of the River Kymi, Tapiontie 2C, FI-45160 Kouvola, Finland, [email protected] (4) Finnish Environment Institute (SYKE), Freshwater Centre, Survontie 9A, FI-40500 Jyväskylä, Finland, [email protected] Thirty percent of Finland’s total land area is covered by peatlands, 55% of which have been drained for forestry and 0.6% is used for peat production. Despite the small total area used, peat production is locally focused, and can thus have significant and measurable local impacts on aquatic ecosystems. Our aim was to test the effectiveness of the chironomid pupal exuvial technique (CPET) in the ecological assessment of small peatland draining headwater streams that receive drainage waters from forestry and peat mining areas. We collected data from 120 streams located within peatland covered boreal catchments. Community analyses were run together with GIS data determined for each sites’ catchment area and various environmental measurements from each site. New insights into the aquatic impacts of peatland use were obtained through the inclusion of Chironomidae genus-level information and areas for further research related to CPET and its use in headwater streams were identified. Although chironomid genus level information is currently largely underused, CPET is a viable option for freshwater monitoring of peatland use effects. NORBS 2014, Oulanka Research Station, Finland 18 PREDICTING THE CONSTRAINT EFFECT OF ENVIRONMENTAL CHARACTERISTICS ON MACROINVERTEBRATE DENSITY AND DIVERSITY USING QUANTILE REGRESSION MIXED MODEL Fornaroli R.(1), Cabrini R. (1), Sartori L. (1),Marazzi F. (1),Vracevic D. (1), Mezzanotte V.(1), Annala M. (2), Canobbio S. (1) (1) (2) DISAT, University of Milano-Bicocca, Piazza della Scienza 1, 20126, Milano, Italy, [email protected] Department of Biology, University of Oulu, PL 3000 90014, Oulu, [email protected] Various factors, such as habitat availability, competition for space, predation, temperature, nutrient supplies, presence of waterfalls, flow variability and water quality control the abundance, distribution and productivity of stream-dwelling organisms. Each of these factors can influence the relationship between the density of organisms and a single environmental gradient and inflate variability. In our study, we used quantile regression mixed models and Akaike’s information criterion as an indicator of goodness to examine two different dataset, one belonging to Italy and one belonging to Finland. In the Italian dataset, the relationships among five macroinvertebrate families and three physical habitat characteristics were studied (water velocity, depth and substratum size); in the Finnish dataset instead we have studied the relationships between taxa richness and 16 environmental characteristics (both chemical and morphological). We have found limiting relationships in both dataset. All these relationships were then validated using data different from those used in the model development phase. These relationships are quantitative and can be used to predict the range of macroinvertebrate densities or taxa richness as a function of environmental characteristics. They can be used for management purposes in habitat-based models and in the development of ecological indices. NORBS 2014, Oulanka Research Station, Finland 19 IDENTIFICATION GUIDE TO FRESHWATER MACROINVERTEBRATES OF ESTONIA Timm H. (1) (1) Centre for Limnology, Estonian University of Life Sciences, 61117 Rannu, Tartumaa, Estonia, [email protected] Macroinvertebrates are so diverse that their identification keys usually include only higher taxa (genera, families or orders), not the total fauna. In Estonian freshwaters, about 1600 different species of macroinvertebrates have been found so far. Two popular keybooks that comprise their major groups were published in Estonia (in 1956 and in 2008) but scientific guides for the whole fauna were still missing. The adequate foreign keys are scattered in numerous sources: about 20 different books or files were needed to identify the common environmental indicators. Even these keys miss some local species, although they introduce many exotic or redundant representatives. Thus, a new guide to Estonian freshwater macroinvertebrates was composed. It is best suited for last-instar larvae and water-living adults of the taxa with known bioindicative values. The guide includes 435 species or higher taxa and consists of 18 identification keys to different animal groups (both in Estonian and English). The keys are supplemented by 153 figures with >1500 original photos. List of names, environmental preferences, feeding types and frequencies of occurrence are added. NORBS 2014, Oulanka Research Station, Finland 20 RESTORATION OF SEDIMENT-STRESSED STREAMS HAS LITTLE EFFECTS ON BENTHIC BIODIVERSITY AND ECOSYSTEM FUNCTIONS Turunen J.T.(1), Muotka T. (2), Louhi P. (3), Tolkkinen M. (4), Aroviita J. (5) (1) Finnish Environment Institute, Freshwater Centre, PO Box 413, 90014 University of Oulu, Finland, [email protected] (2) University of Oulu, Department of Biology, PO Box 413, 90014 University of Oulu, Finland, [email protected] (3) University of Oulu, Department of Biology, PO Box 413, 90014 University of Oulu, Finland, [email protected] (4) Finnish Environment Institute, Freshwater Centre, PO Box 413, 90014 University of Oulu, Finland, [email protected] (5) Finnish Environment Institute, Freshwater Centre, PO Box 413, 90014 University of Oulu, Finland, [email protected] Excessive sedimentation due to intensive land use by agriculture and forestry is a predominant stressor to stream ecosystems. We studied the effects of small-scale catchment and in-stream restoration on benthic macroinvertebrate diversity and ecosystem functioning by comparing (i) restored streams (N=9), (ii) sediment-stressed streams (N=11), and (iii) near-natural streams (N=10) in northern Finland. The excessive sedimentation in our study area was mainly caused by sand originating from forest drainage activities. Macroinvertebrate community composition in the restored streams differed significantly from the near-natural streams, but not from the sedimentstressed streams. Similarly, macroinvertebrate diversity in the restored streams was significantly lower than in the near-natural streams, but did not differ from the sediment-stressed streams. However, ecosystem functioning measured by leaf litter breakdown rate was similar among the stream groups. The results thus indicate that sedimentation may degrade biodiversity but not necessarily key ecosystem functions. Overall, our results suggest that current management measures do not reduce streambed sedimentation sufficiently to enhance benthic biodiversity. NORBS 2014, Oulanka Research Station, Finland 21 RESTORATION OF RIVER SKJERN – DID BIODIVERSITY OF MACROINVERBRATES AND MACROPHYTES ‘IMPROVE’? Wiberg-Larsen P. (1), Baattrup-Pedersen A.(2), Kristensen E.A. (3), Kronvang B. (4), Hansen R.R. (5) (1) Institute of Bioscience, Aarhus Universitet, Vejlsøvej 25, DK-8600 Silkeborg, [email protected] Institute of Bioscience, Aarhus Universitet, Vejlsøvej 25, DK-8600 Silkeborg, [email protected] (3) Alectia A/S, Skanderborgvej 190, DK-8260 Viby J, [email protected] (4) Institute of Bioscience, Aarhus Universitet, Vejlsøvej 25, DK-8600 Silkeborg, [email protected] (5) Institute of Bioscience, Aarhus Universitet, C.F.Møllers Allé 8, DK-8000 Aarhus C, [email protected] (2) During 1999-2003 the lower 19 km of River Skjern and its valley was restored from its former highly regulated form, creating a meandering 25 km long reach, a stream delta, several new small tributaries, ponds and lakes, and wet meadows. The main purpose of the project was to reduce nutrient loading of the recipient, Ringkøbing Fjord, which was in a bad ecological state, Further, the project should restore the ecological quality of the river itself, and increase its biodiversity and recreational value. With a total price of 37 million €, the restoration project is the largest and most expensive in Denmark ever. But has it been worth the price? And have we obtained the goals and gained biodiversity? We have tried to answer these questions based on monitoring data from before, one year after, and ten years after the restoration. We also included unique historical data from before the regulation of the stream in the 1960’s in order to put the recent physical and biological development into a “pristine” perspective. The data and analyses included stream morphological parameters like total area, area of backwaters, width, depth, and substrate composition, whereas we biologically focused on macroinvertebrate EPT taxa and macrophytes. NORBS 2014, Oulanka Research Station, Finland 22 TENCH (TINCA TINCA) POPULATION SIZE REGULATING INVERTEBRATE NUMBERS; A CONSERVATION MANAGEMENT TOOL? –– EXPERIENCES FROM A SMALL BIRD LAKE ON THE ISLAND OF ÖLAND, SE SWEDEN Herrmann J (1), Ekstam B (1) (1) Linnaeus University, Department of Biology, SE-391 82 Kalmar, Sweden, [email protected] Large-scale reduction of (white)fish, thereby cascading to reduce phytoplankton production has worldwide been practiced for decades. In Knisa mosse, a shallow calcareous lake (18 ha) lake on the island of Öland, SE Sweden, the bottom-feeding fish tench (Tinca tinca) was introduced several decades ago, now dominating the fish community. Presumed to be a key species, controlling benthic and pelagial invertebrates, the tench population was over eight years (May-June) by netting substantially reduced from high densities, hopefully favouring invertebrates, these offering more food for ducks and waders (shore birds), Due to resource shortage, the tench population was allowed to re-increase. Standardized multi-mesh gill net fishing was performed before, during, and after the reduction years (August). Number of individuals and average size of caught tenches clearly declined, due to fishing, and reversed after fishing ceased. Several invertebrates, as chironomids, copepods, and cladocerans, also some mayfly, gastropod and mussel species, responded positively to tench reduction, i.e. increased in numbers. Unfortunately most of them also declined at tench recovery, while other bottom taxa showed less clear numerical changes. The ultimate objective, tench reduction favouring water birds, seems partially corroborated as an increase of ducks and geese, but last years’ of birds still seems unclear. NORBS 2014, Oulanka Research Station, Finland 23 UNRAVELLING THE DRIVERS OF FRESHWATER DIATOM BIODIVERSITY IN THE CONTEXT OF LARGE LAKE ASSESSMENT Vilmi A.(1), Karjalainen S. M. (2), Hellsten S. (3), Heino J. (4) (1) Finnish Environment Institute, P.O. Box 413, FI-90014, University of Oulu, [email protected] Finnish Environment Institute, P.O. Box 413, FI-90014, University of Oulu, [email protected] (3) Finnish Environment Institute, P.O. Box 413, FI-90014, University of Oulu, [email protected] (4) Finnish Environment Institute, P.O. Box 413, FI-90014, University of Oulu, [email protected] (2) Freshwater ecosystems face a variety of anthropogenic pressures, and different approaches and indicator groups are used to study the effects of those pressures on ecosystem structure and function. Diatoms are a widely used indicator group because they occur in all kinds of freshwater ecosystems and they react relatively quickly to changes in the environment. An ongoing debate centres on whether diatoms are ubiquitously dispersed or if they show spatially-structured biodiversity patterns. Understanding of the spatial structuring of diatom communities should also be associated with the assessment of lake ecosystem state. We aimed to determine the main drivers, both environmental and spatial, influencing the diatom assemblages, diatom indices and diversity indices. The statistical methods used were variation partitioning through distance-based RDA and distance-based linear models. Our results showed that spatial variables were more strongly related to our response variables than environmental variables. Thus, it seems that spatial factors are more important than water chemistry in determining freshwater diatom biodiversity in stony littorals of large lakes. These findings imply that mass effects (i.e. high dispersal rates) are likely to interfere with species sorting (i.e. environmental filtering). Acknowledging the importance of spatial processes is hence important in the context of large lake assessment. NORBS 2014, Oulanka Research Station, Finland 24 DO DIFFERENT FACETS OF LITTORAL MACROINVERTEBRATE DIVERSITY RESPOND SIMILARLY TO ECOLOGICAL GRADIENTS IN A LARGE BOREAL LAKE? Tolonen K.T.(1), Vilmi A.(2), Karjalainen S. M.(3), Hellsten S.(4), Heino J.(5) Finnish Environment Institute, P.O. Box 413, FI-90014 University of Oulu, Finland (all authors) 1 [email protected] 2 [email protected] 3 [email protected] 4 [email protected] 5 [email protected] Understanding of biodiversity patterns requires information about both environmental filtering and dispersal processes. In this context, the spatial scale of a study is essential because patterns and processes are scale dependent. Studies on the diversity and structure of lake assemblages have generally been focused on among-lake scales, while only few studies have examined within-lake patterns in biodiversity. In a large boreal lake, we sampled littoral macroinvertebrates from 81 littoral sites with stony substrate. We examined how different facets of biodiversity respond to 1) local environmental conditions and 2) within-lake spatial location of a site. Studied facets of diversity were species richness, diversity, evenness, taxonomic distinctness, taxonomic diversity, functional richness, diversity and functional evenness. Unexpectedly, we found that the diversity of littoral invertebrates was not clearly related to any of the measured water chemistry variables. Instead diversity was significantly spatially structured. This finding suggests that high dispersal rates between sites interfere with environmental filtering, thereby complicating understanding of diversity-environment relationships. Such spatially-structured variation in diversity and underlying mechanisms should explicitly be acknowledged in the assessment of lake ecological status. NORBS 2014, Oulanka Research Station, Finland 25 HABITAT COMPLEXITY ENHANCES THE STABILITY OF STREAM MACROINVERTEBRATE COMMUNITIES Huttunen K-L.(1), Mykrä H.(2), Astorga A.(3), Paavola R.(4), Muotka T.(1,5) (1) Department of Biology, University of Oulu, Finland Thule Institute, University of Oulu & Finnish Environment Institute, Freshwater Centre (3) Centro de Investigación de Ecosistemas de Patagonia, Chile (4) Thule Institute, University of Oulu (5) Department of Biology, University of Oulu & Finnish Environment Institute, Natural Environment Centre (2) We studied the temporal turnover of macroinvertebrate communities in 23 near-pristine boreal streams across 14 years using Bray-Curtis distance as the measure of among-year dissimilarity. We related temporal turnover to environmental stability, habitat complexity and productivity using multimodel inference. We hypothesized that high environmental stability, high habitat complexity and high productivity would lead to low temporal variation (high stability) in community structure. Effects of total abundance and species richness on temporal turnover were controlled for using rarefied samples and null models, respectively. The dominant factor related to temporal turnover was macrophyte cover (habitat complexity), followed by bed movement (environmental stability) and periphyton chl-a (productivity). Streams with high macrophyte cover supported more stable communities, whereas, against our expectations, the relationship between among-year similarity and bed disturbance index was negative, suggesting that disturbance acts as a habitat filter that selects for highly tolerant species. Most of the temporal variation in biological communities was caused by species with intermediate abundances. Instead, the core species of the community were generally present each year and exhibited limited inter-annual rank shifts. NORBS 2014, Oulanka Research Station, Finland 26 NORBS 2014, Oulanka Research Station, Finland