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Lentic ecosystems act as sentinels of climate change, and evidence exists that their sensitivity to warming varies along a latitudinal gradient. We assessed the effects of nutrient and water level variability on zooplankton community composition, taxonomic diversity and size structure in different climate zones by running a standardised controlled 6-months (May to November) experiment in six countries along a European north–south latitudinal temperature gradient. The mesocosms were established with two different depths and nutrient levels. We took monthly zooplankton samples during the study period and pooled a subsample from each sampling to obtain one composite sample per mesocosm. We found a significant effect of temperature on the community composition and size structure of the zooplankton, whereas no effects of water depth or nutrient availability could be traced. The normalised size spectrum became flatter with increasing temperature reflecting higher zooplankton size diversity due to higher abundance of calanoid copepods, but did not differ among depths or nutrient levels. Large-bodied cladocerans such as Daphnia decreased with temperature. Taxonomic diversity was positively related to size diversity, but neither of the two diversity measures demonstrated a clear pattern along the temperature gradient nor with nutrient and water levels. However, genus richness decreased at the warm side of the temperature gradient. Our experiment generally supports recent empirically based findings that a continuing temperature increase may result in lower genus richness and lower abundance of large-sized zooplankton grazers, the latter likely resulting in reduced control of phytoplankton.
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Effects of nutrient and water level changes
on the composition and size structure of zooplankton
communities in shallow lakes under different climatic
conditions: a pan-European mesocosm experiment
U
¨lku
¨Nihan Tavs¸anog
˘lu .Michal S
ˇorf .Konstantinos Stefanidis .Sandra Brucet .Semra Tu
¨rkan .
Helen Agasild .Didier L. Baho .Ulrike Scharfenberger .Josef Hejzlar .Eva Papastergiadou .
Rita Adrian .David G. Angeler .Priit Zingel .Ays¸e I
˙dil C¸akırog
˘lu .Arda O
¨zen .
Stina Drakare .Martin Søndergaard .Erik Jeppesen .Meryem Bekliog
˘lu
Received: 10 August 2016 / Accepted: 16 February 2017 / Published online: 28 February 2017
ÓSpringer Science+Business Media Dordrecht 2017
Abstract Lentic ecosystems act as sentinels of
climate change, and evidence exists that their sensi-
tivity to warming varies along a latitudinal gradient.
We assessed the effects of nutrient and water level
variability on zooplankton community composition,
taxonomic diversity and size structure in different
climate zones by running a standardised controlled
6-months (May to November) experiment in six
countries along a European north–south latitudinal
temperature gradient. The mesocosms were estab-
lished with two different depths and nutrient levels.
We took monthly zooplankton samples during the
study period and pooled a subsample from each
sampling to obtain one composite sample per meso-
cosm. We found a significant effect of temperature on
the community composition and size structure of the
zooplankton, whereas no effects of water depth or
nutrient availability could be traced. The normalised
size spectrum became flatter with increasing temper-
ature reflecting higher zooplankton size diversity due
to higher abundance of calanoid copepods, but did not
Handling Editor: Piet Spaak.
Electronic supplementary material The online version of
this article (doi:10.1007/s10452-017-9615-6) contains supple-
mentary material, which is available to authorized users.
U
¨. N. Tavs¸ anog
˘lu (&)A. I
˙.C¸akırog
˘lu
A. O
¨zen M. Bekliog
˘lu (&)
Limnology Laboratory, Department of Biological
Sciences, Middle East Technical University, C¸ ankaya,
Ankara 06800, Turkey
e-mail: unyazgan@gmail.com
M. Bekliog
˘lu
e-mail: meryem@metu.edu.tr
M. S
ˇorf
Faculty of Science, University of South Bohemia,
370 05 C
ˇeske
´Bude
ˇjovice, Czech Republic
e-mail: michal.sorf@centrum.cz
M. S
ˇorf J. Hejzlar
Biology Centre of the Czech Academy of Sciences,
Institute of Hydrobiology, 370 05 C
ˇeske
´Bude
ˇjovice,
Czech Republic
K. Stefanidis E. Papastergiadou
Department of Biology, University of Patras,
University Campus, 26504 Rio, Greece
e-mail: kstefani@chi.civil.ntua.gr
S. Brucet M. Søndergaard E. Jeppesen
Department of Bioscience and Arctic Research Centre,
Aarhus University, Vejlsøvej 25, 8600 Silkeborg,
Denmark
S. Brucet
Aquatic Ecology Group BETA Technology Centre,
ICREA (Catalan Institution for Research and Advanced
Studies) and University of Vic, Vic, Catalonia, Spain
S. Tu
¨rkan
Faculty of Science, Statistic Department, Hacettepe
University, Ankara 06800, Turkey
123
Aquat Ecol (2017) 51:257–273
DOI 10.1007/s10452-017-9615-6
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... Recent studies related to WLF have focused on the alteration of the SWBs' zooplankton diversity (Galir Balkić et al., 2018;Kuczyńska-Kippen and Pronin, 2018), abundance and biomass (Romo et al., 2004;Kuczyńska-Kippen et al., 2009;Š poljar et al., 2018b), and macroinvertebrate and fish community structure (Coops et al., 2003;Turić et al., 2015). SWB also create habitats for assessing the interactions and food web functioning of body-size dependent species (Brucet et al., 2010;Compte et al., 2012;Tavşanoglu et al., 2017). Body size may reflect changes in trophic state gradient (Jeppesen et al., 2011;Gutiérrez et al., 2017), temperature (Brucet et al., 2010), nutrient loading (Tavşanoglu et al., 2017;Ríos-Arana et al., 2019), and level of macrophyte coverage and habitat complexity (Basińska et al., 2010;Walsh et al., 2014). ...
... SWB also create habitats for assessing the interactions and food web functioning of body-size dependent species (Brucet et al., 2010;Compte et al., 2012;Tavşanoglu et al., 2017). Body size may reflect changes in trophic state gradient (Jeppesen et al., 2011;Gutiérrez et al., 2017), temperature (Brucet et al., 2010), nutrient loading (Tavşanoglu et al., 2017;Ríos-Arana et al., 2019), and level of macrophyte coverage and habitat complexity (Basińska et al., 2010;Walsh et al., 2014). Most previous studies have focused on the sizestructure of zooplankton and fish, and revealed that due to sizeselective predation (Meerhoff et al., 2007), fish can cause the loss of large-sized zooplankton, particularly cladocerans, shifting the balance in favour of small-sized species (Brucet et al., 2010;Tavşanoglu et al., 2017). ...
... Body size may reflect changes in trophic state gradient (Jeppesen et al., 2011;Gutiérrez et al., 2017), temperature (Brucet et al., 2010), nutrient loading (Tavşanoglu et al., 2017;Ríos-Arana et al., 2019), and level of macrophyte coverage and habitat complexity (Basińska et al., 2010;Walsh et al., 2014). Most previous studies have focused on the sizestructure of zooplankton and fish, and revealed that due to sizeselective predation (Meerhoff et al., 2007), fish can cause the loss of large-sized zooplankton, particularly cladocerans, shifting the balance in favour of small-sized species (Brucet et al., 2010;Tavşanoglu et al., 2017). Elimination of large-size cladocerans (efficient algivores), and domination of small-sized cladocerans and rotifers (less efficient filter-feeders) can contribute to a transition from a clear-water to a turbidwater state in SWB (Scheffer et al., 1993;Kuczyńska-Kippen, 2003;Jeppesen et al., 2012;Š poljar et al., 2018a). ...
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The littoral zone of shallow water bodies (SWB) is highly susceptible to water level fluctuations (WLF) caused by ongoing climate-related hydrologic regime changes. The present study assessed the macrozoobenthos structure in the littoral of three temperate SWB after pronounced WLF and accompanying reduction of macrophyte coverage caused by excessive precipitation. The three SWB differed in environmental conditions – S1 (transparent lake covered with submerged macrophytes dominated by Ceratophyllum demersum); S2 (turbid lake without macrophyte coverage) represented the two interconnected backwater basins of the Sutla River watershed; and SK (Škrčev kut oxbow; highly turbid lake sparsely covered by floating-leaved Nuphar lutea) located in the Krapina River watershed (Croatia). With the aim to disentangle the littoral food web structure, and interactions among environmental conditions as well as structural and functional traits of the littoral community within the three SWB, the macrozoobenthos functional traits, trophic guilds and body size were correlated with the littoral environmental conditions, and with the traits of the potential macrozoobenthos prey (zooplankton) and predators (fish). Our results suggest that the littoral macrozoobenthos assemblage responded to the water level increase mainly by the decline of macroinvertebrate diversity and abundance. Due to loss of habitat heterogeneity, in general, larger-sized macroinvertebrates dominated the littoral zone of turbid SWB, particularly with high WLF, while smaller-sized detritivores and grazers prevailed in the littoral zone of the transparent SWB covered by submerged macrophytes. The correlations between different macrozoobenthos, zooplankton and fish size classes indicated that the larger-sized predatory macroinvertebrates prey on smaller-sized zooplankters and avoid predation of mid-sized fish. On the other hand, the abundance of smaller-sized macroinvertebrate detritivores and grazers, which were significantly correlated with concentrations of suspended detritus and algae, prevailed in the SWB covered by submerged macrophytes. Within the macrophyte-covered littoral habitats, macroinvertebrates coexisted with small-sized fish and zooplankters as well as with large-sized pelagic zooplankters, likely seeking shelter from fish. We assume that the increased abundance of larger-sized specimens affected macroinvertebrates and fish within the littoral community upon water level increase. Such a pattern could be recognized as an indicative trait in the evaluation of ecosystem functioning. Furthermore, we conclude that the structural and functional traits of the SWBs’ littoral communities could help us predict the ecological consequences of the climate-induced WLF.
... These four measured variables (DO.P, Cu 2+ , BOD 5 , and Chl_a) are strongly associated with fishing site-1 and natural site. Phosphorus and Chl_a were also important measured variables in explaining the distribution of contemporary Cladoceran assemblages in the other published studies [48,53,59]. These studies suggest that nutrient enrichment affects the habitat conditions of Cladocera, including food quantity and quality, predation pressure, and macroinvertebrates. ...
... These studies suggest that nutrient enrichment affects the habitat conditions of Cladocera, including food quantity and quality, predation pressure, and macroinvertebrates. Tavşanoglu et al. [59] highlighted that increasing phosphorous content may be related to enhanced fish predation in large-sized Cladocerans. We observed decreases in Cladoceran species richness from fishing site-1 to fishing site-2 with increased phosphorous from fishing site-2 to fishing site-1. ...
Article
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Cladocerans are biological indicators of environmental changes. Their remains provide information on past changes in lake environments. We studied the correspondence between contemporary Cladocera assemblages and their subfossil remains from an oxbow lake. We sought to demonstrate that there were differences among the various sites of an oxbow lake with different utilization based on contemporary and subfossil Cladocera assemblages and physical–chemical variables. The oxbow lake’s two sides are used as fishing sites, where angling is the main activity. The middle site of the lake is under nature protection with high macrovegetation coverage. Contemporary and subfossil Cladocera assemblages were sampled from 21 sampling sites along the oxbow lake. Our research showed that the subfossil Cladocera assemblages had higher species richness and densities (36 taxa) than the contemporary species (29 taxa). We found one species of the Polyphemidae family only in the contemporary assemblage. Among the sites, Cladocera assemblages differed in their species composition and density. The highest densities were found in the second fishing site due to the appearance of the small-sized Bosmids. The relationship between Cladocerans and the physical–chemical variables showed that some variables, such as chlorophyll-a, biological oxygen demand, dissolved oxygen, copper, phosphide, and organic matter content, significantly affected Cladocera composition. We found that the subfossil Cladocera assemblage was significantly more diverse and abundant than the contemporary one, indicating that an integrated sampling may be sufficient to provide better results on the total species composition of the water body.
... In heated mesocosms without fish, Strecker et al. [24] found a decrease in zooplankton biomass, especially that of large-sized cladocerans, and they suggested it to reflect a taxonomic shift in the composition of phytoplankton towards larger sizes, including toxic and less edible cyanobacteria, as seen in several studies [25]. A pan-European mesocosm experiment also showed a decrease in large-sized zooplankton along an increasing temperature gradient [26]. Temperature itself may also affect body size. ...
... Small Cladocera and small Copepoda were higher in LN-A2 and large Cladocera lower in LN-A2+ compared with the controls (Table 2), suggesting a higher predation pressure with warming reflects size-selective predation (Hypothesis 3). Such a temperature effect on predation is observed both in cross-system mesocosm studies and in field data [23,26]. We also found a significantly lower taxon richness in HN-A2 and an increase in taxon evenness in LN-A2+ compared with their respective controls, but otherwise there was no observable warming effect. ...
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Shallow lakes are globally the most numerous water bodies and are sensitive to external perturbations, including eutrophication and climate change, which threaten their functioning. Extreme events, such as heat waves (HWs), are expected to become more frequent with global warming. To elucidate the effects of nutrients, warming, and HWs on zooplankton community structure, we conducted an experiment in 24 flow-through mesocosms (1.9 m in diameter, 1.0 m deep) imitating shallow lakes. The mesocosms have two nutrient levels (high (HN) and low (LN)) crossed with three temperature scenarios based on the Intergovernmental Panel on Climate Change (IPCC) projections of likely warming scenarios (unheated, A2, and A2 + 50%). The mesocosms had been running continuously with these treatments for 11 years prior to the HW simulation, which consisted of an additional 5 • C increase in temperature applied from 1 July to 1 August 2014. The results showed that nutrient effects on the zooplankton community composition and abundance were greater than temperature effects for the period before, during, and after the HW. Before the HW, taxon richness was higher, and functional group diversity and evenness were lower in HN than in LN. We also found a lower biomass of large Cladocera and a lower zooplankton: phytoplankton ratio, indicating higher fish predation in HN than in LN. Concerning the temperature treatment, we found some indication of higher fish predation with warming in LN, but no clear effects in HN. There was a positive nutrient and warming interaction for the biomass of total zooplankton, large and small Copepoda, and the zooplankton: phytoplankton ratio during the HW, which was attributed to recorded HW-induced fish kill. The pattern after the HW largely followed the HW response. Our results suggest a strong nutrient effect on zooplankton, while the effect of temperature treatment and the 5 • C HW was comparatively modest, and the changes likely largely reflected changes in predation.
... Considering that our goal was to evaluate the actual similarities between communities rather than emphasizing the role of rare species, we used untransformed proportional species abundances to explore the similarities between the sites and test the differences between the three lakes [24]. We used the method of "analysis of similarity" (ANOSIM,) based on the Bray-Curtis dissimilarity measure with 999 permutations [25], and we also performed a non-metric multidimensional scaling analysis (NMDS) to reflect the ordination of sites and reduce the deviations of sample size on ANOSIM. NMDS was performed via the "metaMDS" function, and the data were transformed with the Hellinger standardization method via "decostand" function. ...
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... Physical variability across environmental gradients, biotic effects mediated by top-down or bottom-up forces as well as the trade-offs by constraining traits on species involved determine zooplankton community structure in shallow lakes (Wiggins et al. 1980;McQueen et al. 1986;Tilman 1987;Wellborn et al. 1996;Meerhoff et al. 2012;Batzer and Boix 2016;Gascón et al. 2016;Tavşanoğlu et al. 2017). Dominances of single species in zooplankton assemblages are often described as a consequence of competitive exclusion under low predation pressure (Gliwicz et al. 2010;Kerfoot and DeMott 1984) or of extreme environmental constraints, such as those caused by temperature (Herbert and Hann 1986;Lau et al. 2020), temperature fluctuations (Zhang et al. 2018) or salinity Waterkeyn et al. 2008;Brucet et al. 2009Brucet et al. , 2012. ...
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... Contrary to our results, some experimental studies reported either no effect of nutrient addition on zooplankton size variance (Tavşanoğlu et al. 2017) or a negative effect on both average size and size diversity in high-nutrient mesocosms (Šorf et al. 2015). These contrasting results could potentially be explained by the limited nutrient range used in these experiments (35 to 103 µg L -1 and 13.3 to 285 µg L -1 , respectively) and by fish predation pressure on zooplankton community-a factor not considered in our study. ...
Thesis
Full-text available
Given the unprecedented and growing threats to inland waters — eutrophication, cyanobacterial blooms, over-exploitation, and climate change — from multiple human activities, biodiversity is decreasing at faster rates in freshwater ecosystems than in marine or terrestrial. Since the early 1990s, hundreds of studies attempted to explain how ecosystems respond to biodiversity loss and how changes in biodiversity scale up to affect ecosystem functioning, as well as the provision of goods and services to humans. Recent studies have demonstrated that such biodiversity responses are commonly trait-mediated and the effects of communities on ecosystem functioning also depend on species traits. However, it remains unclear to what extent such biodiversity responses translate into changes in the rates of many ecosystem processes in naturally assembled communities. In this doctoral dissertation, I aimed at evaluating the effects of nutrient availability and cyanobacteria dominance on structure and composition of plankton communities (phytoplankton and zooplankton), and on two important ecosystem functions in aquatic systems: phytoplankton resource use efficiency (RUE) of limiting nutrients — phosphorus and nitrogen — and zooplankton top-down control of algae. For this, I structured this doctoral dissertation in three chapters to explore the mechanisms that underlie biodiversity-ecosystem functioning (B-EF) relationships, using a combination of experimental and fieldwork approaches, together with multiple aspects of biodiversity (i.e., taxonomic and functional diversity). In the first chapter, I and my coauthors analyzed the relationship between different measures of phytoplankton diversity, temporal turnover and RUE using 8-years monitoring data set from a cyanobacteria-dominated subtropical lake, which is now experiencing a shift in the trophic state from oligo-mesotrophic to eutrophic. Additionally, we aimed at evaluating the effect of resource availability on phytoplankton community structure and RUE. In the second chapter, using 1-year monitoring data set from the same lake, we evaluated the relative importance of size-based and taxon-based approaches in explaining the strength of zooplankton top-down control on algae, and also aimed at disentangling the mechanism by which zooplankton body size drives such ecosystem function. Finally, in the third chapter, we used an experimental metacommunity approach that simulated typical gradients of productivity and plant structural complexity to test how zooplankton body size diversity and composition responded to such gradients and whether and how such trait responses impacted top-down control of algae. Through these three chapters, we demonstrated that under environmental changes (i.e., nutrient increase and prolonged cyanobacteria dominance) approaches based on body size and taxonomic richness complement each other in explaining variation in zooplankton top-down control. Our results clearly indicate that zooplankton body size explains a substantial and independent part of the variance in top-down control, which corroborates several studies demonstrating the role of zooplankton body size to control phytoplankton biomass. But contrary to our expectations, species richness also plays a role, indicating that species richness may adequately represent some unmeasured traits that also influence ecosystem functioning. Moreover, we demonstrated that different aspect of biodiversity might have divergent responses and divergent effects on ecosystem functioning depending on environmental perturbation, which highlight the importance of considering multiple aspects of biodiversity — taxonomic and functional approaches — in B-EF research. Overall, our results illustrated the potential for trait-based approaches to reveal biodiversity responses to environmental change and their generalizable effects on ecosystems. Furthermore, given the lack of large grazers in tropical and subtropical regions, and the evidence that Cyanobacteria dominance will increase in freshwater ecosystems under the predicted future climate, the results herein highlight the concern about the energy flow in aquatic systems dominated by Cyanobacteria.
... Decosta et al. (1983) observed the effect of phosphorus on phytoplankton and zooplankton, concluding that an increase in phosphorus led to an increase of phytoplankton biomass and in turn decreased the diversity and abundance of zooplankton. A justification for this phenomenon is mainly the competition that exists for the space between zooplankton and phytoplankton (Tavşanoğlu et al., 2017). The increase in phytoplankton limits the entry of light and, consequently, decreases the sources of heat energy in the photic zone (competition by niche or niches overlap (Hoffmann, 2017)). ...
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Tropical lakes are less numerous than temperate lakes because of glacial origin are rare in the tropics. Lakes of riverine origin are probably more common than any other type in the tropics. For lakes of a given type and size, latitudinal trends can be traced mainly to latitudinal gradients in minimum monthly solar irradiance. Tropical lakes of moderate to great depth are predominantly warm monomictic, and show great regularity in seasonal mixing, which typically coincides with the hemispheric winter. Stratification is seasonally persistent, but is less stable than at higher latitudes, and the amount of heat exchange required to cause important changes in stability is also smaller than at higher latitudes. Efficiency of nutrient cycling is high at low latitudes because of intraseasonal deep mixing combined with high mean temperatures, which support higher nutrient regeneration rates. Primary production is about twice as high on a given nutrient base as it would be at higher latitudes, primarily because of efficient nutrient cycling combined with higher mean temperatures and greater stability in solar irradiance. Nitrogen is more often a limiting element for autotrophs in the tropics. Phytoplankton, zooplankton, and benthic communities are no more complex at low than at high latitudes. -from Author
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The first edition of this book has established itself as one of the leading references on generalized additive models (GAMs), and the only book on the topic to be introductory in nature with a wealth of practical examples and software implementation. It is self-contained, providing the necessary background in linear models, linear mixed models, and generalized linear models (GLMs), before presenting a balanced treatment of the theory and applications of GAMs and related models. The author bases his approach on a framework of penalized regression splines, and while firmly focused on the practical aspects of GAMs, discussions include fairly full explanations of the theory underlying the methods. Use of R software helps explain the theory and illustrates the practical application of the methodology. Each chapter contains an extensive set of exercises, with solutions in an appendix or in the book’s R data package gamair, to enable use as a course text or for self-study.