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Introduction
My main interest is understanding the complexity of ecological systems, particularly using freshwater fish as a main study group. In this sense, I tackle questions such as who eats whom or who controls whom and answer them using theoretical backgrounds and quantitative analyses. I perform advanced statistical tools to explain community patterns and species coexistence.
Current institution
Paul Sabatier University - Toulouse III | UPS Toulouse
Laboratoire Evolution et Diversité Biologiques (EDB)
Current position
PostDoc Position
Skills and Expertise
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Universidade Federal de Mato Grosso do Sul
Universidade Federal do Rio Grande do Norte
Swedish University of Agricultural Sciences
Universitat de Girona
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Universidad de Navarra
Imperial College London
French National Institute for Agriculture, Food, and Environment (INRAE)
Universidade Federal de Mato Grosso do Sul
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Projects
Projects (2)
A timely look at effects of agriculture on fluvial dissolved organic matter: the role of hydrology (AGRHYDROM)
AGRHYDROM is a collaborative project carried out by young researchers of the Iberian Association of Limnology in order to promote the networking between interdisciplinary young scientists. The main objective of the project is to study the combined effect of agriculture and seasonal hydrology on nutrients and DOM quantity, composition and bioavailability in temporary streams.
Urban algae - Ecological Status and the Perception of Ecosystem Services of Urban Ponds
The Urban algae project aims to study the ecological status of urban ponds and their ecosystem services together with the citizen´s perceptions. To this end, we will combine a sampling campaign during the summer 2018 in multiple locations across Europe with an online citizen survey questionnaire. With this set-up, we want to know what the public thinks about their ponds and if this is related to the ecological status of the relevant ponds. The second important goal of this initiative is to create an international collaborative network, encouraging young and early career scientists in Europe. This project provides an excellent chance to actively participate in an interdisciplinary project and meet other young researchers!
Research
Research Items (32)
The structure and functioning of Arctic ecosystems have been drastically modified by global warming, with fish species potentially performing habitat shifts such as the northern expansion of generalist and warm-adapted species. The freshwater fish species Arctic charr (Salvelinus alpinus, hereafter charr) plays a key role in Arctic lake food webs, but sticklebacks (Gasterosteus aculeatus) may impact the trophic position (TP) of charr by affecting their habitat choice and food resources. In the present study, we used multiple regression analyses to examine the role of lake morphology (i.e., depth and area) and the influence of sticklebacks on the TP of charr (estimated from δ 15 N and δ 13 C) sampled in nine Arctic lakes in Western Greenland between 2011 and 2013. Results showed that charr populations exhibited larger TP values when co-occurring with sticklebacks. Specifically, for larger and deeper lakes, a significant positive effect on TP values was observed for medium-sized (25 to 35 cm) charr. Moreover, the TP of sticklebacks had a null effect on the TP values of the largest charr (> 40 cm), suggesting that the largest-sized charr individuals did not prey on sticklebacks. We conclude that charr undergoes flexible ontogenetic trophic trajectories depending on the species composition of the Arctic fish community structure (here presence or absence of sticklebacks) and abiotic lake features.
The COVID‐19 pandemic has heavily impacted academics’ professional and personal lives, forcing many research groups (labs) to shift from an academic system primarily based on in‐person work to an almost full‐time remote workforce during lockdowns. Labs are generally characterized by a strong lab culture that underpins all research and social activities of its members. Lab culture traditionally builds on the pillars of in‐person communication, knowledge sharing, and all social and professional activities that promote collaboration, team building, scientific productivity, and well‐being. Here, we use the experience of our research group facing the COVID‐19 pandemic to illustrate how proactively reinforcing lab culture and its positive outcomes have been essential to our lab when transitioning from an in‐person to a remote lab environment, and through its ongoing evolution toward a hybrid remote/in‐person model. We argue that the proactive promotion of lab culture in research groups can foster academic resilience during crises, helping research groups to maintain their capacity to conduct scientific activities while preserving a sustainable life/work balance and a healthy mental condition. The Covid‐19 pandemic crisis has forced many research groups to move from an academic system based on in‐person work and characterized by a strong lab culture to a fully remote workforce. We illustrate how reinforcing lab culture has been essential for our research group when transitioning from an in‐person to a remote lab. We argue that proactively promoting lab culture is essential for supporting academic resilience during crises and to help research groups maintain scientific activity and preserve a sustainable life/work balance.
We provide a unique fish individual body size dataset collected from our own sampling and public sources in north-eastern Spain. The dataset includes individual body size measures (fork length and mass) of 12,288 individuals of 24 fish species within 10 families collected at 118 locations in large rivers and small streams. Fish were caught by one-pass electrofishing following European standard protocols. The fish dataset has information on the local instream conditions including climatic variables (i.e., temperature and precipitation), topography (i.e., altitude), nutrient concentration (i.e., total phosphorus and nitrates), and the IMPRESS values (a measure of cumulative human impacts in lotic ecosystems). The potential uses of this new fish dataset are manifold, including developing size-based indices to further estimate the ecological status of freshwater ecosystems, allometric models, and analysis of variation in body size-structure along environmental gradients.
The structure and functioning of Arctic ecosystems have been drastically modified by global warming, with fish species potentially performing habitat shifts such as the northern expansion of generalist and warm-adapted species. The freshwater fish species Arctic charr (Salvelinus alpinus, hereafter charr) plays a key role in Arctic lake food webs, but sticklebacks (Gasterosteus aculeatus) may impact the trophic position (TP) of charr by affecting their habitat choice and food resources. In the present study, we used multiple regression analyses to examine the role of lake morphology (i.e., depth and area) and influence of sticklebacks on the TP of charr (estimated from δ15N and δ13C) sampled in nine Arctic lakes in Western Greenland between 2011 and 2013. Results showed that charr populations exhibited larger TP values when co-occurring with sticklebacks. Specifically, for larger and deeper lakes, a significant positive effect on TP values was observed for medium-sized (25 to 35 cm) charr. Moreover, the TP of sticklebacks had a null effect on the TP values of the largest charr (> 40 cm), suggesting that the largest-sized charr individuals did not prey on sticklebacks. We conclude that charr undergo flexible ontogenetic trophic trajectories depending on the species composition of the Arctic fish community structure (here presence or absence of sticklebacks) and abiotic lake features.
Environmental and geographical factors are known to influence the number, distribution and combination of species that coexist within ecological communities. This, in turn, should influence ecosystem functions such as biomass conservation, or the ability of a community to sustain biomass from small to large organisms. We tested this hypothesis by assessing the role of environmental factors in determining how biomass is conserved in over 600 limnetic fish communities spread across a broad geographic gradient in Canada. Comprehensive and accurate information on water conditions and community characteristics such as taxonomy, abundance, biomass and size distributions were used in our assessment. Results showed that species combinations emerge as one of the main predictors of biomass conservation among the effects of individual species and abiotic factors. Our study highlights the strong role that geographic patterns in the distribution of species can play in shaping key ecosystem functions, with consequences for ecosystem services such as the provision of harvestable fish biomass.
This study investigated the effects of environmental variation on fish diversity patterns in two coastal streams in northwestern Ecuador. Specifically, we examined the role of topography, instream conditions (pH, conductivity), and human influence (land-use modifications) on fish species richness, diversity and evenness as well as body size diversity and size evenness. Study region comprised 19 sites sampled bimonthly during the dry and wet seasons in 2016–2017. The results showed that the contribution of each measure of fish diversity responded differently to the local drivers. For size-based metrics, fish assemblages displayed greater size diversity (more diversity of body sizes) at lower pH and conductivity levels. Taxonomic metrics showed a negative relationship between the number of species and the downstream–upstream gradient. In both measures of diversity, human influence negatively affected size evenness and Shannon diversity, with less equitable abundance distribution and fewer species in more human-altered locations. These results improve our understanding of how assembly processes operate in shaping local fish assemblages in Neotropical coastal streams.
This study investigated the effects of environmental variation on fish diversity patterns in two coastal streams in northwestern Ecuador. Specifically , we examined the role of topography, instream conditions (pH, conductivity), and human influence (land-use modifications) on fish species richness, diversity and evenness as well as body size diversity and size evenness. Study region comprised 19 sites sampled bimonthly during the dry and wet seasons in 2016-2017. The results showed that the contribution of each measure of fish diversity responded differently to the local drivers. For size-based metrics, fish assemblages displayed greater size diversity (more diversity of body sizes) at lower pH and conductivity levels. Taxonomic metrics showed a negative relationship between the number of species and the downstream-upstream gradient. In both measures of diversity, human influence negatively affected size evenness and Shannon diversity, with less equitable abundance distribution and fewer species in more human-altered locations. These results improve our understanding of how assembly processes operate in shaping local fish assemblages in Neotrop-ical coastal streams.
Aquatic ecosystems are strongly body-size structured with a decline of numerical abundance with increasing body size (hereafter, the size spectrum).Marine and lake fish studies have reported consistent variations of size spectra in relation to environmental conditions and biotic composition, but little is known about streamfishes. Accordingly, in this studywe test several hypotheses about the effects of local water conditions, biotic introductions and cumulative pressures (measured as the IMPRESS index) on the fish size-spectrum slope (that is, the linear rate of decline of fish abundance as body size increase in a log-log scale) and the size-spectrum intercept (commonly used as proxy for carrying capacity) among 118 local fish assemblages in streams of the NE Iberian Peninsula. To our knowledge, this is the first time that an extensive river fish dataset is used in a dendritic network to cover systematic changes of size-spectrumparameters.Wefind that the slope and intercept of the fish size spectrum are negatively correlated with nutrient concentration (mainly total phosphorus), with a greater relative abundance of small fishes but a decline of overall carrying capacity. Moreover, fish assemblages with greater relative abundance of non-native species have flatter size-spectrum slopes. In contrast, the IMPRESS index and climate-related variables are poor predictors of the shape of the fish size spectra. This study contributes to better understanding of themain factors structuring fish assemblages in lotic environments of the Iberian Peninsula. We encourage more research on this line to further explore the use of fish size structure to evaluate the ecological health of riverine ecosystems.
Aphanius iberus is an endemic cyprinodontoid fish species of Mediterranean ponds in danger of extinction. In this study, we studied some abiotic and biotic factors that can influence A. iberus’s size structure and density in Mediterranean brackish ponds. We sampled fish using fyke nets in 10 ponds of Empordà (Spain) during the spring season. Our results showed that a better ecological status (according to the Water Quality of Lentic and Shallow Ecosystems (QAELS) index), pond’s depth and pond’s isolation (reflected by an increase in total nitrogen) were related to larger individual sizes and more size-diverse populations. Increasing the salinity is known to help the euryhaline A. iberus acting as a refuge from competitors. Nevertheless, our results showed that higher conductivities had a negative effect on A. iberus’s size structure, leading to a decrease in the mean and maximum size of the fish. Fish abundance (expressed as captures per unit of effort (CPUE)) seemed to increase with increasing the pond’s depth and total nitrogen (the latter reflecting pond isolation). In conclusion, our results suggest that achieving a better pond ecological status may be important for the conservation of endangered A. iberus, because better size-structured populations (i.e., larger mean and average lengths) were found at higher water quality conditions.
New data about trichomycetes from the North-eastern Iberian Peninsula is reported, including the description of two new species of Amoebidiales and one species of Harpellales: Paramoebidum contortum from Baetidae and Ephemerellidae (Ephemeroptera, mayflies) nymphs, Paramoebidium lateralis from Capniidae and Leuctridae nymphs, and Ejectosporus chimaera from Capniidae nymphs (Plecoptera, stoneflies). Both species of Paramoebidium are characterized by their particular thallial and holdfast structures. We report the occurrence of a thallus that originated from the fusion of what seems to be two cystospores in a specimen of P. lateralis. This could be an important addition in the study of Amoebidiales, since thallial fusion processes were previously unknown for this order. The new species of Harpellales, Ejectosporus chimaera, is a rare dimorphic species with a narrow distribution, which shares similarities with the genera Genistelloides and Lancisporomyces. New geographic records for the Iberian Peninsula are also provided, including Paramoebidium corpulentum, P. hamatum (Amoebidiales), Glotzia centroptili, Smittium lentaquaticum, and Sm. mucronatum (Harpellales). Comments are provided for each of the species, together with photographs, to illustrate each taxon. © 2018 J. Cramer in Gebr. Borntraeger Verlagsbuchhandlung, Stuttgart, Germany.
Fish can alter food web structure through trophic cascades. While most studies conducted in oligotrophic subarctic lakes show strong top–down control on consumers in the presence of fish, several studies undertaken in eutrophic subarctic Lake Mývatn, Iceland, suggest that it is consumer–resource interactions that drive the whole-lake community. Here, we used stable isotopes of carbon and nitrogen from the main food web compartments derived from a 3-month in situ-controlled mesocosm experiment involving two treatments (with and without fish) with three replicates each to determine the effects of fish on the trophic structure of the Lake Mývatn food web. We found that the whole food web trophic structure shifted towards the upper part of the water column (more planktonic habitat) in fishless enclosures. Additionally, the trophic niche of organisms occupying the base of the food web became more diversified when fish were absent, and the trophic redundancy of all taxa decreased (more dissimilar trophic niches). Stronger top–down effects may also result from global warming, producing increased abundance of planktivorous fish in subarctic lakes. Our results indicate that this could lead to a shift in trophic niche and reduced trophic diversity of most food web organisms.
Size structure of organisms at logarithmic scale (i.e. size spectrum) can often be described by a linear function with a negative slope; however, substantial deviations from linearity have often been found in natural systems. Theoretical studies suggest that greater nonlinearity in community size spectrum is associated with high predator–prey size ratios but low predator‐prey abundance ratios; however, empirical evaluation of the effects of predator–prey interactions on nonlinear structures remains scarce. Here, we aim to empirically explore the pattern of the size‐specific residuals (i.e. deviations from the linear regression between the logarithmic fish abundance and the logarithmic mean fish size) by using size spectra of fish communities in 74 German lakes. We found that nonlinearity was strong in lakes with high predator–prey abundance ratios but at low predator–prey size ratios. More specifically, our results suggest that only large predators, even if occurring in low abundances, can control the density of prey fishes in a broad range of size classes in a community and thus promote linearity in the size spectrum. In turn, the lack of large predator fishes may cause high abundances of fish in intermediate size classes, resulting in nonlinear size spectra in these lakes. Moreover, these lakes were characterized by a more intense human use including high fishing pressure and high total phosphorus concentrations, which have negative impacts on the abundance of large, predatory fish. Our findings indicate that nonlinear size spectra may reflect dynamical processes potentially caused by predator‐prey interactions. This opens a new perspective in the research on size spectrum, and can be relevant to further quantify the efficiency of energy transfer in aquatic food webs. This article is protected by copyright. All rights reserved.
Invasion of non-native species is considered a major threat to global biodiversity. Here we present a comprehensive overview of the occurrence, richness and biomass contribution of non-native fish species in 1943 standing water bodies from 14 countries of the Western Palearctic, based on standardised fish catches by multi-mesh gillnetting. We expected strong geographical gradients to emerge in the occurrence of non-natives. We further hypothesised that the contribution by nonnatives to the local fish community biomass was correlated with local richness and the trophic level of native and non-native species. Non-native fish species occurred in 304 of 1943 water bodies (16%). If the average number of occupied water bodies per country was weighted by number of water bodies per country, the grand mean occurrence of non-natives in Western Palearctic water bodies was 10%. Exotic (non-native to the Palearctic) and translocated (non-native only to parts of the Palearctic) species were found in 164 (8.4%) or 235 (12.1%) of the water bodies, respectively. The occurrence and local richness of non-native fish species increased with temperature, precipitation and lake area and were substantially higher in reservoirs than in natural lakes. High local biomass contributions of non-native species were strongly correlated with low richness of native species and high richness of non-native species, whereas the trophic level of the fish species had only a weak effect. Single non-native species rarely dominated community biomass, but high biomass contributions and thus strong community and ecosystem impacts can be expected if several non-native species accumulate in a water body.
1. Trophic cascade studies have so far mostly focused on changes in the abundance, biomass, or average size of prey and predators. In contrast, individual size-based interactions, playing a key role in the trophic structure and functioning of aquatic ecosystems, have been less explored. 2. We conducted a 3-month in situ experiment in Lake Myvatn, Iceland, with two fish treatments (with and without fish, Gasterosteus aculeatus). After the first month of the experiment, Anabaena blooms appeared in the lake. We studied the effects of fish predation and occurrence of cyanobacteria blooms on the individual size structure (i.e. the distribution of the number of organisms over a size range) of zooplankton and phytoplankton. We also assessed the potential consequences for trophic transfer efficiency (TTE) (measured as the predator to prey biomass ratio) in the planktonic food web. 3. Our results showed that fish predation and cyanobacteria bloom had a negative relationship with size diversity of zooplankton, which became dominated by small-sized individuals in both cases. The phytoplankton size diversity changed over time particularly due to the blooming of large-sized Anabaena, and its increase was apparently mainly driven by changes in resources. 4. Low zooplankton size diversity related to fish predation reduced TTE, particularly in the enclosures with fish. This may be because low zooplankton size diversity represents a lower partition of resources among consumers, thereby decreasing the trophic energy transfer. With the occurrence of Anabaena bloom, high phyto-plankton size diversity coincided with a lower energy transfer in all enclosures likely due to reduced zooplankton grazing when large-sized colony-forming Ana-baena dominated. 5. In conclusion, our results indicate that both top-down and bottom-up forces significantly influence the size structure of planktonic communities. The changes in size structure were related to shifts in the energy transfer efficiency of the Lake Myvatn food web. Thus, our study underpins the importance of taking into account size-based interactions in the study of trophic cascades, particularly in a
Body size, coupled with abundance and taxonomy, may help to understand the mechanisms shaping community structure. Since the body size of fish is closely related to their trophic niche, size diversity (based on individual body size) of fish communities may capture intraspecific variations in fish trophic niches that are not detected by species diversity. Thus, the relationship between size diversity and species diversity may help to integrate variation at both intraspecific and interspecific levels. We studied the relationship between species diversity and size diversity as a measure of the degree of overlap in size among species and thereby the potential overlap in niches in a community. We hypothesized that the relationship between size diversity and species would be different across the European continent due to different levels of size overlap in fish communities. The data were derived from samplings of fish communities using standardised benthic gill nets in 363 lakes. At the continental scale, size diversity increased with species diversity; at the ecoregion scale, the slope of the relation changed across the continent, with the greatest mismatch occurring in northern Europe where communities comprised only one or a few species, but each of which exhibited a great range in size. There was an increase in slope towards the south with significant relations for four out of six ecoregions. The steeper size diversity-species diversity slope at lower latitudes is attributable to a lower overlap in fish size and thus likely to finer niche separation. Our results also suggest that size diversity is not a strong surrogate for species diversity in European lake fish communities. Thus, particularly in fish communities composed of few species, measuring size diversity may help to detect potential functional variation which may be neglected by measuring species diversity alone.
Effects of fish predation on consumers tend to be particularly strong in oligotrophic Arctic and sub-Arctic lakes. However, it remains unclear whether the fish influence the trophic structure and dynamics of naturally eutrophic lakes in these cold environments with simple food web structures. To study this, we conducted a 3-month in situ-controlled experiment in sub-Arctic Lake Myvatn, Iceland. We used the planktivorous fish three-spined sticklebacks (Gasterosteus aculeatus) as the main top predator. The cladocerans Eurycercus lamellatus and Acroperus harpae were significantly associated with fishless enclosures, whereas the rotifers Polyarthra sp. and Filinia terminalis were significantly associated with the fish enclosures. Fish predation led to a significant increase in phytoplankton biomass and a reduction in the zooplankton:phytoplankton biomass ratio, the mean zooplankton length and cladoceran mean biomass. Fish effects might have been stronger if a bloom of Anabaena in August had not overridden potential cascading effects. We argue that both topdown and bottom-up forces are important for structuring the communities in the lake. Our results suggest that Arctic and sub-Arctic lakes may undergo important changes in trophic dynamics if they get warmer and more nutrient rich as expected with the global climate change.
Metacommunity approaches are becoming popular when analyzing factors driving species distribution at the regional scale. However, until the popularization of the variation partitioning technique it was difficult to assess the main drivers of the observed patterns (spatial or environmental). Here we propose a new framework linking the emergence of different metacommunity structures (e.g., nested, Gleasonian, Clementsian) to spatial and environmental filters. This is a novel approach that provides a more profound analysis of how both drivers could lead to similar metacommunity structures. We tested this framework on 110 sites covering a strong environmental gradient (i.e., microcrustacean assemblages organized along a salinity gradient, from freshwater to brackish water wetlands). First we identified the metacommunity structure that better fitted these microcrustacean assemblages. Then, we used hierarchical variation partitioning to quantify the relative influences of environmental filters and the distance among wetlands on the identified structure. Our results showed that under strong environmental filtering metacommunity structures were non-random. We also noted that even passive dispersers, that are supposed to be poorly spatially filtered, showed spatial signals at a large geographical scale. However, some difficulties arose when inferring biotic interactions at finer-scale spatial signals. Overall, our study shows the potential of elements of metacommunity structure combined with variation partition techniques to detect environmental drivers and broadscale patterns of metacommunity structure, and that some caution is needed when interpreting finer-scale spatial signals.
We studied fish size structure by using mean size, size diversity, and the slope of linear size spectra of six common European fish species along large-scale environmental gradients. We further analyzed the response of these three size metrics to environmental variables and to density-dependent effects, i.e., relative estimates of abundance (catch per unit effort, CPUE). We found differences in the strength of main predictors of size structure between the six species, but the direction of the response was relatively similar and consistent for most of the size metrics. Mean body size was negatively related to temperature for perch (Perca fluviatilis), roach (Rutilus rutilus), and ruffe (Gymnocephalus cernuus). Lake productivity (expressed as total phosphorus concentration) and lake depth were also predictors of size structure for four of six species. Moreover, we found a strong density dependence of size structure for all species, resulting in lower mean body size and size diversity and steeper size spectra slopes when density dependence increases. This suggests that density dependence is a key driver of fish size structure.
Large scale studies on individual size distribution of fish have primarily been done at community level, but little attention is paid at species level. We described fish size structure by using mean size, size diversity and the slope of linear size spectra of six common European fish species to compare whether these metrics responded to the same large-scale continental gradients. As predictors, we included several environmental variables and relative estimates of abundance (catch per unit effort) as indicator of density-dependent effects. We found differences in the strength of the main predictors of size structure between the six species, but the direction of the response was relatively similar and consistent for most of the size metrics. Temperature variations across Europe weakly induced the similar negative response to the size metrics for most species. However, we found an unexpectedly strong density dependence of size structure in all species, resulting in lower mean body size and size diversity and steeper size spectra slopes. This suggests that the density-dependent effect is so far an underestimated driver of fish size structure.
Contribution to the knowledge of the distribution of Chaoborus species (Diptera: Chaoboridae) in the NE Iberian Peninsula, with notes on the spatial and temporal segregation among them Phantom midges are characteristic inhabitants of standing waters and are well known for their diel migrations. Despite the extensive body of literature covering their ecology, there are still knowledge gaps with regards to the factors that determine their distribution. Furthermore, although spatial and temporal segregation patterns among chaoborids have long been reported, the prevalence of such patterns in shallow waters remains unclear. We investigated the distribution of Chaoborus species, as well as their spatial and temporal segregation and diel mesohabitat migration, in the NE Iberian Peninsula. We detected three Chaoborus species (C. crystallinus, C. pallidus and C. flavicans), with the latter being the most dominant, and co-occurrences among these species being very low. C. flavicans did not perform diel horizontal migrations, although in one of the ponds it showed high affinities to vegetated areas during both day- and night-time, similar to its potential predators. Therefore, although we did not observe the role of diel horizontal migrations as an antipredator mechanism in shallow water bodies, aquatic vegetation could confer refuge to the chaoborid larvae. Key words: Chaoborus, shallow waterbodies, diel mesohabitat migration, segregation, Iberian Peninsula.
Variations in the size structure of fish communities were explored at European scale along gradients of climate, morphometry, productivity and fish community structure in more than 1800 lakes. Size metrics used were average fish body size, individual size distributions and size diversity. Analyses were conducted at both continental and regional scale. We found changes in fish community size structure across temperature gradients in correspondence with the dominant thermal fish guild. Lakes located in the warmer European lowlands were dominated by eurythermic cool- and warm-water fish communities with small-sized individuals characterised by linear individual size distributions. Lakes located in cold regions and dominated by stenothermic coldwater salmonids with larger-sized individuals were characterised by unimodal or bimodal size distributions. Our results show that temperature modifies fish community size structure uniformly within the thermal fish guilds and different ecoregions. The importance of temperature in explaining variability in fish size increased when moving from warm to cold regions. After controlling for the natural factors, productivity negatively influenced average fish size. At a macroecological scale, the strong effect of environmental temperature suggests future changes in fish size structure as a consequence of climate change, whereas eutrophication effects become more apparent at a regional scale.
This study was conducted to increase the understanding of the temporal dynamics of the plecopteran-associated endosymbiont species Orphella helicospora and Orphella catalaunica (Harpellales, Zygomycota) in the middle reaches of a stream in Montseny Natural Park (Barcelona, Spain). Previous studies addressing the temporal dynamics of Harpellales have focused on Diptera-related species. Statistical analyses revealed that the temporal dynamics of Plecoptera-associated Harpellales do not respond directly to environmental factors but are more directly dependent on biotic factors, such as the particular preference and fitness of each Orphella species towards a specific Leuctra host, the relative host abundance, and its annual cycle. We report that an in situ host shift linked to Leuctra species replacement occurred during the years 2012 -2013, with a resulting decline of O. catalaunica in this environment. The ecological implications of the specificity range and fitness of the host are discussed. We also provide information about the possible causes of this macroinvertebrate shift and the effects on the associated endozoic community.
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