High Mountain Lakes Research Articles

Shifts in zooplankton communities in high-mountain lakes induced by singular events (fish stocking, earthquakes): evidence from a 20-year survey in Slovenia (Central Europe)

Thirteen mountain lakes, originally fishless, at 1325 and 2150 m a.s.l., with the maximum depths ranging from two to 15 m, and areas of 0.3 to 4.5 ha, were monitored between 1991 and 2012 in the Triglav National Park (Slovenia, Central Europe). The lakes are located on limestone bedrock, with no surface inflow or outflow. They range from ultra-oligotrophic to hypertrophic. They were stocked with fish between late 1920s and 1996. The zooplankton samples were collected as composites from the bottom to the surface at the deepest point of the lake, for both qualitative and quantitative analyses. In situ physical parameters in the water column were measured, and the samples for chemical analyses were collected in parallel with the zooplankton sampling. Thirty-two species, including Copepoda, Cladocera, Rotifera and Ciliata, were recorded. They belonged to three ecological groups: (1) constitutive, (2) scout and (3) benthic species. In some of the lakes, the species composition remained stable over the study period, but in lakes stocked with fish, significant changes occurred, in both species composition and biomass. Large-bodied species of Copepoda and Cladocera were eliminated by fish allowing small-bodied planktonic species of Copepoda, Cladocera and Rotifera to dominate the community, along with benthic species, associated with algal mats. The lake, stocked with fish in the 1920s, was hit by two strong consecutive earthquakes, in 1998 and 2004, after which a significant change in species composition and biomass was recorded.

Construction of Flow Control Structures as an Essential Condition for Increasing the Efficiency of Hydropower Facilities in Mountainous Regions

The hydropower industry of the Kabardino-Balkarian Republic (KBR) is weakened by the absence of flow control structures. Due to the extremely weak flow control of the mountain rivers utilized by hydropower structures, the total production and economic effect of the operating power units is rather low. This circumstance determines the highest seasonal variability of the annual flow — compared to summer months, the capacity of power plants is reduced in winter by almost 5–6 times. It is obvious that it is almost impossible to utilize the entire capacity of river flows. At the same time, it is unacceptable when no more than 20% of the flow capacity is actually used, which leads to extremely low efficiency of expensive power units. The objective of this research is to study the engineering and economical feasibility of controlling the flow of mountain rivers of KBR, to study the possibility of creating an optimal water pressure by constructing water storage facilities, to assess mountain-valley landscapes and select specific cross-sections for the construction of priority flow control facilities. To achieve this objective, the following tasks were solved: - study the conditions of water flow control for glacier-fed mountain rivers; - formulate preliminary flow control schemes within the selected cross-sections; - assess natural properties of watercourses and their relevance for the construction of flow control facilities; search high-mountain lakes suitable for river flow accumulation in the first approximation; - substantiate a suitable sequence of construction of flow control facilities; - assess the approaches to seasonal and long-term water flow rate forecasting as an essential condition for optimizing the operation of hydropower units.

Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake

We investigated modern-littoral and subfossil sediment-core diatoms in the shallow (max depth 6.4 m) high-mountain Lake Balma in the Orsiera Rocciavrè Nature Park (Italian Western Alps). Our study provided evidence that might be related to the response of diatom assemblages to fish introduction, in particular the decreasing of the nutrient-enrichment sensitive low-profile life-form/ecological guild and the increase in species known to react positively to the augmented nutrient availability due to fish excretions (e.g., Fragilaria nanana, Pseudostaurosira brevistriata, Staurosirella neopinnata). We are, however, aware that some of these effects could as well have been caused by pastures and cattle watering, and by increased temperatures due to global warming, and we acknowledge the typical complex-interaction pattern among different stressors. High-mountain lakes are ‘‘early warning systems’’ for the whole alpine system and can contribute valuable information also on the interactions between environmental global changes and anthropogenic impacts. Benthic diatoms, in particular, can provide useful indications on the deleterious effects of non-native fish introduction, cattle grazing, and global warming, and thus support an adaptive and sustainable management of high-mountain lakes for the sake of nature conservation.

Alien fish eradication from high mountain lakes by multiple removal methods: Estimating residual abundance and eradication probability in open populations

Abstract Invasive alien species are among the most important threats to biodiversity. Plans for their eradication have been implemented worldwide but estimating residual population size and eradication probability to assess removal success is complicated by the imperfect detection of residual individuals. Most methods to assess residual abundance and eradication probability rely on the often unrealistic assumption that a population is closed to mortality and recruitment processes during the implementation of removal actions. We extended existing removal models and developed a novel analytical approach to estimate residual population size and derive eradication probability in open populations while accounting for multiple removal methods. We apply this approach to 20 eradication projects in Europe and the United States that used mechanical methods to return high mountain lakes to their original fishless condition. The new removal model incorporates (a) a mechanistic description of the ecological process underlying survival and recruitment probabilities during the eradication period and (b) the use of multiple, concomitant removal methods (i.e. electrofishing, gillnetting, fyke‐netting) at multiple sites simultaneously. We used a subset of ‘control’ lakes where eradication success was confirmed by more than 5 years of post‐removal surveys to validate the model. For these lakes, eradication success, evaluated by whether the 95% Bayesian credible interval for estimated residual population size encompassed values of <2 individuals, was confirmed in 13 out of 15 lake‐by‐species case studies. In addition, the model correctly assigned an eradication probabilities equal to 0 for the eradications that are still in progress. Synthesis and applications. Our study provides insights into the dynamics of fish populations subject to eradication in high mountain lakes of different countries. In addition, the analytical approach proposed accounts for demographic processes and multiple removal methods in multiple sites and seasons. It can represent an informative tool to estimate residual population size and eradication probability of alien species to optimize eradication efforts and efficacy of conservation actions. The extension to open populations makes the approach useful to evaluate long‐term eradication plans.

The unusual isolation of carnobacteria in eyes of healthy salmonids in high-mountain lakes

Carnobacteria are common bacteria in cold and temperate environments; they are also reported during fish mortality events. In a previous study, carnobacteria were isolated from the eyes of healthy wild salmonids from a high-mountain lake. To better understand these findings, salmonids were captured from three high-mountain lakes (Lower and Upper Balma Lake, Rouen Lake; northwest Italy) during August 2019 and subjected to bacteriological and histological examination. Although all were healthy, 8.7% (Lower Balma Lake), 24% (Upper Balma Lake), and 32.6% (Rouen Lake) were positive for carnobacteria colonization of the eyes. A Trojan-horse effect was hypothesized to explain carnobacteria isolation in the eye. This immune-escaping macrophage-mediated mechanism has been identified in other Gram-positive bacteria. Biochemical, molecular, and phylogenetic analysis were carried out on isolated bacteria (Carnobacterium maltaromaticum and C. divergens). Based on previous references for carnobacteria isolated from fish, C. maltaromaticum strains were tested for the pisA precursor gene of the bacteriocin piscicolin 126. Carnobacterium maltaromaticum strains were found to display genotypic heterogeneity and a low percentage of pisA positive amplification. Features of geomorphology, geographic isolation, and microbiota common to the three lakes are thought to be possibly related to our findings. Moreover, terrestrial insects collected from the lake shoreline and the stomach contents were screened for the presence of carnobacteria. The salmonids in these high-mountain environments feed mainly on terrestrial insects, which are considered possible vectors for carnobacteria that might catabolize the exoskeleton chitin. All insects tested negative for carnobacteria, but as a small number of samples were analyzed, their role as possible vectors of infection cannot be excluded. Further studies are needed to corroborate our research hypothesis.

New desmid records from two high mountain lakes in Camlıhemşin/Rize (Turkey)

The benthic algal flora of Avusor Great Lake and Ko?d?z? Great Lake in Rize was investigated on 21 August 2019. A total of 37 desmid taxa belonging to the genera Actinotaenium (2), Closterium (6), Cosmarium (12), Euastrum (4), Micrasterias (3), Penium (1), Staurastrum (8) and Staurodesmus (1) were assessed as new records for Turkey. In this paper, the morphotaxonomy, ecology, and distribution of each species is discussed in detail.

Deployment of ENEX Enclosures in High‐Mountain Lake Redon (Spain)

Photo 1: Ultraoligotrophic Lake Redon (Central Pyrenees Mountains, Spain) with the ENEX experimental enclosures deployed in the central part. Limnological research in this high-mountain lake (2232 m above sea level) has been ongoing for more than 30 years. Photo credit: Pau Giménez-Grau. This photograph illustrates the article “Homeostasis and non-linear shift in the stoichiometry of P-limited planktonic communities” by Pau Giménez-Grau, Marisol Felip Aitziber Zufiaurre, Sergi Pla-Rabès, Lluís Camarero, and Jordi Catalan published in Ecosphere. https://doi.org/10.1002/ecs2.3249.

Исследования арктического гольца Salvelinus alpinus (L.) в Забайкалье: итоги 25-летних работ. Сообщение 1. Распространение, симпатрические формы, морфология, генетика

In Transbaikalia, a much wider than previously believed, though mosaic distribution of Arctic charr has been documented over the last 25 years. We hypothesize that this species migrated to highland headwaters of the Lena drainage from the giant Lena-Vilui paleolake about 200–130 thousand years ago. After that it penetrated from the Lena (Vitim) basin to Lake Baikal basin across the Lena-Baikal watershed in the region of Lake Amut belonging to the Verkhnyaya Angara system. In the glacial epochs Arctic charr dwelled in large valley ice-dammed Vitim, Chara and Olekma lakes, which repeatedly emerged at the territory of Baikal mountain area and during interglacials moved to smaller cold-water high mountain lakes. Transbaikalia is one of the main centers of Arctic charr diversity and intensive speciation. The majority of present-day Transbaikalian populations are polymorphic being represented by two or three sympatric forms differing in adult size. Transbaikalian Arctic charr manifest high morphological interpopulational variability; the main direction of their morphological evolution underpinning their diversification is independent emergence of densely- and long-rakered forms in different lakes as the result of profound specialization to planktophagy. This diversification is also manifested in high-level differences of allopatric and sympatric forms in a number of meristic and morphometric characters. Transbaikalian charr have highly diverse mtDNA control region haplotypes of the Siberian subgroup of the Eurasian phylogenetic group. The data on mtDNA sequence variation evidence close relationship of Transbaikalian charr with Arctic charr of the Siberian subgroup from other parts of East Siberia and confirm their northern origin. The analysis of microsatellite variation shows genetic differentiation of sympatric forms; the level of this differentiation varies among form pairs from different lakes from medium to very high evidencing their reproductive isolation in some of the lakes. In nearly all cases sympatric and parapatric forms are genetically more similar with each other than with the forms from other lakes. The analysis of single nucleotide polymorphisms demonstrates similar results and also shows that parallel emergence of analogous charr forms (ecotypes) in different lakes has different genomic background. Still, as evidenced by transcriptome analysis, it proceeds due to similar changes in gene expression. Monophyletic clustering of Transbaikalian Arctic charr forms in phylogenetic trees according to the lakes and lake systems indicates independent origin of intralacustrine forms in different lakes by sympatric or parapatric speciation, although there are also arguments in favour of their secondary contacts.

Sediment carbon storage increases in tropical, oligotrophic, high mountain lakes

• El Sol and La Luna are valuable sentinels of global change by displaying detectable signs of anthropic disturbances from 1950 onwards. • The higher mass accumulation rates and organic carbon burial rates from 1950 onwards are result of human activities and atmospheric dust deposition. • Sharing the same climatic conditions, climate change unlikely caused the recent higher organic carbon burial observed in both lakes. High mountain lakes are valuable sentinels of global change because they are sensitive to environmental stress and integrate changes in the atmosphere and their catchment areas. This study tested the hypothesis that local and regional anthropogenic stressors have affected productivity, sedimentation, and organic carbon burial in two tropical high mountain lakes in central Mexico. We studied changes in the water column (Secchi disc depth, total suspended solids (TSS), and chlorophyll- a concentrations) and surface sediments (chlorophyll- a and organic carbon concentrations) in El Sol Lake and La Luna Lake during the period 2000–2018, and organic carbon burial rates in sediment cores (∼1884–2014) dated with lead-210 ( 210 Pb). We observed increasing water turbidity, TSS, and organic carbon in surface sediments in El Sol Lake. Different responses of the two lakes were caused by lower pH in La Luna Lake and a threefold residence time of TSS in El Sol Lake compared to La Luna Lake, mostly attributable to their different surface/volume ratios. Organic carbon burial rates were slightly higher at La Luna Lake until 2000, when they became higher at El Sol Lake due to increasing sediment accumulation and organic carbon concentrations. In both lakes, results show significantly higher organic carbon burial rates since the 1950s, likely resulting from the deposition of human-induced wind-blown particles derived from activities at the volcano slopes and long-distance transport from highly urbanized areas. Anthropogenic impacts rather than climate change, therefore, caused the recent higher organic carbon burial rates observed in both lakes. Methods and findings from this study provide a valuable basis for comparing changes in other high mountain lakes worldwide.

First insights into plastic and microplastic occurrence in biotic and abiotic compartments, and snow from a high-mountain lake (Carnic Alps)

Plastic pollution has become a pervasive environmental problem on a global scale, from the ocean depths to the aquatic ecosystems of the Tibetan Plateau. To date, data on plastic and microplastic occurrence in pristine ecosystems like high-mountain lakes are lacking. In this study, plastic (>5000 μm) and microplastic (10–5000 μm) levels were measured in snow at the end of the winter season (April 2020), and in water, sediment, and biological samples collected monthly (June–October 2019) during the ice-free season from the Dimon Lake, a high-mountain lake in the Carnic Alps, northeast Italy. Biological samples consisted of chironomids (Diptera, Chironomidae; n = 150) and stomach contents of Cottus gobio (n = 40). Analysis of the water, sediment, and biological samples revealed the absence of plastic and microplastics larger than 10 μm, whereas the snow samples contained microplastics of polyethylene terephthalate (PET) albeit at very low levels (0.11 ± 0.19 L-1). These results show that while the lake ecosystem could be considered unpolluted by microplastics, abundant snow precipitation in winter can trap microplastic particles that deposit on the ground. The very low levels of PET microparticles recorded in the snow samples suggest the need for further research to better understand the source of microplastic pollution in this environmental matrix.

Liver Lipid Accumulation in European Bullhead (Cottus cobio) from a High-Mountain Lake: An Adaptive Strategy to Survive the Adverse Winter Season

The hypothesis that liver lipid accumulation in fish is an adaptive strategy to survive the winter in the high-altitude environment was assessed in this study. During summer 2019, specimens of Cottus gobio were sampled in 15 watercourses of Friuli Venezia-Giulia Region (Italy) to verify if hepatic steatosis is or not normally present in the species. To do this, hepatic vacuolization was assessed by histology using a semiquantitative score. Furthermore, C. gobio were also captured during the ice-free season at Dimon Lake (1872 m a.s.l.) and But Stream (520 m a.s.l.) to compare the trend in lipid accumulation: water temperature, hepatosomatic index (HSI), gonadosomatic index (GSI), Fulton’s condition factor (K), and lipid area percentage (lipid %) were measured monthly. Findings revealed that liver steatosis is rather common in C. gobio. However, the trend in lipid accumulation of this species differed between Dimon Lake and But Stream. Based on the HSI and the GSI, the reproductive cycles differed in fish from the two environments (April–May in But Stream; May–June in Dimon Lake). While K values remained unchanged in the But Stream specimens, significant changes were recorded for Dimon specimens. The increase in lipid % from July to August in the Dimon Lake specimens coincided with greater food availability. With the rapid drop in lake water temperature in October, the lipid % decreased due to slower metabolic rate and lipid utilization from liver stores. There was a slight decrease in lipid % in the But Stream specimens, indicating that lipids were not being accumulated. Introduced years ago, the Dimon Lake bullhead population has since adapted to the winter conditions at high elevation.

Feeding preferences in aquatic invertebrates associated to Egeria densa in a tropical high-mountain lake

Introduction: The benthic fauna of the littoral zone in lakes is important in transferring energy to other trophic levels, habitat coupling, and helping to keep habitat stability. The study of this type of interactions in lentic systems is priority, since functional aspects about biological communities are unknown. Objective: Describing the trophic relations of aquatic invertebrates of the littoral zone in a tropical high mountain lake by characterizing gut content and stable isotope analysis of δ13C and δ15N. Methods: Samples of benthic invertebrates were collected in the littoral zone of the Lago de Tota where Egeria densa was present using a handheld net method. Samples were processed in the laboratory, organisms were identified, counted and weighed. Gut contents and δ13C and δ15N stable isotopes analysis were performed as well. Results: Records of the trophic relations of aquatic invertebrates, which live in the littoral in high mountain lentic ecosystem in the Neotropics are shown. The analysis of gut contents distinguished seven food items, microphytes and MOPF were the most frequent, and through the stable isotopes analysis (δ15N) we identified four trophic levels, among resources (macrophytes and POM), and consumers (detritivores, herbivores, and predators). The two upper trophic levels concentrated greater diversity and biomass. Conclusion: Most of the organisms studied were linked to omnivorous habits, evidenced in a wide spectrum of food items in their diet. The δ15N values show an enrichment, which occurs due to the effects of the tendency towards eutrophication of the system or due to unknown values of protozoa and bacteria that plays a fundamental role in the diet of these organisms, besides the δ13C values reported in organisms consumes, allows us to suggest an affinity with native resources of the littoral zone.

Conditions of spatiotemporal variability of the thickness of the ice cover on lakes in the Tatra Mountains

This research aimed to identify the impact of local climatic and topographic conditions on the formation and development of the ice cover in high-mountain lakes and the representativeness assessment of periodic point measurements of the ice cover thickness by taking into consideration the role of the avalanches on the icing of the lakes. Field works included measurement of the ice and snow cover thickness of seven lakes situated in the Tatra Mountains (UNESCO biosphere reserve) at the beginning and the end of the 2017/2018 winter season. In addition, morphometric, topographic and daily meteorological data of lakes from local IMGW (Polish Institute of Meteorology and Water Management) stations and satellite images were used. The obtained results enabled us to quantify the impact of the winter eolian snow accumulation on the variation in ice thickness. This variation was ranging from several centimetres up to about 2 meters and had a tendency to increase during the winter season. The thickest ice covers occurred in the most shaded places in the direct vicinity of rock walls. The obtained results confirm a dominating role of the snow cover in the variation of the ice thickness within individual lakes.

Rapid amphibian community recovery following removal of non-native fish from high mountain lakes

Amphibians of high mountain lakes face many threats related to global change, including novel pathogens, development, climate change and overexploitation. However, the foremost threat is the presence of non-native fish. One of the objectives of the LIFE+ LIMNOPIRINEUS project (2014–2019) was the recovery of protected amphibian communities (including the endemic Calotriton asper) in eight naturally fishless Pyrenean high mountain lakes, by controlling or eradicating non-native trout or minnows. During the summer months of 2015 to 2019, we removed 95–100% of the fish present in these lakes, and monitored changes in their amphibian populations, as well as surveyed 56 nearby control lakes with or without fish. We found rapid natural recovery of amphibian communities as fish removal work progressed. The fish-removal lakes achieved typical richness figures for the area one year after fish removal began, and typical species abundances after three years (with the only exception of Rana temporaria). We documented a total of 16 colonisation events, all by amphibian species from the same valley. The two earliest colonisation events were observed in the year in which fish removal began, with eight events the following year. The lack of colonisation from nearby valleys in the study period highlights the crucial role of nearby residual populations not affected by human impacts. We show that whole amphibian communities from high mountain lakes recover rapidly after eliminating or reducing non-native fish, proving that this is a powerful tool to improve the conservation status of endangered amphibians.

Centers of endemism of freshwater protists deviate from pattern of taxon richness on a continental scale

Here, we analyzed patterns of taxon richness and endemism of freshwater protists in Europe. Even though the significance of physicochemical parameters but also of geographic constraints for protist distribution is documented, it remains unclear where regional areas of high protist diversity are located and whether areas of high taxon richness harbor a high proportion of endemics. Further, patterns may be universal for protists or deviate between taxonomic groups. Based on amplicon sequencing campaigns targeting the SSU and ITS region of the rDNA we address these patterns at two different levels of phylogenetic resolution. Our analyses demonstrate that protists have restricted geographical distribution areas. For many taxonomic groups the regions of high taxon richness deviate from those having a high proportion of putative endemics. In particular, the diversity of high mountain lakes as azonal habitats deviated from surrounding lowlands, i.e. many taxa were found exclusively in high mountain lakes and several putatively endemic taxa occurred in mountain regions like the Alps, the Pyrenees or the Massif Central. Beyond that, taxonomic groups showed a pronounced accumulation of putative endemics in distinct regions, e.g. Dinophyceae along the Baltic Sea coastline, and Chrysophyceae in Scandinavia. Many other groups did not have pronounced areas of increased endemism but geographically restricted taxa were found across Europe.

The phylogenetic placement of Temnogametum (Zygnemataceae) and description of Temnogametum iztacalense sp. nov., from a tropical high mountain lake in Mexico

A new species Temnogametum iztacalense sp. nov. (Zygnemataceae) was described using an integrative taxonomic approach. Material was collected between 2014–2019 from purple mats at the bottom of La Luna Lake, which is a shallow, well-oxygenated, acidic and ultraoligotrophic high mountain lake exposed to high levels of ultraviolet radiation. Morphological analysis revealed that the material belonged to the Zygnemataceae and contained mature zygospores of oblate-sphaeroidal shape; smooth and yellow exospores, finely punctate and brown mesospores, and thin hyaline endospores. Transmission electron microscopy showed vacuolization, wavy thylakoids and a large number of starch granules and plastoglobules. The topology of the concatenated 18S-rbcL tree using the Bayesian method separated T. iztacalense into an independent branch within the Zygnematales. The chromatographic profile of T. iztacalense revealed 20 compounds, the major ones being lutein (596.9 ± 20.9 mg g–1 algae) and β-carotene (171.4 ± 3.3 mg g–1 algae). This is the first reported phylogeny of Temnogametum isolated from this kind of lake based on 18S-rbcL sequences.

<p><strong><em>Nupela eremica </em></strong><strong>sp<em>. </em>nov<em>. </em>(Bacillariophyta, Naviculaceae) from a páramo lake in the Colombian Andes</strong></p>

A new species, Nupela eremica sp. nov. is described from a high mountain lake located in the Eastern Range of Colombian Andes. The new taxon was studied from sediment and epiphyton samples and under light and scanning electron microscope. Comparison with morphologically similar taxa is showed. N. giluwensis, N. carolina, N. gomphosphenioides, N. encyonopsis, N. incerta, N. neglecta, N. tenuicephala, and N. exilissima show morphometric values overlapping those of Nupela eremica sp. nov. The combination of valve size and outline is unique and justifies the erection of this new species.

High-Mountain Lakes, Indicators of Global Change: Ecological Characterization and Environmental Pressures

Though mountain lakes are generally much less influenced by human activities than other habitats, global and local anthropogenic threats can alter their natural condition. The most alarming threats are climate change, water exploitation and abstraction, alien species introduction, and the medium-long range atmospheric transport of contaminates. Moreover, tourism and mountain farming are two other major sources of organic pollutants that can pose a threat to local aquatic biodiversity. Papers submitted to this Special Issue should be original contributions, with a focus on ecological and morphological characterization, environmental pressures (i.e., alien species introduction, environmental contaminates), and the use of bioindicators/tracers to inform adequate management plans.

Rhythmic episodes of heating and cooling control thermal stratification of two tropical high mountain lakes

Continuous temperature monitoring for two adjacent tropical crater lakes in Mexico at 4200 m amsl shows that the lakes have rhythmic episodes of heating and cooling with a duration of ~ 30 days during the warmest months. The episodes were caused by rise and decline of solar irradiance reaching the lake surface. One lake, El Sol, showed over each heating and cooling episode a stable mixed layer (~ 20 days) and a deeper layer with a weak thermal gradient. Temperatures below the mixed layer warmed progressively by eddy diffusion after the mixed layer formed. Stratification was followed by full mixing of the water column. Within the same crater, an adjacent second lake, La Luna, showed the same cycles of heating and cooling; it stratified daily but not over multiple days. The difference between the lakes (discontinuous polymictic, continuous polymictic) is explained by the lower transparency of El Sol, which led to greater heat uptake near the surface than the more transparent La Luna. Lower transparency of El Sol was caused by modest anthropogenic effects on total suspended solids and nutrient loading, i.e., small deviations from the natural condition of El Sol caused it to differ qualitatively from La Luna. Events observed in these lakes would not have been evident from weekly temperature records.

Response of the aquatic invertebrate community to the eradication of an exotic invasive fish 30 years after its introduction into an Iberian alpine lake

In Lake Grande de Penalara, an originally fishless small high mountain lake in the Central Iberian Peninsula, brook trout (Salvelinus fontinalis) was introduced in the 1970s, and then eradicated 30 years later using gillnets. In this study, we investigated the time-course and changes in macroinvertebrates and zooplankton communities, before and after the eradication, by studying their richness and several biological and ecological traits of macroinvertebrates. Macroinvertebrates richness increased from 13 taxa coexisting with fish, up to a maximum of 27 taxa after the eradication. Rare groups usually affected by fish predation, e.g. swimmers in surface and open waters, showed high dispersal and recolonization capabilities, while those with burrowing, interstitial or crawler habits maintained their presence, and even with the presence of fish given their advantage of hiding from being directly sighted by fish. Taxa with affinities for rare habitats within the lake (e.g. macrophyte beds) occasionally appeared 4–6 years after eradication. In contrast, zooplankton assemblage did not significantly change in richness in the 10 years after eradication. No new species of cladocerans or copepods appeared after fish removal, but 4 new rotifer taxa appeared and 5 disappeared. This was apparently more related to a change in water quality or trophic status as a consequence of the fish removal than to the direct effect of fish removal on rotifers. Zooplankters were significantly smaller, on average, before fish eradication rather than later, indicating that the community responded to the change in predation pressure.