Saline lakes are hypersensitive to changes in their water balance and therefore show amplified responses to climatic and land-use changes in their catchment. Despite often dramatic ecological impacts, saline lakes rank low on policy agendas as they are assumed to support few ecosystem services and low levels of biodiversity. Here, we challenge this view and evaluate ecosystem services and threatened species in 85 saline lakes distributed across the globe. We show that saline lakes support, additionally to threatened aquatic biota, a diverse range of red-listed terrestrial species that contribute together with a large beta diversity to their conservation value. Further, our results highlight that saline lakes provide a number of culturally and economically important ecosystem services but several of them are 'hidden' and difficult to quantify. We conclude our analysis with best-practice recommendations for sustainable management of saline lakes. Their local adaptation and implementation will be key for safeguarding biodiversity and ecosystem services of these valuable and highly sensitive ecosystems.

Saline lakes are hypersensitive to changes in their water balance and therefore show amplified responses to climatic and land-use changes in their catchment. However, despite the resulting, often dramatic ecological consequences, saline lakes rank low on policy agendas as they are assumed to support few ecosystem services and low levels of biodiversity. Here, we challenge this view and evaluate ecosystem services and threatened species in 84 saline lakes distributed across the globe. We found that saline lakes harbour not only threatened aquatic biota but also a diverse range of red-listed terrestrial species that critically rely on the lakes’ existence. Further, our results highlight that saline lakes support, irrespective of their salinity, a number of culturally and economically important ecosystem services. We conclude our analysis with best-practice recommendations for sustainable management of saline lakes. Their local adaptation and implementation will be key for safeguarding biodiversity and ecosystem services of these valuable but highly sensitive ecosystems.

Addressing complex interactions within water, energy, and food (WEF) resources, innovative tools for in-depth analysis and decision-making are imperative. This study introduces chorematic focus maps (CFMs) as a groundbreaking method to visualize and tackle the WEF nexus’s complexities, focusing specifically on the Danube Delta Biosphere Reserve (DDBR). By merging geospatial analysis with on-site validation, this research reveals intricate interdependencies within the nexus and positions CFMs as an effective tool for stakeholders. This study adopts a methodological approach that focuses on identifying human activities and evaluating their impacts on the WEF nexus, with the goal of developing practical and grounded strategies for managing these essential resources. By testing this approach within the DDBR, the potential for wider application is demonstrated, offering a promising framework for addressing similar socio-environmental challenges across various regions. Future research directions include refining CFMs’ precision and practicality through extended fieldwork and stakeholder engagement, testing the framework’s adaptability across various locations and nexus dynamics. Additionally, incorporating cutting-edge technologies such as machine learning could provide deeper insights and reinforce CFMs’ role in decision support for the WEF nexus. Conclusively, this investigation into the WEF nexus through CFMs emphasizes the critical need for strategies that navigate the complexities of environmental management and resource optimization, marking CFMs as a significant tool for both decision-makers and researchers.

Long-term ecological research of deep Lake Mondsee covers over more than six decades of phytoplankton observation. According to our study, phytoplankton groups of various phenological traits are suitable to address the impact of two major environmental stressors: nutrient surplus by eutrophication from 1968 to 1998 and warming by climate change. Here, we focus on phytoplankton biovolume, phytoplankton assemblage structure, net changes rates, and phytoplankton biodiversity. Biweekly net change-dependent persistence of phytoplankton assemblages followed a dome-shaped relationship of observations. A short-term persistence of taxonomic traits along weeks is predominant and contributes to the structural stabilization of phytoplankton assemblages. This short-term persistence is interpreted by the benefit of lifetime adjustment of phytoplankton organisms. The long-term development phytoplankton structure is discussed as an alignment of organisms over generations. Single key taxa, as Planktothrix rubescens (De Candolle ex Gomont) Anagnostidis &Komárek 1988, which are omnipotent players in phytoplankton assemblages and occur during different environmental scenarios in the long-term, are most suitable for long-term ecological research. Our findings interpret that phytoplankton taxa are excellent organisms to track the impact of environmental constraints due to their short generation time (1), their lifetime adjustment (2), and the re-occurrence in the long-term over generations (3).

The International Association for Danube Research (IAD) was founded in 1956 to promote transboundary exchange in limnology and river management across the ‘Iron Curtain’. This was a necessity to tackle environmental problems, focusing first on pollution. After the political and socio-economic changes in 1989/1990, the IAD concentrated gradually on hydromorphology. As a scientific association that has acted in the Danube Region for decades, IAD could provide scientific input to management authorities, policymakers, and administrations. IAD scientists have contributed to activities of the International Commission for the Protection of the Danube River (ICPDR) and the EU Strategy for the Danube Region (EUSDR), and they were involved in or led transnational projects funded by EU programmes. Scientific progress in lake and river ecology has shaped the IAD’s targets and scientific agenda. Keeping an ecological focus while admitting that ecosystems and humans are inextricably linked determines the future long-term goals of the IAD: conservation and rehabilitation of aquatic ecosystems; integral water protection, and sustainability; raising public awareness; and facilitating cooperation within the Danube River Basin, especially among young researchers.

Macrophytes play an important role in shallow lakes if large standing crop can be achieved. Here we stress the role of submerged macrophytes for benthic-pelagic coupling in the shallow oxbow lake Alte Donau (Austria) during restoration triggered by sufficient light availability (12% surface ambient light, photic >12% depth, zoptimum ) in both, the benthic and the pelagic habitat. Focusing on zoptimum , rather than on minimum light requirement (euphotic depth), seemed to be more meaningful to follow the macrophyte development. After phosphate precipitation treatment, the photic >12% pelagic habitat accounted for more than half of the total water volume in summer, while the achievement of the same photic >12% conditions for half of the total sediment surface area was delayed by 8 years. A delay of light exposure on the lake bottom area compared to the lake water volume is given by the basin morphometry, but the time span that is required for passing this delay depends on the efficiency of restoration measures. The 8-year delay for Alte Donau means that lake restoration focusing on macrophyte re-establishment was difficult to stimulate due to insufficient light exposure at the lake bottom. A further increase of photic >12% conditions to more than 3/4 size of both pelagic and benthic habitat, however, eventually stimulated sustained macrophyte growth. With the onset of this large macrophyte biomass yield, the phosphorus storage pool of submerged macrophytes exceeded the annual peak concentration of total phosphorus of the whole lake water by about one order of magnitude for the first time. Further, the submerged macrophyte bio-surface exceeded the size of lake bottom surface, also by about one order of magnitude. Our results support that macrophytes can act as a significant sink of phosphorus by retaining this nutrient at least during the growing season. We further see the immensely large macrophyte bio-surface as a vast spatial dimension for an additional habitat for freshwater biota. Therefore, we conclude that mature submerged macrophyte formations need to be considered not only as biomass yield, but create a unique macrophyte habitat architecture as a third main component in the network between benthic (lake bottom) and pelagic (lake water) habitat.

Lake Neusiedl, the largest steppe lake in Europe, is particularly sensitive to climate variations due to its extreme shallowness (z(max) = 1.8 m) and low ratio of catchment to lake area (3.5 : 1). Changes in water budget, salinity and turbidity have key implications for the lake's ecology and management. Here, we present a multi-proxy palaeolimnological reconstruction of the evolution of Lake Neusiedl since the end of its last complete desiccation (1865-1868), based on an undisturbed radiometrically dated core taken from the open water portion of the lake. Geochemical and biological (algal) proxies outline the succession of three major ecological stages since 1873 +/- 16 yrs, with the first major changes appearing already in the 1930s as driven by climate related hydrological variability. Subfossil diatoms proved to be reliable for tracking long-term changes in the trophic conditions of Lake Neusiedl while diatominferred lake conductivity revealed to be unreliable due to a combination of lake environmental settings and the absence of a site-specific training set. Nonetheless, multivariate statistical analyses and comparisons with limnological data confirm a great potential of subfossil diatoms for revealing past ecological changes and tipping points of shallow lakes, as long as studies rely on a multi-proxy approach. In agreement with limnological surveys, the sediment record corroborates the high vulnerability of Lake Neusiedl, both in present and past times, towards climate-driven changes in water level and salinity, and allows the prediction, by analogy with the past, of future ecological changes in a context of global warming and increasing nutrient inputs from non-point sources. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of International Association for Great Lakes Research.

The perspective on water transparency changed since the early days of limnology from being a physical parameter of optical water property to an ecological indicator tracking algal turbidity due to eutrophication or an overall success of sustained lake restoration in the late 60ies to 80ies. In modern cities, where ecosystems are commonly deteriorated by man-made modifications, water transparency offers a great opportunity to the public to raise socio-ecological consciousness concerning urban green-blue spaces. We thus re-emphasize water transparency as a key indicator of multi-functional value when assessing an oxbow lake of the riverine floodplain in Vienna, the Alte Donau. Our study covers the eutrophication from 1987 to 1994 due to the inclusion of the riverine landscape in the urban area, the following lake restoration with an ecosystem shift from a nutrient-rich, algal-turbid water body to a nutrient-poor, clear-water macrophyte controlled system and the impact of global warming in recent decades. We used light attenuation profiles to identify depth layers of specific ambient light requirements for photosynthetic domains (phytoplankton and submerged macrophytes), and to interpret Secchi measurements. Here, we calculated the depth at 1% (minimum light requirements for phytoplankton growth as euphotic depth), 3% (minimum light requirements for macrophytes as maximum macrophyte colonization depth), and 12% (preferred light requirements for phytoplankton development) of surface ambient light. A Secchi disk water transparency of 1.5 m (“lake bottom view”), judged as good water quality by human perception, refers to mesotrophic conditions with a maximum colonization depth for macrophytes exceeding the mean lake depth in Alte Donau. Water clarity required for sustained macrophyte growth, in particular for favoring bottom-dwelling Chara meadows instead of tall-growing Myriophyllum spicatum, is 3.5 m Secchi depth and thus exceeds by far water clarity requested due to bathing aesthetics. Global warming, mirrored by an advanced warming in spring seems to favor significantly a higher yield of macrophytes mainly built up by Myriophyllum at the expense of the yield of algae. The prolongation of the summer period above 21°C, however, coincides with lowered Secchi transparency. Water visibility during the hot season thus seems to be slightly hampered against lake restoration efforts by global warming.

Microbial planktonic communities are the basis of food webs in aquatic ecosystems since they contribute substantially to primary production and nutrient recycling. Network analyses of DNA metabarcoding data sets emerged as a powerful tool to untangle the complex ecological relationships among the key players in food webs. In this study, we evaluated co-occurrence networks constructed from time-series metabarcoding data sets (12 months, biweekly sampling) of protistan plankton communities in surface layers (epilimnion) and bottom waters (hypolimnion) of two temperate deep lakes, Lake Mondsee (Austria) and Lake Zurich (Switzerland). Lake Zurich plankton communities were less tightly connected, more fragmented and had a higher susceptibility to a species extinction scenario compared to Lake Mondsee communities. We interpret these results as a lower robustness of Lake Zurich protistan plankton to environmental stressors, especially stressors resulting from climate change. In all networks, the phylum Ciliophora contributed the highest number of nodes, among them several in key positions of the networks. Associations in ciliate-specific subnetworks resembled autecological species-specific traits that indicate adaptions to specific environmental conditions. We demonstrate the strength of co-occurrence network analyses to deepen our understanding of plankton community dynamics in lakes and indicate biotic relationships, which resulted in new hypotheses that may guide future research in climate-stressed ecosystems.

Calcium (Ca) is an essential element for almost all living organisms. Here, we examined global variation and controls of freshwater Ca concentrations, using 440 599 water samples from 43 184 inland water sites in 57 countries. We found that the global median Ca concentration was 4.0 mg L −1 with 20.7% of the water samples showing Ca concentrations ≤ 1.5 mg L −1 , a threshold considered critical for the survival of many Ca-demanding organisms. Spatially, freshwater Ca concentrations were strongly and proportionally linked to carbonate alkalinity, with the highest Ca and carbonate alkalinity in waters with a pH around 8.0 and decreasing in concentrations towards lower pH. However, on a temporal scale, by analyzing decadal trends in >200 water bodies since the 1980s, we observed a frequent decoupling between carbonate alkalinity and Ca concentrations, which we attributed mainly to the influence of anthropogenic acid deposition. As acid deposition has been ameliorated, in many freshwaters carbonate alkalinity concentrations have increased or remained constant, while Ca concentrations have rapidly declined towards or even below pre-industrial conditions as a consequence of recovery from anthropogenic acidification. Thus, a paradoxical outcome of the successful remediation of acid deposition is a globally widespread freshwater Ca concentration decline towards critically low levels for many aquatic organisms.

Benthic invertebrates were used as bioindicators to document the effect of restoration measures in the backwater Alte Donau in Vienna, a former side-arm of the Danube. The study covers four periods of lake management: (1): the mesotrophic year before eutrophication (1987), (2): the 2 years of chemical iron chloride treatment aimed at the phosphate precipitation in the water column and the oxidization of nitrate-treated sediment surface layers (1995-1996), (3): further 3 years of other lake management measures during the restoration period (1995-1999), and (4): an early stage of the re-establishment of underwater vegetation (2000, 2003). Over eight survey years from 1987 to 2003, about 330 benthic invertebrate taxa with three most abundant systematic groups were identified: 37 species of oligochaetes, 23 species of molluscs (18 gastropods and 5 bivalves), and 190 species of the chironomids and other dipterans. The trophic classification index that refers to a habitat quality score by chironomids indicates the year 1987 as mesotrophic (3.46, the index range for mesotrophic conditions is 2.50-3.49). In this year the chironomids and oligochaet species inhabited a variety of diverse habitats ranging from soft sediments (clay and mud), sand, gravel, pebbles and stones to dense stands of macrophytes. The biomonitoring record of 15 mollusc species was significantly higher in this mesotrophic reference year than in any other following survey year. The trophic classification index denotes 1995 as the most eutrophied year. With the restoration and the re-establishment of macrophytes the values of this index decreased but remained higher than during the mesotrophic condition. In the years 1995 and 1996, when the chemical treatment with iron chloride, slaked lime and calcium nitrate was applied and the macrophytes were rare, the biomass of chironomids and oligochaets was particularly low. Among the three important taxonomic groups, i.e. the chironomids, bivalves, and oligochaets, only the first two groups achieved relative biomass dominance. The relative importance of chironomids over oligochaets during these both years of the Riplox-treatment might rather mirror the losses of oligochaets being affected by nitrate exposure than the re-colonization by 'new' chironomid species in the sediment. In addition, in particular active filter feeders such as bivalves seemed to adjust well to the muddy sediment environment after chemical treatment. In the following years of the restoration and the early stage of macrophyte re-establishment, oligochaets and bivalves became the dominant groups mainly contributing to the macrozoobenthic biomass, while the biomass of chironomids remained relatively low. Different from the indication by enhanced water transparency and low phytoplankton biomass achieved by restoration measures in 2004, the shift towards a mesotrophic environment seemed to be retarded when assessing Alte Donau by the chironomid habitat quality score index. The main reason why the chironomid assemblage did not follow the other indicators of mesotrophic conditions in 2004 can be seen in the disruption of the sediment (e. g. by sedimentation of precipitation chemicals) and associated loss of underwater habitat structure due to still relatively low macrophyte biomass during the last invertebrate survey. The phytophilic chironomid species still had a low abundance when only about 50% of the macrophyte biomass was recorded if compared with the mesotrophic situation in 1987. Despite the wax and wane of benthic invertebrates described during the eight-year survey, invertebrate biomass is relatively high in the long-term average and thus characterises Alte Donau as a lowland environment along habitats from low-to high altitudes.

The long-term phytoplankton study in groundwater-seepage lake Alte Donau, a former side-arm of the Danube River in Vienna, covers four main lake treatment periods (1-4) from 1993 to 2014. During hypertrophic conditions with annual total phosphorus (TP) concentrations of 50-70 mu g L-1 and mean summer phytoplankton biovolume of 18-24 mm(3) L-1 before restoration (1), the filamentous cyanobacterium Cylindrospermopsis raciborskii was the main taxon in association with Limnothrix redekei. The drastic phosphorus reduction by chemical RIPLOX-precipitation was repeated twice (2a/b, 1995 and 1996) and resulted in a prompt drop of summer phytoplankton to 4.6 mm(3) L-1 in 1995 and 1.7 mm(3) L-1 in 1996. Non-filamentous cyanobacteria contributed here only moderately while relative high peak contributions of chlorophytes occurred. After years of re-establishment of macrophytes (3), the summer phytoplankton biovolume remained low during the period of sustained ` stable conditions' (4) with values between 0.5 and 1.5 mm(3) L-1. In the long-term, phytoplankton was responding to low annual total phosphorus (10(-1)1 mu g L-1) which finally indicated a mesotrophic state close to oligotrophic conditions according to the lake classification scheme. The long-term median of chlorophyll-a (chl-a) content was 0.50% of wet weight phytoplankton biomass. As the phytoplankton composition shifted from a cyanobacteria dominated assemblage to a phytoplankton assemblage that was composed of taxa of various taxonomic affiliations, the chl-a content varied considerably. Chl-a content reached its lowest median value of 0.19% when cyanobacteria formed blooms contributing 77% to total phytoplankton (period 1) and was highest with 0.83% during the peak development of chlorophytes which contributed 18% to total biovolume (period 2b). The relationship between phytoplankton chl-a and TP is more robust than between phytoplankton biovolume and TP for indicating the lake's trophic state, although both response curves are statistically significant and provide roughly the same main picture of an ecosystem shift from hypertrophic in 1993 to mesotrophic in 2000 and the persistence of mesotrophic conditions for the 15 recent years. Trophic shifts were also indicated by the phytoplankton assemblage metric when comparing phytoplankton species composition between the lake treatment periods. The main picture of seasonal development of phytoplankton taxa and functional phytoplankton groups indicated that assemblages either prevailed in winter to spring or summer to autumn. Annual phytoplankton development thus seems primarily distinctive between the two half-year-cycles, namely the winter-spring and the summer-autumn period, rather than between the four seasons. While the seasonal development of phytoplankton follows the lake phenology commonly observed in temperate lakes, long-term compositional shifts of phytoplankton especially responded to the sustained reduction of TP forced by lake treatment measures in Alte Donau.

Intensively used urban water bodies are vulnerable to eutrophication. The shallow lake Alte Donau (Vienna) can be seen as an example for the extent of anthropogenic influence. Human impacts paired with changes in environmental conditions gave way to eutrophication processes in Alte Donau. Due to the great public interest restoration concepts and subsequently management programs were established. This chapter provides a synthesis of the key aspects to evolve and implement a successful water management plan. An attempt is made to generalise our specific solutions to serve as a basis for the development of similar strategies for other urban lakes.

Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Geneva, Switzerland, 2 Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Ankara, Turkey, Department of Environmental Biology, The University of Adelaide, Adelaide, SA, Australia, Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands, Department of Environmental Sciences, Wageningen University & Research, Wageningen, Netherlands, Center for Limnology, University of Wisconsin-Madison, Madison, WI, United States, 7 Rubenstein Ecosystem Science Laboratory, University of Vermont, Burlington, VT, United States, Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany, 9 Faculty of Mathematics and Natural Sciences, Institute of Biochemistry and Biology, Potsdam University, Potsdam, Germany, Office of Water, US Environmental Protection Agency, Washington, DC, United States, WasserCluster Lunz, Biologische Station GmbH, Lunz am See, Austria, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, United States, Department of Environmental Science and Policy, University of California, Davis, Davis, CA, United States, Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, United States, Department of Limnology and Bio-Oceanography, Faculty of Life Sciences, University of Vienna, Vienna, Austria, Department of Ecology and Genetics/Limnology, Uppsala University, Uppsala, Sweden

Lake restoration is commonly assessed by changes in water transparency, nutrients and biomass of phytoplankton, while information about changes in zooplankton that is triggered by lake management is often missing. In our 19-year study we used rotifers and crustaceans to document the effect of restoration measures on zooplankton in the oxbow lake Alte Donau, a former side-arm of the Danube River which is most popular for recreation and angler (cyprinid-dominated shallow water). The record covers four management periods: the period before restoration, the restoration (including years of chemical phosphate precipitation by Riplox treatment), the re-establishment of macrophytes and the sustained ` stable conditions'. We found the highest abundance of all zooplankton in the first Riplox-year, with decreasing zooplankton abundance in following periods associated with the decline of phytoplankton. In the long term, the main compositional change related to a shift from a cladoceran-rotifer-rich to a copepod-rotifer-rich zooplankton assemblage. Thus, the large-bodied zooplankton shifted from a community composed of mainly filter-feeding herbivorous cladocerans under eutrophic algal-turbid conditions to mainly selective-feeding omnivorous and herbivorous copepods under mesotrophic transparent-water conditions. While the carbon ratio between zoo-and phytoplankton increased significantly during the first three periods and remained high under ` stable conditions', the mean body size of zooplankton did not exhibit a long-term trend. Short-term increases of large-bodied zooplankton coincided with an intermittent increase of calanoid copepod abundance (Eudiaptomus gracilis) during the chemical treatment concomitant with a drastic phytoplankton biomass reduction and the occurrence of large-bodied cladocerans (Simocephalus vetulus and Sida crystallina) in some years with re-established underwater vegetation. Besides the main response of zooplankton to the 'bottom up' control that was triggered by the reduction of phytoplankton food supply by one order of magnitude, we studied the zooplankton response to climate change. The impact of climate warming was evident from intra-annual coincidence of the climate signal (NAODJFM) and water temperature (WT) in winter and early spring, the increase of surface water temperature (SWT) by 1.52 degrees C per decade in April and the prolongation of the warm period (SWT > 22 degrees C) by 10.5 days per decade in summer. This prolongation of the warm season seemed to support the summer development of the medusa stage of freshwater jellyfish (Craspedacusta sowerbii). During the transition from spring to summer, the progressively earlier clear-water phase followed two trends. The first period with a 33-day earlier clear-water phase per decade coincided with pronounced ecosystem changes from a high to a low eutrophic state created by chemical restoration measures. The second period with a moderate earlier progression of 7 days per decade was accompanied by a further, slight TP decrease associated with the re-establishment of macrophytes. When comparing rotifers, cladocerans, calanoid and cyclopoid copepods, the latter group benefits most from seasonal temperature increases and climate warming.

Shallow groundwater seepage lakes are difficult to manage and to restore once they are eutrophied. Effective management and rehabilitation of such lakes need strict and systematic planning based on solid concepts. The model most commonly used for eutrophication is the nutrient loading concept which relies on the limiting nutrient theory. Although not particularly designed for lakes primarily dependent on groundwater, nutrient loading models can be adapted and used to investigate the nutrient input and nutrient balance from the aquifer. These models can also be used to make predictions and to calculate thresholds or limits which must be reached to improve water quality. The theory of alternative stable states provides another excellent concept. Clear water, macrophyte dominated stages can switch to turbid conditions characterized by high algal concentrations. Such forward switches are often associated with anthropogenic pressure or changes in the hydrological regime. Recreational activities often enhance eutrophication processes resulting in a system collapse and an almost spontaneous switch to an alternative state. Backward shift to the original, macrophyte dominated stage can be difficult to attain. Return times are often prolonged due to hysteresis as a result of resilience. Concepts are outlined in general and then specified for the ecosystem in question.

Woolway, R. I., Carrea, L., Merchant, C. J., Dokulil, M., de Eyto, E., DeGasperi, C., Korhonen, J., Marszelewski, W., May, L., Paterson, A., Rimmer, A., Rusak, J., Schladow, G., Schmid, M., Shimaraeva, S., Silow, E., Timofeev, M., Verburg, P., Watanabe, S. and Weyhenmeyer, G. (2017) Lake surface temperature [in “State of the Climate in 2016”]. Bulletin of the American Meteorological Society, 98 (8). pp. 13-14. ISSN 1520-0477 doi: 10.1175/2017BAMSStateoftheClimate.1 Available at http://centaur.reading.ac.uk/72001/

Lesser Flamingo, the flagship species of saline wetlands of Africa and India, is a specialised feeder subsisting on microscopic cyanobacteria and algae. To establish the relationship between flamingo occurrence and food algal abundance and quality, an extensive microphyte survey in more than 150 sampling trips to seven countries over a 15-years period (2001–2015) was carried out. The 44 habitat sites included the core soda lakes in eastern Africa (Bogoria, Nakuru, Elmentaita, Oloidien), where the highest numbers of flamingos were observed, and five breeding sites in eastern and southern Africa as well as in north-western India. A reference describing the diversity of microphytes was established including members of three orders of cyanobacteria and nine orders of eukaryotic algae that potentially could act as food source for Lesser Flamingos. Preferred food organisms consisted of filamentous cyanobacteria, mainly Arthrospira , as well as benthic diatoms. Further investigation on the suitability of other microphytes as alternative flamingo diet revealed the food potential of chlorophytes and euglenophytes. This paper discusses a phycological perspective in the feeding ecology of Lesser Flamingos. The survey findings can assist scientists and conservationists in evaluating the potential of wetlands to support flocks of this endangered bird.