No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Трансформации экосистем пойменных водоемов в условиях современных природных и антропогенных изменений и возможные природоохранные стратегии
Abstract
Обобщается информация об основных негативных факторах, влияющих на состояние пойменных водоемов, описываются самые распространенные последствия абиотических и биотических процессов, предлагаются возможные пути для сохранения пойменных водоемов. Приводятся свидетельства негативного влияния гидростроительства, обвалования пойм, спрямления русел, сельского хозяйства и других антропогенных воздействий. Особую роль играет изменение климата, которое приводит к снижению поемности, высыханию и зарастанию водоемов, их эвтрофированию. Предлагаются критерии для выбора корректных индикаторов, которые могут свидетельствовать о последствиях антропогенных и климатических изменений и о коллапсе таких экосистем. Рекомендовано при оценках состояния пойменных водоемов, рассматривать не отдельные водоемы, а их скопления, и использовать в качестве индикатора изменение β-разнообразия сообществ водных организмов. Дальнейшие природоохранные стратегии могут опираться на подходы Красной книги экосистем Международного союза охраны природы и природных ресурсов, что поможет привлечь внимание к проблеме. Ключевую роль для сохранения пойменных водоемов должны играть территориальные меры охраны, вплоть до разработки отдельной категории для малых водоемов в целом.
ResearchGate has not been able to resolve any citations for this publication.
Water level appears to be crucial for waterbirds, especially in the changeable conditions prevailing in river valleys. One of the best preserved Central European rivers is the Biebrza in north-eastern Poland, which seasonally overflows in spring, creating optimal habitats for various waterbirds. We examined a number of environmental factors which could strongly influence different foraging groups and bird assemblages with respect to water surface area and depth. Number of waterbirds peaked during the second half of March, when a large wave of geese and ducks stopped over there. The species diversity was the greatest in the first half of April, when more species arrived from their wintering grounds. We did not find any relationship between water depth and total abundance, but the former did significantly influence the numbers of some ecological feeding groups of waterbirds, i.e. diving omnivores, diving carnivores and surface carnivores. We assume that higher water level in a river valley is favourable to birds during their spring passage, because it creates areas of shallow floodwater that are intensively used by many different aquatic species. Owing to the well-preserved hydrological conditions and its full protection as a national park, the Biebrza valley not only offers optimal conditions for migratory waterbirds, but is also a good research area for studies of the phenomena taking place in avian communities during their migratory staging.
Extreme climate events and the damming of natural rivers can intensify the effects of droughts and floods, which can consequently affect aquatic biota. We investigated whether a prolonged drought increased the similarity of aquatic metacommunities over time when compared to a period with extreme flood events in 10 floodplain lakes. We expected to find (i) lower temporal environmental variability and lower β diversity among months during the prolonged drought period, and (ii) a more pronounced decrease in β diversity for aquatic organisms with active dispersal (fish) than for small organisms with passive dispersal (phytoplankton and zooplankton) during the prolonged drought period. We estimated the β diversity among months using the Sørensen and Bray–Curtis dissimilarities and their components separately for each lake and each period. We used paired t tests to compare the periods. Although the prolonged drought reduced environmental variability, the homogenization of biota was dependent on the considered β diversity component. In the face of climate change and a higher frequency of severe droughts, biotic variability can decrease over time, thereby changing the dynamics of floodplain ecosystems. We emphasize the importance of natural flood events for maintaining environmental variability and ecosystem functioning in floodplains.
Species distribution and assemblage structuring are influenced by a combination of species dispersal mode and the dispersal routes used. Habitat connectivity is particularly important for passively dispersing taxa such as freshwater molluscs. In addition, current anthropogenic eutrophication affects the structure of assemblages by reducing native fauna and promoting the spread of generalist species. Here, we examined mollusc assemblages in two systems of small lakes differing in hydrological connectivity. The assemblages of 22 isolated lakes in Albania were mainly controlled by the distance between the lakes with a lower contribution of environmental conditions and lake area. In contrast, assemblages of 52 interconnected lakes in Czechia were driven primarily by environmental conditions. However, as lake trophic status increased, the assemblages in Czechia became more homogeneous in species composition as high trophic status filtered out all species except generalists. These assemblages from 33 eutrophic lakes were strongly determined by environmental variables, whereas the remaining assemblages from 19 low trophic lakes were structured by a combination of spatial and environmental variables. We conclude that hydrological connectivity between lakes is crucial for the distribution of molluscs, but eutrophication may influence the importance of individual mechanisms structuring mollusc assemblages.
Dispersal is a main determinant of community assembly. Landscape configurations of rivers, lakes, or ponds are often independently considered in this framework. However, these systems share species conforming to a waterscape with different environments coupled by dispersal. While empirical results support a main role of this coupling on biodiversity organization, it is difficult to assess its importance at large geographic scales. Using a theoretical approach, we quantified the potential role of dispersal through different freshwater ecosystems of the United Kingdom and Ireland on biogeographic diversity patterns. We implemented a coalescent model considering 11,131 communities connected by distance-dependent dispersal and with species that have different performances for recruitment in three different aquatic habitats. Biogeographic diversity patterns were estimated for each habitat alone or for the whole waterscape combining ephemeral, temporal, and permanent waters. The results indicated that the coupling between different types of environments fostered local diversity, in a magnitude that increased from the ephemeral to permanent waters and from poorer to richer communities. Furthermore, a strong spatial structure in the potential effect of dispersal among different freshwater environments was observed, indicating that freshwater biogeography was likely determined by the connection among freshwater ecosystems to a larger extent than previously thought.
As the United Nations develops a post-2020 global biodiversity framework for the Convention on Biological Diversity, attention is focusing on how new goals and targets for ecosystem conservation might serve its vision of ‘living in harmony with nature’1,2. Advancing dual imperatives to conserve biodiversity and sustain ecosystem services requires reliable and resilient generalizations and predictions about ecosystem responses to environmental change and management³. Ecosystems vary in their biota⁴, service provision⁵ and relative exposure to risks⁶, yet there is no globally consistent classification of ecosystems that reflects functional responses to change and management. This hampers progress on developing conservation targets and sustainability goals. Here we present the International Union for Conservation of Nature (IUCN) Global Ecosystem Typology, a conceptually robust, scalable, spatially explicit approach for generalizations and predictions about functions, biota, risks and management remedies across the entire biosphere. The outcome of a major cross-disciplinary collaboration, this novel framework places all of Earth’s ecosystems into a unifying theoretical context to guide the transformation of ecosystem policy and management from global to local scales. This new information infrastructure will support knowledge transfer for ecosystem-specific management and restoration, globally standardized ecosystem risk assessments, natural capital accounting and progress on the post-2020 global biodiversity framework.
Beaver mimicry is a fast-growing conservation technique to restore streams and manage water that is gaining popularity within the natural resource management community because of a wide variety of claimed socio-environmental benefits. Despite a growing number of projects, many questions and concerns about beaver mimicry remain. This study draws on qualitative data from 49 interviews with scientists, practitioners, and landowners, to explore the question of how beaver mimicry projects continue to be promoted and implemented, despite the lack of comprehensive scientific studies and unclear regulatory requirements. Specifically, we investigate how these three groups differentially assess the salience, credibility, and legitimacy of evidence for beaver mimicry and analyze how those assessments affect each group's conclusions about the feasibility, desirability, and scalability of beaver mimicry. By highlighting the interaction between how someone assesses evidence and how they draw conclusions about an emerging natural resource management approach, we draw attention to the roles of experiential evidence and scientific data in debates over beaver mimicry. Our research emphasizes that understanding how different groups perceive salience, credibility, and legitimacy of scientific information is necessary for understanding how they make assessments about conservation and natural resource management strategies.
Progress is being made in assessing the conservation status of ecosystems, notably through initiatives such as the IUCN Red List of Ecosystems (RLE) and the NatureServe Conservation Status Assessment (NCS). Both of these approaches consider conservation status in terms of the risk of ecosystem collapse. However, the scientific understanding of ecosystem collapse is still at a relatively early stage. Consequently, concerns have been raised regarding the scientific basis of ecosystem conservation assessments focusing on collapse risk. Here I explore how these concerns might potentially be addressed by considering how the concept is defined, and by briefly reviewing the theoretical basis of ecosystem collapse. I then examine the implications of recent research results for the design of ecosystem collapse risk assessments, and the challenges identified in those assessments conducted to date. Recommendations are made regarding how collapse risk assessments might be strengthened based on current scientific understanding, and how this understanding could be improved by further research. In addition, I examine the potential implications for conservation policy and practice if the scientific basis of collapse risk assessments is not strengthened in this way.
Changes in the structural characteristics of macrozoobenthos have been studied in six floodplain lakes in the Khoperskiy Nature Reserve in years with different durations of spring flooding. In a dry year, the communities are characterized by a high degree of dominance of some species and low faunistic similarity. The homogenization of the species composition and community structure is observed in subsequent years with prolonged spring flooding.
Ponds are among the most biodiverse and ecologically important freshwater habitats globally and may provide a significant opportunity to mitigate anthropogenic pressures and reverse the decline of aquatic biodiversity. Ponds also provide important contributions to society through the provision of ecosystem services. Despite the ecological and societal importance of ponds, freshwater research, policy, and conservation have historically focused on larger water bodies, with significant gaps remaining in our understanding and conservation of pond ecosystems. In May 2019, pond researchers and practitioners participated in a workshop to tackle several pond ecology, conservation, and management issues. Nine research themes and 30 research questions were identified during and following the workshop to address knowledge gaps around: (1) pond habitat definition; (2) global and long‐term data availability; (3) anthropogenic stressors; (4) aquatic–terrestrial interactions; (5) succession and disturbance; (6) freshwater connectivity; (7) pond monitoring and technological advances; (8) socio‐economic factors; and (9) conservation, management, and policy. Key areas for the future inclusion of ponds in environmental and conservation policy were also discussed. Addressing gaps in our fundamental understanding of pond ecosystems will facilitate more effective research‐led conservation and management of pondscapes, their inclusion in environmental policy, support the sustainability of ecosystem services, and help address many of the global threats driving the decline in freshwater biodiversity.
River-wetland corridors form where a high degree of connectivity between the surface (rheic) and subsurface (hyporheic) components of streamflow creates an interconnected system of channels, wetlands, ponds, and lakes. River-wetland corridors occur where the valley floor is sufficiently wide to accommodate a laterally unconfined river planform that may feature morphologically complex, multi-threaded channels with vegetated bars, islands, and floodplains. River-wetland corridors can develop anywhere there is valley expansion along a drainage network, from the headwaters to estuaries or deltas, and they are found across all latitudes and within all biomes and hydroclimates. River-wetland corridors may be longitudinally continuous but are commonly interspersed with single-thread reaches in narrower portions of the valley. The development and persistence of river-wetland corridors is driven by combinations of geologic, biotic, and geomorphic processes that create a river environment that is diverse, heterogeneous, patchy, and dynamically stable, and within which patterns of flow, sediment features, and habitats shift continually. Hence, we describe these polydimensional river corridors as “kaleidoscope rivers.” Historically, river-wetland corridors were pervasive in wide, alluvial valley reaches, but their presence has been so diminished worldwide (due to a diverse range of anthropogenic activities and impacts) that the general public and even most river managers are unaware of their former pervasiveness. Here, we define river-wetland corridors as a river type; review paleoenvironmental and historical records to establish their past ubiquity; describe the geologic, biotic, and geomorphic processes responsible for their formation and persistence; and provide examples of river-wetland corridor remnants that still survive. We close by highlighting the significance of the diverse river functions supported by river-wetland corridors, the consequences of diminution and neglect of this river type, and the implications for river restoration.
The flood pulse is the main driving force influencing river floodplain ecosystems. The dominant role of the flood pulse on the success of non-native species (NNSs) is what differentiates floodplains from other ecosystems, in terms of invasion. In this review, I discuss some patterns related to the performance of NNSs in response to the flood pulse. First, floods connect floodplain habitats and spread propagules of NNSs, causing ‘propagule pulses’ in these ecosystems. After the establishment of NNSs, floodplains may function as steppingstones for future invasions, because propagule pulses enhance invasions in nearby landscapes. Second, the flood pulse changes environmental filters, with consequences for invasion success and for the coexistence of native and NNSs. Flooding represents a disturbance that enhances the success of some NNSs by reducing biotic resistance and changing resource availability, but diminishes the success of others. Drought enhances the invasion success mainly of NNSs that colonize the aquatic-terrestrial transition zone. Third, impacts caused by river regulation and global changes alter the flood pulse, which in turn affects invasion success. There is a great degree of idiosyncrasy in these patterns, but they pose a broad perspective that helps to understand and manage NNSs in floodplains.
Climatic fluctuations are among the most important factors that cause changes in terrestrial and aquatic ecosystems. This review considers the principal mechanisms of the influence of climate changes on the structure and functioning of ecosystems of water bodies and shows the need to take these mechanisms into account when developing strategies for conserving the biological resources of aquatic ecosystems. Climatic fluctuations affect aquatic ecosystems through changes in temperature, surface runoff of nutrients and other substances and their ratios, the intensity of water mixing during the circulation period, and other mechanisms. Additional nutrients received in rainy periods from the catchment area and directly with precipitation stimulate the growth of primary producers and cause the risk of the further eutrophication of water bodies. An increase in temperature promotes the growth of potentially toxic phytoplankton species and exacerbates the problem of green tides, the massive development of multicellular algae in the coastal zone. Organic substances coming from the catchment area during wet periods stimulate a microbial loop in aquatic ecosystems. In shallow lakes, climate fluctuations can cause changes in food webs and the ecological regime. Climate-induced changes in the composition of producer communities often weaken pelagic-benthic relationships in aquatic ecosystems. In some cases, climate changes have contributed to the invasions of alien species. The natural dynamics of ecosystems affected by climate fluctuations deserves close attention and requires the development of special adaptive management of aquatic biological resources. In some cases, it is necessary to take more severe measures for the protection and restoration of water bodies, which would take into account adverse changes in natural factors.
The aim of this review is to analyze the literature on the impact of beavers on lakes, summarize their effects, describe consequences for biotic and abiotic components, and highlight unresolved issues and perspectives. Beaver activity changes vegetation structure to the greatest extent, indirectly affecting other ecosystem components. Damming of flowing lakes increases the littoral area, which affects diversity and abundance of invertebrates, amphibians, birds, and mammals. Beavers’ alteration of the water regime and heterogeneity and connectivity of habitats has significant effects on zoobenthos, fish, and amphibians. Changes in hydrochemical properties directly affect phytoplankton and benthos. Unlike river ecosystems, where habitats are altered from flowing to still water, in lake ecosystems, habitat type is not usually changed (from lotic to lentic) but their quality (e.g., heterogeneity, connectivity) is. Beaver activity in rivers leads to increased limnophilic biodiversity, but in lakes, it leads to conservation of pre-existing lentic ecosystems. Therefore, impacts of beavers could be of greater importance to limnophilic complexes in lakes than to streams, especially after long time of beaver absence. Digging activity has a more significant role in lakes (especially floodplain) than in rivers. Beaver alteration of heterogeneity and connectivity of habitats is well studied, but not enough is known about impacts on the water regime of seasonally flowing waters, hydrochemical changes (especially eutrophication), amphibian life cycles, phytoplankton and zooplankton communities, parasitocenoses, and coarse woody debris. Methodological difficulties are noted, which are associated with the correct choice of control lakes. Further studies on riverine lakes are crucial. In considerations of climatic changes and anthropogenic impact, beavers may be an additional aid to conserving small lake ecosystems.
Background
The Common Pochard ( Aythya ferina ) (hereafter Pochard), a widespread and common freshwater diving duck in the Palearctic, was reclassified in 2015 from Least Concern to Vulnerable IUCN status based on rapid declines throughout its range. Analysis of its status, distribution and the potential causes for the decline in Europe has been undertaken, but there has never been a review of its status in the major part of its breeding range across Russia to the Pacific coast.
Methods
We reviewed the scientific literature and unpublished reports, and canvassed expert opinion throughout Russia to assess available knowledge about changes in the species distribution and abundance since the 1980s.
Results
While accepting available information may not be representative throughout the entire eastern range of the species, the review found marked declines in Pochard breeding abundance in the last two decades throughout European Russia. Pochard have also declined throughout Siberia. Declines throughout the steppe region seemed related to local drought severity in recent years, necessitating further research to confirm this climate link at larger spatial scales. Declines in the forest and forest-steppe regions appeared related to the major abandonment of fish farms in western Russia that had formerly provided habitat for breeding Pochard. However, hyper-eutrophication of shallow eutrophic lakes, cessation of grazing and haymaking in floodplain systems necessary to maintain suitable nesting habitat and disappearance of colonies of the Black-headed Gull ( Chroicocephalus ridibundus ) in a number of wetlands were also implicated. Increasing invasive alien predator species (e.g. American Mink Neovison vison and Raccoon Dog Nyctereutes procyonoides ) and increasing spring hunting were also thought to contribute to declines. Reports of expansion in numbers and range only came from small numbers occurring in the Russian Far East, including on the border with China and the long-established isolated population on Kamchatka Peninsula.
Conclusions
Widespread declines throughout the eastern breeding range of the Pochard give continued cause for concern. Although we could address all the potential causal factors identified above by management interventions, we urgently need better information relating to key factors affecting site-specific Pochard breeding success and abundance, to be able to implement effective actions to restore the species to more favourable conservation status throughout its breeding range.
Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere¹. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe². Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning. However, existing studies have been unable to identify a consistent continental-scale climatic-change signal in flood discharge observations in Europe³, because of the limited spatial coverage and number of hydrometric stations. Here we demonstrate clear regional patterns of both increases and decreases in observed river flood discharges in the past five decades in Europe, which are manifestations of a changing climate. Our results—arising from the most complete database of European flooding so far—suggest that: increasing autumn and winter rainfall has resulted in increasing floods in northwestern Europe; decreasing precipitation and increasing evaporation have led to decreasing floods in medium and large catchments in southern Europe; and decreasing snow cover and snowmelt, resulting from warmer temperatures, have led to decreasing floods in eastern Europe. Regional flood discharge trends in Europe range from an increase of about 11 per cent per decade to a decrease of 23 per cent. Notwithstanding the spatial and temporal heterogeneity of the observational record, the flood changes identified here are broadly consistent with climate model projections for the next century4,5, suggesting that climate-driven changes are already happening and supporting calls for the consideration of climate change in flood risk management.
The structure of spawning taxocenoses of anuranamphibians in five floodplain lakes of the Medveditsa river valley in 2009–2018 is analysed. Two near-terrace lakes (Lebyazhye and Koblovo) and three lakes of the central floodplain (Sadok, Kruglen’koye, and Cherepashie) were used as model ones. The degradation of the populations of the three most numerous species, a decrease in the dominance degree of the common spadefoot toad were established. Degradation is more characteristic of species with a longerer distance ofspawning migrations – the severity of changes consistently decreases in the row of species: Pelophylax ridibundus → Pelobates fuscus → Bombina bombina. Indices of the structure of amphibian communities in the near-terrace lakes Lebyazhye and Koblovo were stable. Against the background of low water content and unstable hydrological regime of the central floodplain lakes witha survey duration of five or more years, three periods were established to characterize the structure of spawning amphibian taxocenoses, namely: a stable structure, a sharp decrease in dominance and an increase in evenness, and an increase in the variability of the main attributes of the structure. At the end of the third period, which characterizes the structure of taxocenoses, some stabilization of the main parameters was noted with an extremely low number of mature individuals of all amphibian species. The high level of spring flood of the Medveditsa river in 2018 determined the beginning of the exit from the abnormally long period of low water content of the spawning lakes in the floodplain (from 2009 till 2017) and their functioning in the hydrological regime as temporary water bodies. The sudden increase in water content of the floodplain lakes and the extension of their hydroperiod allow the beginning of the recovery process of the population size and community structure of anuran amphibians to be noted.
The present study is devoted to the study of species diversity and spatial distribution of the structural parameters of zooplankton community in the lake-oxbow Inorki in 2014 and 2016. The lake is in the middle right-bank floodplain of the River Moksha. The area of the lake is 0.209 km2, the maximum length is about 3.7 km, the average width is about 95 m and the depth is 3.5–5.5 m. The riparian part of the lake is steep. And at a distance of 1–2 m from the shore the depths reach 1.5 m in most places. Zooplankton samples were taken on three stems (one in the centre, at a depth of >200 cm, and each shore, at a depth of 80 cm) in three sections from the boats early July 2014 (water temperature: 24–27ºC) and 2016 (water temperature: 21.5–22ºC) and treated by conventional methods. By compiling the list of zooplankton species, in Lake Inorki we have obtained the data of the three samples in June 2009 (54.7265º N; 43.1523º Е) and five samples early July 2013. We have detected 93 species and forms of zooplankton. There are rotifer species of the Middle Volga region: Asplanchnopus multiceps, Euchlanis proxima, Squatinella mutica, S. rostrum, S. tridentatа, Trichocerca weberi which prefer the overgrown and waterlogged water bodies. 11 species in Lake Inorki have been registered in all years of study: Asplanchna priodonta, Conochilus hippocrepis, Keratella cochlearis, Lecane closterocerca, Mytilina ventralis, Synchaeta pectinata, Testudinella patina, Chydorus sphaericus, Graptoleberis testudinaria, Sida crystallina, Mesocyclops leuckarti. The average abundance of zooplankton is significantly higher in the pelagic part of the lake than in its coastal zone (t = 8.82–11.38, at p < 0.05). The taxonomic structure of zooplankton community showed differences. So, in 2014 rotifers dominated, while in 2016 the abundance of nauplial stages copepod was the highest. Perhaps, at the time of sampling in 2016, the zooplankton community was at the earlier stage of seasonal dynamics due to low water temperature. This year there was a smaller number of dominant species and a high spatial homogeneity. The ratio of ecological zooplankton groups was different through the years and parts of sampling. In 2014 verticators mainly dominated. Moreover, their percentage was the highest (78%) in the open part of the lake. In 2016 apart from filter-feeders, the zooplankton community was presented by a high proportion of grabbers, nauplii and Copepods larvae: their proportions were 65% and 50% near the lake shores and 44% in the centre of the lake. The state of Lake Inorki has been estimated as mesotrophic according to the Shannon index and the trophy coefficient.
Shallow lakes are strongly affected by global climate changes, reflected in significant parameters of ecosystem deterioration i.e. biodiversity decrease, and water turbidity. During the summer in 2012 and 2013 we conducted zooplankton research in the Škrčev kut oxbow lake (Krapina River watershed, NW Croatia, Europe) with the aim to determine the effect of inter-annual, short-timescale changes of hydrological regime on environmental conditions, macrophytes, zooplankton and fish assemblage within an oxbow lake in the temperate region. Within one-year period water level increased for 2 meters. This caused significant reduction of floating-leaved macrophytes (i.e. Nuphar lutea), while turbidity, ortho-phosphate and chlorophyll a concentrations increased. These altered ecological conditions were reflected in shift from floating-leaved macrophytes at lower water level to phytoplankton dominated lake at higher water level. Zooplankton underwent significant alteration in assemblage. Results suggest that fish preference suppressed cladocerans and enhanced rotifers and copepods abundance. Our results indicate that even in a short-timescale zooplankton assemblage mediates in modification of ecosystem functioning.
The IUCN Red List of Ecosystems is a global framework for monitoring the status of ecosystems. It is part of the growing toolbox for assessing risks to biodiversity and aims to support conservation, resource use, and management decisions by identifying ecosystems most at risk of biodiversity loss. By targeting a level of biological organisation above species, the IUCN Red List of Ecosystems complements The IUCN Red List of Threatened Species™. The IUCN Red List of Ecosystems Categories and Criteria are designed to be: widely applicable across ecosystem types and geographical areas; transparent and scientifically rigorous; and easily understood by policy makers and the public.
The IUCN Red List of Ecosystems Categories and Criteria
The basis of the IUCN Red List of Ecosystems is the IUCN Red List of Ecosystems Categories and Criteria, a set of eight categories and five criteria that provide a consistent method for assessing the risk of ecosystem collapse. The eight categories of ecosystem risk are: Collapsed (CO), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD), and Not Evaluated (NE).
The IUCN Red List of Ecosystems protocol comprises five rule-based criteria (A-E) for assigning ecosystems to a risk category. Two of these criteria assess spatial symptoms of ecosystem collapse: declining distribution (A) and restricted distribution (B). Two criteria assess functional symptoms of ecosystem collapse: environmental degradation (C) and disruption of biotic processes and interactions (D). Multiple threats and symptoms can be integrated in a model of ecosystem dynamics to produce quantitative estimates of the risk of collapse (E). The Guidelines include comprehensive sections to support application of each of the five criteria, including information on relevant theory, thresholds and examples.
Application and documentation standards
The Guidelines assist correct implementation of the IUCN Red List of Ecosystems Categories and Criteria by providing information on the development of the protocol and a detailed overview of the scientific foundations supporting the categories and criteria. They define assessment units (ecosystem types); define ecosystem collapse; discuss the influence of scale; and explain the structure of the risk assessment protocol. The Guidelines also provide detailed definitions of the terms used in the IUCN Red List of Ecosystems Categories and Criteria.
The Guidelines aim to support the practical implementation of the IUCN Red List of Ecosystems Categories and Criteria from subnational to global areas of assessment. The Guidelines therefore outline the necessary steps to: define the assessment area; define the unit under assessment; apply the criteria; and prepare the assessment documentation for peer review and publication. All the steps are illustrated with examples spanning a wide range of ecosystem types, geographical localities and levels of data availability.
The future of the IUCN Red List of Ecosystems
The IUCN Red List of Ecosystems programme will assess the global status of the world’s terrestrial, marine, freshwater and subterranean ecosystems. In addition, the programme aims to support the development of national and regional Red Lists to inform conservation planning and sustainable development. For more information on the IUCN Red List of Ecosystems please consult the IUCN Red List of Ecosystems website (www.iucnrle.org).
The population of the Russian desman in all historical areas is currently no more than 8000–10,000 individuals. The estimated population size of the Russian desman is based on direct surveys during 2010–2016. We observed over 266 km of the coastline in eight regions where the desman lives. Since the early 20th century the number of specimens has been steadily declining. In addition to the previously described factors that determine the reduction of the population size, such as land reclamation, the construction of hydroelectric stations and the flourishing of poaching at the end of the last century, the status of the Russian desman population is adversely affected by periodic droughts and the absence of floods. Currently Protected Areas remain as the only passive measure to protect the Russian desman in the absence of a programme to species protection nor state support.
Nature-based Solutions (NbS) are defined by IUCN as actions to protect, sustainably manage and restore natural or modified ecosystems, which address societal challenges (e.g. climate change, food and water security or natural disasters) effectively and adaptively, while simultaneously providing human well-being and biodiversity benefits. The NbS concept, as used in environmental sciences and nature conservation contexts, has emerged within the last decade or so, as international organisations search for ways to work with ecosystems – rather than relying on conventional engineering solutions (such as seawalls) – to adapt to and mitigate climate change effects, while improving sustainable livelihoods and protecting natural ecosystems and biodiversity.
NbS is a relatively ‘young’ concept, still in the process of being framed. There is a need now to deepen our understanding of NbS and confirm the principles upon which NbS is based, in order to move towards an operational framework that can guide applications of the NbS concept. The following set of NbS principles are proposed.
Nature-based Solutions:
1. embrace nature conservation norms (and principles);
2. can be implemented alone or in an integrated manner with other solutions to societal challenges (e.g. technological and engineering solutions);
3. are determined by site-specific natural and cultural contexts that include traditional, local and scientific knowledge;
4. produce societal benefits in a fair and equitable way, in a manner that promotes transparency and broad participation;
5. maintain biological and cultural diversity and the ability of ecosystems to evolve over time;
6. are applied at the scale at a landscape;
7. recognise and address the trade-offs between the production of a few immediate economic benefits for development, and future options for the production of the full range of ecosystems services;
8. are an integral part of the overall design of policies, and measures or actions, to address a specific challenge.
NbS is best considered an umbrella concept that covers a range of different approaches. These approaches have emerged from a variety of spheres (some from the scientific research domain, others from practice or policy contexts) but share a common focus on ecosystem services and aim to address societal challenges. These NbS approaches can be classified into: (i) ecosystem restoration approaches (e.g. ecological restoration, ecological engineering and forest landscape restoration); (ii) issue-specific ecosystem-related approaches (e.g. ecosystem-based adaptation, ecosystem-based mitigation, and eco-system-based disaster risk reduction); (iii) infrastructure-related approaches (e.g. natural infrastructure and green infrastructure approaches); (iv) ecosystem-based management approaches (e.g. integrated coastal zone management and integrated water resources management); and (v) ecosystem protection approaches (e.g. area-based conservation approaches including protected area management).
A lack of operational clarity presents a major obstacle to the credibility and applicability of new concepts in the fields of conservation and development. Several parallel exercises are currently underway to develop operational parameters for specific NbS approaches (such as Ecosystem-based Adaptation and REDD+), each proposing its own set of criteria. Many of these criteria could be relevant for other approaches within the NbS ‘family’ and there is likely an overarching set of parameters, or ‘standards’, that can guide implementation of all types of NbS interventions. To help in this endeavour, five preliminary parameters are proposed: ecological complexity, long-term stability, scale of ecological organisation, direct societal benefits and adaptive governance. By unifying NbS approaches under a single operational framework, it becomes possible to scale up their implementation and strengthen their impact in mitigating the world’s most pressing challenges.
We monitored the abundance of eight breeding wader species in the Vinogradovo Floodplain during 2002–2014 and compare our results with data from 1982– 1983 and 1995–1996. We describe the trends in agricultural land use in the region, as well as trends in the intensity of spring flooding, and relate these to fluctuations in the abundance of waders. The level and duration of spring floods is an important natural factor which can interact with changing land use and farming practices. We suggest that a strong reduction in the intensity of farming activities (up to full termination of grazing and ploughing) and a decrease in the intensity of floods at the end of the 20th century are the main factors influencing the abundance of waders. As a result of these changes, we observed catastrophic declines in the numbers of Ruff Philomachus pugnax and Terek Sandpipers Xenus cinereus, and strong declines in the abundance of Northern Lapwings Vanellus vanellus and Black-tailed Godwits Limosa limosa. We observed variable numbers of Great Snipes Gallinago media and Marsh Sandpipers Tringa stagnatilis during 2002–2014, but no strong trends, and observed a slight increase in the abundance of Common Snipes G. gallinago. We discuss the reasons for changes in numbers of each species, in relation to environmental and land use change.
Due to their origin and their morphometric and hydrodynamic parameters, oxbow lakes represent a distinct type of aquatic ecosystem, especially compared with post-glacial lakes. The functioning of oxbows is directly and indirectly connected with temporal fluctuations of the water level in rivers. Periodic inundation of floodplain habitats provides primary producers with access to mineral and organic compounds, creates refuge conditions for aquatic organisms against disturbances in the river channel, and contributes to the increase of biodiversity in the whole river system. To determine the best predictors of zooplankton community indices, as well as those of rotifer and crustacean species, we examined them with respect to the
following environmental parameters: the type of habitat, the type of land uses, the shading of the lake’s surface and the presence of fish. The study was performed on oxbows during limnophase. Despite the fact that the biotic structure in oxbows may be simplified, it was found that a high level of habitat complexity positively influences zooplankton species richness and the Shannon-Weaver index of diversity. This would support the fact that during limnophase, oxbows are in an ecotonal phase – between the flooding and the stabilization period. In contrast to other types of small water bodies, the type of land uses (forest vs. field) that affected the quality of the supplies of organic and mineral compounds, along with the presence of fish, did not have a pronounced effect on either zooplankton diversity or their community abundance. Particular zooplankton species also exhibited habitat segregation in accordance with their ecological group (pelagic vs. littoral species) or taxonomic affiliation (rotifers vs. crustaceans). Littoral species, attributed to elodeids, preferred oxbows with a high degree of overshading. Among the pelagic zooplankton, which preferred to remain in the open water zone, a large representation of eutrophic species was recorded due to the overload of the water by mineral nutrients and organic matter. The high zooplankton diversity of the studied aquatic ecosystems and the abiotic features, which revealed an unstable and disturbed status, confirmed the fact that
oxbows during the limnophase reflect an ecotonal phase. This may be a complementation to the river flood pulse concept.
We evaluated the influence of habitat connectivity and local environmental factors on the distribution and abundance of functional fish groups in 10 floodplain lakes in the Biebrza River, northeastern Poland. Fish were sampled by electrofishing, and 15 physico-chemical parameters were recorded at three sampling sites at each lake in the period of 2011-2013. A total of 18,399 specimens, belonging to 23 species and six families, were captured. The relationships between environmental factors and fish communities were explored with the use of canonical correspondence analysis (CCA). Sampling sites were grouped based on fish communities using a hierarchical cluster analysis (HCA). Along a lateral connectivity gradient from lotic to lentic habitats (parapotamic-plesiopotamic-paleopotamic), the proportions of rheophilic species were determined as 10:5:1, whereas the proportion of limnophilic species was determined as 1:2:5. The predominant species were the roach (Rutilus rutilus), and pike (Esox lucius) in parapotamic lakes, rudd (Scardinius erythropthalmus) and pike in plesiopotamic lakes, and sunbleak (Leucaspius delineates) and Prussian carp (Carassius auratus gibelio) in paleopotamic lakes. The findings indicated that the composition and abundance of fish communities are determined by lake isolation gradient, physico-chemical parameters and water stage. Although intact riverine ecosystems may promote fish biodiversity, our findings suggest that lateral connectivity between the main channel and floodplain lakes is of utmost importance. Thus, the conservation of fish biodiversity requires the preservation of this connectivity.
Abstract
JUNK, W. J., P. B. BAYLEY, AND R. E. SPARKS, 1989. The flood pulse concept in river-floodplain
systems, p. 110-127. In D. P. Dodge [ed.] Proceedings of the International Large River
Symposium. Can. Spec. Publ. Fish. Aquat. Sci. 106.
The principal driving force responsible for the existence, productivity, and interactions of the major biota in river—floodplain systems is the flood pulse. A spectrum of geomorphological and hydrological conditions produces flood pulses, which range from unpredictable to predictable and from short to long duration. Short and generally unpredictable pulses occur in low-order streams or heavily modified systems with floodplains that have been leveed and drained by man. Because low-order stream pulses are brief and unpredictable, organisms have limited adaptations for directly utilizing the aquatic/terrestrial transition zone (ATTZ), although aquatic organisms benefit indirectly from transport of resources into the lotic
environment. Conversely, a predictable pulse of long duration engenders organismic • adaptations and strategies that efficiently utilize attributes of the ATTZ. This pulse is coupled with a dynamic edge effect, which extends a "moving littoral" throughout the ATTZ. The moving littoral prevents prolonged stagnation and allows rapid recycling of organic matter and nutrients, thereby resulting in high productivity. Primary production associated with the ATTZ is much higher than that of permanent water bodies in unmodified systems. Fish yields and production are strongly related to the extent of accessible floodplain, whereas the main river is used as a migration route by most of the fishes. In temperate regions, light and/or temperature variations may modify the effects of the pulse, and anthropogenic influences on the flood pulse or floodplain frequently limit production. A local floodplain,
however, can develop by sedimentation in a river stretch modified by a low head dam. Borders of slowly flowing rivers turn into floodplain habitats, becoming separated from the main channel by levées. The flood pulse is a "batch" process and is distinct from concepts that emphasize the continuous processes in flowing water environments, such as the river continuum concept. Flooclplains are distinct because they do not depend on upstream processing inefficiencies of organic matter, although their nutrient pool is influenced by periodic lateral exchange of water and sediments with the main channel. The pulse
concept is distinct because the position of a floodplain within the river network is not a primary determinant of the processes that occur. The pulse concept requires an approach other than the traditional limnological paradigms used in lotic or lentic systems.
Résumé
JUNK, W. J., P. B. BAYLEY, AND R. E. SPARKS. 1989. The flood pulse concept in river-floodplain
systems, p. 110-127. In D. P. Dodge [cd.] Proceedings of the International Large River
Symposium. Can. Spec. Publ. Fish. Aquat. Sci . 106.
Les inondations occasionnées par la crue des eaux dans les systèmes cours d'eau-plaines inondables constituent le principal facteur qui détermine la nature et la productivité du biote dominant de même que les interactions existant entre les organismes biotiques et entre ceux-ci et leur environnement. Ces crues passagères, dont la durée et la prévisibilité sont variables, sont produites par un ensemble de facteurs géomorphologiques et hydrologiques. Les crues de courte durée, généralement imprévisibles, surviennent dans les réseaux hydrographiques peu ramifiées ou dans les réseaux qui ont connu des transformations
importantes suite à l'endiguement et au drainage des plaines inondables par l'homme. Comme les crues survenant dans les réseaux hydrographiques d'ordre inférieur sont brèves et imprévisibles, les adaptations des organismes vivants sont limitées en ce qui a trait à l'exploitation des ressources de la zone de transition existant entre le milieu aquatique et le milieu terrestre (ATTZ), bien que les organismes aquatiques profitent indirectement des éléments transportés dans le milieu lotique. Inversement, une crue prévisible de longue durée favorise le développement d'adaptations et de stratégies qui permettent aux organismes d'exploiter efficacement 1 'ATTZ. Une telle crue s'accompagne d'un effet de bordure dynamique qui fait en sorte que l'ATTZ devient un « littoral mobile'<. Dans ces circonstances, il n'y a pas de stagnation prolongée et le recyclage de la matière organique et des substances nutritives se fait rapidement, ce qui donne lieu à une productivité élevée. La production primaire dans l'ATTZ est beaucoup plus élevée que celle des masses d'eau permanentes dans les réseaux hydrographiques non modifiés. Le rendement et la production de poissons sont étroitement reliés à l'étendue de la plaine inondable, tandis que le cours normal de la rivière est utilisé comme voie de migration par la plupart des poissons.
A review of the Green Data Books in different regions of Russia and Ukraine are presented. The optimized system of criteria for the identification and estimation of rare communities by the example of the Green Data Book of the Republic of Bashkortostan are proposed. The possibilities of application of the criteria for the estimation of plant communities of forest and meadow vegetation of the South Ural region are shown.
In response to growing demand for ecosystem-level risk assessment in biodiversity conservation, and rapid proliferation of locally tailored protocols, the IUCN recently endorsed new Red List criteria as a global standard for ecosystem risk assessment. Four qualities were sought in the design of the IUCN criteria: generality; precision; realism; and simplicity. Drawing from extensive global consultation, we explore trade-offs among these qualities when dealing with key challenges, including ecosystem classification, measuring ecosystem dynamics, degradation and collapse, and setting decision thresholds to delimit ordinal categories of threat. Experience from countries with national lists of threatened ecosystems demonstrates well-balanced trade-offs in current and potential applications of Red Lists of Ecosystems in legislation, policy, environmental management and education. The IUCN Red List of Ecosystems should be judged by whether it achieves conservation ends and improves natural resource management, whether its limitations are outweighed by its benefits, and whether it performs better than alternative methods. Future development of the Red List of Ecosystems will benefit from the history of the Red List of Threatened Species which was trialled and adjusted iteratively over 50 years from rudimentary beginnings. We anticipate the Red List of Ecosystems will promote policy focus on conservation outcomes in situ across whole landscapes and seascapes.This article is protected by copyright. All rights reserved
Floodplain lakes are important elements of landscapes with big rivers. In this study we compared planktonic communities of two oxbow lakes of the Vistula River. We investigated how the inflow of the river's water affected their physicochemical and biological conditions including water temperature, water transparency, oxygen concentration, and macrophyte coverage of the bottom. These parameters in turn affected plankton community. The average phytoplankton abundance in the isolated lake was over two times lower than in the lake connected to the river. Cryptophyta dominated in the phytoplankton community in the isolated lake and diatoms – in the lake supplied with water from the river. The average abundance of zooplankton in the isolated lake was more than twice as high as that in the lake which was connected to the river. The first lake proved to be more attractive for zooplankton due to its stable living conditions (similar to the conditions observed in ponds), higher temperature in summer, and nutrient availability due to the high abundance of small phytoplankton. The results of our research indicate that species composition, plankton abundance, and Chl-a concentration depended on whether there was water exchange between the particular lake and the Vistula River. Hydrological conditions shaped the relationships between the components of the biota.
Disturbance can strongly influence ecosystems, yet much remains unknown about the relative importance of key processes (selection, drift, and dispersal) in the recovery of ecological communities following disturbance. We combined field surveys with a field experiment to elucidate mechanisms governing the recovery of aquatic macroinvertebrates in habitats of an alluvial floodplain following flood disturbance. We monitored macroinvertebrates in 24 natural parafluvial habitats over 60 days after a major flood, as well as the colonization of 24 newly-built ponds by macroinvertebrates over 45 days in the same floodplain. We examined the sources of environmental variation and their relative effects on aquatic assemblages using a combination of null models and Mantel tests. We also used a joint species distribution model to investigate the importance of primary metacommunity structuring processes during recovery: selection, dispersal, and drift. Contrary to expectations, we found that beta diversity actually decreased among natural habitats over time after the flood or the creation of the ponds, instead of increasing. This result was despite environmental predictors showing contrasting patterns for explaining community variation over time in the natural habitats compared with the experimental ponds. Flood heterogeneity across the floodplain and spatial scale differences between the experimental ponds and the natural habitats seemingly constrained the balance between deterministic and stochastic processes driving the ecological convergence of assemblages over time. While environmental selection was the dominant structuring process in both groups, biotic interactions also had a prominent influence on community assembly. These findings have profound implications towards understanding metacommunity structuring in riverscapes that includes common linkages between disturbance heterogeneity, spatial scale properties, and community composition.
Anthropogenic disturbances have become one of the primary causes of biodiversity decline in freshwater ecosystems. Beyond the well-documented loss of taxon richness in increasingly impacted ecosystems, our knowledge on how different facets of α and β diversity respond to human disturbances is still limited. Here, we examined the responses of taxonomic (TD), functional (FD) and phylogenetic (PD) α and β diversity of macroinvertebrate communities to human impact across 33 floodplain lakes surrounding the Yangtze River. We found that most pairwise correlations between TD and FD/PD were low and non-significant, whereas FD and PD metrics were instead positively and significantly correlated. All facets of α diversity decreased from weakly to strongly impacted lakes owing to the removal of sensitive species harboring unique evolutionary legacies and phenotypes. By contrast, the three facets of β diversity responded inconsistently to anthropogenic disturbance: while FDβ and PDβ showed significant impairment in moderately and strongly impacted lakes as a result of spatial homogenization, TDβ was lowest in weakly impacted lakes. The multiple facets of diversity also responded differently to the underlying environmental gradients, re-emphasizing that taxonomic, functional and phylogenetic diversities provide complementary information on community dynamics. However, the explanatory power of our machine learning and constrained ordination models was relatively low and suggests that unmeasured environmental features and stochastic processes may strongly contribute to macroinvertebrate communities in floodplain lakes suffering from variable levels of anthropogenic degradation. We finally suggested guidelines for effective conservation and restoration targets aimed at achieving healthier aquatic biotas in a context of increasing human impact across the ‘lakescape’ surrounding the Yangtze River, the most important being the control of nutrient inputs and increased spatial spillover effects to promote natural metasystem dynamics.
Water levelsWater levels often change in wetlands, particularly in wetlands along rivers or on the shorelines of lakes. These flood pulsesFlood pulses are natural and many of the plants and animals in wetlands depend upon them. In general, high-water periods drown terrestrial plants, creating habitat for wetland species. They also allow fishFish to forage more widely in floodplainsFloodplains and amphibiansAmphibians to reproduce. Low-water periods allow wetland plants to reproduce from seedsSeeds, and create mud flats on which migratory birdsBirds feed. Water levels change over an annual cycle, but they also change over longer cycles of a decade or longer. The twin limit modelTwin limit model shows how these long-term changes in water levels affect wetlands and entire watersheds.
This study shows how beaver digging activity can affect water body morphology and local biota under modern environmental conditions in a small floodplain lake. The total area of microhabitats created by beavers was found to reach 7% of water body area and 30% of littoral-zone area. It was noted that the zoogenic microhabitats are different when depth is greater and plant cover is smaller, especially of emergent vegetation. Helophytes Sparganium erectum and Alopecurus aequalis were found to prefer the beaver-unaffected part of the littoral. Invertebrates Naucoris sp. and Hydrophilus sp. prefer beaver microhabitats, whereas Planorbis planorbis, Lymnaea palustris, and Hydrous sp. prefer thickets of emergent plants in beaver-unaffected littoral areas. Adult crucian carps Carassius carassius proved to be abundant in the beaver-unaffected part of the water body, while the adult weatherfish Misgurnus fossilis prefers beaver burrows, and its fry inhabit beaver-unaffected sites. A similar situation was observed for marsh frogs Pelophylax ridibundus: adults prefer beaver microhabitats in June, but frog tadpoles mainly inhabit a beaver-unaffected littoral. Tadpoles of Pelobates vespertinus proved to be slightly aggregated near beaver burrows in July. The beaver activity was found to slightly increase β-diversity within the water body according to Jaccard indices. The results confirm that the beaver-created heterogeneity is important for aquatic biota under conditions of shallowing of floodplain water bodies.
Lateral hydrological connectivity (LHC) is a key process in maintaining aquatic biodiversity in river floodplain ecosystems. However, the effects of LHC loss on aquatic biodiversity are rarely studied. Here, we evaluated, for the first time, the responses of multiple facets (i.e., taxonomic, functional and phylogenetic) of alpha and beta diversity of freshwater molluscs to the LHC loss in 23 floodplain lakes in the Yangtze River Basin in China. Our results showed that taxonomic and functional alpha diversities were all significantly higher in connected lakes (CLs) than in disconnected lakes (DLs), whereas phylogenetic alpha diversity (Δ⁺) was lower in CLs than in DLs. For beta diversity facets, taxonomic (Tβsor) and phylogenetic (Pβsor) dissimilarities were slightly more contributed by the turnover component or equally contributed by the turnover and nestedness-resultant components both in CLs and DLs. Instead, functional beta diversity (Fβsor), generally showing much lower values than Tβsor and Pβsor, was mainly contributed by the nestedness-resultant component (76.6–84.0%), especially in DLs. We found that only functional dissimilarities were significantly higher in DLs than CLs, indicating a high level of functional diversity loss without replacement of species possessing traits sensitive to hydrological disconnection (i.e., large body size, lamellibranch body form, filter feeding, ovoviviparity and burrowing habits). In general, lake area, hydrological connectivity, aquatic vegetation coverage and nutrient levels (TN and TP) played important roles in structuring variation in molluscan alpha and beta diversities, although the three diversity facets responded to different environmental factors. Our results suggest that loss of connectivity to the mainstem river has negative impacts on molluscan assemblages in floodplain lakes. More importantly, as taxonomic, functional and phylogenetic diversities responded somewhat differently to the loss of hydrological connectivity, all of these biodiversity facets should be better incorporated into aquatic biodiversity assessment and conservation programs in large river floodplains.
The flood plain of the Medveditsa River in the middle current is characterised by various fauna of birds. Nowadays significant transformations of local fauna, influenced by climatic conditions and anthropogenous loadings, are observed. In the valley of the river the most significant factor influencing communities of birds is the flood mode. The purpose of the work is the birds faunogenetic structure analysis of the Mededitsa river flood plain, and also it`s dynamics under the conditions of degradation of an inundated hydrological cycle. Collecting field data was carried out on the territory of the Medveditsa River valley between the Uritsky village (55.43 ° EL of 44.93 °N) and Atayevka village (51.17 ° EL 44.50 °N) of Lysogorsky district of the Saratov region in May-July, 2013–2016. The methods of research included the birds quantitative accounting, mapping of nesting sites, selection the faunogenetic complexes, determination of the birds residence status in habitats. Assessment of statistical similarity of species quantity in various ecological groups of birds under the conditions of the changing water content of a flood plain was carried out by means of Mann-Whitney nonparametric U-criterion. During the observations period the manifolding of 117 bird species which are falling into nine faunogenetic complexes was confirmed. According to their ecological adaptations birds fall into dendrofila, limnofila, sklerofila, types of open spaces, evritopa and sinantropa. The species having relationship with the European broad-leaved woods, Palearktik's woods, as well as widespread azonal palearkta, prevail among them. Representatives shares of the Mediterranean, Manchurian, steppe and desert and taiga fauna are small. The Arctic and hypoarctic birds meet in the Medveditsa River valley during seasonal migrations. Degradation tendency of the annual Medveditsa River hydrological cycle was identified: a frequency of anomalously low floods is ascending and abundantly high waters occur once in seven-ten years. As a result, we observe Essential structural change of habitats the limnophilic of the birds dated for reservoirs of the central flood plain and a priterrasye. The analysis of the U-criterion calculated by quantity of the nesting in different years limnofila, dendrofila types and birds of open spaces, showed that water content of a flood plain does not influence significantly the structure of birds communities (U emp > U0.05). We identified a certain difference (U emp< U0.01) in quantity of breeding individuals of the limnofila birds in the years with the maximum and minimum levels of the priterrasny Lebyazje lake on the model platform.
Warming, eutrophication, and increased omnivory by small-sized fish are global change processes that induce major effects on the food web structure and primary producers of shallow lakes. Despite the key relevance of phytoplankton and periphyton in freshwaters, the combined and potential synergistic effects of fish omnivory, warming and eutrophication, especially on periphyton, remains little addressed, particularly for subtropical shallow lakes. We experimentally tested the food web effects on phytoplankton and periphyton induced by small visually feeding omnivorous fish (Rhodeus ocellatus), high nutrient enrichment and warming (+4.5 °C) in thirty-two 1000 L-mesocosms simulating littoral conditions of subtropical shallow lakes. We aimed at analysing the mechanisms and responses of periphyton and phytoplankton to these experimental factors. All mesocosms included the submerged macrophytes Vallisneria denseserrulata and Potamogeton lucens and artificial plants at 50% plant volume inhabited, plankton and macroinvertebrates. Small-sized visually feeding omnivorous fish enhanced phytoplankton dominance and periphyton loss. These changes coincided with a decrease in zooplankton biomass and a diversity loss of both zooplankton and macroinvertebrates as well as an increase in snail abundance. Fish presence led to a collapse of cladocerans, thereby releasing the grazing pressure on phytoplankton, and predator and collector macroinvertebrates were replaced with small snails (Radix peregra < 0.5 cm) resulting in enhanced grazing on periphyton. Eutrophication reinforced the fish effects, while warming had weak or no effects. Our results indicate that omnivory by small-sized visually feeding fish may induce stronger effects on the food webs of shallow lakes, towards phytoplankton-dominated states, than the combined effect of nutrient enrichment and warming under the present experimental conditions.
The structure and dynamic of mollusk communities, as well as environmental factors influencing them, were analysed under conditions of small oxbow lakes in the forest-steppe zone (a case of the Khoper river valley, Penza region). 19 species of mollusks were found in the studied water bodies. The oxbows were characterized by relatively low alpha-diversity (number of species 4 ± 2) with relatively high beta-diversity (Jacquard index 0.26 ± 0.18), which is typical for floodplain ecosystems. Lake communities was dominated by Planorbis planorbis (40 %), Lymnaea stagnalis (15 %), Anisus spirorbis (14 %), Lymnaea saridalensis (9 %), Anisus vortex (8 %). The results of our analysis showed that the group of factors that determined the type of water body (stability, light intencity, water temperature, oxygen concentrations) had the greatest impact on the structure of malacocenoses. The seasonal dynamics of mollusk communities was determined by the number of adjoining water bodies, water temperature, and dissolved oxygen concentrations. The number of adjoining oxbows influenced species diversity the most, as well as the total number and biomass – isolation was more favorable for mollusk communities. The factors influencing the highest number of mollusks species (seven) were the light intencity and the presence of fish. Other significant factors were the stability of lakes (five species of mollusks), the number of oxbows and the transparency of the water (four species). Aquatic vegetation positively correlated with only one species – Anisus vortex. Our data suggest that the presence of fish could influence the abundance of Lymnaea saridalensis. The mollusks themselves, apparently, had a positive effect on the number of leeches in water bodies. The most sensitive to the factors were Lymnaea stagnalis, Lymnaea saridalensis, Aplexa turrita, Anisus spirorbis and Anisus leucostoma, the most tolerant were Bathyomphalus crassus, Anisus vortex, Planorbis planorbis, Planorbarius corneus
The structure of spawning taxocenoses of anuran amphibians in five floodplain lakes of the Medveditsa river valley in 2009-2018 is analysed. Two near-terrace lakes (Lebyazhye and Kob-lovo) and three lakes of the central floodplain (Sadok, Kruglen'koye, and Cherepashie) were used as model ones. The degradation of the populations of the three most numerous species, a decrease in the dominance degree of the common spadefoot toad were established. Degradation is more characteristic of species with a longerer distance of spawning migrations-the severity of changes consistently decreases in the row of species: Pelophylax ridibundus → Pelobates fuscus → Bombina bombina. Indices of the structure of amphibian communities in the near-terrace lakes Le-byazhye and Koblovo were stable. Against the background of low water content and unstable hydrological regime of the central floodplain lakes with a survey duration of five or more years, three periods were established to characterize the structure of spawning amphibian taxocenoses, namely: a stable structure, a sharp decrease in dominance and an increase in evenness, and an increase in the variability of the main attributes of the structure. At the end of the third period, which characterizes the structure of taxocenoses, some stabilization of the main parameters was noted with an extremely low number of mature individuals of all amphibian species. The high level of spring flood of the Medveditsa river in 2018 determined the beginning of the exit from the abnormally long period of low water content of the spawning lakes in the floodplain (from 2009 till 2017) and their functioning in the hydrological regime as temporary water bodies. The sudden increase in water content of the floodplain lakes and the extension of their hydroperiod allow the beginning of the recovery process of the population size and community structure of anuran amphibians to be noted.
Evidence is increasing for positive effects of α-diversity on ecosystem functioning. We highlight here the crucial role of β-diversity - a hitherto underexplored facet of biodiversity - for a better process-level understanding of biodiversity change and its consequences for ecosystems. A focus on β-diversity has the potential to improve predictions of natural and anthropogenic influences on diversity and ecosystem functioning. However, linking the causes and consequences of biodiversity change is complex because species assemblages in nature are shaped by many factors simultaneously, including disturbance, environmental heterogeneity, deterministic niche factors, and stochasticity. Because variability and change are ubiquitous in ecosystems, acknowledging these inherent properties of nature is an essential step for further advancing scientific knowledge of biodiversity-ecosystem functioning in theory and practice.
Interannual variations in species richness and quantitative parameters of macrozoobenthos in floodplain lakes of the Khoper Nature Reserve have been studied to reveal their dependence on flood regime and overgrowth by macrophytes. It has been shown that a particular species richness of macrozoobenthos is preserved for several years. Interannual variations in characteristics of lakes, particularly in the flood period, determine the changes in quantitative parameters of macrozoobenthos. The overgrowth rate of lakes by macrophytes does not exert an effect on species richness and quantitative parameters of macrozoobenthos, but determines its saprobiological structure. The flood period necessary for the formation of the most abundant communities of macrozoobenthos in the studied lakes is 30 days. Nevertheless, this is not the main factor determining its quantity in lakes constantly connected with the river by a channel. It is confirmed that drying or a sharp drop in water content of the river play the role of a trapping point and triggers ecosystem transformations in small water bodies.
From the very first steps in the development of Russia’s network of nature reserves, academic science by means of its individual representatives, scientific establishments, and committees and commissions of the USSR and then Russian Academy of Sciences began to elaborate its scientific and methodological substantiation. This was implemented most effectively by the Central Department for Science, Art, and Museum Establishments (Glavnauka) of the People’s Commissariat for Education of the Russian Soviet Federative Socialist Republic in the 1920s, the Scientific–Methodological Bureau of the Committee for Nature Reserves under the Central Executive Committee of the Soviet Union (Department for Nature Reserves under the Council of People’s Commissars of the Russian Soviet Federative Socialist Republic) in the 1930s, the Commission on Nature Reserves of the USSR Academy of Sciences (1952–1955), the Commission for Nature Protection of the USSR Academy of Sciences (1955–1963), the Commission for Coordination of Scientific Research in USSR State Nature Reserves (1982–2002), and the Section for Nature Reserves of the RAS Commission on the Preservation of Biological Diversity (from 2002). In addition to scientific-methodological support and coordination of the scientific activity of nature reserves, ideas about how to form a geographical network and integrate it into the country’s spatial development were also proposed by the above structures.
For at least two centuries, the lateral mobility of the meandering reaches of the Cher River (France) has been very low. This article aims to identify the main causes of this behavior. Two not-mutually exclusive explanatory hypotheses are proposed. Under the first hypothesis, the natural mechanisms of loop migration would have been inhibited or blocked by the presence of bank protections. Under the second hypothesis, a decrease in the frequency and/or intensity of morphogenic hydrological events since the nineteenth century would have reduced the frequency of bedload mobilization and/or reduced the capacity of the river to erode its banks. To test these hypotheses, the diachronic evolution of the planform was reconstituted at different time scales using a GIS and field surveys. Morphological transformations were characterized and quantified (eroded and vegetated areas, length of eroded banks, rates of bank retreat) and the critical discharges of bedload mobilization and of lateral erosion were estimated. Engineering works in the riverbed were identified and, when possible, dated. The results show that meander morphodynamics have been highly constrained and disrupted by engineering works, probably for over a century. However, the meanders still have noticeable potential for bedload mobility and lateral erosion, and hence for self-restoration.
Small, adventitious tributaries (<3 orders of magnitude smaller than the stream it flows into) are a conspicuous feature of many river–floodplain systems, but their value as fish reproduction and nursery habitat is not well understood compared to oxbow lakes and the main river channel (MRC). Moreover, connectivity of tributaries to the MRC is often less impacted by anthropogenic modifications (e.g., dams and levees) compared to oxbow lakes. From April to July 2012, larval and juvenile fish were collected in the Fourche LaFave River (Arkansas, USA) system to better understand fish nursery habitat function of tributaries relative to oxbow lakes and the MRC. Nonmetric multidimensional scaling ordination of juvenile and larval fish genera revealed distinct fish assemblages in MRC and floodplain habitats. Ordination of juvenile fish at the species level resulted in distinct fish assemblages in tributary versus oxbow lake habitats. Tributaries had more unique species and higher abundance of shared species than oxbow lakes and MRC. Additionally, of the 46 species identified, all but six were collected in lower tributary reaches. Connectivity was strongly associated with both ordinations and was important in describing patterns of fish variation among habitats and between tributaries. Of the tributaries sampled, the least fragmented stream had the most similar fish assemblages between upper and lower sections. Findings of this study revealed tributaries are an important, yet overlooked, feature in the river–floodplain model. Especially in years of drought, channel–floodplain connectivity can be limited, but tributaries can be used by fishes for reproduction and nursery habitat.
The study shows that the zooplankton of the lake, which annually is connecting with the river, has maximum number of species, the value of the coefficient of nutrient status, abundance, and biomass. Very long period of flooding, as well as the first flooding of mesotrophic-eutrophic sites of reservoirs after several years of lack of connection with a river, cause a restructuring of zooplankton, which is observed under increasing organic income. The first flooding of hypertrophic areas of reservoirs leads to changes in the structure of zooplankton, a number of parameters of the structure of zooplankton indicates the reduction of the organic income. Recovering of mode of flooding in the second year maximally homogenizes conditions of development of zooplankton in floodplain lakes of different types.
By zooplankton indices, the lakes of the Khopyor River flood plain in the reserve area can be classified as eutrophic–hypertrophic reservoirs. In the years of intensive overflow of the Khopyor River, the trophic level of the flood plain lakes has been revealed to increase; the variety, numbers, biomass, and relative abundance of rotifers in the zooplankton increase. It is most evident in the coastal zone, where the total number and biomass of the zooplankton decreases. In the central parts of the lakes, the number and biomass of zooplankton increase, as does the proportion of crustaceans and the variety of rotifers. In the zooplankton of the central parts of the reservoirs with the longest term of coastal flooding after high water, the fraction of rotifers in the total number and the biomass of zooplankton communities increases. Simultaneously, the annually flooded lakes are characterized by maximum specific richness.
The pros and cons of the old saprobic system are discussed with a view to select the good ideas from the older attempts, to modernize present methods, and to establish the fundamentals for a future universal system of water quality. In addition, the author proposes an open saprobic system, able to be supplemented, modernized and computerized. The first and main component of the system is the amount and intensity of decomposition of autochthonous as well as allochthonous organic matter in water as reflected in the communities. As the main theoretical assumptions of the saprobity system the following two principles are considered: dependence of saprobic organisms on the environment, and successions, occurring in two directions. The second main component of the system of water quality is the toxicity, expressing the toxic effects of chemical compounds on aquatic organisms and their communities. The third main component of the system is the radioactivity, indicating the amount of natural and artificial nuclides in water and aquatic organisms.