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The Qaidam Basin in China, recognized for its copious salt lake mineral resources, holds immense significance for the nation’s sustenance and industrial progression. However, the escalating exploitation of these resources has led to substantial conflicts between economic pursuits and ecological conservation. Ongoing activities like water diversion for flood control and brine extraction are hindering the preservation of the lake’s natural ecosystem. This study examines the challenges of salt lake exploitation and ecological conservation, proposing measures for environmental stewardship. These include delineating the responsibilities of production zones designated for salt lake development; advocating the comprehensive harnessing of flood resources; and establishing a collaborative platform for integrating ecological data among government entities, regulatory bodies, and private enterprises. This research aims to lay the groundwork for ecological management policies for salt lakes in the Qaidam region to balance the development of a top-tier salt lake production base with environmental preservation.

Despite previous studies, glacier–lake interactions and future lake development in the Poiqu River basin, central Himalaya, are still not well understood. We mapped glacial lakes, glaciers, their frontal positions and ice flow from optical remote sensing data, and calculated glacier surface elevation change from digital terrain models. During 1964–2017, the total glacial-lake area increased by ~110%. Glaciers retreated with an average rate of ~1.4 km2 a−1 between 1975 and 2015. Based on rapid area expansion (>150%), and information from previous studies, eight lakes were considered to be potentially dangerous glacial lakes. Corresponding lake-terminating glaciers showed an overall retreat of 6.0 ± 1.4 to 26.6 ± 1.1 m a−1 and accompanying lake expansion. The regional mean glacier elevation change was −0.39 ± 0.13 m a−1 while the glaciers associated with the eight potentially dangerous lakes lowered by −0.71 ± 0.05 m a−1 from 1974 to 2017. The mean ice flow speed of these glaciers was ~10 m a−1 from 2013 to 2017; about double the mean for the entire study area. Analysis of these data along with climate observations suggests that ice melting and calving processes play the dominant role in driving lake enlargement. Modelling of future lake development shows where new lakes might emerge and existing lakes could expand with projected glacial recession.

This study presents a high-resolution, multi-proxy palaeoenvironmental reconstruction of the Tövises fen at Pocsaj, Hungary, utilising lithostratigraphical, geochemical, malacological, and palynological analyses supported by radiocarbon dating. The sedimentary sequence documents the transition from a Late Glacial fluvial system (c. 19,000–16,000 cal BP) to a cut-off meander and subsequent oxbow lake, eventually evolving into a peat-forming fen. Malacological and palynological data reveal the co-occurrence of cold-tolerant Late Pleistocene elements and the early appearance of thermomesophilous taxa at the onset of the Holocene. This suggests that the favourable microclimate of the adjacent loess-covered high bank and the humid alluvial plain functioned as a cryptic refugium for temperate broad-leaved trees and associated fauna during the Late Glacial. Anthropogenic impact is traceable from the Mesolithic, characterised by Corylus management, intensifying through Neolithic agriculture to a peak during the Roman Imperial Period. Geochemical markers in the upper peat sequence reflect increased biomass and medieval habitation, while recent malacofaunal shifts indicate progressive desiccation. Despite modern drainage attempts, the Tövises fen remains a biodiversity hotspot of high conservation value, preserving relict wetland communities.

This study presents a detailed analysis of geochemical and biotic proxies in a lake sediment profile to assess the effects of local and regional environmental drivers on the Holocene development of Lake Loitsana, situated in the northern boreal forest of NE Finland. Multi-proxy studies, in particular those that include a detailed plant macrofossil record, from the part of the northern boreal zone of Fennoscandia which has not been affected by treeline fluctuations, are scarce and few of these records date back to the earliest part of the Holocene. A 9-m sediment sequence of gyttja overlying silts representing the last c. 10,700 cal year, allowed for a high-resolution study with emphasis on the early to mid-Holocene lake history. The lacustrine sediments were studied using lithology, loss-on-ignition and C/N ratios, micro- and macro-fossils of aquatic and wetland taxa, diatoms, chironomids and accelerator mass spectrometry ¹⁴C dating on terrestrial plant macrofossils. Our study shows that the local development at Loitsana was complex and included a distinct glacial lake phase and subsequent drainage, a history of fluvial input affected by nearby wetland expansion, and lake infilling in an eventual esker-fed shallow lake. Enhanced trophic conditions, due to morphometric eutrophication, are recorded as Glacial Lake Sokli drained and open water conditions became restricted to a relatively small Lake Loitsana depression. pH appears to have been stable throughout the Holocene with a well-buffered lake due to the local carbonatite bedrock (Sokli Carbonatite Massif). The fossil assemblage changes are best explained by a complex mixture of drivers, including water-body conditions (i.e. depth, turbidity and turbulence), rate of sediment input, and the general infilling of the lake, highlighting the need to carefully evaluate the possible influence of such local factors as palaeoenvironmental conditions are reconstructed based on aquatic proxies.

Lake depth is an important limnological attribute defining the structure and function of freshwater aquatic ecosystems. Lake levels have fluctuated and lake depths changed through the Holocene reflecting regional climate variations and sediment accumulation. Cladoceran remains preserved in sediments have been widely used for qualitative (P/L ratio) and quantitative (inference models) lake-depth reconstructions. In addition to estimations of prediction errors for performance power of modern data sets, it is important also to evaluate the reliability of reconstructed environmental values and to ensure that they are ecologically and paleoclimatically meaningful. In this study, we reconstructed the Holocene lake-depth history of a northern boreal lake using the Cladocera P/L ratio and a Cladocera—lake-depth inference model. These results were evaluated by comparison with reconstructions based on other proxies (aquatic macrofossils, sediment composition and sedimentation pattern) derived from three radiocarbon-dated sediment cores from the same lake. Whilst the reconstructions based on Cladocera and on the combination of other proxies yielded similar long-term trends, the absolute water depth values derived from the quantitative cladoceran model deviated from what was indicated by the other proxies. Therefore, we strongly recommend that also other, independent methods should be used simultaneously when reconstructing past water depths using Cladocera remains.

In 1978, Canada and the United States concluded an agreement for the protection and enhancement of water quality in the Great Lakes based on the ecosystem approach to management. Since ratification of this agreement, little progress has been made in practical application of this concept to basin-wide management for the Great Lakes. At the same time public concern for the quality of the Great Lakes and their future has risen dramatically. As a result, the need has arisen for a practical, authoritative explanation of the ecosystem concept. This volume, written by highly qualified authorities, addresses these important ecological, political, and economic issues in a systematic and informative manner.In this study, the ecosystem concept and its objectives are defined. The institutional structure that has evolved for governance of the Great Lakes, the need for a more effective governance structure, and prospects for rehabilitation of the Great Lakes Waters are crucial issues considered. The management question is the single most important policy question with respect to the Great Lakes and this is the only study available that brings together all pertinent information and provides steps for new and constructive management of the Great Lakes.

Multiproxy palaeoecological data for lake Dallund Sø, Denmark, were synthesized to explore the link between changes in the terrestrial environment (from pollen, and sediment physical properties) with those in the aquatic environment (from diatom, macrofossil, zooplankton and Pediastrum data) since the introduction of agriculture c. 6000 years ago. The lake was relatively insensitive to catchment disturbance during the Neolithic (3870-1700 BC) and Early Bronze Age (1700-1000 BC) periods but was dramatically impacted by environmental changes associated with a major deforestation phase at the transition from the Late Bronze Age (1000-500 BC) to the Pre-Roman Iron Age (500 BC-AD 0). A major eutrophication of the lake took place as a result of a changing agricultural system and also the retting of flax and hemp during the Mediaeval period (AD 1050-1536). Analyses of the data sets representing the terrestrial and aquatic environments demonstrate that human activities over thousands of years have not only impacted and shaped the Danish landscape but have also played a major role in lake development.

Pollen and plant macrofossil analysis of an 11-m sediment core from Dallund Sø, a lake situated in the plains of north Funen, Denmark, provide a record of the last 7000 years of vegetation history in response to changing land-use practices. Around 3900 BC, a distinct Ulmus decline is registered. The first agricultural activity is evidenced c. 400 years after the elm decline by the occurrence of cereal pollen (Avena/Triticum-type). Shortly after this, the Neolithic 'landnam' sensu Iversen was detected. Around the transition Late Bronze Age/Pre-Roman Iron Age (500 BC), extensive forest clearances followed by a major expansion of grazing areas, cultivated fields and meadows was inferred. The immigration time of Fagus is hard to identify but a threshold percentage > 2 was reached c. 700 BC, suggesting a local presence of Fagus woodland by then. In the Late Iron Age (AD 400-AD 1050), rising abundances of cereal and Cannabis-type pollen indicate increased arable farming. A contemporary Fagus/Quercus woodland expansion may be due to a change in the agricultural system. Linum-retting in the lake in this period is suggested by the macrofossil record. At the beginning of the Mediaeval period, new major deforestation was inferred, accompanied by a massive expansion of arable farming (cereals, Fagopyrum, Linum, Cannabis). Extensive Linum-retting in the Mediaeval period is documented by the macrofossil record and high values of Cannabis-type pollen in the sediments also suggest intensive retting of hemp plants. In the seventeenth and eighteenth centuries the catchment probably witnessed the strongest agricultural impact of the last 7000 years.

Analyses of pollen, microscopic charcoal, loss on ignition (LOI) and chironomids in the sediment of the small sub-alpine lake Kichikol (2541 m a.s.l.; 39°59'N, 73°33'E; Alay Range, Kyrgyzstan) provide new data to reconstruct the vegetational and lacustrine history during the past 6300 years. From 6300—5100 calibrated 14C years BP (cal. yr BP) semi-deserts with Chenopodiaceae and Ephedra and rather open Juniperus stands persisted around the lake. At 5100—4000 cal. yr BP dense Juniperus forest established. Around 4000 cal. yr BP the forest retreated and was probably restricted to north-facing slopes, as is the case today. Changes in the hydrology of Kichikol are inferred from lithological properties, pollen of aquatic plants and remains of aquatic invertebrates. The lacustrine development of Kichikol suggests a step-wise increase in humidity during the mid and late Holocene, with major shifts recorded at 5000 and 4000 cal. yr BP. At the beginning of the record Kichikol was a very shallow, possibly temporary pond. An initial rise in water-table is registered at c. 5000 cal. yr BP, followed by a second rise to near present levels at c. 4000 cal. yr BP. These hydrological shifts could be related to an increase of westerly moisture transport from the Mediterranean region as a consequence of a late-Holocene weakening of the Central Asian High and Indian monsoon systems. Moderate human impact in the region is recorded after 2100 cal. yr BP, as indicated by pollen of Plantago lanceolata-type and a slight increase of charcoal accumulation rates. Considering the general course of climate as well as human impact we conclude that the present forest composition is natural or quasi-natural.

Diatom, macrofossil, pollen, Pediastrum and biogenic silica analyses were carried out on an 11-m sediment sequence from the Danish lake Dallund Sø, demonstrating major changes in the aquatic ecosystem over the last 7000 years. A diatom-phosphorus calibration model was applied to the fossil diatom record to reconstruct in-lake total phosphorus (TP) concentrations over this period. Prior to the introduction of agriculture to the region, c. 6000 years ago, the lake was relatively deep and had low diatom-inferred TP concentrations (c. 20 υg TP/L), with limited macrophyte growth. Moderate nutrient enrichment of the lake was inferred during the Bronze Age (1700-500 Bc) and Iron Age (500 BC-AD 1050) periods and evidence for water-level lowering was observed. Marked eutrophication of the lake (reconstructed TP levels consistently > 100 υg/L) was associated with major changes in agriculture during the Mediaeval period (AD 1050-1536) and continued to the present day. These data document the long-term anthropogenic impact on Dallund Sø, a lake in an area with a long history of human activity.