In the past 20 years, karst desertification control has produced remarkable results, and the South China karst has been a global hotspot for greening. However, in the new stage of karst ...desertification control, the functional lag of forest ecosystems and the insufficient supply capacity of ecosystem services are gradually becoming prominent. We not only lack systematic research on vulnerability and resilience, structure and stability, ecological assets and services, carrying capacity and ecological security, and service trade-offs/synergies and optimization in controlled ecosystems. There is still a lack of research on the ecological processes of newly constructed forests in improving ecosystem functions and services. Therefore, this reprint mainly focuses on the research improvement of forest ecosystem functions in karst desertification control. This includes the improvement mechanism of ecosystem structure, function, and services, the mechanism of ecosystem service tradeoff/synergy, and function optimization. An optimization model of ecosystem function and an improvement path for eco-product supply are introduced. The role of functional traits in the maintenance of ecological function and services is also established, and social–ecological responses to afforestation in karst desertification control are discussed.
This reprint encompasses karst ecosystem quality, ecosystem services, climate change, ecological restoration, vegetation dynamics, land management, and the element biogeochemical cycle. These are ...closely related to land system science, landscape, land–climate interactions, the water–energy–land–food nexus, ecosystem services, and multifunctionality and sustainability. We expect that this reprint will contribute to ecological construction and land use management in karst areas.
This paper gives a comprehensive explanation of the hydrogeological and hydrological characteristics of different water occurrence, which exists in the extremely complex Dinaric karst system. The ...area and boundaries of the Dinaric karst have never been precisely determined. It covers about 60,000 km² stretching the length of the eastern coast of the Adriatic Sea, from the Bay of Trieste in the north, to the Drim River basin in the south, and the Western Morava River valley in the east. Due to very high infiltration rates, overland and surface flows are rare in comparison with non-karst terrains. The Dinaric karst is an extremely heterogeneous medium which can be explained only by the use of a great number of measurements points and by continuously monitoring and measuring different parameters. The hydrogeological and hydrological regime of all water phenomena in the Dinaric karst depends mostly upon the interaction between groundwater and surface water. The dominant flow of the groundwater contained in the Dinaric karst is towards the Adriatic Sea through rivers and many permanent and intermittent coastal and submarine springs. The paper presents many examples of karst water phenomena from the Dinaric karst: (1) springs (Jadro, Ombla and Crnojevića Springs); (2) open streamflows (Ljubljanica, Pazinčica, Dobra, Lika, Gacka, Krka, Zrmanja and Cetina Rivers); (3) lakes and wetlands (Cerknica, Vrana, Plitvice, Vransko, Red and Blue Lakes); and (4) coastal and island karst (Brač Island).
Karst aquifers contribute substantially to freshwater supplies in many regions of the world, but are vulnerable to contamination and difficult to manage because of their unique hydrogeological ...characteristics. Many karst systems are hydraulically connected over wide areas and require transboundary exploration, protection and management. In order to obtain a better global overview of karst aquifers, to create a basis for sustainable international water-resources management, and to increase the awareness in the public and among decision makers, the World Karst Aquifer Mapping (WOKAM) project was established. The goal is to create a world map and database of karst aquifers, as a further development of earlier maps. This paper presents the basic concepts and the detailed mapping procedure, using France as an example to illustrate the step-by-step workflow, which includes generalization, differentiation of continuous and discontinuous carbonate and evaporite rock areas, and the identification of non-exposed karst aquifers. The map also shows selected caves and karst springs, which are collected in an associated global database. The draft karst aquifer map of Europe shows that 21.6% of the European land surface is characterized by the presence of (continuous or discontinuous) carbonate rocks; about 13.8% of the land surface is carbonate rock outcrop.
Eighty-one karst types and their main characteristics are described in this study, including the conditions of their development, the main characteristics of their karstification and their ...characteristic features. The classification includes the karst types of the Earth, a concise description of each karst type and the possibilities of belonging to several types of various karst areas. The classification of types is hierarchical in terms of groups, subgroups, types and subtypes. Karst can be classified according to their momentary state (the group of static karst types) and to their development (group of dynamic karst types). The group of static karst types has the azonal and zonal subgroups. zonal karst types may be situated under any climate. These karst types are categorized according to their geological characteristics (age of karstification, constituting rock, extent of coveredness, structure), their elevation, expansion, the morphology of their surface, hydrology and to the effects occurring on the karst. Taking the above mentioned factors into consideration, the author distinguishes various types and describes their characteristics. Zonal karst types are also described (tundra karst, temperate karst, subtropical karst, tropical karst), karst types that can be distinguished based on their geomorphic evolution are identified and their characteristics are presented.
Karst aquifers are one of the main potable water sources worldwide. Although the exact global karst water utilisation figures cannot be provided, this study represents an attempt to make an upgraded ...assessment of earlier and often circulated data. The main objective of the undertaken analysis is not only to provide an assessment of the utilisation of current karst aquifers, but also to estimate possible trends under various impact factors such as population growth or climate changes. In > 140 countries, different types of karstified rocks crop out over some 19.3 × 10
6
km
2
, covering > 14% of ice-free land. The main ‘karst countries’, those with > 1 × 10
6
km
2
of karst surface are Russia, USA, China and Canada, while among those with > 80% of the territories covered by karst are Jamaica, Cuba, Montenegro and several others. In contrast, in a quarter of the total number of countries, karstic rocks are either totally absent or have a minor extension, meaning that no karst water sources can be developed. Although the precise number of total karst water consumers cannot be defined, it was assessed in 2016 at approximately 678 million or 9.2% of the world’s population, which is twice less than what was previously estimated in some of the reports. With a total estimated withdrawal of 127 km
3
/year, karst aquifers are contributing to the total global groundwater withdrawal by about 13%. However, only around 4% of the estimated average global annually renewable karstic groundwater is currently utilised, of which < 1% is for drinking purposes. Although often problematic because of unstable discharge regimes and high vulnerability to pollution, karst groundwater represents the main source of potable water supply in many countries and regions. Nevertheless, engineering solutions are often required to ensure a sustainable water supply and prevent negative consequences of groundwater over-extraction.
Large areas of Europe, especially in the Alps, are covered by carbonate rocks and in many alpine regions, karst springs are important sources for drinking water supply. Because of their high ...variability and heterogeneity, the understanding of the hydrogeological functioning of karst aquifers is of particular importance for their protection and utilisation. Climate change and heavy rainfall events are major challenges in managing alpine karst aquifers which possess an enormous potential for future drinking water supply. In this study, we present research from a high‐alpine karst system in the UNESCO Biosphere Reserve Großes Walsertal in Austria, which has a clearly defined catchment and is drained by only one spring system. Results show that (a) the investigated system is a highly dynamic karst aquifer with distinct reactions to rainfall events in discharge and electrical conductivity; (b) the estimated transient atmospheric CO2 sink is about 270 t/a; (c) the calculated carbonate rock denudation rate is between 23 and 47 mm/1000a and (d) the rainfall‐discharge behaviour and the internal flow dynamics can be successfully simulated using the modelling package KarstMod. The modelling results indicate the relevance of matrix storage in determining the discharge behaviour of the spring, particularly during low‐flow periods. This research and the consequent results can contribute and initiate a better understanding and management of alpine karst aquifers considering climate change with more heavy rainfall events and also longer dry periods.
The investigated karst system contributes to the transient atmospheric CO2 sink with about 270 t/a.
Carbonate denudation rates vary between 23 and 47 mm/1000a.
Rainfall‐discharge modelling results indicate the importance of matrix storage particularly during low‐flow periods.
Electrical conductivity (EC) of karst spring discharge has always been a fundamental variable to characterize karst systems. However, to incorporate EC into the lumped hydrologic modeling is ...challenging but has a huge potential since EC observations are widely collected. In this study, we present a new framework to integrate EC into lumped karst hydrological models for model structure identification and parameter uncertainty reduction. Our framework is tested in a small, well‐instrumented karst catchment near Guilin city (China) where EC dynamics are mostly controlled by the dissolution of carbonate rock and dilution by event water. Four karst models with different structures were equipped to consider the linear growth of EC with the carbonate rock dissolution and its mixing within the karst system. Applying a parameter estimation framework that accounts for uncertainty in discharge and EC simulations, we find that all hydrologic models obtain similar performances concerning spring discharge. However, their performances in simulating spring EC strongly differ permitting us to identify the most realistic model out of the four model structures. Our analysis further shows that including EC into parameter estimation reduces parameter uncertainty concerning concentrated flow in the conduits and helps to estimate immobile water storage in the system. Consequently, our new framework to include EC in karst models provides new directions for the more realistic simulation that can easily be transferred to other karst systems where EC dynamics are controlled by rock dissolution and dilution by event water.
Key Points
A new framework to integrate electrical conductivity (EC) observations into lumped karst hydrologic models is presented
Spring EC shows a high potential for more realistic modeling
Incorporation of spring EC in models can reduce parameter uncertainty concerning concentrated flow in the conduits
PDF
