Contributions to karst ecohydrology

Environmental Geology, 2009

Ecohydrology can be defined as the science of integrating hydrological and biological processes over varied spatial and temporal scales. There exists in karst a strong and direct interaction between the circulation and storage of groundwater and surface water. These fluxes in turn affect the spatial distribution of organisms in these habitats. Because of the fact that the appearance, storage and circulation of water in karstified areas is significantly different from other more homogenous and isotropic terrains, karst ecohydrology should develop original methods and approaches. At the same time, traditional approaches are also very useful. Large karst underground geomorphological patterns occur in many sizes and varieties, ranging from a few meters long or deep to very large, the deepest being deeper than 1 km and longer than hundreds of kilometres. In this article, special attention is paid to ecohydrological functions of karst underground features (caves, pits, conduits, etc.), which play a crucial dual role in (1) hydrology and hydrogeology of water circulation and storage and (2) ecology of many rare and endangered species. Differences in morphology, hydrology, hydrogeology and climate have resulted in a range of different environments, which provide the opportunity for the coexistence of different species. The role of the epikarst and vadose zones, as well as caves in ecohydrological processes, is discussed. The importance of the flood factor in karst ecology is analysed. The aim of this article is to move forward the discussion among different disciplines to promote and develop a conceptual framework for karst ecohydrology.

Karst represents a specific area consisting of surface-relief and surface- underground hydrographic networks resulting from water circulation and its aggressive chemical and physical action in conduits, joints, fractures, bedding plains and cracks along the layers of soluble rocks. It is a highly vulnerable and variable water and ecological system in both time and space. Karst systems have great significance for biodiversity conservation and very often they represent important cultural heritage. Karst ecosystems have been indicated as priority parts of biological and landscape diversity protection, which requires a specific approach. The objective of this paper was to analyse anthropogenic influences on the karst environment using concepts of karstology and karst ecohydrology. The paper describes some special issues on which karstology and karst ecohydrology should focus their interests: caves, karst landscape, dry stonewalls, stone clearing and wildfires in karst regions.

slo/it), Paul Tout (it/eng) design By Ideodizajn d.o.o pUBlished By Padova University Press printed By Present d.o.o.

Acta Carsologica, 2010

Besides t�e possible future impacts of climate c�ange, t�ere are many ot�er urgent groundwater-related environmental problems. Accessibility to safe drinking water in sufficient quantities for �uman needs is t�reatened by different types of contamination, overexploitation, saltwater intrusions, and inappropriate irrigation practices. Soil erosion, natural disasters, and t�e protection of ecosystems and biodiversity are ot�er important water-related issues. These problems exist today, but will get worse in many regions according to t�e current climate c�ange scenarios. All of t�ese issues are interrelated and are especially relevant in karst areas. For example, deforestation leads to ecosystem degradation and a loss of biodiversity, but also promotes soil erosion (Fig. 1), w�ic� increases t�e vulnerability of groundwater resources to contamination, alters rec�arge processes and reduces t�e water storage and buffering capacity of t�e �ydrogeologic system, t�us posing a t�reat to quality and quantity of drinking water and ultimately to public �ealt�. Furt�ermore, t�e degradation of soil and vegetation also releases CO 2 and reduces t�e efficiency of karst processes as a natural sink of t�is green�ouse gas (Liu & Z�ao 2000). Finding solutions to all of t�ese problems requires a multidisciplinary approac�, to w�ic� karst and groundwater researc�ers could and s�ould contribute more t�an t�ey currently do.

Geologos

2006

El medio calcáreo contiene masas de agua discontinuas, yendo de las capas acuíferas casihomogéneas fisuradas a las muy carstificadas, en función de su historia geológica. Se puede clasificar tres niveles de heterogeneidades en sectores carbonatados: la vertical, con una zona no saturada separada en el epikarst y la zona no saturada que se extiende sobre la zona saturada, spacial con bloques microfisuradas odeados por conductos y subsistemas anexo-a-drenes, en la recarga con la infiltración difusa, localmente concentrada en depresiones del carst, y finalmente la recarga puntual en ponors. Este grande diversidad, gracias a las condiciones geoquímicas variadas producidas por las condiciones del medio ambiente (medio abierto o cerrado para oxygenio o gás carbónico, conductividad hidraulica y tiempo de residencia correlacionado,...) permite trazados especificos, visibles a los exutorios del sistema (manantiales, sondeos), a pesar del contexto litológico más bien homogéneo.

2015

Karst aquifers have a different hydraulic structure and behavior than porous media and therefore require specific investigation methods (Goldscheider and Drew 2007). As discussed in Chap. 3, they are characterized by a high degree of heterogeneity and discontinuity, resulting in a duality of recharge, infiltration, porosity, flow, and storage (Bakalowicz 2005; Ford and Williams 2007). Recharge either originates from the karst area itself (autogenic) or from adjacent non-karst areas that drain toward the karst aquifer (allogenic). Infiltration occurs diffusely through soil and epikarst or concentrated via dolines or swallow holes. Karst aquifers show double or triple porosity, consisting of intergranular pores and fractures (often summarized as matrix porosity), and solutional conduits. Flow in the network of conduits and caves is often rapid and turbulent, while flow in the matrix is generally slower and laminar (Fig. 4.1). Storage occurs in the matrix and conduits, but residence ti...

Geodinamica Acta, 2010

A holistic conceptual approach to groundwater and natural resources protection, surface and subsurface biodiversity conservation and ecosystem services in karst terrains is presented. Karst landscapes and aquifers consist of carbonate rock in which a part of the fractures has been enlarged by chemical dissolution. They are characterised by unique geomorphological and hydrogeological features, such as rapid infiltration of rainwater, lack of surface waters, and turbulent flow in a network of fractures, conduits and caves. Karst terrains contain valuable but vulnerable resources, such as water, soil and vegetation, and they provide a great variety of habitats to many species, both at the surface and underground, including many rare and endemic species. Karst systems deliver various ecosystem services and act as natural sinks for carbon dioxide (CO 2 ) thus helping to mitigate climate change. It is demonstrated that all these resources and ecosystem services cannot be considered in an isolated way but are intensely interconnected. Because of these complex feedback mechanisms, impacts on isolated elements of the karst ecosystem can have unexpected impacts on other elements or even on the entire ecosystem. Therefore, the protection of natural resources, biodiversity and ecosystem services in karst requires a holistic approach.