Karst and Caves
Some of the Earth's most dramatic landscapes are in karst areas where landforms commonly include sinking streams, blind and dry valleys, closed depressions, underground drainage and caves. They are largely a product of a process called dissolution (i.e. dissolving) acting on rocks that have a high solubility in natural waters. Solubility alone does not guarantee that a karst system will evolve. Other processes, most notably mechanical erosion and collapse, contribute to karst landform development, but dissolution is an essential precursor. Two groups of rocks are widely recognised as being karstifiable: the carbonate rocks (limestone, dolostone and marble) and the evaporite rocks (gypsum, anhydrite and salt). Surface and near-surface outcrops of these rocks occupy about 20% of the Earth's ice-free land surface. A well-developed surface karst landscape is dependent on the development of underground drainage. In carbonate rocks, groundwater flows through dissolutionally enlarged channels. When the channel diameter becomes large enough for turbulent flow it is commonly referred to as a conduit and those conduits that grow large enough for human access are called caves
A cave is a naturally formed void in an earth material that is large enough for human entry. This definition distinguishes caves from artificial tunnels and other constructed underground voids that are sometimes incorrectly referred to as caves. Caves are found in many lithologies and settings, but globally the majority are formed by dissolution of carbonate rocks. Caves formed by dissolution are also found in evaporite and, more rarely, silicate rocks. There are also a substantial number of volcanic caves (also called lava caves) whilst less common forms include piping caves, developed by mechanical removal of sediment, and tufa caves formed by deposition of carbonate minerals. In the marine setting virtually every hard rock coast contains littoral caves (also called sea caves) that are formed by mechanical processes but where carbonate rocks crop out at the coast there may also be caves that formed by dissolution close to the fresh water - saline water interface.
The CKWG Terms of Reference (ToR)
The purpose of the IUCN/WCPA/GSG Caves and Karst Working Group (CKWG) is to facilitate conservation of caves and karst and specifically:
- To provide advice and guidance on all aspects of geoheritage as they relate to the establishment and effective management of karst and caves in protected areas;
- To provide specific advice on the conservation and effective management of karst and cave geoheritage in protected areas and to prepare guidance material as appropriate;
- To identify significant karst geoheritage areas that could be formally reserved as protected areas by nations;
- To provide specialist geoheritage advice for the assessment of UNESCO World Heritage and UNESCO Global Geopark site nominations that contain caves and karst areas;
- To facilitate the integration of cave and karst geoheritage into all relevant IUCN programmes and activities;
- To provide, as appropriate, a professional interface for UNESCO/IUCN between karst and cave geoheritage stakeholders and the mining industry and others.
As the CKWG operates within the GSG there is an emphasis on geodiversity in these ToR. However, in karst in general and in caves in particular there is a strong relationship between geodiversity and biodiversity. Hence conservation and management of biodiversity and geoheritage go hand-in-hand and demand a holistic approach. In recognition of this the CKWG has established links with the IUCN Species Survival Commission Cave Invertebrate Specialist Group (CISG).
History and significant achievements
At the 1992 World Parks Congress in Venezuela a “Network on Cave Protection and Management” led by John Watson was established within the IUCN Commission on National Parks and Protected Areas (CNPPA). The CNPPA later changed its name to the World Commission on Protected Areas (WCPA) and the Network became known as the WCPA Working Group on Cave and Karst Protection. This was later renamed as the WCPA Caves and Karst Task Force and then, following an IUCN internal review, as the WCPA Caves and Karst Specialist Group (CKSG). In 2017, following another review the WCPA terminated the CKSG and in 2018 a Caves and Karst Working Group was established within the WCPA Geoheritage Specialist Group.
Over the 25+ years of its existence members of the Group have made many contributions to the management of caves and karst but the most significant publication has undoubtedly been the IUCN Protected Area Programme Guidelines for Cave and Karst Protection (Watson et al., Eds, 1997). This involved input from many land managers, speleologists, karst researchers, cave explorers and others throughout the world. Another highly important contribution was the 2008 publication: World Heritage Caves and Karst - A Thematic Study by Paul Williams with input from the Caves and Karst Task Force. This formed part of the contribution of the WCPA to the World Heritage Convention.
At the 2018 Vilm Meeting of the GSG the CKWG was given two primary goals
(a) revision of IUCN Guidelines for Cave and Karst Protection first published 1997. Professor David Gillieson, one of the editors of the 1997 document has agreed to take a lead role in the revision.
(b) producing a report on Cave and Karst geoheritage in international protected areas other than WHS, specifically Global Geoparks, sites in the World Network of Biosphere Reserves and Ramsar sites. John Gunn is leading on this and is producing databases listing sites in each category that have significant cave or karst geoheritage value.