Island Karst Research Articles

INDICATOR VALUES AND CHARACTERISTIC SPECIES OF DUNG BEETLES IN TROPICAL FORESTS OF CAT BA NATIONAL PARK, HAI PHONG PROVINCE

Dung beetles (Coleoptera: Scarabaeidae) are considered as an indicator group of habitat modifications. However, little is known about the indicative value of dung beetles for changes in tropical island karst ecosystems of Vietnam. We sampled dung beetles along the gradient of forest disturbances from primary forests to old secondary forests (> 15 years since abandonment), young secondary forests (< 10 years since abandonment) and Acacia plantations (< 10 years old) in Cat Ba National Park, Hai Phong Province. Our main aim is to detect dung-beetle species that could be used as potential indicator species of habitat changes. In total, 10 dung-beetle species were identified as potential indicator species of different forest types in Cat Ba National Park based on the indicator value (IndVal) of Dufrêne & Legendre (1997). Four species were identified as true specialists in old secondary forests including Onthophagus phanaeiformis (Boucomont, 1914), Sisyphus neglectus (Gory, 1833), Copris szechouanicus (Balthasar, 1958), and Onthophagus dorsofasciatus (Fairmaire, 1893). Three species, comprising Onthophagus sp1., Synapsis tridens (Sharp, 1881), and Onthophagus trituber (Wiedemann, 1823) could be considered as the indicator species of primary forests. Caccobius unicornis (Fabricius, 1798) and Onthophagus jeannelianus (Paulian, 1945) were indicator species of young secondary forests; Onthophagus luridipennis (Boheman, 1858) was the indicator of Acacia plantations. In the following, we gave an annotated and illustrated checklist of the indicator dung-beetle species that may be broadly useful for habitat monitoring and conservations in Cat Ba National Park.

Application of the APLIS Method for Groundwater Vulnerability Assessment in Rote Island Karst Areas

The karst area on Rote Island dominates more than 60% of the Island. The land surface conditions in karst areas are generally dry, while below the subsurface is the potential for abundant water resources. This study aims to assess groundwater vulnerability using the APLIS (Altitude, Pendiete/Slope, Lithology, Infiltration, and Soils) method that will integrate with Geographic Information System (GIS) technique. The parameters used are elevation, slope, lithology, infiltration zone, and soil type. Slope and elevation are obtained from DEM maps, the soil is obtained from soil type maps, while lithology and infiltration zone are obtained from geological maps. The lithology and the infiltration zone in APLIS method analysis have a high role in determining the level of groundwater vulnerability. The groundwater vulnerability in Rote Island was divided into four classes: very low in the Northeast, low in the South, moderate in the East and North, and high in the East and West part of the Island. It explains that a high level of groundwater vulnerability in Rote Island needs to be used as a groundwater protection zone.

Comparing and refining karst disturbance index methods through application in an island karst setting

The interconnected nature of surface and subsurface karst environments allows easy disturbance to their aquifers and specialized ecosystems from anthropogenic impacts. The karst disturbance index is a holistic tool used to measure disturbance to karst environments and has been applied and refined through studies in Florida and Italy, among others. Through these applications, the karst disturbance index has evolved into two commonly used methods of application; yet, the karst disturbance index is still susceptible to evaluation and modification for application in other areas around the world. The geographically isolated and highly vulnerable municipality of Arecibo, Puerto Rico's karst area provides an opportunity to test the usefulness and validity of the karst disturbance index in an island setting and to compare and further refine the application of the original and modified methods. This study found the both methods of karst disturbance index application resulted in high disturbance scores (Original Method 0.54 and Modified Method 0.69, respectively) and uncovered multiple considerations for the improvement of the karst disturbance index. An evaluation of multiple methods together in an island setting also resulted in the need for adding additional indicators, including Mogote Removal and Coastal Karst. Collectively, the results provide a holistic approach to using the karst disturbance index in an island karst setting and suggest a modified method by which scaling and weighting may compensate for the difference between the original and modified method scores and allow interested stakeholders to evaluate disturbance regardless of his or her level of expertise.

Cave development within a paleosol breccia in the dolomitized Seroe Domi Formation, Aruba, Lesser Antilles

Payoff Cave, found within dolomitized sections of the Seroe Domi Formation on Aruba, provides a set of diagenetic observations unique to island karst. Paleosol breccia found as wall and ceiling rock and as bedrock pillars within Payoff Cave was determined to be low-Mg calcite in mineralogy with clasts of dolomitized host limestone. Payoff Cave is interpreted to be a flank margin (FM) cave based on morphologic features. The relevant diagenetic history of this section of the Seroe Domi is: (1) dolomitization and initial cave formation, (2) collapse and paleosol breccia formation within the initial cave, (3) reoccupation of the mixing zone to form a new FM cave within the more soluble calcitic paleosol breccia, and (4) cliff retreat and exposure of Payoff Cave as found today. Dolomitization, karstification, and the presence of a paleosol breccia combine in a complex diagenetic history on Aruba.

Karst hydrogeology/hydrology of dinaric chain and isles

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 Crnojevica Springs); (2) open streamflows (Ljubljanica, Pazincica, 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 (Brac Island).

Editorial introduction to the Geokarst hazards 2009 special issue

Karst terranes are among the most unique geological features on Earth. They provide geological and archeological evidences of the evolution of life, host natural resources and form exotic landscapes upon which a large human population depends. These settings are also considered among the most vulnerable places in the world to natural and/or man-induced hazards. Preservation and sustainable utilization of natural resources and protection of local communities from risks within karst areas require a reliable understanding of karst from diverse perspectives. This is achieved through a multi-disciplinary approach, combining expertise from different fields of the geosciences and coordination with international experts in these fields. In Vietnam, karst outcrops are located for the most part in the northern part of the country and are representative of up to 30 % of the northern landmass. Natural resources upon which a large portion of the nation’s population relies are found in karst terranes and these sites are among the most important grounds for the existence of local communities. Most of the available groundwater resources of northern Vietnam are related to Paleozoic and Mesozoic karst hydro structures. Karstic regions in Vietnam are also vulnerable to geological catastrophes and natural hazards. In addition, the wellbeing of local communities in these areas is increasingly threatened by shortage of water and/or water pollution issues. Despite numerous research programs developed to study many aspects of karst geology, a thorough understanding of the nature of karst regions, their importance in local life and sustainability, and their vulnerability is lacking. To better understand the geology, natural resources, and natural and anthropogenic hazards that form the basis for wise use and sustainable management of karst areas, an international symposium on ‘‘Geology, Natural Resources and Hazards in Karst Regions (GEOKARST 2009)’’ was held in Hanoi, Vietnam, on November 12–15, 2009. The symposium was endorsed by UNESCO and jointly organized by the Hanoi University of Mining and Geology and other Vietnamese research agencies, the International Research Center on Karst (China), the University of Natural Resources and Applied Life Sciences (Austria), and the University of La Sapienza (Italy). Eight countries were represented by 26 participants from universities and research institutes around the world. They were joined by more than 60 Vietnamese participants and 200 students from universities, research institutes and geoscience societies in Vietnam and overseas. Many officials and experts from central and local government offices of Vietnam also attended. The symposium also welcomed the participation of Dr. Giuseppe Arduino of UNESCO Regional Science Bureau for Asia and Pacific Office Jakarta and Dr. James LaMoreaux, Editor-in-Chief of Environmental Earth Sciences Journal. Twenty-three oral and 14 poster presentations were presented in four technical sessions of the GEOKARST 2009. Many critical issues of karst regions were addressed including regional geology, natural resources; vulnerability, quantitative and modern approaches to the understanding of karst systems, and creative strategies and approaches to sustainable preservation and development in karst regions. The symposium was supplemented by a twoday field excursion to explore the unique geological diversity of the UNESCO Natural and Geological Heritage and Conservation Area, Ha Long Bay–Cat Ba Island karst area. H. T. Tran (&) Faculty of Geology, Hanoi University of Mining and Geology, Tu Liem, Hanoi, Vietnam e-mail: tranthanhhai.humg@gmail.com

Fuzzy-based spatial modeling approach to predict island karst distribution: a conceptual model

Previous studies have shown that island karst could successfully indicate paleoclimate change in the Quaternary Period. However, because of the relative inaccessibility of carbonate islands and their rural settings, the exploration of island karst features has been limited. To enhance future research, remote sensing and geospatial modeling were used in this study to improve the island karst exploration record. The results showed that fuzzy-based spatial modeling could successfully predict the island karst distributions on a simple carbonate island. The accuracy of the model was above 90 %. This method could apply to other coastal karst regions and carbonate islands in the future.

Void development on carbonate coasts: creation of anchialine habitats

Anchialine caves in coastal locations develop in two ways: by pseudokarst processes that form talus caves, sea caves, tafoni, fissure caves and lava tubes, and by karst dissolutional processes that form stream caves, flank margin caves, and blue holes. Pseudokarst caves are of minor importance in anchialine cave habitat development, with some lava tubes being notable exceptions. Dissolution caves provide the most extensive, variable, and long-term environments for anchialine habitats. The Carbonate Island Karst Model (CIKM) allows dissolutional cave development in carbonate coasts to be understood as the interplay between freshwater and marine water mixing, sea-level change, rock maturity, and interaction with adjacent non-carbonate rocks. Glacioeustatic sea-level changes of the Quaternary have moved all coastal anchialine cave environments repeatedly through a vertical range of over 100 m, and modern anchialine environments could not develop at their current elevations until ~4,000 years ago when sea level reached its present position. Blue holes form by a variety of mechanisms, but the most common is upward stoping and collapse from deep dissolutional voids. As a result, they provide vertical connection between different levels of horizontal cave development produced by a variety of earlier sea-level positions. Blue holes are overprinted by successive sea-level fluctuations; each sea-level event adds complexity to the habitats within blue holes and the cave systems they connect. Blue holes can reach depths below the deepest glacioeustatic sea-level lowstand, and thereby provide a refugia for anchialine species when cave passages above are drained by Quaternary sea-level fall. Blue holes represent the most significant anchialine cave environment in the world, and may provide clues to anchialine cave species colonization and speciation events.

Process-Like Modeling of Flank-Margin Caves: From Genesis to Burial Evolution

Abstract A major challenge in groundwater and petroleum modeling is how to represent the diagenesis effect sensu lato and its associated features (e.g., karst cavities, porosity and permeability characteristics). Both geometrical descriptions and genesis are necessary for modeling diagenetic features, because they allow the restitution of phenomenon in subsurface settings where they cannot be fully observed. This study focuses on flank-margin caves developed on carbonate islands (as in the case of the Bahamian islands). Over the last twenty years numerous measurements and observations have been carried out on Quaternary carbonate islands. These, together with reasonable hypotheses of genesis (fresh-water lens dissolution), make island karst an appropriate subject for developing concepts and modeling methods which can be then applied to other diagenetic features, such as reflux dolomitization and hydrothermal fluid effects. The speleogenesis of flank-margin caves was modeled following deterministic and stochastic methods to achieve a description of dissolution genesis. A fresh-water lens surface was built based on the topography of Long Island, Bahamas, and was then used to simulate virtual development of flank-margin caves at several formation phases, including uncertainty coefficients applied to both fresh-water-lens location and stability time by using 3D probability cubes. The cave simulations were compared with over sixty Bahamian cave surveys, in order to substantiate our modeling processes and results. Finally, the model was exposed to a cave collapse situation. The likelihood of preservation and the extent of the area affected were measured to provide an evaluation of the spatial distribution of associated petrophysical characteristics (e.g., porosity and permeability). The results reveal close resemblance and coherence between modeled and field data (including collapse features). Therefore the optimum method for restituting diagenetic features is by stochastic modeling actively driven by process concepts and most up-to-date methods.

Eogenetic karst, glacioeustatic cave pools and anchialine environments on Mallorca Island: a discussion of coastal speleogenesis

Eogenetic karst, glacioeustatic cave pools and anchialine environments on Mallorca Island: a discussion of coastal speleogenesis

Geopark as an answer to geoheritage conservation in Malaysia – The Langkawi Geopark case study

The interesting Palaeozoic geological history and amazing island karst landscapes are among the geological features of Langkawi, which have heritage value of national and regional significance. In order to conserve these geological heritage resources, the entire Langkawi Archipelago has been declared the Langkawi Geopark in May 2006. For Langkawi Geopark geoheritage conservation, 90 identified geoheritage sites were packaged into 3 geoforest parks, 3 geological monuments and several protected geosites. Several highly significant geoheritage sites were packaged into geopark trails or incorporated into existing nature tour trails. As for geotourism and public awareness, public friendly information panels and brochures were provided. The creation of Langkawi Geopark has paved a clearer path for the geoheritage conservation agenda in Malaysia. This achievement would not have materialized without serious commitment from various institutions, particularly the Malaysian Geological Heritage Group, Langkawi Development Authority, Department of Mineral and Geoscience and Forestry Department of Peninsular Malaysia. Langkawi Geopark is intended to be a model for sustainable development of geological heritage resources and to become a catalyst for future development of geoparks in this region.

The karstlands of Antigua, their land use and conservation

The northeastern 110 km2, or nearly 40%, of Antigua is underlain by impure limestones of the Oligocene‐aged Antigua Formation, on which has developed a subdued karst landscape consisting essentially of shallow enclosed depressions (dolines), intermittently active stream valleys and widely scattered residual hills. The dispersed dolines are broad, shallow and clustered, especially in the central and southeastern sections of the limestone belt, where they attain densities of 7/km2. The widely spaced residual hills attain heights of up to 40 m and localized densities of over 4/km2. Five main valley systems up to 6 km in length traverse the limestone in a broadly northeast direction, carrying both autogenic drainage from within the karst area and allogenic drainage from the non‐carbonate Central Plain. Karst and cave development has been constrained by the low purity of the limestones. Of the four types of carbonate islands identified within the Carbonate Island Karst Model, Antigua most closely resembles the Composite Island type. The karst has been much influenced by human activities, particularly agriculture and quarrying, and is now a focus of the burgeoning tourism industry. Virtually none of the karst is designated as protected areas, but several sites warrant protection, and several conservation strategies have been suggested.

Karren features in island karst: Guam, Mariana Islands

Karren features in island karst: Guam, Mariana Islands

Recent hydrogeologic study of the Vis island

The Vis Island belongs to the group of the Middle Dalmatian islands. It comprises an area of about 90.2 km2. Morphologically, three belts of highlands and two depressions with karst poljes are significant. The highest point on the island is Hum with 587 m a.s.l. the island’s water supply is organized from the water-supply station “Korita”, situated in the central part of island, in tectonically formed depression. There are two additional captured objects: the well K-l above the Komiža town and the spring “Pizdica”. The most important hydrogeological role on the island have two hydrogeological barriers, one in the Komiža Bay, completely made of impermeable igneous and clastic rocks, and another one, the recently recognized relative barrier in the area of Dračevo, Plisko and Velo polje. Since the island karst aquifer is in permanent dynamic relation with seawater, classical geologic, structural and hydrogeologic investigations have been performed with application of hydrogeochemical methods taking into account the natural Chemical tracer content of groundwater and its variations in different hydrologic and vegetation conditions. Precipitation regime is very unfavorable with regard to the recharging of island’s aquifer, because dry periods are usually very long. During the summer tourist season, when the number of inhabitants and fresh water consumption considerably increase, amounts of island’s groundwater suitable for water supply and irrigation rapidly decrease. Sometimes, insufficient quantity of fresh water on the Vis Island causes restrictions. Concerning the development of tourist potential and the present agricultural activities, summer lack of water is a serious restrictive factor. Some results of the performed hydrogeological study, important as a basis for island’s fresh water potential assessment, will be presented.

Recharge and aquifer response: Northern Guam Lens Aquifer, Guam, Mariana Islands

The Northern Guam Lens Aquifer is an island karst aquifer in uplifted young, highly conductive limestone. Calculations of recharge based on differences between daily rainfall and daily pan evaporation suggest that the maximum annual mass of water delivered to the freshwater lens is about 67% of mean annual rainfall. Hydrographs of daily well-level responses plotted against daily rainfall indicate that the rate at which water is delivered to the lens is a function of rainfall intensity and the relative saturation of the vadose zone. Together, these variables determine the degree to which stormwater is shunted into fast flow through preferred pathways that bypass the bedrock matrix, rather than percolating slowly through the bedrock matrix. Data from the 40-year interval from 1956 to 1995 show that some 17% of rainfall on northern Guam arrives in small amounts (<0.6 cm/day). Most of this light rainfall is probably lost to evapotranspiration. At least another 20% of total rainfall on Guam arrives at very high intensities (>5.0 cm/day), which tend to promote fast flow at the expense of percolation. Rapid recovery of the water table from rapid recharge suggests that the lens either takes such recharge into storage very rapidly, discharges it rapidly without taking it into storage, or some combination of both. Significant vadose buffering of recharge to the lens is indicated by the fact that simulations assuming that the recharge from precipitation received in any given month is transmitted to the lens during the same month consistently over-predict observed peak mean monthly water levels and under-predict the minima.

Données géomorphologiques sur la région de Fresh Creek, Ile Andros (Bahama)

A geomorphological study of the east coast of Andros (Fresh Creek area) shows the existence of a paleotopography represented by low-altitude hills (few metres). This paleotopography is protected by the presence of a calcitic Quaternary crust which covers Pleistocene calcarenite. In the western part of the area, there are long woody axes, oriented NE-SW, parallel to the channels of the creek. They end at two kilometres from the coast, along which is a second kind of lower hills, orthogonal to the first. The first axes can be interpreted as megaripples as seen at the present time on modern deposits (on the Great Bahama Bank) and fossilized by the upper crust. The second direction is made by accretion ripples along the coast. The surface of the Bahamian calcarenite has been studied. The Bahamian karst presents two topographical forms: “blue holes” like those outside the island, which are 60–80 m in diameter and both sparse and deep; and “washtub” dolines; these are numerous and shallow, and, from low altitude, exhibit a honeycombed aspect on the surface. This karstic topography with dolines and blue holes is also seen through the water of the Creek the hard bottom of which is covered only here and there with a few centimetres of sediments. Hence, there is a submerged karstic topography, made of the same elements as the aerial karst, but submerged by the Holocene transgression. The present karstic relief, in relation with the different eustatic levels of the Quaternary, has begun 120,000 years ago, according to the isotopic ages, and might be composed by different steps, difficult to show now, in the topography. The blue holes in the interior of the island of young and little evolved karst, were formed more by solution than by collapse of the karstic caves, because of the absence of a real river to drain the Andros shelf at the time of low sea levels. Blue holes of the inside of the island, as they are called, with submarine openings, have the same salinity as the water of the creek (17.5 g/l). The dolines with very low salinity (0.7 g/l to 3.8 g/l) are filled with stromatolites and charophytes, slowly forming sediments made up essentially of high-magnesian calcite. It seems that the Andros Island karst can be compared with that of the Yucatan, where there are round and deep open pits, called cenote, of which the Bahamian equivalent would be the blue holes which were drowned by the Holocene transgression.