Search KARSTBASE:
Search in KarstBase
Using a comparative phylogeographic approach and different independent molecular clocks we propose a timescale for the evolution of troglobionts in the Dinaric Karst that is relatively consistent over a wide taxonomic range. Keystone events seem to belong to two age classes. (1) Major splits within holodinaric taxa are from the mid-Miocene. They present the potential upper limit for the age of cave invasions. (2) Regional differentiation, including speciation, which can at least in part be associated with a subterranean phase, took place from early Pliocene to mid-Pleistocene. We suggest two to five million years as the time when most of the analyzed lineages started invading the Dinaric Karst underground.
Terrestrial animals in subterranean habitats are often classified according to their degree of morphological or ecological specialization to the subterranean environment. The commonly held view is that, as distance into a cave increases, the frequency of morphologically specialized, i.e., troglomorphic, species or ecological specialization will increase. We tested this hypothesis for the fauna in 54 caves in Slovenia–the classical land for subterranean biology. We found that there exist two ecologically well separated terrestrial subsurface faunas: one shallow and one deep. 1) The shallow subterranean fauna, adapted to the terrestrial shallow subterranean habitats (SSHs) in the upper 10 m of subsurface strata, is most diverse. It consists of randomly distributed non-troglobionts and a major group of troglobionts adapted to the soil root zone. 2) The deep subterranean fauna is represented by a minor group of troglobionts, adapted to caves. Troglobionts are strictly divided between the two faunas. There is strong evidence that in karstic ecosystems with deep-rooted vegetation this might be a global pattern, or that in these locations only the shallow subterranean fauna exist.
Terrestrial animals in subterranean habitats are often classified according to their degree of morphological or ecological specialization to the subterranean environment. The commonly held view is that, as distance into a cave increases, the frequency of morphologically specialized, i.e., troglomorphic, species or ecological specialization will increase. We tested this hypothesis for the fauna in 54 caves in Slovenia–the classical land for subterranean biology. We found that there exist two ecologically well separated terrestrial subsurface faunas: one shallow and one deep. 1) The shallow subterranean fauna, adapted to the terrestrial shallow subterranean habitats (SSHs) in the upper 10 m of subsurface strata, is most diverse. It consists of randomly distributed non-troglobionts and a major group of troglobionts adapted to the soil root zone. 2) The deep subterranean fauna is represented by a minor group of troglobionts, adapted to caves. Troglobionts are strictly divided between the two faunas. There is strong evidence that in karstic ecosystems with deep-rooted vegetation this might be a global pattern, or that in these locations only the shallow subterranean fauna exist.
Subsurface biota extends over a wide variety of habitats that can be spatially interconnected. The largest communities of this subsurface biota inhabit cavities and are well known mainly in caves where biologists are able to have access. Data about deep subterranean communities and arthropods living under one thousand meters was unknown. An expedition to world’s deepest cave, Krubera-Voronja in Western Caucasus, revealed an interesting subterranean community, living below 2000 meters and represented by more than 12 species of arthropods, including several new species for science. This deep cave biota is composed of troglobionts and also epigean species, that can penetrate until -2140 m. Deep subterranean ecosystems should not be seen only as an evolu- tionary dead end towards the troglomorphic syndrome, but also as a shelter for epigean species populations, especially during long periods of time when surface conditions are severe for their survival. Most of the subsurface biota depends on allochthonous sources of organic carbon coming from: water percolating from the surface, sinking streams that enter caves, and activities of animals mov- ing in and out of caves. The biocoenosis and the vertical distribution of invertebrate fauna of Krubera-Voronja are provided, from its entrance to the remarkable depth of 2140 meters, including the discovery of world’s deepest dwelling arthropod.
The Judbarra / Gregory Karst Region is situated in the Judbarra / Gregory National Park, west of Timber Creek, Northern Territory. Several large joint controlled maze caves occur within the area, developed within and below a prominent dolomitic layer (the Supplejack Member). The caves are predominantly shallow in depth (< 15 m below the surface) but are occasionally developed deeper as multi-level systems, reaching the aquifer. Two biological surveys from the largest caves have revealed 56 morphospecies from 43 families, 19 orders, and 7 classes. All collecting was undertaken in the northern dry season (April to September) and consisted predominantly of opportunistic collecting. The diversity of invertebrates collected from the Judbarra / Gregory karst comprised non-troglobionts (48 species, 86%), troglobionts (5 species, 9%), stygobionts (2 species, 3%), and trogloxenes (1 species, 2%). Five of the species are considered to be potential troglobionts, and two potential stygobionts as indicated by troglomorphisms such as elongate appendages and reduced or absent eyes. The five troglobiont species are an isopod (Platyarthridae: Trichorhina sp.), a scorpion (Buthidae: Lychas? sp. nov.), a pseudoscorpion (Geogarypidae: Geogarypus sp. nov.), a millipede (Polydesmida: sp.), and a planthopper (Meenoplidae: sp.). The two stygobiont species are a hydrobiid snail (Hydrobiidae: sp.), and an amphipod (Amphipoda: sp.). The troglobiont scorpion is only the second collected from a cave environment from continental Australia.
This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.
The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.
Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.
Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.
In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.
Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.
In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.
The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.
The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.
Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.
Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.
In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.
Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.
In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.
The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.
This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.
The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.
Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.
Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.
In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.
Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.
In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.
The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.
The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.
Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.
Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.
In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.
Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.
In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.
The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.
A bibliographic analysis of the hypogean biological studies in Portugal is made, compiling 138 publications related to the subterranean invertebrate fauna, since its begining in 1870 until November 2012.
A catalogue of hypogean endemic taxa is provided, listing 27 troglobionts and 63 stygobionts, described to be obligate hypogean and endemic from mainland Portugal (Macaronesian archipelagos excluded).
The first impetus on troglobiont studies was provided by the prospections of Barros Machado during 1940’s and by an expedition of Lindberg in the spring of 1961; and the major information about stygobiont species was provided by the former Instituto de Zoologia “Dr. Augusto Nobre” from Porto University.
Seasonality in surface weather results in seasonal temperature and humidity changes in caves. Ecological and physiological differences among trogloxenes, troglophiles, and troglobionts result in species-dependent responses to this variability. To investigate these responses, we conducted five biological inventories in a marble cave in the Sierra Nevada Range, California, USA between May and December 2010. The cave was divided into six quadrats and temperature was continuously logged in each (humidity was logged at the entrance and in the deep cave). With increasing distance from the entrance, temperature changes were increasingly attenuated and lagged relative to surface temperature. Linear regressions were created to determine the relationship between measured environmental variables and diversity for cavernicoles (troglobionts and troglophiles) and trogloxenes cave– wide and in the transition zone. Diversity for cavernicoles and trogloxenes peaked in the entrance and deep cave zones, respectively. Quadrat, date, 2-week antecedent temperature average, 2-week antecedent temperature range, and trogloxene abundance explained 76% of cavernicole diversity variability. Quadrat explained 55% of trogloxene diversity variability. In the transition zone, trogloxene abundance explained 26% of cavernicole variability and 2-week antecedent temperature and 2-week antecedent temperature range explained 40% of trogloxene variability. In the transition zone, trogloxene diversity was inversely related to 2-week antecedent temperature average and 2-week antecedent temperature range, suggesting that species were moving into the transition zone when temperature was most stable. In a CCA of cavernicoles distribution data and environmental variables, 35% of variation in species-specific distributions was attributable to quadrat, and non-significant percentages were explained by date and environmental variables. Differences in assemblage structure among quadrats were largely due to differences between distributions of trogloxenes and cavernicoles, but responses varied among species. Differences are likely due to ecological niche width, physiological constraints, and competition.
Millipedes play an important role in the decomposition of organic matter in the subterranean environment. Despite the existence of several cave-adapted species of millipedes in adjacent geographic areas, their study has been largely ignored in Portugal. Over the last decade, intense fieldwork in caves of the mainland and the island of Madeira has provided new data about the distribution and diversity of millipedes. A review of millipedes from caves of Portugal is presented, listing fourteen species belonging to eight families, among which six species are considered troglobionts. The distribution of millipedes in caves of Portugal is discussed and compared with the troglobiont biodiversity in the overall Iberian Peninsula and the Macaronesian archipelagos.
Most organisms are able to survive shorter or longer exposure to sub-zero temperatures. Hypothetically, trogloxenes characterized as not adapted, and troglophiles as not completely adapted to thermally stable subterranean environment, have retained or partially retained their ability to withstand freezing, while most troglobionts have not. We tested this hypothesis experimentally on 37 species inhabiting caves in Slovenia, analyzing their lower lethal temperatures in summer and winter, or for one season, if the species was not present in caves during both seasons. Specimens were exposed for 12 hrs to 1°C-stepwise descending temperatures with 48 hr breaks. In general, the resistance to freezing was in agreement with the hypothesis, decreasing from trogloxenes over troglophiles to troglobionts. However, weak resistance was preserved in nearly all troglobionts, which responded in two ways. One group, withstanding freezing to a limited degree, and increasing freezing tolerance in winter, belong to the troglobionts inhabiting the superficial subterranean habitats. The other group, which equally withstand freezing in summer and winter, inhabit deep subterranean or other thermally buffered subterranean habitats. Data on cold resistance can thus serve as an efficient additional measure of adaptation to particular hypogean environments.
Karst environments can be grouped into three broad categories, based on their vertical position in the landscape. There are surface habitats, ones exposed to light; there are shallow subterranean (aphotic) habitats oft en with small to intermediate sized spaces; there are deep subterranean habitats (caves) with large sized spaces. Faunal records are most complete for caves, and on a global basis, more than 10,000 species are limited to this habitat. Hundreds of other species, especially bats, depend on caves for some part of their life cycle. A large, but most unknown number of species are limited to shallow subterranean habitats in karst, such as epikarst and the milieu souterrain superficiel. Species in both these categories of habitats typically show a number of morphological adaptations for life in darkness, including loss of eyes and pigment, and elaboration of extra-optic sensory structures. Surface habitats, such as sinkholes, karst springs, thin soils, and rock faces, are habitats, but not always recognized as karst habitats. Both aphotic karst habitats and twilight habitats (such as open air pits) may serve as important temporary refuges for organisms avoiding temperature extremes on the surface.