National Speleological Society Convention
New Frontiers of Biospeleology
Organized by Megan Porter, University of Cincinnati
This project utilizes molecular population genetics data coupled with behavioral and geological information to elucidate patterns of speciation and relationships between populations in the cave-adapted plant hopper species complex Oliarus polyphemus. This species complex on the island of Hawaii occupies lava tubes in volcanically active regions of the island. As a result of its volcanic habitat, O. polyphemus populations have undergone repeated expansion, contraction, and isolation events during their relatively short history on Hawaii Island. Preliminary information has demonstrated significant differences in the mating calls of geographically close populations. While this behavioral information clearly demonstrates significant divergence between populations, it cannot distinguish the historical relationships of populations to one another. My work therefore uses genetic data to determine basic parameters of gene flow and to construct an intraspecific cladistic network in order to clarify the relationships of the populations. Genetic data (including sequence data and AFLP's) are being used to test the hypothesis that O. polyphemus is not limited to humanly accessible caves, but is distributed continuously throughout the millions of tiny voids in the lava substrate. This analysis will also help to better understand how habitat fragmentations have influenced the evolutionary history of O. polyphemus. Finally, this genetic information, when coupled with song data, can address basic issues of species status in the O. polyphemus complex. Because the identification of unique populations of O. polyphemus is likely to reflect similar patterns in other cave and surface organisms, conclusions of this study will identify crucial biological regions for conservation efforts.
The Cave Loaches of Thailand: Phylogenetic Relationships Among Populations and Species
Richard Borowsky Department of Biology New York University Washington Square, NY 10003
Five of the seven known cave fishes in Thailand are balitorid river loaches, a family common in the surface waters. The evolutionary relationships among species and genera in this family are unknown. Samples of the five troglobitic and 20 epigean Thai balitorids are under study using DNA fingerprint markers generated with AP-PCR techniques. AP-PCR data show genetic relatedness of populations and species and will be used to reconstruct the phylogenetic relationships of the Thai species and to study their population genetics. All eight cave populations studied (including species of Schistura, Noemacheilus and "Homaloptera") have lower genetic variation than populations of surface balitorids, eflecting their isolation and reduced effective population sizes. Inter-populational variation among four populations of Schisturaoedipus from Mae Hong Son was also studied. Although the four cave systems are isolated from one another, the populations are genetically similar, suggesting gene flow among populations, perhaps through surface waters. The waterfall climbing cave loach, Homaloptera thamicola is clearly different from H. zollingeri and H. smithi at the level of DNA fingerprint, and probably incorrectly placed in Homaloptera. In fact, it does not closely resemble any of the six genera examined. A new cave fish of uncertain relationship from Tham Phra Wang Daeng, near Phitsanoluk, was examined. It clusters more closely with Schistura rather than Noemacheilus.
Molecular Phylogenetic Characterization of Unusual Microbial Communities Associated with Corrosion Residues from Lechuguilla Cave
In order to more fully characterize the microbial community associated with corrosion residues (CRs), we are utilizing molecular phylogenetic techniques toavoid sampling biases introduced by enrichment cultures. Using techniques developed at Los Alamos National Laboratory for soil, we have extracted DNA from CR samples from Lechuguilla Cave. Polymerase chain reaction (PCR) amplification of extracted DNA with primers specific for small subunit ribosomal RNA genes indicates the presence of bacteria, archaea and eucarya in both CRs. We have begun to analyze a clone library generated from these PCR products. A restriction fragment length polymorphism (RFLP) analysis of 16 clones from this extracted DNA demonstrated that 14 of 16 clones were unique, revealing the existence of a diverse microbial community. Preliminary results from the phylogenetic analysis of the small-subunit ribosomal RNA (rRNA) gene from two clones showed that the nearest relatives of one clone are Crenarchaeota. The existence of this type of low-temperature Archaea has only been discovered in the last five years. Little is known about the metabolic properties of these Archaea due to the present inability to culture them. The other sequenced clone's closest relatives are gram positive bacteria. Both sequences are very dissimilar (less than 0.5 similarity, 0-1.0 scale) to any other known 16S rDNA sequences. Phylogenetic analyses will be discussed.
Cave Crickets at Mammoth Cave National Park: Source and Sink Population Dynamics
Congruent increases in population size among nine entrances from 1995 to1997 suggest that cave crickets inside MCNP do not exist as a metapopulation. Great differences in relative abundances of four size classes of crickets shows that there are both source and sink populations. In clear source entrances (3 out of 9 censused) small sizes are much more abundant than adults and so populations are increasing. But all other entrances (6 out of 9 censused) are sinks where adults out number or greatly out number small size classes. These populations are presumably maintained by immigration from sources. There was no correlation between population size and source entrances. The source entrances have some but not all of the following attributes: 1) close proximity of entrance roosts to reproductive areas; 2) ceiling pocket refuges from winter influxes of cold, dry air just inside the entrance; and 3) mesic summer microclimate with presumed better foraging opportunities in sinkholes and/or late successional forest outside the entrance.
Patterns of Subterranean Biodiversity in the Iberian Peninsula
The objectives of this project were (1) to create a data base which included taxonomic (order, family, genus, and species) and location (state and province) data for the more than 300 stygobites and troglobites of the Iberian Peninsula and (2) identify areas of high aquatic and terrestrial subterranean diversity ("hot spots") in order to facilitate protection strategies and further research. Areas of high terrestrial diversity were found in the Pyrennees and the northern states of Cantabria and Asturias. Areas of high aquatic diversity were found in the northern state of Cantabria and the island of Mallorca. Terrestrial diversity patterns reflect the extent of karst development, but aquatic diversity patterns also reflect areas of high diversity in small cavity subsurface habitats, such as the underflow of streams. An Excel file is available to interested individuals.
Primary Productivity Estimates from a Chemoautotrophic Microbial Community in Movile Cave, Romania
Since its inception, the Movile Cave Project has focused primarily on describing ecosystem energy and organic carbon sources. Previous research has documented microbial chemolithoautotrophy as the energetic base of the diverse and abundant invertebrate food web found in Movile Cave. Preliminary studies show that the microbial community contains sulfide-oxidizing, sulfate-reducing, methanotrophic, and heterotrophic bacteria. Current research is based on constructing an ecosystem energy budget by quantifying energy flow within the food web. As a first approximation of energy flow, primary productivity of the microbial community was examined. To estimate primary productivity in Movile Cave, time-course incorporation experiments were conducted using [14C] bicarbonate as a radiolabeled inorganic substrate. Preliminary results indicate that primary productivity in Movile Cave (approximately129.3 g C/m2/yr) is similar to published values for the open ocean and mesotrophic lakes, but is an order or magnitude greater than values estimated for deep-sea hydrothermal vents. Productivity estimates will be used in constructing a complete carbon budget for the Movile Cave microbial community. Continuing experiments focus on estimating microbial respiration and excretion.
Spatial and Temporal Patterns of Carbon, Nutrient and Microbial Transport in a Karst Aquifer
Aquifer physical structure and water flow patterns constrain energy input and distribution in karst groundwater ecosystems. Consequently, carbon availability and microbial biofilms may vary spatially by aquifer structural zone and temporally with hydrologic stage. To test this, we examined carbon and bacterial flux from aquifer input to output during two months in the Dorvan-Cleyzieu aquifer, France. Both months included low water followed by one or more floods. Dissolved organic carbon increased from input to output (p<0.01) but did not vary temporally (p>0.05). In contrast, microbial drift and activity (respiratory and hydrolytic) were not significantly different between structural zones (p>0.05), but changed significantly over time (p<0.001). In all zones, during initial floods total bacterial drift was high (86-130 x 103 bacteria/ml) then decreased during flood recession (24-32 x 103 bacteria/ml). Conversely, respiring bacterial drift was low at the peak of the first flood (5-17 x 103 bacteria/ml) then increased during flood recession (10-26 x 103bacteria/ml). Although initial floods after low water caused consistent changes in microbial drift, the drift patterns differed between structural zones during subsequent floods.
Biospeleology as the Basis of Groundwater Management
Current research using new techniques in microscopy and mass spectrometry have allowed an Ozark cave stream ecosystem (Cave Springs Cave, Arkansas) to be described fully for the first time, enabling better management practices for the recovery of the threatened Ozark cave fish (Amblyopsis rosae). The use of direct counts of microbial abundance by epifluourescence microscopy allows a good estimate to be made of total numbers of viable microbial cells in an aquatic ecosystem. Thus, the microbial community may be used as a bio-indicator of disturbance, especially in the form of organic loadings or intoxication. Furthermore, microbial biomass may be estimated from this technique, allowing a more complete carbon budget to be made or measurements of the bioavailability of organics present. The use of stable isotope assays allow a cave food web to be described completely, can determine which organic matter source (guano, agricultural waste, etc.) feeds the food web, and can identify pollution sources. Dye tracing, water-table contouring, photo-lineament studies, and other hydrogeologic methods have determined the recharge area for this cave stream, and the use of a geographical information system (GIS) has enabled a visual as well as statistical synthesis of the information relating to this spring complex. Once a groundwater ecosystem has been fully described, including energy and organic matter flux, trophic relationships, hydrogeologic characteristics, pollution threats, etc., it can be monitored and managed as an entire ecosystem.
CONTRIBUTED PAPERS
Corrosion Residues from Lechuguilla Cave: Cozy Home or Living Hell for Microbes?
Many ceiling and wall areas of Lechuguilla Cave (New Mexico) exhibit deposits called "corrosion residues'' (CRs) which appear to be breakdown products of several minerals. These CRs may be colored black, gray, pink, orange, red, or ocher and are distributed throughout the cave. Geologists have hypothesized that Lechuguilla's extensive CRs are the long-term result of upwelling corrosive air. Using enrichment cultures and Scanning Electron Microscopy, Cunningham and Northup discovered extensive bacterial and fungal communities in CRs. Preliminary evidence, including the presence of presumptive bacterial filaments in pits in the wall rock underlying CRs, implies that microorganisms may play an active role in corrosion of parent rock. Potentially, microorganisms could oxidize reduced compounds from the atmosphere or wall rock. The resulting acidity and other redox effects could consequently degrade the rock substrate. Our molecular phylogenetic studies are identifying the nature of this microbial community Energy Dispersive X-Ray (EDX) analyses of these residues and underlying wall rock reveals the presence of a heterogeneous makeup including the presence of iron and manganese oxides, as previously shown by Cunningham, along with phosphorus, clays, and sulfur. We have also identified rare earth elements, probably associated with apatite in the original limestone, and vanadium in some of the CRs. We are investigating the possible association of these potential inorganic energy sources with microorganisms present.
Distribution and Abundance of Cave Crickets in Mammoth Cave National Park Due to Weather
from 1995 to 1997 and Entrance Retrofitting in 1996
Five out of nine entrances were retrofitted in 1996 to stop air movement. Two of these entrances had existing steel doors that slowed air movement and two had antiquated open gates. All retrofitted entrances incorporated exit/entry tubes for animal movement in their designs. We censused 4 to 16 ten meter transects, depending on cave size and decline in animal abundance away from the entrance, 2-4 times per year in 1995 and1996 and bimonthly in 1996-1997. Except for one cave, where the positions and lengths of the exit tubes were not conducive to cave cricket use, there were no negative effects of retrofitting on animals other than pipistrelles. Air movement, but not winter temperature gradient, was also eliminated with the retrofits. There was a slow increase in cave cricket numbers from 1995 through 1997 correlated with short-term winter weather but not with average or extreme monthly temperatures. From 1995 to 1997 there were fewer and shorter periods with temperatures remaining below 5oC and more short respites of 2-3 days when temperatures remained above 10oC due to light rain. On these favorable nights, after many days or even weeks with no foraging, cave crickets exited in synchrony and foraged in large numbers. In summer there were no temperature constraints and cave crickets exited every night. Exiting was asynchronous with the usual 9-12 days between the summer foraging bouts.
Cave Crickets at Mammoth Cave National Park: You Are What You Eat
What do cave crickets eat? In aquaria with single food types, crickets do not gain weight on partially decomposed leaf litter with fungal hyphae, moss, lichens, leaves, or live earthworms and other litter organisms. Crickets gain 5-35 percent of crop empty live weight (CELW) on overripe fruit, fresh mushrooms, and deer fecal pellets. Crickets gain 70-120 percent of CELW on rotting mushrooms. But crickets gain 100-250 percent of CELW on both our 'high quality' canned cat food baits and 'low quality' wet cereal or metamucil mush that they readily locate in the field. The mystery is that high quality foods seem to be rare in the field whether we use extensive walking surveys of mushrooms and deer pellets or intensive 1 m2 searches for mouse and invertebrate feces or small carrion. Nonetheless crickets gain as much weight foraging on natural foods as they do when feeding on our artificial bait patches. Certainly crickets are better at finding quality items than we are using their acute olfactory senses. However the low Na/K ratios and low caloric density of their crop contents suggests they are not getting much carrion, even though we have seen them quickly locate and carry off horseflies killed at cave entrances.
Distribution and Abundance of Two Trogloxenes and a Troglophile in Mammoth Cave National Park
Using ten meter transects we censused heliomyzid flies (Amoebalaria defessa and A. brachypterna), camel crickets (Ceuthophilus stygius and C. gracilipes ), and spiders (Meta americana , Nesticus sp. and two others) in nine entrances at Mammoth Cave National Park from 1995-1997. Here we report winter vs. summer differences and show that entrance retrofitting did not affect the species compared to control entrances. All entrances had Nesticus or another similar sized spider but only five of nine entrances had Meta. For these five entrances, spider numbers and reproduction matched cave cricket abundance both among transects within a cave and among caves. No other species showed this correspondence. For camel crickets in winter, hibernating C. gracilipes and C. stygius had the same relative abundances among caves. These crickets tended to avoid the first transect and had similar distributions in subsequent transects. C. gracilipes were smaller and were solitary in tiny cracks whereas C. stygius were in small, loose aggregations and were larger in size. Only C. stygius increased from 1995 to 1997. In summer C. gracilipes was virtually absent inside entrances and C. stygius formed large, tight aggregations just inside the entrance. Both heliomyzids had the same relative abundance by transect within a cave and among caves though A. defessa was usually much more abundant. Both were randomly distributed at a microspatial scale. The range of heliomyzid abundance among caves was huge; the reasons are as enigmatic as is the role of these flies in the ecosystem.
Cave Crickets at Mammoth Cave National Park: Tests of Hypotheses of Sequential Constraints on Foraging
We generated hypotheses for control of foraging based on morphology and physiology, reproductive value sensu latu, and our modifications of central place foraging theory. A cricket 'decides' whether to forage outside based sequentially on crop emptiness, darkness, and weather. Continuous data from infrared cricket counters showed that there was progressively less winter exiting as temperatures dropped below 10oC. Even with temperatures above 10oC crickets did not exit with snow cover. In summer most crickets exited at temperatures above 10-20oC especially with light rain and/or wet forest litter. Once outside crickets decide where to forage, what to eat, and how much to eat. Post forage crickets with color coded bait in their crops were weighed to determine how much they had eaten as a function of distance from the cave entrance, caloric density of bait, and presumed predation risk. We presume that less weight gain reflects greater assessed risk. The strongest effects are that, compared to adult crickets, small crickets forage closer to the entrance and discriminate less between high and low caloric density baits. We had predicted this on the basis of size constraints, distance moved per step, and ability to detect remote food patches. Small crickets foraging behavior appeared to be unaffected by risk from weather and predation as we had predicted due to their low reproductive value. For adult crickets there were inconsistencies in amount eaten with distance, sex, and season even though we had predicted differences.
Phylogenetic Analysis of Bacterial Communities Isolated from Four Windows Cave: Are They Actinomycetes?
Silvery clusters of bacteria pepper the limestone walls of Four Windows Cave in El Malpais National Monument, New Mexico. In an effort to identify the types of bacteria in these colonies, we have utilized techniques developed at Los Alamos National Laboratory to extract DNA from colonies on wall rock. From this DNA, we utilized polymerase chain reaction (PCR) amplification and cloning to generate a library of 16S ribosomal RNA gene (rDNA) clones of the organisms present. Comparison of rDNA sequences from 30 of the clones with sequences available in the Ribosomal Database Project (RDP) revealed considerable genetic diversity. Many sequences were most closely related to those of actinomycetes, including Actinosynnema, Nocardia and Frankia spp., while some clones show relatedness to rDNAs of unknown organisms recovered from soils. Actinomycetes are a group of related bacteria that produce filaments during their development. These bacteria break down complex organic matter and thrive in environments where nutrients are sparse and conditions extreme. This description fits well the phenotype and habitat of this sample community. Further phylogenetic study of these communities will be discussed.
Preliminary Report on the Biology of Cueva de Villa Luz, Tabasco, Mexico
We participated in the January, 1998 Expedition to Cueva de Villa Luz in Tapihualapa, Tabasco, Mexico, organized by Jim Pisarowicz and Louise Hose. We present a preliminary overview of the biology of this interesting cave. Identifications of many species are still pending. We were initially attracted by the prospects of investigating a sulfur-based ecosystem, but the actual situation is much more complicated. Much of the cave is a stream passage, milky-white with sulfur. Many passages in the cave have very high levels of H2S, varying during this expedition from 0 to 57-127 ppm. Most passages were above 10ppm. The pH of the environment was generally more acidic than typically found in a limestone cave. Exceptionally low pHs were associated with"snottites" or microbial veils (pH 0.3-0.7), and in one area we identified a deposit of bat guano mixed with gypsum paste which had a pH of 0.0. Sulfate-reducing bacteria were present in very high numbers (105-106 +) in all sediments. Coliform bacteria survived in the mainstream passage, but were not detected in springs entering the cave. Microbial involvement is evident in the formation of white filaments in the cave stream and in microbial veils suspended from gypsum, possibly in association with webs of spiders or fungus gnats. There are also significant organic inputs through numerous skylights and from bat guano and other animals. Previous studies identified four types of phyllostomid bats in the caves. We also observed free-tail bats, probably Tadarida brasiliensis, as well as numerous vampire bats. Bats roosted in good air sections of passages, but flew freely though bad air passages. The most abundant organisms are the midges, Tendipes fulvipilus, which are the main prey for the molly, Poecilia sphaenops, which consumes both the aquatic larvae and adults. The fish are in turn preyed upon by a diving hemipteran (not identified). Both fish and midges are present in very high densities of hundreds to thousands of individuals in relatively small areas. The fish range from a cave-adapted form with reduced eyes and no pigmentation to a dark surface stream form with apparent intergradation between these two extremes. There was a very high density of predatory invertebrates throughout the cave, particularly spiders, fungus gnat larvae, and amblypygids. We found little evidence for terrestrial troglobites, with the possible exception of a spider and nematodes found in highly acidic vermiculations. We noted a surprising general lack of beetles, cave crickets and collembola. Studies to characterize the species collected are on-going, including molecular phylogenetic studies of DNA sequences from microbial communities in both terrestrial and aquatic environments. At the end of the expedition new passages were discovered in the cave. The new areas are typical limestone cave passages with good air; future studies of the types, distributions and abundance of animals in this part of the cave compared with the sulfur passages will be extremely interesting.
The Cave Fauna of Missouri
Missouri has at least 5600 caves containing more than 400 recorded species. Important populations of two cave crayfish and endangered Indiana bats, gray bats, and Ozark cave fish occur in the southern part of the state. Gardner systematically reported on the fauna of 436 caves and 10 springs in 1986. Craig, Hubricht, Lewis, Martin, Nicholas, Pflieger, Sutton, and others have added to the state fauna list. To date at least 39 troglobitic species have been identified, but many more probably will be found as more invertebrates are sampled. Accurate identification of species as troglophiles or troglobites depends on good biogeographic and taxonomic data. The declining pool of invertebrate taxonomists has made the basic task of identification and description more difficult.
Snapshots of Subterranean Biodiversity: 1888, 1960, and 1997
In 1888, A.S. Packard gave a complete list of known stygobites and troglobites, with their distribution. Brother Nicholas did the same in 1960, as did Hobbs and Culver in 1997. In 1888, 13 counties were reported as having at least one obligate cave species. In 1960, this number was 176, and in 1997 it was 630, approximately 20 per cent of all U.S. counties. Mean number of species, more counties with at least one species actually declined from a high of 6.7 in 1888 to 4.7 in 1997. Overall, the distribution became more skewed with time. An analysis of the 13 counties known to have an obligate subterranean species in 1888 declined to 3.8 in 1960 and rose to 11.6 in 1997. The original decline was the result of Packard’s tendency to believe every cave inhabitant was cave-limited. Nowhere was this more pronounced than in Mammoth Cave.
The Illinois Cave Amphipod, Gammarus acherondytes, Status and Concerns
Gammarus acherondytes Hubricht and Makin is a rare troglobite endemic to subterranean streams in Illinois' Salem Plateau. It previously was recorded from five caves in Monroe and St. Clair counties, Illinois. An examination of 164 Illinois caves (1986-1995) added one new record, a single specimen from Madonnaville Cave collected in 1986. These recent surveys documented a large population of G. acherondytes in Illinois Caverns, a moderate population in Fogelpole Cave, and a small population in Kreuger-Dry Run Cave. Pautler Cave, a previously known locality, has been bulldozed shut by the landowner. Gammarus acherondytes has not been collected in Stemler Cave since 1965, and none were collected in Madonnaville Cave in 1995. Groundwater of this karst area has deteriorated in quality over the last 10 years. This is correlated with increased rural development, use of aeration systems in private septic treatment, and agricultural chemical use.
Through the collaborative efforts of a variety of organizations, a multifaceted approach to karst problems and management in this area provides some hope that G. acherondytes may eventually receive protection sufficient to allow humans and the amphipod to coexist. Current efforts focus on a variety of issues including: 1) educational programs, 2) dye tracing, 3) changes in local karst regulations, 4) formation of the Mississippi Karst Resource Planning Committee and the Sinkhole Plain Ecosystem Partnership, 5) well monitoring, 6) geological investigations, 7)establishment of nature preserves and other protected lands, 8) proposed listing of this amphipod as federally endangered, and 9) further biospeleological studies.
The extent and nature of the diverse cave invertebrates found within the confines of Sequoia and Kings Canyon National Parks are only now coming to light. Limited biological inventory work has revealed as many as 16 troglobitic species endemic to particular caves or even particular rooms in a single cave. A total of 38 apparently new species and one new genus of invertebrates have been recognized in Park caves. These discoveries include spiders, harvestmen, isopods, millipedes, crickets, mites, hymenopterans, diplurans, collembolans, beetles and pseudoscorpions. While many of these animals have been collected, few have been named to species. In an attempt to document these animals and in order to further recognition of them in monitoring plots, Sequoia and Kings Canyon are attempting to photograph most or all of these animals.
Taxonomy and Systematics of Cave Organisms in the 21st Century: A Look Ahead
Organized by David Culver, American University, Washington, D.C.
The polydesmoid genus, Speodesmus, which is troglobitic, contains four described species from Texas, New Mexico, and Colorado. At least six new species in two species groups are known from Central Texas, and new populations have been found in West Texas and Utah. Numerous genera and species of cavernicolous rhagidiids are known from caves in the USA and Mexico. Some of the populations are relicts of arctic and boreal litter-dwelling ancestors, but there are unexplained gaps in Texas and other cave areas. Other arthropod groups are inexplicably scarce or absent from regional cave faunas in the USA; two examples are rhaphidophorid crickets in California and carabid beetles in Missouri.
Databases for Cave Biology North of Mexico
The status of an ongoing project to record basic bio-information for the cave faunas of the U.S. and Canada for a CD ROM, and webpage are reviewed. The reasons for the level of security and of the specificity of biogeographic and taxonomic data are explained. The data recorded to date, such as the rate of new citations and species descriptions and the tracking of rare species by state natural heritage programs, state speleological surveys and federal and state agencies reveals gaps in knowledge of certain karst areas and taxa.
Species and Speciation in Cave Animals
Animals with long evolutionary histories in caves share a morphological syndrome termed troglomorphy. The troglomorphic pattern includes reduced or lost features, such as eyes and pigmentation, and elaborated features, most notably enhanced extra-optic sensory structures and elongated appendages. The fact that the troglomorphic pattern is shared by distantly related taxa (e. g., cave-dwelling vertebrates and invertebrates) and by similar but geographically distant taxa (e. g., cave-dwelling carabid beetles of Europe and North America) suggests that troglomorphy is a consequence of a considerable amount of parallel and convergent evolution. Convergence and parallelism provide difficulties for systematists because features which have evolved in this manner do not reflect shared evolutionary history. In fact, phylogenetic studies using biochemical and molecular characters have shown that populations presumed to be conspecific on the basis of morphological features are actually much more distantly related. This raises the possibility that convergence and parallelism may be important processes even on very local geographic scales, and that many presumptive cave species may in fact be species complexes, despite being morphologically very similar.
Genetic data on several cave inhabiting species, including the cave fish Typhlichthys subterraneus, the amphipod Gammarus minus and several species of trechine carabid beetles indicate substantial differentiation among populations deemed conspecific on morphological grounds. These data clearly indicate lack of gene flow among these populations and are at least consistent with the view that the evolution of troglomorphic features within these supposed species may be polyphyletic. These results have implications for understanding the phylogenetic history of cave-dwelling organisms as well as for understanding what an evolutionary unit is in the case of cavernicoles. Among other things, these results suggest that isolation in and adaptation to the subterranean environment may be more frequent than has been previously thought.
Progress in Cave Collembolan Taxonomy and Biogeography in the Next 30 Years
Cave biogeography has a great need for more knowledge concerning the phylogeny of cave Collembola and the relationship between this and the microgeographic distribution of species. We need information concerning the relationships between specific nucleic acid sequences and the adaptive features seen in troglomorphy. Collembolan taxonomy has a shortage of funding for taxonomists outside Europe. Even within Europe, some taxonomists are unable to get employment or funds for research. A major problem, which must be settled, is the nature of the cavernicole species.
Even if at some time in the future specimens captured in the field may be quickly or even immediately analyzed using molecular techniques, and then referred to a computer base system to see what species or population they most closely resemble in DNA or protein structure, this would only be useful if we could show the relationship between such an analysis and the evolutionarily significant morphology, physiology and behavior, i.e., troglomorphy. At present we are still a long way from this.
Molecular studies have been little used with small cave organisms, particularly arthropods such as Collembola. They have not dealt with the questions of the genetic basis of troglomorphic features and the genetic relationships among widely dispersed troglophile and troglobite species. Advances in technology should make these problems more amenable to analysis, but the question of available funding, and thus research interest, remain unresolved.
What will biospeleological Collembola taxonomy be like in the next 30 years? Various scenarios come to mind and I shall present two extremes. 1) General funding for taxonomy increases as the biological community realizes that this is the essential first step for any ecological or evolutionary analysis. This combined with relatively cheap and easily used molecular techniques, as well as increased facility in using computer scanning techniques for taxonomic analysis, results in a melding of genetic, morphological and behavioral information to develop a new sound and widely accepted picture of cave species as groups of evolutionarily and genetically united taxa. The result is a very good picture of cave organisms, widely used in evolutionary and ecological studies. 2) Funding for taxonomy continues to focus more and more on genetic studies. Eventually this leads to a relatively static or diminishing knowledge of alpha and beta taxonomy of many groups such as Collembola. At the same time there is a much greater facility for genetic analyses and funding for such studies. The inability to match this information with troglomorphic features leads to a characterization of cave populations solely on the basis of genetic structure and the move towards abandoning of binomial nomenclature in favor of characterization of populations and eventually species as clusters of genetic formulae, stored and analyzed in computers. The result is a diminished interest in cave microarthropods such as Collembola as model systems for evolutionary and ecological study. Obviously various intermediates as well as entirely different scenarios are possible.
Mapping Biodiversity of Cave Organisms
Protection and education about cave organisms can best come about with a detailed understanding of their distribution. An ongoing project, in conjunction with The Nature Conservancy, aims to provide a list of cave-limited species, by county. Data on more than 1000 species and subspecies are included in the database. Analysis of patterns suggests that the biggest gap in our knowledge is for non-cave subsurface habitats, especially small-cavity habitats such as the underflow of rivers. These species comprise less than 10 per cent of the aquatic fauna. In Europe, they are often the majority. Most geographic areas are well covered, but data for the Ozarks, especially Arkansas, is not as complete as elsewhere. While counties are not a natural boundary, most data are listed by county, rather than by drainage basin. Lists by cave, while obviously more detailed, are more difficult to map. Several GIS maps of biodiversity will be displayed.
The Subterranean Fauna of Southeast Asia: Taxonomic and Biogeographic issues
Southeast Asia has the most extensive and the most diversified karst of the tropics. In the last two decades, evidence has accumulated that a rich fauna inhabited the caves of this region. I describe here its most remarkable features:
The Future for Cave Fishes
The first cave dwelling fish was discovered in the 1820s and the first named species(Amblyopsis spelaea) was described from Mammoth Cave in 1842. Since then cave fishes have been discovered in 27 countries world wide and there are now 79 described species. At the turn of the millennium there will be roughly 100 known cave fishes. What will happen to these in the next few decades and how might these numbers change? It seems certain that the number of known species will increase. In 1960 there were 27 species, 1970 35, 1980 39, and1990 59 and in 1998 79. If this rate of discovery remains constant there will be 85 species by 2000, 125 by 2010 and 200 by 2020. At the same time it is possible that known species will become extinct. Three species(Clarias cavernicola, Namibia; Speoplatyrhinus poulsoni, USA; Glossogobius ankaranensis, Madagascar) are assessed as critically endangered by IUCN. Two are assessed as endangered (Prietella phreatophila and Ophisternon infernale, both in Mexico) and no less than 46 as vulnerable. This is 63% of all known species. One of the critical needs of the next few years therefore is for conservation assessments so that conservation effort is directed to the right places. A central plank of this must be accurate population assessment. A second will be an examination of the molecular genetics of demes. Sbordoni et al., working on Somali species, Noltie et al. on Amblyopsids, and Borowsky on Mexican and Thai animals, have all shown that morphological species are in fact several to many isolated populations all of which may merit specific identity. If this assessment is accepted it makes the conservation task more difficult if we wish to preserve the genotypes of these populations as well as the phenotype. Over 50% of all known species are from only five countries (China, Mexico, Brazil, USA and Thailand) and in all of these human population pressure will continue to increase. In summary the next few decades will see a large increase in the number of described morphological species (and perhaps many more "molecular" species).One or two species may well become extinct and a great many more will suffer declines in population or in habitat quality. Ideally we would like to protect many or all of these in situ but it does not seem realistic that we can achieve this. Perhaps the most critical need in the next few decades is to start captive breeding of as many as we can. This is a daunting task.