Cave Entrance Research Articles

The diversity and morphology of the genus Luticola D.G.Mann (Bacillariophyta) from subaerial biofilms of caves in Serbia

Research of cave-dwelling diatoms is lacking. In these extreme environments, diatoms are restricted to illuminated zones, and are found at the entrance zone and in the lampenflora community. However, the number of identified species is constantly increasing, and new species are being discovered. The genus Luticola is one of the most widely studied genera worldwide and many representatives are characterized as aerophilous and are found in terrestrial habitats. For the first time, Luticola species identified from phototrophic subaerial biofilms of 10 caves in Serbia (cave entrances and lampenflora) based on detailed light microscopy (LM) and scanning electron microscopy (SEM) observations were summarized and discussed. In total 11 representatives of the genus were identified at the species level, and morphological features of Luticola acidoclinata, L. angusta, L. frequentissima, L. dismutica, L. nivalis, L. triundulata, and L. quinquenodis were characterized in detail. For Luticola angusta, electron microscopy images are shown for the first time. Additionally, four new taxa (L. angusta, L. frequentissima, L. kopanjae, and L. poulickovae) were recorded for the diatom flora of Serbia. The study fills an important gap regarding the occurrence and characteristics of Luticola representatives in subaerial habitats.

Biodiversity of a temperate karst landscape-ice cave collapse doline supports high α-diversity of the soil mesofauna.

Caves represent a specific environment with a special microclimate and fauna adapted to it. However, we have still a restricted knowledge on soil fauna communities in an environments with a marked microclimate gradient at the interface between cave and surface habitats. In the present study, we investigated the community patterns of dominant soil microarthropod group, oribatid mites, and their relationship to environmental factors across the microclimate gradient along a transect with seven study sites from cold and wet cave entrance zone to warm and drier deciduous forest. The cold and wet sites showed low oribatid abundances and a high spatial clustering of individuals in comparison to the warm sites. The oribatid mites showed significantly higher abundance and species richness at warm forest sites. Indicator species analysis indicated specific cold-tolerant species that dominated at cold sites of the gradient, but which were absent at the warmest sites. Variance analysis clarified that community composition at sites were significantly driven by environmental factors: temperature, soil moisture, pH and C/N ratio. The study underlines the importance of ice cave entrances as sources of high α-diversity of soil mesofauna and thus the conservation priority of these valuable habitats.

Baseline survey of environmental parameters, radiation, and drip water hydrochemistry in Niah Caves (Sarawak, Malaysia)

Relict caves in fenglin karst may typically have numerous entrances and openings. Hence, they host a variety of environments in which parameters such as light, airflow, humidity, and temperature may vary significantly over short distances. Similarly, drip water hydrochemistry, including isotopic values, may vary due to different contributions of various sources and residence time in the karst. This study investigated environmental parameters, including radiation, using hand-held instruments, along a transect within several major caves in the Niah karst of Sarawak (Malaysia). This has led to a baseline data set which showed an inverse relationship between humidity and temperature, gamma radiation levels that are about 25% of that in surrounding non-karst region, and high percentages of twilight zones in the studied caves. Airflow was found to be variable, with high values of 530 m3/s in Painted Cave and 122 m2/s in parts of Gan Kira passage, with flow towards the southeast at the time of the study. The hydrochemistry of the drip water and surface water was also analyzed and found to be dominantly Ca–Mg–Cl water type which indicates dissolution of minerals through water–rock interaction. In addition, the cave environment, particularly air temperature, humidity, and ventilation, also influences the drip water composition and isotopic values. Three different origins (precipitation, evaporation, and paleo-recharge) of drip water have been identified through the δ18O-δ2H diagram. Enriched isotopic values were observed in the cave entrance due to increased evaporation caused by lower humidity and higher air temperature. Factor analysis identifies the key geochemical processes responsible for the drip water chemistry. The outcome of this study provides the first baseline environmental data for the Niah caves, which could support future initiatives for sustainable management of this famous archeological site in southeast Asia.

A study on the diversity of phlebotomine sand flies (Diptera, Psychodidae) in karstic limestone areas in Vientiane Province, Laos, with a description of two new species of Sergentomyia França and & Parrot

BackgroundSoutheast Asia is well known as a hotspot of biodiversity. However, very little is known about cave-dwelling hematophagous insects that are medically important. Taxonomic knowledge and ecology of phlebotomine sand flies are very poorly studied in Laos, as well as in other countries in the region. Herein, we report species diversity data and some notes on the ecology of the detected species from these karstic limestone areas of Laos.MethodsPhlebotomine sand flies were collected using Centers for Disease Control and Prevention (CDC) light traps from limestone cave locations in three districts of Vientiane Province, Laos. Both morphological and molecular techniques were used for sand fly identification. Species diversity and abundance were analyzed according to sites, locations, collection seasons, and trapping positions.ResultsA total of 6564 sand flies, of which 5038 were females and 1526 were males, were morphologically identified into 20 species belonging to five genera (Chinius, Idiophlebotomus, Phlebotomus, Sergentomyia, and Grassomyia). The most abundant species were Chinius eunicegalatiae, Phlebotomus stantoni, Sergentomyia hivernus, Se. siamensis, and Idiophlebotomus longiforceps. Cytochrome b analysis results supported the morphological identification and revealed that Se. siamensis was separated from other members of the Se. barraudi group. Two new species, Se. dvoraki n. sp. and Se. marolii n. sp., were described. Sand fly density was generally high except in a cave in Vangvieng, with species richness ranging from 14 to 18 across different caves. Outside caves had higher species richness (R = 20) and diversity (H = 2.50) than cave entrances (R = 18, H = 2.41) and interiors (R = 16, H = 2.13). Seasonal variations showed high sand fly density in Feung and Hinheup during both dry and rainy seasons, while Vangvieng had a notable decrease in density during the dry season (D = 6.29).ConclusionsThis study revealed that the diversity of phlebotomine sand fly fauna in Laos, particularly in karstic limestone areas, is greater than previously known. However, the taxonomic status of many species in Laos, as well as Southeast Asia, still needs more in-depth study using both morphological characters and molecular methods. Many species could be found from inside, at the entrance, and outside of caves, indicating a wide range of host-seeking behavior or possible natural breeding in the karstic cave areas.Graphical abstract

Flourishing in Darkness: Protist Communities of Water Sites in Shulgan-Tash Cave (Southern Urals, Russia)

Karst caves, formed by the erosion of soluble carbonate rocks, provide unique ecosystems characterized by stable temperatures and high humidity. These conditions support diverse microbial communities, including wall microbial fouling, aquatic biofilms, and planktonic communities. This study discloses the taxonomic diversity of protists in aquatic biotopes of Shulgan-Tash Cave, a culturally significant site and popular tourist destination, by 18S rRNA gene metabarcoding. Our findings reveal the rich protist communities in the cave’s aquatic biotopes, with the highest diversity observed in Blue Lake at the cave entrance. In contrast, Distant Lake in the depth of the cave was inhabited by specific communities of plankton, mats, and pool fingers, which exhibited lower richness and evenness, and were adapted to extreme conditions (cold, darkness, and limited nutrients). High-rank taxa including Opisthokonta, Stramenopiles, and Rhizaria dominated all biotopes, aligning with observations from other subterranean environments. Specific communities of biotopes inside the cave featured distinct dominant taxa: amoeboid stramenopile (Synchromophyceae) and flagellates (Choanoflagellatea and Sandona) in mats; flagellates (Choanoflagellatea, Bicoecaceae, Ancyromonadida) and amoeboid protists (Filasterea) in pool fingers; flagellates (Ochromonadales, Glissomonadida, Synchromophyceae), fungi-like protists (Peronosporomycetes), and fungi (Ustilaginomycotina) in plankton. The specificity of the communities was supported by LEfSe analysis, which revealed enriched or differentially abundant protist taxa in each type of biotope. The predominance of Choanoflagellatea in the communities of cave mats and pool fingers, as well as the predominance of Synchromophyceae in the cave mats, appears to be a unique feature of Shulgan-Tash Cave. The cold-tolerant yeast Malassezia recorded in other caves was present in both plankton and biofilm communities, suggesting its resilience to low temperatures. However, no potentially harmful fungi were detected, positioning this research as a baseline for future monitoring. Our results emphasize the need for ongoing surveillance and conservation efforts to protect the fragile ecosystems of Shulgan-Tash Cave from human-induced disturbances and microbial invasions.

The use of the malacofaunistic method for reconstructing the palaeoecological conditions of the late late pleistocene to holocene based on material from the Tetyukhinskaya Cave Site, Southern Far East, Russia

Results of the study of terrestrial mollusc shells from the unconsolidated deposits of the Tetyukhinskaya Cave, Dalnegorsk, Primorsky Krai, Russia are presented. Brief species descriptions of the molluscs and their images complete the scarce information on the fossil Quaternary mollusc fauna of the region. With the help of malacological analysis, characteristic zones and malacological complexes were identified, which were used as indicators of the habitats near the cave entrance and in the adjacent territory. The data concerning the palaeoecological conditions of individual mollusc species confirm the development of broad-leaved and mixed forests, alongside open meadows with herbage vegetation in the region near the cave, towards the end of the Late Pleistocene and in the Holocene.

Biology and ecology of a deep cave nesting spider wasp, Ageniella evansi Townes, (Hymenoptera: Pompilidae), in Arizona

ABSTRACT Cavernicolous populations of the spider wasp Ageniella evansi Townes, 1957 (Hymenoptera: Pompilidae) nest deep within limestone caves at Colossal Cave Mountain Park near Tucson, Arizona, USA. These remarkable populations are the only truly cavernicolous pompilid wasps currently known. As many as 79 females were documented nesting simultaneously within Arkenstone Cave. The facts that the wasps do not nest near cave entrances but only deep within the interior of the caves, are philopatric to each occupied cave and have been present each year for decades confirm their cavernicolous behaviour as subtroglophiles. Studies conducted for over 30 years revealed many insights into the behaviour of these wasps in addition to their nesting deep within limestone caves, including: intraspecific and interspecific competition, plasticity in host selection, precision solar navigation, evidence that some form of communal nesting may be present and behaviour suggestive of rudimentary cognition in the species. This study demonstrates the importance of assessing all animals found in caves as potential ecological elements and not focusing solely on exotic troglobiotic species.

The first emerging records of a dragonfly in the dark zone of subterranean ecosystems: Exuviae and newly emerged adults of Hyrcanian Goldenring, Cordulegaster vanbrinkae in Danial Cave, northern Iran.

Riverine caves are special habitats that are home to many aquatic and terrestrial species. Some Odonata species and their emerging are recorded at the entrance and in the twilight zones of subterranean habitats around the world. However, the emergence of any Odonata species has not been recorded in the dark zones of caves or other subterranean habitats. We report the first evidence of the emerging of the Hyrcanian Goldenring, Cordulegaster vanbrinkae Lohmann, 1993, as an endemic species of the Hyrcanian biogeographical region, in the dark zone of Danial Cave, in the World Heritage-listed Hyrcanian Forests, northern Iran. During 2020-2023, three newly emerged and three exuviae of the species were recorded in the entrance zone (25 m) and the dark zone of the cave (200-280 m). The main hypothesis of the study is the entry and exit of adults from the cave entrance. However, we still do not know if the newly emerged will leave the cave or not. We still need more study on the biology and ecology of the species inside and around the cave. Danial Cave, with its high biodiversity, is one of the most important caves in the Middle East, and is urgently in need of conservation as a national natural monument.

Distribution pattern and driving factors of mite communities in karst cave ecosystems.

Mites are among the most abundant invertebrates in subsurface ecosystems, and their community assemblages and distributions are often significantly influenced by the diversity of habitat resources. The cave ecosystem encompasses drastic changes in nonbiological factors, such as changes in lighting conditions from bright to extraordinarily dark and habitat gradients of surface plant resources from abundant to scarce or even disappearing, providing an ideal unique environment for evaluating the assembly mechanism of soil animal communities. Nevertheless, there still needs to be a sufficient understanding of the biodiversity patterns and drivers of mite communities across environmental gradients in karst caves. We conducted a comprehensive survey on the composition and diversity of soil mites in three photometric zones (dark, twilight, and light) of a typical karst cave and its adjoining extractive environments (forest scrub and farmland). Our research aimed to investigate the ecological relationships of mite communities between above- and below-ground habitats and the effects of abiotic factors on mite communities. We collected 49 families, 86 genera, and 1284 mites. In the external cave environment, we captured 1052 mites from 72 genera and 45 families; in the internal cave environment, we captured 232 mites from 46 genera and 29 families. The abundance, richness of genera, and diversity parameters of the mite community decreased from the cave entrance to the cave interior with decreasing light intensity. Oribatid mites dominated the mite community. Protoribates and Scheloribates were the dominant genera, along with Tectocepheus and 11 other genera, which primarily distinguished the mite communities among different habitats. Forty endemic taxa were found in the external cave environment, compared to 14 endemic taxa in the internal cave environment. The mite community showed a strong preference for the cave ecosystem habitat. Temperature, humidity, and soil nitrogen content significantly influenced the distribution pattern of mite communities (VIP > 0.8, p < 0.05).

CO&lt;sub&gt;2&lt;/sub&gt; hypogene speleogenesis in an endogenic travertine system, Mesa del Oro, New Mexico, USA

The Mesa del Oro travertine, deposited by upwelling CO2-rich spring waters, is a large and thick mantle of calcite overlying soft Triassic Chinle Formation mudstones in western central New Mexico, USA. The travertine contains a system of small caves known as the Pronoun Cave Complex. Whut Cave is the largest known cave in the complex. While the travertine hydrologic system is no longer active, there is ample evidence that Whut Cave was formed by hypogene speleogenesis. The Whut Cave entrance is a small roughly circular shaft that descends ~four meters and intersects a linear fissure-controlled passage. Mn-oxide was once mined below the entrance, leaving a five-meter-deep pit that represents the path of upwelling waters that were likely charged with CO2 and supersaturated with CaCO3 once reaching the surface. The roomiest part of the cave is immediately adjacent to the entrance, defining where most of the upwelling of groundwater and gases took place. Gypsum and other sulfates were only noted microscopically. A sample of travertine at the surface near the entrance yielded a uranium-series age beyond the limit of the method and a δ234U age of 735 ± 109 ka BP (before present). A piece of breccia vein in the mine dump associated with the Mn-oxide ore, and a rill of a drape-like crust on the cave wall, both interpreted to be products of hypogene speleogenesis and representing the oldest speleogenetic material, yielded δ234U ages of 848 ± 110 and 723 ± 109 ka BP. Altogether, materials interpreted to be speleogenetic yielded ages of ~900 – 300 ka BP. Although the cave is dry and hydrologically inactive today, cave development by CO2 hypogene speleogenesis was coeval with endogenic travertine deposition and nearby volcanism. Our interpretation suggests that all these events are linked.

From the front door to the basement: Invertebrate communities' structure as a proxy for determining cave zonation in Neotropics

AbstractIn caves, the absence of natural light in deeper regions starkly contrasts with the entrance areas, which still exhibit a light gradient extending into the cave interior. This interplay with the structural gradient of the environment potentially exerts distinct influences on invertebrate communities residing in different cave light zones. To investigate this, we formulated a hypothesis positing that communities within distinct cave light zones respond differently to habitat structure and microclimatic conditions. Our approach involved a spatial multi‐scale sampling of invertebrates and the application of statistical analyses to contrast the responses of communities inhabiting photic and aphotic zones. Photic zone richness is influenced by factors such as air moisture, resource availability, root presence, and shelter diversity. In contrast, the richness of communities in aphotic zones is shaped by resource availability, the presence of roots, branches, and distance from the cave entrance. As expected, the richness in the photic zone surpasses that of the deeper regions, highlighting the challenges faced by invertebrates attempting to establish themselves in the aphotic zone. The species composition of faunal communities varied predictably from the entrance to the aphotic zone, and the three most important factors driving this variation were geographic distance, humidity, and distance from the entrance. The composition between these cave zones differs significantly, primarily due to the high number of obligate cave species predominantly inhabiting the aphotic region. Indeed, communities associated with different cave zones exhibit distinct responses to resource, microclimatic, and structural variables.Abstract in Portuguese is available with online material.

First insights into the age of the giant ice deposits in the Eisriesenwelt cave (Austria)

Frozen water is the most widespread type of ice present in ice caves and forms ice stalagmites and stalactites as well as floor ice, which is often several meters thick. Organic macroremains are commonly rare in this type of cave ice, which makes it difficult to establish a chronology and severely limits the use of such ice deposits as paleoenvironmental archives. Here, the chronology of such ice deposits in the inner part of the glaciated Eisriesenwelt, one of the world’s largest ice caves located in the European Alps of Austria, is determined by a combination of radiocarbon and 230Th dating of cryogenic calcite. The data suggest that this cave ice has formed over the last three millennia, with a marked increase in the average accumulation rate during the thirteenth century, coinciding with the onset of the Little Ice Age in the Alps. Data from a second site closer to the entrance suggests that large parts of this tourist cave were likely ice-free during the Medieval Warm Period and that a substantial part of the ice is probably a relic of the Little Ice Age. The current warming has already penetrated deeper into the cave than during the Medieval Warm Period, although air exchange during the warm season is restricted by a door at the cave entrance.

Checklist of land snail species of Gua Rumbang, Sarawak, Malaysian Borneo (Mollusca, Gastropoda), with a description of a new species, Diplommatinarumbangensis sp. nov.

The current study presents an annotated checklist of the land snail species in the vicinity of the limestone hill of Gua (= cave) Rumbang, an outcrop located at the district of Padawan, Sarawak, Malaysian Borneo. The sampling was conducted at the surrounding areas and near the cave's entrance. A total of 62 species, involving 19 families and 38 genera, were recorded. Comparison with previous surveys made in the Bau limestone hills revealed similarities with respect to the species-rich families Diplommatinidae and Cyclophoridae, and the genera Kaliella and Diplommatina, highlighting the regional consistency of the land snail diversity of the Bau-Padawan-Serian cluster. Possibly because of its smaller size, Gua Rumbang is home to two endemic species, while there are eight endemic species in the Bau limestone karsts. This suggests a potential for a significant species diversity within the areas of the limestone ranges that remain to be explored. Nonetheless, the occurrence of endemic species in Gua Rumbang highlights the need to conserve certain areas within the Padawan limestone range since hitherto no protected areas have been proposed in this region. In this checklist, a new species for science is also described, namely, Diplommatinarumbangensissp. nov.

Transmission characteristics and the factors influencing stable oxygen isotopes in precipitation, soil water, and drip water in Remi Cave, Western Hunan, China

Understanding the modern transport processes of δ18O between different waters in cave systems can provide a basis for the paleoenvironmental interpretation of records of stalagmite δ18O. We conducted monthly in-situ monitoring of local precipitation, soil water at three different soil depths, five drip water sites and environmental parameters in Remi cave, Western Hunan Province, Central China, from December 2020 to January 2024. During the monitoring period, due to differences in geological structure and ventilation effect at different locations within the cave, cave air temperature and relative humidity gradually remained constant from the cave entrance to the deep parts of the cave. On intra-annual timescales, precipitation δ18Op were depleted in the wet season and enriched in the dry season, which were mainly controlled by changes in moisture sources, upstream convective activity, and rainout effects. With the increasing thickness of the soil layer above the cave, soil water δ18Osoil gradually became negative and leveled off, possibly because shallow soil water responded sensitively to local year-round precipitation, accompanied by surface evaporation. While, deep soil water with more negative δ18O, may be mainly replenished by heavy precipitation during the wet season, but the effect of water retained in the soil from preceding years couldn’t be excluded and would be needed to verify by conducting more monitoring studies on the variation of δ18Osoil covering the long period. The mean δ18O values of drip water at sites D1 and D2 near the cave entrance were heavier than that of shallow soil water and precipitation, possibly due to evaporation from the thin overlying soil layer, together with ventilation effect. There were seasonal variations of δ18Od values at site D5 in the deep parts of the cave, which may be associated with the seasonal variation of drip rate at this site. Due to the smoothing effect of soil layer and epikarst zone, there were no seasonality in δ18Od values at sites D3 and D4, in the middle and deep parts of the cave. The mean δ18Od at these two sites were lighter than amount-weighted annual mean δ18Op, and close to the deep δ18Osoil and the wet-season amount-weighted mean δ18Op values. This suggests that the thick soil layer overlying the cave raises the precipitation threshold, causing these sites to be mainly recharged by heavy rainfall in the wet season. Therefore, the δ18O of stalagmites growing under these drip sites may mainly inherit the wet-season δ18Op signal. The short monitoring period of this study (three years) and the lack of modern calcite δ18O data, mean that caution is need in interpreting stalagmite δ18O on a timescale longer than that of this study.

First Survey of the Sponge Community of a Semi-Submerged Marine Cave along the Adriatic Apulian Coast

Mediterranean marine caves have been categorized as both biodiversity reservoirs and vulnerable habitats. However, only a few studies have focused on Porifera assemblages within marine caves along the Adriatic Apulian coast (southern Italy). In this study, the sponge fauna of the Rondinella cave, a semi-submerged marine cave along the coast of Bari (Southern Adriatic Sea), was investigated for the first time. The use of advanced image analysis in combination with targeted sampling has made it possible to determine the spatial distribution and diversity of Porifera along a transect from the entrance to the end of the cave. Data analysis clustered the stations into two groups, separated according to the distance from the entrance and corresponding to the cave entrance and the semi-dark zone. Sponges were found at all stations covering a considerable part of the substrate, with the highest cover values occurring in the semi-dark zone. A total of 54 sponge taxa were identified: 49 Demospongiae, 3 Homoscleromorpha, and 2 Calcarea. Six species are new records for the Apulian marine caves, one species represents a new record for marine caves, and two species are new findings for the southern Adriatic Sea.

Methane sink of subterranean space in an integrated atmosphere-soil-cave system

CH4 serves as an important greenhouse gas, yet limited knowledge is available in global and regional CH4 cycling, particularly in widely distributed karst terrain. In this study, we investigated an upland in Puding Karst Ecosystem Research Station, and explored CH4 concentration and/or flux in atmosphere, soil and cave using a closed static chamber method and an eddy covariance system. Meanwhile, we monitored atmospheric temperature, precipitation, temperature and wind velocity in the cave entrance. The results demonstrated that atmospheric CH4 and actual soil CH4 fluxes in the source area of eddy covariance system were −0.19 ± 8.64 nmols−1m−2 and -0.16 nmols−1m−2 respectively. The CH4 concentrations in Shawan Cave exhibited 10 ∼ 100-fold lower than that of the external atmosphere. CH4 oxidation rate dominated by methane-oxidizing bacteria was 1.98 nmols−1m−2 in Shawan Cave when it combined with temperature difference between cave and external atmosphere. Therefore, CH4 sink in global karst subterranean spaces was estimated at 106.2 Tg CH4 yr−1. We supplemented an understanding of CH4 cycling paths and fluxes in karst terrain, as well as CH4 sinks in karst subterranean space. Further works require to establish a karst ecosystem observation network to conduct long-term integrated studies on CH4 fluxes regarding atmosphere, soils, plants and caves.

Functional convergence underground? The scale‐dependency of community assembly processes in European cave spiders

AbstractAimQuantifying the relative contribution of environmental filtering versus limiting similarity in shaping communities is challenging because these processes often act simultaneously and their effect is scale‐dependent. Focusing on caves, island‐like natural laboratories with limited environmental variability and species diversity, we tested: (i) the relative contribution of environmental filtering and limiting similarity in determining community assembly in caves; (ii) how the relative contribution of these driving forces changes along environmental gradients.LocationEurope.Time periodPresent.Major taxa studiedSubterranean spiders.MethodsWe used data on distribution and traits for European cave spiders (n = 475 communities). We estimated the trait space of each community using probabilistic hypervolumes, and obtained estimations of functional richness independent of the species richness of each community via null modelling. We model functional diversity change along environmental gradients using generalized dissimilarity modelling.ResultsSixty‐three percent of subterranean spider communities exhibited a prevalence of trait underdispersion. However, most communities displayed trait dispersion that did not depart significantly from random, suggesting that environmental filtering and limiting similarity were both exerting equally weak or strong, yet opposing influences. Overdispersed communities were primarily concentrated in southern latitudes, particularly in the Dinaric karst, where there is greater subterranean habitat availability. Pairwise comparisons of functional richness across caves revealed these effects to be strongly scale‐dependent, largely varying across gradients of cave development, elevation, precipitation, entrance size and annual temperature range. Conversely, geographical distance weakly affected trait composition, suggesting convergence in traits among communities that are far apart.Main conclusionsEven systems with stringent environmental conditions maintain the potential for trait differentiation, especially in areas of greater habitat availability. Yet, the relative influence of environmental filtering and limiting similarity change with scale, along clear environmental gradients. The interplay of these processes may explain the assembly of species‐poor subterranean communities displaying high functional specialization.

Cyanobacteria and Algae in the Karlamanskaya Cave (Bashkortostan Republic, Russia)

The article presents data on the composition and structure of cyanobacterial-algal cenoses of various habitats of the Karlamanskaya Cave. The study identified 46 species and intraspecific taxa of cyanobacteria and algae belonging to 5 divisions (Cyanobacteria – 17 species and intraspecific taxa, Bacillariophyta – 12 species and intraspecific taxa, Chlorophyta – 14 species, Charophyta – 1 species, Ochrophyta – 2 species), 7 classes, 16 order, 28 families and 36 genera. Leptolyngbya boryana (Gom.) Anagn. et Kom., Oscillatoria rupicola (Hansgirg) Hansgirg ex Forti, Luticola mutica (Kütz.) Mann, Mychonastes homosphaera (Skuja) Kalina et Punс., Chlorella vulgaris Beijerink present the dominant complex of cyanobacteria and algae in all studied habitats. Cyanobacteria dominate in all biotopes of the cave except aquatic ones where diatoms predominated. The maximum number of species was found in the soil at the cave entrance and in the soil of the illuminated cave zone: 31 and 29 species respectively. The lowest number was found in the soil and on the walls (16 and 11 species respectively). Ecological analysis of cyanobacterium and algae revealed 12 life forms: Сh9B9P5X5CF5hydr4amph2PF1NF1C1M1H1. Most of the life forms were found in the illuminated cave zone: in the soil (10 forms), on the wall (10 forms) and at the cave entrance (11 forms). The ecobiomorphs composition of the dark zone is the poorest (5 forms).

Microclimatic Influences on the Abundance of Three Non-Troglobiont Species

Subterranean environments are often characterized by a natural gradient of microclimatic conditions and trophic resources, showing a higher trophic availability and a lower microclimatic stability in the shallowest area (close to the cave entrance), while the opposite occurs in the deepest sections. The shallowest areas of subterranean environments (e.g., the entrance and twilight zone, Mesovoid Shallow Substratum) act as ecotones between the surface habitats and the deep areas, creating a particular habitat which can be exploited by numerous species with different degrees of adaptation to subterranean environments. Species living in these ecotones may hold a key role in sustaining the entire ecosystem, as they are likely one of the major drivers of allochthonous organic matter. Indeed, these species are usually facultative cave-dwellers, meaning that they are able to exit and forage on the surface. Once these species are back inside the cave, they provide the local community with different typologies of organic matter (e.g., feces, eggs), which represent one of the most important sources of organic carbon. Therefore, studying which ecological features may exert significant effects on the abundance of these species may be of great help in understanding the ecosystem dynamics and the functional role of each species. In this study we analyzed the data collected through a year-round monitoring program, aiming to assess the potential effects that both abiotic and biotic features may have on the abundance of three facultative cave species. We focused on seven caves located in Monte Albo (Sardinia, Italy). The cave environments were divided into 3-meter sectors, and within each cave sector, microclimatic and biological data were seasonally recorded. We focused on the following facultative cave species: the spiders Metellina merianae and Tegenaria sp. and the snail Oxychilus oppressus. Different relationships were observed between the ecological features and the abundance of the three species. The two spiders were more abundant in warmer cave sectors closer to the cave entrance, especially the M. merianae. On the other hand, the snail tended to be more abundant farther from the cave entrance and in more illuminated cave sectors, probably because sunlight promotes the abundance of some of its trophic resources (e.g., lichens, vegetation). Furthermore, O. oppressus was the only species whose abundance and cave distribution was significantly affected by seasonality. This study provides useful and novel information to understand the population dynamics of facultative cave species and their role in subterranean ecosystems.

Chronology of Upper Paleolithic human activities recorded in a stalagmite at Points Cave (Aiguèze, Gard, France)

AbstractIn this article, we propose an approach to reconstruct the timing of human activity at Points Cave, an Upper Paleolithic rock art site located in the middle of the Ardèche River Gorge (Rhône valley, France), based on the dating and characterisation of a stalagmite containing soot. Points Cave (‘Grotte aux Points’ in French), also called the ‘little sister of Chauvet Cave’, is famous for its parietal art including a series of dots made of palm prints. A large number of stalagmites formed in the cave during the last 500 ka. However, quarrying of the cave floors during historic times led to the partial destruction of the sedimentary deposits, and many of the stalagmites were found lying on the floor. In particular, one of them (STM‐18‐04) showed the presence of at least four dark layers in cross‐section, which appeared as possible remnants of fire‐related activities in the cave. Despite being present at the same site, no other specific link between STM‐18‐04 and the rock art has been documented. This stalagmite, however, allows us to identify phases of human presence, located at the cave entrance. To do so, we performed a series of analyses to determine its period of growth and the nature of the dark layers that it contains. Scanning electron microscopy and Raman microspectroscopy confirmed that the dark layers include soot, and uranium‐series dating indicated that the fire events occurred, respectively, around 14,200–14,100 and 12,500 years ago, in agreement with the radiocarbon ages of charcoal specimens recovered from the excavation areas nearby. We thus highlighted phases of human activity at the site during the Upper Magdalenian and/or beginning of the Epipaleolithic. By comparing our results with the regional paleoclimatic record, the soot layers trapped in the stalagmite appear to be synchronous with two cold periods, likely the Older Dryas and the Younger Dryas.