Small mammal community ecology

Summary The abundance of food in natural 1-ha plot of shortgrass prairie was artificially manipulated by adding alfalfa pellets and whole oats on a regular schedule. The small mammal species naturally inhabiting the manipulated food plot did not respond in either their density or weight to the supplemented food. However, a new specialized seed-eating species, Dipodomys ordii, invaded the food plot and persisted in relatively high density. As a result of this colonization, species diversity was significantly higher on the food plot relative to the unmanipulated control plot. In a second experiment, application of water and nitrogen to two 1-ha plots of shortgrass prairie resulted in increased productivity. However, the increased production on this latter treatment was associated with vegetation growth and thus major changes in habitat structural characteristics relative to the control treatment. Two new species, Microtus ochrogaster and Reithrodontomys megalotis, colonized the nitrogen+water treatment, but other small mammal species resident to the shortgrass prairie largely avoided this treatment. As a result of this manipulation, species diversity was significantly lower than the species diversity on the control treatment. These two results agree with the MacArthur prediction regarding how species diversity responds to an increase in production of scarce resources without changes in other habitat variables, and to an increase in productivity associated with changes in other habitat variables.     

Filter mesh size and food particle uptake by Daphnia

Food size selection of four Daphnia, species (D. magna, D. hyalina, D. galeata, D. pulicaria) was investigated using spherical plastic beads as artificial food and with small bacteria. The size of the particles ranged from 0.1 to 35 m with special emphasis to the particle diameters between 0.1 and 1 m. In one set of experiments a mixture of differently sized particles was offered as food suspension and the selectivity of filtering was determined by comparing the size spectrum of the particles found in the gut contents with the spectrum in the food suspension. In a second series of experiments suspensions of uniformly sized particles were offered to single animals and their feeding activity was observed directly. In both types of experiments the mesh sizes of the filtering apparatus of the respective animals studied were measured after the experiments by, scanning electron microscopy. The mean sizes of the filter meshes were about 0.4–0.7 m. In all experiments the size of the particles found in the gut or those which caused high feeding activities were larger than the smallest mesh sizes of the filters. As a consequence simple mechanical sieving provides a sufficient explanation for the mechanism of particle retention of the filtering process in Daphnia. D. magna was found to feed with high efficiency on suspended freshwater bacteria, the residual species investigated showed low filtering efficiencies when bacteria were offered as food.The present study was supported by Deutscher Akademischer Austauschdients     

Influence of food size and food quantity on the feeding of the mussel Dreissena polymorpha

Summary In common with many other suspension feeders, the freshwater mussel Dreissena polymorpha has a maximum filtration rate at low food concentrations and a maximum ingestion rate at high food concentrations. These high rates, which reflect the potential maximum food uptake of the animal, are called the filtration capacity and the ingestion capacity respectively. The ingestion capacity was attained without forming pseudofaeces with Chlamydomonas reinhardii as food. The incipient limiting level could be calculated as the quotient of these two values. A decrease of the filtration rate at high food concentrations was correlated with changes in pumping activity, which showed more frequent interruptions, or a lower level of water transport. Dreissena can filter out particles of diameter greater than 0.7 m from the water. Retention reaches a plateau at about 5 m particle diameter. Scanning electron micrographs of the arrangement of the cilia on the gill filaments are given.     

Time scales of change in the San Francisco Bay benthos

Results from multi-year investigations in the San Francisco Bay estuary show that large abundance fluctuations within benthic macroinvertebrate populations reflect both (1) within-year periodicity of reproduction, recruitment, and mortality that is not necessarily coincident with seasonal changes of the environment (e.g., the annual temperature cycle), and (2) aperiodic density changes (often larger than within-year fluctuations) following random perturbations of the environment.Density peaks of the small, short-lived estuarine invertebrates that comprise the vast majority of individuals in the bay's relatively homogeneous benthic community normally occur between spring and autumn depending on the species, in large part a reflection of reproductive periodicity. However, because mild winters permit reproductive activity in some of the common species throughout much of the year, other factors are important to within-year density fluctuations in the community. Seasonally predictable changes in freshwater inflow, wind and tidal mixing, microalgal biomass, and sediment erosion/deposition patterns all contribute to observed seasonal changes in abundance. For example, the commonly observed decline in abundance during winter reflects both short-lived species that die after reproducing and the stress of winter conditions (e.g., inundation by less saline, sediment-laden water and the decline in both planktonic and benthic algal biomass — a direct source of food for the shallow-water benthos). On the other hand, data from several studies suggest that observed recruitment and mortality may in fact be the migration of juveniles and adults to and from study sites. For example, the common amphipod Ampelisca abdita apparently moves from shallow to deep water, or from up-estuary to down-estuary locations, coincident with periods of high river runoff in winter. Growth of individuals within the few studied species populations is also highly seasonal, and appears to be coincident with seasonal increases in the abundance of planktonic and/or benthic microalgae.Two multi-year studies have shown that, in addition to within-year periodicity, major restructuring of the benthic community can occur as a result of anomalous (usually climate-related) perturbations of the benthic habitat. For example, during wet years freshwater-intolerant species disappear from the upper part of the estuary and from shallow areas of the bay. During a two-year drought these same species colonized the extreme upper end of the estuary in large numbers. Other aperiodic perturbations include localized instances of sediment erosion or deposition and algal mat accumulations that greatly depress abundance. Additionally, there is evidence (observations that the clam Macoma balthica establishes large populations only when the amphipod A. abdita is not abundant) that species interactions can contribute greatly to interannual variations. Thus, while community composition may change little over the long term, year-to-year predictability of species abundances is low.     

Competitive exclusion between insular Lacerta species (Sauria,Lacertidae)

Summary Competetive exclusion between Lacerta sicula and L. melisellensis characterizes the small islands of the Adriatic Sea.In 1958 and 1959 M. Radovanovié introduced Lacerta sicula or Lacerta melisellensis onto islands exclusively occupied by the other species. During the summer of 1971 follow-up observations were made on three of these islands, two of which completely lacked representatives of the introduced species. On the third island, the introduced species appears to be replacing the native form. Minor habitat differences permit coexistence, however the situation is dynamic and probably not at equilibrium. A reciprocal introduction involving the two species on the islands of Pod Kopite and Pod Mraru is announced.     

Relations between hydrological variables and year-class strength of sportfish in eight Florida waterbodies

Hydrological variables have influenced fish recruitment in lakes, reservoirs and rivers. We evaluated how annual and seasonal hydrological variables were related to year-class strength (i.e., residuals from catch curves) of sportfish across eight Florida waterbodies (four rivers and four lakes). Multiple regression equations computed for black bass Micropterus spp. were combined across rivers and year-class strength was negatively related to spring median flow rates and in some cases positively related to winter median flow rates (all p0.10). Conversely, Lepomis spp. residuals combined from the rivers indicated that year-class strength was positively related to median flow rates in the fall prior to spawning and negatively related to post-spawn fall median flow rates (all p0.10). Fish recruitment combined across lakes were not related to water levels in this study, although within lake relationships did occur in some instances. Ecological implications of this work include regulations such as minimum flows and levels (MFLs) regarding sportfish species. Impacts of hydrology on year-class strength of sportfish were stronger in rivers than in lakes for these Florida systems. High flows at least once every 3years in the fall may allow inundation of floodplain habitat, providing favorable environmental conditions for Lepomis spp. reproduction. Setting MFLs during periods of drought (i.e., 3years or more) should consider impacts to short-lived species such as Lepomis spp.     

Interspecific Differences of Leaf Gas Exchange and Water Relations of Three Evergreen Mediterranean Shrub Species

Leaf gas exchange and plant water relations of three co-occurring evergreen Mediterranean shrubs species, Quercus ilex L. and Phillyrea latifolia L. (typical evergreen sclerophyllous shrubs) and Cistus incanus L. (a drought semi-deciduous shrub), were investigated in order to evaluate possible differences in their adaptive strategies, in particular with respect to drought stress. C. incanus showed the highest annual rate of net photosynthetic rate (P _N) and stomatal conductance (g _s) decreasing by 67 and 69 %, respectively, in summer. P. latifolia and Q. ilex showed lower annual maximum P _N and g _s, although P _N was less lowered in summer (40 and 37 %, respectively). P. latifolia reached the lowest midday leaf water potential (₁) during the drought period (–3.54±0.36 MPa), 11 % lower than in C. incanus and 19 % lower than in Q. ilex. Leaf relative water content (RWC) showed the same trend as ₁. C. incanus showed the lowest RWC values during the drought period (60 %) while they were never below 76 % in P. latifolia and Q. ilex; moreover C. incanus showed the lowest recovery of ₁ at sunset. Hence the studied species are well adapted to the prevailing environment in Mediterranean climate areas, but they show different adaptive strategies that may be useful for their co-occurrence in the same habitat. However, Q. ilex and P. latifolia by their water use strategy seem to be less sensitive to drought stress than C. incanus.     

An Individual Based Model of the Impact of Suboptimal Habitat on Survival of the Grey Bush Cricket, Platycleis Albopunctata (Orthoptera: Tettigoniidae)

We developed an individual based model that investigates the importance of suboptimal habitats for the survival of the grey bush cricket Platycleis albopunctata living in a core habitat. Our model consists of two submodels. The first describes the demographic growth of the cricket known to mainly depend on temperature. The second introduces a simple heterogeneous habitat that consists of two areas of variable size and different suitability for reproduction. An optimal habitat is surrounded by a suboptimal habitat and both together are located within an unsuitable area. Applying Monte Carlo simulations we demonstrate that the extinction probability of a bush cricket population is significantly lower in an optimal habitat with a surrounding suboptimal habitat than without. Even small suboptimal habitats are sufficient to significantly reduce the extinction risk of the core population. For a bush cricket population living in a heterogeneous habitat mean minimum viable population estimates range from 13000 to 15000 adults, whereas 30000 adults are required for a population living in an optimal habitat without a surrounding suboptimal habitat. Thus, the presence of a suboptimal habitat can reduce minimum viable population by 50%. For any species, our model predicts that the type of dispersal between optimal and suboptimal habitat and the type of habitat selection determine whether suboptimal habitat is useful or detrimental for species persistence.     

A life history model for the San Francisco Estuary population of the Chinese mitten crab, <Emphasis Type="Italic">Eriocheir sinensis</Emphasis> (Decapoda: Grapsoidea)

First discovered in San Francisco Bay in 1992, the Chinese mitten crab,Eriocheir sinensis, has become established over hundreds of km² of the San Francisco Estuary. Ecological and economic impacts of this invasive species motivated our search for a greater understanding of the crabs life history as an important step in better management and control. Data for this life history model comes from the authors research and scientific literature. Juvenile crabs migrate from the Estuary into fresh water where they develop into adults. Environmental signals may stimulate gonad development that is followed by a downstream migration beginning at the end of summer. Mating occurs after the crabs reach saline water. Embryos are carried until hatching, and the larvae undergo five zoeal stages before settlement. Our model projects rates of development at various temperatures and growth increments, supports a minimum of 2 years in low salinity or freshwater habitat, and predicts that most California mitten crabs are at least 3 years old before becoming sexually mature. Environmental factors strongly influence the timing and duration of the crabs life stages, and are discussed in the context of a gradient of development times for worldwide populations of this important invasive species.     

The energy budget of two sympatric Daphnia species in Lake Constance: productivity and energy residence times

Summary Two Daphnia species, D. hyalina and D. galeata, are living in Lake Constance. Both populations show logistic growth, with the phase of exponential increase in May and the phase of steady state during the summer. In spring, food is not limited and both daphnids reveal an exploitative strategy: females mature early, primiparae are small, egg weights are small, but clutch sizes are large. From June on, when food limiting conditions prevail, D. hyalina starts to migrate vertically with a diurnal rhythm whereas D. galeata keeps on living in the epilimnion over the whole season. The differing thermal environments of the populations lead to short generation times (age of first reproduction) of 11 days for D. galeata in mid-summer, and to 47 days (July) for D. hyalina. The annual production (P) of D. hyalina and D. galeata were 18 and 24 g DW/m², respectively. The average standing stocks (B) were 1.6 and 0.9 g DW/m². This corresponds to turnover rates of 11 x and 27 x per season (200 days), and to turnover times of 18 days and 7.5 days, respectively. From 1980 to 1982 the cumulative annual primary production (PPR) varied between 260 and 330 g C/m². The common productivity (P) of the functional component Daphnia (=sum of both Daphnia species) followed the PPR, but the Daphnia stading stock was constant at 2.5 g DW/m². The increase of secondary production (P) was a consequence of a shift in abundance between the two Daphnia species: at low PPR, D. hyalina was 4 x more abundant, but at high PPR, the two species were equally abundant. Such internal regulatory mechanism within a system component is in accordance with the hypothesis of Cheslak and Lamarra (1981): increase of energy residence time (B/R) with declining nutrients and increasing strength of competitive interrelationships within a given functional component of an ecosystem.This research was supported by the Deutsche Forschungsgemeinschaft within Sonderforschungsbereich Stoffhaushalt des Bodensees (SFB 248)     

Influence of temperature,oxygen and food availability on the migrational activity of bathyal benthic foraminifera: evidence by microcosm experiments

Foraminifera are a dominant group of amoeboid protists in the deep-sea and play possibly a significant role in decomposition processes of incoming organic matter. In order to study the poorly known ecology of these protozoans, microcosm experiments with living bathyal benthic foraminifera have been conducted. Foraminifera from 2880 m and shallower water depths were successfully maintained and their movement patterns investigated. By video documentation, high mean migration speed of 20,02 (N = 22) and 24,48 m min^-1 (N = 10) at 4 °C were found for species such as Hoeglundina elegans and Quinqueloculina seminula from 1847 m and 1921 m water depth, respectively. The results demonstrate that some bathyal foraminifera have migration speeds comparable to those of shallow water species. Environmental factors such as temperature, food concentration and oxygen content showed a marked influence on the migration of some species. An increase in temperature from 10 °C to 15 °C resulted in an increase of 35% in the migration speed of Allogromia spp. However, other species reacted differently. Higher food concentration resulted in a decrease in speed of some species. While in Quinqueloculina lamarckiana speed was not greatly affected by a low oxygen content in the sediment, other foraminifera responded to oxygen depletion by migration to the surface layers. Observations of benthic foraminifera in the laboratory microcosms are discussed in relation to microhabitats and the fate of organic matter on the sea floor and in the sediment.     

The effects of Chilomonas on the life history traits of [-2pt] Daphnia longispina under semi-natural conditions and the implications for competition in the plankton

Assuming that heterotrophic flagellates (H.F.) can sustain cladoceran life cycles, particularly at periods of low food and high detritus conditions, the growth, reproduction and life span of Daphnia longispinawere studied under conditions of summer food limitation. They were fed both natural resources and natural food enriched with a culture of the colourless Chilomonas (ovoid cell, 8 × 25 m). Four H.F. morphotypes occurred in the natural water and the first experiments with Daphnia, showed that the cladoceran would most easily ingest those of 5 m–10 m, while the addition of Chilomonas severely depressed the H.F. of 2 m. The capability of this flagellate to ingest small H.F. was confirmed using fluorescent particles ranging from 0.94 to 3.95 m. As a consequence, Daphnia could control the abundance of H.F., but also compete with the largest morphotypes. To study the influence of the H.F. on the life span of Daphnia, the cladoceran was acclimated for two generations, before the start of the experiments. In semi-natural conditions, constant temperature, without predators and fed natural water, the summer daphnids achieved smaller sizes, produced fewer offspring and lived for a shorter time than when Chilomonas was added to their diet. Despite the addition of 560 g C l^-1, this was not sufficient to enhance the Daphnia reproduction to the level of the spring population fed natural water. These results clearly illustrate that the heterotrophic flagellates contributed significantly to improving the reproduction and survival of the daphnids. They emphasise the importance of the microbial loop as a link to larger consumers, particularly when unpalatable or nutritionally inadequate algae are dominant, which is often so in lakes during summer.     

Nest site selection and nesting success of five species of passerines in a South American open Prosopis woodland

I analyzed nest site preferences and whether these preferences were linked to nest success of five bird species breeding in an arid area of southern South America. Most nests (90%) were located in three plant species (Geoffroea decorticans, Capparis atamisquea, and Atriplex lampa). Serpophaga griseiceps, Poospiza ornata, and P. torquata nested in plants with size significantly different from randomly selected plants. At the mesohabitat scale (i.e., habitat patch surrounding the nest), four species showed clear differences from random patches within the general habitat, and the remaining species (Saltatricula multicolor) showed a non-significant trend. The daily survival rate of S. griseiceps nests placed in the preferred plant species (i.e., G. decorticans) was lower than those in the other nest-plants. In the other four bird species, nest survival did not differ between preferred and other plants used for nesting. At the scale of microhabitat (i.e., plant size and location of the nest inside the plant), no significant differences were detected between unsuccessful and successful nests. Similarly, unsuccessful nest patches did not differ significantly in habitat features from those that were successful. High nest predation rates found in this habitat (around 85% for the total assemblage) and a relatively high diversity of predators (and of predation tactics) appear to impede the presence of safe sites for nesting (i.e., there are trade-offs between avoidance strategies).     

Seasonal and environmental influences on antioxidative protection inPeridinium gatunense in Lake Kinneret

As the only freshwater lake in Israel, Lake Kinneret serves a number of important functions which directly rely upon the viability of the water. The annual outbreak of a dinoflagellate bloom strictly governs the nature of the macro and micro food web and ultimately determines water quality.The freshwater dinoflagellatePeridinium gatunense is subject to a wide range of environmental stresses throughout the spring bloom period. It was confirmed that SOD played an important antioxidative maintainance role throughout the bloom, especially during periods of relatively high photosynthetic activity (820 mg C m^–2 day^–1), when activity reached 500 Units SOD mg protein^–1. In addition, high light stress (>300 mol photons m^–2 s^–1) induced SOD activity, despite the low dissolved inorganic carbon (DIC) concentrations at the end of the bloom (1.3 mM). Catalase activity was only significant at the end of the bloom, peaking at 120 mol O₂ mg protein^–1 min^–1, when induced by photorespiratory activity.A series of experiments withPeridinium cultures showed that 2 × 10^–4 M ascorbate inhibited catalase activity >50% within 15 min incubation, bothin vivo andin vitro. It is suggested that the high concentrations of ascorbate, found previously inPeridinium during early and mid-bloom (0.2–1.6 mM), not only eliminate H₂O₂ build-up, but also prevent (directly or indirectly) the induction of catalase.     

Distribution and toxicity of a new colonial Microcystis aeruginosa bloom in the San Francisco Bay Estuary,California

The first distribution, biomass and toxicity study of a newly established bloom of the colonial cyanobacteria Microcystis aeruginosa was conducted on October 15, 2003 in the upper San Francisco Bay Estuary. Microcystis aeruginosa was widely distributed throughout 180 km of waterways in the upper San Francisco Bay Estuary from freshwater to brackish water environments and contained hepatotoxic microcystins at all stations. Other cyanobacteria toxins were absent or only present in trace amounts. The composition of the microcystins among stations was similar and dominated by demethyl microcystin-LR followed by microcystin-LR. In situ toxicity computed for the >75 m cell diameter size fraction was well below the 1 g l^–1 advisory level set by the World Health Organization for water quality, but the toxicity of the full population is unknown. The toxicity may have been greater earlier in the year when biomass was visibly higher. Toxicity was highest at low water temperature, water transparency and salinity. Microcystins from the bloom entered the food web and were present in both total zooplankton and clam tissue. Initial laboratory feeding tests suggested the cyanobacteria was not consumed by the adult copepod Eurytemora affinis, an important fishery food source in the estuary.     

The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Light in the photosynthetically active region

The vertical zonation of the Antarctic cryptoendolithic community appears to form in response to the light regime in the habitat. However, because of the structure of the habitat, the light regime is difficult to study directly. Therefore, a mathematical model of the light regime was constructed, which was used to estimate the total photon flux in different zones of the community. Maximum fluxes range from about 150m photons m^–2 s^–1 at the upper boundary of the community to about 0.1m photons m^–2 s^–1. Estimates of the annual productivity in the community indicate that the lowest zone of the community is light limited, with the maximal annual carbon uptake equivalent to less than the carbon content of one algal (Hemichloris) cell.     

A comparison of the fatty acid composition of Gammarus lacustris and its food sources from a freshwater reservoir, Bugach, and the saline Lake Shira in Siberia, Russia

We studied fatty acid (FA) composition in samples from bodies and intestinal contents of the littoral amphipod Gammarus lacustris Sars, from the Bugach freshwater reservoir. Simultaneously, samples of seston and bottom sediments were also collected from the reservoir during early August. There were no differences in FA composition of gut contents, seston and sediments of pebbly bottom. Seston was the main food source of Gammarus but some FAs Gammarus got from sediments. The FA composition of G. lacustris and seston from the Bugach freshwater reservoir were compared with those of the animals from the saltwater Lake Shira (Siberia). While FA composition of the two Gammarus populations differed significantly, those of seston were practically similar: the composition of long-chain unsaturated fatty acids, 20:53, 22:63 and 20:46, were significantly higher in animals from saline Shira Lake, whereas 16:1 and 16:0 were higher in the freshwater populations of amphipods from the Bugach freshwater reservoir. Taking into account the relevant literature data, we hypothesise that this difference in C16 acid might be a distinguishing characteristic of FA composition of freshwater and saltwater crustaceans.     

Dynamics of sahelian pastures in relation to drought and grazing

Summary The dynamics of the vegetation were studied in the transition zone from the savannah to the Sahel in order to distinguish between the influence of the recent drought and the influence of overgrazing on the natural rangelands. The drought affected especially the different plant species at the northern limit of their habitat. It is, however, not well possible to speak of a sahelisation of the savannah, since the species in regression were replaced by invaders, like Borreria spp, and not by true Sahelian species. An exception was Blepharis linariifolia, which moved to the south. Grazing affected good fodder grasses like Andropogon gayanus, which were replaced by a legume with a short growth cycle, Zornia glochidiata, and an unpalatable annual grass Elionurus elegans. The species much stimulated by the drought, Borreria spp. and Blepharis linariifolia, did not occur in the intensively grazed pastures.The work was carried out with the assistance of M.M.A. Djittye and A. Sow, Centre National de Recherche Zootechnique Sotuba, N. Diarra, Ecole Normale Supérieure, M. Togola, Station du Sahel, and M.I. Cissé, A. Diallo, L. Diarra, M. Sidibé, G. Traoré, Centre Pédagogique Supérieur     

Identifying critical habitat for freshwater turtles: integrating long-term monitoring tools to enhance conservation and management

The effective conservation and management of threatened species requires comprehensive knowledge about resource utilisation. Here we integrated tissue stable isotope analysis and biotelemetry to identify the predominant dietary resources of two sympatric species of freshwater turtle, and locate where those items were acquired. We deployed an array of underwater acoustic telemetry receivers to autonomously, simultaneously, and continuously, monitor the movements of the threatened Elseya albagula and Elusor macrurus, over a 12-month period. Stable isotope (SI) values (δ¹³C and δ¹⁵N) were measured within the carapace of each species, and compared with SI values within potential food items. The integration of movement information and carapace SI data revealed that whilst these species had overlapping home ranges, there was less than 5% probability of inter-species dietary niche overlap. E. macrurus acquired food items consisting of bivalves, gastropods and aquatic insects within rocky riffles whilst E. albagula fed on filamentous algae and crustaceans foraged from the muddy and vegetated shallow margins of deep water pools. Our findings differ from stomach content analysis and mark-recapture studies, which reported these species to have similar habitat and resource requirements. We argue that the observed disparity is because our methods provided a weighted measure of an individual’s dietary preference and habitat utilisation over a broad time-scale, whilst stomach content analysis and mark-recapture studies offer only a single observation of an individual’s dietary preference. The research demonstrates the utility of integrating passive acoustic telemetry and carapace stable isotope analysis for identifying critical habitat for freshwater turtles.     

The invertebrate fauna of the sandstone caves of the Cape Peninsula (South Africa): patterns of endemism and conservation priorities

The temperate sandstone caves of the Cape Peninsula, South Africa, support 85 cavernicolous invertebrate species across six phyla. Six of these, including two blind and depigmented species of insects (Dermaptera) and spiders (Araneae: Hahniidae) were previously unknown. Twenty-one species are endemic to the Peninsula. Thirteen of these are presumed troglobitic Gondwanan relicts, including highly specialized, phylogenetically unique, rare species with restricted distributions and specialized habitat requirements. According to the criteria listed in the IUCN Red List Categories (1994), the onychophoran Peripatopsis alba and crustacean Spelaeogriphus lepidops should be considered Critically Endangered, their extents of occurrence being less than 100km². Furthermore, Data Deficient species, such as the freshwater shrimps Protojanira leleupi and Paramelita barnardi, the spider Hahnia sp.nov., the earwig Dermaptera sp.nov. and the centipede Cryptops stupendus, are likely to be additional Critically Endangered species on account of their exceptional rarity or restricted distributions. The remaining endemic cavernicoles are considered Endangered on account of their limited distributions (extent of occurrence <5000km²). Therefore, conservation considerations are clearly an urgent priority and appropriate recommendations are provided. Management-orientated research, long-term population monitoring and the conservation of pseudokarst areas, are urgent requirements for the conservation of these rare and threatened evolutionary relicts in their isolated island-like habitats.