Biodiversity indicators in European ground waters: towards a predictive model of stygobiotic species richness

1. Estimates of species richness obtained from exhaustive field inventories over large spatial scales are expensive and time-consuming. For this reason, efficiency demands the use of indicators as 'surrogates' of species richness. Biodiversity indicators are defined herein as a limited suite of taxonomic groups the species richness of which is correlated with the species richness of all other taxonomic groups present in the survey area.
2. Species richness in ground water was assessed at different spatial scales using data collected from six regions in Europe. In total, 375 stygobiotic species were recorded across 1157 sites and 96 aquifers. The taxonomic groups collected from more than one site and with more than two species (Oligochaeta, Gastropoda, Cyclopoida, Harpacticoida, Ostracoda, Isopoda, Amphipoda, Bathynellacea and Acari) were used to develop nonparametric models to predict stygobiotic biodiversity at the aquifer scale.
3. Pair-wise correlations between taxonomic groups were low, i.e. variation in species richness of a single taxonomic group did not usually reflect variation of the other groups. In contrast, multiple regressions calculated between species richness of any combination of taxa and extra-group species richness along the six regions resulted in a number of significant relationships.
4. These results suggest that some taxonomic groups (mainly Copepoda and Amphipoda and, to a lesser extent, Oligochaeta and Gastropoda) combined in different ways across the regions, were good biodiversity indicators in European groundwater ecosystems. However, the uneven distribution of taxonomic groups prevented selection of a common set of indicators for all six regions. Faunal differences among regions are presumably related to both historical and ecological factors, including palaeogeography, palaeoecology, geology, aquifer fragmentation and isolation, and, less clearly, anthropogenic disturbance.     

Gap-phase regeneration in a tropical montane forest: the effects of gap structure and bamboo species

To study the influence of gap structure and bamboo species on the regrowth of montane Atlantic forest, colonization by plants was characterized in 30 treefall gaps (30.3–500.5 m²). The study was conducted at Santa Virgínia (45°30 W, 23°17 S), a 4970-ha reserve of Atlantic montane forest in southeastern Brazil. Area covered by bamboos ranged from 0% to 100% of gap area. Average height of surrounding canopies ranged from 12 to 30 m. As gap are covered by bamboo and average height of surrounding canopies increased, both density and richness of pioneer woody species decreased. Density and richness of shade-tolerant species were negatively influenced by gap area. Low-light-demanding species of Miconia, Leandra and Rapanea accounted for the majority of both pioneer species and individuals sampled, whereas high-light demanding pioneers of Cecropia, Alchornea and Tibouchina were poorly represented. We suggest that in the Atlantic montane forest bamboo species compete for gaps, excluding other light-demanding pioneers. This results in an overall reduction of pioneer species richness in the Atlantic forest.     

Influence of anthropogenic disturbance on bird communities in a tropical dry forest: role of vegetation structure

A study was carried out in Sariska Tiger Reserve in India to investigate the effects of anthropogenic disturbance caused by biomass extraction on the bird communities of tropical dry forests. The study was based on comparisons of the avifaunal community as well as vegetation structure between strictly protected ('undisturbed') and intensively used ('disturbed') sites that were demarcated a priori on the basis of disturbance indicators. There was no significant difference in the number of recorded species and bird abundance between disturbed and undisturbed sites. However, bird species diversity was significantly lower in disturbed sites. Bird species composition was found to differ significantly between disturbed and undisturbed sites and was associated with the measured disturbance indicators. Changes in bird species composition occurred because of seven of 26 locally abundant bird species (26.9%) responding significantly to the disturbance regime. All the affected bird species are primarily insectivorous. Bird species composition was significantly related to six vegetation structural variables, including two that were significantly altered by disturbance. Changes in vegetation structure accounted for all the changes in bird species composition caused by disturbance. However, vegetation structure had additional effects on bird species composition besides those caused simply by disturbance. Thus, our study indicates that forest use in the form of chronic biomass extraction can have significant effects upon bird diversity and species composition of tropical dry forest. There is a need to retain a proportion of natural ecosystems as inviolate if the full complement of biodiversity is to be conserved.     

Ecology of a community of mammals in a seasonailly dry forest in Roraima, Brazilian Amazon

A community of middle-sized and larger mammals was studied in a seasonally dry forest in the far north of the Brazilian Amazon. Diurnal and nocturnal surveys were carried out through the linetransect method, in 5 different forest types along a 10-km transect. Data were collected an density, biomass, and use of the forest types, and forest strata by the mammals. The terrestrial community of mammals was more abundant than the arboreal one, with ungulates contributing to the bulk of the biomass, as a result of Maracá being highly seasonal Overall densities were lower than in other sites in the neotropics, varying from 90.2 ind/km² in mixed forest, to 159.9 ind/km² in Terra Firme forest, whereas biomass, due to the contribution of large mammals, was much higher (2613.2 kg/km² in mixed forest, and 4351.6 kg/km² in Terra Firme forest). This study confirms that the animals surviving in larger numbers in these highly seasonal forests, where food productivity may be very low during the dry season, are those that have larger home ranges and travel longer distances in search of food.     

Bat assemblage structure in two dry forests of Colombia: Composition, species richness, and relative abundance

We studied the composition, species richness, and relative abundance of bat assemblages in the Colombian dry forests of Chicamocha and Patía. In Chicamocha, 11 bats of the family Phyllostomidae were captured with mist-nets, corresponding to 85–100% of the potential phyllostomids species in the area. Two bats of the family Vespertilionidae were also captured in Chicamocha. In Patía, 12 species were captured with mist-nets, all Phyllostomidae, representing 72–100% of the estimated total number of species in the zone. Minor differences in number of species and composition were detected among sampling periods in Chicamocha. The most common species in this dry forest were Glossophaga longirostris and Sturnira lilium. In Patía, notable differences in the number of species and composition were observed among sampling periods, and the most common species were Artibeus jamaicensis, Carollia perspicillata and Phyllostomus discolor. Arid-zone dwelling bats were absent in Patía and we suggest that this absence may be associated with the isolation of Patía from other northern dry zones of Colombia since Quaternary times. There was also low abundance of bats in Patía, which appears to be related to human disturbance. The most abundant phyllostomid bat species in the two dry forests studied are those that include fruit and/or nectar-pollen from columnar cacti as an important proportion of their diets.     

Genetic structure and phylogeography of a European flagship species,the white‐tailed sea eagle Haliaeetus albicilla

We analysed 120 white‐tailed sea eagles Haliaeetus albicilla from eastern (Poland and Estonia) and southeastern (Serbian Danube population) Europe for genetic variability and structuring at the mitochondrial control region and seven nuclear microsatellite loci. We combined this new dataset with sequence and genotype data from previous analyses covering Greenland and Eurasia (total sample sizes of 420 and 186 individuals for mtDNA and microsatellites, respectively) to address the following questions: 1) does the large eastern population in Europe add significantly to the species‘ overall genetic diversity? 2) Do the new sequence data match the clinal distribution pattern (west to east) of the two major mtDNA lineages? 3) Does the preliminary hypothesis of two nuclear genetic clusters recently found in this species hold for the whole of Europe, and do these clusters show a geographic pattern? Our results confirmed Europe as a stronghold of genetic diversity in white‐tailed sea eagles, and the east of the continent contributed disproportionately to this, the reason being the admixture of eagles with different genetic background. As hypothesised, both mitochondrial lineages were recovered also in eastern Europe, but the globally more eastern lineage was dominant. The presence of two microsatellite clusters was also confirmed, and these groups, too, show a non‐random geographic distribution, with, except for Poland, a high proportion of ‘eastern‐type’ eagles in the populations of east–central and eastern Europe.     

Evaluation of a mathematical model structure describing the effect of (gel) structure on the growth of Listeria innocua, Lactococcus lactis and Salmonella Typhimurium

Aims:  To evaluate a novel secondary model structure ( Int J Food Microbiol 2008; 128: 67) that describes the effect of medium structure on the maximum specific growth rate ( μ _max) of Salmonella Typhimurium on the growth of S. Typhimurium, Listeria innocua , Lactococcus lactis and Listeria monocytogenes .
Methods and Results:  In the present study, the novel secondary model is validated for S . Typhimurium in more realistic media, namely, pasteurized milk and a cheese mimicking medium. The predictions were accurate. Next, the secondary model structure was evaluated in a two step and a global regression procedure on literature data. On the one hand, the growth of two other micro-organisms, namely L. innocua and L. lactis , in monoculture for varying gelatine concentrations was tested and on the other hand the growth rate of L. monocytogenes was fitted in a broth of which the viscosity was altered with polyvinylpyrrolidone. The model was able to describe the effect of increasing gelatine concentration or viscosity accurately.
Conclusions:  The proposed secondary model structure is able to describe the effect of gelatine concentration on the μ _max of the micro-organisms tested in this study.
Significance and Impact of the Study:  In predictive microbiology, much attention has been paid to the effect of food structure on the μ _max of bacteria. However, to the authors' knowledge, a lack of secondary models still exists to describe this effect. Although the proposed model is empirical, the model parameters have clear biological meaning. The predictive power of the model to describe the effect of food structure is clearly illustrated.     

New records of Echiura and Sipuncula in the North Atlantic Ocean, with the description of a new species of Jacobia

Data on Echiura and Sipuncula collected by the MAR-ECO expedition on the RV G.O. Sars to the northern Mid-Atlantic Ridge are presented. Eight specimens of echiuran and 13 specimens of sipunculan worms were obtained from eight stations. Two species of Echiura and two species of Sipuncula were identified. One echiuran is a new species of Jacobia.     

Regeneration of seven indigenous tree species in a dry Afromontane forest,southern Ethiopia

Regeneration of seven indigenous tree species having significant ecological and economic importance was investigated in the Munessa-Shashemene dry Afromontane forest (MSF), southern Ethiopia. Densities and distributions of seedlings, saplings and trees were assessed along gradients of altitude, light and disturbance using quadrat sizes of 10×5 m (for seedlings) and 20×20 m (saplings and trees) following line transects. The number of individuals, frequency and height of the study species were recorded in the quadrats at every 100 m drop in altitude. Seedling densities varied markedly among the species and altitudes. Mean densities (number of individuals ha⁻¹) of seedlings ranged from zero (Polyscias fulva) to 5334 (Prunus africana), and from three (Polyscias fulva) to 102 (Podocarpus falcatus) for trees and saplings. Canonical Correspondence Analysis revealed that seedlings of Celtis africana and Croton macrostachyus were highly favored by disturbance and, hence, were concentrated in canopy gaps within the forest. Based on their population structures, the study species could be categorized into three groups: (1) Species that showed the highest proportion of individuals in the lowest height class and with a gradual decrease towards the upper height classes, which suggests good regeneration; Podocarpus falcatus, C. africana, C. macrostachys and P. africana belonged to this group. (2) Species that showed higher proportions of individuals in the lowest height class and with missing individuals in the subsequent middle height classes, indicative of hampered regeneration; Syzygium guineense and Pouteria adolfi-friederici belonged to this group. (3) Species with no individuals in the lowest and middle height classes but represented by individuals in upper height classes; P. fulva belonged to this group. The species categorized in the last two groups exhibited hampered regeneration, and P. fulva is in the verge of local extermination. High seedling densities (e.g. C. africana and P. africana) and/or adaptive defense mechanisms to herbivory (e.g. P. falcatus and C. macrostachyus) were common attributes of species, which exhibited good regeneration. Regeneration problems were largely attributed to human disturbance, lack of suitable habitat for seed germination or problems associated to seed set (seed predation or abortion). Our study indicated that P. fulva, P. adolfi-friederici and S. guineense require the highest immediate attention for conservation in the MSF.     

Regeneration patterns in a Central European dry heathland: effects of burning,sod-cutting and cutting

Vegetation development in dry heathlands was studied during a six-year period following experimental burning, sod-cutting and cutting in a continental area in the southern part of the Czech Republic (Podyjí National Park). Calluna vulgaris-dominated heathlands in the area were composed of uneven-aged stands and had been unmanaged for several decades. The aim of the study was testing the applicability of Western European management systems to nature conservation in a continental area. Species composition was recorded in 8 permanent plots using 25×25 cm grids, and vegetation recovery following different treatments was analysed. Calluna recovered successfully after burning. Burning dense heathlands, which contained a large amount of woody fuel, resulted in a medium-intensity fire that destroyed moss mats and litter and exposed patches of bare ground to facilitate Calluna regeneration by seed, in addition to vegetative regrowth. On the contrary, in open heathlands with patches of herbaceous vegetation, low-intensity fires which failed to expose mineral soil were more typical. Almost all Calluna regeneration was vegetative in this case, and regrowth was slower. Heathland recovery after sod-cutting to mineral soil depended on whether or not Calluna seed germination occurred in the plot. With germination, the community developed towards heathland; without towards grassland. Cutting promoted a striking increase in grass cover, which was followed by the slow recovery of Calluna. The experiments suggest that of these management systems, burning is perhaps the most appropriate in the study area. A nature conservation management system is proposed, based on sheep grazing combined with rotational burning of restricted patches.     

Description of a new Brazilian species of Mycodrosophila (Diptera,Drosophilidae) with emphasis on the morphology of phallic sclerites

Mycodrosophila is a cosmopolitan genus of Drosophilidae that comprises approximately 130 species with mycophagous habitats. In this study, we described a new species of Mycodrosophila based on morphological traits and included details of the male terminalia. The holotype is from Eugênio Lefévre, locality in Campos do Jordão municipality, SP, Brazil, located in the Atlantic rainforest biome and was sampled in the 1930s.     

Effects of population density on forest structure and species richness and diversity of trees in Kampong Thom Province, Cambodia

This study examined differences in stand structure, tree species richness, and tree species diversity in relation to population density in Kampong Thom Province, Cambodia. Tree data were obtained from a 1997 forest inventory involving 60 clusters (540 plots) systematically distributed over 30% of the provincial forest area. Spatially referenced population data were obtained from the 1998 national population census. The average number of trees per cluster was 356/ha, the average basal area, 23 m²/ha, the average stand volume, 217 m³/ha, and the average aboveground biomass, 273 Mg/ha for all trees of DBH 10 cm and larger. The average species richness per cluster was 37 species, while average species diversity was measured as 0.916 using Simpson’s index and 2.98 by Shannon’s index. Significant negative correlations were generally found between population density surrounding clusters and tree density, basal area, stand volume, aboveground biomass, and species richness and diversity for three examined diameter classes (DBH of 10–30, ≥30, and ≥10 cm). As the distance from clusters for calculating population density increased, the correlation levels increased up to 5 or 7 km, depending on the variables and diameter class, and then stayed relatively constant for stand structure variables and decreased for species richness and diversity. The results indicate that evidence of disturbance was more pronounced at higher population density up to around 5 to 7 km. We suggest that introduction of greater controls on human disturbance should be a high priority for resource management and conservation in Kampong Thom Province and, presumably, Cambodia as a whole.     

Reproductive system and fitness of Vriesea friburgensis,a self‐sterile bromeliad species

Reproductive biology and plant fertility are directly related to many aspects of plant evolution and conservation biology. Vriesea friburgensis is an epiphytic and terrestrial bromeliad endemic to the Brazilian Atlantic rainforest. Hand‐pollination experiments were used to examine the reproductive system in a wild population of V. friburgensis. Plant fertility was assigned considering flower production, fruit and seed set, seed germination, and pollen viability. Self‐sterility observed from spontaneous selfing and manual self‐pollination treatments may be the consequence of late‐acting self‐incompatibility. Hand‐pollination results indicated no pollen limitation in the population studied. Floral biology features such as a few daily open flowers, nectar production, and sugar concentration corroborate hummingbirds as effective pollinators, although bees were also documented as pollinators. Components of fitness such as high flower, fruit, and seed production together with high seed and pollen viability indicate that this wild population is viable. From a conservation point of view, we highlight that this self‐sterile species depends on pollinator services to maintain its population fitness and viability through cross‐pollination. Currently, pollinators are not limited in this population of V. friburgensis. Conversely, the maintenance and continuous conservation of this community is essential for preserving this plant–pollinator mutualism.     

The influence of sea currents, past disruption of gene flow and species biology on the phylogeographical structure of coastal flowering plants

Aim We investigate the geographical genetic structure of two coastal plant species, Cakile maritima Scop. (Brassicaceae) and Eryngium maritimum L. (Apiaceae), through three sea straits and along one continuous stretch of coast using amplified fragment length polymorphisms (AFLPs). The two species have a similar ecology in that they grow in sandy habitats, but differ in life‐form (annual vs. perennial) and dispersability of seeds by sea water as inferred from floating experiments. The sea straits differ in their geological history and their modern current systems. The primary goal of our study was to test the hypothesis that sea straits have an influence on the geographical patterns of genetic variation at the population level. Location The areas around the Strait of Gibraltar, the Dardanelles, the Bosporus and the Atlantic coast of western France. Methods For both species we investigated AFLP variation in several populations from each area. Bayesian clustering and diversity and differentiation measures were used to analyse the genetic data. Results In most areas the spatial genetic structure was similar between the two species. They share the presence of distinct genetic gaps along the coast through the Strait of Gibraltar and the Bosporus, and these genetic gaps coincide with the straits. Both species show genetic continuity along the coast of western France. A distinct genetic gap was found through the Dardanelles for C. maritima but not for E. maritimum. Main conclusions The study shows that sea straits have an influence on the geographical patterns of genetic variation. Sea currents are inferred to cause the genetic gap through the Strait of Gibraltar. In the Bosporus and, for C. maritima, through the Dardanelles, the genetic gaps found are explained by the past closure of these two straits as well as by present‐day factors. Simulations indicate that the lower differentiation of C. maritima through the Dardanelles than through the Bosporus cannot be explained by the difference in geological history of these two straits. The difference in seed dispersability between the two species is argued to be responsible for the observation that differentiation among genetic clusters is higher in E. maritimum than in C. maritima where a direct comparison is possible.     

Martiodendron fluminense (Leguminosae, Caesalpinioideae), a new species from the Atlantic coast rainforest of Brazil

A new species of Leguminosae is described and illustrated:Martiodendron fluminense, the southernmost and the only species of the genus to occur in the Atlantic forests of southeastern Brazil.     

Matelea sartago-diaboli, a new species of Apocynaceae: Asclepiadoideae from the inter-Andean dry valleys of Bolivia

Summary   Matelea sartago-diaboli is described from the Río Grande inter-Andean dry valley system of central Bolivia, and compared with the recently described Argentinian endemic M. calchaquina. The new species is illustrated, and its conservation status discussed.     

Comments on the Atlantic species of the genus Evermannella (Scopelomorpha, Aulopiformes, Evermannellidae) with a re–evaluation of the status of Evermannella melanoderma

Examination of the alimentary canal of specimens of the genus Evermannella of the form previously referred to the circumglobal species E. indica Brauer, 1906 has revealed differences between specimens from the Atlantic Ocean and those caught in the Indian and Pacific Oceans. On the basis of gut morphology and skin pigmentation the Atlantic species E. melanoderma Parr, 1928 is distinguished from the Indo–Pacific E. indica . Some observations are presented on the size structure of the E. melanoderma population off Madeira.     

Physical variables driving epiphytic algal biomass in a dense macrophyte bed of the St. Lawrence River (Quebec, Canada)

The variables affecting epiphyton biomass were examined in a sheltered, multispecies macrophyte bed in the St. Lawrence River. Alteration of light penetration, resulting from the presence of dense macrophytes forming a thick subsurface canopy, primarily determined epiphyton biomass. Seasonal decrease of water levels also coincided with major increases in biomass. Plant morphology was the next important variable influencing epiphytic biomass, whereas the contribution of other variables (sampling depth, macrophyte species, relative abundance of macrophytes, and temperature) was low. Groups of lowest epiphyte biomass (0.1–0.6 mg Chla g^–1 DW) were defined by the combination of a low percentage of incident light (<13% surface light) and simple macrophyte stem types found below the macrophyte canopy. Highest epiphyte biomass (0.7–1.8 mg Chla g^–1 DW) corresponded to samples collected in mid-July and August, under high irradiance (>20% surface light) and supported by ramified stems. Our results suggest that epiphyton sampling should be stratified according to the fraction of surface light intensity, macrophyte architecture, and seasonal water level variations, in decreasing order of influence.     

Evolution of temperature and salt structure of Lake Bonney, a chemically stratified Antarctic lake

A resurgence of interest in the ecology of perennially ice-covered lakes in the McMurdo dry valleys has necessitated a review of our knowledge of the physical and chemical properties of these unusual lakes. Salinities in the ice-covered lakes cover a range from freshwater to hypersaline brines. Recent measurements of salt composition and concentrations in Lake Bonney reveal little change below the chemocline since extensive measurements made in 1960–1961, although lake level has risen by approximately 5 m since that time. The rise in lake level has resulted in a thickening of the freshwater layer above the chemocline. Temperature structure has adjusted to the effects of increased lake level on heat transfer processes such as transmission and absorption of solar radiation in the water column.Questions about how water-column stability affects biology in Lake Bonney have motivated the formulation of a method to compute density from in situ measurements of temperature, conductivity and pressure. Owing to high salt concentration and unique ion ratios, we modified the UNESCO Equation of State for seawater to predict density at salinities greater than 42. The modifications merge smoothly with the UNESCO equations at a salinity of 42. At salinities below 42 the UNESCO equations give excellent predictions of density.     

Dolichopteryx rostrata, a new species of spookfish (Argentinoidea: Opisthoproctidae) from the eastern North Atlantic Ocean

A new species, Dolichopteryx rostrata, is described on the basis of a single specimen (66.2 mm in standard length) collected west of the Hebrides Islands, eastern North Atlantic Ocean. The new species is characterized by an elongate snout and head, small pouchlike eyes, an adipose fin, short dorsal fin base, anal fin base originating under dorsal fin base, a clear longitudinal suborbital brownish band extending forward from behind posterior margin of orbit to snout tip, and 41 (=26 + 15) vertebrae. Total fecundity is low; the ovarian eggs number only 473, despite the ovary having developed ova. Ovarian eggs could be clearly subdivided into an “undeveloped group” (0.1–0.7 mm diameter classes, n = 405) and a “developed group” (0.9–1.3 mm classes, n = 68), based on their frequency distribution. Supplementary material to this paper is available in electronic format at http://dx.doi.org/10.1007/s10228-005-0306-2