Recent Distribution Patterns Research Articles

Precipitation and temperature primarily determine the reptile distributions in China

Reptiles make up one‐third of tetrapods, however they are often omitted from global conservation analyses. Understanding the determinants of reptile distribution is the foundation for reptile conservation research. We assembled a dataset on the distribution of 231 reptile species (nearly 50% of recorded species in China). We then investigated the association of species range filling (the proportion of observed ranges compared to species potential climate distributions) with climate, range size, topography and human activity, using three regression methods. At the species level, we found the most primary factors influencing the recent distribution pattern of reptiles across China were the mean annual precipitation (MAP) and the mean annual temperature (MAT). In contrast, human activity came in last. Similarly, at a spatial level, MAP and MAT were still the most important factors. Geographically, the south and east of China support the highest reptile diversity, partially due to high precipitation. Contrary to the prevailing notion that reptile distributions are primarily shaped by human activities, our study re‐emphasizes the importance of climate in determining reptile distribution. It accentuates the necessity of integrating climate variables into future animal conservation strategies in China. Our findings also offer valuable insights for informing conservation practices, including the site planning of natural reserves and national parks, as well as monitoring of environmental factors in protected areas.

Causative factors influencing epizoochorous dispersal of weed seeds by sheep and associated carcass contamination in southern Australia

AbstractHordeum spp. (barley grass) and Bromus spp. (brome grass) are annual weed species that achieve long‐distance seed dispersal via attachment to sheep, but also lead to sheep carcass damage due to the penetration of seeds into animal tissues. Range expansion of invasive weed populations predicted as a consequence of climate change may be associated with an increase in seed contamination incidence globally. An examination of Australian abattoir data (2006–2012), along with recent weed distribution patterns, indicates carcass contamination was associated with rainfall and abundance of key annual grass weeds, primarily Bromus spp. and Hordeum spp., although other factors may play a contributing role. Significant differences in seed contamination in slaughtered sheep were noted between states and regions, with widespread contamination occurring throughout all agro‐ecological zones. Abattoir, sheep age and sex significantly influenced incidence, with contamination highest in adult males. Incidence increased with mean monthly rainfall, but declined with mean elevation, and significant interactions were noted between mean monthly temperature and state, and between mean elevation and year. Results show the need for vigilant recording of seed injuries in sheep to enhance weed surveillance efforts and effective integrated weed management of contributing annual grass weeds.

Magnitude and influence of atmospheric phosphorus deposition on the southern Baltic Sea coast over 23\xa0years: implications for coastal waters

BackgroundThere are various ways for nutrients to enter aquatic ecosystems causing eutrophication. Phosphorus deposition through precipitation can be one pathway, besides point sources, like rivers, and diffuse runoff from land. It is also important to evaluate recent trends and seasonal distribution patterns of phosphorus deposition, as important diffuse source. Therefore, a long-term dataset was analysed including 23 years of daily phosphate bulk depositional rates and 4.5 years of total phosphorus (TP) bulk depositional rates. The study area was at the coastline of the southern Baltic Sea, an area which shows severe eutrophication problems.ResultsThe median daily deposition of phosphate was 56 µg m−2 day−1 (1.8 µmol m−2 day−1) at 4222 rain events. The median annual sum of phosphate deposition was 16.7 kg km−2 a−1, which is comparable to other European areas. The annual TP deposition depended strongly on methodological aspects, especially the sample volume. The median TP-depositional rates ranged between 19 and 70 kg km−2 a−1 depending on the calculated compensation for missing values, as not every rain event could be measured for TP. The highest TP-depositional rates were measured during summer (e.g. up to 9 kg TP km−2 in August 2016). There was no trend detectable for phosphate- and TP-depositional rates over the sampled period.ConclusionsDeposition of P is a considerable nutrient flux for coastal waterbodies. Median total annual deposition contributed 3 t (phosphate) to 10 t (TP) per year into the adjacent lagoon system, being therefore close to annual riverine inflows of 10 t phosphate and 20 t TP per year. However, the impact of precipitation is predicted to be higher in lagoon parts with fewer point sources for phosphorus, if equally distributed over the area of interest.

Recent status and distribution pattern of cotton leaf curl disease in Northwest India: an alarming situation in future cotton cultivation

A survey was made to study cotton leaf curl disease (CLCuD) incidence in cotton growing areas of Haryana, Punjab and Rajasthan in Northwest (NW) India during the years of 2013 and 2014. The present study revealed higher overall CLCuD incidence of 77.5% with higher overall boll number reduction (BNR) of 36.9% in 2013 compared to incidence of 49.6% with 7.6% BNR in 2014 in Haryana. In Rajasthan the disease incidence of 55.9% and 21.6% BNR in 2013 when compared to 10.8% of incidence and 2.9% BNR in 2014 was recorded. The overall CLCuD incidence and BNR in cotton growing areas of Punjab were more or less similar for both the years of 2013 and 2014, where disease incidence of 54.1% with BNR 14.6% in 2013 and disease incidence 57.8% with BNR of 15.9% in 2014 was recorded. All the 11 Bt-cotton hybrids from the farmer’s fields of Sri Ganganagar and Sirsa districts surveyed were highly susceptible to CLCuD in both the years; showing 100% disease incidence with BNR of 32.3-82.3% in 2013 and 49.2-100% with BNR of 8.7-17.4% in 2014. Infectivity study through whitefly (Bemisia tabaci) and polymerase chain reaction (PCR) of ORF V1 (CP gene) determined that CLCuD in NW India is caused by whitefly transmitted CLCuD-begomoviruses. Sequence analysis of CP gene indicated that at least three CLCuD-begomoviruses variants appeared in this cotton growing region. The increased CLCuD incidence with huge yield loss and occurrence of CLCuD-begomovirus variants reported in the present is an alarming situation for the profitable cultivation of cotton in north India.

Non-native fish species in Hungarian waters: historical overview, potential sources and recent trends in their distribution

Due to its central position in the Danube basin and its considerable fishery sector, Hungary plays a key role in the spread of non-native fish species in Europe. Nevertheless, the status of non-native fish has not yet been reviewed for Hungary. Therefore, our aims were (1) to give a comprehensive historical overview regarding the occurrence of non-native fish species of Hungary, (2) to show their recent distribution patterns using GIS, and (3) to evaluate the importance of the possible drivers in their spread. Literature data show 59 non-native fish species from Hungary. The appearance of new species—mostly due to aquarium fish releases—shows an accelerating trend nowadays. Although non-native fish have appeared at 78.7% of the studied 767 sites during our recent countrywide survey, their distribution was uneven. Lowland streams, lowland rivers, and the River Danube were the most affected by non-native fish, particularly the gibel carp, topmouth gudgeon and pumpkinseed escaped from fish/angling ponds, and the recent invasion of Ponto-Caspian gobies. Our results indicated that in order to reduce the effects and intensity of further invasions, more rigorous control of aquarium trade, angling pond stockings, and inter-watershed fish transports are necessary.

Historical review of American crocodiles (Crocodylus acutus) along the Florida Gulf Coast

In this paper, I review historic and recent geographic distribution patterns of Crocodylus acutus in Florida, USA. I summarize reasons for the historical decline of its population in North America between 1930 and 1970. Major causes include hunting for the hide industry, pet trade, wildlife exhibitions, habitat loss, and road kills after 1938 when voluminous motor vehicle traffic was first introduced into their habitat. Individuals and groups of C. acutus became established along the coast of Southwest Florida over more than an 80-year period, but not to the habitat’s potential carrying capacity because of human interference. Recent changes in its distribution pattern suggest continual dispersal into Southwest Florida and the Florida Keys because of climate change and alteration of the population’s primary sites in South and Southeast Florida. Habitat destruction, because of dredge and fill development in the region’s coastal zone followed by an increasing human population, has limited successful dispersal and growth of the C. acutus population along the Gulf of Mexico in Southwest Florida. Recent occurrences of C. acutus in the region (excluding questionable inland sightings) extend its northernmost range to the northern end of Lake Tarpon in Pinellas County. Climate change may provide temperatures that allow C. acutus extension of its range northward along Florida’s southwest coast.

A vanishing hotspot—the impact of molecular insights on the diversity of Central European Bythiospeum Bourguignat, 1882 (Mollusca: Gastropoda: Truncatelloidea)

The current study investigates the Central European groundwater snails of the genus Bythiospeum which are currently regarded as highly diverse with a hotspot in south-western Germany coupled with high rates of endemism. This systematic concept combined with the fragility of their habitat results in a high rate of threatened species (76–96 %). The analyses of the mitochondrial COI fragment of nearly 200 specimens from 35 localities in Germany, Switzerland and marginally Austria and France including type localities of 14 taxa revealed five well-distinguished clades with genetic distances from 3.6 to 16.4 % while variability within clades and populations is very low. Morphological investigations focused on parts of the reproductive systems showed rather great uniformity with only minor differences in penis shape, size and localisation. Previous species concepts based on conchology and morphology do not correspond to the current results, and shell shape is suspected as poor indicator for species delineation. Our data indicate a significantly lower diversity in Central Europe, e.g. only three species occurring in Germany instead of 25. Taxonomic implications of our hypothesis are given and discussed. Accordingly, most of the German populations belong to Bythiospeum acicula (Held, 1838) while B. husmanni (C. R. Boettger, 1963) is a very restricted relict. In comparison with other groundwater organisms, two of the more northerly distributed species show a large range stretching over at least 410 or 490 km respectively. Post-glacial re-colonisation from refugia is discussed as most likely explanation of the recent distribution pattern.

Population Genetic Patterns of Threatened European Mudminnow (Umbra krameri Walbaum, 1792) in a Fragmented Landscape: Implications for Conservation Management.

The European mudminnow (Umbra krameri) is a Middle Danubian endemic fish species, which is characterised by isolated populations living mainly in artificial habitats in the centre of its range, in the Carpathian Basin. For their long term preservation, reliable information is needed about the structure of stocks and the level of isolation. The recent distribution pattern, and the population genetic structure within and among regions were investigated to designate the Evolutionary Significant, Conservation and Management Units (ESUs, CUs, MUs) and to explore the conservation biological value of the shrinking populations. In total, eight microsatellite loci were studied in 404 specimens originating from eight regions. The results revealed a pronounced population structure, where strictly limited gene flow was detected among regions, as well as various strengths of connections within regions. Following the results of hierarchical structure analyses, two ESUs were supposed in the Carpathian Basin, corresponding to the Danube and Tisza catchments. Our results recommend designating the borders of CUs in an 80–90km range and 16 clusters should be set up as MUs for the 33 investigated populations. How these genetic findings can be used to better allocate conservation resources for the long term maintenance of the metapopulation structure of this threathened endemic fish is discussed.

Quantifying the activity levels and behavioural responses of butterfly species to habitat boundaries

1. The ability of species' to undergo climate‐driven range shifts across fragmented landscapes depends on their dispersal ability as well as the structure of the landscape. For species' range shifts to occur, individuals must first leave suitable habitat to seek new habitat; this is likely to depend on the rate of movement of individuals within habitat and the likelihood that a boundary is crossed, once it is encountered. For three species of butterfly with contrasting histories of recent range expansion, we examined the propensity of individuals to move within a habitat and their responses to habitat boundaries.2. We quantified the extent to which Plebejus argus (Linnaeus) (a declining habitat specialist), Aricia agestis (Schiffermuller) (an expanding generalist) and Polymmatus icarus (Rottemburg) (a geographically ubiquitous generalist) crossed habitat boundaries into unsuitable habitat and moved within suitable habitat. The observed movement was then related to individual and environmental conditions.3. Species differed in their activity levels in accordance within their recent distribution patterns (P. icarus > A. agestis > P. argus). Our results for P. argus suggest that movement may be motivated by nectar‐seeking, and that males generally move more than females. All three species tended to avoid crossing habitat boundaries; however the proportion of individuals crossing habitat boundaries did not differ significantly among species.4. We conclude that levels of activity within a habitat, which will affect the frequency with which individuals encounter habitat boundaries, rather than behavioural responses to the boundaries, may be important drivers of distribution change.

Comparison of Historical and Recent Fish Distribution Patterns in Oklahoma and Western Arkansas

In the past century and a half, surface waters in the lower Great Plains have been impacted by numerous factors related to human settlement and development of the region including construction of reservoirs, which have been well documented to have negative effects on stream fish communities. In Oklahoma, by 1925 there were only seven artificial impoundments (of 36–970 hectares), but by 2007 there were 146 impoundments in the state lake registry ranging up to 42,000 hectares. Most were built from the 1930s to the 1970s. We examined historic and recent distribution patterns of fishes in Oklahoma and western Arkansas using data from 86 collections made by A. I. Ortenburger from 1925–1927 and from 381 collections we made from 1975–2009 in the same region, to ask if faunal changes were apparent following the era of dam construction. Although exact sites in the 1920s and in 1975–2009 were not identical, there were collections in 14 Hydrologic Units (HUCs as identified by eight-digit Hydrologic Unit Codes) in th...

Stygobiont polychaetes: notes on the morphology and the origins of groundwater <italic>Namanereis</italic> (Annelida: Nereididae: Namanereidinae), with a description of two new species

More than half of the species in Namanereis Chamberlin, 1919 (Nereididae: Namanereidinae), are adapted to life in subterranean waters. We document the taxonomy, distribution, and adaptations of the groundwater-inhabiting species in this genus for the first time, starting from the description of two new stygobitic species. The first, Namanereis pilbarensis sp. nov. from water-table carbonate deposits in the Pilbara region of north-west Australia, is representing the first record of a stygobitic polychaete from Australia, and the second, Namanereis socotrensis sp. nov., from karstic groundwater on Socotra Island (Yemen) is the second stygobitic Namanereis species from Socotra. Troglomorphic adaptations observed include the absence (or reduction) of eyes and cuticular pigment, and cirriform appendages of the head, parapodia, and pygidium that are all considerably longer than in their marine counterparts. The chaetae and jaws differ in some groundwater species but not others, so the troglomorphic nature of these features is less certain. Remarkably, the two species of the Socotra Archipelago (Namanereis gesae Fiege & Van Damme, 2002, from Abd al Kuri and the new species) seem to derive from different ancestors, respectively single terminal tooth and bifid tooth-jawed lineages. Based on the jaw morphologies, we suggest that the groundwater polychaetes of this genus might not have entered groundwater from freshwater/anchialine habitats during a single colonization event, as previously suggested, but at different times. Different geographical origins of two groups of species (Gondwanan and Tethyan) are suggested based on recent distribution patterns. © 2014 The Linnean Society of London

Stygobiont polychaetes: notes on the morphology and the origins of groundwaterNamanereis(Annelida: Nereididae: Namanereidinae), with a description of two new species

More than half of the species in Namanereis Chamberlin, 1919 (Nereididae: Namanereidinae), are adapted to life in subterranean waters. We document the taxonomy, distribution, and adaptations of the groundwater-inhabiting species in this genus for the first time, starting from the description of two new stygobitic species. The first, Namanereis pilbarensis sp. nov. from water-table carbonate deposits in the Pilbara region of north-west Australia, is representing the first record of a stygobitic polychaete from Australia, and the second, Namanereis socotrensis sp. nov., from karstic groundwater on Socotra Island (Yemen) is the second stygobitic Namanereis species from Socotra. Troglomorphic adaptations observed include the absence (or reduction) of eyes and cuticular pigment, and cirriform appendages of the head, parapodia, and pygidium that are all considerably longer than in their marine counterparts. The chaetae and jaws differ in some groundwater species but not others, so the troglomorphic nature of these features is less certain. Remarkably, the two species of the Socotra Archipelago (Namanereis gesae Fiege & Van Damme, 2002, from Abd al Kuri and the new species) seem to derive from different ancestors, respectively single terminal tooth and bifid tooth-jawed lineages. Based on the jaw morphologies, we suggest that the groundwater polychaetes of this genus might not have entered groundwater from freshwater/anchialine habitats during a single colonization event, as previously suggested, but at different times. Different geographical origins of two groups of species (Gondwanan and Tethyan) are suggested based on recent distribution patterns. © 2014 The Linnean Society of London

Distribution patterns of Yangtze finless porpoises in the Yangtze River: implications for reserve management

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is a highly threatened cetacean endemic to the middle and lower reaches of the Yangtze River that has suffered a dramatic decline in recent decades. We characterize and quantify recent distribution patterns of porpoises in the Yangtze River in order to facilitate strategic management of existing in situ cetacean reserves and maximize effective utilization of limited conservation resources. We calculated porpoise relative abundance (encounter rate) using a 1-km moving average along the Yangtze main stem based on a combined visual and acoustic survey conducted in 2006. We then evaluated conservation priority areas based on encounter rates along the river. High-porpoise density areas (>0.20porpoiseskm(-1)) cover approximately one-third (33.9%, 599km) of the survey area and contain approximately two-thirds of the porpoise population, making them priority areas for porpoise conservation. In contrast, low-porpoise density areas (0.05porpoiseskm(-1)) cover 28.8% (509km) of the survey area but contain only 4.5% of the porpoise population, and may already be of little value for porpoise conservation. Five high-priority porpoise conservation sites and five sections that now contain few or no surviving porpoises are identified. Proposed spatial modifications to existing reserves and associated conservation recommendations are made for five existing protected areas along the Yangtze main stem, and we emphasize that some additional river sections should urgently be designated as new protected areas given their high porpoise density. Our approach for identifying conservation priorities may provide lessons for reserve design and management in other protected area networks.

Effect of wetland reclamation and tillage conversion on accumulation and distribution of phthalate esters residues in soils

Accumulation and distribution of phthalate esters (PAEs) in the soils of natural and reclaimed wetlands for different cultivation purposes were investigated. The selected reclaimed soils have only been under cultivation since 1995, thus the behaviors of PAEs may precisely reveal their recent distribution patterns. Dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) were all detected in surface soil samples. The vertical distribution of PAEs differed between the natural wetlands and cultivated fields. The concentration of PAEs in wetland soil decreased from 0cm to 30cm, and then increased from 30cm to 40cm soil depth. However, the concentrations in 3 types of cultivated fields consistently increased from 0cm to 40cm soil depths. The total concentration of DMP, DEP, DnBP, and DEHP in the wetland surface soil was 109.2ng/g. The total concentrations in rice fields tended to be higher than that of the wetland soil although the difference was not statistically significant, most likely due to the short tillage history. The conversion of bean field to rice field has had a significant effect on accumulation of PAEs. The total concentrations of PAEs in the 1-year rice field were significantly higher than that in the bean field. This was partly due to differences in pesticide and fertilizer usage between rice and bean cultivations; slower biodegradation, abiotic degradation, and evaporation behavior resulting from water covering of rice field probably also contributed to the higher PAEs concentrations in the rice field.

Micro-site conditions of epiphytic orchids in a human impact gradient in Kathmandu valley, Nepal

We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, with respect to (i) the micro-site conditions and (ii) the type and intensity of land use. The occurrence of epiphytic orchids was recorded for a grid with 1.5 km cell size. The cells represent different types and intensities of human impact. Site factors such as bark rugosity, bark pH, diameter at breast height (dbh; 1.3 m) of host trees, exposure to wind and sunlight intensity were recorded. With regard to the species richness and abundance of epiphytic orchids, we compared different human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used for a supervised classification of land cover. Ficus religiosa turned out to be the most important host species for orchids in urban areas, while Schima wallichii and Alnus nepalensis significantly host orchids in the other categories. Both species richness and abundance of epiphytic orchids were significantly higher under very low human impact (forest in national park) and also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid populations. Host bark pH, bark rugosity, sunlight intensity and host exposure were significantly different for all human impact categories in order to harbour epiphytic orchid species. Habitats with a mixture of mature trees are suitable and essential for the conservation of viable populations of epiphytic orchids in settled areas. The study reveals that to improve the population size of orchids it is essential for future urban forestry to: (i) Protect old trees as carriers of existing epiphytic orchid diversity, (ii) protect medium old trees to ensure that they may become old trees, (iii) plant new host trees for the future, (iv) plant in groups instead of single isolate trees. Trees should especially be planted in areas where orchids still exist to provide more trees for orchid population enlargement (e.g. along riparian system). Native species should be favoured; the pool of such native host species is wide.

Testing a relict distributional pattern of fen plant and terrestrial snail species at the Holocene scale: a null model approach

Aim The term relict refers to a formerly widespread species currently occurring in refugia that provide a persistent combination of specific ecological conditions. In peatlands, direct palaeoecological evidence of relict status exists for some plant species and, in the case of calcareous sediments, for some snail species. We tested whether some species are significantly linked to old calcareous fens at the millennial scale independent of the effect of recent fen area. We focused on three organism groups – vascular plants, bryophytes and land snails – that differ in the degree of preservation of their remains in calcareous fen sediments and in their dispersal ability. Location Western Carpathians (Slovakia and the Czech Republic). Methods The sample sites comprised 47 well-preserved calcareous fens, from which we compiled complete recent species lists, measured the area and analysed radiocarbon-dated samples from the deepest sediment and from the beginning of complete deforestation, as indicated by plant and snail fossils. Using the species co-occurrences in large data sets, we identified calcareous fen specialists and compared their recent distribution patterns against a null model that controlled for the effect of fen area. Results Two land snail species, eleven vascular plant species and no bryophyte species have statistically significant affinities with old fens, independent of the effect of recent fen area. For one bryophyte and one snail, the effects of age and area are not distinguishable. Main conclusions The results for land snails, being abundantly preserved and easily determinable in calcareous fen deposits, are in full accordance with the direct macrofossil evidence. This suggests that our approach indirectly revealed a relict distribution of the species. Identification of species that are significantly linked to ancient localities at the millennial scale has great potential in palaeoecology for the detection of stands with old sediments, and in nature conservation as a tool for the identification of long-term-persisting rare species that infrequently colonize young sites and thus deserve priority in the protection of their habitats. From a theoretical perspective, limited dispersal from old to new localities of the same habitat can contribute to spatial effects in biotic assemblages, even at relatively fine scales.

From Porto to Portadown: Portuguese workers in Northern Ireland's labour market

While North-Western Europe remains the principal destination for Portuguese emigrants, post-millennium flow has seen the United Kingdom (UK) and Northern Ireland (NI), in particular, emerging as a focal point. As part of a changing labour market demand and supply process, several thousand migrants have now been recruited by agencies to work in the region's rurally based food processing industries. This article quantifies the resurgence of Portuguese emigration trails, explores their recent distribution patterns, and evaluates the role of employment intermediaries in facilitating the flow. Using qualitative discursive techniques the experiences of these players are examined before determining their impacts on the local labour market. Results show that benefits have been brought to a number of localised economies suffering from shortages and working patterns based on substitution and segmentation have been fundamentally altered. At the same time, some small towns have struggled to adapt to this influx and concerns have been raised in relation to work-based problems and the pace of developmental change associated with the growing numbers of Portuguese emigrants in Northern Ireland.

Late Glacial to Recent distribution pattern of deep-water Uvigerina species in the north-eastern Atlantic

Phases with massive abundances of Uvigerina species recorded in North Atlantic deep-sea cores were previously attributed to water mass properties or to extended high productivity during the last Glacial. We investigated the Uvigerina distribution in 53 sediment cores and 555 surface samples from the north-eastern Atlantic ranging from 30° to 70°N and 1 to 4410 m water depth. Our results showed that Uvigerina pigmea dominated in late Pleistocene assemblages whereas Uvigerina peregrina and Uvigerina peregrina parva were common during the Holocene. Uvigerina pigmea lives today in the Gulf of Guinea and South Atlantic only (9°N to 17°S), but was present up to 54°N during the Last Glacial Maximum. The species retreated north- and southwards during Termination I and disappeared in the north-eastern Atlantic off northern Portugal 6100 years ago. Uvigerina peregrina and U. peregrina parva spread out from isolated occurrences along the continental slope off western Iberia at the onset of Termination I. Uvigerina peregrina exhibited Recent abundance maxima at Goban Spur, Plateau des Landes, and the Iberian Margin. These areas are subjected to strong lateral advection by downslope transport and sediment focusing. The actual flux rate of particulate organic matter is locally raised by a factor of 4 to 5. Comparable flux rates were otherwise recorded at U. peregrina maxima under the NW-African coastal upwelling regime. The Recent distribution of U. pigmea and evidence from sediment cores show an organic carbon flux of 3.5 g C m − 2 yr − 1 as minimum for a sustainable population of this species. Alkenone, pigment and planktonic foraminiferal records from cores MD952039 and MD952040 revealed that a spring bloom dominated productivity dynamics and a balanced food particle composition of haptophyteae algae and diatoms were limiting environmental factors for U. pigmea during the Pleistocene. A widespread change from glacial to modern productivity characteristics during the last Deglaciation may have triggered the early Holocene disappearance of U. pigmea from the north-eastern Atlantic.

Calcareous dinoflagellate cysts in South and equatorial Atlantic surface sediments: diversity, distribution, ecology and potential for palaeoenvironmental reconstruction

Several marine, peridiniphycidean dinoflagellate species produce calcareous cysts during their life cycle, which are relatively resistant to chemical and physical degradation and are therefore often found in large quantities in oceanic bottom sediments. Although the use of these calcareous cysts as proxies for palaeoenvironmental and palaeoclimatic reconstructions has seen many advances over the last decade, until now only relatively patchy and regional information was available on their recent distribution patterns and ecology, especially at the species level. In this paper, comprehensive calcareous cyst diversity and distribution data have been compiled from published and unpublished work for 167 South and equatorial Atlantic Ocean surface sediments, ranging from 20°N to 50°S, and 30°E to 65°W. The main aim has been to focus on the complex, often non-linear, relationships between individual species’ distributions and the physicochemical and trophic conditions of the overlying (sub)surface waters through the use of x–y graphs of cyst abundance vs. (sub)surface water environmental parameters, and detrended correspondence analyses. Ten cyst species and the calcareous vegetative coccoid species Thoracosphaera heimii were observed in the bottom sediments, each species showing its own characteristic distribution pattern in relation to the environmental conditions of the upper water masses above them (e.g. sea surface temperature, productivity, stratification). The sensitive reactions of various species to unique combinations of environmental parameters shows that each species has its own specific ecological traits, thus rejecting the bundled use of ‘calcareous cyst accumulation’ as a general proxy for oligotrophy or stratification in future palaeoenvironmental analyses. The acquired ‘reference’ data set of this study is large and diverse enough to allow its future application in quantitative palaeoenvironmental reconstruction models, and shows that there is still an enormous reconstruction potential concealed in many fossil calcareous dinoflagellate cyst assemblages.

Die Cypriniden (Teleostei: Cypriniformes) des oberoligozänen Maares von Enspel nebst Bemerkungen zur Phylogenie und Biogeographie der Phoxininae

Palaeorutilus enspelensis (Bohme 1996), the only fish species from the Upper Oligocene maar lake Enspel (Westerwald), is described and its phylogenetical position within the subfamily Phoxininae is discussed. The cladistic analysis of osteological and lepidological features indicates that the genusPalaeorutilusGaudant 1988 is a member of the Chub Clade. Furthermore, including of the recent Eurasian taxaLagowskiella andEupallasella in the analysis, the Chub Clade can be divided into two monophyletic Clades: the EurasianPhoxinus Clade (including the holarcticPhoxinus) and the eastern North American Creek Chub Clade which includes the fossil genusPalaeorutilus as its basal sister taxon. These phylogenetical investigation as well as the recent and fossil distribution pattern of the Phoxininae support the following biogeographical hypothesis: The settlement of cyprinids in North America took place in several waves and different directions. The separation of Western Clade and Chub Clade did not occur in North America but in Eocene times in Asia. Members of the Creek Chub Clade migrated from Europe to eastern North America via a transatlantic route prior to the Middle Miocene.