The changing role of terrestrial and autochthonous organic matter in newly flooded lakes

Examination of the gut contents of mud-dwelling animals in three newly flooded lakes shows terrestrial organic matter to be a major component, particularly during filling of the lake basin. After filling is complete, a fall-off in total biomass of fauna is usually accompanied by significant reduction in the proportion of terrestrial detritus in favour of algal food. It is concluded that newly formed lakes pass through two phases. During flooding they are dependent on the terrestrial ecosystem. This is followed by a switch, immediately after filling, to more self-sustained autochthonous-based food chains.     

Adequacy of terrestrial fauna surveys for the preparation of Environmental Impact Assessments in the mining industry of Western Australia

Summary   The Western Australian Environmental Protection Authority has indicated that terrestrial fauna surveys undertaken for the purpose of preparing Environmental Impact Assessment (EIA) are providing inadequate information for decision-makers to assess development impacts on biodiversity and ecosystems. This study examined the current standard of terrestrial vertebrate fauna surveys undertaken as the basis for preparing an EIA. In the absence of a protocol to assess current standards of terrestrial fauna surveys, 'best practice' was defined and quantified through consultation with an 'expert panel'. Data from fauna surveys contained in 15 recent EIA reports from the Goldfields region of Western Australia were critically examined to determine the extent of compliance with 'best practice'. The majority of surveys performed poorly against the established criteria. A few reports addressed many of the issues comprehensively, however, at least 50% failed to mention or adequately address a high proportion of criteria considered essential, including searches of government databases, detection of rare/endangered fauna and multiseasonal sampling. All reports failed to employ sufficient trapping effort at both the biotope and landscape scales to adequately assess terrestrial vertebrate fauna biodiversity. These results indicate the need to redress minimum standards for terrestrial fauna surveys in order to meet the expectations of the EIA process.     

Paleoecological and isotopic analysis of fossil continental mollusks of Sandelzhausen (Miocene,Germany)

The fossil molluscan fauna of Sandelzhausen (Early/Middle Miocene, SE Germany) comprises a total of 44 species, mostly terrestrial pulmonate snails. Herein we present a paleoecological analysis of this fauna based on an actualistic approach and on data on stable isotopes of carbon and oxygen (assessed from specimens of the freshwater lymnaeid snail Galba dupuyiana and the terrestrial clausiliid snail Pseudidyla moersingensis). The paleoecological reconstruction achieved here is in line with previous works, with some novelties and minor modifications. The basal sediment layers point to a swampy area with ponds and/or oxbow lakes (closed system, as indicated by the covariation between oxygen and carbon isotopic signals of G. dupuyiana), prone to seasonal flooding events. This environment would then gradually transition into a perennial lake, as indicated by: the proportion of planorbids, the appearance of aquatic species intolerant to desiccation, and the decoupling of the covariation between oxygen and carbon isotopic signals of G. dupuyiana. The terrestrial habitat would have developed from a more open environment (semi-arid/sub-humid scrubland) to a sub-humid/humid denser forest afterwards. Still, species from drier and more open environments are present throughout all the layers, suggesting that these habitats persisted in the lake’s hinterland. The mean annual temperature, calculated from the oxygen isotopic composition of P. moersingensis, ranges from 18.5 to 20.5 °C, but with no significant trend of change throughout the layers.     

Gastropod palaeohabitats of Miocene Lake Randeck Maar and its hinterland defined by an actualistic genus-level approach

The Randeck Maar lake sediments from SW Germany were deposited during a climatic phase known as the Mid-Miocene Climatic Optimum, providing a unique window into this last favourable period for a more thermophilous fauna in Central Europe. Previous palaeoecological reconstructions of Randeck Maar's environment focused on the flora and vertebrate fauna. Here, we present a palaeoecological analysis using gastropods as proxies by means of an actualistic genus-level approach. This approach is grounded in comparisons of habitat preferences between extant and fossil congeners and thus obviously requires a sound taxonomic framework. Despite being commonly applied in the literature, this approach has hardly been defined so far. Therefore, we thoroughly delineate it, exploring its applicability, potential and shortcomings. The molluscan fauna of Randeck Maar counts with 32 species of continental snails, mostly terrestrial pulmonates, related to the following palaeohabitats: littoral, supralittoral, rocky walls, shrubland, forests and open habitats. The gastropods indicate a warm-temperate climate with a dry season, in line with previous works on Randeck Maar's flora and vertebrates.     

A diverse fossil terrestrial arthropod fauna from New Zealand: evidence from the early Miocene Foulden Maar fossil lagerstätte

Fossil evidence for the evolutionary history of terrestrial arthropods in New Zealand is extremely limited; only six pre‐Quaternary insects (Triassic to Eocene) have been recorded previously, none of Miocene age. The Foulden Maar fossil lagerstätte in Otago has now yielded a diverse arthropod assemblage, including members of the Araneae, Plecoptera, Isoptera, Hemiptera, Coleoptera, Hymenoptera, Trichoptera and Diptera. The fauna significantly emends the fossil record for the Southern Hemisphere, provides an unparalleled insight into a 23‐million‐year‐old New Zealand lake/forest palaeoecosystem and allows a first evaluation of arthropod diversity at a time coeval with or shortly after the maximum marine transgression of Zealandia in the late Oligocene. The well‐preserved arthropods chiefly represent ground‐dwelling taxa of forest floor and leaf litter habitats, mostly from sub‐families and genera that are still present in the modern fauna. They provide precisely dated fossil evidence for the antiquity of some of New Zealand's terrestrial arthropods and the first potential time calibrations for phylogenetic studies. The high arthropod diversity at Foulden Maar, together with a subtropical rainforest flora and fossil evidence for complex arthropod–plant interactions, suggests that terrestrial arthropods persisted during the Oligocene marine transgression of Zealandia.     

Littoral benthos of a Victorian lake and its outlet stream: Spatial and temporal variation

Abstract There have been few comparative studies of the fauna in the two major types of freshwater systems, lakes and streams, in the one locality. This study compared the faunal assemblages at two times of the year (summer and winter) on stones in three locations: the littoral zone of two shores in Lake Purrumbete (one wave-exposed and one sheltered) and riffles in the Curdies River, which flows out of the lake. The lake fauna was dominated by crustaceans, gastropods and planarians, whereas the stream fauna was dominated by insects. The most abundant lake taxa were also present, but much less abundant, in the stream. The total number of species and individuals and densities of some common species varied between the three locations and between seasons. However, no consistent pattern reflecting a difference between the two lake shores was evident. Interpretation of MDS ordinations of the lake fauna was dependent on the data standardizations applied, with increased separation of the season-location combinations when species were standardized to equal total abundances; the seasonal difference was always greatest for the exposed (cliff) shore. In contrast, MDS on the stream fauna showed seasonal differences under all standardizations. This was consistent with the high seasonal turnover of species in the stream compared with the lake. These results demonstrate that, even within a local area with similar geology and connected water bodies, lake and stream fauna from the same substratum (stones) can be markedly different. Taxa that occurred in both were more abundant in the lake, whereas seasonal differences in abundance were much greater in the stream.     

Mega-island or micro-continent? New Zealand and its fauna

The terrestrial New Zealand fauna has developed on an ancient landmass of continental origins that has had an increasingly isolated existence since the late Mesozoic. As a continental remnant, New Zealand harbours survivors of many ancient lineages many of which were once far more widely distributed. But New Zealand's fauna also resembles that of an isolated archipelago: many higher taxa are missing; some have undergone extensive radiations in situ; and levels of endemism approach 100% in many groups. Ecologically, the fauna is characterized by frequent niche shifts, gigantism, and extended life histories with low reproductive rates, factors that make many species vulnerable to human disturbance. Data continue to amass supporting the ecophysiological as well as phylogenetic distinctiveness of the fauna. Described taxonomic diversity, even of terrestrial vertebrates, continues to increase.     

Responses of insects,especially Chironomidae (Diptera), and mites to 130 years of acidification in a Scottish lake

About 130 years of anthropogenic acidification of Round Loch of Glenhead, SW Scotland, has resulted in successively decreased stability, diversity, productivity and survival rate of the non-biting midge (Diptera: Chironomidae) fauna. Similar trends have also been observed among mayflies, caddis-flies and water mites. The first effects of anthropogenic acidification on the insect and mite fauna, as evidenced by palaeolimnological analyses of²¹⁰Pb-dated sediment cores, occurred as early as around 1850, i.e. earlier than in any other lake hitherto studied. The drop in the lake's pH was first indicated by decreased stability and changes in species composition of chironomids and mayflies in the littoral zone. Major changes in the profundal chironomid fauna did not take place until about 1950, when mean lake pH dropped below 5.0. At the same time, the littoral insect fauna became even more unstable and the first significant elimination of species occurred. Comparison with insect fauna of other lakes suggests that a pH of less than 5 might be critical for the ecological conditions in many acidified lakes. None of the twelve most common chironomid species present prior to the acidification of the lake had disappeared after 120–130 years of considerable acidification, and they are all common in oligotrophic lakes with a pH of 6.5–7.0. This is in contrast to the effects of heavy acidification on other aquatic animal groups. Chironomids are probably more sensitive to lake trophic status than lake acidity.     

Links between Terrestrial Primary Production and Bacterial Production and Respiration in Lakes in a Climate Gradient in Subarctic Sweden

We compared terrestrial net primary production (NPP) and terrestrial export of dissolved organic carbon (DOC) with lake water heterotrophic bacterial activity in 12 headwater lake catchments along an altitude gradient in subarctic Sweden. Modelled NPP declined strongly with altitude and annual air temperature decreases along the altitude gradient (6°C between the warmest and the coldest catchment). Estimated terrestrial DOC export to the lakes was closely correlated to NPP. Heterotrophic bacterial production (BP) and respiration (BR) were mainly based on terrestrial organic carbon and strongly correlated with the terrestrial DOC export. Excess respiration over PP of the pelagic system was similar to net emission of CO₂ in the lakes. BR and CO₂ emission made up considerably higher shares of the terrestrial DOC input in warm lakes than in cold lakes, implying that respiration and the degree of net heterotrophy in the lakes were dependant not only on terrestrial export of DOC, but also on characteristics in the lakes which changed along the gradient and affected the bacterial metabolization of allochthonous DOC. The study showed close links between terrestrial primary production, terrestrial DOC export and bacterial activity in lakes and how these relationships were dependant on air temperature. Increases in air temperature in high latitude unproductive systems might have considerable consequences for lake water productivity and release of CO₂ to the atmosphere, which are ultimately determined by terrestrial primary production.     

Survey of the terrestrial and freshwater molluscan fauna of the Pilliga forest area in northern inland New South Wales,Australia

The Pilliga forest in northern inland New South Wales, Australia, is one of the largest surviving remnants of native forest on the western slopes of the Great Dividing Range. The Pilliga landscape is a challenging environment for molluscs, dominated by dry sclerophyll forest and with limited and largely ephemeral aquatic habitats. A field survey of the area in 2006–2012 identified a surprisingly rich and relatively intact aquatic native molluscan fauna with five species of bivalves in three families and nine species of freshwater gastropods (four families), including some rare species and range extensions. The native land snail fauna comprised 18 species (six families), including an unusually rich pupillid fauna with nine species. Some range extensions are recorded and some species are narrow-range endemics. The distributions of many aquatic and terrestrial species were correlated with geology or soil type. Introduced molluscs were predominantly found in anthropogenic habitats and include two freshwater gastropods (two families) and nine terrestrial snails and slugs (eight families). This study provides insight into the original molluscan fauna of the western slopes prior to landscape-scale agricultural development and provides a benchmark for future reference.     

Temperature and Moisture Modulate the Contribution of Soil Fauna to Litter Decomposition via Different Pathways

Ecosystems - Soil fauna are crucial decomposers in terrestrial ecosystems, but how the role of soil fauna varies among climatic conditions and litter substrates remains poorly understood. Here, we...     

Rudabànya: Taphonomic analysis of a fossil hominid site from Hungary

The late Miocene deposits at Rudabànya, Hungary, were laid down in a shallow valley sloping westwards from a range of hills and opening out into the Pannonian Lake. Rise and fall of lake level gave rise to varying conditions, from dry land with soil formation to swamp and lake. The stratigraphic and palaeontological succession has been investigated at one of the sites, Rudabànya 2, where two cycles of deposition and erosion are represented, with soil formation, swamp conditions with lignite formation, and periods of extended high lake level succeeding each other. Both mammal and plant fossils are present at several levels. Taphonomic modifications in the Rudabànya 2 vertebrate faunas include losses of skeletal elements through carnivore selection, fluvial sorting at some levels, and post-depositional destruction by leaching and/or acid soils. The lowest level, the lower lignite, has few fossils. The fossil mammals from the level above, the grey marl, are the least modified but they are mixed with abraded, probably allochthonous, bone fragments and more complete specimens resulting from near-lake deaths. Modifications of bones by carnivores are indicated, but the specimens were too broken post-depositionally for the impact of the carnivores to be assessed. Carnivore action is also indicated for the fauna of the black clay which formed on the surface of the grey marl. The fauna consists of relatively abundant small mammals and the primates Anapithecus hernyaki and Dryopithecus hungaricus, with the latter much less common. The predator accumulating the smaller species was probably a viverrid. The red marl fauna is a transported assemblage from higher up the valley with the fossils extremely fragmentary and abraded and few identifiable specimens, almost all of which are teeth. The black mud fauna is also probably a transported assemblage, lower energy than the red marl environment, and the bones are much modified subsequently by acid corrosion similar to that seen today in bone preserved in peat bogs. Dryopithecus is a major constituent of the fauna, with Anapithecus less common. D. hungaricus is thus associated more strongly with swamp forest and shallow riverine conditions with low energy movement of water, and A. hernyaki is associated with lake shore (probably forest) conditions, accumulating in lake sediments and lake-flat sediments. The palaeoecology of the area as a whole, based on the associated flora and fauna, is a combination of swamp forest, lake shore forest and open mud flats.     

高原湖泊湿地以植被指示为主的环评指标初探

分析探讨高原湖泊湿地的环境评价中,如何应用一套由植被为主指示要素构成的环评指标,并以云南石林长湖湖泊湿地为实例。按植被及其植物区系组成、动物区系和生境方面所表现特征的现况,共设置以植被特征为主的10个评定指示要素。使用此类指标评价的前提是:所评的各个高原湖泊湿地,均在上述10个所规定的指示要素方面,已取得调查研究的定量和定性数据资料。所以本方案的使用,反而促成各高原湖泊湿地在以植被特征为主各评价要素的进一步考察和研究,以作为参评的依据。     

The Postglacial History of Lake Flarken,Southern Sweden,Interpreted from Subfossil Insect Remains

A correlation of changes in the composition of chironomid and chaoborid remains and changes in sediment chemical composition, floristic, and other faunistic information indicate that a decreasing productivity and an increasing humic level characterized the development of the small Lake Flarken, Southern Sweden, during the postglacial period. Pronounced changes in the fauna were correlated with fluctuations of the water level in the lake, which was caused by changes in the humidity of the climate. Significant human influence on the lake has only occurred in recent years, during which a rapid acidification has caused the most dramatic change in the fauna, by far, in the whole history of the lake.     

Distribution of macroinvertebrates in the shallow part of ‘De Gijster’, a water storage lake in the Biesbosch (The Netherlands)

The composition and distribution of the macroinvertebrate fauna of the shallow part of De Gijster, a medium sized water storage lake in The Netherlands, has been studied during 1984. The numerous individuals collected belong mainly to the Oligochaeta, Diptera (Chironomidae larvae) and Mollusca. Amongst them are elements of both the former polder fauna and the river fauna. A quantitative analysis revealed data on the horizontal distribution of several taxa within the lake as well as data on the influence of the lifecycle of some taxa on the annual composition of the fauna.     

Zoning Northern Eurasia based on the fauna of terrestrial vertebrates and their classification by similarity of distribution

For the purpose of zoning on the basis of fauna of terrestrial vertebrates, Northern Eurasia was considered within the boundaries of the Soviet Union in 1991 and divided into 245 mapping units. Mapping units were marked on the World Vegetation Map at a scale of 1: 20000000 in such a way that each mapping unit occupied a territory within the limits of a natural subzone having a latitudinal distance of 10°. A list of the vertebrate species was generated for each unit. Jaccard similarity coefficients were calculated for the lists; the coefficients were used as the basis for performing the cluster analysis of fauna of the mapping units. Based on the results of calculations, a hierarchical classification has been created. This classification includes 5 faunistic regions (regional groups of subregions), 6 subregions, 18 provinces, and 14 districts. Environmental factors that correlate with faunistic heterogeneity in the studied territory were described. The proposed zoning takes into account 57% of the variance of the similarity coefficients of the faunas of specific regions (coefficient of multiple correlation is 0.75). It is 2–2.5 times more informative than the previously developed schemes on particular groups of animals, which reflected, as the researchers thought at that moment, the heterogeneity of fauna of terrestrial vertebrates in general. Association with environmental factors and natural conditions may explain 82% of the heterogeneity of the fauna (correlation coefficient is 0.91). Comparing the results of zoning that were carried out for different classes of terrestrial vertebrates (amphibians, reptilians, birds, and mammals), we found significant similarity between causes of fauna heterogeneity (zonal features, provinciality, heat availability, and their combined effect). Nevertheless, differences in tolerance to the environment among the studied animal classes resulted in the substantial discordance of the boundaries of the described taxa and their hierarchy. This discordance was found during zoning. A classification of 1243 species of terrestrial vertebrates inhabiting the territory under study is performed based on the similarity of their occurrence (the average in the lower taxon faunistic zoning) and covers three types of distribution: Northern, Middle and Southern. These in turn are divided into 7 subtypes and 13 classes. The informative presentation of the classification is equal to 53% of the variance (correlation coefficient is 0.73).     

The effects ofTilapia introductions in Lake Luhondo,Rwanda

Synopsis Cyprinid fishes apparently constituted the major part of the original fish fauna in Lake Luhondo, Rwanda, at least until 1934. At that time only three species, all cyprinids, were known from the lake:Barbus neumayeri, a small barbel, very common in the lake (described from the lake asBarbus luhondo) and two larger cyprinid species:Barbus microbarbis andVaricorhinus ruandae. These two large species were probably not very common in the lake. Between 1935 and 1938 some youngTilapia were introduced into Lake Luhondo. Since then and certainly since 1952 the large cyprinids seem to have disappeared completely from the lake. The smallBarbus neumayeri has become extremely rare; at present it survives only in some small tributaries of the lake. In the lake itselfTilapia andHaplochromis species are now the dominant fauna. A survey of the available information is given.Africa-Museum, Steenweg op Leuven, B-1980 Tervuren, Belgium (mailing address)     

Habitat structure determines resource use by zooplankton in temperate lakes

While the importance of terrestrial linkages to aquatic ecosystems is well appreciated, the degree of terrestrial support of aquatic consumers remains debated. Estimates of terrestrial contributions to lake zooplankton have omitted a key food source, phytoplankton produced below the mixed layer. We used carbon and nitrogen stable isotope data from 25 Pacific Northwest lakes to assess the relative importance of particulate organic matter (POM) from the mixed layer, below the mixed layer and terrestrial detritus to zooplankton. Zooplankton and deep POM were depleted in 13C relative to mixed layer POM in lakes that can support deep primary production. A Bayesian stable isotope mixing model estimated that terrestrial detritus contributed <5% to zooplankton production, and confirms the role of lake optical and thermal properties; deep POM accounted for up to 80% of zooplankton production in the clearest lakes. These results suggest terrestrial support of lake zooplankton production is trivial.