Resting eggs of Anostraca,Notostraca and Spinicaudata (Crustacea,Branchiopoda) occurring in France: identification and taxonomical value

The external egg morphology of the phyllopod species recorded in France is described by means of S.E.M. Differences in diameter and ornamentation of envelope are stressed. We propose a dichotomous key to allow the identification of species even when their biotope is dry. Results are compared with previous studies on Anostraca, Notostraca and Spinicaudata and their taxonomical value is discussed.     

Assemblage structure and dynamics of large branchiopods in Mediterranean temporary wetlands: patterns and processes

1. To monitor the diversity and distribution patterns of large branchiopods and the effects of local and regional processes, 30 temporary wetlands in a nature reserve in the Camargue (southern France) were sampled and characterised during three consecutive inundations (2005–08). Additional species were added to the list for each wetland by hatching animals from the resting egg bank, after determining the optimal hatching conditions.
2. A total of five species were found, representing 28% of the species known in France and 56% of the known Camargue species. Tanymastix stagnalis , Branchipus schaefferi , Chirocephalus diaphanus (Anostraca), Triops cancriformis (Notostraca) and Imnadia yeyetta (Spinicaudata) were distributed over a total of 19 wetlands.
3. More than one species was present in 79% of the wetlands containing large branchiopods. Individual wetlands harboured on average 2.8 species, with a maximum of five coexisting species. Large branchiopod assemblages were temporally variable, differing among the three inundations with different climatological conditions.
4. The most important habitat factor influencing the distribution of large branchiopods was salinity, adversely affecting the density and survival of hatchlings. The persistence of large branchiopods in these temporary waters may be threatened by increasing salinisation driven by intensive water management and climate change.     

Anostraca,Notostraca, Laevicaudata and Spinicaudata of Pannonian region and in its Austrian area

The northwestern area of the Pannonian Lowland extends into Austria. The climatic and hydrologic attributes of this biographic region promote the existence of extremely astatic bodies water lacking any fish and hence the occurrence of Anostraca, Notostraca, Laevicaudata and Spinicaudata. Zoogeographical and ecological features as well as the extinction of species due to anthropogenic influence are described.Dedicated to Prof. Dr F. Berger, Lunz, Austria, on the occasion of his 90th birthdayDedicated to Prof. Dr F. Berger, Lunz, Austria, on the occasion of his 90th birthday     

Phylogeny of Branchiopoda (Crustacea) based on a combined analysis of morphological data and six molecular loci

The phylogenetic relationships of branchiopod crustaceans have been in the focus of a number of recent morphological and molecular systematic studies. Although agreeing in some respects, major differences remain. We analyzed molecular sequences and morphological characters for 43 branchiopods and two outgroups. The branchiopod terminals comprise all eight “orders”. The molecular data include six loci: two nuclear ribosomal genes (18S rRNA, 28S rRNA), two mitochondrial ribosomal genes (12S rRNA, 16S rRNA), one nuclear protein coding gene (elongation factor 1α), and one mitochondrial protein coding gene (cytochrome c oxidase subunit I). A total of 65 morphological characters were analyzed dealing with different aspects of branchiopod morphology, including internal anatomy and larval characters. The morphological analysis resulted in a monophyletic Phyllopoda, with Notostraca as the sister group to the remaining taxa supporting the Diplostraca concept (“Conchostraca” + Cladocera). “Conchostraca” is not supported but Cyclestheria hislopi is the sister group to Cladocera (constituting together Cladoceromorpha) and Spinicaudata is closer to Cladoceromorpha than to Laevicaudata. Cladocera is supported as monophyletic. The combined analysis under equal weighting gave results in some respects similar to the morphological analysis. Within Phyllopoda, Cladocera, Cladoceromorpha and Spinicaudata + Cladoceromorpha are monophyletic. The combined analysis is different from the morphological analysis with respect to the position of Notostraca and Laevicaudata. Here, Laevicaudata is the sister group to the remaining Phyllopoda and Notostraca is sister group to Spinicaudata and Cladoceromorpha. A sensitivity analysis using 20 different parameter sets (different insertion–deletion [indel]/substitution and transversion/transition ratios) show the monophyly of Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cladoceromorpha, Cladocera, and within Cladocera, of Onychopoda and Gymnomera under all or almost all (i.e., 19 of 20) parameter sets. Analyses with an indel‐to‐transversion ratio up to 2 result in monophyletic Phyllopoda, with Laevicaudata as sister group to the remaining Phyllopoda and with Spinicaudata and Cladoceromorpha as sister groups. Almost all analyses (including those with higher indel weights) result in the same topology when only ingroup taxa are considered. © The Willi Hennig Society 2007.     

Large branchiopod Crustacea (Anostraca,Notostraca, Spinicaudata) of the Barents Region of Russia

The Russian Territory known as the Barents Region includes the large islands of Vaigatch and Kolguev, the archipelagos of Franz Joseph Land and Novaya Zemlya, and many small near shore islands in the Barents Sea subregion of the Arctic Ocean. With the exception of Franz Joseph Land, these islands and the Novaya Zemlya Archipelago are inhabited by seven species of large branchiopods: four species of Anostraca, Polyartemia forcipata S. Fischer, 1851, Artemiopsis bungei plovmornini Jaschnov, 1925, Branchinecta paludosaMüller, 1851 and Branchinectella media (Schmankewitsch, 1873); one Notostraca, Lepidurusarcticus (Kroyer, 1847); and two species of Spinicaudata, Caenestheria propinqua Sars, 1901and C. sahlbergi (Simon, 1886). This is a richer large branchiopod fauna than occurs in other comparable land areas of the Arctic Ocean. The northern most known occurrence of Branchinecta paludosa is at Ivanov Bay on the Novaya Zemlya Archipelago. This report includes some life history observations. This revised version was published online in August 2006 with corrections to the Cover Date.     

California vernal pool endemic responses to hydroperiod,plant thatch,and nutrients

Many endemic large branchiopods inhabit ephemeral freshwater ecosystems, including California vernal pools. Hydroperiod, inundation length, has been well studied in these systems that cycle between aquatic and terrestrial phases, but species’ responses to other ecological processes are still poorly known. For example, temporal (plant thatch from the previous terrestrial phase) and spatial (nutrient runoff) factors may have strong effects on emergence and population densities during the aquatic phase. We examined the effects of hydroperiod stability, thatch, and nutrients on the emergence and density of 4 vernal pool endemic species: Branchinecta lynchi (Anostraca), Linderiella occidentalis (Anostraca), Lepidurus packardi (Notostraca), and Cyzicus californicus (Spinicaudata). A full factorial mesocosm experiment was conducted which measured species densities, along with water quality variables. Hydroperiod and thatch differentially affected 3 of the 4 species based on emergence timing and life cycle. Treatments had effects on many water quality variables, and these variables were correlated with densities. These results highlight how hydroperiod stability along with other processes can affect large branchiopod species in temporary freshwater ecosystems. California vernal pools are a greatly reduced habitat rich in endemic and endangered species (including Branchinecta lynchi and Lepidurus packardi), and therefore, these results have implications for conservation and management.     

Plant community patterns in Moroccan temporary ponds along latitudinal and anthropogenic disturbance gradients

Background: Temporary ponds, an abundant habitat in the Maghreb region and notably in Morocco, have a high conservation value. However, they are mainly known from the north of the country.

Aims: The aim of this work was to characterise the vegetation of Moroccan temporary ponds along a combined gradient of latitude and anthropogenic pressure.

Methods: Eighty-five ponds distributed along a north–south gradient of 750 km were sampled. For each pond, all vegetation was surveyed (flooded and dry parts) and the local abiotic characteristics were measured during two successive hydrological cycles. The prevailing anthropogenic pressures were also identified and were attributed an impact score.

Results: Eighty-one characteristic pond species (including 17 rare species) were recorded, with several new distribution data in the southern part of the latitudinal gradient. Plant communities were related to climatic and anthropogenic factors, but mostly to local factors, such as maximum water depth and soil pH. The northern ponds (wettest macroclimate) were rich in characteristic species and rare species, while the southern (driest macroclimate) ponds were more species poor.

Conclusions: In addition to the direct impact of increasing human activity, a further reduction of the floristic richness of temporary ponds is expected due to climatic changes. This is particularly the case for characteristic species which have a high conservation value.     

New records of large branchiopods (Branchiopoda: Anostraca,Notostraca, and Spinicaudata) in Mexico

This paper reports new distribution records of large branchiopods for Mexico following a three year survey of the Baja California peninsula. The occurance of the anostracans Thamnocephalus mexicanus (Linder, 1941) and T. platyurus (Packard, 1877), the notostracan Lepidurus lemmoni (Holmes, 1894), and the spinicaudatans Eulimnadia cylindrova (Belk, 1989) and E. texana (Packard,1871), all represent the first records for the peninsula. An undescribed species of the anostracan genus Streptocephalus is recorded from the state of Baja California (Norte). The occurrence of the notostracan genus Triops and four other anostracan species on the peninsula is also confirmed. The conchostracan Cyclestheria hislopi (Baird, 1859) is recorded from the state of Quintana Roo. The collections of Lepidurus and Cyclestheria are the first records for México. These records increase the number of species of large branchiopods reported fromMéxico to 36: 20 Anostraca, 3 Notostraca, 11 Spinicaudata, and 2Laevicaudata. This revised version was published online in August 2006 with corrections to the Cover Date.     

The distribution of pond snail communities across a landscape: separating out the influence of spatial position from local habitat quality for ponds in south-east Northumberland,UK

Ponds support a rich biodiversity because the heterogeneity of individual ponds creates, at the landscape scale, a diversity of habitats for wildlife. The distribution of pond animals and plants will be influenced by both the local conditions within a pond and the spatial distribution of ponds across the landscape. Separating out the local from the spatial is difficult because the two are often linked. Pond snails are likely to be affected by both local conditions, e.g. water hardness, and spatial patterns, e.g. distance between ponds, but studies of snail communities struggle distinguishing between the two. In this study, communities of snails were recorded from 52 ponds in a biogeographically coherent landscape in north-east England. The distribution of snail communities was compared to local environments characterised by the macrophyte communities within each pond and to the spatial pattern of ponds throughout the landscape. Mantel tests were used to partial out the local versus the landscape respective influences. Snail communities became more similar in ponds that were closer together and in ponds with similar macrophyte communities as both the local and the landscape scale were important for this group of animals. Data were collected from several types of ponds, including those created on nature reserves specifically for wildlife, old field ponds (at least 150 years old) primarily created for watering livestock and subsidence ponds outside protected areas or amongst coastal dunes. No one pond type supported all the species. Larger, deeper ponds on nature reserves had the highest numbers of species within individual ponds but shallow, temporary sites on farm land supported a distinct temporary water fauna. The conservation of pond snails in this region requires a diversity of pond types rather than one idealised type and ponds scattered throughout the area at a variety of sites, not just concentrated on nature reserves. Handling editor: B. Oertli     

A field study of larval development in a dragonfly assemblage in African desert ponds (Odonata)

Aquatic animals distributed along a 'habitat-permanence' gradient (HPG), differ in life history (Wellborn et al., 1996. Annual Revue of Ecology and Systematics 27: 337--363). Dragonflies that occur in hot arid regions often occur in temporary waters and consequently perform direct and rapid development. Dragonfly species of the Namibian desert do differ in their selection of habitats along the HPG and therefore may also differ in life cycle. Here, we attempt to monitor colonisation, larval growth and emergence in a temporary pond of known history. We studied the development of dragonfly species that laid eggs in artificial ponds constructed by us in March 2001. The assemblage consisted of species that originate from different habitats along the HPG. To obtain data on larval development we took samples from the ponds at 10-day intervals. Most species showed rapid development. By regressing the maximum sizes attained by larvae on each sampling date against time we estimated growth rates for five species and were thereby able to estimate that total duration of development from oviposition to emergence ranged between 38 and 70 days. Observation of first oviposition and first emergence for three of these species corroborated our estimates based on growth rate. Of few species, which laid eggs in the ponds no larvae or adults were found. For some this may have been the result of predation whereas others may not have grown fast enough to emerge before the ponds dried up. Our results indicate that dragonflies cannot recognise whether a pond will retain water long enough for full larval development and oviposit in waters that will not allow larval development.     

Fission and the dynamics of genets and ramets in clonal cnidarian populations

Until relatively recently many species of entomostracan crustaceans were thought to have widespread, even cosmopolitan distributions. Evidence now suggests that this is far less the case than thought. However, an exception appears to be provided by the crustaceans of episodically filled waterbodies. Typically these include Anostraca, Notostraca and Conchostraca. The paper considers the distribution of Triops australiensis (Branchiopoda: Notostraca) in Australia. There, it is a frequent inhabitant of episodically filled temporary waters. It is absent from such waters in northern Australia. A biogeoclimatic analysis using the program BIOCLIM indicates that this is because of the absence of suitable localities. BIOCLIM enables the preparation of maps which provide statistical predictions of climates suitable for the survival of a particular taxon. These predictions are based upon the known climate of localities where the taxon in question actually occurs. It is suggested that for the biota of shallow ephemeral waters (such as those typically inhabited by Anostraca, Conchostraca and Notostraca) biogeoclimatic analysis has a powerful predictive value.     

Spatiotemporal allozyme variation in the damselfly, <Emphasis Type="BoldItalic">Lestes viridis</Emphasis> (Odonata: Zygoptera): gene flow among permanent and temporary ponds

Several insect species seem to persist not only in permanent but also in temporary ponds where they face particularly harsh conditions and frequent extinctions. Under such conditions, gene flow may prevent local adaptation to temporary ponds and may promote phenotypic plasticity, or maintain apparent population persistence. The few empirical studies on insects suggest the latter mechanism, but no studies so far quantified gene flow including both pond types. We investigated the effects of pond type and temporal variation on population genetic differentiation and gene flow in the damselfly Lestes viridis in northern Belgium. We report a survey of two allozyme loci (Gpi, Pgm) with polyacrylamide gel electrophoresis in 14 populations from permanent and temporary ponds, and compared these results with similar data from the same permanent populations one year before. The data suggested that neither pond-drying regime, nor temporal variation have a substantial effect on population genetic structuring and did not provide evidence for stable population differentiation in L. viridis in northern Belgium. Gene flow estimates were high within permanent and temporary ponds, and between pond types. Our data are consistent with a source-sink metapopulation system where temporary ponds act as sinks in dry years, and are quickly recolonized after local population extinction. This may create a pattern of apparent population persistence of this species in permanent and temporary ponds without clear local adaptation.     

Biotic and abiotic parameters that distinguish types of temporary ponds in a Portuguese Mediterranean ecosystem

Temporary ponds are seasonal wetland habitats subjected to extreme and unstable ecological conditions. Some are classified as priority habitats for conservation by the European Union Habitats Directive. Our study area was the coastal plain of southwest Portugal, which spans across 100 km north to south and hosts a large number of temporary ponds as a consequence of climatic and edaphic characteristics. Field sampling of floristic and edaphic data was carried out in 24 temporary ponds every spring between 2005 and 2008. We recorded a total of 174 plant species identified within visually homogeneous plots. We included the data in a geographic information system and classified ponds according to their floristic composition, using a biotic regionalization analysis based on species presence/absence, which is a practical and unambiguous criterion. We found three significantly different groups of ponds which corresponded to an eco-physiognomic pond typology: Mediterranean temporary ponds, marshlands, and disturbed ponds. For the first two pond types we defined characteristic or indicator plant species. We searched also for relationships between pond type and a series of large-scale climatic, geographic, and geological variables, as well as local-scale physical and chemical properties of the soil. Pond type was distinguished by a complex combination of some of these variables, including environmental energy, soil texture, nitrogen content of the soil and pH. A practical way of discriminating between different types of ponds is important so that management and conservation measures can be defined accordingly.     

Spatiotemporal allozyme variation in the damselfly, Lestes viridis (Odonata: Zygoptera): gene flow among permanent and temporary ponds

Several insect species seem to persist not only in permanent but also in temporary ponds where they face particularly harsh conditions and frequent extinctions. Under such conditions, gene flow may prevent local adaptation to temporary ponds and may promote phenotypic plasticity, or maintain apparent population persistence. The few empirical studies on insects suggest the latter mechanism, but no studies so far quantified gene flow including both pond types. We investigated the effects of pond type and temporal variation on population genetic differentiation and gene flow in the damselfly Lestes viridis in northern Belgium. We report a survey of two allozyme loci (Gpi, Pgm) with polyacrylamide gel electrophoresis in 14 populations from permanent and temporary ponds, and compared these results with similar data from the same permanent populations one year before. The data suggested that neither pond-drying regime, nor temporal variation have a substantial effect on population genetic structuring and did not provide evidence for stable population differentiation in L. viridis in northern Belgium. Gene flow estimates were high within permanent and temporary ponds, and between pond types. Our data are consistent with a source-sink metapopulation system where temporary ponds act as sinks in dry years, and are quickly recolonized after local population extinction. This may create a pattern of apparent population persistence of this species in permanent and temporary ponds without clear local adaptation.     

Community structure of branchiopods (Anostraca,Notostraca and Conchostraca) in the Banat province in Yugoslavia

A survey of large branchiopods in the Banat provincein Yugoslavia revealed a particularly diverse fauna in the vicinity of the village Melenci, 100 km north of Belgrade. The temporary ponds here include 10 species of branchiopods, 5 anostracans, 2 notostracans and 3conchostracans (all belonging to the Spinicaudata group). This diversity represents 53% of the species known in Yugoslavia. Community structure, spatial distribution and seasonal dynamics of the species were analyzed over the period 1991–1995. More than one species was found in about 67% of ponds. The maximum number of coexisting species was 7.Anostracans were the most common as a group, while the notostracan Triops cancriformis and the conchostracan Leptestheria saetosa were the most frequent species. A high frequency of coexistence was established. Regarding community structure, two significantly different periods during the season were distinguished: the first, from the end of February to mid-April, and the second, from mid-April to the end of July. This extensive pool longevity may underlie the high diversity in this region. This revised version was published online in August 2006 with corrections to the Cover Date.     

Tadpole competition in a desert anuran community

Summary Five interspecific competition experiments performed in artificial ponds under temporary pond-like conditions established that temporary and permanent pond tadpoles interact. Temporary pond species typically lowered survivorship and reduced progress towards metamorphosis of permanent pond tadpoles. These results suggest that competitive interactions may partially determine the local distribution of tadpoles in the Chihuahuan Desert by preventing some permanent pond anurans from using temporary ponds. Predation by Scaphiopus multiplicatus tadpoles (a temporary pond species) may also prevent permanent pond tadpoles from using temporary ponds.     

Small area and low connectivity constrain the diversity of plant life strategies in temporary ponds

Aim

(i) To determine whether area and connectivity of temporary ponds can predict plant species diversity, and the diversity and abundance of different plant life histories; (ii) To explore whether pond connectivity with the river prior to river regulation predicts better plant diversity patterns than current pond connectivity, suggestive of possible effects of connectivity loss.

Location

Eastern Carpathian Mountains, Romania, Europe.

Methods

We fitted linear and generalized linear models (LM and GLM) to examine whether pond area and current distance from the Olt River predict plant species richness, Shannon diversity and relative cover of different social behaviour types and overall plant species richness and Shannon diversity. Using historical maps, we measured pond distance from the river ca. 60 years before the Olt River was regulated, and we refitted the LM and GLM models using pond area and past distance from the river as independent variables.

Results

Total plant species richness increased with pond area, and it decreased with the distance from the river, but total plant Shannon diversity index was affected, positively, only by pond area. The strength of responses to pond area and connectivity of species richness, Shannon diversity and relative cover varied across the different social behaviour types. Past and current distances between ponds and riverbeds had similar effects on plant diversity, with some evidence for stronger effect of the present connectivity on specialist species Shannon diversity and a weaker effect on disturbance tolerants, generalists and competitors.

Main Conclusions

Pond area and connectivity with the landscape are important predictors of the diversity of plant life history strategies, and therefore, useful tools in pond conservation. Consistent species richness and Shannon diversity responses of wetland specialists to pond area and connectivity make this life history type well suited for monitoring pond condition.     

Are cladoceran diversity and community structure linked to spatial heterogeneity in urban landscapes and pond environments?

Biodiversity patterns in cladoceran communities were investigated in urban waterbodies in relation with residential land use, pond management, and waterbody environments. We evaluated species richness in the pelagic and littoral zones of eighteen waterbodies of a large Canadian city. Gamma diversity (26 species) observed at a small scale in the urban survey was important comparatively to large-scale surveys of lakes. Beta diversity ranged from 1 to 8 species among waterbodies. We tested if littoral species greatly contributed to regional diversity in urban waterbodies. Littoral species (Chydoridae, Ilyocryptidae, Macrothricidae, Polyphemidae) accounted for 58% of the total species pool. We distinguished five cladoceran assemblages associated to different waterbodies (temporary ponds, permanent lakes, and wetlands). Cladoceran communities were more diverse and variable in permanent lakes than in temporary ponds. Changes in cladoceran species assemblages among waterbodies were driven by variations in waterbody size and phosphorus enrichment, macrophyte and algal biomass, urban density, pond management practices, and the presence of potential predators as fish and macroinvertebrates. Our study indicates that both artificial ponds and lakes and natural wetlands are valuable habitats for the conservation of cladoceran biodiversity and rare endemic species in urban regions. Further research on pond management strategies promoting urban aquatic biodiversity should be undertaken.     

Spatial and temporal variability of aquatic habitat use by amphibians in a hydrologically modified landscape

1. Habitat loss is a major driver of biodiversity decline worldwide. Temporary waterbodies are especially vulnerable because they are sensitive both to human impact and to climatic variations. Pond‐breeding amphibians are often dependent on temporary waterbodies for their reproduction, and hence are sensitive to loss of temporary ponds. 2. Here we present the results of a 5‐year study regarding the use of temporary aquatic habitats by amphibians in a hydrologically modified area of Eastern Europe (Romania). The annual number of aquatic habitats varied between 30 and ～120. Each aquatic habitat was characterised by a number of variables such as: ‘type’ (pond, drainage ditch and archaeological ditch), ‘hydroperiod’ (number of weeks the ponds were filled in a given year), ‘depth’ (cm), ‘area’ (m²) and the density of predatory insects (‘predation’). The turnover rate for each amphibian species for each wetland was calculated based on the pond occupancy. 3. Eight amphibian species were recorded from the aquatic habitats. Hydroperiod was the most important variable, positively influencing wetland use by amphibians and their reproductive success. Most species preferred drainage ditches for reproduction, and the reproductive success was highest in this habitat type every year. For most of the species, the local extinction rate was higher than the colonisation rate in the first 4 years, but the situation reversed in the last year of the study when wetland use by amphibians sharply increased because of high rainfall. 4. This study confirms the importance for amphibians of maintaining and managing aquatic habitat diversity at small spatial scales. Man‐made aquatic habitats such as drainage ditches may be important habitats for amphibians, and this should be considered in restoration activities.     

Simple pond restoration measures increase dragonfly (Insecta: Odonata) diversity

Ponds are home to a diverse community of specialized plants and animals and are hence of great conservation concern. Through land-use changes, ponds have been disappearing rapidly and remaining ponds are often threatened by contamination and eutrophication, with negative consequences for pond-dependent taxa like amphibians or dragonflies (Odonata: Anisoptera and Zygoptera). Increasingly, restoration measures such as removal of shading terrestrial vegetation or submerged organic matter are implemented to counteract current threats, but how these measures affect the target taxa is rarely assessed. We tested if and how simple pond restoration measures affectionate diversity. We propose that pond restoration influences the light regime, which promotes aquatic and riparian vegetation important for different dragonfly life stages, thus increasing their diversity. Additionally, we assume that this changes dragonfly species composition between restored and unrestored ponds. We surveyed exuviae in the riparian and aquatic vegetation along the shore of 29 (12 restored, 17 unrestored) man-made ponds in southwest Germany and assessed environmental variables known to affect dragonfly diversity. We identified the cover of tall sedges and submerged macrophytes as the driving biotic variables for dragonfly diversity and species composition, with restoration measures affecting submerged macrophyte cover directly but tall sedges indirectly via available sunlight. This study demonstrates that simple restoration measures not only have a positive effect on overall dragonfly diversity, but also increase habitat suitability for several species that would otherwise be absent. We therefore propose dragonflies as a suitable flagship group for pond conservation.