Influence of environmental conditions on the distribution of Central Asian green toads with three ploidy levels

We studied the distribution of Palearctic green toads (Bufo viridis subgroup), an anuran species group with three ploidy levels, inhabiting the Central Asian Amudarya River drainage. Various approaches (one‐way, multivariate, components variance analyses and maximum entropy modelling) were used to estimate the effect of altitude, precipitation, temperature and land vegetation covers on the distribution of toads. It is usually assumed that polyploid species occur in regions with harsher climatic conditions (higher latitudes, elevations, etc.), but for the green toads complex, we revealed a more intricate situation. The diploid species (Bufo shaartusiensis and Bufo turanensis) inhabit the arid lowlands (from 44 to 789 m a.s.l.), while tetraploid Bufo pewzowi were recorded in mountainous regions (340–3492 m a.s.l.) with usually lower temperatures and higher precipitation rates than in the region inhabited by diploid species. The triploid species Bufo baturae was found in the Pamirs (Tajikistan) at the highest altitudes (2503–3859 m a.s.l.) under the harshest climatic conditions.     

Abundance,richness and composition of lianas in forest communities along an elevation gradient in New Caledonia

Background: Lianas are an abundantand dynamic component of tropical forests, and their abundance ispredicted to increase with global change. A better understandingof factors that explain their distribution is required, especially onoceanic islands for which few data are available.

Aims: Identifythe environmental factors that shape liana communities in NewCaledonian forests

Methods: We studied liana abundance,basal area, richness and climbing modes in 27 forest plots (20m × 20 m) along an elevation gradient (sea level to ca. 1000 ma.s.l.) that covers different forest types and precipitation regimes.

Results: We inventoried 992 lianas belonging to 71 species. The abundance and basal area decreased logarithmically withincreasing elevation while species richness tended to peak at midelevations.Twining lianas were the most abundant and species-richfunctional group. We found no clear relationship between climbingmodes and forest structure.

Conclusions: Our results show thatliana abundance decreases with increasing elevation in responseto lower precipitation in seasonal dry forest. At high elevation (600–1000 m a.s.l.), climbing secondary hemi-epiphytes replace lianasprobably as a result of climate-based niche differentiation. Variationof species richness along the gradient could not be explained byprecipitation or by forest structural parameters.     

Reappearance of Eumarcia fumigata (G.B. Sowerby II, 1853) (Bivalvia: Veneridae) into the Swan River,Western Australia

ABSTRACT

The venerid bivalve Eumarcia fumigata was a common species in Western Australia (WA) during the Pleistocene, where it was distributed as far north as Shark Bay. It became extinct in WA as the climate changed several thousand years ago but remains common in eastern Australia from southern Queensland to South Australia and Tasmania. The species has recently reappeared in the Swan River, probably due to shipping movements. Of the > 60 marine and estuarine species introduced into WA it is only the third confirmed introduction from eastern Australia, and the first that is a reappearance in the Swan River of a species present in the geological past. The present reappearance of E. fumigata, and the introduction of other species, has been made possible by the removal of a rocky bar at the mouth of the estuary and the creation of more marine conditions in the lower Swan estuary.     

Histological studies to evaluate gonad development in Barbus neefi (Cyprinidae), the sidespot barb,from South Africa

Barbus neefi gonads were collected seasonally from specimens from the Selati and Makutsi Rivers, tributaries of the Olifants River in Limpopo and Mpumalanga provinces, South Africa, preserved in 4% formalin solution and stained with hematoxilin/eosin. These collections represent new records for this species in these rivers. Mature eggs and sperm were found to occur throughout the year in most individuals (SL 22.7–67.2mm), as occurs in other cool water species. One individual was hermaphrodite.     

Ecological responses of two pioneer species to a hydrological connectivity gradient in riparian forests of the lower Paraná River

The vegetation of the Paraná River floodplain has physiognomic, structural and ecological characteristics that are distinct from those of the surrounding landscapes across the river (Forest, Chaco Savannahs, Pampean steppe). Few species are able to live in the alternately flooded and dry soil. The distribution of each species is strongly conditioned by the water regime in each area of the floodplain, and its location in the topographical gradient of the islands allows us to determine the possibility of colonising the bars and islands of the river course to determine their tolerance to hydrological variations and to foresee the changes that can take place as a result of disturbances in the hydrological regime. Here, we present the occurrence of willow (Salix humboldtiana Willd.) and South American alder (Tessaria integrifolia Ruiz et Pav.) in bars and islands of different topographies in a section of the Paraná River downstream from the confluence of the Paraguay and Paraná rivers. The results indicate that both species have similar niches in relation to hydrological fluctuations. However, willow was significantly more frequent at of 48.49 m a.s.l., while palo bobo reached its highest frequency at 49.29 m a.s.l. The difference between the modes of the distribution curves of each species was 0.80 m. Canopy trees such as willow and palo bobo are adapted to flooded soil conditions for 77.8 and 40% of their respective lives and survive with a long-lasting inundation phase (306 and 366 days, respectively). However, many trees in the Paraná River floodplain died when the flood period extended for more than 1 year.     

On Cannabis indica,Indian hemp

Background: The South Aegean Volcanic Arc (SAVA), one of the most notable geological structures of the Mediterranean Sea, is floristically well known. Nevertheless, the factors that contribute to shaping the plant species richness of the SAVA remain unclear.

Aims: To investigate the factors that affect plant species richness and identify plant diversity hotspots in the SAVA and other central Aegean islands.

Methods: We used stepwise multiple regression to test the relationship between a number of environmental factors and plant species richness in the SAVA, as well as the residuals from the species–area linear regressions of native, Greek and Cycladian endemic taxa as indicators of relative species richness.

Results: The area was confirmed to be the most powerful single explanatory variable of island species richness, while geodiversity, maximum elevation and mean annual precipitation explained a large proportion of variance for almost all the species richness measures. Anafi, Amorgos and Folegandros were found to be endemic plant diversity hotspots.

Conclusions: We have demonstrated that geodiversity is an important factor in shaping plant species diversity in the Cyclades, while mean annual precipitation, human population density and maximum elevation were significant predictors of the Greek endemics present in the Cyclades. Finally, Anafi was found to be a plant diversity hotspot in the South Aegean Sea.     

Light,temperature and flow regimes of the Vaal River at Balkfontein,South Africa

A detailed investigation into light, temperature and flow regimes of the Vaal River was done for the first time. The Vaal River is ecologically and economically one of the most important rivers in South Africa. In a South African context, the Vaal River, with an average Secchi disk depth (Z _sd) of 0.41 m and an average euphotic zone depth (Z _eu) of 1.3 m, is a moderately turbid system. Red light (approx. 670 nm) penetrated Vaal River water to a greater degree than other components of the light spectrum. Water temperature in the Vaal River (min. = 10, max. = 27 °C at midday), closely followed seasonal changes in average atmospheric temperatures. The water-column shows little temperature stratification. The Vaal River is a highly regulated system with relatively high discharge rates at Balkfontein (average 112 m³ s^–1), but relatively low current velocity (approx. 0.35 m s^–1). Discharge was the most important variable to influence transparency of Vaal River water. Higher discharge resulted in higher total suspended solids (TSS) concentration and higher extinction coefficient (k) values as well as in higher turbidity and thus in lower Z _eu and Z _sd. From the mean TSS (141 mg l^–1) it was calculated that the Vaal River (mean annual run-off of 3532 million m³) transported 498016 tonnes of suspended solids per annum.     

Genetic structure along an altitudinal gradient in Lippia origanoides,a promising aromatic plant species restricted to semiarid areas in northern South America

The genetic diversity and population structure of Lippia origanoides, a species of the Verbenaceae family that shows promise as a crop plant, was investigated along an altitudinal gradient in the basin of the Chicamocha River in northeastern Colombia. The economic importance of the species, quality of its essential oils, and the fact that it is restricted to some few semiarid areas in northern South America may put the species at risk in a scenario of uncontrolled harvest of natural populations. Lippia origanoides was sampled along an altitudinal gradient from 365 to 2595 m.a.s.l. throughout Chicamocha River Canyon, a semiarid area in northeastern Colombia. Genetic diversity was assessed by means of AFLP markers. The number of AFLP loci (355) and the number of individuals sampled (173) were sufficient to reliably identify four populations at contrasting altitudes (F_ST = 0.18, P‐value < 0.0000), two populations in the lower basin, one population in the medium basin, and one population in the upper basin, with a low level of admixture between them. In average, genetic diversity within populations was relatively high (Ht = 0.32; I = 0.48); nevertheless, diversity was significantly reduced at higher altitude, a pattern that may be consistent with a scenario of range expansion toward higher elevations in an environment with more extreme conditions. The differences in altitude among the basins in the Chicamocha River seem to be relevant in determining the genetic structure of this species.     

The Southern Churchill, Petrocephalus Wesselsi, a New Species of Mormyrid from South Africa defined by Electric Organ Discharges, Genetics, and Morphology

East African and south African churchills (Petrocephalus, Mormyridae) were synonymised in 1959 to become members of a single species of subcontinental, southern African distribution, Petrocephalus catostoma (Günther, 1866). By comparison with the type material for P. catostoma from the Ruvuma River and P. stuhlmanni from the Ruvu River, both of East African origin, we confirm the South African form of churchill to represent a new species, P. wesselsi, ranging from the northern Limpopo and Incomati systems south to the Pongola River (Natal) as its southern limit. We also compared churchills from the Sabie River (25° S, South Africa, Incomati system) with churchills from the Upper Zambezi River (17° S, Namibia), using electric organ discharges (EODs) and morphology. The duration of an EOD pulse of the South African form (N = 39; 943.2±S.E. 18.82µs) is, on average, more than twice that of the Upper Zambezi form (N = 37; 436.6±15.1µs), and the amplitude of the second head-positive phase (P2 phase relative to P1 = 1) significantly weaker (0.133 ± 0.0005 vs. 0.472 ± 0.002 for Upper Zambezi males, 0.363 ± 0.03 for Upper Zambezi females). In contrast to the Upper Zambezi form, the EOD of the South African form exhibits no difference between the sexes. Fish from the two origins differ significantly in 11 out of 14 anatomical characters studied, confirming molecular genetic differentiation on the species level.     

Conifer seedling recruitment across a gradient from forest to alpine tundra: effects of species,provenance, and site

Background: Seedling germination and survival is a critical control on forest ecosystem boundaries, such as at the alpine–treeline ecotone. In addition, while it is known that species respond individualistically to the same suite of environmental drivers, the potential additional effect of local adaptation on seedling success has not been evaluated.

Aims: To determine whether local adaptation may influence the position and movement of forest ecosystem boundaries, we quantified conifer seedling recruitment in common gardens across a subalpine forest to alpine tundra gradient at Niwot Ridge, Colorado, USA.

Methods: We studied Pinus flexilis and Picea engelmannii grown from seed collected locally at High (3400 m a.s.l.) and Low (3060 m a.s.l.) elevations. We monitored emergence and survival of seeds sown directly into plots and survival of seedlings germinated indoors and transplanted after snowmelt.

Results: Emergence and survival through the first growing season was greater for P. flexilis than P. engelmannii and for Low compared with High provenances. Yet survival through the second growing season was similar for both species and provenances. Seedling emergence and survival tended to be greatest in the subalpine forest and lowest in the alpine tundra. Survival was greater for transplants than for field-germinated seedlings.

Conclusions: These results suggest that survival through the first few weeks is critical to the establishment of natural germinants. In addition, even small distances between seed sources can have a significant effect on early demographic performance – a factor that has rarely been considered in previous studies of tree recruitment and species range shifts.     

Changes in the algal composition and water quality of the Sundays River,Karoo, South Africa,from source to estuary

A first survey was done on algae present in the Sundays River from its source to its confluence with the sea. Species found in the upstream sections of the river included indicators of good water quality, but the quality deteriorated downstream with peaks in algal abundance being ascribed to peaks in nutrient concentrations. Cyanobacteria and euglenoids were present in the upper and middle reaches of the river, but were absent downstream. Dinoflagellates became more important downstream, especially in the estuary. Dominant species, reaching high concentrations along the river, included Nitzschia frustulum, Nitzschia capitellata, Carteria klebsii, Chlorella vulgaris and Anabaena species. The presence of the diatom Eolimna comperei is a first record of its occurrence in South Africa. The Sundays River can be described as a brackish, hard water system with high nutrient concentrations in certain sections. The most important contributors to high nutrient concentrations were point sources in the vicinity of towns along the river banks, as well as diffuse sources contributing to high nitrogen concentrations in the fertile Sundays River valley. Increasing salinities were due to pollution, evaporation and agricultural activities in the valley.     

The Maloti minnow Pseudobarbus quathlambae (Barnard, 1938) is not extinct in South Africa

Despite concerted surveys, the Maloti minnow Pseudobarbus quathlambae (Barnard 1938) had not been recorded in South African waters for almost eighty years since the original collections were made at the type locality in the upper uMkhomazana River in 1938. The species was therefore declared extinct in South Africa, whereas extant populations were considered confined to various rivers in the Lesotho highlands. In April 2017, however, this species was rediscovered in the Mzimkhulu River system in KwaZulu-Natal. The rediscovery of a species that was considered locally extinct supports the need for extensive surveys to determine its distribution range, estimate population sizes, assess conservation status and implement effective strategies to ensure its continued existence in KwaZulu-Natal.     

The World Crane Action Plan: implications for conservation of cranes and wetlands in Africa

Beilfuss, R.D., Meine, C.D., & Archibald, F.W. 2000. The World Crane Action Plan: implications for conservation of cranes and wetlands in Africa. Ostrich 71 (1 & 2): 227.

The IUCN Species Survival Commission recently published The Cranes: Status Survey and Conservation Action Plan. Prepared over the past three years by the IUCN Crane Specialist Group, the document reviews the status of the world's cranes (Family: Gruidae) and their habitats, summarises recent crane conservation actions, and specifies priority measures for the future. Eleven of the 15 crane species are now proposed for inclusion on the IUCN Red List of Threatened Animals, and several subspecies and populations are critically endangered. Africa supports six species of cranes in 39 countries. The Black Crowned Crane Balearica pavonina, national bird of Nigeria, is resident in western and central Africa. The Grey Crowned Crane B. regulorum, national bird of Uganda, spans eastern and southern Africa. The Wattled Crane Bugeranus carunculahrs, largest and. rarest of Africa's cranes, ranges from Ethiopia to South Africa. The Blue Crane Anthropoides paradiseus, national bird of South Africa, is endemic to South Africa and Namibia. The Demoiselle Crane A. Virgo and Eurasian Crane Grus grus are winter visitors. Cranes have been the focus of intensive captive propagation and reintroduction programs as well as extensive habitat protection efforts. They are also excellent umbrella species for ecosystem-level conservation efforts. Wetlands that provide a home for cranes include the floodplains of the great river systems of Africa, such as Kafue Flats and Zambezi Delta of the Zambezi River system, the Okavango River Delta, the Sudd of the Upper Nile River, the Bangweulu Basin and swamps of the Zaire River system, the Senegal River Delta, and the Inner Niger River Delta, and the wetlands of Lake Chad. Small, isolated wetlands provide vital breeding habitat. This presentation will provide an overview of the action plan for those interested in cranes in particular, as well as those working in ecosystems and regions where cranes occur.     

Tree population dynamics,stand structure and species composition in the montane virgin forest of Vallibäcken,northern Sweden

The population dynamics of Betula pubescens and Picea abies in a boreal forest near Kvikkjokk, northern Sweden, are governed by a process of storm gap regeneration similar to the gap regeneration described for boreo-nemoral forests. Cumulative age distribution curves, interpreted as static survivorship curves, lead to a simple theory of differential survival based on properties of the species, i.e. shade tolerance and relative growth rate. The theory is sustained by diameter and height distributions and by the spatial distributions of logs and of trees in different life-phases. Species of the field and ground layers respond differentially to gap formation and the ensuing successional stages. Browsing by moose (Alces alces) may prevent tree species, mainly Sorbus aucuparia, Betula pubescens and Pinus sylvestris, from developing into a tree layer. The regeneration ability for tree species growing in a stand at 460 m a.s.l. is limited compared with the regeneration at 330 m a.s.l., and typical storm gap formation involving more than one tree seems to occur rarely if at all, while overthrown trees with exposed rootplates are uncommon. Spruce at 460 m a.s.l. shows also a lower growth rate and a lower height/diameter ratio compared to the lower situated stands.     

Radiating in a river: systematics, molecular genetics and morphological differentiation of viviparous freshwater gastropods endemic to the Kaek River, central Thailand (Cerithioidea, Pachychilidae)

Speciation in the context of adaptive radiation is regarded as a key process in the creation of biodiversity. While several lacustrine species flocks provide ideal models for elucidating the underlying evolutionary mechanisms, riverine radiations are both rarely known and studied. The Kaek River, a third‐order tributary of the Nan River and Chao Praya drainage in central Thailand, harbours an exceptional endemic species assemblage of morphologically distinct, viviparous pachychilid gastropods. Our systematic revision, combining a morphological and molecular genetics approach, reveals the sympatric existence of at least seven species of the genus Brotia that is widespread in rivers of South‐east Asia where usually only two species at the most coexist. At eight locations along a 100‐kilometre stretch of the Kaek River, we found the syntopic occurrence of two to three species that are separated by specific habitat preferences and exhibit trophic specialization in their radula morphology. Phylogenetic analyses (using MP, NJ, ML and Bayesian inference statistics) of partial COI and 16S sequence data of 17 samples from six species occurring sympatrically and parapatrically, respectively, in the Kaek River drainage (plus the type species B. pagodula as outgroup) indicate monophyly of all these endemic species. Brotia solemiana, which also occurs in the Loei River, a tributary of the Mekong drainage system, was found to be sister to all other Kaek River pachychilids. The distinctive morphotypes, proposed here to represent biospecies, do not show high levels of genetic variation consistent with long periods of reproductive isolation. This suggests a relatively recent origin of this intrariverine radiation and rapid morphological divergence in the Kaek River Brotia. Recent diversification combined with ecological separation and trophic specialization parallels conditions found, albeit on a more specious level, in the lacustrine species flock of the closely related pachychilid genus Tylomelania, which is endemic to ancient lakes on the Indonesian island of Sulawesi. We discuss and compare the allopatric and ecological aspects of speciation in this unique riverine radiation and outline a putative historical biogeography of the Kaek River species, employing the most recent geological and palaeohydrological data for Thailand. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 82 , 275–311.     

Spatial and temporal variability in intertidal assemblages dominated by the mussel Brachidontes rodriguezii (d’Orbigny, 1846)

The aim of this study is to examine the impact of man’s interventions on the present day distribution of fish in a mountain area in southern Norway, the Atna river system. River Atna originates in the Rondane mountains at altitudes of nearly 1600 m a.s.l., and joins River Glomma at 300 m a.s.l. There are 98 lakes in the watercourse (701–1565 m a.s.l.). Lake Atnsjøen is the largest lake (5.0 km²). Data on the occurrence, origin and status of fish in lakes were obtained by means of interviews, questionnaires and written sources. Occurrence in rivers and streams was surveyed by electrofishing. While the lower reaches of River Glomma contain most of the freshwater fish species found in Norway, the Atna watercourse has a poor fish fauna. Physical conditions, e.g. steep river gradients and several impassable waterfalls have prevented fish from reaching most lakes and river stretches after the deglaciation some 6000 years ago. Five species of fish are regarded as native to the area; brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus), grayling (Thymallus thymallus), Siberian sculpin (Cottus poecilopus) and European minnow (Phoxinus phoxinus). Although only native species are found in the area, the present distribution of these species within the watercourse is to a very large extent a result of human interventions during the past 100–130 years. Brown trout were originally found in the main branch of the river, including Lake Atnsjøen and a few small lakes (n<5) further upstream, but it is now found in 65 lakes. Arctic charr were native only to Lake Atnsjøen, but now inhabit 20 lakes. Grayling remains restricted to River Atna below the waterfall at the outlet of Lake Atnsjøen. The natural distribution of Siberian sculpin is restricted to the main river below Liafossen waterfall (14 km above Lake Atnsjøen). During the 1890s, this species was accidentally introduced to Lake Setningsjøen, and subsequently spread to another three lakes further upstream. The European minnow was native only to the River Atna below Lake Atnsjøen, but was accidentally introduced to seven lakes in the course of this century. There are 24 fishless lakes in the watershed, mainly mountain lakes between 1033 and 1587 m a.s.l.     

The Hiletini, an ancient and enigmatic tribe of Carabidae with a pantropical distribution (Coleoptera)

Abstract. Species of the tribe Hiletini are rarely represented in collections. Of the twenty known species, only three have been adequately collected. These twenty species are here arrayed in two genera, Hiletus (six species in two spe'cies groups), Eucamaragnathus (fourteen species in five species groups). Hiletus species occur in tropical Africa. Eucamaragnathus species of the alluaudi group occur in tropical and southeastern Africa, those of the suberbiei group are found only in Madagascar, those of the bocandei group are found in tropical western Africa, species of the sumatrensis group occur in southeastern Asia (Burma, Vietnam, Sumatra and Borneo), and those of the batesi group are found in the western Amazon Basin, northeastern Amazon Basin, and along the Paraquay River drainage system. Four new species of Hiletini are described from the following type localities: Hiletus nimba, GUINEA, Nimba Mountains; Eucamaragnathus borneensis, BRUNEI, (BORNEO); E.jaws, BRAZIL, Parana; E.amapa, BRAZIL, Territory of Amapa. Most species of Hiletini live in tropical climates with a mean annual temperature above 21°C and mean annual rainfall above 200 cm (exceptions are noted in text). All species apparently frequent latosolic soils in broadleaf evergreen or deciduous forests or in grassland savannahs with scattered or gallery broadleaf evergreen trees. Records available indicate that pupation occurs during the dry season and that adults emerge with the onset of rains. The structure of the mandibles, other mouthparts, crop and proventriculus suggests that only liquid food is normally taken in, and it is probable that at least some preoral digestion occurs as in other carabids. A suite of newly discovered character states associated with the tarsal claws unites the Hiletini with Cnemacanthini, Elaphrini, Migadopini, Promecognathini, Pseudomor-phini, Scaritini and Siagonini. These stocks together form a sister lineage to the ozaenine-brachinine lineage, all having distinct epimera, brushy non-styliform parameres, long empodial unguitractor plates, but not having conjunct mesocoxae (type I). Hiletini is the sister group of the combined Scaritini-Cnemacanthini-Pseudomorphini stocks. We suggest that the origin of the Hiletini occurred at least as early as the Jurassic Period from an equatorial position near the centre of the combined Africa/South America landmass. By mid-Cretaceous, radiation of taxa occurred across southern Laurasia into the southeastern part of that landmass, but never leaving equatorial climates. Later in the Cretaceous or early Tertiary, when continents began their rapid break-up, hiletines were stranded in tropical parts of South America, Africa/Madagascar, and southeastern Asia where they still occur today.     

Relative Distributions of Dreissena bugensis and Dreissena polymorpha in the Lower Don River System,Russia

A survey was conducted in the lower Don River system in Russia to confirm the presence of Dreissena bugensis, and to compare its distribution relative to that of Dreissena polymorpha. In 1999 and 2001–2002, dreissenid mussels were collected at 15 sites in the main river, in connecting reservoirs, and in a major tributary, the Manych River. Collections were made near stations where long‐term monitoring data on total mineral (sum of principal ions) and calcium content were available. Both dreissenid species were found at all sites, with D. bugensis comprising 4–75% of all dreissenids at individual sites. D. bugensis was relatively more abundant than D. polymorpha in the Manych River where total mineral and calcium content was significantly higher than in the Don River, suggesting the two species may have different calcium requirements. Examination of archived samples indicated that D. bugensis was present in the Don River system as early as the 1980s, presenting the unresolved enigma of why D. bugensis has not displaced D. polymorpha as the dominant species as typically found over shorter time periods in other water bodies. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)