Diversity and biogeographical relationships of the Australian cestode fauna

The Australian cestode fauna remains poorly documented with a total of 342 species recorded to date. The best-studied host groups are the elasmobranchs and the marsupials, but even in these groups, only 32 and 25% of known host species, respectively, have been examined for parasites. Overall, cestodes have been reported from only 5% of the known vertebrate species. Representatives of virtually all cestode orders and most of the cyclophyllidean families have been recorded from Australia. In spite of these deficiencies, some biogeographical patterns are discernible. In the elasmobranchs, a significant proportion of the known cestodes is endemic while other associations exist with eastern Pacific and Indo-west Pacific faunas. Also identifiable is a group of cosmopolitan species. The nematotaeniids of amphibians suggest Gondwanan affiliations, while the known proteocephalideans, parasitic in reptiles and amphibians, may represent an Asian invasion. Associations of the avian cestodes represent an unexplored but potentially rewarding avenue of biogeographical study. The cestodes of mammals include families with a Gondwanan distribution (Linstowiidae, Hymenolepididae) as well as those (Anoplocephalidae) with an apparent origin in southeast Asia. In addition, a number of genera of cyclophyllidean cestodes (Anoplotaenia, Dasyurotaenia) occurring in marsupials represent biogeographical challenges, not being accommodated within any of the known cestode families. The Australian cestode fauna therefore provides potentially outstanding opportunities for studies of the biogeographical relationships of a number of cestode groups.     

Elevation,space and host plant species structure Ericaceae root-associated fungal communities in Papua New Guinea

Our study aimed to identify significant predictors (spatial distance, elevation, host plant taxonomy) which shape the structure of endophytic fungal (ENDF) and putative ericoid mycorrhizal (ErMF) communities associated with roots of Ericaceae in Papua New Guinea. Roots of five Ericaceae together with one non-Ericaceae species were sampled at an experimental site and one common Ericaceae species was chosen for sampling along an elevation gradient. ENDF and putative ErMF communities were determined using the 454-sequencing approach. ENDF as well as putative ErMF communities were affected by interacting host plant. While the putative ErMF community was structured by host plants at the genus level, the ENDF community was affected by host plant subfamily level. Composition of ENDF as well as putative ErMF communities were affected by elevation. Non-Ericaceae plant species (Hypericum sp.) harbored similar communities of ENDF as well as putative ErMF as Ericaceae plants. Our study provides a first insight into ErMF and ENDF community ecology of Ericaceae in Papua New Guinea.     

Latitudinal, habitat and substrate distribution patterns of freshwater ascomycetes in the Florida Peninsula

Freshwater ascomycetes are important decomposers of dead woody and herbaceous debris in aquatic habitats. Despite evidence of their ecological importance, latitudinal, habitat and substrate distributional patterns of freshwater ascomycetes are poorly understood. In this study, we examined the latitudinal and habitat distributional patterns, and substrate recurrences of freshwater ascomycetes by collecting dead submerged woody and herbaceous debris in lentic and lotic habitats at five selected sites along a north-central-south, temperate–subtropical latitudinal ecotone in Florida. One hundred and thirty-two fungal taxa were collected during the study. Seventy-four were meiosporic and 56 were mitosporic ascomycetes, while two species were basidiomycetes. Canonical analyses of principal coordinates (CAP) and Sørenson’s similarity index of species based on presence/absence data revealed a high turnover in species composition between the northern and southern sites, indicating a change in species composition along the temperate–subtropical latitudinal ecotone of the Florida Peninsula. Results from the ordination analysis indicated that freshwater ascomycete community composition is not significantly different between lentic and lotic habitats in Florida. The geographically broadly distributed species and species commonly found in Florida occurred in both habitats, whereas a number of new or rare species occurred in either lentic or lotic habitats, but not both. The same freshwater ascomycete species did not necessarily occur on both woody and herbaceous debris; of the 132 taxa collected, 100 were reported only on woody debris; 14 species occurred exclusively on herbaceous debris; and 18 species were found on both woody and herbaceous debris in lentic or lotic habitats. Implications of data from this study to the conservation and knowledge of biodiversity for freshwater ascomycetes is discussed.     

普达措国家公园淡水甲壳动物多样性及区系的初步分析

该研究于2011年8月调查了云南普达措国家公园淡水甲壳动物多样性现状。结果表明,该区域共计淡水甲壳动物11科24属29种,其中,拟卤虫属、密刺低额溞和微齿北镖水蚤为国内新记录;枝角类和桡足类为主要淡水甲壳动物类群,占总物种数的82.8%;淡水甲壳动物区系以广布种和古北区物种为主,分别为48.3%和37.9%,特有种为10.4%,东洋区物种仅为3.5%。在此基础上提出了应借鉴"具特殊科学价值地点"的保护方式,对国家公园甲壳动物栖息的水塘环境进行单独保护。     

内蒙古锡林浩特地区嗜盐古菌多样性的研究

从内蒙古锡林浩特地区3个不同的盐湖中共分离到165株古菌,通过ARDRA分析后得到不同的类群,从各个类群中随机选取1~2个代表菌株进行16S rDNA序列测定和系统发育的分析。结果表明分离的菌株分布在Halorubrum,Natronococcus,Natronorubrum,Haloterrigena,Halorhabdus,Halobiforma,Haloarcula,Haloferax8个属和另外两个分支中,表现了锡林浩特地区嗜盐古菌的多样性。部分菌株的16S rDNA序列同源性低于97%,可能是潜在的新属或新种,代表了该地区嗜盐古菌的独特类型。     

Diversity, distribution and biogeography of testate amoebae in China: implications for ecological studies in Asia

Testate amoebae are a group of shelled protozoa that occur in high density populations in wet environments. More than 1900 testate amoebae species or subspecies have been reported in published literature over the last 200 years, from many regions of the world. Testate amoebae are classified as Lobosea or Filosea respectively, according to the presence of lobose or filiform pseudopodia. Testate amoebae have proved an interesting group of indicator organisms in palaeoenvironmental studies and have also been used as bioindicators of human impact on ecosystems. Until recently, the testate amoebae of China were unknown to most western scientists, but our knowledge has improved greatly over the past 20 years. This paper summarizes the testate amoebae research in China along with relevant data from other countries in Asia, and provides the necessary context for future research.     

The biogeographical distribution of microfungi associated with three palm species from tropical and temperate habitats

The microfungi of three palm species were investigated in their natural habitats and in habitats where the palms were cultivated outside their natural ranges. The palms that were selected differed in their habitats and ecology. Archontophoenix alexandrae is endemic to tropical rainforests in Australia, Cocos nucifera is pan‐tropical and Trachycarpus fortunei occurs in warm‐temperate China. Different assemblages of fungi were found in association with palms in temperate regions as compared to those in tropical regions. These differences were more related to climatic influences than to the hosts sampled, as few fungi were host‐species specific. The status of the hosts at the site, i.e. indigenous or introduced, and the degree of disturbance of the habitats within which the palms grew were also influential. When sampled in its natural habitat, Archontophoenix alexandrae had a distinct palmicolous mycota typical of other palms in tropical rainforests. Outside of the palm’s natural habitat, a widely different mycota were recorded that comprised tropical species of a more plurivorous nature. A similar plurivorous assemblage characterized the fungi associated with Cocos nucifera, probably due to the palm’s long history of cultivation. Similarly, plurivorous, but temperate or widespread fungi were associated with Trachycarpus fortunei, both within and outside of its natural habitat. This palm is also highly cultivated. A reduction in palm fungi associated with palms in disturbed habitats has implications for conservation of these fungi. However, it is acknowledged that the data for fungal diversity and distribution is incomplete and fragmentary.     

Diversity patterns in savanna grassland communities: implications for conservation strategies in a biodiversity hotspot

For any conservation strategy to be effective, it must be preceded by knowledge of how diversity is configured within the area of interest. Here, data from 40 savanna-grassland sites were used to examine how plant biodiversity and species composition varied across spatial scales at the Kalakad-Mundanthurai Tiger Reserve (KMTR), south India. Grasslands surveyed contained 278 plant species, and were characterized by high spatial variability in species association patterns. Fourteen distinct community assemblages were identified, organized primarily along an elevation gradient in the reserve. Overall, grasslands at KMTR were characterized by the dominance of a few, widespread species. The bulk of species richness, however, resulted from subordinate species with fairly restricted distributions. At low elevations, grasslands had high species richness and species composition differed greatly between sites. Mid-elevation grasslands contained about half the number of species present at low elevations, but sites were more similar in species composition. Richness of high-elevation grasslands was a third of that found at low elevations, but different sites harbored unique sets of species. Herbivore use of grasslands varied between communities and showed patterns that coincided with elevation. Herbivore use of low-elevation communities was high albeit variable, of mid-elevation sites was consistently low, and increased at higher elevations. Tall grass communities were the least utilized by herbivores at all elevations. Most species surveyed were rare and restricted in their distribution suggesting that conservation efforts must, perforce, encompass the entire reserve. However, differences in the structuring of diversity across elevations, and in herbivore use of grasslands, suggest that conservation efforts can be partitioned differentially across locations, specifically targeting low and high elevation grasslands in the reserve.     

Space-time organization of riverine fish communities in French Guiana

Synopsis A riverine fish assemblage in French Guiana was examined over several consecutive years. Fish distribution was highly structured on at least 3 different scales: between rivers, between the different zones of the rivers and between the different biotopes studied in sampling areas. A temporal organisation of fish communities was also found, superimposed on the spatial structure. The latter was due to the seasonal variations of the water level, and allowed temporary access to flooded areas. The different space-time factors of organisation of fish communities presented here are discussed in regard to their contribution to the maintenance of the observed high species diversity.     

Distribution patterns of Batrachium communities in Mediterranean hard waters

The greatest number of Batrachium plant-communities is reached in base-poor waters of SW Europe where most Batrachium species develop laminar leaves. In contrast, base-rich waters of the Western Mediterranean are characterized by few Batrachium communities and by the only one Batrachium species present in the area with only dissected leaves. This work focused initially on studying the water ecology of Iberian Batrachium communities' developing in hard waters in order to seek to what extend the water physical–chemical gradient determines the occurrence of heterophyllous or homophyllous-dissected species. Floristic data and water physical–chemical data were analyzed using multivariate and comparative methods. We found two main types of Batrachium communities: community of Ranunculus trichophyllus – homophyllous and dissected species–, and community of Ranunculus penicillatus – heterophyllous species–. Alkalinity degree is the main factor separating both communities. Our results of a tentative survey on Batrachium composition in hard waters in the Eastern Mediterranean showed a wider range of physical–chemical water features as well as a greater number of Batrachium species with only dissected leaves in comparison to Western Mediterranean. We conclude that high alkalinity is related to the occurrence of Batrachium communities characterized by species with only dissected leaves in both the western and eastern parts of Mediterranean Europe.     

Viral dynamics and patterns of lysogeny in saline Antarctic lakes

Antarctic lakes are extreme ecosystems with microbially dominated food webs, in which viruses may be important in controlling community dynamics. A year long investigation of two Antarctic saline lakes (Ace and Pendant Lakes) revealed high concentrations of virus like particles (VLP) (0.20–1.26 × 10⁸ ml⁻¹), high VLP: bacteria ratios (maximum 70.6) and a seasonal pattern of lysogeny differing from that seen at lower latitudes. Highest rates of lysogeny (up to 32% in Pendant Lake and 71% in Ace Lake) occurred in winter and spring, with low or no lysogeny in summer. Rates of virus production (range 0.176–0.823 × 10⁶ viruses ml⁻¹ h⁻¹) were comparable to lower latitude freshwater lakes. In Ace Lake VLP did not correlate with bacterial cell concentration or bacterial production but correlated positively with primary production, while in Pendant Lake VLP abundance correlated positively with both bacterial cell numbers and bacterial production but not with primary production. In terms of virus and bacterial dynamics the two saline Antarctic lakes studied appear distinct from other aquatic ecosystems investigated so far, in having very high viral to bacterial ratios (VBR) and a very high occurrence of lysogeny in winter.     

Diversity, adaptation, and endemism in neotropical Ericaceae: biogeographical patterns in the Vaccinieae

In the Neotropics, the Ericaceae are an Andean-centered family, adapted to moist, open, cool montane environments. Overall species richness increases nearer the Equator, with the highest species numbers concentrated in Colombia and Ecuador between 1000 m and 3000 m. There are 46 genera (70% endemic) and about 800 species (ca. 94% endemic) of Ericaceae native to the Neotropics. Five biogeographical regions are recognized for the neotropical Ericaceae, with the greatest species diversity found in the Andes of northwestern South America. Following Pliocene/Pleistocene mountain-building and climatic events, neotropical Ericaceae underwent dynamic speciation and extensive adaptive radiation due to their ecological and life-form plasticity, colonization abilities, adaptation to epiphytic habits, and coevolution with hummingbirds. Given high diversity and singularity within neotropical Ericaceae, along with high levels of habitat alteration, protection of Andean montane ecosystems should become a priority for the conservation of Ericaceae in the Neotropics.

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Resumen  La familia de las Ericáceas en el Neotrópico se concentra en los Andes, adaptada a los ambientes montanosos humedos, de vegetación abierta y fríos. La riqueza total de especies se incrementa a medida que se acerca a la línea ecuatorial, encontrándose el mayor número de especies en Colombia y Ecuador entre 1000 y 3000 msnm. Existen 46 géneros (70% endémicos) y aproximadamente 800 especies (ca. 94% endémicas) de Ericáceas nativas en el Neotrópico. Se reconocen cinco regiones biogeográficas para las Ericáceas neotropicales, siendo los Andes del noroeste de Sur América el lugar de mayor diversidad de especies. Después del levantamiento de las cordilleras y de los eventos climáticos del Plioceno y Pleistoceno, las Ericáceas neotropicales sufrieron una dinámica de especiación y una radiación adaptativa debido a la plasticidad ecológica y de formas de vida, a la capacidad de colonización, de adaptación al epifitismo y a la coevolución con colibríes. Dada la alta diversidad y la singularidad de las Ericáceas neotropicales, así como también los altos niveles de alteración de su hábitat, la protección de los ecosistemas alto-andinos debería ser prioridad en los esfuerzos de conservación en el Neotrópico.

     

Responses to defoliation of species-rich and monospecific tropical plant communities

Summary Floristically rich and monospecific tropical plant communities both responded to partial defoliation with increases in rates of production of new leaf area. Even after 50% of the leaf area had been removed three times, the leaf area increments were still higher in defoliated plots than in controls. Mean leaf area increment after defoliation, on a leaf area per unit ground area basis, was 905 cm² m^-2 d^-1 in diverse successional vegetation and 536 cm² m^-2 d^-1 in a cassava monoculture. Although defoliation stimulated leaf area development, on a per unit ground area basis, in both the cassava monoculture and the successional vegetation, the effect was more pronounced in the successional vegetation. On a per unit leaf area basis, leaf area increments following defoliation in both the diverse successional vegetation and the monoculture were approximately five times those of controls. The diverse plant community continued to respond vigorously after repeated defoliation, while the amount of stimulation of leaf are development in the monoculture declined. Because of their ability to respond even after repeated defoliation, diverse communities may in the long term be more homeostatic with respect to leaf area than are monocultures. The enhanced responsiveness of the species-rich community was due to changes in plant species abundance and very rapid leaf area development by some species.     

Macrobenthic communities in a tropical lagoon (Tahiti, French Polynesia, central Pacific)

Soft bottom communities were sampled quantitatively in Tahiti lagoon (French Polynesia) at 18 stations in five zones around the island over 1 year. In addition, various environmental parameters (silt/clay fractions, organic content, chlorophyll and phaeopigment content) were sampled at the same stations over 2 years. The temporal and spatial variabilities of the macrobenthic communities are described and related to these environmental parameters. Each zone ran from the fringing reef to the inner flat of the barrier reef. The macrofauna exhibited a high richness (392 taxa) with an average mean biomass of 1.8 g AFDW m⁻² (grams ash-free dry weight per square metre). These communities exhibited temporal but not seasonal fluctuations. The biomass of the macrofauna increased from the fringing to the barrier reefs, and the density of individuals was significantly higher on the fringing reefs. Ordination techniques highlighted four groups of stations characterised by distinctive species composition, density and biomass. The first group included stations located on the inner flat of the barrier reef and in the shallow lagoon area and was characterised by highly diverse communities dominated by polychaetes. The second group primarily included stations from the industrial and hotel zones. This group had the lowest diversity and was also dominated by polychaetes, especially the capitellid Dasybranchus sp. 1. The third group was dominated by gastropods and bivalves. The final group of stations was represented only by station 51, in zone 5, which was characterised by mobile soft sediments and wave action and was dominated by the decapod Hippa cf. pacifica. Presumably, these mobile sediments facilitate the development of this benthic community, which does not occur elsewhere in the lagoon. The diversity and biomass of these benthic communities are low compared with most other areas in the South Pacific. Accepted: 10 May 2000     

The annual patterns of photosynthesis in two large, freshwater, ultra-oligotrophic Antarctic lakes

The phytoplankton productivity and biomass of two large, freshwater Antarctic lakes (Vestfold Hills, eastern Antarctica) were investigated over a 12-month period. Crooked Lake was sampled at one site, while Lake Druzhby, a complex lake with two shallow and one deep basin, was subject to a more detailed investigation. Concentrations of chlorophyll a were usually below 1 µg l^-1, indicating ultra-oligotrophic conditions. Despite periodic low nutrient levels, low temperatures (range 0.4-2.8°C) and periodic poor light climate, some degree of photosynthesis was measurable throughout the year, including the dark winter phase. Snow cover had a pronounced impact on the light climate of the water column and inhibited photosynthesis. Mean rates of carbon fixation in the 0- to 15-m water column varied between 0 and 38.47 µg C l^-1 day^-1 in Crooked Lake and 0.24 and 37.68 µg C l^-1 day^-1 in Lake Druzhby. There were significant differences in the seasonal patterns of primary production between the basins of Lake Druzhby. The shallow basins had highest productivity in August, whereas the deep basin had highest rates in summer. Chlorophyll specific rates of photosynthesis or assimilation numbers [µg C (chl. a)^-1 h^-1] varied between 0.05 and 44.9, and photosynthetic efficiency [µg C (chl. a)^-1 h^-1 µmol m^-2 s^-1] between 0.02 and 5.19. The data suggest that the phytoplankton of these lakes is adapted to low irradiance levels, low temperatures and nutrient limitation.     

Diversity and biogeography of testate amoebae

Testate amoebae are amoeboid protists inhabiting a test (shell). They occur globally in soils, wetlands and freshwater, especially peats and mosses. They are of ancient origin, dating from at least the Mesozoic, with possible ancestors as old as the Neoproterozoic. Approximately 2,000 taxa have been described—a number which could easily rise to 4,000 with comprehensive recording. Whilst many protists appear to be cosmopolitan as morphospecies, some of the larger testate species (exceeding 100 μm) have long been considered, controversially, to be geographically restricted. Definitive conclusions have often been confounded by gaps in distributional data and misidentification. Recent increases in recording from previously little known regions, and the rise of molecular taxonomy, have started to resolve outstanding issues—processes still far from complete. Accordingly, biogeographical studies have concentrated on “flagship” species—those which can be identified with certainty and are sufficiently recorded to determine their ecological ranges. Apodera vas (Certes) has been proved to be largely restricted to the Gondwanaland continents and sub-Antarctic islands, but absent from the Holartic despite the availability of much suitable habitat. An early analysis postulated a Mesozoic origin of the species and a distribution influenced by continental drift. Recent molecular evidence could imply a later origin. Either way, its current distribution is clearly influenced by the pattern of global wind currents and lack of lowland tropical habitat. By contrast a “Gondwana-tropical” group of species appears to be restricted to latitudes unaffected by glaciation. Instances of local endemism, such as restriction to a single island, are also known, which await molecular evidence for substantiation. Special Issue: Protist diversity and geographic distribution. Guest editor: W. Foissner.     

Diversity and pharmaceutical screening of fungi from benthic mats of Antarctic lakes

During the MICROMAT project, the fungal diversity of microbial mats growing in the benthic environment of Antarctic lakes was accessed for the discovery of novel antibiotics and anticancers. In all, 160 filamentous fungi belonging to fifteen different genera and 171 yeasts were isolated from 11 lakes, classified and cultivated in different media and at different temperatures. Filamentous fungi were then screened to discover novel antimicrobial and cytotoxic compounds. A total of 1422 extracts were prepared by solid phase extraction of the culture broths or by biomass solvent extraction. 47 (29%) filamentous fungi showed antimicrobial activity; most of them inhibited the growth of gram-positive Staphyloccus aureus (14%), gram-negative E. coli (10%), and of yeasts Candida albicans (11%) and Cryptococcus neoformans (8%). Less activity was detected against representatives of enterobacteria and filamentous fungi. The most productive in terms of bioactivities were cold-tolerant cosmopolitan hyphomycetes such as Penicillium, Aspergillus, Beauveria and Cladosporium. Two bioactive bis-anthraquinones (rugulosin and skyrin) were identified by LC–MS as the main products in a strain of Penicillium chrysogenum isolated from a saline lake in the Vestfold Hills. LC–MS fractionation of extracts from two diverse species of Aspergillus, that exhibited relatively potent antimicrobial activities, evidenced a chemical novelty that was further investigated. To our knowledge, this is the first report of new antibiotics produced by fungi from benthic microbial mats from Antarctic lakes. It can be concluded that these microbial assemblages represent an extremely rich source for the isolation of new strains producing novel bioactive metabolites with the potential to be developed as drugs.     

Diversity of topological digital patterns in Iranian populations

We analyzed bilateral finger prints of 3158 individuals from 13 Iranian populations of diverse origins, for digital patterns, using the topological method. Some male/female differences, and a great deal of heterogeneity in interpopulational variation was observed. Distance analysis, and the resultant dendrograms separated the populations studied, but the separation was not in agreement with the known ethnohistory of this region. Comparison of the obtained results with those based on the traditional methodology showed that the traditional methodology gives better results in measuring population distances.     

Diversity and extinction patterns of permian brachiopoda of South China

The stratigraphical and geographical distribution of 851 brachiopod species from 216 genera and 65 families in the Permian of South China are analysed. It is revealed that the brachiopod diversity underwent two sharp falls during the Permian. The first occurred at the end of Maokouan, accompaning the widely recognised, extensive regression across the Maokouan‐Wujiapingian boundary. Fifty‐seven species of 29 genera survived this first major extinction event. The second sharp reduction of brachiopod diversity took place in the later Changhsingian, with only 17 Permian‐type brachiopod species of 12 genera straggling into the earliest Triassic. Detailed stratigraphic analysis shows that more than 90% of the Changhsingian brachiopod species disappeared at different levels in the Changhsingian before the widely perceived end‐Permian ‘mass extinction’ occurred. It is also notable that each of the step‐wise diversity reduction events was apparently heterochronous. In view of the evidence from lithologies, faunal components and geochemical analyses, the two sharp falls of Permian brachiopod diversity in South China are considered to be closely related to multiple interactions of an environmental deterioration caused by large‐scale regressions.