蕨类植物不同孢子裂缝类型在中国的分布格局

孢子在蕨类植物分类及有性生殖过程中具有重要地位, 一般都具有裂缝构造, 常见的是单裂缝和三裂缝, 极少数情况下有多裂缝的变异类型。我们统计了中国蕨类2,281种(含种下单位)的孢子裂缝类型, 来探讨两种不同裂缝类型的分布格局。结果表明: (1)具有单裂缝类型的物种数多于三裂缝类型, 单裂缝与三裂缝物种数目的比值(单/三比)与纬度和海拔呈正相关。随着温度下降以及降水量的降低, 具单裂缝孢子的物种比例增加。推测具单裂缝孢子的蕨类分布范围更广, 更适宜生活在干旱及高纬度或高海拔寒冷地区, 而具三裂缝孢子的蕨类更适宜存在于低纬度或低海拔的温暖地区; (2)蕨类植物孢子裂缝类型不是单次起源, 可能存在平行演化。本研究可以为蕨类植物的起源演化与生态适应等研究提供一定的证据。     

Distributional patterns of the Neotropical humid montane forest avifaunas

The study of biogeographical patterns of the Neotropical humid montane forest avifauna has been prevented due to the lack of phylogenetic hypotheses for most taxa, and to the paucity of detailed studies about the geographical distribution for most of the species. Distributional patterns of this avifauna were explored by integrating predictive distributional models and Parsimony Analysis of Endemicity (PAE). Distributional maps were generated using the Genetic Algorithms for Rule Set Prediction for 442 species; this information was transformed into a data matrix for analysis with PAE. Hierarchical information corresponding to the genus level was incorporated to help resolve the relationships between areas. A strict consensus cladogram showed a clear separation between the Mesoamerican and South American avifaunas. Within the Mesoamerican clade, three geographically structured groups were obtained, whereas the South American clade showed a polytomy of three groups, with two of them, the South Andean Yungas and the Tepuis, located outside the main clade. The third group is a well resolved clade, including areas from eastern Panama and northern Venezuela to central Bolivia. Area relationships suggest a mixed history of dispersal and vicariant events, with the latter being the most important for explaining the biogeographical patterns found.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 175–194.     

The genus sclerospora in India

Summary This paper is a brief review of the work done on 10 valid species ofSclerospora occurring in India and important contributions made to this genus in respect of 1. mode of infection and recurrence of disease, 2. conidial production, 3. proliferation of conidiophores, 4. physiologic specialization, 5. host range and 6. oospore germination.Research Scholar of University Grants Commission.     

Distributional patterns of fishes in an Alaskan Arctic Lagoon

Summary In summer, the fish community of Simpson Lagoon and adjacent coastal waters of the Beaufort Sea was dominated by two marine species (Arctic cod, fourhorn sculpin) and three anadromous species (Arctic and least cisco, Arctic char). The anadromous species remained in the relatively warm and brackish waters near shore and demonstrated an affinity for shoreline edges, particularly the mainland shoreline where species occurrence and catch per unit effort (CPUE) were highest. Spatial segregation was low, presumably reflecting the migratory nature of these species. Marine species were less restricted to nearshore waters in summer and were typically the only species present in winter because anadromous species return to rivers, lakes and deltas to spawn or overwinter. Winter CPUE was low and consisted primarily of Arctic cod and fourhorn sculpin.     

Distributional patterns of sunfishes on the New Jersey coastal plain

Synopsis Sunfishes of the genera Lepomis and Enneacanthus are characteristic inhabitants of quiet waters on the New Jersey coastal plain. In southern New Jersey, E. chaetodon and E. obesus are now almost totally restricted to the Pine Barrens region of the Outer Coastal Plain. In contrast, E. gloriosus is widely distributed. Lepomis gibbosus and L. macrochirus are also widespread, but have established few populations in the more acidic waters of the Pine Barrens. Factor analysis was used to determine underlying patterns of distribution among these 5 species, using 6 habitat variables, measured over 54 collection sites in New Jersey. Two general factors account for 41% of the distributional variation. Habitat variables most strongly associated with factor 1 suggest an underlying trophic gradient (dystrophy to eutrophy) with its associated species. Factor 2 suggests an underlying current-bottom gradient. The basis for the scarcity of Lepomis spp. from acidic waters was explored by examining the tolerance of recently hatched embryos to reduced pH. No increase in mortality was observed at pH 4.25 for L. gibbosus eleutheroembryos and pH 4.5 for L. macrochirus eleutheroembryos. The two species appear to be poorly suited to dystrophic habitats; young Lepomis are primarily planktivores, a dietary niche that is conspicuously reduced in dystrophic waters. Fish of the genus Enneacanthus glean invertebrates on substrate or vegetation, a behavior well suited for dystrophic habitats where most primary and secondary production is associated with aquatic macrophytes and substrate.     

The lichen genus Sclerophyton in India

Abstract:Sclerophyton is reported for the first time from India and two species of this genus, namely S. elegans Eschw. and a new species S. indicum U. V. Makhija & B. A. Adawadkar are recorded.     

Heterochromatin patterns in triatomines of the genus Panstrongylus

Spermatogenesis was analysed by C-banding in two species of triatomines, Panstrongylus megistus and P. herreri. Both species revealed interstitial and terminal bands in the autosomes, which is a common pattern in Heteroptera. The terminal bands corroborated the hypothesis that in holocentric chromosomes the heterochromatin is preferentially located at the telomere. The sex chromosomes in P. herreri were totally heterochromatic in spermatogenesis, and in P. megistus the X chromosomes alternated between positive and negative banding.     

An account of the genus pythium Pringsheim in India

Summary Of the 20 species ofPythium reported from India, not more than seven assume parasitic role inciting mainly diseases in seed bed and sometimes in the fields such as damping-off, seedling blights and foot rots. The paper gives a brief account of the taxonomy of the Indian species and methods of controlling the diseases incited by them.     

Distributional patterns of herpetofauna in monsoon rainforests of the Northern Territory,Australia

Abstract The herpetofauna of 50 monsoon rainforest patches in the Top End of the Northern Territory was surveyed during the dry season of 1990. This fauna contains few obligate monsoon rainforest species, many species which favour this habitat as part of a broad habitat range and a large number of species (indeed most of the regional species pool) that occasionally occur within monsoon rainforests. The taxonomic composition of species favouring monsoon rainforests is a non-random selection from the regional pool, with relatively few species in the families Agamidae and Scincidae occurring commonly in monsoon rainforests. Environmental variation among the rainforest patches sampled was portrayed by ordination, with the first axis corresponding to an environmental gradient from coastal sites to inland rocky rainforests and the second a gradient from relatively dry thickets to tall dense rainforests close to water. The distributions of herpetofauna species were depicted on this ordination space. Most frog species occurred in relatively wet rainforests and most gecko species were relatively restricted to drier rainforests. A substantial component of the herpetofauna was associated with rainforests on rocky substrate. In contrast to this relatively good association with these defined gradients, there was little apparent influence of patch size or level of disturbance on the distribution of individual species of herpetofauna. Sampling month was related to the abundance of many species, with many frog species and some snake and skink species declining (but some skink and one frog species increasing) in abundance in rainforest patches during the late dry season. This seasonal change in abundance is not due to movements from rainforest patches to adjacent vegetation types (or vice versa) but rather to total landscape (cross-habitat) changes in abundance (or detectability). The species composition of patches tended to be idiosyncratic, with substantial variability in composition, even between nearby patches of like environment. Hence it is not possible to nominate a representative rainforest herpetofauna, and indeed a classification of all quadrats (including those from rainforests, rainforest edges and adjacent habitats) based on herpetofauna species composition grouped many non-rainforest quadrats with those from rainforests. There was no rainforest edge herpetofauna assemblage. The herpetofauna from rainforests of the Northern Territory was similar to but somewhat richer than that recorded from the even more attenuated monsoon rainforest area of the Kimberley of northwestern Australia, but shared relatively few species with a sampling from monsoon rainforests from western Cape York. Frog species were more likely to be recorded across these three regions than were snake species. The number of herpetofaunal species per patch was low compared to tropical forests in northeastern Australia, Asia and central America. The long dry season of the Top End may contribute to this impoverishment. However, the small total area of monsoon rainforests in this region, the current scattered network of patches and historical fluctuations in extent and distribution of this habitat are probably at least as important.     

Distributional patterns of vascular plants in Fennoscandia: a numerical approach

The distribution of 725 species and 4 subspecies of vascular plants in 522 grid squares of 50×50 km within Denmark, Finland, Norway and Sweden was analysed by detrended correspondence analysis (DCA) and two-way indicator species analysis (TWINSPAN). Two phytogeographical gradients were recognized: a major gradient running both latitudinally and altitudinally, from southern and lowland areas to northern and mountain districts, and from southerly distributed species to alpine and northerly distributed species, and a secondary gradient running from eastern districts and easterly distributed species to western districts and westerly distributed species. The results are in agreement with previous recognized phytogeographical patterns within the considered area. Possible ecological and historical causes for these patterns are briefly discussed.     

Distributional patterns of mesophilous and thermophilous microfungi in two bahamian soils

This study focuses on the characteristics displayed by mesophilous and thermophilous microfungal populations occurring in two tropical monodominant plant communities, a Cocos nucifera grove and a Casuarina equisetifolia forest, that provide distinctly different edaphic conditions. The mesophilous population sampled at 25°C by the dilution plate method and the thermophilous population that developed on soil plates incubated at 45°C consisted of 1693 isolates representing 60 species and 29 genera and 8887 isolates representing 20 species and 10 genera, respectively. The mesophilous propagules averaged 9,990 per gram dry soil in the coconut grove that lacks a litter layer, is low in moisture and organic matter and is subjected to high solar irradiation. The population was characterized by the prevalence of aspergilli and dematiaceous-sphaeropsidaceous forms and the near absence of mucoraceous isolates. Ascomycetes were common. The only widespread taxa were the three species, Aspergillus niger, Penicillium chrysogenum, and Cladosporium cladosporioides. Species diversity was high and 73% of the isolates were cellulolytic. In the casuarina forest, adequate moisture and organic matter and a protecting litter layer provide a mesic environment. The mean number of mesophilous fungi per gram dry soil was 32,800. This figure is considerably lower than ones reported for mesic temperate communities and may be due to more rapid propagule removal through accelerated microfaunal and microbial activity. An abundance of mucoraceous and moniliaceous isolates and penicillia, and the rarity of aspergilli, dematiaceous-sphaeropsidaceous forms and ascomycetes characterize the population. The infrequency of aspergilli is thought to be due to their poor competitive ability. Eight species, Absidia cylindrospora, Penicillium notatum, Pestalotia cocculi?, Cylindrocarpon heteronema, Gliocladium roseum, Trichoderma viride, Paecilomyces marquandii, and Penicillium funiculosum were widespread in the area. Species diversity equaled that observed in mesic temperate communities. Less than one third of the isolates were cellulolytic. Phytopathogens were common, a feature characteristic of tropical populations. Thermophilous fungi averaged 33 per gram dry soil in the casuarina forest and increased to 943 per gram in the insolated soil of the coconut grove. Thermotolerant forms (94% of the isolates) were abundant and were principally species of Aspergillus and Chaetomium. Thermophilic fungi were rare and of the six species isolated only Chaetomiun britannicum was widespread. Four species, Ch. osmaniae, Ch. medusarum, Ch. sulphureum, and Thielavia arenaria, appear to be new records for western hemisphere soils.     

Distributional patterns of jumping spiders (Araneae: Salticidae) in Australia

Aim To analyse observed and predicted distributional patterns of selected salticid genera in Australia and to examine these distributions in the light of the origins and attributes of the fauna. To detect and compare the locations of regional hotspots when measured using different scales. Location Australia. Methods A total of 4104 locality records for specimens of 51 genera were stored in BioLink. Maps of observed and predicted (using bioclim ) distributions were prepared for each genus. The predicted distributions were combined to provide estimates of the number of genera likely to be found at each locality in the raster and for each of a set of landscape regions across Australia. The predictions were tested by comparing them with independent data sets. Results The Australian salticid fauna consists of radiations based on Oriental, Papuan and possibly Gondwanan forms, plus pantropical and peridomestic species. The predicted distributions of genera fall into a limited number of categories and these reflect the traditional biogeographical regions of Australia. Maximum regional diversity is predicted for central eastern Queensland, though diversity at single locations is highest further south in the New South Wales/Queensland border region. The locations of hotspots are therefore scale dependent. Patterns of distribution are not simply related to particular lifestyles. Fewer genera were predicted from inland Australia; however, recent work has shown that there are a large number of undescribed genera in the drier parts of Australia. The prediction maps allowed lists of genera potentially present in unstudied areas to be developed. Main conclusions (1) The current distribution of genera is predicted by their bioclimatic profiles rather than by their origins or ecology. Some Oriental genera, however, have not reached south‐western Western Australia, though bioclimatic conditions there are predicted to be suitable for them; (2) the highest diversity of genera is predicted to be in south‐eastern Queensland; (3) the results highlight the shortcomings of past fieldwork in Australia, which has concentrated on the areas with higher rainfall; (4) it seems likely that inland Australia will support a large, highly endemic, fauna adapted to the region, and ultimately perhaps 40 or more genera could be found in each region; (5) the results show the possibility of using the maps of predicted distribution of genera not only for biogeographical analyses but also for conservation management and survey purposes.     

Distributional patterns of immature Simuliidae (Diptera) in northwestern North America

SUMMARY. 1. Major landscape features and hydrological parameters indicative of black fly species assemblages were examined at 101 stream sites in Alberta, northern British Columbia, the Yukon and Alaska during the summer. Forty-one black fly taxa were recorded at seventy- nine sites using qualitative sampling procedures. River sites lacking black flies had significantly higher conductivity, greater depth, shallower slope and were farther from the Pacific Ocean than sites with black flies.
2. Classification of sites by taxon occurrence using hierarchical cluster analysis suggested five groupings: A. Simulium tuberosum (Lundstrëm) complex + several taxa. B, S. venustum Saylverecundum Stone and Jamnback complexes + S, tuberosum complex; C. 5. arcticum Malloch complex + S. corbis Twinn complex; D, Gymnopais Stone/ Prosimulium Roubaud; and E. P. onychodactytum Dyar and Shannon complex + several taxa.
3. Multiple discriminant analysis (MDA) was used to predict group membership of the seventy-nine sites using nineteen environmental variables; 71% of the sites were classified correctly. MDA identified latitude and distance from stream source as important factors separating group D from other groups. Stream width and drainage basins entering the Arctic Oeean and Hudson Bay delineated group B. There was no clear separation among groups A. C or E. The presence of sibling species probably accounts for the overlap of black fly assemblages.
4. Our findings are briefly discussed in the context of stream classification systems, notably the river continuum concept.