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1.
Five species of mouse or forest shrews (Myosorex) are endemic to South Africa, Lesotho and Swaziland, four of which (Myosorex varius, Myosorex cafer, Myosorex longicaudatus and Myosorex cf. tenuis) are associated with montane or temperate grassland, fynbos and/or forest habitats while a fifth (Myosorex sclateri) is associated with lowland subtropical forests. Due to their small size, specialised habitat, low dispersal capacity, high metabolism and sensitivity to temperature extremes, we predicted that, particularly for montane species, future climate change should have a negative impact on area of occupancy (AOO) and ultimately extinction risks. Species distribution models (SDMs) indicated general declines in AOO of three species by 2050 under the A1b and A2 climate change scenarios (M. cafer, M. varius, M. longicaudatus) while two species (M. sclateri and M. cf. tenuis) remained unchanged (assuming no dispersal) or increased their AOO (assuming dispersal). While temperate species such as M. varius appear to be limited by temperature maxima (preferring cooler temperatures), the subtropical species M. sclateri appears to be limited by temperature minima (preferring warmer temperatures). Evidence for declines in AOO informed the uplisting (to a higher category of threat) of the Red List status of four Myosorex species to either vulnerable or endangered as part of a separate regional International Union for Conservation of Nature (IUCN) Red List assessment.  相似文献   

2.
Cortinarius is one of the most species-rich genera of mushroom-forming fungi. Based on phylogenetic and morphological evidence, Cortinarius, sect. Riederi, is introduced at sectional level (= subsect. Riederi sensu Brandrud & Melot). The taxonomy, phylogeny, ecology and distribution of not only mainly European but also including some North American taxa of this section are treated, which includes nine species and two varieties. Of these, three taxa are described as new (C. burlinghamiae, C. pallidoriederi and C. argenteolilacinus var. dovrensis). The sect. Riederi species possess morphological features similar to Phlegmacium group(s) and forms a phylogenetically isolated lineage, with no supported affinity to other phlegmacioid groups. Three taxa are known from both Europe and North America, two species are known only from North America and five only from Europe. Altogether, eight of the ten taxa are associated with conifers or northern (boreal-subalpine) deciduous trees (Betula spp.). Only two species occur in more temperate forests (Fagus forests), and no species have so far been found in thermophilous Quercus forests  相似文献   

3.
Decline and fragmentation of natural habitats, such as old-growth forests, reduces their availability in the landscape. The solution to this problem for many forest-dwelling species, may be colonization of alternative habitats, such as parks, orchards or rural avenues, located in the highly fragmented agricultural landscape. Our main objective was to determine the effect of both habitat quality parameters and isolation from potential forest habitats, as primary habitats, on the occurrence of the hermit beetle (Osmoderma) in rural avenues in south-western Poland. The study was based on the results of an inventory of the species in 201 rural avenues within an area of approx. 30,000 km2. Occurrence of the hermit beetle in such alternative habitats was affected by both habitat quality parameters and connectivity with suitable forest habitats. The species occurrence in an avenue was significantly positively affected by mean tree diameter and diversity of tree species, but probability of occurrence decreased as isolation of avenue from the deciduous forest increased. Moreover, in the study area the hermit beetle seemed to avoid alleys with a large proportion of Acer platanoides, Fraxinus excelsior and Populus spp. Spatially isolated roadside avenues have limited value in the preservation of the hermit beetle in the long term conservation management of the species. Conservation plans in such habitats should therefore take into account surrounding suitable habitats.  相似文献   

4.
Impatiens parviflora is one of the most widely spread invasive species in central Europe, yet the factors affecting its spread are still subject to discussion. The aim of this study was to determine which factors affect the spread of I. parviflora. This was achieved by observing the natural spread of the species on 15 permanent transects, in six different habitats, found within the Czech Republic from 2012 to 2016. The transects were divided into 321 plots, whilst data on environmental conditions, as well as of the spread of I. parviflora and its performance, were collected in each plot. The results showed that individual stages of the I. parviflora life-cycle were affected by individual environmental conditions to different extents. The most important factor preventing seedling emergence and establishment was a high cover of herb layer. It did not, however, affect survival of older plants. Thus, I. parviflora can grow in sites with dense cover of herb layer in case the cover formed after I. parviflora seedlings established. Juvenile mortality was the highest in sites with low nutrient levels and low soil moisture. Canopy openness had a negative effect on I. parviflora performance. Impatiens parviflora performed better in neutral soils, in comparison to acidic soils. Oak-hornbeam forests were the most suitable habitat for I. parviflora, followed by acidophilous oak and mixed coniferous forests. However, I. parviflora was able to penetrate into even species-rich habitats, such as thermophilous oak forests, as well as steppe grasslands on rocks. This makes it a potential threat to biodiversity. Only heathlands found on former pastures proved to be unsuitable for I. parviflora, as these remained uninvaded until the end of the study.  相似文献   

5.
Kelp forests dominate temperate and polar rocky coastlines and represent critical marine habitats because they support elevated rates of primary and secondary production and high biodiversity. A major threat to the stability of these ecosystems is the proliferation of non-native species, such as the Japanese kelp Undaria pinnatifida (‘Wakame’), which has recently colonised natural habitats in the UK. We quantified the abundance and biomass of U. pinnatifida on a natural rocky reef habitat over 10 months to make comparisons with three native canopy-forming brown algae (Laminaria ochroleuca, Saccharina latissima, and Saccorhiza polyschides). We also examined the biogenic habitat structure provided by, and epibiotic assemblages associated with, U. pinnatifida in comparison to native macroalgae. Surveys conducted within the Plymouth Sound Special Area of Conservation indicated that U. pinnatifida is now a dominant and conspicuous member of kelp-dominated communities on natural substrata. Crucially, U. pinnatifida supported a structurally dissimilar and less diverse epibiotic assemblage than the native perennial kelp species. However, U. pinnatifida-associated assemblages were similar to those associated with Saccorhiza polyschides, which has a similar life history and growth strategy. Our results suggest that a shift towards U. pinnatifida dominated reefs could result in impoverished epibiotic assemblages and lower local biodiversity, although this could be offset, to some extent, by the climate-driven proliferation of L. ochroleuca at the poleward range edge, which provides complex biogenic habitat and harbours relatively high biodiversity. Clearly, greater understanding of the long-term dynamics and competitive interactions between these habitat-forming species is needed to accurately predict future biodiversity patterns.  相似文献   

6.
In several surveys in the tropical forests in Thailand, specimens that looked morphologically similar to Metarhizium martiale and Cordyceps variegata, as well as other Metarhizium species were collected and cultured in vitro. A combined phylogeny of several genes including the small (18S) and large (28S) subunits of the ribosomal DNA, elongation factor 1-α (TEF), RNA polymerase II subunits 1 and 2 (RPB1, RPB2) genes has shown these to be new taxa in the Clavicipitaceae. Nigelia is described as a new genus closely related to Metarhizium, to the scale insect pathogens Aschersonia (Hypocrella), Samuelsia and Moelleriella, and to plant pathogens in Claviceps and Balansia, and other relatives. Nigelia comprises M. martiale and a new species Nigelia aurantiaca, which has been found infecting lepidopteran larvae and which produces pseudoimmersed, obliquely arranged, obpyriform perithecia with curved or bent ostioles and with whole (non-separating) cylindric ascospores. Metarhizium chaiyaphumense, M. kalasinense, M. prachinense, M. samlanense, and M. takense are described as new species of Metarhizium. Metarhizium martiale is transferred to Nigelia, and Paecilomyces reniformis is transferred to Metarhizium.  相似文献   

7.
8.
Mitochondrial DNA control region of Mus terricolor, three aboriginal species M. spretus, M. macedonicus, M. spicilegus; the Asian lineage M. caroli, M. cervicolor, M. cookii; and the two house mice, M. musculus domesticus and M. m. castaneus were analysed to estimate the substitution rate, phylogenetic relationship and the probable time of divergence. Results showed that M. spretus, M. caroli and M. terricolor are highly diverged from each other (caroli/terricolor = 0.146, caroli/spretus = 0.147 and terricolor/spretus = 0.122), whereas M. spretus showed less divergence with two house mice species (0.070 and 0.071). Sequence divergence between M. terricolor and the Palearctic group were found to be ranging from 0.121 to 0.134. Phylogenetic analysis by minimum evolution, neighbour-joining, unweighed pair group method with arithmetic mean and maximum parsimony showed almost similar topology. Two major clusters were found, one included the Asian lineage, M. caroli, M. cookii and M. cervicolor and the other included the house mice M. m. domesticus, M. m. castaneus and the aboriginal mice M. macedonicus and M. spicilegus along with M. spretus, forming the Palearctic clade. M. terricolor was positioned between the Palearctic and Asian clades. Results showed that Palearctic-terricolor and the Asian lineages diverged 5.47 million years ago (Mya), while M. terricolor had split around 4.63 Mya from their ancestor. M. cervicolor, M. cookii and M. caroli diverged between 4.70 and 3.36 Mya, which indicates that M. terricolor and the Asian lineages evolved simultaneously. M. spretus is expected to have diverged nearly 2.9 Mya from their most recent common ancestor.  相似文献   

9.
The numbers of dominant shrew species, Sorex araneus and Sorex tundrensis, vary in various altitudinal belts of the Kuznetsk Alatau Ridge. The common shrew is the most abundant in dark-coniferous forests of herbaceous type, i.e. belongs to the mesophyte environmental complex. The greatest numbers of Sorex tundrensis are found in habitats of thinned tree layer with moderate humidification; therefore, this species is categorized xeromesophytic.  相似文献   

10.
Microdochium nivale (Fusarium nivale) was found to be frequently occuring in Poland pathogen of small grain cereals heads, causing symptoms similar to those observed after infection ofFusarium species. In consecutive years since 1985 till 1989 the following percentage of wheat and rye ears infected withM. Nivale and withFusarium head blight symptoms was found: 34%, 21%, 42%, 9%, 46% (wheat) and 57%, 43%, 65%, 4%, 47% (rye) heads.However, in naturally infected rye and wheat samples (kernels and chaff), we did not detect toxins usually present in samples infected with fungi of genusFusarium — such as deoxynivalenol and derivatives. TypicalFusarium trichothecene metabolites were also not present in cultures of 11M. nivale strains, growing 3–5 weeks on rice (45% water content) at 20°C. Cultures of two typical isolates on wheat grain (strain KF 1124) and on rice (KF 245) were found to be non toxic to broiler chickens when present in amount 20–40% in their diet. It can be concluded thatM. nivale (F. nivale) representatives in Poland did not produce toxic metabolites neither under laboratory condition nor after cereal ears infection under field conditions.  相似文献   

11.
Although mutualism between ants and flowering plants is wide spread, ant pollination has not evolved as a major pollination syndrome. So far ant pollination has been reported largely in herbaceous species, growing in warm and dry habitats. While studying pollination ecology of Syzygium species (Myrtaceae), growing in tropical forests of the Western Ghats, India, we observed one of the ant species, Technomyrmex albipes, to be the dominant floral visitor in S. occidentale (Bourd.) Chithra among a range of other insect (species of Xylocopa and Trigona, and Apis cerana) and bird visitors. We studied the role of ant species in pollination when compared to other floral visitors. The fruit set in flowers exclusively visited by T. albipes was significantly higher than those visited by any other visitor. The day and night exclusive pollination experiments allowing only T. albipes indicated diel pollination by T. albipes, which was the only active flower visitor during the night. The breeding system of the species was studied through controlled pollinations. The species is partially self-compatible and exhibits considerable autogamy.  相似文献   

12.
Integration between ecology and biogeography provides insights into how niche specialization affects the geographical distribution of species. Given that rivers are not effective barriers to dispersal in three parapatric species of squirrel monkeys (Saimiri vanzolinii, S. cassiquiarensis and S. macrodon) inhabiting floodplain forests of Central Amazonia, we tested whether forest structure and tree diversity may explain species differences in niche specialization and spatial segregation. We sampled 6617 trees of 326 species in three habitats (high várzea, low várzea and chavascal) used by three Saimiri species, and estimated tree species richness in each of them. For each tree, we measured variables known to influence habitat use in primates, such as crown area and presence of lianas, epiphytes and hemi-epiphytes. We used ANOVA to compare these variables and performed multivariate analyses (NMDS, ANOSIM and SIMPER) to evaluate dissimilarities in forest structure among each habitat inhabited by the three Saimiri species. We identified differences in the tree species richness, crown area and presence of lianas, epiphytes and hemi-epiphytes between the three habitats for all Saimiri species. NMDS demonstrated that areas of high and low várzeas occupied by S. vanzolinii were clearly separated from the other species. We also found that different plant species contributed to dissimilarity among Saimiri ranges. Our findings support the hypothesis that tree community structure may promote niche specialization and spatial segregation among primates. We discuss how these patterns could have been favored by historical changes in forest flood patterns, the evolutionary history of Saimiri spp., and past competition.  相似文献   

13.
Rodent species were assessed as potential hosts of Trypanosoma cruzi, the etiologic agent of Chagas disease, from five sites throughout Texas in sylvan and disturbed habitats. A total of 592 rodents were captured, resulting in a wide taxonomic representation of 11 genera and 15 species. Heart samples of 543 individuals were successfully analyzed by SybrGreen-based quantitative PCR (qPCR) targeting a 166 bp fragment of satellite DNA of T. cruzi. Eight rodents representing six species from six genera and two families were infected with T. cruzi. This is the first report of T. cruzi in the pygmy mouse (Baiomys taylori) and the white-footed mouse (Peromyscus leucopus) for the USA. All infected rodents were from the southernmost site (Las Palomas Wildlife Management Area). No differences in pathogen prevalence existed between disturbed habitats (5 of 131 tested; 3.8%) and sylvan habitats (3 of 40 tested; 7.5%). Most positives (n = 6, 16% prevalence) were detected in late winter with single positives in both spring (3% prevalence) and fall (1% prevalence). Additionally, 30 Triatoma insects were collected opportunistically from sites in central Texas. Fifty percent of these insects, i.e., 13 T. gerstaeckeri (68%), and two T. lecticularia (100%) were positive for T. cruzi. Comparative sequence analyses of 18S rRNA of samples provided identical results with respect to detection of the presence or absence of T. cruzi and assigned T. cruzi from rodents collected in late winter to lineage TcI. T. cruzi from Triatoma sp. and rodents from subsequent collections in spring and fall were different, however, and could not be assigned to other lineages with certainty.  相似文献   

14.
Environmental sampling yielded two yeast species belonging to Microstromatales (Exobasidiomycetes, Ustilaginomycotina). The first species was collected from a leaf phylloplane infected by the rust fungus Coleosporium plumeriae, and represents a new species in the genus Jaminaea, for which the name Jaminaea rosea sp. nov. is proposed. The second species was isolated from air on 50% glucose media and is most similar to Microstroma phylloplanum. However, our phylogenetic analyses reveal that species currently placed in Microstroma are not monophyletic, and M. phylloplanum, M. juglandis and M. albiziae are not related to the type species of this genus, M. album. Thus, Pseudomicrostroma gen. nov. is proposed to accommodate the following species: P. glucosiphilum sp. nov., P. phylloplanum comb. nov. and P. juglandis comb. nov. We also propose Parajaminaea gen. nov. to accommodate P. albizii comb. nov. and P. phylloscopi sp. nov. based on phylogenetic analyses that show these are not congeneric with Jaminaea or Microstroma. In addition, we validate the genus Jaminaea, its respective species and two species of Sympodiomycopsis and provide a new combination, Microstroma bacarum comb. nov., for the anamorphic yeast Rhodotorula bacarum. Our results illustrate non-monophyly of Quambalariaceae and Microstromataceae as currently circumscribed. Taxonomy of Microstroma and the Microstromataceae is reviewed and discussed. Finally, analyses of all available small subunit rDNA sequences for Jaminaea species show that J. angkorensis is the only known species that possess a group I intron in this locus, once considered a potential feature indicating the basal placement of this genus in Microstromatales.  相似文献   

15.
In this study conservation of Castilleja levisecta Greenm., a globally endangered species was addressed through in vitro cryopreservation of shoot tips. In vitro cultures were successfully established using seedlings received from British Columbia, Canada. Shoot tips excised from in vitro propagated plants were cryopreserved using a droplet-vitrification method following optimization of individual protocol steps such as pre-culture, treatment with vitrification solutions, and unloading. The highest plant regrowth after cryopreservation (66%) was achieved when shoot tips were pre-cultured in 0.3 M sucrose for 17 h followed by 0.5 M sucrose for 4 h, incubated in an osmo-protectant solution (17.5% [v/v] glycerol and 17.5% [w/v] sucrose) for 20 min, exposed to vitrification solution A3 (37.5% [v/v] glycerol plus 15% [v/v] dimethylsulfoxide (DMSO) plus 15% [v/v] ethylene glycol (EG) plus 22.5% [w/v] sucrose) on ice for 40 min, and unloaded in 0.8 M sucrose solution for 30 min. Healthy plants were developed from cryopreserved shoot tips and propagated in vitro using nodal segments. Plants derived from in vitro culture and from cryopreserved tissues were successfully rooted and acclimated in a greenhouse with 100% survival rate. Acclimatized plants were reintroduced in a naturalized propagation area at the Conservation Nursery at Fort Rodd Hill, Canada. Twenty of 94 reintroduced plants (21%) survived the transit from lab to field and some had started to flower. This is the first report for cryopreservation of C. levisecta, an important step in conserving and re-introducing this critically imperiled species in nature.  相似文献   

16.
Phylogeographic barriers, together with habitat loss and fragmentation, contribute to the evolution of a species’ genetic diversity by limiting gene flow and increasing genetic differentiation among populations. Changes in connectivity can thus affect the genetic diversity of populations, which may influence the evolutionary potential of species and the survival of populations in the long term. We studied the genetic diversity of the little known Northern rufous mouse lemur (Microcebus tavaratra), endemic to Northern Madagascar. We focused on the population of M. tavaratra in the Loky–Manambato region, Northern Madagascar, a region delimited by two permanent rivers and characterized by a mosaic of fragmented forests. We genotyped 148 individuals at three mitochondrial loci (D-loop, cytb, and cox2) in all the major forests of the study region. Our analyses suggest that M. tavaratra holds average genetic diversity when compared to other mouse lemur species, and we identified two to four genetic clusters in the study region, a pattern similar to that observed in another lemur endemic to the region (Propithecus tattersalli). The main cluster involved samples from the two mountain forests in the study region, which were connected until recently. However, the river crossing the study region does not appear to be a strict barrier to gene flow in M. tavaratra. Finally, the inferred demographic history of M. tavaratra suggests no detectable departure from stationarity over the last millennia. Comparisons with codistributed species (P. tattersalli and two endemic rodents, Eliurus spp.) suggest both differences and similarities in the genetic clusters identified (i.e., barriers to species dispersal) and in the inferred demographic history. These comparisons suggest that studies of codistributed species are important to understand the effects of landscape features on species and to reconstruct the history of habitat changes in a region.  相似文献   

17.
Two new species of Metarhizium, M. bibionidarum and M. purpureogenum are described from Japan. Metarhizium bibionidarum is the phylogenetic sister species of M. pemphigi and a member of the M. flavoviride species complex. It is distinguished morphologically from M. pemphigi by its larger conidia. The species is based on a collection of an infected March fly larva (Diptera: Bibionidae) but is also known to occur on fruit beetle (Coleoptera: Scarabaeidae) encountered in France. Metarhizium purpureogenum was isolated from soil by plating and insect baiting methods and represents a unique phylogenetic lineage placed outside the M. anisopliae and M. flavoviride species complexes. Three isolates of M. purpureogenum excreted a distinctive red-purple pigment into agar medium when co-cultured with M. robertsii or Aspergillus oryzae.  相似文献   

18.
Semi-sessile Mytilus mussels are used as indicators of climate changes, but their geographic distribution is not sufficiently known in the Arctic. The aim of this study was to investigate the taxonomic status and genetic differentiation of Mytilus populations in a Northwest Greenlandic fjord at Maarmorilik, impacted by contaminations from a former mine. In this study, mussels were collected at three sites differing in exposure to environmental factors. A total of 54 polymorphic SNPs found in the Mytilus EST and DNA sequences analyzed were successfully applied to 256 individuals. The results provided the first evidence for the existence of M. trossulus in Greenland. The mussel from M. trossulus and M. edulis taxa are shown to coexist and hybridize in the fjord. The three studied sites were found to differ significantly in the distribution of taxa with a higher prevalence of M. trossulus in the inner fjord. The identified M. edulis × M. trossulus hybrids mostly had a hybrid index score of about 0.5, indicating a similar number of alleles characteristic for M. trossulus and M. edulis. There was a low number of backcrosses between ‘pure’ taxa and hybrids. This newly discovered hybrid zone between the two taxa is unique in comparison with the Canadian populations. As Mytilus mussels in Greenland hitherto have been regarded as the one taxon M. edulis, the results have importance for biogeography and future monitoring and environmental studies.  相似文献   

19.
Harvestmen have a general distribution pattern with more species and higher abundance in forests than in open habitats, as previously verified in mountain Cantabrian areas of northern Spain, of the Orocantabrian Province. The study of harvestmen of the low Cantabrian areas of the adjacent biogeographic Cantabro-Atlantic Province is highly appropriate to determine the influence of biogeographic position on the main diversity parameters and the effect of different land uses on harvestman assemblages. The main types of managed habitats (forest plantations and secondary grasslands), together with natural forests, non-planted young forests, shrublands and habitat boundaries were continuously sampled with seven pitfall traps during 1 year at 28 sites. The harvestman assemblages were classified using six different analyses, and indicator species were identified. The spatial patterns of harvestman diversity in low areas differed from those of mountain areas, although they have 15 species in common. Remarkably, higher average harvestman species richness was measured in low Cantabrian areas than in mountain areas. Shrublands and boundaries were the most species-rich habitats. Forested areas were the poorest in abundance, and were not the habitats richest in harvestman species, though they had higher average richness than mountain Cantabrian forests. Grasslands had a unique harvestman composition with significant extraordinary abundances, in particular of Homalenotus quadridentatus (indicator species of this habitat) and H. laranderas. Interestingly, H. laranderas, Paroligolophus agrestis and Ischyropsalis hispanica, indicator species of some open habitats in low Cantabrian areas, have recently been shown to be indicators of shady forests in mountain Cantabrian territories.  相似文献   

20.
Drosophila incompta belongs to the flavopilosa group of Drosophila, and has a restricted ecology, being adapted to flowers of Cestrum as feeding and oviposition sites. We sequenced, assembled, and characterized the complete mitochondrial genome (mtDNA) of D. incompta. In addition, we performed phylogenomic and polymorphism analyses to assess evolutionary diversification of this species. Our results suggest that this genome is syntenic with the other published mtDNA of Drosophila. This molecule contains 15,641 bp and encompasses two rRNA, 22 tRNA and 13 protein-coding genes. Regarding nucleotide composition, we found a high A?T bias (76.6 %). The recovered phylogenies indicate D. incompta in the virilisrepleta radiation, as sister to the virilis or repleta groups. The most interesting result is the high degree of polymorphism found throughout the D. incompta mitogenome, revealing pronounced intrapopulational variation. Furthermore, intraspecific nucleotide diversity levels varied between different regions of the genome, thus allowing the use of different mitochondrial molecular markers for analysis of population structure of this species.  相似文献   

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