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A common first step during ecological restoration is reestablishing the local species pool through active reintroduction of individual plant species. Unfortunately, the regional species pool is often far too large to be of practical use during restoration. Methods are needed to produce manageable lists of key species for directed reintroduction. We used life history traits to target species from the regional species pool ( n = 900) for reintroduction to degraded Midwestern oak savanna remnants ( n = 8) in central Iowa, U.S.A. Beginning with the full regional species pool, we first used a priori filters to remove exotic species, species that live in permanently wet habitats, and species already present at the degraded remnant savannas. Next, we created a set of filters to target species with high priority for reintroduction, based on comparisons between the degraded and regional species pools. By this process, we identified perennial forbs and grasses that may be dispersal limited (ant, passive, or heavy wind-dispersed seeds) and are conservative in habitat requirement or have affinities for high-light environments. By applying these filters, we were able to winnow down the regional species pool to a manageable number of species ( n = 111) that we recommend for initial reintroduction efforts to the degraded savanna remnants. Furthermore, we specifically targeted members of the regional species pool that could fill under-represented ecological niches at the degraded savanna remnants and discuss potential benefits of adding these species for restoring ecosystem function. 相似文献
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A new species to science, Hypolytrum subcompositus is described from Kodmin in South West Cameroon. The species is distinct from other African species and appears to have no close relatives. It is a fairly large perennial with a short erect rhizome with many crowded leaves at its end, and (below the leaves) 1–3 lateral culms carrying reduced leaves and a terminal cinnamon-whitish rather congested inflorescence. 相似文献
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Don J. Brenner Arnold G. Steigerwalt G. W. Gorman Robert E. Weaver James C. Feeley L. G. Cordes Hazel W. Wilkinson Charlotte Patton Berenice M. Thomason Karen R. Lewallen Sasseville 《Current microbiology》1980,4(2):111-116
Deoxyribonucleic acid (DNA) relatedness was used to distinguish strains ofLegionella-like organisms (LLO) fromLegionella pneumophila. Two of these LLO strains, WIGA and MI 15, showed sufficient DNA relatedness to one another to be classified in the same
species. The nameLegionella bozemanii species nova is proposed for this new species. The type strain ofL. bozemanii is WIGA (=ATCC 33217) Two other LLO strains, NY 23 and Tex-KL, were shown to represent a new species. The nameLegionella dumoffii species nova is proposed for this species. The type strain ofL. dumoffii is NY 23 (=ATCC 33279). These two species joinL. pneumophila andL. micdadei in the genusLegionella. 相似文献
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Two species of Strobilomyces (Boletaceae, Boletales), S. seminudus and S. hongoi sp. nov. from Japan
We describe and illustrate two Strobilomyces species, S. seminudus and S. hongoi sp. nov. These two species have been confused and treated as a single species (i.e. S. seminudus). However recent studies based on population genetics have implied that they are reproductively isolated. In the present study we found that they are phylogenetically and morphologically distinct. The molecular phylogenetic trees inferred from the partial sequences of the largest subunit of RNA polymerase II (RPB1) and the second-largest subunit of RNA polymerase II (RPB2) support the differentiation of these two species as well as their differentiation from other related species. Strobilomyces seminudus is characterized by a stipe with an annular zone, becoming distinctly thickened near the apex and mottled with appressed-tomentose scales near the base. In contrast S. hongoi is characterized by a stipe with a remarkable reticulum at the upper and middle part and with minutely warty scales downward. Stipe characteristics also are useful for distinguishing these two species from other related species. In addition the incompletely reticulated basidiospores of these two species are also distinct from those of related species (i.e. S. foveatus). 相似文献
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报道斑痣盘菌科的两个寄生种,即生于茶树Camelliasinensis(L.)Kuntze枝梢上的硬湿皮盘菌新种HypoheliondurumY.R.Lin,C.L.Hou&S.J.Wangsp.nov.和生于青杄PiceawilsoniiMast.针叶上的线孢小沟盘菌新组合Lirulafiliformis(Darker)Y.R.Lin&S.J.Wangcomb.nov.。湿皮盘菌属HypohelionJohnston同时为中国新记录属。对此二种进行了汉文描述、图解和讨论,新种附有拉丁文特征简介。供研究标本保藏于安徽农业大学森林保护教研室(AAUFP)。 相似文献
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Specimens from the exsiccatae Phycotheca BorealiAmericana number 698 are shown to represent two distinct species. One of them, formerly known as Callithamnion halliae, is transferred to Aglaothamnion on the basis of its uninucleate cells. The specimens exhibit distichous branching and are ecorticate. A lectotype is proposed for one of the P.B.-A. #698 specimens displaying these characters . Aglaothamnion halliae ( Collins) comb. nov. is an earlier name for Aglaothamnion westbrookiae Rueness et L'Hardy-Halos. The second species, together with specimens of P.B.-A. #1896, has radial branching and corticated axes and is described herein as a new species , Aglaothamnion collinsii. The binomial Aglaothamnion boergesenii ( Aponte et Ballantine ) L'Hardy-Halos et Rueness in Aponte, Ballantine, et J. Norris is validated. A key to the tropical and warm-temperate western Atlantic species of Aglaothamnion is presented . 相似文献
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本文是中国蹄盖蕨属植物研究的系列论文的第三篇,对国产轴果蹄盖蕨系植物进行了分类学订正,详细记载了中国产该系植物11种,首次将20余个名称归入该系的一些种下做为异名处理。轴果蹄盖蕨系植物是蹄盖蕨属中自然的一群,以其铁角蕨类型的孢子囊群和囊群益与其它属下类群相区别。本系植物分布于亚洲热带和亚热带山地,常见于山地常绿阔叶林下,海拔500~1800m。在华中和华东地区其分布区北界不超过长江一线。中国西南地区和台湾及日本为该系的三个分化中心。 相似文献
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Morgan-Ryan UM Fall A Ward LA Hijjawi N Sulaiman I Fayer R Thompson RC Olson M Lal A Xiao L 《The Journal of eukaryotic microbiology》2002,49(6):433-440
The structure and infectivity of the oocysts of a new species of Cryptosporidium from the feces of humans are described. Oocysts are structurally indistinguishable from those of Cryptosporidium parvum. Oocysts of the new species are passed fully sporulated, lack sporocysts. and measure 4.4-5.4 microm (mean = 4.86) x 4.4-5.9 microm (mean = 5.2 microm) with a length to width ratio 1.0-1.09 (mean 1.07) (n = 100). Oocysts were not infectious for ARC Swiss mice, nude mice. Wistar rat pups, puppies, kittens or calves, but were infectious to neonatal gnotobiotic pigs. Pathogenicity studies in the gnotobiotic pig model revealed significant differences in parasite-associated lesion distribution (P = 0.005 to P = 0.02) and intensity of infection (P = 0.04) between C. parvum and this newly described species from humans. In vitro cultivation studies have also revealed growth differences between the two species. Multi-locus analysis of numerous unlinked loci, including a preliminary sequence scan of the entire genome demonstrated this species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further support for its species status. Based on biological and molecular data, this Cryptosporidium infecting the intestine of humans is proposed to be a new species Cryptosporidium hominis n. sp. 相似文献
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MARTIN L. CODY 《Austral ecology》1994,19(2):206-219
Abstract Data are presented from bird censuses at 20 mulga (Acacia aneura) sites across Australia. Null (binomial) models show that community composition is far more consistent among censuses than is expected by a random drawing from all candidate species. By denning and using the designations ‘core species’, ‘peripheral species’, and ‘casual species’, it was shown that 32% of the total 81 bird species censused constituted core species and core niches that account for nearly 75% of the bird density in mulga bird communities countrywide. A minor proportion of the variation in the mulga censuses was attributable to geographic variation in vegetation structure, related to the β-component of diversity. Some mulga niches have regional replacements that contribute to a species turnover among sites and to the γ-diversity of the species set; other species of sporadic occurrence are attributable to the geographic position of the mulga site in terms of adjacent habitats (mostly eucalypt woodland and mixed acacia scrub), a ‘spillover’ effect. Regional variations in the composition of some specific guilds, namely ‘crows’, ‘wrens’, ‘butcherbirds’, foliage insectivores, ground-foraging insectivores, perch-and-pounce foragers and mid-sized, ground-foraging omnivores, are analysed in some detail to illustrate factors that contribute to a large species total in mulga, despite the predominance of core species. 相似文献
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Psephellus yusufeliensis O. Tugay & Uysal sp. nov. (Asteraceae) from Yusufeli (B7 Artvin-Turkey) is described and illustrated. It is closely related to P. aucheriana (DC) Wagenitz & F. H. Hellw. Diagnostic morphological characters are provided and the relationship to other Psephellus species in Turkey is discussed. The geographical distribution of the new species and other related species are mapped. Notes are also presented on the ecology, biogeography and conservation status of the new species. 相似文献
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毛茛科金莲花亚科植物的地理分布 总被引:11,自引:1,他引:10
本文对毛茛科金莲花亚科各属的地理分布作了分析,该亚科植物除了少数属的一些种分布到南半球的温带地区,一些种分布或延伸到亚热带山地、非洲东部和北部的干旱、半干旱的地区外,绝大部分的属、种均分布于泛北极区域。根据其17个属的地理分布式样,把它们划分为8个分布区类型:(1)北温带分布类型4属;(2)北温带和非洲分布类型1属;(3)北半球温带和南半球间断分布类型1属;(4)欧洲和东亚间断分布类型1属;(5)西亚分布类型1属;(6)地中海分布类型3属;(7)欧亚和温带亚洲分布类型1属;(8)东亚分布类型5属。本文以形态特征为主,结合花粉和染色体的性状分析,认为东亚特有的鸡爪草属、Megaleranthis和铁破锣属可能分别是联系驴蹄草属和金莲花属,鸡爪草属和金莲花属以及金莲花族和升麻族的中间类型。另外,文中详细地统计了该亚科的不同等级分类群及特有种在各个植物区的分布,并从系统发育的观点讨论了各个植物区所具有的原始类群和进化类群,提出了如下论点,即东亚植物区(特别是中国西南部)不但是金莲花亚科植物分布的多度和多样性中心以及特有类群的分布中心,而且还是原始类群的保存中心,伊朗-土兰区及地中海周围是第二分布中心。 相似文献
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Q P Wang W J VanDusen C J Petroski V M Garsky A M Stern P A Friedman 《The Journal of biological chemistry》1991,266(21):14004-14010
The alpha-ketoglutarate-dependent dioxygenase, L-asp(L-Asn)-beta-hydroxylase which posttranslationally hydroxylates specific aspartic acid (asparagine) residues within epidermal growth factor-like domains was purified from bovine liver and characterized. A 52-kDa and a 56-kDa species of this enzyme, which accounted for 60 and 30% of the total enzymatic activity, respectively, were purified to apparent homogeneity. Amino-terminal sequence analyses and immunoblots utilizing antisera raised to the intact 52-kDa species as well as to two complementary fragments of this species demonstrated that the 52- and 56-kDa species differ by a 22-amino acid amino-terminal extension. The remaining 10% of the purified enzymatic activity could be accounted for by the presence of immunologically related higher molecular mass forms (56-90 kDa) of L-Asp(L-Asn)-beta-hydroxylase. Strong evidence was obtained from the results of immunoextraction studies that L-Asp(L-Asn)-beta-hydroxylase can be identified with the purified proteins. Kinetic and physical studies suggest that L-Asp(L-Asn)-beta-hydroxylase exists as a monomer with a compact catalytic domain and an extended protease-sensitive amino terminus whose function remains to be determined. Since the purified L-Asp(L-Asn)-beta-hydroxylase hydroxylated both L-Asp- and L-Asn-containing substrates, it is possible that a single enzyme is responsible for the hydroxylation of Asp and Asn residues in vivo. 相似文献
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To investigate genomic relationships of Elymus tschimganicus (Drobov) Tzvelev (2n = 6x = 42, S1S2Y genomes) and E. glaucissimus (M. Pop.) Tzvelev (2n = 6x = 42, S1S2Y genomes), interspecific hybridizations of the two target species were carried out with 27 other Elymus species containing the SH, SY, SYH, SYP, SYW, and SH1H2 genomes, respectively, collected from different geographic regions. Chromosome pairing behavior was analyzed at metaphase I in 27 hybrids representing 23 hybrid combinations, and overall genomic relationships of the two target species with the other Elymus taxa were estimated. The study concluded that (i) interspecific hybridization was principally easy to perform between the Elymus species, but no general pattern of crossability was obtained, and all hybrids were completely sterile, (ii) the two species have a similar meiotic pattern in their hybrids with the other Elymus species, and (iii) species containing the SY, SYP, and SYH genomes have a generally higher level of genomic homology to the target species than those possessing the SH genomes, and the South American hexaploid with the SH1H2 genomes has the lowest level of genomic homology to the two target taxa. 相似文献
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The frequency and types of repetitive nonsatellite DNA of two sibling species of the repleta group of Drosophila, D. buzzatii, and D. koepferae have been determined. For each species, the analysis is based on a sample of more than 100 clones (400 kb) obtained from genomic DNA. A theoretical model has been developed to correct for the presence of a mixture of repetitive and unique DNA in these clones. After correction, a high content of repetitive DNA has been demonstrated for both species (D. buzzatii, 19-26%; D. koepferae, 27-32%). The repetitive sequences have been classified according to their hybridization pattern when used as probes against genomic DNA and by their in situ hybridization signals on polytene chromosomes. Data suggest that the main nonsatellite component of these species is simpler and more repetitive than that of D. melanogaster, pointing to a wide variability in content and class size distribution of repetitive DNA among Drosophila species. 相似文献
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The genus Thecotheus is reported in Australia for the first time. A new species, Thecotheus urinamans is described and illustrated and included in a key to all known species of the genus. Critical macro- and micromorphological comparisons are presented to distinguish the new species from several closely related species, particularly the widespread fungus Thecotheus crustaceus. Thecotheus urinamans was growing on rotting, moist, plant litter from an experimental plot treated with urea (ammonia) in the indigenous jarrah (Eucalyptus marginata) forest of Western Australia. 相似文献