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1.
Two new Peruvian species of Axinaea (Melastomataceae) are described. Axinaea francisco‐cabiesii and Axinaea reginae are small trees, endemic to the cloud forest zone in the northern Andean region of Peru. The border region of Peru and Ecuador is one of the Earth's most biologically diverse areas. The Huancabamba depression of the central Andean Cordillera allows for dispersal of flora and fauna between the Amazon Basin and the Pacific lowlands. Additionally, the region is characterized by a fast transition between the humid mountain forests of the northern Andes and the dry, deciduous forests of the northern Peruvian lowlands, making it a hotspot for endemic species. Field observations indicate that both new Axinaea species have small population sizes, occurring in a very restricted habitat. Axinaea flava was described only a few years ago from the cloud forest – paramo transition zone in southernmost Ecuador between 3400 and 3800 m a.s.l. This small tree is the only yellow‐flowered species of the genus. The original assessment counted about 100 individuals. In the last decade, livestock grazing and widespread burning have intensified in the region, and a new assessment yielded only 10 individuals, four of which were damaged by fire. This puts the species in danger of extinction. We encourage search for other populations in southern Ecuador and northern Peru.  相似文献   

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Six new species of Melastomataceae from Ecuador are described: Miconia renneri from the montane forests in north-western Ecuador; Clidemia longipedunculata from the lowland rainforest in eastern Ecuador, and Miconia oellgaardii, Brachyotum johannes-julii, B. russatum , and B. incrassatum from the upper montane forests and plramos in southern Ecuador.  相似文献   

4.
Flightless insects give a clearer view of former distribution of montane habitat in Africa compared with highly mobile animals as birds and butterflies because passive long distance transport and long distance dispersal can be discounted. Only a few species in the twenty-one genera under study are shared between neighbouring mountains which can be explained in all cases by a Pleistocene lowering of the montane habitat by 850 m. Therefore a montane forest cover connecting the mountains at colder times as suggested by the pluvial theory can be refuted which is in correspondence with palynological findings suggesting a dry corridor between the mountains. No montane refuge for flightless insects can be identified, because the most species-rich mountain of a genus differs among the genera under study. Instead, each mountain served as a species refuge with a stable habitat. The requirement of a smaller habitat compared to vertebrates is indicated by endemic species on each single mountain suggesting pre-Pleistocene speciation which results even in endemic genera to one mountain. Different small patches of suitable habitat on one mountain could also explain the radiations found in some genera of flightless insects. In some genera species are lacking on Mt Kenya which indicates—with the findings of no endemic passerine bird on the mountain—a probably very dry condition during colder times. On Mt Cameroon no species of the flightless insect genera occurring on the Eastern mountains are found. This contrasts with the existing patterns of birds, grasses and butterflies.  相似文献   

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滇南勐宋热带山地雨林的物种多样性与生态学特征   总被引:21,自引:0,他引:21       下载免费PDF全文
 研究了鲜为人知的滇南勐宋地区的原始山地雨林植被, 根据分布生境、群落结构和种类组成特征,可将该山地雨林区分为沟谷和山坡两个类型, 分别定义为八蕊单室茱萸(Mastixia euonymoides)-大萼楠(Phoebe megacalyx)林和云南拟单性木兰(Parachmeria yunnanensis)-云南裸花(Gymnanthes remota)林。该山地雨林的外貌仍以单叶、革质、全缘、中叶为主的常绿中、小高位芽植物组成为特征,层间木质藤本植物仍较丰富,草本高位芽植物和附生植物丰富,但板根和茎花现象少见,属于热带山地垂直带上低山雨林或山地雨林植被类型。与该地区的典型热带季节雨林和赤道热带雨林相比, 勐宋的山地雨林群落中的大、中高位芽植物和藤本高位芽植物比例相对减少, 小、矮高位芽植物和草本高位芽植物比例相对增加,单叶、革质、非全缘叶和小叶比例相对增加,板根现象少见。与中国热带北缘-南亚热带地区(季风)常绿阔叶林比较, 勐宋的山地雨林有较多的附生植物和草本高位芽植物,相对较少的小高位芽植物和矮高位芽植物,小叶比例亦较少,非全缘叶和革质叶比例相对较低。故勐宋山地雨林是滇南热带北缘山地的一种较湿润生境的植被类型, 与所谓的季风常绿阔叶林不同。在物种多样性上,勐宋热带山地雨林在单位面积植物种数上并不比该地区的热带季节雨林低, 物种多样性指数与低丘季节雨林相当,比沟谷季节雨林低, 明显高于季风常绿阔叶林。  相似文献   

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Brassavola inhabits a wide altitude range and habitat types from Northern Mexico to Northern Argentina. Classification schemes in plants have normally used vegetative and floral characters, but when species are very similar, as in this genus, conflicts arise in species delimitation, and alternative methods should be applied. In this study we explored the taxonomic and phylogenetic value of the anatomical structure of leaves in Brassavola; as ingroup, seven species of Brassavola were considered, and as an outgroup Guarianthe skinneri, Laelia anceps, Rhyncholaelia digbyana and Rhyncholaelia glauca were evaluated. Leaf anatomical characters were studied in freehand cross sections of the middle portion with a light microscope. Ten vegetative anatomical characters were selected and coded for the phylogenetic analysis. Phylogenetic reconstruction was carried out under maximum parsimony using the program NONA through WinClada. Overall, Brassavola species reveal a wide variety of anatomical characters, many of them associated with xeromorphic plants: thick cuticle, hypodermis and cells of the mesophyll with spiral thickenings in the secondary wall. Moreover, mesophyll is either homogeneous or heterogeneous, often with extravascular bundles of fibers near the epidermis at both terete and flat leaves. All vascular bundles are collateral, arranged in more than one row in the mesophyll. The phylogenetic analysis did not resolve internal relationships of the genus; we obtained a polytomy, indicating that the anatomical characters by themselves have little phylogenetic value in Brassavola. We concluded that few anatomical characters are phylogenetically important; however, they would provide more support to elucidate the phylogenetic relantionships in the Orchidaceae and other plant groups if they are used in conjunction with morphological and/or molecular characters.  相似文献   

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Evaluation of the lichen flora of the Northern Andes must be based on a restricted number of better-known groups, probably less than 25% of the flora. This is because our knowledge of the taxonomy and distribution of lichens in the Tropics is still very incomplete. In the Andes, the groups with foliose and fruticose growth forms are particularly well represented; the crustose group seems less important. This is in contrast with the surrounding lowlands, where crustose is the dominant growth form. At higher taxonomic levels there is a resemblance in taxonomic composition with the cooler zones of the world, which disappears at the generic or sectional levels. A conspicuous morphological feature is the frequency of foliose lichens with linear, rhizinate, or ciliate lobes, probably an adaptation to very humid conditions. More than half of the species have a wide distribution throughout the Tropics or at least in the Neotropics. Among the more restricted taxa is a humid montane element. At the highest elevations a temperate element is apparent, usually with bicentric distribution in both hemispheres. Perhaps 10% of the species are known only from the region; local endemism is probably very scarce. A few taxa appear to be restricted to Ecuador and southern Colombia or Venezuela; so far, only a single species is known with certainty to be restricted to the humid paramos of Colombia. There are distinct affinities with the lichen flora of southeastern Brazil and the Caribbean-Central American area but not with the adjacent Guayana Highland.  相似文献   

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Caterpillar ensembles were sampled on 16 species of shrubs from the family Asteraceae and the genus Piper (Piperaceae) in open and forest habitats in the Andean montane forest zone of southern Ecuador between August 2007 and May 2009. Trophic affiliations of caterpillars to the host plants were confirmed in feeding trials. Overall, species richness of herbivorous caterpillars was high (191 species across all plants), but varied strongly between ensembles associated with different plant species (2?C96 lepidopteran species per shrub species). Ensembles on Piper species were characterized by low effective species numbers and high dominance of one or two species of the Geometridae genus Eois Hübner. Low species number and high dominance were also found on latex-bearing Erato polymnioides, whereas ensembles on two other Asteraceae species were far more diverse and less strongly shaped by a few dominant species. The observed diversity patterns fit well to the concept that anti-herbivore defenses of plants are the major factors regulating associated insect ensembles. Local abundance and geographic range of host plants appear to have less influence. Lepidopteran species feeding on Asteraceae were found to be more generalistic than those feeding on Piper species. We conclude that caterpillar ensembles on most, but not all, studied plant species are defined by a small number of dominant species, which usually are narrow host specialists. This pattern was more distinct on Piper shrubs in forest understory, whereas Asteraceae in disturbed habitats had more open caterpillar ensembles.  相似文献   

10.
The genus Cymbidium (Orchidaceae) exhibits distinctive ecological diversification and occurs in terrestrial, epiphytic, and lithophytic life forms. One species, Cymbidium macrorhizon , lacks foliage leaves and has a strongly mycoparasitic existence. Correlation between habitat differentiation and anatomical characters was tested for 21 species of Cymbidium and its putative sister groups. Although hypostomaty characterizes the genus, C. canaliculatum shows amphistomaty. Ecological preference of this species indicates that amphistomaty is likely adapted to intensive insolation. Four types of subepidermal foliar sclerenchyma were found. Two forest floor species, C. goeringii and C. lancifolium as well as the mycoparasitic C. macrorhizon , do not have this sclerenchyma. In this genus, development of sclerenchyma is correlated with the degree of epiphytism. Palisade mesophyll evolved in Cymbidium section Cymbidium . As members of this section grow on isolated trees in tropical lowland forests or on rocks, the differentiation of palisade tissue is probably correlated with immigration to high light habitats. With the exception of C. macrorhizon , stegmata were found in leaves and stems of Cymbidium . Furthermore, a few epiphytic species have stegmata in their roots; this is a curious feature rarely found in vascular plants. Subterranean rhizomes characterize terrestrial species, while ageotropic roots are found in some epiphytic species. Cymbidium macrorhizon shows peculiar features such as degeneration of stomata, anomocytic stomata, and lack of stegmata and sclerenchyma. This set of character transformations is probably correlated with the evolution of mycoparasitic existence. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 383–419.  相似文献   

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Two species of Pancheria (Cunoniaceae) described here, Pancheria minima J.C. Bradford and Pancheria ouaiemensis J.C. Bradford, draw attention to a recently recognized biodiversity pattern in New Caledonia. Montane maquis on acidic substrates, especially on the Roche Ouaïème, harbors numerous endemic species and is a rare and globally unique ecosystem. We cite 12 species, most described in the past several years, known only from the Roche Ouaïème in an area less than 10km2. Overall, 27 species are known only from montane maquis and currently not found in a well-protected area. The major local threat to montane maquis habitat is anthropogenic fire, with climate change a possible long-term problem. Those montane maquis species known from one or two localities, occupying very small areas, and with declining habitat quality are critically endangered or endangered based on IUCN Red List criteria. Adding the Roche Ouaïème to the reserve system of New Caledonia is recommended to protect and manage a representative area of montane maquis on acidic substrates. A research strategy is proposed to identify species most at risk, locate possible unknown areas of montane maquis, and update taxonomic knowledge. A review of characters that vary among Pancheria species is provided, and the inflorescence architecture is described and diagramed. Both new Pancheria species occur at upper elevations in shrubby habitats. P. minima is remarkable in that the size of plants, leaves and reproductive parts is highly reduced compared to other known species.  相似文献   

13.
In Ecuador, Tapirus pinchaque is considered to be critically endangered. Although the species has been registered in several localities, its geographic distribution remains unclear, and the effects of climate change and current land uses on this species are largely unknown. We modeled the ecological niche of T. pinchaque using MaxEnt, in order to assess its potential adaptation to present and future climate change scenarios. We evaluated the effects of habitat loss due by current land use, the ecosystem availability and importance of Ecuadorian System of Protected Areas into the models. The model of environmental suitability estimated an extent of occurrence for species of 21,729 km2 in all of Ecuador, mainly occurring along the corridor of the eastern Ecuadorian Andes. A total of 10 Andean ecosystems encompassed ~98% of the area defined by the model, with herbaceous paramo, northeastern Andean montane evergreen forest and northeastern Andes upper montane evergreen forest being the most representative. When considering the effect of habitat loss, a significant reduction in model area (~17%) occurred, and the effect of climate change represented a net reduction up to 37.86%. However, the synergistic effect of both climate change and habitat loss, given current land use practices, could represent a greater risk in the short-term, leading to a net reduction of 19.90 to 44.65% in T. pinchaque’s potential distribution. Even under such a scenarios, several Protected Areas harbor a portion (~36 to 48%) of the potential distribution defined by the models. However, the central and southern populations are highly threatened by habitat loss and climate change. Based on these results and due to the restricted home range of T. pinchaque, its preference for upland forests and paramos, and its small estimated population size in the Andes, we suggest to maintaining its current status as Critically Endangered in Ecuador.  相似文献   

14.
We present a first comparison of patterns of alpha and beta diversity of ferns, mosses, liverworts and macrolichens in neotropical montane rainforests, and explore the question whether specific taxa may be used as surrogates for others. In three localities in southern Ecuador, we surveyed terrestrial and epiphytic species assemblages in ridge and slope forests in 28 plots of 400 m2 each. The epiphytic habitat was significantly richer in ferns, liverworts, and macrolichens than the terrestrial habitat; mosses, however, were primarily terrestrial. Alpha diversity of ferns and of liverworts was congruent in both habitats. Mosses were similar to ferns and liverworts only in the epiphytic habitat. Macrolichens did not share patterns of alpha diversity with any other group. Beta diversity of ferns, mosses and liverworts (lichens excluded due to low species richness) was similar in the terrestrial habitat, but not in the epiphytic habitat. Our results demonstrate that patterns of alpha diversity of the studied taxa cannot be used to predict patterns of beta diversity. Moreover, diversity patterns observed in epiphytes are different from terrestrial plants. We noted a general coincidence in species patterns of liverworts and ferns. Diversity patterns of macrolichens, in contrast, were completely independent from any other taxonomic group studied.  相似文献   

15.
The epiphytic Rhipsalis riocampanensis from the upper montane rain forest of the Podocarpus National Park is described as a new species. A large columnar cactus previously known from N Peru, Browningia microsperma. is here recorded from the Loja province in southern Ecuador. It is the first time Browningia has been reported from Ecuador. Espostoa lanata ssp. roseiflora is described as a new subspecies based on a population in the Catamayo valley. It is suggested that Armatocereus rupicola is an older name for Armatocereus brevispinus.  相似文献   

16.
Glow-worms are bioluminescent fly larvae (Order Diptera, genus Arachnocampa) found only in Australia and New Zealand. Their core habitat is rainforest gullies and wet caves. Eight species are present in Australia; five of them have been recently described. The geographic distribution of species in Australia encompasses the montane regions of the eastern Australian coastline from the Wet Tropics region of northern Queensland to the cool temperate and montane rainforests of southern Australia and Tasmania. Phylogenetic trees based upon partial sequences of the mitochondrial genes cytochrome oxidase II and 16S mtDNA show that populations tend to be clustered into allopatric geographic groups showing overall concordance with the known species distributions. The deepest division is between the cool-adapted southern subgenus, Lucifera, and the more widespread subgenus, Campara. Lucifera comprises the sister groups, A. tasmaniensis, from Tasmania and the newly described species, A. buffaloensis, found in a high-altitude cave at Mt Buffalo in the Australian Alps in Victoria. The remaining Australian glow-worms in subgenus Campara are distributed in a swathe of geographic clusters that extend from the Wet Tropics in northern Queensland to the temperate forests of southern Victoria. Samples from caves and rainforests within any one geographic location tended to cluster together within a clade. We suggest that the morphological differences between hypogean (cave) and epigean (surface) glow-worm larvae are facultative adaptations to local microclimatic conditions rather than due to the presence of cryptic species in caves.  相似文献   

17.
Three new species of Melastomataceae (Blakeeae) are described:Blakea subpanduriformis, Topobea adscendens, andT. bullata. All are climbers endemic to the montane forests of the eastern slopes of the Andes in southern Ecuador. In this region, 35% of the Ecuadorian species and 41% of the endemic Ecuadorian species of Melastomataceae occur. The discovery of these three new endemic species underlines the diversity of Melastomataceae occurring on the slopes of the Andes in southeastern Ecuador.  相似文献   

18.
Species composition, physiognomy and plant diversity of the less known tropical montane forests in southern Yunnan were studied based on the data from 15 sampling plots in three sites. These forests are mainly dominated by the families Theaceae, Fagaceae, Lauraceae and Euphorbiaceae in floristic composition, and dominated by evergreen phanerophytes with mesophyllous leaves. These forests are similar to lower montane rain forests in equatorial southeastern Asia in floristic composition and altitudinal distributions, but differ in physiognomy by having few epiphytes, but more lianas and more plants with compound leaves. These differences could be due to strongly seasonal climate and so-called mass elevation effect in southern Yunnan. They also differ from the tropical seasonal rain forests at lower altitudes in southern Yunnan by having conspicuously lower species richness, few epiphytes, fewer mega-mesophanerophytes, more abundant micro-nanophanerophytes and hemicryptophytes and more plants with microphyllous leaves. It is suggested that these forests could be termed tropical montane evergreen broad-leaved forests, and be a vegetation type from the northern margin of mainland southeastern Asia controlled by a strongly seasonal climate.  相似文献   

19.
西双版纳热带雨林与海南热带雨林的比较研究   总被引:25,自引:2,他引:23  
西双版纳的热带雨林与海南低地热带雨林和热带季雨林有基本一致的植物区系组成,群落中优势科无论在种数百分比还是重要值排名上均较接近,显然属于同样性质的植物区系。在生态特征上,西双版纳热带雨林群落高大,分层不明显,B层为林冠层,散生巨树常见,在生活型谱上以高位芽植物占绝对优势,大、中高位芽植物相对较多,落叶树种比例小;以中叶、纸质,全缘和复叶比例较高为特征,具有最接近海南低地湿润雨林的群落垂直结构和生态外貌,其雨林特点虽不如湿润雨林浓厚,但明显强于海南的热带常绿季雨林和山地雨林,海南常绿季雨林群落高度明显较矮,小叶比例通常较高,革质叶比例亦较高,群落具遥明显的旱生特点,海南的山地雨林群落高度较矮,A层连续,成为林冠,无散生巨树,分层明显,在生活型谱上大高位芽植物比例减少,附生植物丰富,并具有相当比例的地面芽植物;叶级虽以中叶占优势,但通常革质,非全缘和单叶比例较高,明显由于热量不足的影响而带有亚热带森林特色,在物种多样性上,西双版纳热带雨林的乔木物种多样性指数似乎与海南的低地热带雨林相当,低于海南的山地雨林群落,海南的热带雨林群落种类丰富度不同人研究的结果差异较大,如果这些用于比较的数据可靠和具有可比性的话,西双版纳热带雨林的物种多样性要比海南的山地雨林低。  相似文献   

20.
Pentaplaris davidsmithii from Peru and Bolivia andP. huaoranica from Ecuador are described and compared to the only other species previously known in the genus,P. doroteae from Costa Rica. Morphological and palynological characters support the inclusion ofPentaplaris in core Malvales while suggesting that the original assumption that the genus belonged in Tiliaceae-Brownlowieae cannot be maintained.Pentaplaris, which comprises three isolated and evidently rare species, probably belongs to the malvoid-bombacoid alliance, but its position within this clade ramains unresolved.  相似文献   

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