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1.
Trophic relations among introduced species may induce highly variable and complex effects in communities and ecosystems. However, studies that identify the potential impacts for invaded systems and illuminate mechanisms of coexistence with native species are scarce. Here, we examined trophic relations between two introduced fishes in streams of NW Patagonia, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta). These species originate from different regions of the Northern Hemisphere but they now coexist as invading species over the world. We used gastric contents and stable isotopes analysis to compare the diets of two size‐classes of these two invaders in three localities of southern Chile. Both species displayed similar ontogenic diet shifts with smaller trout consuming mostly invertebrates and larger trout being more piscivorous and epibenthic feeders. However, piscivory was more prevalent in brown trout than in rainbow trout and highest at the site with the greatest density of native fishes suggesting that the availability of native fishes as trout prey may limit the occurrence of trout piscivory. We found an elevated dietary overlap between the two trout species at larger sizes while at smaller size a higher intraspecific dietary overlap occurred suggesting a potential interference competition among the two fish invaders especially at larger sizes. Our results highlight that the impacts of invading species on non‐native fishes are context specific (i.e. species and ontogenic stages) and thus, difficult to generalize. 相似文献
2.
We record here the introduction of the African catfish Clarias gariepinus into the Guaraguaçu River basin in Paraná State, Brazil, an area with an extremely rich endemic fish fauna, including many catfishes. C. gariepinus was introduced as escapees from ponds built for recreational angling. These catfishes are very large and hard predators, thus posing serious potential for impact on the native fish fauna. The impact of C. gariepinus needs study with emphasis on finding means for controlling its spread. 相似文献
3.
在光学显微镜和扫描电镜下,对东亚地区帚菊木族及其南美相关类群共12属31个种的叶表皮进行了观察.研究发现气孔器普遍存在于叶的下表皮,少数种的上表皮也有分布,气孔器主要为星型和无规则型两种类型.叶表皮细胞为多边形和不规则形,垂周壁平直弓形、浅波状或波浪状.气孔器表面观为椭圆形和近圆形,气孔外拱盖内缘近平滑至浅波状,其中 Macroclinidium 较为特殊,具有双层气孔外拱盖.叶表面通常光滑无蜡质或角质,部分种叶表面具薄片状或层状蜡质.研究表明,叶表皮特征在种间一致性较高,但在属间,特别是属群和亚族间存在一定差异. 相似文献
4.
China’s current invasive alien plant species were analyzed with regard to their floristic status, biological attributes and
invasion status elsewhere. Most of the 270 species identified were annuals, followed by perennial herbs. Woody perennials
made only about 10% of the species. The invasives were comprised of 59 families, the largest being Asteraceae, Poaceae, and
Brassicaceae. The genera with most invasive species were Amaranthus, Ipomoea, and Solanum. Most of the species originated from the New World, notably from South America. About one-third of the species were serious
invaders of natural habitats in countries other than China. The proportion of invasive alien plants in province floras ranged
from 0.5 to 3.8%, absolute numbers from nine to 117 species per province. Density of invasive species was correlated positively
with native species density at provincial scale. The results demonstrate that in China invasive plants are present throughout
the country, with a particularly high species richness in the Southeast. The ecological diversity of invasive plants suggests
wide ranging impacts which need to be assessed. 相似文献
5.
1. Data from the literature were used to document colonization patterns by introduced freshwater fishes in 125 drainages across temperate North America. We analysed this data set to quantify susceptibility to invasion, success of the invaders and changes in species richness.
2. Drainages with a high number of impoundments, large basin area and low native species diversity had the greatest number of introduced species. Those drainages containing few native fishes exhibited great variation in the number of invaders, while waters with a rich native fauna contained few introduced species. However, this pattern did not differ significantly from random simulations because the pool of potential invaders is greater for drainages with low species richness.
3. In most drainages, there were more introduced than imperilled or extirpated species, suggesting that invaders tend to increase overall species richness.
4. These patterns suggest that North American fish communities are not saturated with species, but instead, are capable of supporting higher levels of diversity if the pool of potential colonists and the rate of colonization from that pool is increased. 相似文献
2. Drainages with a high number of impoundments, large basin area and low native species diversity had the greatest number of introduced species. Those drainages containing few native fishes exhibited great variation in the number of invaders, while waters with a rich native fauna contained few introduced species. However, this pattern did not differ significantly from random simulations because the pool of potential invaders is greater for drainages with low species richness.
3. In most drainages, there were more introduced than imperilled or extirpated species, suggesting that invaders tend to increase overall species richness.
4. These patterns suggest that North American fish communities are not saturated with species, but instead, are capable of supporting higher levels of diversity if the pool of potential colonists and the rate of colonization from that pool is increased. 相似文献
6.
7.
Stephania Loureiro is a large genus within Menispermaceae, with approximately 60 extant species naturally distributed in tropical to subtropical areas in Asia and Africa, and a few in Oceania. This genus possesses highly characteristic endocarps that facilitate identification of extant and fossil specimens. Here, we report some well-preserved fossil fruits of Stephania from North America and East Asia. The specimens indicate the endocarps were bony or woody with an obovate to obovate-rotund outline and a horseshoe-shaped locule. The endocarp length varies from 4.7 to 8.3 mm, and width from 3.7 to 7.0 mm. The endocarp has a clear foramen in the central area and is surrounded by a keel with ribs running along the dorsal surface. Only one lateral crest develops on each side of the endocarp. Two new species are recognized: Stephania wilfii Han & Manchester sp. nov. from the Paleocene to Eocene of Wyoming (USA), and Stephania jacquesii Han & Manchester sp. nov. disjunct between the late Eocene of Oregon (USA) and the late Oligocene of Guangxi Province (China). In addition, on the basis of more detailed morphological comparative analyses, we transfer the fossils formerly treated as Diploclisia auriformis (Hollick) Manchester from the early Eocene of London Clay, and the middle Eocene of Alaska and Oregon to Stephania auriformis (Hollick) Han & Manchester comb. nov. These fossil materials indicate a broader biogeographic distribution for the ancestors of extant Stephania lineages. This finding enhances our knowledge of the taxonomic and morphological diversity of Stephania and provides new evidence concerning its phytogeographic history. 相似文献
8.
Watana SAKCHOOWONG Shûhei NOMURA Kazuo OGATA Jariya CHANPAISAENG 《Entomological Science》2008,11(3):301-313
Pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) are cosmopolitan, species‐rich, and yet poorly studied, particularly in the tropics. We sampled beetles in three types of primary forest and two types of disturbed forest habitats in eastern Thailand to assess the utility of pselaphine beetles as bioindicators of forest disturbance. We simultaneously measured leaf litter mass, soil moisture, soil acidity and canopy cover at each site to infer which environmental factors affect pselaphine beetle diversity and abundance. At each site, pselaphine beetles were extracted from ten 1 m2 samples of leaf litter and soil with Tullgren funnels. We sampled 1867 adult beetles representing six supertribes, 51 genera and 114 morphospecies; 7% of the genera and 92% of the species were undescribed. Forest types differed significantly in species richness, abundance, diversity and evenness. Primary forest had greater numbers of species and individuals, and higher diversity indices (H′). Teak plantation and secondary forest had substantially fewer individuals and species of pselaphine beetles. Species composition differed between primary and degraded forests. Canopy cover, soil moisture, and leaf litter mass positively correlated with beetle species richness and abundance. Leaf litter mass and soil moisture were the two most important factors affecting the diversity of pselaphine beetle assemblages. Among the 114 morphospecies collected, 43 morphospecies were specific to two or three habitats and 64 morphospecies were found only in a single habitat. Thus pselaphine beetles appear to have rather narrow habitat requirements and their presence/absence was correlated with environmental differences. These traits make pselaphine beetles a suitable bioindicator taxon for assessing forest litter diversity and monitoring habitat change. 相似文献
9.
Synopsis We report the finding of an established population of exotic Chinook salmon spawning in headwaters of the Santa Cruz River
system (Argentina), the first for this species in an Atlantic basin of South America. Spawning takes place in the Caterina
River, a small tributary of Lake Argentino, located 488.5 km from the ocean. Anadromy was verified by correspondence of N
and C stable isotope ratios with those of fish captured by bottom-trawlers in the ocean and those of anadromous rainbow trout
from the same river basin. The scale patterns of most fish examined were consistent with a stream-type life cycle (i.e., seaward
migration by juveniles after a full year in fresh water). Two potential origins were identified for this population: in situ
introductions of fish imported directly from the USA in the early 20th century or fish from two ranching experiments conducted
in southern Chile during the 1980s. In the latter case, colonization would have proceeded through the Strait of Magellan,
helped by prevailing eastward currents. 相似文献
10.
东亚与北美当归属花粉形态的比较研究 总被引:5,自引:2,他引:5
对东亚与北美当归属(AngelicaL.)72种植物的花粉形态特征进行了观察,表明当归属的花粉为一多类型的类群,包含伞形科全部6种花粉类型,说明该属既是一个古老的属,同时又是在发展中不断演化的属。东亚和北美的共有种表明两地区的当归属十分近缘。从两地区存在着古老的姊妹群推断它们共同起源于白垩纪到老第三纪。中国的四川和北美的西北部同为当归属的起源和演化中心。花粉特征还表明当归属的近缘属山芹属(OstericumMaxim.)为一自然的分类群 相似文献
11.
Müllerian mimetic systems have uncovered some of the dynamic processes by which natural selection can drive the radiation of convergent and divergent phenotypes. We examined evolution involving Müllerian mimicry in bumble bees by documenting the distribution and evolution of colour patterns amongst three colour‐polymorphic lineages –Bombus trifasciatus Smith, Bombus haemorrhoidalis Smith, and Bombus breviceps Smith – that mimic each other across ~14 colour groups in South‐East Asia. Using mitochondrial DNA sequence data, we estimated relationships within each lineage to infer the processes that gave rise to the colour diversity and develop hypotheses on species recognition. We expanded on our assessment of species delineation in the B. trifasciatus lineage using three nuclear gene fragments and morphometrics. Comparison of colour patterns amongst georeferenced specimens showed considerable variation in the degree and geographical range of mimicry amongst mimicry groups. Phylogenetic estimates show high rates of colour pattern evolution, with colour variation often exceeding variation within the fast‐evolving mitochondrial genes. The molecular data, and to some degree the morphometric data, support unique histories for several taxa recognized previously within the B. trifasciatus lineage, which may include several species. Early vicariant events within the B. trifasciatus lineage are likely to have occurred ~2.2 Mya in the mountains of south‐west China. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 805–826. 相似文献
12.
A new species of Veturius (Veturius) Kaup from southern Colombia, Putumayo, lowland forests, is described and illustrated. V. paya n. sp. belongs to the South American “cephalotes” species group and is sister species of V. cephalotes (Le Peletier & Serville, 1825). Both species are distinguished by few characters of the head and thorax. They seem to be allopatric close to the western distributional limits of V. cephalotes. The endemism of V. paya n. sp. corresponds to a geographic vicariance in the axis of the Amazon Basin. An overview is given on the phylogeny and the chorology of the completed “cephalotes” species group. 相似文献
13.
Luis Alberto Pereira 《Studies on Neotropical Fauna and Environment》2018,53(2):91-106
A new miniature species of geophilomorph centipede, Ityphilus grismadoi sp. nov. (Chilopoda: Geophilomorpha: Ballophilidae) is fully described and illustrated on the basis of specimens collected in Yasuní Scientific Station and Jatun Sacha Biological Station, both located in the Ecuadorian Amazon. The new species is characterized by having the internal edge of the forcipular tarsungulum completely smooth, this trait being shared by six other Neotropical members of the genus Ityphilus Cook, 1899; and another species (I. cifuentesi Cupul Magaña, 2014) from the transition area between the Neotropical and Nearctic regions. Ityphilus grismadoi sp. nov. is distinguished from these seven species by the low number of leg-bearing segments (37, 39), and the very small body size (7–9 mm in length) and for a confident identification it is compared in detail with those having a roughly similar range of leg-bearing segments. This is the first record of the genus Ityphilus from Ecuador and the second report of a ballophilid centipede from the country (the other represented by Zygethmus pantenus Chamberlin, 1957). A key to the Neotropical members of Ityphilus with forcipular tarsungulum smooth (including I. cifuentesi) is also given.
http://zoobank.org/urn:lsid:zoobank.org:pub:32F77890-9DC5-47AC-A794-29C4437C3B93http://zoobank.org/urn:lsid:zoobank.org:act:3EB64970-F159-4C6E-B9FF-AF9D09128553 相似文献
14.
Jon Paul Rodríguez 《Biodiversity and Conservation》2001,10(11):1983-1996
Prior studies on the latitudinal extent and ecological impact of exotic plant species suggest that areas of high diversity, such as the Neotropics, may be relatively 'resistant' to invasions. To explore the generality of this assertion and assess the impact of alien species on continental tropical faunas, I compiled data for threatened Neotropical animals from the red data books of Bolivia, Brazil, Minas Gerais (a Brazilian state), Peru, and Venezuela. A total of 378 species (including both vertebrates and invertebrates) were considered. For each taxon, I recorded whether it is threatened by habitat conversion, overexploitation, and/or exotic species. As suggested by other researchers, exotic species introductions appear to be relatively unimportant in South America, threatening only 6% of animal taxa. However, many South American animals are themselves either recent invaders or survivors of the Great American Biotic Interchange (GABI) which began during the Pliocene. Here, I hypothesize that the GABI may have acted as an 'extinction filter', leaving faunal groups of mostly South American origin relatively more threatened by the current wave of exotic invaders than those with prominent North American representation. The data support this prediction. For taxa whose current diversity patterns were not strongly influenced by the GABI, exotic species are indeed an important threat. For example, alien invaders threaten 29% of continental fishes and 30% of amphibians, figures comparable to those recorded in temperate areas. As more information on these less-studied taxa becomes available, the magnitude of the threat posed by exotic species introductions will probably reveal itself to be large. Of critical importance is to assess the impact of invasions on biological realms that have only been recently exposed to alien taxa, such as the aquatic faunas of the numerous drainages that occur along the eastern and western slopes of the South American Andes. The results of these investigations provide predictions for similar research focussed on other continental tropical regions of the world. 相似文献
15.
作者在整理北美外来入侵植物中发现一些起源(或主要分布)于东亚植物的学名,在北美乃至欧洲使用非常混乱.本文特将有关重要类群整理出来,包括异名、原产地、北美的分布以及必要的讨论等. 相似文献
16.
Although there have been many studies of the ecology of primates in communities throughout the world, there have been few attempts to compare community ecology within and among continents. In this study the ecological characteristics of the sympatric primate species at eight localities—two from each of the major biogeographic areas inhabited by primates today—South America, Africa, Madagascar, and Asia—were compared using a multivariate technique (principal components analysis of the correlation matrix) to summarize the ten dimensional ecological niche space. The most striking clustering of species in ecological multivariate space is according to phylogeny with closely related species showing similar ecological features. Likewise, the ecological characteristics of individual communities are determined by phylogenetic groups present at each locality or biogeographic region. As a result, communities within any biogeographical region are more similar ecologically to one another than to communities from other continental areas. In several measures of ecological diversity among the species comprising each community, the neotropical communities show lower overall diversity than do communities from other continents. 相似文献
17.
Bocconia (10 species) and Macleaya (2 species) are two disjunct genera between South America and eastern Asia (EAS) in the Papaveraceae offering an opportunity to compare its biogeographic history with that of the well‐known disjunction between EAS and eastern North American (ENA). Our phylogenetic analyses of the chloroplast matK and rbcL gene sequences of Ranunculales including two species of Macleaya and six species of Bocconia supported the monophyly of Bocconia, Macleaya, and Chelidonioideae to which Bocconia and Macleaya belong. Nucleotide sequences of matK, rbcL, and nrDNA ITS supported the sister relationship of Bocconia and Macleaya. Biogeographic analyses of Chelidonioideae using S‐DIVA (statistical dispersal vicariance analysis) and DEC (dispersal extinction cladogenesis) methods inferred Eurasia as the most likely ancestral area of Bocconia and Macleaya and suggested no extinction events in either Bocconia or Macleaya. This agrees with the “Out‐of‐Asia” pattern of the EAS‐ENA disjunction. Molecular dating of Ranunculales with fossil‐based calibrations showed that Bocconia and Macleaya diverged in the late Eocene and early Oligocene, which is much earlier than most EAS‐ENA disjunct taxa. The disjunction may have formed via long distance dispersal or boreotropical connections via the North Atlantic and Bering land bridges. Both Bocconia and Macleaya diversified in the late mid‐Miocene, but Bocconia has apparently experienced a greater diversification probably aided by the evolution of the bird dispersal syndrome in fruit and seed after migration to South America. The greater diversification of Bocconia is also evidenced by the diverse leaf morphology and growth habit in response to colonization in various local habitats in South America. 相似文献
18.
Invasive geckos of the genus Hemidactylus (Gekkonidae) are spreading rapidly through urban environments in many tropical and subtropical parts of the world. The invaders have caused rapid declines in native gecko abundance in some areas, but their interactions with Australian native species remain unknown. In a small rural village near Darwin, we found that Hemidactylus frenatus is abundant around both lighted and unlighted buildings, but rarely found in surrounding bushland. It is sympatric with the larger Gehyra australis (Gekkonidae) in this disturbed site, and often forages on the same buildings, but is active mostly during the dry‐season (vs. wet‐season for G. australis) and is competitively subordinate to the larger native species. In laboratory encounters, H. frenatus fled from G. australis, and modified its refuge‐site use in the presence of the native lizard. In those same trials, the native gecko often attacked and rarely fled; and did not shift its refuge‐site selection. In field surveys, the two taxa frequently co‐occurred. However, substrate use of the invasive H. frenatus was modified by the presence of the native G. australis, consistent with competitive displacement. Our counts of H. frenatus were highest during the dry‐season, when G. australis (like most other small native reptiles) is relatively inactive. The invasive gecko thus appears to be exploiting a ‘vacant niche’ around buildings, rather than displacing the native gecko taxon. This outcome may reflect the size disparity between the native species and the invader; Hemidactylus frenatus may well have significant ecological impacts on smaller native lizards. 相似文献
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20.
Acantholycosa azarkinaesp. n. is described from the Maritime Province of Russia on the basis of both sexes. Acantholycosa norvegica (Thorell, 1872) is reported from the Maritime Province for the first time. A key and illustrations to all six species that occur in Far East Asia are provided. 相似文献