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1.
Many environmental factors may influence the activity of scorpions in arid ecosystems. In this study, we examined the effects of such factors on scorpion activity at a mature and a secondary forest site in the Chancaní Reserve (Arid Chaco ecoregion in Córdoba, Argentina). Scorpions were collected using pitfall traps, and their nocturnal activity was observed by means of UV light during 14 nights. Temperature, air humidity, atmospheric pressure, and wind velocity were measured, and the percentage of visible moon was estimated. A total of 440 scorpions, representing seven species belonging to two families (Bothriuridae and Buthidae), were observed in the study area. Brachistosternus ferrugineus was the species most commonly observed using both methods. Mature and secondary forest shared slightly more than 50% of species. Surface activity of scorpions observed with the two methods differed significantly between the two areas. Surface activity of all scorpions and of B. ferrugineus were negatively related to the phase of the moon and positively related to air temperature. Physical factors thus have important effects on scorpion activity.  相似文献   

2.
Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species. Here, we focus on western North American Anodonta, one of only three genera known to exist in this broad landscape and which contains three highly divergent lineages. We describe phylogeographical subdivision in the most widespread and diverse of these lineages, which includes Anodonta californiensis and Anodonta nuttalliana and occurs from Canada to Mexico. Using mitochondrial and nuclear data, we found that genetic structuring within this clade is inconsistent with morphologically based species designations, but instead follows patterns of vicariance among major hydrogeologic basins. Furthermore, there was a strong tendency for population diversity within drainage systems to increase downstream, implying greater habitat or host fish availability in this direction. Microsatellite results indicated that sampling locations were all genetically distinct, even at short distances. Many of our sample populations showed evidence of a recent demographic bottleneck, although this effect seemed to be very local and not drainage or basin‐specific. This study provides a foundation for the establishment of appropriate management units and future research on adaptive differentiation and host fish relationships.  相似文献   

3.
The northeast of the Qinghai-Tibet Plateau, from the Hoh Xil Basin to the Hexi Corridor Basin, demonstrates a basin-ridge geomorphy that is the result of the long-term uplift of the Qinghai-Tibet Plateau. The geological evolution of the Qinghai-Tibet Plateau is recorded in its associated basins. From the Cenozoic sedimentary filling pattern in the Hoh Xil, Qaidam and Jiuquan Basins, we find that the evolution of these basins is similar: they began as strike-slip basins, evolved into foreland basins, and then to intermontane basins. Foreland basins are the direct result of orogenic activity in the northeast of Qinghai-Tibet Plateau, and can be documented to have formed over the following time periods: 49-23 Ma for the Hoh Xil foreland basin, 46-2.45 Ma for the Qaidam foreland basin, and 29.5-0 Ma for the Jiuquan foreland basin. This northward migration in the timing of foreland basin development suggests that the northeastern part of Tibet grew at least in part by accretion of Cenozoic sedimentary basins to its northern margin.  相似文献   

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Ethnoprimatology is an important and growing discipline, studying the diverse relationships between humans and primates. However there is a danger that too great a focus on primates as important to humans may obscure the importance of other animal groups to local people. The Waorani of Amazonian Ecuador were described by Sponsel [Sponsel (1997) New World Primates: Ecology, evolution and behavior. New York: Aldine de Gruyter. p 143–165] as the “natural place” for ethnoprimatology, because of their close relationship to primates, including primates forming a substantial part of their diet. Therefore they are an ideal group in which to examine contemporary perceptions of primates in comparison to other types of animal. We examine how Waorani living in Yasuní National Park name and categorize primates and other common mammals. Although there is some evidence that the Waorani consider primates a unique group, the non‐primate kinkajou and olingo are also included as part of the group “monkeys,” and no evidence was found that primates were more important than other mammals to Waorani culture. Instead, a small number of key species, in particular the woolly monkey (Lagothrix poeppigii) and white‐lipped peccary (Tayassu pecari), were found to be both important in the diet and highly culturally salient. These results have implications for both ethnoprimatologists and those working with local communities towards broader conservation goals. Firstly, researchers should ensure that they and local communities are referring to the same animals when they use broad terms such as “monkey,” and secondly the results caution ethnoprimatologists against imposing western taxonomic groups on indigenous peoples, rather than allowing them to define themselves which species are important. Am. J. Primatol. 75:1117–1128, 2013. © 2013 The Authors. American Journal of Primatology Published by Wiley Periodicals, Inc.  相似文献   

6.
Eocene and Oligocene chitons (Polyplacophora) from the Paris Basin of N France are described along with comparative material from the Hampshire Basin of the UK. The assemblages include eight species, five of which are new: Ischnochiton fehsei sp. nov., Stenoplax monila sp. nov., Chaetopleura gaasi sp. nov., C. abbessi sp. nov. and Tonicella lira sp. nov. Other taxa in the assemblages are Leptochiton cf. algesirensis, I. vectensis and S. anglica.  相似文献   

7.
Abstract. The aim of this quantitative biogeographical analysis is to identify the existence of specific groups of pteridophytes with significantly similar distribution patterns (chorotypes) in the Iberian Peninsula, as well as to infer the environmental factors that may explain such groupings. We have applied a classification method to the pteridophyte species and have then tested the significance of the resulting groups. This allows the distinction of groups of species that occur together more frequently than expected at random from those which are just a product of the cluster analysis. The majority of the 113 pteridophyte species in the Iberian Peninsula are not distributed independently from each other, but eighteen chorotypes exist that are common to various species and three chorotypes that consist of one species each. Five species are distributed independently of the other species, and so their distribution areas overlap and segregate from the others at random. With the aim of finding a relation between the chorotypes identified and the processes that determine them, we investigated the possible incidence of certain environmental factors on the chorotype distributions by means of logistic regression. Factors that appear most frequently as possible causes of the distribution of the chorotypes are the water availability, climatic stress, availability of environmental energy, and disturbances caused by floods. Resumen . El objetivo de este análisis biogeográfico cuantitativo es identificar la posible existencia de grupos de especies de pteridófitos con patrones de distribución significantivamente similares (corotipos) en la Peninsula Ibérica, así como analizar los factores ambientales que explican tales grupos. Hemos aplicado un método de clasificatión biogeográfica de especies y después hemos comprobado la significación de los grupos resultantes. Esto nos ha permitido distinguir los grupos de especies que se asocian con más frecuencia de lo esperado por azar de aquellos grupos que se deben únicamente al análisis de agrupación. La mayoría de las 113 especies de pteridófitos en la Península Ibérica no se distribuyen independientemente unas de otras, sino que existen 18 corotipos que son comunes a varias especies y tres que están formados por una sola especie. Cinco especies se distribuyen independientemente de las restantes, y por tanto, sus áreas de distribución se solapan y se segregan con las demás al azar. Con objeto de encontrar una relación entre los corotipos identificados en el presente trabajo y los procesos que los determinan, investigamos por medio de regresiones logísticas la posible incidencia de ciertos factores ambientales sobre las distribuciones de los corotipos. Los factores que han aparecido más frecuentemente como posibles causas de las distribuciones de los corotipos son la disponibilidad de agua, el estrés climático, la energía ambiental disponible y los disturbios causados por las inundaciones.  相似文献   

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In tropical forests, much of the plant diversity is due to a large number of congeneric taxa. It is unclear what ecological processes are responsible for the number and composition of co‐occurring species in these forests. Here, we present strong evidence that microhabitat heterogeneity may contribute to the coexistence of many different Inga species in just 100 ha. We examined their patterns of abundance and diversity in 75 transects related to the edaphic variables: soil water content, pH and soil texture at three different microtopographical units (ridges, slopes and valleys). We used two different approaches: Inga community level analyses and individual‐species analyses. Multivariate analyses, controlled for spatial autocorrelation, demonstrated that species show a distributional gradient mainly related to soil water content and to a lesser degree pH. Individual‐species analyses determined that obligate microhabitat restriction is uncommon: only 2 of 37 species analyzed were restricted to a single microhabitat. Habitat association analyses, however, identified a number of species characteristic of the ridge, slope and valley microhabitats. We conclude that the environmental setting plays an important role in the Inga community assembly but is not sufficient to explain the coexistence of 37 sympatric species at a single site.  相似文献   

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Aim We conducted a range‐wide phylogeographic study of a common Australian freshwater fish, the golden perch (Macquaria ambigua), to investigate the relationship between environmental processes and evolutionary history in drainage basins. Location Inland [Lake Eyre (LEB), Murray–Darling (MDB) and Bulloo (BULL)] and coastal basins [Fitzroy (FITZ)] of eastern Australia. Methods A total of 590 samples were collected from across the entire species’ distribution and a section of the mitochondrial DNA control region was sequenced. In order to reconstruct the evolutionary history of M. ambigua a comprehensive suite of phylogeographic analyses was conducted, including nested clade phylogeographic analysis, mismatch analysis and isolation‐with‐migration model simulations. Results Three major lineages corresponding to the major drainage basins, FITZ, MDB and LEB/BULL, were identified (ΦST = 0.92). Lineages from the coastal basin (FITZ) were highly divergent from those of the inland basins (up to 6%). Levels of genetic diversity in the inland basins were relatively low and our analyses indicate that these populations experienced both demographic and range expansions during the Pleistocene. Main conclusions Investigation of the range‐wide phylogeography of M. ambigua has revealed new insights into the biogeography of the Australian arid zone, particularly with regard to evolutionary events chronologically associated with cyclical moist and dry conditions. We propose that M. ambigua originated on the east coast (FITZ) and crossed a major geographic barrier, the Great Dividing Range (GDR), to colonize the inland basins (MDB, LEB and BULL). We infer a series of demographic and range expansion events for M. ambigua consistent with a scenario of moister Pleistocene conditions and increased connectivity of freshwater environments, both within and among drainage basins. Major lineages then diversified following isolation of freshwater environments under increasingly arid climate conditions. We suggest that management priorities for M. ambigua should include the resolution of taxonomic uncertainties and the maintenance of genetic diversity of both stocked populations in the MDB and native populations of the LEB that may be at risk of further isolation and reduced gene flow due to increased aridification under future climate change scenarios.  相似文献   

13.
Pontian deposits of the Zagorje Basin constitute a coarsening-upward succession, which reflects the infilling style of this Pannonian sub-basin, i.e. the progradation of clastic systems into the brackish lake. Six facies differentiated correspond to lake floor, channelled slope, distal and proximal pro-delta, distal and proximal mouth bars, and lagoon/bay to swamp and alluvial environments. The deposition in the mouth-bar area was dominated by frictional forces. The upper-stage plane-bed sands are the main mouth-bar facies, which is uncommon in the geological record. The main factors for the origin of such bars include an abundant sand supply by the high-energy fluvial system(s), low-energy of the receiving basin and shallow depositional depth. Prolonged, catastrophic floods generated sustained hyperpycnal flows, which bypassed the mouth-bar area and fed the slope/pro-delta. The high ratio between sediment supply and subsidence rate resulted in a fast moving progradational wave, which involved the entire SW Pannonian Basin, including the Zagorje Basin.  相似文献   

14.
Behuria comosa Tavares, Baumgratz & Goldenberg is a new species from Minas Gerais and Espírito Santo, Brazil. It can be recognized by the branch nodes, sinuses of the leaf margins and domatia comose, leaves and inflorescence axes frequently three‐whorled, flowers five(–six)‐merous, calyx lobes broadly triangular and with the apex laterally flattened, and petals glabrous, thickly apiculate. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 489–492.  相似文献   

15.
从微体化石群看我国沿海早第三纪含油盆地的差异   总被引:3,自引:0,他引:3  
对我国沿海3个含油盆地-珠江口、北部湾和渤海湾盆地下第三系湖相生油岩中的微体化石群进行比较分析。3个盆地中以渤海湾盆地下第三系湖相化石群最为丰富,数量多,分异度高,而且化石群以地方性属种比例高、咸水类型多,存在“海源陆生生物化石”为特征;北部湾盆地,在涠洲组和流沙港组发现较多的介形类化石及个别腹足类和轮藻化石;而珠江口下经三系湖相地层中,微体化石罕见,只在个别层位发现贝壳碎片。据化石群特征,推测渤海湾盆地早第三纪是封闭型的咸水湖泊,而且部分沉积时期,可能是以Cl^-和Na^ 为主的咸水湖泊;珠江口盆地早第三纪是湖水矿化度低、硬度、pH值也低的淡水湖泊;而北部湾盆地早第三纪可能仍属淡水湖泊,但有一定的矿化度。  相似文献   

16.
A new species of Profundulus, Profundulus portillorum, from the Honduran central highlands is described. Profundulus portillorum belongs to the Profundulus labialis species group and is distinct from the Profundulus punctatus species group in that it lacks a humeral spot and less than half of the caudal fin is scaled. Within the P. labialis species group, P. portillorum has a more slender body, smaller eye, fewer anal rays, caudal rays and lateral‐line scales than other species. Forty‐one specimens were collected around emergent vegetation in the margins of two small (2–5 m in width, 20–40 cm in depth), high‐elevation (1300 m) tributaries of the Río Calam within the Río Ulúa drainage. These specimens represent the easternmost collection of any Profundulus and the first collection of any member of the P. labialis species group from Honduras.  相似文献   

17.
Chimpanzee tool behaviours vary dramatically in their complexity and extent of geographical distribution. The use of tool sets with specific design features to gather termites extends across a large portion of central Africa. Detailed examination of the composition and uniformity of such complex tool tasks has the potential to advance our understanding of the cognitive capabilities of tool users and processes underlying the maintenance of technological skills. In this study, we examined variation in chimpanzee tool use in termite gathering from video-recorded sequences that were scored to the level of functionally distinct behavioural elements. Overall, we found a high degree of similarity in tool-using techniques exhibited by individuals in this population. The number of elements in each individual's repertoire often exceeded that necessary to accomplish the task, with consistent differences in repertoire sizes between age classes. Adults and subadults had the largest repertoires and more consistently exhibited element strings than younger individuals. Larger repertoires were typically associated with incorporation of rare variants, some of which indicate flexibility and intelligence. These tool using apes aid us in understanding the evolution of technology, including that of our human ancestors, which showed a high degree of uniformity over large spatial scales.  相似文献   

18.
以三工河流域为例,讨论了植被动态及其地貌、水资源利用、河流廊道和排碱渠等景观要素的变化对植被产生的影响.结果表明,随着景观格局的变化,流域内的植丛高度、盖度及生物量均表现出较大变异性.以河流廊道为核心,通常荒漠绿洲景观格局呈带状分布,且由内向外随水热条件的改变,植被类型由乔灌木林依次向灌丛草甸、盐化草甸、荒漠化草甸和荒漠层次结构过渡.人类活动影响强烈的景观要素,其斑块多样性、破碎度、分离度和斑块密度等指数值较高,而人类活动影响较小的,其优势度和均匀度较高.各景观要素的稳定性不同,其大小顺序为:荒漠>沙砾石地>城镇用地>水体>农田>牧草地>菜地>林地>居民点>盐碱地>荒草地>水浇地>果园.梭梭群落的净生长量高峰值出现在8月,而博乐蒿、琵琶柴群落的净生长量高峰值出现时间各年度不同.博乐蒿群落与海拔相关系数最大,而琵琶柴群落则与土壤水含量、地下水位关系密切,梭梭群落与4~9月降雨量相关系数最大.  相似文献   

19.
《Palaeoworld》2014,23(3-4):285-293
The well-preserved theropod track Weiyuanpus zigongensis, recently assigned to Eubrontes zigongensis, was not described in exhaustive detail at the time of its original discovery in 2007. Among the morphological details not described was an antero-medially directed hallux seen in five of the six tracks that make up the type trackway. Hallux traces are only rarely reported in large Lower Jurassic theropod tracks such as Eubrontes and Gigandipus, and their presence or absence may be the result of one or both of two factors: track depth and/or differences in hallux configuration in the trackmakers. Here we argue that E. zigongensis is one of the best preserved examples of a eubrontid track, which can be morphologically distinguished from other Eubrontes ichnospecies by the presence of well-defined hallux traces.  相似文献   

20.
We explored the small‐scale plant species mobility in a subhumid native grassland subjected to grazing by cattle in south‐western Uruguay. We established four permanent plots of 40 × 40 cm, divided in 16 × 16 cells. In each cell, the presence of species was seasonally recorded for 2 years and annually recorded for 4 years. By nesting the cells, we studied the mobility at different scales, from 6.25 cm2 to 400 cm2. At each scale we measured species richness, cumulative richness and the turnover rates of the dominant species. We found that the cumulative species richness was an increasing power function, with higher accumulation rates with smaller spatial scale. Although species richness showed seasonal fluctuations, the mean species richness was constant during the study period. We detected significant spatio‐temporal variability in mobility patterns among species. Certain species showed a high capacity to colonize new sites, whereas other species rotate among sites that they previously occupied. Grazed communities in Uruguayan Campos are structured as a dense matrix of perennials grasses and forbs, where vegetative propagation is the main form of growth of the species. The small‐scale dynamics and the high variability in the mobility characteristics could be linked with the diversity of growth forms and spatial strategies of the species in this community. We believe that a high degree of small‐scale spatial dynamics contribute to explain the species coexistence and the apparent stability of communities at local scales.  相似文献   

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