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1.
Understanding the factors that regulate geographical variation in species richness has been one of the fundamental questions in ecology for decades, but our knowledge of the cause of geographical variation in species richness remains poor. This is particularly true for herpetofaunas (including amphibians and reptiles). Here, using correlation and regression analyses, we examine the relationship of herpetofaunal species richness in 245 localities across China with 30 environmental factors, which include nearly all major environmental factors that are considered to explain broad-scale species richness gradients in such theories as ambient energy, water–energy dynamics, productivity, habitat heterogeneity, and climatic stability. We found that the species richness of amphibians and reptiles is moderately to strongly correlated with most of the environmental variables examined, and that the best fit models, which include explanatory variables of temperature, precipitation, net primary productivity, minimum elevation, and range in elevation, explain ca 70% the variance in species richness for both amphibians and reptiles after accounting for sample area. Although water and temperature are important explanatory variables to both amphibians and reptiles, water variables explain more variance in amphibian species richness than in reptile species richness whereas temperature variables explain more variance in reptile species richness than in amphibian species richness, which is consistent with different physiological requirements of the two groups of organisms. 相似文献
2.
《Journal for Nature Conservation》2014,22(4):337-341
Biodiversity conservation in forested landscapes outside protected areas is important to sustain populations of species with restricted ranges. However, such habitats face many anthropogenic threats, including logging, extraction of firewood and leaf-litter for mulch in plantations. In this study, we determined the effects of forest degradation on amphibians and reptiles in forests outside protected areas by measuring their species richness and community composition across a disturbance gradient from near pristine to highly degraded forests in Agumbe, Western Ghats, India. Twenty-one strip 15 m × 150 m transects were laid across the disturbance gradient and diurnal visual encounter surveys were conducted. Sampling was repeated three times per transect covering the dry, intermediate and wet seasons. Amphibian and reptile communities were affected by the decrease in canopy cover and leaf litter volume, respectively. Our results indicate that the collection of firewood and leaf-litter can severely affect amphibian and reptile populations. Structured conservation planning outside of protected areas is therefore imperative. 相似文献
3.
Urban areas are primary causes of species' range fragmentation and reduction. However, relatively few studies have attempted to describe the habitat variables influencing the diversity and conservation of amphibians and reptiles, particularly in Mediterranean Europe and in large metropolitan areas. We explored this broad conservation ecology problem by studying the richness and diversity patterns in relation to a suite of six independent habitat variables in Rome, one of the most ancient cities of the world. We considered all the green remnant areas ( n =62) of Rome, ranging 1 to >1000 ha in size, which are interspersed within a sea of urbanized matrix. A total of 10 amphibian and 15 reptile species were studied. Their presence/absence patterns were assessed and the effects of the various habitat variables on each species were predicted by a logistic regression model. A total of 1261 presence records (404 amphibians and 857 reptiles) were analysed. Fragment size and wood size within each fragment did correlate significantly with the species richness of both amphibians and reptiles, and there was a clear threshold effect after 50 ha of wooded surface. The presence of water bodies positively affected the species distribution. One amphibian and three reptiles inhabited exclusively fragments >50 ha. The distance from the centre did not affect fragment species richness. The presence of most species of both amphibians and reptiles was positively influenced by the irregular versus circular shape of the wooded area. The legal protection of a given area did not influence the observed patterns but the total number of sheltered species. Overall, our study suggests that, in order to maintain the current diversity and population viability, it is necessary, in addition to water bodies' maintenance, to (1) preserve the wooded landscapes over 50 ha; (2) promote irregularly shaped increases in the wood surface; (3) maintain ecotonal boundaries. 相似文献
4.
海拔梯度综合了温度、降水等气候因子,是影响物种多样性分布格局的重要环境因子,两栖动物多样性及其海拔分布格局一直是生物地理学和生态学研究的重要内容。为了全面掌握云南澜沧县两栖动物多样性现状及海拔分布格局,在调查并掌握澜沧县两栖动物多样性本底数据的基础上,根据地形地貌和生境的不同,在澜沧县99个10km×10km有效网格中按照分层抽样的方法选取45个网格,每个网格设置3-5条样线,于2016-2017年开展野外调查。调查共发现两栖动物1842只,隶属于2目9科30属60种,以树蛙科为主,占两栖动物物种总数的28.3%,其中云南纤树蛙(Gracixalus yunnanensis)为新种,清迈泽陆蛙(Fejervarya qingmaiensis)为中国新纪录种;调查到中国特有种有15种,三有保护动物有25种,受威胁物种有19种,其中极危物种1种,濒危物种4种,易危物种14种;澜沧县两栖动物在海拔600-2400m范围内均有分布,其中,在海拔1800-2000m之间的范围内调查到的两栖动物物种数目和多度均较高,其次是在海拔1600-1800m和1200-1400m范围内;本次调查记录到的两栖动物物种数是历史记录物种数的3倍,属数比历史记录多了1倍,铃蟾科为新记录科;丰富度较高的网格尤其是丰富度在20以上的网格均处于中高海拔,海拔相对较低和较高的网格丰富度相对较低;两栖动物多样性科、属、种的丰富度在海拔梯度上分布格局不太一致,种丰富度的海拔分布格局大体呈双峰型,是由包括平均降水量、平均温度和植被覆盖指数等环境因子的综合作用,各因子与物种丰富度相关性从大到小依次为平均降水量 > 平均海拔=平均温度 > 植被覆盖指数 > 水网密度指数 > 样线距离水域的平均距离 > 植被类型数量。研究摸清了澜沧县两栖动物的多样性状况,分析了两栖动物多样性海拔分布格局,为澜沧县生物多样性保护提供基础数据。 相似文献
5.
Amphibian and reptile communities of rainforest fragments: minimum patch size to support high richness and abundance 总被引:1,自引:0,他引:1
Information on animal communities inhabiting Neotropical fragmented landscapes is important for developing conservation strategies. The structure of amphibian and reptile communities in six tropical rainforest fragments (<20?ha) and two reference areas in continuous forest at Los Tuxtlas, Mexico was studied. A total of 3,481 individuals of 51 species of amphibians and reptiles were recorded across 12 bimonthly surveys during 2 years. Taxonomic composition was different between the smallest fragments and the reference areas. Six species were exclusive to large undisturbed forest and richness was significantly lower in the five smallest fragments (1.4–6.6?ha) compared with the largest patch, one or both of the reference areas. Amphibian abundance tended to be higher in large areas, while reptiles were more abundant in the five smallest fragments. Craugastor loki and Anolis uniformis were the dominant species in all sites, and particularly in the smaller fragments. Amphibian and reptile richness was positively related to larger patch sizes, deeper leaf litter, closed canopy cover, and higher relative humidity and negatively related to linear patch shape and high temperatures. Abundance of reptiles was positively associated to high temperatures, high density of woody debris, and closed canopy cover; it was negatively affected by linear patch shape, low humidity levels, and steeper slopes. While amphibian and reptile communities were strongly affected in vegetation fragments, these patches retained a considerable number of rainforest species. Fragments up to at least 17?ha have the potential for preserving communities with similar structure to those occurring in large tropical rainforests. 相似文献
6.
Due to the current environmental crisis, many animal species face extinction problems. Amphibian populations have been affected by this crisis. Our goal is to study amphibian species diversity in Chiapas, which has 7.6% of the endemic amphibians in Mexico and 53 protected areas. Only 58% of the protected areas have management plans or information on their resident amphibians. We aim to determine the extent of protection provided by the network of natural areas for the conservation of amphibian species in the state and to discuss the effectiveness of this protection. Therefore, we compiled a georeferenced database of 112 amphibian species in Chiapas to create each distribution model. In addition, we carried out representativeness, beta diversity, and species richness analyses. As a result, we obtained a high degree of representativeness for the records and species distribution models. However, we found a decrease in the richness of amphibians involving 20% of total species, 13% of endemics, 18% threatened according to NOM-059, and 31% threatened according to IUCN between 1800 and 2020 and 1980–2020. We also identified two biodiversity hotspots in the Sierra Madre de Chiapas and the Northern Highlands physiographic regions. Finally, based on potential distributions, we found more endemic and threatened species outside protected natural areas than inside them. Our results give a broader picture of how amphibian richness is distributed in Chiapas. This information can help to prioritize conservation efforts toward those areas rich in threatened or endemic species, such as the Northern Mountains Hotspot we identified in northern Chiapas. 相似文献
7.
Philip de Pous Wouter Beukema Martijn Weterings Ignas Dümmer Philippe Geniez 《Biodiversity and Conservation》2011,20(1):89-118
The integration of spatial area prioritization algorithms and species distribution modelling has shown great promise in conservation
planning in recent years. However, despite the fact that reptiles and amphibians have the highest threat status of all terrestrial
vertebrates, these species are often under-represented in conservation planning. The Kingdom of Morocco possesses the richest
and most varied herpetofauna in the Maghreb and the western Mediterranean, and is characterized by high species richness,
endemism and number of European relict species. Despite the fact that Moroccan reptiles and amphibians have been the subject
of numerous studies by a large number of international herpetologists since the beginning of the 20th century, few or none
of these concerned their conservation. This study had three main objectives: (1) to identify those areas that harbour the
highest species richness; (2) to evaluate the existing and proposed future ‘important biological and ecological sites’ (SIBES)
conservation area network (CAN) with respect to their ability to protect the herpetofauna adequately; and (3) to identify
priority areas into which the existing protected areas can be augmented. We used maximum-entropy species distribution modelling
to run distribution models for 11 amphibian and 86 reptile species (27.6% endemics and 12.4% threatened) for which we had
2,170 single geographic records. A total of 97 models were used to create a richness map of the Moroccan herpetofauna and
thereby detect both areas of high species richness and the distribution patterns of individual species. This map was subsequently
used as a basis for performance evaluation of the CAN and area prioritization using the ConsNet conservation planning software
initialized by “Rarity” first, while using representation targets of 5% and 10%. Additionally, the proposed future Moroccan
CAN (SIBES) was evaluated in terms of its overlay and proximity with ConsNet solutions using visual interpretation and distance
measurements in a GIS. Our results show that Moroccan herpetofauna is poorly protected under the existing and future CAN.
Prioritization of areas shows that a major increase in conservation area is required to guarantee the persistence of individual
herpetofauna species even with a global minimum representation target of only 10%. An increase of the existing CAN is especially
needed along parts of the Atlantic coast, in the north-western Mediterranean region, on the north-eastern Moroccan coast,
as well as in several areas in the Sahara, notably vast proportions of the Vallée du Haut and Bas Draa. 相似文献
8.
As a process affecting animal communities, urbanization has been the subject of numerous studies. However, amphibians are still among the least studied vertebrate groups in urbanized landscapes. Generally, it has been found that the process of loss of amphibian diversity is nonrandom, with species from older evolutionary lines at greater risk. Regional data on amphibian assemblages in urban areas is a very useful tool for assessing how these assemblages react to changes.The aim of the present paper is to assess the diversity of amphibians in Polish cities based on data in the relevant literature, exploring different metrics (e.g., taxonomic, functional, and evolutionary diversity) calculated in amphibian species assemblages. We used data from 18 articles (including grey literature), characterized by comparable research methods and published between 1999 and 2017.Overall, amphibian species richness (ASR) amounted to an average of 9 species, ranging from 5 to 11 species per city. The higher species richness occurred in Białystok in North-west of Poland. Functional evenness (FEve), evolutionary distinctiveness (ED sum), and functional richness (FRic) were strongly positively correlated with ASR. However, ED mean was not significantly correlated with the total number of species in the community. Three taxa, the hybridogenetic water frogs Pelophylax esculentus complex, the common toad Bufo bufo, and the common frog Rana temporaria, occurred in all analyzed amphibian assemblages. Our study is one of the first attempts to compare urban amphibian assemblages, using different and complementary diversity metrics on a large spatial scale. In conclusion, we highlight that urban areas play an important role for conservation of amphibians, because they support amphibian assemblages characterized by a high level of overall diversity. 相似文献
9.
Charlie J. Gardner Louise D. Jasper Christian Eonintsoa Julio-Josepha Duchene Zoe G. Davies 《Biodiversity and Conservation》2016,25(9):1773-1793
Multiple-use protected areas, in which sustainable levels of extractive livelihood activities are permitted, play an increasingly important role in the global protected area estate, and are expected to rise in prevalence. However, we know little about their effectiveness at conserving biodiversity. We surveyed bird and reptile communities in three areas across a forest disturbance gradient resulting from charcoal production and shifting cultivation within a multiple-use protected area in Madagascar’s sub-arid spiny forest. We scored individual species using a Conservation Value Index (CVI; a simple metric based on rarity, threat and distinctiveness), and estimated the total conservation value of each treatment by calculating the sum of frequency-weighted CVI scores across all present species. Bird and reptile community responses to forest disturbance were idiosyncratic. Bird richness was greatest in the moderate-disturbance treatment, but the low-disturbance treatment had the superior conservation value due to higher frequencies of locally-endemic species. Reptile richness was the same in low- and moderate-disturbance treatments, but the conservation value of the latter was greater. The high-disturbance areas had lowest richness and conservation value for both groups. For birds, increasing disturbance levels were accompanied by community turnover from high-value to low-value species, a pattern highlighted by CVI that is masked by assessing species richness alone. Although some endemic species appear to be resilient to degradation, multiple-use protected areas in Madagascar may lose biodiversity since most endemic species are forest-dependent. Stricter protected area models may be more appropriate in areas where much of the high-value biodiversity is sensitive to habitat degradation. 相似文献
10.
Marco Girardello Matteo Griggio Mark J. Whittingham Stephen P. Rushton 《Ecological Research》2010,25(1):103-111
Analyzing the relationships between the distribution of animal species and climatic variables is not only important for understanding
which factors govern species distribution but also for improving our ability to predict future ecological responses to climate
change. In the context of global climate change, amphibians are of particular interest because of their extreme sensitivity
to the variation of temperature and precipitation regimes. We analyzed species–climate relationships for 17 amphibian species
occurring in Italy using species distribution data at the 10 × 10 km resolution. A machine learning method, Random Forests,
was used to model the distribution of amphibians in relation to a set of 18 climatic variables. The results showed that the
variables which had the highest importance were those related to precipitation, indicating that precipitation is an important
factor in determining amphibian distribution. Future projections showed a complex response of species distributions, emphasizing
the potential severity of climate change on the distributions of amphibians in Italy. The species that will decrease the most
are those occurring in mountainous and Mediterranean areas. Our results provide some preliminary information that could be
useful for amphibian conservation, indicating if future conservation priorities for some species should be enhanced. 相似文献
12.
Mathias Behangana Panta M. B. Kasoma Luca Luiselli 《Biodiversity and Conservation》2009,18(11):2855-2873
Broad-scale ecological correlates affecting species richness and abundance patterns of amphibians were studied in 37 sampling
sites from 15 independent protected areas in the Albertine Rift, East Africa. Amphibians were caught by a combination of sampling
techniques, including time-constrained visual searching, pitfalls with drift fences, dip-netting, and opportunistic observations.
In total, 73 species of amphibians were recorded, some of them occurring only once in the samples and some more than 1,000
times. Once relative field effort at each study site was taken into account, multivariate regression analyses showed that
amphibian species richness was positively influenced by percent canopy cover and altitude. On the other hand, population abundance
was influenced by a combination of three different variables: positively by percent canopy cover and rainfall, and negatively
by human activities. The rainforest proved to play a very important role in the ecological distribution of species, with about
63% of the species being in one way or the other linked to it either as forest specialists, inhabitants of forest ecotones,
or inhabitants of both forests and forest ecotones. These results have wide conservation implications. Indeed, as the mature
rainforest habitat (especially at mid altitude-highland) proved to be the key habitat for the amphibian communities of the
Albertine Rift, it should be a priority to recommend an accurate management and conservation of mature forests in local and
regional protection programs. 相似文献
13.
Distribution patterns of biodiversity and the design of a representative reserve network in Portugal 总被引:6,自引:2,他引:4
Miguel B. Araújo 《Diversity & distributions》1999,5(4):151-163
Representativeness is a desirable property of conservation networks. In this paper an attempt is made to assess the efficiency of current conservation networks in Portugal in representing vertebrates (reptiles and amphibians) and plants (gymnosperms, pteridophytes and bryophytes). It was found that whilst the protected areas do not sample all species in the database they provide a better result than choosing areas at random. For the goal of maximizing representation of taxa per unit area hotspots and complementarity performed better. A pattern of over-representation of vertebrates in relation to lower plants was discovered among selected conservation areas in Portugal suggesting that charismatic organisms with large home ranges may not always be the most appropriate surrogates for biodiversity when representativeness is sought. When trying to fill the gaps in current protected areas with additional areas only complementarity performed better than choosing areas at random. Both rarity and richness hotspots gave worse results. Opportunistic administrative criteria such as supplementing the PAS with other conservation areas (CORINE Biotopes) without taking into account their contribution to a representation goal was nearly half as good as choosing areas at random. The results recall for the need of explicit goals and accountable methods in area selection for conservation and reinforce the role of complementarity for finding additional areas to protected areas when limited resources are available for ‘in situ’ conservation. 相似文献
14.
Spatial conservation prioritization should seek to anticipate climate change impacts on biodiversity and to mitigate these impacts through the development of dynamic conservation plans. Here, we defined spatial priorities for the conservation of amphibians inhabiting the Atlantic Forest Biodiversity Hotspot that overcome the likely impacts of climate change on the distribution of this imperiled fauna. First, we built ecological niche models (ENMs) for 431 amphibian species both for current time and for the mid-point of a 30-year period spanning 2071–2099 (i.e. 2080). For modeling species'' niches, we combined six modeling methods and three different climate models. We also quantified and mapped model uncertainties. Our consensus models forecasted range shifts that culminate with high species richness in central and eastern Atlantic Forest, both for current time and for 2080. Most species had a significant range contraction (up to 72%) and 12% of species were projected to be regionally extinct. Most species would need to disperse because suitable climatic sites will change. Therefore, we identified a network of priority sites for conservation that minimizes the distance a given species would need to disperse because of changes in future habitat suitability (i.e. climate-forced dispersal) as well as uncertainties associated to ENMs. This network also maximized complementary species representation across currently established protected areas. Priority sites already include possible dispersal corridors linking current and future suitable habitats for amphibians. Although we used the a top-ranked Biodiversity Hotspot and amphibians as a case study for illustrating our approach, our study may help developing more effective conservation strategies under climate change, especially when applied at different spatial scales, geographic regions, and taxonomic groups. 相似文献
15.
The combination of species distributions with abiotic and landscape variables using Geographic Information Systems can prioritize
areas for biodiversity protection by identifying areas of high richness, although the number of variables and complexity of
the relationships between them can prove difficult for traditional statistical methods. The use of these methods, which commonly
assume linearity and low correlation between independent variables, can obscure even strong relationships and patterns. Self-Organizing
Maps (SOM) is a heuristic statistical tool based on machine learning methods that can be used to explore patterns in large,
complex datasets for linear and nonlinear patterns. Here we use SOM to visualize broad patterns in species richness by taxonomic
group (birds, mammals, reptiles, and amphibians) and 78 habitat, landscape and environmental variables using data from the
Gap analysis project for West Virginia, USA. Soil and habitat variables demonstrated clear relationships with species richness;
areas with high species richness occurred in areas with high soil richness. Landscape metrics were less important, although
habitat diversity and evenness indices were positively related to species richness in some taxonomic groups. Current coverage
of protected areas (e.g., National Forests and state parks) appeared to be insufficient to cover most of the areas of high
species richness, especially for reptiles; many of the polygons with the highest richness were not covered by these areas.
The identification of polygons with high richness and low protection can be used to focus conservation efforts in those areas. 相似文献
16.
本底资源是保护区建设与发展的基础,也是生物多样性深入研究与保护重要的参考资料。湖南小溪国家级自然保护区是我国中南地区具有代表性的原始次生林区,生物资源相对丰富。自2014年以来,对区内的两栖爬行动物资源、多样性及区系进行了较为系统的调查与研究。结果表明:区内现有两栖爬行动物2目16科40属63种,其中两栖动物1目7科15属33种,爬行动物1目9科25属30种;无声囊泛树蛙Polypedates mutus和老山树蛙Rhacophorus laoshan是湖南省两栖动物新记录;核心区的物种多样性指数和均匀度指数均高于缓冲区和实验区;动物区系成分缺乏古北界种类,以东洋界种类为主(48种,占76.2%),广布种有15种(23.8%);平均动物区系相似性比较发现,其与湖南省内其他6个保护区(森林公园)属于周缘关系。鉴于保护区两栖爬行动物资源的丰富性、典型性与代表性,应加强研究和保护。 相似文献
17.
Leigh J. Martin Brad R. Murray 《Biological reviews of the Cambridge Philosophical Society》2011,86(2):407-419
The invasive spread of exotic plants in native vegetation can pose serious threats to native faunal assemblages. This is of particular concern for reptiles and amphibians because they form a significant component of the world's vertebrate fauna, play a pivotal role in ecosystem functioning and are often neglected in biodiversity research. A framework to predict how exotic plant invasion will affect reptile and amphibian assemblages is imperative for conservation, management and the identification of research priorities. Here, we present a new predictive framework that integrates three mechanistic models. These models are based on exotic plant invasion altering: (1) habitat structure; (2) herbivory and predator‐prey interactions; (3) the reproductive success of reptile and amphibian species and assemblages. We present a series of testable predictions from these models that arise from the interplay over time among three exotic plant traits (growth form, area of coverage, taxonomic distinctiveness) and six traits of reptiles and amphibians (body size, lifespan, home range size, habitat specialisation, diet, reproductive strategy). A literature review provided robust empirical evidence of exotic plant impacts on reptiles and amphibians from each of the three model mechanisms. Evidence relating to the role of body size and diet was less clear‐cut, indicating the need for further research. The literature provided limited empirical support for many of the other model predictions. This was not, however, because findings contradicted our model predictions but because research in this area is sparse. In particular, the small number of studies specifically examining the effects of exotic plants on amphibians highlights the pressing need for quantitative research in this area. There is enormous scope for detailed empirical investigation of interactions between exotic plants and reptile and amphibian species and assemblages. The framework presented here and further testing of predictions will provide a basis for informing and prioritising environmental management and exotic plant control efforts. 相似文献
18.
P. Vera M. Sasa S. I. Encabo E. Barba E. J. Belda J. S. Monrós 《Biodiversity and Conservation》2011,20(6):1287-1317
The establishment of protected areas is traditionally considered indispensable to preserve biodiversity hotspots or areas
inhabited by threatened species. The analysis of correlations between composition or richness of several taxonomic groups
in a specific area has emerged as a useful mechanism to quickly identify areas of biological and conservation interest, and
is currently used to select and design protected areas. The effect of habitat fragmentation on these correlations at a regional
scale has been studied, but the effect of land use on the correlations obtained at local scale is poorly understood. We evaluated
the relationships among different taxonomic groups frequently used in biological assessments for reserve design (vascular
flora, amphibians, reptiles, birds and mammals), taking into account the effects of land use on these correlations. We compared
richness and species composition of these groups in 1 km2 quadrants within a total area of 75 km2 in a low mountain Mediterranean area. Richness and composition were significantly correlated between several groups, both
using the complete data set and also analyzing natural and disturbed areas separately. Species composition and species richness
correlations were not congruent at the full landscape approach, nor natural and disturbed quadrants. Factors extrinsic to
the communities also varied their influence in the assemblage of the community and species richness or not land uses were
taken into account. According to our results, natural and human-disturbed areas should not be combined in cross-taxon congruences
analysis at local scale. 相似文献
19.
There is a pressing need to develop a sound conservation strategy for pool-breeding amphibians, which includes gaining a better understanding of the habitat and landscape-scale characteristics associated with populations. To investigate relationships between amphibian species richness and characteristics of breeding pools and surrounding landscapes, we surveyed 85 pools in eastern Massachusetts (USA) in 1996 and 1997. A total of 11 species was detected, with most pools having 2–5 species. Pools were typically small, 77.6% were <0.2 ha, but most pools (72%) had hydroperiods that persisted at least into August in most years. Based on linear regression analyses, species richness was positively associated with three within-pool variables (pool surface area, hydroperiod, and the amount of emergent vegetation), and a landscape-level variable (presence of another breeding pool within 1 km), while one within-pool variable (tree canopy cover) exhibited a significant negative association with species richness. These within-pool habitat variables and connectivity to other breeding pools are important characteristics to consider when attempting to identify breeding sites that could provide core habitat in conservation reserves designed for the conservation of pool-breeding amphibian species richness. Conservation reserves for pool-breeding amphibian populations should include pool complexes functioning as habitat for metapopulations. Core pool habitats within such reserves should be large (0.5–1.0 ha), with seasonal hydroperiods that persist into August or that dry in some years, and with sufficient emergent vegetation to provide diverse microhabitats and refugia. 相似文献
20.
《PloS one》2014,9(8)