共查询到20条相似文献,搜索用时 31 毫秒
1.
目的 通过对上海市部分三级医院管理人员职业规划现状的调查、分析,探寻管理人员职业规划的适宜方法,并提出应对举措和政策支持,为推进公立医院持续发展助力。方法 研究选取上海市5家三级综合性医院、1家三级专科医院和1家中医类三级医院抽样,采用问卷形式对抽样人群进行基本情况、职业状态和职业规划现状的调查。结果 医院管理人员职业规划滞后,职业发展途径不畅,部分管理者晋升受阻。自身性格特质和学历、月薪收入成为影响职业规划与职业状态满意度的重要因素。结论 公立医院管理人员梯队建设不容忽视,引导管理人员进行职业规划、畅通职称晋升途径、提高职业归属感是保障公立医院持续发展的重要一环。 相似文献
2.
Capsule Nestbox orientation has species-specific influences on nestbox occupation and breeding success for woodland passerines. Aims To determine if nestbox orientation had an influence upon nestbox selection or breeding success for three co-occurring woodland passerines. Methods We analysed 15 consecutive years of breeding data (1990–2004) from 295 nestboxes in the UK using circular statistical analyses to examine the influence of orientation upon nestbox occupation and breeding success for three species, Blue Tit Cyanistes caeruleus, Great Tit Parus major and Pied Flycatcher Ficedula hypoleuca. Results The three species used nestboxes of all orientations during the 15-year period. The frequency of nestbox occupation by Great Tits correlated with orientation (the mean number of nests in boxes oriented south-southwest was lower than the mean number of nests in boxes facing other directions). There was no such relationship for Blue Tits or Pied Flycatchers. Nestbox orientation influenced the breeding success of Pied Flycatcher (the mean number of young to fledge from boxes oriented south-southwest was lower than from boxes facing other directions). There was no such relationship for Blue or Great Tits. Conclusion Nestbox orientation can be an important influence on occupation and breeding success, but this differed between species. Intriguingly, although the directionality reduced nestbox occupation (Great Tit) and breeding success (Pied Flycatcher) was the same (south-southwest), there was a disparity in the influence of orientation for Great Tit (orientation influenced the frequency of occupation but not success) and Pied Flycatcher (orientation did not influence occupation but did affect success). We discuss these disparities, considering the possible influences of mating strategy, breeding phenology, nestbox microclimate and offspring quality. 相似文献
3.
Guillermo Blanco Óscar Frías Jesús A. Cuevas José L. González Félix Martínez 《Bird Study》2013,60(3):351-360
Capsule The hypothesized regional population size of a common species in Spain was found to be unreliable when compared with a complete and simultaneous single-species direct census.Aims To provide a regional census of Eurasian Jackdaws Corvus monedula as an example to highlight the crucial importance of baseline knowledge of actual population size of common species for validation and calibration of population size predictions derived from extrapolation.Methods Population size was measured by means of simultaneous counts of winter communal roosts after determining the best census date and other relevant information on flock routines, foraging areas and potential sources of count variability.Results A large discrepancy between hypothesized (~330?000 individuals) and directly censused population size (~15?000 individuals) was recorded.Conclusion Programmes aimed at establishing population size of wildlife by statistical inference should attempt to explicitly test their predictions by comparison with directly censused population sizes of particular species in control areas. 相似文献
4.
D.R. Slingsby 《Plant Ecology & Diversity》2013,6(4):297-306
Summary Distribution and population size of six of the rarer plant species on the Keen of Hamar, including the endemic Cerastium arcticum ssp. edmondstonii, are presented. Changes in populations over recent years are described. The part of the Keen designated a National Nature Reserve includes many of the important geomorphological and botanical features of the site but excludes considerable numbers of rarities including most of the C. arcticum. Possible threats to the site and the need to enlarge the NNR are discussed. 相似文献
5.
《Plant Ecology & Diversity》2013,6(2-3):175-184
Background: Ecological surveys often aim to inform biodiversity conservation policy and practice. Survey types differ; all require clear aims and good design. A survey in Scotland was carried out to measure the distribution and health of juniper (Juniperus communis) and potential for its natural regeneration.Aims: Explore if one-off national surveys can inform conservation action by examining, as an example, the Scottish juniper data set to: (1) determine site conditions favourable for juniper regeneration, (2) provide recommendations for site management for regeneration.Methods: Associations between site conditions and juniper occurrence were investigated with principal component analysis (PCA) and using species distribution modelling (SDM). To identify changes in site conditions over time, we compared degree of site suitability for natural regeneration (PCA distance) and population age structure.Results: Twenty-one per cent of the sites showed juniper regeneration. Compared to all juniper sites, conditions at regenerating sites were different (e.g. climatically wetter, lower site fertility). Change over time in conditions was suggested by patterns in population age structure.Conclusions: Following the establishment of a juniper population, site conditions may change, becoming unsuitable for natural regeneration. Historical site information to confirm this is lacking. We cannot answer fundamental questions about the causal mechanisms of the natural regeneration of juniper and question whether one-off survey data can inform conservation management. 相似文献
6.
Jack J. Windig Pekka T. Rintamäki Anna Cassel Sören Nylin 《Journal of Insect Conservation》2000,4(4):253-261
It has been suggested that minor, fluctuating differences in size of bilateral traits could validly indicate individual differences in developmental stability. One plausible reason for instability to occur could be lowered population size, which has been suggested to increase fluctuating asymmetry due to inbreeding, for example. We measured seven wing asymmetries of three Coenonympha butterfly species in central Sweden. One species is abundant (nobreak C. pamphilus), one rather common (C. arcania), and one rare (C. hero). We expected that if fluctuating asymmetry is a reliable indicator of population quality and thus a useful tool for conservation purposes, the most abundant species should show lowest asymmetry and the most endangered, the highest. Contrary to our expectations, the highest wing asymmetry was found in the relatively common species C. arcania and the most abundant and rare species did not show significant differences in levels of wing asymmetry. Our results obtained from three Coenonympha species hence suggest that the use of fluctuating asymmetry as an indicator of population conservation status may be misleading. Possible increase in asymmetry of small and/or isolated populations of butterflies may be masked by local differences in environmental conditions that could have high impact on bilateral development as well. 相似文献
7.
《Plant Ecology & Diversity》2013,6(3):371-376
Background: Economic activities are substantial factors in alien plant establishment and invasions. Climate also plays an important role in the distribution of alien species.Aims: We evaluate the relationship between alien species density and both climatic and socio-economic factors at the scale of provinces located in a latitudinal-bioclimatic gradient in Chile.Methods: We used generalised linear models with backward selection to evaluate the relative importance of each parameter (human population, gross domestic product, length of traffic routes, crop cover, abandoned crop cover, artificial plantations, protected areas, annual rainfall and temperature) on species density. We compared the average species density among climate types.Results: Alien density was higher for provinces located in the most populated areas with Mediterranean and temperate oceanic climates (south-central Chile) and decreased for less populated provinces in the north and the southernmost parts (desert and sub-Antarctic wetlands). Human population, length of traffic routes and annual rainfall significantly explained the variation in alien species density in Chile.Conclusions: Although human population still increases, the results can be used especially in high priority conservation areas where traffic routes and human settlements can be objectively reduced or managed, to reduce the potential increase in the number of alien species. 相似文献
8.
A suite of ecological and genetic factors are likely to contribute to reintroduction performance. Potential factors include the ecological similarity between seed source and introduction site, population size and genetic diversity of seed sources, and the habitat quality of the introduction site. We conducted common garden experiments with golden paintbrush (Castilleja levisecta), an endangered species from the Pacific Northwest, U.S.A., in order to test hypotheses about reintroduction performance and to provide management recommendations. Ten common gardens, each composed of C. levisecta individuals grown from seed from six of the remaining populations, were planted into field conditions and monitored during two growing seasons. Plant community characteristics were important predictors of observed variation in C. levisecta performance. Exotic species‐cover at common garden sites was associated with a reduction in performance of first‐year C. levisecta transplants, while survival to the second growing season increased with increasing similarity in plant functional groups between source and common garden sites. Although measures of genetic diversity, population size, and geographic distance are often used to make conservation decisions during species recovery, here they were poor predictors of C. levisecta performance and establishment. We recommend choosing material for reintroduction from ecologically similar habitats, rather than those most proximate geographically, and selecting recovery sites with low exotic species abundance. 相似文献
9.
The loss of parasitism in metazoan lineages is often seen as unlikely, but it has occurred in some lineages (e.g., leeches, lampreys). How and why parasitism is lost is aptly addressed by studying lampreys, because extant species include a range of feeding modes and parasitism has been lost repeatedly. An individual‐based model was developed to determine whether variations in survival and growth rates in the larval and juvenile stages could favour parasitic or nonparasitic strategies. A realization of the model for a Lampetra spp. population, a genus which includes parasitic and nonparasitic animals, indicated that both strategies could be successful. A different model realization of the nonparasitic species Lethenteron appendix also agreed with expectations, and only nonparasitic strategies were successful. Modelling anadromous Petromyzon marinus produced only parasitic animals, as expected, but suggested two different adult sizes should appear in the population, which has not been reported in the literature. Finally, a realization of an Ichthyomyzon castaneus population, known to be parasitic only, rarely selected for parasitism (c. 7% of model iterations), possibly because the population used to parameterize the model was unusual for the species. The results suggest that nonparasitic lineages in lampreys are common because parasitism, while offering better growth, also has lower survival. Additionally, nonparasitic species may be generated at different rates because growth and survival thresholds in the model favouring parasitism are close to observed estimates in some populations. Loss of parasitism can occur when life stages have different trade‐offs in growth and survivability. 相似文献
10.
Deviations of the site frequency spectrum of mutations (SFS) from neutral expectations may be caused by natural selection or by demographic processes such as population subdivision or temporal changes in population size. As most widespread temperate and boreal tree species have expanded from glacial refugia in the past 13 000 years, colonization bottlenecks associated with this migration may have left variable demographic signatures among geographic populations corresponding to distance from the refugia. To determine whether the signature of postglacial re‐colonization has skewed the SFS in the widely distributed conifer Sitka spruce (Picea sitchensis (Bong.) Carr.), we re‐sequenced 153 nuclear genes in six populations from across the species range. We found that while the SFS for the pooled sample produced negative values for Tajima’s D and Fay and Wu’s H, these statistics exhibited strong clinal variation when populations were analysed separately (R2 = 0.84, P = 0.007 for Tajima’s D and R2 = 0.65, P = 0.033 for Fay and Wu’s H). When historical bottlenecks of varying age were simulated using approximate Bayesian computation, distance of populations from the southern range limit explained most of the variation in bottleneck timing among populations (R2 = 0.89, P = 0.003). These data suggest that sequential population bottlenecks during postglacial re‐colonization have resulted in diverse among‐population signatures within the contemporary SFS in Sitka spruce, with rare variants more common in the south, and medium‐frequency variants more common in the north. Our results also emphasize the need to consider sampling strategy and to explore population‐specific null demographic models in surveys of nucleotide variation in widely distributed species. 相似文献
11.
Alexander N. Banks Humphrey Q.P. Crick Rachel Coombes Stuart Benn Derek A. Ratcliffe 《Bird Study》2013,60(4):421-436
Capsule Numbers of breeding Peregrines are now higher than ever recorded and the recovery of the species within the UK has continued since 1991. Aims To estimate the current Peregrine breeding population and its changes over time by recording breeding evidence and nesting range occupancy at known and potential Peregrine eyries. Methods Attempts were made to check all potentially suitable Peregrine nesting locations for signs of Peregrine occupation. Causes of nest failure were documented where possible. Estimates of occupancy of nesting ranges that could not be visited were based on the proportion of ranges occupied from visited nesting ranges in the same region. Results In 2002, 1530 Peregrine nesting ranges were estimated to be occupied, comprising 1456 pairs or single birds confirmed as in occupation, and 74 estimated extras (5% of total occupied nesting ranges) that were not visited. Including non‐breeding singletons holding nesting ranges, the UK and Isle of Man figure of ‘Ratcliffe pairs’ was 1437. This showed a 12% increase from 1991 and a 64% increase from the 1930s. However, there were geographical differences in change, with rapid expansion in the south of England tempered by declines in northern Scotland. Conclusions The primary reasons for the population increase is primarily because of range expansion driven by a plentiful food supply and perhaps an increased tolerance of human disturbance. In areas where the species has declined, various factors (separately or in combination) including reduced food supply and persecution are likely to be involved. 相似文献
12.
Low levels of intraspecific genetic variation at a rapidly evolving chloroplast dna locus in North American duckweeds (Lemnaceae) 总被引:1,自引:0,他引:1
Although most previous studies on chloroplast (cp) DNA variation in plants have concentrated on systematics and evolution above the species level, intraspecific variation in cpDNA is common and has provided useful insights into population-level evolutionary processes. Polymerase chain reaction methods were used to examine restriction site and sequence variation in the chloroplast rpLI6 gene within and among populations of duckweed species (Spirodela and Lemna) from the southern and eastern United States. To our knowledge, the rpL16 region has not previously been used to investigate cpDNA variation in nature. While considerable restriction site and sequence variation were detected among species, no variation was found within populations of either of the two species (S. punctata and L. minor) selected for sequence analysis, and S. punctata showed no interpopulational variation. Two cpDNA haplotypes were identified in L. minor, with one haplotype restricted to three sites in Louisiana and the other found in all other populations sampled. This paucity of variation cannot be readily explained as the result of a low mutation rate. In general, group II introns appear to be subject to very little functional constraint, and extensive sequence differences have been found between species in the chloroplast rpL16 intron in particular. However, factors such as historical range expansions and contractions, founding effects, fluctuations in local population size, and natural selection may play a role in reducing cpDNA sequence variability in these species. 相似文献
13.
Capsule Winter Gull Roost Survey data spanning 50 years were used to generate population indices. Aims To evaluate how wintering numbers of five gull species have changed in Great Britain over the last five decades. Methods Generalized linear models were used to relate gull numbers to habitat, site and year factors, and so derive species‐specific indices for nine regions of Great Britain. Regional models considered data from different timescales depending on coverage. Results Patterns of change varied by species and region. All species showed increases in number over the period 1953 to 2004. In most regions, Black‐headed Gull Chroicocephalus ridibundus numbers have declined since peaks between 1973 and 1993; Common Gulls Larus canus have also declined recently in some regions. Lesser Black‐backed Gull L. fuscus numbers have increased dramatically since 1953, whereas numbers of Herring Gull L. argentatus showed large declines between 1963 and 1983. Great Black‐backed Gull L. marinus numbers have increased in the west and the Midlands, but recently declined in eastern regions. Conclusions Numbers of wintering gulls in Great Britain have shown rapid changes over the last five decades, reflecting changes in the sizes of breeding populations. These changes are likely to be associated with changes in human activities and resource availability. 相似文献
14.
Stuart E. Newson Dario Massimino Alison Johnston Stephen R. Baillie James W. Pearce-Higgins 《Bird Study》2013,60(3):384-390
Capsule?Accounting for changes in detectability over time which could invalidate population trends for common and widespread breeding birds in the UK, resulted in little change in trends for the majority of species considered. Aims?To examine whether detectability has a significant influence on population trends for common and widespread breeding birds in the UK. Methods?Using data collected over 16 years of the UK Breeding Bird Survey (1994–2009) and focusing on a random sample of 20 common and widespread bird species, we examine the extent to which controlling for temporal change in detectability would influence national population trends. Results?Population trends were significantly different for only 2 of the 20 species, Common Blackbird and Winter Wren. This difference corresponds to an apparent fall off in detectability of these species between 2005 and 2009. For the remaining species, controlling for detectability resulted in no significant difference in population trends. Conclusions?The importance of detectability should be examined as part of any long-term monitoring programme. However, currently we do not find sufficient support for routinely incorporating detectability into population trends for widespread and abundant breeding birds in the UK. 相似文献
15.
《Plant Ecology & Diversity》2013,6(4):537-545
Background: Understanding the role of livestock grazing on plant diversity can be improved by an accurate measurement of diversity at all hierarchical scales due to the changeability of diversity components in space.Aims: We evaluated the effects of grazing on plant species diversity at different scales of all common and rare species in two regions that have different climatic conditions (arid vs. semi-arid).Methods: In each region, we collected abundant data of plant species from a nested sampling design that consisted of local (80 plots) and regional (16 sites) scales. We partitioned total species diversity (γ) into within plots (αl), among plots (βl) and among sites (β2) using the additive partitioning.Results: Diversity among sites contributed the most to total diversity for all and rare plant species in both regions. In addition, α1 and β1 diversities in ungrazed areas were greater than those in grazed areas for all and common species in both climates.Conclusion: Abandonment of grazing after 10 years resulted in significant regeneration of common species at the local scale, with no change in rare species. We conclude that low grazing intensity is likely to be an important tool for conservation of plant diversity in which all scales should be considered. 相似文献
16.
Kieran Lawton Graham Robertson Roger Kirkwood José Valencia Roberto Schlatter David Smith 《Polar Biology》2006,29(3):229-238
The Diego Ramirez Islands lie 60 nautical miles southwest of Cape Horn and are the breeding site for three species of burrowing
seabirds: blue petrels (Halobaena caerulea), common diving petrels (Pelecanoides urinatrix) and sooty shearwater (Puffinus griseus). Burrowing seabirds are highly vulnerable to predation by introduced vertebrate pests, and Diego Ramirez is an important
breeding site because it is one of a few remaining subantarctic island groups with no introduced predators. Diego Ramirez
is the only known breeding site for blue petrels in the southeast Pacific region, holding about 80% of the global population
of that species, and with a population ten times larger than any other population in the world. We estimated the population
size in 2002, using a novel application of the distance sampling technique to determine burrow density, and a burrow-scope
with excavations to determine occupying species. We found that density was correlated with slope angle and soil wetness. Burrow
densities in flatter terrain with drier soils were 2.03 burrows/m2 (95% confidence intervals: 1.82–2.27) and 1.11 burrows/m2 (0.84–1.48) in steeper terrain with wetter soils. The occupation rate of burrows were significantly different between habitat
types (t=2.74, d.f. 11, P<0.05); in flatter drier habitats the proportion of burrows that led to a nest was 0.85 (0.74–0.96), in steeper wetter habitats
this decreased to 0.64 (0.50–0.78). We used a digital elevation model to calculate true area rather than planar area for the
two habitat types on the main island of Bartolome, and charts to calculate planar area for the remainder of the archipelago.
There were 1.35 (1.15–1.54) million pairs of blue petrels and 99,000 (65,000–134,000) pairs of common diving petrels on the
archipelago. These are similar figures to those from the only previous estimate, made in 1980. We found breeding sooty shearwaters
for the first time, and estimated a population of several thousand pairs. We emphasise the facility of distance sampling as
an unbiased technique with practical advantages over commonly used area search methods for monitoring populations of burrowing
seabirds. These advantages include increased survey efficiency allowing a larger sample size for a given effort and a correspondingly
tighter estimation of density. 相似文献
17.
《Plant Ecology & Diversity》2013,6(4):529-540
Background: All human land use (LU) affects the distribution of plant species; however, the impacts vary with the type/intensity of LU. For managing ecosystems, it is therefore essential to understand the effects of LU types on the distribution of plant species on a macroscale.Aims: The objectives of our study were to quantify the effects of various LU types on the distribution of vascular plant species in Japan and to determine in particular the extent to which LU was an important factor for the distribution of common species.Methods: Based on a logistic regression model and variation partitioning being applied to each plant species, we evaluated the partial deviance by six LU types, four climatic types and three topographic and geological factors for 647 plant species at 14,412 sites in Japan.Results: The effect of LU was significant for species present at multiple sites. Of the six LU types, secondary vegetation and plantation were the most important factors determining species distribution for many species.Conclusions: Our results suggest that distribution of the common species is largely affected by LU on macroscale. The design of LU relating to secondary vegetation and plantations will thus be important in determining changes in the vegetation composition within Japan. 相似文献
18.
Daniel B. Hayhow Mark A. Eaton Andy J. Stanbury Andy Douse Mick Marquiss 《Bird Study》2018,65(1):36-43
Capsule: The first national survey for Snow Bunting Plectrophenax nivalis in the UK was carried out in 2011 and estimated the breeding population at 60 territories (95% confidence intervals?=?48–83).Aims: To estimate breeding population size for Snow Buntings in the UK by surveying all sites with a history of breeding season occupation.Methods: Surveys were carried out in June 2011 to detect males on territory at sites where Snow Bunting had been recorded during the breeding season since 1970. Each site was visited at least once during the survey period; suitable habitat was searched and vantage point watches were conducted in order to detect singing males. Repeated visits to a sample of sites allowed a correction factor to be calculated in order to account for birds undetected during surveys.Results: In 2011, the number of Snow Bunting breeding in the UK (including adjusting for imperfect detection) is a minimum of 60 territories (95% CI?=?48–83) using confirmed and probable breeding records of males. A less conservative estimate of 99 territories (95% CI?=?88–114) results from including all records of males in suitable habitat. The vast majority of the population was found in the Cairngorm region, with isolated records in the north and west Highlands.Conclusion: The results of the 2011 survey are consistent with well-informed estimates of the Snow Bunting population made previously. This work provides a baseline and repeatable fieldwork and analytical methods enabling future change in the population to be quantified more rigorously. 相似文献
19.
Andrew R. Blaustein 《Oecologia》1981,48(1):71-78
Summary The population dynamics of three sympatric rodents, Microtus californicus, Mus musculus, and Reithrodontomys megatolis was studied at four sites in coastal southern California. The study was undertaken to determine the extent of local demographic diversity in rodent populations.The populations of all rodent species became extinct on one site, while on another site the populations fluctuated widely and on two other sites the populations remained relatively stable. The most common species, Reithrodontomys, exhibited differences in reproduction, age class structure, recruitment, and survivorship on the two sites which were monitored for relatively long terms. Immigration was the main source of new individuals entering the sites where the Reithrodontomys population was most persistent.On a local scale, some life history characteristics are affected in a density dependent fashion. When viewed on a global scale, the non-equilibrium nature of the rodent populations becomes clear. 相似文献
20.
The new species Kadua haupuensis is described and illustrated from the isolated Mt. Ha’upu region of Kaua’i, Hawaiian Islands. This new species belongs to
Kadua subg. Kadua sect. Wiegmannia. It is characterized by a subdioecious (leaky dioecious) breeding system and appears most closely related to another apparently
dioecious species endemic to Kaua’i, Kadua flynnii, with which it is compared. Although the only original wild population is critically endangered and may possibly be extinct,
this new species has been successfully propagated and is currently secure in cultivation. 相似文献