首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
《Ibis》1930,72(4):560-564
  相似文献   

2.
3.
Flammability dynamics in the Australian Alps   总被引:1,自引:0,他引:1       下载免费PDF全文
Forests of the Australian Alps (SE Australia) are considered some of the most vulnerable to climate change in the country, with ecosystem collapse considered likely for some due to frequent fire. It is not yet known, however, whether increasing fire frequency may stabilize due to reductions in flammability related to reduced time for fuel accumulation, show no trend, or increase due to positive feedbacks related to vegetation changes. To determine what these trends have been historically, dynamics were measured for 58 years of mapped fire history. The 1.4 million ha forested area was divided into broad formations based on structure and dominant canopy trees, and dynamics were measured for each using flammability ratio, a modification of probability of ignition at a point. Crown fire likelihood was measured for each formation, based on satellite‐derived measurements of the 2003 fire effects across a large part of the area. Contrary to popular perception but consistent with mechanistic expectations, all forests exhibited pronounced positive feedbacks. The strongest response was observed in tall, wet forests dominated by Ash‐type eucalypts, where, despite a short period of low flammability following fire, post‐disturbance stands have been more than eight times as likely to burn than have mature stands. The weakest feedbacks occurred in open forest, although post‐disturbance forests were still 1.5 times as likely to burn as mature forests. Apart from low, dry open woodland where there was insufficient data to detect a trend, all forests were most likely to experience crown fire during their period of regeneration. The implications of this are significant for the Alps, as increasing fire frequency has the potential to accelerate by producing an increasingly flammable landscape. These effects may be semi‐permanent in tall, wet forest, where frequent fire promotes ecosystem collapse into either the more flammable open forest formation, or to heathland.  相似文献   

4.
Thom  Dominik  Seidl  Rupert 《Ecosystems》2022,25(3):603-617
Ecosystems - Climate change alters forest development pathways, with consequences for ecosystem services and biodiversity. As the rate of warming increases, ecosystem change is expected to...  相似文献   

5.
《Ibis》1929,71(3):492-498
  相似文献   

6.
During our observations in the SE part of the Carnic Alps in the year 2003 we were able to collect and identify 35 ascomycetes on trees and dead wood. Among these one can find numerous ascomycetes of different orders e.g. Pyrenomycetes, Loculoascomycetes and Discomycetes. Some species like Botryosphaeria ribis GROSENLUCHER & DUGGAR on Ribes alpinum L., Dothiora pyrenophora (FR.) FR. on Sorbus aucuparia L., Gemmamyces piceae (BORTH.) CASAGO. on Picea excelsa (LAM.) LINK, Glomerella montana (SACC.) v. ARX & E. MULLER on Sesleria caerulea (L.) ARD, Hymenoscyphus immutabilis (Fuck.) Dennis on Alnus incana (L.) Moench, Hysterographium fraxini (PERS. Ex. FR.) de Not. on Fraxinus ornus L., Lachnellula willkommii (Hartig) DENNIS [= Trichascyphella willkommii (Hartig) NANNF.] on Larix decidua MILL.,Leptosphaeria lycopodina (Mont.) SACC. on Lycopodium annotinum L., Mollisia adenostylidis REHM. on Adenostyles glabra (MILL.) DC., Pezicula cinnamomea (DC.)SACC. [ana: Cryptosporiopsis quercina PETRAK] on Quercus robur L., Pyrenopeziza petiolaris (A. & S. Ex FR.) NANNF. on Acer pseudoplatanus L., Tapesia rosae (PERS.) FUCKEL on Rosa canina L., are new for this area. All specimen are deposited in the Herbarium ESS Mycotheca Parva, Collection G.B. Feige/N. Ale-Agha.  相似文献   

7.
暮色茫茫,夕阳西下,余辉晕染着阿尔卑斯群山。一个远离家人的牧羊人,独自站在山巅,在羊群默默的陪伴下,吹起了长长的号角,用那悠长的呜咽向群山诉说着不尽的惆怅。这样一副忧郁的画面贯穿了阿尔卑斯长号五百多年的漫长历史,它似乎将这种在一代代阿尔卑斯山民中流传的古老乐器永远地留在了过去,成为了历史长诗中一个不再跳跃的音符。在  相似文献   

8.
9.
Management of the feral Horse (Equus caballus) in the Australian Alps bioregion is a difficult and emotive issue, with interested parties working from vastly differing perspectives. Compounding this, information regarding ecology and distribution of horses, and the cost and effectiveness of management strategies is often unknown or uncertain. Resolving these issues requires an objective approach with the flexibility to incorporate different potential scenarios. We used a spatially explicit population model to compare the potential effects of two different management strategies on populations of horses in the Australian Alps bioregion: culling from helicopters versus trapping and mustering. We populated the model using the results of population surveys conducted in 2014, vegetation data and cost estimates. We then provided an estimate of the effect of each strategy on population size across the Alps, and their corresponding costs, compared to no management. To account for uncertainties, we simulated different scenarios for horse population densities, dispersal rates and population growth rates. Management using aerial culling was more effective than mustering in every scenario modelled, and three to six times cheaper. Aerial culling was only slightly more effective within its control region. However, because mustering is necessarily restricted by road access, this translated to a substantial improvement in population control – up to 2000 horses where growth and dispersal rates were high. Our results unequivocally suggest aerial culling as the only strategy that could effectively control horses within the modelled range of scenarios; this result stands in addition to its other potential benefits of lower cost, animal stress and landscape disturbance. A major advantage of this modelling approach is that we can easily update it with new data, test different measures of effectiveness and add new scenarios to adapt to the rapidly changing situation on the ground, both in terms of the ecology and the political climate.  相似文献   

10.
The 6th European Meiosis Workshop, sponsored by EMBO and organized by Franz Klein of the University of Vienna, met in mid-September. More than 150 participants who have not discovered anything more interesting than sex gathered in a bucolic Alpine valley near the town of Obertraun, Austria, surrounded by granite massifs.  相似文献   

11.
In addition to the collection of Ascomycotina in the Carnic Alps (see New, rare or remarkable microfungi in the Italian Alps (Carnic Alps) part I ) we were able to treasure about 300 species of parasitic and saprophytic microfungi. Among them Basidiomycetes, Ascomycetes and Deuteromycets like Bostrichonema polygoni (UNGER) SCHROT. on Polygonum viviparum L., Chrysomyxa rhododendri DE BY on Picea abies (L.) KARSTEN, Coleosporium tussilaginis (PERS.) BERK. I=C. cacaliae OTTH.] on Adenostyles glabra (MILL.) DC., Dasyscyphus barbatus (KUNZE) MASSEE on Lonicera nigra L., Leptosphaeria coniothyrium (FUCKEL) SACC. on Rosa canina L., Leptotrochila brunellae (LIND) DENNIS on Prunella grandiflora (L.) SCHOLLER., Marssonina kriegeriana (BES.) MAGNUS on Salix reticulata L., Puccinia alpina FUCKEL on Viola biflora L., Puccinia maculosa (STRAUSS.) ROHLING and Erysiphe cichoracearum DC. On Prenanthes purpurea L., Septoria microsora SPENG. on Gentianella germanica (WILLD.) BORNER, Urocystis orobranches (FR.) FISCH. V. WALDH. on Orobranche gracilis SM., Urocystis violae (J. SOWERBY) A. FISCHER VON WALDHEIN on Viola biflora L. and Uromyces phyteumatum (DC.) UNG. on Phyteuma spicatum L. were dominant. All samples are located in the Herbarium ESS Mycotheca Parva, Collection G.B. Feige/N. Ale-Agha.  相似文献   

12.
Evidence for reduced sensitivity of tree growth to temperature has been reported from multiple forests along the high northern latitudes. This alleged circumpolar phenomenon described the apparent inability of temperature-sensitive tree-ring width and density chronologies to parallel increasing instrumental temperature measurements since the mid-20th century. In addition to such low-frequency trend offset, the inability of formerly temperature-sensitive tree growth to reflect high-frequency temperature signals in a warming world is indicated at some boreal sites, mainly in Alaska, the Yukon and Siberia. Here, we refer to both of these findings as the ‘divergence problem’ (DP), with their causes and scale being debated. If DP is widespread and the result of climatic forcing, the overall reliability of tree-ring-based temperature reconstructions should be questioned. Testing for DP benefits from well-replicated tree-ring and instrumental data spanning from the 19th to the 21st century. Here, we present a network of 124 larch and spruce sites across the European Alpine arc. Tree-ring width chronologies from 40 larch and 24 spruce sites were selected based on their correlation with early (1864–1933) instrumental temperatures to assess their ability of tracking recent (1934–2003) temperature variations. After the tree-ring series of both species were detrended in a manner that allows low-frequency variations to be preserved and scaled against summer temperatures, no unusual late 20th century DP is found. Independent tree-ring width and density evidence for unprecedented late 20th century temperatures with respect to the past millennium further reinforces our results.  相似文献   

13.
This study contributes to an update of average heights among European populations. Our investigation covering 2705 boys and 2842 girls aged 17 years, shows that, contrary to the general belief, adolescents of the Dinaric Alps are, on average, the tallest in Europe. With an average height of 185,6 cm, they are taller than Dutch adolescents (184 cm on average). Above all, the density of very tall subjects appears to be characteristic of the Dinaric Alps, since 28% measure 190 cm or more in height, as opposed to only 20% in Holland and 1.5% in France. Although our information is not complete, adolescent girls in the Dinaric Alps, with an average height of 171 cm come a close second to girls in Holland.  相似文献   

14.

Background

The boreal forest of Canada is home to several hundred thousands Aboriginal people who have been using medicinal plants in traditional health care systems for thousands of years. This knowledge, transmitted by oral tradition from generation to generation, has been eroding in recent decades due to rapid cultural change. Until now, published reviews about traditional uses of medicinal plants in boreal Canada have focused either on particular Aboriginal groups or on restricted regions. Here, we present a review of traditional uses of medicinal plants by the Aboriginal people of the entire Canadian boreal forest in order to provide comprehensive documentation, identify research gaps, and suggest perspectives for future research.

Methods

A review of the literature published in scientific journals, books, theses and reports.

Results

A total of 546 medicinal plant taxa used by the Aboriginal people of the Canadian boreal forest were reported in the reviewed literature. These plants were used to treat 28 disease and disorder categories, with the highest number of species being used for gastro-intestinal disorders, followed by musculoskeletal disorders. Herbs were the primary source of medicinal plants, followed by shrubs. The medicinal knowledge of Aboriginal peoples of the western Canadian boreal forest has been given considerably less attention by researchers. Canada is lacking comprehensive policy on harvesting, conservation and use of medicinal plants. This could be explained by the illusion of an infinite boreal forest, or by the fact that many boreal medicinal plant species are widely distributed.

Conclusion

To our knowledge, this review is the most comprehensive to date to reveal the rich traditional medicinal knowledge of Aboriginal peoples of the Canadian boreal forest. Future ethnobotanical research endeavours should focus on documenting the knowledge held by Aboriginal groups that have so far received less attention, particularly those of the western boreal forest. In addition, several critical issues need to be addressed regarding the legal, ethical and cultural aspects of the conservation of medicinal plant species and the protection of the associated traditional knowledge.  相似文献   

15.
Evolutionary Ecology - The evolution of male-male aggression is of interest because at its extreme it can be very energetically costly, leave males vulnerable to preadtors, and give rise to...  相似文献   

16.
17.
New data from the Berchtesgaden Alps result in a reconstruction of the Mesozoic-Cenozoic geodynamic history of the Northern Calcareous Alps. The closure of the western part of the Neotethys Ocean started in the late Early Jurassic and is evidenced by the onset of thick clay-rich sediments in the outer shelf area (=Hallstatt realm). The Middle to early Late Jurassic contraction is documented by the migration of trench-like basins formed in front of a propagating thrust belt. Due to ophiolite obduction, these basins propagated from the outer shelf area, forming there the Bajocian to Oxfordian Hallstatt Mélange, to the Hauptdolomit/Dachstein platform area, where the Oxfordian Rofan and Tauglboden Mélanges were formed. The basins were separated by nappe fronts forming structural highs. This scenario mirrors syn-orogenic erosion and deposition in an evolving thrust belt. Active basin formation and nappe thrusting ended around the Oxfordian/Kimmeridgian boundary, which was followed by the onset of carbonate platforms on structural highs prograding towards the former basins in latest Oxfordian to Early Tithonian time. Underfilled basins remained between the platforms. Rapid deepening around the Early/Late Tithonian boundary was induced by extension due to mountain uplift and resulted in the reconfiguration of the platforms and basins related to normal and probably strike-slip faults. Erosion of the uplifted nappe stack including obducted ophiolites caused final drowning and demise of the platforms in the Berriasian. The remaining Early Cretaceous basins were filled up with molasse sediments including siliciclastics until Aptian. Around the Early/Late Cretaceous boundary again extension and strike-slip movements started, followed by Eocene thrusting and Miocene strike-slip movements with block rotations. These younger tectonic movements destroyed the Triassic to Early Cretaceous palaeogeography and arranged the modern block configuration. The described Jurassic to Early Cretaceous history corresponds with that of the Western Carpathians, the Dinarides, and the Albanides, where (1) age dating of the metamorphic soles prove late Early to Middle Jurassic inneroceanic thrusting followed by late Middle to early Late Jurassic ophiolite obduction, (2) Kimmeridgian to Tithonian shallow-water platforms formed on top of the obducted ophiolites, and (3) latest Jurassic to Early Cretaceous sediments show postorogenic character. Therefore, we correlate the Jurassic geodynamic evolution of the Northern Calcareous Alps with the closure of the western part of the Neotethys Ocean.  相似文献   

18.
Soil diaspore reserves are considered to support self-healing processes after vegetation disturbances. Therefore, the stratified reserves of viable diaspores in superimposed soil layers of four sites above the timberline in the Austrian Alps were assessed. At each site, a semi-natural (“undisturbed”) extensive alpine pasture and the disturbed vegetation on hiking trails were investigated. Eighty soil cores in total (corresponding to 400 slices, each representing a 1-cm layer between 0 and 5 cm depth) were taken in autumn and subjected to germination tests after vernalization. The total diaspore numbers in disturbed and undisturbed plots did not differ significantly, but all undisturbed soils contained higher species numbers than disturbed ones. Seed shape and size clearly influenced the vertical distribution. Intact soils showed a significant decrease in big/long diaspores with increasing soil depth. Disturbances influenced the aboveground species composition and therefore the distribution of seeds of different size. In case of disturbances, the restriction of most big seeds to superficial layers means a threat for small populations of rare and protected species such as Viola lutea subsp. sudetica with relatively big seeds near the soil surface. When the disturbances stop, the diaspore communities might initiate a first, but with respect of landscape protection and preservation of species diversity insufficient step of vegetation restoration.  相似文献   

19.
TheSeslerio-Caricetum sempervirentis and theCaricetum ferrugineae from the Northern Calcareous Alps show considerable ecological and regional variation. 412 relevés representing both communities were classified by cluster analysis. Several subassociations and variants were distinguished and interpreted principally in terms of ecology and geographical distribution.  相似文献   

20.
The sedimentation of the Late Cretaceous Gosau Group of the Northern Calcareous Alps records the complex geodynamic evolution of the northern part of the Austroalpine microplate. The tectonically controlled sedimentation and facies distribution were mainly governed by the oblique subduction of the Pennic-Ligurian ocean below the Austroalpine margin. Most of the Gosau successions comprise two distinct sedimentary complexes. The Lower Gosau Subgroup (upper Turonian-Campanian) is characterized by terrestrial to shallow-marine facies associations: alluvial fan and fan delta deposits, shallow-marine sandstones and sandy limestones, and storm-influenced nearshore and shelf deposits. During the early Santonian sea-level highstand, a great part of the Northern Calcareous Alps was covered by a shallow shelf sea. Palaeotransport directions point to source areas situated both to the north and to the south of the Northern Calcareous Alps.

The Upper Gosau Subgroup (upper Santonian-Eocene) comprises deep-water hemipelagic and turbiditic deposits. Rapid subsidence into bathyal to abyssal depths started diachronously from the northwest (Santonian) to the southeast (Maastrichtian) after a short phase of deformation and erosion. Abyssal deposits in the northern parts of the Northern Calcareus Alps and north-directed palaeotransport indicate a tilting of the slope towards the north. This subsidence pulse is attributed to an event of subcrustal tectonic erosion, probably triggered by the subduction of a topographic high of the South Penninic ocean. The relationships of the Gosau Group of the Austroalpine unit to Late Cretaceous deposits of the Carpathians and Southern Alps are discussed in the framework of a plate tectonic model.  相似文献   


设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号