摘要:

The fossil record shows thatPteridiumhas been present in all the temperate stages of the Quaternary, but that for most of this period it formed a component of the herb layer of deciduous woodlands. Bracken did not begin to reach its present abundance and importance until widespread forest clearance began with the arrival of Neolithic man about 5000 years ago. Some of the factors that have played a role in the history of bracken are illustrated by a discussion of the spread of bracken in Scotland that occurred contemporaneously with the change from cattle‐ to sheep‐farming in the 18th century. It is shown that man has played a dominant role in influencing the spread of bracken in Scotland, but that bracken was considered of great positive economic value. The ethnobotany of bracken is discussed, and it is suggested that it was once an important source of potash for the glass, soap and bleaching industries. The use of the plant as fuel, thatch, litter, compost and food, and for medicinal purposes is considered, and mention is made of various minor uses of the plant. Unfortunately it is difficult to estimate the amount of bracken consumed by these various employments, but it is suggested that the increased abundance of the plant may have been exaggerated because what was once a useful resource has now become a p

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02020.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Recent excavations at Vindolanda have disclosed that the floors of pre‐Hadrianic buildings were mainly composed ofPteridium, with considerable quantities of straw, several species of trees, and some bryophytes, notablyHylocomium splendens.The thickness of the bracken deposits suggests that bracken‐harvesting was a major occupation of the community, which may have used it for winter bedding. Conditions apparently were very insanitary as the ‘bedding’ of a 30 m2area contained 1/4 million puparia of the stable‐fly (Stomoxys calcitrans). The bracken deposits were encapsulated between layers of clay in anaerobic but not, as far as is known, water‐logged conditions, and together with urine impregnation provide a remarkable medium for the preservation of natural and man‐made materials, including a unique collection of writing tablets which give information about Roman Britain

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02021.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The species of herbivorous arthropods known to feed on bracken in Britain are listed and the seasonal changes in the structure of this arthropod community are discussed.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02022.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Information about the morphology of bracken (Pteridium aquilinum(L.) Kuhn var.aquilinum) and the chief nutrients in the frond at different times of the year introduce an account of litter production and its accumulation in relation to the behaviour of frond, root and rhizome systems.Where litter gain exceeds loss there is a correlation between the thickness and/or kind of litter and the level of the root and rhizome systems in relation to the mineral soil surface: with increase of litter the bracken becomes progressively more dependent for its physical and chemical soil environment on its own débris and less on the underlying mineral soil. An example of the limit of complete dependence has not been examined, but degeneration of the community can take place before that stage is reached.From a review of the chief factors affecting bracken the conclusion is reached that the woodland habitat is both favourable and restrictive: in it bracken is in equilibrium with its environment, at a high social status. The relationship with other plant communities depends largely on the degree of human interference to which each is subject. Dominant bracken when left alone, and where gain of litter exceeds loss, becomes the victim of its own success; local degeneration opens the way for entry by other species

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02023.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Mechanical methods of bracken control are now being replaced by the use of chemicals. Trials indicate the value of asulam and glyphosate in reducing frond numbers of bracken when sprayed in late July or early August in the west of Scotland. There is still a need to find a bracken eradicant chemical rather than a control chemical. Research is also required to investigate the results of removing the bracken cover on the ecology of the treated areas. The effects of sudden exposure of the hitherto protected grass to extremes of climate are not known.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02024.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Foliage‐application of 4.4 kg/ha asulam [methyl (4‐aminobenzenesulphonyl) carbamate] to field bracken reduced frond density by 97.1, 87.6 and 77.8%, one, two and three years respectively, after treatment. Examination of the rhizome system from these plots revealed that a high proportion of the rhizome apices and frond buds were killed, the remainder being damaged or remaining dormant. Autoradiography of bracken plants grown from sporelings or fragments and treated with14C‐ring‐labelled asulam revealed that uptake was rapid and progressive with time, whilst translocation was generally basipetal showing a typical source‐sink pattern, with intense accumulation in the apices and buds. Optimum penetration and basipetal translocation was achieved when treatments were applied to almost fully‐expanded fronds; application to immature fronds resulted in predominantly acropetal movement. Basipetal translocation was extensive in field bracken, accumulation occurring in the buds distant from the base of the treated fronds. There was evidence that asulam was relatively persistent in the rhizome system, 59 and 8% of the applied activity remaining in the rhizome, one and ten months respectively, after treatment. Hydrolysis of asulam produced small amounts of sulphanilamide (<10%) and traces of sulphanilic acid, 4‐aminophenol and benzene sulphonamide. Studies on the effect of asulam on the incorporation of14C‐labelled precursors into RNA and protein indicate that inhibition of RNA and protein syntheses may be major sites of a

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02025.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The importance of considering bracken as part of a dynamic soil/plant/animal system is emphasized and the extent, distribution and successional relationships of the fern in the uplands are discussed. Pteridietum is classified into six types according to its pattern of local distribution. Bracken communities as animal habitat are considered in relation to distribution types, frond density and canopy cover. As a direct source of food for the vertebrates bracken is considered to be of little or no value. As an indirect source of food bracken communities may be important in providing habitats for invertebrates, though in terms of numbers of species the insect fauna of vigorous Pteridietum is not great compared with that of other communities that may replace it. Pteridietum provides shelter and cover for a number of small mammals but in these respects it is of very limited value to the larger grazing animals. It is estimated that in Scotland, under the economic conditions of recent years, bracken herbicide is unlikely to be used on more than about 40,470 ha (100,000 acres) in the combined land uses of agriculture, forestry and sport; i.e. less than 25% of the Scottish bracken coverage is at risk. At this level of control, provided some precautions are taken, it is considered that the wild vertebrates are unlikely to be seriously affected; indeed in certain situations some benefits may be derived.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02026.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

In addition to bracken,Pteridium aquilinum, and other ferns, only a restricted range of species among the natural flora suffer severe damage if sprayed with asulam in late summer. Of the plants associated with bracken in relatively well‐drained situations those affected most by the herbicide include the threeUlexspecies,Rumex acetosella, young plants ofCalluna vulgaris, some Compositae and grasses of the generaPoa, HolcusandAgrostis(though notA. setacea). In damp and wet upland habitats,Cirsium palustre, Juncus effusus, Glyceria fluitansand a few other species are moderately susceptible to asulam but the majority of plants appear to be resistant or only slightly damaged.Areas from which bracken has largely been removed tend to be invaded by such species asDeschampsia flexuosa, Holcus mollis, Chamaenerion augustifolium, Digitalis purpureaandUrtica dioica. If grazing pressure is low the absence of competition enables woody species to regenerate from seed. Colonization and subsequent spread of the perennial plants is influenced by what was present as ground flora before the bracken was killed and by the depth of bracken litter.Asulam is considered to be a useful aid to the management of nature reserves where encroachment by bracken needs to be checked. Its most widespread use for bracken control is likely to be on upland farms to clear bracken from marginal land with the aim of increasing and improving pasture. Adjoining woodland and moorland habitats may suffer from resulting changes in land management. Moreover, indiscriminate aerial spraying of asulam over large areas may affect local populations of plants, notably ferns, in the more open areas not protected by a canopy of bracke

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02027.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02027a.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1976.tb02010a.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY