Forage quality as a limiting factor for cattle grazing in isolated Dutch nature reserves

Selected abstracts servation potential of individual woods so that informed decisions can be made on management requirements. Examples of positive management are: developing varied age cJass and structure; introducing characteristicplants and animals; retaining trees to biological maturity and beyond; leaving dead standing and fallen trees and wood. -from Authors 93Z/00032 The influence of r i p a r i a n management on the habitat structure and m a c r o i n v e r t e b r a t e communities of upland streams draining plantation forests S. J. Ormerod, S. D. Rundle, E. C. Lloyd & A. A. Douglas, Journal of Applied Ecology, 30(1), 1993, pp 13-24. Habitat features and macroinvertebrate communities were surveyed in 66 predominantly upland streams throughout Wales and Scotland to assess the efficacy of riparian management (as buffer strips) in protecting stream resources during commercial forestry. Marginal habitat characteristics differed between streams with different riparian management. Streams with 'harder' margins occurred where the banks were covered with either conifers or broadleaves. Streams with 'softer' margins occurred in seminatural moorland, and where a buffer strip of moorland vegetation had been retained along the stream at the planting stage. Streams in conifer forest in which a riparian buffer strip had been cleared retrospectively were intermediate. For any given pH, aluminium concentrations were significantly higher in streams draining conifer catchments than in streams draining whole catchments of moorland or deciduous woodland. The taxon richnesses of Ephemeroptera, Plecoptera, Trichoptera and all taxa combined, in both riffles and margins, declined significantly with increasing acidity and aluminium concentration. Primary ordination axes form both habitats correlated with taxon richness, and hence also with pH and aluminium. However, there were significant effects on the ordination scores by riparian management, due mostly to reduced taxon richnesses in conifer sites without buffer strips. -from Authors 93Z/00033 The c u r r e n t status and plant ecology of disused railway lines in North Tyneside D. N. Mitchell & J. A. Cooke, Transactions - Natural History Society of Northumbria, 55(4), 1991, pp 273-282. Six main types of habitat on these abandoned lines are identified and characteristic species associated with each habitat are described. Particularly important areas which possess locally rare plant species are also described. A series of objectives for the future conservation management of this linear resource includes the control of future coal reclamation schemes and the protection of those sections of line with locally rare plants. -from Authors 93Z/00034 Lovtakt - en viktig faktor i formandet av Alands g r a s s v a l a r (Leaf harvesting - an important factor for the formulation of semi-natural grassland in Aland, Finland) H. Slotte, Svensk Botanisk Tidskrift, 86(2), 1992, pp 63-75. Human activity and domestic animals have kept old natural plant communities in existence after the extinction of big nerbivores; leaf harvest may have had an important role here. Conservationists should give more attentxon to deciduous woods and past meadow areas and more often introduce leaf harvesting and grazing in schedules for management of nature reserves. -from English summary 93Z/00035 F o r a g e quality as a limiting factor for cattle grazing in isolated Dutch nature reserves J. Bokdam & M. F. Wallis de Vries, Conservation Biology, 6(3), 1992, pp 399-408. Most Dutch nature reserves are small, isolated fragments of former semi-natural landscapes. Cattle and other large domestic herbivores are being increasingly (re)introduced m nature reserves as a tool for vegetation management and as an ecological substitute for extinct wild herbivores. The performance of cattle appears to be seriously limited by a combination of inadequate forage and habitat isolation. In landscapes of low fertility, insufficient concentrations were found of P, Na, Ca, and Mg. In landscapes of intermediate

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fertility, the level of Na is deficient for most of the year. Winter digestibility is inadequate in vegetation remaining ungrazed until winter, whereas in grazed vegetation me quantity of easily.digestible forage is insufficient to satisfy quantitative intake requirements. In landscapes of high fertility, the mineral supply is adequate, but low digestibility in winter will lead to energy shortage. Insufficient forage quality seems to preclude sustained year-round grazing in each of the three landscape types. Single-landscape areas constitute seasonal habitats for cattle, suitable for summer or winter grazing only. Connection of complementary landscapes is essential to create complete year-round habitats for cattle and other large berblvores. Restoration of linkage of summer and winter range by the creation of corridors is the most natural solution. -from Authors 93Z/00036 Quelques reflexions a propos de l'endemisme insulaire (La Corse). Methodes de travail (Reflections on island endemism in Corsica. Methodologies) J. Contandriopoulos, Polish Botanical Studies, 2, 1991, pp 39-59. Taking into acocunt recent threats concerning the environment, some measures towards the protection of endemic flora are considered. -from English summary 93Z/00037 Threats to the natural environment in the Polish Tatra Mountains Z. Mixek, Mountain Research & Development, 12(2), 1992, pp 193-203. The Tatra Mountains have become one of the most endangered areas of Poland through recent and past anthropogenic pressure. The natural vegetation has been degraded and many indigenous species have been replaced by introduced plants. Some mammal populations are threatened, certain butterfly species face extinction, and eutrophication of mountain lakes has many detrimental consequences. -Author 93Z/00038 Effects of recreational scuba diving on coral reefs: trampling on reef-fiat communities J. P. Hawkins & C. M. Roberts, Journal of Applied Ecology, 30(1), 1993, pp 25-30. Near Sharm-el-Sheikh, a popular Red Sea resort in Egypt, there were significantly more damaged coral colonies and loose fragments of live coral in heavily-trampled than in little-trampled areas. Percentage cover of bare rock and rubble was also significantly greater; conversely, numbers of hard coral colonies and total percentage live coral cover were lower. Coral colonies were smaller in trampled compared to control areas, with average height a n d diameter significantly less in heavily-trampled areas. Coral species composition and the relative abundances of different coral growth forms did not appear to be affected by trampling. -from Authors 93Z/00039

Rates and patterns of deforestation in the information sys-

Philippines:applicationof geographic

tem analysis D.S. Lui, L. R. Iverson & S. Brown, Forest Ecology & Management, 57(1-4), 1993, pp 1-16. The Philippines lost a totalof 9.8 million ha of forests from 1934-1988. The closer a forestwas to roads, the higher the rate of deforestation.The large the perimeter-to-area (P/A) ratio of a forestpatch, the more likelyitwas to be cleared. Forests with P/A ratios greater than 65 m ha -t in 1934 had all disappeared by 1988. Forests with large P/A ratios were also characterized by small area and the presence of adjacent agricultural lands in 1934. They were readily cleared and never reforested. -from Authors