| 1. |
- Dengler, Jürgen, et al.
(författare)
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Working group on dry grasslands in the Nordic and Baltic region – Outline of the project and first results for the class Festuco-Brometea
- 2006
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Ingår i: Annali di Botanica N.S.. - 0365-0812. ; 6, s. 73-100
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Tidskriftsartikel (refereegranskat)abstract
- The vegetation databank established by our working group covers the classes Festuco-Brometea, Koelerio-Corynephoretea, and Trifolio-Geranietea sanguinei in the Nordic and Baltic region, i.e. NE Germany, Denmark, Norway, Sweden, Finland, N Poland, Lithuania, Latvia, Estonia, and NW Russia. We aim to use these data to develop a consistent supra-national phytosociological classification of these xerothermic vegetation types in the study area and to analyse their biodiversity patterns. Up to now, we located some 12,500 relevés meeting our criteria, and more than 3,500 of them have already been included in the databank. We give an overview of the properties of these relevés as regards coverage of syntaxa and countries, source types, plot sizes, and cryptogam treatment. We also present first analyses for the basiphilous semi-dry grasslands (Brachypodietalia pinnati) within the Festuco-Brometea. For this group of communities, many different and incompatible classification schemes have been proposed. We give an overview of the alliance and association names that have been in use for them in the study area, accompanied by a nomenclatural assessment. The relevés presently included in the databank have been tentatively assigned to those vegetation classes whose diagnostic taxa were prevailing. Accordingly, more than 2,000 relevés have been placed in the Festuco-Brometea. These show considerable floristic differences compared to stands of the southern temperate Brachypodietalia pinnati alliances Bromion erecti, Cirsio-Brachypodion pinnati, and Agrostion vinealis. The presence degrees of Avenula pratensis and Homalothecium lutescens, for instance, are significantly increased in the study area, and those of Festuca rupicola and Euphorbia cyparissias decreased. An analysis of the species-area relationship yielded a power function with z = 0.09 which is considerably lower than increments determined by nested-plot analyses of this commu-nity type, indicating the probable incompleteness of the species lists for many of the larger plots. Finally, we give an outlook on the future objectives of the working group.
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| 2. |
- Kuussaari, Mikko, et al.
(författare)
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Extinction debt: a challenge for biodiversity conservation
- 2009
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Ingår i: Trends in Ecology & Evolution. - : Elsevier BV. - 0169-5347 .- 1872-8383. ; 24:10, s. 564-571
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Tidskriftsartikel (refereegranskat)abstract
- Local extinction of species can occur with a substantial delay following habitat loss or degradation. Accumulating evidence suggests that such extinction debts pose a significant but often unrecognized challenge for biodiversity conservation across a wide range of taxa and ecosystems. Species with long generation times and populations near their extinction threshold are most likely to have an extinction debt. However, as long as a species that is predicted to become extinct still persists, there is time for conservation measures such as habitat restoration and landscape management. Standardized long-term monitoring, more high-quality empirical studies on different taxa and ecosystems and further development of analytical methods will help to better quantify extinction debt and protect biodiversity.
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| 3. |
- Pärtel, Meelis, et al.
(författare)
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Biodiversity in temperate European grasslands: origin and conservation.
- 2005
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Ingår i: Grassland Science in Europe. - 9985961137 ; 10, s. 1-14
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Northern Europe is in the forest zone, but wild megaherbivores have maintained grass-dominated vegetation here for the last 1.8 million years. Continuity of the grassland biome through glacialinterglacial cycles and connection to steppe vegetation has resulted in the evolution, immigration, and survival of a large number of grassland species. During the last millennia the effect of wild ungulates has been replaced by domestic grazers and hay making, and the persistence of grassland biodiversity depends on livestock farming. Local diversity is the outcome of colonisations and extinctions. Colonisations can be enhanced by maintaining networks of grasslands where species can migrate between sites, and by proper management that promotes establishment of new individuals. Extinction risk may be lowered in large grasslands, which may support large populations, and by proper management that promotes coexistence of species. Extinctions are accelerated by changes in environmental conditions favouring a few competitively superior plant species, especially increase in soil fertility. During the last century, natural grasslands in Europe have faced a dramatic loss of area and increased isolation of the remaining fragments, cessation of proper management, and increased load of nutrients. To achieve successful grassland biodiversity conservation there needs to be close cooperation between conservation managers and livestock farmers. For that, grassland management should take into account evolutionary and ecological rules behind the grassland biodiversity.
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