Title: Palaearctic grasslands in transition : overarching patterns and future prospects
Authors : Török, Péter
Dengler, Jürgen
Published in : Grasslands of the world: diversity, management and conservation
Editors of the parent work: Squires, Victor R.
Dengler, Jürgen
Feng, Haiying
Limin, Hua
Publisher / Ed. Institution : CRC Press
Publisher / Ed. Institution: Boca Raton, US
Issue Date: 2018
Language : Englisch / English
Subjects : Grassland; Conservation
Subject (DDC) : 577: Ökologie
Abstract: The Palaearctic biogeographic realm extends over some 45 million km² and thus more than 1/3 of the terrestrial ice-free surface on Earth. It comprises extensive grasslands of different types and origin, which can be subdivided into (1) natural grasslands with (1a) steppes (climatogenic in dry climates), (1b) arctic-alpine grasslands (climatogenic in cold climates) and (1c) azonal and extrazonal grasslands (pedogenic and topogenic) as well as (2) secondary grasslands created and sustained by human activities, such as livestock grazing, mowing or burning. Grasslands of the Palaearctic do not only form a major basis for the agriculture of the region and thus its food supply, but are also crucial for other ecosystem services and host a supraproportional part the realm’s plant and animal diversity. To reflect that suitability of grasslands for biodiversity strongly depends on their state, we apply the term High Nature Value (HNV) grassland to those natural grasslands that are not degraded (we call them in good state) and those secondary grasslands that are not intensified (we call them semi-natural). The synthesis at hand introduces seven comprehensive regional chapters organized by the Eurasian Dry Grassland Group (EDGG) on diversity, management and conservation of grasslands of the Palaearctic, covering nearly the complete extent of this realm. After introducing the EDGG as a leading international network dealing with these topics, we take advantage of the information compiled in the regional chapters and the expertise present among their 28 authors from 17 different countries to compile for the first time statistics on grassland types and areas as well as rankings of relative importance of factors reducing their biodiversity for the whole Palaearctic biogeographic realm and its major subdivisions (Western and Northern Europe; Eastern Europe; Mediterranean Basin and the Middle East; Russia; Kazakhstan and Middle Asia; China and Mongolia; Japan). We conclude that the current grassland area in the realm is about 9.7 million km²of which ca. 78% are natural (45% steppes, 29% arctic-alpine grasslands, 4% azonal/extrazonal grasslands) and 22% secondary. The remaining natural grasslands overall represent about 72% of their original extent, but only 7% in Eastern Europe. Among the extant grasslands about 4/5 are of High Nature Value, with the highest fraction in the interior of the Eurasian continent and lowest values at its margins, namely Western Europe and Japan. Among the threat factors, abandonment or underuse were most important in general. Only in Russia, Kazakhstan and Middle Asia conversion of grasslands to arable lands was ranked first among the factors, as was eutrophication in Western and Northern Europe. Our area statistics and ranking of threat factors for a complete vegetation formation across the biogeographic realm are important pieces of information both for conservation and basic research – despite all their current limitations. In conclusion, Palaearctic grasslands are in very intense transition; in most regions grassland biodiversity is facing many threats that are strongly linked to changes in human activities. For sustainable use and biodiversity conservation, an integrative view and holistic thinking are inevitable.
Departement: Life Sciences und Facility Management
Organisational Unit: Institut für Umwelt und Natürliche Ressourcen (IUNR)
Publication type: Buchbeitrag / Book Part
ISBN: 9781498796262
URI: https://digitalcollection.zhaw.ch/handle/11475/1498
Appears in Collections:Publikationen Life Sciences und Facility Management

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