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Land use change trends and Impact on Mountain Biodiversity: a global perspective Eva Spehn Global Mountain Biodiversity Assessment of DIVERSITAS Land use change & Mountain biodiversity Most wide spread utilization of mountain terrain: • Upland grazing, • often facilitated by fire management • often followed by erosion and enhanced risk for valley and foreland environments. Most land use changes reduce mountain biodiversity, especially: • Cultivation of formerly pristine areas • Intensification of agriculture/husbandry in montane areas • Abandonment of formerly grazed montane & alpine grasslands Biodiversity in the European Alps Intensification Two opposite trends: Abandonment Stöcklin J, Bosshard A, Klaus G, RudmannRudmann-Maurer K, Fischer M (2006) Land cover change -> consequences for biodiversity © Silvia Vananderoye Stöcklin J, Bosshard A, Klaus G, RudmannRudmann-Maurer K, Fischer M (2006) Land use change and mountain biodiversity Focus: (sub)tropical mountains • • • • 2 Workshops: Moshi,Tanzania 2002 & La Paz, Bolivia 2003 Research Agenda (2005) Synthesis book (2006) Network of field experiments 20052005- Financed by • Swiss Agency for Dev. and Cooperation SDC, • Food and Agricultural Organisation FAO • Swiss National Science Fondation GMBA Moshi-La Paz Research Agenda (2005) Providing priority research questions on land use effects on mountain biodiversity, specifically on : • The use of highland vegetation and husbandry systems (food) • Fire ecology • Highland cropping, hunting and gathering, and medicinal plants • Regeneration and re-vegetation outside forests • Upper montane forest and high elevation treelines (fiber and fuel) • Cross cutting research issues: Hydrology and erosion, interactions of land use with climate change, indigenous knowledge Land use change & Mountain biodiversity Synthesis book: Studies of fire and grazing effects on mountain biodiversity in: Andes (Argentina, Bolivia, Colombia, Peru, Venezuela) African Mountains (Tanzania, Uganda, Madagascar, South-Africa) Alps, Caucasus, Pamir, Himalaya, Snowy Mountains How does fire intensity or fire frequency in mountains affect biodiversity? Increase of Fire frequency at Kilimadjaro: from Podocarpus forest to Erica bushes: the loss of a life form (trees) (Hemp 2006, in Spehn, Liberman & Körner: Land use change and mountain biodiversity) Fire effects on mountain biodiversity: • Burnt areas are commonly poorer in species than unburnt areas (especially in uniform plots and if unburnt control contains forest) • Fire leads to degradation (e.g. of Paramo tussocks) if the regeneration takes longer than the burning frequency. • Woody components become eliminated or very uniform (Erica (Erica shrub in African mountains) • Moderate fires do not necessarily reduce plant cover and diversity, but induce a change in ecosystem functioning (e.g. Kilimanjaro: lost of cloud water trapping by destruction of Erica forest) How do changes in grazing regime in mountains affect biodiversity? • How does grazing and the pace of land use changes in mountains enhance or reduce biodiversity? Grazing effects on mountain biodiversity • Moderate grazing increases plant species diversity at local scale, as herbivory increases the competitive ability of other taxa ((Intermediate Intermediate disturbance hypothesis) hypothesis) • Grazing of high elevation grassland with a long history of ungulate presence commonly has little impact on biodiversity as long as stocking rates do not cause highly palatable species to disappear (Sarmiento et al; Bustamante et al; Rawat & Adhikari 2006, in Spehn, Liberman & Körner: Land use change and mountain biodiversity) Sustainable grazing management in subtropical highlands Appropriate stocking rates: • Best indicator is the abundance of lessless-palatable dominants vs. highlyhighly-palatable subdominants (robust vs. nutritious species) • Key role of marshmarsh-type meadows (dry parts of Inner Inner--Himalaya; bofedales in the Andes) during dry periods: their capacity determines the total stocking rate of a region. Appropriate animal selection: • “Picky animals” (cattle, sheep, alpaca) have much stronger impact on diversity and pasture quality than species with a broad food selection (e.g. llama). (Bustamante et al; Alzerreca et al., Molinillo & Monasterio 2006, in Spehn, Liberman & Körner: Land use change and mountain biodiversity) Interaction effects of fire and grazing on biodiversity Joint Research Projects established on Land use, mountain biodiversity and ecosystem services: services: European Alps (Switzerland, Austria, and France) Caucasus (Georgia) Andes (Altiplano/Bolivia) Himalayas (Tibet/China) www.gmba.unibas.ch