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Middle East Technical University (2012)

Factors affecting steppe biodiversity in central part of the Anatolian diagonal and their use in conservation

Ambarlı, Didem.

Titre : Factors affecting steppe biodiversity in central part of the Anatolian diagonal and their use in conservation

Auteur : Ambarlı, Didem.

Université de soutenance : Middle East Technical University

Grade : Doctor of Philosophy (PhD) 2012

Résumé
This study aims to find out major factors acting on steppe biodiversity of Inner Anatolia by focusing on one million hectares of mountainous land. Quantitative data on common plants, breeding birds and butterflies as well as environmental and land use data were collected at 33 sites determined by environmental stratification. Data has been analyzed with Spearman’s rank correlation, canonical correspondence analysis, detrended correspondence analysis, two-way indicator species analysis and hierarchical partitioning. Results show that elevation, current grazing intensity, distance to woodlands and arable lands are the main determinants of richness and diversity. Other important factors are soil Magnesium and organic matter for plants ; local heterogeneity and shrub/tree density for birds ; plant richness and mud-puddling sites or wind shelters attracting butterflies. Altitude and grazing intensity have negative effects on biodiversity whereas soil Magnesium and proximity to other vegetation types have positive effects. In sites with more than 90% herbaceous coverage, shrub/tree density is a good indicator for the richness patterns of all groups. The richest sites are low mountain shrubby steppes close to woodlands and arable lands, ploughed 30-100 years ago but then abandoned and experienced light or no grazing afterwards. Six major plant communities are distinguished by gypsum bedrock, altitude and years since land abandonment. Four main bird assemblages are differentiated with landscape and local heterogeneity and composition and wood density of the sites. Various factors act on richness and diversity patterns on steppes, differing for species groups and assemblages. Conservation actions should encompass conservation priority species, represent different species assemblages, consider all major factors mentioned above especially landscape and local heterogeneity including different seral stages and sustaining conservation through nature-friendly land use. Planning afforestation in the way not to destroy rich steppes and building awareness on steppes as a value are important conservation actions.

Mots clés : Steppe, Biodiversity, Land use, Environmental parameters, Multivariate techniques.

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