Land abandonment and vegetation change in open landscapes: assessing biodiversity impacts and options for mitigation
Abandon et changement de la végétation dans les espaces naturels ouverts: impacts sur la biodiversité et options de remédiation
Résumé
The aims of this study are to determine, for different habitats, the impacts of land abandonment and woody colonisation on plant richness and composition, number of protected species and main plant traits. Succession in this study was analyzed in 6 habitats in Europe - heathlands, mid-elevation grasslands, coastal dune grasslands, calcareous grasslands, alpine grasslands and arable fields - using long-term permanent plots or chronosequences. Results showed that abandonment and woody colonisation were associated with profound changes in floristic composition but contrasted responses as regards total species richness. Protected species were less numerous in later stages for semi-natural habitats but weakly increased in arable fields. Ellenberg values indicated environmental conditions changes, in particular a decrease of light availability in all habitats and an increase in soil nitrogen in semi-natural habitats but a decrease in arable fields. Increasing abundance of competitive species and decreasing abundance of ruderal species with succession were recorded. Life form, reproduction, leaf persistence and anatomy, plant morphology and pollination dispersal also changed with succession. Lastly, some implications for management of habitats at risk of abandonment and woody colonisation are discussed.