Global-scale mapping of changes in ecosystem functioning from earth observation-based trends in total and recurrent vegetation

Research output: Contribution to journalArticle

Abstract

Aim: To evaluate trend analysis of earth observation (EO) dense time series as a new way of describing and mapping changes in ecosystem functioning at regional to global scales. Spatio-temporal patterns of change covering 1982-2011 are discussed in the context of changes in land use and land cover (LULCC). Location: Global. Methods: This study takes advantage of the different phenological cycles of recurrent vegetation (herbaceous vegetation) and persistent vegetation (woody/shrub cover) in combining trend analyses of global-scale vegetation based on different annual/seasonal normalized difference vegetation index (NDVI) metrics. Spatial patterns of combined vegetation trends derived from the Global Inventory Modeling and Mapping Studies NDVI are analysed using land-cover information (GLC2000). Results: The direction of change in annual and seasonal NDVI metrics is similar for most global terrestrial ecosystems, but areas of diverging trends were also observed for certain regions across the globe. These areas are shown to be dominated by land-cover classes of deciduous forest in tropical/subtropical areas. Areas of observed change are found in dry deciduous forest in South America and central southern Africa and are in accordance with studies of hotspot LULCC areas conducted at local and regional scales. The results show that dense time series of EO data can be used to map large-scale changes in ecosystem functional type that are due to forest cover dynamics, including forest degradation, deforestation/reforestation and bush encroachment. Main conclusions: We show that areas characterized by changes in ecosystem functioning governed by LULCC at regional and global scales can be mapped from dense time series of global EO data. The patterns of diverging NDVI metric trends can be used as a reference in evaluating the impacts of environmental changes related to LULCC and the approach may be used to detect changes in ecosystem functioning over time.

Details

Authors
  • Rasmus Fensholt
  • Stéphanie Horion
  • Torbern Tagesson
  • Andrea Ehammer
  • Eva Ivits
  • Kjeld Rasmussen
External organisations
  • University of Copenhagen
  • European Environment Agency (EEA)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Geography

Keywords

  • Ecosystem functioning change, Land-use land-cover change (LULCC), Phenology, Remote sensing, Trend analysis, Vegetation greenness
Original languageEnglish
Pages (from-to)1003-1017
Number of pages15
JournalGlobal Ecology and Biogeography
Volume24
Issue number9
Publication statusPublished - 2015 Jan 1
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes

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