Environmental hydro-refugia demonstrated by vegetation vigour in the Okavango Delta, Botswana

Sally C Reynolds, Christopher G Marston, Hossein Hassani, Geoff C P King, Matthew R Bennett

Research output: Contribution to journalArticle

5 Citations (Scopus)
88 Downloads (Pure)

Abstract

Climate shifts at decadal scales can have environmental consequences, and therefore, identifying areas that act as environmental refugia is valuable in understanding future climate variability. Here we illustrate how, given appropriate geohydrology, a rift basin and its catchment can buffer vegetation response to climate signals on decadal time-scales, therefore exerting strong local environmental control. We use time-series data derived from Normalised Difference Vegetation Index (NDVI) residuals that record vegetation vigour, extracted from a decadal span of MODIS images, to demonstrate hydrogeological buffering. While this has been described previously it has never been demonstrated via remote sensing and results in relative stability in vegetation vigour inside the delta, compared to that outside. As such the Delta acts as a regional hydro-refugium. This provides insight, not only to the potential impact of future climate in the region, but also demonstrates why similar basins are attractive to fauna, including our ancestors, in regions like eastern Africa. Although vertebrate evolution operates on time scales longer than decades, the sensitivity of rift wetlands to climate change has been stressed by some authors, and this work demonstrates another example of the unique properties that such basins can afford, given the right hydrological conditions.
Original languageEnglish
Pages (from-to)35951
JournalScientific Reports
Volume6
Early online date24 Oct 2016
DOIs
Publication statusE-pub ahead of print - 24 Oct 2016

Keywords

  • Palaeontology
  • tectonics
  • wetlands ecology
  • remote sensing
  • time-series
  • NDVI
  • Okavango
  • MODIS

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