Onderwerp scriptie

MSc Thesis topic: Investigating changes in the dryland ecosystems over the last 40 years and its causes

Being one of the largest ecosystems of the Earth, drylands are home to many flora and fauna in addition to supporting the livelihoods of millions of people for their food security and wellbeing. At the same time, these areas are highly susceptible to be affected by climate change and human activities. As a result, significant parts of drylands are reported to be affected by land degradation and desertification. Monitoring the long-term changes in the dryland ecosystem and understanding their causes can bring light to decision-making and mitigation efforts to end desertification and support effective restoration.

Long-term time series analaysis can be conducted on historical data (e.g., soil and vegetation characteristics) to identify gradual and abrubt changes. Such changes in vegetation and soil characterisitcs in dryland areas can further be related to land use change, e.g. pasture management (utilization and intensity) and climate change to understand the impact of human activity and climate on dryland ecosystems.

This research topic aims to analyze and identify abrupt changes (turning points) in environmental variables such as vegetation and soil, in a dryland region of Central Asia (Mongolia). Ultimatly it will investigate  possible links between these observed changes and  changes in land use (intensity) and climate variables . The research will focus on time-series analyses of long-term satellite data (for 40 years) at regional to national scales in combination with spatial data analyses of land use intensity.

Objectives

  • Investigate data availability on possible indicator on rangeland ecosystem (e.g., vegetation, soil and climate)
  • To analyse and identify turning points in dryland ecosystem using 40 years of time series remote sensing data
  • To investigate temporal relation between land use intensity (pastoral area utilization and intensity), environmental and climate variables

Literature

  • Fensholt et al 2015 “Assessment of Vegetation Trends in Drylands from Time Series of Earth Observation Data” in Remote Sensing Time Series, DOI: 10.1007/978-3-319-15967-6_8
  • Horion S, Prishchepov A V., Verbesselt J, de Beurs K, Tagesson T, Fensholt R (2016) Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier. Global change biology, 22, 2801–2817
  • de Jong R, Verbesselt J, Zeileis A, Schaepman ME (2013) Shifts in global vegetation activity trends. Remote Sensing, 5, 1117–1133.
  • de Jong R, Verbesselt J, Schaepman ME, de Bruin S (2012) Trend changes in global greening and browning: Contribution of short-term trends to longer-term change. Global Change Biology, 18, 642–655.
  • https://www.sciencedirect.com/science/article/pii/S1574954114001551?via%3Dihub
  • http://climate.calcommons.org/variable/climatic-water-deficit

Requirements

  • Advanced Earth Observation course
  • Good knowledge in scripting is an asset (e.g. R, Google Earth Engine)
  • Analytical skills

Theme(s): Integrated Land Monitoring; Human – space interaction