Secondary forests that regrow after agricultural land has been abandoned now comprise more than half of the forest area worldwide, and particularly in the Tropics land-use change occurs rapidly. It is essential to understand to what extent secondary forests can provide the same ecosystem services as primary, undisturbed forests. Generally, secondary forests recover quickly the biomass and species richness of primary forests (Martin et al. 2013, Poorter et al. 2016), but how previous land-use intensity and forest configuration in the landscape matrix influence the rate of recovery remains poorly understood.
The intensity, and duration, of land use prior to abandonment influences to what extent forest legacies like a soil seed bank, tree stumps and roots that can resprout, and remnant forest trees are present, and can speed up forest regrowth. The amount, and configuration, of forest cover in the landscape also influences recovery rates. Forest patches nearby provide tree seed sources and attract dispersers, and can thereby increase recovery rates of forest carbon stocks and species richness (Guariguata and Ostertag 2001).
So far, effects of previous land use have mostly been assessed in broad land-use type classes, and effects of forest configuration in the landscape have been assessed at just one point in time. In this project, you will use time series of medium-resolution satellite images (i.e. Landsat, Sentinel-2) to quantify (1) the duration of previous land-use by analysing when forest was lost and growing back in the past, and (2) the configuration of forest patches in the landscape matrix, and temporal changes therein, for secondary tropical forests in Mexico. You will assess how land-use history and the landscape matrix influence recovery of biomass and species richness using field data from secondary forest plots.
The following R packages and tutorials are available for getting started with forest change analysis:
- Quantifying land-use history and the configuration of forest patches in the landscape from Landsat time series
- Assessing how land-use intensity and the landscape matrix influence recovery of biomass and biodiversity in secondary forests in Mexico
- Guariguata MR, Ostertag R (2001) Neotropical secondary forest succession: changes in structural and functional characteristics. For. Ecol. Manage. 148:185-206.
- Martin PA, Newton AC, Bullock JM (2013) Carbon pools recover more quickly than plant biodiversity in tropical secondary forests. Proc. R. Soc. B 280.
- Poorter L et al. (2016) Biomass resilience of Neotropical secondary forests. Nature 530:211-214.
- Dutrieux LP, Jakovac CC, Latifah SH, Kooistra L (2016) Reconstructing land use history from Landsat time-series: Case study of a swidden agriculture system in Brazil. Int. J. Appl. Earth Obs. Geoinf. 47:112–124.
- Advanced Earth observation course
- Geo-scripting course: Scripting skills (R and/or Python) for handling spatial data
- Analytical skills
Theme(s): Sensing & measuring, Modelling & visualisation