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Fragmentation impacts on tropical forests’ vegetation structure

Tropical forests are global epicentres of biodiversity and carbon storage. The provision of these planetary services by tropical forests is now highly threatened by anthropogenic activities, including deforestation, fragmentation and degradation (e.g. logging, fire).  However, there is still substantial uncertainty in the extent to which the planet’s tropical forests have been modified by human activity and the impacts of human activity to date on key forest services such as carbon storage. In particular, tropical forests vegetation are impacted by edge effects, either natural or more commonly  caused by logging and deforestation. Those edge effects can significantly affect the amount of carbon these stores [Brinck, 2017]. While these have been studied in case studies in multiple continents [Harper, 2005] there is still uncertainty as to the extent of edge effects across the whole pan-tropic region, with some papers proposing edge effects can reach several km into primary forest [Chaplin-Kramer, 2015].

This PhD project will utilize new space-borne LiDAR data coming from the GEDI mission to improve our understanding of anthropogenic controls of forest vegetation structure, in particular tree height, while accounting for other controlling factors such as water availability [Klein, 2015, Tao, 2016] and soil type [Gorgens, 2020]. GEDI produces a high-resolution laser ranging point observations of the 3D structure of the Earth, making precise measurements of forest canopy height, canopy vertical structure, and surface elevation. Deployed on the International Space Station (ISS) in 2018, GEDI started in March 2019 a two-year mission to collect forest data at a global scale. Combining GEDI with forest/non-forest land cover data derived from optical satellites (e.g Sentinel-2, Landsat-8) and auxiliary datasets on climate, soil, and topography will allow the first-ever pan-tropic statistical analysis of what controls tree height in different continents and biogeographical contexts at a pan-tropical scale. The potential of ESA BIOMASS P-band radar satellite (scheduled to be launched in Oct 2022) will be investigated.

The project will be co-supervised by Prof. Guy Ziv and Dr. David Galbraith (University of Leeds), Dr. Steven Hancock (University of Edinburgh) and Dr. Laura Duncanson, benefiting from their complementary expertise in Google Earth Engine (Ziv), forest ecology (Galbraith) and GEDI technology (Hancock, Duncanson). Carbomap will be an industrial partner in the project, providing a placement opportunity in Edinburgh during the project to expose the student to commercial applications of remote-sensing biomass monitoring. The student will also spend some time in NASA and/or the University of Maryland who developed and operates the GEDI mission. This studentship will be based at the School of Geography in the University of Leeds, within the vibrant cluster of Ecology and Global Change.

Brinck, K., Fischer, R., Groeneveld, J. et al. High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle. Nat Commun 8, 14855 (2017)

Harper, K.A., et al.  Edge influence on forest structure and composition in fragmented landscapes. Conservation Biology, 19,768–782 (2005)

Chaplin-Kramer, R., Ramler, I., Sharp, R. et al. Degradation in carbon stocks near tropical forest edges. Nat Commun 6, 10158 (2015).

Pan, Y. et al. A Large and Persistent Carbon Sink in the World’s Forests, Science 19, 988-993 (2011)

Klein, T., Randin, C. and Körner, C. (2015), Water availability predicts forest canopy height at the global scale. Ecol Lett, 18: 1311-1320. doi:10.1111/ele.12525

Tao, S., Guo, Q., Li, C., Wang, Z. and Fang, J. (2016), Global patterns and determinants of forest canopy height. Ecology, 97: 3265-3270. doi:10.1002/ecy.1580

Gorgens, E., Nunes, M. H., et al. Resource availability and disturbance shape maximum tree height across the Amazon, bioRxiv 2020.05.15.097683; doi: