Mammals and birds depend highly on the existence of green structures for foraging and nesting. Some species prefer dense forests while others use solitary trees or bushes. For this thesis topic the aim is to derive green landscape structures from the AHN3 pointcloud that are relevant for birds and, particularly, the European turtle dove.
ALS | Airborne Lidar Scanning data (ALS) provides height information in XYZ points. ALS is commonly used to derive digital elevation models for large area and extract other derivatives from height information about objects. Well-known examples are digital terrain and surface modelling, hydrological derivatives or modelling and adding the third dimension (z) to geo-visualizations. ALS is also useful for modelling vegetation, for example in forest management, crop monitoring or 3D representations of urban green.
AHN | The Algemeen Hoogtebestand Nederland (AHN) is an ALS dataset that covers the whole of the Netherlands and was used primarily for national water management. In 2014 the AHN became publicly available, free of charge, and is widely used in 3D modelling of buildings and other physical objects in the Netherlands. The benefit of the AHN dataset is the large spatial coverage of the ALS. On the other hand, one of the major drawbacks and challenges of the AHN ALS data is the relatively limited point density (10-20 pts/m2). This raises the question what the potential of the AHN is in the Netherlands, and to what extent this dataset can be used for representing and modelling the world around us.
European Turtle Dove | The European turtle dove (Dutch: zomertortel) is the Netherlands’ smallest dove species, and the only one that migrates to Africa every winter. Over the last decades their population has been rapidly declining, and it now has the IUCN-status ‘Vulnerable’. Several reasons are likely causing the extinction of the bird, including the decline in landscape variation and small-scale vegetation structures in rural areas due to the upscaling of farming parcels in its breeding areas. In Zeeland, researchers and volunteers have been studying the turtle dove since 2018 and are exploring potential solutions to increase the survival rates of the species during the breeding season (May to September). They are interested in identifying what factors influence the foraging habitat choice and small-scale landscape use of turtle doves. The importance of different landscape features needs to be investigated by experts but will include the identification of (for example) stand-alone trees, tree lines, scrub, hedges, forest edges, farmyards and orchards.
Doves are known to value overgrown hedges and scrub, and trees with more open canopies. Finding ways to quantify and measure existing green landscape structures in the Netherlands and, in particular, Walcheren, Zeeland would greatly help researchers to assess their use by, and value to, turtle doves. If successful, it could also help assess and predict landscape suitability in other areas of the Netherlands.
Exact Research Objectives will be formulated with supervisor, but potential objectives are:
- Review literature on methods to derive green landscape structures based on ALS.
- Inspect quality and suitability of the AHN to represent green landscape structures for the European turtle dove.
- Develop a method to derive green landscape structures relevant for the European turtle dove based on the AHN data source.
- Apply on Walcheren, Zeeland & evaluate the accuracy of results
- Due to the relatively large file sizes (point clouds) the methods for this thesis research must be implemented in a scripting language like Python or R. Therefore, basic scripting skills (e.g. python or R) are required, as is the curiosity and willingness to learn/invest more in (geo)scripting skills.
- Some love and passion for ecology and especially the European turtle dove
Theme(s): Modelling & visualisation; Integrated Land Monitoring