Currently, there are substantial threats to ecosystems mainly from overgrazing by goats and sheep… read more
With this working package, the spatial and demographic structure of Quercus petrea forests are characterised using the method of Citizen science. Particular emphasis is given to forest regeneration processes as critical process in forest dynamics. A lack in tree regeneration for prolonged periods because of intensive herbivory can drive forests beyond tipping points once the mature forest dies from disturbances or senescence. The forest structure reflects the islands land use history. Nearly no seedlings and the high density of pasture tracks are evidence for excessive grazing pressure.
On the state of oak forests
The study aimed to create a scientific basis for the restoration of the remaining Quercus petraea forests through the characterization of the spatial and demographic structure and the identification of areas for restoration.
Samothraki has a long history of pastoral and silvo-pastoral land use. Currently, there are substantial threats to ecosystems mainly from overgrazing by goats and sheep. With this master thesis, the spatial and demographic structure of Quercus petrea forests were characterised.
Particular emphasis was given to forest regeneration processes as critical process in forest dynamics. A lack of tree regeneration for prolonged periods because of intensive herbivory can drive forests beyond tipping points once the mature forest dies from disturbances or senescence. This is particularly true for Mediterranean forests. Assessing tree regeneration thus addresses a crucial indicator for future forest development.
The forest structure reflected the land use of the last years in the study area. Nearly no seedlings and the high density of pasture tracks were evidence of excessive grazing pressure. The results showed a mainly low stocked and over-aged oak woodland with many already declining trees.
Regions with especially high restoration priority were found on 85,9% of the total study area. Mainly the forest close to Ano Meria and parts of the Martini Forest, especially the higher altitudes, are endangered. Forest restoration therefore is important to restore the sustainability of the ecosystem and the ability to face challenges of future conditions like warmer and drier periods through climate change.
The second aim was to raise awareness about the importance of the forest as part of the valuable heritage of the island with its ability to reflect the island’s history in its growth pattern. The involvement of residents of the island in the research through the citizen science project was an important step towards achieving this.
The forest structure revealed past silvo-pastoral systems and reflected the impact of the massacre in 1821. The lack of animals on the island in the following years allowed tree regeneration. This highlights again the influence of the livestock on the regeneration possibilities on the island.
The growth pattern found also reflected important socio-economic changes. A time of intensive cultivation and flourishing in the 18th century could be detected and the start of an important economic period, the charcoal production for export in the 19th century, was clearly visible.
Still there needs to be more research for the successful implementation of a restoration project. Especially the regeneration ecology has to be investigated more closely. The identification of regeneration niches and the analysis of seed production, – predation and – viability, are crucial for effective regeneration efforts.