@phdthesis{01HBR5QBZ1YCK0QCNJX8EG7G72,
  abstract     = {{Forest ecosystems buffer climate extremes and mitigate climate change effects 
below the canopy by creating a different microclimate which might serve as local 
refugia for many species under climate warming scenarios. Forest buffering 
capacity varies greatly depending on forest structure or macroclimatic temperature, 
and is severely threatened by increasing forest fragmentation and land use change 
that create more forest edges, whose buffering capacity is lower compare to forest 
interiors. Worldwide, a significant extent of the total forest area is located next to a 
forest edge and therefore subjected to strong edge effects. Edge effects are regarded 
as one of the main drivers of habitat fragmentation impacts on biodiversity. 
However, our understanding of how the forest respond to this alteration is based 
almost exclusively on herb layer community studies, although this is not sufficient 
to understand forest understorey community responses. Particularly, edge effects 
on the soil seed bank of temperate forests in the context of climate change are 
scarcely studied. This is a shortcoming as the soil seed bank is a key component of 
the biodiversity of plant communities and plays a crucial role in forest 
conservation, population dynamics and forest functioning. 
The main goal of this research was to assess forest edge effects on soil seed bank 
composition and diversity along macroclimatic and microclimatic gradients and in 
relation to climate change. To reach this objective we studied the soil seed bank of 
ancient European temperate deciduous forests with two field experimental studies 
(realised soil seed bank) and a greenhouse experiment (potential soil seed bank).
Besides quantifying the amount and diversity of seeds stored belowground, we also 
focused on the germination responses and seedling establishment as the 
environmental conditions required in these early stages as well as the impacts of 
environmental changes on them can differ greatly from that of the adults. A deeper 
knowledge of seed germination and seedlings' development and adaptations to 
1
forest microclimate is pivotal as the establishment is a critical phase in the plant life 
cycle. In the field studies, we focused on two distinct climatic regions and forest 
types (thermophilous forests of Italy and mesophilous forests of Belgium). We 
sampled the soil seed bank and then, through the installation of experimental plots 
in the forest, we translocated the soil from the forest edge to the interior (and vice 
versa) and from high to low elevation forests (to simulate climate warming). In the 
greenhouse experiment, we covered a 2300 km latitudinal gradient crossing nine 
European regions. We compared the persistent soil seed bank collecting soil 
samples in 90 plots from northern to southern Europe, from low elevation to high 
elevation forest, from dense to open forests and from the forest edge to the forest 
interior. 
Edge effects altered the soil seed bank diversity and composition by increasing the 
proportion of open habitat and generalist species. However, no significant influence 
on the proportion of typical forest species was observed. These findings highlight, 
on the one side, the importance of protecting large forest areas to reduce the inflow 
of external seeds in the soil seed bank and avoid potential compositional shifts and, 
on the other side, the ecological value of forest edge microhabitat, which is not 
unsuitable for the persistence of forest herbs seeds and seedlings. The present 
amount of typical forest herbs stored as persistent seeds in forests suggests that the 
contribution of soil seed banks towards the survival of forest species in 
communities undergoing environmental changes could be substantial. At least in 
the short term, seed banks are expected to buffer environmental variations induced 
by the edge effect through the maintenance of belowground species richness and 
thus through effects on the aboveground community composition. Additionally, 
simulated climate warming changed both the taxonomic and the functional 
composition of the realised soil seed bank, with negative consequences on the 
germination of forest herbs and the increase of warm-adapted species in the 
realised communities. Climate warming is thus expected to induce compositional 
2
and functional shifts in temperate forest understorey communities through 
constraints in the germination of soil seed bank species. These changes might result 
in altered forest biodiversity and functioning. With future rising temperatures, 
dense forest cover and management practices that do not cause the opening of the 
canopy on a large scale should be adopted. In this way, temperature extremes 
would be better buffered and the conservation of shade-tolerant forest species of 
the understorey more likely be assured. Indeed, we found that forest structure 
affected the germination responses from the seed bank. Specifically, denser 
canopies promoted forest species regeneration whereas open canopies promoted 
those of light demanding and generalist species. 
This PhD research gives a novel perspective on the impact of forest fragmentation, 
edge effects and climate change on temperate forest ecosystems and provides 
guidelines on how to preserve biodiversity through the soil seed bank. We suggest 
that the expected combined negative effects of climate change and edge effects 
might be partially mitigated in the future by preventing further forest 
fragmentation, by management of the existing forest edges and by the use of forest 
management methods that prevent the creation of large clearings. Finally, we 
provide a complete list of species and relative abundance of the realised and 
potential soil seed banks along forest edges and interiors of temperate European 
forests, from Norway to Italy. We believe that this can be an important tool for 
forest managers oriented to conservation goals. Further, we expect that this 
knowledge may be a valuable starting point for future studies and a basis for 
resurveys to monitor the effects of changing climatic conditions on forest 
ecosystems.}},
  author       = {{Gasperini, Cristina}},
  isbn         = {{9789463576185}},
  language     = {{eng}},
  pages        = {{XIV, 326}},
  publisher    = {{Florence University ; Ghent University. Faculty of Bioscience Engineering}},
  school       = {{Ghent University}},
  title        = {{The effects of macroclimate and microclimate on soil seed banks in temperate forests}},
  year         = {{2023}},
}