Landscape dynamics in Mediterranean oak forests under global change: understanding the role of anthropogenic and environmental drivers across forest types

Abstract

The Mediterranean region is projected to be extremely vulnerable to global change, which will affect the distribution of typical forest types such as native oak forests. However, our understanding of Mediterranean oak forest responses to future conditions is still very limited by the lack of knowledge on oak forest dynamics and species-specific responses to multiple drivers. We compared the long-term (1966-2006) forest persistence and land cover change among evergreen (cork oak and holm oak) and deciduous oak forests and evaluated the importance of anthropogenic and environmental drivers on observed changes for Portugal. We used National Forest Inventories to quantify the changes in oak forests and explored the drivers of change using multinomial logistic regression analysis and an information theoretical approach. We found distinct trends among oak forest types, reflecting the differences in oak economic value, protection status and management schemes: cork oak forests were the most persistent (62%), changing mostly to pines and eucalypt; holm oak forests were less persistent (53.2%), changing mostly to agriculture; and deciduous oak forests were the least persistent (45.7%), changing mostly to shrublands. Drivers of change had distinct importance across oak forest types, but drivers from anthropogenic origin (wildfires, population density, and land accessibility) were always among the most important. Climatic extremes were also important predictors of oak forest changes, namely extreme temperatures for evergreen oak forests and deficit of precipitation for deciduous oak forests. Our results indicate that under increasing human pressure and forecasted climate change, evergreen oak forests will continue declining and deciduous oak forests will be replaced by forests dominated by more xeric species. In the long run, multiple disturbances may change competitive dominance from oak forests to pyrophytic shrublands. A better understanding of forest dynamics and the inclusion of anthropogenic drivers on models of vegetation change will improve predicting the future of Mediterranean oak forests.

Disentangling the climatic and biotic factors driving changes in the dynamics of Quercus suber populations across the species‘ latitudinal range

“…This reduced recruitment could be even more important if we take into account other interacting factors operating at local scales not evaluated here. For example, high levels of seed predation (Pérez‐Ramos & Marañón, ), overgrazing (Acácio et al, ) or eventual fire could further suppress Q. suber populations and could be responsible for the high interpopulation variability in recruitment found in this study.…”

“…This reduced recruitment could be even more important if we take into account other interacting factors operating at local scales not evaluated here. For example, high levels of seed predation(Pérez-Ramos & Marañón, 2008), overgrazing(Acácio et al, 2017) or eventual fire could further suppress Q. suber populations and could be responsible for the high interpopulation variability in recruitment found in this study.The effect of latitude on Q. suber demography became stronger with ontogeny. We found a trend towards lower sapling densities at the southern part of the distribution and higher dominance of adult individuals.…”

“…The Mediterranean region is expected to be one of the most vulnerable to global change over the coming decades due to a combination of different pressures (Giorgi & Lionello, ). However, despite the rising number of modelling studies aiming to predict consequences of global change for tree species distributions (Correia, Bugalho, Franco, & Palmeirim, ; López‐Tirado, Vessella, Schirone, & Hidalgo, ), potential trajectories for the future dynamics of typical Mediterranean forests such as oak forests remain largely uncertain (Acácio, Dias, Catry, Rocha, & Moreira, ; Lindner et al, ). Among oaks, this uncertainty is particularly true for cork oak ( Quercus suber L.) (Vessella, López‐Tirado, Simeone, Schirone, & Hidalgo, ).…”

Ectomycorrhizal fungal diversity and community structure associated with cork oak in different landscapes

“…Adaptations to local environmental conditions could drive cork oak population genetic divergence (Ramírez-Valiente et al 2009a), but the moderate capacity of this species to cope with severe drought could lead to the disappearance/scarceness of actual populations (Ramírez-Valiente et al 2009b). Since a reduction in water availability is expected in the near future (Giorgi and Lionello 2008), the long-term sustainability of these ecosystems may be further threatened, leading to a decrease in Q. suber growth and productivity (Moricca et al 2014;Acácio et al 2017). Regarding these environmental challenges, cork oak forest decline could have implications beyond economic losses, including microbial, plant, and animal diversity losses (Hector et al 1999).…”

Characterizing Factors Associated with Built-Up Land Expansion in Urban and Non-Urban Areas from a Morphological Perspective

“…Anthropogenic impact on the environment is powerful, irreversible, and highly visible [4][5][6], and it plays in interactions between city areas and global environmental change [7,8]. The rapid urbanization process in Zhejiang (one of the richest province in China), characterized by large-scale rural-urban migration and rapid expansion of built-up land areas, has led to enormous arable land loss and serious environmental problems at an unprecedented rate [9][10][11].…”