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Purpose of Review: Recognizing that in the context of global change, tree genetic diversity represents a crucial resource for future forest adaptation, we review and highlight the major forest genetics research achievements of the past decades in biodiversity-rich countries of the Mediterranean region. For this, we conducted a bibliometric analysis of the scientific literature spanning the past thirty years (1991–2020). Putting together the representative regionwide expertise of our co-authorship, we propose research perspectives for the next decade. Recent Findings: Forest genetics research in Mediterranean countries is organized into three different scientific domains of unequal importance. The domain “Population diversity and Differentiation” related to over 62% of all publications of the period, the domain “Environmental conditions, growth and stress response” to almost 23%, and the domain “Phylogeography” to almost 15%. Citation rate was trending the opposite way, indicating a strong and sustained interest in phylogeography and a rising interest for genetics research related to climate change and drought resistance. The share of publications from Asia and Africa to the total within the Mediterranean increased significantly during the 30-year period analyzed, reaching just below 30% during the last decade. Summary: Describing poorly known species and populations, including marginal populations, using the full potential of genomic methods, testing adaptation in common gardens, and modeling adaptive capacity to build reliable scenarios for forest management remain strategic research priorities. Delineating areas of high and low genetic diversity, for conservation and restoration, respectively, is needed. Joining forces between forest management and forest research, sharing data, experience, and knowledge within and among countries will have to progress significantly, e.g., to assess the potential of Mediterranean genetic resources as assisted migration material wo

According to the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC), global climate change is now unequivocal. Tunisia, like many other countries, has been affected by climate changes, including rising temperatures, intense heatwaves, and altered precipitation regimes. Tunisia's mean annual temperatures has risen about +1.4 °C in the twentieth century, with the most rapid warming taking place since the 1970s. Drought represents a primary contributing factor to tree decline and dieback. Long-term drought can result in reduced growth and health of trees, thereby increasing their susceptibility to insect pests and pathogens. Reported increases in tree mortality point toward accelerating global forest vulnerability under hotter temperatures and longer, more intense droughts. In order to assess the effect of these climate changes on the current state of forest ecosystems in Tunisia and their evolution, an investigative study was required. Here, we review the current state of knowledge on the effects of climate change on sclerophyllous and semi-deciduous forest ecosystems in Tunisia. Natural disturbance during recent years, as well as the adaptability and resilience of some forest species to climate change, were surveyed. The Standardized Precipitation Evapotranspiration Index (SPEI) is a multi-scalar drought index based on climate data that has been used to analyse drought variability. The SPEI time scale analysis showed a negative trend over the 1955–2021 period in Tunisian forest regions. In 2021, Tunisia lost 280 km2 of tree cover to fires, which is equivalent to 26% of the total lost area between 2008 and 2021. Changing climate conditions have also affected phenological parameters, with an advance in the start of the green season (SOS) of 9.4 days, a delay at the end of the green season (EOS) of 5 days, with a consequent extended duration of the green season (LOS) by an average of 14.2 days. All of these alarming findings invite us to see

Acer monspessulanum (Montpellier Maple) is an important deciduous tree species native to the Mediterranean region. It is largely distributed in the southern part of western Europe; however, it is geographically less present in north Africa and western Asia. The effects of the most significant environmental variables for its habitat suitability, and climate change, are unclear in terms of the future changes to its distribution. The objective of the present study was to model the current and future geographical potential distribution of the Montpellier Maple in the Mediterranean basin and West Asia using maximum entropy modeling software (MaxEnt). The value of the Area Under the Curve (AUC) of MaxEnt was used to analyze the model’s performance. More than 5800 well-distributed presence points, elevation, slope, aspect, topographic wetness index (TWI), natural vegetation characteristics from MODIS products, and 19 bioclimatic variables were used to conduct the study. Regarding the projections of the species distribution under climate change, 17 global climatic models were used under two RCP scenarios (4.5 and 8.5) for the 2040–2060 and the 2060–2080 time periods. The results show that temperature seasonality (40% contribution to the model), elevation (33.5%), mean annual temperature (6.9%), mean annual precipitation (6.2%), and max temperature of the warmest month (4.5%) were identified as the primary factors that accounted for the current distribution of the Montpellier Maple. Under the climate change scenarios, MaxEnt predicts a large decrease in the species suitability area, with a shift towards the southwestern regions of the species distribution, especially to the mountainous zones of the Moroccan Atlas. Our results show that climate largely limits the distribution of the Montpellier Maple in the Mediterranean basin, as its change in the future is expected to significantly reduce the suitable area by more than 99% from the historical climate conditions, to reach on

Coastal dune landscapes are subject to morphological and ecological changes. In many parts of the world, coastal dunes are under severe pressure. The present study illustrates an integrated remote sensing and Geographical Information System (GIS) approach, i.e., geospatial techniques for assessing land-cover dynamics in Zouaraa coastal dunes, located in northwest Tunisia. As a main result, the analysis of the situation in the past six decades indicates that the dune area showed a decreasing trend with up to 31% (i.e., 6198 ha) in favour of forest area, which has increased by up to 6485 ha. The geo-spatial analysis revealed that restoration works have positively contributed to stabilize coastal dune systems with a substantial increase in vegetation cover. An increase in drought frequency and intensity was detected during the 1952-2017 period using the SPEI index, which enhanced the vegetation activity and growth in the study area. The SPEI significantly correlated with vegetation greenness on the 12- and 24-months’ time scales. The croplands, water and buildings in the study area have increased respectively by 6% (i.e., 1256 ha), 13% (i.e., 3073 ha) and 3% (i.e., 719 ha). In contrast, land cover like shrub and bare soil has decreased respectively by 13% (i.e., 3073 ha) and 2% (i.e., 1831 ha) during the same period. Furthermore, this study highlights the importance of the revegetation techniques undertaken for conserving coastal dune systems. The findings of this study allow land-use planning decision makers to manage and improve situations in similar coastal regions.

In the climate change context, the severity and duration of drought periods are expected to increase. Forests are known to be extremely sensitive to climate change, especially in the Mediterranean Basin, and particularly in Tunisia, where climate is characterized by dry hot summers which will intensify and prolong due to climate change effects. A better understanding of the mechanisms allowing plants to survive during prolonged drought would help to anticipate expected changes. The present study aimed to analyze the effect of extremely dry years on the mortality and decline of cork oak forests in northwest Tunisia during the 1988–1995 period. Extreme drought years with significant effects on tree growth were registered. Cork oak mortality was recorded for up to 63,622 trees. The study area was largely influenced by the frequency of prolonged drought periods, especially from 1988 to 1995.