The report “Native Trees of the Mediterranean Region: Distribution, Diversity and Conservation Challenges” delivers the most complete inventory to date of native tree species in 39 “botanical territories” across North Africa, Western Asia, and Southern Europe. It addresses critical gaps in occurrence data, extinction risk assessments, and genetic diversity knowledge for one of the world’s most important biodiversity hotspots, now under accelerating climate stress.
The authors identify 643 taxa (496 species and 147 subspecies) from 50 families and 111 genera. Diversity is highly uneven: the Rosaceae family dominates with 147 species, followed by Fagaceae and Salicaceae, while 19 families contain only a single species. The inventory also adds 48 species and 8 subspecies of “cryptic trees” which had not previously been classified as trees in the region. Endemism is significant: 41% of taxa occur only on one continent, with Iran and Türkiye hosting the largest numbers of endemic species.
Patterns of distribution show that:
Species richness correlates strongly with territory area and habitat heterogeneity (elevation and ruggedness).
No clear east–west gradient exists, but richness tends to increase slightly northwards.
Smaller territories such as Bulgaria, Kosovo, and Malta have the highest density of native species per area.
Neighboring territories share more species, showing spatial clustering.
Conservation status raises concern. About 8.3% of taxa are threatened (Vulnerable, Endangered, or Critically Endangered), while 47% are Data Deficient or Not Evaluated, indicating serious knowledge gaps. Threatened species are proportionally more common in Western Asia and North Africa, and strictly Mediterranean species face higher relative extinction risks than those with wider ranges.
Genetic diversity data are largely missing: two-thirds of species have no studies, and research is concentrated on economically important taxa such as timber and food species. Just three families (Pinaceae, Rosaceae, and Fagaceae) account for more than half of all genetic studies. Alarmingly, species at risk of extinction receive very little genetic research attention.
The report offers an open-access dataset that can be used to:
Pinpoint biodiversity hotspots for conservation and restoration.
Guide extinction risk assessments and fill genetic knowledge gaps.
Foster cross-border collaboration to safeguard Mediterranean forest trees.
By identifying where richness, endemism, and threats intersect the study provides a foundation for targeted, urgent action to protect Mediterranean trees in the face of climate change and habitat pressures.