The climate drives species distribution and genetic diversity; the latter defines the adaptability of populations and species. The ongoing climate crisis induces tree decline in many regions, compromising the mitigation potential of forests. Scientific‐based strategies for prioritizing forest tree populations are critical to managing the impact of climate change. Identifying future climate refugia, which are locations naturally buffering the negative impact of climate change, may facilitate local conservation. In this work, we conducted the populations' prioritization for Castanea sativa (sweet chestnut), a Neogene relict growing in the Caucasus global biodiversity hotspot. We generated genetic and ecological metrics for 21 sites in Georgia and Azerbaijan, which cover the natural range of sweet chestnut across the region. We demonstrated that climate primarily drives the pattern of genetic diversity in C. sativa, proved with a significant isolation‐by‐environment model. In future, climate change may significantly reorganize the species' genetic diversity, inducing even some genetic loss, especially in the very distinct eastern fringe of the species range in Azerbaijan. Based on our combined approach, we mapped populations suitable for ex situ and in situ conservation, accounting for genetic variability and the location of future climate refugia.

Scots pine is one of the most widely occurring pines, but future projections suggest a large reduction in its range, mostly at the southern European limits. A significant part of its range is located in the Caucasus, a global hot-spot of diversity. Pine forests are an important reservoir of biodiversity and endemism in this region. We explored demographic and biogeographical processes that shaped the genetic diversity of Scots pine in the Caucasus ecoregion and its probable future distribution under different climate scenarios. We found that the high genetic variability of the Caucasian populations mirrors a complex glacial and postglacial history that had a unique evolutionary trajectory compared to the main range in Europe. Scots pine currently grows under a broad spectrum of climatic conditions in the Caucasus, which implies high adaptive potential in the past. However, the current genetic resources of Scots pine are under high pressure from climate change. From our predictions, over 90% of the current distribution of Scots pine may be lost in this century. By threatening the stability of the forest ecosystems, this would dramatically affect the biodiversity of the Caucasus hot-spot.

The city – a modern jungle, where not cellulose and photosynthesis but concrete and combustion reign supreme. The question now being asked by urban planners, governments, and scientists is if it may stay like that and if it can stay like that or if it has to stay like that. Social, economic, cultural, historical, and legal factors are determinants in the ecology of urban ecosystems. Even well-managed cities are usually hostile toward non-human inhabitants. Furthermore, as with any complex system, the equilibrium is fragile, even if it exists. This publication outlines the co-evolution and ecology of humans and other species in the cities, their importance, and perspectives.

Cupressus atlantica is a narrow endemic species of semi-arid and sub-humid habitats in the western High Atlas, Morocco. We explored the possible dynamics of the species’ range under climatic changes using species distribution modelling (SDM) to identify populations vulnerable to range changes. Additionally, we investigated the spatial genetic structure (SGS), the effective population size and genetic connectivity in natural populations, which may provide important data on demo-genetic processes and support the conservation management of this critically endangered species. The SDM results showed that the current species range constitutes only 49% of the potential distribution. Under the most pessimistic scenarios (RCP6.0 and RCP8.5), a significant reduction in the species range was predicted. However, the projection based on RPC4.5 revealed possible extensions of the habitats suitable for C. atlantica. Potentially, these areas could serve as new habitats that could be used with the assisted migration approach aiming to mitigate the current fragmentation. In terms of the SGS, significant and positive aggregation of relatives was detected up to ca. 100 m. In comparison to other fragmented and endemic species, the detected SGS was weak (Sp = 0.0112). The estimated level of recent gene flow was considerable, which likely prevented a strong SGS and allowed diversity to accumulate (H_E = 0.894). The most alarming results concern the effective population size, which was very low in the studied populations (< 53), suggesting a possible increase in inbreeding and loss of diversity in the near future. More effective conservation actions integrating in situ and ex situ measures should be undertaken to prevent extirpation of the species.

The Caucasus ecoregion is located between the Black and the Caspian Sea and extends from southern Russia, throughout Turkey, Georgia, Armenia, Azerbaijan up to Iran. The prominent feature of the region is high biodiversity and endemism. The outstanding biological richness made the Caucasus one of the 36 global hotspots of biodiversity. The Caucasian forest is concentrated mainly in Georgia, where the most diverse forest ecosystems are found. In the Colchis forest, Tertiary relicts are present and this area formed glacial refugium for flora and fauna. However, the region and its wildlife are now under threat. Uncontrolled logging, urban and agricultural development, and climate changes bring about the great risk for many species and unique plant assemblages. The massive decline of Castanea sativa (sweet chestnut) exemplifies the problems of the alien parasite invasions and ineffective forest management and nature conservation. Biodiversity of the Caucasus is being lost at an alarming rate that calls for urgent action and intensification of investigations aiming at better understanding of the evolutionary history of the region.

The Mediterranean Basin is one of the 36 global hotspots of biodiversity and it is rich in endemic tree species. The complex geological history of the region throughout the Neogene and Quaternary periods that were marked with several palaeoclimatic transformations was a major factor triggering the genetic divergence of lineages in tree species in the region. The ongoing global climate change is the main factor threatening Mediterranean biodiversity. The risk of population decline related to aridization is the highest in the case of endemics, especially for cold-adapted conifers, such as Abies cilicica. The Cilician fir grows in the East Mediterranean mountains that constitute a local centre of endemism within the region. The species range is fragmented and small-size populations prevail. Previous studies have suggested that the last glacial cycle led to a significant reduction in the species range and might have initiated genetic divergence. As a result, two lineages are currently recognized at the subspecies level, A. cilicica subsp. isaurica (Turkey) and A. cilicica subsp. cilicica (Turkey, Syria, and Lebanon). The predictions about the impact of future climate changes in the East Mediterranean suggest a profound reduction of precipitation and overall warming that may put the remnant populations of A. cilicica at a risk of decline. Here, we used the Bayesian approach to investigate the demographic history of endemic A. cilicica. Specifically, we estimated the probable time of the intraspecies divergence to verify previous assumptions about the species’ evolutionary history. Additionally, niche modelling was used to outline the potential range of changes in the past and to indicate glacial refugia in where the species persisted climate crisis. This approach was also used to explore the possible influence of the future climate changes on the distribution of A. cilicica in the region. Our results demonstrate that the divergence between the Lebanese and the Turkish populations that occurred ~220 ka years BP coincided with the Riss glaciation. According to palaeoecological data, in the East Mediterranean, that glacial period caused a severe reduction in the populations of woody species due to the aridity of the climate. At that time, the Lebanese-Syrian part of the range was likely disconnected from the main range. The second split was induced by the last glacial cycle ~60 ka years BP and led to the separation of the Central Taurus and East Taurus population and, consequently, to the formation of the two subspecies. Niche modelling for the last glacial maximum has allowed us to locate the probable refugia for A. cilicica in the western Anatolia and Syria-Lebanon area. A projection of the future possible distribution of the species indicates a serious reduction of the range during this century.