Pistacia atlantica (Anacardiaceae) in the South-Eastern Crimea: population characteristics, current status, protection
The article presents the results of monitoring of the population of a relict Mediterranean species Pistacia atlantica Desf listed in the Red Data Book of the Russian Federation. P. atlantica grows in the mountains of South Coast of the Crimea (from Balaklava to Karadag) in the coastal and lower mountain forest belts up to 400 m a.s.l., where it forms rare relict plant communities. Antropogenic impact on coastal landscapes is considered the main threat factor for P. atlantica communities. To date, the ancient Mediterranean forests have shrunk to small groves scattered along the coast, and therefore, they urgently need protection and monitoring. Active measures must be undertaken to restore particular plant species and population. The field research was conducted in 2018-2020. The researchers identified and studied seven populations, four of which had natural origin and three had artificial origin. Sample plots were set up at each site to count the total number of P. atlantica plants and determine their age states. Biomorphological indicators of generative plants were also measured: tree height, number of trunks, trunk diameters at the at the ground level and at the height of 1.3 m. Ontogenetic structure of P. atlantica populations was studied at each site. The age index (Δ), the mean efficiency index (ω) and the regeneration index were calculated and the type of the populations was determined (according to the “delta-omega” (∆-ω) classification). Native populations were identified as young ones (age index (Δ) 0.17-0.24, mean efficiency index (ω) 0.45-0.56 and regeneration index 43.2-158.7 %). They had the left-sided spectra: the pregenerative individuals dominated there. The artificial populations were maturing or mature: age index (Δ) 0.30-0.51, recovery efficiency index (ω) 0.70-0.76, regeneration index 12.8-20.5 %). They had either centered (young or middle-aged generative individuals dominated) or right-sided (old generative individuals dominated) spectra. The average height of the trees in the populations varied from 3.0 to 5.5 m. The authors found a significant positive correlation between this parameter and annual precipitation values. The average number of tree trunks in the populations ranged from 1.4 to 2.4. This parameter is significantly and negatively correlated with annual amount of precipitation. On the other hand, the temperature effect on the morphological parameters was statistically insignificant. The state of all the studied populations was considered normal, general phytosanitary state of the trees was satisfactory. A new locality of P. atlantica was found, thus, it was proved that the habitat of this species expanded to Feodosiya. The main risk factor for this species in the South-Eastern Crimea is the habitats reduction due to anthropogenic pressure on natural areas and resort construction.