About some morphological and morphometric features of Opuntia engelmannii subsp. lindheimeri (Cactaceae), naturalised in the "Cape Martyan" Nature Reserve (Crimea).
The article deals with the problem of biological invasions, including the expansion of alien species into Protected Areas. The total area of the "Cape Martyan" Nature Reserve is 2.4 km2, of which 1.2 km2 is dry land and the other 1.2 km2 is the water surface of the Black Sea. It is located on the Southern Coast of the Crimea and is included in the list of priority areas for the conservation of biodiversity. Sixty-two species of vascular plants (11.2% of the Nature Reserve "Cape Martyan" flora) are classified as alien in the Protected Area. But the invasive status has been determined only for Bupleurum fruticosum, Clematis flammula, Senecio cineraria, and Rhamnus alaternus. The spontaneous dispersal of Opuntia engelmannii subsp. lindheimeri plants in anthropogenically transformed communities was indicated including the Artemisietea vulgaris class, as well as natural communities with a combination of species from the Quercetea pubescenti-petraeae and Cisto-Micromerietea julianae classes. It confirms that this Opuntia has been naturalised in the Protected Area and has the status of an invasive species. The research of the morphometric parameters of cultivated and naturalised prickly pears both on the Southern Coast of the Crimea and in the "Cape Martyan" Nature Reserve was conducted in 2014-2017. It was established that the largest size of segments and fruits is typical for plants growing in semi-open juniper-oak forest communities. The largest number and the longest of spines were recorded on the cultivated plants in rarefied semi-shrubby communities and on open slopes.