A taxonomic study on nematode diversity of some terrestrial trees in Türkiye: a case study in Tekirdağ

The current study was conducted in 2024 in Süleymanpaşa, Tekirdağ to determine the nematode biodiversity in the black poplar [Populus nigra L. (Malpighiales: Salicaceae)], Himalayan cedar [Cedrus deodara (Lamb.) G.Don (Pinales: Pinaceae)], cypress [Cupressus sempervirens L. (Pinales: Cupressaceae)], oriental plane [Platanus orientalis L. (Proteales: Platanaceae)], common ash [Fraxinus excelsior L. (Lamiales: Oleaceae)], stone pine [Pinus pinea L. (Pinales: Pinaceae)], and black locust [Robinia pseudoacacia L. (Fabales: Fabaceae)] growing areas. Soil samples were collected from the 0-60 cm soil depth of each tree rhizosphere. Nematodes were extracted using the centrifuge flotation method, and identifications were made using polytomous keys. In the study, 38 genera were identified in the rhizosphere soil of stone pine, 32 in Himalayan cedar, 36 in cypress, 34 in oriental plane, 31 in black locust, 27 in common ash, and 27 in black poplar. Cephalobus Bastian, 1865 (Rhabditida: Cephalobidae), Aphelenchus Bastian, 1865 (Aphelenchida: Aphelenchidae), Filenchus Andrassy, 1954 (Tylenchida: Tylenchidae), and Geocenamus Thorne & Malek, 1968 (Tylenchida: Merliniidae) were common genera across all tree species. Taxonomic diversity indices were calculated to compare nematode diversities at different taxonomic levels. The Shannon diversity index (H′) ranged from 2.99 to 3.41, Evenness (J′) from 0.90 to 0.95, Maturity index (MI) from 2.29 to 2.48, and Plant-parasitic index (PPI) from 2.84 to 3.02. Analysis by trophic groups revealed that plant parasitic and bacterial feeder nematodes were more prevalent in all tree species.