ABSTRACT: The relationships between community structure and soil properties (pH, P, N, Ca, Mg, CaCO 3 and clay content) were examined in a swamp forest from the northern part of Turkey. Statistically significant correla- tions were found between the soil variables and three different associations (Fraxino excelsioris- Fraxinetum angustifoliae, Carpino orientalis- Pterocaryetum fraxinifoliae, Acero campestris- Alnetum glutinosae) according to CCA ordina- tion. P, Mg, Ca and clay content of soil were found as four significant variables for species composition in the studied forest. KEYWORDS: swamp forests, vegetation- environment relationships, species diversity Wetlands are habitats where the water table is at or near the land surface, or whe- re the land is covered by shallow water for a sufficient length of time to cause anaero- bic conditions within the root zone of plants (Barnes et al. 2002). Investigations have showed that the natural succession under meso-eutrophic conditions may gra- dually lead to swamp forests. Such forests constitute the climax phase of hydrosere (Prieditis 1997 a; Kutbay 2001). The study area is a swamp forest which covers an approximately 86 ha; it is situated in the Central Black Sea Region at sea level, Northern Turkey (41°18’N; 36°55’E). Climatic and soil properties of the study area are given in Ku t b a y (2001). The cover values of all vascular species we- re estimated in each vegetation layer (tree, shrub and herb layers) according to Braun- Blanquet cover-abundance scale (M u e l - ler-Dumbois and Ellenberg 1974). The size of quadrats were estimated by means of minimal-area method. Ten flori- stically and structurally homogenous plots were taken, (average area of 700 m 2 ), which represent the main vegetation types. Ten soil samples were taken from these plots si- multaneously; they represent the ecologi- cal site ranges for the study area (Kutbay 2001). Soil samples were taken in each plot at a depth between 0 and 30 cm during mid-growing season (August 1994). Soil texture and the other parameters like pH, nitrogen, phosphorus, potassium, magne- sium and CaCO 3 (%) content were deter- mined by standard methods (A l l e n et al. 1986). The data set was classified by TWINSPAN procedure. Cover data of spe- POLISH JOURNAL OF ECOLOGY 52 2 233–238 2004 (Pol. J. Ecol.) Short research contribution Erkan YALÇIN, Ali BILGIN, Hamdi Güray KUTBAY, Mahmut KILINÇ Department of Biology, Faculty of Arts and Sciences, Ondokuz Mayis University, Kurupelit-Samsun 55139, Turkey; e-mail: eryalcin@omu.edu.tr RELATIONSHIPS BETWEEN COMMUNITY STRUCTURE AND SOIL PROPERTIES OF A SWAMP FOREST FROM NORTHERN TURKEY