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    Effect of InvasiveRhododendron ponticumL. on Natural Regeneration and Structure ofFagus orientalisLipsky Forests in the Black Sea Region
    (Mdpi, 2020) Vacek, Zdenek; Vacek, Stanislav; Esen, Derya; Yildiz, Oktay; Kral, Jan; Gallo, Josef
    Biological invasions threaten global biodiversity and forest ecosystems; therefore, it is necessary to use appropriate strategies for combating the spread of invasive species. Natural regeneration of eastern beech (Fagus orientalisLipsky) is considerably limited by an aggressive invasive shrub, pontic rhododendron (Rhododendron ponticumL.), in the Black Sea Region of Turkey. Therefore, the future character of the region's forests is uncertain. The aim of this research was to evaluate the structure of beech forests with different management regimes of rhododedron and to determine the interaction among tree layer, rhododendron cover, and natural regeneration in Duzce Province using the FieldMap technology. The following variants of forests were compared: without intervention (control) and three and six years after rhododendron clearance. The results showed that tree density ranged between 175-381 trees ha(-1)and stand volume between 331-589 m(3)ha(-1). The horizontal structure of the tree layer was mostly random, and the spatial pattern of natural regeneration was aggregated. Recruit density and height in the beech stands were significantly differentiated due to the influence of presence or absence of invasive rhododendron. Rhododendron cover ranged between 81%-97%, and woody stems amounted to 72,178-86,884 ha(-1)in unmanaged forests. Canopy in the overstory did not have a significant effect on the density of regeneration and rhododendron cover. Tree layer had a significant negative influence on natural regeneration within a 4 m radius on the plots without rhododendron. However, on the plots with dense rhododendron cover, tree layer had a positive influence on regeneration within a 1.5 m radius. Natural regeneration density was significantly higher when rhododendron was cleared than the plots without intervention. On the plots without woody clearance, there was an insufficient regeneration (113-619 recruits ha(-1)); however, they had higher mean height compared to the sites without rhododendron. After three and six years of rhododendron clearance, the numbers of recruits in natural regeneration were 63,981 ha(-1)and 105,075 ha(-1), respectively. In conclusion, invasive spread of rhododendron was a limiting factor of the prosperous regeneration and tree species diversity, and manual clearance of rhododendron is recommended in managed beech forests of the study region.
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    The Impact of Recreational Use on Land Cover at Uludag National Park (Turkey)
    (Istanbul Univ-Cerrahpasa, 2021) Uzun, Serir; Cakir, Gunay; Yildiz, Oktay; Aksoy, Necmi; Sarginci, Murat; Toprak, Bulent; Muderrisoglu, Haldun
    The intense pressure resulting from population growth and urbanization along with technology has created the need for utilizing natural areas for tourism and recreational purposes and has necessitated the protection, development, and planning of natural resources for people to benefit from. Due to the importance of determining temporal changes within the framework of the protection use balance, this study examined the changes occurring within the recreational areas of the Uludag National Park between the years 1970 and 2010 from human use. As a result of the recreational facilities offered to visitors, an average of 550 000 people benefits annually from the area, which was designated as a national park in 1961. The study included the camping and picnic sites of Sarialan, cobankaya, Kirazliyayla and Karabelen situated within the park and the ski site of the first development zone. High-resolution satellite images and aerial photographs of the areas at different dates were employed. The temporal changes in the selected areas were analyzed by digital image processing with the help of the geographic information system. Upon examining the impact of the recreational use changes occurring on the land cover, it was revealed that building areas had increased by 15 ha (2.57%), road areas by 21 ha (7.89%), and bare land areas by 67 ha (.53%), while the meadowland areas had decreased by 223 ha (119.37%). The forested areas had increased by 78 ha (48.93%), woodland areas by 79 ha (59.37%) and were not adversely affected, mainly due to the protection status of the park.
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    Potential Usage of Some of the Ground-Cover Vegetation for Ecosystem Restoration Practices in Central Anatolian Region of Turkey
    (Istanbul Univ-Cerrahpasa, 2021) Yildiz, Oktay; Cakir, Ernaz Altundag
    Lona-term animal grazing and agricultural practices in the Central Anatolian Region have disturbed the vegetation cover and rendered the sites prone to erosion. Plantation practices have been carried out for about six decades in the region. However, tree-oriented plantation practices have not shown promising results. Thus, experimental data gathered in the region using new approaches with different plant species are urgently needed. The aim of the current study is to evaluate the potential usage of some of the ground-cover species for ecosystem restoration in the region. The seeds of 16 local species were collected during extensive field surveys in the summer and early fall of 2012 and 2013. Five sites scattered on the basin were chosen as experimental blocks. The area covers the driest part of the region, with less than 300 mm annual precipitation and 11 degrees C average temperature. Soil texture for the first 20 cm of soil depth in the experimental units ranges from clay to sandy clay loam, with a high lime content. In October 2012, April 2013, October 2013, and April 2014 seeds of these 16 species were sown on three 40 cm x 600 cm beds. In the spring and summer of 2013 and 2011, sites were visited, and field emergence rates and seedling growth were recorded. Based on the results of the experiment, Atriplex hortensis. Glaucium corniculatum, Marrubium pawiflorum, Onobrychis tournefortii, Peganum harmaia. Reseda lutea. Stachys cretica. Teucrium odium and Vicia cappadocica appear to be the most promising ground-cover spedes for ecosystem restoration in the region.
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    Reclamation of abandoned magnesite site using amendments and plantation
    (Wiley, 2024) Kaptanoglu, Aliye Sepken; Coemez, Aydin; Yildiz, Oktay
    This study aimed to determine the suitable reclamation ways of post-mining magnesite. It was hypothesized that adding amendments and planting would decrease pH, increasing the nutrient availability and enhancing the soil microbial activity. Treatments included 200 g gypsum, 2 kg goat manure, and 200 g sulfur per square meter. Cedar (Cedrus libani A. Rich.), black locust (Robinia pseudoacacia L.), black pine (Pinus nigra J.F. Arnold), and sainfoin (Onobrychis sativa L.) were planted. Before and after the treatments, samples were taken from each experimental unit and analyzed. Analysis of the data indicated that the pH had decreased by 0.6 and 0.5 units on the gypsum + sulfur- and gypsum + manure-treated experimental units, respectively, compared to the other treated plots. In addition, using manure significantly increased the organic matter N, P, and K content, by 3-fold, 2.5-fold, 7.5-fold, and 2.5-fold, respectively, and enhanced microorganism activity. The sulfur + manure treatment increased microbial C and N approximately twofold. Because the manure, sulfur, and gypsum treatments improved the tailings conditions for plant growth, the use of these amendments for mine tailing reclamation was strongly recommended. Across all treatments, cedar and black pine demonstrated 83 and 77% survival rates for the first 3 years of afforestation, respectively. For the same period, the black locust survival rate was 35% lower than that of the other species. The gypsum + manure application increased seedling height growth by about 20% for all three species compared to the other treatments.