Changes in weed populations due to land use and ecological parameters in the Yüksekova basin

This study was conducted in Gever plain located in the Yüksekova Basin, Turkey. The survey studies were carried out during 2020-2021 at 232 different locations in the region. Weed species, and their prevalence and densities in the Gever plain were recorded through survey studies. The relationships between weed species and some physical and chemical properties of the soil was quantified through multivariate analysis. Current and future distribution areas of identified species with high population density and different life strategies in Turkey were predcited. Natural enemies (fungal diseases and pests) on weeds were identified. The 500 g soil samples (0-20 cm depth) collected from 50 different locations representing the study area were used to determine weed seed reserve in the study aerea. The surveys conducted in the Gever plain identified a total of 232 genera and 404 plant species belonging to 52 families, including 1 seedless, 10 monocotyledonous and 41 Dicotyledonae. In the basin, Asteraceae (69 species), Poaceae (52 species), Fabaceae (31 species), Brassicaceae (29 species), Lamiaceae (25 species) Apiaceae (21 species), Caryophyllaceae (15 species), Ranunculaceae (11 species), Plantaginaceae (10 species) and Rosaceae (10 species) families were represented with the greatest number of species. Soil properties of the study area showed significant regional variation. It has been observed that certain weeds can be affected by the soil pattern. Conical Correspondence Analysis (CCA) revealed that texture, organic matter, pH, lime, available phosphorus and potassium have significant effect on weed species' distribution and their density. In addition, 22 different weed species were determined as water indicator of high ground water levels. Current distribution areas of Chenopodium album L. and Ranunculus diversifolius Boiss. & Kotschy and their potential spread in the future were modeled. Modeling studies revealed that there may be significant changes in the distribution areas of these species depending on the temperature increase and the total amount of precipitation. A total of 103 microfungi (obligate, leaf pathogen and saprotroph) species were detected on 79 weed species from 29 different families in the study area. In addition, 57 insect species belonging to 18 families were found feeding on 23 different weed species (leaves, flowers, seeds, stems and roots). In addition, 29 different aphid species feeding on 25 weed species were recorded from the region. The seed bank studied recorded the seed reserves of 79 weed species belonging to 27 families. The number of weed seeds per square meter varied between 400 - 635600 seeds/m2 with an average of 49149 seeds/m2. The dominant species with the highest sed reserves in the region were: Chenopodium albüm L., Carex spp., Ranuculus arvensis L., Eleocharis quinqueflora (Hartmann) O. Schwarz, Carex distans L. subsp distans, Ranunculus diversifolius Boiss. & Kotschy, Trifolium repens L. var. repens and Veronica arvensis L.