Aboveground and belowground plant traits and plant economic spectrum in central anatolian steppe vegetation

The functional trait approach has been increasingly used in ecological studies in recent years to understand how species respond to environmental pressures such as global climate change, land use, overgrazing, and similar disturbances, and how these responses affect ecosystem processes. However, a large proportion of these studies focus on aboveground traits, which are relatively easier to measure. Nevertheless, especially in arid and semi-arid ecosystems, where a substantial proportion of total biomass is located belowground, understanding belowground traits is essential for achieving a holistic perspective on these ecosystems. Despite their high biodiversity and endemism, studies on the Central Anatolian steppes using a functional trait approach are quite limited, and no studies have specifically focused on belowground traits. This thesis aims, for the first time, to provide a holistic perspective by examining both aboveground and belowground traits of Central Anatolian steppe plants. In this regard, leaf and root traits that related wtih the plant economic spectrum were measured, and their relationships with each other and with different soil types were studied. This thesis consists of three main sections. In the first section, nine aboveground functional traits (plant height, specific leaf area, leaf thickness, leaf dry matter content, leaf nitrogen content, stem density, seed mass, and seed shape) were measured for 50 plant species representing six different growth forms in a calcareous steppe community, and these traits were shown to differ significantly among growth forms. In the second section, fine root traits (root diameter, root dry matter content, and specific root length) were measured for the first time in 10 common species selected from the same community, and these values were compared with global temperate grassland databases, providing the first quantitative assessment of root traits for Central Anatolian steppe plants. In the third section, comparative analyses conducted on 73 taxa in gypsum, calcareous, and marl steppes revealed that aboveground traits are primarily structured by growth form, whereas belowground traits vary more strongly with soil type. The results indicate that leaf and root economic spectra do not always vary in parallel in semi-arid steppes, but are instead shaped by different environmental filters. This thesis presents one of the first comprehensive assessments of the aboveground and belowground functional trait structure of Central Anatolian steppes. The data obtained can guide future conservation, management, and restoration efforts and contribute to a better understanding of the ecological importance of steppe ecosystems.