The Dynamics of Some Ecological Indicator Values and Their Interrelation with Biodiversity, Floristic Composition and Pastoral Value in an Ex-Arable Extensive Forest-Steppe Grassland over 21 Years (Case Study)

Forest-steppe grasslands are highly important ecosystems because they provide the transition from temperate forests to open steppes. This makes them exceptional from many important perspectives, such as biological diversity, ecological services, gene pools, agroecosystem resources, etc. These are some of the main reasons for the demand for long-term studies on topics such as vegetation succession or climate resilience records, because they can be useful for authorities and entities involved in the restoration of these agroecosystems. The aim of the research is to analyse the sward of a successional ex-arable grassland in the Western Romanian forest-steppe area, managed under an extensive system, using Ecological Indicator Values (EIVs) and their interaction with biodiversity, floristic composition (functional groups) and pastoral value. Data collection began in the ninth year after land abandonment, specifically in 2003. The results of the present research are extended to 21 years, covering the period from 2003 to 2023. The Landolt EIVs considered were the preferences for plant species in soil reaction (R), nutrients (N), soil moisture (F), temperature (T), light (L), and climatic continentality (K). The successional evolution of vegetation was highly complex during the study, highlighting changes in species composition, influenced along the time gradient by changes in biotope conditions. These changes were expressed by the trend of most of the analysed EIVs, respectively, temperature (T), soil moisture (F), soil reaction (R), and nutrients (N). EIVs are a useful tool that offers a more detailed description of a permanent grassland, expressing the evolution of the biotope conditions. Biodiversity was influenced by N and K, and floristic composition mostly by K.