15 th International Conference on Environmental Science and Technology Rhodes, Greece, 31 August to 2 September 2017 CEST2017_00963 Functional diversity and ecosystem resilience in some forests “Natura 2000” sites in Northeastern Romania Acatrinei L. 1* , Huţanu M. 2 , Ivan O. 1 And Călugăr A. 1 1 Institute of Biological Research, 47, Lascăr Catargi Street, Iaşi, Romania 2 “ Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, 3 Mihail Sadoveanu Alley, Iaşi, Romania *corresponding author: e-mail ligia.acatrinei@icbiasi.ro Abstract: Capacity for resilience and ecosystem stability of natural systems based on their biodiversity is required to maintain essential ecosystem goods and services over space and time. Loss of resilience may be caused by the loss of functional groups. Based on this perspective three natural forest ecosystems from “Natura 2000“ Network situated in Northeastern part of Romania were studied. Central Moldavian Plateau is situated at confluence of two bioregions, steppic and continental, thus many species and habitats occur at the limit of their areal. Investigated stands are represented mainly by forest - steppe vegetation with mixed tree species of oaks and hornbeam. Leaf functional traits (gas-exchange parameters, relative water content) were analysed in order to evaluate functional pattern of different trees stands in relation with environmental change, climatic extremes and soil type. For the purpose of the study two groups of soil mites with bioindicator value, Mesostigmata and Oribatida were investigated from both qualitative and quantitative points of view. Dynamics of oribatid and gamasid communities during the two years with different climatic conditions showed significant changes in coenoses structure and spatial distribution of these mites, but also a remarkable stability illustrated by the composition of edifying groups and high specific diversity level. Keywords: “Natura 2000“, functional diversity, forest - steppe, leaf traits, soil mites 1. Introduction Resilience is an important property of ecosystems which is provided by genes, species, functional groups of species and processes within the system. Maintaining or restoring forest resilience is often important to evaluate the particular characteristics of forest ecosystems and the environment, including human-caused disturbances, and respectively, climate change (Thomson et al. 2009). Correlation between aboveground and belowground diversity, despite of some lack of knowledge is recognized as an important challenge for the current ecological approaches. Also, both policies and scientific literature attest the linkage between soil biodiversity and soil quality and health, that influences ecosystem functioning and services (Hooper et al. 2000; Cluzeau et al. 2012). A long- term response of an ecosystem to climate change depends in a great extent on soil subsystem and its inhabitants’ reactions (Kardol et al. 2010) The current research is a continuation of a previous one and represents multi-disciplinary investigations (floristic and phytocoenological, ecophysiological and acarological) of the structure and functioning of protected forest ecosystems (Natura 2000 sites) representative for Central Moldavian Plateau and an impact assessment of natural and anthropogenic factors. The studied area, Central Moldavian Plateau is important because it is at the interference of two bioregions, the mainland and the steppe, thus some habitats and species are here at the limit of their areal. The rugged and hilly relief with chernozem (on moderate slopes), regosols and also, erodisoil (steep slopes), marshy clay (wet meadow), in this region is critically affected by the climatic changes (drought, climatic extremes) with consequences over time. 2. Material and methods 2.1 Study sites Three representative natural forests from “Natura 2000” Network were selected from the geographical area, Moldavian Central Plateau situated in the Northeastern Romania: 1. ROSCI0158 Hârboanca Forest - 46°42′44″N 27°35′34″E, 40.4 ha (Vaslui County) with the Dacian forests of oak and hornbeam on molic vertic stagnic soil. 2. ROSCI0158 Bălteni Forest - 46°40′30″N 27°39′52″E, 18.8 ha (Vaslui County) represented by floodplain forests mixed with oak, elm and ash on preluvosol vertic stagnic soil. Harboanca (1) and Balteni (2) forests belong together in the same community site. 3. ROSPA0096 Micleşti Forest - 46°51′24″N 27°53′12″E 8631 ha (Iasi and Vaslui County), a bird protection zone, a typical forest steppe with hilly mixed oaks on eutricambosol molic vertic stagnic soil. 2.2 Sampling and extraction Based on field research, a floristic list was elaborated which permitted flora analysis and ecological indices calculation. The vegetation analysis was made after Braun- Blanquet method, being included in three phytoassociations. The cormophytes nomenclature followed Ciocârlan (2009).