Assessment and rational use of biological diversity is one of the main concerns of our days, and its preservation is an essential condition for maintaining the ecological balance in nature and sustainable development of social – economic systems. The consequences of technical-scientific development of society, besides its obvious advantages, continues to intensify the diminishing of diversity of the vegetal and animal world, especially in conditions of socio-economic and political transition, having as effect a high number of species that have considerably diminished their number and areas. The scientific data show that during time the disappearance of numerous biological species was based on human actions more or less negative, following which the biosphere rapidly loses its ability to self-regulate [1.]. The main anthropic threat to the diversity of the living world is the destruction of natural habitats resulting from the exponential growth of human population, the demand for natural resources and enormous mass of polluting and degrading waste. Intensive use of farmland, pollution of water, atmosphere and soil, reduction of areas with natural vegetation caused worsening of living conditions and diminishing of distribution area of many plants and animals species. Other current threats faced by natural ecosystems are the unprecedented climate change and invasive species, significantly affecting the biodiversity. One of the most dangerous consequences of these phenomena (local, regional and hence global) is the irretrievable disappearance of a large number of biological species, many of which have not yet been discovered by the science. Thus, the socio-economic activity of the man causes biosphere collapse by reducing its elementary components - species, their communities and consequently of many ecosystems. The Red Book of the Republic of Moldova serves as scientific support for developing measures and protection regimes of all species of plants and animals, as well as for proposals, amendments to laws and regulations on biodiversity, in order to improve environmental legislation in force and its harmonization with European Community rules. It contributes to the necessary strengthening of Government, national institutions and organizations responsibilities in the field of implementation of international conventions provisions, to which Moldova is Part, as well as of the national Strategy and Action Plan on Biodiversity Conservation and to the realization of environmental education for the entire population of our country. In this context two pilot districts – Soroca and Stefan Voda – were selected, both rich in biodiversity and having territories included in the two Ramsar cites. Moreover, these regions are different in terms of economic conditions. In Soroca district 101 species with rarity status have been identified, of which 62 animal species and 39 plant species. Among them two secular trees. Of the 62 species of animals 6 are mammals, 10 - birds, 4 - reptiles, 8 - amphibians, 6 – fish and 28 - insects. The majority of rare species identified in the Soroca district area are endangered and vulnerable. Many of them are concentrated in forests and less in steppes, plains and water basins. Rare species were found in number of 1-2 on restricted surfaces. In all the studied areas many rare species are registered in the territories managed by Moldsilva Agency. In Stefan Voda district 87 species with rarity status have been identified, of which 57 animal species (10 - mammals, 13 - birds, 4 - reptiles 2 - amphibians, 13 – fish and 15 - insects) and 30 plant species. Among them four secular trees. Rare plants and animals from Stefan Voda district contain a considerable number of endangered and vulnerable species. Overall, it can be observed a state of vulnerability in rarity status of many species, even if they are near or far from natural areas protected by state from Lower Nistru zone. Most of species have been identified in protected areas along the Nistru river. The vulnerable potential of rare species is spread in water meadows, forests and meadows and less in steppes. On more humid habitats 1-3 individuals of rare species have been registered and 1-2 species in forests and steppes. The diversity of plant species in these two districts is particularly high in forests (over 340 species), meadows (550 species) and steppe (over 480 species). Plant species are encountered in forests associated with meadows, steppes with meadows, riparian corridors, most of them concentrated in the Ramsar wetlands. Both districts contain about 69 rare species included in the Red Book, which inhabit different natural habitats. Of the approximately 15300 known species of animals in Republic of Moldova, of which 219 were included in the third edition of the Red Book of Moldova, 119 species have been identified in Soroca and Stefan Voda districts. Most of species were identified in forest ecosystems, meadow and wetlands. Many rare species are threatened with extinction or critically endangered at local, regional and global level (according to the categories and criteria of the IUCN Red List, Bern Convention and EU Habitats Directive lists). In both districts many primary steppe ecosystems are reduced, fragmented and less preserved and typical steppe species are threatened with extinction within their natural spreading area. The species present in the meadow ecosystems, aquatic or wetland areas are also threatened, where there are significant concentrations of rare and endangered species, such as plant species Trapa natans and Salvinia natans, and some animal species (Myotis daubentoni, Nyctalus lasiopterus, Plecotus austriacus) that are protected by the Bern Convention. Many rare and representative species are at the limit of their range, and according to IUCN classification are generally vulnerable, so it is necessary to ensure the rational management of their biodiversity. Many of species have reduced their populations and some have disappeared from their natural area, due to unregulated grazing and grubbing of steppe territories. Overall, rare species are in regression, also due to the penetration of invasive species, especially those ruderal, exotic trees and shrubs (Acer negundo, Ailanthus altisima, Amorpha fruticosa). The agricultural sector continues to be a major threat to the integrity of natural ecosystems, especially for rare and indicator species of forest, meadow and steppe habitats. Implementation of rare species and their habitats conservation will be accomplished after an analysis of the legal framework at national and international level to ensure that the identification of rare species, of vulnerable habitats, of ecosystem goods and services is becoming a necessity in the plans and activities of district planning, in development plans and land use of settlements. The measures aimed to reduce the negative impact upon rare and endangered species are the biodiversity monitoring through the introduction of passports of species / habitats for landowners outside Protected Areas. Acknowledgement: The study was performed in the frame of projects „Evaluation of animal species state and elaboration of rarity criteria in order to actualize the red list” (I stage), „Evaluation of populations status and determining the status of animal species proposed for the IIIrd edition of the Red Book” (II stage) financed by the NEF and project “Mainstreaming Biodiversity Conservation into Moldovaʼs territorial Planning Policies and Land-Use Practices” PNUD/GEF.