Conservation assessments of Văcărești urban wetland in Bucharest (Romania) : land cover and climate changes from 2000 to 2015

anglais. Văcărești Urban Wetland, a recently instituted nature park, is situated in Bucharest (Romania). It has been established over the last 27 years within an abandoned retention polder, built during the communist era. Although the area has been disregarded since the construction of the polder ceased, the importance of the Văcărești ecosystem was recently acknowledged by various international associations, due to its great biological diversity and presence of protected species. The aim of this research is to analyse how land cover has changed over the last decade, and to assess if climate change has influenced the habitats of species and therefore biodiversity. The present study focuses on the Văcărești Wetland during the time interval 2000-2015. Satellite images have been used to estimate the percentage cover of six Land Cover Types (LCTs): bare soil, water bodies, water species, reed beds, open land and woody species. Climate variables, i.e. temperature and precipitation, have been collated from the European Climate Assessment and Dataset and used to document the main trends in temperature and precipitation of the study area since 2000. These climate data have also been used as explanatory variables to run Redundancy Analyses (RDA) to assess the LCT variation explained by each of those explanatory variables. Further, lists of plants, birds, insects and other animals have been synthetized based on the Substantiation Note that pursues the implementation of Văcărești Nature Park’s protection regime in order to link each LCT to the diversity of species. Note that the lists of species are available for the present only. The analysis indicated that temperature and precipitation specifically influence the water-related land cover types, which include water bodies, water species and reed beds. The reed LCT recorded a major increase throughout the studied period. Given that the presence of species depends on their specific physiological requirements, and therefore the availability of their respective habitats, I found that hydrophilic plants recorded an increase throughout the studied period. As local temperature and precipitation displayed an increasing trend between 2000 and 2015, it is assumed that the species that depend on the hydrophilic plants would also increase in the future. The results of this study could provide complementary support for the implementation of wetland conservation strategies. These strategies have the purpose of protecting the resources of the ecosystem and potentially enhance the species diversity of Văcărești Wetland.

anglais. Situated near the center of Bucharest, the capital city of Romania, Văcărești Urban Wetland is a vast open land that shelters a great variety of plant and animal species. Although the wetland’s use underwent several changes throughout time (from swamp to vegetable gardens and retention polder), the thriving ecosystem started to develop without any human intervention since 1989. As great interest is shown all around the world in conserving natural areas within cities, due to the ecosystem services that these provide for the inhabitants, efforts have been made for Văcărești Wetland to become a protected area. As a result of the diversity of species found within, in spite of being totally surrounded by urban tissue, the urban wetland has recently been declared a nature park. The present study aims at analysing the potential effects of climate change over the development of Văcărești Urban Wetland between the 2000 and 2015 time interval, by use of satellite imagery interpretation. To this end, six different types of habitats have been defined (bare soil, water bodies, water species, reed, open land and woody species) and their evolution was correlated with two different climate parameters: air temperature and precipitation. Each species of the ecosystem was then associated to one or more habitat types in order to find out to what extent these have been affected by the ongoing climate change and how they might react in the future. The results showed that temperature and precipitation may have an impact upon the habitats distribution. Accordingly, it seems that the species which depend on the reed habitat recorded the most increase during the studied period, followed by water species, while water bodies and open land recorded decreased species presence. As water species represent a great support for biodiversity, further increase in this land cover could have a beneficial effect for the wetland. However, the increase of reed and decrease of open land might have negative consequences upon the species diversity, as the majority of species that are found in Văcărești Wetland do not require habitats similar to that of reed, but are most supported by open land habitats. The conclusions of this study could be used in order to limit the negative impact of climate change on the wetland, by means of contributing to the development of suitable conservation strategies for the ecosystem of Văcărești Urban Wetland.