PEP725, the European phenological database
Authors: Scheifinger Helfried , Ressl Hans , Hübner Thomas , Ungersböck Markus 
Published: February 2023

&#8220;Phenology &#8211; the timing of seasonal activities of animals and plants &#8211; is perhaps the simplest process in which to track changes in the ecology of species in response to climate change&#8221; (IPCC 2007). PEP725, the Pan-European Phenological Database, is thought as a European research infrastructure to promote and facilitate phenological research. Its main objective is to build up and maintain a European-wide phenological database with an open, unrestricted data access for science, research and education. So far, 20 European meteorological services and 6 partners from different phenological network operators have joined PEP725. The PEP725 phenological data base (www.pep725.eu) now offers close to 13 million phenological observations, essentially starting with 1951, comprising more than 200 species and 69 growing stages based on the BBCH scale. The data base grows with about 100000 additional observations per year. Having accepted the PEP725 data policy and finished the registration, the data can be downloaded according to various criteria, e.g. by a specific plant or all data from one country.To date (January 2023) we could count at least 115 peer - reviewed publications based on the PEP725, 17 of them published in Nature and one in Science. It appears that new avenues are entered in plant phenological research. Since remote sensing technology has been making big leaps forward with improved instruments and increasing resolution, Land Surface Phenology (LSP) is exploring its capabilities, especially experimenting with new and improved methods to correlate LSP with Ground Phenology (GP). A small but very active community continues to produce high quality research on plant physiological mechanisms and their relation with the atmospheric environment. Prominent appears the increase in the number of atmospheric variables, which have been related with plant phenology, for instance atmospheric brightening, light pollution, humidity, wind, day-time versus night-time trends. Strong interdisciplinarity combined with an increasing range of topics characterise the recent developments in phenological research. Just to cite a few: phenology in a future climate, agrometeorological questions, the role of plant energy budget, climate warming and fruit phenology, winter warming versus spring phenology, drought effects on phenology, carbon cycle, temperature sensitivity of various phenological phases and many more.Download statistics and the rapidly growing number of PEP725 based publications demonstrate the great demand and potential of the PEP725 phenological data set, which urgently needs development including a facilitated access, gridded versions and near real time products to attract a greater range of users.Finally, we would invite all, who have already used PEP725, to give us feedback!!! (markus.ungersboeck@geosphere.at; helfried.scheifinger@geosphere.at)Reference: Intergovernmental Panel on Climate Change (IPCC). 2007. Climate Change 2007: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.