Gabriela Bujalska-Grüm (1936–2020)

mal ecology, specialist in the population ecology of rodents, was an outstanding person in Polish science and well known worldwide. After accomplishing her studies on the University of Warsaw, Faculty of Biology, she began her scientific work in the Institute of Ecology of Polish Academy of Science in 1960 and she tied her entire professional career with this institution. Only after the Institute ceased to operate in 2003, she spent the last few years before retirement with the Cardinal Stefan Wyszyński University in Warsaw. Her approach to the population ecology, as she herself admitted (Bujalska 2003), came from the tradition of the “Warsaw school of ecology” created in the late 50’ of 20 century by professors K. Tarwid and K. Petrusewicz, representing the holistic views on ecological systems. Population processes were considered to be a function of the population structures, such as sex ratio, age or spatial structures or social hierarchy, which limited and modified direct impact of the changing environment (Petrusewicz 1965). At the end of 70’ and in 80’, however, a reductionist approach became dominant in ecology, deriving the properties of a population from the properties of individuals that differ from each other genetically and in many other ways (Łomnicki 1978). This view has become evident in the later works of Gabriela. Her recognition in science, Gabriela owed to the results of studies on ecology of small forest rodent – the bank vole Clethrionomys glareolus (or Myodes glareolus), which she carried out for many years on a small island in the Masurian Lakeland, northern Poland. The Crabapple Island, 4 hectares in size, inhabited by the bank vole became a “live laboratory” with 37-year-long history of research. At first in 1965, the team of scientists from the Institute of Ecology began and had carried out for a decade their studies on population productivity and dynamics as a part of the worldwide research program, known as IBP. Then, Gabriela continued her own research in many aspects of ecology of this population for another three decades. Such long-term studies are extremely valuable in times of fast climate change, as they allow us to capture the effects of the change for different components of the Nature. The impressive effect of this research is one hundred and several dozen of papers published by Gabriela, of which 102 papers appeared in journals registered by the Web of Science (all databases) and were cited 1131 times (1062 without self citations) so far. Her other papers, usually overlooked by the international statistics, include published conference abstracts and many popular science and review articles, short notes, book reviews etc, written in Polish for domestic readers. In most of her published papers, she was the only author. Her greatest success was discovering the territoriality among mature female bank voles. (Earlier only males of some rodent species were considered to be territorial). Moreover, she concluded that if the territory was the prerequisite for gaining puberty, the number of breeding females was strictly limited by the space available to the local population; and so was the reproduction rate of the population (Bujalska 1970, 1973). Her papers, published in international journals, met quickly with great interest of specialists, who immediately begun checking whether females were territorial also in other rodent populations. Soon it turned out that female territoriality occurs in all bank vole species (Bujalska 1985), but only rarely in other voles. This sparked an interesting discussion on the function of the breeding territory in female rodents and on the background for differences in the spacing behaviour among microtine species. Its echoes can still be heard in the polemical articles published e.g. in Trends of Ecology and Evolution or on discussion Forum of Oikos (Ostfeld 1990, 1991, Bujalska 1991, Wolff 1993). In her papers based on data from the island, professor Bujalska investigated many other ecological problems, such as productivity of the population (Petrusewicz et al. 1971), the cyclicity in OBITUARY