Biodiversity conservation in the Bialowieza Forest in the context of natural and anthropogenic disturbances dynamics

The paper presents the issue of conservation of species diversity of the Białowieża Forest in the context of both natural and human−related disturbances. These disturbances, in the authors’ opinion, were the main factor that shaped the unique species diversity of this area. Examples of natural disturbances occurring in the Białowieża Forest include the impact of wind, insect outbreaks and, to a lesser extent, fires. On the other hand anthropogenic disturbances are related to various forms of forest use, which historically took place here, i.e. grazing by domestic animals, beekeeping, charcoal production, and recently also forest management. Currently, in the situation of rarity and unpredictability of natural disturbances, as well as due to a significant decrease in human impact on forests of the Białowieża Forest, there is a risk of decrease of biodiversity, which is related to the process of natural succession, homogenization of the forest and the decline of favourable habitats for the development of some organisms. This particularly applies to the so−called ‘open forest’ species that are dependent on sunny places in forests. Historically these species found favourable conditions in the Białowieża Forest in many sites, where traditional forms of forest use took place, but also in areas used for traditional forest management. At present, it is necessary to adapt forest management on the one hand and nature conservation on the other, in order to meet the requirements of diverse groups of organisms, both requiring passive as well as active methods of conservation. The authors postulate the necessity of introducing a diverse conservation strategy in the Białowieża Forest

The effect of temperature and humidity changes on insects development their impact on forest ecosystems in the context of expected climate change

Ongoing climate change is mainly evident as increased in average temperature. It is expected to have a significant impact on world's biomes, with forest ecosystems especially vulnerable to these changes. The effect of climate change on forests is both indirect, through its impact on various tree species of different ecological requirements, and direct, through its impact on all living components of the forest ecosystem. Among the latter, insects are the group of the greatest importance, including species detrimental to forest health. The impact of climate change on forest insects may be reflected in their distribution, phenology, activity, number of generations and, indirectly, through impact on their natural enemies. Predicting the future direction and pace of the climate change, as well as direct and indirect consequences of its effect on forest insects is difficult and often subject to considerable inaccuracy. The paper presents a review of data from the published literature in this area of study. The influence of the basic climate parameters, temperature and humidity, on forest herbivore insects is discussed, particularly in the context of the most probable scenarios of climate change, i.e. the gradual increase in the average temperature. Observed and projected impacts of climate change in relation to the influence of herbivorous insects on forest ecosystems are characterized. We present some of the possible adaptation strategies of forest management to the expected climate changes

Flower chafer Protaetia speciosissima (Scopoli, 1786) (Coleoptera: Scarabaeidae) – protected saproxylic species of oak stands in Poland

The paper presents the results of our studies on the preferences of the flower chafer, Protaetia speciosissima (Scopoli, 1786). The studies were carried out in 2009-2010 in the Forest Districts of Hajnówka, Krotoszyn, Łochów, Piñczów, and Puławy, located in various regions of Poland. Barrier traps consisting of a Moericke's trap and a Malaise's trap combined with a barrier of fine net were used to collect beetles. Traps were installed at two heights in over 100 years old oak stands, with the upper level in the canopy layer (mean height of 20.5 m) and the lower level adjacent to the tree trunk (mean height of 4,5 m). During two-year study, we collected a total of 328 specimens of P. speciosissima, 299 from the upper- and 29 from the lower forest layer. Thus, we confirmed strong preferences of the adult of P. speciosissima for the canopy layer in oak stands. Furthermore, our observations on phenology indicate that the second half of June and all of July are the months with the highest population density of P. speciosissima. This paper also proposes modes of action for conservation of the species

Problem of a massive dying-off of Norway spruce stands in the 'Bialowieza Forest' Forest Promotional Complex

The Białowieża Forest (BF) is in many respects an exceptional object, of a great importance for nature protection and forest management, at the international scale. The BF plays also a key role from the point of view of regional development and welfare of local community. In the last period, a big threat for multiple values of the BF has arisen, as a result of enormous bark beetle infestation, which started in 2012 and has killed 1.4 million m3 of spruce trees. In the paper, first, a brief overview of the general history of the BF and an account of long−term human impacts on its functioning and structure is provided. Next, the history of bark beetle infestations in the BF is analysed. It is shown that, in the period 1992−2007, the average volume of spruces killed by bark beetle amounted on average to 20,000 m3 of wood annually. During that period practically all dead trees were removed from the forest by means of salvation cuttings. Starting from 2008, more and more trees infested by European spruce bark beetle were left in the forest, in a result of a pressure exerted by environmental groups. In 2012, Minister of Environment decided to reduce the allowable cut, determined in forest management plans elaborated for the managed part of the BF, from 107,000 to 48,500 m3/year. This decision, along with several other regulations and restrictions, made in practice impossible to stop the development of a current bark beetle infestation, which started in 2011 and intensified during the next 6 years (solely in 2016 bark beetles killed 480,000 m3 of spruce trees). In the paper, the most important implications and consequences of the current situation are briefly summarized and discussed. A special attention is given to the problems concerning: 1) protection of Natura 2000 species and sites (endangered by bark beetle outbreak), 2) a negative influence of large amounts of spruce deadwood on forest soils, 3) threats caused by pathogenic fungi, 4) question of public safety, 5) fire hazard, and 6) economical dimension. The legal and socio−economical foundations of the functioning of Hajnówka, Browsk and Białowieża forest districts comprising the managed part of the BF, as well as their most important environmental and social consequences are discussed too. Among others, it is indicated that, under current conditions of the BF, human intervention plays a key role in maintaining stable and compositionally diverse woodland communities. Finally, several suggestions and recommendations are provided, aimed at, in the short term, breaking off the current bark beetle outbreak, and, in the long term, at maintaining a multifunctional character of the BF and its ability to provide all important ecosystem services on a sustainable basis