Hydrological Droughts in the Białowieża Primeval Forest, Poland, in the Years 1951–2020

Leszek Hejduk,Michał Wasilewicz,Ewa Kaznowska,Agnieszka Hejduk

doi:10.3390/f12121744

Leszek Hejduk, Michał Wasilewicz + Show 2 more

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https://doi.org/10.3390/f12121744

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Abstract

The occurrence of hydrological drought, caused by rainfall deficiency, poses a threat to forest areas—not only due to the danger of fire, but as a result of changes in habitat conditions. It is predicted that more frequent periods of drought and high temperatures will reduce the stability of forests and increase their susceptibility to industrial pollution, pressure from insect pests, fungal pathogens, and fires. The main aim of this study was to investigate the current streamflow droughts in the catchment area of the Narewka River as an indicator of hydrological droughts in the Białowieża Primeval Forest for the period 1951–2020. The research presented in this paper shows that low flows of surface waters have appeared as an indicator of hydrological droughts almost every year since 1983. The analysis of the trend over the past 70 years shows that the aggregated annual volumes of low flows and the number of days with low flows are increasing significantly. This indicates a significant and relatively permanent change in the seasonal structure of the river runoff in the event of low summer flow.

Highlights

The expected impact of climate change on the outflow of rivers in the Vistula River basin indicates the predominance of increases in low and high flows. These results suggest that future hydrological droughts may be less severe than today, while the risk of flooding may increase
The main aim of this study was to investigate the current streamflow droughts in the catchment area of the Narewka River as an indicator of hydrological droughts in the Białowieza Primeval Forest, and to establish whether the disturbing changes observed in thermal anomalies [1] and the structure of precipitation [24] apply to the region of the Białowieza Primeval Forest
In recent years, the low flows of the Narewka River have been characterized by greater intensity and severity concerning their long-term average values, and whether they show the direction of changes in the outflow regime from the Białowieza Primeval Forest or, on the contrary, whether the results show that the low-flow outflow regime of the studied area is resilient despite the observed climate changes

Summary

Introduction

Thermal Anomalies and Frequency of Hydrological Droughts. One of the manifestations of modern climate warming is significant changes in the frequency of thermal anomalies. In Poland, as in the rest of Europe, asymmetric warming is being observed. This is caused more by an increase in the frequency of anomalously warm months than by the decrease in anomalously cold months [1]. In Poland, periodic droughts with deep low flows of rivers, as well as floods, are characteristic of this climate. The frequency and intensity of droughts is increasing, and climate change in Poland manifests to the greatest extent in the temperature and heat stress records [3,4].

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