An assessment of disturbance effects on plant cover of Numto natural park (Khanty-Mansiysk autonomous okrug – Ugra)

The Numto Natural Park, Khanty-Mansi Autono-mous Okrug - Yugra, Russia, has recently attracted the attention of environmental organizations due to oil extraction operations in its territory. This paper presents the study of the vegetation cover dynamics and the assessment of natural and anthropogenic disturbances of Numto’s ecosystems. Due to the development of oil deposits, more than 60 adventitious plant species arrived to the park, and the synan-thropization index reached 26.4%. Tree rings showed the predominant influence of the climatic and pyrogenic components on the growth of trees. The technogenic impact that had occurred in the 1990s gave a spasmodic increase in cedar growth in the disturbed areas in the form of abnormal hard streaks. Later on, the impact of technogenic factors on the wood growth waned. Satellite imagery helped to determine changes in the vegetation cover. From 2011 to 2018, the area of disturbed sites doubled while the length of infield roads and pipelines increased by 5.7 times. The area of burnt fire sites increased manifold; how-ever, fires occurred at a considerable distance from the oil extraction sites and were of natural origin. Currently, the disturbed ecosystems, including burnt fire sites and fire-damaged ecosystems, occupy 2.1% of the oil deposits area, and the area of pyrogenic disturbances is larger than the area of technogenic ones. Compared to the oil and gas fields in the adjacent areas, the level of disturbance in the Numto Natural Park can be considered low. Since deer pastures were not disturbed by the oil extraction operations, the traditional nature management remains possible. Further oil field development requires ongoing monitoring of the ecosystem condition.