Tree stand dynamics, changes in the ground vegetation and soils, and species diversity of wood-decaying fungi were studied in pristine middle boreal spruce forests affected by a surface fire in the Vodlozersky National Park (Arkhangelsk Region, Russia) in 2011. In the third year after the fire, the burnt area was dominated by birch, which contributed an average of 72% to the total amount of major tree species regeneration. In sites affected by a high-severity fire, the ground vegetation cover did not exceed 40%, with Chamaenerion angustifolium (L.) Scop. and Marchantia polymorpha L. dominating in the first years after. By the tenth year, the diversity of the newly forming tree layer increased from 5 to 11 species and natural thinning of deciduous tree regeneration was already underway, although its amount was still over 100,000 plants per hectare throughout. By the end of the first post-fire decade, Picea abies (L.) H. Karst. and Pinus sylvestris L. accounted for 11% of the total regeneration. The occurrence and cover of pyrogenic species Chamaenerion angustifolium and Marchantia polymorpha declined sharply at this stage. Vegetation in sites affected by mid-severity fire was mostly regenerating through propagation of the survivor Avenella flexuosa (L.) Drejer, Vaccinium myrtillus L., V. vitis-idaea, etc. In the burnt area, the species diversity of wood-destroying fungi was reduced compared to the adjacent unburned areas, and it was the same in both heavily and moderately burnt areas. This is probably due to the fact that the downed deadwood in post-fire sites was trunks of the same age and in the same degree of decay whereas the total amount of downed deadwood in the control (unburnt forest) was lower but featuring all stages of decay and, furthermore, there were plenty of fungi-populated dead standing and weakened overmature trees.

Новые для Карелии виды сосудистых растений

Новые и редкие для флоры Карелии виды сосудистых растений

Приводится информация о восьми новых и трёх редких для Карелии заносных видах растений. Acer pseudoplatanus, Crataegus maximowiczii и Prunus maackii, обнаруженные в естественных лесах в окрестностях Ботанического сада Петрозаводского университета, вероятно, преодолели первый этап натурализации и могут быть отнесены, как минимум, к потенциально инвазивным видам, особенно Prunus maackii, отмеченный в количестве многих десятков особей. Обнаружение в республике Alchemilla cheirochlora, A. integribasis, A. parcipila и A. trichocrater существенно расширяет представление о вторичном ареале этих видов, которые вплоть до недавнего времени были известны в центральной части Европейской России и восточнее, иногда из немногих пунктов. Непреднамеренно занесенный на территорию республики Amaranthus blitum найден в России в самой северной точке ареала. Находка довольно широко культивируемого в Республике Antirrhinum majus в дикорастущем состоянии как случайно занесенного растения была только делом времени. Появление Citrullus lanatus и Cucumis melo связано с необыкновенно теплыми для Карелии погодными условиями летом и в начале осени 2018 г., что способствовало активному отдыху населения на природе и, как следствие, появлению семян в местах отдыха, а также их прорастанию в течение того же вегетационного периода. Четыре последних вида, несомненно, являются эфемерофитами. Обсуждаются возможные пути, способы и время заноса каждого вида.

Recreation digression of forest ecosystems in the heritage site “White Sea Petroglyphs” was studied for the first time. This site is a compact system of rock outcrops partially cleared of forest vegetation, which bear Neolithic rock carvings (petroglyphs), and are linked together by walking trails. Patterns have been identified in the transformation of soils, plant cover components (tree stand, tree seedlings, understory and living ground cover), as well as fine roots (within 3 mm in diameter) of woody species under the recreation impact. Trampling was found to deform and destroy the top soil horizons, entailing a significant loss of the forest floor thickness and organic matter stores. Overall, the flora of the area is quite well preserved; 95–100 % of which is represented by native species. The living ground cover is noticeably damaged in the most actively used sites (fragments of trails and vista points). They feature a poor species composition, shrinking of the herb-dwarf shrub and moss-lichen cover, and a low percent cover of grassland and ruderal species. Easily accessible and actively visited sites have no or reducing amounts of tree seedlings, the tree stand is damaged and forest regeneration is hampered – the number of viable seedlings is minimal (100 pcs/ha). The mass of roots below 3 mm in diameter in heavily trampled trails showed a reduction of up to 74 %, while the root saturation in less affected trails slightly increased. Recreation transformations of the plant communities have not resulted in a loss of their resilience so far. The recreational digression in the studied sites was classified into stages I–III (weakly disturbed – strongly disturbed). Function zoning of the area should be modified using recreation-tolerant communities more intensively in order to reduce recreation impact. The most damaged areas, which are losing their stability, should be excluded from active use by modification of walking trails and building additional boardwalks.