The Calluna life cycle concept revisited: implications for heathland management

Heather, Calluna vulgaris, is a key species of European dry heath and central determinant of its conservation status. The established Calluna life cycle concept describes four phases—pioneer, building, mature, and degeneration—distinguishable by growth and vitality characteristics of undisturbed plants grown from seeds. However, little is known about the life cycle and ageing of plants subjected to severe disturbance, although measures to this effect (burning, mowing) are common in heathland management. We studied the vitality of over 400 heather plants by examining multiple morphological (plant height, long shoot and inflorescence lengths, flowering activity), anatomical (growth rings) and environmental (management, nitrogen deposition, climate) attributes. We found Calluna vitality to be mainly determined by the aboveground stem age, and that severe disturbances promote vigorous vegetative regeneration. Ageing-related shifts in the habit and vitality of plants resprouting from stem-base buds is similar to that of seed-based plants, but the former revealed higher vitality when young, at the cost of a shorter life span. In contrast, plants originating from decumbent stems resemble building-stage plants but apparently lack the capacity to re-enter a cycle including stages other than degeneration-type. As a consequence, we supplemented the established heather life cycle concept with a post-disturbance regeneration cycle of plants derived from resprouting. We conclude that management of dry lowland heathlands should include rotational small-scale severe disturbance to support both seed germination and seedling establishment as well as vegetative regeneration chiefly of young heather plants capable of resprouting from buds near rootstock.

Betula pendula Roth. natural regeneration in forest-steppe zone of Tatarstan Republic

A direct dependence of the birch coppice regeneration on the diameter of the tree trunk, felling age, forest growth conditions, seed regeneration, soil and climatic conditions and the degree of soil mineralization has been revealed. It was found that after the dying of a 30-year-old birch due to a drought in 2010, coppice shoots appeared in 10 % of the trees on the studied area. The reasons for vegetative regeneration have been determined, which mainly occurs by the degree of thickness in trees with a trunk diameter of up to 22 cm, or by the category of state in dead wood (70 % of the total number of coppice). The absence of seed birch undergrowth in drying birch plantations was found as a result of the tremendous soil ramping and the predominance of small-leaved lime, aspen undergrowth, Norway maple of seed origin, and seed origin oak, which requires tending. For successful birch seed regeneration under favorable climatic conditions, it is recommended to carry out soil mineralization of at least 50 % of the total area. When carrying out vegetative propagation, it is necessary to cut birch no older than 40 years, and in case of useful properties loss in birch forests over 71 years old in protective forests, we recommend the use of clear cutting but not selective cutting. Keywords: natural renewal, hanging birch, undergrowth, logging, Republic of Tatarstan

Recovery of Forest Vegetation in a Burnt Area in the Republic of Korea: A Perspective Based on Sentinel-2 Data

Forest fires are severe disasters that cause significant damage in the Republic of Korea and the entire world, and an effort is being made to prevent forest fires internationally. The Republic of Korea budgets 3.38 million USD every year to prevent forest fires. However, an average of 430 wildfires occur nationwide annually. Thirty-eight percent of the forest fire budget is used for forest restoration. Restoring afforestation in the affected areas is a top priority. This study aimed to estimate the degree of vegetative regeneration using the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Soil-Adjustment Vegetation Index (SAVI), and Normalized Burn Ratio (NBR). Although many studies have used NBR with NDVI to extract plant regeneration regions, they suffer from atmospheric effects and soil brightness. Thus, this study utilizes NBR with NDVI, EVI, and SAVI to accurately select areas for targeted forest restoration. Furthermore, this study applies clustering analysis to extract the spatial boundary of vegetative regenerative regions. The proposed method suggests a pixel range of vegetation indices. These ranges can be used as an indicator, such as the NBR’s Fire Severity Level, which reflects the mountain’s local characteristics, meaning that it can be useful after forest fires. Using the three vegetation indices can extract more accurate vegetation areas than using NBR with NDVI and can help determine a forest restoration target area.

Productivity of long-term swards on drainage lands of the Non-Chernozem region

В статье представлены результаты исследований формирования продуктивности бобово-злаковых травосмесей, созданных с участием самовозобновляющихся видов трав: полевицы гигантской ВИК 2, мятлика лугового Балин и овсяницы красной Максима. Исследования 2018–2019 годов показали, что данные травы обладают высоким потенциалом вегетативного возобновления. По обеспеченности побегами и шильцами на второй год жизни отличилась овсяница красная: 320–600 шт./м2— на естественном фоне произрастания и 320–680 шт./м2 — при внесении минеральных удобрений в дозе N45Р45К45. Обеспеченность почками возобновления у исследуемых видов трав превосходила количество побегов в 2,0–2,1 раза на неудобренных и 2,3–2,7 раза — на фоне удобрений. Преобладание почек возобновления над побегами указывает на высокую приспособленность видов к длительному вегетативному возобновлению в данных условиях. Высокие показатели органов возобновления отмечены у мятлика лугового — 2,1–2,7 и овсяницы красной — 2,0–2,7. Коэффициент реализации почек (отношение побегов к почкам, выраженное в процентах) наиболее высоким был у неудобренных трав — 48,8–50,0%. Установлено, что неудобренные травостои 1-го года пользования, созданные на основе низовых злаков, сформировали 14,2–18,1 т/га зелёной массы. Продуктивность травостоев с полевицей составляла в среднем 16,2 т/га, с мятликом — 15,3 т/га, с овсяницей красной — 15,7 т/га зелёной массы. Травосмеси, в составе которых был райграс пастбищный, обеспечивали меньшую продуктивность — 14,2–15,2 т/га, что на 2,4–2,7 т/га меньше по сравнению с травостоями с овсяницей тростниковой (16,6–18,1 т/га). Значительных изменений урожайности травостоев от вида бобового компонента (люцерны изменчивой и лядвенца рогатого) не установлено. Внесение удобрений способствовало росту продуктивности самовозобновляющихся травостоев. Урожайность зелёной массы и сбор сухого вещества увеличились в 2 раза. Наибольшую продуктивность на фоне удобрений обеспечили травостои с мятликом луговым — 3,60–4,70 тыс. корм. ед. Наименее продуктивными были травостои с полевицей гигантской — 3,57–4,42 т/га. The article reports on the productivity of legume-gramineous swards of “VIK 2” giant bentgrass, “Balin” bluegrass, and “Maksim” red fescue. The research conducted in 2018–2019 proved high potential of these species to vegetative regeneration. Red fescue developed a lot of shoots and seedlings in the second life cycle: 320–600 pcs/m2 — without fertilization and 320–680 pcs/m2— when applying N45Р45К45. Plants formed more buds than shoots showing good adaptability to a long-term vegetative regeneration. Bud number of bluegrass and red fescue exceeded the shoot number by 2.1–2.7 and 2.0–2.7 times, respectively. Unfertilized plants showed the highest bud formation coefficient — 48.8–50.0%. Low-growing grasses produced 14.2–18.1 t ha-1of green mass under no fertilization in the first year. Bentgrass swards yielded 16.2 t ha-1 of green mass, bluegrass — 15.3 t ha-1, red fescue — 15.7 t ha-1. Perennial ryegrass mixtures had the lowest productivity (14.2–15.2 t ha-1) while tall fescue provided 16.6–18.1 t ha-1. Legume component insignificantly affected stand productivity. Fertilization improved crop performance. Green mass and dry matter yields increased by 2 times. Fertilized bluegrass ecosystems performed the best yielding 3.60–4.70 thousand feed units. Bentgrass swards gave the lowest yield of 3.57–4.42 t ha-1.

Recent decline in vegetative regeneration of bamboo (Yushania alpina), a key food plant for primates in Volcanoes National Park, Rwanda

The African montane bamboo Yushania alpina provides both habitat and food for many species in the Albertine Rift region. In Volcanoes National Park (VNP), Rwanda, it is especially important as a key food resource for the Endangered mountain gorilla Gorilla beringei beringei and Endangered golden guenon Cercopithecus mitis kandti. We examined temporal and spatial variation in bamboo shoots regeneration and consumption by primates, monitored between 2013 and 2018 in 82 16-m2 plots located along transects in VNP. Our analyses revealed a decline in vegetative regeneration of bamboo in recent years, which is mirrored by a decline in bamboo shoot consumption by primates; but an increase in proportional intake. Local declines in regeneration are potentially due to high intensities of herbivory, decreased amounts of rainfall during growing seasons, and natural processes that form part of the life cycle of bamboo. Moreover, spatial variation in bamboo regeneration can be explained by elevation, as well as by stand-level variation in soil acidity, vegetation density, and the density of dead bamboo culms. We discuss the potential mechanisms underlying observed temporal and spatial variations and outline possible effects of a decline in bamboo regeneration for primates and other aspects of biodiversity in VNP.

Fire and legacy effects of logging on understorey assemblages in wet-sclerophyll forests

Wet sclerophyll forests of south-eastern Australia typically experience wildfire once or twice a century. However, disturbance regimes have changed drastically in recent decades due to clear-fell logging and altered fire regimes. To date, botanical research on disturbances in wet-forests has focussed on individual elements of disturbance regimes, such as intensity, at single points in time, largely neglecting past disturbance history. Studies of the impact of previous disturbance history on plant responses to successive disturbance events are important to our understanding of vegetation dynamics. Here we investigate the response of wet-forest understorey species to two important elements of disturbance regimes – timing and type – and trajectories of change in these vegetation communities. In surveys separated by 15 years over 128 sites, we recorded the frequency of occurrence of 21 understorey species from stands with disturbance histories ranging from 4 years post clear-fell logging to 150 years post wildfire. Approximately half our sites were burnt in the 2009 Black Saturday wildfires. This provided an opportunity to examine the effects of inter-fire interval and the legacy effects of clear-fell logging. Generalised linear mixed modelling showed that many of the species studied appear to be at risk of population decline as a result of clear-fell logging. Unlike wildfire, clear-fell logging led to changes in the understorey, having a long-lasting impact on the presence of key wet-forest taxa that rely on vegetative regeneration. These include large shade-bearing shrubs like Hedycarya angustifolia R.Cunn., Bedfordia arborescens Hochr. and Olearia argophylla (Labill.) Benth., which were resilient to recurrent wildfire but responded negatively to recent wildfire in sites with a history of clear-fell logging. Negative effects of a short inter-fire interval were limited to a few species.

Abundance of liana species in an Amazonian forest of Brazil reflects neither adventitious root nor foliar sprout production

Liana abundance and size have increased in neotropical forests. High vegetative reproductive capacity (clonality) may be the cause of high abundance in some liana species. Correlations between vegetative propagation capacity and (1) relative abundance of liana species, (2) rooting and foliar sprouting potentials of congeneric species, and (3) phylogenetic position were determined. Species selection was based on the relative abundance of lianas in ten 0.5-ha parcels in continuous forest within the Biological Dynamics of Forest Fragments Project (BDFFP), Brazil. Five individuals per species were replicated with seven cuttings per individual. Cuttings placed in moistened sand and coconut fibre were observed for 5 mo in a humid greenhouse. Survival percentage, rooting percentage, potential regeneration index and longest root length were determined per species. The two most abundant species (9.3% and 4.1% relative abundance) had low vegetative regeneration capacity, contrary to expectations. However, a significant, positive relationship between vegetative propagation and relative abundance of liana species whose relative abundances were <4% was found. Congeneric species showed no difference in vegetative propagation between rare and abundant species, except congeners of Machaerium. Vegetative reproductive capacity occurred in all major evolutionary lineages, but was highest in Fabaceae and Bignoniaceae, families of high abundance both locally and broadly across Neotropical forests.