Grass Communities Research Articles

Greenhouse Gas Emissions from a 20-Year-Old Restored Peatland

Peatlands are ecosystems with unique hydrological and ecological properties that serve as critical carbon reservoirs, helping facilitate the reduction of greenhouse gases (GHG). In Canada, the peat industry uses vacuum harvesting to extract peat for horticultural use. This disturbs the natural ecosystem, increasing CO2 and decreasing CH4 emissions due to complete removal of surface vegetation and lowering of the water table. Following years of extraction, if these peatlands are not properly restored, GHG emissions will increase, negatively impacting the climate. The moss layer transfer technique (MLTT) is the primary method for restoring peatlands in Canada. The MLTT allows peatlands to regain their natural ecosystem function and to reaccumulate peat. This is done by revegetation of key species including sphagnum moss, and rewetting of the peatland through the blockage of drainage ditches. My research project investigates a peatland in Pointe-Lebel, Quebec restored in 2004 using MLTT following vacuum extraction. I used the closed chamber method to measure the CO2 and CH4 exchanges at the plant community scale and three repetitions of each of moss, shrubs, and cotton grass communities were followed throughout the summer. Wells at each collar provided the water table depth; a controlling variable for GHG fluxes. I conducted a vegetation survey at peak plant productivity to characterize the proportions of the plant communities and to allow chamber measurements of GHG to be scaled by the contribution of each plant community. If successful, a restored peatland will be a net sink of carbon. Preliminary data analysis at this 20-year-old restored site indicates a net CO2 sink during the summer of 2024. My data also suggests that the site is a small source of CH4. The results from my project will aid in advancing research on peatlands, stressing the importance of taking the proper steps towards restoration.

A juhlegeltetési módok hatása a gyepen felvételezhető endoparazita populációra

Sampling for the occurrence of internal parasites of sheep was carried out in three extensively cultivated Achilleo - Festucetum pseudovinae grass communities with different grazing systems but with the same site conditions, in 2022 - 2023, at the MATE Research Institute in Karcag, Hungary. The sheep grazing regimes studied were: pastoral grazing, rotational grazing, and permanent, delta - forest grazing used on all grazing days. Microscopic analysis of the genomes and numbers of potentially infective oviposition and L3 larval stage endoparasites in sheep pastures was carried out on samples of faecal matter from grazed pastures and grass samples prepared using a 'larval feeder'. Our research objective was to clarify the effect of different sheep grazing practices on parasite infestation in a semi - natural grassland community with a solonyec soil composition.

Effects of Seasonal Variation on Nitrogen Use in Brazilian Cerrado Grass Communities

In savanna ecosystems, the seasonal effects of nitrogen forms and availability, as well as their utilization by plants, influence the abundance and distribution of herbaceous species in grassland communities. This study examines seasonal effects on nitrogen availability and utilization by native grass species in the Cerrado, a savanna ecosystem in Brazil. Ammonium and nitrate levels in soil, nitrate acquisition and transport, and Nitrate Reductase Activity (NRA) in different plant parts during dry and wet periods were assessed. Results indicated higher soil nitrate availability during the wet period, influenced by precipitation, with leaves showing a higher nitrate content compared to roots. There was seasonal modulation in nitrate reduction, with leaves being the primary site during the dry period and roots during the wet period. The studied grass species exhibited heterogeneous responses to seasonal nitrogen availability, potentially affecting community abundance patterns. Findings suggest that edaphoclimatic seasonality plays a crucial role in nitrogen distribution and utilization capacity by grass plants in the Cerrado, contributing to the understanding of these ecosystems’ ecology.

ОСОБО ОХРАНЯЕМЫЕ ПРИРОДНЫЕ ТЕРРИТОРИИ В КОНТЕКСТЕ ГОРОДСКОГО ПЛАНИРОВАНИЯ ГОРОДА ПЕРМИ: ФУНКЦИИ И ПРОБЛЕМЫ

This article is a study using GIS technologies aimed at assessing and analyzing changes in the areas of types of plant communities under the influence of oil and gas industry facilities on the island. Sakhalin.
 Purpose (Object): The purpose of this study is to assess the degree of change in the areas of types of plant communities under the influence of oil and gas indus-try facilities on the island. Sakhalin.
 Methods: Methodology for assessing changes in the areas of plant communi-ties under the influence of oil and gas industry facilities on the island. Sakhalin in-cludes 7 stages, consisting of spatial reference of a raster image (vegetation map of the island) to a base map, as well as the subsequent creation of polygonal objects based on the received data and conducting spatial analysis in ArcGIS software. The final stage involves determining the degree of change using specified criteria.
 Findings: Most of the types of plant communities on Sakhalin Island belong to the conditionally unmodified class with the percentage of the territory occupied by oil and gas industry facilities less than 0.5%. We assigned the following types of plant communities to this class: white birch-larch grass-shrub forests in place of dark coniferous forests (0.00%); reed grass communities in place of green moss and grassy dark coniferous forests (0.17%); etc. The weakly modified class in-cludes 4 types of communities: larch mid-taiga lichen forests with dwarf cedar (0.75%); thickets of wild rosemary in place of larch green moss-ledum forests (0.74%); larch mid-taiga green moss-ledum forests (0.69%); thickets of dwarf ce-dar and alder (0.59%). None of the existing types of plant communities on Sakhalin Island belongs to the moderately or highly modified class, since the area of land occupied by oil and gas industry facilities does not exceed 2%.
 Conclusions: Assessment of the degree of change in areas occupied by various types of plant communities under the influence of oil and gas industry facilities on the island. Sakhalin makes it possible to determine the most disturbed types of communities and classify them according to the degree of change.
 This information is useful in view of the relevance of the issue of environmental pollution by oil and gas industry facilities, as well as from the point of view of the possibility of developing measures to protect and protect the environment. In addi-tion, based on the data obtained, it is possible to predict further changes in the de-velopment of Sakhalin shelf projects and the construction of new onshore infra-structure.

Testing prescribed burning to shift an agronomic grass community to a diverse native plant community

Prescribed burning can be an effective land management tool. Here, we study changes in plant diversity and composition following experimental fire disturbance in microcosm units extracted from a twenty-five-year-old historically reclaimed grassland located at Highland Valley Copper mine in British Columbia (B.C.), Canada. Experimental microcosm units were dominated by agronomic grass species Elymus lanceolatus, Thinopyrum intermedium and Bromus inermis. The disturbance treatment was fire intensity, represented by three levels (light, moderate, and heavy), replicated six times per treatment. Fire intensity was controlled by modifying the weight of dried litter applied to each microcosm unit (50 g,150 g, 200g), along with the time each grass turf was burned (10 s, 15 s, 20 s). One day after the fire treatment was applied, microcosm units were seeded with a native species mix consisting of six grassland species common to southern B.C. to examine effectiveness of plant establishment postburn. Disturbance treatments resulted in higher overall alpha diversity, richness, evenness, and beta diversity. Plant community changes included colonization of seeded native forbs, grasses, and legumes in response to disturbance. Aboveground net primary productivity (ANPP) was net neutral within the light and moderate burning disturbance treatments but resulted in increased ANPP with heavy disturbance. Litter mass reduced plant diversity and ANPP, indicating that litter was a major factor in plant community dynamics. These results suggest disturbance by burning leads to short term positive plant community response towards increasing diversity of semi-arid grasslands, and aids in shifting plant communities to higher diversity composed of an increase in native plant species. Our results also suggest that without active management the gains observed in native species establishment might quickly be out shadowed and restricted by the previously dominant agronomic plant community.

Effects of Warming and Elevated CO2 on Stomatal Conductance and Chlorophyll Fluorescence of C3 and C4 Coastal Wetland Species

Coastal wetland communities provide valuable ecosystem services such as erosion prevention, soil accretion, and essential habitat for coastal wildlife, but are some of the most vulnerable to the threats of climate change. This work investigates the combined effects of two climate stressors, elevated temperature (ambient, + 1.7 °C, + 3.4 °C, and 5.1 °C) and elevated CO2 (eCO2), on leaf physiological traits of dominant salt marsh plant species. The research took place at the Salt Marsh Accretion Response to Temperature eXperiment (SMARTX) at the Smithsonian Environmental Research Center, which includes two plant communities: a C3 sedge community and a C4 grass community. Here we present data collected over five years on rates of stomatal conductance (gs), quantum efficiency of PSII photochemistry (Fv/Fm), and rates of electron transport (ETRmax). We found that both warming and eCO2 caused declines in all traits, but the warming effects were greater for the C3 sedge. This species showed a strong negative stomatal response to warming in 2017 and 2018 (28% and 17% reduction, respectively in + 5.1 °C). However, in later years the negative response to warming was dampened to < 7%, indicating that S. americanus was able to partially acclimate to the warming over time. In 2022, we found that sedges growing in the combined + 5.1 °C eCO2 plots exhibited more significant declines in gs, Fv/Fm, and ETRmax than in either treatment individually. These results are important for predicting future trends in growth of wetland species, which serve as a large carbon sink that may help mitigate the effects of climate change.

Home‐field advantage, N‐priming and precipitation independently govern litter decomposition in a plant diversity manipulation

Abstract Litter decomposition facilitates the recycling of often limiting resources, which may promote plant productivity responses to diversity, that is, overyielding. However, the direct relationship between decomposition, k, and overyielding remains underexplored in grassland diversity manipulations. We test whether local adaptation of microbes, that is, home‐field advantage (HFA), N‐priming from plant inputs or precipitation drive decomposition and whether decomposition generates overyielding. Within a grassland diversity‐manipulation, altering plant richness (1, 2, 3 and 6 species), composition (communities composed of plants from a single‐family or multiple‐families) and precipitation (50% and 150% ambient growing season precipitation), we conducted a litter decomposition experiment. In spring 2020, we deployed four replicate switchgrass, Panicum virgatum, litter bags (1.59 mm mesh opening), collecting them over 7 months to estimate litter k. Precipitation was a strong, independent driver of decomposition. Switchgrass decomposition accelerated with grass richness and decelerated as phylogenetic dissimilarity from switchgrass increased, suggesting decomposition is fastest at ‘home’. However, decomposition slowed with switchgrass density. In plots that contained switchgrass, we observed no relationship between decomposition and fungal saprotroph dissimilarity from switchgrass. However, in plots without switchgrass, decomposition slowed with increasing saprotroph dissimilarity from switchgrass. Combined these findings suggest that HFA is strongest when closely related neighbours, that is, heterospecific neighbours, are present in the community, rather than other individuals of the same species, that is, conspecifics. Legumes accelerated decomposition with more litter N remaining in those plots, suggesting that N‐inputs from planted legumes are priming decomposition of litter C. However, decomposition and overyielding were unrelated in legume communities. While in grass communities, overyielding and decomposition were positively related and the relationship was strongest in plots with low densities of switchgrass, that is, with heterospecific neighbours. Combined these findings suggest that plant species richness and community composition stimulate litter decomposition through multiple mechanisms, including N‐priming, but only HFA from local adaptation of microbes on closely related species correlates with overyielding, likely through resource recycling. Our results link diversity with ecosystem processes facilitating above‐ground productivity. Whether diversity loss will affect litter decomposition, productivity or both is contingent on resident plant traits and whether a locally adapted soil microbiome is maintained. Read the free Plain Language Summary for this article on the Journal blog.

Dynamics of Seed Productivity of the Endemic Species Anemonastrum biarmiense (Juz.) Holub (Ranunculaceae) in the South Ural Reserve

Five-year dynamics of seed productivity of the high-mountain endemic species Anemonastrum biarmiense (Juz.) Holub in the territory of the South Ural Reserve is presented. The collection of seed material was carried out in three cenopopulations (Dunan-Sungan, Yusha and Naratash), two of which are associated with tall grass communities of the Polygonion krascheninnikovii Kashapov 1985 union, the third cenopopulation is part of the tundra-like communities of the spruce-birch crooked forest of the Calamagrostion arundinaceae (Luquet 1926) Oberdorfer 1957 union. A brief description of the weather conditions of the growing year is given with a graph of minimum temperatures from May to July 2015–2021, where the largest number of days with frost was noted for 2017 (9 days), and not noted at all for 2021. A description of the morphological heterogeneity is given. Seeds of A.biarmiense, while it was found that the seeds of plants are most often characterized by an ellipsoidal shape, less often an ellipsoidal one with a base narrowed into a stem. The spherical shape of the seeds is more common in forest cenopopulations, and the ellipsoidal shape is more common in meadow ones. Seeds with a wavy and even edge are observed equally often. The metric and quantitative parameters of A. biarmiense seed productivity in natural cenopopulations from 2015 to 2021 are given. Most of the metrics increase in 2016, 2018 and decrease in 2015, 2017 with worsening weather conditions. Among the quantitative indicators, the largest number of ovules and seeds per seedling, fl ower-bearing shoot and individual were found in the meadow cenopopulations of Yusha, Dunan-sungan of the forest belt, and in the Naratash CP of the subalpine belt, their number is reduced. Accordingly, a higher seed productivity coeffi cient was found in the open meadow communities of the forest belt, and a lower one in the crooked forest belt. Characterizing the weather conditions of the growing year, most of the maximum values were found in 2016, when the climatic conditions were the most favorable during the growing season. The minimum values of seed productivity indicators were noted in 2017 and 2021, characterized by the least favorable weather conditions throughout the growing season. The lowest variability of seed productivity traits was found for the length and width of the seed, the highest – for the weight of seeds and the number of unfulfilled seeds per seed, flowering shoot and plant. The amplitude of variability for all studied parameters of seed productivity varies in a wide range among the observed cenopopulations in the belt of spruce crooked forests on the ridge. Naratash, while in the narrowest range, variation of signs in the Yusha and Dunan-sungan CP was revealed.

Does chronic nitrogen deposition have effects on grass physiology of natural habitats?

Anthropogenic activities increase nitrogen deposition, which can have major consequences for biodiversity and ecosystem function. We experimentally investigated how a community of grass species would respond to three levels of nitrogen enrichment, considering their biomass and efficiency of photosynthesis. The experiments were conducted in an open savanna area with sparse trees (cerrado sensu stricto). Fifteen plots were divided considering high nitrogen supplementation, low nitrogen supplementation, and control (without nitrogen application) as treatments. The nitrogen dosages applied in each treatment were based on deposition estimates for 2050 in the Cerrado biome. Three native species had their photosynthetic metabolism evaluated 45 days after the last supplementation. Except for Echinolaena inflexa, all the 16 species found in the area expressed C4 metabolism. Echinolaena inflexa and Loudetiopsis chrysothrix showed an increase in leaf nitrogen with supplementation, with differences in chloroplastidic pigment contents. Differently from L. chrysothrix which increased its chlorophyll content, E. inflexa showed a decrease in chlorophyll and carotenoid contents under N supplementation. E. inflexa is a small species and its leaf expansion under higher contents of nitrogen suggests that this species was affected by shading caused by other community species that increased their biomass. Supplemental nitrogen did not affect the efficiency of photosynthesis of these species or severely change the grass community biomass. However, we noted only a tendency for higher biomass and biomass per tiller for Urochloa decumbens, which suggests a concern about exotic species' performance under conditions of greater availability of nitrogen.

Atmospheric drying and soil drying: Differential effects on grass community composition

AbstractGlobal surface temperatures are projected to increase in the future; this will modify regional precipitation regimes and increase global atmospheric drying. Despite many drought studies examining the consequences of reduced precipitation, there are few experimental studies exploring plant responses to atmospheric drying via relative humidity and vapor pressure deficit (VPD). We examined eight native California perennial grass species grown in pots in a greenhouse in Los Angeles, California for 34 weeks. All pots were well‐watered for 21 weeks, at which point we reduced watering to zero and recorded daily growth and dormancy for 3 weeks. We used this information to better understand the drought tolerance of our species in a larger soil drying × atmospheric drying experiment. In this larger experiment, we grew all eight species together in outdoor mesocosms and measured changes in community composition after 4 years of growth. Soil drying in our small pot experiment mirrored compositional shifts in the larger experiment. Namely, our most drought‐tolerant species in our pot experiment was Poa secunda, due to a summer dormancy strategy. Similarly, the grass community shifted toward P. secunda in the driest soils as P. secunda was mostly unaffected by either soil drying or atmospheric drying. We found that some species responded strongly to soil drying (Elymus glaucus, Festuca idahoensis, and Hordeum b. californicum), while others responded strongly to atmospheric drying (Bromus carinatus and Stipa cernua). As result, community composition shifted in different and interacting ways in response to soil drying, atmospheric drying, and their combination. Further study of community responses to increasing atmospheric aridity is an essential next step to predicting the future consequences of climate change.

Оценка перспектив сельскохозяйственного использования биологического ресурса лугово-пастбищных биоценозов Воронежской области

Highly productive meadow grass communities are a valuable biological resource used in agricultural production. To date, there are several main forms of using natural meadows in agriculture – this is haymaking and grazing. The paper presents the results of a comparative analysis of the biological production of aboveground phytomass of four representative sites of floodplain meadows located in Semiluksky, Ternovsky, Talovsky and Bogucharsky districts of the Voronezh region. The study covers a five-year period from 2019 to 2023. The results of the study show differences in the peak values of the aboveground plant biomass of meadows in different regions of the region, as well as the difference in the timing of the formation of the maximum biomass from the beginning of spring vegetation. Based on the results of the study, conclusions are drawn about the prospects of using the biological resource of meadow phytocenoses in the agricultural production of the region, as well as its scaling. Keywords: BIOLOGICAL RESOURCE OF MEADOW BIOCENOSES, DYNAMIC OF PRODUCTIVITY OF MEADOW BIOCENOSES, REMOTE MONITORING, FEED AND ENERGY VALUE

Effects of grass functional diversity on invasion success by exotic grasses in Cerrado grasslands

Abstract Invasive species pose significant challenges to successful restoration efforts worldwide. A strategy to reduce invasions is to establish communities consisting of species with varied ecological strategies. These strategies typically align along the conservative and plant size axes, and more recently, along a below‐ground collaboration axis. However, we lack understanding of how the diverse ecological strategies of Cerrado grass species, their combinations and their interactions with soil conditions can mitigate invasions. Here, we investigated how native grass communities composed by species with different ecological strategies affect the invasion success in two soil types of abandoned pastures in the Cerrado. Specifically, we tested the hypothesis that greater above‐ and below‐ground functional diversity reduces exotic species invasion. We also evaluated whether the isolated effects of native species on invasion were positive or negative. We installed an experiment with species richness ranging from zero to eight native grass species. In November 2019, we sowed species combinations to create communities composed by species with different ecological strategies. We quantified the above‐ground biomass of exotic species as a measure of invasion. To characterize the species ecological strategies, we measured five functional traits. Functional diversity of maximum height and specific root length (SRL) had the highest predictive power; however, the most parsimonious model included only SRL diversity, which represents the collaboration axis. Native above‐ground biomass was also negatively related to exotic species biomass. Furthermore, invasion was greater in less stressful soil conditions but did not interact with diversity. The effect of native species varied from facilitation to competition, with the annual fast‐growing native species favouring invasion. Synthesis and applications. Our results show that greater functional diversity of combined above‐ and below‐ground traits reduces invasion success, shedding light on an underexplored role of specific root length diversity. The competitive and facilitative effects of different native species highlight the need for careful selection of the species to be used in restoration programmes. Furthermore, the absence of interaction between diversity and soil types highlights the need for an integrated management of the functional composition and edaphic factors to increase resistance to invasion in these Neotropical grass communities.

Overgrazing effects on seasonal variations in availability of palatable grasses in the foraging grounds of blackbucks Antilope cervicapra

Despite the diverse and wide-ranging forage availability in abundance in grassland habitat systems, wild ungulates perform selective grazing under their natural foraging conditions as an adaptation to the variation in palatability and availability of forage grasses in different seasons in a given area by retaining the less palatable species as the dry season diet. The study elucidated how the domestic livestock exerts overgrazing pressures on the grass community, removing all the grass stand before the arrival of dry season and restricting forage availability for blackbucks Antilope cervicapra in Basur Amruth Mahal Kaval Conservation Reserve, Karnataka. Direct observations on the feeding behaviours of herbivores were done and opportunistic sampling for the collection and identification of grasses at the same time, covering all different microhabitat characteristic locations of the grassland in all seasons. 29 grass species were identified with different palatability grades and variations in their seasonal availability as forage. Dichanthium annulatum (Forssk.) Stapf and Sehima nervosum (Rottler) Stapf with the highest palatability grade, are spatially declining with the increase of less palatable grasses in the Kaval i.e. Heteropogon contortus (L.) P.Beauv. ex Roem. & Schult. and Chrysopogon fulvus (Spreng.) Chiov under overgrazing pressures. A limitation of three to four months shortage of forage grass availability was created under overgrazing pressures by domestic livestock when compared to selective grazing expectations by blackbucks throughout the year. The forage grasses were grazed to empty by domestic livestock before the arrival of dry seasons. In prolonged overgrazing effects, a competitive replacement of palatable grasses by unpalatable or less palatable species can be expected in these grasslands. Competitive exclusion of blackbucks by the domestic herbivores was modelled using Lotka-Volterra equations. The model revealed that the populations of wild boar and domestic herbivores tend to increase up to their carrying capacities K2 with time ti and attain stable populations, but the blackbuck populations tend to extinction with continuous exposure to competition due to their shy nature. The grass composition can be expected to recover with palatable grasses only if external grazing forces are controlled or avoided.

Eastern redcedar roots create legacy effects that suppresses growth of prairie species.

The expansion of woody species from their historical ranges into grasslands is a global problem. Understanding the mechanisms that enable species to successfully establish and then re-encroach following their removal is critical to effectively managing problem species. Legacy effects are a mechanism that could be critical to the reestablishment of woody encroachers following their removal. Legacy effects occur when a species alters the biotic and abiotic environment in a way that affects communities that establish subsequently. In this study, we assess whether the eastern redcedar (Juniperus virginiana), a North American woody encroacher, generates legacy effects that affect communities that establish following removal of this species from an experimental grass community. We conducted a series of experiments to evaluate the effects of J. virginiana, roots on the germination and growth of grasses and to determine if the effects of root-addition treatments were derived from a microbial or allelopathic origin. Aqueous extracts of J. virginiana roots were found to inhibit the germination of grasses. We found escalating suppression of overall community biomass and the biomass of each individual species with increasing root treatments. Finally, we determined the origin of the observed suppressive effect is unlikely to be of microbial origin. Synthesis: Our results suggest that J. virginiana exudes an allelochemical into soils that inhibits the growth of certain grasses and thus has the potential to have legacy effects on future occupants. We suggest that the inhibition of the development of grasses in areas where J. virginiana has been removed is a mechanism that may favor the reestablishment of J. virginiana. Our results indicate the legacy effects of J. virginiana must be considered when conducting removal and restoration of J. virginiana infested lands.

Plant diversity and grasses increase root biomass in a rainfall and grassland diversity manipulation

The loss of plant productivity with declining diversity is well established, exceeding other global change drivers including drought. These patterns are most clearly established for aboveground productivity, it remains poorly understood whether productivity increases associated with diversity are replicated belowground. To address this gap, we established a plant diversity-manipulation experiment in 2018. It is a full factorial manipulation of plant species richness and community composition, and precipitation. Three and five years post-establishment, two bulk soil cores (20cm depth) were collected and composited from each plot and were processed for roots to determine belowground biomass as root standing crop. We observed a strong positive relationship between richness and aboveground production and belowground biomass, generating positive combined above and belowground with diversity. Root standing crop increased 1.4-fold from years three to five. Grass communities produced more root biomass (monoculture mean 463.9 ± 410.3g m−2), and the magnitude of the relationship between richness and root standing crop was greatest within those communities. Legume communities produced the fewest roots (monoculture mean 212.2 ± 155.1g m−2), and belowground standing crop was not affected by diversity. Root standing crops in year three were 1.8 times higher under low precipitation conditions, while in year five we observed comparable root standing crops between precipitation treatments. Plant family was a strong mediator of increased belowground biomass observed with diversity, with single family grass and aster families generating 1.7 times greater root standing crops in six compared to single species communities, relationships between diversity and aboveground production were consistently observed in both single-family and multiple family communities. Diverse communities with species from multiple families generated only 1.3 times the root standing crop compared to monoculture average root biomass. We surprisingly observe diverse single family communities can generate increases in root standing crops that exceed those generated by diverse multiple family communities, highlighting the importance of plant richness within plant family for a given community. These patterns have potential implications for understanding the interactions of multiple global change drivers as changes in both precipitation and plant community composition do alter whether plant production aboveground is translated belowground biomass.

Invasibility of Common Plant Community Types of the Middle Urals

This paper specifies the invasibility of common plant community types in the natural habitats of the Middle Urals. Invasibility was defined as the vulnerability of a community to alien plant species invasions, regardless of the conditions in which the community existed. We analyzed 749 vegetation relevés made in natural bogs, floodplains, rocky grasslands, meadows, and forest communities. We surveyed urban and non-urban habitats (30–40 km from the city). Invasibility was calculated in two different ways based on two parameters: the number and proportion of alien species in the relevé. These invasibility parameters are widely applicable and comparable, scale-independent, measurable, and reliable, based on data that do not require the destruction of ecosystems or biota and are based on available data. Based on the invasibility degree, we identified three community-type groups with two subgroups in one group. In ascending order of invasibility degree, the community types were arranged as follows: (1) bogs with and without trees; (2a) coniferous forests; grass communities in floodplains; (2b) deciduous forests, coniferous plantations, floodplain communities with woody plants; and (3) dry meadows and rocky grasslands. Obtained results of the assessment of different plant community invasibility may be used to understand patterns of alien plant distribution in local habitats and the reasons for the different vulnerability of communities to plant invasions.

Wildfires in the Larch Range within Permafrost, Siberia

Throughout the larch range, warming leads to frequent fires and an increase in burned areas. We test the hypothesis that fires are an essential natural factor that reset larch regeneration and support the existence of larch forests. The study area included Larix sibirica and L. gmelinii ranges within the permafrost zone. We used satellite-derived and field data, dendrochronology, and climate variables analysis. We found that warming led to an increase in fire frequency and intensity, mean, and extreme (&gt;10,000 ha) burned areas. The burned area is increasing in the northward direction, while fire frequency is decreasing. The fire rate exponentially increases with decreasing soil moisture and increasing air temperature and air drought. We found a contrasting effect of wildfire on regeneration within continuous permafrost and within the southern lowland boundary of the larch range. In the first case, burnt areas regenerated via abounded larch seedlings (up to 500,000+ per ha), whereas the south burns regenerated mostly via broadleaf species or turned into grass communities. After the fire, vegetation GPP was restored to pre-fire levels within 3–15 years, which may indicate that larch forests continue to serve as carbon stock. At the southern edge of the larch range, an amplified fire rate led to the transformation of larch forests into grass and shrub communities. We suggested that the thawing of continuous permafrost would lead to shrinking larch-dominance in the south. Data obtained indicated that recurrent fires are a prerequisite for larch forests’ successful regeneration and resilience within continuous permafrost. It is therefore not necessary to suppress all fires within the zone of larch dominance. Instead, we must focus fire suppression on areas of high natural, social, and economic importance, permitting fires to burn in vast, larch-dominant permafrost landscapes.

Ecosystem resilience to invasion and drought: Insights after 24 years in a rare never-grazed grassland.

Understanding the resilience of ecosystems globally is hampered by the complex and interacting drivers of change characteristic of the Anthropocene. This is true for drylands of the western US, where widespread alteration of disturbance regimes and spread of invasive non-native species occurred with westward expansion during the 1800s, including the introduction of domestic livestock and spread of Bromus tectorum, an invasive non-native annual grass. In addition, this region has experienced a multi-decadal drought not seen for at least 1200 years with potentially large and interacting impacts on native plant communities. Here, we present 24 years of twice-annual plant cover monitoring (1997-2021) from a semiarid grassland never grazed by domestic livestock but subject to a patchy invasion of B. tectorum beginning in ~1994, compare our findings to surveys done in 1967, and examine potential climate drivers of plant community changes. We found a significant warming trend in the study area, with more than 75% of study year temperatures being warmer than average (1966-2021). We observed a native perennial grass community with high resilience to climate forcings with cover values like those in 1967. In invaded patches, B. tectorum cover was greatest in the early years of this study (1997-2001; ~20%-40%) but was subsequently constrained by climate and subtle variation in soils, with limited evidence of long-term impacts to native vegetation, contradicting earlier studies. Our ability to predict year-to-year variation in functional group and species cover with climate metrics varied, with a 12-month integrated index and fall and winter patterns appearing most important. However, declines to near zero live cover in recent years in response to regional drought intensification leave questions regarding the resiliency of intact grasslands to ongoing aridification and whether the vegetation observations reported here may be a leading indicator of impending change in this protected ecosystem.

History of vegetation and fires in the Arctic part of the Pur-Taz interfluve in the Holocene

The global climate change and significantly increased anthropogenic pressure on the Arctic and Subarctic regions require modern ecosystem monitoring and understanding of the past environmental changes. Vegetation history is reflected by pollen spectra recorded in peat deposits, investigation of which is one of the main methods in the research of long-term climatic changes. In order to reconstruct the vegetation and fire history of today’s south tundra in the lower reaches of the Taz river, we carried out palynological exploration of peat and underlying lake sediments covering the last 11.2 cal ka BP in the Tazovsky district of the Yamalo-Nenets Autonomous Okrug (Russia). In the course of the research, we found 31 pollen taxa, 4 taxa of spore plants, 2 types of fungal spores, one species of shell amoeba and green algae. We have identified several stages in the development of the local wetland biocenosis at the study site and reconstructed the history of changes in the vegetation cover of the region, including changes in the composition of the woody vegetation. Grasslands, with groups of trees among thickets of shrubs and lake-mire complexes dominated in the study area by 11.2 cal ka BP. The grasslands were gradually supplemented by wet grass communities, which were then replaced by swamps and tundra complexes in the mid-Holocene. The time periods of the local fires have been established. The fire that had the greatest effect on the vegetation at the study site was detected in the period of 8.1 cal ka BP. We have revealed periods of the least fire activity – 7.6–5.5 cal ka BP and the highest fire activity – 12.5–8 cal ka BP.

Effect of isolated lactic acid bacteria on the quality and bacterial diversity of native grass silage.

The objective of this study was to isolate lactic acid bacteria (LAB) from native grasses and naturally fermented silages, determine their identity, and assess their effects on silage quality and bacterial communities of the native grasses of three steppe types fermented for 60 days. Among the 58 isolated LAB strains, Limosilactobacillus fermentum (BL1) and Latilactobacillus graminis (BL5) were identified using 16S rRNA sequences. Both strains showed normal growth at 15- 45°C temperature, 3-6.5% NaCl concentration, and pH 4-9. Two isolated LAB strains (labeled L1 and L5) and two commercial additives (Lactiplantibacillus plantarum and Lentilactobacillus buchneri; designated as LP and LB, respectively) were added individually to native grasses of three steppe types (meadow steppe, MS; typical steppe, TS; desert steppe, DS), and measured after 60 d of fermentation. The fresh material (FM) of different steppe types was treated with LAB (1 × 105 colony forming units/g fresh weight) or distilled water (control treatment [CK]). Compared with CK, the LAB treatment showed favorable effects on all three steppe types, i.e., reduced pH and increased water-soluble carbohydrate content, by modulating the microbiota. The lowest pH was found in the L5 treatment of three steppe types, at the same time, the markedly (p < 0.05) elevated acetic acid (AA) concentration was detected in the L1 and LB treatment. The composition of bacterial community in native grass silage shifted from Pantoea agglomerans and Rosenbergiella nectarea to Lentilactobacillus buchneri at the species level. The abundance of Lentilactobacillus buchneri and Lactiplantibacillus plantarum increased significantly in L1, L5, LP, and LB treatments, respectively, compared with CK (p < 0.05). In summary, the addition of LAB led to the shifted of microbiota and modified the quality of silage, and L. fermentum and L. graminis improved the performance of native grass silage.