Dominant Vegetation Types Research Articles

Climate-driven peatlands development and vegetation dynamics in Northeastern China since the mid-Holocene: New evidence from Huanan peatlands

Studying peatland evolution and vegetation patterns in response to climate change provides valuable insights into future ecosystem trends. This study focuses on the Huanan peatland located in Changbai Mountain regions in Northeast China, utilizing phytolith analysis and stable carbon isotope composition (δ13C) to reconstruct late Holocene vegetation dynamics. Additionally, grain size, total organic carbon (TOC), and total nitrogen (TN) analyses were conducted to understand peatland development and paleoclimate since the late Holocene. The research identifies three distinct climate periods since 5500 cal yr BP: an initial warm, humid phase (5500–4000 cal yr BP) characterized by high river levels that formed lacustrine sediments; a subsequent transition to cold, dry conditions (4000–1500 cal yr BP) that initiated peat formation; and continued dry, cold conditions (1500 cal yr BP to the present) with sustained peat growth. Phytolith data reveal a dominant forest vegetation type since 2000 cal yr BP, further divided into three periods: 2000–1300 cal yr BP, marked by diverse and dense vegetation; 1300–750 cal yr BP, with declining plant cover; and 750 cal yr BP to the present, characterized by an increase in woody plants but a reduction in local grass cover.

Spatiotemporal patterns and drivers of extreme fire severity in Spain for the period 1985–2018

Extreme fire severity patterns driven by climate change have deep consequences on vegetation, subsequent fire regimes and have consequences on the effectiveness of extinction. In this work, we aimed to determine if extreme fire severity defined as the 90th percentile of RdNBR has changed in Spain in the last 3 decades, if extreme fire severity patterns have differed among the different vegetation types and what drivers have influenced extreme fire severity in both summer and non-summer fires. We have used perimeters of large wildfires (≥100 ha, n = 1719) from 1985 to 2018 in four pyroregions and the main dominant vegetation types. We have analyzed time series for each pyroregion and vegetation type to determine if there were significant trends and breakpoints in extreme fire severity. We have also analyzed the effects of drought, weather, topography and vegetation on extreme fire severity in seasonal wildfires.Extreme fire severity increased in summer fires from 1985 to 2018, especially in the East and North pyroregions, while the Southwest pyroregion reached highest values in summer. There has been an increase of severity in shrubland, mosaic vegetation and conifer forests in summer. Broadleaved forests had the lowest values of fire severity and did not show any trend in the period considered. The most important drivers of extreme fire severity are, in order of importance, pyroregion, elevation, slope, vapor pressure deficit (VPD) and vegetation type for summer fires, and VPD, vegetation types, pyroregion, windspeed and drought for non-summer fires. Global change is increasing climate-related events. Our results indicate that extreme fire severity in summer has been on the rise in recent decades in Spain, suggesting that, in a climate warming context, without strategic management of these increasingly flammable landscapes, further increases may be likely.

Independent and interactive effects of N and P additions on foliar P fractions in evergreen forests of southern China

Fertilization or atmospheric deposition of nitrogen (N) and phosphorus (P) to terrestrial ecosystems can alter soil N (P) availability and the nature of nutrient limitation for plant growth. Changing the allocation of leaf P fractions is potentially an adaptive strategy for plants to cope with soil N (P) availability and nutrient-limiting conditions. However, the impact of the interactions between imbalanced anthropogenic N and P inputs on the concentrations and allocation proportions of leaf P fractions in forest woody plants remains elusive. We conducted a meta-analysis of data about the concentrations and allocation proportions of leaf P fractions, specifically associated with individual and combined additions of N and P in evergreen forests, the dominant vegetation type in southern China where the primary productivity is usually considered limited by P. This assessment allowed us to quantitatively evaluate the effects of N and P additions alone and interactively on leaf P allocation and use strategies. Nitrogen addition (exacerbating P limitation) reduced the concentrations of leaf total P and of different leaf P fractions. Nitrogen addition reduced the allocation to leaf metabolic P but increased the allocation to other fractions, while P addition showed opposite trends. The simultaneous additions of N and P showed an antagonistic (mutual suppression) effect on the concentrations of leaf P fractions, but an additive (summary) effect on the allocation proportions of leaf P fractions. These results highlight the importance of strategies of leaf P fraction allocation in forest plants under changes in environmental nutrient availability. Importantly, our study identified critical interactions associated with combined N and P inputs that affect leaf P fractions, thus aiding in predicting plant acclimation strategies in the context of intensifying and imbalanced anthropogenic nutrient inputs.

Hierarchical-modular framework for habitat mapping through systematic and informed integration of remote sensing data with contextual information

Accurate and up-to-date habitat maps at national or regional levels are critical for informing conservation and restoration actions. Land cover maps generated from Earth Observation (EO) data can, to varying degrees, indicate the extent of some habitat categories but these are often insufficient in terms of the level of detail required. This study introduces a hierarchical-modular framework based on the globally applicable Food and Agriculture Organization (FAO) Land Cover Classification System (LCCS) whereby the land cover classes can be systematically translated to habitat categories and further differentiated by referencing contextual information and expert knowledge. Application is showcased for Wales (United Kingdom) where 10 m spatial resolution land cover maps were first constructed nationally from time-series of Sentinel-1C-band radar and Sentinel-2 optical data (2018–2020). The contextual datasets derived from non-EO sources were utilised to associate dominant vegetation types to detailed habitat classes.The accuracy assessment done using field survey data highlights that habitat classes directly derived from EO, including cultivated/managed and forest types, demonstrated higher mapping accuracies (>70% User's and Producer's Accuracies) compared to those that were more heavily dependent on non-EO-derived contextual information. These included neutral grasslands and fen/marsh/swamp that demonstrated lower accuracies (<20%) but also other detailed wetland classes (user's and producer's accuracies ranging from 25 to 60%). These reduced accuracies were largely associated with discrepancies in the contextual datasets used for their differentiation and mapping, and those integrated within field validation datasets. Dependency on contextual datasets diminished as detailed habitat maps were generalized into broader categories. The study proposes that, for enhanced habitat mapping, efforts should focus not only on EO data but also on maximising the accuracy and minimizing inconsistencies in contextual datasets as well as taxonomical systems. The flexible structure of the FAO LCCS hierarchical framework is also highlighted, emphasizing its adaptability for future improvements in habitat mapping by incorporating contextual datasets and more advanced algorithms that can improve EO-derived land cover descriptions.

Aspect Differences in Vegetation Type Drive Higher Evapotranspiration on a Pole‐Facing Slope in a California Oak Savanna

AbstractQuantifying evapotranspiration (ET) is critical to accurately predict vegetation health, groundwater recharge, and streamflow generation. Hillslope aspect, the direction a hillslope faces, results in variable incoming solar radiation and subsequent vegetation water use that drive ET. Previous work in watersheds with a single dominant vegetation type (e.g., trees) have shown that equator‐facing slopes (EFS) have higher ET compared to pole‐facing slopes (PFS) due to higher evaporative demand. However, it remains unclear how differences in vegetation type (i.e., grasses and trees) influence ET and water partitioning between hillslopes with opposing aspects. Here, we quantified ET and root‐zone water storage deficits between a PFS and EFS with contrasting vegetation types within central coastal California. Our results suggest that the cooler PFS with oak trees has higher ET than the warmer EFS with grasses, which is counter to previous work in landscapes with a singule dominant vegetation type. Our root‐zone water storage deficit calculations indicate that the PFS has a higher subsurface storage deficit and a larger seasonal dry down than the EFS. This aspect difference in subsurface water storage deficits may influence the subsequent replenishment of dynamic water storage, groundwater recharge and streamflow generation. In addition, larger subsurface water deficits on PFS may reduce their ability to serve as hydrologic refugia for oaks during multi‐year droughts. This research provides a novel integration of field‐based and remotely‐sensed estimates of ET required to properly quantify hillslope‐scale water balances. These findings emphasize the importance of resolving hillslope‐scale vegetation structure within Earth system models, especially in landscapes with diverse vegetation types.

Effect of highway greenbelt constrution on groundwater flow in a semi-arid region.

The highway greenbelt, vigorously promoted in arid and semi-arid areas, has obvious impacts on beautifying the environment, absorbing dust, reducing noise, and maintaining soil and water. Moreover, it affects the characteristics of how water resources are distributed and the regional groundwater cycle. However, the impact of highway greenbelt construction on groundwater flow in semi-arid areas is unknown. The Hubao Highway greenbelt in the north part of the Tumochuan Plain was studied as an example. The paper combines field investigation, remote sensing and mathematical modeling to quantify the impact of highway green space construction on regional groundwater circulation. The results showed that: Trees, shrubs and grasses were the dominant vegetation types in the landscaped area, accounting for 42.17% of the studied area. The total evapotranspiration water consumption of the green belt during the growing season was 471.35 × 104m3. The groundwater recharge in the study area was mainly derived from the lateral recharge in front of the mountain, and the main discharge was the evapotranspiration water consumption of the green belt. This evapotranspiration accounts for 3.31% of the total groundwater recharge. Under the condition that the recharge in front of the mountain remains constant, the evapotranspiration water consumption of the green belt will still have an increasing trend in the future. Appropriate planting of poplar and other high water-consuming trees may be the best way to mitigate the adverse effects of greenbelt evapotranspiration on groundwater resources. The results of this study provide valuable insights for environmental protection and infrastructure development in similar areas.

On the Botany of Manas Wild Life Sanctuary in Assam

The Manas Wild Life Sanctuary (26°30'-27°N and 91°-92°E) falls under the 'Tiger Project' area of Assam. The area is covered chiefly by dry or moist deciduous forests ; tall grasses grow on vast areas and provide cover for rich wild life.Tne paper enumerates 383 species of phanerogams, collected during three botanical excursions. There are about 90 tree species in the area, and same number of shrubs and undershrubs. The composition of the flora and dominant vegetation types are briefly discussed.

Reconstruction of zonal vegetation of East Asia in the early Eocene

For the fi rst time, unifi ed types of zonal vegetation are established for the early Eocene in east of Asia and their changes in space are traced. The reconstruction is based on the analysis of 48 palynofl oras from the early Eocene localities situated from 75 to 19° N using Integrated Plant Record (IPR) vegetation analysis. In the results, quantitative parameters of the relative proportions of vegetation components are obtained. According to our data, along the latitudinal gradient from north to south, there is an increase in evergreen plants and herbs, but a decrease in conifers and deciduous plants, and no changes in the proportions of xerophytic plants. Mixed mesophytic forest is a widespread and dominant type of zonal vegetation. In general, the main changes in plant biomes show a very shallow and weakly pronounced diff erentiation into two plant zones: mixed mesophytic forest, north of ~50° paleolatitude, and warmer types of zonal vegetation (broadleaved evergreen forest and an ecotone between mixed mesophytic and broadleaved evergreen forests), in addition to mixed mesophytic forest, south of ~50° paleolatitude. The resulting spatial patterns of vegetation are consistent with climatic inferences.

Peatland evaporation across hemispheres: contrasting controls and sensitivity to climate warming driven by plant functional types

Abstract. Peatlands store disproportionally large amounts of carbon per unit area, a function that is dependent on maintaining high and stable water tables. Climate change is likely to negatively impact carbon storage in peatlands, in part due to increases in vapour pressure deficit (VPD) driving higher evaporation (E) rates. However, the response of E to increasing VPD depends on the dominant vegetation type within peatlands. In this study, we used multiple years of eddy covariance (EC) measurements to compare E regimes at two peatlands with contrasting vegetation types – Kopuatai bog in Aotearoa / New Zealand, dominated by the vascular wire rush Empodisma robustum, and Mer Bleue bog in Canada, a “typical” shrub- and moss-dominated Northern Hemisphere peatland. We examined seasonal variability in E and equilibrium E (Eeq), energy balance partitioning, and the response of E, evaporative fraction (EF), and canopy conductance (gc) to VPD. Mean annual E was 45 % lower than mean annual Eeq at Kopuatai but only 16 % lower at Mer Bleue, demonstrating much greater limitations on E at Kopuatai. In addition, the mean midday (10:00–14:30 local standard time) dry-canopy Bowen ratio (β) at Kopuatai was 2.0 compared to 0.8 at Mer Bleue; therefore, the sensible heat flux (H) dominated over the latent heat flux (LE) at Kopuatai and vice versa at Mer Bleue. The responses of E, EF, and gc to increasing VPD at Kopuatai demonstrated stronger limitations on evaporative water loss for VPD &gt; 0.7 kPa compared to Mer Bleue. The observed limitations at Kopuatai were attributed to strong stomatal control by E. robustum due to the rapid decrease in gc with increasing VPD; however, surface E could also be limited by its dense standing litter. At Mer Bleue, however, E was only weakly limited at VPD &gt; 2 kPa, likely due to weak stomatal control over transpiration by the sparse shrub canopy and relatively large surface E from Sphagnum carpets. As such, the results of this study suggest that E. robustum drives a greater “hydrological resistance” to increasing VPD than the vegetation at Mer Bleue, leading to greater water retention at Kopuatai. This may enable greater resilience of the carbon sink function at Kopuatai to climatic warming and drying than at Mer Bleue.

Invasive-dominated grasslands in Hawai'i are resilient to disturbance.

Non-native-dominated landscapes may arise from invasion by competitive plant species, disturbance and invasion of early-colonizing species, or some combination of these. Without knowing site history, however, it is difficult to predict how native or non-native communities will reassemble after disturbance events. Given increasing disturbance levels across anthropogenically impacted landscapes, predictive understanding of these patterns is important. We asked how disturbance affected community assembly in six invaded habitat types common in dryland, grazed landscapes on Island of Hawai'i. We mechanically disturbed 100 m2 plots in six vegetation types dominated by one of four invasive perennial grasses (Cenchrus ciliaris, Cenchrus clandestinus, Cenchrus setaceus, or Melinis repens), a native shrub (Dodonaea viscosa), or a native perennial bunchgrass (Eragrostis atropioides). We censused vegetation before disturbance and monitored woody plant colonization and herbaceous cover for 21 months following the disturbance, categorizing species as competitors, colonizers, or a combination, based on recovery patterns. In addition, we planted individuals of the native shrub and bunchgrass and monitored survival to overcome dispersal limitation of native species when exploring these patterns. We found that the dominant vegetation types showed variation in post-disturbance syndrome, and that the variation in colonizer versus competitor syndrome occurred both between species, but also within species among different vegetation types. Although there were flushes of native shrub seedlings, these did not survive to 21 months within invaded habitats, probably due to regrowth by competitive invasive grasses. Similarly, survival of planted native individuals was related to the rate of regrowth by dominant species. Regardless of colonization/competitor syndrome, however, all dominant vegetation types were relatively resilient to change. Our results highlight that the altered post-agricultural, invaded grassland landscapes in Hawai'i are stable states. More generally, they point to the importance of resident communities and their effects on species interactions and seed availability in shaping plant community response to disturbance.

Variations in species diversity patterns and community assembly rules among vegetation types in the karst landscape.

The various vegetation types in the karst landscape have been considered the results of heterogeneous habitats. However, the lack of a comprehensive understanding of regional biodiversity patterns and the underlying ecological processes limits further research on ecological management. This study established forest dynamic plots (FDPs) of the dominant vegetation types (shrubland, SL; mixed tree and shrub forest, MTSF; coniferous forest, CF; coniferous broadleaf mixed forest, CBMF; and broadleaf forest, BF) in the karst landscape and quantified the species diversity patterns and potential ecological processes. The results showed that in terms of diversity patterns, the evenness and species richness of the CF community were significantly lower than other vegetation types, while the BF community had the highest species richness. The other three vegetation types showed no significant variation in species richness and evenness. However, when controlling the number of individuals of FDPs, the rarefied species richness showed significant differences and ranked as BF > SL > MTSF > CBMF > CF, highlighting the importance of considering the impacts of abundance. Additionally, the community assembly of climax communities (CF or BF) was dominated by stochastic processes such as species dispersal or species formation, whereas deterministic processes (habitat filtering) dominated the secondary forests (SL, MTSF, and CBMF). These findings proved that community assembly differs mainly between the climax community and other communities. Hence, it is crucial to consider the biodiversity and of the potential underlying ecological processes together when studying regional ecology and management, particularly in heterogeneous ecosystems.

Fire‐Induced Carbon Loss and Tree Mortality in Siberian Larch Forests

AbstractClimate change is intensifying the fire regime across Siberia, with the potential to alter carbon combustion and post‐fire carbon re‐accumulation trajectories. Few field‐based estimates of fire severity (e.g., carbon combustion and tree mortality) exist in Siberian larch forests (Larix spp.), which limits our ability to project how an intensified fire regime will affect regional and global climate feedbacks. Here, we present field‐based estimates of fire‐induced tree mortality and carbon loss in eastern Siberian larch forests. Our results suggest that fires in this region result in high tree mortality (means of 83% and 76% at Arctic and subarctic sites, respectively). In both absolute and relative terms, aboveground carbon loss following fire is higher in Siberian larch forests than in North America, but belowground carbon loss is considerably lower. This suggests fundamental differences in wildfire behavior and carbon dynamics between dominant vegetation types across the boreal biome.

Lithogeochemical characteristics and potential hyperaccumulator identification as phytomining agent at the Ratatotok gold mine, Indonesia

In the future, phytomining will be an environmentally friendly alternative mining technology. Therefore, the exploration of vegetation types having the potential as hyperaccumulators in gold phytomining needs to be carried out. This study aimed to (1) investigate the effect of rock/soil mineralogy characteristics and Au content on the diversity of vegetation types at gold mine sites, and (2) determine the type of potential hyperaccumulator vegetation as a phytomining agent based on the Biological Concentration Factor (BCF). This study was conducted at the Ratatotok gold mine in North Sulawesi Province, Indonesia. The sampling locations consisted of 3 sites, i.e., Bulex, Yance, and Leon, and each site consisted of 5 sampling plots. Soil samples were taken from each sampling plot and then tested for gold content using the ICP-MS method and mineral content using the XRD method. Mineralized bedrock samples were also taken for mineralogical analysis through petrography. Data analysis of soil geochemistry was carried out descriptively. Quantitative descriptive analysis was also carried out to determine the dominant type of vegetation, which was potential for hyperaccumulators at the mine site. The results showed that gold content in the soil affected the diversity of vegetation, which was possibly due to gold stress, which affected plant growth. Based on the BCF value, three local plant species having potential as gold hyperaccumulators with moderate bioaccumulation ability (BCF&gt;0.1-1) were found, namely Pteris vittata, Syzygium aromaticum, and Swietenia mahagoni. However, the use of these plants as phytomining agents requires further research.

Assessing the occurrence of soil improvement and its relationship to the dominant life form in the high mountains of Central Spain

Soil in mountainous regions is vital to the health and preservation of these unique and diverse ecosystems. In dry and semi-arid regions, vegetation patches play a crucial role in soil nutrient heterogeneity through continuous feedback with soils, acting as barriers to collect runoff water, sediments, and nutrients from bare soil regions. Soil amelioration, an enhancement of soil biogeochemical processes, results in the formation of “fertility islands,” the extent of which is contingent on the plant species in question, as well as nutrient dynamics and water availability. Here, we collected soil from across a two-peak altitudinal gradient in the Sierra de Guadarrama high-mountains, each peak featuring a different dominant vegetation type (herbs vs. cushion-like) to compare soil nutrients and properties between bare soil and vegetation-covered patches (microhabitats). Soil improvement was assessed in the microhabitats using the Relative Interaction Index (RII). Fertility islands were shown to be prevalent in high-mountain ecosystems, as soil quality and properties were higher beneath vegetation-covered regions than bare soils. There was a difference in RIIs between the transects, with greater soil improvement in the cushion-dominated transect than the herb-dominated one. Changes in nutrient levels were unrelated to patch successional stage, indicaing that plant generations may not shape the spatial variability of soil attributes. Instead, species variety or the presence of dominant clonal species increased soil nutrients and aggregate stability, highlighting the importance of root shape and high biomass in nutrient retention and soil reinforcement. Finally, our findings imply that the poor, shallow soils in the examined peaks, in comparison to other mountains, may account for the poor facilitative interactions. Competition for the scarce resources at these peaks may intensify as climate warms. Thus, while these plants may grow with minimum assistance under current climate circumstances, their associations may be especially vulnerable to climate change.

Space use by African savannah elephants in an arid protected area dominated by a mosaic of different vegetation

AbstractThe African savannah elephant (Loxodonta Africana) migrate in response to limiting environmental factors in arid areas. Using global positioning systems (GPS) telemetry data, we determined: (i) the dominant vegetation types used by African savannah elephants and (ii) the differences in the area occupied by dominant vegetation types in Gonarezhou National Park (GNP) in Zimbabwe. Significant spatiotemporal differences (p &lt; 0.05) detected in vegetation types utilised by the African savannah elephant, and in the area covered by vegetation types induced a determinate foraging pattern. Global positioning system telemetry is a smart conservation tool for surveillance of movement patterns of African savannah elephants in protected areas.

Temperature and moisture sensitivities of soil respiration vary along elevation gradients: An analysis from long-term field observations

Based on long-term field observation data over 11 years at 23 sites in two mountainous areas (TS1 and TS2) at elevations from 829 to 2700 m, where the dominant vegetation type of TS1 and TS2 was temperate mixed broadleaf-coniferous forest and cold temperate coniferous forest, respectively, we analyzed the correlations between soil respiration (Rs) and abiotic and biotic factors to explore the response patterns of Rs to environmental factors within and between the sites along the elevation gradient. We found that soil moisture (θ) and its combinations (Ts × θ and θ/Ts) with soil temperature (Ts) increased significantly with increasing elevation, while Ts, soil bulk density (SBD), C/N ratio, and pH decreased significantly with increasing elevation. Within each site, both exponential- Ts (ET) and Gaussian-Ts (GT) models could be used for predicting the Rs seasonal variation, except for two sites in the area of TS1, where θ was a better predictor than Ts. The integrated ET–θ and GT–θ models could be applied to all sites except for 22S, and both were superior to the ET and GT models. The mean Rs of each site over the measurement period ranged from 3.07 to 6.94 μmol CO2 m−2 s−1 and showed a quadratic increase along the elevation gradient. Among the 23 sites, Q10 ranged from 1.15 to 3.79, and it increased with elevation, reaching a maximum at an elevation of 2366 m; the θ sensitivity parameter (d) decreased significantly with elevation and reached a minimum at an elevation of 1975 m. Both the d and Ts sensitivity parameter (b) of Rs were complementary to each other along the elevation gradient. Among the sites, Ts, θ, and combinations of the two were more important drivers for both Rs and Q10 variations than microbial and physicochemical indicators.

Analysis of effects of vegetation cover and elevation on water yield in an alpine basin of the Qilian Mountains in Northwest China by integrating the WRF-Hydro and Budyko framework

Alpine basins provide the main water resources and sustain socioeconomic development in arid regions. Understating how vegetation and elevation affect the water yield is crucial for sustainable water management of arid regions. However, the scarce observations, heterogeneous hydroclimatic conditions, and oversimplifications of the energy and biogeophysical processes in traditional hydrological models limit the comprehension of hydrological processes associated with water yield over alpine basins. This study combines the fully distributed WRF-Hydro model with the Budyko framework to characterize the water yield of an alpine basin named Xiying River Basin (XRB) located in Northwest China. Results show that WRF-Hydro driven by the remote-sensing-based products was able to reproduce both observed streamflow and evapotranspiration (ET) in the XRB. The ratio of transpiration to ET was considerably underestimated when only calibrating streamflow. Such underestimation can be solved by calibrating parameters related to soil surface resistance and leaf conductance. Additionally, for the dominant vegetation types (i.e., closed shrublands and grasslands) in the XRB, we found that closed shrublands have a lower water yield capacity than grasslands. Closed shrublands have a stronger ET rate, resulting in stronger soil moisture consumption, lower antecedent soil moisture, and higher soil water deficit, causing higher infiltration loss during rainfall events and lower water yield. Moreover, the water yield capacity increases with the increasing elevation, because the precipitation increases while the ET decreases as the elevation rises, and the topographical slope increases, resulting in lower infiltration, lower baseflow index, and higher water yield capacity. Our results also indicate that afforestation should not be encouraged for grasslands and closed shrublands in areas lower than 2800 m and 3200 m, respectively. Overall, this study provides scientific support for vegetation afforestation planning in the alpine regions.

Vegetation Analysis of the Area Surrounding a Wild Nest of Stingless Bees Tetragonula laeviceps (Smith, 1857) in Sumedang Regency, West Java

Indonesia is a mega biodiversity country that has a very abundant diversity of plants. Plant diversity is inseparable from the role of insects that help to pollinate them. One such insect is the stingless bee Tetragonula laeviceps, a bee that has a relatively small-to-medium body size and does not have a sting. Sumedang Regency is one of the regencies in the province of West Java; most of the Sumedang area consists of mountains and has protected forest areas with high biodiversity. The purpose of this study is to determine the biodiversity index of the vegetation around the Tetragonula laeviceps wild nests. Data collection is carried out using the method of inventory and systematic checkered lines, with a total plot of 320. The results of the study show that the vegetation is composed of 229 plant species from 75 families. The most dominant vegetation type with the highest value of KR, FR, DR, and INP in all plant categories is the Aren tree species (Arenga pinnata). The Shannon–Wiener diversity index in this tree category is 3186, the pole category is 3107, the sapling category is 3418, the seedling category is 3657, and the understory plants category is 3409, with all of the plant categories included in the high-diversity category.

Influence of human impacts on modern pollen assemblages and an assessment of their reliability in reconstructing climate in eastern China

Understanding the relationship between modern pollen, vegetation, and climate is essential for the reconstruction of paleoenvironments and human land use from fossil pollen spectra. In this study, we collected modern pollen data from natural vegetation and human-disturbed vegetation in eastern China. Results reveal that modern pollen assemblages reflect their natural or human-disturbed vegetation, and differ between northern and southern sample sites in eastern China. Natural vegetation communities are dominated by arboreal taxa, mainly Pinus, Castanopsis, Quercus, and Betula. Farmland, which is the dominant type of human-disturbed vegetation, is dominated by herbaceous taxa particularly Cerealia Poaceae (>35 μm), Poaceae, Chenopodiaceae, and Brassicaceae. In eastern China, pollen assemblages of north China are mainly Betula, Artemisia, Chenopodiaceae, Cerealia Poaceae, Brassicaceae, and Ranunculaceae, while pollen assemblages of south China are mainly Castanopsis, Quercus, Poaceae, Cyperaceae, and Euphorbiaceae. Poaceae, Cerealia Poaceae, Brassicaceae, and Chenopodiaceae from human-disturbed vegetation is mainly distributed at low elevations and has a smaller elevational range than natural vegetation. Pollen assemblages from natural vegetation perform better at reconstructing climate than pollen assemblages from human-disturbed vegetation in eastern China. Mean annual precipitation (Pann) is a better predictor than mean temperature of the coldest month (Mtco) and mean temperature of the warmest month (Mtwa). In this study, surface pollen assemblages from human-disturbed vegetation still reflect the characteristics of the local vegetation and can still be used to reconstruct climate. Nonetheless, for more accurate results, pollen assemblages from natural vegetation communities should preferentially be used in reconstructions.

Investigation of biogenic volatile organic compounds emissions in the Qinghai-Tibetan Plateau

Biogenic volatile organic compounds (BVOCs), which are produced and emitted by plants, have significant chemical reactivity in the atmosphere and impacting climate change. Qinghai Province, a vital component of the plateau, has abundant vegetation resources, primarily grasslands and forests, yet BVOCs emissions and their impact on air quality remain understudied. In this study, the emissions rates and compositions of BVOCs from seven dominant vegetation types in Qinghai Province were sampled and analyzed using a closed-loop stripping dynamic headspace sampling approach combined with GC–MS, and the total emissions of BVOCs in Qinghai province in 2021 were estimated by using G95 model. At the same time, the emission characteristics of various vegetation types were also analyzed. The results showed that the emissions rates and compositions of BVOCs differed significantly among vegetation types, with monoterpenes being the dominant emission composition in coniferous forests, which accounted for >70 % of the total BVOCs emissions, while isoprene being the main composition in alpine meadow, accounting for 84.96 %. The emissions of three typical vegetation types, Picea asperata, alpine meadow and alpine steppe, were monitored daily, revealing significant diurnal and clear unimodal patterns. The study also found that the annual average BVOCs emissions from vegetation sources in Qinghai Province were estimated to be 1550.63 Gg yr−1, with isoprene contributing the highest proportion of emissions, accounting for 56.94 %. Grassland was the largest BVOCs emission source in Qinghai Province, with an annual average emission of 1438.52 Gg yr−1. Additionally, BVOCs emissions in Qinghai Province showed strong seasonal and daily variation patterns, with the highest emissions occurring in summer, with the peak in July. These findings provide the characteristics of BVOCs emissions from vegetation sources in the Tibetan Plateau, which will contribute to a better understanding of their impact on atmospheric chemistry and climate change.