Search Results (50)

Atmospheric nitrogen (N) deposition and climate warming significantly influence soil nitrogen transformation processes. Nitrification, a key step in the N cycle, is primarily driven by ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). However, their responses to environmental changes in warm-temperate shrub tussock grasslands—a major grassland type in China—remain poorly understood. In this study, we examined the effects of N addition and warming on the community composition of ammonia oxidizers and soil nitrification potential (NP) through pot experiments simulating field conditions. Our results demonstrated that (1) the AOB community was more responsive to N addition and warming than AOA, with the genus Nitrosospira increasing by 6.30–21.75% under treatments; (2) soil pH increased significantly under warming (from 6.53 to 6.86) but remained unchanged under N addition; (3) NP increased significantly under all treatment conditions, most markedly under warming alone (2.83-fold increase compared to the control); and (4) NP was positively correlated with both soil pH and the relative abundance of Nitrosospira. These findings suggest that warming and N deposition enhance nitrification in shrub tussock soil by altering AOB community structure and increasing soil pH. This study provides new insights into the microbial mechanisms driving N cycling in warm-temperate grasslands under global change. Full article

Arctic warming is expected to alter permafrost landscapes and shift tundra ecosystems from greenhouse gas sinks to sources. We quantified plant biomass and necromass, carbon stocks, and microbial activity across five Low-Arctic tundra sites in the Yana–Indigirka Lowland (Chokurdakh, NE Siberia) during the 2024 growing season. Above- and below-ground plant biomass was measured by harvest adjacent to 50 × 50 m permanent plots; total C and N were determined by dry combustion on an elemental analyzer. Total organic carbon (TOC) stocks were calculated by horizon from TOC (%), bulk density, and thickness. Microbial basal respiration (BR), substrate-induced respiration (SIR), microbial biomass C (MBC), and the metabolic quotient (qCO₂) were assessed in litter/organic (O), peat (T), and mineral gley horizons. Mean above-ground biomass was 15.8 ± 1.5 t ha⁻¹; total living biomass averaged 43.1 ± 1.6 t ha⁻¹. Below-ground biomass exceeded above-ground by 1.73×. Carbon in above-ground, below-ground, and necromass pools averaged 7.8, 12.2, and 12.5 t C ha⁻¹, respectively. Surface organic horizons dominated ecosystem C storage: litter–peat stocks ranged from 234 to 449 t C ha⁻¹, whereas 0–30 cm mineral layers held 18–50 t C ha⁻¹; total (surface + 0–30 cm) stocks spanned 258–511 t C ha⁻¹ among sites. Key contributors to biomass and C storage were deciduous shrubs (Salix pulchra, Betula nana), bryophytes (notably Aulacomnium palustre), and the graminoids (Eriophorum vaginatum). BR and MBC were highest in O and T horizons (BR up to 21.9 μg C g⁻¹ h⁻¹; MBC up to 70,628 μg C g⁻¹) and declined sharply in mineral soil; qCO₂ decreased from O to mineral horizons, indicating more efficient C use at depth. These in situ data show that Low-Arctic tundra C stocks are concentrated in surface organic layers while microbial communities remain responsive to warming, implying high sensitivity of carbon turnover to thaw and hydrologic change. The dataset supports model parameterization and remote sensing of shrub–tussock tundra carbon dynamics. Full article

This study examines the growth dynamics of Nassella tenuis (Phil.) Barkworth, a palatable perennial tussock grass, abundant in the natural grasslands of Central Argentina. It focuses on the effects of water regimes and grazing history. Plants were collected from sub-humid and semiarid grasslands with contrasting grazing histories (grazed and ungrazed) and cultivated under controlled conditions. Key growth traits, such as leaf elongation, senescence, and net growth rates, as well as tiller production, were assessed across the growth cycle. The results reveal that sub-humid grasslands favor faster growth rates and higher tiller production, while semiarid grasslands exhibit lower growth rates, potentially reflecting adaptive strategies for water-limited environments. Seasonal analysis revealed distinct life cycle patterns: plants from sub-humid grasslands exhibited higher elongation rates during autumn and spring, whereas growth in semiarid plants remained consistently low across seasons. Grazing history significantly influenced growth patterns, with grazed plants showing reduced tiller numbers and growth rates but lower senescence rates, particularly in semiarid grasslands. These findings underscore the importance of aligning grazing management practices with the growth dynamics of N. tenuis and the water regime of the site to optimize forage production while maintaining grassland resilience. Full article

Our study was conducted in the Valle Nuevo National Park and included four habitat classes: tussock grass (Sabapa), pine forest (Pinoc), broadleaf forest (Boslat), and agricultural ecosystem (Ecoag). We had two main objectives: to comparatively describe millipede communities and to determine the relationships between population density/diversity and soil physicochemical variables. The research was cross-sectional and non-manipulative, with a descriptive and correlational scope; sampling followed a stratified systematic design, with eight transects and 32 quadrats of 1 m², covering 21.7 km. We found a sandy loam soil with an extremely acidic pH. The highest population density of millipedes was recorded in Sabapa, and the lowest in Ecoag. The highest alpha diversity was shared between Boslat (Margalef = 1.72) and Pinoc (Shannon = 2.53); Sabapa and Boslat showed the highest Jaccard similarity (0.56). The null hypothesis test using the weighted Shannon index revealed a statistically significant difference in diversity between the Boslat–Sabapa and Pinoc–Sabapa pairs. Two of the species recorded highly significant indicator values (IndVal) for two habitat classes. We found significant correlations (p < 0.05) between various soil physicochemical variables and millipede density and diversity. Full article

Insects’ body coloration may be indirectly influenced by their host plants. Perina nuda (Lepidoptera: Lymantriidae), commonly known as the Banyan Tussock Moth and a serious pest of banyan trees (Ficus spp.) in southern China, exhibits light body coloration during its first- to third-instar stages, with its coloration progressively darkening as it matures, but little is known of the relationship between larval body coloration and host plants. To address this gap, we examined the R (red), G (green), B (blue), and L (lightness) values of the head, dorsal thorax and abdomen, stripe, dorsal mid-line, and tail of larvae fed on different hosts and host endogenous substance by using quantitative image analysis and chemical determination. Our results revealed that larval body coloration exhibited conserved ontogenetic patterns but varied significantly with host species, developmental age, and anatomical region. Redundancy analysis identified chlorophyll-b as the dominant driver, strongly associating with dorsal thorax–abdomen pigmentation. Flavonoids exhibited subthreshold significance, correlating with darker dorsal mid-line coloration, while nutrients (sugars, proteins) showed negligible effects. Linear regression revealed weak but significant links between leaf and larval body coloration in specific body regions. These findings demonstrate that host plant endogenous substances play a critical role in shaping larval body coloration. This study provides a foundation for understanding the ecological and biochemical mechanisms underlying insect pigmentation, with implications for adaptive evolution and pest management strategies. Full article

The tea tussock moth, Euproctis pseudoconspersa (Strand), is a serious pest, and its sex pheromone is (R)-10,14-dimethylpentadecyl isobutyrate. A new and concise asymmetric synthesis of the sex pheromone and its enantiomer was accomplished. The chiral methyl of the pheromone was introduced by Evans’s template, while the extension of the carbon chain was achieved through Li₂CuCl₄-catalyzed coupling of chiral tosylate with Grignard reagent. Full article

Changes in land use and agricultural practices have altered the resilience of plant communities and can lead to the emergence of invasive species. One of these is the perennial grass species Bothriochloa ischaemum (L.) Kleng., whose diversity-reducing effects are known from several studies. Our exploratory questions were as follows: How does the presence of B. ischaemum affect the diversity and ratio of the species of sandy grasslands? To what extent does this diversity change depend on site characteristics? The supporting studies were carried out in five low-lying sand dune slacks and six relatively higher areas in the upper-intermediate part of the dunes and on an abandoned old field located in the Hungarian Great Plain in the Carpathian Basin. The cover of vascular plant species was recorded in all sampling sites in twelve 2 by 2 m plots, and the dataset was analysed using agglomerative cluster analyses and a non-parametric Kruskal–Wallis test. Five significantly different groups were identified, separating the vegetation types of the sides of the sand dunes, the vegetation types of the dune slack and the old field, and a Stipa borysthenica Kolkov ex Prokudin-dominated vegetation type. Our results suggest that B. ischaemum is only present as small tussocks on the drier, more exposed sides of dunes, with 3.9–24.2% average coverage; is less able to outcompete Festuca vaginata Waldst. et Kit. ex Willd. and S. borysthenica; and is only able to form large tussocks mainly in the lower dune slacks, with 45.6–79.5% average coverage. Here, in the wetter areas, it achieves high cover with a considerable accumulation of litter, and it becomes a dominant species in this association. The diversity-reducing effect of B. ischaemum on old-field grasslands depends on the age of the site and on the stability of the vegetation. Full article

The tea tussock moth (Euproctis pseudoconspersa) is a common tea plantation pest with Type III sex pheromone components (SPCs). However, the olfactory genes involved in the perception of Type III SPCs remain unknown. To identify the olfactory genes involved in E. pseudoconspersa olfactory perception, we sequenced the transcriptomes of different tissues from male and female moths. We identified 27 chemosensory proteins, 39 odorant-binding proteins (OBPs), 28 ionotropic receptors (IRs), and 67 odorant receptors (ORs). Phylogenetic and antennal abundance analyses showed that EpseOR12, EpseOR13, EpseOR15, EpseOR16, and EpseOR18 belonged to the pheromone receptor clades of Type II moths, with predominant expression in male antennae. Besides these EpseORs, EpseOR14 and EpseOR32 were two of the most abundant EpseORs in male antennae, where they were predominantly expressed. Four pheromone-binding proteins (PBPs) were identified, with higher expression in male antennae. EpseORs and EpsePBPs may be involved in Type III SPC detection. Additionally, a few EpseOBPs, EpseIRs, and EpseORs were predominantly expressed in either male or female antennae. These genes may play important roles in olfaction and may be involved in detecting host plant volatiles and pheromones. These results provide a foundation for further exploration of the molecular mechanisms of E. pseudoconspersa olfaction. Full article

Monitoring the location and severity of invasive plant infestations is critical to the management of their spread. Remote sensing can be an effective tool for mapping invasive plants due to its capture speed, continuous coverage, and low cost, compared to ground-based surveys. Serrated tussock (Nassella trichotoma) is a highly problematic invasive plant in Victoria, Australia, as it competes with the species in the communities that it invades. In this study, a workflow was developed and assessed for classifying the cover of serrated tussock in a mix of grazing pastures and grasslands. Using high-resolution RGB aerial imagery and vegetation field survey plots, random forest models were trained to classify the plots based on their fractional coverage of serrated tussock. Three random forest classifiers were trained by utilising spectral features (RGB bands and indices), texture features derived from the Grey-Level Co-occurrence Matrix, and a combination of all the features. The model trained on all the features achieved an $overallaccuracy$ of 67% and a $kappa$ score of 0.52 against a validation dataset. Plots with high and low infestation levels were classified more accurately than plots with moderate or no infestation. Notably, texture features proved more effective than spectral features for classification. The developed random forest model can be used for producing classified maps to depict the spatial distribution of serrated tussock infestation, thus supporting land managers in managing the infestation. Full article

Certain plant species have developed the ability to express biological nitrification inhibition (BNI), suppressing the activity of nitrifying microbes and thereby reducing the conversion of ammonium to nitrate. This study assessed the BNI capacity and the rhizosphere ammonia-oxidizing microbiome of two grass species: the endemic Australian Barley Mitchell grass (Astrebla pectinata) and the introduced koronivia grass (Urochloa humidicola), using soils from both agricultural land and native vegetation. In agricultural soil, koronivia grass exhibited significantly higher BNI capacity compared with Barley Mitchell grass. However, in native soil, this trend was reversed, with Barley Mitchell grass demonstrating a significantly greater BNI capacity than koronivia grass (52% vs. 38%). Koronivia grass significantly altered the composition of the ammonia-oxidizing bacteria community in its rhizosphere, leading to a decrease in the Shannon index and bacteria number. Conversely, Barley Mitchell grass reduced the Shannon index (1.2 vs. 1.7) and population size (3.28 × 10⁷ vs. 7.43 × 10⁷ gene copy number g⁻¹ dry soil) of the ammonia-oxidizing archaea community in its rhizosphere to a greater extent. These findings suggest that Australian Barley Mitchell grass may have evolved mechanisms to suppress soil archaeal nitrifiers, thereby enhancing its BNI capacity and adapting to Australia’s nutrient-poor soils. Full article

Gamba grass (Andropogon gayanus Kunth) is a tussock-forming forage species adapted to acid soils of Brazilian savannas and cultivated for grazing pastures. Four decades since its release, Planaltina prevails as the most commercialized cultivar of the species, even though the new cultivar BRS Sarandi could be a better alternative for Gamba-grass-based farms by presenting a greater leaf:stem ratio. The objective of this study was to evaluate the average daily live weight gain (ADG) of Nellore bulls (Bos indicus) for two Gamba grass cultivars—Planaltina and Sarandi. The experiment was conducted in Planaltina, Federal District, Brazil, for 3 years, namely 2018, 2018–2019, and 2020. The experimental design was a completely randomized block design with two treatments and three replicates, each one continuously stocked at three stocking rates (SR)—1.3, 2.6, and 4 young bulls/ha. Canopy height (CH), forage mass (FM), plant-part proportion (green leaf, stem, and dead material), and nutritive value were evaluated. In 2018, mean ADG for Sarandi pastures was greater (0.690 kg/bull/d) than that of Planaltina (0.490 kg/bull/d) (p < 0.10). In the subsequent year (2018–2019), there was no effect of cultivar (p > 0.10), while in 2020 the ADG was again affected by cultivar (p < 0.10), confirming the advantage of Sarandi (0.790 kg/bull/d) over Planaltina (0.650 kg/bull/d). In 2018 and 2020, the percentage of stems for Sarandi was about 3–6 pp less than for Planaltina (p < 0.10). As well as for stems, Sarandi pastures presented a shorter CH in 2028 and 2020 (6–7%) (p < 0.10). The positive high correlation of leaf:stem ratio with ADG (r = 0.70) probably predisposed the superiority of Sarandi over Planaltina. The distinguishing plant-part composition of Sarandi canopy promotes increasing weight gain of beef cattle when compared to cv. Planaltina. Full article

The fungal order Entomophthorales occurs worldwide, with most species infecting arthropods as pathogens. Species in this order can cause epizootics and change the behavior of infected hosts. Molecular data are available only for 20% of the known species, and distributions of species are seldom summarized. Significant diversity of hosts, poor molecular data availability, and poor resolution of the phylogenetic relationships within this fungal order suggest that the diversity of these fungi is not sufficiently described. The subfamily Erynioideae includes 111 arthropod pathogens, divided among six genera, with the genus Pandora being one of the most diverse genera. Sequences of 18S, 28S, and ITS for two species are used to place these Pandora species in a phylogenic tree of the subfamily; this tree also supports our synonymy of the genus Furia with Pandora. Among the two species specifically covered in this paper, Pandora gloeospora was observed during epizootics occurring in mushroom flies (Diptera: Sciaridae) on Agaricus bisporus cultures in Pennsylvania, Delaware, and Maryland (US) mushroom farms and also in Florida on Pleurotus sp. Outside the US, P. gloeospora was found infecting several Nematocera (Diptera) in Europe (France) and Asia (China). Pandora sylvestris n. sp. was collected during epizootics occurring in larvae of hickory tussock moths, Lophocampa caryae (Lepidoptera: Erebidae), in hardwood forests in Michigan and Vermont. Full article

The tea tussock moth is a pest that damages tea leaves, affecting the quality and yield of tea and causing huge economic losses. The efficient asymmetric total synthesis of the sex pheromone of the tea tussock moth was achieved using commercially available starting materials with a 25% overall yield in 11 steps. Moreover, the chiral moiety was introduced by Evans’ template and the key C-C bond construction was accomplished through Julia–Kocienski olefination coupling. The synthetic sex pheromone of the tea tussock moth will facilitate the subsequent assessment and implementation of pheromones as environmentally friendly tools for pest management. Full article

Comprehending the impacts of land-use type on soil nutrition and stoichiometry in watersheds is crucial for effective regional ecosystem management. However, a deeper understanding of the influence of land-use type on soil stoichiometry in karst agricultural watersheds is still lacking. Here, we analyzed the contents, stoichiometries, and drivers of topsoil C, N, and P in a karst agricultural watershed in China, focusing on six land-use types: paddy fields, dry farmland, tussock land, shrubland, shrubby tussock land, and woodland. We found that woodland exhibited significantly higher soil organic carbon (SOC) content than other land-use types except shrubland. Moreover, woodland exhibited the highest total nitrogen (TN) and total phosphorus (TP) contents compared with other land-use types. C/N and N/P ratios did not vary significantly with land-use type, whereas dry farmland (18.68) showed a significantly lower C/P ratio than woodland (39), shrubland (39.92), and paddy fields (34.87). In addition, our results revealed that soil pH, catalase and invertase activity, and bacterial and actinomycetes abundance significantly influenced C, N, and P content and stoichiometry. These findings reveal that interactions between multiple biotic and abiotic factors drive variability in soil stoichiometry, offering valuable insight for land improvement and ecological management in karst agricultural watersheds. Full article

Resin is a plastic-like product of trees. Older occurrences of such resin are referred to as amber and are considered fossil resin. Younger resins are termed copals. Even younger ones have been dubbed defaunation resins. Non-fossil resins remain in a terminological limbo, often referred to as “sub-fossils”. We report two lepidopteran caterpillars preserved in non-fossil resin: one from Madagascar, one from Brazil. Prominent hairs (=setae) and spines (=spine-like setae) of the specimens make it likely that they represent larvae of Erebidae (e.g., tussock moths and others). So far, most known caterpillars preserved in resins are either “naked” or bear protective cases; only few are armoured with spines or hairs. In particular, long-haired caterpillars such as the ones reported here are so far almost absent. Only one specimen with comparable setae has been reported from 15-million-year-old Dominican amber, but no significant details of this specimen are accessible. We briefly also review the record of caterpillars known from the Holocene, recognising that it is very sparse. The new specimens demonstrate that very hairy caterpillars can readily be preserved in resins in fine detail. Furthermore, the specimens increase the known size range of caterpillars preserved in resins, with one measuring more than 12 mm. Full article