Effects of short- and long-term plant functional group loss on alpine meadow community structure and soil nutrients.

The rapid loss of global biodiversity can greatly affect the normal functioning of ecosystems. However, how biodiversity losses affect plant community structure and soil nutrients is unclear. We conducted a field experiment to examine the short- and long-term effects of removing plant functional groups (Gramineae, Cyperaceae, legumes, and forbs) on the interrelationships among the species diversity, productivity, community structure, and soil nutrients in an alpine meadow ecosystem at Menyuan County, Qinghai Province. The variations in the species richness, above- and belowground biomass of the community gradually decreased over time. Species richness and productivity were positively correlated, and this correlation tended to be increasingly significant over time. Removal of the Cyperaceae, legumes, and other forbs resulted in fewer Gramineae species in the community. Soil total nitrogen, phosphorus, organic matter, and moisture contents increased significantly in the legume removal treatment. The removal of other forbs led to the lowest negative cohesion values, suggesting that this community may have difficulty recovering its previous equilibrium state within a short time. The effects of species removal on the ecosystem were likely influenced by the species structure and composition within the community. Changes in the number of Gramineae species indicated that they were more sensitive and less resistant to plant functional group removal. Legume removal may also indirectly cause distinct community responses through starvation and compensation effects. In summary, species loss at the community level led to extensive species niche shifts, which caused community resource redistribution and significant changes in community structure.

Climate and litter traits affect the response of litter decomposition to soil fauna.

OBJECTIVES: Soil fauna plays a crucial role in contributing to litter breakdown, accelerating the decomposition rate and enhancing the biogeochemical cycle in terrestrial ecosystems. Comprehending the specific fauna role of functional species in litter decomposition is challenging due to their vast numbers and diversity. Climate and litter quality are widely acknowledged as dominant drives of litter decomposition across large spatial scales. However, the pattern of climate and litter quality modulates the effect of soil fauna on litter decomposition remains largely unexplored. To address this gap, we conducted an extensive analysis using data from 81 studies to investigate how climate and litter traits affects soil fauna in the decomposition. DATA DESCRIPTION: The paper describes fauna body size, climate zones (tropical, subtropical and temperate), ecosystem types (forest, grassland, wetland and farmland), soil types (sand, loam and clay), decomposed duration (< 180, 180-360, > 360 days), litter initial traits, average annual temperature and precipitation. The litter traits encompass various parameters such as concentrations of carbon, nitrogen, phosphorus, potassium, lignin, cellulose, total phenol, condensed tannin, hydrolysable tannin and other nutrient traits. These comprehensive datasets provide valuable insights into the role of soil fauna on the decomposition at global scale. Furthermore, the data will give researchers keys to assess how climate, litter quality and soil fauna interact to determine decomposition rates.

Lattice Strain Mediated Reversible Reconstruction in CoMoO4·0.69H2O for Intermittent Oxygen Evolution.

A heterogeneous interface usually plays a versatile role in modulating catalysis and the durability of hybrid electrocatalysts for oxygen evolution reaction (OER), and its intrinsic mechanism is still in dispute due to an uncertain correlation of initial, intermediate and active phases. In this article, the CoMoO4·0.69H2O/Co3O4 heterogeneous interface is configured to understand the evolution kinetics of these correlated phases. Due to the chemically and electrochemically "inert" character of Co3O4 support, lattice strain with 3.31% tuning magnitude in primary CoMoO4·0.69H2O can be inherited after spontaneous dissolution of molybdenum cations in electrolyte, dominating catalytic activity of the reconstructed CoOOH. In situ Raman spectroscopy demonstrates reversible conversion between active CoOOH and amorphous cobalt oxide during OER when positive and negative potentials are sequentially supplied onto hybrid catalysts with favorable strain. Therefore, superior durability with negligible decay after 10 cycles is experimentally identified for intermittent oxygen evolution. Theoretical calculations indicate that appropriate stress within the electrocatalyst could reduce the reaction energy barrier and enhance the OER performance by optimizing the adsorption of intermediates.

Effects of Pedicularis kansuensis Expansion on Plant Community Characteristics and Soil Nutrients in an Alpine Grassland.

Pedicularis kansuensis is an indicator species of grassland degradation. Its population expansion dramatically impacts the production and service function of the grassland ecosystem, but the effects and mechanisms of the expansion are still unclear. In order to understand the ecological effects of P. kansuensis, three P. kansuensis patches of different densities were selected in an alpine grassland, and species diversity indexes, biomasses, soil physicochemical properties, and the mechanism among them were analyzed. The results showed that P. kansuensis expansion increased the richness index, the Shannon−Wiener index significantly, and the aboveground biomass ratio (ABR) of the Weed group (p < 0.05), but reduced the total biomass of the community and the ABR of the Gramineae and Cyperaceae decreased insignificantly (p > 0.05); soil moisture, soil AOC, and NO3−·N decreased significantly (p < 0.05), while soil pH and total soil nutrients did not change significantly, and available phosphorus (AP) decreased at first and then increased (p < 0.05). The structural equation model (SEM) showed that P. kansuensis expansion had a significant positive effect on the community richness index, and a significant negative effect followed on the soil AOC from the increase of the index; the increase of pH had a significant negative effect on the soil AOC, NO3−·N, and AP. It indicated that P. kansuensis expansion resulted in the increase of species richness, the ABR of the Weed group, and the community's water demand, which promoted the over-utilization of soil available nutrients in turn, and finally caused the decline of soil quality. This study elucidated a possible mechanism of poisonous weeds expansion, and provided a scientific and theoretical basis for grassland management.

Plant-defense mimicry facilitates rapid dispersal of short-lived seeds by hornets.

Rates of seed dispersal have rarely been considered important. Here, we demonstrate through field observations and experiments that rapid dispersal is essential for the unusually short-lived seeds of Aquilaria sinensis (agarwood; Thymelaeaceae), which desiccate and die within hours of exposure by fruit dehiscence in the hot, dry forest canopy in tropical southwest China. We show that three species of Vespa hornets remove most seeds within minutes of exposure. The hornets consume only the fleshy elaiosomes and deposit most seeds in damp shade, where they can germinate, a mean of 166 m from the parent tree. Electrophysiological assays and field experiments demonstrate that the hornets are attracted by highly volatile short-carbon-chain (C5-C9) compounds, including aldehydes, ketones, alcohols, and acids, emitted from the dehiscent fruit capsule. These attractive fruit volatiles share 14 of 17 major electrophysiologically active compounds with those emitted from herbivore-damaged leaves, which attract predators, including hornets. Rapid seed dispersal thus appears to have been achieved in this species by the re-purposing of a rapid indirect defense mechanism. We predict that rapid seed dispersal by various mechanisms will be more widespread than currently documented and suggest that volatile attractants are more effective in facilitating this than visual signals, which are blocked by vegetation.

The evolution of increased competitive ability, innate competitive advantages, and novel biochemical weapons act in concert for a tropical invader.

There are many non-mutually exclusive mechanisms for exotic invasions but few studies have concurrently tested more than one hypothesis for the same species. Here, we tested the evolution of increased competitive ability (EICA) hypothesis in two common garden experiments in which Chromolaena odorata plants originating from native and nonnative ranges were grown in competition with natives from each range, and the novel weapons hypothesis in laboratory experiments with leachates from C. odorata. Compared with conspecifics originating from the native range, C. odorata plants from the nonnative range were stronger competitors at high nutrient concentrations in the nonnative range in China and experienced far more herbivore damage in the native range in Mexico. In both China and Mexico, C. odorata was more suppressed by species native to Mexico than by species native to China. Species native to China were much more inhibited by leaf extracts from C. odorata than species from Mexico, and this difference in allelopathic effects may provide a possible explanation for the biogeographic differences in competitive ability. Our results indicate that EICA, innate competitive advantages, and novel biochemical weapons may act in concert to promote invasion by C. odorata, and emphasize the importance of exploring multiple, non-mutually exclusive mechanisms for invasions.