Habitat loss weakens the positive relationship between grassland plant richness and above-ground biomass.

Habitat loss and fragmentation per se have been shown to be a major threat to global biodiversity and ecosystem function. However, little is known about how habitat loss and fragmentation per se alters the relationship between biodiversity and ecosystem function (BEF relationship) in the natural landscape context. Based on 130 landscapes identified by a stratified random sampling in the agro-pastoral ecotone of northern China, we investigated the effects of landscape context (habitat loss and fragmentation per se) on plant richness, above-ground biomass, and the relationship between them in grassland communities using a structural equation model. We found that habitat loss directly decreased plant richness and hence decreased above-ground biomass, while fragmentation per se directly increased plant richness and hence increased above-ground biomass. Fragmentation per se also directly decreased soil water content and hence decreased above-ground biomass. Meanwhile, habitat loss decreased the magnitude of the positive relationship between plant richness and above-ground biomass by reducing the percentage of grassland specialists in the community, while fragmentation per se had no significant modulating effect on this relationship. These results demonstrate that habitat loss and fragmentation per se have inconsistent effects on BEF, with the BEF relationship being modulated by landscape context. Our findings emphasise that habitat loss rather than fragmentation per se can weaken the positive BEF relationship by decreasing the degree of habitat specialisation of the community.

Compared with soil fungal diversity and microbial network complexity, soil bacterial diversity drives soil multifunctionality during the restoration process.

Understanding factors driving soil multifunctionality can help with terrestrial ecosystem restoration. Soil microbial diversity and network complexity are two important factors influencing ecosystem multifunctionality. However, their effects on soil multifunctionality are still unclear. Based on high-throughput sequencing, we analyzed soil microbial alpha diversity and network complexity and their relative impacts on soil multifunctionality during the aerial seeding restoration process from 1983 to 2017 in Mu Us sandy land, China, a region threatened by desertification. Our results showed soil bacterial and fungal alpha diversity and multifunctionality increased with aerial seeding restoration. We found the community composition of soil bacteria and fungi changed with restoration periods. The keystone species of the soil bacterial network changed during restoration, while those of the soil fungal network remained unchanged. Soil bacterial and fungal species mainly maintained positive associations throughout the restoration periods. Soil bacterial network complexity initially decreased before increasing with restoration, while soil fungal network complexity increased continuously. Soil multifunctionality was found to have significantly positive correlations with soil fungal network complexity and soil bacterial alpha diversity. Compared with soil fungal alpha diversity and soil microbial network complexity, soil bacterial alpha diversity significantly promoted soil multifunctionality. Our research highlights the critical impact that soil bacterial alpha diversity plays in soil multifunctionality in restored ecosystems threatened by desertification.

Promoting effects of soil C and N and limiting effect of soil P jointly determine the plant diversity during the aerial seeding restoration process in Mu Us sandy land, China.

Introduction: Exploring the change and maintaining mechanism of plant diversity is of great significance for guiding the restoration of degraded ecosystems. However, how plant taxonomic, functional, and phylogenetic diversity change during long-term ecosystem restoration process and their driving factors remain unclear. Methods: Based on the 35-year time gradient of aerial seeding restoration in Mu Us sandy land, this study explored the changes in plant taxonomic, functional, and phylogenetic diversity and the driving factors. Results: The results showed that plant taxonomic, functional, and phylogenetic diversity showed consistent response with the aerial seeding restoration, all of which increased first and then tended to a saturation state in the middle of restoration (14 years). TN, TOC, and NO3 --N increased with aerial seeding restoration and showed a significant positive correlation with plant diversity of the three dimensions, while AP showed a negative correlation. Soil nitrogen and carbon promoted the increase of diversity of three dimensions in the early restoration period, while phosphorus limited the increase of diversity of three dimensions in the middle and late restoration periods. The diversity of three dimensions was mainly affected by restoration time, soil nutrients, and climate factors, and the coupling effect of restoration time and soil nutrients was dominant. Discussion: These findings indicate that the plant diversity in different dimensions and soil nutrients are improved by aerial seeding restoration. Our study highlights that aerial seeding restoration mainly improves plant diversity by increasing soil nutrients, and the relative effects of different soil nutrients on plant diversity during restoration are inconsistent.

Biodiversity in Urban Green Space: A Bibliometric Review on the Current Research Field and Its Prospects.

Understanding the development process of urban green space and biodiversity conservation strategies in urban green space is vital for sustainable urban development. However, a systematic review of the urban green space biodiversity research is still lacking. We have retrieved 3806 articles in WOS core journals and carried out the bibliometrics analysis through the three related search terms: urban, green space, and biodiversity. We found that: (1) the year 2009 was a changing point, and the number of articles have increased exponentially since 2009. The United States, China, Europe, and Australia are closely linked, and four research centers have formed; (2) all studies can be classified into three research themes: "Pattern of Urban Green Biodiversity", "Ecological Function of Urban Green Biodiversity", and "Sustainability of Urban Green Biodiversity"; (3) based on the evolution of keywords, this field is divided into the budding stage (1998-2012) and the development stage (2012-2021). The keywords in the budding stage focus on the diversity of different species, and the keywords in the development stage focus on the ecosystem services, biodiversity protection, and residents' satisfaction; (4) the future research focus may be in three aspects: studies on green space in the less urbanized area and urban-rural ecotone, the regulation mechanism and cultural services of urban green space, and the rational layout and management of urban green space. This study hopes to provide a reference for future research on urban green space biodiversity and promote the sustainable development of urban green space.

Plant functional ß diversity is an important mediator of effects of aridity on soil multifunctionality.

Previous studies have demonstrated that plant diversity not only plays an important role in maintaining ecosystem functions but can also mediate the impact of climate change on ecosystem functions. However, the relative importance of multiple aspects of diversity at different scales remains unclear. In this study, we investigated species, functional, and phylogenetic aspects of diversity at α and ß scales, and measured eight soil functions (aboveground productivity, soil organic carbon, total soil nitrogen, total soil phosphorus, soil available nitrogen, soil available phosphorus, soil carbon-nitrogen ratio, and soil nitrogen-phosphorus ratio) to comprehensively assess the relationship between multiple aspects and scales of plant diversity and soil multifunctionality along an aridity gradient across the grasslands of Inner Mongolia. Diversity at α and ß scales explained soil multifunctionality synergistically. Functional diversity explained most of the soil multifunctionality, while phylogenetic diversity explained the least. Aridity had both direct effects on soil multifunctionality, and indirect effects mediated mainly by functional α and ß diversity. These findings indicate that in addition to α diversity, ß diversity also played an important role in maintaining soil multifunctionality, and was an important mediator for the adverse impact of aridity on soil multifunctionality. Our study highlights the critical role of ß diversity, especially regarding functional traits, in predicting the consequences of the increasingly arid conditions in the Inner Mongolian grasslands.

Adaptation of Dominant Species to Drought in the Inner Mongolia Grassland - Species Level and Functional Type Level Analysis.

The adaptation of plants to drought through the adjustment of their leaf functional traits is a hot topic in plant ecology. However, while there is a good understanding of how individual species adapt to drought in this way, the way in which different functional types adapt to drought along a precipitation gradient remains poorly understood. In this study, we sampled 22 sites along a precipitation gradient in the Inner Mongolia grassland and measured eight leaf functional traits across 39 dominant species to determine the adaptive strategies of plant leaves to drought at the species and plant functional type levels. We found that leaf functional traits were mainly influenced by both aridity and phylogeny at the species level. There were four types of leaf adaptations to drought at the functional type level: adjusting the carbon-nitrogen ratio, the specific leaf area, the nitrogen content, and the specific leaf area and leaf nitrogen content simultaneously. These findings indicate that there is the trade-offs relationship between water and nitrogen acquisition as the level of drought increases, which is consistent with the worldwide leaf economics spectrum. In this study, we highlighted that the leaf economic spectrum can be adopted to reveal the adaptations of plants to drought in the Inner Mongolia grassland.