Species coculture can increase agro-biodiversity and therefore constitutes an ecological intensification measure for agriculture. Rice-aquatic animal coculture, one type of species coculture, has been practiced and researched widely. Here, we review recent studies and present results of a quantitative analysis of literature on rice-aquatic animal coculture systems. We address three questions: (i) can rice yield and soil fertility be maintained or increased with less chemical input through rice-aquatic animal coculture? (ii) how do aquatic animals benefit the paddy ecosystem? (iii) how can coculture be implemented for ecological intensification? Meta-analysis based on published papers showed that rice-aquatic animal cocultures increased rice yield, soil organic carbon and total nitrogen and decreased insect pests and weeds compared with rice monocultures. Studies also showed that rice-aquatic animal cocultures reduced pesticide and fertilizer application compared with rice monocultures. Rice plants provide a beneficial environment for aquatic animals, leading to high animal activities in the field. Aquatic animals, in turn, help remove rice pests and act as ecological engineers that affect soil conditions, which favor the growth of rice plants. Aquatic animals promote nutrient cycling and the complementary use of nutrients between rice and aquatic animals, which enhances nutrient-use efficiency in the coculture. To generate beneficial outcomes, how to develop compatible partnerships between rice and aquatic animals, and compatible culturing strategies for coculture systems are the key points. Investigating which traits of aquatic animals and rice varieties could best match to create productive and sustainable coculture systems could be one of the future focuses.

Ecological intensification (EI) is the enhancement of ecosystem services to complement or substitute for the role of anthropogenic inputs in maintaining or increasing yields. EI has potential to increase farming’s environmental sustainability, e.g. reducing environmentally harmful management activities while sustaining yields. EI is based upon ecological processes which in turn are influenced by biodiversity. We review how biodiversity, particularly vascular plant diversity, can regulate ecosystem processes relevant to EI at multiple spatial scales. At an individual plant genotype level, complementarity in functional traits has a direct impact on productivity. At in-field, population level, mixtures of crop types confer resilience to minimize the risk of pest and disease incidence and spread. Scaling up to the field level, a diversity of non-crop plants (i.e. weeds) provides resources necessary for in-field functional processes, both below ground (carbon inputs, decomposition) and above ground (resource continuity for pollinators and natural enemies). At the landscape scale, mosaics of semi-natural and managed vegetation provide buffers against extreme events through flood and drought risk mitigation, climate amelioration and pest population regulation. Overall this emphasizes the importance of heterogeneity across scales in maintaining ecosystem functions in farmland. Major research challenges highlighted by our review include the need: to better integrate plant functional diversity (from traits to habitat scales) into cropping system design; to quantify the (likely interactive) contribution of plant diversity for effective EI relative to other management options; and to optimize through targeted management the system function benefits of biodiversity for resilient, efficient and productive agroecosystems.

Inspired by grassland biodiversity experiments studying the impact of plant diversity on primary productivity, the Crop Diversity Experiment setup in 2018 aimed at testing whether these biodiversity benefits also hold for annual crop systems and whether crop mixtures also achieved transgressive overyielding, i.e. yield in mixture that was higher than the most productive monoculture. The first 3 years of the experiment demonstrated that crop mixtures do not only increase yield compared with an average monoculture but often also compared with the highest yielding monoculture. The crop diversity effects were stronger under more stressful environmental conditions and were often achieved in mixtures with legume crops. However, we observed transgressive overyielding also under favorable conditions and in mixtures without legumes. With our investigation of the underlying mechanisms of the yield benefits we found both direct complementarities between crop species and indirect effects via other organisms. The former included chemical, spatial and temporal complementarity in Nuptake, complementary root distribution leading to complementary water uptake, as well as spatial and temporal complementarity in light use. Among the indirect mechanisms we identified complementary suppression of weeds and more abundant plant growth-promoting microbes in crop mixtures, apart from complementarity in pest and disease suppression not yet studied in the Crop Diversity Experiment but demonstrated elsewhere. In consequence, the Crop Diversity Experiment supports not only the assumption that the ecological processes identified in biodiversity experiments also hold in crop systems, but that diversification of arable crop systems provides a valuable tool to sustainably produce food.

Crop variety mixtures can provide many benefits, including pathogen suppression and increased yield and yield stability. However, these benefits do not necessarily occur in all mixtures, and the benefits of diversity may be compromised by disadvantages due to increased crop heterogeneity. In-field development of mixtures by assembling many combinations of crop genotypes without prior expectation about which genotypes need to be combined to produce well-performing mixtures results in prohibitively large designs. Therefore, effective tools are required to narrow down the number of promising variety mixtures, and to then identify in experiments which of these deliver the highest benefits. Here, we first review current knowledge about the mechanisms underlying effects in ecological diversity experiments and in current agricultural applications. We then discuss some of the principal difficulties arising in the application of this knowledge to develop good variety mixtures. We also discuss non-conventional approaches to solve some of these issues. In particular, we highlight the potential and limitations of trait-based methods to determine good variety mixing partners, and argue that nontraditional traits and trait-derived metrics may be needed for the trait-based approach to deliver its full potential. Specifically, we argue that good mixing partners can be identified using modern genetic and genomic approaches. Alternatively, good mixtures may be obtained by combining varieties that respond differently to environmental variation; such varieties could easily be identified in standard variety testing trials. Preliminary analyses show that niche differences underlying the different environmental responses can indicate functional complementarity and promote mixture yield and yield stability.

One central challenge for humanity is to mitigate and adapt to an ongoing climate and biodiversity crisis while providing resources to a growing human population. Ecological intensification (EI) aims to maximize crop productivity while minimizing impacts on the environment, especially by using biodiversity to improve ecosystem functions and services. Many EI measures are based on trophic interactions between organisms (e.g. pollination, biocontrol). Here, we investigate how research on multitrophic effects of biodiversity on ecosystem functioning could advance the application of EI measures in agriculture and forestry. We review previous studies and use qualitative analyses of the literature to test how important variables such as landuse parameters or habitat complexity affect multitrophic diversity, ecosystem functions and multitrophic biodiversity-ecosystem functioning relationships. We found that positive effects of biodiversity on ecosystem functions are prevalent in production systems, largely across ecosystem function dimensions, trophic levels, study methodologies and different ecosystem functions, however, with certain context dependencies. We also found strong impacts of land use and management on multitrophic biodiversity and ecosystem functions. We detected knowledge gaps in terms of data from underrepresented geographical areas, production systems, organism groups and functional diversity measurements. Additionally, we identified several aspects that require more attention in the future, such as trade-offs between multiple functions, temporal dynamics, effects of climate change, the spatial scale of the measures and their implementation. This information will be vital to ensure that agricultural and forest landscapes produce resources for humanity sustainably within the environmental limits of the planet.

Two formerly broadly distributed woody Atriplex species now occur as fragmented populations across a range of microhabitats in the San Joaquin Valley Desert, southern California. We hypothesized that A. lentiformis and A. polycarpa exhibit inter- and intra-specific differences in their leaf and stem structural and functional traits corresponding with differences in soil salinity and aridity. Water potential, xylem structure and function and leaf traits were compared between three populations of A. lentiformis and four populations of A. polycarpa. The two species significantly differed in their xylem traits, with A. lentiformis displaying lower xylem density, wider mean and maximum vessel diameters and higher hydraulic conductivity (Ks). They also differed in their leaf traits, such that A. lentiformis had larger leaves with higher specific leaf area (SLA) than A. polycarpa. Significant intra-specific differences occurred among leaf traits (leaf area, SLA) in A. lentiformis populations. In contrast, populations varied in their stem xylem structural traits (mean vessel wall thickness, mean vessel diameter, maximum vessel length) among A. polycarpa populations. Many of these differences were associated with soil salinity in A. lentiformis, and with minimum seasonal water potential in A. polycarpa. Overall, both saltbush species showed high intra- and inter-specific trait variation. This could be a critical consideration in understanding the evolution of these native species and has important implications for their conservation and restoration.

Although flower temperature plays an important role in plant reproduction, how it varies spatially on the flower surface is unclear, especially in alpine plants. To characterize spatial variation in flower surface temperature, we examined thermal images of flowers of 18 species along an altitudinal transect from 3200 to 4000 m on Lenglong Mountain on the north-eastern Qinghai-Tibetan Plateau. The surface temperature varied considerably within a flower or floral unit in all plants under sunlight, and was about 1 °C with a maximum of 11 °C higher in the center than at the edges. Solar radiation and flower shape significantly affected the temperature range and standard deviation and the ratio of flower center to edge temperature. The spatial variability of temperature increased with flower size. Flowers in the Asteraceae had higher surface temperatures, greater spatial variability of temperature, and consistently higher and more stable temperatures in the center than at the edge. The ratio of flower center to edge temperature increased with altitude in most species. Heat buildup at the flower center is likely to be widespread in alpine plants; further studies are needed to explore its ecological and evolutional roles.

Spatiotemporal variations in plant-pollinator interactions drive floral evolution and shape the diversity of flowers in angiosperms. However, the potential role of plant-pollinator interactions in driving floral differentiation across flowering times within a population has not been documented. In this study, we aimed to quantify the variations in pollinator-mediated selection of floral traits across different flowering times of Primula sikkimensis (an entomophilous plant) in two natural populations. The results demonstrated that plants were shorter and produced fewer flowers with larger sizes in the early flowering time than in the late flowering time. In early flowering time, pollinator types were fewer and visitation frequency was lower than in late flowering time, resulting in lower female fitness. Pollinator-mediated selection of floral traits varied with flowering time, and more floral traits received pollinator-mediated selection during early flowering time. These results highlight that temporal variation in plant-pollinator interactions may have a potential role in driving floral diversification within the population.

According to the original optimal reproductive allocation theory, plants should shift from vegetative growth to reproductive allocation abruptly and completely. Some plants do this, and it is also considered a good strategy for crop plants to maximize yield, but most plants shift gradually. Modified versions of the theory predict such a gradual transition from growth to reproduction. We hypothesize that kin selection can also alter the predictions of optimal allocation theory. We investigated the theoretical implications of both positive and negative kin selection on the timing of plant reproductive development using mathematical models. Under reasonable assumptions of costs and benefits, plants under kin selection are more likely to shift from growth to reproduction in an abrupt way when the initial value of the ratio between reproductive and vegetative biomass is high. Supported by empirical observations, our theoretical predictions have important implications in linking life history and energy allocation as well as for improving yields in agriculture.

Plant species often show different taxonomic and functional characteristics between limestone forests (LFs) and non-limestone forests (NLFs) in tropical regions. Pteridophyte species are one of the major components in tropical rainforests； however, the morphological and physiological characteristics of pteridophytes occurring in LFs are poorly understood. We evaluated the differences in seven leaf functional traits between pteridophyte species in LFs and NLFs in southwest China. We measured leaf water content, morphological traits including leaf size, leaf thickness, stomatal length and stomatal density (SD), and physiological traits including stomatal conductance and photosynthetic rate from a total of 25 species. We found that pteridophytes had thicker and smaller leaves with lower SD and stomatal conductance in LFs compared with NLFs, probably reflecting their adaptations in water use strategies. These differences, however, became non-significant when phylogenetic relationships were taken into account, suggesting that phylogenetic conservatism shapes trait differences and ultimately species composition in LFs and NLFs. Some species that were commonly found in both LFs and NLFs exhibited intraspecific variation between forest types, with lower SD in LFs. Our findings suggest that only a handful of pteridophyte species can adapt to their water use strategies in both LFs and NLFs, and thus adaptative radiation is unlikely to occur.

Differences in plant leaf elemental contents due to seasonal climate change reflect potential plant growth strategies. However, the distribution patterns of elements mediated by seasonal climate change remain unclear. This limits assessment of plant growth status and prediction of plant growth dynamics under global climate change. We collected 41 subtropical evergreen broadleaf plant leaves (31 tree species and 10 shrub species) during the wet and dry seasons, and determined foliar contents of macro- and microelements by inductively coupled plasma mass spectrometer. Our results showed that 41 plant leaves had significantly greater macroelement contents and significantly lower microelement contents in wet season than dry season. The highest macroelement content was in tree layer plants in wet season, followed by tree layer plants in dry season and shrub layer plants in wet season, the lowest was in shrub layer plants in dry season. The highest microelement content was in tree and shrub layer plants in dry season, followed by shrub layer plants in wet season, the lowest was in tree layer plants in wet season. Our results show that macro- and microelement contents of plant leaves with different vertical structures are affected by seasonal climate change. The transition from wet to dry season was detrimental to tree layer plants growth, but had less impact on shrub layer plants growth. These findings provide valuable evidence for predicting how different vertically structured subtropical evergreen broadleaf plants can adapt to changes in wet and dry season environments and to future global climate change.

High total P content but insufficient available P in soil is an obstacle that restricts the efficient utilization of P in saline-alkali soil regions. Although saline-alkali resistant P-solubilizing bacteria (PSB) solubilize insoluble P, few studies have focused on their application in plant growth. We isolated a PSB strain, identified as Bacillus sp. DYS211, from bird droppings in saline-alkali regions and determined its growth characteristics and resistance to salt and alkalis. To investigate the effect of PSB on the germination and growth of plant seeds, we performed a potting experiment using Suaeda salsa with PSB added. The PSB strain grew rapidly in the first 12 h, and the solubilized P content from PSB reached a maximum of 258.22 mg L^-1 at 48 h. Saline-alkali tolerance and P-solubilizing ability tests showed that Bacillus sp. DYS211 preferred to dissolve inorganic P, was halophilic, and had a good P-solubilizing effect at 1%-8% salinity (available P > 150 mg L^-1). It exhibited good P solubilization abilities when glucose and sucrose were used as C sources or when ammonium sulfate, ammonium nitrate or yeast extract powder were used as N sources. In the growth promotion test, PSB increased seed germination, particularly under high-salinity stress, with a growth promotion of 8.33%. The PSB also improved the growth of S. salsa, including plant height and biomass (up to three times) under both saline and alkaline conditions, and the stem diameter increased under high-salinity stress. This strain demonstrates potential for vegetation restoration in saline-alkali regions.

Litter inputs have great impacts on the soil properties and ecosystem functioning in forests. Rapid litter decomposition leads to decreases in planted forest agricultural waste and enhances the nutrient cycle in forests. The breakdown of litter and the release of various components depend heavily on enzymes. However, the effects of exogenous enzyme preparations on litter decomposition have been hardly investigated. In this study, we examined how these enzymes affected the remaining rate of litter quality, nutrient content (C, N, K), and microbial community diversity. Taking Eriobotrya japonica litter as the research object, five exogenous enzymes (laccase, lignin peroxidase, leucine arylamidase, cellulase, and acid phosphatase) were applied to litter leaves. The mass remaining rate and main nutrient content of the litter were measured during the decomposition period. The microbial diversity attached to the surface of the litter was determined after decomposition at constant temperature and humidity for 189 days. Application of laccase and lignin peroxidase increased litter degradation by affecting microbial diversity, N and K contents. Addition of leucine arylamidase leaded to an increase in N content, and decreased the quality of the litter. The cellulose and lignin decomposition rate in litters was unaffected by the addition of cellulase, laccase, and lignin peroxidase. These results indicate that exogenous addition of enzymes may alter the nutrient content and microbial community, thus affecting litter decomposition. It is imperative to investigate the effects and mechanisms of exogenous enzymes on litter decomposition for regulating decomposition of agricultural waste litter.

Soil microorganisms, which include many rare taxa and a small number of abundant taxa, have different contributions to the ecosystem functions and services. High throughput sequencing technology was used to analyze the species composition of soil samples by DNA sequencing. Soil microorganisms were divided into abundant taxa and rare taxa to reveal their composition. Correlation analysis and random forest method were used to further analyze the influence of environmental factors on the community. Finally, the beta nearest taxon index (βNTI) based on the null model was used to elucidate the mechanisms underlying soil microbial community assembly. We found that, in desert soil, the community assembly of rare bacteria was almost entirely dominated by a homogeneous selection of deterministic processes. For comparison, stochastic processes had more pronounced effects on the abundant bacteria. However, both abundant and rare fungi exhibited similar patterns of community assembly, i.e. deterministic and stochastic processes jointly determined the assembly processes of fungal communities. We also observed that community assembly shifted from stochastic to deterministic processes with increasing mean annual precipitation (MAP) and mean annual temperature (MAT) for abundant bacteria. Conversely, for rare fungi, there was an inclination toward a shift from deterministic to stochastic processes with rising MAT. In conclusion, our findings provide compelling evidence that MAT and MAP regulate the community assembly process of abundant and rare microbial communities in desert soil. These findings establish a theoretical foundation for future investigations into the community structure and ecological functions of soil microorganisms.

The theory of microbial stoichiometry can predict the proportional coupling of microbial assimilation of carbon (C), nitrogen (N), and phosphorus (P). The proportional coupling is quantified by the homeostasis value (H). Covariation of H values for C, N, and P indicates that microbial C, N, and P assimilation are coupled. Here, we used a global dataset to investigate the spatiotemporal dynamics of H values of microbial C, N, and P across biomes. We found that land use and management led to the decoupling of P from C and N metabolism over time and across space. Results from structural equation modeling revealed that edaphic factors dominate the microbial homeostasis of P, while soil elemental concentrations dominate the homeostasis of C and N. This result was further confirmed using the contrasting factors on microbial P vs. microbial C and N derived from a machine-learning algorithm. Overall, our study highlights the impacts of management on shifting microbial roles in nutrient cycling.

glmm.hp is an R package designed to evaluate the relative importance of collinear predictors within generalized linear mixed models (GLMMs). Since its initial release in January 2022, it has been rapidly gained recognition and popularity among ecologists. However, the previous glmm.hp package was limited to work GLMMs derived exclusively from the lme4 and nlme packages. The latest glmm.hp package has extended its functions. It has integrated results obtained from the glmmTMB package, thus enabling it to handle zero-inflated generalized linear mixed models (ZIGLMMs) effectively. Furthermore, it has introduced the new functionalities of commonality analysis and hierarchical partitioning for multiple linear regression models by considering both unadjusted R₂ and adjusted R₂