Invertebrates and microorganisms are important but climate-dependent agents of wood decomposition globally. In this meta-analysis, we investigated what drives the invertebrate effect on wood decomposition worldwide. Globally, we found wood decomposition rates were on average approximately 40% higher when invertebrates were present compared to when they were excluded. This effect was most pronounced in the tropics, owing mainly to the activities of termites. The invertebrate effect was stronger for woody debris without bark as well as for that of larger diameter, possibly reflecting bark- and diameter-mediated differences in fungal colonisation or activity rates relative to those of invertebrates. Our meta-analysis shows similar overall invertebrate effect sizes on decomposition of woody debris derived from angiosperms and gymnosperms globally. Our results suggest the existence of critical interactions between microorganism colonisation and the invertebrate contribution to wood decomposition. To improve biogeochemical models, a better quantification of invertebrate contributions to wood decomposition is needed.

Tropical forests constitute the world's largest biomass carbon pool and are important global reservoirs of biodiversity, yet they are being increasingly degraded by anthropogenic activities. Evidence from American tropical forests suggests that forest disturbance and climate change result in increased liana abundance and biomass, but data are still lacking from African and Asian forests. An increasing abundance of lianas may affect forest ecosystem services, which is concerning as these services are poorly understood. Recognizing the urgent need to evaluate how increases in lianas could affect local and regional carbon, nutrient, and water cycles, 35 scientists (Fig. 1), at different career stages, from 14 countries working across Africa, America, and Asia, convened at the 1st International Workshop on Liana Forest Ecology held at Xishuangbanna Tropical Botanical Garden (XTBG), China, 12–16 October 2023. With the focus 'From life to afterlife: liana proliferation and its consequences for carbon and water cycling', the workshop discussed how carbon, nutrient, and water cycles are affected by: (1) drivers of liana distribution and demography; (2) hydraulics of lianas vs trees; (3) lives of lianas; and, (4) afterlives of lianas (Fig. 2). Here, we provide a summary of our discussions. S. A. Schnitzer (Marquette University, USA), R. T. Corlett (Xishuangbanna Tropical Botanical Garden, China), and B. Ofosu-Bamfo (Kwame Nkrumah University of Science and Technology, Ghana) provided overviews of liana research in the Americas, Asia, and Africa, respectively. Most quantitative research has occurred in the Americas, but there is increasing effort in other continents. S.A. Schnitzer highlighted recent work, which shows that lianas reach high density and diversity in tree fall gaps in the tropics and can suppress trees and other growth forms. He noted that information on liana demography using established sampling protocols is critical to reveal the age and size classes where lianas are thriving, and provides a way to compare the potential causes of liana increases among sites. Such censuses must be further expanded to sites in Africa, Australia, and Asia. In the latter region, a combination of such censuses with in-depth studies will also contribute to better insights into the ecology of rattans, a diverse and commercially important group of climbing palms (R. T. Corlett). Understanding hydraulic differences between trees and lianas is critical to explaining both their competitive interactions and their impacts on soil–water resources. Lianas have, on average, wider vessel diameters and greater lengths than trees, resulting in more efficient hydraulic transport and potentially greater vulnerability to embolism (Smith-Martin et al., 2022). However, studies with refined methods, including X-ray micro-computed tomography, optical vulnerability techniques, and improved bench-top dehydration methods to assess dehydration-induced embolism, have shown that lianas are more resistant to embolisms than previously thought (Chen et al., 2021; Smith-Martin et al., 2022; K. Cao, Guangxi University, China). This may be because of the wider distribution of xylem vessel diameters in lianas compared with trees: small vessels can continue to transport water even after larger vessels have been embolized (Smith-Martin et al., 2022; Zhang et al., 2023). There was debate during the workshop about the possible mechanisms, leading to the conclusion that the refilling of embolized vessels is not supported by concrete evidence. C.M. Smith-Martin (University of Minnesota, USA) suggested that more comparative studies on xylem anatomy, examining pit membrane thickness and xylem vessel connectivity, are needed to establish whether large vessels are isolated from the smaller vessels in lianas, as this would prevent the propagation of embolisms, with implications for water cycling. Lianas perform better than trees during seasonal drought, with higher photosynthetic rates, fewer negative predawn leaf water potentials, and higher growth rates than trees (Schnitzer & van der Heijden, 2019; Smith-Martin et al., 2019). C.M. Smith-Martin pointed out that, although this difference was previously ascribed to lianas having deeper roots than trees, stable isotopic studies revealed deep or shallow water use by lianas relative to trees. Meanwhile, excavation studies reported no difference in rooting depth among juvenile lianas and trees, but a greater depth of mature trees than lianas (Smith-Martin et al., 2019, 2020). C.M. Smith-Martin also noted that rooting depth is likely species- and site-specific, so further root excavation studies are needed. If lianas are not accessing deeper sources of water, then they must rely on other mechanisms to outperform trees during seasonal drought. Potential explanations include that lianas lower their leaf turgor loss point during the dry season to increase drought resistance (S.A. Schnitzer, Marquette University, USA), and/or have peak photosynthetic rates early in the morning when vapor pressure deficit is low (Chen et al., 2017). K. Tomlinson (Xishuangbanna Tropical Botanical Garden, China) suggested that controlled dry-down experiments would yield critical data on leaf physiological responses of lianas and trees to soil drying. Talks on seed, seedling, and adult liana diversity emphasized that studies to date typically focused on few species, whereas the rare examples of community assessment show the great diversity of liana life forms. Those analyses suggest that lianas should not be treated as a single functional type when understanding forest community dynamics. M. Roeder (Karlsruhe Institute of Technology, Germany) reported a large range of seed traits and germination requirements in an Amazonian forest community. She also reported on seedling traits, which were related to remarkable differences in the life histories of lianas from different forest types. Under a closed canopy primary forest, lianas can form free-standing seedling or sapling banks (often by clonal vegetative reproduction). In secondary forests, with increased light availability, liana vegetative regeneration increases in importance and growth. Associated traits were more heterogenous than in primary forests. M. Roeder advocated expanding trait-based liana community analyses to generate a deeper understanding of the functional ecology of lianas across forest types, further pointing out that biometric analyses of seeds can provide a large amount of information without the need for resource-intensive germination tests. G. Zotz (Carl von Ossietzky University, Germany) advocated a more holistic approach to growth forms. He noted that herbaceous vines are understudied, and further concluded that ecologists should avoid treating 'woody lianas', 'herbaceous vines', and 'epiphytes' as homogenous functional groups, a sentiment that has been put forward elsewhere (e.g. Meunier et al., 2021; Schnitzer & Carson, 2023). Liana reproductive phenology is important for plant and animal community dynamics, as flowers and fruits are important animal food resources. Liana reproductive phenology ranges from seasonal to aseasonal depending on dry season length; in seasonal environments with asynchrony in reproductive phenology between trees and lianas, lianas may provide critical fallback resources for animals. Unfortunately, there are few studies on liana phenology and they are mostly from the American tropics; most do not quantify flower and fruit resources over time, which is critical to understanding their contribution to ecosystem functions and services. At the meeting, two recent studies from Asia and Africa were reported. In an Asian seasonal forest, peak flowering coincided in the late dry season between trees and lianas, but lianas produced more flowers earlier in the dry season (T.C. Ling, Chiang Mai University, Thailand), which contrasts with asynchrony between the growth forms in seasonal forests in Mexico (Cortés-Flores et al., 2017). In two African seasonal forests, liana flowering peaked twice per year in the wetter forest and only once in the drier forest, corresponding with the rainfall patterns of each forest (B. Ofosu-Bamfo). Remote sensing and on-site cameras may rapidly increase the spatial and temporal coverage of phenological studies (e.g. Kaçamak et al., 2022), allowing future research to establish how abiotic (e.g. rainfall, seasonality) and biotic factors (e.g. phylogeny and pollinator guilds) influence liana phenology. The contributions to carbon and nutrient cycling of litter generated from lianas vs trees remain poorly documented. M. Roeder highlighted the lack of community-level studies on litterfall and decomposition of lianas vs trees and presented evidence (including higher leaf nitrogen content) that leaves of lianas consistently decompose faster than trees in a multi-community study (Roeder et al., 2022). This corresponded with experimental evidence from temperate species reported by H. Cornelissen (Vrije Universiteit Amsterdam, the Netherlands). J. Zuo (Wuhan Botanical Garden, China) suggested that differences in litter quality sourced from lianas and trees offer an opportunity to test some ecological hypotheses such as mixture effect mechanisms. D. Schaefer (Kunming Institute of Botany, China) pointed out that wood and leaf decomposition studies, in general, have been performed separately, and that future decomposition studies should include leaf and wood litter mixtures. Liana wood decomposition is thought to be enhanced by its low wood density, and large-diameter and long xylem vessels allowing fungal hyphae to proliferate and invertebrates to invade. Due to differences in liana woody debris nutrient content compared with trees, the two growth forms could host different communities of invertebrate decomposers. G.G.O. Dossa (Xishuangbanna Tropical Botanical Garden, China) expected invertebrate contribution to liana woody debris decomposition to be higher in magnitude compared with tree woody debris, and H. Cornelissen proposed that the role of termites should be considered in future studies. Termites are quite selective for food quality; thus, deadwood studies will provide more insights if they include anti-termite cages. Furthermore, since some of the decaying material remains suspended in the forest canopy, studies should quantify this suspended portion of decaying litter and compare ground vs suspended woody debris for (abiotic and biotic contributions to) decomposition (G.G.O. Dossa). The increase in liana density and basal area is one of the major changes now occurring in many tropical forests and was a central theme of the workshop. The potential ramifications of increasing liana density illuminated the need for a deeper understanding of the fundamental ecology of lianas. A more complete understanding of liana hydraulics and underlying traits may be critical to understanding their ability to efficiently move more water from the soil to their sun-exposed leaves. Resolving where lianas access water in the soil profile, the amount of water they take up, and how these vary with climate and soils, remains a priority area of research. Leaf phenology and the afterlives of lianas are clear gaps in our general understanding of the contribution of lianas to ecosystem services and nutrient cycling in forests. Liana stem and leaf properties differ from those of trees, making unique contributions to forest soil dynamics. Thus, the contribution of lianas to decay rates of dead plant matter and their interactions therein with tree-derived deadwood and litter are understudied but potentially important to understanding forest ecology. One key outcome of this workshop is the acknowledgement that insight can be gained by merging analyses of species-level functional traits of wide-ranging lianas and trees, with those of community-level plant and decomposer composition, demography, and matter cycling. This will likely be a key theme to be addressed in a follow-up workshop (potentially in Beijing in 2025). The participants of the workshop are grateful for financial support from the Chinese Academy of Sciences and Xishuangbanna Tropical Botanical Garden. In addition, G.G.O.D. was supported by the Yunnan provincial government talents program (E1YN101B01). G.G.O.D. and J.Z. were supported by Open Funding from CAS Key Laboratory of Tropical Forest Ecology (22-CAS-TFE-06).

Concrete structures are some of the largest constructions in human civilization. Their manufacture releases CO2 into atmosphere, which is partially readsorbed by standing structures, and further release occurs when they are demolished. Concrete is chemically similar to basaltic minerals, both adsorb CO2 where they are exposed on the earth's surface. Sequestration of CO2 is beneficial to reduce atmospheric concentrations, and thus limit future temperature increases. Therefore, multiple options are being examined for CO2 sequestration. For the first time, we compare the CO2 sequestration capacity of these two materials. We review previous work quantifying CO2 sequestration capacity of both materials and for the first time, compare their potential quantitative roles. Costs of that are compiled, to the extent they have been examined. Costly grinding of these materials to small particle sizes accelerates CO2 sequestration, and mycorrhizae in agricultural soils might reduce the associated costs. Both these materials can improve nutrient status in agricultural soils, and limit acidification from external nitrogen fertilization. Limitations are discussed in terms of land-use and material availability, and soil pH conditions. We call for further experiments with these materials that compare CO2 sequestration and other biogeochemical processes in agricultural systems across climates, carried out especially where such materials are conveniently available.

Climate change and other anthropogenic disturbances are increasing liana abundance and biomass in many tropical and subtropical forests. While the effects of living lianas on species diversity, ecosystem carbon, and nutrient dynamics are receiving increasing attention, the role of dead lianas in forest ecosystems has been little studied and is poorly understood. Trees and lianas coexist as the major woody components of forests worldwide, but they have very different ecological strategies, with lianas relying on trees for mechanical support. Consequently, trees and lianas have evolved highly divergent stem, leaf, and root traits. Here we show that this trait divergence is likely to persist after death, into the afterlives of these organs, leading to divergent effects on forest biogeochemistry. We introduce a conceptual framework combining horizontal, vertical, and time dimensions for the effects of liana proliferation and liana tissue decomposition on ecosystem carbon and nutrient cycling. We propose a series of empirical studies comparing traits between lianas and trees to answer questions concerning the influence of trait afterlives on the decomposability of liana and tree organs. Such studies will increase our understanding of the contribution of lianas to terrestrial biogeochemical cycling, and help predict the effects of their increasing abundance.

Decomposition rates of litter mixtures reflect the combined effects of litter species diversity, litter quality, decom-posers, their interactions with each other and with the environment. The outcomes of those interactions remain am-biguous and past studies have reported conflicting results (e.g., litter mixture richness effects). To date, how litter diversity and soil fauna interactions shape litter mixture decomposition remains poorly understood. Through a sixteen month long common garden litter decomposition experiment, we tested these interaction effects using litterbags of three mesh sizes (micromesh, mesomesh, and macromesh) to disentangle the contributions of different fauna groups categorized by their size at Wuhan botanical garden (subtropical climate). We examined the decomposition of five single commonly available species litters and their full 26 mixtures combination spanning from 2 to 5 species. In total, 2325 litterbags were incubated at the setup of the experiment and partly harvested after 1, 3, 6, 9, and 16 months after exposure to evaluate the mass loss and the combined effects of soil fauna and litter diversity. We predicted that litter mixture effects should increase with increased litter quality dissimilarity, and soil fauna should enhance litter (both single species litter and litter mixtures) decomposition rate. Litter mass loss ranged from 26.9 % to 87.3 %. Soil fauna access to litterbags accelerated mass loss by 29.8 % on average. The contribution of soil mesofauna did not differ from that of soil meso-and macrofauna. Incubation duration and its interactions with litter quality dissimilarities together with soil fauna determined the litter mixture effect. Furthermore, the litter mixture effect weakened as the decomposition progresses. Faunal contribution was broadly additive to the positive mixture effect irrespective of litter species richness or litter dissimilarity. This implies that combining the dissimilarity of mixture species and contribu-tions of different soil fauna provides a more comprehensive understanding of mixed litter decomposition.

Currently, maize (Zea mays L.) production is under threat from climate change, drought, and pests such as fall armyworm (FAW) [Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)]. Since its first detection outside of its native range in 2016, FAW has spread into 76 nations across Africa and Asia adversely affecting maize production and, in turn, the livelihoods of millions of smallholder farmers. Thus, there is a strong need for the development of cost-effective and biologically based integrated pest management (IPM) practices including host-plant resistance (HPR). However, most of the commercial maize cultivars have lost some defensive traits through selective breeding for yield during domestication. The majority of the commercially cultivated hybrids and cultivars in Asia and Africa are highly susceptible to FAW. Therefore, this review summarizes information about various maize landraces, native germplasm, and crop wild relatives (CWRs) possessing FAW resistance traits and about their potential resistance mechanisms, namely antibiosis, antixenosis, and tolerance. There is clear evidence of FAW resistance acting through diverse mechanisms in several maize landraces, germplasm lines, native populations, and CWRs such as Antigua race, FAW Tuxpeno, Zapalote Chico 2451F, Doce Flor da Serra, FAWCC (C5), CMS 14C, PopG (C2), MpSWCB-4, Mp708, Mp 704, CML 67, and FAW 7050, as well as a few species of teosinte and Tripsacum L. Further, a scheme that outlines strategies and approaches for prebreeding and their introgression into elite cultivars for developing FAW-resistant maize is proposed as a possible way forward.

Arbuscular mycorrhizal fungi (AMF) provide benefits to most crop species via enhanced nutrient uptake, increased drought and abiotic stress resistance, and reduced effects of pathogens and pests. Much remains unclear regarding the specific mechanisms influencing these processes, and the critical roles of AMF are often overlooked in planning agroecological systems. There is growing consensus, however, around the important roles AMF play in improving plant resilience and crop yield while also enhancing the functioning of soil microbial communities. Heterogeneous practices across all scales complicate the successful integration of AMF in agroecological systems. AMF symbioses with crops are passive, or stimulated by incorporation of crop wastes in soil, soil inoculation with AMF spores, or the planting inoculated of seeds. Here we suggest that AMF can have highest beneficial impacts in areas with low levels of agrochemical inputs. We argue that areas with intensive agrochemical inputs can also be made more sustainable with AMF enhancements.

Background: Fungi are essential agents in decomposing woody debris (WD), an important carbon pool in forests. However, the ecology and dynamics of these fungal communities are poorly understood, especially in tropical forests. A better understanding of anthropogenic impacts, such as forest disturbances, on WD decomposition is also needed to appreciate their consequences on ecosystem functioning. Here, we examined the impacts of forest degradation and roles of fungal diversity and composition on WD decomposition rates across a disturbance gradient in a tropical montane rain forest in Xishuangbanna, SW China over three years. We measured wood specific gravity (WSG) loss from 280 logs from Litsea cubeba (low-WSG) and Castanopsis mekongensis (high-WSG). We concomitantly monitored fungal communities from 418 samples using next-generation sequencing after 0, 18 and 36 months field exposure. Results: Incubation time, habitat and termite presence were key drivers of fungal community composition. Fungal community succession showed a priority effect of precedent communities. C. mekongensis WD consistently harbored ~1.4 times less fungal species than L. cubeba , but had ~1.4 times more unique operational taxonomic unit (OTU) at 18 mo. Shared OTUs between wood species increased with time up to ~63 % at 36 mo. Regardless of wood species, fungal diversity and both saprotrophs and white-rot abundances peaked at 18 months. However, fungal diversity was not a significant predictor of WSG loss. WSG loss did not vary among habitats. This may result from compensatory changes in dominant functional traits, such as decay mechanisms (e.g., proportion of white rot-fungi, soft-rot fungi). For example white- rot fungal proportions were double in open land compared to mature forest. Likewise, more saprothrophs colonized high-WSG wood. Finally, ascomycetes (mainly Sordariomycetes and Dothiodeomycetes) and basidiomycetes (mostly Agaricomycetes) were dominant fungal groups. Open land was dominated by Trichoderma, regenerating forest by Herpothrichiellaceae and mature forest by Penicillium . Conclusions: White- and soft-rot fungi co-dominated decomposition, with the later increasing through time. A succession of different fungal functional groups yielded similar decomposition rates across the disturbance gradient. Incorporating dominant fungal functional trait dynamics into biogeochemical models may improve predictions of carbon dynamics.

Insects first began evolving hundreds of millions of years ago, and aided by gut microbes, they have been consuming hydrocarbon polymers ever since. Few man-made plastic polymers are chemically novel, so it is reasonable that insect/microbe systems can be found or developed to degrade them rapidly. However, remediation of global plastic waste problems should involve more than just conversion into CO2. Some industry-scale microbial enzymatic degradation of plastic polymers may yield valuable monomers, but the plastic waste starting material must be of uniform chemistry and clean. This adds cost to the process. Many insect species can be utilized for animal feed as well as human food. Some of these insects have the capability to degrade plastic polymers. However, valorizing plastic wastes by producing edible insects or useful frass has largely been overlooked. Here we assemble the current knowledge of plastic degradation rates by insects. In addition, we also show the first instance of insect degradation of polyurethane and the first identification and isolation of insect gut fungi as directly aiding insect degradation.

Climate change will affect numerous crops in the future; however, perennial crops, such as tea, are particularly vulnerable. Climate change will also strongly influence fungal pathogens. Here, we predict how future climatic conditions will impact tea and its associated pathogens. We collected data on the three most important fungal pathogens of tea (Colletotrichum acutatum, Co. camelliae, and Exobasidium vexans) and then modeled distributions of tea and these fungal pathogens using current and projected climates. The models show that baseline tea-growing areas will become unsuitable for Camellia sinensis var. sinensis (15 to 32% loss) and C. sinensis var. assamica (32 to 34% loss) by 2050. Although new areas will become more suitable for tea cultivation, existing and potentially new fungal pathogens will present challenges in these areas, and they are already under other land-use regimes. In addition, future climatic scenarios suitable range of fungal species and tea suitable cultivation (respectively in CSS and CSA) growing areas are Co. acutatum (44.30%; 31.05%), Co. camelliae (13.10%; 10.70%), and E. vexans (10.20%; 11.90%). Protecting global tea cultivation requires innovative approaches that consider fungal genomics as part and parcel of plant pathology.

Woody debris represents a substantial reservoir of carbon in forests. Disentangling the effects of factors affecting wood decomposition rates is therefore important. We examined the abiotic and biotic factors affecting wood decomposition across a disturbance gradient from mature forest to open land in a tropical montane site in Xishuangbanna, SW China. Wood logs (n = 280) of two native species with contrasting wood specific gravity (WSG), Castanopsis mekongensis (0.75) and Litsea cubeba (0.42), were exposed on the ground for three years. For each log, WSG was monitored at intervals by taking cores from top-half (up) and bottom-half (down) of the log. Mass loss was measured at the end of the experiment. WSG loss rates were similar across the disturbance gradient and the species effect varied with core position. For Castanopsis, which had higher initial WSG and wood N concentration and much thicker bark, up-cores had consistently higher WSG loss over the study period. This species also had substantially higher WSG loss for up-cores, but interspecific difference among down-cores was small. For mass loss, there was a complex interaction between species, habitat and the presence of termites. Litsea with low initial WSG experienced approximately two-fold higher mass loss in the absence of termites, but the difference between species was smaller in the presence of termites. Both species experienced higher mass loss in open habitats than in forests, but the termite effect was smaller in open habitats especially for Litsea. There was no interspecific difference in susceptibility to termite infestation, but infestation rates were higher in regenerating forests and open land than in mature forest. WSG loss explained 0% and 19% of mass loss variation in Listea and Castanopsis, respectively, in absence of termites and 0% for both in the presence of termites. Afterlife effects of wood functional traits interact with abiotic conditions and decomposition processes (microbial decomposition, macro-organisms (termites), photo-degradation) in a complex manner to determine wood decomposition rates. WSG loss is not a reliable predictor of mass loss. These results have important implications for understanding the carbon cycle in tropical landscapes that are undergoing anthropogenic disturbance.

Polyurethanes (PU) are integral to many aspects of our daily lives. Due to the extensive use of and difficulties in recycling or reusing PU, it mostly accumulates as waste. Various bacteria and fungi have been reported to degrade PU. We examined the fungus Aspergillus flavus G10 in that regard, after isolating it from the guts of Gryllus bimaculatus , a common cricket species. We observed surficial and chemical changes of PU with atomic force microscopy, scanning electron microscopy, and attenuated total reflectance Fourier-transform infrared spectroscopy. We measured physical changes as loss in tensile stress, stretching force, and weight of PU after incubations. Fungal hydrolysis of urethane bonds in the polymer backbone was demonstrated by detecting the formation of methylene di-aniline during incubations. Trapped CO 2 during incubations equaled 52.6% of PU carbon. Biodegradation of PU was maximal by fungi cultured on a malt extract medium at 25 °C, pH 12, and 14:10 hrs light to dark ratio. Pretreating PU films with UV light or 1% FeSO 4 or NaCl solutions further enhanced the rate of biodegradation. A range of techniques are needed to fully characterize the degradation of PU or other plastic polymers and to optimize conditions for their microbial degradation.

The mechanisms underlying soil organic carbon (C) dynamics during forest succession remain challenged because amount, quality, and composition of C inputs change with tree growth and species composition. Soils were collected from two stages (grassland and young secondary forest) of secondary succession after the clear-cut of primary old-growth forest due to land-use change, with a native old-growth forest (undisturbed for more than 200 years) as the reference. Soil samples were incubated for 170 days and the priming effects were quantified by one pulse addition of 13C-labeled glucose. 13C-PLFAs (phospholipid fatty acids) were analyzed to identify microbial functional groups utilizing glucose and to explore their accordance with SOM priming during succession. Soil C was primed much more strongly in young secondary forest than in grassland or old-growth forest. Priming resulted in large C losses (negative net C balance) in young-forest soil, whereas C stocks increased in grassland and old-growth forest (positive net C balance). Microbial composition assessed by PLFA and utilization of easily available organics (13C-PLFA) indicated that fungi were mainly responsible for priming in young-forest soil. Consequently, labile C released by litter decomposition and root exudation together with the availability of soil nutrients determines microbial functional groups that decompose soil organic matter during initial succession. These findings provide novel ecological connections between soil organic matter dynamics and C (de)stabilization with microbial functioning during forest succession and show that priming direction and intensity is important to distinguish soil C dynamics in young- and old-growth forests.

Woody debris (WD) represents a globally significant carbon stock and its decomposition returns nutrients to the soil while providing habitat to microbes, plants and animals. Understanding what drives WD decomposition is therefore important. WD decomposition rates differ greatly among species. However, the role of bark in the process remains poorly known. We ask how, and how much, interspecific variation in bark functional traits related to growth and protection have afterlife effects on the decomposition of wood, partly mediated by animals. We examine the roles of bark cover and bark traits throughout the wood decomposition process. Synthesis. We find that: (1) bark effects on WD decomposition are species‐ and wood size‐specific, (2) bark can enhance coarser WD decomposition but slows twig decomposition in some species, and (3) bark acts as an environmental filter to faunal assemblages in the early stage of wood decomposition.

Understanding mechanisms of successful colonization by exotic plant species in non-native habitat is critical to meet long-term restoration aims. Overgrowing plants can alter resources, especially soil inorganic nitrogen availability and get benefits from positive feedback. However, comprehensive knowledge on particular mechanisms underlying their successful colonization remains unclear. Here, field examinations and laboratory manipulations were combined to investigate significant impact of overgrowing Ageratina adenophora on soil NO3-N availability and nitrification. Interestingly, we found significant enhancement in soil total N, NO3--N, pH, potential nitrification rates, and ammonia oxidizing bacteria (AOB), while reduced abundance of ammonia oxidizing archaea (AOA) under the influence of A. adenophora. Notably, AOB abundance was positively correlated with both pH and soil potential nitrification rates. AOA abundance was negatively correlated with pH and had no significant correlation with soil nitrification potential. Both AOA and AOB communities significantly differed between populated and non-populated soils. pH was the strongest factor contributing to this community difference. We conclude that A. adenophora stimulates nitrification with the help of AOB rather than AOA under relatively higher soil pH condition. (C) 2017 Elsevier Ltd. All rights reserved.

The ratio of intercellular to ambient CO2 concentrations (c i/c a) plays a key role in ecophysiology, micrometeorology, and global climatic change. However, systematic investigation on c i/c a variation and its determinants are rare. Here, the c i/c a was derived from measuring ecosystem fluxes in an even-aged monoculture of rubber trees (Hevea brasiliensis). We tested whether c i/c a is constant across environmental gradients and if not, which dominant factors control c i/c a variations. Evidence indicates that c i/c a is not a constant. The c i/c a exhibits a clear "V"-shaped diurnal pattern and varies across the environmental gradient. Water vapor pressure deficit (D) is the dominant factor controls over the c i/c a variations. c i/c a consistently decreases with increasing D. c i/c a decreases with square root of D as predicted by the optimal stomatal model. The D-driving single-variable model could simulate c i/c a as well as that of sophisticated model. Many variables function on longer timescales than a daily cycle, such as soil water content, could improve c i/c a model prediction ability. Ecosystem flux can be effectively used to calculate c i/c a and use it to better understand various natural cycles.

Organic matter decomposition represents a vital ecosystem process by which nutrients are made available for plant uptake and is a major flux in the global carbon cycle. Previous studies have investigated decomposition of different plant parts, but few considered bark decomposition or its role in decomposition of wood. However, bark can comprise a large fraction of tree biomass. We used a common litter-bed approach to investigate factors affecting bark decomposition and its role in wood decomposition for five tree species in a secondary seasonal tropical rain forest in SW China. For bark, we implemented a litter bag experiment over 12 mo, using different mesh sizes to investigate effects of litter meso- and macro-fauna. For wood, we compared the decomposition of branches with and without bark over 24 mo. Bark in coarse mesh bags decomposed 1.11–1.76 times faster than bark in fine mesh bags. For wood decomposition, responses to bark removal were species dependent. Three species with slow wood decomposition rates showed significant negative effects of bark-removal, but there was no significant effect in the other two species. Future research should also separately examine bark and wood decomposition and consider bark-removal experiments to better understand roles of bark in wood decomposition.

Decomposition of organic matter (OM) in soil, affecting carbon (C) cycling and climate feedbacks, depends on microbial activities driven by C and nitrogen (N) availability. However, it remains unknown how decomposition of various OMs vary across global supplies and ratios of C and N inputs. We examined OM decomposition by incubating four types of OM (leaf litter, wood, organic matter from organic and mineral horizons) from a decay continuum in a subtropical forest at Ailao Mountain, China with labile C and N additions. Decomposition of wood with high C:N decreased for 3.9 to 29% with these additions, while leaf decomposition was accelerated only within a narrow C:N range of added C and N. Decomposition of OM from organic horizon was accelerated by high C:N and suppressed by low C:N, but mineral soil was almost entirely controlled by high C:N. These divergent responses to C and N inputs show that mechanisms for priming (i.e. acceleration or retardation of OM decomposition by labile inputs) vary along this decay continuum. We conclude that besides C:N ratios of OM, those of labile inputs control the OM decay in the litter horizons, while energy (labile C) regulates decomposition in mineral soil. This suggests that OM decomposition can be predicted from its intrinsic C:N ratios and those of labile inputs.