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Plant functional traits are increasingly used to understand ecological relationships and (changing) ecosystem functions. For understanding ecosystem-level biogeochemistry, we need to understand how (much) traits co-vary between different plant organs across species and its implications for litter decomposition. However, we do not know how the degree of synchronous variation in decomposition rates between organs across species could be influenced by different keystone invertebrates decomposing different senesced plant organs, especially in warm-climate forests. Here we asked whether interspecific patterns in wood and leaf decomposition rates and in the spectra of resource economics traits underpinning them, co-vary across woody species; and how (much) the keystone invertebrate decomposers of the litter of these organs enhance or lower such co-variation of decomposition rates through time. We addressed these questions through an 18-month ‘common-garden’ decomposition experiment using leaf, twig and branch litter of 41 woody species in two distant subtropical forest sites in east China. We quantified the effects of leaf, twig and branch functional traits and their respective key invertebrates (moth larvae, termites) on the decomposition rates of those organs. Interspecific variation in wood traits was partly decoupled from that in leaf traits across species, while strong coupling was found between twigs and branches. The co-variation between leaf and woody organ decomposition rates was altered dynamically through the shifting activities of the key decomposers, which created nonlinear relationships of invertebrate litter consumption as a function of species rankings along the resource economic trait spectra of leaves and branches. The deviations from coupling of decomposition rates between organs were likely caused by combinations of three mechanisms: (1) (de-)coupling between organs of other traits, not commonly considered in resource economics spectra (e.g. resins)

Foliar nitrogen (N) or phosphorus (P) status and their stoichiometric homeostasis are integral parts of the plant nutrient economy that determines the success of plant species in environments where N or P limits plant growth. Despite growing evidence for higher predictability of stoichiometric homeostasis of N (HN) than that of P (HP) on plant species abundance in temperate grasslands, no previous studies explicitly examined how foliar N and P status modulate the relationships between stoichiometric homeostasis and species distribution (regional species abundance) of woody plants, especially in P-limited (sub)tropical ecosystems. We hypothesized that species with a conservative foliar nutrient status but a higher HP (but not HN) would be regional abundant in P-limited forest. We measured foliar N (LNC) and P (LPC) contents of 54 woody species, community composition and soil N and P contents across 94 forest plots in Chinese subtropical forests. Then we evaluated the species' levels of N and P stoichiometric homeostasis and their regional abundance to test our hypotheses. HN and HP significantly increased with decreasing LNC and LPC. Foliar nutrient status positively correlated with the minimum values of both soil N and P contents, but only negatively associated with the maximum value of soil P content, indicating that conservative species can occupy a wider range of soil P- than N-based nutrient niche. Meanwhile, species abundance negatively correlated with LNC and LPC, and positively correlated with HN and HP. However, the structure equation model analysis showed that species abundance increased with decline of LNC but not yet with increased HN. In contrast, species abundance enhanced with increased HP and decreased LPC via HP, rather than directly with a decline of LPC. Synthesis. This study provides empirical evidence that species with conse

Changes in the composition of plant functional traits may affect ecosystem processes through influencing trophic interactions. Bottom-up control by plant species through food availability to animals may vary with time. However, such dynamics and their consequences for deadwood turnover are poorly known for detrital food webs. We introduce a dynamic conceptual model of the feedback of tree functional traits, (deadwood-feeding) termite populations and deadwood decomposition. We hypothesized that tree functional diversity (in terms of a wood resource economic spectrum [WES]) supports the sustenance of termite populations via complementary food supplied through time, as deadwood varies in traits both initially across species and because of different decomposition rates. Simultaneously, driven by this temporal dynamics of food quality, the consumption of deadwood by termites should hypothetically sustain deadwood turnover in a functionally diverse forest over time. We tested our hypothesis through an 18-month termite-exclusion decomposition experiment by incubating coarse (i.e. 5 cm diameter) deadwood of 34 woody species in two subtropical forests in East China. One site still sustained a healthy population of pangolins as the keystone termite predator, whereas another had lost its pangolins due to hunting and illegal wildlife trade. The results supported our hypothesis: in the first 12 months, termites amplified the positive linear relationship between % wood mass loss and initial wood quality (WES). In contrast, between 12 and 18 months, termite-mediated consumption, and associated wood mass loss, showed a humpback relation with the initial WES. This shift in termite preference of deadwood species along the WES reflects complementary food availability to termites through time. Synthesis. Our findings imply that tree functional composition, with variation in deadwood quality through decomposition time, can help to sustain termite populations and thereby forest carbon

1. Subordinate species have relatively low abundance compared to dominant species; however, they may contribute significantly to functional diversity and ecosystem functionality, particularly if they differ strongly from the dominants in key traits. Here we investigated whether this phenomenon might be applied to litter decomposition as a key carbon and nutrient cycling process. 2. We hypothesized that species litter mass‐weighted predictions of community‐level litter decomposition based on dominant rates only, would deviate strongly from observed community‐level rates, and that predictions would improve as subordinates with strongly contrasting traits were combined with those of their dominant counterparts. 3. We tested this hypothesis through a 1‐year field decomposition experiment across a chronological sequence in a subtropical evergreen broadleaved forest. The experiment included the single‐species litter of evergreen dominants, evergreen subordinates and deciduous subordinates, respectively, as well as community‐level litter mixtures. 4. The expected community‐weighted mean decomposition rates based on the evergreen dominants alone, with or without the addition of evergreen subordinates, deviated strongly from those of observed community litter mixtures at the middle and late succession stages, but not at the early stage. When adding deciduous subordinates to this expectation, there was no longer any difference to the observed community litter decomposition rate across succession stages. Deciduous subordinates alone explained 7%, 21% and 15% of the total variation in community litter mixture decomposition rate for early, middle and late successional stages, respectively, which is more than would be expected from their litter mass fraction. 5.Synthesis. Deciduous subordinates with strongly contrasting nutritional and water‐storage traits compared to the dominant evergreens significantly impacted litter decomposition at the community‐level i

Litter quality and decomposers are critical to carbon and nutrient cycling through litter decomposition. However, how relationships between litter quality and invertebrate detritivores change litter mass loss through time is poorly known. Species’ initial leaf litter quality, as a legacy of their position on the ‘leaf economics spectrum’ (LES), may determine the invertebrate contribution to litter mass loss. This contribution may change through time, as both population peaks of invertebrate detritivores and litter quality of given species will change through time. Here we introduce invertebrate phenology into a conceptual model of drivers of litter mass loss. We hypothesized that in the early decomposition period, LES can predict litter decomposability with or without a strong invertebrate contribution, that is, litter with higher nutrient content would decompose faster. But in the later decomposition period, when higher quality litter will already have decomposed too much and lower quality litters have still been less degraded, a strong invertebrate peak would coincide with relatively more consumption of initially lower quality litters; this would lead to a humpback relationship between leaf litter mass loss and initial LES position in this period. We tested our hypothesis through a 1-year field decomposition experiment using leaf litter of 41 woody species in each of two sites in subtropical forest in China; only one of these sites had a strong late peak of leaf litter-feeding moth larvae in the litter layer. LES score of litter species had a positive linear relationship with litter mass loss before the key invertebrate consumer peaks in the litter layer. However, with the invertebrates peaking later into the decomposition process, the invertebrate consumption peaked at initially lower quality litters, which altered the species’ decomposability trajectory on the LES, consistent with the hypothesized humpback relationship between leaf litter mass loss and LES. T