Spines are a major ecological innovation supporting plant defence and diversification. Spine anatomy is diverse, having arisen in multiple plant lineages from many different plant organs and parts, which may differ in relative advantages across environmental gradients. Systematic analyses of the correlates of spiny plant diversity are limited, but climate and soil properties may be important. We analysed spatial patterns of the proportional richness of spiny woody plant species (fraction of total woody species richness) and the proportional richness of species with particular spine types (fraction of richness of spiny plants) across three regions with high plant geolocational data density spanning three continents, China (Asia), South Africa (Africa), and Australia. Spiny plants accounted for 12% of woody species, but there are strong phylogenetic biases in the evolution of spiny lineages and lineages bearing different spine types. The proportion of spiny plants increased towards drier environments and higher soil clay contents, and decreased towards soils with greater total N. Species bearing different spine types appear to be distributed differently across climate and soil gradients, suggesting trade-offs across productivity gradients, specialization for climate space, and constraints on environmental adaptability. The spatial richness of spiny plants was positively correlated with estimated historical richness of large herbivorous mammals (body mass >20 kg, diet >90% plant material), and species bearing different spine types also mostly show positive relationships with mammal richness. Plants with spines appear to be advantaged over non-spiny species when exposed to high mammal browsing pressure in arid environments or over certain soil conditions, and species bearing different spine types are differentially advantaged across climate and soil gradients.

Grassy vegetation is widely spread across Southeast Asia, yet very little data exists describing the diversity in these plant communities. Groundlayer diversity data is especially rare, with previous studies focussing on woody plants. Research in grassy ecosystems worldwide suggest that there are substantial differences in grassland community composition across climate aridity gradients, which are aligned with a switch from strong disturbance by fire in wetter sites to disturbance by mammalian herbivory in drier sites. The aim of this investigation was to record the groundlayer diversity of grasslands found in northern Sumatra Island, Indonesia, and to determine whether that diversity was structured fire and mammalian herbivory. We sampled ten 50 m x 50 m vegetation plots in grassy vegetation across an aridity gradient, with soil data and grazing pressure data collected on site, and climate and fire frequency data compiled from geographic resources. We classified all species according to two morphological characteristics that related to plant evolution under fire and herbivory, namely stem form and leaf placement. We recorded 89 groundlayer species across all plots, with an average of 29 species per plot. Our analysis confirmed that the strongest axis of community differentiation was with respect to the fire-grazing trade-off axis, which selected for specific adaptive stem and leaf placement morphologies. The groundlayer diversity of grasslands in northern Sumatra is closely related to other monsoonal regions of Southeast Asia, likely reflecting grassland connectivity during the last ice age. The abundance of disturbance-adapted species suggests appropriate use of fire and herbivory will be necessary to sustain these communities.

### Competing Interest Statement The authors have declared no competing interest. Deutsche Forschungsgemeinschaft, https://ror.org/018mejw64, DFG FZT 118, 202548816

Evolutionary radiation, a pivotal aspect of macroevolution, offers valuable insights into evolutionary processes. The genus Pinus is the largest genus in conifers with c.$$ c. $$ 90% of the extant species emerged in the Miocene, which signifies a case of rapid diversification. Despite this remarkable history, our understanding of the mechanisms driving radiation within this expansive genus has remained limited. Using exome capture sequencing and a fossil-calibrated phylogeny, we investigated the divergence history, niche diversification, and introgression among 13 closely related Eurasian species spanning climate zones from the tropics to the boreal Arctic. We detected complex introgression among lineages in subsection Pinus at all stages of the phylogeny. Despite this widespread gene exchange, each species maintained its genetic identity and showed clear niche differentiation. Demographic analysis unveiled distinct population histories among these species, which further influenced the nucleotide diversity and efficacy of purifying and positive selection in each species. Our findings suggest that radiation in the Eurasian pines was likely fueled by interspecific recombination and further reinforced by their adaptation to distinct environments. Our study highlights the constraints and opportunities for evolutionary change, and the expectations of future adaptation in response to environmental changes in different lineages.

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).

Trees structure the Earth's most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1-6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth's 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world's most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.

Dense branching and spines are common features of plant species in ecosystems with high mammalian herbivory pressure. While dense branching and spines can inhibit herbivory independently, when combined, they form a powerful defensive cage architecture. However, how cage architecture evolved under mammalian pressure has remained unexplored. Here we show how dense branching and spines emerged during the age of mammalian radiation in the Combretaceae family and diversified in herbivore-driven ecosystems in the tropics. Phylogenetic comparative methods revealed that modern plant architectural strategies defending against large mammals evolved via a stepwise process. First, dense branching emerged under intermediate herbivory pressure, followed by the acquisition of spines that supported higher speciation rates under high herbivory pressure. Our study highlights the adaptive value of dense branching as part of a herbivore defence strategy and identifies large mammal herbivory as a major selective force shaping the whole plant architecture of woody plants.

Plants have the ability to recognize their kin neighbors, which may be a beneficial trait that increases inclusive fitness, by suppressing individual growth to support the combined growth of the group. However, the advantages of kin cooperation (known as kin selection theory), may differ across environmental gradients, with competition between related individuals potentially being detrimental under resource limitation (following niche partitioning theory). The study aimed to understand how quinoa ( Chenopodium quinoa (Willd)) plants grow with kin or with non-kin under different nutrient supply rates. Plants were grown in treatments’ post-germination for 70 days. Biomass accumulation, allocation to organs, and organ traits related to resource acquisition were measured at the end of the experiment. Total mass and shoot mass were greater for plants grown with kin than with non-kin across nutrient treatments. Plants grown with kin had greater root allocation than with non-kin under low and high nutrients. Allocation to leaves, specific leaf area, and average leaf mass were greater for plants grown with non-kin than kin under high-nutrient supply, but did not differ under low-nutrient supply. Allocation to stem was greater for plants grown with kin than non-kin under high-nutrient supply, but did not differ under low-nutrient supply. Specific taproot length and specific stem length were respectively positively and negatively related to increased fertility, but unrelated to kinship. Our results suggest that both niche partitioning and kin selection processes may be at play in quinoa, depending on whether soil nutrient competition is more important. Under both situations, quinoa plants always grew better with kin than non-kin regardless of soil nutrient conditions.

Ants inhabit a vast range of ecosystems and exhibit wide morphology. They are expert navigators employing a handful of well-understood navigational strategies. However, the specific relationships among ant navigation behaviours, ecology, and morphology remain unclear, highlighting the need for comparative studies across diverse species. Here, we conducted field displacement experiments with 15 ant species across different habitats, assessing the prevalence of path integration, view-based navigation, olfactory trail following, and backtracking. We further tested whether use of particular navigation strategies was correlated with variation in morphological traits that could affect navigation efficiency, namely body size, eye size (view-based, path integration) and scape length (olfactory). There was a negative correlation between path integration and olfaction across different ant species, and no other clear trade-offs were identified between navigational strategies. Olfactory navigation emerged as the most dominant strategy. Path integration was also prevalent but limited to arboreal ants. View-based navigation was observed in both ground-foraging and tree-climbing ant species, and, unexpectedly, backtracking was also widespread. Species with larger eyes and body size showed a stronger preference for view-based navigation. However, no significant relationship was found between eye size or antennal scape length with preference for either path integration or olfaction. These results highlight the diversity and specialization of navigational strategies in ants, which appear to depend on the species' ecological niche and morphological traits. Our study confirmed that path integration performs better in open sky environments, while view-based navigation appears more effective in cluttered habitats. We also showed the importance of plasticity in both foraging strategies and navigational profile at individual and colony levels, demonstrating the adaptability of ants' navigation strategies to their environment. ### Competing Interest Statement The authors have declared no competing interest.

Southeast Asia (SEA) has seen strong climatic oscillations and fluctuations in sea levels during the Quaternary. The impact of past climate changes on the evolution and distribution of local flora in SEA is still poorly understood. Here we aim to infer how the Quaternary climate change affects the evolutionary process and range shifts in two pine species. We investigated the population genetic structure and diversity using cytoplasmic DNA markers, and performed ecological niche modeling to reconstruct the species past distribution and to project range shift under future climates. We found substantial gene flow across the continuous distribution of the subtropical Pinus yunnanensis. In contrast, the tropical Pinus kesiya showed a strong population structure in accordance with its disjunct distribution across montane islands in Indochina and the Philippines. A broad hybrid zone of the two species occurs in southern Yunnan. Asymmetric introgression from the two species was detected in this zone with dominant mitochondrial gene flow from P. yunnanensis and chloroplast gene flow from P. kesiya. The observed population structure suggests a typical postglaciation expansion in P. yunnanensis, and a glacial expansion and interglacial contraction in P. kesiya. Ecological niche modeling supports the inferred demographic history and predicts a decrease in range size for P. kesiya under future climates. Our results suggest that tropical pine species in SEA have undergone evolutionary trajectories different from high latitude species related to their Quaternary climate histories. We also illustrate the need for urgent conservation actions in this fragmented landscape.

Insect herbivory plays a crucial role in shaping plant communities in many terrestrial ecosystems. However, in African savannas, insect herbivory has been relatively understudied compared to large mammalian herbivory. In this study, we examined the impact of insect herbivory, focusing on leaf chewers and miners, in a South African savanna-forest mosaic (including patches of forest, thicket and savanna) in Hluhluwe iMfolozi Park, South Africa. Our investigation spanned gradients of rainfall, fire frequency and mammal density. We surveyed a total of 864 woody plants from 48 plant species in 38 plots. Insects consumed 6% of leaf biomass, which is comparable to their impact in temperate broadleaf forests, but the extent of herbivory damage varied between vegetation types. Overall, leaf loss was 70% higher in forests and savanna than that in thicket. Plants in the forests experienced greater damage from chewing insects, whereas miners caused relatively more damage in savannas. Rates of insect herbivory also varied among plant species, declining with carbon and dry matter content but increasing with specific leaf area. Although no significant trade-off was detected between insect and mammal herbivory, plant species with limited physical defences against mammals tended to experience high levels of insect herbivory. Our findings highlight the intricate dynamics of insect herbivory in different vegetation types and suggest that insect leaf herbivory, alongside mammalian herbivory, could play a significant role in influencing plant community composition and overall savanna ecosystem functioning.

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.

The role of trait variability in mediating plant community responses to environmental change remains poorly resolved. We conducted a 5-year study across 45 fragments in a tropical dry forest to understand shifts in trait means and variabilities of the trees classified into two functional types, drought avoiders and drought tolerators, across a soil moisture gradient, and their association with changes in site-level productivity. Trait means changed in opposite directions across the soil moisture gradient for the two functional types, especially for water safety and leaf carbon capture traits. Trait variabilities were generally greater at dry sites for drought avoiders and at wet sites for drought tolerators. Site-level growth rates were related to different sets of trait means and variabilities for the two functional types. Projected changes in precipitation will likely shift the vegetation to greater representation of drought tolerators and will be accompanied by non-linear increases in standing biomass.

The role of mammal herbivory in plant evolution is largely unrecognised. Spines on stems are a common and important feature found in ∼9% of eudicot woody plant species worldwide. Spines evolved independently multiple times during the Cenozoic. The timing and extent of spiny plant diversification varied among continents, pointing towards continental rather than global drivers. Spine evolution is closely related to radiation of extant ungulates and extinct ground sloths, rather than climate variation. Diversification began in the Paleogene in herbivore species-rich Eurasia and North America, emerging later in the Neogene in species-poorer South America, Africa and Australia. Spiny lineages expanded their ecological footprint over non-spiny plants, mainly through intercontinental migrations, indicating that spines likely provided a competitive advantage with increasing, and novel, mammal herbivory pressure.

In the natural environment, plants grow and interact with both conspecific and heterospecific neighbours under different environmental conditions. In this study, we tested whether Chenopodium quinoa Willd genotypes differ in growth performance when grown with kin and non-kin under nutrient limitation in pot partitioning treatments. Biomass accumulation, allocation, organ efficiency, and specific leaf area were measured at the end of the experiment. Response variables were differentially impacted by kinship, fertility, and barrier. Total dry mass, shoot dry mass, and root and stem allocation were greater for plants grown with kin in connected pots than with non-kin in connected pots across the nutrient treatments. Kin connected and disconnected plants had a greater specific root length, specific stem length, and average leaf mass than non-kin connected and disconnected plants. Non-kin connected and disconnected plants had greater LAR and SLA than kin connected and disconnected plants under low- and high-nutrient treatments. Plants always grew better in the presence of their kin than non-kin. These results conclude that quinoa plant production benefits from planting closely related individuals under both high- and low-nutrient conditions.

Plants utilize a mixture of defence types in response to herbivores, including physical, chemical, and biological defences. Among chemical defences, phenolics are well-known to inhibit digestion and are highly variable across plant species and resource gradients. There are prominent hypotheses predicting the potential change of phenolics in response to soil nutrients, but most focus on nitrogen (N) and none consider their interaction with defence strategies. We proposed an updated theoretical model that incorporates defence types and predicts their relative advantages under herbivore attack. We studied intraspecific leaf chemistry of several architecturally defended and non-architecturally defended species growing together across four sites with varying soil chemistry. We measured individual-level leaf concentrations of carbon, nitrogen, phosphorus (P), potassium (K), and phenolics, and site-level soil N, P, and K. We found that architectural defenders had lower phenolics and higher P than non-architectural defenders across locations. Relationships between soil nutrients and leaf chemistry were steeper in architectural defenders. Most leaf nutrients and phenolics showed significant relationships with soil P, and only leaf P was related to its respective soil resource. Within leaves, phenolics were negatively related to leaf N in both groups but only negatively related to leaf P for architectural defenders. Our results suggest that architectural defenders are less able to accumulate phenolic defences in high P soils than non-architectural defender. One possible explanation is that phenolic production is limited in P-rich soils via active phloem loading, but only in architectural defenders that have defence options other than chemical ones.

Aim Plant herbivory and disease, which are often associated with each other but subject to different processes, are pivotal in biodiversity maintenance and ecosystem function. Although drivers of plant herbivory and disease have been widely studied separately, their relationships, patterns and determinants remain unclear in fragmented landscapes. Methods We surveyed incidence and severity of foliar herbivory and disease of 2,027 adult trees within 30 sites in 17 tropical forest fragments in Xishuangbanna, southwestern China. We aim to explore the relationship of plant herbivory and disease, and effects of local environmental variables (forest type, plant richness, elevation, slope, soil properties) and landscape environmental variables (patch size, edge distance, isolation). Results We found that incidence, but not severity of disease was positively correlated with that of herbivory. Herbivory severity and incidence were more associated with local variables; both increased with plant richness but decreased with soil nutrients and pH. In contrast, the landscape variable isolation was the dominant driver of disease, with lower severity and incidence in contiguous forests than forest fragments. Conclusion In summary, we show that herbivory and disease are associated with drivers at different scales in fragmented landscapes. Herbivory is mainly driven by local-scale variables, while disease is mainly driven by landscape-scale variables. To control plant herbivory and disease in fragmented landscapes, increasing landscape connectivity and conserving different forest types are urgently required to maintain ecosystem functions under global land use change.

The role of trait variability in mediating plant community responses to environmental change remains poorly resolved. We conducted a 5-year study across 45 fragments in a tropical dry forest to understand shifts in trait means and variabilities of the trees classified into two functional types, drought avoiders and drought tolerators, across a soil moisture gradient, and their association with changes in site-level productivity. Trait means changed in opposite directions across the soil moisture gradient for the two functional types, especially for water safety and leaf carbon capture traits. Trait variabilities were generally greater at dry sites for drought avoiders and at wet sites for drought tolerators. Site-level growth rates were related to different sets of trait means and variabilities for the two functional types. Projected changes in precipitation will likely shift the vegetation to greater representation of drought tolerators and will be accompanied by non-linear increases in standing biomass.