Dry and low nutrient conditions shift conspecific interactions from negative to positive, and responses depend on trait.

Cocoa agroforestry systems (AFS) provide multiple ecosystem services, which are influenced by features of the shade tree community. By strategically selecting and managing shade trees based on their functional traits, cocoa farmers can affect functional diversity of AFS and potentially enhance the benefits they deliver. In this research, we applied functional trait ecology to better understand the effect of functional diversity of cocoa AFS on three ecosystem services: carbon storage, soil fertility, and provisioning of cocoa and other products. To achieve this, we characterized 30 AFS across a gradient of ecological complexity and established relationships between functional diversityw indices and ecosystem services using ANOVA and multiple regression models. As a result, two contrasting ecological dynamics were observed: low-complexity AFS, dominated by resource-conservative traits (higher leaf dry matter content, higher stem specific density, and low leaf nitrogen concentration), were associated with lower carbon stocks and soil fertility, while high-complexity AFS, characterized by resource-acquisitive traits (low leaf dry matter content, low stem specific density, and high leaf nitrogen concentration), delivered greater ecosystem services. Through the multiple regression analysis, we found that AFS dominated by species with greater maximum potential height, greater leaf nitrogen concentration, lower leaf dry matter content, lower leaf mass per area, and lower leaf nitrogen-phosphorus ratio were associated with higher carbon storage (R2 = 0.84), soil fertility (R2 = 0.7 for soil nitrogen), and multiple ecosystem services (R2 = 0.78). Additionally, cocoa yields were negatively correlated with shade cover and the dominance of large-leaf shade trees, revealing a potential trade-off between maximizing yields and enhancing ecosystem services. Nevertheless, the models indicated that a win-win scenario can be achieved when shade trees are productive, generating additional benefits. Finally, our study highlights critical relationships between shade tree traits and delivery of key ecosystem services for farm sustainability and farmer livelihoods.

Invasive alien plant effects on ecosystem functions are often difficult to predict across environmental gradients due to the context‐dependent interactions between the invader and the recipient communities. Adopting a functional trait‐based framework could provide more mechanistic predictions for invasive species' impacts. In this study, we contrast litter decomposition rates among communities with and without the invasive plant Impatiens glandulifera in five regions along a 1600 km long latitudinal gradient in Europe. Across this gradient, four functional traits, namely leaf dry matter content (LDMC), specific leaf area (SLA), stem‐specific density (SSD), and plant height, are correlated to rates of litter decomposition of standardized rooibos (labile), green tea (recalcitrant), and I. glandulifera litter. Our results show that both invaded and non‐invaded plant communities had a higher expression of acquisitive traits (low LDMC and SSD, high SLA) with increasing temperature along the latitudinal gradient, partly explaining the variation in decomposition rates along the gradient. At the same time, invasion shifted community trait composition toward more acquisitive traits across the latitudinal gradient. These trait changes partly explained the increased litter decomposition rates of the labile litter fraction of rooibos and I. glandulifera litter in invaded communities, a shift that was most evident in the warmer study regions. Plant available nitrogen was lower in invaded communities, likely due to high nutrient uptake by I. glandulifera. Meanwhile, the coldest study region was characterized by a reversed effect of invasion on decomposition rates. Here, community traits related to low litter quality and potential allelopathic effects of the invader resulted in reduced litter decomposition rates, suggesting a threshold temperature at which invader effects on litter decomposition turn positive. This study therefore illustrates how functional trait changes toward acquisitive traits can help explain invader‐induced changes in ecosystem functions such as increased litter decomposition.

Forage selection by herbivores is a major driver of plant diversity in pasture vegetation. Yet, we know relatively little about how plant traits influence decisions of different herbivore species and breeds to select or avoid a certain plant species on semi‐natural pastures. We quantified the influence of the traits leaf N and P content, leaf dry matter content (LDMC), specific leaf area (SLA) and physical defence mechanisms on plant species selection for three cattle breeds: high‐yielding Angus × Holstein crossbreed, dual‐purpose Original Braunvieh and undemanding Highland Cattle. The cattle grazed a series of adjacent paddocks in different alpine pastures. Plant species selection was quantified by assessing the difference in biomass proportions of all plant species in 66 vegetation subplots per breed before and after grazing. Plant traits and indicator values were extracted from the TRY database. Data on 152 plant species were analysed using a local mixed‐effects model and a global multivariate hierarchical regression model. Plant traits had a clear impact on forage behaviour. Plants with high SLA, leaf N and P contents were significantly selected, whereas plants with high LDMC (e.g. woody plants) and defence mechanisms (e.g. thistles) were generally avoided. Species with high forage quality indicator values as defined by Briemle et al. (2002) were significantly preferred. More importantly, significant differences between forage behaviour of cattle breeds were detected. Selection by less‐productive Highland Cattle was much less influenced by plant traits than the selection by the two higher‐yielding breeds. Results indicate a clear impact of plant traits on forage selection and demonstrate breed‐specific influences. Highland Cattle (and possibly other robust breeds) graze less selectively and impose less selective exclusion on plants. Thereby, they likely influence plant species composition of pastures in a different way than high‐yielding breeds, thereby creating a distinct habitat. A free Plain Language Summary can be found within the Supporting Information of this article.

When seeds fallen from the mother trees, their initial contact physical environment was litter or soil. The dispersal positions of seeds (seeds positioned on top of the litter, the soil surface and beneath the litter) determine the process of their natural regeneration. We simulated three different dispersal positions of Castanopsis kawakamii, including seeds positioned on top of the litter (2 and 4 cm litter was placed below the seed layer), soil surface (without litter), and seeds beneath the litter (2, 4, 6 and 8 cm litter covers in the upper layer of seeds). We examined the effects of seed dispersal position on the chlorophyll fluorescence characteristics, non-structural carbohydrate, specific leaf area, leaf dry matter content and nutrient content of seedlings. The results showed that leaf nitrogen content per area of seedlings had significantly positive correlation with soluble sugar content, non-structural carbohydrate content, and negative correlation with specific leaf area across different dispersal positions. Seedlings of the moderate litter cover (2 and 4 cm) adopted resource acquisitive strategies by increasing relative chlorophyll content, soluble sugar content, non-structural carbohydrate content, leaf dry matter content, leaf nitrogen content and phosphorus contents per area, and decreasing specific leaf area to achieve their demands for rapid growth. Seedlings grew on soil surface and beneath the deep litter (6 and 8 cm) adopted the resource conservative strategies with higher leaf nitrogen content per mass and specific leaf area, lower leaf dry matter content, and non-structural carbohydrate content to intercept more effective light resources to compensate for the shady environment brought by deep litter. This would further decrease the probability of seedling mortality due to 'carbon starvation'. Seedlings under litter layer stored starch in leaf, and reduced the energy consumption of photosynthetic tissues (low PSⅡ maximum photochemical efficiency) to maintain seedling growth. Comprehensive analysis of entropy method indicated that low amount of litter cover (2 cm) significantly promoted seedling growth of C. kawakamii. In the future, we could regulate the thickness of litter layer to promote the growth and regeneration of C. kawakamii seedlings in natural forest.

Climate change is one of the main challenges facing humanity in the coming century. To understand the impact of climate change on biodiversity and ecosystem functioning, we urgently require a better understanding of plant responses to climate change. To address this knowledge gap we established a full-factorial warming experiment using open-top chambers (OTCs) inside a long-term fire-manipulation experiment in Afromontane fire-climax grasslands. Fire is an essential ecosystem driver in these grasslands, but has rarely been included in experimental climate change research. To assess growth responses to elevated temperatures and fire frequency, we measured four functional traits: vegetative height, leaf area (LA), specific leaf area (SLA), and leaf dry matter content (LDMC). Grasses responded to fire exclusion with increased height, and lower LA, SLA, and LDMC. Grasses responded to warming with lower height and LA, and higher LDMC, suggesting that plant growth was negatively affected by warming. This response was mostly attributed to intra-specific trait variability, highlighting an important role for trait plasticity in community-level processes to mediate the response of montane grassland communities to elevated temperatures and associated drought effects. These results are a first step towards establishing a more mechanistic basis for understanding future climatic changes in Afromontane grasslands.

Summary Plant–soil feedback (PSF), plant trait and functional group concepts advanced our understanding of plant community dynamics, but how they are interlinked is poorly known. To test how plant functional groups (FGs: graminoids, small herbs, tall herbs, legumes) and plant traits relate to PSF, we grew 48 grassland species in sterilized soil, sterilized soil with own species soil inoculum and sterilized soil with soil inoculum from all species, and quantified relative growth rate (RGR), specific leaf area (SLA), specific root length (SRL) and per cent arbuscular mycorrhizal fungi colonization (%AMF). Plant growth response to the plant species' own soil biota relative to sterilized soil (PSFsterilized) reflects net effects of all (generalist + specialized) soil biota. Growth response to the plant species' own soil biota relative to soil biota of all plant species (PSFaway) reveals effects of more specialized soil organisms. PSFsterilized showed that graminoids and small herbs have a negative and tall herbs a positive response to their own soil biota, whereas legumes responded neutrally. However, PSFaway showed that on average, all plant FGs benefitted from growing with other species' soil biota, suggesting that pathogens are more specialized than plant growth‐promoting soil biota. Feedback to plant growth from all soil biota (PSFsterilized) was stronger than from more specialized soil biota (PSFaway) and could be predicted by SRL and especially by %AMF colonization. Species with high SRL and low %AMF colonization when grown in away soil experienced most negative soil feedback. Synthesis. Plant species from all plant FGs grow better in soil from other species because of less net negative effects of soil biota (in graminoids), or because of more net positive soil biota effects (in tall herbs). Explorative plant species (high SRL, low %AMF colonization) suffer most from negative feedback of all soil biota, whereas more resource conservative species (low SRL, high %AMF colonization) benefit from soil feedback of all soil biota. These findings help to understand replacement of explorative species during succession. Moreover, we suggest a potentially larger role for species with positive feedback than for species with negative feedback to contribute to maintain plant community productivity of diverse communities over time.

ABSTRACTFagus hayatae Palib. ex Hayata, an endangered East Asian paleoendemic species, dominates in Sichuan's Micang Mountain while persisting in fragmented populations across Taiwan and mainland China. Nevertheless, niche differentiation and adaptive strategies between this species and its close congener (F. engleriana) remain poorly understood. Leaf functional traits—key indicators of plant resource‐use strategies—reveal ecological adaptations through their interrelationships and environmental responses. Here, we examined interspecific variation in leaf functional traits among F. hayatae, F. engleriana, and co‐dominant tree species, and analyzed the trait variation in F. hayatae with respect to elevation to elucidate climate adaptation mechanisms (Micang Mountain Nature Reserve, China). F. hayatae and F. engleriana exhibited low niche overlap as community dominants. Compared to associated dominants, F. hayatae displayed higher leaf dry matter content (LDMC), specific leaf area (SLA), leaf carbon content (LCC), and leaf phosphorus content (LPC), alongside smaller stomata with lower density. Conversely, F. engleriana manifested stronger resource‐acquisition traits: larger leaf width (LW), leaf area (LA), SLA, LCC, higher leaf nitrogen content (LNC), and greater stomatal density, yet lower LPC. Direct comparison revealed that F. hayatae possesses larger but sparser stomata and reduced resource‐acquisition capacity relative to F. engleriana, evidenced by lower LL, LW, LA, SLA, LCC, and LNC. Elevation significantly modulated F. hayatae's leaf traits. At lower elevations, increased LA and SLA indicated acquisitive tendencies, whereas higher elevations favored conservative strategies: reduced LA, SLA, stomatal area (SA), and LPC. This underscores F. hayatae's superior phenotypic plasticity and reliance on defense‐oriented adaptations compared to sympatric F. engleriana. Critically, mid‐elevations supported optimal performance via coordinated stress‐tolerance traits. These findings highlight the priority of protecting mid‐elevation habitats where F. hayatae achieves peak fitness, and the need for proactive habitat preservation due to its conservative strategy, which entails slower post‐disturbance recovery.

Leaf photosynthetic and functional traits of dominant species are important for understanding grassland community dynamics under imbalanced nitrogen (N) and phosphorus (P) inputs. Here, the effects of N (N0, N50, and N100, corresponding to 0, 50, and 100 kg ha−1 yr−1, respectively) or/and P additions (P0, P40, and P80, corresponding to 0, 40, and 80 kg ha–1 yr–1) on photosynthetic characteristics and leaf economic traits of three dominant species (two grasses: Bothriochloa ischaemum and Stipa bungeana; a leguminous subshrub: Lespedeza davurica) were investigated in a semiarid grassland community on the Loess Plateau of China. Results showed that, after a three-year N addition, all three species had higher specific leaf area (SLA), leaf chlorophyll content (SPAD value), maximum net photosynthetic rate (PNmax), and leaf instantaneous water use efficiency (WUE), while also having a lower leaf dry matter content (LDMC). The two grasses, B. ischaemum and S. bungeana, showed greater increases in PNmax and SLA than the subshrub L. davurica. P addition alone had no noticeable effect on the PNmax of the two grasses while it significantly increased the PNmax of L. davurica. There was an evident synergetic effect of the addition of N and P combined on photosynthetic traits and most leaf economic traits in the three species. All species had relatively high PNmax and SLA under the addition of N50 combined with P40. Overall, this study suggests that N and P addition shifted leaf economic traits towards a greater light harvesting ability and, thus, elevated photosynthesis in the three dominant species of a semiarid grassland community, and this was achieved by species–specific responses in leaf functional traits. These results may provide insights into grassland restoration and the assessment of community development in the context of atmospheric N deposition and intensive agricultural fertilization.

The growth strategies of plant species show the ecological role which is reflexed by their adaptation to environments and competitiveness. Those are essential in the study of the revegetation effectiveness. However, the growth strategies of plant species in various types of habitats have not yet been fully investigated. The objective of this study was to investigate the growth strategies of ten woody plant species which were naturalized from mangrove to lowland habitats in relation to their effectiveness for revegetation program. The seedling’s growth was recorded during 4 months in Purwodadi Botanic Garden-LIPI from October 2014 to February 2015. Complete randomized design with plant species as a treatment using 3 replications was carried out to examine the plant’s Relative Growth Rates (RGRs), their components, leaf nitrogen productivity and growth strategies.The study showed that RGRs of ten woody plants species varied across species. Based on the Pearson correlations, the plant’s Net Assimilation Rates (NAR) and two ecological traits related to the root trait i.e. Nitrogen productivity and Specific Root Length (SRL) were strongly correlated with the RGRs. Heritiera littoralis, Diospyros discolor, Antidesma bunius, Schleichera oleosa, Madhuca longifolia and Syzygium cumini have high RGRs but low Specific Leaf Area (SLA). B. asiatica has relatively low RGRs and SLA, while Dracontomelon dao have high RGRs and SLA. It showed that most of plant species studied, except D. dao achieve growth rates and competitiveness by developing strategies through forming fine roots to maximize its ecological function in nutrients uptake. Most of woody plant species are adaptive to dry lowland habitat and only D. dao potentially occupy the ecosystem. Furthermore, D. discolor and S. oleosa are highly recommended for revegetation in degraded tropical lowland areas.

Little research has been done on the nutritive value of species‐rich permanent grasslands in spite of their recognized ecological value. We proposed a new method based on the concept of plant functional type (PFT) to rank grass species and grasslands according to the organic matter digestibility (OMD) of the plant material. The PFTs are based on leaf dry matter content (LDMC). The objectives of this study were: (i) to see if there were significant differences between PFTs for the three components of plant OMD (leaf and stem digestibility and leaf proportion [L%]) in a set of 19 grasses growing in pure stand under two contrasting levels of N supply (Exp. 1); (ii) to see whether grassland vegetation types (GVT) differing in their PFT composition have different digestibility values; investigations being made on the leaf, stem, and whole plant OMD of five and eight plant communities (Exp. 2 and 3, respectively). In pure grass stands (Exp. 1) as well as in grassland communities (Exp. 2 and 3), there was a significant effect of PFT or GVT on leaf and stem OMD. The greatest differences in L% were observed when there were large differences in nutrient availability. At the leafy stage, the whole plant digestibility was higher for GVTs composed of PFTs with a low LDMC. However around the time of flowering there was a convergence in whole‐plant OMD between all grassland communities because L% decreased faster for those composed of PFTs having the lowest LDMC. At this stage, plots with low LDMC had higher plant component digestibility but lower L%. Our results show that the decrease in plant digestibility over time is the result of two processes, an ontogenic one, due to a decrease in leaf proportion, and an ageing one. For the latter, we show that PFT had an effect of leaf and stem digestibility at an early stage of plant development, then they decreased at a rate depending on plant development. Both processes explained the convergence between GVTs in plant digestibility at flowering time.

Phenotypic plasticity of water-related traits reveals boundaries to the adaptive capacity of a dominant European grass species under increased drought

Summary Root, stem and leaf traits are thought to be functionally coordinated to maximize the efficiency of acquiring and using limited resources. However, evidence is mixed for consistent whole‐plant trait coordination among woody plants, and we lack a clear understanding of the adaptive value of root traits along soil resource gradients. If fine roots are the below‐ground analogue to leaves, then low specific root length (SRL) and high tissue density should be common on infertile soil. Here, we test the prediction that root, stem and leaf traits and relative growth rate respond in unison with soil fertility gradients. We measured fine root, stem and leaf traits and relative growth rate on individual seedlings of 66 tree species grown in controlled conditions. Our objectives were (i) to determine whether multiple root traits align with growth rate, leaf and stem traits and with each other and (ii) to quantify the relationships between community‐weighted mean root traits and two strong soil fertility gradients that differed in spatial extent and community composition. At the species level, fast growth rates were associated with low root and stem tissue density and high specific leaf area. SRL and root diameter were not clearly related to growth rate and loaded on a separate principal component from the plant economic spectrum. At the community level, growth rate was positively related to soil fertility, and root tissue density (RTD) and branching were negatively related to soil fertility. SRL was negatively related and root diameter was positively related to soil fertility on the large‐scale gradient that included ectomycorrhizal angiosperms. Synthesis. Root, stem and leaf tissue traits of tree seedlings are coordinated and influence fitness along soil fertility gradients. RTD responds in unison with above‐ground traits to soil fertility gradients; however, root traits are multidimensional because SRL is orthogonal to the plant economic spectrum. In contrast to leaves, trees are not constrained in the way they construct fine roots: plants can construct high or low SRL roots of any tissue density. High RTD is the most consistent below‐ground trait that reflects adaptation to infertile soil.

Natural selection is the major force driving adaptive evolution in natural populations, varying in strength, direction, and form through space and time, especially in highly variable environments such as Mediterranean ecosystems. Although a conservative resource‐use strategy has been hypothesized to be adaptive in Mediterranean taxa, patterns of selection at the intraspecific level, that is, the suite of traits determining individual fitness, are largely unknown.Using a phenotypic selection experiment in natural semi‐arid conditions, we measured direct and indirect selection acting through two different fitness components (survival and reproduction), to assess the adaptive value of 20 ecophysiological traits on individuals of two gypsum endemic species,Centaurea hyssopifoliaandHelianthemum squamatum, dwelling in environments with contrasting abiotic conditions (south‐ and north‐facing slopes) during two climatically contrasting years (dry and mesic). This allowed quantifying the magnitude and direction of natural selection at different spatiotemporal scales.Our results revealed that different abiotic conditions did not alter selection patterns, being the magnitude of selection more strongly affected by temporal environmental variation. Selection through reproduction indicated consistent selection for early phenology, low water use efficiency, high specific leaf area, low leaf dry matter content, and high leaf N across slopes and years in both species. In contrast, phenotypic trait variation was not linked to survival in either species. Furthermore, while individual reproductive output was higher or similar in environments with higher abiotic stress in both species and years, survival was similar across environmental conditions, and it was neither affected by plant size nor reproductive output.Contrary to our expectations, natural selection via reproductive fitness consistently favoured a drought‐escape, acquisitive resource‐use strategy in Mediterranean semi‐arid plants, rather than a conservative resource‐use strategy, even under conditions of higher abiotic stress (i.e. south slopes and dry year). Such acquisitive strategy could allow rapid development by maximizing resource assimilation and reproduction before the most limiting climatic conditions of mid‐late summer. Our results shed light on adaptive functional strategies of Mediterranean taxa at the intraspecific level, providing insight on future responses to environmental change, and highlight remarkable differences in selection acting through different fitness components.Read the freePlain Language Summaryfor this article on the Journal blog.

A comprehensive understanding of the effects of mountain roads on plant diversity is critical to finding the most effective solutions for managing this particular driver. Little is known, however, about the simultaneous effects that road have on the multiple facets of biodiversity, although roads are considered to be one of the major disturbances in the Qionglai mountain range. In this study, we analyzed the impact of roads on the multiple facets of plant diversity (taxonomic, functional and phylogenetic diversity) in the study area using Hill numbers by comparing plant diversity between roadside and interior plots at the landscape scale, then, we used linear mixed models to analyze the effect of mountain roads on the multiple facets of plant diversity along an elevational gradient. The results showed that the roadside plots lacked 29.45% of the total number of species with particular functional traits (such as a relatively high specific leaf area (SLA), a relatively low leaf dry matter content (LDMC) and relatively old clades) and exclusively contained 14.62% of the total number of species. Compared with the interior community, the taxonomic, functional and phylogenetic diversity of roadside community decreased by no more than 26.78%, 24.90% and 16.62%, respectively. Taxonomic and functional diversity of dominant and common species showed greater changes to road disturbances, while rare species showed the greatest change in phylogenetic diversity. Taxonomic homogenization of roadside communities was accompanied by functional and phylogenetic homogenization. Additionally, the impact of roads on these three facets of plant diversity showed the characteristics of peak clipping along the elevation gradient. Our findings highlight the negative impact of roads on the taxonomic, functional and phylogenetic diversity of the Qionglai mountain range, as roads promote communities that are more similar in taxonomic, functional, and phylogenetic composition, and to a greater extent contributed to compositional evenness. These effects tend to be functionally and phylogenetically non-random, and species in some clades or with some functional traits are at higher risk of loss. Our results are important for the conservation and management of nature reserves, especially for local governments aiming to create new infrastructure to connect natural mountainous areas.

The path followed by species in the colonization of remote oceanic islands ultimately depends on their phylogenetic constraints and ecological responses. In this study, we aim to evaluate the relative role of geographical and ecological forces in the origin and evolution of the Madeiran ivy (Hedera maderensis), a single-species endemic belonging to the western polyploid clade of Hedera. To determine the phylogenetic placement of H. maderensis within the western polyploid clade, we analyzed 40 populations (92 individuals) using genotyping-by-sequencing and including Hedera helix as outgroup. Climatic niche differences among the study species were evaluated using a database with 867 records representing the entire species ranges. To test species responses to climate, 13 vegetative and reproductive functional traits were examined for 70 populations (335 individuals). Phylogenomic results revealed a nested pattern with H. maderensis embedded within the south-western Iberian H. iberica. Gradual niche differentiation from the coldest and most continental populations of H. iberica to the warm and stable coastal population sister to H. maderensis parallels the geographical pattern observed in the phylogeny. Similarity in functional traits is observed for H. maderensis and H. iberica. The two species show leaves with higher specific leaf area (SLA), lower leaf dry matter content (LDMC) and thickness and fruits with lower pulp fraction than the other western polyploid species H. hibernica. Acquisition of a Macaronesian climatic niche and the associated functional syndrome in mainland European ivies (leaves with high SLA, and low LDMC and thickness, and fruits with less pulp content) was a key step in the colonization of Madeira by the H. iberica/H. maderensis lineage, which points to climatic pre-adaptation as key in the success of island colonization (dispersal and establishment). Once in Madeira, budding speciation was driven by geographical isolation, while ecological processes are regarded as secondary forces with a putative impact in the lack of further in situ diversification.