Diversity-productivity Relationships Research Articles

The functional diversity-productivity relationship of woody plants is climatically sensitive.

Plot-scale experiments indicate that functional diversity (FD) plays a pivotal role in sustaining ecosystem functions such as net primary productivity (NPP). However, the relationships between functional diversity and NPP across larger scale under varying climatic conditions are sparsely studied, despite its significance for understanding forest-atmosphere interactions and informing policy development. Hence, we examine the relationships of community-weighted mean (CWM) and functional dispersion (FDis) of woody plant traits on NPP across China and if such relationships are modulated by climatic conditions at the national scale. Using comprehensive datasets of distribution, functional traits, and productivity for 9120 Chinese woody plant species, we evaluated the distribution pattern of community-weighted mean and functional dispersion (including three orthogonal trait indicators: plant size, leaf morphology, and flower duration) and its relationships with NPP. Finally, we tested the effects of climatic conditions on community-weighted mean/functional dispersion-NPP relationships. We first found overall functional diversity-NPP relationships, but also that the magnitude of these relationships was sensitive to climate, with plant size community-weighted mean promoting NPP in warm regions and plant size functional dispersion promoting NPP in wet regions. Second, warm and wet conditions indirectly increased NPP by its positive effects on community-weighted mean or functional dispersion, particularly through mean plant size and leaf morphology. Our study provides comprehensive evidence for the relationships between functional diversity and NPP under varying climates at a large scale. Importantly, our results indicate a broadening significance of multidimensional plant functional traits for woody vegetation NPP in response to rising temperatures and wetter climates. Restoration, reforestation actions and natural capital accounting need to carefully consider not only community-weighted mean and functional dispersion but also their interactions with climate, to predict how functional diversity may promote ecosystem functioning under future climatic conditions.

Cross-domain diversity effects: linking diatom species richness, intraspecific richness, and biomass production to host-associated bacterial diversity

Abstract Interactions between bacteria and microalgae are important for the functioning of aquatic ecosystems, yet interactions based on the biodiversity of these two taxonomic domains have been scarcely studied. Specifically, it is unclear whether a positive biodiversity-productivity relationship in phytoplankton is largely facilitated by niche partitioning among the phytoplankton organisms themselves, or whether associated bacterial communities play an additional role in modifying these diversity effects. Moreover, effects of intraspecific diversity in phytoplankton communities on bacterial community diversity have not been tested. To address these points, we factorially manipulated both species and intraspecific richness of three diatoms to test effects of diatom species/strain diversity on biomass production and bacterial diversity in algae-bacteria communities. The results show that diatom intraspecific diversity has significant positive effects on culture biomass and the diversity of the associated free-living bacterial community (0.2-3 μm size fraction), which are comparable in magnitude to species diversity effects. However, there were little to no effects of diatom diversity on host-associated bacterial diversity (>3 μm size fraction), or of bacterial diversity on biomass production. These results suggest a decoupling of bacterial diversity from the diatom diversity-productivity relationship and provide early insights regarding the relations between diversity across domains in aquatic ecosystems.

Nitrogen Addition and Heterotroph Exclusion Affected Plant Species Diversity-Biomass Relationship by Affecting Plant Functional Traits.

(1) Background: Heterotrophs can affect plant biomass and alter species diversity-productivity relationships. However, these studies were conducted in systems with a low nitrogen (N) availability, and it is unclear how heterotroph removal affects the relationship between plant species diversity and productivity in different N habitats. (2) Methods: Three typical understory herbaceous plants were selected to assemble the plant species diversity (three plant species richness levels (1, 2, and 3) and seven plant species compositions), and the control, insecticide, fungicide, and all removal treatments were performed at each plant species diversity level in systems with or without N addition treatments. (3) Results: In systems without N addition, the insecticide treatment increased the plant aboveground biomass, total biomass, and leaf area, while the fungicide treatment reduced the plant belowground biomass, root length, and root tip number; the presence of Bidens pilosa increased the plant aboveground biomass. Similarly, the presence of Bletilla striata increased the plant belowground biomass and root diameter under each heterotroph removal treatment. In systems with N addition, all removal treatments reduced the plant belowground biomass and increased the plant leaf area; the presence of B. pilosa significantly increased the plant aboveground biomass, total biomass, and root length under each heterotroph removal treatment. The presence of B. striata significantly increased the plant belowground biomass and leaf area under insecticide and fungicide treatments. (4) Conclusions: Heterotroph removal alters the plant species diversity-biomass relationship by affecting the plant functional traits in systems with different N availabilities. The impact of biodiversity at different trophic levels on ecosystem functioning should be considered under the background of global change.

Land use intensity controls the diversity-productivity relationship in northern temperate grasslands of China.

The diversity-productivity relationship is a central issue in maintaining the grassland ecosystem's multifunctionality and supporting its sustainable management. Currently, the mainstream opinion on the diversity-productivity relationship recognizes that increases in species diversity promote ecosystem productivity. Here, we challenge this opinion by developing a generalized additive model-based framework to quantify the response rate of grassland productivity to plant species diversity using vegetation survey data we collected along a land-use intensity gradient in northern China. Our results show that the grassland aboveground biomass responds significantly positively to the Shannon-Wiener diversity index at a rate of 46.8 g m-2 per unit increase of the Shannon-Wiener index in enclosure-managed grasslands, under the co-influence of climate and landscape factors. The aboveground biomass response rate stays positive at a magnitude of 47.1 g m-2 in forest understory grassland and 39.7 g m-2 in wetland grassland. Conversely, the response rate turns negative in heavily grazed grasslands at -55.8 g m-2, transiting via near-neutral rates of -7.0 and -7.3 g m-2 in mowing grassland and moderately grazed grassland, respectively. These results suggest that the diversity-productivity relationship in temperate grasslands not only varies by magnitude but also switches directions under varying levels of land use intensity. This highlights the need to consider land use intensity as a more important ecological integrity indicator for future ecological conservation programs in temperate grasslands.

Systematic distributions of interaction strengths across tree interaction networks yield positive diversity-productivity relationships.

Understanding the mechanisms underlying diversity-productivity relationships (DPRs) is crucial to mitigating the effects of forest biodiversity loss. Tree-tree interactions in diverse communities are fundamental in driving growth rates, potentially shaping the emergent DPRs, yet remain poorly explored. Here, using data from a large-scale forest biodiversity experiment in subtropical China, we demonstrated that changes in individual tree productivity were driven by species-specific pairwise interactions, with higher positive net pairwise interaction effects on trees in more diverse neighbourhoods. By perturbing the interactions strength from empirical data in simulations, we revealed that the positive differences between inter- and intra-specific interactions were the critical determinant for the emergence of positive DPRs. Surprisingly, the condition for positive DPRs corresponded to the condition for coexistence. Our results thus provide a novel insight into how pairwise tree interactions regulate DPRs, with implications for identifying the tree mixtures with maximized productivity to guide forest restoration and reforestation efforts.

Tree and shrub richness modifies subtropical tree productivity by regulating the diversity and community composition of soil bacteria and archaea

BackgroundDeclines in plant biodiversity often have negative consequences for plant community productivity, and it becomes increasingly acknowledged that this may be driven by shifts in soil microbial communities. So far, the role of fungal communities in driving tree diversity-productivity relationships has been well assessed in forests. However, the role of bacteria and archaea, which are also highly abundant in forest soils and perform pivotal ecosystem functions, has been less investigated in this context. Here, we investigated how tree and shrub richness affects stand-level tree productivity by regulating bacterial and archaeal community diversity and composition. We used a landscape-scale, subtropical tree biodiversity experiment (BEF-China) where tree (1, 2, or 4 species) and shrub richness (0, 2, 4, 8 species) were modified.ResultsOur findings indicated a noteworthy decline in soil bacterial α-diversity as tree species richness increased from monoculture to 2- and 4- tree species mixtures, but a significant increase in archaeal α-diversity. Additionally, we observed that the impact of shrub species richness on microbial α-diversity was largely dependent on the level of tree species richness. The increase in tree species richness greatly reduced the variability in bacterial community composition and the complexity of co-occurrence network, but this effect was marginal for archaea. Both tree and shrub species richness increased the stand-level tree productivity by regulating the diversity and composition of bacterial community and archaeal diversity, with the effects being mediated via increases in soil C:N ratios.ConclusionsOur findings provide insight into the importance of bacterial and archaeal communities in driving the relationship between plant diversity and productivity in subtropical forests and highlight the necessity for a better understanding of prokaryotic communities in forest soils.-4HQdD_EuWHa-cff1NJXs2Video

A linear positive relationship between tree species diversity and forest productivity across forest-dominated natural reserves on a large spatial scale

Exploring diversity-productivity relationships (DPRs) of various ecosystems is essential to forest management and conservation, as it can inform us about the dynamics and future trend of forest productivity and carbon sequestration under the change of species diversity. However, the DPR of natural reserve and its formation mechanisms are poorly understood, although such ecosystem plays a key role in protecting species diversity and maintaining carbon sink and other ecological service functions. By integrating ground survey data of 113,007 trees of 163 tree species from 1029 plots and remotely sensed vegetation data, we investigated the DPR features as well as the mechanisms behind them of 25 forest-dominated national natural reserves across the large part of northeastern China. We found a significant (P < 0.01) positive relationship between species diversity index and aboveground biomass across the analyzed natural reserves on a large spatial scale. In addition, the species diversity index and aboveground biomass obtained from the ground survey data were significantly (P < 0.01) and positively correlated with satellite-derived enhanced vegetation index linked to forest productivity, further confirming the robustness of the linear positive DPR observed. These results indicate that forest productivity and carbon sequestration would probably decline if a decrease in tree species number, highlighting the importance of species diversity protection in natural reserves. A structural equation modeling analysis suggested that heat-related and water-related climate factors played predominant roles in modulating species diversity index and aboveground biomass respectively and hence DPR across the natural reserves studied. Meanwhile, geographical location (i.e. latitude and longitude) can indirectly affect DPR by regulating the climate factors above. The findings of this study can contribute to understanding the DPR and predicting the future trends of forest carbon sink under climate change and thus to sustainable forest management for our study region as well as other similar natural reserves.

Animal and plant space-use drive plant diversity-productivity relationships.

Plant community productivity generally increases with biodiversity, but the strength of this relationship exhibits strong empirical variation. In meta-food-web simulations, we addressed if the spatial overlap in plants' resource access and animal space-use can explain such variability. We found that spatial overlap of plant resource access is a prerequisite for positive diversity-productivity relationships, but causes exploitative competition that can lead to competitive exclusion. Space-use of herbivores causes apparent competition among plants, resulting in negative relationships. However, space-use of larger top predators integrates sub-food webs composed of smaller species, offsetting the negative effects of exploitative and apparent competition and leading to strongly positive diversity-productivity relationships. Overall, our results show that spatial overlap of plants' resource access and animal space-use can greatly alter the strength and sign of such relationships. In particular, the scaling of animal space-use effects opens new perspectives for linking landscape processes without effects on biodiversity to productivity patterns.

More effect of ephemeral plant species diversity on aboveground biomass than functional diversity and functional composition

AbstractThe quantification of plant diversity–productivity relationships is essential for accurate productivity assessments. Global change drivers are altering resource availability and biodiversity. However, the extent to which multiple attributes of diversity (species, functions) buffer community productivity in response to the resource availability changes and the potential driver mechanisms of the diversity‐productivity relationship still needs to be the consensus. We investigated the ephemeral plant diversity–productivity relationships of different attributes along a precipitation gradient in the Gurbantunggut Desert, China. To evaluate the potential mechanisms by which diversity and functional composition affect aboveground productivity (niche complementarity and selection effect). Our results showed that (1) the variance of species richness (SR), Rao's quadratic entropy (RaoQ), community‐weighted mean of height (CWMH), and community‐weighted mean of leaf phosphorus concentration (CWMP) was larger among sites (variation between different sites) than subplots (variation between different subplots). Among subplots, the variance of community‐weighted mean of specific leaf area (CWMSLA), community‐weighted mean of leaf carbon concentration (CWMC), and community‐weighted mean of leaf nitrogen concentration (CWMN) was larger than the sites. (2) SR, RaoQ, CWMC, CWMN, CWMH, pH, and mean annual precipitation (MAP) collectively influenced the accumulation of aboveground biomass (AGB). (3) Species diversity and MAP have strongly affected AGB and accounted for 50% and 42%. The study confirms that SR is the optimal predictor of biomass in ephemeral plants. Complementation effects may be the primary mechanism explaining the relationship between biodiversity and productivity in the Gurbantunggut Desert, and thus the effect of plant diversity cannot be downplayed.

Soil fungal communities contribute to the positive diversity–productivity relationship of tree communities under contrasting water availability

Abstract Plant diversity has often been linked to increased productivity; however, this apparent diversity–productivity relationship may rely on intertrophic interactions such as those between plants and soil microbes. Soil fungi can create complementarity between plant species via altered plant resource partitioning, facilitation via fungal networks or biotic feedbacks, thereby promoting plant diversity–productivity relationships. Furthermore, these relationships are likely to be context dependent in response to resource availability. We used a biodiversity–ecosystem function experiment with trees exposed to high and low water availability treatments to determine the contribution of soil fungal communities to the diversity–productivity relationship in tree communities. We used amplicon sequencing of soil fungi to assess fungal richness, community composition and richness of functional guilds. We then applied structural equation modelling to determine relationships between tree diversity, fungal communities and tree productivity and the role of water availability in these relationships. Tree species richness and functional diversity both increased above‐ground tree productivity and influenced soil fungal community composition. Fungal community composition had a direct impact on tree productivity and enhanced net diversity effects on productivity. Therefore, fungal communities mediated a positive, indirect effect of tree richness on productivity. While total fungal richness was not associated with tree diversity, pathogen richness decreased and mycorrhizal richness increased with tree richness. Pathogen and mycorrhizal richness had either no impact or a weak negative effect on productivity. Tree species traits strongly affected fungal communities and these changes promoted productivity. Finally, water availability greatly influenced fungal communities but did not interact with tree diversity to affect productivity; indicating possible resilience of tree communities to altered precipitation regimes and associated changes in fungal communities. Synthesis: Our study highlights the crucial role that fungal communities play in shaping the relationship between tree diversity, traits and productivity, and resilience to altered water availability.

Diversity‐conditioned soil strengthens plant diversity–productivity relationship

Abstract How biodiversity affects terrestrial productivity is important to the maintenance of ecosystem services under global change. Although the crucial role of plant–soil feedbacks (PSF) in determining diversity–productivity relationship has been increasingly recognized in recent years, its legacy effects on subsequent diversity–productivity relationship are still unclear. We conducted a classic PSF experiment to assess how plant diversity‐conditioned soils influenced subsequent plant diversity–productivity relationships, where three plant diversity levels (1, 4 and 8 species) were planted in soils conditioned at three diversity levels (conditioned by 1, 4 and 8 species for 3 years). In addition, to test the role of soil microbial diversity in mediating the effects of soil conditioning diversity, the three plant diversity levels were planted with low, moderate and high soil biodiversity created by a soil inoculum dilution. The results showed that plant productivities were promoted by mixed‐conditioned soils (4 and 8 species) comparing to mono‐conditioned soils (1 species). Productivity was positively related to planted diversity in mixed‐conditioned soils, while showed no relation with planted diversity in mono‐conditioned soils. Productivity was promoted by soil biodiversity when 4 and 8 species were mixed planted, while did not change when 1 species was planted. Synthesis and applications . Our results highlight that PSF is crucial to strengthen the positive effects of biodiversity on productivity, implying that diversifying cropping systems should be encouraged in agroecosystem management to benefit from positive PSF effects. The importance of soil legacy for optimizing plant productivity is particularly important for conditioning soils with an intermediate number of plant species.

Remote Sensing‐Based Forest Modeling Reveals Positive Effects of Functional Diversity on Productivity at Local Spatial Scale

AbstractForest biodiversity is critical for many ecosystem functions and services. Yet, it remains uncertain how plant functional diversity influences ecosystem functioning across environmental gradients and contiguous larger areas. We integrated remote sensing and terrestrial biosphere modeling to explore functional diversity–productivity relationships at multiple spatial scales for a heterogeneous forest ecosystem in Switzerland. We initialized forest structure and composition in the ecosystem demography model (ED2) through a combination of ground‐based surveys, airborne laser scanning and imaging spectroscopy for forest patches at 10 × 10‐m spatial grain. We derived morphological and physiological forest traits and productivity from model simulations at patch‐level to relate morphological and physiological aspects of functional diversity to the average productivity from 2006 to 2015 at 20 × 20 to 100 × 100‐m spatial extent. We did this for model simulations under observed and experimental conditions (mono‐soils, mono‐cultures and mono‐structures). Functional diversity increased productivity significantly (p &lt; 0.001) across all simulations at 20 × 20 to 30 × 30 m scale, but at 100 × 100‐m scale positive relationships disappeared under homogeneous soil conditions potentially due to the low beta diversity of this forest and the saturation of functional richness represented in the model. Although local functional diversity was an important driver of productivity, environmental context underpinned the variation of productivity (and functional diversity) at larger spatial scales. In this study, we could show that the integration of remotely sensed information on forest composition and structure into terrestrial biosphere models is important to fill knowledge gaps about how plant biodiversity affects carbon cycling and biosphere feedbacks onto climate over large contiguous areas.

The structure of root-associated fungal communities is related to the long-term effects of plant diversity on productivity.

Root-associated fungi could play a role in determining both the positive relationship between plant diversity and productivity in experimental grasslands, and its strengthening over time. This hypothesis assumes that specialized pathogenic and mutualistic fungal communities gradually assemble over time, enhancing plant growth more in species-rich than in species-poor plots. To test this hypothesis, we used high-throughput amplicon sequencing to characterize root-associated fungal communities in experimental grasslands of 1 and 15 years of age with varying levels of plant species richness. Specifically, we tested whether the relationship between fungal communities and plant richness and productivity becomes stronger with the age of the experimental plots. Our results showed that fungal diversity increased with plant diversity, but this relationship weakened rather than strengthened over the two time points. Contrastingly, fungal community composition showed increasing associations with plant diversity over time, suggesting a gradual build-up of specific fungal assemblages. Analyses of different fungal guilds showed that these changes were particularly marked in pathogenic fungi, whose shifts in relative abundance are consistent with the pathogen dilution hypothesis in diverse plant communities. Our results suggest that root-associated fungal pathogens play more specific roles in determining the diversity-productivity relationship than other root-associated plant symbionts.

Linking plant diversity-productivity relationships to plant functional traits of dominant species and changes in soil properties in 15-year-old experimental grasslands.

Positive plant diversity-productivity relationships are known to be driven by complementary resource use via differences in plant functional traits. Moreover, soil properties related to nutrient availability were shown to change with plant diversity over time; however, it is not well-understood whether and how such plant diversity-dependent soil changes and associated changes in functional traits contribute to positive diversity-productivity relationships in the long run. To test this, we investigated plant communities of different species richness (1, 2, 6, and 9 species) in a 15-year-old grassland biodiversity experiment. We determined community biomass production and biodiversity effects (net biodiversity [NEs], complementarity [CEs], and selection effects [SEs]), as well as community means of plant functional traits and soil properties. First, we tested how these variables changed along the plant diversity gradient and were related to each other. Then, we tested for direct and indirect effects of plant and soil variables influencing community biomass production and biodiversity effects. Community biomass production, NEs, CEs, SEs, plant height, root length density (RLD), and all soil property variables changed with plant diversity and the presence of the dominant grass species Arrhenatherum elatius (increase except for soil pH, which decreased). Plant height and RLD for plant functional traits, and soil pH and organic carbon concentration for soil properties, were the variables with the strongest influence on biomass production and biodiversity effects. Our results suggest that plant species richness and the presence of the dominant species, A. elatius, cause soil organic carbon to increase and soil pH to decrease over time, which increases nutrient availability favoring species with tall growth and dense root systems, resulting in higher biomass production in species-rich communities. Here, we present an additional process that contributes to the strengthening positive diversity-productivity relationship, which may play a role alongside the widespread plant functional trait-based explanation.

Grazing altered the plant diversity-productivity relationship in the Jianghan plain of the Yangtze River basin

PurposeThe Jianghan Plain is located in the middle reaches of the Yangtze River, characterized by high precipitation, flat terrain, and high vegetation cover. Livestock grazing is one of the major agricultural activities. Heavy grazing in some areas causes soil erosion and ecosystem degradation. We aim to quantify the effects of grazing of various grazing intensities on plant diversity and productivity as well as on soil nutrient dynamics in the area. MethodsTo examine the effects of grazing on plant diversity and productivity as well as on soil nutrient dynamics, we measured and compared the above-ground biomass (AGB), species composition (alpha and beta diversity indices), soil total phosphorus (STP), soil total nitrogen (STN), and soil organic carbon (SOC) under three grazing intensity levels: light grazing (LG), moderate grazing (MG) and heavy grazing (HG). ResultsThe results show that grazing intensity levels affected plant diversity, productivity, and soil nutrient dynamics differently. Species turnover refers to the rate of species substitution in different communities. The turnover dissimilarity value of species was 0.233 between LG and HG and 0.313 between LG and HG. AGB, STP, STN, Shannon-Wiener index, and plant productivity were all decreased under HG. In contrast, plant diversity (the Berger-Parker index) increased under HG. The relationships between plant diversity and productivity were also affected by grazing intensity. Under LG and MG, plant diversity was positively correlated with productivity, but became negative under HG. ConclusionsHG reduced plant diversity and altered the relationship between plant diversity and productivity, which caused ecosystem degradation. Thus, grazing management should aim to control the intensity of grazing at light to moderate levels to ensure the long-term sustainability of the ecosystem.

The key to temperate savanna restoration is to increase plant species richness reasonably

Changes in species composition and diversity-productivity relationships during vegetation succession are of great significance for the restoration of degraded grasslands. However, the human intervention of grassland restoration mostly considers the single ecological (diversity) or production (biomass) function of grasslands, and does not fully consider the relationships between the two to improve the restoration effects. In this study, three vegetation types (desert grassland, sandy grassland and temperate savanna) were considered to simulate the three stages of restoration of degraded temperate savanna (early, middle and late restoration). Changes in species composition, diversity, and diversity-productivity relationships during the temperate savanna restoration were explored through spatiotemporal substitution. The results showed that with the progress of succession, xerophytes decreased significantly, mesophytes and hygrophytes increased, C4 plants decreased gradually, and C3 plants increased. The change of species richness was the main reason for community differences in the process of community succession, and species replacement mainly occurred between communities in the early and middle stages of succession. Species richness increased significantly from early to late stage of restoration. Latitude was significantly negatively correlated with species diversity. In the process of vegetation restoration, the impact of species richness, Pielou’s evenness, and β-diversity on biomass gradually developed positively and continued to increase, while the Simpson index showed the opposite effect. This study provides references for the restoration of temperate savanna and emphasizes the ecological and productive functions of the grassland should be taken into account in the restoration strategy.

Shrub diversity in Mediterranean shrublands: Rescuer or victim of productivity?

AbstractAimsUnravelling the most prevalent causal direction between diversity and function in naturally recovered plant assemblages can greatly improve our understanding of the functional significance of diversity and its applications under the ongoing environmental changes. In this study, we apply a structural equation model framework to unravel the most plausible causal direction in the diversity–productivity relationship in subseral Mediterranean shrub‐dominated communities.MethodsTotal shrub cover (as a proxy of productivity when controlled by the time since land use cessation or the last wildfire), the number of species, and the number of functional types based on the dominant life forms (phanerophytes vs. chamaephytes), and the dominant foliar syndromes (deciduous vs. evergreen, needled vs. broad‐leaved), were sampled in 195 circular plots distributed along an elevation gradient ranging from 400 to 1400 m a.s.l. in the Central Iberian Peninsula. We first explored the distribution of functional types along the elevation gradient using a non‐metric multidimensional scaling (NMDS). Secondly, a structural equation model (SEM) framework using mixed‐effects models was defined to unveil the prevalent causal direction between diversity (species and functional types) and productivity at the landscape scale.ResultsModel selection using the Fisher'sCinformation criterion supported a causal direction from total shrub cover to diversity in this landscape. Interestingly, the best supported model also supported a positive relationship between species richness and the number of functional types, which in turn is driven by the total shrub cover along the elevation gradient.ConclusionsOur results suggest that more species might not necessarily boost productivity. On the contrary, ongoing warming temperatures and aridity, which are characteristic of low elevations compared to highlands, might significantly reduce the number of species (victim rather than rescuer) through deleterious effects on productivity.

Leaf nitrogen resorption is more important than litter nitrogen mineralization in mediating the diversity–productivity relationship along a nitrogen-limited temperate forest succession chronosequence

The resorption of nutrients by plants before litter fall and the mineralization of nutrients from plant litter by soil processes are both important pathways supporting primary productivity. While the positive relationship between plant biodiversity and primary productivity is widely accepted for natural ecosystems, the roles of nutrient resorption and mineralization in mediating that relationship remains largely unknown. Here, we quantified the relative importance of nitrogen (N) resorption and N mineralization in driving plant community N investment and the correlation between species diversity and community productivity along an N-limited successional chronosequence of the mixed broadleaved–Korean pine (Pinus koraiensis) forest in northeastern China. Leaf N resorption efficiency (NRE) at the community level increased significantly along the successional chronosequence, whereas litter N mineralization rate decreased significantly. Leaf NRE was more important than litter N mineralization rate in driving the diversity–productivity relationship. However, higher leaf NRE led to less N mineralization as succession progressed along the chronosequence. Our results highlight the importance of the N resorption pathway rather than the N mineralization pathway for forest N acquisition with community succession, and they provide mechanistic insights into the positive effects of biodiversity on ecosystem functioning. In future forest management practices, we recommend appropriate application of N fertilizer to mitigate the adverse effects of N-poor soil on seedling regeneration during late succession and thus maintain the sustainable development of temperate forest ecosystems.

Effects of disturbance on functional diversity-productivity relationships of aquatic plant communities depend on nutrients and life-forms

Effects of disturbance on functional diversity-productivity relationships of aquatic plant communities depend on nutrients and life-forms

Relationship between Biomass and Biodiversity of Degraded Grassland in the Sanjiangyuan Region of Qinghai–Tibet Plateau

Understanding the mechanisms of diversity–productivity relationships is a central question in community ecology. Grazing is the main driving force affecting biodiversity, function, and stability of grassland ecosystems, and thus should play an important role in mediating diversity-productivity relationships. In this study, we examined the effect of grazing intensity on both aboveground biomass and biodiversity and explored the relationship between them in alpine meadow ecosystems in Sanjiangyuan, which is the source of the Yangtze, Yellow, and Lancang rivers. The results showed that the aboveground biomass and species richness decreased significantly due to multi-state succession in alpine meadows caused by long-term grazing, while the Shannon–Wiener index and Pielou evenness index decreased and then increased with increasing grazing intensity. The relationship between the aboveground biomass and biodiversity was U-shaped. Our results highlighted the opposite pattern of the diversity–productivity relationship under low and medium grazing intensity versus an extremely high grazing intensity; evenness contributed largely to this pattern. This study provided a new perspective on grassland management and the relationship between productivity and biodiversity. Attention should be paid to rational grazing to restore biodiversity and ecosystem functions and services in alpine meadows.