Long-term warming increased carbon sequestration capacity in a humid subtropical forest.

Tropical and subtropical forests play a crucial role in global carbon (C) pools, and their responses to warming can significantly impact C-climate feedback and predictions of future global warming. Despite earth system models projecting reductions in land C storage with warming, the magnitude of this response varies greatly between models, particularly in tropical and subtropical regions. Here, we conducted a field ecosystem-level warming experiment in a subtropical forest in southern China, by translocating mesocosms (ecosystem composed of soils and plants) across 600 m elevation gradients with temperature gradients of 2.1°C (moderate warming), to explore the response of ecosystem C dynamics of the subtropical forest to continuous 6-year warming. Compared with the control, the ecosystem C stock decreased by 3.8% under the first year of 2.1°C warming; but increased by 13.4% by the sixth year of 2.1°C warming. The increased ecosystem C stock by the sixth year of warming was mainly attributed to a combination of sustained increased plant C stock due to the maintenance of a high plant growth rate and unchanged soil C stock. The unchanged soil C stock was driven by compensating and offsetting thermal adaptation of soil microorganisms (unresponsive soil respiration and enzyme activity, and more stable microbial community), increased plant C input, and inhibitory C loss (decreased C leaching and inhibited temperature sensitivity of soil respiration) from soil drying. These results suggest that the humid subtropical forest C pool would not necessarily diminish consistently under future long-term warming. We highlight that differential and asynchronous responses of plant and soil C processes over relatively long-term periods should be considered when predicting the effects of climate warming on ecosystem C dynamics of subtropical forests.

Lymphatic endothelial-like cells promote glioblastoma stem cell growth through cytokine-driven cholesterol metabolism.

Glioblastoma is the most lethal primary brain tumor with glioblastoma stem cells (GSCs) atop a cellular hierarchy. GSCs often reside in a perivascular niche, where they receive maintenance cues from endothelial cells, but the role of heterogeneous endothelial cell populations remains unresolved. Here, we show that lymphatic endothelial-like cells (LECs), while previously unrecognized in brain parenchyma, are present in glioblastomas and promote growth of CCR7-positive GSCs through CCL21 secretion. Disruption of CCL21-CCR7 paracrine communication between LECs and GSCs inhibited GSC proliferation and growth. LEC-derived CCL21 induced KAT5-mediated acetylation of HMGCS1 on K273 in GSCs to enhance HMGCS1 protein stability. HMGCS1 promoted cholesterol synthesis in GSCs, favorable for tumor growth. Expression of the CCL21-CCR7 axis correlated with KAT5 expression and HMGCS1K273 acetylation in glioblastoma specimens, informing patient outcome. Collectively, glioblastomas contain previously unrecognized LECs that promote the molecular crosstalk between endothelial and tumor cells, offering potentially alternative therapeutic strategies.

Climate change-related biodiversity fluctuations and composition changes in an old-growth subtropical forest: A 26-yr study.

The detection and attribution of biodiversity change is of great scientific interest and central to policy effects aimed at meeting biodiversity targets. Yet, how such a diverse climate scenarios influence forest biodiversity and composition dynamics remains unclear, particularly in high diversity systems of subtropical forests. Here we used data collected from the permanent sample plot spanning 26 years in an old-growth subtropical forest. Combining various climatic events (extreme drought, subsequent drought, warming, and windstorm), we analyzed long-term dynamics in multiple metrics: richness, turnover, density, abundance, reordering and stability. We did not observe consistent and directional trends in species richness under various climatic scenarios. Still, drought and windstorm events either reduced species gains or increased species loss, ultimately increased species turnover. Tree density increased significantly over time as a result of rapid increase in smaller individuals due to mortality in larger trees. Climate events caused rapid changes in dominant populations due to a handful of species undergoing strong increases or declines in abundance over time simultaneously. Species abundance composition underwent significant changes, particularly in the presence of drought and windstorm events. High variance ratio and species synchrony weaken community stability under various climate stress. Our study demonstrates that all processes underlying forest community composition changes often occur simultaneously and are equally affected by climate events, necessitating a holistic approach to quantifying community changes. By recognizing the interconnected nature of these processes, future research should accelerate comprehensive understanding and predicting of how forest vegetation responds to global climate change.

Mixed plantations do not necessarily provide higher ecosystem multifunctionality than monoculture plantations.

Forest stand transformation is a crucial strategy for enhancing the productivity and stability of planted forest ecosystems and maximizing their ecosystem functions. However, understanding forest ecosystem multifunctionality responses to various stand transformation methods remains limited. In this study, we assessed ecosystem multifunctionality, encompassing nutrient cycling, carbon stocks, water regulation, decomposition, wood production, and symbiosis, under different stand transformation methods (Chinese fir monoculture, mixed conifer and broad-leaf, broad-leaf mixed, and secondary forests). We also identified key factors contributing to variations in ecosystem multifunctionality. The results showed that Chinese fir plantations were more conducive to carbon stock creation, while broad-leaved mixed plantations excelled in water regulation. Secondary forests exhibited higher ecosystem multifunctionality than other plantation types, with Chinese fir plantations displaying the highest multifunctionality, significantly surpassing mixed coniferous and broad-leaved plantations. Our findings further revealed that soil nutrients and plant diversity have significant impacts on ecosystem multifunctionality. In summary, stand transformation profoundly influences ecosystem multifunctionality, and mixed plantations do not necessarily provide higher ecosystem multifunctionality than monoculture plantations.

Long-term seawall barriers lead to the formation of an urban coastal lagoon with increased antibiotic resistome.

Urbanization has increased the spread of antibiotic resistance genes (ARGs) impacting urban aquatic ecosystems and threatening human health. However, an overview of the antibiotic resistome in artificial coastal lagoons formed by coastal seawall construction is unclear. This study investigated the resistome of sediment in a coastal lagoon, established for over 60 years and found that the composition of the resistome in the lagoon sediments associated with the seawall significantly differed from that of marine sediment external to the seawall. Moreover, the diversity, number, relative abundance, and absolute abundance of the antibiotic resistome in the lagoon sediments were significantly higher compared to marine sediment. Network analyses revealed that more co-occurrences were found in lagoon sediment between bacterial communities, ARGs and mobile genetic elements (MGEs) than in marine sediments, suggesting that bacteria in lagoon sediments may be associated with multiple antibiotic resistances. Random forest and structural equation models showed that an increase in the absolute abundance of MGEs had a concomitant effect on the absolute abundance and diversity of ARGs, whereas increasing salinity decreased the absolute abundance of ARGs. This study provides a basis to assess the risk of resistome diffusion and persistence in an artificial coastal lagoon.

Photosynthetic and biochemical responses of four subtropical tree seedlings to reduced dry season and increased wet season precipitation and variable N deposition.

Interspecific variations in phenotypic plasticity of trees that are affected by climate change may alter the ecosystem function of forests. Seedlings of four common tree species (Castanopsis fissa, Michelia macclurei, Dalbergia odorifera and Ormosia pinnata) in subtropical plantations of southern China were grown in the field under rainout shelters and subjected to changing precipitation (48 L of water every 4 days in the dry season, 83 L of water every 1 day in the wet season; 4 g m-2 year-1 of nitrogen (N)), low N deposition (48 L of water every 2 days in the dry season, 71 L of water every 1 day in the wet season; 8 g m-2 year-1 N), high N deposition (48 L of water every 2 days in the dry season, 71 L of water every 1 day in the wet season; 10 g m-2 year-1 N) and their interactive effects. We found that the changes in seasonal precipitation reduced the light-saturated photosynthetic rate (Asat) for C. fissa due to declining area-based foliar N concentrations (Na). However, we also found that the interactive effects of changing precipitation and N deposition enhanced Asat for C. fissa by increasing foliar Na concentrations, suggesting that N deposition could alleviate N limitations associated with changing precipitation. Altered precipitation and high N deposition reduced Asat for D. odorifera by decreasing the maximum electron transport rate for RuBP regeneration (Jmax) and maximum rate of carboxylation of Rubisco (Vcmax). Ormosia pinnata under high N deposition exhibited increasing Asat due to higher stomatal conductance and Vcmax. The growth of D. odorifera might be inhibited by changes in seasonal precipitation and N deposition, while O. pinnata may benefit from increasing N deposition in future climates. Our study provides an important insight into the selection of tree species with high capacity to tolerate changing precipitation and N deposition in subtropical plantations.

Climate change reshapes plant trait spectrum to explain biomass dynamics in an old-growth subtropical forest.

Climate change leads to novel species interactions and continues to reshuffle ecological communities, which significantly declines carbon accumulation rates in mature forests. Still, little is known about the potential influence of multiple global change factors on long-term biomass dynamics and functional trait combinations. We used temporal demographic records spanning 26 years and extensive databases of functional traits to assess how old-growth subtropical forest biomass dynamics respond to various climatic change scenarios (extreme drought, subsequent drought, warming, elevated CO2 concentrations, and windstorm). We found that the initial severe drought, subsequent drought and windstorm events increased biomass loss due to tree mortality, which exceeded the biomass gain produced by survivors and recruits, ultimately resulting in more negative net biomass balances. These drought and windstorm events caused massive biomass loss due to tree mortality that tended towards acquisition species with high hydraulic efficiency, whereas biomass growth from survivors and recruits tended to consist of acquisition species with high hydraulic safety. Compensatory growth in this natural forest provided good explanation for the increase in biomass growth after drought and windstorm events. Notably, these dominant-species transitions reduced carbon storage and residence time, forming a positive carbon-climate feedback loop. Our findings suggest that climate changes could alter functional strategies and cause shifts in new dominant species, which could greatly reduce ecological functions and carbon gains of old-growth subtropical forests.

Host-Parasitoid Phenology, Distribution, and Biological Control under Climate Change.

Climate change raises a serious threat to global entomofauna-the foundation of many ecosystems-by threatening species preservation and the ecosystem services they provide. Already, changes in climate-warming-are causing (i) sharp phenological mismatches among host-parasitoid systems by reducing the window of host susceptibility, leading to early emergence of either the host or its associated parasitoid and affecting mismatched species' fitness and abundance; (ii) shifting arthropods' expansion range towards higher altitudes, and therefore migratory pest infestations are more likely; and (iii) reducing biological control effectiveness by natural enemies, leading to potential pest outbreaks. Here, we provided an overview of the warming consequences on biodiversity and functionality of agroecosystems, highlighting the vital role that phenology plays in ecology. Also, we discussed how phenological mismatches would affect biological control efficacy, since an accurate description of stage differentiation (metamorphosis) of a pest and its associated natural enemy is crucial in order to know the exact time of the host susceptibility/suitability or stage when the parasitoids are able to optimize their parasitization or performance. Campaigns regarding landscape structure/heterogeneity, reduction of pesticides, and modelling approaches are urgently needed in order to safeguard populations of natural enemies in a future warmer world.

Carbon sequestration and storage capacity of Chinese fir at different stand ages.

In southern China, Chinese fir Cunninghamia lanceolata is one of the most important native conifer trees, widely used in afforestation programs. This area has the largest forestland atmospheric carbon sink, and a relatively young stand age characterizes these forests. However, how C. lanceolata forests evolved regarding their ability to sequester carbon remains unclear. Here we present data on carbon storage and sequestration capacity of C. lanceolata at six stand ages (5-, 10-, 15-, 20-, 30- and 60 - year-old stands). Results show that the carbon stock in trees, understory, vegetation, litter, soil, and ecosystem significantly increased with forest age. The total ecosystem carbon stock increased from 129.11 to 348.43 Mg ha-1 in the 5- and 60 - year-old stands. The carbon sequestration rate of C. lanceolata shows an overall increase in the first two stand intervals (5-10 and 10-15), peaks in the 15-20 stand intervals, and then decreases in the 20-30 and 30-60 stand intervals. Our result revealed that carbon sequestration rate is a matter of tree age, with the highest sequestration rates occurring in the middle age forest (15-20 - year-old). Therefore, this information may be useful for national climate change mitigation actions and afforestation programs, since forests are primarily planted for this purpose.

Acidity of Soil and Water Decreases in Acid-Sensitive Forests of Tropical China.

Acid deposition in China has been declining since the 2000s. While this may help mitigate acidification in forest soils and water, little is known about the recovery of soils and water from previous severe acidification in tropical China. Here, we assessed the chemistry of mineral soils, water, and acid gases (SO2 and NOx) from three successional forest types in tropical China from 2000 to 2022. Our results showed that soil pH increased synchronously from 3.9 (2000-2015) to 4.2 (2016-2022) across all three forest types, with exchangeable acid initially decreasing and thereafter stabilizing. Surface and ground water pH also gradually increased throughout the monitoring period. Soil pH recovery was stronger in the primary than in the planted forest. However, soil pH recovery lagged behind the increase in rainfall pH by approximately a decade. The recovery of soil pH was likely related to the positive effects of the dissolution of Al/Fe-hydroxysulfate mineral and subsequent sulfur desorption on soil acid-neutralizing capacity, increased soil organic matter, and climate warming, but was likely moderated by increased exchangeable aluminum and potentially proton-producing hydroxysulfate mineral dissolution that caused the lagged soil pH recovery. Surface and ground water pH recovery was attributed to increased water acid-neutralizing capacity. Our study reports the potential for the recovery of acidified soil and water following decreased acid deposition and provides new insights into the functional recovery of acid-sensitive forests.

Distinct patterns of the soil and phyllosphere antibiotic resistome in natural forest ecosystems under an altitudinal gradient.

Warming affects microbial functioning of soil and the phyllosphere across global ecosystems. However, little is known about the impact of increasing temperature on antibiotic resistome profiles in natural forests. To address this issue, we investigated antibiotic resistance genes (ARGs) in both soil and the plant phyllosphere using an experimental platform established in a forest ecosystem that delivers a temperature difference of 2.1 °C along an altitudinal gradient. Principal Coordinate Analysis (PCoA) showed that there were significant differences in the composition of soil and plant phyllosphere ARGs at different altitudes (P = 0.001). The relative abundance of phyllosphere ARGs and mobile genetic elements (MGEs) and soil MGEs increased with temperature. More resistance gene classes increased in abundance in the phyllosphere (10 classes) than soil (2 classes), and a Random Forest model analysis suggested that phyllosphere ARGs were more sensitive to temperature change than soil. Increasing temperature as a direct consequence of an altitudinal gradient, and the relative abundance of MGEs were the main drivers that shaped the profiles of ARGs in the phyllosphere and soil. Biotic and abiotic factors affected phyllosphere ARGs indirectly via MGEs. This study enhances our understanding of the influence of altitude gradients on resistance genes in natural environments.

Carbon storage capacity of Castanopsis hystrix plantations at different stand-ages in South China.

The establishment of forest plantations is an excellent silvicultural alternative to improve atmospheric carbon (C) sequestration for climate change mitigation. In recent years, the importance of forest growth and C dynamics at different stand ages have drawn huge attention for investigation. To evaluate the impacts of different stand ages on the C storage capacity of Castanopsis hystrix plantations ecosystems, we measured biomass and C content in trees, understory, litter, and soil components from field measurements at different stand ages, i.e., 6-, 10-, 15-, 25-, and 34-year-old stands. Results showed that the C stocks in trees, understory vegetation, litter, soil and the whole ecosystem increased steadily with stand age. C. hystrix C storage capacity in the 6-, 10-, 15-, 25-, and 34-year-old stands were 29.17, 56.18, 85.60, 132.19 and 157.79 Mg ha-1, respectively, while the total ecosystem C storage capacity was 68.11, 106.11, 136.13, 187.34 and 226.14 Mg ha-1, respectively. Meanwhile, the C sequestration rate in the 6-10, 10-15, 15-25 and 25-35-year-old stands were 675.28, 588.35, 465.97 and 284.39 g m2 year-1, respectively. Similarly, total biomass of trees, understory, and litter increased with stand age. Our study indicated that C. hystrix plantations are still developing in the area, since live biomass and soil C continue to accumulate despite reduced C sequestration rates. The information provided here highlight the C stock and C sequestration rates of C. hystrix at different stand ages, providing baseline information on the C dynamics of young and older stand of C. hystrix in this region; Hence, such knowledge could be useful for designing more realistic policies to mitigate climate change, such as programs to maintain continuous forest growth.

Distinct Responses of Abundant and Rare Soil Bacteria to Nitrogen Addition in Tropical Forest Soils.

Soil microbial responses to anthropogenic nitrogen (N) enrichment at the overall community level has been extensively studied. However, the responses of community dynamics and assembly processes of the abundant versus rare bacterial taxa to N enrichment have rarely been assessed. Here, we present a study in which the effects of short- (2 years) and long-term (13 years) N additions to two nearby tropical forest sites on abundant and rare soil bacterial community composition and assembly were documented. The N addition, particularly in the long-term experiment, significantly decreased the bacterial α-diversity and shifted the community composition toward copiotrophic and N-sensitive species. The α-diversity and community composition of the rare taxa were more affected, and they were more closely clustered phylogenetically under N addition compared to the abundant taxa, suggesting the community assembly of the rare taxa was more governed by deterministic processes (e.g., environmental filtering). In contrast, the abundant taxa exhibited higher community abundance, broader environmental thresholds, and stronger phylogenetic signals under environmental changes than the rare taxa. Overall, these findings illustrate that the abundant and rare bacterial taxa respond distinctly to N addition in tropical forests, with higher sensitivity of the rare taxa, but potentially broader environmental acclimation of the abundant taxa. IMPORTANCE Atmospheric nitrogen (N) deposition is a worldwide environmental problem and threatens biodiversity and ecosystem functioning. Understanding the responses of community dynamics and assembly processes of abundant and rare soil bacterial taxa to anthropogenic N enrichment is vital for the management of N-polluted forest soils. Our sequence-based data revealed distinct responses in bacterial diversity, community composition, environmental acclimation, and assembly processes between abundant and rare taxa under N-addition soils in tropical forests. These findings provide new insight into the formation and maintenance of bacterial diversity and offer a way to better predict bacterial responses to the ongoing atmospheric N deposition in tropical forests.

Distinct patterns of soil bacterial and fungal community assemblages in subtropical forest ecosystems under warming.

Climate change globally affects soil microbial community assembly across ecosystems. However, little is known about the impact of warming on the structure of soil microbial communities or underlying mechanisms that shape microbial community composition in subtropical forest ecosystems. To address this gap, we utilized natural variation in temperature via an altitudinal gradient to simulate ecosystem warming. After 6 years, microbial co-occurrence network complexity increased with warming, and changes in their taxonomic composition were asynchronous, likely due to contrasting community assembly processes. We found that while stochastic processes were drivers of bacterial community composition, warming led to a shift from stochastic to deterministic drivers in dry season. Structural equation modelling highlighted that soil temperature and water content positively influenced soil microbial communities during dry season and negatively during wet season. These results facilitate our understanding of the response of soil microbial communities to climate warming and may improve predictions of ecosystem function of soil microbes in subtropical forests.

Comprehensive genome-wide identification and expression profiling of ADF gene family in Citrus sinensis, induced by endophytic colonization of Beauveria bassiana.

Endophytic entomopathogenic species are known to systematically colonize host plants and form symbiotic associations that benefit the plants they live with. The actin-depolymerizing factors (ADFs) are a group of gene family that regulate growth, development, and defense-related functions in plants. Systematic studies of ADF family at the genome-wide level and their expression in response to endophytic colonization are essential to understand its functions but are currently lacking in this field. 14ADF genes were identified and characterized in the Citrus sinensis genome. The ADF genes of C. sinensis were classified into five groups according to the phylogenetic analysis of plant ADFs. Additionally, the cis-acting analysis revealed that these genes play essential role in plant growth/development, phytohormone, and biotic and abiotic responses; and the expression analysis showed that the symbiotic interactions generate a significant expression regulation level of ADF genes in leaves, stems and roots, compared to controls; thus enhancing seedlings' growth. Additionally, the 3D structures of the ADF domain were highly conserved during evolution. These results will be helpful for further functional validation of ADFs candidate genes and provide important insights into the vegetative growth, development and stress tolerance of C. sinensis in responses to endophytic colonization by B. bassiana.

Tree species richness as an important biotic factor regulates the soil phosphorus density in China's mature natural forests.

Tree species richness has been recognized as an underlying driving factor for regulating soil phosphorus (P) status in many site-specific studies. However, it remains poorly understood whether this is true at broad scales where soil P strongly rely on climate, soil type and vegetation type. Here, based on the data of 946 mature natural forest sites from a nationwide field survey in China, we analyzed the impact of tree species richness on soil P density of China's mature natural forests (deciduous coniferous forest, DCF; evergreen coniferous forest, ECF; deciduous broad-leaved forest, DBF; evergreen broad-leaved forest, EBF; and mixed coniferous and broad-leaved forest, MF). Our results showed that tree species richness had a negative effect on soil P density in China's mature natural forests. The Random Forest regression model showed that the relative importance of tree species richness to soil P density was second only to the climate factors (mean annual temperature, MAT; mean annual precipitation, MAP). In addition, the structural equation model (SEM) results showed that the goodness fit of SEM increased when the tree species richness was included into the model. These results suggested that tree species richness was an important factor in regulating the China's mature natural forests soil P density. Furthermore, the SEM results showed that the decreased soil P density was related to the increase in ANPP and the decrease in litter P concentration induced by tree species richness. This result indicates that tree species richness could facilitate plant P absorption and inhibit plant P return into the soil, and thus reducing the soil P density in China's mature natural forests. In conclusion, we found tree species richness was an important biotic factor in regulating soil P density at broad scales, which should be fully considered in Earth models that represent P cycle.

A pilot study to investigate the alteration of gut microbial profile in Dip2a knockout mice / Un estudio piloto para investigar la alteración del perfil microbiano intestinal en ratones knockout para Dip2a

Accumulating evidence has pointed out that the gut-brain axis plays important roles in the etiology of autism spectrum disorder (ASD). Gut dysbiosis was reported in both ASD human patients and animal models. Dip2a was identified as a human ASD candidate gene. Deletion of Dip2a led to dendritic spine dysfunction and autistic-like behaviors in mice. To further investigate if Dip2a deletion leads to gut dysbiosis, we used 16S rDNA sequencing to study the gut microbiota in Dip2a KO mice. In both co-housed and separated breeding conditions, deletion of Dip2a could affect the gut microbiome composition. The probiotic bacteria, Lactobacillus and Bifidobacterium, became less abundant, while some potentially harmful bacteria, Alistipes, Lachnospiraceae_NK4A136_group, Clostridium, Desulfovibrio, and Enterorhabdus, became more abundant. We further found that probiotic treatment could help to reconstitute the gut microbiome composition in Dip2a KO mice. Altogether, these data showed DIP2A is required for the proper composition of gut microbiota, and the probiotics have potential roles in rectifying the gut microbiota in Dip2a KO mice.(AU)

Warming drives sustained plant phosphorus demand in a humid tropical forest.

Phosphorus (P) is often one of the most limiting nutrients in highly weathered soils of humid tropical forests and may regulate the responses of carbon (C) feedback to climate warming. However, the response of P to warming at the ecosystem level in tropical forests is not well understood because previous studies have not comprehensively assessed changes in multiple P processes associated with warming. Here, we detected changes in the ecosystem P cycle in response to a 7-year continuous warming experiment by translocating model plant-soil ecosystems across a 600-m elevation gradient, equivalent to a temperature change of 2.1°C. We found that warming increased plant P content (55.4%) and decreased foliar N:P. Increased plant P content was supplied by multiple processes, including enhanced plant P resorption (9.7%), soil P mineralization (15.5% decrease in moderately available organic P), and dissolution (6.8% decrease in iron-bound inorganic P), without changing litter P mineralization and leachate P. These findings suggest that warming sustained plant P demand by increasing the biological and geochemical controls of the plant-soil P-cycle, which has important implications for C fixation in P-deficient and highly productive tropical forests in future warmer climates.

A pilot study to investigate the alteration of gut microbial profile in Dip2a knockout mice.

Accumulating evidence has pointed out that the gut-brain axis plays important roles in the etiology of autism spectrum disorder (ASD). Gut dysbiosis was reported in both ASD human patients and animal models. Dip2a was identified as a human ASD candidate gene. Deletion of Dip2a led to dendritic spine dysfunction and autistic-like behaviors in mice. To further investigate if Dip2a deletion leads to gut dysbiosis, we used 16S rDNA sequencing to study the gut microbiota in Dip2a KO mice. In both co-housed and separated breeding conditions, deletion of Dip2a could affect the gut microbiome composition. The probiotic bacteria, Lactobacillus and Bifidobacterium, became less abundant, while some potentially harmful bacteria, Alistipes, Lachnospiraceae_NK4A136_group, Clostridium, Desulfovibrio, and Enterorhabdus, became more abundant. We further found that probiotic treatment could help to reconstitute the gut microbiome composition in Dip2a KO mice. Altogether, these data showed DIP2A is required for the proper composition of gut microbiota, and the probiotics have potential roles in rectifying the gut microbiota in Dip2a KO mice.

Natural forests promote phosphorus retention in soil.

Soil phosphorus (P) availability often limits plant productivity. Classical theories suggest that total P content declines at the temporal scale of pedogenesis, and ecosystems develop toward the efficient use of scarce P during succession. However, the trajectory of ecosystem P within shorter time scales of succession remains unclear. We analyzed changes to P pools at the early (I), middle (II), and late (III) stages of growth of plantation forests (PFs) and the successional stages of natural forests (NFs) at 1969 sites in China. We found significantly lower P contents at later growth stages compared to earlier ones in the PF (p < .05), but higher contents at late successional stages than in earlier stages in the NF (p < .05). Our results indicate that increasing P demand of natural vegetation during succession, may raise, retain, and accumulate P from deeper soil layers. In contrast, ecosystem P in PF was depleted by the more rapidly increasing demand outpacing the development of a P-efficient system. We advocate for more studies to illuminate the mechanisms for determining the divergent changes, which would improve forest management and avoid the vast degradation of PF ecosystems suffering from the ongoing depletion of P.