Liana Species Research Articles

Liana versus tree seedling responses to spatial and temporal variation in dry season severity

AbstractLianas are key components of tropical forests, particularly at sites with more severe dry seasons. In contrast, trees are more abundant and speciose in wetter areas. The seasonal growth advantage (SGA) hypothesis postulates that such contrasting distributions are produced by higher liana growth relative to trees during seasonal droughts. The SGA has been investigated for larger size classes (e.g., ≥5 cm diameter at 1.3 m, dbh), but rarely for seedlings. Using eight annual censuses of >12,000 seedlings of 483 tree and liana species conducted at eight 1‐ha plots spanning a strong rainfall gradient in central Panama, we evaluated whether liana seedlings had higher growth and/or survival rates than tree seedlings at sites with stronger droughts. We also tested whether an extreme El Niño drought during the study period had a more negative effect on tree compared to liana seedlings. The absolute density of liana seedlings was similar across the rainfall gradient, ranging from 0.32 individuals/m2 (0.20–0.49, 95% credible interval [CI]) at the driest end of the gradient and 0.27 individuals/m2 (0.13–0.51 95% CI) at the wettest end of the gradient. The relative density of liana seedlings compared to tree seedlings was higher at sites with stronger dry seasons (0.27, 0.21–0.33, 95% CI), compared to wetter sites (0.12, 0.04–0.20 95% CI), due to lower tree seedling densities at drier sites. However, liana seedlings did not grow or survive better than tree seedlings in drier sites compared to wetter sites. Tree seedlings were more negatively impacted in terms of mortality by the extreme El Niño drought than liana seedlings, with an increase in annual mortality rate of 0.013 (0.003–0.025 95% CI) compared to lianas of −0.009 (−0.028 to 0.008 95% CI), but not growth. Our results indicate that lianas do not have a SGA over trees at the seedling stage. Instead, higher survival of liana versus tree seedlings during severe droughts or differences in liana versus tree fecundity or germination across the rainfall gradient likely explain why liana seedlings have higher relative densities at drier sites.

Wood Anatomical and Demographic Similarities Between Self-Standing Liana and Tree Seedlings in Tropical Dry Forests of Colombia.

Canopy lianas differ considerably from trees in terms of wood anatomical structure, and they are suggested to have a demographic advantage-faster growth and higher survival-than trees. However, it remains unclear whether these anatomical and demographic differences persist at the seedling stage, when most liana species are self-standing and, consequently, might be ecologically similar to trees. We assessed how self-standing liana and tree seedlings differ in relation to wood anatomy, growth, and survival. We measured 12 wood traits and monitored seedling growth and survival over one year for 10 self-supporting liana and 10 tree seedling species from three tropical dry forests in Colombia. Liana and tree seedlings exhibited similar survival rates and wood anatomies for traits related to water storage and mechanical support. Yet, for traits associated with water transport, liana seedlings showed greater variability in vessel lumen size, while tree seedlings had higher vessel density. Also, the liana relative growth rate was significantly higher than for trees. These results indicate that, while self-supporting liana and tree seedlings are anatomically similar in terms of mechanical support and water storage-likely contributing to their similar survival rates-liana seedlings have a growth advantage, possibly due to more efficient water transport. These findings suggest that the well-documented anatomical and demographic differences between adult lianas and trees may depend on the liana's developmental stage, with more efficient water transport emerging as a key trait from early stages.

Keetia gordonii sp. nov. (Rubiaceae - Vanguerieae), a new species of threatened forest liana from Gabon

SummaryKeetia gordonii sp. nov. (Rubiaceae - Vanguerieae) a new species of forest liana from Gabon, is described and illustrated. The new species shows all the diagnostic characters of Keetia, such as pyrenes opening by an apical cap and seeds with tanniniferous endosperm, both of which are unrecorded in other genera of the tribe, flowers with a long-exserted style and erect anthers and a (usually) climbing habit. However, it is unique in the genus for its corolla with dense, appressed, brown hairs externally (vs glabrous or with a few hairs towards the apex), its glabrous disk (vs variously pubescent) and its seeds with a continuous tanniniferous layer in the outer part (vs with tanniniferous areas forming radial bands, or diffuse). Keetia gordonii is assigned to the Keetia hispida group of Guineo-Congolian African species. It is the first endemic Keetia species to be described from Gabon, although several others are awaiting description. On current evidence, the species appears to have six locations and is threatened by forest clearance. It is provisionally assessed using the IUCN (2012) standard as Vulnerable [VU B2ab(i,ii,iii,iv,v)].

Species assemblages and their drivers differ between trees and lianas in a seasonal evergreen forest in Thailand

AbstractDespite a long tradition in ecology of studying tree species assembly and its potential drivers in tropical forest communities, little information exists with respect to lianas (woody climbers), the second most abundant life form of woody plants in tropical forests. Lianas influence forest diversity and stability and provide critical resources for forest fauna. Using a unique dataset of a 30‐ha plot in Thailand, where tree and liana individuals were fully mapped, we investigated the degree to which local species assemblages of trees and lianas of different size classes (i.e., seedlings, established individuals, and large individuals) are related to local environmental conditions. We asked (1) What are the spatial patterns and environmental drivers of local tree and liana species assemblages? (2) How do such patterns and drivers differ among size classes? (3) Which species associate with these assemblages? Local assemblages of established trees showed substantial structuring by environmental variables, whereas we found only weakly structured assemblages of tree seedlings, large trees, and lianas of all size classes. Our results indicated that the biotic and abiotic drivers of local species assemblages differed strongly between tree and liana communities and across size classes. Species assemblages of trees were mainly driven by soil nutrients, leading to patchy assemblages associated with high base saturation (Alfisols) and assemblages associated with lower levels of base saturation and higher aluminum (Ultisols), whereas tree seedling assemblages were only weakly structured by riparian zones. In contrast, species assemblages of established and large lianas were primarily associated with forest canopy structure, separating low‐canopy forests from high‐canopy forests, whereas soil nutrients were the only factors associated with liana seedling assemblages. The weak environmental structuring of tree seedlings and large trees suggests that other mechanisms, such as stochastic disturbances, competition for space, or animal seed dispersal, may play an important role in structuring tree communities in this seasonal tropical forest. The weak patterns observed in liana communities across all life stages raise questions about the underlying mechanisms of liana community assembly, and further research should focus on liana niches, their dispersal mechanisms, and host tree relations.

Anatomy of a fossil liana from the Upper Cretaceous of British Columbia, Canada

Summary Fossil woods are preserved as calcareous permineralizations in the Upper Cretaceous Northumberland Formation on Collishaw Point, Hornby Island, British Columbia, Canada. They are well preserved, often including peripheral tissues, and reveal the diversity and structure of vegetation in the region ca. 72 million years ago. We describe a new genus and species based on two specimens. Two specimens were cut using a rock saw to expose the fossil wood in transverse and longitudinal sections. Thin sections were prepared using the cellulose acetate peel technique. Peels were mounted on slides with Eukitt mounting medium. Anatomical description follows the IAWA guidelines. We compared the anatomy of the fossils with that of other plants using data available in the published literature and the InsideWood database. The combination of wide vessels and high vessel frequency given the narrow diameter of the stem, combined with the abrupt increase in vessel diameter near the pith indicates this plant had hydraulic properties typical of a climbing plant (liana). The anatomy of the rays, the arrangement of the vessels and their pitting, and the thickness of the bark are also consistent with the climbing habit, but not diagnostic of any extant family. This is the second species of liana to be described from the Hornby Island assemblage, providing new information about the composition of structurally complex mixed conifer–angiosperm forests in the Late Cretaceous of western North America.

Isolated, neglected, and likely threatened: a new species of Magoniella (Polygonaceae) from the seasonally dry tropical forests of Northern Colombia and Venezuela revealed from nuclear, plastid, and morphological data.

Seasonally tropical dry forests (SDTFs) in the American tropics are a highly diverse yet poorly understood and endangered ecosystem scattered from Northern Mexico to Southern Argentina. One floristic element of the STDFs is the genus Magoniella (Polygonaceae), which includes two liana species, M. laurifolia and M. obidensis, which have winged fruits and are distributed from Costa Rica to Southern Brazil. In a field expedition to the SDTFs of the Colombian Caribbean in 2015, morphologically distinctive individuals of Magoniella were found. In this study, we investigated the species boundaries within Magoniella and determined the phylogenetic position of these morphologically distinctive individuals in the tribe Triplaridae. We compiled morphological trait data across 19 specimens of both species and produced newly sequenced nuclear-plastid DNA data for M. obidensis. Morphometric analyses revealed significant differences in fruit length and perianth size among individuals from the Colombian Caribbean compared to M. obidensis and bract length when compared to M. laurifolia. Maximum likelihood analysis of non-conflicting nuclear and plastid datasets placed the Colombian Caribbean individuals as sister to M. obidensis with maximum statistical support. Additionally, pairwise sequence comparisons of the nuclear ribosomal ITS and the lfy2i loci consistently showed 15-point mutations (10 transitions, five transversions) and six 2 bp-long substitutions that differ between M. obidensis and the Colombian Caribbean individuals. Our morphological and molecular evidence thus suggests that the Colombian Caribbean individuals of Magoniella represent a divergent population from M. laurifolia and M. obidensis, which we describe and illustrate as a new species, M. chersina. Additionally, we provide nomenclatural updates for M. laurifolia and M. obidensis. This study highlights the power of combining morphological and molecular evidence in documenting and naming plant diversity.

Lianas in tropical dry seasonal forests have a high hydraulic efficiency but not always a higher embolism resistance than lianas in rainforests.

Lianas have higher relative abundance and biomass in drier seasonal forests than in rainforests, but whether this difference is associated with their hydraulic strategies is unclear. Here, we investigate whether lianas of seasonally dry forests are safer and more efficient in water transport than rainforest lianas, explaining patterns of liana abundance. We measured hydraulic traits on five pairs of congeneric lianas of the tribe Bignonieae in two contrasting forest sites: the wet 'Dense Ombrophilous Forest' in Central Amazonia (~2 dry months) and the drier 'Semideciduous Seasonal Forest' in the inland Atlantic Forest (~6 dry months). We also gathered a broader database, including 197 trees and 58 liana species from different tropical forests, to compare hydraulic safety between habits and forest types. Bignonieae lianas from both forests had high and similar hydraulic efficiency but exhibited variability in resistance to embolism across forest types when phylogenetic relationships were taken into account. Three genera had higher hydraulic safety in the seasonal forest than in the rainforest, but species across both forests had similar positive hydraulic safety margins despite lower predawn water potential values of seasonal forest lianas. We did not find the safety-efficiency trade-off. Merging our results with previously published data revealed a high variability of resistance to embolism in both trees and lianas, independent of forest types. The high hydraulic efficiency of lianas detected here probably favours their rapid growth across tropical forests, but differences in hydraulic safety highlight that some species are highly vulnerable and may rely on other mechanisms to cope with drought. Future research on the lethal dehydration threshold and the connection between hydraulic resistance strategies and liana abundance could offer further insights into tropical forest dynamics under climatic threats.

Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan

Although self-medication in non-human animals is often difficult to document systematically due to the difficulty of predicting its occurrence, there is widespread evidence of such behaviors as whole leaf swallowing, bitter pith chewing, and fur rubbing in African great apes, orangutans, white handed gibbons, and several other species of monkeys in Africa, Central and South America and Madagascar. To the best of our knowledge, there is only one report of active wound treatment in non-human animals, namely in chimpanzees. We observed a male Sumatran orangutan (Pongo abelii) who sustained a facial wound. Three days after the injury he selectively ripped off leaves of a liana with the common name Akar Kuning (Fibraurea tinctoria), chewed on them, and then repeatedly applied the resulting juice onto the facial wound. As a last step, he fully covered the wound with the chewed leaves. Found in tropical forests of Southeast Asia, this and related liana species are known for their analgesic, antipyretic, and diuretic effects and are used in traditional medicine to treat various diseases, such as dysentery, diabetes, and malaria. Previous analyses of plant chemical compounds show the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, anti-fungal, antioxidant, and other biological activities of relevance to wound healing. This possibly innovative behavior presents the first systematically documented case of active wound treatment with a plant species know to contain biologically active substances by a wild animal and provides new insights into the origins of human wound care.

Consistent pattern in scaling relationships of leaf dry mass versus area of woody species co-occurring in dry-hot and wet-hot habitats

The scaling relationships between leaf dry mass (LDM) and surface area (LA) can reflect the efficiency of light harvesting and photosynthesis, as well as the ability of plants to withstand biotic and abiotic stress. However, it remains little unknown whether plants alter the scaling relationships of LDM and LA, as along with leaf mass investment per unit area in common species growing in different habitats with high temperature and contrasting water availability. This study involved measuring LA, LDM, and leaf morphological traits (e.g., leaf thickness, dry mass per unit area, and density) in 14 woody species (10 tree species, 2 shrub species, and 2 liana species) that co-occur in wet-hot (WH) and dry-hot (DH) habitats in southwest China. Our results showed that the scaling exponents (α) of LDM vs. LA were consistently greater than 1.0 (indicating the increase in LA fails to keep pace with increasing LDM) for all 14 common species at both sites, irrespective of their growth forms. Furthermore, species exhibited a higher leaf mass investment per unit area and leaf density at the DH site compared to the WH site. These results suggest that the law of “diminishing returns” applies to the scaling relationships of LDM and LA in common species inhabiting both types of habitats. Additionally, plants at the DH site increased leaf mass and density investments, potentially reflecting an essential adaptation to strong selective pressure experienced by plant species in that habitat. This study provides new insights into the scaling relationships of LDM and LA in contrasting habitats, enriching our understanding of the plant life-history strategies and adaptations in response to climate change.

Topographical gradient of the structure and diversity of a woody plant community in a seasonally dry tropical forest in northwestern Madagascar

AbstractFew studies have evaluated the structure and dynamics of forests in Madagascar with high levels of endemism. Ankarafantsika National Park holds the largest of the remaining primary dry forests in northwestern Madagascar, where most of the forests have been lost or degraded by fire and other human activities. In this primary forest, we established a 15‐ha forest dynamics monitoring plot and mapped and identified all woody stems with a diameter at breast height (DBH) ≥5 cm. The forest stand was characterized by small‐sized individuals (75% of stems with DBH <10 cm, with 99% of trees with height <15 m), encompassing 35,758 tree and 513 liana individuals belonging to 160 species in 53 families (including 20 species of lianas accounting for 1.4% of the stems). Most species‐rich families were Rubiaceae, Fabaceae, Lamiaceae, and Malvaceae, which together encompassed 43 tree species and 23% of all tree individuals. The plot was located on a hill consisting of white sand at elevations from 150 to 200 m, with a gentle slope down from southwest to northeast. Over this elevation gradient, stem density and species diversity increased with elevation, while tree height and diameter decreased. The most abundant two species, Drypetes perrieri (Putranjivaceae) and Noronhia alleizettei (Oleaceae) are evergreen, suggesting the importance of a nutrient conservation strategy. These results provide the foundational knowledge necessary for the conservation and restoration of natural semi‐deciduous dry forests that used to cover large areas in northwestern Madagascar until recently.

Climbing mechanisms as a central trait to understand the ecology of lianas across the tropics

AbstractAimsLianas are a central component of tropical forests. However, how the type of climbing mechanisms is related to the functional and taxonomic diversity of lianas across the tropics, remains largely unresolved. Here, we tested two main hypotheses: (i) the functional diversity of lianas differs with climbing mechanism (active and passive) and (ii) the association between taxonomic diversity with contemporary climate, paleoclimate, forest structure and phylogeny differ between climbing mechanisms.LocationTropical forests.Time PeriodPresent.Major Taxa StudiedTerrestrial plants.MethodsWe assembled functional traits and the type of climbing mechanism for 702 liana species and used the World Checklist of Vascular Plants (WCVP v.2.0) to standardize species names, map geographical distribution and estimate taxonomic richness. We used kernel density n‐dimensional hypervolume to estimate the functional diversity of each type of climbing mechanism. We compared the environmental response of taxonomic richness of each type of climbing mechanism, active and passive, to the response of overall liana species richness. We assessed the magnitude and direction of the environmental response considering variables of climate, soil fertility and forest structure.ResultsWe found that active climbing exhibits a higher functional richness than passive climbing. Richness patterns of active and passive climbing mechanisms were mainly driven by contemporary climate, paleoclimate and phylogenetic relatedness. More importantly, paleoclimate was negatively associated with active climbing and positively associated with passive climbing.Main ConclusionsOur study highlights differences in functional diversity (richness, dispersion, evenness and originality) between active and passive climbing species, likely reflecting their distinct ecological strategies for resource use, stress tolerance and dispersal. Integrating taxonomic and functional diversity metrics with information about the type of climbing mechanism provides deeper insights into the ecology and response of lianas to climate change.

Environmental heterogeneity influences liana community differentiation across a Neotropical rainforest landscape.

We examined the variation in liana community composition and structure across geopedological land units to test the hypothesis that environmental heterogeneity is a driving force in liana community assembly. The study site was the Los Tuxtlas Tropical Biology Station, SE Mexico, a reserve that encompasses 640 ha of tropical rainforest. We sampled all lianas with basal diameter ≥1 cm in three 0.5-ha plots established in each of five land units (totaling 15 plots and 7.5 ha). We censused 6055 individuals and 110 species. Overall, the most speciose families were also the most abundant ones. Density and basal area of some dominant liana species differed among land units, and a permutational multivariate analysis of variance (PERMANOVA) and a non-metric multidimensional scaling ordination (NMDS) revealed differences in the presence, density, and basal area of liana species across the landscape. Liana composition and structure were highly heterogeneous among land units, suggesting that variations in soil water availability and relief are key drivers of liana community spatial differentiation. By showing that soil and topography play an important role at the landscape scale, we underscore the ecological relevance of environmental heterogeneity for liana community assembly. In the future, as our ability to assess the local environmental complexity increases, we will gain a better understanding of the liana community assembly process and their heterogeneous distribution in tropical forests.

Viability and dormancy of the Clematis vitalba aerial seed bank.

Old man's beard (Clematis vitalba L.) is a liana species that has become invasive in many areas of its introduced range. Seeds are produced in abundance and are both physiologically and morphologically dormant upon maturity. To understand the importance of seeds to its invasiveness, changes in viability and dormancy of the aerial seed bank were tracked throughout the after-ripening period and during storage. Seeds collected every second month for 2 years were subjected to germination tests. Other seeds stored in outdoor ambient conditions or in a dry, chilled state were dissected before, during, and after imbibition, as well as during incubation, to measure embryo size. Less than 72% of seeds on the mother plant were viable. Viable seeds remained completely morpho-physiologically dormant throughout autumn, even when treated with nitrate. Physiological dormancy declined in response to seasonal changes, yet morphological dormancy did not change until seeds had been exposed to appropriate germination conditions for several days. Fully dormant autumn seeds decayed at higher rates during incubation than partially or fully after-ripened seeds, which were also more germinable and less dormant. Furthermore, seeds incubated in complete darkness were more likely to decay or remain dormant than those exposed to light. This study demonstrates that fewer than three-quarters of seeds produced are viable and further decay occurs after dispersal, yet total fertility is still very high, with enormous propagule pressure from seeds alone. Viable seeds are protected with two forms of dormancy; morphological dormancy requires additional germination cues in order to break after seasonal changes break physiological dormancy.

Combining X-ray micro-CT and microscopy-based images of two lianas species to derive structural, mechanical and functional relationships

This paper presents a biomechanical study of stems of two liana species, Clematis vitalba and Vitis vinifera, investigates the mechanical performance of these two liana species and attempts to enhance the understanding of structure–function relationships. The investigation involved mechanical testing of whole plant stems, supplemented by X-ray micro-CT (X-ray computed tomography at micron voxel size) imaging and 2D microscopic images of stained cross sections of the plant stems, to derive structure–function relationships with potential for application in bioinspired composite materials. The micro-CT images were compared to the microscopic images of stained cross sections, in order to show benefits and potential drawbacks of the X-ray micro-CT method with respect to traditional methods. The high-resolution 3D imaging capacity of micro-CT is exploited to explain the structural functionality derived from the mechanical testing. A simple finite element model is developed based on the plant topology derived by the micro-CT images and proved accurate enough to model the plant’s mechanical behaviour and assess the influence of their structural differences. The two plants exhibit different to each other physical and mechanical properties (density, strength and stiffness) due to their common growth form. Anatomical cross-sectional observation and X-ray micro-CT provide complementary information. The first method allows the identification of the lignified parts, supposedly more resistant mechanically, of these structures, while the second one provides a full 3D model of the structure, admittedly less detailed but providing the spatial distribution of density contrasts supposed to be important in the mechanical properties of the plant. The proposed methodological approach opens new perspectives to better understand the mechanical behaviour of the complex structure of plants and to draw inspiration from it in structural engineering.

Identification, characterization and quantification of xanthones from Fridericia formosa leaves extract with antiviral activity

Fridericia formosa (Bureau) L.G. Lohmann (Bignonaceae) is a neotropical liana species found in the Cerrado biome in Brazil. It has been of great interest to the scientific community due to its potential as a source of new antivirals, including xanthones derived from mangiferin. In this context, the present study aimed to characterize and quantify the xanthones present in the ethanol extract of this species using high performance liquid chromatography. Additionally, the antiviral activity against Chikungunya, Zika, and Mayaro viruses was evaluated. The chromatographic analyses partially identified twenty-six xanthones, among which only fourteen had already been described in the literature. The xanthones mangiferin, 2′-O-trans-caffeoylmangiferin, and 2′-O-trans-coumaroylmangiferin, are present in higher quantities in the extract, at concentrations of 9.65%, 10.68%, and 3.41% w/w, respectively. In antiviral assays, the extract inhibited the multiplication cycle only for the Mayaro virus with a CE50 of 36.1 μg/mL. Among the isolated xanthones, 2′-O-trans-coumaroylmangiferin and 2′-O-trans-cinnamoylmangiferin inhibited the viral cytopathic effect with CE50 values of 180.6 and 149.4 μg/mL, respectively. Therefore, the extract from F. formosa leaves, which has a high content of xanthones, has antiviral potential and can be a source of new mangiferin derivatives.

Three Censuses of a Mapped Plot in Coastal California Mixed-Evergreen and Redwood Forest

Large, mapped forest research plots are important sources of data to understand spatial and temporal changes in forest communities in the context of global change. Here, we describe the data from the first three censuses of the 16-ha UC Santa Cruz Forest Ecology Research Plot, located in the Mediterranean-climate forest on the central coast of California, USA. The forest includes both mixed-evergreen forest and redwood-dominated forest and is recovering from significant logging disturbances in the early 20th century. Each woody stem with a diameter ≥ 1 cm at 1.3 m was mapped, tagged, identified, and measured, with censuses performed at ~5-year intervals. The first census included just 6 ha (previously described), and the area was then expanded to 16 ha in the second census. We describe the temporal dynamics of the forest in the original 6 ha, as well as the structure and temporal dynamics of the full 16 ha. The community includes 34 woody species, including 4 gymnosperm and 9 angiosperm tree species, 18 species of shrubs, and 3 species of lianas. The community includes eight non-native species, representing less than 0.5% of the stems. More than half the species show greater rates of mortality than recruitments, reflective of a dynamic forest community. Over a decade, the number of living woody stems has declined, but the basal area has increased, reflecting a self-thinning process.

Patterns of liana diversity and host interaction networks in selectively logged and unlogged forests of Uppangala, Western Ghats, India

AbstractLianas shape tropical forest species composition, structure, and dynamics. Increasing climate fluctuation and anthropogenic disturbances increase liana abundance. Despite the increasing number of liana studies in India, only a few have examined the distribution and association of hosts with lianas, or liana–host interaction networks to determine their functional significance and conservational value. Therefore, our objective was to fill the knowledge gap about the diversity, abundance, and network structure of liana–host interactions in response to logging disturbance in a wet evergreen forest of Uppangala in central Western Ghats, India. We sampled lianas ≥1 cm in diameter at 1.3 m from the base and their host trees in thirty 20 m × 20 m plots in selectively logged and unlogged forest management regimes. We evaluated liana–host tree interactions in logged and unlogged forests and retrieved community‐level measures (nestedness, connectance, modularity, and network specialization index) and species‐level indicators (species specialization index). Diversity and abundance of liana species were considerably greater in the selectively logged forest site. The logged forest site had compartmentalization, anti‐nestedness, and network specialization, while unlogged forests were not showing any significant network structure. Most species of lianas and hosts were peripherals, but others were structurally important (connectors, module hubs, and network hubs) in the two forest sites. Forest management regimes had distinct structurally significant species.

Floristic composition of the local family forest in Panarung Village, a subdistrict of Bentian Besar, West Kutai Regency, East Kalimantan, Indonesia

Ulin (Eusideroxylon zwageri T et B.) is a unique tree species in Kalimantan because its most durable wood and only grows in mixed lowland dipterocarp forest habitat. The purpose of this study is to examine the floristic composition, variety, and structure of the mixed ulin forest in Penarung village, subdistrict of Bentian Besar, West Kutai Regency, East Kalimantan. Each sample plot was rectangular and was 125 m by 20 m in size. For the tree stage, each sample plot was divided into subplots that measured 25 m by 20 m. Each subplot measured 2 m by 2 m for seedlings, thickets, and herbs and 5 m by 5 m for saplings The Result showed the species richness was 196 species, which consisted of 147 tree species, 16 species of lianas, 13 species of herbs, 12 species of shrubs, 5 species of ferns, 2 species of rattan and 1 species of palm. The tree stage consisted of 97 species, 70 genera, and 36 families. Species diversity (H’), showed that tree and sapling stages were high 3.82 for tree and 3.92 for sapling stages, while seedlings in moderate, with H’= 2.49. Evenness (E) in the tree stage was 0.83, while sapling and seedling were 0.87 and 0.55 respectively. This forest contained 28 species of endemic, 2 species of critically endangered (CR), 2 species endangered (EN), and 10 species of vulnerable (Vu).

Divergences in stem and leaf traits between lianas and coexisting trees in a subtropical montane forest

Abstract Patterns in functional trait variation associated with the ecological strategies of lianas and trees in subtropical montane forests remain poorly understood due to lack of trait comparisons. Here, we filled this gap by investigating trait divergence between lianas and trees with different leaf habits for 13 traits of 33 species (7 deciduous and 4 evergreen liana species, and 10 deciduous and 12 evergreen tree species) in a subtropical montane forest in southwestern China. We found that lianas had significantly larger stem xylem vessel diameter, higher theoretical hydraulic conductivity, specific leaf area, leaf nitrogen, and phosphorus concentrations, but lower leaf dry-matter content and N/P ratio than sympatric trees, indicating that lianas employ an acquisitive ecological strategy, with a more efficient stem hydraulic system and more productive leaves. In contrast to trees, lianas exhibited a larger variation in vessel diameter, with a few wide and many narrow vessels in the xylem, indicating a greater vessel dimorphism. Growth form explained 48.7% of the total trait variation, while leaf habit only explained 3.8% of trait variation, without significant interaction between growth form and leaf habit. In addition, significant stem–leaf trait relationships were only found in trees, but not in lianas, indicating decoupling of stem hydraulic function and leaf traits in subtropical lianas. These results suggest that subtropical montane lianas and trees differ strikingly in stem and leaf functional traits. Further studies are warranted to strengthen our understanding of the mechanisms underlying the strong divergence in ecological strategies between lianas and trees in subtropical forest ecosystems.

Effects of plant diversity, soil microbial diversity, and network complexity on ecosystem multifunctionality in a tropical rainforest.

Plant diversity and soil microbial diversity are important driving factors in sustaining ecosystem multifunctionality (EMF) in terrestrial ecosystems. However, little is known about the relative importance of plant diversity, soil microbial diversity, and soil microbial network complexity to EMF in tropical rainforests. This study took the tropical rainforest in Xishuangbanna, Yunnan Province, China as the research object, and quantified various ecosystem functions such as soil organic carbon stock, soil nutrient cycling, biomass production, and water regulation in the tropical rainforest to explore the relationship and effect of plant diversity, soil microbial diversity, soil microbial network complexity and EMF. Our results exhibited that EMF decreased with increasing liana species richness, soil fungal diversity, and soil fungal network complexity, which followed a trend of initially increasing and then decreasing with soil bacterial diversity while increasing with soil bacterial network complexity. Soil microbial diversity and plant diversity primarily affected soil nutrient cycling. Additionally, liana species richness had a significant negative effect on soil organic carbon stocks. The random forest model suggested that liana species richness, soil bacterial network complexity, and soil fungal network complexity indicated more relative importance in sustaining EMF. The structural equation model revealed that soil bacterial network complexity and tree species richness displayed the significantly positive effects on EMF, while liana species richness significantly affected EMF via negative pathway. We also observed that soil microbial diversity indirectly affected EMF through soil microbial network complexity. Soil bulk density had a significant and negative effect on liana species richness, thus indirectly influencing EMF. Simultaneously, we further found that liana species richness was the main indicator of sustaining EMF in a tropical rainforest, while soil bacterial diversity was the primary driving factor. Our findings provide new insight into the relationship between biodiversity and EMF in a tropical rainforest ecosystem and the relative contribution of plant and soil microibal diversity to ecosystem function with increasing global climate change.