Karst Forest Research Articles

Impacts of Lithology and Slope Position on Arbuscular Mycorrhizal Fungi Communities in a Karst Forest Soil.

The influence of lithology and slope position on arbuscular mycorrhizal fungi (AMF) communities has been explored in various ecosystems, but there is a limited understanding of these mechanisms in karst regions. This study focused on typical karst hills with contrasting lithologies, specifically dolomite and limestone. Additionally, three slope positions (upper, middle, and lower) were investigated within each hill in karst forest ecosystems. Total phosphorus (TP) content in the soil was higher in dolomite compared to limestone. Conversely, exchangeable calcium (Ca) was lower in dolomite than in limestone. Notably, the lithology, rather than the slope position, exerted a significant impact on AMF diversity and abundance and the presence of specific AMF taxa. Dolomite exhibited greater AMF richness and a higher Shannon index in comparison to limestone when not accounting for slope position. The AMF community composition differed between dolomite and limestone. For instance, without considering slope position, the relative abundance of Acaulospora, Diversispora, and Paraglomus was higher in dolomite than in limestone, while the relative abundance of Claroideoglomus displayed an opposing trend. Furthermore, a more complex interaction among AMF taxa was observed in dolomite as compared to limestone, as evidenced by an increase in the number of nodes and edges in the co-occurrence networks within the dolomite. The genera Glomus, Claroideoglomus, and Diversispora exhibited a higher number of links with each other and with other AMF taxa. The study identified TP and Ca as the primary factors determining variations in AMF diversity between dolomite and limestone. Consequently, it is imperative to consider the underlying lithology and soil conditions when addressing the restoration of degraded karst hilly areas.

Diversity and soil chemical properties jointly explained the basal area in karst forest

Diversity and soil chemical properties jointly explained the basal area in karst forest

Increasing plant species diversity suppresses free‐living N2 fixation in litter and soil of a subtropical karst forest

Abstract Free‐living N2 fixation (FNF) is an important source of bioavailable nitrogen for forests. Though increasing plant species diversity (PSD) benefits soil nitrogen accumulation, how it impacts FNF rate has not been explored. Forty‐five plots covering a PSD gradient were selected in a subtropical karst forest, southwest China. FNF rates in leaf litter and soil were measured using acetylene reduction assay calibrated with a 15N2 fixation method. Diazotrophic community, litter and soil properties were determined as well. The nifH gene abundance was not significantly altered in litter but was significantly decreased in soil by higher PSD. Diazotrophic community's Shannon diversity was significantly increased by higher PSD in both litter and soil. Increasing PSD inhibited litter FNF rate via aggravating phosphorus limitation and decreasing the relative abundance of Betaproteobacteria and Deltaproteobacteria. For the mineral soil horizon, increasing PSD suppressed FNF rate via decreasing nifH gene abundance caused by elevated N availability and lowered phosphorus and iron availability or through decreasing the relative abundance of Deltaproteobacteria but increasing that of Betaproteobacteria. Our findings, for the first time, reveal the microbial and abiotic controls on FNF in litter and soil in response to PSD, and hence benefit the prediction of nitrogen input via biological N2 fixation under changes in PSD. Read the free Plain Language Summary for this article on the Journal blog.

Forest Fires, Stakeholders’ Activities, and Economic Impact on State-Level Sustainable Forest Management

In Europe, forest fires are a serious and constant threat. They destroy forests and forest land, causing damage, financial loss, and long-lasting impacts on forest ecosystem services. There are several ways to decrease the number of forest fires, including continuous investment in fire prevention measures and the intensive implementation of adaptive sustainable forest management measures, which need additional financial resources. In many cases, forest management activities in karst forests are not implemented in a timely manner and in coordination with other stakeholders. A comprehensive study about the impact of forest fires on different economic activities (tourism and protected areas) is not currently available. In this study, the legislative framework in Croatia was analysed in relation to the fire protection activities and jurisdictions of different institutions. From data collected in the period 2013–2020, the first-age class afforestation costs and growing stock assortment value were calculated, and the non-wood forest functions were estimated. The aforementioned data were further compared to the Fire Weather Index (FWI) and Seasonal Severity Rating (SSR) of fire seasons. The total estimated damage is EUR 326,810,724.72. The research emphasises the need for the implementation of cross-sectoral forest policy measures. The state forest company should allocate more financial resources for biological forest restoration in the future. Forest management practices should implement climate-adaptable silviculture measures to preserve forest and forest land.

Elevated Mercury Deposition, Accumulation, and Migration in a Karst Forest.

The karst forest is one of the extremely sensitive and fragile ecosystems in southwest China, where the biogeochemical cycling of mercury (Hg) is largely unknown. In this study, we investigated the litterfall deposition, accumulation, and soil migration of Hg in an evergreen-deciduous broadleaf karst forest using high-resolution sampling and stable isotope techniques. Results show that elevated litterfall Hg concentrations and fluxes in spring are due to the longer lifespan of evergreen tree foliage exposed to atmospheric Hg0. The hillslope has 1-2 times higher litterfall Hg concentration compared to the low-lying land due to the elevated atmospheric Hg levels induced by topographical and physiological factors. The Hg isotopic model suggests that litterfall Hg depositions account for ∼80% of the Hg source contribution in surface soil. The spatial trend of litterfall Hg deposition cannot solely explain the trend of Hg accumulation in the surface soil. Indeed, soil erosion enhances Hg accumulation in soil of low-lying land, with soil Hg concentration up to 5-times greater than the concentration on the hillslope. The high level of soil Hg migration in the karst forest poses significant ecological risks to groundwater and downstream aquatic ecosystems.

A New Advance on the Improvement of Forest Ecosystem Functions in the Karst Desertification Control

In recent years, after the implementation of large-scale ecological restoration projects, karst areas in the South China Karst have become global “greening” hot spots. However, the biodiversity, ecosystem quality, and security patterns in karst areas are still severely affected. The reason for this is that despite the execution of karst desertification control projects, the lag mechanism of forest ecosystem functions and services is still unclear. Therefore, we analyze the progress in the research related to desertification control and the improvement of regional forest ecosystem function through a systematic literature review approach. The results show that the major landmarks achieved so far include the following aspects: based on the karst desertification control area, we have elucidated the driving factors of forest ecosystem change, discovered the ecological security pattern of landscape optimization and reconstruction, revealed the internal mechanism of forest system structure optimization and stability enhancement, overcome the technical constraints of forest water–fertilizer coupling, introduced a strategy for regulating functional traits to improve the growth and development of vegetation, proposed strategies to enhance carbon sequestration in forests and the efficiency of microbial carbon use, and created models and paths to realize the value of forest products. The key scientific issues to be addressed in the future mainly comprise the following: the effects of spatial heterogeneity on forest ecosystems, disturbances in landscape reconfiguration caused by human activities, the work mechanisms of the combination and configuration of the niche in structural optimization, the response of species configuration to the water cycle, the coupled relationship between biodiversity and soil properties, the screening and construction of the plant germplasm resource base, the functional trade-offs/synergistic mechanisms of karst forest ecosystems, the creation of policies for forest product in terms of rights, trading, and compensation, and systematic research on the extended industrial chain of forest ecosystems, its service potential, and so on.

Differences in the vegetation dynamic patterns of three tropical secondary forests in South Sulawesi, Indonesia

Abstract. Putra PS, Yamada T, Achmad A, Nasri N, Hamzah AS, Ngakan PO. 2023. Differences in the vegetation dynamic patterns of three tropical secondary forests in South Sulawesi, Indonesia. Biodiversitas 24: 5065-5073. Degraded forests experience dynamics that drive them towards stable ecological conditions as a result of the succession process. Understanding the dynamics of forests through succession is a requirement for secondary forest management activities. The purpose of this research was to uncover the dynamics of population, species composition, and dominance in three secondary tropical forest communities: (i) Karst forest, (ii) Lowland forest, and (iii) Pinus merkusii plantation forest. Permanent plots with areas tailored to the richness of each forest community were constructed, and vegetation studies were conducted annually from 2019 to 2022. The results revealed that the ten most dominant species in each plot shared only one species. The rest were exclusive to a single community. During the four years of research, 25 out of a total of 90 species (Karst), 27 out of a total of 68 species (Lowland), and 12 out of a total of 43 species (Pine) experienced dynamics in the form of an increase or decrease in population. Tree density decreased in the Karst plot and fluctuated slightly in the Lowland and Pine forest plots. Meanwhile, the basal area cover continued to increase during the 4 years of observation. Comparing age and pre-succession land use history, soil type and restoration history appear dominant in determining the forest dynamics.

Distribution pattern and factors affecting litter stocks at the slope-scale in a karst forest in subtropical China

Litter distribution significantly affects nutrient cycling, energy transfer, and various ecosystem services. However, little is known about how microtopography affects litter accumulation and distribution on the forest floor. Distribution characteristics of litter stocks at the slope-scale and their relationship with topography and rock exposure rate (RER) in a typical subtropical karst forest in China were determined by measuring the litter stock and RER of 300 grids of1 × 1 m in a 10 × 120 m square on a limestone hill. The results showed that (1) the average litter stock of karst forest was 691.54 ± 332.60 g∙m-2, among which 65.81% was undecomposed litter; (2) the spatial distribution of litter stocks was uneven with moderate variation, presenting five aggregated areas and four sparse areas on the entire slope; (3) there was a significant negative correlation between RER and litter stock (R = −0.37, P < 0.01), which increased with increasing slope gradient and slope position; and (4) the RER coupled with topography in karst areas directly affected litter accumulation via the redistribution process and indirectly affected the decomposition rate by altering the microenvironment, which reshaped the slope-scale distribution pattern of litter stocks. Our research highlights the importance of the complex slope-scale morphology of karst ecosystems in altering nutrient cycling and energy transfer by mediating litter redistribution, providing new insights into the formation of the high environmental heterogeneity in karst habitats.

How diverse are the mountain karst forests of Mexico?

Tropical forests on karstic relief (tropical karst forest) are among the most species-rich biomes. These forests play pivotal roles as global climate regulators and for human wellbeing. Their long-term conservation could be central to global climate mitigation and biodiversity conservation. In Mexico, karst landscapes occupy 20% of the total land surface and are distributed mainly in the southeast of the country, along the eastern slope, and in the Yucatan Peninsula. Within each of these areas, the following types of karst occur: coastal karst, plain karst, hill karst, and mountain karst (low, medium, high). Mountain karst cover 2.07% of Mexico's land surface and are covered by tropical rainforests, montane cloud forests, and tropical deciduous forests. These are probably one of the most diverse biomes in Mexico. However, the mountain karst forests of Mexico have received little attention, and very little is known about their diversity. Here, we evaluated the vascular plant species richness within the mountain karst forests of Mexico. We assembled the first, largest, and most comprehensive datasets of Mexican mountain karst forest species, from different public databases (CONABIO, GBIF, IBdata-UNAM), which included a critical review of all data. We compiled a list of the families, genera, and species present within the mountain karst forests of Mexico. Taxa that best characterize these forests were identified based on their spatial correlation with this biome. We explored biodiversity patterns, identifying areas with the highest species richness, endemism centers, and areas of relatively low sampling intensity. We found that within the mountain karst forests of Mexico there are representatives of 11,771 vascular plant species (253 families and 2,254 genera), ca. 50% of the Mexican flora. We identified 372 species endemic to these forests. According to preliminary IUCN red list criteria, 2,477 species are under some category of conservation risk, of which 456 (3.8%) are endangered. Most of the Mexican mountain karst forests have been extensively explored and six allopatric, species-rich areas were identified. Compared to other regions in the world, the mountain karst forests of Mexico are one of the most diverse biomes. They contain more species than some entire montane systems in Mexico such as Sierra Madre Oriental, and Sierra Madre del Sur. Also, the mountain karst forests of Mexico are most diverse than similar forests of South America and Asia, even if considering the effect of different sampling areas. The fact that mountain karst forests are embedded in areas of high biotic diversity, probably contributes to their great floristic diversity. Thus, the mountain karst forests of Mexico are an important source of diversity and shelters a large percentage of the Mexican flora.

Effects of rock lithology and soil nutrients on nitrogen and phosphorus mobility in trees in non-karst and karst forests of southwest China

The primary productivity of terrestrial plants is widely limited by nitrogen (N) and phosphorus (P), and the mobility of N and P in plants is the key to predicting plant growth and development. Non-karst and karst forests soil have different nutrient supply capacities due to the difference in soil parent material, but the effect mechanism of the two soil nutrient conditions on the N and P mobility process of trees remains unclear. In this study, forests dominated by three typical tree species, Eucalyptus maideni, Pinus yunnanensis, and Quercus franchetii were selected as the research objects in non-karst and karst areas of southwest China to investigate the effects of soil nutrient conditions on plants’ N and P foraging, transportation and resorption. The results showed that the rock lithology had significant effects on the soil nutrients, plants’ N and P foraging, transportation, and resorption. The soil total N and P concentrations, soil organic carbon concentration, and pH were higher in karst forests than those in the non-karst forests, but the green leaves N and P concentrations exhibited opposite characteristics. The root foraging potential for N and P in non-karst forests was significantly higher than that in karst forests. The N resorption efficiency of trees in karst forests was higher than that in non-karst forests, but the P resorption efficiency was lower than that in non-karst forests. The trade-offs of foraging, transportation and resorption of trees were adjusted according to changes in nutrient conditions, but the trade-offs of the three processes were not continuous in non-karst and karst forests. Compared with non-karst forests, the decreased degree of root nutrient foraging potential in karst forests was greater than the transportation factor and resorption efficiency. The slow-growing Quercus franchetii among the three typical forests showed better adaptability to foraging, transportation, and resorption of N and P in karst areas. The results revealed the response of different forests’ N and P mobility patterns of trees to different nutrient conditions in non-karst and karst areas, which was helpful to improve the prediction and mechanistic understanding of nutrient cycling in local forest ecosystems.

Seasonal diversity and distribution of decomposing macrofungi in three forest communities: why do they differ?

The diversity of macrofungal species, especially those that are not edible, receives less attention because people do not realize the importance of their ecological role. This study aimed to reveal the inter-seasonal diversity of macrofungal species in three forest communities in South Sulawesi: Karst forest, Lowland forest, and Pine forest. Field surveys were carried out twice (i.e. in the wet and dry seasons) in 25 units plots measuring 10 m x 10 m which were systematically spread in an area of approximately 1 ha in each forest community. The macrofungi found in each plot were recorded by the species name, photo, and the area of cover that measured using Crown Diameter Method to analyse the area of cover. In total there were found 130 species of macrofungi from 38 families across forest communities both in wet and dry seasons. The highest number of macrofungi species was found in the Lowland Forest (67 species), followed by Karst Forest (65 species), and the lowest was in Pine forest (42 species). Some species are specialists in specific forest communities. Given that most species of macrofungi are monophagous that specialist to an only litter of one tree species, the difference in the diversity of macrofungi among forest communities is likely related to the difference in tree species diversity among forest communities. In addition, microhabitat conditions were found in line with the diversity of macrofungal species inter-seasons and inter-forests.

A modified approach to model the hydrological effects of living moss and fallen leaves on carbonate-derived laterite in karst forests

Due to recent vegetation restoration projects in karst mountainous areas of China, the living moss and litter layer play important roles in controlling soil water dynamics in karst forests. However, the underlying mechanisms of the effects of moss and the litter layer on soil water dynamics are still controversial. To explore the underlying mechanisms, we employ the CoreKarHydro model, capturing soil water content dynamics driven by evapotranspiration and influenced by living moss and fallen leaves. This model integrates surface changes' impact on evapotranspiration, categorizing the domain into: no cover (S), moss (SM), pine needles (SP), and both (SMP). Model validation employs the MOCOM-UA method, using diverse metrics (RMSE, R2, ACC, ED, KGE and SA) against lysimeter data with 4 moss biomass levels and 3 pine needle biomass levels. The results indicated: 1) The CoreKarHydro model exhibited reliable performance in simulating the soil water content curves, with an RMSE ranging from 1.49% to 4.21% and an R2 value ranging from 0.60 to 0.77. 2) Among the factors that influenced evaporation processes, soil hydraulic properties emerged as the most sensitive parameters, whereas the properties of the moss and pine needles played a relatively lesser role. 3) The impact of moss cover on evaporation processes varied depending on the soil texture and the stage of evaporation. Moss cover reduced evaporation loss in 8 out of 12 soil textures (loamy sand, loam, silt, silt loam, sandy clay loam, silty clay loam, sandy clay, and silty clay). On the other hand, moss cover increased evaporation loss in 4 out of 12 soil textures (sand, sandy loam, clay loam, and clay). This study contributes to the understanding of the mechanisms of coupled soil-moss(litter)-hydrological processes in karst areas.

Habitat associations of woody plant species in evergreen–deciduous broadleaf karst forests in southwest China

The effects of habitat filtering on community assembly have been extensively researched, and topography has been identified as a critical factor influencing the spatial distribution of trees. In this study, a 25-ha plot was established in karst evergreen–deciduous broadleaf forests in southwestern China. Eight topographical factors were used to divide plots into four habitat types, i.e., hilltop, steep slope, gentle slope, and depression, using a multivariate regression tree. A total of 85 evergreen and deciduous tree species were recorded in these four habitats and classified into three life stages, the differentiation of which was assessed using torus-translation tests. A total of 65 species significantly positively associated with at least one habitat and 79 species significantly negatively associated with at least one habitat were identified. Most species, whether evergreen or deciduous, exhibited a positive correlation with steep slopes, whereas relatively few species were adapted to depressions. Moreover, the percentage of evergreen species positively associated with hilltops and steep slopes was higher than that of deciduous species. Both evergreen and deciduous species showed an increasing percentage of positive correlation with hilltops from the sapling stage to the mature stage. However, more evergreen species grew on steep slopes in the sapling stage, whereas deciduous species grew in the mature stage. Canonical correspondence was used to analyze the relationship between species and the eight topographical factors. Regardless of life form or life stage, results showed that species distribution was significantly affected by topography. Furthermore, the distribution of evergreen species on sapling-stage trees was found to be more influenced by topography, whereas deciduous species were more influenced by topography in the mature stage. Finally, elevation was identified as the most crucial topographical factor affecting species distribution.

Patterns in leaf traits of woody species and their environmental determinants in a humid karstic forest in southwest China

IntroductionLeaf functional traits constitute a crucial component of plant functionality, providing insights into plants’ adaptability to the environment and their regulatory capacity in complex habitats. The response of leaf traits to environmental factors at the community level has garnered significant attention. Nevertheless, an examination of the environmental factors determining the spatial distribution of leaf traits in the karst region of southwest China remains absent.MethodsIn this study, we established a 25 ha plot within a karst forest and collected leaf samples from 144 woody species. We measured 14 leaf traits, including leaf area (LA), leaf thicknes (LT), specific leaf area (SLA), leaf length to width ratio (LW), leaf tissue density (LTD), leaf carbon concentration (LC), leaf nitrogen concentration (LN), and leaf phosphorus concentration (LP), leaf potassium concentration (LK), leaf calcium concentration (LCa), leaf magnesium Concentration (LMg), leaf carbon to nitrogen ratio (C/N), leaf carbon to phosphorus ratio (C/P), and leaf nitrogen to phosphorus ratio (N/P), to investigate the spatial distribution of community-level leaf traits and the response of the leaf trait community-weighted mean (CWM) to topographic, soil, and spatial factors.ResultsResults showed that the CWM of leaf traits display different spatial patterns, first, the highest CWM values for LT, LTD, C/N, and C/P at hilltops, second, the highest CWM values for LA, SLA, LW, LC, LN, LP, and LK at depressions, and third, the highest CWM values for LCa, LMg, and N/P at slopes. The correlation analysis showed that topographic factors were more correlated with leaf trait CWM than soil factors, with elevation and slope being the strongest correlations. RDA analysis showed that topographic factors explained higher percentage of leaf trait CWM than soil factors, with the highest percentage of 19.96% being explained by elevation among topographic factors. Variance Partitioning Analysis showed that the spatial distribution of leaf traits is predominantly influenced by the combined effects of topography and spatial factors (37%-47% explained), followed by purely spatial factors (24%-36% explained).DiscussionThe results could improve our understanding of community functional traits and their influencing factors in the karst region, which will contribute to a deeper understanding of the mechanisms that shape plant communities.

Variations in soil nutrient availabilities and foliar nutrient concentrations of trees between temperate monsoon karst and non‐karst forest ecosystems on Mount Ibuki in Japan

AbstractPlants growing on karst soils, which are characterized by high pH (&gt;7.5–8.0) and low phosphorus availability, often exhibit phosphorus deficiency. However, little is known about the soil nutrient availabilities and foliar nutrient concentrations of trees in karst ecosystems with lower soil pH (&lt;7.0). In this study, we analyzed soil properties and nutrient concentrations of leaf litter from two secondary forests in the Asian monsoon temperate region of Japan, one on karst (limestone) soil and the other on non‐karst (sandstone) soil. We also compared the live leaf nutrient concentrations of four dominant tree species (Carpinus tschonoskii, Cornus macrophylla, Neolitsea sericea, and Quercus variabilis) found in both sites. The karst soil had a higher pH (6.5) than the non‐karst soil (5.6), as well as higher phosphorus concentrations and calcium availability, but lower potassium availability. The phosphorus concentrations measured using Truog ([NH4]2SO4) and Olsen (NaHCO3) extraction methods were both higher in the karst soil. The availabilities of ammonium and nitrate in the soil did not differ significantly between the sites. The concentrations of calcium, potassium, and phosphorus in the live leaves and leaf litter reflected their availability in the soil, and the litter nitrogen concentration was higher in the karst forest. Overall, this karst soil with a relatively low pH (6.5) was rich in phosphorus but poor in potassium. Karst soil may provide a large quantity of phosphorus for trees at low pH. Future research should investigate the change in phosphorus availability of karst soils at different degrees of weathering.

Bacterial and Fungal Community Profiling of Karst Ecosystem in Basey, Samar, Philippines Using Shotgun Metagenomic Approach

The Philippines has an abundance of karst or forest over limestone landscapes, but only a small percentage of them have been studied and protected. Although the flora and fauna of karst forests are diverse and unique, little is known about the microflora that inhabits this ecosystem. The taxonomic and functional composition of bacteria and fungi in soil samples from three locations within three karst forest zones in Basey, Samar, Philippines were analyzed using Illumina shotgun metagenome sequencing. Proteobacteria and Actinobacteria bacterial sequences were most prevalent in the karst soil, followed by those of the Firmicutes, Acidobacteria, Chloroflexi, Planctomycetes, Cyanobacteria, Verrumicrobia, Bacteriodetes, and Deinococcus-Thermus. The most abundant fungal sequences belonged to Ascomycota, followed by Basidiomycota. An average of 33 million predicted protein features was detected across all sites. Enzyme pathways for nitrogen and sulfur metabolism, and several carbon fixation pathways, appeared nearly complete. To our knowledge, this is the first report to provide baseline information on the microbial community and their possible roles in karst forest ecosystem health in the Philippines, which may lead to identifying new microbes with specialized metabolism and promoting biodiversity conservation of karst forests in the Philippines. Furthermore, correlation analysis with plant diversity will reveal plant-microbe interaction leading to the understanding of the adaptation, abundance, survival, and diversity of microorganisms and plants.

Effects of Tiankeng topography on ecological strategy of karst evergreen and deciduous broad-leaved mixed forest

Tiankeng negative topography is a magnificent landscape located in karst evergreen and deciduous broad-leaved mixed forests. It has garnered increasing attention due to its geomorphological features, natural species refuge, and biodiversity conservation. Given its unique nature, it is likely that ecological strategy for resource allocation, key factors influencing species strategies, and underlying coexistence mechanisms of species in this habitat may differ from those found in general karst forests. Thus, we established three types of forest plots (The inside of Tiankeng forest, the fringe of Tiankeng forest and nearby typical karst forest) on two contrasting topographies (Tiankeng and mountain) and measured plant leaf functional traits and soil characteristics in a karst evergreen and deciduous broad-leaved mixed forest of southwest China. Based on measurements of leaf area, leaf dry matter content and specific leaf area in the “StrateFy” tool, we compared the effects of variations in ecological strategy by using Grime’s competitor (C), stress-tolerator (S), and ruderal (R) theory. The results showed that unique species in the inside of Tiankeng forests were 10.87% −17.98% higher than those in the nearby karst forests, and the soil phosphorus in the inside of Tiankeng forests was significantly higher than those in the nearby karst forests (P < 0.05). CSR strategies components were significantly different in the three forests. The component C and R in the inside of Tiankeng forests were higher than that in fringe of Tiankeng forests and nearby karst forests, indicating that the inside of Tiankeng forests can recruit more C- and R- selected species from the nearby forests. Furthermore, Tiankeng negative topography affected the distribution of species CSR strategy by altering soil characteristics, and the soil total phosphorus was the principal driver of species ecological strategy in the inside of Tiankeng forests. Our findings highlight the naturalness and specificity of Tiankeng species in evergreen and deciduous broad-leaved mixed forests, and differentiation in ecological strategy maybe one mechanism facilitates species coexistence. We suggest that the conservation of Tiankeng should not only focus on in-situ preservation of biodiversity but also consider the role of nearby karst forests in promoting sustainable development of Tiankeng.

The Role of Bedrock Geochemistry and Climate in Soil Organic Matter Stability in Subtropical Karst Forests of Southwest China

The stability of soil organic matter (SOM) plays a critical role in soil carbon (C) dynamics under global warming. However, the factors influencing SOM stability, particularly the significance of bedrock geochemistry and its hierarchical relationship with climate and soil properties, remain poorly understood. To address this gap, we conducted a study along a large climatic gradient (Δtemperature &gt; 9 °C) in the subtropical karst forests of southwest China, quantifying SOM stability using thermal analysis and investigating the contributions of bedrock geochemistry, climate, and soil properties. Our results showed that SOM stability was positively correlated with mineral-associated organic C (MAOC) rather than particulate organic C. Hierarchical partitioning analysis further demonstrated that bedrock geochemistry was the predominant contributor to SOM stability variance, accounting for 23.7%. Following this, soil minerals contributed to 21.1%–22.6% of the variance, the mean annual temperature to 20.3%, and microbial biomass C to 17.2%. In particular, bedrock geochemistry—specifically the presence of calcium-rich bedrock—was found to enhance SOM stability by promoting the accumulation of exchangeable calcium and calcium carbonate in soils. Additionally, high temperature improved SOM stability by increasing the content and proportion of MAOC and soil pH. These results highlight the fundamental role of bedrock geochemistry in controlling SOM stability and emphasize the importance of considering hierarchical relationships among bedrock–soil–climate interactions for evaluating soil C dynamics.

The genetic structure and demographic history of Zabelia tyaihyonii, endemic to Korean limestone karst forests, based on genome‐wide SNP markers

AbstractSimilar to the global phenomenon, many plant species endemic to Korean limestone karst forests are at risk of extinction due to human intervention. Zabelia tyaihyonii is a familiar shrub, called “Hardy abelia” and “Fragrant abelia” growing in the karst forests of Korea, where it is one of the most threatened species. We investigated the genetic structure and demographic history of Z. tyaihyonii, which allow us to develop appropriate conservation and management strategies. The genetic structure was evaluated using a total of 187 samples from 14 populations, covering the entire distribution of Z. tyaihyonii in South Korea. We utilized 254 and 1753 SNP loci obtained via MIG‐seq (Multiplexed ISSR Genotyping by sequencing) for structure and demographic analyses, respectively. The population demographic modeling was performed with site frequency spectrum. To gain further historical insights, we also employed ENM (Ecological Niche Modeling). We found two distinct clusters (CLI and CLII) of ancient origin (ca. 490 ka). Despite CLII experiencing a more severe bottleneck, both clusters showed similar levels of genetic diversity, indicating mutual historical gene flow. Their historical distribution range seems to have changed very little. We proposed a historical distribution scenario for Z. tyaihyonii, taking into account its intrinsic factors, and emphasized a more complex response to Quaternary climate change beyond simple allopatric speciation models. These findings provide valuable insights for conservation and management strategies for Z. tyaihyonii.

The macrofungal diversity and its potential from the karst forest of Kalipoh Village, Kebumen District, Indonesia

Abstract. Armadhan WS, Sari SP, Aji MYMB, Permatasari DP, Amalia BW, Berlin GE, Aszar AS, Indrawan M, Pradhan P, Setyawan AD. 2023. The macrofungal diversity and its potential from the karst forest of Kalipoh Village, Kebumen District, Indonesia. Intl J Trop Drylands 7: 98-105. Indonesia is one of the world's most biodiverse countries, with fungi being one of its most diverse groups of organisms. Many fungi species have been identified and have potential benefits for both living things and the environment. Kalipoh Village Forest, located in the karst area of Ayah Sub-district, Kebumen District, Central Java, Indonesia, offers suitable environmental conditions that provide habitat for various species of fungi. The objective of this study was to determine the diversity and potential use of macrofungi in Kalipoh Village Forest. Data collection was carried out using the survey method, where every encountered fungus was observed and its cap, gills, stalk, color, odor, substrate, and growth habits were recorded. Macrofungal diversity was calculated using the Shannon-Wiener Diversity Index, Simpson’s Diversity Index, Richness Index, and Evenness Index Formula. The exploration results obtained 34 species of macrofungi from 22 genera and 18 families, with most of the species found on weathered logs and leaf litter. Two genera, namely Marasmius and Marasmiellus, were quite common. Based on the index value calculation, the diversity of macrofungi in this area was in the medium category (H'=2.695). It had a high index of richness (R=5.252) and evenness (E=0.764). The high evenness of the species indicates lower dominance, which can also be observed from the results of the high Simpson’s Diversity Index value (0.910). A total of 24 species of macrofungi were known to have the potential as food and medicine.