Forest Types Research Articles

Shedding light on the diversity of epiphytic mosses in some Mexican forests

Background: Epiphytic mosses are one of the most common groups in forest environments but among the most neglected by researchers in Mexico. Questions: What is the epiphytic mosses diversity, measured in richness, turnover, and community composition in Mexican forests? Species of study: Epiphytic mosses. Study site and years: Humid mountain forest, pine-oak and tropical evergreen forests. Study period: 2015 to 2021. Methods: Through a literature review and field work we compiled data on epiphytic mosses in three forest types in Mexico. We assessed the data using alpha and beta diversity analysis, indicator species, and community composition. Additionally, we explored the influence of elevation and forest type on the observed diversity patterns. Results: We report a richness of 147 species of epiphytic mosses across three types of Mexican forests. The humid mountain forest was the best sampled forest with the highest moss species richness. Although species richness is different for the forests studied, species turnover is similar among them. We demonstrated that elevation and forest type are highly correlated with species richness of epiphytic mosses. Conclusions: The epiphytic mosses studied here collectively represent over 15 % of the moss richness of Mexico. Forest type and elevation seem to be the drivers of this widely distributed richness. Finally, we call for more in-depth studies of the forests presented here, as well as those in other latitudes including variables such as humidity and host traits, to provide a more complete picture of an overlooked Mexican flora.

Mapping fine-scale carbon sequestration benefits and landscape spatial drivers of urban parks using high-resolution UAV data

Urban parks offer dual ecological benefits by increasing carbon sinks and reducing carbon emissions and are considered an important natural strategy for cities to achieve “double carbon” goals. However, rapid, efficient, and accurate quantification of the carbon sequestration benefits of urban parks poses a significant challenge. To address this, we utilized unmanned aerial vehicle (UAV) multispectral data to construct large-area, high-resolution models of urban park carbon sequestration benefits, replacing traditional, time-consuming, and laborious large-scale field surveys. Additionally, we explored the relationship between urban park landscape patterns and the benefits of carbon sequestration. First, we used data from 12 tree species to calculate the carbon storage based on tree species and compared these results with those calculated based on forest type. Second, three prediction models were constructed using multispectral vegetation index only, texture features only, and a combination of both, in conjunction with gradient boosting decision Trees (GBDT), random forest (RF), and backpropagation (BP) neural network to generate carbon sequestration benefit maps for the entire park. These maps allowed us to determine how variations in urban park landscape structures affect carbon stocks. The results show that UAV multispectral imagery provides a fast and accurate method for measuring the carbon sequestration benefits of urban parks and offers an alternative method for generating carbon sequestration benefit maps. This research reveals the benefits of urban park carbon sequestration and explores the spatial patterns within landscapes. The findings are of great significance for guiding the estimation of urban carbon sequestration benefits and achieving carbon neutrality.

Smoke Emissions and Buoyant Plumes above Prescribed Burns in the Pinelands National Reserve, New Jersey

Prescribed burning is a cost-effective method for reducing hazardous fuels in pine- and oak-dominated forests, but smoke emissions contribute to atmospheric pollutant loads, and the potential exists for exceeding federal air quality standards designed to protect human health. Fire behavior during prescribed burns influences above-canopy sensible heat flux and turbulent kinetic energy (TKE) in buoyant plumes, affecting the lofting and dispersion of smoke. A more comprehensive understanding of how enhanced energy fluxes and turbulence are related during the passage of flame fronts could improve efforts to mitigate the impacts of smoke emissions. Pre- and post-fire fuel loading measurements taken during 48 operational prescribed burns were used to estimate the combustion completeness factors (CC) and emissions of fine particulates (PM2.5), carbon dioxide (CO2), and carbon monoxide (CO) in pine- and oak-dominated stands in the Pinelands National Reserve of southern New Jersey. During 11 of the prescribed burns, sensible heat flux and turbulence statistics were measured by tower networks above the forest canopy. Fire behavior when fire fronts passed the towers ranged from low-intensity backing fires to high-intensity head fires with some crown torching. Consumption of forest-floor and understory vegetation was a near-linear function of pre-burn loading, and combustion of fine litter on the forest floor was the predominant source of emissions, even during head fires with some crowning activity. Tower measurements indicated that above-canopy sensible heat flux and TKE calculated at 1 min intervals during the passage of fire fronts were strongly influenced by fire behavior. Low-intensity backing fires, regardless of forest type, had weaker enhancement of above-canopy air temperature, vertical and horizontal wind velocities, sensible heat fluxes, and TKE compared to higher-intensity head and flanking fires. Sensible heat flux and TKE in buoyant plumes were unrelated during low-intensity burns but more tightly coupled during higher-intensity burns. The weak coupling during low-intensity backing fires resulted in reduced rates of smoke transport and dispersion, and likely in more prolonged periods of elevated surface concentrations. This research facilitates more accurate estimates of PM2.5, CO, and CO2 emissions from prescribed burns in the Pinelands, and it provides a better understanding of the relationships among fire behavior, sensible heat fluxes and turbulence, and smoke dispersion in pine- and oak-dominated forests.

Integrating remotely sensed imagery in a forest gap model to study North American boreal forests in a changing world

Abstract Boreal forests of Alaska and Western Canada are experiencing rapid climate change characterized by higher temperatures, more extreme droughts, and changing disturbance regimes, resulting in forest mortality and composition changes. Mechanistic models are increasingly important for predicting future forest trends as the region experiences novel environmental change. Previously, many process-based models have generated starting conditions by ‘spinning up’ to equilibrium. However, setting appropriate initial conditions remains a persistent challenge in using mechanistic forest models, where stochastic events and latent parameters governing tree establishment have long-lasting impacts on simulation outcomes. Recent advances in remote sensing analysis provide information that can help address this issue. We updated an individual-based gap model, the University of Virginia Forest Model Enhanced (UVAFME), to include initial conditions derived from aerial and satellite imagery at two locations. Following these updates, material legacies (e.g., trees, seed banks, soil organic layer) allowed new forest types to persist in UVAFME simulations, landscape-level forest heterogeneity increased, and forest-wide biomass estimates increased. At both study sites, initialization from remotely sensed data had a strong impact on forest cover and volume. Climate change impacts were simulated decades earlier than when the model was ‘spun up'. In Alaska’s Tanana Valley State Forest, warmer climate scenarios drove deciduous expansion, increased drought stress, and resulted in a 28% decrease in overall biomass by 2100 between historical and high emissions climate scenarios. At a lowland site in Northern British Columbia, lodgepole pine (Pinus contorta) remained dominant and became more productive with exogenous climate forcing as temperature, nutrient, and flooding limitations decreased. These case studies demonstrate a new framework for forest modeling and emphasize the advantages of integrating remotely sensed data with mechanistic models, thereby laying groundwork for future research that explores near-term impacts of non-stationary ecological change.

Changes in Spatiotemporal Pattern and Its Driving Factors of Suburban Forest Defoliating Pest Disasters

Forest defoliating pests are significant global forest disturbance agents, posing substantial threats to forest ecosystems. However, previous studies have lacked systematic analyses of the continuous spatiotemporal distribution characteristics over a complete 3–5 year disaster cycle based on remote sensing data. This study focuses on the Dendrolimus superans outbreak in the Changbai Mountain region of northeastern China. Utilizing leaf area index (LAI) data derived from Sentinel-2A satellite images, we analyze the extent and dynamic changes of forest defoliation. We comprehensively examine the spatiotemporal patterns of forest defoliating pest disasters and their development trends across different forest types. Using the geographical detector method, we quantify the main influencing factors and their interactions, revealing the differential impacts of various factors during different growth stages of the pests. The results show that in the early stage of the Dendrolimus superans outbreak, the affected area is extensive but with mild severity, with newly affected areas being 23 times larger than during non-outbreak periods. In the pre-hibernation stage, the affected areas are smaller but more severe, with a cumulative area reaching up to 8213 hectares. The spatial diffusion characteristics of the outbreak follow a sequential pattern across forest types: Larix olgensis, Pinus sylvestris var. mongolica, Picea koraiensis, and Pinus koraiensis. The most significant influencing factor during the pest development phase was the relative humidity of the year preceding the outbreak, with a q-value of 0.27. During the mitigation phase, summer precipitation was the most influential factor, with a q-value of 0.12. The combined effect of humidity and the low temperatures of 2020 had the most significant impact on both the development and mitigation stages of the outbreak. This study’s methodology achieves a high-precision quantitative inversion of long-term disaster spatial characteristics, providing new perspectives and tools for real-time monitoring and differentiated control of forest pest infestations.

A global analysis of the effects of forest thinning on soil N stocks and dynamics

Forest thinning is a critical management measure for changing the forest community structure and improving the soil microclimate and nitrogen (N) cycle. However, differences in forest types, thinning intensity, recovery time, and climate conditions make the accumulation of soil N under forest thinning uncertain; especially the soil N accumulation rate is still lacking. This study systematically discusses the effects of forest thinning on the rate of soil N stock change (RNC) and analyzes the relationship between the RNC and the rate of soil carbon (C) stock change (RCC) by synthesizing 387 global data points. Forest thinning significantly increased the soil N stock, with the RNC being +0.07 Mg/ha yr−1. The RNCs in coniferous and mixed forests (+0.07 and +0.09 Mg/ha yr−1, respectively) were higher than that in broadleaf forest (−0.03 Mg/ha yr−1). Heavy forest thinning inhibited soil N accumulation; however, light forest thinning and long-term recovery were more conducive to improving it. The RNC decreased with increasing precipitation and temperature under forest thinning. Additionally, the RNC was positively correlated with the RCC. Overall, heavy forest thinning decreases the soil N accumulation rate in the global forest ecosystem; conversely, long-term recovery increases it. Reducing the forest thinning intensity and extending the recovery time can accelerate soil N accumulation and thus reduce greenhouse gas emissions.

Diversity of ethnomycological knowledge and mushroom foraging culture in a small nation: case of Lithuania

BackgroundEven in mycophilic nations, mushroom foraging and use traditions may vary from region to region, making it part of cultural diversity and a source of traditional knowledge even in modern and changing societies. The main objective of our study was to investigate mushroom foraging and use traditions in major ethno-regions of Lithuania, to record and analyse whether and how biogeographical and ethno-cultural features influence these traditions, what is their biocultural significance, and whether they persist in the face of societal and environmental change.MethodsThe study conducted a survey among 106 respondents from eleven administrative units of Lithuania, representing four ethno-regions (Žemaitija, Suvalkija, Dzūkija and Aukštaitija, the latter divided into North and East). The age of the respondents ranged from 32 to 97 years (mean 70 years, median 68 years). Each respondent was asked six questions about mushroom species and mushroom foraging. The interviews were accompanied by 50 photographs of different mushroom species. The similarity between mushroom foragers' preferences in ethno-regions and the sets of mushroom species used for food and medicine was tested using cluster analysis. Clustering was carried out using Sørensen distances and the method of cluster mean linkage method.ResultsThe number of mushroom species recognised per respondent was quite similar, with the lowest number of mushroom species recognised in Žemaitija and the highest in Eastern Aukštaitija. Species of no economic or other importance were not well recognised in any of the regions. The number of names applied to mushroom species varied from region to region and did not coincide with the popularity of mushrooms among mushroom pickers. The number of mushroom species used for food was also similar between regions, except for Dzūkija, which had the lowest number of species collected. Nine mushroom species were identified by respondents as medicinal mushrooms, the most popular being Amanita muscaria and Inonotus obliquus. When analysing the similarity of mushroom species collected for food and medicine, it was found that ethno-regions clustered into three distinct groups. Two groups depended on the prevailing forest types, while Žemaitija formed a separate cluster defined only by local traditions.ConclusionsThe work represents the largest study of ethnomycological tradition in Lithuania, covering major ethno-regions. We have found that ethnomycological knowledge and tradition are not influenced by any long-term historical events, ethnicity or religion, but rather by the prevailing forest types and regional ethno-culture. Knowledge of edible mushrooms is considered to be inherited from the older generation and is conservative regarding the changes in the set of species consumed and mushroom-related gastronomy. This is also reflected in the safety of mushroom consumption, as mushroom poisoning was very rare among the respondents. Economically insignificant mushrooms are not distinguished and overlooked by traditional mushroom pickers who are not a good source of information on rare or otherwise noteworthy species. However, from a biocultural point of view, mushrooms and mushroom-related traditions remain important for linguistic diversity, traditional knowledge systems and their transmission.

Forest floor nematode communities and associated tree canopies: Is there an ecological linkage?

We searched for patterns supporting the hypothesis of compositional and functional linkage between forest floor nematode communities and dominant tree canopies, while controlling for some relevant soil and climate variables. Twenty-one forest sampling sites scattered throughout the South-Eastern Carpathian basin were selected under spruce, beech, and hornbeam-oak canopies. The relative contribution of forest canopy type to nematode assemblage differentiation was estimated through nematode taxonomic composition and feeding guild structure. The forest canopy type had a significant effect on nematode taxon/feeding guild composition and diversity at stand level. Several (diagnostic) nematode taxa and feeding guilds were positively associated with and accurately predicted the forest canopy types considered. Apart from the herbivorous nematodes, all the other trophic guilds were significantly related, in terms of their relative abundance, to the forest canopy type. Both nematode taxonomic and trophic diversity were significantly higher under beech canopy compared with its two counterparts. The highest total nematode beta diversity, either taxonomic or trophic, was attained between hornbeam-oak and spruce canopies. Nematode taxonomic and trophic beta diversity between forest canopy types were largely determined by taxon replacement and respectively, by a nested trophic structure. Overall, four concordant and two discordant patterns were revealed between nematode taxon and feeding guild composition with respect to overlying forest canopy, all underpinning the addressed ecological linkage. The present results bring evidence regarding the important contribution of the forest canopy, along with climatic variables, in driving the taxonomic and functional composition/diversity of nematode communities from the soil organic horizon.

Mangrove forest ecological function is influenced by the environmental settings and the benthic fauna composition

Benthic communities perform many important roles within mangrove ecosystems and are responsible for facilitating many of the functions attributed to mangrove forests. For instance, they are instrumental in mediating mangrove system productivity, and provide crucial food for juvenile nekton. Despite their importance, very few studies have investigated the benthic community of mangrove forests, and among those the results are inconsistent. This variability manifests in strong location effects, with low organism density and species richness in Indo-Pacific mangroves, compared to West Atlantic sites. These regional difference are confounded by differences in within-region environmental settings (e.g. rainfall, tidal range, spatial location along the coastal mosaic), and this complicates the development of a clear understanding of underlying consistencies. To assess the influence of contrasting environmental influences on the benthic community of mangrove forests we studied the benthic community of Rhizophora stylosa forests at two coastal estuaries and along the shores of two islands within a 75 km radius. The results showed that the community composition differed among settings, with several taxa only occurring at one of the two forests type. Furthermore, Peracarida, a common prey found in the gut of juvenile fish, was only found through the island forests, but never observed within the estuarine forests. This indicates that environmental setting can play a key role in determining the nature of mangrove benthic assemblages and their potential ecological roles. Consequently, caution is required when attributing the ecological roles of mangrove forests without accounting for changes in settings. Additionally, we only investigated a single mangrove species within the same climatic region, meaning that even greater variability is likely when the full range of mangrove types, conditions and areas are assessed. Understanding this variation is important because it implies that mangrove forest restoration projects are unlikely to achieve their desired outcomes unless setting-specific conditions are understood and taken into account.

Causes of general sanitary impact of combinations of dark coniferous trees and dynamics of forest assessment indicators according to forest types

Causes of general sanitary impact of combinations of dark coniferous trees and dynamics of forest assessment indicators according to forest types

Exploring botanical varieties in alpine landscape of Himalayas: A study of vegetation and species composition in Madhmaheshwar Valley, Western Himalaya, India

Alpine meadows emerged as the hallmark vegetation type, embodying the essence of botanical richness. In this research endeavor, the focus was on exploring the intricate tapestry of alpine flora nestled within the Madhmaheshwar Valley, spanning elevations ranging from 3200 to 4950 meters above sea level. This comprehensive study yielded a trove of botanical insights, documenting an impressive assemblage of 462 distinct plant species. These species were carefully cataloged across 237 genera, encompassing a rich diversity represented by 61 distinct families. In the study area, the family Asteraceae was the dominant family with 58 species and 30 genera followed by Rosaceae with 33 species and 16 genera, and Ranunculaceae with 27 species across 15 genera. Among the genera Carex L., with 10 species, was the dominant, followed by Saxifraga Tourn. ex L., Gentiana Tourn. ex L., Pedicularis L., and Primula L. followed closely behind with nine species each. Additionally, Rhodiola L., Bistorta (L.) Scop., and Epilobium Dill. ex L. displayed their vitality with seven species each. The study used meticulous research methodology to categorize forest types based on floral diversity and altitude distribution. Rigorous verification processes ensured the reliability of findings, with specimens identified using up-to-date references and cross-referenced with authentic herbarium samples. Fieldwork occurred between early May and late October, aligning with seasonal accessibility due to heavy snowfall the rest of the year. Alpine meadows and scrubs dominated the study area, highlighting their resilience. Alpine plants showcased various adaptive morphologies, such as cushion-forming and mat-forming structures, with thick cuticles defending against desiccation. Despite harsh conditions, these plants displayed modified structures enabling growth and blossoming. Many were highly specialized, emphasizing unique adaptations to their habitats.

The importance of different forest management systems for people’s dietary quality in Tanzania

ContextA large body of literature has shown that forests provide nutritious foods in many low- and middle-income countries. Yet, there is limited evidence on the contributions from different types of forest and tree systems.ObjectivesHere, we focus on individual trees and smaller forest patches outside established forest reserves as well as different forest management systems.MethodsWe do so by combining novel high-resolution data on tree cover with 24-h dietary recall surveys from 465 women in Tanzania.ResultsWe show that people with more unclassified tree cover (i.e., individual trees and small forest patches) in their nearby surroundings have more adequate protein, iron, zinc, and vitamin A intakes. We also find that having a nearby forest under Participatory Forest Management (PFM) system is associated with higher adequacy levels of energy, iron, zinc and vitamin A. By contrast, tree cover within other types of forest (e.g., Government Forest Reserves and Government Forest Plantations) is not positively associated with people’s dietary quality.ConclusionsOur key finding is that having individual trees, smaller forest patches and/or forest under PFM in close proximity is more beneficial for people’s diets than other types of established forests. Our results highlight the nutritional importance of trees outside established forests and question the often-assumed benefits of forests if these are made inaccessible by social barriers (e.g., legislation). Finally, our results emphasize the need to distinguish between different forest management systems when studying forest-diet linkages.

Tree diversity drives understory carbon storage rather than overstory carbon storage across forest types

Although numerous studies have proposed explanations for the specific and relative effects of stand structure, plant diversity, and environmental conditions on carbon (C) storage in forest ecosystems, understanding how these factors collectively affect C storage in different community layers (trees, shrubs, and herbs) and forest types (mixed, broad-leaved (E), broad-leaved (M), and coniferous forest) continues to pose challenges. To address this, we used structural equation models to quantify the influence of biotic factors (mean DBH, mean height, maximum height, stem density, and basal area) and abiotic factors (elevation and canopy openness), as well as metrics of species diversity (Shannon–Wiener index, Simpson index, and Pielou’s evenness) in various forest types. Our analysis revealed the critical roles of forest types and elevation in explaining a substantial portion of variability in C storage in the overstory layer, with a moderate influence of stand factors (mean DBH and basal area) and a slightly negative impact of tree species diversity (Shannon–Wiener index). Notably, forest height emerged as the primary predictor of C storage in the herb layer. Regression relationships further highlighted the significant contribution of tree species diversity to mean height, understory C storage, and branch biomass within the forest ecosystem. Our insights into tree species diversity, derived from structural equation modeling of C storage in the overstory, suggest that the effects of tree species diversity may be influenced by stem biomass in statistical reasoning within temperate forests. Further research should also integrate tree species diversity with tree components biomass, forest mean height, understory C, and canopy openness to understand complex relationships and maintain healthy and sustainable ecosystems in the face of global climate challenges.

Avian diversity in river levee forest: the effect of microscale heterogeneity

Introduction: Levee forests exhibit a vertical stratification that may contribute to structural complexity allowing a great diversity of birds to thrive on the islands. In deltaic ecosystems there is scarce or no data to prove it. Objectives: To assess variations in the composition of the bird community within levee forests. Methods: Two areas of protected wetlands belonging to the Paraná River Delta in Argentina were sampled for three years. A comparative analysis of richness, abundance, and diversity was performed in different levee forests using the point count method. Results: Three distinct types of levee forests -open, intermediate, and closed- were identified based on the structure of their vegetation, hosting a total of 85 bird species. Variation in avian community structure among forest types revealed greater diversity in open forests during winter (3.26 ± 0.13, P < 0.01) and spring (3.58 ± 0.05, P < 0.01), and greater richness in autumn (35.33 ± 3.01, P < 0.01). The closed forests exhibited increased diversity during autumn (3.16 ± 0.13, P < 0.05) and summer (3.24 ± 0.06, P < 0.05), along with elevated abundance in autumn (114 ± 13.70, P < 0.05) and richness in spring (39.17 ± 4.71, P = 0.01). Due to the evolutionary history between sites, significant variation was observed in the most recently created national park, influencing abundance in winter (141 ± 22.06, P < 0.01) and spring (176 ± 12.83, P < 0.01), as well as diversity in winter (3.25 ± 0.10, P < 0.01) and spring (3.50 ± 0.10, P < 0.01). Conclusions: The microhabitat in the different levee forests allows the birds to organize differently. Focusing on microspatial dynamics is key to a deep understanding of the biological processes within subtropical islands and to plan conservation strategies and demonstrate the transition of a recovering riparian forest towards its natural state, where the pulse of the river and the effect of seasonality do not stop operating.

A potential model of national forest co-management: History of aspen management on the Leech Lake Reservation and Chippewa National Forest in Minnesota

Aspen exists as the most abundant and industrially important forest type in contemporary Minnesota. Historically, the species was seen as economically undesirable yet saw prolific increases in abundance due to pine harvest and fire. The Leech Lake Reservation exists as a unique case study of tribal-U.S. Forest Service co-management, with 90 % of reservation land within Chippewa National Forest boundaries. This large geographical intersection was created by a series of American Indian law policies and makes the relationship between the Chippewa National Forest and the Leech Lake Band of Ojibwe unique within the USDA National Forest System. Comparison of pre-reservation and more modern forest/land cover types within the modern-day boundaries of the Leech Lake Reservation were conducted alongside investigation of historical management authority documentation of Chippewa National Forest and Leech Lake Band of Ojibwe cooperation and broader historical management of aspen in Minnesota. Results suggest historical power dynamics between the Chippewa National Forest and Leech Lake Band of Ojibwe influenced decreasing pine and increasing aspen on the Leech Lake Reservation. However, the modern relationship between the Chippewa National Forest and the Leech Lake Band of Ojibwe shows the potential for successful co-management within the shared goals of aspen management.

Trait-based community assembly and functional strategies across three subtropical karst forests, Southwestern China.

Variations in community-level plant functional traits are widely used to elucidate vegetation adaptation strategies across different environmental gradients. Moreover, studying functional variation among different forest types aids in understanding the mechanisms by which environmental factors and functional strategies shift community structure. Based on five plant functional traits, including four leaf and one wood trait, for 150 woody species, we analyzed shifts in the community-weighted mean trait values across three forest types in a karst forest landscape: deciduous, mixed, and evergreen forests. We also assessed the relative contributions of stochastic processes, environmental filtering, and niche differentiation to drive community structure using a trait-based null model approach. We found marked changes in functional strategy, from resource acquisition on dry, fertile soil plots in deciduous forests to resource conservation on moist, infertile soil conditions in evergreen forests. The trait-based null model showed strong evidence of environmental filtering and convergent patterns in traits across three forest types, as well as low niche differentiation in most functional traits. Some evidence of overdispersion of LDMC and LT occurred to partially support the recent theory of Scheffer and Van Nes that competition could result in a clumped pattern of species along a niche axis. Our findings suggest a change in environmental gradient from deciduous to evergreen forest, together with a shift from acquisitive to conservative traits. Environmental filtering, stochastic processes, niche differentiation, and overdispersion mechanisms together drive community assembly in karst forest landscapes. These findings will contribute to a deeper understanding of the changes in functional traits among karst plants and their adaptive strategies, with important implications for understanding other community assemblies in subtropical forest systems.

Labile Fraction of Organic Carbon in Soils from Natural and Plantation Forests of Tropical China

Labile organic carbon (LOC) is a key driver of forest ecosystem function and may mitigate global climate change through carbon sequestration. To explore the accumulation of LOC in tropical forest soils, we sampled from both planted and natural forests in Hainan Province, the southernmost province of China. We analyzed the concentrations of total organic carbon (TOC) and LOC and characterized various physicochemical properties such as pH and soil texture to understand their inter-relationships in tropical natural and plantation forests. Although the TOC concentration was higher in plantation forests (88.61 g/kg) than in natural forests (68.73 g/kg), the LOC concentration was higher in natural forests (5.12 mg/g) than in plantation forests (4.07 mg/g). Over a depth range of 0–50 cm from the surface, both forest types showed decreasing TOC and LOC concentrations with increasing soil depth, indicating surface aggregation. The soil is slightly acidic and primarily composed of sand particles. Correlation analysis showed a highly significant negative correlation between LOC concentration and soil pH in both forest types (p < 0.01). Soil LOC was positively correlated with soil clay and silt particles and negatively correlated with sand particles. This study provides valuable insights into soil carbon sequestration in tropical rainforest ecosystems in both plantation and natural tropical forests.

Light quality and spatial variability influences on seedling regeneration in Hawaiian lowland wet forests

Abstract Tropical forest understories tend to be light‐limited. The red‐to‐far‐red ratio (R:FR) is a useful and reliable index of light quality and its spatial variability can influence competition between native and non‐native seedlings. While per cent light transmittance has been quantified in some Hawaiian lowland wet forests (HLWF), no information exists on how the spatial distribution of understorey light varies in relation to species invasion, or if patterns of seedling regeneration and light are linked. We measured the R:FR of light in the understorey to assess light quality in three HLWF forest types: native‐dominated, partially invaded and Psidium cattleyanum‐ (strawberry guava) dominated to quantify light quality in the understorey (0–50 cm height). We also identified relationships between light quality and native and non‐native seedling presence, diversity and abundance. Together, these data can help to determine the restoration potential of HLWF. Linear mixed‐effect modelling showed that native‐dominated forests had significantly greater R:FR than P. cattleyanum‐dominated forests, demonstrating a transformation in the light environment with increased invasion. Heterogeneity in R:FR varied more across sites than among forest types. In both native‐dominated and partially invaded forests, there were more native seedlings in the low‐quality R:FR (0.0–0.40) category and fewer in the medium‐ (0.41–0.70), and high‐quality (≥0.71) light categories than would be expected by chance, and there were no native seedlings in the P. cattleyanum‐dominated forests. Native‐dominated forests had greater species richness and abundance of native seedlings than the partially invaded forests, likely due to propagule availability. However, the spatial clustering of seedlings, the mismatch of native seedlings in light environments less suitable, and a considerable proportion of open high‐quality microsites, highlights that conditions are not optimal for native species in HLWF in the long term. Synthesis and applications. The native‐dominated and partially invaded forests still hold conservation value, despite variation among sites. Seedling additions could be targeted to different R:FR environments and at different spatial scales, but the lack of a strong relationship between R:FR and seedling number suggests that other factors besides light quality should be considered in seedling enrichment or other management activities.

Impact of land use on shallow groundwater quality for domestic use in Mathira East Sub-County in Kenya

Shallow groundwater sources of boreholes and springs form major types of water resources used in rural areas of Kenya. Information on their status is inadequate, thus hindering their sustainable management. This study investigated the relationship between land-use types, groundwater sources and water quality. Thirty-six randomly selected groundwater sources were sampled in Mathira East Sub-County from four stratified land-use types of forest, tea, coffee, and urban, with 18 samples collected for either shallow boreholes or springs. The Principal Component Analyses (PCA) grouped groundwater resources into three groups according to groundwater sources and land-use types. Spearman rank correlation, one-way ANOVA and unpaired t-test found that land use types significantly influenced shallow groundwater quality along an increasing gradient of landscape disturbances from the less disturbed forest, then tea, coffee and lastly to the severely disturbed, the urban area. The most affected water parameters were turbidity, conductivity, NO3–N, phosphates and faecal coliforms and their variation was attributed to land-use changes, especially agricultural intensification and urbanisation. The significant variations in other water quality parameters (total hardness, total alkalinity, dissolved oxygen, pH, manganese and fluoride) were attributed to water–rock interactions, climatic factors and land use changes. Calculated Water Quality Index (WQI) with faecal coliforms parameter from groundwater sources were found unsuitable for domestic use, while the ones derived without faecal coliforms parameter were found safe for human use. Overall, shallow groundwater sources were contaminated and unsafe for human use. This study recommends regular monitoring of key water parameters affected by land use changes to support the sustainable management of shallow groundwater resources in Mathira East Sub-County and the larger region of South Sahara Africa.

Climate change ecological vulnerability and hotspot analysis of himalayan forests in North-Eastern region, India

The Himalayan forests are vulnerable to climate change leading to disturb the current flow of critical ecosystem services to the dependent population. Present study attempts to evaluate the current vulnerability status of major forest types in Nagaland, India due to climate change along with identifying the hot spots for mitigating the vulnerability of the forests. Vulnerability of mixed moist deciduous, pine, wet hill and wet temperate forests were evaluated using the IPCC framework. Local Moran's I analysis, hot spot analysis and a histogram analysis of the vulnerability were made in QGIS. Field data such as Shannon-Wiener Index and Importance Value Index along with secondary data such as edaphic factors, vegetation factors and climatic variables were used for vulnerability analysis. Analysis results that mixed moist deciduous forests had the highest area in under high-high clusters, hot spots and was highly vulnerable. The result suggests that very dense or moderately dense forest cover were less vulnerable than low density forests in the region. The study provides baseline information along with identification of vulnerable hot spot forests for future climate change policy and management of resources at the division level. The study suggests strengthening the less dense forests along with increasing the biodiversity through suitable strategy for mitigating the vulnerability.