Forest Ecosystems Research Articles

Capturing drought stress signals: The potential of dendrometers for monitoring tree water status.

The severity of droughts is expected to increase with climate change, leading to more frequent tree mortality and a decline in forest ecosystem services. Consequently, there is an urgent need for monitoring networks to provide early warnings of drought impacts on forests. Dendrometers capturing stem diameter variations may offer a simple and relatively low-cost opportunity. However, the links between stem shrinkage, a direct expression of tree water deficit (TWD), and hydraulic stress are not well understood thus far. In this study, we exposed two widespread conifers Pinus sylvestris and Larix decidua to lethal dehydration by withholding water and closely monitored TWD, midday water potential ($\psi $), and midday stomatal conductance ($g_{s}$) under controlled greenhouse conditions. We found strong relationships between the three variables throughout the dehydration process, particularly suggesting the potential for continuous $\psi $ predictions and stomatal closure assessments. However, the relationships decoupled during recovery from severe drought. We also identified TWD thresholds that signal the onset of drought stress and tissue damage, providing insights into stress impacts and recovery potential. While these findings are promising, challenges remain in practically transferring them to field set-ups by suitable TWD normalization. Importantly, we observed that midday $g_{s}$ was drastically reduced when TWD persisted overnight, providing a directly applicable drought stress signal that does not require normalization. In conclusion, while challenges remain, our results highlight the potential of dendrometers for monitoring tree water dynamics. Implementing dendrometer networks could support the development of early-warning metrics for drought impacts, enabling large-scale monitoring in diverse settings, such as urban areas and forest ecosystems.

Carbon Sequestration and Stability and Soil Erosion in Forest Ecosystems

Carbon Sequestration and Stability and Soil Erosion in Forest Ecosystems

Litter and Root Removal Modulates Soil Organic Carbon and Labile Carbon Dynamics in Larch Plantation Ecosystems

Plant detritus plays a crucial role in regulating belowground biogeochemical processes in forest ecosystems, particularly influencing labile carbon (C) dynamics and overall soil C storage. However, the specific mechanisms by which litter and roots affect soil organic carbon (SOC) and its components in plantations remain insufficiently understood. To investigate this, we conducted a detritus input and removal treatment (DIRT) experiment in a Larix principis-rupprechtii Mayr plantation in the Taiyue Mountains, China, in July 2014. The experiment comprised three treatments: root and litter retention (CK), litter removal (LR), and root and litter removal (RLR). Soil samples were collected from depths of 0–10 cm and 10–20 cm during June, August, and October 2015 to evaluate changes in soil pH, water content (SW), SOC, dissolved organic carbon (DOC), readily oxidizable organic carbon (ROC), and microbial biomass carbon (MBC). The removal of litter and roots significantly increased soil pH (p < 0.05), with pH values being 8.84% and 8.55% higher in the LR and RLR treatments, respectively, compared to CK treatment. SOC levels were significantly reduced by 26.10% and 12.47% in the LR and RLR treatments, respectively (p < 0.05). Similarly, DOC and MBC concentrations decreased following litter and root removal, with DOC content in August being 2.5 times lower than in June. Across all treatments and sampling seasons, SOC content was consistently higher in the 0–10 cm depth, exhibiting increases of 35.15% to 39.44% compared to the 10–20 cm depth (p < 0.001). Significant negative correlations were observed between SOC and the ratios of ROC/SOC, pH, DOC/SOC, and MBC/SOC (R = −0.54 to −0.37; p < 0.05). Path analysis indicated that soil pH had a significant direct negative effect on SOC (p < 0.05), with a standardized path coefficient (β) of −0.36, while ROC had a significant direct positive effect on SOC (β = 0.66, p < 0.05). Additionally, pH indirectly affected SOC by significantly influencing ROC (β = −0.69), thereby impacting SOC indirectly. Random forest analysis also confirmed that the ROC/SOC ratio plays a critical role in SOC regulation. This study reveals the complex interactions between litter and root removal and soil C dynamics in larch plantations, identifying soil pH and ROC as crucial regulator of SOC content. However, the short-term duration and focus on shallow soil depths limit our understanding of long-term impacts and deeper soil C storage. Future research should explore these aspects and consider varying climate conditions to enhance the applicability of our findings. These insights provide a scientific foundation for developing effective forest management strategies and forecasting changes in soil C storage in the context of climate change.

Climate and Altitude Drive Spatial and Temporal Changes in Forests on the Eastern Tibetan Plateau—Evidence from the Shaluli Mountain

Forests are widely distributed in terrestrial ecosystems, covering about one-third of the global land area. They play a key role in sequestering carbon, releasing oxygen, mitigating climate change, and maintaining ecosystem balance. The ecology of the Tibetan Plateau is very fragile, but the impact of environmental change on regional forest ecosystems is not yet clear. Located in the Eastern Tibetan Plateau, the Shaluli Mountain has the richest biodiversity and the widest distribution of forests on the Tibetan Plateau. Assessing the dynamics of forest change is the basis for correctly formulating forest management measures, and is important for regional biodiversity conservation. However, traditional field surveys have the shortcomings of high cost, being time-consuming, and having poor regional coverage in forest dynamics monitoring. Remote sensing methods can make up for these shortcomings. Therefore, in this study, satellite remote sensing images were used to extract forest information from 2000 to 2020 in Shaluli Mountain, and the main drivers of forest change were analyzed with full consideration of the Spatially Stratified Heterogeneity (SSH) of environmental factors. The results found that the forest area increased from 23,144.20 km2 in 2000 to 28,429.53 km2 in 2020, and the average Percentage of Forest Cover (PFC) increased from 19.76% to 21.67%, with significant improvement in forest growth. The annual minimum temperature (TMN), altitude, annual maximum temperature (TMX), and annual precipitation (PRE) were the main driving factors of forest change, with an average driving power (q-value) of 0.4877, 0.2706, 0.2342, and 0.2244, and TMN was the primary limiting factor for forest growth. In addition, the driving power of all environmental factors on forest change increased from 2000 to 2020. The results of this study can provide a basis for the development of forest management strategies, and provide reference materials for regional biodiversity conservation.

The Hydration-Dependent Dynamics of Greenhouse Gas Fluxes of Epiphytic Lichens in the Permafrost-Affected Region

Recent studies actively debate oxic methane (CH4) production processes in water and terrestrial ecosystems. This previously unknown source of CH4 on a regional and global scale has the potential to alter our understanding of climate-driving processes in vulnerable ecosystems, particularly high-latitude ecosystems. Thus, the main objective of this study is to use the incubation approach to explore possible greenhouse gas (GHG) fluxes by the most widely distributed species of epiphytic lichens (ELs; Evernia mesomorpha Nyl. and Bryoria simplicior (Vain.) Brodo et D. Hawksw.) in the permafrost zone of Central Siberia. We observed CH4 production by hydrated (50%–400% of thallus water content) ELs during 2 h incubation under illumination. Moreover, in agreement with other studies, we found evidence that oxic CH4 production by Els is linked to the CO2 photoassimilation process, and the EL thallus water content regulates that relationship. Although the GHG fluxes presented here were obtained under a controlled environment and are probably not representative of actual emissions in the field, more research is needed to fully comprehend ELs’ function in the C cycle. This particular research provides a solid foundation for future studies into the role of ELs in the C cycle of permafrost forest ecosystems under ongoing climate change (as non-methanogenesis processes in oxic environments).

Large-Area UAS-Based Forest Health Monitoring Utilizing a Hydrogen-Powered Airship and Multispectral Imaging

Abstract. Climate change is threatening forest ecosystems worldwide by inducing various abiotic and biotic disturbances. In Europe, the European spruce bark beetle (Ips typographus L.) poses a significant threat, causing serious mortality in mature Norway spruce (Picea abies H. Karst.) stands. Rapidly evolving remote sensing technologies offer valuable tools for monitoring forest health, enabling timely management operations. This study presents a novel approach for large-area forest health monitoring using Uncrewed Aircraft Systems (UAS) and multispectral imaging. The research focuses on a hydrogen-powered Beyond Visual Line of Sight (BVLOS) airship for efficient monitoring of disturbances caused by I. typographus. A specific challenge is training machine learning models capable of covering wide areas. Our objective was to study the potential of deep learning models, including transfer learning and fine-tuning techniques, in developing the scalability and accuracy of UAS-based monitoring for detecting individual spruce trees and classifying their health. The approach was empirically evaluated in a study site in North Karelia, Finland. A multispectral image dataset was collected over a 1.3 km2 test area in May 2023 in a BVLOS setting operated from a command centre 75 km away. The results indicated that employing transfer learning significantly improved classification accuracy compared to training models from scratch, showing potential for implementing scalable machine learning methods for large-area UAS surveys. The best model yielded F1-scores of 0.936 for healthy, 0.955 for dead, and 0.817 for non-spruce classes. Furthermore, the results indicated that BVLOS airships offered high accuracy while reducing emissions and labour associated with UAS monitoring.

Disentangling the Complex Effects of Seasonal Drought, Floor Mass, and Roots on Soil Microbial Biomass in a Subtropical Moist Forest

Severe seasonal droughts driven by global climate change significantly alter the cycling of carbon and nutrients in forest ecosystems, while the investigation into the impacts of floor mass and plant roots on soil microbial biomass within the context of recurrent seasonal droughts is still rare. To investigate the environmental determinants governing soil microbial biomass with the escalating severity of seasonal droughts, we conducted a study in a montane subtropical moist evergreen broad-leaved forest in southwestern China from June 2019 to May 2023. The study results revealed that soil microbial biomass, as well as soil moisture, floor mass, and plant roots, showed an apparent single-hump modal within one year. In the comparative analysis of the soil microbial biomass fluctuation amplitudes across control and watered plots, a discernible disparity was observed, indicating significant differences in microbial biomass dynamics between the respective experimental conditions. The pooled data revealed a statistically significant influence of seasonal drought, floor mass, plant roots, and their reciprocal interactions on the soil microbial biomass, highlighting these factors as pivotal determinants of microbial community dynamics. This study elucidates the interactive regulatory mechanisms by which seasonal drought, floor mass, and plant roots collectively modulate soil microbial biomass within tropical and subtropical forests, offering insights into the complex ecological processes governing microbial community dynamics. This interactive regulation might influence the trajectory of plant species and soil microbial communities, facilitating their adaptive development and evolutionary responses.

Host trees partially explain the complex bacterial communities of two threatened saproxylic beetles.

Microorganisms are integral to ecosystem functioning and host adaptation, yet the understanding of microbiomes in diverse beetle taxa remains limited. We conducted a comprehensive study to investigate the microbial composition of two red flat bark beetle species, Cucujus haematodes and C. cinnaberinus, and assessed the influence of host taxonomic relatedness and host tree species on their microbiomes. We sampled 67 larvae of two Cucujus taxa taken from 11 host tree species. 16S rRNA V4 fragment sequencing revealed distinct microbial communities associated with each Cucujus species, with host tree species significantly influencing microbiome composition. Alpha and beta diversity metrics indicated significant differences between microbial communities in both beetle and host tree species. Principal component analysis indicated distinct clustering based on host tree species but not for beetle species. This overlap could be attributed to the similar ecology of both Cucujus species. The detection of various bacteria, among which some have already been reported in saproxylophagous beetles, suggests that the red flat bark beetles ingest the bacteria via foraging on other wood-dwelling invertebrates. Our findings show the complex interplay between host taxonomy, microhabitat and microbial composition in Cucujus, providing insights into their ecological roles and conservation implications. This research helps to fill the gap in understanding the microbial dynamics of saproxylic beetles, sheds light on factors shaping their microbiomes and highlights the importance of considering both host species and environmental conditions when studying insect-microbe interactions in forest ecosystems.

Reduced predation and energy flux in soil food webs by introduced tree species: Bottom‐up control of multitrophic biodiversity across size compartments

Abstract The introduction of non‐native tree species has become a global concern and may disrupt native communities and related ecosystem functions. Soil food webs regulate organic matter decomposition and nutrient cycling in forests with their feeding activities, but evaluating consequences of the introduction of tree species on soil invertebrates is challenging due to the complex trophic structure and wide range in body size of soil invertebrates. Here, we employed an energetic food web approach and estimated the energy flux in soil food webs using a four‐node model including soil meso‐ and macrofauna decomposers and predators. We examined pure and mixed stands of native European beech (Fagus sylvatica), introduced Douglas fir (Pseudotsuga menziesii) and native range‐expanding Norway spruce (Picea abies) across site conditions. Compared to native forests, introduced tree species reduced total fresh mass of macrofauna predators by 92% at sandy sites but not that of decomposers, suggesting trophic downgrading in soil food webs by Douglas fir. The energy flux in mixed forests was intermediate between respective monocultures, suggesting that tree mixtures mitigate potential negative impacts of introduced tree species on food web functioning. Across size classes, soil macrofauna responded more sensitively to changes in environmental conditions than soil mesofauna. Additionally, total energy flux positively correlated with species richness, pointing to the significance of soil biodiversity for trophic functionality. The energy flux through mesofauna outweighed that through macrofauna when considering energy loss to predators, highlighting the importance of mesofauna for decomposition processes in forest soil food webs. Overall, the study emphasizes the critical role of tree species composition, site conditions and soil biodiversity in driving energy flux through soil food webs and maintaining forest ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog.

Unveiling the Dynamics of Canopy Transpiration: A Novel Model Integrating Stomatal and Aerodynamic Resistance in Semi-Humid Forests

Canopy–atmospheric water vapor output resistance (gs) is a key parameter in researching forest canopy transpiration. It is important for quantifying the water vapor exchange in forest ecosystems. However, the method by which gs is determined has been controversial, and it cannot precisely represent water vapor exchange. This study aimed to develop a model to quantify the water vapor resistance between the canopy and the atmosphere in Platycladus orientalis (P. orientalis) forests using sap flow and meteorological factors monitoring data. The resistance model was constructed using the relationship between canopy stomatal resistance (gc) and aerodynamic resistance (ga) from the mechanism perspective, and sap flow data and measurements of meteorological variables were used to model the stomatal and aerodynamic resistance of the canopy. The results indicate that the canopy-atmospheric water vapor output resistance was closer to the measured values and showed a unimodal curve in the diurnal scale, and this change could provide more accurate measurements of tree transpiration. At the same time, the canopy-atmospheric water vapor output resistance was strongly influenced by wind speed and PAR when 0.2 m/s < u < 0.4 m/s (R2 = 0.871, p < 0.01). The stomatal and aerodynamic resistance were also both strongly influenced by wind speed, with the proposed model achieving a high degree of fit (R2 = 0.949, p < 0.01), providing a new tool for analyzing forest transpiration. This research provides a new perspective and technical reference for clarifying the mechanism of forest canopy water output.

Impacts of Participatory Forest Management on Land Use/Land Cover of Adaba-Dodola Forest in South Eastern Ethiopia and its Implication to REDD+ Implementation.

Despite various interventions to protect forests, many developing countries, including Ethiopia, continue to face substantial forest conservation challenges, particularly where local communities heavily rely on forests for their livelihoods. Recognizing the urgency of this issue, the government of Ethiopia introduced Participatory Forest Management (PFM) and devolved forest management responsibilities to enhance forest conservation. Therefore, this assessment examines the impacts of PFM on forest cover based on an analysis of the Land Use/Land Cover Change (LULCC) over the last 23 years in Adaba-Dodola, and its implications for REDD+ implementation. The study involved determining the LULCC of the Adaba-Dodola forest after the introduction of PFM from 2000 to 2023. Landsat images of 2000, 2012, and 2023 were analyzed to detect LULCC. The study result showed that the Adaba-Dodola forest cover increased by 1.83% since the PFM was introduced. The decreased agricultural land by 0.87% was the main factor attributed to the increase in shrub cover, while shrubland attributed to the rise in forest cover. Net areas of about 148 ha/year of shrublands were converted into forest land owing to significant forest regeneration, while shrublands had a net gain of 110.5 ha/year from agriculture and grasslands between 2000 and 2023. The increase in forest cover is attributed to the effectiveness of PFM in halting deforestation and promoting forest conservation. Thus, the PFM approach is a tool for preserving forest ecosystems and mitigating the adverse effects of deforestation and forest degradation, therefore would be used as an umbrella for implementing REDD+.

Linking symbioses with intrinsic chemical defences in conifers: Fungal‐mediated resistance against an invasive pathogen

Abstract Invasive pathogens threaten the sustainability of forest ecosystems globally. Trees possess intrinsic pathogen defence mechanisms, including major gene resistance (MGR) and quantitative disease resistance (QDR). Plant‐symbiotic fungi can enhance tree defences, generating far‐reaching ecosystem impacts. However, the specific contributions of various fungal guilds to this symbiont‐mediated resistance remain unclear. In this study, we inoculated six Pinus monticola seedling families exhibiting resistance (MGR or QDR) or high susceptibility to the introduced invasive pathogen Cronartium ribicola, the causative agent of white pine blister rust (WPBR), with endophytic and ectomycorrhizal fungi, either alone or in combination (symbiont treatments), in an open‐air greenhouse study. Over a period of 25 months, we monitored the growth, foliar terpene defences, and disease progression in trees before and after C. ribicola infection and in trees inoculated with the symbionts but never inoculated with C. ribicola. We observed enhanced inducible host defences and evidence of defensive priming in response to symbiont treatments. In WPBR‐free control treatments, differences in pine defences coincided with an increased seedling growth rate. For WPBR‐infected seedlings, symbiont treatments reduced disease symptoms in seedlings with QDR and to a lesser extent in susceptible families, but not in those with MGR. Furthermore, disease symptoms correlated with variations in terpene composition. Synthesis and applications: Interactions with fungal symbionts should be considered when breeding native trees for resistance against invasive pathogens. Our study underscores the capacity of endophytic and ectomycorrhizal fungi to enhance tree growth and defence while also reducing disease symptoms. We also show that fungi can induce long‐lasting changes in conifer foliar terpenes, suggesting potential applications in tree protection from invasive pathogens.

Fire-associated microbial shifts in soils of western conifer forests with Armillaria root disease.

With its influence on ecosystem processes and functions, the soil microbiome can interact with soilborne pathogens to facilitate or suppress plant disease development. These forest ecosystems are experiencing increased wildfire frequency and burn severity that could influence the fungal root pathogen, Armillaria solidipes, and interactions with the soil microbiome. We examined changes to the soil microbiome following three levels of burn severity, and examined how these changes correspond with A. solidipes, and a putatively beneficial species, A. altimontana. Following severe burn, there was a decreased relative abundance of ectomycorrhizal fungi associated A. altimontana. A. solidipes and associated microbial taxa dominated following high-severity burns, suggesting that severe fires provide suitable environmental conditions for these species. Our results suggest that shifts in the soil microbiome and an associated increase in the activity of A. solidipes following high-severity burns in conifer forests may result in priority areas for monitoring and proactive management of Armillaria root disease.

Population estimate and habitat association of Grant’s gazelle (Nanger granti Brooke, 1872) in the Ene Forest of Dale Sadi district, western Ethiopia

Grant’s gazelles (Nanger granti) are classified as of least concern by the IUCN, although their number is declining due to several factors. A few research studies have been conducted on Grant’s gazelle in Ethiopia. Thus, the present study was carried out to determine the population size and habitat association of Grant gazelle in the Ene Forest of western Ethiopia, comprising the dry and wet seasons. The study area was stratified into four habitats: woodland, mixed woodland, riverine forest, and grassland habitats. The data were collected using the direct observation technique. The data were analyzed using descriptive statistics and Pearson’s chi-square (χ2) test. The average estimated Grant gazelle population was 136 ± 23 individuals, with a density of 9/km2. The adult male-to-adult female sex ratio was 1:1.40 and 1:1.26 during the wet and dry seasons, respectively. The largest herd size (N = 6) was observed during the wet season, and the smallest (N = 4) was observed during the dry season. The highest numbers of Grant gazelles were observed in the grassland habitat during the wet season and in the woodland during the dry season. More Gazelles (N = 65) were observed in the woodland habitat compared to the other habitat types. The continued existence of the Grant’s gazelle population in the area and the suitability of the environment depend significantly on ongoing assessments of habitat change and management intervention.

Enhancing Forest Canopy Height Mapping in Kaziranga National Park, Assam, by Integrating LISS IV and SAR data with GEDI LiDAR data Using Machine Learning

Abstract. This study investigates the integration of spaceborne Global Ecosystem Dynamics Investigation (GEDI) LiDAR data with optical imagery from Linear Imaging Self Scanning Sensor (LISS IV), Sentinel-1 Synthetic Aperture Radar (SAR) and PALSAR data for continuous forest canopy height mapping in Kaziranga National Park (KNP), Assam for the years 2018 and 2022. Four machine learning models were trained and evaluated to assess the predictive ability of LISS IV data in conjunction with SAR variables. The mean canopy height was measured at approximately 8.58 m in 2018, which increased to about 9.07m in 2022. Results reveal Extreme Gradient Boosting (XGB) as the top-performing model, achieving an RMSE of 5.47m and an R2 of 0.55. In comparison, Random Forest (RF), Support Vector Machine (SVM), and k-Nearest Neighbors (kNN) achieved RMSE values of 5.49, 5.51, and 5.73, respectively. Analysis shows a prevalent occurrence of canopy heights below 5 meters in KNP (more than 35% of the area), while taller canopies beyond 20m can be found in less than 5% of the area. This finding underscores the importance of integrating satellite data and machine learning and highlights the novel application of LISS IV data in enhancing canopy height mapping. Furthermore, it represents the first comprehensive attempt to map canopy height in KNP, laying the groundwork for further research on biomass assessment and carbon sequestration in this vital biodiversity hotspot. Overall, the study highlights the potential of leveraging advanced remote sensing technologies and machine learning approaches for improved understanding and management of forest ecosystems.

Repeat airborne laser scanning to assess canopy height changes in tropical montane forests

Abstract. Tropical montane forests are vital ecosystems globally, preserving biodiversity, carbon stocks, and capturing moisture. We employed two airborne laser scanning (ALS) data sets to study changes in montane forest canopy heights in the Taita Hills, Kenya between 2014/2015 and 2022. We studied two forests, Ngangao (129 ha) and Yale (57 ha), which encompassed both indigenous montane forest and exotic plantations. First, forest types were mapped using field observations and aerial imagery, and then, canopy height changes were analysed using canopy height models at spatial resolution (i.e. the cell size) ranging from 1 m to 20 m. The results revealed overall increase in canopy height in the studied forests, with considerable spatial variation between the forest segments and main tree species. Planted exotic tree species, particularly eucalyptus but also pine and cypress, exhibited faster growth rates than native tree species. Point density differences between the ALS data sets can cause bias to estimation of canopy height changes. However, we observed that reducing the cell size of the canopy height models from 1 m to 10 m and 20 m, decreased the positive trend between point density difference and overestimation of canopy height change due to higher point density of more recent ALS data set. These findings contribute to our understanding on spatial complexity of montane forest ecosystems dynamics and help informing forest monitoring and development of management strategies for fragmented forests in montane regions.

Changes in Soil Physicochemical Properties and Fungal Communities Following a Forest Fire in the Pine Forest of Uljin, Republic of Korea

Soil samples from the rhizosphere of pine (Pinus densiflora) stands in the fire-disturbed Uljin forest were collected to analyze their physicochemical properties and fungal communities. In the burned area, soil pH decreased by 0.56, and organic matter content decreased by 0.32%p compared to the undisturbed area. Fungal community analysis revealed that all alpha diversity indices decreased in the burned area, but there were no differences according to fire severity. Soil pH, available phosphorus, and total nitrogen showed a positive correlation with the alpha diversity. Additionally, beta diversity analysis also indicated significant differences in the fungal communities between the burned area and the control sites (p value = 0.031). The changes in fungal communities were considered to be influenced by the decline in the order Atheliales, genus Russula, and genus Trechispora. A prediction analysis of the functional traits of fungi showed that the number of fungi involved in nutrient absorption and decomposition decreased in the burned area. It seems that the soil restoration of pine forests is progressing very slowly, as the soil fungi related to nutrient absorption by pine trees have not recovered even 18 months after the forest fire. Therefore, it is necessary to monitor continuous fungal communities in pine forest restoration after a forest fire to determine forest ecosystem restoration success and stabilization.

Early Sri Lankan coastal site tracks technological change and estuarine resource exploitation over the last ca. 25,000 years

The island of Sri Lanka was part of the South Asian mainland for the majority of the past 115,000 years, and connected most recently during the Last Glacial Maximum via the now submerged Palk Strait. The degree to which rising sea levels shaped past human adaptations from the Pleistocene and into the mid to late Holocene in Sri Lanka has remained unclear, in part because the earliest reliable records of human occupation come from the island’s interior, where cave sites have revealed occupation of tropical forest ecosystems extending back to 48 thousand years (ka). The island’s earliest known open-air sites are all much younger in date, with ages beginning at 15 ka and extending across the Holocene. Here we report the earliest well-dated open-air coastal site in Sri Lanka, Pathirajawela, which records human occupation back to ca. 25,000 years ago. We show that humans at Pathirajawela consistently adapted to changing ecosystems linked to sea level transgression and coastal evolution from the Last Glacial Maximum into the Holocene. The presence of anthropogenic shell midden deposits at the site from ca. 4.8 ka, focused almost exclusively on a single taxon, indicates intensification of estuarine resource exploitation, as humans responded to opportunities presented by the formation of new coastal ecosystems.

The Impact of Ecological Restoration on Soil Quality in Humid Region Forest Habitats: A Systematic Review

Ecological restoration is widely recognized as an essential technique for addressing soil degradation, biomass decline, and biodiversity loss. Improving and maintaining soil quality is critical to ensuring environmental sustainability and successful forest recovery. This systematic review aimed to assess the impact of ecological forest restoration efforts on soil quality in humid regions, as well as to compare the effectiveness of various ecological restoration strategies on soil quality indicators. Subsequently, a systematic search on various databases (e.g., Scopus and Google Scholar) yielded 696 records, of which 28 primary studies met the inclusion criteria. The results emphasized that chemical and physical soil properties are the key indicators for assessing ecosystem performance during forest restoration. The most commonly measured parameters were soil carbon, nitrogen, phosphorus, pH, bulk density, and soil porosity. It was shown that the restoration process required a longer duration to reach a comparable level of recovery as seen in mature forests, particularly in terms of fully restoring soil quality. Additionally, it has been noted that prior land use influences the length of time needed for soil quality recovery. In planted sites, soil quality may keep improving as the site ages, though it tends to stabilize after a certain period.

Analisa dan Pemetaan Kepadatan Hutan Mangrove di Wilayah Pesisir Pantai Gresik

The mangrove forest ecosystem in Ujung Pangkah sub-district plays a very important role in the lives of living creatures around it. The management and use of mangrove ecosystems by people in this sub-district tends to lead to the conversion of land into ponds, whether in the form of forest or emerging land. Cutting down trees in mangrove gforests is one of the causes of abrasion in several areas in Indonesia. Apart from abrasion, there is also accretion or addition of land around the Bengawan Solo estuary which provides access to the Pangkahwetan and Pangkahkulon coasts. The aim is to analyzezchanges in the area of mangrove vegetationgin Ujungpangkah. This research uses a remote sensing method known as the resolution concept, namely spatial resolution, temporal resolution, spectral resolution, radiometric resolution and layer resolution. Quantitative observations were made of changes in mangrove forest area using Landsat -8 imagery. The location of the Ujungpangkah ground is based on the conditions of the study location, in accordance with the results of initial image processing. Changes in the area of mangrove vegetation when viewed from remote sensing results in 2023 and 2024 experience visible differences, the distribution of mangroves will increase in 2024, namely there will be an increase in the area of vegetation. The distribution area of mangroves always changes every year. Either in the form of addition or reduction of area. Things that can affect the extent of mangrove distribution include 2 types of damage to the mangrove ecosystem in Ujung Pangkah District, namely abrasion and deforestation. The efforts made to overcome this problem include starting mangrove planting activities in the Banyuurip Mangrove Center (BMC) area. The results of data processing from the 2023 RBI map in Ujungpangkah District recorded a total area of ​​11904.93052 ha. The area is divided into several land uses, namely Mangrove covering an area of ​​1253.24609 ha and Non-Mangrove covering an area of ​​1525.32660 ha. Meanwhile, processing data from Lansat-8 in 2024 in Ujungpangkah District, the total area was recorded at 11904.93052 ha. Mangrove land use was recorded at 10651.68443 ha and non-mangrove land at 10379.60392 ha.