Vegetation Characteristics Research Articles

Identification and Mapping of Eucalyptus Plantations in Remote Sensing Data Using CCDC Algorithm and Random Forest

Eucalyptus plantations are one of the primary artificial forests in southern China, experiencing rapid expansion in recent years due to their significant socio-economic benefits. This expansion has raised concerns about the ecological environment, necessitating accurate mapping of eucalyptus plantations. In this study, the phenological characteristics of eucalyptus plantations were utilized as the primary classification basis. Long-term time series Landsat and Sentinel-2 data from 2000 to 2022 were rigorously preprocessed pixel by pixel using the Google Earth Engine (GEE) platform to obtain high-quality observation data. The Continuous Change Detection and Classification (CCDC) algorithm was employed to fit the multi-year observation data with harmonic curves, utilizing parameters such as normalized intercept, slope, phase, and amplitude of the fitted curves to characterize the phenological features of vegetation. A total of 127 phenological indices were generated using the Normalized Burn Ratio (NBR), Normalized Difference Fractional Index (NDFI), and six spectral bands, with the top 20 contributing indices selected as input variables for the random forest algorithm to obtain preliminary classification results. Subsequently, eucalyptus plantation rotation features and the Simple Non-Iterative Clustering (SNIC) superpixel segmentation algorithm were employed to filter the results, enhancing the accuracy of the identification results. The producer’s accuracy, user’s accuracy, and overall accuracy of the eucalyptus plantation map for the year 2020 were found to be 96.67%, 89.23%, and 95.83%, respectively, with a total area accuracy of 94.39%. Accurate mapping of eucalyptus plantations provides essential information and evidence for ecological environment protection and the formulation of carbon-neutral strategies.

On the issue of forecasting crop yields for the purposes of adaptive landscape agriculture

Long-term monitoring (1998–2023) of the yield of clover-timothy grass stands of the first year of use was carried out in order to find patterns of influence of landscape environmental conditions on it in various agroclimatic conditions. The research was conducted within the moraine hill located at the Gubino VNIIMZ agro-testing site in the Tver region. Soil-forming rocks are two-membered deposits consisting of an upper layer composed of relatively light rocks, underlain by moraine bouldery loam. The grass stands were exploited without fertilizers in a single-cut mode on a field divided into 120 plots. Using regression analysis, the influence of landscape and soil environment factors was determined: relief, physical and agrochemical properties of soils on grass yield, as well as the dependence of the degree of this impact on climatic conditions. It was found that the yield of perennial grasses is most strongly influenced by various fractions of the granulometric composition of soils – from stones to dust (up to 16 % of its variability) and the altitude of the location (up to 38 %), since the thermal and water-air characteristics of soils and vegetation largely depend on them. Terrain characteristics such as steepness and curvature of the surface have a minor impact on grass yield (up to 12 %). The degree of influence of agro-landscape environmental factors on the growth of grasses is largely regulated by fluctuations in weather conditions. “Climate scenarios” of a specific factor – sets of weather parameters under which its effect on the production process of a crop is manifested – in the years of sowing and mowing, as a rule, do not differ fundamentally. Knowing the nature of the influence of climatic factors allows us to more accurately predict crop yields within an agricultural landscape and, thus, optimize the location of crops on the territory of a particular farm.

Comparative study of five scab resistant apple cultivars

Vegetative and reproductive characteristics of five resistant apple cultivars budded on ‘М9-Т337’ rootstock were compared in the intensive orchard, planted at the density of 2380 trees per hectare (3.5 × 1.2 m) in the period 2017-2023. Trees were formed as tall spindle, under an insecticidal net against hail. Trees were grown under drip irrigation and sod-mulch system was applied. The cultivars FUJIONpbr and ENTERPRISE demonstrate greater trunk-cross section area, higher trees and greater crown volume to the tested cultivars. The smallest trees were noted in Cultivar GEMINI*. The lowest yield per unit area was obtained on cultivar FUJIONpbr. There was no significant difference among other cultivars. Despite of generally good characteristics the cultivar GEMINI* has relatively small fruits. Keywords: apple, vigor, productivity, fruit weight, yield

Oral history methods can reveal drivers of landscape transformation: Understanding land‐use legacies with local and traditional knowledge in Central Europe

Abstract Ecosystems and landscapes shaped by the intricate relationship between people and their natural environment embody the impact of many different past land‐use practices and historical events. However, in some regions, classical historical records of landscape change do not exist or are insufficiently detailed. Local communities' ecological memory can play an important role in filling this gap by reconstructing the socio‐ecologically relevant indirect drivers and their interactions, as well as identifying vegetation characteristics that are legacies of previous land‐use practices. We studied a rapidly transforming cultural landscape in Transylvania (Romania) by conducting 144 oral history interviews covering the last 70 years (before, during and after collective farming). The interviews revealed complex interactions of indirect drivers. Country‐scale political and economic changes affected the landscape with crop outflow during the collective system (1962–1989), resulting in labour outflow to cities from the 1960s. The latter reduced the time and attention devoted to haymaking and affected population ageing. Together with other drivers, this demographic change led to a major transformation of the traditional landscape by the 2010s. We identified 47 vegetation characteristics as land‐use legacies related to grasslands and classified them into general legacy types. Our results support that there was an opportunity to innovatively revive the traditional cultural landscape after the fall of communism, when local knowledge, and willingness to manage the landscape were still present, but financial assets and government support were lacking. The indirect driver interactions led to the abandonment of traditional hay meadow management, resulting in a homogenising landscape with simplified land use dominated by sheep grazing and increasingly dependent on agricultural subsidies. We found that many vegetation characteristics of the studied species‐rich grasslands are only legacies of former land‐use activities, still known by locals but no longer applied. By creating knowledge partnerships, we can still learn about the past management and the functioning of such biodiversity‐rich cultural landscapes from the people who actively maintained them. We argue that this type of knowledge is essential to revive and adapt practices for protecting and managing species‐rich habitats across European cultural landscapes and for supporting the planning of appropriate conservation management and subsidy schemes. Read the free Plain Language Summary for this article on the Journal blog.

Hengniu: Fast Bearing and High Yielding Coconut Varieties

Benefits of coconut varieties that stakeholders want are early bearing, high yielding, short stems, and slow growth for height. Most local tall coconut palms in Indonesia have stem height above 20 m, making it increasingly difficult to climb to harvest fruit or tapping sap thereby making the harvesting cost high. To breed varieties of desired characters, an evaluation trial was initiated in 2014 with BYD x MTT-S4, RAD x MTT-S4, and KHINA-1 as a control. The crossing was done in 2012 and seedlings planted in January 2014 at Mapanget Experimental Garden, Indonesian Palma Crops Research Institute, North Sulawesi. The study used a Randomized Block Design (RBD) of three types of coconut hybrids, four replications with a plot size of 16 trees. Morphological observations were carried out on stem, crown and leaf characters, inflorescences and flowers, nut production, fruit components, copra, oil content, and fatty acid composition. The results of ANOVA analysis and statistical tests obtained those vegetative characters, such as stem circumference and number of leaf, generative characters namely the number of bunches, first flowering, and fruit production of these three crosses at the age of 4 years after planting, did not show a significant difference. The first initial flowering was in the coconut hybrid of RBD x MTT-S4, which is 26 months, followed by BYD x MTT-S4 in 32 months and KHINA-1 in 36 months after planting. The results of the analysis of fruit and copra production at the age of 5 years showed a significant increase between hybrid coconuts. The highest to lowest fruit production was obtained in BYD x MTT-S4 hybrid coconut, RBD x MTT-S4, KHINA-1, which were 64 nuts, 44 nuts and 26 nuts /palm respectively, or estimated copra production was 2.26 tons, 1.45 tons and 0.88 tons copra/ha. At 6 years old the harvest of fruits from the three hybrid coconuts is obtained sequentially 118 nuts, 99 nuts and 94 nuts/palm. While estimation of copra yield per hectare is found the highest in BYD x MTT-S4 hybrid coconut is 3.86 ton/ha/year and this yield differently significant compare with RBD x MTT-S4 is found 3.04 ton/ha/year, and control hybrid of KHINA-1, which is about 2.74 ton/ha/year. Based on the production potential, hence the estimated optimum production when aged over 10 years can reach more than 5 tons/ha/year. The hybrid coconut variety BYD x MTT-S4 is released in October 2019 under the name HENGNIU.

Habitat quality in farmland influences the activity patterns of giant Galapagos tortoises

AbstractMany Galapagos giant tortoises make seasonal migrations from arid lowlands in the wet season, to humid highlands in the dry season. However, for critically endangered Western Santa Cruz giant tortoises (Chelonoidis porteri), at least 88% of the habitat in the highlands is now used for agriculture. To understand the impact of agricultural land use on tortoise behavior, we conducted 242 30-minute observations of tortoises on farms. We (1) recorded the time tortoises spent eating, walking, and resting in three different land-use types, (2) measured their temperature, and (3) quantified their selection of fine-scale vegetation characteristics. We found that tortoises rest for significantly longer periods when they are in abandoned land, compared to livestock, grazing, and touristic land. Generally, tortoises rested for longer when they were cooler. Time spent eating was increased by the density and proportion of ground vegetation, while time spent walking was reduced by tall vegetation. These findings suggest that the distribution of land-use types and the fine-scale composition of thermoregulatory and grazing resources within farmland have important implications for the behavior of tortoises while in human-modified land. Wildlife managers and landowners wishing to support tortoises on farms should focus on rehabilitating abandoned land and encouraging a heterogenous mix of sun and shade, and short ground vegetation across land-use types.

Evaluation of variability of morphometric traits of plants and age spectrum of cenopopulations of Matthiola daghestanica (Brassicaceae) of the Piedmont and Mid‐mountain Dagestan, Russia

Aim: Study of intra‐ and interpopulation variability of quantitative traits of Matthiola daghestanica (Conti) N. Busch and assessment of the age spectrum of natural cenopopulations of Piedmont and Mid‐mountain Dagestan. The material consisted of 90 plants (shoots with inflorescences) taken from coenopopulations of various locations of the studied species (450, 610 and 960 m above sea level). An analysis of the variability of 12 morphological traits of M. daghestanica was carried out. To assess the age spectrum, 5x5 m test plots were laid out at three points (75 m²), where the age (ontogenetic) states of M. daghestanica guided by methods from the works of T.A. Rabotnov (1950) and A.A. Uranov (1957).The variability of the morphological traits of the Dagestan endemic M. daghestanica has been studied and its age spectrum in the natural cenopopulations of Piedmont and Mid‐mountain Dagestan has been assessed. The most variable were the weight traits. Analysis of the significance of the differences between the selected groups using the t‐test confirmed that “Chakh‐Chakh” is highly isolated from other coenopopulations, and to the greatest extent from “Chirkata”. The linear trait “length vegetative features” introduces the greatest significant differences between all coenopopulations. The percentage of age states from the total number of individuals varies among populations. The age spectrum of M. daghestanica in the “Chirkata” cenopopulation is represented by a predominance of the juvenile (25 %) and virginal (25 %) groups and in the “Ashilta” cenopopulation by the adult group (23.9 %). Among the age states of the generative period in all cenopopulations, young generative individuals prevail (16.7–19.4 %). The largest number of middle‐aged generative individuals is in the “Chakh‐Chakh” cenopopulation (16.3 %).Analysis of the variability of morphological characteristics of M. daghestanica plants showed that linear and numerical traits for the three cenopopulations are less variable. Significant variability was revealed in weight characteristics: “mass caulis and leaves” (518.3–818.7 mg); “total mass shoot” (990.7–1342.8 mg). The squared Mahalanobis distances of the characters studied revealed the isolation of the “Chakh‐Chakh” cenopopulation from the other two (“Achilta”, “Chirkata”). The age spectrum of M. daghestanica coenopopulations is similar in the Piedmont and Mid‐mountain Dagestan, despite the different number of age states. Cenopopulations of M. daghestanica are normal, capable of self‐renewal, characterized by recovery indices of 1.2–2.8 %.

The effect of foliar spraying of some micronutrients and lanthanum on the morphological and physiological characteristics of summer savory (Satureja hortensis L.) under hydroponic and soil conditions

BackgroundThe use of lanthanum (La) as a rare element has increased in agriculture. Summer savory (Satureja hortensis L.) is an herbaceous and medicinal plant that has received attention recently. The present study aimed to investigate the effects of foliar application of zinc (Zn), copper (Cu), manganese (Mn), and La at different growth stages, including vegetative, reproductive, and vegetative to harvest on morphological and physiological traits of S. hortensis under hydroponic and soil conditions in the greenhouse. The study was arranged in a factorial experiment based on a completely randomized design (CRD) with three replications.ResultsResults of hydroponic condition showed that foliar application of Cu, Zn, and Mn were the most effective treatments to improve the measured morphological and physiological traits. Moreover, La was not more appropriate in increasing the quantitative and qualitative characteristics. Also, results showed that in soil cultivation, foliar application of micronutrient elements increased the ratio of leaf-to-stems, antioxidant compounds, and the percentage of essential oils, while the application of Mn, Cu, Zn, and La did not have positive effects on the increase in vegetative characteristics in all three stages of foliar application compared with the control treatment.ConclusionsCu, Zn, and Mn in appropriate concentrations can increase growth and physiological characteristics of summer savory in hydroponic systems.

From Outside to Inside: The Subtle Probing of Globular Fruits and Solanaceous Vegetables Using Machine Vision and Near-Infrared Methods

Machine vision and near-infrared light technology are widely used in fruits and vegetable grading, as an important means of agricultural non-destructive testing. The characteristics of fruits and vegetables can easily be automatically distinguished by these two technologies, such as appearance, shape, color and texture. Nondestructive testing is reasonably used for image processing and pattern recognition, and can meet the identification and grading of single features and fusion features in production. Through the summary and analysis of the fruits and vegetable grading technology in the past five years, the results show that the accuracy of machine vision for fruits and vegetable size grading is 70–99.8%, the accuracy of external defect grading is 88–95%, and the accuracy of NIR and hyperspectral internal detection grading is 80.56–100%. Comprehensive research on multi-feature fusion technology in the future can provide comprehensive guidance for the construction of automatic integrated grading of fruits and vegetables, which is the main research direction of fruits and vegetable grading in the future.

Detection of underground natural gas pipeline micro-leakage based on UAV hyperspectral remote sensing and GIS

ABSTRACT Detection of underground natural gas pipeline micro-leakage based on unmanned aerial vehicle (UAV) hyperspectral remote sensing and GIS. Hyperspectral images can indirectly detect underground natural gas pipeline micro-leakage through spectral and spatial variation characteristics of surface vegetation. However, most of existing studies were based on ground-mounted platforms, which could only perform small-range single-point detection and might occur misidentifications. UAV hyperspectral remote sensing can allow wide-range detection of surface vegetation. Moreover, underground pipeline distribution GIS data can provide prior knowledge about leakage points to exclude misidentifications. Therefore, a natural gas pipeline micro-leakage experiment was set up. UAV hyperspectral images of grasslands and pipeline distribution vector data were obtained, which led to a proposed new wide-range multi-points detection methodology of underground natural gas micro-leakage. Firstly, the vegetation identification index (WVI) R 470 + R 674 / R 555 + R 750 was designed based on WOA–VMD (whale optimization algorithm – variational modal decomposition) to segment and extract the vegetation stress zones. Then, UAV- and GIS-based natural gas micro-leakage vegetation stress identification model was constructed to obtain the leak points of natural gas micro-leakage. Finally, the recognition ability was evaluated by comparing with three stress vegetation identification indices proposed in previous studies. The result showed that there was no missing or false detection in identification results; the identification and positioning effect was better than other indices, which could meet the practical application requirements.

Characterizing Juvenile Common Snook and Tarpon Habitat to Guide Conservation and Restoration of Coastal Wetlands

To conserve or restore juvenile fish habitat, resource managers, restoration practitioners, and engineers need fine-scale information to understand what conditions they need to preserve or what specifications are needed to create new habitat. The objective of this study was to develop statistical models using a dataset of 18 coastal ponds in Southwest Florida, USA, to predict the abundance of juvenile common snook Centropomus undecimalis (hereafter snook) and presence of juvenile tarpon Megalops atlanticus, both of which are flagship species used for conservation and restoration of subtropical and tropical wetlands. Model predictors included water conditions and characteristics of vegetation, sediment, and geographic position. Modeling results indicated that juvenile snook used coastal ponds that were directly connected to tidal creeks. In contrast, juvenile tarpon were more likely to be present in coastal ponds that were separated from tidal creeks by dense mangrove forest (e.g., elevation > 0.48 m above Mean Low Water) characterized by highly organic sediment and low dissolved oxygen, to which tarpon are well adapted. Overlap between snook abundance and tarpon presence was greatest where connections between ponds and the nearest tidal creek were at a relatively low elevation (e.g., -0.12 m relative to Mean Low Water). Although these findings are most applicable to management and conservation of populations in areas along the Gulf coast of Florida (i.e., in areas of similar tidal range and coastal geomorphology), incorporating more detailed habitat surveys to better capture landscape context, geomorphology, and connectivity into fish sampling designs should be broadly applicable to estuarine fish ecology.

Characteristics of sublittoral vegetation at the northwestern coast of the Japan Sea based on the concept of adaptive zone

Characteristics of sublittoral vegetation at the northwestern coast of the Japan Sea based on the concept of adaptive zone

Occupancy dynamics of the mottled owl Strix virgata using object-based image analysis along an urbanized Neotropical gradient

Urbanization has profound effects on wildlife. Although some species benefit or even thrive in urban environments, most species respond differently to the varying degrees of disturbance that can be found across an urbanized landscape. Quantifying the effects of urbanization in wildlife distributions, however, is complicated: species vary in their patterns of presence/absence, abundance, and detectability across spatial and temporal scales, e.g., daily, seasonal, or throughout the annual cycle. Here, we use occupancy models to offer a realistic approach to the study of populations of urban owls. Most studies on owl population dynamics have not considered temporal variation in occupancy between seasons or assess the uneven effects of urbanization along a habitat gradient. We investigated the seasonal habitat associations of mottled owls along an urban gradient in the Neotropical city of Xalapa, Veracruz, Mexico. Using high-resolution satellite images and object-based image classification techniques, were analyzed the relationship between different vegetation and environmental characteristics with the occupancy of mottled owls. We employed different sampling techniques, including playback surveys and silent listening periods, to detect the presence or absence of owls along a gradient from highest to lowest urbanization. Environmental data and different vegetation types were used to analyze the habitat associations of mottled owls during January (late non-breeding season) and May (late breeding season) of 2023. In total, we detected 68 mottled owls during the non-breeding season and 102 during the breeding season, with higher detection rates in areas with >28 % forest surface. Our results revealed that the best occupancy model included forest and forest division (occupancy), ambient noise and moonlight (detection) for the non-breeding season, as well as urban, forest, grass, and forest division (occupancy), and noise (detection) for the breeding season. The percentage of forested and grass areas positively influenced mottled owl occupancy while the percentage of urbanization and forest division influenced it negatively. Moonlight was positively related to mottled owl detection, while ambient noise had a negative effect on detection probabilities of mottled owls during both seasons. Forested areas emerged as pivotal for owl occupancy, indicating their sensitivity to forest changes along the urban gradient. With urban areas increasing, the interplay between forest division, ambient noise, and moonlight unveils critical insights into mottled owl behavior and habitat dynamics, underscoring the necessity for informed conservation strategies amidst urban expansion. Future research should survey different years to provide a more robust assessment of the dynamic occupancy of mottled owls in Neotropical urban gradients.

Assessment of the Spatiotemporal Dynamics of Suitable Habitats for Typical Halophytic Vegetation in China Based on Maxent Model and Landscape Ecology Theory

The widespread and complex formation of saline soils in China significantly affects the sustainable development of regional ecosystems. Intense climate changes and regional land use further exacerbate the uncertainties faced by ecosystems in saline areas. Therefore, studying the distribution characteristics of typical halophytic vegetation under the influence of climate change and human activities, and exploring their potential distribution areas, is crucial for maintaining ecological security in saline regions. This study focuses on Tamarix chinensis, Tamarix austromongolica, and Tamarix leptostachya, integrating geographic information systems, remote sensing, species distribution models, and landscape ecological risk (LER) theories and technologies. An optimized MaxEnt model was established using the ENMeval package, incorporating 143, 173, and 213 distribution records and 13 selected environmental variables to simulate the potential suitable habitats of these three Tamarix species. A quantitative assessment of the spatial characteristics and the area of their potential geographical distribution was conducted. Additionally, a landscape ecological risk assessment (LERA) of the highly suitable habitats of these three Tamarix species was performed using land use data from 1980 to 2020, and the results of the LERA were quantified using the Landscape Risk Index (LERI). The results showed that the suitable areas of Tamarix chinensis, Tamarix austromongolica, and Tamarix leptostachya were 9.09 × 105 km2, 6.03 × 105 km2, and 5.20 × 105 km2, respectively, and that the highly suitable habitats for the three species were concentrated in flat areas such as plains and basins. Tamarix austromongolica faced increasing ecological risk in 27.22% of its highly suitable habitat, concentrated in the northern region, followed by Tamarix chinensis in 16.70% of its area with increasing ecological risk, concentrated in the western and northern highly suitable habitats; Tamarix chinensis was the least affected, with an increase in ecological risk in only 1.38% of its area. This study provides valuable insights for the protection of halophytic vegetation, represented by Tamarix, in the context of China’s national land development.

Habitat requirements of Luronium natans (L.) Raf. in northern Belgium

We investigated the environmental range of Luronium natans populations in lower Belgium (Flanders) with particular focus on key factors influencing its population size and the interplay of nutrient availability and physical disturbances in determining its abundance. Soil calcium content and total phosphorus in the water layer were the only physical-chemical variables related to L. natans abundance. Physical water body and vegetation characteristics influenced population dynamics and incidence of reproductive strategies. The species has a ruderal character, and occurs early in vegetation succession or depends on regular physical disturbance events for prolonged presence. Presenting limited competitive abilities, especially in terms of light availability, the species is hindered by taller-growing vegetation. Large populations are typically associated with well-lit conditions. Its flexibility to switch between vegetative and generative reproduction strategies may be associated with nutrient and light conditions. The need for long-term monitoring to consider population dynamics and evaluate the effectiveness of conservation efforts is emphasized. Overall, our study provides further insight into the relation between abiotic conditions, population dynamics and conservation management and extends the basis for sustainable management of the remaining L. natans populations in Flanders and similar regions of Atlantic Europe.

Geomorphic characteristics influencing post-fire river response in mountain streams

As wildfires increase in frequency and severity, there is a growing interest in understanding river response to the wildfire disturbance cascade. Numerous headwater mountain catchments within the Cache la Poudre (Poudre) River basin in the Colorado Front Range, USA burned severely and extensively during the 2020 Cameron Peak fire. Debris flows and flash floods occurred in many of these catchments triggered by convective storms after the fire. The downstream effects of the floods and sediment varied along a continuum from attenuated and largely contained within the catchment, to releasing substantial volumes of water and sediment to the Poudre River. We conceptualize these catchments as exhibiting decreasing absorbance of post-fire disturbance along the continuum described above based on the geomorphic evidence of relative sediment export. We conceptualize characteristics on different spatial scales as driving or resisting response to disturbance and therefore impacting the absorbing capacity (ability to attenuate post-fire fluxes) of the catchment. As the magnitude of resisting characteristics increases at the catchment, inter- and intra- reach scales, we hypothesize that a catchment will increasingly absorb the impacts of the wildfire disturbance cascade. We conducted longitudinally continuous surveys to measure reach-scale characteristics within each study catchment. We focus on the catchment- and reach-scale geomorphic, vegetation, and burn characteristics. The floods observed at the study catchments illustrate fire influencing the elevation above which rainfall-induced flooding occurs due to the efficient conveyance of water from hillslopes to channels after wildfire. Results suggest that inter- and intra-reach spatial heterogeneity are better aligned with absorbance capacity than catchment-scale characteristics: greater absorbing capacity is associated with greater longitudinal variations in floodplain/channel width and more reaches with wide floodplains, low channel gradients, beaver-modified topography, and multi-stem deciduous vegetation. We connect the capacity to absorb the impacts of disturbance as informing the catchment response to wildfire disturbance.

The internal decay of wood is driven by the interplay between foraging Magellanic woodpeckers and environmental conditions

Although woodpeckers are known to forage in decaying trees, their contribution to internal wood decay is not well known. In this sense, non-destructive techniques for structural wood degradation provide an opportunity to quantitatively assess the role of woodpeckers in tree decay. We used sonic tomography to test that the trunks of living trees pecked by Magellanic woodpeckers show pronounced decay, which accelerates under environmental conditions favorable to wood-decaying fungi. The internal decomposition of wood and its decay rate were measured over four years on 156 living southern beech (Nothofagus) trees belonging to four dominant species of southern temperate forests in northern Patagonia. Half of these live trees had woodpecker feeding holes, while the rest served as controls. The percentage of decayed wood, although not severely decayed, increased in sections with the presence of woodpecker holes, but was also influenced by temperatures and biophysical variables such as elevation and topography. The trunk sections with woodpecker holes and exposed to intensive foraging showed accelerated inter-annual decay. Woodpecker foraging activity interacted with vegetation characteristics, resulting in accelerated wood decay in forest sites with an open canopy and exposed to water stress. Thus, sonic tomography provided evidence of a close relationship between woodpeckers and internal wood decomposition, suggesting a positive feedback mechanism regulated by forest disturbance. The approach used here can be extended to gain insight into the influence of woodpeckers on tree decay and mortality in regions experiencing severe drought and forest degradation, such as northern Patagonia.

Changes in the Spatial Patterns of Near‐Surface Soil Moisture and Environmental Controlling Factors Before and After a Landslide

ABSTRACTRain‐induced landslides are common natural disturbances in forested headwaters that can strongly alter the spatial distributions of hydrological and environmental features. Although many studies have reported the impacts of landslides on the spatial patterns of soil moisture or their environmental controls, studies that have used detailed in situ data sets collected at the same location before and after a landslide are lacking. This study investigated the spatial distribution pattern of the near‐surface soil moisture and environmental controls, including topographic, soil and vegetation features, in a headwater catchment using ground‐based measurements with high spatial resolution after a landslide in 2016. The data set was compared to measurements taken at the same location before the landslide to explore whether the landslide altered the amount, spatial distribution, or potential controlling factors of near‐surface soil moisture. The mean soil moisture decreased across the site after the landslide, even under conditions of greater rainfall input than before the landslide. Spatial variation in soil moisture decreased in the high‐disturbance area but increased in the low‐disturbance area, although autocorrelation distances of soil moisture changed little. The relationships between the spatial mean and standard deviation of soil moisture markedly changed from a convex‐upward shape to a convex‐downward shape in the highly disturbed area. This indicates that the spatial mean of soil moisture exhibited its greatest spatial variation under moderate conditions before the landslide, with the lowest spatial variation occurring after the landslide. Most of the same controlling factors (i.e., slope gradient, topographic wetness index, vegetation density, soil porosity and saturated hydraulic conductivity) were explored after the landslide, but their influence levels greatly decreased or even disappeared. Thus, the landslide weakened the spatial connectedness between soil moisture and environmental features, which has not yet been restored 6 years after the landslide. We suggest that the connectedness between hydrological responses and environmental features is crucial for restoration. Their connectedness can serve as an indicator to identify the stage of ecological succession from the disturbances of a landslide.

Characteristics of forest understory herbaceous vegetation and its influencing factors in biodiversity hotspots in China

Forest ecosystems, especially within biodiversity hotspots, heavily rely on the often-overlooked understory herbaceous communities (USHC) for their structural integrity and ecological functions. Because of their modest stature, these communities have garnered insufficient attention from researchers. Therefore, in this study attention is focused on USHC, which attempts to fill this research gap. To achieve this, we established 105 sample plots in 2022 within forest ecosystems situated in the biodiversity hotspot of southwest China. Our investigation unveiled a rich biodiversity tapestry, identifying 424 plant species from 108 families and 284 genera. Notable were the 217 herbaceous species identified in the understory layer, representing 67 families and 163 genera. These understory herbaceous species accounted for 51.2 % of the overall species count. Through a detailed analysis, the sample plots were categorized into eight distinct communities using a two-way indicator species analysis. These communities exhibited diverse variations in species composition, diversity, biomass, and nutrient characteristics. Notably, community I (Eucalyptus robusta Smith + Rubus corchorifolius L. f. + Alternanthera philoxeroides (Mart.) Griseb.), V (Camptotheca acuminata Decne + Rubus parkeri Hance + Iris tectorum Maxim), VIII (Platycladus orientalis (L.) Franco + Viburnum dilatatum Thunb. + Cyclosorus interruptus (Willd.) H. Ito) stood out for their exceptional species diversity and productivity. Moreover, correlation analyses highlighted the substantial impact of topographic and soil factors on USHC. Altitude, soil water content, and total carbon content emerged as the primary determinants of species diversity. Biomass demonstrated close associations with total soil carbon and nitrogen. Furthermore, the nutrient characteristics displayed significant correlations with soil nutrient contents. These findings underscore the critical importance of prioritizing USHC attention in forest conservation and management strategies within biodiversity hotspots. The implications strongly advocate for the inclusion of these communities in planning and decision-making processes, emphasizing their pivotal role in maintaining structural and functional diversity in ecosystems.

A Strategic Framework for Establishing Additional In Situ Data Acquisition Sites for Satellite Data Calibration and Validation: A Case Study in South Korean Forests

This study aims to evaluate the representativeness of Calibration/Validation (Cal/Val) sites for satellite data, develop a framework for establishing new Cal/Val sites, and propose a heterogeneity index to be applied within this framework, specifically focusing on South Korea. The proposed framework assesses the representativeness of existing Cal/Val sites, and, if found inadequate, provides a methodology for optimizing the location and number of additional Cal/Val sites, along with a prioritization strategy for their installation. Furthermore, the framework includes a methodology for evaluating the suitability of utilizing existing ground observation networks as additional Cal/Val sites and for prioritizing their use. The heterogeneity index is derived by synthesizing differences in geographic, climatic, vegetation, and spectral characteristics between the current Cal/Val sites and the broader regions. A higher heterogeneity index indicates significant divergence from existing Cal/Val sites across these factors, highlighting areas with a need for additional Cal/Val sites and a higher expected impact from their establishment. This index serves as a key tool within the framework to determine the optimal locations and number of new Cal/Val sites, as well as to evaluate the efficacy of utilizing existing ground observation networks. The framework was applied to South Korea, where the representativeness of the current eight Cal/Val sites was found to be insufficient. The optimal number of Cal/Val sites was determined to be 33, requiring the addition of 25 new sites in South Korea. The southeastern peninsula and surrounding islands were identified as priority regions for new installations. Additionally, the potential for utilizing the existing ground observation network was examined. Twenty-three Automatic Mountain Meteorology Observation System (AMOS) sites in South Korea were selected and compared with the optimized Cal/Val sites. The inclusion of these 23 AMOS sites was found to significantly improve representativeness, approaching the level of the optimized Cal/Val sites. This strategic deployment is expected to enhance the accuracy and reliability of remote sensing data, contributing to improved environmental monitoring and research in South Korea.