Multi-layer Vegetation Research Articles

Unraveling the characteristic spatial scale of habitat selection for forest grouse species in the boreal landscape

The characteristic spatial scale at which species respond strongest to forest structure is unclear and species-specific and depends on the degree of landscape heterogeneity. Research often analyzes a pre-defined spatial scale when constructing species distribution models relating forest variables with occupancy patterns. This is a limitation, as forest characteristics shape the species use of habitat at multiple spatial scales. To explore the drivers of this relationship, we conducted an in-depth investigation into how scaling forest variables at biologically relevant spatial scales affects occupancy of grouse species in boreal forest. We used 4,790 grouse observations (broods and adults) collected over 39,303 stands for 15 years of four forest grouse species (capercaillie, black grouse, hazel grouse, and willow grouse) obtained from comprehensive Finnish wildlife triangle census data and forest variables obtained from Airborne Laser Scanning and satellite data originally sampled at 16 m resolution. We fitted Generalized Additive Mixed Models linking grouse presence/absence in the Finnish boreal forest with forest stand structure and composition. We estimated the effects of predictor variables aggregated at three spatial scales reflecting the species use of the landscape: local level at stand scale, home range level at 1 km radius, and regional level at 5 km radius. Multi-grain models considering forest-species relationships at multiple scales were used to evaluate whether there is a specific scale at which forest characteristics best predict local grouse occupancy. We found that that the spatial scale affected the predictive capacity of the grouse occupancy models and the characteristic scale of habitat selection was the same (i.e., stand scale) among species. Different grouse species exhibited varying optimal spatial scales for occupancy prediction. Forest structure was more important than compositional diversity in predicting grouse occupancy irrespective of the scale. A limited number of forest predictors related to availability of multi-layered vegetation and of suitable thickets explained the occupancy patterns for all the grouse species at different scales. In conclusion, modeling grouse occupancy using forest predictors at different spatial scales can inform forest managers about the scale at which the species perceive the landscape. This evidence calls for an integrated multiscale approach to habitat modelling for forest species.

A Numerical Model of the Pollutant Transport in Rivers with Multi-Layer Rigid Vegetation

River water pollution is a key environmental issue to human society. How to effectively simulate the flow velocity and pollution transport in a vegetated river can provide a theoretical basis for solving such problems. Based on previous experimental data, this article uses the lattice Boltzmann method and random displacement method to simulate the velocity distribution and nutrient transport in multi-layer rigid vegetated rivers. The simulation results indicate that incorporating the drag force of the vegetation into the model according to different vegetation layers can effectively simulate the velocity in a multi-layer vegetated river. Incorporating the turbulent diffusion and mechanical diffusion effects of nutrients caused by vegetation into the model can effectively simulate the effects of multi-layer vegetation on nutrient transport. This model can provide effective predictions of the flow velocity and pollution transport in multi-layer vegetation.

Bird population and bird hunting in the rural ecosystem of Cijambu, Sumedang, West Java, Indonesia

Abstract. Suroso, Iskandar J, Withaningsih S, Nurjaman D, Iskandar BS. 2023. Bird population and bird hunting in the rural ecosystem of Cijambu, Sumedang, West Java, Indonesia. Biodiversitas 24: 4470-4484. Some rural West Java ecosystems have a high bird species diversity because they have forests, bamboo talun, mixed gardens, rice fields, and homegardens. Rapid population expansion, illicit bird shooting, forest degradation and conversion, and pesticide pollution have reduced rural bird species diversity. This study examined bird diversity in natural forests, coffee agroforestry, vegetable gardens, and bird hunting. Quantitative and qualitative research were used. The point count approach investigates bird species and populations, whereas detailed interviews with knowledgeable informants are used to study bird hunting. In natural forests, vegetable gardens, and coffee agroforestry, 67 species from 39 bird groups were found. The bird species diversity index in three habitats: vegetable garden (H'=2.59), coffee agroforestry (H'=2.97), and natural forest (H'=2.96). Based on the Sorensen Similarity Index, bird species in in vegetable garden and coffee agroforestry, vegetable garden and natural forest, and coffee agroforestry and natural forest had a similarity index of 31.03%, 22.22%, and 52.05%, respectively. These findings suggest that bird species may prefer coffee agroforestry over vegetable gardens. The coffee agroforestry system can generate complex vegetation canopy stratification with a multi-layered vegetation canopy, resembling natural forest stratification. Illegal hunting of bird species for trade is one of the causes of the decline in bird populations in rural ecosystems of West Java, including in Cijambu Village. The coffee agroforestry provides a habitat for rural birds.

Longitudinal velocity profile of flows in open channel with double-layered rigid vegetation

Aquatic vegetation of different heights is widely scattered in natural rivers and is conducive to their environmental function while affecting the flow hydrodynamic conditions. A semi-analytical velocity model is constructed and used to study the longitudinal velocity profile in open channel flow through double-layered rigid vegetation. The double-layered vegetation flow is separated into three zones according to the velocity profile: 1) nearly uniform distributed velocity zone 1A in the lower region of the short vegetation layer, 2) a mixing layer zone B, 3) uniform distributed velocity zone 2A in the upper region of the tall vegetation layer. Two force equilibrium equations about the gravity-driving and vegetation drag are solved to obtain the uniform velocity distribution equations in zone 1A and 2A. The velocity of zone 1A and B is further modeled as a linear superposition of two concepts: the uniform velocity distribution term of zone 1A and a hyperbolic tangent profile. Meanwhile, longitudinal velocity and the lateral vorticity profiles of open channel flow through double-layered rigid vegetation are studied by laboratory flume tests of different vegetation arrangements exposed to two water depths and three slopes. The experimental results show that the longitudinal velocity increases with the slope increase. The verification of the velocity model is based on the instantaneous velocity measured by Acoustic Doppler Velocimetry (ADV), which shows acceptable agreement, indicating that the model can give a reference to the longitudinal velocity of multi-layered vegetation flow in some cases. The effects of wake vortices and boundary friction on the model are further explored in the discussions. The results presented in this study could contribute to the management of aquatic vegetation configurations and the restoration of freshwater ecology.

Analysis of the Cooling and Humidification Effect of Multi-Layered Vegetation Communities in Urban Parks and Its Impact

As urbanization continues to accelerate, the urban heat island effects have become one of the most important issues affecting the urban environment and people’s living experience. Numerous studies have shown that urban parks and green spaces can effectively alleviate the problem of the urban heat island effect and provide cooling and humidifying effects. Vegetation communities are a fundamental part of urban parklands, and multi-layered vegetation communities are considered to have better cooling and humidifying effects. Previous studies have focused on comparative analyses between different cover types of vegetation communities but have not explored the differences in the cooling and humidifying effects of multi-layered vegetation communities of the same cover type. Therefore, the Olympic Forest Park in Beijing was selected as the subject of this study, and multi-layered vegetation-covered (tree-shrub-grass) with different degrees of densities and uncovered squares were selected for the control and comparison. The cooling and humidifying effects of multi-layered vegetation communities with different canopy densities at different times of the day through field measurements were studied, and the influencing factors for this were analyzed. The results show that the tree cover is the core factor affecting temperature; the degree of the canopy density of multi-layered vegetation communities is significantly and positively correlated with the intensity of cooling and humidification, and the cooling and humidifying effect of multi-layered vegetation communities increases as the degree of canopy density increases. The results of this study can provide some references for the planning and design of urban parks and green spaces.

ROADSIDE FOREST MODELING USING DASHCAM VIDEOS AND CONVOLUTIONAL NEURAL NETS

Abstract. Tree failure is a primary cause of storm-related power outages throughout the United States. Roadside vegetation management is therefore critical to electric utility companies to prevent power outages during extreme weather conditions. It is difficult to execute roadside vegetation management practices, at the landscape level, without proper monitoring of roadside forests’ physical structure and health condition. Remote sensing images and LiDAR are widely used to characterize the forest edge; however, the limitation on the temporal and spatial resolution for most of that dataset is a big challenge. Also, there is a need for a ground-level dataset that provides the vertical profile of the forest trees so that we can more accurately characterize the forest structure and health and recommend the optimal management strategies according to the local forest conditions. For the first time, we introduced Dashcam videos as an alternative to the existing aerial remote sensing data sources to characterize the roadside forest condition using the deep learning (DL) convolutional neural net (CNN) algorithms. In this study, we used dashcam videos taken during the leaf-on and leaf-off conditions and various weather conditions along the roadside. We trained a DLCNN model based on the U-Net and YOLO v5 architectures to classify the multilayer vegetation and detect utility poles and tree trunks alongside the road. Our experiment results suggest that a dashcam can be a viable alternative and complementary way to characterize the roadside vegetation and can be used in the management of roadside forests as a cost-effective data acquisition mechanism for utility companies.

Soundscapes of urban parks: An innovative approach for ecosystem monitoring and adaptive management

Urban foresters are addressing the challenge of urban biodiversity loss through management plans in the context of rapid urbanization. Protecting the integrity of the urban ecosystem requires long-term monitoring and planning for resilience as well as effective management. The soundscape assessment has attracted attention in this field, but applying the soundscape assessment in urban ecological monitoring requires a protocol that links soundscapes to the impact of resource management on biodiversity over time. The effective processing and visualization of large-scale data also remains an important challenge. The aim of this study was to better understand the relationship between soundscape and physical environment, and examine the feasibility of this innovative soundscape approach in highly urbanized areas. Soundscape recordings were collected for 20 urban parks twice on 4 consecutive days in Spring. A total of 691,200 min of sound material were automatically obtained. In order to track the spatio-temporal patterns of a soundscape and determine its potential suitability for ecosystem monitoring, our study characterized soundscape information by adopting 4 widely used acoustic indices: acoustic diversity index (ADI), bioacoustic index (BIO), normalized difference vegetation index (NDSI), and power spectral density (PSD). Daily patterns of PSD have provided a potential connection between soundscapes and bird songs, and 1–2 kHz presented a similar pattern that was linked to human activity. Through further modeling, we tested the relationship of soundscapes to physical environment characteristics. The results showed the importance of habitat vegetation structure for acoustic diversity. More vertical heterogeneity, with an uneven canopy height or multilayered vegetation, was associated with more acoustic diversity. This suggests that clearing ground cover may have a significant negative impact on wildlife. Our results suggest that soundscape approaches provide a way to quickly synthesize large-scale recording data into meaningful patterns that can track changes in bird songs and ecosystem conditions. The proposed approach would enable regular assessment of urban parks and forests to inform adaptive planning and management strategies that can maintain or enhance biodiversity.

A zoning-based solution for hierarchical forest patch mosaic in urban parks

Urbanization has led to the loss, fragmentation, and degradation of habitats, as well as that of biodiversity in cities. Urban parks play a key role in conserving biodiversity. Despite the advantages of complex vegetation structures for insect and bird diversity, a simple vegetation structure is favored in urban parks worldwide. The trade-off between human recreation and biodiversity conservation is challenging. Zoning strategy may be an effective countermeasure informed by the national park and natural scenic area; a zoning-based solution was introduced in this study, including preserved core zones and surrounding recreation zones. Guangyanggu Urban Forest Park was found to be advantageous for biodiversity and in terms of the feasibility of a small hierarchical forest patch (HFP) in the center of Beijing, which can serve as a model for core zones. The park had higher species richness of plants, insects, and birds than did six control sample parks. The Gleason richness indices of insect and bird species significantly correlated with the ratio of multilayered vegetation area to total sample area (r = 0.757 and 0.867 respectively; p < 0.05). The HFP mosaic model was used to develop the core zone in the urban park. Nine scenarios were defined for the HFP mosaic pattern, quantitatively delineating the typical spatial patterns of HFPs in parks. These results will improve the design and management of the current urban park paradigm. A bio-friendly park model characterized by HFP can optimize professional designing and maintenance guidelines for future urban parks.

Litter decomposition and infiltration capacities in soils of different tropical urban land covers

Healthy soil ecosystems are important for urban sustainability, because they provide the basis for ecosystem services such as flood regulation, nutrient cycling and carbon sequestration. We investigated the soils beneath five types of urban land cover in the tropical city of Singapore—secondary forest, managed grass, shrubs, trees, and trees with shrubs. We quantified the capacity of these soils to support two key ecosystem functions: litter decomposition, which we measured using a standardised tea bag method, and infiltration, which we measured using a double ring infiltrometer. Soil samples (0–20 cm depth) were collected from 120 sites and were analysed for 15 soil and vegetation properties including pH, soil organic matter content, particle size, bulk density and soil nitrogen, phosphorus and potassium. The forest sites had significantly higher leaf litter cover and canopy leaf area index than the other land cover types. Rates of litter decomposition and infiltration were highest in secondary forest, followed by trees with shrubs, and lowest in grass. Litter decomposition rates were positively related to soils with presence of soil invertebrate activity, leaf litter cover and soil nitrogen content. Infiltration rates were negatively related to soil bulk density. To optimise the delivery of soil ecosystem services in tropical cities, city managers and planners should protect any remaining fragments of forest, allow natural succession to occur, plant multi-layered vegetation with trees and shrubs, and restore urban soil by improving soil nutrients, reducing bulk density, and leaving leaf litter in situ.

Indigenous plants promote insect biodiversity in urban greenspaces.

The contribution of urban greenspaces to support biodiversity and provide benefits for people is increasingly recognized. However, ongoing management practices favor vegetation oversimplification, often limiting greenspaces to lawns and tree canopy rather than multi-layered vegetation that includes under- and midstorey, and the use of nonnative species. These practices hinder the potential of greenspaces to sustain indigenous biodiversity, particularly for taxa like insects that rely on plants for food and habitat. Yet, little is known about which plant species may maximize positive outcomes for taxonomically and functionally diverse insect communities in greenspaces. Additionally, while cities are expected to experience high rates of introductions, quantitative assessments of the relative occupancy of indigenous vs. introduced insect species in greenspace are rare, hindering understanding of how management may promote indigenous biodiversity while limiting the establishment of introduced insects. Using a hierarchically replicated study design across 15 public parks, we recorded occurrence data from 552 insect species on 133 plant species, differing in planting design element (lawn, midstorey, and tree canopy), midstorey growth form (forbs, lilioids, graminoids, and shrubs) and origin (nonnative, native, and indigenous), to assess (1) the relative contributions of indigenous and introduced insect species and (2) which plant species sustained the highest number of indigenous insects. We found that the insect community was overwhelmingly composed of indigenous rather than introduced species. Our findings further highlight the core role of multi-layered vegetation in sustaining high insect biodiversity in urban areas, with indigenous midstorey and canopy representing key elements to maintain rich and functionally diverse indigenous insect communities. Intriguingly, graminoids supported the highest indigenous insect richness across all studied growth forms by plant origin groups. Our work highlights the opportunity presented by indigenous understory and midstorey plants, particularly indigenous graminoids, in our study area to promote indigenous insect biodiversity in urban greenspaces. Our study provides a blueprint and stimulus for architects, engineers, developers, designers, and planners to incorporate into their practice plant species palettes that foster a larger presence of indigenous over regionally native or nonnative plant species, while incorporating a broader mixture of midstorey growth forms.

城市公园春季声景观与植被结构的关系

城市公园是城市生态系统的重要组成部分和城市生物多样性热点地区，具有丰富的声景观资源。由于声景观及声学方法具有信息量大，成本低，低侵入的特点，因此其研究和应用对生态系统健康及监测具有较高价值。声景观研究通过总结生物声的活动或多样性来衡量生物多样性。记录了北京20个城市公园的春季声景观，使用定量方法描述了声景观特征与变化；测试三种了已被证明与生物多样性相关并被广泛使用的声学指数（BIO、ADI、NDSI）与植被群落关系，完成了城市环境中声景观与环境关系的初步探究。研究结果表明：（1）声学指数能够有效表征城市公园声景观信息，具有显著的时间动态特性，能准确反映鸟类黎明合唱等重要生物生态活动；（2）声学强度指数也具有显著的时间动态变化和沿频率梯度的变化，不同的频率区间反映了不同声学群落的活动信息；（3）植被结构尤其是垂直结构对声景观起着重要作用，垂直异质性越大，声学多样性越高。发现支持声景观作为公园植被状况的度量，强调了其作为生物多样性和生态系统健康状况监测方法，用于城市管理和可持续发展的巨大潜力。;Urban foresters are addressing the challenges of urban biodiversity loss through management plans to adapt to urbanization. Protecting the integrity of the urban ecosystem requires long-term monitoring and planning for resilience as well as effective management. Urban parks are important parts of the urban ecosystem and hot spots of urban biodiversity, with rich soundscape resources. Due to the informative, low-cost, and low-impact features, soundscape-related researches and applications have a great potential of monitoring ecosystem health. Acoustic indices have been commonly used in soundscape ecology researches to measure biodiversity conditions by summarizing the activity or diversity of biological sounds. In this study, we recorded the soundscapes of 20 city parks within Beijing urban area in spring, trying to describe the characteristics and changes of soundscape quantificationally. A total of 23,040 minutes of sound materials were automatically sampled from raw data using Python. Then we calculated three widely used acoustic indices (BIO, ADI, NDSI) that have been proven to be related to biodiversity. The soundscape intensity index, power spectral density (PSD), was calculated to measure acoustic features along every frequency interval. All the indices' calculation is based on R studio. Spearman rho correlation analysis and principal component analysis were carried out to explore how environmental vegetation structures affecting soundscape in park habitats. The results show that (1) acoustic indices can not only effectively characterize the soundscape information of urban parks, but also have significantly time-dynamic characteristics, which can accurately reflect important biological activities and ecological processes such as bird dawn chorus. (2) The acoustic intensity index also reflects significantly temporal variations and changes along the frequency intervals. Different frequency interval groups reflect the corresponding activity information of acoustic communities. These results also provide more supports to the acoustic niche hypothesis (ANH) theory. (3) Our PCA modelling results show that the vegetation structure, especially the vertical structure, plays an important role in urban soundscapes. More vertical heterogeneity or multilayered vegetation, is associated with more acoustic diversity in urban parks. In the absence of historical soundscape data, we systematically collected and analyzed the soundscape of urban parks in Beijing. This is a pilot study for soundscape in Beijing urban parks. Our findings support soundscape as a measurement of habitat vegetation status and emphasize its great potential for urban management and sustainable development in biodiversity and ecosystem monitoring, which will enable regular assessment of urban parks and forests to inform adaptive planning and management strategies.

Impact of Partially Covered Vegetation on the Lateral Velocity Distribution of Open Channel Flow

The vegetation affects the flow process and water environment, thus drawing increasing attention to river environment management. Previous research is mainly focused on flow through vegetation in a channel with fully covered single-layer vegetation. However, in natural rivers, different heights’ vegetation often co-exists along one or two sides of a river. This paper experimentally studies how the flow velocity distribution is affected by the two different-layered vegetation allocated along two sides of an open-channel. The vegetation was simulated by dowels of two heights, 10 cm and 20 cm, and arranged in a parallel pattern along two sides of a flume under partially submerged conditions. The velocities along a cross-section were measured by Acoustic Doppler Velocimetry (ADV). The results of lateral velocity distribution show that a strong shear layer exists between vegetation and non-vegetation zones, indicating the retarding effect of vegetation. Meanwhile, as the flow depth increases, the relative velocity in the free flow zone decreases compared with that in the vegetated region, indicating that vegetation resistance to the flow decreases as increasing depth under the same vegetation configuration. These ?ndings would help understand the role of multi-layered vegetation in riparian management.

Unified Four-Stream Radiative Transfer Theory in the Optical-Thermal Domain with Consideration of Fluorescence for Multi-Layer Vegetation Canopies

Vegetation radiative transfer models (RTMs) are important tools to understand biosphere-atmosphere interactions. The four-stream theory has been successfully applied to solve the radiative transfer problems in homogeneous canopies for both incident solar radiation, thermal and fluorescence emission since 1984. In this note, we describe the development of a unified radiative transfer theory for optical scattering, thermal and fluorescence emission in multi-layer vegetation canopy, and provide a detailed mathematical derivation for the fluxes inside and leaving the canopy. This theory can be used to develop vegetation models for remote sensing applications and plant physiological processes, such as photosynthesis and transpiration. It can also be used to solve the radiative transfer problems in soil-water, soil-water-atmosphere, or soil-vegetation-atmosphere ensembles, besides the soil-vegetation system presented in the note.

Insect abundance in managed forests benefits from multi-layered vegetation

Retention forestry intends to promote biodiversity by retaining deadwood and tree-related microhabitats. Simultaneously, production forests undergo major structural changes by conversion into near-natural forests. As insect biomass is declining, it is important to understand how insect communities respond to management-related changes in forest structure. While some structural elements, such as deadwood, are studied extensively, three-dimensional forest structure is often neglected. Terrestrial laser scanning offers new approaches to quantify three-dimensional structure but their suitability has not been evaluated with field-based insect surveys.To test how insect communities respond to forest structure, we examined insects from window traps from 122 sites in the Black Forest. For total insect abundance and for the seven most abundant taxa, we related deadwood, microhabitats, various conventional stand properties and novel remote sensing-based indices for vegetation structure to total and taxon-specific abundances. Additionally, we assessed the influences of these structural elements on community composition.Total insect abundance and abundances of most taxa were positively related to multi-layered stands, as derived from remote sensing techniques. Furthermore, each taxon responded to some additional forest structural elements. Higher tree diameter, canopy gap fraction and share of deciduous trees increase abundances of the predominantly herbivorous taxa Heteroptera, Sternorrhyncha and Auchenorrhyncha. Community composition was influenced by mean tree diameter and share of deciduous trees. Neither tree-related microhabitats nor deadwood diversity had a detectable effect on insect abundance.We conclude that more elements of forest structure than previously acknowledged are related to insect populations. In particular, multi-layered forest stands have higher insect abundances in the midstorey. The current conversion in continuous-cover forestry in Europe from even-aged, often conifer-dominated forests to uneven-aged, mixed species stands can therefore increase the abundance of a wide range of insect taxa and is possibly one strategy to halt insect decline in forests.

Groundwater Management Based on Vulnerability to Contamination in the Tropical Karst Region of Guntur Spring, Gunungsewu Karst, Java Island, Indonesia

The purpose of this study was to examine the most suitable groundwater vulnerability method and formulate karst groundwater vulnerability management based on the distribution of the resulting vulnerability class. The most suitable groundwater vulnerability method was selected with a tracer test as well as by analysing its compatibility with the conditions of the study site, distribution of the vulnerability classes, spatial autocorrelation and comparison with other studies. The study was conducted on Guntur Spring, which is one of the tropical karst springs located in the western region of Gunungsewu Karst, Java Island, Indonesia. This perennial spring is used by approximately 1,000 people. This spring has the potential to be polluted due to the characteristics of the catchment area, which typify the connectivity between the surface and subsurface flow systems. The management of the Guntur Spring catchment was based on the distribution of vulnerability classes that are also adapted to the geomorphological, hydrogeological and land-use conditions. The analysis showed that EPIK is the most suitable method compared with COP, PI and PaPRIKa. The recommended management of the karst groundwater vulnerability included: (1) creating a protective structure at swallow holes; (2) reforestation and erosion management of thin soils on the crest of the karst hill; (3) addition of multilayer vegetation coverage to the upper, middle and bottom layers of the cockpit karst; (4) land-use and fertiliser limitations in the karst valley; and (5) restrictions on land use that produces pollutants around the lineaments, underground rivers and recharge points.

Soil Organic Matter Composition in Coastal and Continental Date Palm Systems: Insights from Tunisian Oases

In Tunisia, the coastal Chenini oasis is characterized by a lush vegetation cover, whereas more inland continental oases (e.g., the Guettaya oasis) have a very scarce vegetation cover. For sustaining date palm production in these areas, organic fertilizers are applied, either spread on the soil surface (in Chenini) or buried under a sand layer (in Guettaya). We examined at a molecular level how these management techniques affect soil organic matter composition in oasis systems. A dominance of fresh plant input for Guettaya was indicated by solid-state 13C nuclear magnetic resonance spectroscopy signals, which was most pronounced in the uppermost soil close to palms. Evidence for more degraded organic matter was found in deeper soil near the palms, as well as in the soil distant from the palms. Amino sugar contents were low in the uppermost Guettaya soil near the palms. The overall microbial amino sugar residue contents were similar in range as those found in other dryland environments. With increasing distance from trees, the amino sugar contents declined in Guettaya, where the palms grow on bare soil, but this was not the case for Chenini, which has multi-layer vegetation cover under palms. In agreement with the results from previous dryland studies, the soil microbial community in both oasis systems was dominated by fungi in topsoil, and a shift toward bacteria-derived residues in subsurface soil. This might be due to higher variability of temperature and moisture in topsoil and/or lower degradability of fungal remains; however, further research is required to confirm this hypothesis.

Effects of long-term landscape dynamics and city growth on biodiversity in the Mediterranean: the case study of Montpellier, France

In the Mediterranean, long-term land-use changes have resulted into landscape mosaics composed of very few ancient woodland remnants scattered across extended post-agricultural woodlands. Patches of ancient woodlands are now suffering rapid urban growth that reduces their area and impact their associated biodiversity. Here we use the case study of Montpellier, one of the most dynamic cities in France, to 1) characterize temporal changes in land covers (between 1860 and 2006) in its area, and 2) using two guilds of fungal bioindicators (i.e., polypores and lichens), to compare biodiversity stakes between ancient and secondary Mediterranean woodlands. We used a combination of historical maps, archives, fungal collections and field survey in eight Quercus ilex patches (4 ancient versus 4 recent replicates) to reconstruct landscapes dynamics and assess biodiversity changes. From the 19th to the 21st century, over half (52.4%) of the ancient woodlands within Montpellier were replaced by other land covers, mainly by urban equipment, while secondary patches (16.8% of the total area) were naturally established. Remaining ancient woodlands show multi-layered vegetation made of multi-secular Pinus halepensis dominating a dynamic understorey made of Quercus ilex and various Mediterranean shrubs. Polypores, but not macrolichens, tended to differ in community composition between ancient and recent woodland patches, with the highest diversity found in ancient woodlands. This study highlights that urban woodland patches of contrasted histories harbour distinct biodiversity stakes to be included in urban planning and provide valuable areas to evaluate biodiversity patterns and dynamics.

Linking crop structure, throughfall, soil surface conditions, runoff and soil detachment: 10 land uses analyzed in Northern Laos

In Montane Southeast Asia, deforestation and unsuitable combinations of crops and agricultural practices degrade soils at an unprecedented rate. Typically, smallholder farmers gain income from “available” land by replacing fallow or secondary forest by perennial crops. We aimed to understand how these practices increase or reduce soil erosion. Ten land uses were monitored in Northern Laos during the 2015 monsoon, using local farmers' fields. Experiments included plots of the conventional system (food crops and fallow), and land uses corresponding to new market opportunities (e.g. commercial tree plantations). Land uses were characterized by measuring plant cover and plant mean height per vegetation layer. Recorded meteorological variables included rainfall intensity, throughfall amount, throughfall kinetic energy (TKE), and raindrop size. Runoff coefficient, soil loss, and the percentage areas of soil surface types (free aggregates and gravel; crusts; macro-faunal, vegetal and pedestal features; plant litter) were derived from observations and measurements in 1-m2 micro-plots. Relationships between these variables were explored with multiple regression analyses. Our results indicate that TKE induces soil crusting and soil loss. By reducing rainfall infiltration, crusted area enhances runoff, which removes and transports soil particles detached by splash over non-crusted areas. TKE is lower under land uses reducing the velocity of raindrops and/or preventing an increase in their size. Optimal vegetation structures combine minimum height of the lowest layer (to reduce drop velocity at ground level) and maximum coverage (to intercept the largest amount of rainfall), as exemplified by broom grass (Thysanolaena latifolia). In contrast, high canopies with large leaves will increase TKE by enlarging raindrops, as exemplified by teak trees (Tectona grandis), unless a protective understorey exists under the trees. Policies that ban the burning of multi-layered vegetation structure under tree plantations should be enforced. Shade-tolerant shrubs and grasses with potential economic return could be promoted as understorey.

Why forest gardening for children? Swedish forest garden educators' ideas, purposes, and experiences

ABSTRACTUtilizing forest gardens as urban settings for outdoor environmental education in Sweden is a new practice. These forest gardens combine qualities of a forest, e.g., multi-layered polyculture vegetation, with those of a school garden, such as accessibility and food production. The study explores both the perceived qualities of forest gardens in comparison to other outdoor settings and forest garden educators' ideas, purposes, and experiences of activities in a three-year forest gardening project with primary school children. The data were collected through interviews and observations and analyzed qualitatively. Four reported ideas were to give children opportunities to: feel a sense of belonging to a whole; experience self-regulation and systemic dependence; experience that they can co-create with non-human organisms; and imagine possible transformation of places. Four pedagogical forest garden features are discussed.

Vegetation filtering algorithm for UAV-borne lidar point clouds: a case study in the middle-lower Yangtze River riparian zone

ABSTRACTA vegetation filtering algorithm is proposed for unmanned aerial vehicle (UAV)-borne lidar point clouds collected in the middle-lower Yangtze River riparian zone covered with multilayer and high-density vegetation. The proposed algorithm aims at generating digital elevation model, which consists of the following steps. First, multi-echo analysis is adopted for coarse filtering of point clouds. Then, morphological calculation is used to extract the ground seed points. Next, the trend surface of the local terrain is fitted. Meanwhile, the vegetation points are removed with the ground points preserved via random sample consensus. Experiments demonstrate that the performances of the algorithm were more accurate than Terrasolid’s TerraScan when dealing with UAV-borne lidar point clouds in limited sample of a multilayer and high-density vegetation covering areas. The research results also show that by using a special filtering approach it is possible to classify laser points into terrain and vegetation automatically even for thoroughly mixed vegetation and terrain points and penetration rate of below 15%.