Suburban Forest Research Articles

First use of Chironomid Pupal Exuvial Technique in freshwater biomonitoring in Cameroon: Ecological aspect and morphological description of Chironomidae (Insecta: Diptera)

The biodiversity of urban streams is gradually degrading as a result of anthropogenic pollution. In this study, chironomid pupal exuviae were used as surrogates to assess urban streams and a lake in Douala Cameroon. We compared these assessments with samples collected from a suburban forest stream. Based on their highly adaptive capability, we predicted that chironomid communities would present high diversity and abundance in urban habitats. Chironomid pupal exuviae were collected using the chironomid pupal exuvial technique in 14 urban and 2 forest reference stations during dry and rainy seasons. Measurements of the environmental variables were done simultaneously. Physicochemical analysis revealed that all urban sites have had very poor ecological health status whereas forest site had good water quality as shown by the hierarchical cluster analysis. This ecological survey identified 8 species/morphotypes of chironomids all belonging to the subfamily Chironominae, tribe Chironomini. These are Chironomus holomelas(?), Chironomus sp.1, Chironomus sp.2, Chironomus sp.3, Chironomus (Lobochironomus) sp., Stenochironomus sp., Dicrotendipes sp. and Dicrotendipes pulsus. No midge pupal exuviae were recorded at the forest stations (S1 & S2) and the stations S6 and S7 located downstream industrial mill effluents. The species richness of the study sites was significantly very low as compare to other Afrotropical studies. Canonical redundancy analysis revealed that high values of water temperature, ammonium, nitrates and phosphates, and low oxygen concentration were significant predictors of the distribution and high abundance of Chironomidae. This survey highlighted the impacts of anthropogenic activities on chironomid diversity and distribution, with great decrease of their diversity due to industrial pollution.

The use of digital tools in forest tourism and recreation - Experiences from Warsaw agglomeration in Poland

Tourism and recreation in forest areas around large urban agglomerations are becoming increasingly important and pose major management challenges in terms of sustainability, environmental impact and balancing the needs of visitors with conservation efforts. Digital tools are critical to the planning and management of suburban forests as they improve data collection, enable efficient resource allocation and enhance the visitor experience through better navigation and information dissemination. The aim of our work was to find out whether people visiting urban and suburban forests in Warsaw consciously plan their visits to forest areas, what ICT tools they use during and after a forest visit, and whether they share their experiences related to forest recreation on social media after the visit. The research focused on urban and suburban forests in the Warsaw metropolitan area, Poland. Data on visitors’ characteristics, recreation habits and digital skills were collected in an online panel survey in November 2023 (n = 1413). The results showed that respondents most frequently visited forest areas around Warsaw 2–3 times a month and several times a year. The vast majority of respondents planned their visits directly on the day of the trip (34.96 %) and used their own knowledge and experience when planning their trip to the forest. More than half of respondents (69 %) stated that they use various types of digital tools when visiting forest areas, most commonly smartphones with GPS functionality. Most respondents stated that they had advanced (43.38 %) or at least advanced (32.06 %) knowledge of using digital tools. 39.49 % of respondents stated that they do not use the internet to share information about their forest visits. The research results presented in the sentence indicate the complexity of using digital tools in the management of outdoor recreation and tourism. On the one hand, our research clearly shows that digital tools are an integral part of modern outdoor recreation and tourism management and provide valuable insights, on the other hand, most respondents planned their visits directly on the day of departure, relying mainly on their own knowledge and experience, rather than on digital tools. This knowledge can be used to develop forest management strategies, environmental education, monitoring tourist flows and promoting responsible recreation worldwide. Further research is needed to analyse the use of digital tools in digital forest recreation.

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

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

Recreation in suburban forests – monitoring the distribution of visits using the example of Rzeszów

Recreation in suburban forests – monitoring the distribution of visits using the example of Rzeszów

Edaphic factors mediate the responses of forest soil respiration and its components to nitrogen deposition along an urban-rural gradient

Exploring the influences of nitrogen deposition on soil carbon (C) flux is necessary for predicting C cycling processes; however, few studies have investigated the effects of nitrogen deposition on soil respiration (Rs), autotrophic respiration (Ra) and heterotrophic respiration (Rh) across urban-rural forests. In this study, a 4-year simulated nitrogen deposition experiment was conducted by treating the experimental plots with 0, 50, or 100 kg·ha−1·year−1 of nitrogen to check out the mechanisms of nitrogen deposition on Rs, Ra, and Rh in urban-rural forests. Our finding indicated a positive association between soil temperature and Rs. Soil temperature sensitivity was significantly suppressed in the experimental plots treated with 100 kg·ha−1·year−1 of nitrogen only in terms of the urban forest Rs and Ra and the rural forest Ra. Nitrogen treatment did not significantly increase Rs and had different influencing mechanisms. In urban forests, nitrogen addition contributed to Rh by increasing soil microbial biomass nitrogen and inhibited Ra by increasing soil ammonium‑nitrogen concentration. In suburban forests, the lack of response of Rh under nitrogen addition was due to the combined effects of soil ammonium‑nitrogen and microbial biomass nitrogen; the indirect effects from nitrate‑nitrogen also contributed to a divergent effect on Ra. In rural forests, the soil pH, dissolved organic C, fine root biomass, and microbial biomass C concentration were the main factors mediating Rs and its components. In summary, the current rate of nitrogen deposition is unlikely to result in significant increases in soil C release in urban-rural forests, high nitrogen deposition is beneficial for reducing the temperature sensitivity of Rs in urban forests. The findings grant a groundwork for predicting responses of forest soil C cycling to global change in the context of urban expansion.

Vertical gradient of needle ozone uptake within the canopy of Cryptomeria japonica

Leaf ozone uptake through the stomata is an important index for the ozone risk assessments on trees. Stomatal conductance (gs) and ozone concentration ([O3]), determinants of the leaf ozone uptake, are known to show vertical gradients within a tree canopy. However, less is known about the within-canopy vertical gradient of leaf ozone uptake. This study was aimed to elucidate how the vertical gradient of [O3] and gs affect needle ozone uptake within a canopy of mature Cryptomeria japonica trees in a suburban forest at Tokyo, Japan. For this purpose, a multilayer gas exchange model was applied to estimate the vertical gradient of needle gs and the accumulated ozone uptake during the study period (POD1, Phytotoxic Ozone Dose above a threshold of 1 nmol m−2 s−1). In addition, we also tested several scenarios of vertical gradient of [O3] within the canopy for sensitivity analysis. The POD1 was declined from the top to the bottom of the canopy. This tendency strongly depended on the vertical gradient of gs and was hardly affected by the changes in simulated vertical reductions of the [O3]. We further assessed the photosynthesis of sunlit needles (needles absorbing both direct and diffuse light) and shaded needles (needles only absorbing diffuse light). The photosynthesis of shaded needles in the upper half of the canopy made a great contribution to the entire canopy photosynthesis. In addition, given that their POD1 was lower than that of sunlit needles, ozone may affect sunlit and shaded needles differently. We concluded that these considerations should be incorporated into modeling of the calculation of ozone uptake for mature trees to make accurate predictions of the ozone effects on trees at the canopy scale.

Post-fire soil erosion: Two years of monitoring − First time detected implications between extremely intense consecutive rainfall events and erosion rates

The research was carried out in one of the most important suburban forests of Greece, after a wildfire (2021). The objectives include the estimation of the annual soil erosion, the effect of extremely intense and consecutive rainfalls on erosion process, the correlation among erosion, rainfall intensity and other factors. To monitor soil erosion in burned and unburned areas, erosion measurements were obtained installing silt fences. The results showed that the main factor affecting annual erosion is the presence or not of vegetation. Rainfall intensity is a major determinant of erosion, especially when it exceeds 6–7 mm/30 min. However, it was revealed that erosion does not increase significantly in burned areas, despite the increase of rainfall intensity. In unburned area the erosion was significantly increased, above a rainfall intensity threshold (>10 mm/30 min). For the first time, it was shown that in cases of two consecutive and very heavy rainfalls, the second and more intense rain caused significantly lower erosion than the first one. A 690 % average increase in R factor during the 2nd storm, showed an average decrease in soil erosion of 20 % (burned and unburned areas). The present study also revealed that the high increase of R factor in the 2nd post-fire year did not trigger a significant increase of soil erosion, since the extreme erosive events occurred very close to each other in time. These findings highlight that the use of R factor in RUSLE, to calculate the annual erosion in burned or unburned areas, detached from the respective field data establishment to validate the model, involves high uncertainties, which could possibly result in wrong erosion rates calculations. Researches and stakeholders, who use the R factor in erosion modeling, should previously examine in detail the exact dates of erosive events, before the implementation of the erosion model.

Characterisation of particle single-scattering albedo with a modified airborne dual-wavelength CAPS monitor

Abstract. Atmospheric aerosols impact the Earth's climate system directly by scattering and absorbing solar radiation, and it is important to characterise the aerosol optical properties in detail. This study reports the development and validation of an airborne dual-wavelength cavity-attenuated phase-shift (CAPS) single monitor, named A2S2 (Aerosol Absorption Spectral Sizer), based on the commercial CAPS single-scattering albedo monitor (CAPS-PMSSA; Aerodyne), to simultaneously measure the aerosol optical scattering and extinction at both 450 and 630 nm wavelengths. Replaced pressure and temperature sensors and an additional flow control system were incorporated into the A2S2 for its utilisation on board research aircraft measuring within the troposphere. The evaluation of A2S2 characteristics was performed in the laboratory and included the investigation of the signal-to-noise ratio, validation of performance at various pressure levels, optical closure studies and intercomparing with the currently validated techniques. The chamber experiments show that the A2S2 can perform measurements at sample pressures as low as 550 hPa and at sample temperatures as high as 315 K. Based on the Allan analysis results, we have evaluated that the minimum detection limit of the measurements shows that the measurements have a limit accuracy of ∼ 2 Mm−1 at 450 nm and ∼ 1 Mm−1 at 630 nm for 1 Hz measurements of both scattering coefficients (σsca) and extinction coefficients (σext). The optical closure study with size-selected polystyrene latex (PSL) particles shows that the truncation error of the A2S2 is negligible for particles with particle volume diameter (Dp) < 200 nm, while, for the larger sub-micrometre particles, the measurement uncertainty of A2S2 increases but remains less than 20 %. The average factors to correct the truncation error are 1.13 and 1.05 for 450 and 630 nm, respectively. A simplified truncation correction, dependent on the scattering Ångström exponent (SAE), was developed to rectify truncation errors of the future A2S2 field measurement data. The σsca and σext measured by the A2S2 show good agreement with the concurrent measured results from the nephelometer and the CAPS particle extinction monitor (CAPS-PMex). The absorption coefficient (σabs) derived through the extinction-minus-scattering (EMS) method by the A2S2 also corresponds with the results obtained from the aethalometer. The A2S2 was successfully deployed during an aircraft measurement campaign (Atmospheric ChemistRy Of the Suburban foreSt – ACROSS) conducted in the vicinity of Paris and the surrounding regions. The average SSA measured during the entire ACROSS flight campaign is 0.86 and 0.88 at 450 and 630 nm, respectively, suggesting that light-absorbing organic aerosols play a significant role. The average SAE and absorption Ångström exponent (AAE) varied due to measurements in various pollution conditions. The results presented in this study indicate that the A2S2 instrument is reliable for measuring aerosol σsca and σext at both blue and red wavelengths, and it stands as a viable substitute for future airborne evaluations of aerosol optical properties.

An Assessment of Landscape Perception Using a Normalised Naturalness Index in the Greater Seoul Area

This study analysed the greater Seoul area (GSA) in terms of naturalness, a representative indicator of natural scenic beauty, and created an assessment map, shifting from a traditional urban development perspective to a landscape perspective. It also developed a “normalised naturalness index” by combining the results of the expert metric score with the Hemeroby index, which was used as a naturalness assessment representative item. Then, it interpreted the naturalness status of the GSA landscape characteristics. As a result, the landscape of the GSA demonstrates the following five characteristics: First, the central business districts in the capital city of Seoul are densely developed areas with a very high degree of human intervention. Second, the satellite cities built to solve Seoul’s housing and logistics problems are rated as “a little less, but still heavily humanised” as a landscape characteristic. These areas are becoming increasingly humanised. Also, it is worth noting that the third characteristic, regarding moderate landscape areas, has a distinctly different meaning for areas outside of the city boundary, as well as those within the city boundary. Although these areas are in the same statistical category, they have two different meanings: one is the area where the average values converged on “moderate” by virtue of urban forests near the city centre, and the other is the area outside of Seoul that has a Hemeroby value of 0.5–0.6, which refers to open spaces such as agricultural lands, wetlands, or coastal areas. Fourth, suburban forests are reserved with legal restrictions to curb excessive urban sprawl, as well as parts of the demilitarised zone along the border areas of North and South Koreas. The last landscape characteristic is illustrated in the scenic area of the eastern woodlands. The normalised landscape naturalness index developed through this study provides an overall understanding of the environmental state of the GSA. Future research may build on the results of this study to refine methods for assessing public perceptions of naturalness.

Long-term effects of biochar application on biological nitrogen fixation of acacia species and soil carbon and nitrogen pools in an Australian subtropical native forest

PurposeBiological nitrogen (N) fixation (BNF) of understory acacia species presents a potential way for effectively restoring N in forest systems. This study aimed to quantify the impact of acacia species and biochar application rates on BNF and soil mineral N in a suburban native forest of subtropical Australia in the first 4–5 years after prescribed burning.MethodPlant growth values and BNF were measured to assess the impact of biochar rates at 0, 5, and 10 t ha−1 on different acacia species. Soil NH4+-N and NO3−-N along with their N isotope composition (δ15N) were determined to investigate soil–plant interactions in response to acacia species and biochar application.ResultsThe application of 10 t ha−1 biochar significantly enhanced the growth of acacia species, and concurrently reduced the loss of NO3−-N at soil depths of 0–5 and 5–10 cm. Compared with Acacia disparimma (percentage of N derived from the atmosphere or %Ndfa: 78.2%), A. leiocalyx demonstrated significant higher BNF ability (%Ndfa: 91.3%). Similarly, A. leiocalyx had better growth, in terms of height (269.1 cm versus 179.6 cm), diameter at ground level (2.62 cm versus 1.94 cm), basal area (6.49 cm2 versus 3.43 cm2) and volume (692.2 cm3 versus 258.0 cm3). This was associated with its ability to promote organic matter mineralization, resulting in the accumulation of 15N-depleted NH4+-N. NH4+-N, acting as a substrate, was transformed into NO3−-N through nitrification. From regression analysis, the efficient absorption of NH4+-N by A. leiocalyx significantly mitigated NH4+-N leaching with increasing soil moisture concentration (SMC), resulting in lower δ15N of NH4+-N, which was more negatively related to SMC (R2 = 0.401), compared to that of A. disparimma (R2 = 0.250) at soil depth of 0–5 cm. The production of NO3−-N was reduced, leading to lower NO3−-N concentrations of A. leiocalyx than A. disparimma at soil depth of 0–5 cm (8.06 µg N g−1 versus 9.61 µg N g−1) and that of 5–10 cm (8.24 µg N g−1 versus 9.21 µg N g−1) respectively.ConclusionsAs an effective soil amendment, biochar exhibited promise in reducing mineral N loss and stimulating plant growth in long-term applications of exceeding three years. Higher BNF capacity and greater plant growth were observed with A. leiocalyx, compared with those of A. disparimma. The retention and utilisation of mineral N by A. leiocalyx can be considered as strategy to restore forest soils.

Biochar application for enhancing water and nitrogen use efficiency of understory acacia species in a suburban native forest subjected to nitrogen deposition in Southeast Queensland

Abstract Purpose The fuel reduction prescribed burning and biochar application can have significant impacts on water and nitrogen (N) use efficiency of understory acacia species as well as soil carbon (C) and N pools in a suburban native forest subject to N deposition in Southeast Queensland, Australia. Methods We evaluated the impact of biochar application rates (0, 5.0 and 10.0 t biochar per hectare) and prescribed burning on soil-plant interactions in carbon (C) and N cycling in a suburban native forest in the first two years of biochar application or three and half years of the recently prescribed burning. Results Anthropogenic N deposition not only enhanced N losses caused by N leaching and denitrification, but also inhibited biological N fixation (BNF) by increasing N availability in forest systems. The Acacia leiocalyx with higher water use efficiency was more inclined to utilize easily available N resources (from N deposition), compared with A. disparismma. In this study, biochar application could indeed reduce N loss in forest soil and improve soil fertility by improving plant water and N use efficiency. Meanwhile, soil moisture content affected by biochar application also influenced soil N transformations by affecting soil microbial activity. Conclusion For urban forest soils, the high N availability caused by N deposition could inhibit the BNF in a suburban native forest ecosystem. The high-porosity physical structure of biochar applied increased the soil water content and soil N retention capacity.

Ecological Risk Assessment, Distribution and Source of Polycyclic Aromatic Hydrocarbons in the Soil of Urban and Suburban Forest Areas of Southern Poland

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that can pose a risk to people living near contaminated soils. The role of forest ecosystems around urban agglomerations as a draw to urban dwellers has been highlighted by the COVID-19 pandemic. The pandemic led us to focus this study on the soils beneath forested areas around urban agglomerations, with the aim of assessing the sources and ecological risk of PAHs in the soils. For the study, a 150 km transect was delineated by six sampling sites, located in urban and commercial forests, which were characterised by the same species composition. Samples were taken from the 0–10 cm depth horizon, after removal of the organic layer. The content of 16 PAHs was determined, from which the potential source of contamination, the toxic equivalent quotient (TEQ), the potential ecological risk quotient (RQ) and the incremental lifetime cancer risk quotient (ILCR) were calculated. The mean sums of the PAHs ranged from 12.41 to 52.76 μg·kg−1. Our analysis indicated that the share of pollutants in the soils had resulted from industrial combustion, biomass and coal combustion, and traffic. The RQ of the PAHs in the soils of the Upper Silesian Industrial Region, or within its impact range, were found to be low to moderate. High ILCR ratios for children (1.9 × 10−4) and adults (8.38 × 10−5) were recorded in soils related to a refinery. Our findings confirm that forests around urban areas are vulnerable to pollution. People living in cities should consider spending their leisure time in forest areas at a distance from their homes. Systematic and continuous monitoring of PAHs is necessary to ensure that human safety is guaranteed.

Analysis of patterns of light interception by the crowns of Cotoneaster lucidus Schlecht bushes in various ontogenetic states in the Kalinovsky Forest Park of Yekaterinburg

In the forest park area of Yekaterinburg Cotoneaster lucidus Schlecht. found as a naturalized introduced species in various forms of plantings. With increasing anthropogenic pressure on suburban forests, it is important to study the biological characteristics of invasive species and their intraspecific differentiation to preserve the gene pool, therefore, studying the patterns of manifestation of the size, ontogenetic and structural parameters of cotoneaster in coenopopulations makes it possible to identify the peculiarities of the dynamics of their development and give a complete picture of the processes of adaptation of this species to the conditions growth. The article studied the lighting parameters in different parts of the crowns of C. Lucidus bushes of various ontogenetic states, and analyzed their ability to intercept light. The parameters of lighting and its interception largely depend on the structural features and size of the crowns of bushes, their age and ontogenetic state. With age (transition to later ontogenetic states), the parameter of illumination received above the crown increases, the interception of illumination by entire crowns of bushes increases from 33.2% for j to 68.4% in the late generative state (at the same time, the interception of illumination by the lower parts of the crowns is relatively stable, varying from 10.7% to 16.7%), the correlation between the parameters of illumination and its interception in different parts of the crown becomes less pronounced. The latter is associated with the development of an increasingly complex and dense structure in the volume of the crowns of C. lucidus bushes.

Таксационная характеристика особенностей лесного фонда Барнаульского лесничества Алтайского края

The study was conducted in order to identify forestry and taxation features of forest plantations in the Barnaul forestry of the Altai Territory, located in the suburban area of Barnaul. Areas of the forest fund were selected at different distances from the city of Barnaul: in the zone of a dense network of roads and settlements (0‑15 km) and in the zone of less intensive infrastructure (37 km). Using the methods of ecological profiles, variation statistics, comparative analysis, and forest taxation, the taxation materials of 32 forest quarters were processed, including data from 718 forest taxation allotments. Using two-factor analysis of variance, it was found that the individual studied indicators of forest plantations (average height, completeness, bonus class and reserve per 1 ha) depend on the type of forest. The taxation indicators of stands in the suburban area (except for the average stock per 1 ha) do not have a reliable dependence on the features of Barnaul. The analysiso f variance in relation to the natural renewal of the main breed showed that the average height and density depend on the type of forest, and the distance from the city limits affects only the average density. High vaul es of occurrence (65.4‑89.5%) of undergrowth were noted in fresh forest, lower in grass forest (15.5‑48.4%), but the occurrence increases with distance from the city in both types of forest. Ash-leaved maple finds its ecological niche mainly in the grass forest, displacing local plant species, preventing the natural renewal of pine. It has been previously established that the parameters of forest plantations in suburban pine forests of Barnaul depend on the type of forest, showing different structural and positional stability in relation to anthropogenic factors.

ГОРОЖАНИН И ПАРК: ПОВСЕДНЕВНЫЕ ПРАКТИКИ ВЗАИМОДЕЙСТВИЯ С ПРИРОДОЙ НА ПРИМЕРЕ СОВЕТСКОГО ЧЕЛЯБИНСКА

The article considers the formation of urbanized practices in green spaces using the example of soviet Chelyabinsk. In the 1930s–1960s, Chelyabinsk was a fast-growing industrial city, where a large relict pine forest was preserved. For soviet managers and new city dwellers, the forest became a “testing ground” for mastering new practices of interaction with nature in conditions of accelerated urbanization. Especially when in the 1930s a part of the forest was repurposed into the Park of Culture and Recreation. Based on archived and journalistic materials, it is shown that the semantic and functional distinction between the park and the forest led to the formation of two types of practices of interaction between city residents and nature. Contrasting the park with the forest, party leaders insisted on the development of infrastructure for the “cultural”, “organized” recreation of new Soviet citizens, while the forest became a space for interaction with the natural world unregulated by the authorities. During the 1960s the forests public image transformed, from a wild suburban forest to a fragment of pristine nature, miraculously surviving in an industrial city, with the Park of Culture and Recreation forming the “grand entrance”. It is concluded that urban practices of interaction with nature developed in two ways. The first is the “acculturation” of the forest area through political actions to establish an ideologically approved recreation for new citizens. The second way was constituted by the formation of citizens’ ecological consciousness in the context of a greenery deficit in the industrial areas of the city.

The impacts of nitrogen addition on the active carbon pools in forest soils along an urban–rural gradient

The increased nitrogen (N) deposition accompanying urbanization alters the dynamics of soil carbon (C) in urban and peri-urban forests. However, our understanding of the magnitude and mechanism of this impact is still minimal. In this study, experimental plots were established in urban, suburban, and rural forests to investigate the effects of three levels of N addition: no addition (0), low addition (50 kg N·ha−1·yr−1), and high addition (100 kg N·ha−1·yr−1). The responses of the active components in the soil C pool, including dissolved organic C (DOC) and microbial biomass C (MBC), were monitored after simulated N deposition treatments in forests along an urban–rural gradient. The results showed that the concentrations of DOC and MBC in forest soils along the urban–rural gradient exhibited significant seasonal and site variation. Soil DOC and MBC concentrations in the rural forest were significantly affected by N addition, increasing by 13.39 % and 45.90 % under the low N treatment, respectively, and MBC concentration increased by 28.40 % under the high N treatment. On the contrary, soil DOC and MBC concentrations in urban and suburban forests did not change significantly. Among studied influencing factors, the total dissolved N provided the crucial nutrient sources for microbial growth and activity and thus became the primary factor affecting the active components in the soil C pool. The insensitivity of urban and suburban forests' active soil C pools to added N indicates that the N fertilization effect brought by urban expansion may not have a lasting impact on soil C pools of rural forests.

Structure of Collembola Communities in the Urban Gradient of Rīga City

Abstract The world’s increasing urbanisation and the deterioration of human quality of life in major cities have redirected the focus of urban planning toward green infrastructure improvement and, as a result, increased the research of urban ecosystems. This article analyses changes in the structure of Collembola communities in soil in the urban-rural gradient in the city of Rīga, Latvia. Soil samples were collected in 21 randomly selected sample plots within six urban habitats: street edge grasslands, downtown parks, private houses, cemetery grasslands, and urban and suburban forests. Soil samples were taken at the end of September/beginning of October 2017. A steel soil corer (D 50 mm, surface area 19.6 cm2, depth 10 cm) was used. In each plot, three soil samples were taken with a soil corer. Collembola were extracted from pooled samples from each habitat using a Berlese-Tullgren extractor. Nonmetric Multidimensional Scaling (NMS) ordination of Collembola data in sample plots yielded three statistically significant axes (p < 0.01). The first axis explaining 49% of the data variation coincided with the urban-rural gradient. Species richness declined towards the city centre, while the Simpson’s Dominance Index increased. The species Mesaphorura macrochaeta predominates in the central habitats, while Parisotoma notabilis dominates in suburban forests.

Bioecological analysis of the flora of suburban and urban forests of Samara

The article presents the results of the study and analysis of the flora of the forests of suburban and urban forests of Samara. 279 plant species have been identified in the study area, among which only five are rare and protected at the regional level (Campanula latifolia L., Fritillaria ruthenica Wikstr., Tulipa biebersteiniana Schult. et Schult. fil., Cephalanthera rubra (L.) Rich., Pulsatilla patens (L.) Mill.). In the spectrum of life forms, trees are represented by 24 species, shrubs – by 23 species. Among herbaceous perennials, the rhizomatous group of plants predominates – 57 species, or 20,4%. In the group of juveniles, numbering 68 species, or 24,3%, annuals predominate – 41 species, or 14,6% of the total flora. In the surveyed forests, the forest group of plants naturally dominates among the phytocoenotypes – 71 species, which is 25,4% of the total flora. The ecological group of mesophytes, being the leading one, includes 184 plant species, which makes up 65,9% of the flora. The analysis of the flora showed a significant proportion of weed-ruderal representatives. Indigenous oak-linden forests currently retain their positions in the region, however, maple forests occupy a significant territory among them. The anthropogenic factor (recreation, fires, clearings) has a significant impact on the floristic complex. Recreation and forest fires in some cases are the main reason for the transformation of forest plant communities in the territory of Samara and its suburbs.

Landscape Health Assessment of Suburban Forest Park: A Case Study Based on Multiple Sampling Units and Functional Characteristics

Assessing the landscape health of suburban forest parks is a prerequisite for achieving the dual objectives of forest resource conservation and recreational services. However, studies that analyze landscape health in suburban forest parks at a landscape scale by subdividing the landscape into multiple sampling units and adopting a multi-functional perspective have been limited. This study focuses on Xiqiao Mountain National Forest Park and establishes a landscape classification system and indices, taking into account its multifunctionalities. The study employs the entropy weight method to determine indicator weights and utilizes grid analysis and spatial interpolation to analyze the spatial distribution of landscape health under multiple sampling units and functionalities, along with the differences in its impact and influencing factors. The results indicate that: (1) regions with “very poor” and “poor” landscape health grades under multiple sampling units and functionalities exhibited a sheet-like distribution pattern, covering approximately 69.46% to 98.86% of the total area. In contrast, regions with “very good” and “good” grades are primarily located in block-like or linear patterns in the northern, central, and southern regions of the park, accounting for approximately 1.07% to 17.20% of the total area. (2) The area ratios of “very good” and “good” landscape health grades for recreational landscapes under varying sampling units were consistently higher than those of the same grades for eco-conservational landscapes, with a 5.03%–15.43% difference. This suggests a greater emphasis on recreational functionality. (3) The impact of three different sampling unit sizes on the landscape health of Xiqiao Mountain National Forest Park under multifunctionalities is not significantly different; however, the forest/non-forest area ratio and quantity ratio are vital factors influencing its landscape health. The landscape health assessment results, considering multiple sampling units and functionalities in this study, serve to provide technical method support and practical case references for the planning, construction, and management decision-making of suburban forest parks.

Suburban forest patches have high functional and phylogenetic diversity in bird communities

Suburban forest patches have high functional and phylogenetic diversity in bird communities