Species In Landscapes Research Articles

Diverse and larger tree islands promote native tree diversity in oil palm landscapes.

In monoculture-dominated landscapes, recovering biodiversity is a priority, but effective restoration strategies have yet to be identified. In this study, we experimentally tested passive and active restoration strategies to recover taxonomic, phylogenetic, and functional diversity of woody plants within 52 tree islands established in an oil palm landscape. Large tree islands and higher initial planted diversity catalyzed diversity recovery, particularly functional diversity at the landscape level. At the local scale, results demonstrated that greater initial planting diversity begets greater diversity of native recruits, overcoming limitations of natural recruitment in highly modified landscapes. Establishing large and diverse tree islands is crucial for safeguarding rare, endemic, and forest-associated species in oil palm landscapes.

A chromosome-level genome assembly of the mountain lion, Puma concolor.

Mountain lions, Puma concolor, are widespread and adaptable carnivores. However, due to their large home ranges and long distance dispersals, they are strongly impacted by habitat fragmentation, which results in small and isolated populations. Genomic analyses play an important role in understanding and predicting the impacts of increased isolation of populations, such as decreased genetic diversity and increased levels of inbreeding. Here we report a high-quality, chromosome-level reference genome of P. concolor that was generated as part of the California Conservation Genomics Project. The primary assembly has a total length of 2.5 Gb contained in 258 scaffolds, a contig N50 of 42.3Mb, a scaffold N50 of 149.8Mb, and a BUSCO completeness score of 95%. This P. concolor genome assembly will provide an important resource for genomic analyses that aid decision makers in managing the species in fragmented landscapes.

Effects of Breeding Habitat on the Abundance and Body Condition of Two <i>Pelophylax</i> Species in Agriculture and Urban Landscapes

Amphibians play a key role in structuring biological assemblages of agricultural landscapes, but they are threatened globally by agricultural intensification. Numerous studies have considered the morphology of animals to be an indicator of the health of a population, but data about the differences in amphibian morphology in different breeding habitats in agricultural landscapes are still missing. Here, we investigated the differences in the abundance and morphology of Pelophylax plancyi and Pelophylax nigromaculatus in the three waterbody types: fields, forests, and parks in agricultural landscapes in Nanjing, China. Our results emphasize that both frog species in forests and parks had significantly higher body condition indexes than those in fields, whereas their abundance in fields habitat was higher than those of the two other habitat types. Our results demonstrated the importance of non-agricultural habitats (such as forests and parks) in agricultural landscapes to the persistence of both Pelophylax species. We recommend preserving field ecosystems by constructing diverse waterbodies other than fields in rural areas and maintaining microhabitats in parks and forests to improve amphibian biodiversity in Nanjing.

Mapping forest tree species and its biodiversity using EnMAP hyperspectral data along with Sentinel-2 temporal data: An approach of tree species classification and diversity indices

Forests play a crucial role in maintaining ecological balance and biodiversity, making the accurate mapping of tree species and assessment of biodiversity indices essential for informed management decisions. This study introduces an innovative methodology that integrates EnMAP (Environmental Mapping and Analysis Program) hyperspectral data with Sentinel-2 multitemporal data to classify tree species in the biodiverse landscapes of Kampinos National Park and its surrounding regions in Poland.We extract essential vegetation indices such as NDVI, NDMI, SAVI, and EVI from Sentinel-2 data to assess forest health and dynamics. The Sentinel-2 data is upscaled from 10 m to 30 m to align with EnMAP’s spatial resolution, followed by precise co-registration of the images using QGIS. Utilizing a rich dataset from the National Forest Inventory, we extract spectral signatures of nine distinct tree species from both data sources. We employ five machine learning algorithms—Support Vector Machines (SVM), Random Forest (RF), CatBoost (CAT), Gradient Boosting Classifier (GBC), and XGBoost (XGB)—to enhance classification accuracy.Through iterative experimentation with data reduction techniques and algorithm tuning, we achieve optimal performance across needle-leaved and broad-leaved species. The resulting tree species maps are validated through quantitative accuracy assessments against mixed-species polygons from the National Forest Inventory and ground truthing in the Kampinos National Park. Achieving an overall accuracy of 85% to 93%, our study demonstrates the efficacy of this integrated approach in tree species mapping. Furthermore, the tree species maps serve as a foundation for deriving key biodiversity indices—species richness, Shannon-Wiener Diversity Index, Simpson’s Diversity Index, and a composite Biodiversity Index—providing insights into spatial biodiversity patterns and informing targeted conservation strategies. This study exemplifies the potential of combining advanced remote sensing techniques with field validation to enhance our understanding of forest ecosystems and guide sustainable management practices.

Drivers of Wolf Activity in a Human-Dominated Landscape and Its Individual Variability Toward Anthropogenic Disturbance.

Wolves (Canis lupus) exhibit contrasted activity patterns along their distribution range. The shift from diurnal to nocturnal habits within and among populations appears to be primarily driven by localized levels of human activity, with ambivalent responses toward such disturbance reported among populations. Yet, the drivers and the underlying individual variability of temporal avoidance patterns toward human remains unexplored. We equipped 26 wolves with GPS-GSM collars, obtaining 54,721 locations. We used step lengths, turning angles, and accelerometer data from recorded locations to infer activity through hidden Markov models (Conners, M. G., T. Michelot, E. I. Heywood, et al. 2021. "Hidden Markov Models Identify Major Movement Modes in Accelerometer and Magnetometer Data From Four Albatross Species." Movement Ecology 9, no. 1: 1-16.). We further explored the probability of activity as a function of a set of proxies of anthropogenic disturbance at different spatial scales and its interaction with different periods of the day by fitting population-level and individual-based hidden Markov models. Wolves were predominantly active during dusk and night, yet variations in activity emerged among individuals across day periods. We did not find clear population-level effects of anthropogenic disturbance predictors, as these were masked by a wide range of individual-specific responses, which varied from positive to negative, with inter-individual variability in responses changing according to different predictors and periods of the day. Our results suggest a non-uniform strategy of wolves in adapting their behavior to human-dominated environments, further underscoring the role of vegetation patches acting as functional refuge cover for buffering the effects of anthropogenic disturbance and boosting the persistence of the species in human-dominated landscapes. This study, for the first time, reveals the individual variability in wolf responses to human disturbance. By fitting hidden Markov models to data from GPS-GSM collars deployed on 26 wolves, we found significant variation between individuals in their responses to different levels of anthropogenic pressure and across different times of day, highlighting a non-uniform strategy for coping with perturbations in human-dominated landscapes. Our findings underscore the diverse behavioral adjustments employed by wolves to persist in these environments and highlight the critical importance of vegetation patches serving as refuge cover.

Assessment of Common Ragweed (Ambrosia Artemisiifolia L.) Seed Predation in Crop Fields and Their Adjacent Semi-Natural Habitats in Hungary

Ambrosia artemisiifolia has turned into a noxious weed species in agricultural fields and landscapes in Europe. Durable control options are still needed to limit the abundance of this species. Weed seed consumption by naturally occurring seed predators is a key ecosystem service in agricultural areas. Seed predation levels of common ragweed were examined in wheat and maize fields and adjacent semi-natural habitats (SNHs). To evaluate the weed seeds’ exposure to invertebrate seed predators, 20 cards each were set on the soil surface inside the crop field and in SNHs with four replications. Twenty seeds of ragweed were attached to sandpaper. Seed removal was assessed every 24 h of exposure for 5 days in June and November 2019, October 2020, and June 2021. The seed consumption level was measured according to the number of removed seeds from the seed cards. High consumption rates of ragweed seeds were found in all sampling rounds in both seasons and habitats. The seed predation rates in 2019 were stronger within crop fields in summer than in autumn with a slight difference between SNHs and inside fields. Our results demonstrate the possibility of seed predation contributing to Integrated Plant Protection (IPM) of common ragweed in rural areas.

Habitat fragmentation differentially affects invasive and native plant diversity in a human-dominated wetland island system

Managing invasive species requires identifying the factors that determine alien species invasion success. This study investigates how anthropogenic and biogeographical factors influence alien plant invasion in the Sanyang Wetlands, a human-dominated island system in Wenzhou City, China. Specifically, we analyzed whether human activities (e.g., habitat heterogeneity, proportion of road area, and cultivation) and island characteristics (e.g., island area, isolation) affect the diversity of native and invasive plant species similarly. We also assessed the applicability of the equilibrium theory of island biogeography to invasive plant species diversity and examined how these factors affect invasive plant species with different dispersal syndromes (anemochore, zoochore, and autochore). We found that both invasive and native species richness positively correlate with island area, habitat heterogeneity, and proportion of road area. However, although native species richness was negatively correlated with isolation, invasive species richness was not. The diversity and composition of invasive species with different dispersal syndromes were determined by different variables; for example, the composition and diversity of zoochores was increased by habitat heterogeneity, while anemochore species richness was increased by the proportion of road area, whereas anemochore species composition was influenced by distance to the nearest island. We conclude that habitat fragmentation differentially affects invasive and native plant diversity, aligning with the predictions of the equilibrium theory of island biogeography only for native species but not for invasive species. Our findings indicate that tailoring habitat attributes and regulating human activities could be effective strategies for mitigating the spread of invasive species in fragmented landscapes.

Determination of Some Exotic Landscape Species As Biomonitors That Can Be Used for Monitoring and Reducing Pd Pollution in the Air

Determination of Some Exotic Landscape Species As Biomonitors That Can Be Used for Monitoring and Reducing Pd Pollution in the Air

Impacts of urbanization on multiple dimensions of bird diversity in Atlantic forest landscapes

Urbanization is resulting in habitat loss and fragmentation around the world, but its effects on biodiversity remain poorly understood. We investigated how the increase of urban cover surrounding nine Brazilian Atlantic forest reserves (14 ha - 1058 ha) affects the taxonomic, functional and phylogenetic diversity of bird communities, considering forest and non-forest species separately. Using a multi-scale local landscape approach, we estimated the percentage of urban cover in circular buffers of varying radii (200–1000 m). We calculated 10 complementary metrics of bird diversity and modelled them against the percentage of urban cover using generalized additive models. Urbanization had a negative, non-linear impact on the taxonomic diversity of bird communities, with a sharp decrease of up to 50 % in the effective number of rare, typical and dominant species in landscapes with 20–40 % of urbanization. This decrease was not restricted to forest species (urban avoiders), but also affected non-forest ones (urban utilizers and dwellers). The impact of urbanization on functional and phylogenetic diversity were less evident, suggesting that the vulnerability to urbanization has a weak phylogenetic and phenotypic signal. We conclude that urbanization impacts a broad spectrum of bird clades and traits and drastically reduce the taxonomic diversity of bird communities.

A game‐theoretic systematics of conservation and management of spatial ecosystem services

AbstractSince many ecosystem services involve spatial scales beyond farm size, their preservation and management in agricultural systems depend on the interaction of the landowners. For the analysis of such interactive land use a generic dynamic land‐use model is developed that considers different payoff structures in a systematic manner and relates land‐use dynamics to these payoff structures. A landowner's own payoff depends on the land use on neighboring land parcels. The landowners’ payoffs are interpreted in a game‐theoretic manner which allows for a game‐theoretic classification of the different land‐use dynamics generated by the model. The model is analyzed to determine the proportion, spatial aggregation and temporal turnover of land‐use measures. The model results are applied to a number of cases from literature in which the management of ecosystem services involves a regional scale, including pollinator conservation, pest control, and coordination incentives for the conservation of species in fragmented landscapes. Four main domains of model behavior are identified and related to the payoff structures (type of game), characterized by the proportions and temporal turnover of land‐use measures, and by whether the system has one or two stable equilibria. An important determinant of the land‐use dynamics is the spatial heterogeneity of the landowners' payoffs which. It affects the domain and the location in the domain by which the land‐use dynamics are characterized.

Improved random forest classification model combined with C5.0 algorithm for vegetation feature analysis in non-agricultural environments

In response to the challenges posed by the high computational complexity and suboptimal classification performance of traditional random forest algorithms when dealing with high-dimensional and noisy non-agricultural vegetation satellite data, this paper proposes an enhanced random forest algorithm based on the C5.0 algorithm. The paper focuses on the Liaohe Plain, selecting two distinct non-agricultural landscape patterns in Shenbei New District and Changtu County as research objects. High-resolution satellite data from GF-2 serves as the experimental dataset. This paper introduces an ensemble feature method based on the bagging concept to improve the original random forest classification model. This method enhances the likelihood of selecting features beneficial to classifying positive class samples, avoiding excessive removal of useful features from negative samples. This approach ensures feature importance and model diversity. The C5.0 algorithm is then employed for feature selection, and the enhanced vegetation index (EVI) is utilized for vegetation coverage estimation. Results indicate that employing a multi-scale parameter selection tool, combined with limited field-measured data, facilitates the identification and classification of plant species in forest landscapes. The C5.0 algorithm effectively selects classification features, minimizing information redundancy. The established object-oriented random forest classification model achieves an impressive accuracy of 94.02% on the aerial imagery for forest classification dataset, with EVI-based vegetation coverage estimation demonstrating high accuracy. In experiments on the same test set, the proposed algorithm attains an average accuracy of 90.20%, outperforming common model algorithms such as bidirectional encoder representation from transformer, FastText, and convolutional neural network, which achieve average accuracies ranging from 84.41 to 88.33% in identifying non-agricultural artificial habitat vegetation features. The proposed algorithm exhibits a competitive edge compared to other algorithms. These research findings contribute scientific evidence for protecting agricultural ecosystems and restoring agricultural ecosystem biodiversity.

Altitudinal Variation in Species Diversity, Distribution, and Regeneration Status of a Secondary Picea Forest in Guandi Mountain, Northern China

Altitude plays a crucial role in shaping the diversity and distribution of species in forest landscapes in mountainous regions. However, existing studies often lack comprehensive analysis of the intricate relationships among environmental factors, disturbances, and species diversity. This study aims to address this gap by thoroughly analyzing major species’ diversity, distribution, and regeneration status, along with their influencing factors, across different altitudinal gradients (1850 to 2350 m). Field surveys were conducted to examine the major species in different vegetation layers of the secondary Picea forest in Guandi Mountain. The key findings from the study include the following: (1) the study area recorded a total of nine species of adult trees, belonging to eight genera in five families, fourteen species of shrubs from eight genera in five families, and fifty-two herb species representing forty-eight genera in twenty-six families. Dominant species varied across layers, with Picea asperata Mast. and Larix principis-rupprechtii Mayr. dominating the arborous layer, Lonicera ferdinandii Franch. and Cotoneaster acutifolius Turcz. in the shrub layer, and Poa pratensis L. and Duchesnea indica (Andrews.) Focke in the herb layer. (2) Altitude significantly influenced species diversity, with the most pronounced effects observed in the shrub and herb layers. (3) Tree species regeneration varied with altitude, with Picea asperata exhibiting the highest regeneration performance, particularly in the high-altitude zone (2250–2350 m). Regeneration parameters were significantly correlated with species diversity indices in both tree and shrub layers. (4) Redundancy analysis revealed that, apart from altitude, cutting (p = 0.015) influenced the species diversity of the tree layer, while annual precipitation (p = 0.006) and temperature (p = 0.01) determined the diversity of the shrub layer. Grazing (p = 0.042) was identified as a determining factor for species diversity in the herb layer. Overall, these findings provide valuable insights into the sustainable management of forest ecosystems in the study area and offer practical guidance for forest management in similar mountainous landscapes worldwide.

Use of agricultural fields by Natterjack toads: Implications for pesticide exposure

Land sharing conservation strategies might not work if wildlife is exposed to plant protection products. Plant protection products are used to protect crops against harmful organisms yet they can also have unwanted side effects on non-target organisms. Amphibians are one group of non-target organisms for which there is evidence that plant protection products can have negative effects on individuals and populations. Despite much research on amphibian ecotoxicology, not much is known about the exposure of amphibians to plant protection products in agricultural landscapes. Here, we study habitat use and movement behaviour of an endangered amphibian, the Natterjack toad Epidalea calamita, in two study areas in Switzerland. We placed arrays of artificial cover boards in agricultural fields and adjacent non-agricultural habitats and used a photographic mark-recapture approach to track individual toads, both adults and juveniles, during and after the reproductive season in the terrestrial habitat. We used multistate and spatial mark-recapture models to analyse the data. Toads used the agricultural fields during spring and summer and set up their home ranges within the fields but there was a great turnover of individuals. Toad densities were higher in agricultural fields than other habitat types, including a nature reserve suitable for the species. Toads preferred open soils and avoided grassy meadows typical of agricultural set-asides, suggesting that the conservation of the species in agricultural landscapes requires new types of biodiversity promotion areas. The results of the study show that toads use agricultural fields during most of the growing season and are thus likely to be exposed to plant protection products.

Comparing local ecological knowledge with camera trap data to study mammal occurrence in anthropogenic landscapes of the Garden Route Biosphere Reserve

AbstractAccurate information on wildlife occurrence in anthropogenic landscapes is essential to develop effective conservation measures. Monitoring multiple mammal species in heterogeneous landscapes can be challenging because of the diversity of land‐uses and species behaviors. Therefore, different monitoring methods are better adapted to different contexts. We compared data obtained from camera traps with data gathered through an online survey to document the presence of mammal species in mosaic landscapes of the Garden Route Biosphere Reserve in South Africa. The survey detected the same 15 species as the camera traps as well as the additional common duiker. Both methods effectively detected most large mammal species, whereas results were less consistent for smaller species and carnivores. Combining the two methods enabled us to produce more robust estimates of species absence and confirm species presence reported by survey respondents. In less disturbed areas, respondents with good ecological knowledge were effective at monitoring mammal species, while extending the spatial coverage of the study. Bearing in mind the limitations of each method, camera traps and an online survey could complement each other if combined. Together, they can provide a more comprehensive understanding of mammal communities in anthropogenic landscapes, increasing both spatial coverage and the number of species sightings.

Energetics‐based connectivity mapping reveals new conservation opportunities for the endangered tiger in Nepal

AbstractEnhancing habitat connectivity is a key strategy for conserving endangered species in anthropogenic landscapes. However, connectivity planning often overlooks the crucial energetic costs to animals of traversing complex terrains. We applied a novel approach for estimating energy costs of movement for tigers – a globally endangered species. We used those estimates to calculate landscape connectivity for these animals across the extreme altitudinal gradient of Nepal, where recent sightings of tigers at higher elevations (~3200 m) suggest an upward range expansion from the tiger‐rich lowlands. To evaluate our estimates, we simulated tiger routes to higher‐elevation locations and compared modeled energy costs of those ascents to those derived from a previous model calibrated with data from GPS‐collared tigers in Russia. In areas below 3200 m, we found about 7.5 times greater land areas with high connectivity outside protected areas (~51 000 km2) than inside (~6800 km2). However, most of the highly connected areas below 3200 m consist of croplands (56%). Importantly, community‐managed forests, which spanned the altitudinal gradient, tended to include areas with moderate levels of connectivity. Our estimates of energy costs and those from Russia showed a strong consensus (ρ = 0.70, P < 0.05), with ours better capturing the higher energy costs of traversing mountains and of very large total ascents. Our results show that while barriers to tiger movement across Nepal are ubiquitous, other effective area‐based conservation measures (OECMs), like community‐managed forests, can play prominent roles in promoting tiger habitat connectivity while minimizing human–tiger conflict across anthropogenic landscapes. Our results also underscore the utility of integrating first principles of energy efficiency into connectivity analyses and planning.

Unravelling the dynamics: Large mammal occupancy modelling in a West African tropical forest

AbstractThis study investigates the response of large mammal populations to human‐induced modifications in the Omo‐Shasha‐Oluwa Forest Reserves landscape. The impact of habitat alterations on species diversity and distribution remains poorly understood in this region. Over four seasons from May 2017 to April 2019, 52 sites were surveyed, revealing the presence of 12 large mammal species across six families. Maxwell's duiker exhibited the highest overall occupancy (0.897 ± 0.062), while the Forest elephant had the lowest (0.115 ± 0.043). Forest buffalo experienced the greatest increase in site occupancy (0.290 ± 0.076 to 0.358 ± 0.098), whereas the Mona monkey saw the most significant decrease (0.713 to 0.651). The study employed single‐species, multi‐season occupancy modelling, predicting colonisation and extinction events solely for the civet (ϒ = 0.347 ± 0.154; ε = 0.041 ± 0.031) and Red river hog (ϒ = 0.158 ± 0.098; ε = 0.098 ± 0.059). The likelihood of Civet cat and Red river hog colonisation increased with distance from the nearest settlement. These findings enhance our understanding of habitat characteristics influencing large mammal distribution, offering valuable insights for the conservation of these species in forest landscapes.

Lasting effects of avian‐frugivore interactions on seed dispersal and seedling establishment

Abstract The consequences of plant–animal interactions often transcend the mere encounter stage, as those encounters are followed by a chain of subsequent stages on the plant's reproductive cycle that ultimately determine fitness. Yet, the dissemination and recruitment stages of animal‐mediated seed dispersal are seldom analysed jointly, hindering a full understanding of the ecology of seed dispersal. We analyse the dispersal and recruitment of a fleshy‐fruited plant (Pistacia lentiscus), from fruit production to seedling survival up to their second year. We link early reproductive investment of individual plants to seedling recruitment and explore the role played by seed viability, the coterie of frugivores and microhabitat seed deposition. The proportion of viable seeds was generally low (mean = 34%) but highly variable among individual plants (range: 0%–95%). Seed viability did not seem to have a direct effect on individual plant's recruitment. We recorded 28 bird species feeding on P. lentiscus fruits or seeds. Their contribution to plant recruitment was mainly determined by their intensity of fruit consumption and probability to disperse viable seeds. Most frugivores presented non‐random microhabitat preferences, delivering uneven seed contributions to different sites. Post‐dispersal seed predation by rodents was the most limiting phase in P. lentiscus recruitment. Yet, microhabitats showing the lowest predation rates received the lowest seed rain. Hence, we found a decoupling of the dissemination and recruitment stages: most seeds do not arrive at the most suitable microhabitats. We estimate P. lentiscus plants need to produce c. 5 × 105 fruits to recruit a single seedling that survives to its second summer in our study site. Its success as a prevalent species in Mediterranean lowland landscapes relies on its high fecundity and thorough fruit removal and dispersal by a diversified frugivore assemblage, which compensates for the high seed unviability characteristic of this genus. Synthesis: Measuring the delayed, post‐dispersal outcomes of animal frugivory interactions may overturn inferences based on consumption observations only. Seed rain patterns are often decoupled from microhabitats' suitability for seedling recruitment. Hence, more integrative studies that encompass the entire plant reproductive cycle (from fruit production to seedling recruitment) are needed to fully understand frugivores' lasting contribution to plant regeneration in natural populations.

Plant species diversity in cocoa and rubber tree landscapes in Côte d’Ivoire

In Côte d’Ivoire, although slash and burn practice, particularly associated with cocoa and rubber farming, have greatly contributed to the degradation of forest cover and biodiversity loss. There is a dearth of studies documenting the latter. A study was conducted in the central-west and southern regions respectively with the objective to bridge this gap by assessing the diversity of trees species in cocoa and rubber landscapes. An inventory of tree species in eighteen cocoa and rubber plantations was conducted respectively in 45 plots of 400 m² each. Also, 15 plots of the same area were delimited in forests considered as reference systems. Cocoa plantations are 8 times richer than rubber plantations. Moreover, tree density varied from 36 to 56.8 stems.ha-1 in cocoa plantations including 6 species with special-status for conservation and from 0 to 5 stems.ha-1 in rubber plantations. This study confirmed that rubber farming is a driver of tree diversity loss thereby revealing the need to work out credible rubber agroforestry options. As for cocoa farming, the high diversity of companion trees is indicative of the high potential of transitioning to cocoa agroforestry. The contribution of this study to agroecological transition based on cocoa and rubber agroforestry in Côte d’Ivoire is discussed.

Identifying opportunities and constraints to effective management of invasive Australian wattle (Acacia) species in grassland landscapes, South Africa

Identifying opportunities and constraints to effective management of invasive Australian wattle (Acacia) species in grassland landscapes, South Africa

Mechanisms of trunk cavity formation of large old trees in urban landscapes: A case study on four tree species in Beijing

Cavity trees play a crucial role in enhancing urban biodiversity, despite limited habitat space. Understanding these aspects is of paramount importance for promoting biodiversity in urban environments. Nevertheless, there is a paucity of extensive research on the characteristics and formation mechanisms of cavity trees across diverse tree species in urban landscapes. In this study, Arbotom sonic tree tomography was used to identify cavity cores within four representative large old tree species in Beijing, encompassing two broadleaved species [Styphnolobium japonicum (L.) Schott, n = 301; and Ginkgo biloba L., n = 100] and two conifer species [Platycladus orientalis (L.) Franco, n = 515; and Pinus tabuliformis Carr., n = 404]. We introduce a cavity index to quantify tree decay and explore cavity characteristics and formation mechanisms across different tree species. Our results reveal that the cavity index is primarily linked to diameter at breast height (DBH), tree age, and trunk health in the four large old tree species studied. The formation of cavities in trees is primarily attributed to external disturbances that lead to tree damage. Subsequent fungal infections occur when a tree's defense mechanisms fail to prevent them, resulting in trunk decay and the formation of cavities. It is worth noting that different tree species exhibit varying defense mechanisms, with coniferous species generally displaying stronger defenses than broad-leaved species. In summary, the formation of cavity trees in urban landscapes is influenced by a combination of internal and external factors, with the tree species' defense mechanisms and the extent of external disturbances determining cavity characteristics. The findings indicate a higher likelihood of cavities in the outer parts of large old trees in southern regions compared with those in northern regions. Coniferous species also exhibited fewer cavities than broad-leaved species. Further, urban trees are more susceptible to external damage that can lead to cavity development, thereby necessitating attention to their growth environment and morphological conditions. However, understanding these factors can aid managers in crafting conservation policies that enhance urban biodiversity and provide habitats for urban wildlife, thereby maximizing the societal benefits.