Shrub Density Research Articles

African elephants influence browse availability for black rhinoceroses in Gonarezhou National Park, Zimbabwe

AbstractTranslocations are essential for the establishment of new populations of the critically endangered black rhinoceros (Diceros bicornis), but success will largely depend on forage availability. We investigated the degree of competition for woody browse between African savanna elephants (Loxodonta africana) and a recently reintroduced population of rhinoceroses in Gonarezhou National Park in Zimbabwe in the dry season of 2022. We examined overlap in space use and selection for plant species, stem diameters, and feeding height by measuring use of shrubs by both species at 75 sites across a range of topo‐edaphic conditions. Areas heavily used by rhinoceroses had high shrub densities, were close to water, and were on alkaline soils with elevated conductivity. Sites with medium to high levels of rhinoceros use were nested within areas of high elephant use. We also observed high elephant use in areas not favored by rhinoceroses, occurring farther from water and having lower shrub densities. Both species avoided thickets on acidic soils. There was substantial overlap in feeding areas, the plant species selected, and foraging height, although elephants used stems with larger diameters than rhinoceroses. Feeding by elephants on woody plants often resulted in a proliferation of small‐diameter coppice stems, which rhinoceroses used more than non‐coppice growth. Elephants did not appear to favor small coppice stems, indicating a degree of elephant‐induced facilitation of browse for rhinoceroses. Evidence for competition with elephants indicates black rhinoceroses may be best introduced into areas with a low elephant density.

Distribution Patterns and Habitat Preferences of Five Globally Threatened and Endemic Montane Orthoptera (Parnassiana and Oropodisma)

Greece is a European hotspot for Orthoptera (378 species), yet it has been scarcely explored. We investigated the distribution and habitat preferences of the species of two endemic Orthoptera genera, Parnassiana and Oropodisma, in the montane ecosystems of central Greece. We conducted field surveys from 2021 to 2024 in 174 sites across seven mountains. The species of both genera preferred habitats above 1500 m, with species-specific preferences for microhabitat parameters: Parnassiana species favored moderate slopes with dense shrub cover, while Oropodisma species favored substrates with intermediate stone cover and relatively high vegetation cover. Species distribution models estimated the area of suitable habitat for Parnassiana to be at 5 km2 and Oropodisma at 3.28 km2. The Normalized Difference Vegetation Index (NDVI) and potential evapotranspiration were the key environmental drivers of the habitat suitability for both genera. Generalized regression models showed that altitude positively influenced Parnassiana population density, peaking at 2200 m, whereas rock and soil cover negatively impacted Oropodisma population densities. The results emphasize the critical role of montane habitats in sustaining these species and provide essential data for future research and conservation strategies.

Shrub height estimation for habitat conservation in NW Iberian Peninsula (Spain) using UAV LiDAR point clouds

ABSTRACT This study aimed to develop and validate a method of estimating 3D parameters from DJI Zenmuse L1 LiDAR on DJI Matrice 300 RTK UAV data to characterise and monitor the structure and conservation status of dense shrub formations. The shrub heights were estimated using Progressive Morphological Filter (PMF) and the Ground Filter module of the FUSION/LDV software. A digital terrain model (DTM) was interpolated with RMSE 0.23 and 0.27 m, respectively, and a normalised canopy height model (nCHM) was calculated by subtracting it from the LiDAR data and the best DTM obtained. The reliability of the estimates was evaluated against georeferenced field data. In addition, the study examined the impact of vegetation characteristics and return reduction in the original point cloud on the accuracy of LiDAR-data derived . Significant differences were found in the correlations between observed and estimated data for the DTM (R2 = 0.9998) and nCHM heights (R2 = 0.51/0.54). The corresponding RMSE values were 0.23 and 0.34 m. Moreover, no significant differences in the reliability were found for different vegetation types, whereas reduction point cloud density (up to 25–50 returns/m2) did not significantly affect accuracy. In conclusion, lightweight UAV LiDAR can effectively detect sub-metric scale vegetation 3D structure, useful for fine-scale habitat conservation.

Joint Influence of Forest Strata Attributes and Abiotic Factors on Herbaceous Plant Abundance in South Korean Forest Restoration Sites: Native Versus Alien Species

The success of ecosystem restoration is often evaluated by the stable establishment and growth of native plants while preventing the spread of alien plants. However, research on the factors and mechanisms controlling the abundance (richness and coverage) of native and alien plants remains limited. To address this, we analyzed data from 167 plots (100 m2) in forest restoration sites in South Korea. We assessed the effects of abiotic factors (topography, climate, and soil), biotic factors, and the number of years integrally since restoration on both plant groups by using a piecewise structural equation model. Native plant abundance was influenced by shrub density (species richness: β = 0.19; coverage: β = 0.20) and available phosphorus (β = 0.19), while alien plant abundance was controlled by soil pH (species richness: β = 0.45), elevation (β = −0.15), species richness, and tree (β = −0.15) and shrub species richness (β = −0.16). The number of years since restoration has indirectly affected native and alien plants through shrub species richness and shrub coverage. Our results indicate that high resource availability, such as light, in the early stages of restoration may allow native and alien herbaceous plants to coexist. However, as vegetation and forest strata develop, reduced light availability can lead to a decline in alien species and the dominance of native plants. We also provide management strategies to suppress alien plants by promoting structural complexity within forest stands.

A multiscale analysis of factors influencing Setophaga striata (Blackpoll Warbler) occupancy and abundance during the nonbreeding season in eastern Colombia

ABSTRACT Setophaga striata (Blackpoll Warbler), one of the few boreal-breeding migratory birds that migrates to the Orinoco and Amazon regions, is experiencing steep population declines. However, knowledge of the species’ distribution and habitat use during the nonbreeding season is limited. Here, we explore how stationary nonbreeding season (December to April) occupancy probabilities vary across regional and landscape scales, and with vegetation structure for S. striata in eastern Colombia. By running single-species, single-season hierarchical occupancy models and N-mixture models, we evaluated how regional (annual precipitation, nonbreeding season precipitation, driest month, elevation, and net primary productivity), landscape (habitat type and % forest in the landscape), and vegetation structure variables influenced occupancy by S. striata. In the regional analysis, occupancy was positively influenced by stationary nonbreeding precipitation and net primary productivity, and was predicted to peak at elevations between 500 and 1,000 m. At the landscape scale, occupancy and abundance were higher in agroforestry systems (in order of magnitude: shade-grown cacao, citrus plantations and silvopastures) than in forested habitats. In relation to vegetation structure, occupancy was negatively correlated with a principal component containing shrub density, canopy height, and canopy cover. Within the Orinoco region, a spatial prediction based on our results supported high occupancy rates in moister areas along and close to the Andean foothills and where the Orinoco grasslands transition into Amazonian forests. Our results highlight the importance of landscapes containing agroforestry systems as stationary nonbreeding habitats for S. striata in Colombia’s Orinoco region and the importance of promoting agroforestry systems, like shade-grown cacao, in areas with higher nonbreeding season precipitation and net primary productivity values in order to increase habitat availability for the species.

Spatial dynamics and drivers of recent changes in grass and shrub cover in submontane grassland plant communities

Shrub encroachment into grassland ecosystems has been increasingly observed and documented worldwide in recent years. A grass–shrub transition can affect the diversity, abundance and functional integrity of grassland plant communities and understanding the drivers behind these processes is therefore crucial. While potential environmental drivers are often investigated, the role of spatial patterns of neighbouring shrub density in local shrub encroachment has been less well studied. The aim of this study is to investigate the relative role of neighbouring shrub density and topography as potential key drivers of shrub encroachment in a typical montane grassland ecosystem in New Zealand. We used the SPOT (Satellite Pour l’Observation) 6/7 multispectral imagery captured on one day in 2013 and in 2017 to calculate recent changes in shrub/grass cover during this period. Using the Normalised Difference Vegetation Index (NDVI), we classified the study area into grassland and shrubland and quantified the extent and change in these two land-cover types over the study period. We then investigated the relationships between changes in land cover and neighbourhood shrub density, elevation and aspect. Between 2013 and 2017, there was an overall shrubland increase of + 0.35% of the study area per year, and grassland decrease of −0.43% per year. Locations at which any change in vegetation type occurred were more likely to be at mid-elevation (c. 600–1,000 m a.s.l.) and on west-facing slopes. Highest shrub expansion rates were observed on areas that were on warmer, north-facing slopes and at elevations below 900 m a.s.l.; this is consistent with areas below the pre-human, natural treeline which is estimated to be at very similar elevations. We found a marked threshold in the degree to which neighbourhood shrub density correlated with local shrub encroachment: local shrub encroachment only occurred when shrub cover in the neighbourhood exceeded 40% and peaked at c. 60% indicating the potential for a sudden grass–shrub regime shift once shrub cover reaches a certain level. Our study provides new evidence from the Southern Hemisphere of a measurable and interacting effect of topography and neighbourhood shrub density on recent shrub encroachment rates in montane grasslands even over short time periods.

Spatial distribution of shrubs and perennial plants under grazing disturbance in the desert steppe of Inner Mongolia

The desert steppe is unique as a transition zone from the steppe to the desert of the Eurasian Steppe. The spatial distribution of shrubs and perennial plants has changed due to long-term disturbance caused by overgrazing in the ecosystem. This study aimed to determine the degree of patchiness of shrubs and perennial plants under grazing disturbance, which is of great significance to better understand the succession mechanism of plant community in the desert steppe. This study investigated the spatial distribution of shrubs and perennial plants under four stocking rates (no grazing, CK, 0 sheep·hm−2·half year−1; light grazing, LG, 0.93 sheep·hm−2·half year−1; moderate grazing, MG, 1.82 sheep·hm−2·half year−1; heavy grazing, HG, 2.71 sheep·hm−2·half year−1) in the desert steppe of Inner Mongolia, primarily using geostatistical methods. The density of perennial grasses increased with increasing stocking rate, while its height decreased (except for HG). The density and height of the shrubs and the perennial forbs showed an exponential or gradual decline. The spatial distribution of shrubs and perennial plants is mainly affected by structural factors such as topography, soil parent material, and climate, and the density of shrubs and perennial plants is most sensitive to changes in stocking rate. An appropriate stocking rate increases the spatial heterogeneity of shrubs and perennial plants, but heavy grazing reduces the spatial heterogeneity of shrubs and perennial plants.

Continuous Monitoring of Vegetation and Soil Recovery After Eucalyptus grandis Removal in Dense Trees and Shrubs Areas

ABSTRACTInvasion by invasive alien plants is a global challenge and South Africa has invested billions of Rands to manage invaders through the Working for Water programme. However, regular monitoring after alien plant clearing is hardly done, yet it forms the basis for assessing clearing programme effectiveness, particularly ecosystem recovery trajectories. I monitored both vegetation and soil recovery 6 years after Eucalyptus grandis clearing by Working for Water at Zvakanaka Farm in Limpopo Province of South Africa. Vegetation diversity and soil physical properties were surveyed in 2019 and re‐surveyed in 2022 on fell‐and‐removal and fell‐and‐stackburn cleared treatments and compared to the nearby uninvaded treatment. Results show a significant increase in species richness in 2022 compared to 2019 in the fell‐and‐removal treatment. Cover of both native trees and shrubs as well as forbs was significantly higher in 2022 compared to 2019 in the fell‐and‐removal treatment compared to the fell‐and‐stackburn treatment. Most secondary invaders such as Acacia mearnsii, E. cloeziana, Lantana camara and Rubus rigidus that frequently occurred in 2019 showed decreased occurrence in 2022 on both cleared treatments. Between the two sampling years, soil compaction improved on the fell‐and‐removal treatment only, whereas hydraulic conductivity increased significantly in 2022 compared to 2019 in both the fell‐and‐removal and fell‐and‐stackburn treatments. Soils that were strongly and severely repellent in 2019 in the fell‐and‐stackburn treatment were becoming slightly repellent in 2022. These results show varied vegetation and soil improvements between 2019 and 2022 in both the fell‐and‐removal and fell‐and‐stackburn cleared treatments an indication that recovery is moving towards a positive vegetation and soil recovery trajectory in the direction of the uninvaded treatment. Recommendations for successful passive restoration such as secondary invasion follow‐up clearing are discussed.

Thinning relationships of woody encroachers in a US southwestern shrubland

Woody plant encroachment degrades the economic and environmental potential of drylands by altering processes such as nutrient fluxes, ecohydrology, and ecosystem services. Though past research has investigated the encroachment process, relatively little is known about post-encroachment shrub community ecology. To better quantify dynamics within post-woody encroachment shrub communities, we combined USGS lidar height data and multispectral imagery to estimate shrub density, shrub height, shrub cover, and shrub volume across the Jornada Basin Long Term Ecological Research (JRN-LTER) site in southern New Mexico, USA. Structural estimates were analyzed in search of telltale signs of community competition, specifically, the presence of thinning relationships. Results demonstrated density-dependent thinning relationships in shrub communities of creosote and mesquite, indicating a large role for competition in arid shrub communities even at relatively low shrub densities and cover (∼35% cover). In addition, shrub volume estimates better modeled the expected thinning dynamics of shrub communities than shrub canopy cover measurements. Overall, our results indicate the utility of lidar data in extending two-dimensional descriptions of woody vegetation structure (i.e., woody canopy cover) into the critical third dimension (i.e., woody plant volume), as well as the relative importance of competition and demographic bottlenecks to vegetation structure in drylands.

Dependence of the population state of the midday gerbil (<i>meriones meridianus</i>, rodentia, gerbillidae) on the provision of forage resources in different seasons of the year in the north-western caspian

In the conditions of the North-Western Caspian Sea, the state of the midday sand lance population is determined by the dynamics of food resources. An important component of the environment that determines the condition of the midday gerbil is bush thickets, which serve as a good shelter for animals. It has been established that on a sand dune, where a higher density of shrubs is noted, compared to open areas of the deserted steppe, the productivity of vegetation increases and the species composition of plants changes. The relationship between gerbil population density and vegetation productivity was shown (R = 0.74, P 0.05). In addition, the relationship between the number of gerbils and the productivity of bluegrass bulbs (Poa bulbosa) is shown, which fluctuated during the years of research in the sand dune area from 3.7 to 5.5 c/ha of dry weight, and in the desert steppe area from 2.3 to 3.8 c/ha. In accordance with the nature of the provision of food resources, changes in the number of midday gerbils were noted in different seasons of the year from 4 to 24 individuals/ha on sand dunes and from 2 to 14 individuals/ha in the desert steppe.

Livestock Detection and Counting in Kenyan Rangelands Using Aerial Imagery and Deep Learning Techniques

Accurate livestock counts are essential for effective pastureland management. High spatial resolution remote sensing, coupled with deep learning, has shown promising results in livestock detection. However, challenges persist, particularly when the targets are small and in a heterogeneous environment, such as those in African rangelands. This study evaluated nine state-of-the-art object detection models, four variants each from YOLOv5 and YOLOv8, and Faster R-CNN, for detecting cattle in 10 cm resolution aerial RGB imagery in Kenya. The experiment involved 1039 images with 9641 labels for training from sites with varying land cover characteristics. The trained models were evaluated on 277 images and 2642 labels in the test dataset, and their performance was compared using Precision, Recall, and Average Precision (AP0.5–0.95). The results indicated that reduced spatial resolution, dense shrub cover, and shadows diminish the model’s ability to distinguish cattle from the background. The YOLOv8m architecture achieved the best AP0.5–0.95 accuracy of 39.6% with Precision and Recall of 91.0% and 83.4%, respectively. Despite its superior performance, YOLOv8m had the highest counting error of −8%. By contrast, YOLOv5m with AP0.5–0.95 of 39.3% attained the most accurate cattle count with RMSE of 1.3 and R2 of 0.98 for variable cattle herd densities. These results highlight that a model with high AP0.5–0.95 detection accuracy may struggle with counting cattle accurately. Nevertheless, these findings suggest the potential to upscale aerial-imagery-trained object detection models to satellite imagery for conducting cattle censuses over large areas. In addition, accurate cattle counts will support sustainable pastureland management by ensuring stock numbers do not exceed the forage available for grazing, thereby mitigating overgrazing.

Study on the contributions of 2D and 3D urban morphologies to the thermal environment under local climate zones

With the changes in global climate and rapid urbanization, identifying the contribution of urban morphology to the thermal environment under different scenarios could be helpful in proposing differentiated optimization responses of different scenarios for improving the thermal environment by means of natural cooling. This study calculated 2D and 3D metrics and retrieved surface temperature based on building vector data, land use, electronic map, the remote sensing images. Then, the study of spatial scale sensitivity was developed to build a nested multi-scale Local Climate Zone (LCZ) (NMSLCZ) map. Finally, the eXtreme Gradient Boost (XGBoost) regression model was performed to explore the relative contributions of 2D and 3D morphologies of different LCZ scenarios to surface temperatures. The results of scale sensitivity analysis showed the size of the optimal spatial scale decreased with the increase in building height. The 3D morphologies show more significant effects on LST variations than 2D morphologies. The surface temperature mainly by built type is significantly higher than that mainly by land cover type. Scenarios representing dense trees, shrubs, low vegetation, and water have significant cooling effects. In the scenarios of built types, the surface temperature of compact and large low-rise buildings is higher than that of the other building forms. Our findings provide a new perspective for LCZ mapping of scale optimization of the thermal environment. Meanwhile, the contributions of 2D and 3D morphologies on LSTs could help urban planners and managers understand the impacts of climate change and propose relevant strategies toward sustainable cities.

Integrating key ecosystem services to study the spatio-temporal dynamics and determinants of ecosystem health in Wuhan’s central urban area

The central areas of many Chinese cities have experienced large-scale urbanization in recent decades, a trend that is affecting the quality of life of residents and posing challenges to the sustainable development of urban ecosystems. Hence, it is vital to conduct assessments of urban ecosystems’ health conditions to ensure their sustainability. In this study, the spatial and temporal dynamics of ecosystem health in the central city of Wuhan were analyzed using the Vigor-Organization-Resilience-Service (VORS) model. The sensitivity of ecosystem health at different scales was also investigated using hierarchical health assessment delineation and random forest regression methods. The results showed that the composite index of ecosystem health has been declining since 2000, highlighting the negative impacts of shrinking ecological space, declining service capacity and urban expansion. Health zoning divides areas into five categories. Meanwhile, the health zones are located in areas of dense shrubs, cropland and water bodies on the edge of the central city, while the weak zones are mainly in the core of the city, which is 99.33 % impervious surface. The main factors influencing ecosystem health, including impervious surface area, water bodies and topography, vary from region to region. The study proposes targeted ecological management strategies for different health zones in Wuhan, emphasizing ecosystem protection and providing guidance for sustainable urban development.

Changes in plant diversity of European lowland forests: Increased homogenization and expansion of shade-tolerant trees

European lowland forests have undergone significant transformations over the past century due to increased canopy closure, eutrophication and plant invasions. The new millennium has brought plant invasions, alien fungal pathogens, and extreme weather conditions, all contributing to forest diebacks. However, the response of plant diversity remains poorly understood. We examined changes in understorey vegetation following a decade (2012–2021) of severe drought in four temperate lowland forest types (dominated by oaks, hornbeams, ashes, and willows) to understand how water availability, canopy openness, and alien fungal pathogens altered diversity in interaction with climate change. Following an exceptionally warm decade, the vegetation exhibited increased homogeneity, with denser shrub and herb layers, likely resulting from diminished tree canopy, particularly in hornbeam and ash forests. Homogenization was manifested by the colonization of plants with conservative life-history strategies (higher leaf dry matter content) to cope with increased drought. Consequently, communities with fewer species increased their species richness, while species-rich communities experienced impoverishment. Conversely, herbaceous species with higher specific leaf area were declining. Compositional changes were particularly prominent in hornbeam and oakwoods at the drier end of moisture gradient where the understorey became dominated by woody plants. Ashwoods were opening up due to ash dieback by fungal pathogens, causing replacement of wetland forbs by nitrophilous forbs and woody saplings. The overall number of species decreased in oakwoods but increased in hornbeam and ashwoods due to increased cover of grasses and shade-tolerant woody species, mostly Acer campestre. Conversely, willow understorey vegetation at the wetter end of the moisture gradient remained relatively stable. Our findings suggest shifts towards more homogeneous vegetation. Conservation plans for managing the remnants of species-rich lowland forests should consider the accelerated environmental changes linked to canopy alterations, biological invasions, and extreme climate events.

Suppression of reed canarygrass by assisted succession: A sixteen‐year restoration experiment

Abstract Assisted succession could enable long‐term restoration where successional trajectories stall due to competition from invasive plants. Many invasives are shade‐intolerant; therefore, interventions reducing light availability should suppress invasion and re‐establish successional processes. However, given how ubiquitous nonlinearities are in ecology, restoration success also depends on identifying critical system thresholds, for example invader abundances below which regeneration of desired species is possible. We report the successful use of assisted succession to restore a swamp forest invaded by Phalaris arundinacea (reed canarygrass; hereafter Phalaris), initiated by a high‐density planting of woody species to outcompete Phalaris by reducing light availability. We established five pre‐planting treatments in a Phalaris near‐monoculture in Wisconsin, USA: herbicide‐only, herbicide+plough, herbicide+burn, mow+herbicide and control. In 2003 we planted 22 tree and shrub species at high densities, then in 2019 we censused the site to: (1) screen for long‐term differences among treatments, (2) evaluate long‐term effects of our interventions on community composition and (3) characterize the critical thresholds that enable invader suppression and restoration success. Vegetation responses and light availability across our four pre‐planting invader removal treatments did not differ. Late fall glyphosate application suppressed Phalaris long enough that a dense canopy of native woody species could establish and eventually out‐shade it. Overstory tree and shrub densities of 0.071/m2 suppressed Phalaris to 50% cover, but, due to nonlinearities, much higher densities were needed to reduce light availability and thus Phalaris cover enough to shift the system from being invader‐dominated. Compositional similarities between juvenile woody species and the overstory suggest a long‐term restoration success. Synthesis and applications. Invasive species management and the restoration of target plant communities can be aided by assisting successional trajectories that have stalled. We document a restoration strategy for forests invaded by shade‐intolerant invaders that is both effective and economical, as only a simple site preparation and single planting effort is required. Establishing a dense canopy of woody species in this way can break the feedbacks maintaining invader dominance and re‐introduce feedbacks enabling long‐term ecosystem recovery. We also illustrate the value of identifying critical thresholds influencing the abundance and impact of key invasive species.

Native shrub densities predict burrow co-occurrence patterns in Central California Drylands

Ecological resource availability is crucial for the persistence and survival of local desert animal communities. Dryland resources such as shrubs and burrows positively benefit animal species by mitigating harsh abiotic factors and providing habitat. Understanding the role of native shrubs, many of which serve as foundation species within desert regions, as well as the function of underground burrows as resources, provides insights into habitat utilization. In this study, we seek to better understand the co-occurrence of these two resources as a first step in quantifying key patterns locally and regionally in drylands. We tested whether the presence of burrows increased with the density of foundational shrubs near the burrows at two scales—within a 5 m radius of every burrow recorded and at the site level—defined as discrete ecological areas. We performed fieldwork across 31 sites within the arid and semiarid regions of Central California. We used a combination of burrow field surveys and satellite imagery to document both vertebrate animal burrow frequencies and shrub densities. Additionally, the accuracy of the shrub data was verified through ground truthing. Both fine-scale and site-level shrub densities positively predicted the relative likelihood of burrows and the frequency of burrows, respectively. The existence of two highly utilized dryland resources and the relationship between them signal that areas abundant in both resources will likely better support resident animal species. This finding underscores the significance of incorporating both shrub density and burrow frequency in studies of habitat interconnectivity and quality. The co-occurrence patterns of these resources will support novel habitat management and conservation strategies designed around both conservation and restoration efforts.

Summer habitat selection by Mrs Hume’s Pheasant (Syrmaticus humiae) on Jinzhong Mountain, northwest Guangxi, China: implications for determining effective conservation actions using radio transmitters

Abstract In the present study, summer habitat preference of Mrs Hume’s Pheasant (Syrmaticus humiae) was studied in Jinzhong Mountain Nature Reserve, Guangxi Province. Eight birds were equipped with radio transmitters and habitat characteristics of experiment and control quadrat sites, respectively, were measured. Our results indicated that: 200 m to 400 m distance to habitat edge, less than 200 m distance to water, over 400 m distance to human habitation, over 601 m distance to the road, over 60% tree cover, less than 40% shrub cover, less than 20% herb cover, over 60% leaf litter cover, height of tree over 10.1 m, tree density over 20 individuals per quadrat, shrub height over 2.1 m, shrub density less than 10 individuals per quadrat, height of herb species over 0.5 m, herb density less than 10 Individuals per quadrat, diameter of tree over 30 cm, and abundant food were the habitat characteristics. The elevation, herb density, and height of tree and shrub exhibited no significant differences (), but other factors showed significant differences between quadrat sites and control quadrat plot (). Results of a principal components analysis (PCA) demonstrated that the first five components accounted for 64.282% of the total variance. Food availability in different habitat patches is the vital factor affecting habitat selection by Mrs Hume’s Pheasant; the other factors showed no significant effects on habitat selection by Mrs Hume’s Pheasant in the subtropical forest. This suggests that habitat selection behavior of Mrs Hume’s Pheasant is in fact a trade-off between obtaining food and prey escape, which is an adaptive behavior and a life strategy of this near-threatened bird species.

Rodent communities in a neglected grassland landscape: Investigating species-specific responses of grassland rodents to habitat type and shrub presence

Arid grasslands worldwide are transitioning to scrublands due to shrub encroachment, resulting in habitats with varying shrub cover. Shrubs play a crucial role in grassland ecosystems, offering trade-offs to rodents in terms of visibility, shelter, and food availability, thereby affecting their occurrence and distribution. This study explores the link between habitat characteristics and rodent activity and density, focusing on shrub presence. In the Tirunelveli district of southern India, we measured rodent density and activity across three grassland types with increasing shrub presence. Our findings reveal species-specific responses to shrub density. The Soft-furred rat (Millardia meltada) dominated, showing adaptability to different shrub levels, while the black rat (Rattus Rattus) was least represented. Fine-scale analysis indicates a positive association between shrub presence and rodent captures. Grassland obligate species like the Indian gerbil (Tatera indica) exhibited reduced activity in densely shrubbed sites, whereas semi-arboreal species like the Indian palm squirrel (Funumbulus palmarum) showed increased activity. This study underscores the importance of considering habitat structure in grassland ecosystem management for the conservation of rodent diversity and ecosystem health.

Habitat changes explain shifts in bird community composition in abandoned military training areas: Lessons for conservation

Military training areas are important biodiversity refuges and may serve as viable components of regional conservation networks, mainly due to the blocking of ecological succession by the disturbance regime creating a heterogeneous open habitat mosaic hosting many threatened species. However, European armies have undergone downsizing over the past decades and numerous military training areas have been abandoned. The assessment of the consequences of this abandonment for biodiversity would show us whether these abandoned areas still provide conservation benefits. For this purpose, we carried out bird surveys in 30 abandoned military training areas in Czechia. The surveys were performed in two periods (2009 and 2020–2021) to track small-scale changes in land cover and bird abundance after the areas were abandoned in the 1990s. We tested (i) whether changes in bird abundance were related to land cover changes and (ii) whether the observed bird species’ responses to the land cover changes can be explained by species-specific characteristics. Multivariate spatial analyses uncovered significant shifts in land cover composition towards a higher representation of dense shrub, forest and built-up areas at the expense of open areas represented by grassland and sparse shrub. These land cover changes explained a small but significant part of bird abundance variation across the areas. Correspondingly, species benefiting from these land cover changes were associated with dense scrub or forest, such as the Common Chiffchaff, Willow Warbler, or Eurasian Blackcap, whereas species suffering from these changes were associated with grassland, such as the European Stonechat and Eurasian Skylark. Phylogenetically informed interspecific analysis aiming to explain changes in bird abundance between periods confirmed that population declines were linked to open habitat preference, while population increases were linked to the preference for dense shrub and forest. In addition, we found that protected species increased their abundance, most likely due to the existence of conservation management that kept their habitats available. These patterns indicate that military training areas transform toward later successional stages after their abandonment with corresponding changes in bird community composition. However, these changes may not necessarily be negative provided that species of conservation concern enjoy the support of conservation management.

Tall, large-diameter trees and dense shrub layer as key determinants of the abundance and composition of bird communities in oak-dominated forests

Increasing human activity is altering the structure of forests, which affects the composition of communities, including birds. However, little is known about the key forest structure variables that determine the richness of bird communities in European temperate oak forests. We, therefore, aimed to identify key variables in these habitats that could contribute to the design of management strategies for forest conservation by surveying 11 oak-dominated forest sites throughout the mid-mountain range of Hungary at 86 survey points to reveal the role of different compositional and structural variables for forest stands that influence the breeding bird assemblages in the forests at the functional group and individual species levels. Based on decision tree modelling, our results showed that the density of trees larger than 30 cm DBH was an overall important variable, indicating that large-diameter trees were essential to provide diverse bird communities. The total abundance of birds, the foliage-gleaners, primary and secondary cavity nesters, residents, and five specific bird species were related to the density of high trunk diameter trees. The abundance of shrub nesters was negatively influenced by a high density of trees over 10 cm DBH. The density of the shrub layer positively affected total bird abundance and the abundance of foliage gleaners, secondary cavity nesters and residents. Analysis of the co-dominant tree species showed that the presence of linden, beech, and hornbeam was important in influencing the abundance of various bird species, e.g., Eurasian Treecreeper (Certhia familiaris), Marsh Tit (Poecile palustris) and Wood Warbler (Phylloscopus sibilatrix). Our results indicated that large trees, high tree diversity, and dense shrub layer were essential for forest bird communities and are critical targets for protection to maintain diverse and abundant bird communities in oak-dominated forest habitats.