Abundance Of Shrubs Research Articles

Propagating observation errors to enable scalable and rigorous enumeration of plant population abundance with aerial imagery

Abstract Estimating and monitoring plant population size is fundamental for ecological research, as well as conservation and restoration programs. High‐resolution imagery has potential to facilitate such estimation and monitoring. However, remotely sensed estimates typically have higher uncertainty than field measurements, risking biased inference on population status. We present a model that accounts for false negative (missed plants) and false positive (misclassified or double‐counted plants) error in counts from high‐resolution imagery via integration with ground data. We apply it to estimate the abundance of a foundational shrub species in post‐wildfire landscapes in the western United States. In these landscapes, plant recruitment is crucial for ecological recovery but locally patchy, motivating the use of spatially extensive measurements from unoccupied aerial systems (UAS). Integrating >16 ha of UAS imagery with >700 georeferenced field plots, we fit our model to generate insights into the prevalence and drivers of observation errors associated with classification algorithms used to distinguish individual plants, relationships between abundance and landscape context, and to generate spatially explicit maps of shrub abundance. Raw counts of plant abundance in high‐resolution imagery resulted in substantial false negative and false positive observation errors. The probability of detecting (p) adult plants (0.25 m tall) varied between sites within 0.52 < < 0.82, whereas the detection of smaller plants (<0.25 m) was lower, 0.03 < < 0.3. On average, we estimate that 19% of all detected plants were false positive errors, which varied spatially in relation to topographic predictors. Abundance declined toward the interior of previous wildfires and was positively associated with terrain roughness. Our study demonstrates that integrated models accounting for imperfect detection improve estimates of plant population abundance derived from inherently imperfect UAS imagery. We believe such models will further improve inference on plant population dynamics—relevant to restoration, wildlife habitat and related objectives—and echo previous calls for remote sensing applications to better differentiate between ecological and observational processes.

Sacred sites provide urban green spaces that maintain bird diversity in the megacity of Tokyo, Japan

Green spaces in cities are thought to play an important role in maintaining urban biodiversity. However, it is difficult to create large new areas of green space in big cities. Therefore, existing green spaces need to be conserved and properly managed to conserve urban biodiversity. In big Japanese cities, sacred sites such as shrines, temples, and historic parks are some of the common types of green space. In addition to their role as religious spaces, they may also play an important role in urban biodiversity conservation because of their function as long-term reserves of natural vegetation. In this study, we examined the function of shrines, temples, and historic parks in Bunkyo ward, Tokyo, in maintaining bird diversity by comparing them with urban parks. In addition, a vegetation survey was conducted to identify environmental factors that affect bird diversity, and differences in the bird species observed in each type of green space are discussed. The heterogeneity of bird species composition between study sites was higher among shrines and temples than among urban parks.Forest bird abundance was higher during the breeding season and bird species richness was higher in winter at shrines and temples and historic parks than in urban parks. Bird diversity was positively affected by the abundance of shrubs and evergreen trees. We found that sacred sites were more important than urban parks for maintaining bird diversity. The results also suggested that differences in vegetation structure are a cause of this pattern, and small green spaces in the grounds of sacred sites are managed in a way that is more suitable for maintaining bird diversity.However, shrines and temples, despite their strong historical and cultural value, are threatened by recent urbanization. It is necessary to maintain and properly manage these green spaces as part of urban ecosystems.

Applying palaeoecological analogues to contemporary challenges: community-level effects of canopy gaps caused by systematic decline of a prevalent tree species

Temperate woodland vegetation is initially determined by spatiotemporal and historical factors, mediated by complex biotic interactions. However, catastrophic events such as disease outbreaks (e.g., sweet chestnut blight, ash dieback), infestations of insect pests, and human-accelerated climate change can create canopy gaps due to systematic decline in, or loss of, tree species that was once an important part of the canopy. Resultant cascade effects have the potential to alter the composition of woodland ecosystems quickly and radically, but inherent lag times make primary research into these effects challenging. Here, we explore change in woodland vegetation at 10 sites in response to canopy opening using the Elm Decline, a rapid loss of Ulmus in woodlands across northwestern Europe ~ 5800 years ago that coexisted alongside other stressors such as increasing human activity, as a palaeoecological analogue. For arboreal taxa, community evenness significantly decreased, within-site turnover significantly increased, and richness remained unchanged. Changes in arboreal taxa were highly site-specific but there was a substantial decline in woody climbing taxa, especially Hedera (ivy), across the majority of sites. For shrub taxa, richness significantly increased but evenness and turnover remained consistent. Interestingly, however, there was a significant increase in abundance of shrubs at 70% of sites, including Calluna (heather), Ilex (holly) and Corylus (hazel), suggesting structural change. Surprisingly, there was no change in richness, evenness or turnover for herb taxa, possibly because change was highly variable spatially. However, there was a marked uptick in the disturbance indicator Plantago (plantain). Overall, these findings suggest that woodlands with sustained reduction in, or loss of, a tree species that once formed an important part of the canopy has profound, but often spatially idiosyncratic, impacts on vegetation diversity (richness), composition (evenness), stability (turnover), and on abundance of specific taxa, especially within the shrub layer. Use of this palaeoecological analogue, which was itself complicated by cooccurring changes in human activity, provides a valuable empirical insight into possible cascade effects of similar change in canopy opening in contemporary settings, including Ash Dieback.

A case study on the impact of coppicing on small mammal diversity: First evidence from the high Agri Valley in the Basilicata Region, Italy

Forestry seems to have a significant impact on the diversity and composition of forest small mammal communities. Coppicing is one of the most widely adopted silvicultural systems in Europe and its effect on the entire small mammals community remains unclear. Thus, our study aimed to preliminary assess the stand-level effect of different coppice woodland elements on community richness, focusing on forest small mammal species. Furthermore, a second aim was to assess the effect of these woodland stand elements on different small mammal taxonomic groups to evaluate possible differential responses within the community. We identified three different coppice age classes, and selected a total of 15 coppice-with-standards forest stands. Additionally, we collected data about understory shrub structure and composition. Fur samples were collected using the hair tube sampling method. We found a significant effect of the coppice age on the number of species detected in communities. Furthermore, we found a differential response between glirid and murid families, with glirid being positively affected by a higher shrub abundance, which is instead severely reduced by coppicing.

The Response of Rhizosphere Microbial C and N-Cycling Gene Abundance of Sand-Fixing Shrub to Stand Age Following Desert Restoration.

Rhizosphere microorganisms play a pivotal role in biogeochemical cycles, particularly in relation to carbon (C) and nitrogen (N) cycles. However, the impact of stand age on the composition of rhizosphere microbial communities and the abundance involved in C and N cycling remains largely unexplored in restoration ecosystems dominated by shrubs of temperate deserts. This study focuses on revealing changes in microbial composition and functional genes in the rhizosphere soil of Caragana korshinskii after revegetation, as well as their response mechanisms to changes in environmental factors. The alpha diversity of bacteria tended to increase with stand age, whereas that of fungi decreased. The abundance of denitrification; dissimilatory nitrate reduction to ammonium, nitrification, and ammonium assimilation; and C fixation-related gene levels increased with stand age, whereas those related to the degradation of starch, pectin, hemicellulose, cellulose, and aromatics decreased. The parameters MBC, MBN, and TC were the key factors affecting the bacterial community, whereas the fungal community was regulated by TN, EC, pH, and MBC. Stand age indirectly regulated C and N cycling functions of genes through altered soil properties and microbial community structures. This study presents a novel approach to accurately evaluate the C and N cycling dynamics within ecosystems at various stages of restoration.

Structure of Ground Vegetation and Natural Regeneration of Tree Species in 12- to 15-Year-Old Bilberry Pine Forest-Clear-cut Complex of Middle Taiga Subzone.

Logging in mature stands where part of the forest is harvested in one or several cuts and part is retained (clearcutting and alternate strip cutting) results in the formation of an ecotone complex (EC), which includes a forest (F) zone, a forest edge (FE) as a transition from the forest to the clear-cut under the canopy, a clear-cut edge (CE) as a transition from the forest to the clear-cut outside of the canopy, and the clear-cut proper (C). The composition and structure of ground vegetation and natural regeneration of woody species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula sp., Populus tremula L., Sorbus aucuparia L., and Juniperus communis L.) were studied in a bilberry pine forest-clear-cut ecotone complex 12-15 years after stand removal. Specific structural features of ground vegetation and undergrowth (including tree regeneration) were observed in each of the four zones of the ecotone complex formed after logging of the mature forest. Atypical forest habitat (zone F) showed a minimum number of young regeneration of Pinus sylvestris, Picea abies, Betula sp., Populus tremula, and Sorbus aucuparia and the highest abundance of the lingonberry V. vitis-idaea L. and bilberry Vaccinium myrtillus L. with a maximum height and a maximum yield of bilberry plants. The amount of tree regeneration in the FE zone was much the same as in the F zone. The projective cover, maximum shoot height, and yield of bilberry and the maximum shoot height of lingonberry in the FE zone were significantly lower than in the F zone. The transitional zone on the clear-cut side (CE) and the clear-cut proper (C) strikingly differed from the forest (F and FE) zones of the ecotone complex by a greater number of deciduous and pine regeneration and a low abundance of dwarf shrubs. The clear-cut proper (C) differed from the CE zone by a higher abundance of grasses and forbs and an established tree regeneration layer composed of pine, birch, and aspen.

Centering Amah Mutsun voices in the analysis of a culturally important, fire-managed coastal grassland.

Indigenous communities throughout California, USA, are increasingly advocating for and practicing cultural fire stewardship, leading to a host of social, cultural, and ecological benefits. Simultaneously, state agencies are recognizing the importance of controlled burning and cultural fire as a means of reducing the risk of severe wildfire while benefiting fire-adapted ecosystems. However, much of the current research on the impacts of controlled burning ignores the cultural importance of these ecosystems, and risks further marginalizing Indigenous knowledge systems. Our work adds a critical Indigenous perspective to the study of controlled burning in California's unique coastal grasslands, one of the most biodiverse and endangered ecosystems in the country. In this study, we partnered with the Amah Mutsun Tribal Band to investigate how the abundance and occurrence of shrubs, cultural plants, and invasive plants differed among three adjacent coastal grasslands with varying fire histories. These three sites are emblematic of the state's diverging approaches to grassland management: fire suppression, fire suppression followed by wildfire, and an exceedingly rare example of a grassland that has been repeatedly burned approximately every 2 years for more than 30 years. We found that Danthonia californica was significantly more abundant on the burned sites, whereas all included shrub species (Baccharis pilularis, Frangula californica, and Rubus ursinus) were significantly more abundant on the site with no recorded fire, results that have important implications for future cultural revitalization efforts and the loss of coastal grasslands to shrub encroachment. In addition to conducting a culturally relevant vegetation survey, we used Sentinel-2 satellite imagery to compare the relative severities of the two most recent fire events within the study area. Critically, we used interviews with Amah Mutsun tribal members to contextualize the results of our vegetation survey and remote sensing analysis, and to investigate how cultural burning contrasts from typical Western fire management approaches in this region. Our study is a novel example of how interviews, field data, and satellite imagery can be combined to gain a deeper ecological and cultural understanding of fire in California's endangered coastal grasslands.

Soil nutrient availability affects tundra plant community composition and plant–vole interactions

ABSTRACT Climate change in the Arctic is predicted to drastically alter carbon and nutrient pools, plant communities, and plant–animal interactions. We examined how four levels of long-term (16 years) nutrient addition in moist acidic tundra affected plant community structure and the abundance of Eriophorum vaginatum, the preferred forage for tundra voles (Microtus oeconomus). We also explored how simulated press and pulse herbivory for four years affected Eriophorum at these different nutrient levels. Shifts in plant community structure, reductions in species diversity and richness, and decreased Eriophorum abundance were pronounced at the highest levels of nutrient addition. Eriophorum abundance was negatively correlated with deciduous shrub abundance, likely caused by light limitation in fertilized plots. Added nutrients generally increased Eriophorum leaf length, but effects varied among years and simulated herbivory treatments. After being clipped once, Eriophorum leaves regrew in fertilized plots to the same length as leaves that had not been clipped, demonstrating recovery. Our results show how interannual variation in plant growth and animal activity might exacerbate or dampen responses over multiple years. Changes to plant community composition and plant–vole interactions associated with increased soil nutrients resulting from warming could have cascading impacts on arctic ecosystems and carbon cycling.

Low weed and cool‐season grass abundances likely necessary for warm‐season grass, forb, and shrub establishment

Plants seeded in degraded grasslands often fail to establish. In the Northern Great Plains, perennial cool‐season grasses are easiest to establish, and they sometimes competitively suppress warm‐season grasses, shrubs, and forbs. Seeding cool‐season grasses at low rates sometimes benefits other seeded plants but risks greater weed abundances. To identify grass seed rates low enough to allow other plants to establish but high enough to constrain weeds, we varied cool‐season grass seed rates while holding warm‐season grass, shrub, and forb seed rates fixed. The first couple growing seasons after seeding, we hypothesized cover of other seeded plants and weeds would decrease with increasing cool‐season grass seed rate. During later growing seasons, we hypothesized weed cover would become independent of grass seed rates due to seeded plants increasing in plots seeded at low rates. Neither hypothesis was supported. Because weed abundances were high, warm‐season grasses, shrubs, and forbs apparently experienced similarly intense competition regardless of grass rate, so low rates did not increase seeded plant establishment. Regardless of seed rate, cool‐season grass cover did not increase between the second and final (i.e. fourth) growing season, perhaps because of low precipitation. Increasing warm‐season grass, shrub, and forb abundances will require controlling weeds in addition to lowering cool‐season grass seed rates. Even these steps will not always increase establishment because native plants sometimes died before controlling weeds with herbicides became feasible and grass competition became important. Lowering grass rates without implementing weed control risks sites becoming weedy for prolonged periods.

Structural heterogeneity predicts ecological resistance and resilience to wildfire in arid shrublands

ContextDynamic feedbacks between physical structure and ecological function drive ecosystem productivity, resilience, and biodiversity maintenance. Detailed maps of canopy structure enable comprehensive evaluations of structure–function relationships. However, these relationships are scale-dependent, and identifying relevant spatial scales to link structure to function remains challenging.ObjectivesWe identified optimal scales to relate structure heterogeneity to ecological resistance, measured as the impacts of wildfire on canopy structure, and ecological resilience, measured as native shrub recruitment. We further investigated whether structural heterogeneity can aid spatial predictions of shrub recruitment.MethodsUsing high-resolution imagery from unoccupied aerial systems (UAS), we mapped structural heterogeneity across ten semi-arid landscapes, undergoing a disturbance-mediated regime shift from native shrubland to dominance by invasive annual grasses. We then applied wavelet analysis to decompose structural heterogeneity into discrete scales and related these scales to ecological metrics of resilience and resistance.ResultsWe found strong indicators of scale dependence in the tested relationships. Wildfire effects were most prominent at a single scale of structural heterogeneity (2.34 m), while the abundance of shrub recruits was sensitive to structural heterogeneity at a range of scales, from 0.07 – 2.34 m. Structural heterogeneity enabled out-of-site predictions of shrub recruitment (R2 = 0.55). The best-performing predictive model included structural heterogeneity metrics across multiple scales.ConclusionsOur results demonstrate that identifying structure–function relationships requires analyses that explicitly account for spatial scale. As high-resolution imagery enables spatially extensive maps of canopy heterogeneity, models for scale dependence will aid our understanding of resilience mechanisms in imperiled arid ecosystems.

Ecosystem‐wide responses to fire and large mammal herbivores in an African savanna

AbstractFire and large mammal herbivores (LMH) are the principal top‐down forces maintaining savanna structure. Nonetheless, experiments designed to investigate interactions between fire and LMH are rare in savannas, and relationships between environmental variation and biodiversity in the context of fire and LMH are poorly understood. This study addresses these gaps by manipulating the presence of LMH and early and late dry season fires in a tropical African savanna. In addition, this work simultaneously explores environmental variables including soil and foliar quality, vegetation cover, and nearby water sources to more holistically describe factors affecting savanna functioning and biodiversity. After 1 year of experimental treatments, changes in vegetation were already apparent. Shrub abundance and richness and grass richness were higher in the absence of LMH, while grass biomass increased three‐fold in burned plots as compared to unburned plots. Foliar nutrients tended to increase in open plots, while phenolics decreased. Amphibian abundance decreased with early burns and was higher with LMH. In contrast, small mammal abundance and richness increased without LMH and with time since fire. Richness and foraging of LMH were highest after late burns. These results demonstrate ecosystem‐wide effects of LMH, illustrating the importance of considering multiple taxa when designing fire management programs. For example, burning negatively affected amphibians and small mammals and changed vegetation at the same time it increased LMH foraging. In the long‐term, this experiment will shed light on interacting effects of fire and LMH on savanna biodiversity and function.Abstract in Portuguese is available with the online material.

Shrub effects on the decomposition microenvironment and changes in litter quality have opposing effects on litter decomposition

Increasing abundance of tall deciduous shrubs has been shown to affect tundra soil properties, which may further affect carbon and nitrogen cycling in these soils, including through effects on litter decomposition. These tall deciduous shrubs produce a higher quantity of litter, and also a different quality of litter, than tundra species in non-shrub dominated tundra, both of which may affect community-wide decomposition rates. We examined how presence of tall deciduous shrubs, including resulting increases in litter quantity, affects litter decomposition through effects on both the decomposition environment and on litter composition. In a factorial experiment, we modified the decomposition environment by manipulating both the abundance of tall deciduous shrubs (present/absent) and their litter (absent, natural, and doubled). In each environment we decomposed litter of the tall deciduous shrub, Betula glandulosa and two other dominant species in our study area; Salix reticulata, a dwarf deciduous shrub, and Carex consimilis, a graminoid. We report that while tall Betula shrub presence reduced decomposition rates, decomposition was not affected by manipulations of litter quantity. Although litter decomposed slower under deciduous shrubs, B. glandulosa litter decomposed faster than the litter of the other dominant tundra plant species. However, the reduction in decomposition rates due to tall deciduous shrub presence and higher decomposition rates of B. glandulosa litter in comparison to other plant species were of the same magnitude and these opposing effects may result in little to no change of shrub encroachment on litter decomposition rate overall.

Litter accumulation suppresses grass production but facilitates shrub expansion in a long‐term fenced grassland

AbstractShrub expansion is increasing in grasslands worldwide and has profound effects on biodiversity and ecosystem functions. Shrub expansion has primarily been explained by extrinsic factors such as climate change and human activities, yet the roles of intrinsic shrub demographic population dynamic and shrub–grass interaction remain poorly understood. With a paired mown and exclosure comparison experiment and baseline levels of shrub abundance in a semiarid grassland, we confirmed that long‐term livestock exclusion promotes expansion of two native shrubs, Artemisia sacrorum and Caragana brachypoda. Shrub abundance increased during the livestock exclusion period. Shrub biomass in fenced plots was about 5‐ to 10‐fold greater than in mown plots. Both increase in population density and individual size (especially height) contributed to shrub increase. The mechanism behind this was the divergent effects of litter accumulation on shrubs and grasses. Litter accumulation suppressed grass production, while facilitating shrub recruitment and growth. Our findings highlight the potential role of litter accumulation‐mediated shifts in shrub–grass interactions, which should be incorporated into grazing top‐down control to better predict the restoration outcomes of grassland management changes. The identified internal biotic mechanism raises the possibility that removal of accumulated litter by grazing or mowing may be an alternative way to maintain or restore a grass‐dominated state in shrub expansion areas.

Changes in taxonomic and functional composition of subalpine plant communities in response to climate change under contrasting conditions of bedrock and snow cover duration

AbstractQuestionsWe assessed interactions between climate change, bedrock types and snow cover duration on the trajectories of taxonomic and functional composition of subalpine plant communities. We predict (i) an increase in species richness on siliceous bedrock due to a reduced competition and a decrease in richness on calcareous bedrock due to increasing drought stress; (ii) decreasing snow cover duration should induce a higher shrub encroachment in hollows as compared to ridges; and (iii) increasing growing season temperature should induce taller sizes and more conservative growth traits, in particular in hollows.LocationSubalpine belt of the Grandes Rousses mountain range, southwestern Alps (France).Methods189 vegetation plots were sampled in 1997 and 2017–2018. The duration of snow cover was assessed during two years in 1995–1997 and five functional traits were measured on 108 species in 2021. We performed multivariate analyses, quantified community‐weighted means (CWM) of traits and used ANOVAs to detect responses to local‐scale factors and changes in snow cover, temperature and precipitation since 1997 according to a nearby meteorological station.ResultsOverall, taxonomic composition weakly changed and changes were more dependent on the position of communities along the snow cover duration gradient than on their bedrock type. The abundance of drought‐tolerant species increased at the border of hollows and there was, over all communities, a slight increase in the abundance of dwarf shrubs and tall herbaceous species, a strong decrease in short herbaceous species and, thus, an overall decrease in species richness. There were important overall changes in CWM of size traits, in particular leaf area which increased the most in hollows irrespective of bedrock types.ConclusionIn this subalpine site the effects of decreasing snow cover duration overwhelmed the effects of bedrocks, which may explain the overall increase in competitive species and decrease in species richness.

Impact of Digital Marketing on Transformation of Patanjali Ayurvedic Products

India is a land of ancient rich cultural of ayurvedic medicines. There are abundance of herbs and shrubs which only founding India and have miraculous impacts some of major diseases and a great help to mankind. Patanjali Ayurvedic is one of the giant Ayurvedic product making in India, which has expanded its business in very less span of time. With the advancement in technology the marketing techniques of the firms has also been totally changed and from the traditional marketing techniques now a day almost all the companies have stepped into the world of digital marketing, Patanjali Ayurvedic ltd. Has also increased its presence on digital world and has tried hard to improve their marketing strategies to get new customers around the globe. This study tries to evaluate the impact of digital marketing on Patanjali products through conducting a survey in Delhi NCR and Uttar Pradesh with sample size of 65 people. Keywords: Patanjali, Digital Marketing, Ayurvedic, E-Commerce.

The interplay between historical land‐use and the distribution of Helichrysum shrubs in an African‐protected grassland

AbstractHuman land use can have lasting impacts on landscape characteristic, yet there remains a lack of information on how former land use affects plant communities in protected African grasslands. In this study, we investigated how land uses prior to the creation of Kitulo National Park, Tanzania, shaped the presence and abundance of the native shrub, Helichrysum species. We evaluated both plant species composition and soil properties across the park by dividing our sample into three different zones of historical land use based on participatory mapping. We divided the park into three former land uses: (1) livestock grazed and cultivated; (2) grazed only and (3) wild grazing with limited human impact. We observed that former grazed cultivated land use had five times higher Helichrysum abundance than former ‘wild’ land use. Soil pH, magnesium and phosphorus levels varied significantly across zones of historical land use but not between sites with and without Helichrysum species. Helichrysum splendidum was more abundant in soils with low soil phosphorus and magnesium concentrations. Our study demonstrates that historic grazing and cropping land uses through changes in soil nutrient properties can explain current Helichrysum species spread in protected areas. As such, conservation management plans would benefit from integrating mapping of former land uses to target interventions for problematic encroaching shrubs.

Wildfire-induced increases in photosynthesis in boreal forest ecosystems of North America.

Observations of the annual cycle of atmospheric CO2 in high northern latitudes provide evidence for an increase in terrestrial metabolism in Arctic tundra and boreal forest ecosystems. However, the mechanisms driving these changes are not yet fully understood. One proposed hypothesis is that ecological change from disturbance, such as wildfire, could increase the magnitude and change the phase of net ecosystem exchange through shifts in plant community composition. Yet, little quantitative work has evaluated this potential mechanism at a regional scale. Here we investigate how fire disturbance influences landscape-level patterns of photosynthesis across western boreal North America. We use Alaska and Canadian large fire databases to identify the perimeters of wildfires, a Landsat-derived land cover time series to characterize plant functional types (PFTs), and solar-induced fluorescence (SIF) from the Orbiting Carbon Observatory-2 (OCO-2) as a proxy for photosynthesis. We analyze these datasets to characterize post-fire changes in plant succession and photosynthetic activity using a space-for-time approach. We find that increases in herbaceous and sparse vegetation, shrub, and deciduous broadleaf forest PFTs during mid-succession yield enhancements in SIF by 8-40% during June and July for 2- to 59-year stands relative to pre-fire controls. From the analysis of post-fire land cover changes within individual ecoregions and modeling, we identify two mechanisms by which fires contribute to long-term trends in SIF. First, increases in annual burning are shifting the stand age distribution, leading to increases in the abundance of shrubs and deciduous broadleaf forests that have considerably higher SIF during early- and mid-summer. Second, fire appears to facilitate a long-term shift from evergreen conifer to broadleaf deciduous forest in the Boreal Plain ecoregion. These findings suggest that increasing fire can contribute substantially to positive trends in seasonal CO2 exchange without a close coupling to long-term increases in carbon storage.

An empirical study on the response of university students to viewing autumn secondary forest phytocommunities landscape via virtual reality in Northeast China

Secondary forests play a critical role in the natural environment and have the potential to provide significant benefits for human physical and mental well-being. The secondary forests in the Sanhu National Nature Reserve, located in Northeast China, have extremely high ecological value. In this study, we selected seven types of secondary forest phytocommunities in this region, measured ecological indicators at various sites, and captured panoramic photos on-site. Virtual reality (VR) technology was used to present and record participants' electroencephalogram (EEG) data for studying neural activity. Statistical analyses were conducted using SPSS 26.0 to evaluate the data obtained from the study. The results showed that participants preferred landscapes predominantly consisting of mixed forests of Pinus koraiensis mixed broad-leaved forest (FP1.α and FP2.α: p = 0.001), featuring colorful and verdant scenery. Experiencing these seven types of secondary forest landscapes through virtual reality improved participants' mood and had a positive impact on them. Within a certain range (300–400 m, 0-30°), participants favored landscapes with higher elevations (FP1.β: p = 0.008, FP2.β: p = 0.001, F3.β: p = 0.006) and gentler slopes (F3.θ: p = 0.002, F4.θ: p = 0.031, F8.θ: p = 0.005). Additionally, participants showed a preference for secondary forest landscapes with a moderate canopy density ranging from 0.7 to 0.8 (FP1.θ: p = 0.015, FP2.θ: p = 0.014). The study also found that participants preferred landscapes with a greater abundance of trees and shrubs, as well as taller and narrower trees. Moreover, our study revealed that males favored autumn forest landscapes more than females, with graduate students showing a stronger preference compared to undergraduates. Urban residents also displayed a stronger preference for these landscapes over rural residents, and individuals from the Southern region expressed a higher inclination than their Northern counterparts (T3.δ: p = 0.002, p = 0.001 for others). These findings can provide reference for the design and plant arrangement of urban forest landscapes.

Landscape features, garden management, and microhabitats influence prey removal and predator composition in urban agroecosystems

Agroecosystem management at microhabitat, habitat, and landscape scales shapes natural enemy communities, with critical implications for ecosystem services. Yet few studies examine the impacts of small to large scale habitat management features on predator communities, abundance of predator species, or removal of prey items from urban agroecosystems. In this study, we used observations and a sentinel prey removal experiment to examine the impact of substrate (prey placed on the ground vs. on kale plants), microhabitat (prey placed under vegetation, on bare soil in open areas, or on mulch in open areas), local garden management features, and landscape features on predator species composition and removal of two prey species in urban gardens in the California central coast. We found that both microhabitat characteristics and substrate type shaped prey removal rates within urban gardens, and microhabitat, but not substrate, impacted predator species composition. In addition, both garden management (floral abundance, herbaceous plant richness, and tree and shrub abundance) and landscape features (urban land cover within 2 km) influenced prey removal and predator composition. Nearly all prey removal of eggs was accomplished by ants; larvae predators were more diverse and included ants, birds, lizards, wasps, and spiders. Although predator composition was mediated by many habitat features, prey removal was greater under vegetation, from the ground, when floral abundance in gardens was high, and in gardens with fewer trees and shrubs. Considering how these different management features affect predator foraging behavior and interactions will be a promising next step in this field.

Biomass allocation and plant morphology explain the difference in shrub species abundance in a temperate forest.

In forested ecosystems, shrubs must succeed in persisting in low-light environments, while simultaneously having the ability to rapidly expand and occupy newly created canopy openings, yet little is known about the traits that make this possible. We hypothesize that shrub species that are abundant in the understory exhibit a specific set of functional traits that define their ability to persist during unfavorable periods and to rapidly exploit newly created habitats. We tested this by comparing field-measured functional traits such as biomass allocation, leaf display, crown morphology, and leaf traits, across individual size classes and two gap-forest environments of five shrub species. We observed significant differences in traits between species, size classes, and gap-forest environments. These differences were primarily related to biomass allocation traits, followed by leaf display, crown morphology, and leaf traits. Abundant shrubs like mountain maple (Acer spicatum) and hazelnut (Corylus cornuta) invested significantly more biomass in roots, had a larger total leaf area, and displayed leaves in a more efficient manner to intercept light. The high investment in root biomass can be interpreted as shrubs exploiting the persistence and colonization strategy through resprouting. Permanent sub-canopy status likely explains the importance of efficient leaf display, wherein abundant shrubs had a large leaf area with minimal support structures.