Search Results (462)

As spatial scale changes, the ecological processes and mechanisms that determine community patterns change. To understand these spatial effects, we established a medium-sized forest plot in an evergreen and deciduous broad-leaved mixed forest in Guilin, Guangxi, southwestern China. Here, we compared the fit of niche and neutral models to the observed species abundance distributions (SADs) at three sampling scales (10 m × 10 m, 20 m × 20 m, 50 m × 50 m). We also performed a PER-SIMPER analysis to further evaluate the relative contribution of niche and neutral processes based on taxon occurrence data. Our results showed that niche-based selection and dispersal-based neutral processes are simultaneously expressed at the 10 m × 10 m and 20 m × 20 m sampling scales. Additionally, dispersal-based neutral processes were predominant at each sampling scale. From these results, we found that the dispersal-based neutral process is the prominent driver for forest community structure in a typical karst forest environment. Ultimately, our work will be useful for future restoration and reconstruction efforts in karst forest communities, showing that environmental heterogeneity, inter-species relationships, and geographic spatial differences should be considered in these efforts. Full article

Globally, increasing temperatures due to climate change have severely affected natural ecosystems in several regions of the world; however, the impact on the alpine plant may be particularly profound, further raising the risk of extinction for rare and endangered alpine plants. To identify how alpine species have responded to past climate change and to predict the potential geographic distribution of species under future climate change, we investigated the distribution records of A. chensiensis, an endangered alpine plant in the Qinling Mountains listed in the Red List. In this study, the optimized MaxEnt model was used to analyse the key environmental variables related to the distribution of A. chensiensis based on 93 wild distribution records and six environmental variables. The potential distribution areas of A. chensiensis in the last interglacial (LIG), the last glacial maximum (LGM), the current period, and the 2050s and 2070s were simulated. Our results showed that temperature is critical to the distribution of A. chensiensis, with the mean temperature of the coldest quarter being the most important climatic factor affecting the distribution of this species. In addition, ecological niche modeling analysis showed that the A. chensiensis distribution area in the last interglacial experiencing population expansion and, during the last glacial maximum occurring, a population contraction. Under the emission scenarios in the 2050s and 2070s, the suitable distribution area would contract significantly, and the migration routes of the centroids tended to migrate toward the southern high-altitude mountains, suggesting a strong response from the A. chensiensis distribution to climate change. Collectively, the results of this study provide a comprehensive and multidimensional perspective on the geographic distribution pattern and history of population dynamics for the endemic, rare, and endangered species, A. chensiensis, and it underscores the significant impact of geological and climatic changes on the geographic pattern of alpine species populations. Full article

To evaluate the ecological niche of China’s photovoltaic agriculture, this paper firstly analyzed the composition of photovoltaic agriculture and constructed the ecosystem of photovoltaic agriculture. Then, we defined the concept of the ecological niche of photovoltaic agriculture, and based on this the preliminary niche evaluation index system was constructed. Further, redundant indicators in the preliminary index system were deleted based on the rough set theory, and the final niche evaluation index system was constructed. Finally, the ecological niche of photovoltaic agriculture was evaluated using the DANP method and cloud model. We found that the niche level of China’s photovoltaic agriculture is between low and medium levels. Specifically, the level of resource niche is the highest, between medium and high levels; following is policy niche, near medium level; then is environmental niche, which is at a slightly lower medium level; the last three in turn are technology niche, social niche and economic niche. The technology should fully realize the synergistic effect of photovoltaic power generation and agricultural production, and the policy should play better environmental, social and economic functions on this basis to achieve a higher niche level of China’s photovoltaic agriculture. Full article

The historic western edge of the bison (Bison bison) range and the ecological processes that caused its formation are frequently debated with important implications for bison restoration across North America. We test the hypothesis that a combination of bottom-up habitat suitability and top-down harvest pressure from Indigenous peoples were important processes in forming the western edge of bison distribution. Using 9384 historical journal observations from 1691–1928, we employ MaxEnt ecological niche modelling to identify suitable bison habitat across the Western Cordillera from bottom-up climatic, land cover, and topographic factors. We then use mixed-effect logistic regression to test if bison occurrence in journal records can be in part explained by the abundance of humans, wolves, or grizzly bears, in addition to MaxEnt-derived habitat suitability. We find support for our hypothesis because of the limited suitable habitat in the Rocky Mountains that likely prevented westward bison dispersal from their core habitat, and there was a negative relationship between bison occurrence and human harvest pressure. On this basis, we propose that intensive human harvest from large populations in the Western Cordillera, subsidized by other wildlife, salmon, and vegetation resources, is an underappreciated socioecological process that needs to be restored alongside bison populations. Co-managing bison with Indigenous peoples will also mitigate the adverse effects of overabundant bison populations and maximize the ecological and cultural benefits of bison restoration. Full article

Emerging or alternative crops are those that have been recently introduced in response to new demands and commercial opportunities. The fig has been introduced as an alternative fruit crop in Mexico due to its high nutritional, nutraceutical, and antioxidant capacity. A total of 644 points of presence were downloaded and filtered according to climatic ranges and agricultural areas, leaving 68 records. The MaxEnt algorithm was used to develop the habitat suitability models for current and future climate. The bioclimatic variables of the global circulation models, Hadley Centre Global Environment Model version 2-EarthSystem (HADGEM2-ES) and Max Planck Institute for Meteorology-Earth System Model Low Resolution (MPI-ESM-LR), were used under scenarios 2.6 and 8.5. The changes in the fig area for Mexico were analyzed based on the generated models. Under the current climate, 359,575.76 km² were estimated for 2050, and a loss of area for the excellent category was estimated for both models and scenarios; however, for the MPI-ESM-LR model projected to 2070, an increase of 5.51% and 0.39% was estimated for scenarios 2.6 and 8.5, respectively. The effect of climate change on agronomic species such as figs will be expressed in variations in climatic ranges and areas suitable for their development. The results of this study reveal the negative and positive effects of climate change on fig habitat suitability in Mexico. The dynamics of changes in surface area will be reflected mainly in northern and central Mexico. Full article

Provincial economic development in the VUCA era (V: volatility; U: uncertainty; C: complexity; A: ambiguity) is facing great challenges. Comprehensively measuring the provincial ecological niche and giving enhancement strategies are significant for the implementation of the Yellow River Strategy. By constructing the S–R–F (Status–Relationship–Function) provincial ecological niche measurement framework using the SEM model (the structural equation modeling), this paper calculated the provincial ecological niche of the Yellow River Basin from 2005 to 2019 using an ecological niche width model, an ecological niche overlap model and an ecological niche suitability model and gave improvement strategies through spatial positioning. Results: (1) The ecological niche breadth in the Yellow River Basin is uneven, showing a spatial pattern of “low in the upper reaches, high in the lower reaches”. The ecological niche overlap changes from synchronous competition to hierarchical differentiation. The ecological niche suitability shows a transformation of “overall homogeneity but local variation”. (2) Qinghai and Gansu belong to subspace I of ecological niches; the strategies of ecological niche specialization, potential ecological niche and ecological niche synergy are appropriate. Shanxi, Inner Mongolia and Ningxia belong to subspace III; the strategies of ecological niche specialization, ecological niche separation, potential ecological niche and ecological niche synergy are suitable. Shandong belongs to subspace VI; the strategies of ecological niche generalization and ecological niche synergy are fitting. Henan, Sichuan and Shaanxi belong to subspace VIII; it is advisable to choose ecological niche generalization, ecological niche separation and ecological niche synergy strategies. The possible marginal contributions of this paper are: (1) applying the idea of fitting optimization to guide the construction of a provincial ecological status indicator system, applying the validation analysis in the SEM model to test the suitability and validity of a provincial ecological status indicator system and improving the scientificity and objectivity of the indicator system construction. (2) Correlating the measurement model with the connotation (state–relationship–function) of the provincial ecological niche, the perspective of ecological niche research and improving the theoretical support for the construction of a multidimensional measurement model. (3) Spatial positioning of provincial ecological niches to improve the relevance and effectiveness of strategies. Full article

Orthotrichum pulchellum is a species of epiphytic moss in which a significant expansion from the oceanic part of Europe to the east of the continent has been observed in the recent two decades. The improvement in air quality in Central and Eastern Europe, but also climate change, probably plays a role in this. This study shows what direction of its spreading we can expect in the future. Ecological niche modeling (ENM) is a widespread method to find out species niches in environmental and geographical space, which allows us to highlight areas that have a higher probability of occurrences of the studied species, based on identifying similar environmental conditions to those already known. We also made predictions for different future scenarios (CMIP5 climatology datasets for the years 2041–2060). Because we were not able to distinguish between historical and newly settled areas, and so, had to use some of the traditional approaches when modeling invasive species, we proposed to use niche clusters based on environmental layers to split the data of all known occurrences and make models separately for each cluster. This approach seems reasonable from the ecological species point of view because using all the morphologically same samples could be misleading. Altogether, 2712 samples were used from three separate niche clusters. For building the models, the Maxent algorithm was used as a well-tested, well-accepted, and commonly used method. Full article

Clarifying the distribution pattern and overlapping relationship of sympatric relative species in the spatio-temporal niche is of great significance to the basic theory of community ecology and integrated management of multi-species habitats in the same landscape. In this study, based on a 9-year dataset (2012–2021) from 493 camera-trap sites in the Gongga Mountain National Nature Reserve, we analyzed the habitat distributions and activity patterns of tufted deer (Elaphodus cephalophus) and sambar (Rusa unicolor). (1) Combined with 235 and 153 valid presence sites of tufted deer and sambar, the MaxEnt model was used to analyze the distribution of the two species based on 11 ecological factors. The distribution areas of the two species were 1038.40 km² and 692.67 km², respectively, with an overlapping area of 656.67 km². Additionally, the overlap indexes Schoener’s D (D) and Hellinger’s-based I (I) were 0.703 and 0.930, respectively. (2) Based on 10,437 and 5203 independent captures of tufted deer and sambar, their daily activity rhythms were calculated by using the kernel density estimation. The results showed that the daily activity peak in the two species appeared at dawn and dusk; however, the activity peak in tufted deer at dawn and dusk was later and earlier than sambar, respectively. Our findings revealed the spatio-temporal niche relationship between tufted deer and sambar, contributing to a further understanding of the coexistence mechanism and providing scientific information for effective wild animal conservation in the reserve and other areas in the southeastern edge of the Qinghai–Tibetan Plateau. Full article

Ecological theory suggests that species with complementary architectural and physiological traits can optimize crown packing to improve resource efficiency and promote ecosystem productivity in forest communities. However, empirical evidence of this prediction is rare in species-rich natural forests, as little is known about how crown spatial complementarity regulates community species richness-productivity relationship (SRPR). In this study, we measured tree architectural traits (stem diameter, height, crown depth and width) for 11,337 trees, and quantified species richness, functional diversity, crown spatial complementarity, soil fertility and forest productivity for 44 quadrats (20 m × 20 m per quadrat) in the Badagongshan 25 ha forest plot, central China. We tested bivariate correlations between species richness, crown complementarity, functional diversity and forest productivity. We employed linear mixed effects models to predict crown complementarity and examined its relationship with functional diversity. Finally, we applied structural equation modeling to quantify the mediation effects of crown complementarity on SRPRs. Species richness promoted crown complementarity and forest productivity. Crown complementarity varied across quadrats, with increases driven primarily by changes in tree height. Crown complementarity was positively related to functional diversity and forest productivity. Species richness increased with soil total phosphorus, while functional diversity decreased with soil bulk density. Forest productivity increased with soil organic carbon and total nitrogen, but decreased with bulk density. Crown complementarity partially mediated the positive effect of species richness on forest productivity, and the mediation effect was mainly through functional diversity. Our results suggest that the crown complementarity index accurately reflects the niche complementarity through light utilization and carbon reallocation. Our study emphasizes that species richness can promote crown complementarity, leading to greater forest productivity, which provides greater insight into the mechanical understanding of the SRPRs. Full article

The quantification of a species’ trophic niche is important to understand the species ecology and its interactions with the ecosystem it resides in. Despite the high frequency of long-finned pilot whale (Globicephala melas edwardii) strandings on the Aotearoa New Zealand coast, their trophic niche remains poorly understood. To assess the isotopic niche of G. m. edwardii within New Zealand, ontogenetic (sex, total body length, age, maturity status, reproductive group) and spatiotemporal (stranding location, stranding event, and stranding year) variation were investigated. Stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) were examined from skin samples of 125 G. m. edwardii (67 females and 58 males) collected at mass-stranding events at Onetahua Farewell Spit in 2009 (n = 20), 2011 (n = 20), 2014 (n = 27) and 2017 (n = 20) and at Rakiura Stewart Island in 2010 (n = 19) and 2011 (n = 19). Variations in δ³⁴S values were examined for a subset of 36 individuals. General additive models revealed that stranding event was the strongest predictor for δ¹³C and δ¹⁵N values, whilst sex was the strongest predictor of δ³⁴S isotopic values. Although similar within years, δ¹³C values were lower in 2014 and 2017 compared to all other years. Furthermore, δ¹⁵N values were higher within Farewell Spit 2017 compared to any other stranding event. This suggests that the individuals stranded in Farewell Spit in 2017 may have been feeding at a higher trophic level, or that the nitrogen baseline may have been higher in 2017 than in other years. Spatiotemporal differences explained isotopic variation of G. m. edwardii in New Zealand waters better than ontogenetic factors. Full article

The sustainability problem of many intangible cultural heritage (ICH) products stems from the shrinking of the core practitioner group, which is also the case for bamboo basketry craft. We believe that the problem in bamboo basketry originated in the lack of labor division between design and manufacturing, which prevents professional designers from entering this industry and results in the absence of several key stakeholders related to innovation and R&D. The lack of labor division is due to the technical difficulties associated with expressing the design concepts. The complexity of basket weaving structures makes it difficult to communicate between designer and manufacturer without precise expression tools, thus binding design and manufacturing into an integrated role. Guided by the user innovation theory, our team studied the design technology of bamboo basketry and developed a series of aiding tools, including the modeling of basic over–under structures and free weaving structures, automatic mapping techniques from 2D to 3D and several frequently used weaving skills, such as connecting, wrapping, plaiting and knotting. This technology enables designers to quickly design and express weaving structures with full details in digital models rather than to make samples. The application of the software shows that the technology considerably improved the designer interest and confidence. This technical solution makes designers, rather than programmers, able to do the development work, which also helps to create a sustainable ecological environment of technological research, also avoiding the difficulties associated with attracting business investment for such niche demands in the starting stage. Our practice shows that the sustainability of ICH products and the sustainability of the industry are closely related and that solving the latter supports the former. Full article

Climate change is a major factor influencing the species distribution and population diversity of living creatures. In this study, the ecological niche model (ENM) MaxEnt was used to evaluate habitat suitability and predict potential habitats of two sympatric fig species, i.e., Ficus squamosa and F. heterostyla, in the Xishuangbanna region of China. Results indicated that mean diurnal range, isothermality, cation exchange capacity (at pH 7), and temperature seasonality were key variables influencing habitat suitability for F. squamosa. However, temperature seasonality and precipitation of the driest quarter showed the greatest contributions to F. heterostyla distribution. During the current period, the habitat suitability distributions of both Ficus species were considerably higher than known occurrences. In the future, potentially suitable distribution areas for both species will reduce overall across the whole study area, although some expansion may occur by 2070. Niche overlap of suitable areas for both species was initially high and then declined in the current period and future epochs in the RCP 2.6 scenario, but increased in the RCP 8.5 scenario. In short, the responses of both Ficus species to climate change differed. Thus, specific actions such as ex situ conservation and assisted migration may be needed to conserve both species. Full article

The oral cavity contains a variety of ecological niches with very different environmental conditions that shape biofilm structure and composition. The space between the periodontal tissue and the tooth surface supports a unique anaerobic microenvironment that is bathed in the nutrient-rich gingival crevicular fluid (GCF). During the development of periodontitis, this environment changes and clinical findings reported a sustained level of calcium ion concentration in the GCF collected from the periodontal pockets of periodontitis patients. Here, we report the effect of calcium ion supplementation on human oral microbial biofilm formation and community composition employing an established SHI medium-based in vitro model system. Saliva-derived human microbial biofilms cultured in calcium-supplemented SHI medium (SHICa) exhibited a significant dose-dependent increase in biomass and metabolic activity. The effect of SHICa medium on the microbial community composition was evaluated by 16S rRNA gene sequencing using saliva-derived microbial biofilms from healthy donors and periodontitis subjects. In this study, intracellular microbial genomic DNA (iDNA) and extracellular DNA (eDNA) were analyzed separately at the genus level. Calcium supplementation of SHI medium had a differential impact on iDNA and eDNA in the biofilms derived from healthy individuals compared to those from periodontitis subjects. In particular, the genus-level composition of the eDNA portion was distinct between the different biofilms. This study demonstrated the effect of calcium in a unique microenvironment on oral microbial complex supporting the dynamic transformation and biofilm formation. Full article

Forecasting the distribution patterns of invasive weed species under changing climate conditions is critical for the early identification of especially vulnerable regions and the implementation of effective preventive measures. In this study, the current and potential range of stranglewort (Cynanchum acutum L.)—an invasive alien species (IAS) in certain regions—are predicted under various climate scenarios, using the maximum entropy algorithm. Species occurrence data representing the natural distribution of C. acutum and 15 of the WorldClim bioclimatic variables are used. With an ensemble method, the impact of climate change on the distribution of the species is predicted according to five CMIP6 climate change models and three scenarios (optimistic: SSP245; middle of the road: SSP370; and pessimistic: SSP585). According to the findings, it is predicted in all scenarios that C. acutum could expand its range to the north, particularly in agricultural landscapes. Therefore, the invasive status of this species will likely continue in the future. This emphasizes the need to determine the priority of conservation targets, especially for agricultural areas, to ensure food safety and protect biodiversity. Full article

Rockfish (genus Sebastes) assemblages can inform mechanisms of coexistence and maintenance of diversity in ecological communities. Coexistence theory characterizes ecological assemblages as following either a deterministic niche differentiation model, or a stochastic lottery model. We used natural abundances of carbon and nitrogen stable isotopes from the tissues of ten co-occurring species of rockfish to assess position, size, and overlap of trophic niches in this diverse assemblage. We created a stochastic null model and compared observed values against the null model to determine if patterns were consistent with a deterministic or a stochastic model. We classified rockfish species as either demersal or pelagic. Mean δ13C and δ15N values differed among pelagic and demersal rockfish species and mean position was more variable than what was predicted by our null model. All species had relatively small trophic niches compared to occupied trophic niche space for the entire assemblage and trophic niche size was smaller than what was predicted by our null model. Trophic niche overlaps varied from 32% to 189% but were substantially lower than predicted by our null mode. All observed trophic niche metrics were different than the stochastic null model. This rockfish assemblage follows a deterministic model of community composition. Full article