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China’s environmental problems are emerging with the continuous development of the economy and urbanization. The study of the impact of urban spatial structure on environmental efficiency has important significance concerning exploring ways to reduce the environmental cost of economic activity. Based on the fusion-corrected DMSP-OLS and NPP-VIIRS nighttime light data, this paper constructs spatial structure indicators of 276 prefecture-level cities and then empirically tests the impact of urban spatial structure on environmental efficiency using a fixed-effects model. The results show that: 1) The monocentric spatial structure has higher environmental efficiency than the polycentric spatial structure. 2) The mechanism analysis shows that the monocentric spatial structure could improve environmental efficiency through learning, sharing, and matching. 3) Population size and density have a robust moderating effect that when the resident population size of a city is more than 5 million or the population density is beyond 280 persons/km 2 , the monocentric spatial structure has a negative impact on environmental efficiency. In contrast, the polycentric spatial structure is more effective. 4) The point-based household registration policy adopted by the government to control population size has no significant impact on environmental efficiency, while the environmental information disclosure policy can effectively play a role. Our findings provide a basis for the Chinese government to formulate urban planning and environmental protection policies and offer the experience to other developing countries.

This study attempts to form a typology of metropolitan spatial structure. In order to achieve this goal, we reviewed the studies carried out in this field through a systematic review. The statistical population of this study consists of English-based scientific articles published in prestigious scientific journals from 1980 to 2019, which were obtained through a search in scientific information databases and by using keywords related to the metropolitan spatial structure. After searching for related studies and based on the relationship between the title, keywords, content, and citation, 175 articles were selected and carefully examined. The results show that the metropolitan spatial structures can be categorized into 4 main patterns of “convergent, divergent, homogenous, and heterogeneous” according to centripetal–centrifugal and concentrated–deconcentrated forces. In accordance with these patterns, 23 subpatterns were identified. This article provides a new typology for a deeper understanding of the metropolitan spatial structure and opens a new window for theorizing and presenting a useful guide for policy-makers and spatial planners in the debate of spatial patterns knowledge.

Forest aboveground biomass (AGB) serves as a crucial indicator of productivity and carbon storage capacity. While the impact of stand structure on AGB is well-documented for pure moso bamboo stands, the specific structural factors influencing AGB and the mechanisms driving these effects in mixed moso bamboo forests, characterized by species diversity and structural complexity, require further elucidation. This study analyzed 9453 bamboos and arbor trees within the TianBao MetaPlot, which were tessellated into 108 standard plots in Tianbaoyan National Nature Reserve, Fujian, China. Using a multi-method voting approach, we identified the key structural factors influencing stand AGB and employed Partial Least Squares Path Modeling (PLS-PM) to assess their direct and indirect effects. We found that the stand density, moso bamboo mixing ratio, Shannon’s index, Simpson’s index, mean tree height, openness, and tree size variation coefficient were the key structural factors influencing the stand AGB. The PLS-PM analysis showed that stand density had a negative effect on stand AGB, which can be explicitly decomposed through a direct negative effect and an indirect negative effect. Tree diversity showed a strong positive effect, supporting the niche complementarity theory. The stand mean tree height and stand tree size variation had positive effects on stand AGB, while stand openness had a negative effect. The direct effects of tree diversity, stand mean tree height, and stand openness were stronger than the indirect effects on stand AGB, while the indirect effect of stand density was greater than the aforementioned effects. These results highlight the complex interactions between stand structure and stand AGB in mixed moso bamboo forests. The negative effect of stand density on stand AGB is in contrast with previous findings on arbor forests, wherein a higher stand density often promotes AGB, highlighting the unique structural characteristics of mixed moso bamboo forests. To promote biomass accumulation and enhance carbon sequestration in mixed moso bamboo stands, it is recommended to increase the tree size variability, enhance the tree species diversity, and apply rational thinning of moso bamboo, based on site-specific conditions.

The stand structure of ancient tea tree (Camellia taliensis) communities is critical for maintaining their structural and functional stability. Therefore, this study employed backpack laser scanning (BLS) technology to extract individual tree parameters (diameter at breast height, tree height, relative coordinates, etc.) in seven sample plots (25 m × 25 m each) to analyze their spatial and non-spatial structure characteristics. Firstly, the accuracy of diameter at breast height (DBH) and tree height (TH) estimations using BLS resulted in a root mean square error (RMSE) of 4.247 cm and 2.736 m and a coefficient of determination (R2) of 0.948 and 0.614, respectively. Secondly, in this community, trees exhibited an aggregated spatial distribution (average uniform angle > 0.59), with small differences in DBH among adjacent trees (average dominance > 0.48) and a high proportion of adjacent trees belonging to different species (average mingling > 0.64). Ancient tea trees in the 5–15 cm diameter class face considerable competitive pressure, with values ranging from 14.28 to 179.03. Thirdly, this community exhibits rich species composition (more than 7 families, 8 genera, and 10 species, respectively), strong regeneration capacity (with an inverse J-shaped diameter distribution), uniform species distribution (Pielou evenness index > 0.71), and high species diversity (with a Shannon–Wiener diversity index ranging from 1.65 to 2.47 and a Simpson diversity index ranging from 0.71 to 0.91), and the ancient tea trees maintain a prominent dominant status and important value ranging from 19.36% to 49%. The results indicate that, under the current conditions, the structure and function of this community collectively exhibit relatively stable characteristics. BLS provides a powerful tool for the research and conservation of rare and endangered species.

This study used spatial interaction modeling to examine whether origin-specific and destination-specific factors, distance decay effects, and spatial structures explain the criminal trips of residential burglars. In total, 4041 criminal trips committed by 892 individual offenders who lived and committed residential burglary in Tokyo were analyzed. Each criminal trip was allocated to an origin–destination pair created from the combination of potential departure and arrival zones. The following explanatory variables were created from an external dataset and used: residential population, density of residential burglaries, and mobility patterns of the general population. The origin-specific factors served as indices of not only the production of criminal trips, but also the opportunity to commit crimes in the origin zones. Moreover, the criminal trips were related to the mobility patterns of the general population representing daily leisure (noncriminal) trips, and relatively large origin- and destination-based spatial spillover effects were estimated. It was shown that considering not only destination-specific but also origin-specific factors, spatial structures are important for investigating the criminal trips of residential burglars. The current findings could be applicable to future research on geographical profiling by incorporating neighborhood-level factors into existing models.

Sex‐biased dispersal is common in many animals, with male‐biased dispersal often found in studies of mammals and reptiles, including interpretations of spatial genetic structure, ostensibly as a result of male–male competition and a lack of male parental care. Few studies of sex‐biased dispersal have been conducted in turtles, but a handful of studies, in saltwater turtles and in terrestrial turtles, have detected male‐biased dispersal as expected. We tested for sex‐biased dispersal in the endangered freshwater turtle, the spotted turtle (Clemmys guttata) by investigating fine‐scale genetic spatial structure of males and females. We found significant spatial genetic structure in both sexes, but the patterns mimicked each other. Both males and females typically had higher than expected relatedness at distances <25 km, and in many distance classes greater than 25 km, less than expected relatedness. Similar patterns were apparent whether we used only loci in Hardy–Weinberg equilibrium (n = 7) or also included loci with potential null alleles (n = 5). We conclude that, contrary to expectations, sex‐biased dispersal is not occurring in this species, possibly related to the reverse sexual dimorphism in this species, with females having brighter colors. We did, however, detect significant spatial genetic structure in males and females, separate and combined, showing philopatry within a genetic patch size of <25 km in C. guttata, which is concerning for an endangered species whose populations are often separated by distances greater than the genetic patch size. Sex‐biased dispersal is common in many animals, with male‐biased dispersal often found. We found significant spatial genetic structure in both sexes, but male and female dispersal patterns mimicked each other, with higher than expected related at distances <25 km. Lack of male‐biased dispersal was surprising, but a genetic patch size of <25 km is concerning for an endangered species whose populations are often separated by large distances.

Intrastrain genetic and phenotypic diversity within Pseudomonas aeruginosa populations is common in chronic pulmonary infections. While this intrastrain heterogeneity is a hallmark of chronic infection, its consequences for the spatial organization of P. aeruginosa within the airways remain unclear. Here, we demonstrate that the loss of O-specific antigen in a subpopulation of P. aeruginosa significantly alters the spatial architecture of P. aeruginosa , without changing the total population size or composition. Using a combination of tissue clearing and hybridization chain reaction RNA-FISH in a murine lung infection model, we mapped the localization of genetically distinct P. aeruginosa variants in mixed populations in vivo . These findings reveal that genetic diversification within a strain can reshape the infection landscape at the micron scale, highlighting the overlooked role of intrastrain dynamics in shaping the microbiogeography of infections and influencing host-pathogen interactions.

Species spatial distributions are the result of population demography, behavioral traits, and species interactions in spatially heterogeneous environmental conditions. Hence the composition of species assemblages is an integrative response variable, and its variability can be explained by the complex interplay among several structuring factors. The thorough analysis of spatial variation in species assemblages may help infer processes shaping ecological communities. We suggest that ecological studies would benefit from the combined use of the classical statistical models of community composition data, such as constrained or unconstrained multivariate analyses of site-by-species abundance tables, with rapidly emerging and diversifying methods of spatial pattern analysis. Doing so allows one to deal with spatially explicit ecological models of beta diversity in a biogeographic context through the multiscale analysis of spatial patterns in original species data tables, including spatial characterization of fitted or residual variation from environmental models. We summarize here the recent progress for specifying spatial features through spatial weighting matrices and spatial eigenfunctions in order to define spatially constrained or scale-explicit multivariate analyses. Through a worked example on tropical tree communities, we also show the potential of the overall approach to identify significant residual spatial patterns that could arise from the omission of important unmeasured explanatory variables or processes.

Taking metropolitan areas as space carriers has become the engine of the Chinese government in its promotion of high-quality development, and this has also become an important measure by which to balance regional development. We used Zipf’s law and the gravity model to study the urban scale distribution characteristics of the Kashgar Metropolitan Area (KMA) in this paper. We also constructed a spatial structure judgment vector for the KMA and put forward the development objectives of different circles. The findings show the following: (1) large cities have a high primacy of development, while small and medium-sized cities are underdeveloped. At present, the KMA is a concentrated monocentric-pattern metropolitan area, with Kashgar City as its core city. (2) The urban built-up area of Kashgar City is expanding to the east and south, where it has broken through the administrative boundary and become integrated with the urban built-up area of Shule County. The spatial structure characteristics of the KMA have been further clarified. The KMA forms three circles: core, middle, and outer. (3) Tumxuk City, Bachu County, Yecheng County, Shache County, and other counties are far from the core city and cannot be connected with Kashgar, but they are closely related to the surrounding cities, forming the Bachu–Tumxuk Urban Group and the Shache–Zepu–Yecheng Urban Group. This study contributes to the understanding of the characteristics of urban scale distribution and the spatial structure of metropolitan areas in arid regions, as well as providing guidance for the formulation of policies for the development of different circles in the KMA.

Description of the subject. The study of the spatial distribution of trees provides information on species ecology and forest dynamics. Such knowledge is important for the sustainable management of large African trees, including Prioria balsamifera (Vermoesen) Breteler and Prioria oxyphylla (Harms) Breteler. Objectives. This study aimed to (i) characterize the spatial distribution patterns of P. balsamifera and P. oxyphylla, (ii) highlight their intraspecific and interspecific relationships, and (iii) identify environmental factors that may explain their spatial structure. Method. Univariate and bivariate pair correlation functions were used to characterize spatial distribution patterns. Generalized linear models with a Poisson distribution, together with toroidal shift randomization tests, were applied to assess the effects of environmental factors on the spatial structure of Prioria. Results. Each Prioria species exhibits an aggregated spatial structure and spatial autocorrelation of trunk diameters, while sharing the same microhabitat. Their coexistence may be facilitated by functional trait differentiation, with P. balsamifera and P. oxyphylla displaying acquisitive and conservative resource-use strategies, respectively. An attraction between juveniles and adults of P. balsamifera was observed within a 500 m radius, with a less pronounced trend in P. oxyphylla. Finally, the abundance of individuals of both P. balsamifera and P. oxyphylla is significantly related to altitude. Conclusions. This study shows that the spatial distribution of these two Prioria species is linked to altitude, and that their coexistence is facilitated by some degree of ecological niche differentiation.