Nearest-neighbor Distance Analysis Research Articles

Spatial and temporal assessment of snake encounters in urban Delhi, India

Delhi, the capital city of India is, highly urbanized and surrounded by remnant forest, farms, ridges, and other green areas experience regular snake encounters in and around residential, institutional, and industrial areas. A total of 41 months of sampling from January 2019 to May 2022 was conducted wherein we, studied the snake assemblage in Delhi to determine the species composition, encounter frequency, seasonal activity patterns, and probable encounter sites in an urban setup. We documented 372 individuals belonging to 15 species from seven families out of 23 species found in Delhi. Snakes were found inside forests, public parks, homes, drain networks, streets, office buildings, and even in school-college buildings. The most recorded species being Ptyas mucosa (37.37%, n = 139), Naja naja (19.62%, n = 73), and Lycodon aulicus (13.44%, n = 50). The highest numbers of incidents were reported in the month of July (22.04%, n = 82) and August (19.89%, n = 74) during the peak monsoon season, for identifying high encounter sites, we used a geostatistical modeling tool, Ordinary kriging to identify places having more snake occurrences. We further used a statistical spatial method called average nearest neighbor distance to detect the pattern distribution of snake species. Spatial interpolation done through Ordinary kriging highlighted two areas having concentrated snake encounters. The results of the average nearest neighbor distance analysis showed three species having clustered and two species having dispersed distribution. The incidence of snake encounters was found to be highly seasonal and appeared to be associated mainly with monthly rainfall, temperature, and humidity. The findings of this study on snakes’ distribution patterns provide valuable insights into the conservation of these species. Understanding their habitat preferences and spatial distribution is crucial for the implementation of effective conservation strategies.

How to Survive Intensive Harvesting: The High Recruitment Rates of the Precious Mediterranean Red Coral (Corallium rubrum L. 1758)

The recruitment process is a fundamental step in population life cycles that determines survival, population demographic structure, and dynamics. The success of recruitment events repeated over successive years greatly affects the survival of long-lived gorgonian populations. Here, we report the recruitment process of the precious, heavily harvested Mediterranean gorgonian Corallium rubrum (red coral) on both settlement tiles and natural substrates over different Mediterranean areas. Red coral is a gonochoric internal brooder that reproduces in early summer. Lecithotrophic planulae settle 15–30 days after release in semi-dark environments at depths between 15 and 800 m. In autumn, 0.58–0.68 mm-wide recruits can be observed on the vaults of small crevices and caves and on rocky cliffs and boulders. Owing to their small size, there is limited knowledge of C. rubrum recruitment in the field. In this study, we examined the recruitment density and distribution in Canadells (Banyuls sur Mer, France) and Calafuria (Livorno, Italy) and compared these findings with those collected over different Mediterranean areas. Red coral exhibited high recruitment values ranging from 0.43 to 13.19 recruits dm−2. The distribution pattern of recruits, examined at a small spatial scale via nearest-neighbor distance analysis, revealed a significantly higher patch frequency on the natural substrate than on settlement tiles, presumably because of the scarcely available spots of free space on the former substrate, which are crowded by competitor species.

The Spatio-Temporal Patterns and Influencing Factors of Different New Agricultural Business Entities in China—Based on POI Data from 2012 to 2021

The high-quality development of new agricultural business entities (NABEs) is an important driving force for realizing rural revitalization and accelerating the modernization of agriculture and rural areas. The main purpose of the study is to investigate the spatial distribution pattern, aggregation scales, development mechanism, and internal differences of various types of NABEs in different regions. It provides targeted ideas for alleviating regional differences in the development of NABEs in different agricultural regions. Kernel density estimation, nearest neighbor distance analysis, Tyson’s polygon coefficient of variation, and Ripley’s K function are used to study the spatial and temporal evolution, spatial aggregation, and scale divergence of various types of NABEs, and Pearson correlation analysis is incorporated to explore the specific factors affecting the development of various types of NABEs. The study results: First, family farms are the most widely distributed, and agricultural enterprises are the most sparsely distributed, being distributed “more in the southeast and less in the northwest” in all three categories. Second, the strongest aggregation scales of different NABEs are increasing, and the strongest aggregation scales of agricultural enterprises are larger than those of family farms and cooperatives in all agricultural areas. Third, the development of specialized farmers’ cooperatives (abbreviated as ‘cooperatives’) is more constrained by traditional agricultural inputs and is a kind of agricultural input-oriented development. Family farms are more constrained by the living standards of rural residents in the region and are a kind of rural economy-oriented development. Agricultural enterprises are more subject to the economic level of the region, which is a kind of market economy-oriented development. Finally, in the process of developing NABEs, regional differences should be emphasized, and a small number of agriculturally leading enterprises and model cooperatives should drive a large number of small-scale family farms and smallholder farmers in order to become a characteristic path for China’s agricultural development.

Chemical and Structural Alterations in the Amorphous Structure of Obsidian due to Nanolites.

Obsidian is volcanic glass that results from the rapid cooling of silica-rich melt. Nanoscale crystallites precipitate out of the melt prior to solidification and remain embedded in the amorphous matrix. These crystallites provide information on the flow kinetics and composition of the melt. Due to the sparsity and size of nanolites, studies often focus on supramicron crystallites. This research takes advantage of the conchoidal fracture of obsidian by knapping samples with nanometer-thin edges for transmission electron microscopy characterization. Nanolites in the amorphous matrix are studied using energy-dispersive spectroscopy (EDS) and electron diffraction. Certain alkali and alkaline-earth cations exhibit patterns of depletion near Fe-oxide nanolites. EDS is used to identify nanolites and variations in the composition of the matrix. Parallel beam diffraction and radial distribution function analysis of nearest-neighbor distances determine average bond lengths in the matrix near nanolites, showing that nanolites influence the nearby short-range ordering and atomic character of the matrix. Analysis reveals decreased mean nearest-neighbor distances in the matrix adjacent to nanolites compared to the bulk. Our methods exhibit the required sensitivity to detect variations in the composition and structure near nanolites, and our findings indicate that obsidian nanolites contribute to quantifiable localized changes in the amorphous structure.

Spatiotemporal Clustering of Seismicity During the 2018 Kilauea Volcanic Eruption

AbstractThe intense volcanic and seismic activity at Kilauea volcano, Hawaii in 2018 provides an opportunity to understand the characteristics and driving forces of volcano earthquake clusters. Nearest neighbor distance analysis of a high‐resolution earthquake catalog reveals two modes of clustering: M1 and M2. M1 clusters focus on events within short space and time windows, and are concentrated within isolated fault patches. Examination of three structures shows a gradual increase of source radius (assuming a constant stress drop) and spatial migration of seismicity, likely representing aseismic growth of peripheral faults. M2 clusters focus on temporal clustering of all seismicity within the caldera and most clusters represent complete seismicity cycles between major collapse events. Beginning in late June, the M2 cluster duration gradually increased. The event numbers show a strong linear relationship with the tilt rates on the transverse component, suggesting earthquake rates are controlled by the deformation rate within the caldera.

Dual-color dSTORM imaging and ThunderSTORM image reconstruction and analysis to study the spatial organization of the nuclear phosphatidylinositol phosphates

Single molecule localization microscopy (SMLM) provided an unprecedented insight into the sub-nuclear organization of proteins and nucleic acids but apart from the nuclear envelope the role of the nuclear lipids in the functional organization of the cell nucleus was less studied. Nevertheless, nuclear lipids and specifically phosphatidylinositol phosphates (PIPs) play increasingly evident roles in gene expression. Therefore, here we provide the SMLM-based approach for the quantitative evaluation of the nuclear PIPs distribution while preserving the context of nuclear architecture. Specifically, on the example of phosphatidylinositol 4,5-bisphosphate (PIP2) we have:•Implemented and optimized the dual-color dSTORM imaging of nuclear PIP2.•Customized the Nearest Neighbor Distance analysis using ImageJ2 plug-in ThunderSTORM to quantitatively evaluate the spatial distribution of nuclear PIP2.•Developed an ImageJ2 tool for the visualization of the Nearest Neighbor Distance analysis results in cellulo.Our customization of the dual-color dSTORM imaging and quantitative analysis provide a tool that is independent of but complementary to the biochemical and lipidomic analyses of the nuclear PIPs. Contrary to the biochemical and lipidomic analyses, the advantage of our analysis is that it preserves the spatial context of the nuclear PIP distribution.

Quantitative Analysis of Spatial Distribution Characteristics of Traditional Villages in Hunan Province

This study takes 658 traditional villages in Hunan province as the research object. Relying on ArcGIS geographic information system, the traditional villages in Hunan province were abstracted into point sets with attribute information. By means of average nearest neighbor distance analysis, kernel density analysis and intercity distribution comparison, the basic geographical characteristics of traditional villages in Hunan province were summarized, that is, significant agglomeration distribution, three agglomeration areas and uneven intercity distribution. Multiple types of natural geographical factors were superimposed, such as elevation, slope aspect, slope, river, water systems, annual precipitation and annual average temperature, so as to analyze the impact of elevation topography, river system and climate conditions on village site selection. With the help of geographic detector tool, the correlation between elevation, slope, water system, annual average temperature, annual precipitation and village distribution was quantitatively analyzed. Through the analysis of correlation degree, interaction and single factor characteristics, it is concluded that natural geographical factors are related to village distribution and multiple factors interact with each other. Based on the quantitative analysis of interactions between traditional villages and the natural environment, the distribution characteristics of traditional villages have been summarized, providing reference for the subsequent systematic research and protection of traditional villages.

Aggregation Site Choice by Gregarious Nymphs of the Desert Locust, Schistocerca gregaria, in the Sahara Desert of Mauritania.

Animals often aggregate at certain sites during vulnerable periods such as night-roosting as an anti-predatory strategy. Some migratory gregarious animals must regularly find new night-roosting sites, but how they synchronously choose such sites is poorly understood. We examined how gregarious nymphs of the desert locust, Schistocerca gregaria Forskål (Orthoptera: Acrididae), aggregate at certain plants for night-roosting in the Sahara Desert. Migratory bands of last instar nymphs climbed trees around dusk and roosted there overnight. A spatial autocorrelation analysis of plants indicated that the larger locust groups formed at the larger plants within the local plant community. Other large groups were not formed near the large tree, but smaller groups were patchily distributed. Plant height was the primary cue used by migratory bands to choose night-roosting plants. A nearest-neighbor distance analysis showed that single conspicuous large trees with scattered smaller plants were distributed locally. This plant community structure and negative geotactic ascending behavior of gregarious nymphs may force them to concentrate at the landmark plant from all directions and afar. This plant-size-dependent roosting site choice may contribute for developing artificial trapping systems for locusts and inciting to a new environment-friendly night control approach.

Quantitative Analysis of the Spatial Organization of Synaptic Inputs on the Postsynaptic Dendrite.

The spatial organization of synaptic inputs on the dendritic tree of cortical neurons is considered to play an important role in the dendritic integration of synaptic activity. Active electrical properties of dendrites and mechanisms of dendritic integration have been studied for a long time. New technological developments are now enabling the characterization of the spatial organization of synaptic inputs on dendrites. However, quantitative methods for the analysis of such data are lacking. In order to place cluster parameters into the framework of dendritic integration and synaptic summation, these parameters need to be assessed rigorously in a quantitative manner. Here I present an approach for the analysis of synaptic input clusters on the dendritic tree that is based on combinatorial analysis of the likelihoods to observe specific input arrangements. This approach is superior to the commonly applied analysis of nearest neighbor distances between synaptic inputs comparing their distribution to simulations with random reshuffling or bootstrapping. First, the new approach yields exact likelihood values rather than approximate numbers obtained from simulations. Second and more importantly, the new approach identifies individual clusters and thereby allows to quantify and characterize individual cluster properties.

Linking intraspecific trait variability and spatial patterns of subtropical trees

The importance of intraspecific trait variability (ITV) to the spatial distribution of individual species is unclear. We hypothesized that intraspecific trait dispersions underlying niche processes deviate more from null model expectations, by reducing their spread (range and variance), kurtosis, and standard deviation of near-neighbor distance, for species with aggregated than those with random distributions. The link between species' spatial distributions and ITV patterns was examined using an individual tree-based trait data set, in which specific leaf area, mean leaf area, leaf dry matter content, and diameter at breast height were measured for 18,773 stems of 45 species in a 4.84ha mapped subtropical forest plot in China. The nearest-neighbor distance analysis showed that, of 45 species, 14 species were distributed in random and 31 species were distributed in aggregation, while no species was distributed in uniform in the plot. The dispersions of all studied traits in species with an aggregated distribution on average deviated more strongly from the null expectation than those in species with a random distribution and that the extent of deviation was negatively associated with the degree of spatial randomness across species. Our results indicate that niche processes are primarily responsible for the spatial structure of species with aggregated distributions, while stochastic processes drive those with random distributions. Our results highlight the fundamental role of ITV in shaping spatial patterns of co-existing species.

Spatial analysis of data frequency and severity of rural accidents

In this paper, to study the frequency and severity of traffic accidents, a combination of geographic information system and spatial analysis has been used. For this purpose, methods of planar and network statistics including kernel density estimation and nearest neighbor distance analysis were applied for three types of accidents including fatal, injury, and material property damages. In addition, drawbacks of the traditional planar point pattern and the benefits of network analysis are offered. The network statistics are executed through SANET version 4 and ArcMap on the Semnan–Garmsar road in Iran. The nearest neighbor output analysis is consist of four curves, and regarding the fact that the amounts for accidents resulting in fatalities, injuries, and damages, the observed value curve is above the 5% confidence interval; accidents in the study region are more clustered than would be expected by random chance.

Motor Bearing Fault Detection Using Spectral Kurtosis-Based Feature Extraction Coupled With K-Nearest Neighbor Distance Analysis

Bearing faults are the main contributors to the failure of electric motors. Although a number of vibration analysis methods have been developed for the detection of bearing faults, false alarms still result in losses. This paper presents a method that detects bearing faults and monitors the degradation of bearings in electric motors. Based on spectral kurtosis (SK) and cross correlation, the method extracts fault features that represent different faults, and the features are then combined to form a health index using principal component analysis (PCA) and a semisupervised k-nearest neighbor (KNN) distance measure. The method was validated by experiments using a machinery fault simulator and a computer cooling fan motor bearing. The method is able to detect incipient faults and diagnose the locations of faults under masking noise. It also provides a health index that tracks the degradation of faults without missing intermittent faults. Moreover, faulty reference data are not required.

Lck is Randomly Distributed on the T Cell Plasma Membrane

The spatial organization of signaling components on the T cell plasma membrane is generally believed to regulate T cell function. During activation, local immobilization in so-called microclusters and subsequent rearrangement of key components of the T cell signaling machinery results in down-stream signaling and T cell activation1. Using super-resolution microscopy, a number of reports have proposed the existence of nanoscopic clusters of T cell signaling components2-4, suggesting that local enrichment of signaling molecules is an underlying regulatory mechanism of T cell signaling. Here, we investigate more in detail the nanoscopic organization of Lck in Jurkat T cells. Contrary to a previous report that described Lck nano-clusters using PALM, we find both in PALM and dStorm experiments that Lck is homogeneously distributed on the T cell plasma membrane. We develop a new approach to analyze apparent nano-clustering in PALM and dStorm data of fixed cell samples. By titrating the labeling density, we calculate cluster sizes and localization densities in clusters to distinguish random from clustered spatial distributions of molecules. Moreover, we also use two-color labeling in combination with nearest neighbor distance analysis to characterize the spatial distribution of molecules. Our data suggest that Lck activity and hence T cell activation cannot depend on the formation of nanoscopic clusters. Rather, our data support the view that Lck is randomly distributed on the T cell plasma membrane and is specifically recruited to signaling hotspots during T cell activation. Funding: Austrian Science Fund/FWF P 27941-B28 1. Dustin M.L. (2014) Cancer Immunol Res 2. Owen D.M. et al (2012) Nat Commun 3. Rossy J. et al (2013) Nat Immunol 4. Lillemeier B.F.F. et al (2010) Nat Immunol

CPTED기법을 통한 모니터링 시스템 설치위치 시각화 결정법

Needs about safety of residents are important in urbanized society, elderly and small-size family. People are looking for safety information system and device of CPTED. That is, Needs and Installations of CCTV increased steadily. But, scientific analysis about validity, systematic plan and location of security CCTV is nonexistent. It is simply put these devised in more demanded areas. It has limits to look for safety of residents by increasing density of CCTVs. One of the characteristics of crime is clustering and stong interconnectivity. So, exploratory spatial data of crime is geo-coded using 2 years data and carried out cluster analysis and space statistical analysis through GIS space analysis by dividing 18 variables into social economy, urban space, crime prevention facility and crime occurrence index. The result of analysis shows cluster of 5 major crimes, theft, violence and sexual violence by Nearest Neighbor distance analysis and Ripley`s K function. It also shows strong crime interconnectivity through criminal correlation analysis. In case of finding criminal cluster, you can find criminal hotspot. So, in this study I found concept of hotspot and considered technique about selection of hotspot. And then, selected hotspot about 5 major crimes, theft, violence and sexual violence through Nearest Neighbor Hierarchical Spatial Clustering.

DNA barcodes discriminate freshwater fishes from the Paraíba do Sul River Basin, São Paulo, Brazil

Background and aims: Considering the promising use of DNA barcoding for species identification, the importance of the freshwater fish fauna of the Paraíba do Sul River Basin, and its advanced stage of degradation, the present study evaluated the effectiveness of DNA barcoding to identify the fish species in this basin.Materials and methods: A total of 295 specimens representing 58 species belonging to 40 genera, 17 families, and 5 orders were sequenced.Results: The DNA barcodes discriminated all species analyzed without ambiguity. The results showed a pronounced difference between conspecific and congeneric pair-wise sequence comparisons, demonstrating the existence of a “barcode gap” for the species analyzed. The nearest-neighbor distance analysis showed only three cases with Kimura two-parameter values lower than a 2% divergence threshold. However, the patterns of divergence observed in each case remained sufficient to discriminate each species, revealing the accuracy of DNA barcoding even cases with relatively low genetic divergence. At the other extreme, three species displayed high genetic sequence divergence among conspecifics. For two cases, Characidium alipioi and Geophagus proximus, barcoding proved effective at flagging possible new species. For another case, Astyanax bimaculatus, the use of DNA barcoding of the comparison of shared freshwater fish fauna between different basins revealed itself as highly useful in disclosing that the previously identified A. bimaculatus “cluster A” probably represents the species Astyanax altiparanae.Conclusion: The present study is among the first to assess the efficiency of barcoding for the Brazilian freshwater fishes. The results demonstrate the utility of barcoding to identify the fauna from this basin, contribute to an enhanced understanding of the differentiation among species, and to help flag the presence of overlooked species.

A VERY LARGE TELESCOPE/NACO STUDY OF STAR FORMATION IN THE MASSIVE EMBEDDED CLUSTER RCW 38

We present adaptive optics (AO) near-infrared (JHKs) observations of the deeply embedded massive cluster RCW 38 using NACO on the VLT. Narrowband AO observations centered at wavelengths of 1.28, 2.12, and 2.17 micron were also obtained. The area covered by these observations is about 0.5 pc square, centered on the O star RCW 38 IRS2. We use the JHKs colors to identify young stars with infrared excess. Through a detailed comparison to a nearby control field, we find that most of the 337 stars detected in all three infrared bands are cluster members (~317), with essentially no contamination due to background or foreground sources. Five sources have colors suggestive of deeply embedded protostars, while 53 sources are detected at Ks only; their spatial distribution with respect to the extinction suggests they are highly reddened cluster members. Detectable Ks-band excess is found toward 29 +/- 3 % of the stars. For comparison to a similar area of Orion observed in the near-infrared, mass and extinction cuts are applied, and the excess fractions redetermined. The resulting excesses are then 25 +/- 5 % for RCW 38, and 42 +/- 8 % for Orion. RCW 38 IRS2 is shown to be a massive star binary with a projected separation of ~500 AU. Two regions of molecular hydrogen emission are revealed through the 2.12 micron imaging. One shows a morphology suggestive of a protostellar jet, and is clearly associated with a star only detected at H and Ks, previously identified as a highly obscured X-ray source. Three spatially extended cometary-like objects, suggestive of photoevaporating disks, are identified, but only one is clearly directly influenced by RCW 38 IRS2. A King profile provides a reasonable fit to the cluster radial density profile and a nearest neighbor distance analysis shows essentially no sub-clustering.

Digital holographic microscopy reveals prey-induced changes in swimming behavior of predatory dinoflagellates

The shallow depth of field of conventional microscopy hampers analyses of 3D swimming behavior of fast dinoflagellates, whose motility influences macroassemblages of these cells into often-observed dense "blooms." The present analysis of cinematic digital holographic microscopy data enables simultaneous tracking and characterization of swimming of thousands of cells within dense suspensions. We focus on Karlodinium veneficum and Pfiesteria piscicida, mixotrophic and heterotrophic dinoflagellates, respectively, and their preys. Nearest-neighbor distance analysis shows that predator and prey cells are randomly distributed relative to themselves, but, in mixed culture, each predator clusters around its respective prey. Both dinoflagellate species exhibit complex highly variable swimming behavior as characterized by radius and pitch of helical swimming trajectories and by translational and angular velocity. K. veneficum moves in both left- and right-hand helices, whereas P. piscicida swims only in right-hand helices. When presented with its prey (Storeatula major), the slower K. veneficum reduces its velocity, radius, and pitch but increases its angular velocity, changes that reduce its hydrodynamic signature while still scanning its environment as "a spinning antenna." Conversely, the faster P. piscicida increases its speed, radius, and angular velocity but slightly reduces its pitch when exposed to prey (Rhodomonas sp.), suggesting the preferred predation tactics of an "active hunter."

A quantitative method for assessing co-localization in immunolabeled thin section electron micrographs

A method is introduced for the analysis of nearest neighbor distances between immunogold particles marking proteins on electron micrographs. Deviation from the distribution that is predicted by chance indicates co-localization of the labeled species, and the potential for productive interaction in vivo. Application of this method to the analysis of nearest neighbor distances in experiments with pea leaf thin sections and isozyme-directed antibodies indicates that glyceraldehyde-3-P dehydrogenase is located near P-glycerate kinase and near aldolase in the chloroplast stroma, consistent with the notion that these enzymes are part of a multi-enzyme photosynthetic CO 2-fixation complex in situ.

Nearest-Neighbor Analysis of Trilobite Morphospace

-Previous observations indicate that morphologic distinctness of suprageneric taxa (superfamilies, suborders, and orders) of trilobites increased during their Cambro-Ordovician diversification. Analysis of nearest-neighbor distances (NNDs) among trilobites in morphospace is used to test the robustness of this pattern while avoiding the overprint of higher-level taxonomy. The properties of the uniform distribution are used to determine the bounds of the morphospace, and computer simulation of random points is used to circumvent edge effects in the analysis of NNDs. Observed NNDs became significantly smaller relative to expected distances, supporting the hypothesis that morphospace became more discontinuously occupied from the Cambrian to the Ordovician. However, absolute NNDs (not considered relative to expected NNDs) actually increased. Therefore, the increase in clustering intensity reflects the expansion of morphospace that accompanied the diversification, because the expected NND is proportional to the morphologic range. The increases in clustering and in absolute NND hold even if Cambrian genera are treated as equivalent to Ordovician species. [Morphometrics; spatial analysis; trilobites; diversification; computer simulation; taxon-free analysis; early Paleozoic.] Morphology provides the fundamental information upon which evolutionary analysis of the fossil record is based, but macroevolutionary questions are often discussed primarily in taxonomic terms (e.g., Valentine, 1969; Yochelson, 1979; Runnegar, 1987). Taxonomy imposes structure on macroevolutionary analysis not only in cases where conclusions are based on taxon counting. For example, it has been observed that suprageneric taxa of trilobites are morphologically more distinct from each other in the Ordovician than in the Cambrian (Whittington, 1966; Foote, 1989b, in press). The validity of this conclusion rests implicitly on the assumptions that forms are accurately assigned to higher taxa and that these higher taxa are comparable entities. If such assumptions are not met, the reliability of macroevolutionary studies based on higher taxa is limited. (In discussing higher taxa in macroevolutionary analysis of the fossil record, one commonly implies a level between that of the phylum and that of the family. By higher taxa of trilobites I mean superfamilies, suborders, and orders. Discussion of the rationale behind the use of these categories can be found elsewhere [Foote, in press], but is not immediately relevant to the present discussion.) One obvious approach to circumventing problems with the use of higher taxa is to improve the taxonomic structure so that higher taxa are increasingly accurately and consistently defined, by whatever criteria one deems relevant. It is clearly desirable to work within an improved taxonomic framework, but inaccuracies and inconsistencies will always remain. More importantly, even an improved taxonomy still imposes structure on macroevolutionary

Theoretical considerations of density-dependent spacing of a mound-building ant ( Formica altipetens)

Nests of the mound-building ant, Formica altipetens (Hymenoptera: Formicidae), exhibit a pattern of density-dependent spacing. This pattern is observed across 12 small sites (0·0625 and 0·16 ha) and one larger site (2 ha), where F. altipetens nest density varies from 0·01–0·10 nest m−2. Nests are clumped on sites where the average density is less than 0·02 nests m−2. Nests are regularly dispersed on all sites where the average nest density is greater than 0·02 nests m−2. Nest spacing is increasingly regular on sites where there are more ant nests. A simple model that includes both clumped dispersal and local competition during nest establishment also yields a density-dependent spacing pattern. The model consists of two basic parameters: the dispersal distance (D) and the nest territory size (T). A parameterization of the model where D = 10 m and T = 2·5 m explains 75·7% of the empirical variance in an index of nest spacing (the index of dispersion, R, from the Clark & Evans nearest neighbor distance analysis). The spatial patterns of F. altipetens differ quite strongly from “null” versions of the model (no competition with either random dispersal or clumped dispersal). Thus, a model that includes both competition and clumped dispersal explains the spatial arrangement of a mound-building ant in both a qualitative and a quantitative sense.