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opencc-by-4.0Oct 2024View details →

Hollows on Mercury: A Comprehensive Analysis of Spatial Patterns and Their Relationship to Craters and Structures

Supporting Material Content   The raw data collected and produced in this paper are shown in the tables provided as supplementary information to the main text of the article. Specifically, the contents of each table are as follows:   1-    Matrix 1 This table shows the Boolean matrix in which all the data collected for each distinctive trait (header descriptions are reported in Table 1 in the main text) for each hollow location are collected. In Matrix 1 and 2, the ID progressive numbering used in Thomas et al., (2014a) have been maintained. When a new location was added to the list we used the same Id number of the closest identified location by Thomas et al., (2014a). For further clarity an univocal new progressive numbering has been assigned to each location. In addition, (i) the coordinates of the centroid of the mapped polygon for each location (latitude and longitude are provided in decimal degrees) and (ii) the automatically extracted minimum, maximum and mean elevations are given for each polygon. 2-    Matrix 2 This table shows the Boolean matrix in which the occurrences of degradation classes and geologic units are collected for all those hollows contained within craters. These data are reported both as single column cumulative data (e.g., for each location, when available, the degradation class code is reported) and as Boolean matrix. When data are not available for the given location the cells have been left empty. Crater diameters are also reported along with elevations related to crater morphologies. 3-    Matrix 3 This table shows the matrix that collects the results of equations 1, 2 (tab P) and 3 (tab I), described in the methods section, for the entire population of hollows. The data herein reported are the machine-readable version of the data reported in Table 2 in the main text. 4-    Matrix 4 This table shows the matrix that collects the results of equations 1, 2 (tab P) and 3 (tab I), described in the methods section, for the population of hollows contained within craters. This dataset also includes the results of the above equations by taking into account parameters such as degradation classes and geological units (names reported in the headers correspond to the ones used in Matrix 2 which are taken from geological mapping literature. The full literature list can be found in the main text in the methods section).   In addition to these tables, we also provided the GIS-ready shapefile containing all the polygons showing the areas where the hollows were observed, the attributes are the same as those included in Matrix 1.

opencc-zeroDec 2017View details →

Data from: Spatial modeling improves understanding patterns of invasive species defoliation by a biocontrol herbivore

Spatial modeling has proven to be useful in understanding the drivers of plant populations in the field of ecology, but has yet to be applied to understanding variation in biocontrol impact. In this study, we employ multi-scale analysis (Moran's Eigenvector Maps) to better understand the variation in tree canopy exposed to defoliation by a biocontrol beetle (Diorhabda spp.). The control of the exotic tree Tamarix in riparian areas has long been a priority for land managers and ecologists in the American southwest. Diorhabda spp. was introduced as a bio-control agent beginning in 2001 and has since become an inseparable part of Tamarix-dominated river systems in the southwest. Between 2013 and 2016 tamarisk dieback was assessed at 79 sites across Grand County, Utah, arguably the epicenter of Diorhabda impact in the U.S. Canopy cover of Tamarix was between 73%-81% at these sites, with the percent that was live cover fluctuating by year with a minimum of 42%. Using a traditional general linear model, we found that readily and commonly measured environmental factors could explain only up to 26% of the variation in Tamarix live canopy each year, including that number of defoliations was correlated with an increase rather than a decrease in percent live canopy, suggesting compensatory growth. Spatial structure alone explained 22-40% of variation. We found fine scale spatial structure at less than 10 km and broad scale spatial structure from 10-30 km. Combining both traditional and novel spatial statistical methods we increased that percentage to 43-63%, depending on year. These results suggest that scientists and land managers must look beyond commonly measured environmental variables to explain non-random biocontrol impact in this system. In particular, this study points to the potential for biotic interactions and variation in flood cycles for further exploration of the identified spatial structure.

opencc-zeroDec 2013View details →

Data from: Do North Atlantic Eels show parallel patterns of spatially varying selection?

Background: The two North Atlantic eel species, the European and the American eel, represent an ideal system in which to study parallel selection patterns due to their sister species status and the presence of ongoing gene flow. A panel of 80 coding-gene SNPs previously analyzed in American eel was used to genotype European eel individuals (glass eels) from 8 sampling locations across the species distribution. We tested for single-generation signatures of spatially varying selection in European eel by searching for elevated genetic differentiation using FST-based outlier tests and by testing for significant associations between allele frequencies and environmental variables. Results: We found signatures of possible selection at a total of 11 coding-gene SNPs. Candidate genes for local selection constituted mainly genes with a major role in metabolism as well as defense genes. Contrary to what has been found for American eel, only 2 SNPs in our study correlated with differences in temperature, which suggests that other explanatory variables may play a role. None of the genes found to be associated with explanatory variables in European eel showed any correlations with environmental factors in the previous study in American eel. Conclusions: The different signatures of selection between species could be due to distinct selective pressures associated with the much longer larval migration for European eel relative to American eel. The lack of parallel selection in North Atlantic eels could also be due to most phenotypic traits being polygenic, thus reducing the likelihood of selection acting on the same genes in both species.

opencc-zeroDec 2011View details →

Data from: Defining spatial and temporal patterns of phylogeographic structure in Madagascar's iguanid lizards (Genus Oplurus)

Understanding the remarkably high species diversity and levels of endemism found among Madagascar's flora and fauna has been the focus of many studies. One hypothesis that has received much attention proposes that Pleistocene climate fluctuations spurred diversification. However, while spatial patterns of distribution and phylogenetic relationships can provide support for biogeographic predictions, temporal estimates of divergence are required to determine the fit of these geospatial patterns to climatic or biogeographic mechanisms. We use multilocus DNA sequence data to test whether divergence times among Malagasy iguanid lizards of the subfamily Oplurinae are compatible with a hypotheses of Quaternary diversification. We estimate the oplurine species tree and associated divergence times under a relaxed clock model. In addition, we examine the phylogeographic structure and population divergence times within two sister-species of Oplurus primarily distributed in the northwest and southwest of Madagascar (O. cuvieri and O. cyclurus, respectively). We find that divergence events among oplurine lineages occurred in the Oligocene and Miocene and are thus far older and incompatible with the hypothesis that recent climate fluctuations are related to current species diversity. However, the timing of intraspecific divergences and spatial patterns of population genetic structure within O. cuvieri and O. cyclurus suggest a role for both intrinsic barriers and recent climate fluctuations at population-level divergences. Integrating information across spatial and temporal scales allows us to identify and better understand the mechanisms generating patterns diversity.

Figure 1 in Coral reef benthic assemblages of a Marine Protected Area in eastern Brazil: effect of reef habitats on the spatial pattern of species

Figure 1. Location of the Marine Park Recife de Fora within Brazil and south Bahia (left) and map of the study area with sampling stations.

Figure 5 in Coral reef benthic assemblages of a Marine Protected Area in eastern Brazil: effect of reef habitats on the spatial pattern of species

Figure 5. Benthic cover of six major organisms/categories based on the SIMPER test along the reef assemblages recorded in the Marine Park Recife de Fora between February 2008 and January 2009. (a) Halophila decipiens; (b) fleshy macroalgae; (c) turf algae; (d) crustose coralline algae; (e) Millepora alcicornis; (f) Siderastrea spp.

Figure 4 in Coral reef benthic assemblages of a Marine Protected Area in eastern Brazil: effect of reef habitats on the spatial pattern of species

Figure 4. Batimetric profile across the Marine Park Recife de Fora, showing changes in per cent cover of major benthic organisms/categories across the reef habitats.

Figure 3 in Coral reef benthic assemblages of a Marine Protected Area in eastern Brazil: effect of reef habitats on the spatial pattern of species

Figure 3. Multidimensional scaling (NMDS) of benthic assemblages (relative cover of different organisms/categories) based on Chord similarities. (A) Samples classified according to sectors; (B) samples classified according to habitat. Habitats: ALG – algal slope, BAC – back reef, CHA – reef channel, FLA – reef flat, FOR – fore reef, PAT – patch reef, TID – tidal pool and UNC – unconsolidated substrate.

Figure 2 in Coral reef benthic assemblages of a Marine Protected Area in eastern Brazil: effect of reef habitats on the spatial pattern of species

Figure 2. Map of the geomorphologic classification of Voronoi polygons in the Marine Park Recife de Fora (adapted from Arantes and Seoane 2017).

FIG. 4 in Spatial and temporal patterns of territorial mate locating behaviour in Hypolimnas bolina (L.) (Lepidoptera: Nymphalidae)

FIG. 4. The relationship between counts of territorial males and the minimum vegetative corridor width in 10 m segments along both transect 1 (solid triangles) and transect 2 (open squares).

FIG. 2 in Spatial and temporal patterns of territorial mate locating behaviour in Hypolimnas bolina (L.) (Lepidoptera: Nymphalidae)

FIG. 2. Diel patterns of territorial male residence along transect 1 (open squares, solid line) and transect 2 (solid squares, dotted line). The error bars represent Ô1 standard error of sample means, and the ®tted lines are weighted least squares approximations calculated by the STATISTICATM computer program. Sample sizes are given above each hourly point.

FIG. 5 in Spatial and temporal patterns of territorial mate locating behaviour in Hypolimnas bolina (L.) (Lepidoptera: Nymphalidae)

FIG. 5. Representation of hypothetical population-level activity curves derived from simple models of the timing of individual behaviour. Curve A (solid line) represents a population of individuals that arrive at 0900 h and stay for 6 h, curve B (dashed line) represents a population of individuals that arrive at 0900 h and stay for varying times, whilst curve C (dotted line) represents a population of males that arrive at various times but each stay for 3 h.

FIG. 3 in Spatial and temporal patterns of territorial mate locating behaviour in Hypolimnas bolina (L.) (Lepidoptera: Nymphalidae)

FIG. 3. Spatial distribution of territorial males along the length of both transects, with the distribution of the larval food plant species C. cyanea (a), I. triloba (b) and S. nodiXora (c) indicated in the bars above each plot. Transect segments that contained outcrops of ¯owering W. trilobata are indicated by arrows (n 579 for all transect segments).

opennotspecifiedDec 2002View details →

FIG. 6 in Foraging ecology of the giant Amazonian ant Dinoponera gigantea (Hymenoptera, Formicidae, Ponerinae): activity schedule, diet and spatial foraging patterns

FIG. 6. Ritualized territorial contest between Dinoponera gigantea foragers from diVerent colonies at the border of their foraging areas. (A) Ants lock their mandibles together, vigorously antennate each other's head, and constantly kick one another with the Žrst pair of legs. (B) As the contest escalates the dominant ant (right) directs the tip of the gaster against the opponent's body. The subordinate ant eventually walks away as she breaks free.

opennotspecifiedDec 2002View details →

FIG. 2 in Foraging ecology of the giant Amazonian ant Dinoponera gigantea (Hymenoptera, Formicidae, Ponerinae): activity schedule, diet and spatial foraging patterns

FIG. 2. Frequency distribution of trip duration relative to diVerent activities performed by workers of Dinoponera gigantea in a Brazilian rainforest site. Although foraging ants may be away from the nest for up to 3 h, successful foragers usually return after 30–60 min of searching. Data are based on continuous 12-h observations at colony Nos 9 and 10, from 6.00 a.m. to 6.00 p.m. Two successful foragers from each colony are not included in the graphs because the duration of their foraging trips could not be recorded.

opencc-zeroSep 2021View details →

Divergent patterns and spatial heterogeneity of soil nutrients in a complex and dynamic savanna landscape

Many grassy ecosystems around the world are experiencing woody encroachment. These woody encroachers often cause nutrient enrichment in the plant-soil environment, potentially facilitating their growth and reproduction. However, studies of encroachment effects on nutrient distributions have been confined to a few major elements (e.g., N, and P) and limited in spatial extent. We analyzed 19 elements in dominant plants and in georeferenced soils across a subtropical savanna landscape experiencing woody encroachment to quantify their spatial patterns and elucidate drivers responsible for these patterns. We found divergent patterns of spatial heterogeneity of these elements in surface soils across this complex landscape. Nutrient accumulation underneath woody canopies and redistribution by woody plants occurred in a subset of elements (i.e., N, P, S, Ca, Cu, and Sr). Though some of these elements are not necessarily growth-limiting, they do occur in higher concentrations in woody compared to herbaceous plants. Distributions of the other elements were closely related to spatial variation in soil pH, clay content, and slope rather than to woody encroachment. Our nuanced spatial sampling approach and analysis reveal significant variation in nutrient distributions in response to woody encroachment, and illustrate the role of landscape patterns in mediating ecosystem processes. These changes in the concentrations and distributions of key essential nutrients broaden our understanding of the biogeochemical consequences of woody encroachment, and provide new insights regarding the significance of long-term vegetation dynamics in dryland ecosystems.

opencc-zeroNov 2022View details →

Data for: Depth and temperature drive patterns of spatial overlap among fish thermal guilds in lakes across Ontario, Canada

Aim: As fishes are ectothermic, their spatial distributions are strongly dependent on the temperature of their environments. In temperate lakes, fishes with different thermal optima can become spatially segregated during summer stratification. This habitat partitioning, or niche complementarity, may play a role in the coexistence of trophically similar species; however, the extent of partitioning is dependent on the resources available within each habitat. Although habitat partitioning of fish thermal guilds has been studied in individual lakes, broad-scale patterns of spatial overlap and segregation are not yet understood. In this study, we explore the patterns and drivers of spatial overlap among thermal guilds (cold-, cool-, and warm-water) at a broad scale. Location: Ontario, Canada. Methods: We explored patterns of spatial overlap among three thermal guilds, estimated from standardized gillnetting, in 438 lakes. We used a multivariate regression tree to identify such patterns, as well as the environmental factors that drive these patterns. Results: We identified five clusters of lakes exhibiting different patterns of spatial overlap among the three thermal guilds. Temperature (growing degree days) and maximum lake depth were strong drivers of the spatial overlap patterns. The proportional abundance of each thermal guild was similar among the clusters but there was some evidence of species turnover within the warm-water guild. Main conclusions: These findings not only provide a better understanding of broad-scale patterns of spatial overlap, but also allow us to predict how spatial overlap, and ultimately species interactions and competition, may change under a warming climate.

opencc-zeroFeb 2023View details →

Dataset from: Functional traits explain both seedling and adult plant spatial patterns in gypsum annual species

1. Ecological processes such as seed dispersal or plant–plant interactions and environmental constraints such as climate or soil heterogeneity are known to influence establishment, and thus the spatial patterns of plant communities and populations. In this study, we hypothesized that key functional traits such as the specific leaf area (SLA), reproductive ratio (reproductive/vegetative biomass), seed mass, and maximum plant height would influence the spatial patterns of individual species in annual, gypsophilous plant communities, and that these effects would be modulated by both the soil surface structure (biocrust) and climate (precipitation) conditions. 2. We mapped the spatial patterns of all plants found in six 1 x 1 m plots (more than 1000 individuals per plot) in both the seedling (autumn) and adult stages (spring) under two biocrust experimental conditions (intact vs disturbed biocrust) during two consecutive years which were contrasted in term of precipitation (dry year and wet year). To assess the spatial patterns of seedlings and adults, we fitted four different spatial point pattern models (i.e., Poisson, inhomogeneous Poisson, Poisson cluster, and inhomogeneous Poisson cluster processes) to each of the 242 populations of the 27 most abundant species that had more than 15 individuals per plot. 3. Most seedling populations exhibited clustered spatial patterns that persisted in the adult stage, which suggests that short-distance dispersal is an adaptive trait for soil specialists such as gypsophilous plants. One-third of the populations fitted an inhomogeneous model best, but the physical structure of the biocrust was not related to them. More importantly, we found a connection between the functional strategies of species and the spatial distribution of plants. In particular, during the dry year, irrespective of the biocrust conditions, species with a high SLA and high Rep/Veg mainly exhibited clustered spatial patterns, whereas low SLA and low Rep/Veg were associated with random distributions. Species with heavy and light seed masses had random and clustered patterns, respectively. In both the dry and wet years, species with lower maximum heights had clustered patterns, whereas taller species exhibited random patterns. In addition, species with heavier seeds and greater maximum heights had the largest cluster sizes. 4. Our results confirm that the spatial patterns of seedlings and adult plants are significantly determined by the functional strategy of each species.

opencc-zeroMay 2023View details →

Data for: Spatial heterogeneity and infection patterns on epidemic transmission disclosed by a combined contact-dependent dynamics and compartmental model

Epidemics, such as COVID-19, have caused significant harm to human society worldwide. A better understanding of epidemic transmission dynamics can contribute to more efficient prevention and control measures. Compartmental models, which assume homogeneous mixing of the population, have been widely used in the study of epidemic transmission dynamics, while agent-based models rely on a network definition for individuals. In this study, we developed a real-scale contact-dependent dynamic (CDD) model and combined it with the traditional susceptible-exposed-infectious-recovered (SEIR) compartment model.