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The Atlantic surfclam Spisula solidissima supports one of the largest fisheries on the US northeast coast. Using ∼30 yr of data from surfclam stock surveys, variance-to-mean ratios (VtMRs) were calculated both temporally and spatially for a range of surfclam size classes to determine the degree of patchiness. The VtMR declined from the 1980s to present in all regions (offshore Delmarva, New Jersey, Long Island, Southern New England, Georges Bank); however, VtMR rose with increasing clam size. Taylor’s power law (TPL) analysis corroborated the VtMR; the surfclam is highly patchy across its range. The surfclam’s proclivity for a patchy distribution varied regionally. Regions supporting the bulk of the stock were characterized by significantly higher degrees of patchiness and exhibited a higher exponent for the TPL. A species distribution function model corroborated findings of declining patchiness over time, supporting the hypothesis that warming of Mid-Atlantic continental shelf bottom waters is both driving the surfclam into new habitat and extirpating it from nearshore and southern areas. Size-dependent and temporal trends in VtMRs and temporal relative stability in TPL suggest that range expansion is conduced by regional settlement of larvae, followed by biased mortality in suboptimal habitats. This biased mortality ultimately re-establishes the increased patchiness characteristic of larger animals but also predisposes the species to a rapid range shift. Declining VtMRs over time may be a symptom of range expansion along the leading range boundary that has increased the proportion of newly occupied habitat without mature patch characteristics while, at the same time, range recession has removed the older mature patches along the range’s trailing edge.

Spatially explicit consideration of species distribution can significantly add to our understanding of species coexistence. In this paper, we evaluated the relative importance of habitat heterogeneity and other clustering processes (e.g., dispersal limitation, collectively called the non‐habitat clustering process) in explaining the spatial distribution patterns of 341 tree species in three stem‐mapped 25–50 ha plots of tropical, subtropical, and temperate forests. Their relative importance was estimated by a method that can take one mechanism into account when estimating the effects of the other mechanism and vice versa. Our results demonstrated that habitat heterogeneity was less important in explaining the observed species patterns than other clustering processes in plots with flat topography but was more important in one of the three plots that had a complex topography. Meanwhile, both types of clustering mechanisms (habitat or non‐habitat) were pervasive among species at the 50‐ha scale across the studied plots. Our analyses also revealed considerable variation among species in the relative importance of the two types of mechanism within each plot and showed that this species‐level variation can be partially explained by differences in dispersal mode and growth form of species in a highly heterogeneous environment. Our findings provide new perspectives on the formation of species clustering. One important finding is that a significant species–habitat association does not necessarily mean that the habitat heterogeneity has a decisive influence on species distribution. The second insight is that the large species‐level variation in the relative importance of the two types of clustering mechanisms should not be ignored. Non‐habitat clustering processes can play an important role on species distribution.

The effects of plants on soil vary greatly between plant species and in mixed plant communities this can lead to spatial variation in plant‐soil feedback (PSF) effects. Such spatial effects are thought to influence plant species coexistence, but the empirical evidence for this hypothesis is limited. Here, we investigate how spatial heterogeneity in PSFs influences plant growth and competition. The experiment was carried out with high and low nutrient soils to examine how these effects depend on soil fertility. We collected soil from field plots planted for three years with monocultures of Anthoxanthum odoratum and Centaurea jacea and tested the performance of the two species in a greenhouse experiment in heterogeneous soils consisting of patches of “own” and “foreign” soils and in soils where the “own” and “foreign” soils were mixed homogeneously. In the test phase, plants were grown in monocultures and in 1:1 mixtures in live or sterilized soils. Overall, A. odoratum in monocultures produced less aboveground biomass in heterogeneous soils than in homogeneous soils. Centaurea jacea produced less belowground biomass in live heterogeneous soils than in live homogeneous soils, but there was no difference between sterile heterogeneous and homogeneous soils. The belowground biomass per patch varied more in pots with live heterogeneous soils than in pots with live homogeneous soils for both plant species, but there was no difference between pots with sterile heterogeneous and homogeneous soils. In pots with plant mixtures, the difference in aboveground biomass between the two competing species tended to be smaller in heterogeneous than in homogeneous soils. In pots with heterogeneous soils, both plant species grown in mixtures produced more aboveground biomass in “foreign” soil patches than in “own” soil patches. The responses of plants to heterogeneous PSFs were not different between low and high nutrient soils. Our results show that spatially heterogeneous PSFs can influence plant performance and competition via reducing the growth inequality between the two competing species by allowing selective growth in foreign soil patches, independent of initial soil nutrient availability. Such effect may slow down exclusion processes and thus promote the coexistence of competing species at the local scale in mixed plant communities. A plain language summary is available for this article. Plain Language Summary

The aim of this study was to use unmanned aerial vehicles (UAVs) as a supplement to satellite remote sensing to accurately assess benthic seaweed biomass in intertidal zones, in order to improve inversion accuracy results and investigate the spatial distribution patterns of seaweed. By adopting non-multicollinearity vegetation indices (feature sets) from PlanetScope and Sentinel-2, and using benthic seaweed biomass inverted from multispectral UAV imagery as the label set for satellite pixel biomass values, machine learning methods (Gradient boosting decision tree, GBDT) can effectively improve the accuracy of biomass estimation results for Ulva pertusa and Sargassum thunbergii species (Ulva pertusa, RSentinel22 = 0.74, RPlanetScope2 = 0.8; Sargassum thunbergii, RSentinel22 = 0.88, RPlanetScope2 = 0.69). The average biomasses of Ulva pertusa and Sargassum thunbergii in the intertidal zone of Gouqi Island are 456.84 g/m2 and 2606.60 g/m2, respectively, and the total resources are 3.5 × 108 g and 1.4 × 109 g, respectively. In addition, based on the hyperspectral data, it was revealed that a major source of error is the patchy distribution of seaweed.

The issue of searching and collecting targets with patchy distribution in an unknown environment is a challenging task for multiple or swarm robots because the targets are unevenly dispersed in space, which makes the traditional solutions based on the idea of path planning and full spatial coverage very inefficient and time consuming. In this paper, by employing a novel framework of spatial-density-field-based interactions, a collective searching and collecting algorithm for heterogeneous swarm robots is proposed to solve the challenging issue in a self-organized manner. In our robotic system, two types of swarm robots, i.e., the searching robots and the collecting robots, are included. To start with, the searching robots conduct an environment exploration by means of formation movement with Levy flights; when the targets are detected by the searching robots, they spontaneously form a ring-shaped envelope to estimate the spatial distribution of targets. Then, a single robot is selected from the group to enter the patch and locates at the patch’s center to act as a guiding beacon. Subsequently, the collecting robots are recruited by the guiding beacon to gather the patch targets; they first form a ring-shaped envelope around the target patch and then push the scattered targets inward by using a spiral shrinking strategy; in this way, all targets eventually are stacked near the center of the target patch. With the cooperation of the searching robots and the collecting robots, our heterogeneous robotic system can operate autonomously as a coordinated group to complete the task of collecting targets in an unknown environment. Numerical simulations and real swarm robot experiments (up to 20 robots are used) show that the proposed algorithm is feasible and effective, and it can be extended to search and collect different types of targets with patchy distribution.

PREMISE OF THE STUDY: Species with habitat specificity show restricted distribution, and the limited dispersal provides opportunity for long-term isolation. Aquatic Podostemaceae grow on rocks in river rapids, which are extreme habitats for angiosperms. To infer the diversification process of the podostemad species in such specific habitats, we investigated environmental factors shaping their distribution and the relationship between their distribution and genetic structure. METHODS: We used Hydrobryum japonicum and Cladopus doianus, which have contrasting distributions (i.e., narrower and wider, respectively) in southern Kyushu, Japan. Environmental factors contributing to their distribution were estimated by ecological niche modeling. Using polymorphisms in chloroplast DNA, we performed population genetic analyses of 13 H. japonicum populations occurring in nearby river basins and eight C. doianus populations in distant rivers. KEY RESULTS: Estimation of distribution probability showed great contributions of geology and temperature to the distribution of these populations, suggesting that the species grow on volcanic rocks in relatively warm areas. Genetic analyses revealed higher interpopulational genetic diversity than intrapopulational diversity and strong differentiation between rivers in both species. No correlation between genetic and geographic distances was detected among the C. doianus populations, in contrast to the significant correlation observed in the H. japonicum populations. CONCLUSIONS: The high-level genetic differentiations among populations of the two species may result from their limited dispersal. Their restricted habitats, which are primarily characterized by volcanic rocks in rapids and lower temperatures in winter, may enhance isolation among populations in distant rivers.

Zooplankton generally distributes patchily. Distributional patchiness could be adaptive to survival and reproduction, especially for large branchiopods that live in temporary pools with variable aquatic environments. We focused on spatial utilization by three sympatric large branchiopods in a subtropical temporary pool (Siangtian Pond, northern Taiwan): Branchinella kugenumaensis (Ishikawa, 1895) (Anostraca), Eulimnadia braueriana Ishikawa, 1895 (Spinicaudata), and Lynceus biformis (Ishikawa, 1895) (Laevicaudata). Sampling along transects were conducted across four hydroperiods. The number of adults for each species was recorded to describe patchiness, edge aggregation, and hotspots of peak density. We found that the three species showed patchy distribution, which could reflect resource heterogeneity. Only B. kugenumaensis consistently aggregated toward the edge, and we hypothesize that this distributional tendency correlates with mating behavior. Hotspots of L. biformis were concentrated in the deepest locations, possibly due to late maturation and limited utilization area available for adults. In contrast, the early-maturing E. braueriana was scattered widely throughout the basin without an obvious pattern. Patchy distribution could be a common phenomenon for large branchiopods in temporary pools, whereas species-specific distribution patterns depend on multiple factors.

Philippine False Geckos (genus Pseudogekko) are secretive, delicate, slender-bodied, arboreal members of an obligate forest specialist clade that is substantially more species diverse than previously assumed. Over the last century, few species were added to this Philippine endemic genus. During the last decade, however, revisionary studies have resulted in the recognition of six new species. Several of these appear to be rare, have restricted geographic ranges, or exhibit patchy, fragmented areas of occurrence. In this study we report on the discovery of a second Luzon Island species in the P. brevipes complex, a clade in which members typically have diminutive bodies. Although the new species is readily diagnosed from all congeners, we estimated its systematic affinities with a phylogenetic analysis of DNA sequence data and confirm that it is nested within the P. brevipes clade. The new species constitutes an exception to the general appearance of other members of the P. brevipes complex, in that it has a relatively heavy-bodied, robust stature, separating it phenotypically from all members of the group. Our new species constitutes the second Luzon lineage in this group of rainforest species (considered previously to be restricted to the Negros-Panay and Mindanao Pleistocene aggregate island complexes [PAICs] in the central and southern landmasses of the archipelago). Given the lack of available biodiversity information for the major remaining forests of the Bicol Peninsula, which necessarily come from targeted faunal surveys, the new species' conservation status cannot yet be assessed. In light of the highly fragmented nature of forested habitats of southern Luzon, we suspect the new species might be vulnerable to extinction as a result of habitat loss.

Microbial community composition is essential for aquatic ecosystem functions and has been explored across diverse environments and various spatial scales. However, documented patterns are often based on samples from spatially/geographically separated locations or sites. Here, we define sampling volume as spatial scale and examine (by Illumina 16S rRNA sequencing) microbial community composition over a scale of 1 mL to 10 L in an acid mine drainage. β-Diversity analysis revealed that all samples grouped very tightly according to spatial scales and variations between every two scales were significant. Notably, mean β-diversity within each group was negatively correlated with spatial scales, indicating patchy microbial distribution. Partition of β-diversity further revealed that it was the relative abundances of some microbial taxa that largely changed among spatial scales. Phylogenetic analysis showed that microbial lineages were not randomly distributed, but displayed a tendency of more phylogenetically clustering at smaller spatial scales. Thus, we documented fine-scale spatial patterns in microbial community composition within a continuous aquatic environment, which may have practical implications for adequate sampling of aquatic systems in future studies.

Dispersal is a major and critical process in population biology that has been particularly challenging to study. Animals can have major roles in seed dispersal even in species that do not appear specifically adapted to animal-aided dispersal. This can occur by two processes: direct movement of diaspores by animals and modification of landscape characteristics by animals in ways that greatly influence dispersal. We exploited the production of large, persistent dispersal structures (seed heads, henceforth) by Erodiophyllum elderi (Asteraceae), a daisy from arid Australia, to further understand secondary dispersal. Seed head dispersal on and off animal tracks in eight E. elderi patches was monitored for 9.5 months by periodically recording the location of marked seed heads. Sites were located inside a reserve that excludes sheep but not kangaroos, and in a nearby area with both kangaroos and sheep. The distance moved and likelihood of seed head movement was higher in areas with sheep, and especially along animal tracks. There was clear evidence that seed heads were channeled down animal tracks during large rainfall events. Seed head dispersal away from patches occurred to a limited extent via their physical contact with sheep and potentially via wind dispersal. Thus, the advantages of this study system allowed us to demonstrate the two postulated effects of herbivores on dispersal via direct movement of seed heads, and two distinct indirect effects through landscape modification by herbivores from the creation of animal tracks and the denudation of vegetation.