Compact Patches Research Articles

Morphological Characterization of Native Isolates of Hypocreale Fungi Metarhizium rileyi (Farl.) Samson from Maize Fall Armyworm

The Present studies indicates the collection of entomopathogenic fungi from the roving survey in Northeastern region of Karnataka, India to know the diversity of M. rileyi distribution and also its growth pattern. Different morphological parameters used for describing the growth pattern which indicates diversity and uniqueness of M. rileyi i.e., colony colour which was white during initial stage and then during sporulating stage the colour changed into malachite green colour. The conidiophores were in compact patches. Conidia were aseptate, hyaline, round or ovoid in shape and elongate by forming chains. Conidiophores were short, which bears round to ovoid aseptate conidia in different isolates. The conidia size on its ratio found that, the highest size ratio was recorded in UASRBC Mr-20 2.19 then remaining isolates which has shown less than 2.0. The radial growth found only in Mr-20 and Mr-22nd Isolates, colony diameter ranged from 0.3 to 2.23 cm, concentric rings of colonies found in all the isolates except Mr-19 and Mr-20th isolates. The colony surface layer was white cottony growth to pale yellow color was found in all the isolates, the colony pigmentation in most of the isolates was light brown colored pigmentation. The growth appearance was irregular patchy growth was observed in most of the isolates. Among six different isolates the highest width was recorded in isolate UASRBC Mr-20 (6.46) followed by UASRBC Mr-22 (5.73) which was significantly superior than remaining isolates. The highest colony diameter was recorded in UASRBC Mr-18 (19 mm).

Compact vs. Linear: Effects of Forest Structure, Patch Shape and Landscape Configuration on Black Alder Macromoth Communities

Landscape configuration and forest structure assume an increasing importance as determinants of animal communities. This paper focused on nocturnal Lepidoptera inhabiting alder patches in the Sila National Park, Italy. According to their shapes, patches were divided into linear and compact ones to disentangle the roles of forest structure and landscape configuration in determining the composition of nocturnal Lepidopteran communities at different observation scales. We used the Mann–Whitney test for medians and Shannon diversity, equitability, Fisher’s alpha, and nestedness to test differences among moth communities. We found that compact patches inhabited richer and more abundant communities. The abundance-based Correspondence Analysis showed moth communities clustered according to woodlot shape, except a compact woodlot with a linear-like moth community because it was entirely surrounded by grasslands. Percentage of forested area and abundance and composition of communities were positively correlated at 50 and 200 m buffers, while correlations were absent at smaller and larger buffers. Our results demonstrated that a width of 50 m may not be sufficient to give proper functionality to the wooded area, at least for moths. As a consequence, planning of forest restorations should consider the importance of increasing the structural habitat continuity at larger scales.

Assessment and characterization of sources of error impacting the accuracy of global burned area products

Understanding the sources of error that affect the accuracy of current coarse burned area products is crucial to identifying weaknesses and limitations of burned area (BA) algorithms. In this paper, we propose methods to analyse sources of errors of global BA products, which are applied to assess a widely used product, (FireCCI51), created under the ESA climate change initiative programme. The effect of several variables related to product accuracy are quantified by comparing the FireCCI51 BA product with a large global reference BA dataset for the years 2017–2019. These reference data were obtained from multitemporal analysis of Landsat-8 data. Error maps (commission and omission error layers) were generated for a sample of 316 units (100 km × 100 km) and associations between errors and potential explanatory sources of error were spatially analysed to provide a comprehensive error assessment of the FireCCI51 product. Active fire density, burned severity, burned patch size and land cover class were selected as explanatory variables for omission and commission errors. The results indicated that the largest contribution to the commission errors (70–80%) was related to the pixel size, particularly when pixels are only partially burned. Active fire densities were also associated to error distribution, with higher densities from products derived from the VIIRS sensors versus those generated from MODIS, indicating the potential benefit of the former as an alternative source in upcoming BA algorithms. Burn severity was also associated with error distribution, but this relation varied substantially across biomes. Land cover was also related to errors, with lowest accuracies for croplands with omission error percentages >85%. Fire size and, to a lesser extent, the shape of burned areas also played a crucial role in determining the accuracy of the BA products. BA accuracy increased for larger and more compact burned patches. Although our results suggest that further improvement of global BA products is possible, they also indicate that the ability of coarse spatial resolution BA sensors to meet the accuracy recommendations of the Global Climate Observing System (GCOS) programme is limited.

Forest Habitat Fragmentation in Mountain Protected Areas Using Historical Corona KH-9 and Sentinel-2 Satellite Imagery

Forest habitat fragmentation is one of the global environmental issues of concern as a result of forest management practices and socioeconomic drivers. In this context, a constant evaluation of natural habitat conditions still remains a challenge in order to achieve a general image of the environmental state of a protected area for proper sustainable management. The purpose of our study was to evaluate the evolution of forest habitat in the last 40 years, focusing on Bucegi Natural Park, one of the most frequented protected areas in Romania, as relevant for highly human-impacted areas. Our approach integrates a historical panchromatic Corona KH-9 image from 1977 and present-day Sentinel-2 multispectral data from 2020 in order to calculate a series of spatial metrics that reveal changes in the pattern of the forest habitat and illustrate forest habitat fragmentation density. Object-based oriented analysis with supervised maximum likelihood classification was employed for the production of forest cover fragmentation maps. Ten landscape metrics were adapted to the analysis context, from patch statistics to proximity index. The results show a general growth of the forest surface but also an increase in habitat fragmentation in areas where tourism was developed. Fragmentation indices explain that larger and compact patches feature natural park protected forests after the spruce–fir secondary canopies were grown during the last 4–5 decades. The number of patches decreased to half, and their average size is double that of before. The method can be of extensive use for environmental monitoring in protected areas management and for understanding the environmental history connected to present-day problems that are to be fixed under rising human pressure.

Deep-learning exploration of the acoustic granularity of bat habitats

Many bat species are able to find their way through densely vegetated habitats and select their microhabitats to suit their respective needs. This raises the question as to how granular the natural habitats of bats are when sensed through the echoes triggered by the animals' biosonar pulses. To investigate this question, a portable biomimetic sonar head has been used to collect about 40 000 foliage echoes across a natural forest site on the Virginia Tech campus that was approximately 250 × 140 m2 in size. Each recorded echo was assigned a spatial location that was estimated from the outputs of a concurrently operated GPS receiver. These spatial locations were then used to cluster the echoes into a varying number of compact patches using a k-means clustering algorithm. To determine whether these spatial patches could be determined from the echoes, a convolutional neural network based on the ResNet50 architecture was trained to classify the echoes with respect to their spatial labels. Even based on just a single echo, up to 100 different spatial patches could be distinguished in this way with accuracies greater than 95%. These results demonstrate that bat biosonar can capture sensory information for small-scale navigation in natural forest habitats.

Oasis Landscape Pattern Dynamics in Manas River Watershed Based on Remote Sensing and Spatial Metrics

Constant alterations of oasis landscape pattern, triggered by specific natural and human driving forces, have aroused some heated discussions in the field of regional environmental change research especially in arid areas. In this study, the Normalized Difference Vegetation Index and the Soil Brightness Index have been selected to successfully identify discrete land cover classes derived from a series of Landsat satellite images of Manas River watershed in 1989, 1998, and 2014. FRAGSTATS and principal components analysis were used to recognize independent components of landscape structure. Nine land cover classes combined with ten landscape metrics indicated variations in the composition and configuration of landscape pattern. Results related to historical data were analyzed to identify driving forces, mainly including population growth, agricultural modernization, urbanization, and water resource provision. The results revealed a trend toward less landscape fragmentation, as indicated by a steady decrease in the number of patches as well as an increase in mean patch size and contagion. To be more specific, we found substantial increases in cropland (72.3%) as well as built-up land (43.7%) with larger and more compact patches, while water (64.1%), snow cover (52.0%), and saline–alkali soil (48.5%) dropped sharply. Our findings suggested that population influx and reclamation of saline–alkali soil were two major driving forces critical to those landscape pattern changes.

One-dimensional phosphorus chain and two-dimensional blue phosphorene grown on Au(111) by molecular-beam epitaxy

Single layer (SL) phosphorus (phosphorene) has drawn considerable research attention recently as a two-dimensional (2D) material for application promises. It is a semiconductor showing superior transport and optical properties. Few-layer or SL black phosphorus has been successfully isolated by exfoliation from bulk crystals and extensively studied thereof for its electronic and optical properties. Blue phosphorus (blueP), an allotrope of black phosphorus where atoms are arranged in a more flat atomic configuration, has been recently suggested by theory to exist in the SL form on some substrates. In this work, we report the formation of a blueP-like epilayer on Au(111) by molecular-beam epitaxy. In particular, we uncover by scanning tunneling microscopy (STM) one-dimensional (1D) atomic chains at low coverage, which develop into more compact islands or patches of $(\sqrt{3}\times\sqrt{3})R30^\circ$ structure with increasing coverage before blueP-like islands nucleate and grow. We also note an interesting growth characteristic where the $(\sqrt{3}\times\sqrt{3})R30^\circ$ surface at intermediate coverage tends to phase-separate into locally low-coverage 1D chain and high-coverage blueP-like structures, respectively. This experiment thus not only lends a support of the recently proposed half-layer by half-layer (HLBHL) growth mechanism but also reveals the kinetic details of blueP growth processes.

Urban green effects on land surface temperature caused by surface characteristics: A case study of summer Beijing metropolitan region

The pace of urbanization in China has increased in recent decades. Accordingly, the urbanized area has expanded at a spectacular rate and the urban heat island (UHI) has intensified. Understanding the effects of the landscape pattern on the UHI is crucial for optimizing urban structure, which could mitigate the UHI. This study focused on green cover in an urban area. To investigate how the composition and configuration of urban green patches would affect their temperature in Beijing metropolitan region, China, especially the influence of the configuration of green patches on their cooling effect, the relationships between green surface temperature (GST), normalized difference vegetation index (NDVI), and normalized compactness index (NCI) were investigated by regression analyses, and a method to quantify the cooling effect of greens derived from the urban cool island and green space cool island was proposed. The image from the Landsat Thermal Infrared Sensor was used to estimate GST, and three images from the GF-2 Panchromatic & Multispectral Camera were used to obtain NDVI and calculate NCI. Our results showed that both NDVI and NCI had negative relationships to GST in summer, but only NCI strongly influenced the spatial cooling effect of greens. The further exploration of the influence of NCI on the cooling effect showed the NCI was negatively correlated to the cooling effect, which indicated that, for a given area, more compact green patches reduce the extent of the cooling effect.

A new computer-based approach for fully automated segmentation of knee meniscus from magnetic resonance images

Menisci are tissues that enable mobility and absorb excess loads on the knee. Problems in meniscus can trigger the disorder of osteoarthritis (OA). OA is one of the most common causes of disability, especially among young athlethes and elderly people. Therefore, the early diagnosis and treatment of abnormalities that occur in the meniscus are of significant importance. This study proposes a new computer-based and fully automated approach to support radiologists by: (i) the segmentation of medial menisci, (ii) enabling early diagnosis and treatment, and (iii) reducing the errors caused by MR intra-reader variability. In this study, 88 different MR images provided by the Osteoarthritis Initiative (OAI) are used. The histogram of oriented gradients (HOG) and local binary patterns (LBP) methods are used for feature extraction from these MR images along with the extreme learning machine (ELM) and random forests (RF) methods which are used for model learning (regression). As the first step of the pipeline, the most compact rectangular patches bounding the menisci are located. After this, meniscus boundaries are revealed by the morphological processes. Then, the similarities between these boundaries and the ground truth images are measured and compared with each other. The highest score is acquired with Dice similarity measurement with a success rate of 82%. A successful segmentation is performed on the diseased knee MR images. The proposed approach can be implemented as a decision support system for radiologists, while the segmented menisci can be used in classification of meniscal tear in future studies.

PROPERTIES OF SUPERSONIC EVERSHED DOWNFLOWS

ABSTRACT We study supersonic Evershed downflows in a sunspot penumbra by means of high spatial resolution spectropolarimetric data acquired in the Fe i 617.3 nm line with the CRISP instrument at the Swedish 1 m Solar Telescope. Physical observables, such as Dopplergrams calculated from line bisectors and Stokes V zero-crossing wavelengths, and Stokes V maps in the far red-wing, are used to find regions where supersonic Evershed downflows may exist. We retrieve the line-of-sight velocity and the magnetic field vector in these regions using two-component inversions of the observed Stokes profiles with the help of the SIR code. We follow these regions during their lifetime to study their temporal behavior. Finally, we carry out a statistical analysis of the detected supersonic downflows to characterize their physical properties. Supersonic downflows are contained in compact patches moving outward, which are located in the mid- and outer penumbra. They are observed as bright, roundish structures at the outer end of penumbral filaments that resemble penumbral grains. The patches may undergo fragmentations and mergings during their lifetime; some of them are recurrent. Supersonic downflows are associated with strong and rather vertical magnetic fields with a reversed polarity compared to that of the sunspot. Our results suggest that downflows returning back to the solar surface with supersonic velocities are abruptly stopped in dense deep layers and produce a shock. Consequently, this shock enhances the temperature and is detected as a bright grain in the continuum filtergrams, which could explain the existence of outward-moving grains in the mid- and outer penumbra.

Object-based early monitoring of a grass weed in a grass crop using high resolution UAV imagery

Sorghum halepense (johnsongrass) is a perennial weed with a vegetative reproductive system and one of the most competitive weeds in maize showing a spatial distribution in compact patches. When maize is irrigated, successive weed emergences occur in the early phenological phases of the crop, which require several herbicide applications. Our aim was to provide an accurate tool for an early detection and mapping of johnsongrass patches and delineate the actual surface area requiring a site-specific herbicide treatment based on the weed coverage. This early detection represents a major challenge in actual field scenarios because both species are in the Poaceae family, and show analogous spectral patterns, an extraordinarily similar appearance and a parallel phenological evolution. To solve this, an automatic OBIA (object-based-image-analysis) procedure was developed to be applied on orthomosaicked images using visible (red-green-blue bands) and multispectral (red-green-blue and near infrared bands) cameras collected by an unmanned aerial vehicle (UAV) that flew at altitudes of 30, 60 and 100 m on two maize fields. One of our first phases was the generation of accurate orthomosaicked images of an herbaceous crop such as maize, which presented a repetitive pattern and nearly no invariant parameters to conduct the aerotriangulation. Here, we show that high-quality orthomosaicks were produced from both cameras and that they were able to be the first step for mapping the johnsongrass patches. The most accurate weed maps were obtained using the multispectral camera at an altitude of 30 m in both fields. These maps were then used to design a site-specific weed management program, and we demonstrated that potential herbicide savings ranged from 85 to 96 %. Our results showed that accurate and timely maps of johnsongrass patches in maize can be a key element in achieving site-specific and sustainable herbicide applications for reducing spraying herbicides and costs.

The fetch effect on aeolian sediment transport on a sandy beach: a case study from Magilligan Strand, Northern Ireland

AbstractExperiments were conducted on Magilligan Strand, Northern Ireland, to assess the influence of the fetch effect on aeolian sediment transport. During each experiment surface sediments were uniformly dry and unhindered by vegetation or debris. The leading edge of erodible material was well defined, with the limit of wave up‐rush demarcating the wet–dry boundary; the work was conducted during low tides. A number of electronic and integrating traps were utilised, with two ultrasonic anemometers used to measure wind direction and velocity at 1 Hz. The combination of 1o direction data and trap locations resulted in a range of fetch distances, from 2 to 26 m. Data integrated over 15‐minute intervals (corresponding to the integrating trap data) revealed a distinct trend for all the experiments. An initial rapid increase in the transport rate occurred over a short distance (4–9 m). This maximum transport rate was maintained for a further 5–6 m before a steady decay in the flux followed, as fetch distance increased. A measured reduction in wind speed (6–8%) across the beach suggests a negative feedback mechanism may be responsible for the diminishing transport rate: the saltating grains induce energy dissipation, thus reducing the capability of the wind to maintain transport. For one experiment, the presence of compact sediment patches may also have contributed to the reduction of the transport rate. The decay trend calls into question the utility of the fetch effect as an important parameter in aeolian studies that seek to understand sediment budgets of the foredune‐beach zone. Copyright © 2016 John Wiley & Sons, Ltd.

Self-organized patchiness facilitates survival in a cooperatively growing Bacillus subtilis population.

Ecosystems are highly structured. Organisms are not randomly distributed but can be found in spatial aggregates at many scales, leading to spatial heterogeneity or even regular patterns(1). The widespread occurrence of these aggregates in many different ecosystems suggests that generic factors intrinsic to the populations-such as interactions between the organisms-play a major role in their emergence(1,2). Beyond the emergence of spatial patchiness, its functional consequences remain unclear. Here we show in Bacillus subtilis that cooperative interactions in a spatial environment are sufficient to form self-organized patches. These patches allow for survival even when the microbe density is too low to sustain growth in a well-mixed environment. Decreasing cell mobility leads to more compact patches that enhance this survival advantage but also reduce the overall growth. Our results highlight that even populations lacking specific group-forming mechanisms can nonetheless form spatial patterns that allow for group survival in challenging environments.

Detecting the tensor-to-scalar ratio with the pure pseudospectrum reconstruction ofB-mode

In this work we employ the pure-pseudo formalism devised to minimise the effects of the leakage on the variance of power spectrum estimates and discuss the limits on the tensor-to-scalar ratio, $r$, that could be realistically set by current and forthcoming measurements of the $B$-mode angular power spectrum. We compare those with the results obtained using other approaches: na\"{i}ve mode-counting, minimum-variance quadratic estimators, and re-visit the question of optimizing the sky coverage of small-scale, suborbital experiments in order to maximize the statistical significance of the detection of $r$. We show that the optimized sky coverage is largely insensitive to the adopted approach at least for reasonably compact sky patches. We find, however, that the mode-counting overestimates the detection significance by a factor $\sim1.17$ as compared to the lossless maximum variance approach and by a factor $\sim1.25$ as compared to the lossy pure pseudo-spectrum estimator. In a second time, we consider more realistic experimental configurations. With a pure pseudospectrum reconstruction of $B$-modes and considering only statistical uncertainties, we find that a detection of $r\sim0.11$, $r\sim0.0051$ and $r\sim0.0026$ at 99$\%$ of confidence level is within the reach of current sub-orbital experiments, future arrays of ground-based telescopes and a satellite mission, respectively. This means that an array of telescopes could be sufficient to discriminate between large- and small-field models of inflation, even if the $E$-to-$B$ leakage is consistently included but accounted for in the analysis. However, a satellite mission will be required to distinguish between different small-field models depending on the number of e-folds.

Landscape persistence and stakeholder perspectives: The case of Romania's Carpathians

The traditional use of land for food, fuel and wood created cultural landscapes, which are threatened across Europe. The factors which contributed to their endangerment need to be identified to achieve effective preservation of such landscapes. The aim of our study was to identify landscapes with historical persistence in a GIS-based comparative analysis of historical and contemporary maps and the most prominent causes of the past landscape changes, based on stakeholders' perspective. We considered a case study in Romania's Carpathians. Three major land cover types were extracted from maps dating from 1912, 1980 and 2009: built-up, pastures and forests. The historical persistence of all land cover types was poor (<20%) and profound changes were quantitatively confirmed. Large, compact patches of unchanged forests were located in the neighbourhood of a national park. The persistent pastures were situated close to human settlements, and their preservation can be related to local traditional agro-silvo-pastoral management. Although the built-up area has increased over time, the corresponding surfaces are small and consist of scattered patches located around historical monuments. Semi-structured interviews were conducted to investigate stakeholders' perspective. Using cluster analysis five prominent causes of past landscape changes are identified: 'increasing tourism', 'land tenure and social changes', 'land-use intensification', 'post-communist transition', and 'foreign investments'. We join the results of the GIS analysis with those from stakeholders' perspective to gain more insights into the landscape changes. This research offers important information that could be used for the further planning of these valuable cultural landscapes in order to avoid potential conflicts and degradation.

Effects of human‐modified landscapes on taxonomic, functional and phylogenetic dimensions of bat biodiversity

AbstractAimTo identify characteristics of a human‐modified landscape that promote taxonomic (TD), functional (FD) and phylogenetic (PD) dimensions of bat biodiversity.LocationCaribbean lowlands of northeastern Costa Rica.MethodsDuring the dry and wet seasons, we quantified TD (Simpson's diversity), as well as FD and PD (Rao's quadratic entropy) of phyllostomid bat assemblages at 15 sites that represented a forest loss and fragmentation gradient. FD was estimated separately for each of seven functional components that reflect particular niche axes (e.g. diet, foraging strategy) and for all functional components combined (FDall). PD was based on relatedness of species derived from a supertree. We identified the best explanatory landscape characteristics of each dimension using hierarchical partitioning.ResultsLandscape effects were dimension and season specific. During the dry season, TD and PD increased with increasing proportions of pasture or size of forest patches, whereas FDall decreased with increasing size of forest patches. During the wet season, TD increased with increasing forest patch size, whereas FDall and PD increased with increasing compactness of forest patches and decreasing proximity. Decomposition of FD into separate functional components revealed different landscape effects on ecological aspects of assemblages.Main conclusionsOne dimension of biodiversity was not a good surrogate for another. Rather, decomposition of biodiversity into different dimensions and functional components facilitated identification of the aspects of assemblages that are most affected by forest conversion and fragmentation. Areas with intermediate amounts of forest and pasture during the dry season harboured highest diversity from taxonomic, functional and phylogenetic perspectives. During the wet season, areas with large, compact forest patches promoted the dimensions of biodiversity. Placement of areas with even amounts of forest and pasture adjacent to large, compact forest patches (e.g. reserves) may maintain high biodiversity of bats and the ecosystem functions that they provide throughout the year.

1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)-rich domain formation in binary phospholipid vesicle membranes: two-dimensional nucleation and growth.

Decades of study have probed phase transitions in model phospholipid bilayers and vesicles, especially in the context of the equilibrium phase diagram. Critical to the response of vesicles to environmental triggers, to the ultimate domain morphology, and to the approach to equilibrium (or not), we present here a study of domain formation in vesicles, focusing on a mechanism by which the cooling rate, tension, and composition affect the first appearance (nucleation) and subsequent growth of solid membrane domains. Employing a popular mixed membrane model based on DOPC and DPPC (1,2-dioleoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, respectively), we examined phase separation in giant two-component vesicles that were cooled from the one-phase fluid (Lα) region of the phase diagram into a region of fluid (Lα)-solid coexistence. At moderate and low membrane tensions, cooling produced solid DPPC-rich domains appearing as compact patches or irregular hexagons and likely with a Pβ' (ripple) arrangement. (The compact solid domains in this study differed distinctly from striped domains in vesicles of the same composition, in terms of molecular organization and conditions of first appearance during cooling.) The amounts of these solid domains were shown to adhere to the lever arm rule for a tie line on the phase diagram, with a solid composition near 95 mol % DPPC. The nucleation of the compact solid domains occurred in a short period, followed by rapid addition of ordered molecules to the nucleated domains, excluding tracer dye. The two-dimensional nucleation density of these compact solid domains (in the range of 10(-2)-10(-1) μm(-2)) was found to increase with the cooling rate (equivalent to the quench depth) with a greater than linear dependence. The 2-D nucleation density was also seen to decrease with membrane tension, presumably because membrane tension increases the line tension around a domain that opposes nucleation. A sigmoidal dependence of the nucleation density on the DPPC concentration was also found. With cooling rates in excess of ∼1 °C/min, solid domains persisted down to room temperature, likely passing from a preferred equilibrium to a local equilibrium with continued cooling. As a result of the persistence of the originally nucleated domains and the conservation of DPPC in the membrane, we observed an increasingly greater number of smaller domains with increased cooling rates. The domains in these vesicles were compact or hexagonal-shaped in contrast to flower-shaped dendritic domains in the same membrane system in a supported membrane configuration.

Alameda Song Sparrow Abundance Related to Salt Marsh Vegetation Patch Size and Shape Metrics Quantified from Remote Sensing Imagery

Understanding the characteristics of high-quality avian habitat is critical for guiding salt marsh man- agement and restoration. Existing insights into salt marsh avian habitat are often based on the com- position of marsh vegetation, e.g., individual plant species cover. This study investigated whether the spatial configuration of marsh surface cover (e.g., patch number, density, size, shape complexity and compactness, degree of dissection of the landscape, variation and repetition of cover type, and the vari- ance within these metrics) is a useful, additional indi- cator of avian habitat quality for the Alameda Song Sparrow (Melospiza melodia pusillula), a non-migra- tory California Species of Special Concern endemic to southern San Francisco Bay. M. m. pusillula density during the breeding seasons of 2002 through 2005 was estimated at 82 observation points in 10 marsh sites within the bird's geographic range. The mean bird density index (overall mean: 5.61 birds detected per hectare of marsh) was not significantly different among marshes of different ages. We mapped the vegetation zones, open water, and upland areas with- in each marsh site using high resolution aerial pho- tographs and automated classification analysis. We quantified the configuration of surface cover around each bird observation point by 31 metrics. Bird den- sity index was best modeled by a multiple linear regression containing positive relationships with the metrics Mean Core Area Index and Patch Core Area Coefficient of Variation (R 2 = 0.210, p < 0.0001). Qualitatively, this model suggested that M. m. pusil- lula abundance during the breeding season was greatest in marsh areas with compact patches that spanned a variety of patch sizes from moderate-to- large, uninterrupted by other cover. We conclude that configuration-based vegetation pattern analysis could usefully complement more customary composition- based habitat assessments to aid wetland habitat research, management, and restoration.

The biology of Mercurialis perennis L. polycormones

The developmental cycle of &lt;em&gt;Mercurialis perennis&lt;/em&gt; L. polycormones lasts about 6 years. Under natural conditions polycormones arise by way of vegetative propagation. Their development and growth depend on the age, size and developmental state of the part of the plant from which the new individual arises. Development of the polycormone is most intensive in the first three years. During that time the young individuals increase their number of above-ground and underground shoots according to geometrical progression. A certain stabilization in growth and spread was observed in the 4th and 5th year of life. At that time the polycormones are of spherical or oval shape and their structure is mono- and polycentric. Their surface area is 0.51-2.0 m&lt;sup&gt;2&lt;/sup&gt; and the number of above-ground shoots amounts to 80-200. In the following years the intensity of regeneration decreases. Polycormones developing in garden culture reach their senile phase in the 3rd and 4th year of life, whereas in natural conditions in the 5th and 6th year. Then gradual dying of the oldest parts of the polycormone starts its division into several independent units. The rapid increase of the area occupied by the newly arising individuals leads to obliteration of the boundaries between them. The development of the aggregation-field distribution specific for this species is preceded by random and aggregation-random distribution of the polycormones in the &lt;em&gt;Tilio-Carpinetum&lt;/em&gt; herb layer. It is evaluated that compact one-species patches of &lt;em&gt;Mercurialis parennis&lt;/em&gt; L. form in forest communities in about 10 years.

Observations of region-specific fish behavior using long- and short-range broadband (1.5—6 + kHz) active acoustic systems

Two broadband active acoustic systems, in concert with traditional narrowband systems and nets, were used to study distributions of fish in three regions within the Gulf of Maine. The long-range multi-beam broadband system detected fish out to 15 km range and the downward-looking short-range broadband system detected fish throughout the water column close behind the ship. The multi-year (2007–2011) study revealed distinct spatial patterns of fish and corresponding echo statistics in each region—diffusely distributed, sparsely distributed compact patches, and long (continuous) shoals. The broadband capabilities of the sonar systems (each spanning 1.5—6 + kHz) uniquely allow observations of resonance phenomena of the local swimbladder-bearing fish. The observed resonances were consistent with the fish species, sizes, and depths that were concurrently sampled in each area from a second research vessel. Spectral peak analysis also interestingly revealed the presence of distinct modes, which may be useful indicators of mixed-species and/or mixed-sized (e.g., juvenile and adult) assemblages of fish. [Work supported by Office of Naval Research.]