Fine Scale (fine + scale)

Distribution by Scientific Domains


Selected Abstracts


Effects of Rapid Broadband Trills on Responses to Song Overlapping in Nightingales

ETHOLOGY, Issue 4 2010
Philipp Sprau
In communication, animals often use complex signals with different traits carrying different information. In the song of some songbirds, both trills and song overlapping signal arousal or the readiness to escalate a contest in male-male interactions, yet they also differ inherently from each other. Song overlapping is restricted to interactions and has a clear directive function as the songs are timed specifically to the songs of a counterpart. Trills, however, can be used without opponents actively singing and do not have such a directional character unless when combined with directed traits. This difference raises the question whether trills can enhance the agonistic function of song overlapping when being used simultaneously. Here, we exposed male nightingales (Luscinia megarhynchos) prior to pairing to overlapping playback treatments differing in the presence or absence of rapid broadband trills. Males responded differently to the two playback treatments suggesting that song overlapping and rapid broadband trills have some synergistic effects. Consequently, the separate or simultaneous use of trills and of song overlapping may allow males to adjust information encoded in their singing on a fine scale. Furthermore, males that remained unpaired throughout the breeding season responded differently to the playbacks than did subsequently paired males, emphasizing the implications of differences in territory defence behaviour on males subsequent pairing success. [source]


The contributions of topoclimate and land cover to species distributions and abundance: fine-resolution tests for a mountain butterfly fauna

GLOBAL ECOLOGY, Issue 2 2010
Javier Gutiérrez Illán
ABSTRACT Aim, Models relating species distributions to climate or habitat are widely used to predict the effects of global change on biodiversity. Most such approaches assume that climate governs coarse-scale species ranges, whereas habitat limits fine-scale distributions. We tested the influence of topoclimate and land cover on butterfly distributions and abundance in a mountain range, where climate may vary as markedly at a fine scale as land cover. Location, Sierra de Guadarrama (Spain, southern Europe) Methods, We sampled the butterfly fauna of 180 locations (89 in 2004, 91 in 2005) in a 10,800 km2 region, and derived generalized linear models (GLMs) for species occurrence and abundance based on topoclimatic (elevation and insolation) or habitat (land cover, geology and hydrology) variables sampled at 100-m resolution using GIS. Models for each year were tested against independent data from the alternate year, using the area under the receiver operating characteristic curve (AUC) (distribution) or Spearman's rank correlation coefficient (rs) (abundance). Results, In independent model tests, 74% of occurrence models achieved AUCs of > 0.7, and 85% of abundance models were significantly related to observed abundance. Topoclimatic models outperformed models based purely on land cover in 72% of occurrence models and 66% of abundance models. Including both types of variables often explained most variation in model calibration, but did not significantly improve model cross-validation relative to topoclimatic models. Hierarchical partitioning analysis confirmed the overriding effect of topoclimatic factors on species distributions, with the exception of several species for which the importance of land cover was confirmed. Main conclusions, Topoclimatic factors may dominate fine-resolution species distributions in mountain ranges where climate conditions vary markedly over short distances and large areas of natural habitat remain. Climate change is likely to be a key driver of species distributions in such systems and could have important effects on biodiversity. However, continued habitat protection may be vital to facilitate range shifts in response to climate change. [source]


Resistant pityriasis lichenoides et varioliformis acuta in a 3-year-old boy

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2010
Successful treatment with methotrexate
Pityriasis lichenoides et varioliformis acuta (PLEVA) represents the acute clinical subtype of pityriasis lichenoides (PL) and its occurrence is relatively common during childhood. Diagnosis and treatment may sometimes pose certain difficulties. We present the recalcitrant case of a 3-year-old boy with an asymptomatic polymorphic eruption consisting of multiple, scattered, 0.5 cm, round to ovoid, erythematous papules covered in places with a fine scale, vesicles and superficial erosions with thick hemorrhagic crusts. The correlation of the clinical features with the lesional histopathology favored the diagnosis of PLEVA. No first-line treatment scheme succeeded in controlling the eruption of new lesions. The only therapeutic approach that eventually managed to cease the disease evolution was the combination of prednisolone and methotrexate. [source]


ENVIRONMENTAL FACTORS INFLUENCING THE DISTRIBUTION OF SOUTHERN RIGHT WHALES (EUBALAENA AUSTRALIS) ON THE SOUTH COAST OF SOUTH AFRICA II: WITHIN BAY DISTRIBUTION

MARINE MAMMAL SCIENCE, Issue 3 2004
Simon H. Elwen
Abstract Environmental factors are thought to strongly influence the distribution and predictability of the coastal distribution of southern right whales (Eubalaena australis) off South Africa. Preferred habitat had generally shallow sloping sedimentary floors and was characteristically protected from open ocean swell and prevalent seasonal winds. This study investigated whether habitat choices at smaller scales (within bays) were similar. Fine scale distribution patterns (GPS) from three years' surveys (1997, 1999, 2000) were analyzed separately within the three main concentration areas St Sebastian Bay, De Hoop, and Walker Bay (containing ,73% of cow-calf pairs and ,49% of unaccompanied adults in the whole survey region). Whale density at this scale of within particular bays did not correlate well with predicted variables, but Chi-squared analysis strongly supported results at broader scales, in all bays. Post-hoc"choice" tests between similar areas differing in only one variable revealed that cow-calves preferred (presumed) sandy substrates and especially protection from swell. The strength and predictability of preferences shown at fine scale (where individual movement and weather variability could have great influence) provide strong support for findings at larger scales and emphasize the importance of environmental factors in the habitat choice of wintering right whales. [source]


Microstructures of metal grains in ordinary chondrites: Implications for their thermal histories

METEORITICS & PLANETARY SCIENCE, Issue 3 2000
Hugues LEROUX
Three ordinary chondrites, Saint Séverin (LL6), Agen (H5), and Tsarev (L6) were selected because they display contrasting microstructures, which reflects different thermal histories. In Saint Séverin, the microstructure of the Ni-rich metal grains is due to slow cooling. It consists of a two-phase assemblage with a honeycomb structure resulting from spinodal decomposition similar to the cloudy zone of iron meteorites. Microanalyses show that the Ni-rich phase is tetrataenite (Ni = 47 wt%) and the Ni-poor phase, with a composition of ,25% Ni, is either martensite or taenite, these two occurring adjacent to each other. The observation that the Ni-poor phase is partly fcc resolves the disagreement between previous transmission electron microscopy (TEM) and Mössbauer studies on iron meteorites and ordinary chondrite metal. The Ni content of the honeycomb phase is much higher than in mesosiderites, confirming that mesosiderites cooled much more slowly. The high-Ni tetrataenite rim in contact with the cloudy zone displays high-Ni compositional variability on a very fine scale, which suggests that the corresponding area was destabilized and partially decomposed at low temperature. Both Agen and Tsarev display evidence of reheating and subsequent fast cooling obviously related to shock events. Their metallic particles mostly consist of martensite, the microstructure of which depends on local Ni content. Microstructures are controlled by both the temperature at which martensite forms and that at which it possibly decomposes. In high-Ni zones (>15 wt%), martensitic transformation started at low temperature (<300 °C). Because no further recovery occurred, these zones contain a high density of lattice defects. In low-Ni zones (<15 wt%), martensite grains formed at higher temperature and their lattice defects recovered. These martensite grains present a lath texture with numerous tiny precipitates of Ni-rich taenite (Ni = 50 wt%) at lath boundaries. Nickel composition profiles across precipitate-matrix interfaces show that the growth of these precipitates was controlled by preferential diffusion of Ni along lattice defects. The cooling rates deduced from Ni concentration profiles and precipitate sizes are within the range 1,10 °C/year for Tsarev and 10,100 °C/year for Agen. [source]


Recurrent nuclear DNA introgression accompanies chloroplast DNA exchange between two eucalypt species

MOLECULAR ECOLOGY, Issue 7 2010
G. E. MCKINNON
Abstract Numerous studies within plant genera have found geographically structured sharing of chloroplast (cp) DNA among sympatric species, consistent with introgressive hybridization. Current research is aimed at understanding the extent, direction and significance of nuclear (nr) DNA exchange that accompanies putative cpDNA exchange. Eucalyptus is a complex tree genus for which cpDNA sharing has been established between multiple species. Prior phylogeographic analysis has indicated cpDNA introgression into the widespread forest species Eucalyptus globulus from its rare congener E. cordata. In this study, we use AFLP markers to characterize corresponding nrDNA introgression, on both a broad and fine spatial scale. Using 388 samples we examine (i) the fine-scale spatial structure of cp and nrDNA introgression from E. cordata into E. globulus at a site in natural forest and (ii) broad-scale patterns of AFLP marker introgression at six additional mixed populations. We show that while E. globulus and E. cordata retain strongly differentiated nuclear gene pools overall, leakage of nrDNA occurs at mixed populations, with some AFLP markers being transferred to E. globulus recurrently at different sites. On the fine scale, different AFLP fragments show varying distances of introgression into E. globulus, while introgression of cpDNA is extensive. The frequency of E. cordata markers in E. globulus is correlated with spatial proximity to E. cordata, but departs from expectations based on AFLP marker frequency in E. cordata, indicating that selection may be governing the persistence of introgressed fragments in E. globulus. [source]


Multi-scale modelling of two-phase,two-component processes in heterogeneous porous media

NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 9 2006
J. Niessner
Abstract This work deals with flow and transport phenomena in porous media, which occur on different space and time scales. Additionally, the porous medium itself is heterogeneous where the heterogeneities occur on all spatial scales. We consider a large domain with randomly distributed heterogeneities where complex two-phase,two-component processes are relevant only in a small (local) subdomain. This subdomain needs fine resolution as the complex processes are governed by small-scale effects. For a comprehensive fine-scale model taking into account two-phase,two-component processes as well as heterogeneities in the whole (global) model domain, data collection is expensive and computational time is high. Therefore, we developed a multi-scale concept where on the one hand, the global flow field influences the local two-phase,two-component processes on the fine scale. On the other hand, a coarse-scale saturation equation is solved where the effects of the fine-scale two-phase,two-component processes in the subdomain are captured by source/sink terms and the effects of fine-scale heterogeneities by a macrodispersion term. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Extension of ideal free resource use to breeding populations and metapopulations

OIKOS, Issue 1 2000
C. Patrick Doncaster
The concept of an ideal and free use of limiting resources is commonly invoked in behavioural ecology as a null model for predicting the distribution of foraging consumers across heterogeneous habitat. In its original conception, however, its predictions were applied to the longer timescales of habitat selection by breeding birds. Here I present a general model of ideal free resource use, which encompasses classical deterministic models for the dynamics in continuous time of feeding aggregations, breeding populations and metapopulations. I illustrate its key predictions using the consumer functional response given by Holling's disc equation. The predictions are all consistent with classical population dynamics, but at least two of them are not usually recognised as pertaining across all scales. At the fine scale of feeding aggregations, the steady state of an equal intake for all ideal free consumers may be intrinsically unstable, if patches are efficiently exploited by individuals with a non-negligible handling time of resources. At coarser scales, classical models of population and metapopulation dynamics assume exploitation of a homogeneous environment, yet they can yield testable predictions for heterogeneous environments too under the assumption of ideal free resource use. [source]


Amplified fragment length polymorphism among Rhynchosporium secalis isolates collected from a single barley field in Syria

ANNALS OF APPLIED BIOLOGY, Issue 3 2005
A KIROS-MELES
Summary AFLP markers were used to measure the amount and distribution of genetic variation among Rhynchosporium secalis isolates on a microgeographical scale in Syria. Forty isolates hierarchically sampled from a single barley field were assayed for AFLP variation using primer combinations not previously tested in populations of the pathogen from Syria. In contrast to a previous study, which showed high clonality within field populations of R. secalis in Syria, the present study revealed a much higher level of genetic diversity, stressing the important roles that sampling strategies and the choice of primers/primer combinations play in the evaluation of genetic variation in R. secalis populations at a microgeographical scale. A high level of genetic variation was found to occur on a fine scale throughout the pathogen population examined, with 40 different haplotypes being identified among the 40 isolates sampled. Data were consistent with the hypothesis that the primary inoculum originated from a genetically diverse founding population, which may have consisted of ascospores of an as yet undescribed teleomorph and/or asexual spores of a highly mutable local population. [source]


The interrelationship between productivity, plant species richness and livestock diet: a question of scale?

APPLIED VEGETATION SCIENCE, Issue 2 2007
Karin Süss
Wisskirchen & Haeupler (1998) Abstract Question: What relationship exists between productivity, plant species richness and livestock diet? Are the results dependent on scale? Location: A sheep-grazed Koelerio-Corynephoretea sandy habitat of the northern upper Rhine (Germany) as a low productivity model system. Methods: The investigation was carried out for three years at a fine scale (2 m2) and for two years at a broad scale (79 m2). Productivity was measured by means of weighed above-ground phytomass for fine scale and colour-infrared (CIR) aerial photographs of the same system for fine and broad scales. For both scales, total numbers of vascular plant species and numbers of endangered vascular plant species were extracted from current vegetation relevés. Additionally, we obtained data on livestock diet (grazed phytomass, crude protein content). Results: Statistical analyses show an influence of the year on all variables; relationships between variables are not significant in every year. Species richness and number of endangered species are negatively related to productivity at fine scale while crude protein content and grazed phytomass are positively related to productivity. At the broad scale the diversity-productivity relationship shows a ,hump' with highest species numbers in middle pioneer stages; numbers of endangered species are highest in all pioneer stages. Conclusions: We found a strong impact of scale and year on the diversity-productivity relationship. It is inappropriate to analyse only small plots (2 m2), and it is necessary to study different years. This vegetation complex is dependent on grazing impact; thus there is an inversely proportional relationship between nature conservation value (high diversity) and livestock nutrition. [source]


Interactive effects of distance and matrix on the movements of a peatland dragonfly

ECOGRAPHY, Issue 5 2009
Krista S. Chin
We conducted a mark,release,recapture survey of a peatland dragonfly (Leucorrhinia hudsonica) in each of two years (2002; 2003) in a harvested forest landscape in western Newfoundland, Canada. The odds of an individual male moving between peatlands was influenced by both the distance between peatlands and the type of intervening habitat (the matrix). Specifically, at meso scales (>700,m) there was a positive effect of the amount of cut matrix between peatlands on the odds of moving, but at fine scales (<700,m) there was the opposite effect; proportionally fewer individuals moved between peatlands. The odds of moving out of a peatland decreased as the surface area of water in the peatland increased. Multi-state mark,recapture models showed that the daily probability of a male moving between any two peatlands was 1.9% in 2002 and 6.9% in 2003 (n=1527 and 1280 marked individuals). The results suggest that additional empirical studies that directly measure patterns of movement with respect to landscape structure at multiple spatial scales in other taxa and situations are needed in order to uncover other possible non-linear changes in behavior. [source]


Using patch studies to link mesoscale patterns of feeding and growth in larval fish to environmental variability

FISHERIES OCEANOGRAPHY, Issue 4 2002
John F. Dower
We present results from a series of three patch studies designed to examine links between environmental variability and mesoscale patterns of feeding and growth of larval radiated shanny (Ulvaria subbifurcata). We examine the effects of variability in temperature, turbulence and prey concentration on both the mean (i.e. population level) and the variance (i.e. individual level) of larval feeding and growth rates among the three bays. Although both gut fullness and growth rates differ significantly between bays, our results show only weak environmental influences. When larvae are pooled across bays (i.e. treated as independent observations), environmental factors generally explain <4% of the variability in gut fullness. When treated as daily mean residuals, however, temperature accounts for 41% of the variability in mean gut fullness, while both temperature and prey concentration also explain significant portions of the variance in gut fullness (38 and 43%, respectively). Between-bay differences in larval growth rates are consistent with patterns of temperature variation but not with patterns of prey availability. Studies relying on tracking a single patch of larvae typically suffer from having too few observations to detect significant relationships between feeding or growth and environmental variables. By following three patches we collected a larger number of observations. However, as we encountered only a limited range of environmental conditions it remains difficult to adequately assess the role of environmental factors. In part, this problem stems from the inability of fisheries oceanographers to track the recent environmental history of individual larvae on the same fine scales currently employed to collect biological data (e.g. guts and otoliths) on individuals. [source]


Predicting abundance from occupancy: a test for an aggregated insect assemblage

JOURNAL OF ANIMAL ECOLOGY, Issue 3 2003
M. Warren
Summary 1The ubiquitous, positive abundance-occupancy relationship is of potential value to conservation and pest management because of the possibility of using it to predict species abundance from occupancy measures. 2He & Gaston (2000a) developed a model, and a parameterization method, for the prediction of abundance from occupancy based on the negative binomial distribution. There are to date few empirical tests of either the estimation method or model. Here we conduct such a test in a field-based mesocosm experiment using a Drosophilidae assemblage associated with decaying fruit. 3With individual (and groups of) fruit as minimum mapping units, abundance estimates derived using the parameterization method of the He-Gaston model differed significantly from measured values, and were least accurate for the most abundant species. 4Substitution of k -values corrected for species density in the model did not improve abundance predictions significantly. However, substitution of k -values calculated directly from the negative binomial distribution yielded highly accurate abundance predictions. 5Although the distribution of fly species did not deviate significantly from the negative binomial distribution, and the finest possible minimum mapping units were used (individual fruit), the parameterization method in the He-Gaston model consistently underestimated the abundance of species in the assemblage because individuals were very highly aggregated within fruit. 6Because of its potential importance, this model and parameterization method require further exploration at fine scales, commonly represented by individual habitat units, for highly aggregated species. The incorporation of spatially explicit information may provide a means of improving abundance predictions in this regard. [source]


Microsatellite variation and fine-scale population structure in the wood frog (Rana sylvatica)

MOLECULAR ECOLOGY, Issue 5 2001
Robert A. Newman
Abstract We investigated genetic population structure in wood frogs (Rana sylvatica) from a series of Prairie Pothole wetlands in the northern Great Plains. Amphibians are often thought to exist in demographic metapopulations, which require some movement between populations, yet genetic studies have revealed strong subdivision among populations, even at relatively fine scales (several km). Wood frogs are highly philopatric and studies of dispersal suggest that they may exhibit subdivision on a scale of , 1,2 km. We used microsatellites to examine population structure among 11 breeding assemblages separated by as little as 50 m up to , 5.5 km, plus one population separated from the others by 20 km. We found evidence for differentiation at the largest distances we examined and among a few neighbouring ponds, but most populations were strikingly similar in allele frequencies, suggesting high gene flow among all but the most distant populations. We hypothesize that the few significant differences among neighbouring populations at the finest scale may be a transient effect of extinction,recolonization founder events, driven by periodic drying of wetlands in this hydrologically dynamic landscape. [source]


Quantifying habitat structure: surface convolution and living space for species in complex environments

OIKOS, Issue 12 2008
D. M. Warfe
Habitat complexity is often used to explain the distribution of species in environments, yet the ability to predict outcomes of structural differences between habitats remains elusive. This stems from the difficulty and lack of consistency in measuring and quantifying habitat structure, making comparison between different habitats and systems problematic. For any measure of habitat structure to be useful it needs to be applicable to a range of habitats and have relevance to their associated fauna. We measured three differently-shaped macrophyte analogues with nine indices of habitat structure to determine which would best distinguish between their shape and relate to the abundance and rarefied species richness of their associated macroinvertebrate assemblages. These indices included the physical, whole-plant attributes of surface area (SA) and plant volume (PV), the interstitial space attributes of average space size and frequency (ISI), average refuge space from predation (Sp/Pr), and total refuge space (FFV), and the degree of surface convolution at a range of scales (i.e. the fractal dimension at four spatial scales: 7.5×, 5×, 2.5× and 1× magnification). We found a high degree of inter-correlation between the structural indices such that they could be organised into two suites: one group describing interstitial space and surface convolution at coarse scales, the other describing whole-plant attributes and surface convolution at fine scales. Two of these indices fell into both suites: the average refuge space from predation (Sp/Pr) and the fractal dimension at 5× magnification. These two measures were also strongly related to macroinvertebrate abundance and rarefied species richness, which points to their usefulness in quantifying habitat structure and illustrates that habitat structure depends not just on shape, but on the space associated with shape. [source]


Local and regional spatial distribution of an eruptive and a latent herbivore insect species

AUSTRAL ECOLOGY, Issue 2 2003
Katia T. Ribeiro
Abstract In this work, we investigated the spatial distribution of two sessile insect herbivores over the entire range of their host plant, Coccoloba cereifera, a sclerophyllous shrub endemic to Serra do Cipó, Brazil. The two insects have very distinct life histories and dispersal behaviours and we hypothesized that their classification into behavioural syndromes could be used to predict their spatial distribution patterns. Abgrallaspis cyanophylli (Homoptera) is an armoured scale insect that fits well into the eruptive syndrome. Stenapion aff. contrarium (Coleoptera) is a petiole borer with wide search capabilities, which fits into the latent syndrome. We expected that Abgrallaspis would follow the host plant aggregation pattern whereas Stenapion would be distributed more uniformly through the region and be less affected by host aggregation. We counted the number of attacked and non-attacked ramets within two perpendicular belt transects as well as within a 20 m × 20 m quadrat placed over a dense shrub aggregation. Local quadrat covariance methods were used to estimate the spatial pattern of each insect. At fine scales, we found Stenapion evenly distributed over the host plant and Abgrallaspis with a significantly aggregated pattern. This finding is in accordance with our hypothesis. At larger scales, however, this pattern was lost and the results were largely variable. We conclude that the classification of insects into behavioural syndromes may be useful to predict distribution patterns at fine scales. At larger scales, however, history and chance events may be more important. [source]