scholarly journals A test of the hypothesis that the spatial scale of effect of the landscape context on an ecological response increases with increasing time scale over which the response is regulated

2017 ◽  
Author(s):  
Andrew Moraga
Keyword(s):  
Spatial Scale ◽  
Time Scale ◽  
Landscape Context ◽  
Ecological Response ◽  
Scale Of Effect

scholarly journals The interplay of spatial scale and landscape transformation moderates the abundance and intraspecific variation in the ecomorphological traits of a phyllostomid bat

2021 ◽  
Author(s):  
Andres F Ramirez-Mejia ◽  
Nicolas Urbina-Cardona ◽  
Francisco Sanchez
Keyword(s):  
Spatial Scale ◽  
Spatial Scales ◽  
Species Abundance ◽  
Environmental Filters ◽  
Wild Fauna ◽  
Landscape Transformation ◽  
Biological Responses ◽  
Scale Of Effect ◽  
Urban Rural ◽  
Phenotype Selection

Land-use intensification imposes selective pressures that systematically change the frequency of wild population phenotypes. Growing evidence is biased towards the comparison of populations from discrete categories of land uses, ignoring the role of landscape emerging properties on the phenotype selection of wild fauna. Across the largest urban-rural gradient of the Colombian Orinoquia, we measured ecomorphological traits of 216 individuals of the Flat-faced Fruit-eating Bat Artibeus planirostris, to evaluate the scale of effect at which landscape transformation better predicts changes in phenotype and abundance of an urban-tolerant species. Forest percentage at 1.25 km was the main predictor affecting abundance, wing aspect ratio, and body mass of this phyllostomid; but the direction of the effect differed between abundance and ecomorphological traits. Although landscape factors explained changes in the forearm length at all spatial scales, the effect was sex-dependent and the most important predictor was forest percentage at 0.5 km. Our results indicate that landscape elements and spatial scale interact to shape ecomorphological traits and the abundance of A. planirostris. Interestingly, the scale of effect was congruent among all biological responses. A pattern that likely arises since species' abundance can reflect the variation on phenotype under different environmental filters across landscape scenarios.

scholarly journals Localized fast flow disturbance observed in the plasma sheet and in the ionosphere

2005 ◽  
Vol 23 (2) ◽  
pp. 553-566 ◽  
Author(s):  
R. Nakamura ◽  
O. Amm ◽  
H. Laakso ◽  
N. C. Draper ◽  
M. Lester ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Current Sheet ◽  
Plasma Sheet ◽  
Time Scale ◽  
Ionospheric Disturbance ◽  
Flow Shear ◽  
Current Location ◽  
Field Aligned Current ◽  
Temporal And Spatial ◽  
Fast Flow

Abstract. An isolated plasma sheet flow burst took place at 22:02 UT, 1 September 2002, when the Cluster footpoint was located within the area covered by the Magnetometers-Ionospheric Radars-All-sky Cameras Large Experiment (MIRACLE). The event was associated with a clear but weak ionospheric disturbance and took place during a steady southward IMF interval, about 1h preceding a major substorm onset. Multipoint observations, both in space and from the ground, allow us to discuss the temporal and spatial scale of the disturbance both in the magnetosphere and ionosphere. Based on measurements from four Cluster spacecraft it is inferred that Cluster observed the dusk side part of a localized flow channel in the plasma sheet with a flow shear at the front, suggesting a field-aligned current out from the ionosphere. In the ionosphere the equivalent current pattern and possible field-aligned current location show a pattern similar to the auroral streamers previously obtained during an active period, except for its spatial scale and amplitude. It is inferred that the footpoint of Cluster was located in the region of an upward field-aligned current, consistent with the magnetospheric observations. The entire disturbance in the ionosphere lasted about 10min, consistent with the time scale of the current sheet disturbance in the magnetosphere. The plasma sheet bulk flow, on the other hand, had a time scale of about 2min, corresponding to the time scale of an equatorward excursion of the enhanced electrojet. These observations confirm that localized enhanced convection in the magnetosphere and associated changes in the current sheet structure produce a signature with consistent temporal and spatial scale at the conjugate ionosphere.

scholarly journals At what scales does aggregated dispersal lead to coexistence?

2016 ◽  
Author(s):  
Eric J Pedersen ◽  
Frederic Guichard
Keyword(s):  
Spatial Scale ◽  
Time Scale ◽  
Spatial Scales ◽  
Stochastic Simulations ◽  
Ecological Conditions ◽  
Competitive Outcomes

Aggregation during dispersal from source to settlement sites can allow persistence of weak competitors, by creating conditions where stronger competitors are more likely to interact with conspecifics than with less competitive heterospecifics. However, different aggregation mechanisms across scales can lead to very different patterns of settlement. Little is known about what ecological conditions are required for this mechanism to work effectively. We derive a metacommunity approximation of aggregated dispersal that shows how three different scales interact to determine competitive outcomes: the spatial scale of aggregation, the spatial scale of interactions between individuals, and the time-scale of arrival rates of aggregations. We use stochastic simulations and a novel metacommunity approximation to show that an inferior competitor can invade only when the superior competitor is aggregated over short spatial scales, and aggregations of new settlers are small and rare.

The scale of effect of landscape context varies with the species’ response variable measured

2019 ◽  
Vol 34 (4) ◽  
pp. 703-715 ◽  
Author(s):  
Andrew D. Moraga ◽  
Amanda E. Martin ◽  
Lenore Fahrig
Keyword(s):  
Landscape Context ◽  
Response Variable ◽  
Species Response ◽  
Scale Of Effect

All-Atom Molecular Dynamics Simulation of Submicron Thickness EHL Oil Film

2007 ◽  
Author(s):  
Hitoshi Washizu ◽  
Shuzo Sanda ◽  
Shi-Aki Hyodo ◽  
Toshihide Ohmori ◽  
Noriaki Nishino ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Spatial Scale ◽  
Time Scale ◽  
External Pressure ◽  
Dynamics Simulation ◽  
Lubricating Oil ◽  
Large Spatial Scale ◽  
Oil Film ◽  
Scale Thickness ◽  
Long Time

All-atom molecular dynamics simulations of an elastohydrodynamic lubricating oil film have been performed to study the effect of the oil film thickness (large spatial scale; thickness: 430 nm, MD time: 25 ns) and the effect of pressure (long time scale; thickness: 10 nm, MD time: 50 ns, external pressure: 0.1 to 8.0 GPa). Fluid layers of n-hexane are confined between two solid Fe plates by a constant normal force. Traction simulations are performed by applying a relative sliding motion to the Fe plates. In a long spatial scale simulation, the mean traction coefficient was 0.03, which is comparable to the experimental value of 0.02. In a long time scale simulation, a transition of the traction behavior is observed around 0.5 GPa to 1.0 GPa which corresponds to a change from the viscoelastic region to the plastic-elastic region which have been experimentally observed. This phase transition is related to a suppressed fluctuation of the molecular motion.

scholarly journals Bee responses to landscape composition on coupled and decoupled multiscale approaches

2021 ◽  
Author(s):  
Lazaro Carneiro ◽  
Milton Cezar Ribeiro ◽  
Willian Moura de Aguiar ◽  
Camila de Fátima Priante ◽  
Wilson Frantine-Silva ◽  
...  
Keyword(s):  
Forest Cover ◽  
Linear Models ◽  
Landscape Heterogeneity ◽  
Spatial Scales ◽  
Landscape Composition ◽  
Landscape Context ◽  
Multiscale Approach ◽  
Ecological Processes ◽  
Positive Effects ◽  
Scale Of Effect

Abstract ContextMultiscale approaches are essential for understanding ecological processes and detecting the scale of effect. However, nested multiscale approaches retain the effect of the landscape attributes from the smaller spatial scales into the larger ones. Thus, decoupling local vs. regional scales can reveal detailed ecological responses to landscape context, but this multiscale approach is poorly explored. ObjectivesWe evaluated the scale of effect of the forest cover (%) and landscape heterogeneity on Euglossini bees combining coupled and decoupled multiscale approaches. MethodsThe Euglossini males were sampled in forest patches from 15 landscapes within the Atlantic Forest, southeast Brazil. For simplicity, we defined that the coupled approaches represented the local scales and decoupled approaches the regional scales. We decoupled the scales by cutting out the smaller scales inserted into larger ones. We estimated the relationship of the bee community attributes with forest cover (%) and landscape heterogeneity in local and regional scales using Generalized Linear Models. ResultsWe found positive effects of landscape heterogeneity on species richness for regional scales. Forest cover and landscape heterogeneity in local scales showed positive effects on the euglossine abundances. The scale of effect for euglossine richness was higher than species abundances. ConclusionsCombining coupled and decoupled multiscale approaches showed adequate capture of the scale of effect of the landscape composition on bee communities. Therefore, it is of paramount importance to measure the influence of the landscape context on biodiversity. Maintaining landscapes with larger forest cover and spatial heterogeneity is essential to keep euglossine species requirements.

Dynamics at the demographic time scale

2012 ◽  
Author(s):  
Odo Diekmann ◽  
Hans Heesterbeek ◽  
Tom Britton
Keyword(s):  
Population Growth ◽  
Spatial Scale ◽  
Time Scale ◽  
Host Population ◽  
Temporal And Spatial ◽  
Two Parameters ◽  
Infective Agent

This chapter focuses on the influence of the demography on the persistence of an infective agent, and vice versa on the influence of the agent on host population growth and persistence. When new “fuel” is provided through the replacement of immune individuals by newborn susceptibles, the infective agent may strike again at a later time or even persist and become endemic. Whether we observe repeated outbreaks or relatively small fluctuations around a steady endemic level depends on the temporal and spatial scale that we, as investigators of the system, choose to monitor and/or to model. The chapter also suggests that two parameters, rather than just one, are needed to distinguish between a single outbreak (which may reoccur much later by reintroduction of the agent from the outside) and the endemic situation.

scholarly journals Urban arthropods respond variably to changes in landscape context and spatial scale

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Monika H. Egerer ◽  
Courtney Arel ◽  
Michelle D. Otoshi ◽  
Robyn D. Quistberg ◽  
Peter Bichier ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Landscape Context

The interplay of spatial scale and landscape transformation modulates the abundance and intraspecific variation in the ecomorphological traits of a phyllostomid bat

2021 ◽  
pp. 1-8
Author(s):  
Andrés F. Ramírez-Mejía ◽  
J. Nicolás Urbina-Cardona ◽  
Francisco Sánchez
Keyword(s):  
Spatial Scale ◽  
Spatial Scales ◽  
Species Abundance ◽  
Environmental Filters ◽  
Wild Fauna ◽  
Landscape Transformation ◽  
Scale Of Effect ◽  
Negative Effect ◽  
Urban Rural ◽  
Phenotype Selection

Abstract Land use intensification imposes selective pressures that systematically change the frequency of wild population phenotypes. Growing evidence is biased towards the comparison of populations from discrete categories of land uses, ignoring the role of landscape emerging properties on the phenotype selection of wild fauna. Across the largest urban–rural gradient of the Colombian Orinoquia, we measured ecomorphological traits of 216 individuals of the flat-faced fruit-eating bat Artibeus planirostris. We did this to evaluate the scale of effect at which landscape transformation better predicts changes in phenotype and abundance of an urban-tolerant species. Forest percentage at 1.25 km was the main predictor affecting negatively bat abundance and positively its wing aspect ratio and body mass. Landscape variables affected forearm length at all spatial scales, this effect appeared to be sex-dependent, and the most important predictor, forest percentage at 0.5 km, had a negative effect on this trait. Our results indicate that landscape elements and spatial scale interact to shape ecomorphological traits and the abundance of A. planirostris. Interestingly, the scale of effect coincided at 1.25 km among all biological responses, suggesting that species’ abundance can be linked to the variation on phenotype under different environmental filters across landscape scenarios.

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