scholarly journals Scale-Dependent Browsing Patterns on Canada Yew (Taxus canadensis) by White-Tailed Deer (Odocoileus virginianus)

2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Steve K. Windels ◽  
David J. Flaspohler
Keyword(s):  
Odocoileus Virginianus ◽  
Spatial Scales ◽  
Stable States ◽  
Factors Affecting ◽  
Multiple Spatial Scales ◽  
Taxus Canadensis ◽  
Deer Density ◽  
Two Factors ◽  
The Usa ◽  
Canada Yew

Canada yew (Taxus canadensis) is a clonal shrub that forms discrete patches and was formerly an important component of forest understories in much of northeastern North America. Following Euro-American settlement, Canada yew has been extirpated or reduced in abundance throughout much of its former range, particularly in the USA; winter browsing by white-tailed deer (Odocoileus virginianus) has been implicated as responsible for much of its decline. Little is known about the factors affecting deer browsing intensity on Canada yew. We examined factors related to browsing intensity on Canada yew across three spatial scales in 29 forest stands in Michigan, USA. Browsing intensity on stems was related principally to two factors acting simultaneously across multiple spatial scales. Browsing intensity was negatively related to amount of Canada yew at the scale of the forest stand and negatively related to distance from the edge of Canada yew patches, effectively creating refugia from browsing. The browsing patterns we observed suggest that yew exists in two alternate stable states: (1) as loose aggregations of small stems or (2) large, dense patches of large stems. The implications of changes in deer density or snow cover to the probability of local persistence of Canada yew are discussed.

scholarly journals Spatial Structure among the Geometric Earthworks of western Amazonia (Acre, Brazil)

2019 ◽  
Author(s):  
Philip Riris
Keyword(s):  
Analytical Approach ◽  
Amazon Basin ◽  
Spatial Scales ◽  
Relative Importance ◽  
Factors Affecting ◽  
Multiple Spatial Scales ◽  
Archaeological Models ◽  
And Function ◽  
Open Question ◽  
Territorial Integration

Fieldwork and desk-based research in the western Amazon basin has led to an explosive growth in the state of knowledge surrounding the pre-Columbian archaeology of this region. Previously thought to be a sparsely occupied environment, archaeologists have recorded hundreds of geometric earthworks between the Purús and Acre rivers in recent years, spurring renewed interest in understanding the distribution, age, and function of these structures. A challenge has been to identify possible relationships between sites and to place them in their broader landscape setting. The precise spatial scale, relative importance of different factors, and strength of any relationships that contributed to shaping their distributions remain an open question. This paper develops and applies an explicitly spatial framework to address this problem, drawing on a rich body of recent research in Acre state (Brazil) and advanced point process modelling. The analytical approach, which is fully documented and reproducible with the accompanying code, infers the factors affecting earthwork distribution at multiple spatial scales. This enables the first robust predictions of territorial integration in the region, which is discussed context of extant archaeological models. The findings support the interpretation that non-stratified societies occupied likely Acre during the late pre-Columbian period.

Predicting probability of occurrence and factors affecting distribution and abundance of three Ozark endemic crayfish species at multiple spatial scales

2014 ◽  
Vol 59 (11) ◽  
pp. 2374-2389 ◽  
Author(s):  
Matthew S. Nolen ◽  
Daniel D. Magoulick ◽  
Robert J. DiStefano ◽  
Emily M. Imhoff ◽  
Brian K. Wagner
Keyword(s):  
Spatial Scales ◽  
Factors Affecting ◽  
Probability Of Occurrence ◽  
Multiple Spatial Scales ◽  
Crayfish Species

Inhibition of coral settlement at multiple spatial scales by a pervasive algal competitor

2019 ◽  
Vol 612 ◽  
pp. 29-42 ◽  
Author(s):  
NR Evensen ◽  
C Doropoulos ◽  
KM Morrow ◽  
CA Motti ◽  
PJ Mumby
Keyword(s):  
Spatial Scales ◽  
Coral Settlement ◽  
Multiple Spatial Scales

scholarly journals Responses of Vertebrate Wildlife to Oil and Natural Gas Development: Patterns and Frontiers

2021 ◽  
Author(s):  
A. D. Chalfoun
Keyword(s):  
Natural Gas ◽  
Anthropogenic Activities ◽  
Spatial Scales ◽  
Habitat Type ◽  
Population Level ◽  
Low Frequencies ◽  
Natural Gas Development ◽  
The Usa ◽  
Oil And Natural Gas

Abstract Purpose of Review Anthropogenic activities can lead to the loss, fragmentation, and alteration of wildlife habitats. I reviewed the recent literature (2014–2019) focused on the responses of avian, mammalian, and herpetofaunal species to oil and natural gas development, a widespread and still-expanding land use worldwide. My primary goals were to identify any generalities in species’ responses to development and summarize remaining gaps in knowledge. To do so, I evaluated the directionality of a wide variety of responses in relation to taxon, location, development type, development metric, habitat type, and spatiotemporal aspects. Recent Findings Studies (n = 70) were restricted to the USA and Canada, and taxonomically biased towards birds and mammals. Longer studies, but not those incorporating multiple spatial scales, were more likely to detect significant responses. Negative responses of all types were present in relatively low frequencies across all taxa, locations, development types, and development metrics but were context-dependent. The directionality of responses by the same species often varied across studies or development metrics. Summary The state of knowledge about wildlife responses to oil and natural gas development has developed considerably, though many biases and gaps remain. Studies outside of North America and that focus on herpetofauna are lacking. Tests of mechanistic hypotheses for effects, long-term studies, assessment of response thresholds, and experimental designs that isolate the effects of different stimuli associated with development, remain critical. Moreover, tests of the efficacy of habitat mitigation efforts have been rare. Finally, investigations of the demographic effects of development across the full annual cycle were absent for non-game species and are critical for the estimation of population-level effects.

Assessment of clogging in constructed wetlands by saturated hydraulic conductivity measurements

2019 ◽  
Vol 79 (2) ◽  
pp. 314-322 ◽  
Author(s):  
F. Licciardello ◽  
R. Aiello ◽  
V. Alagna ◽  
M. Iovino ◽  
D. Ventura ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Constructed Wetlands ◽  
Spatial Scales ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Test Method ◽  
Conductivity Measurements ◽  
Multiple Spatial Scales ◽  
Ks Values

Abstract This study aims at defining a methodology to evaluate Ks reductions of gravel material constituting constructed wetland (CW) bed matrices. Several schemes and equations for the Lefranc's test were compared by using different gravel sizes and at multiple spatial scales. The falling-head test method was implemented by using two steel permeameters: one impervious (IMP) and one pervious (P) on one side. At laboratory scale, mean K values for a small size gravel (8–15 × 10−2 m) measured by the IMP and the P permeameters were equal to 19,466 m/d and 30,662 m/d, respectively. Mean Ks values for a big size gravel (10–25 × 10−2 m) measured by the IMP and the P permeameters were equal to 12,135 m/d and 20,866 m/d, respectively. Comparison of Ks values obtained by the two permeameters at laboratory scale as well as a sensitivity analysis and a calibration, lead to the modification of the standpipe equation, to evaluate also the temporal variation of the horizontal Ks. In particular, both permeameters allow the evaluation of the Ks decreasing after 4 years-operation and 1–1.5 years' operation of the plants at full scale (filled with the small size gravel) and at pilot scale (filled with the big size gravel), respectively.

scholarly journals FORMULATION OF THE HEAT CONDUCTION EQUATION FOR HETEROGENEOUS MEDIA WITH MULTIPLE SPATIAL SCALES USING REITERATED HOMOGENIZATION

2016 ◽  
Vol 15 (1) ◽  
pp. 96
Author(s):  
E. Iglesias-Rodríguez ◽  
M. E. Cruz ◽  
J. Bravo-Castillero ◽  
R. Guinovart-Díaz ◽  
R. Rodríguez-Ramos ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Small Parameter ◽  
Heat Conduction Equation ◽  
Heterogeneous Media ◽  
Spatial Scales ◽  
Conduction Equation ◽  
Small Scale ◽  
Multiple Spatial Scales ◽  
Effective Coefficients ◽  
Reiterated Homogenization

Heterogeneous media with multiple spatial scales are finding increased importance in engineering. An example might be a large scale, otherwise homogeneous medium filled with dispersed small-scale particles that form aggregate structures at an intermediate scale. The objective in this paper is to formulate the strong-form Fourier heat conduction equation for such media using the method of reiterated homogenization. The phases are assumed to have a perfect thermal contact at the interface. The ratio of two successive length scales of the medium is a constant small parameter ε. The method is an up-scaling procedure that writes the temperature field as an asymptotic multiple-scale expansion in powers of the small parameter ε . The technique leads to two pairs of local and homogenized equations, linked by effective coefficients. In this manner the medium behavior at the smallest scales is seen to affect the macroscale behavior, which is the main interest in engineering. To facilitate the physical understanding of the formulation, an analytical solution is obtained for the heat conduction equation in a functionally graded material (FGM). The approach presented here may serve as a basis for future efforts to numerically compute effective properties of heterogeneous media with multiple spatial scales.

Policy and institutions facilitating entrepreneurial spin-offs: USA, Asia and Europe

2014 ◽  
Vol 3 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Rosa Caiazza ◽  
David Audretsch ◽  
Tiziana Volpe ◽  
Julie Debra Singer
Keyword(s):  
Institutional Setting ◽  
Policy Debate ◽  
Content Type ◽  
Factors Affecting ◽  
Institutional Settings ◽  
The Usa ◽  
New Perspective ◽  
National Analysis ◽  
The Impact ◽  
Cross National

Purpose – Existing work documents the role that institutional setting plays in the process of spin-off creation. However, despite decades of studies, scholars have not clearly explained why some regions are more involved in spin-off activity than others. Drawing from institutional theory, the purpose of this paper is to compare different institutional settings identifying factors affecting the general environment capability to support spin-off activity of a specific region. Design/methodology/approach – The authors utilize a cross-national analysis of American, Asian, and European areas identifying factors affecting their different rate of spin-off activity. This study contributes to the policy debate concerning entrepreneurship and how best to spur spin-off activities. Findings – In this paper, the authors identify the general and specific factors that explain the cross-national diversity in spin-off creation. The authors then perform an analysis of the impact of these factors in various regions of the USA, Asia, and Europe, providing evidence for the necessity of specific combinations of these factors. Originality/value – The paper offers a new perspective on the causes of spin-offs through a cross-national analysis of many areas around the world.

Sign in / Sign up

Export Citation Format

Share Document