scholarly journals Assessing Landscape Sensitivity Based on Fragmentation Caused by the Artificial Barriers in Hungary

2013 ◽  
Vol 6 (1-2) ◽  
pp. 37-47 ◽  
Author(s):  
Teodóra Bata ◽  
Gábor Mezősi
Keyword(s):  
Landscape Metrics ◽  
Patch Size ◽  
Mesh Size ◽  
Landscape Fragmentation ◽  
Effective Population ◽  
Landscape Unit ◽  
Landscape Sensitivity ◽  
The Stability ◽  
Landscape Units ◽  
Degree Of Fragmentation

Abstract Artificial barriers significantly disturb the landscape unit. Roads split the contiguous landscape units, thus basically modi fying their ecological characters. The more artificial barriers are constructed in the landscape, the more fragmented it is. Theref ore, the contiguous landscape unit is divided into two or more patches, weakening resilience and stability of ecological systems. During decrease in patch size, the stability reduces until the patch size is at its minimum viable or effective population size. In current study analysing the degree of fragmentation caused by artificial barriers in meso-scale landscape units (meso-regions) we can get an overall picture about changes in their stability and sensitivity. The major aims of this study is to investigate the fragmentation of landscape units caused by three types of artificial barriers (roads, railways and settlements) in micro-regions, and to measure the degree of fragmentation and its spatial-temporal (1990, 2011 and future scenario to 2027) changes using mathemat ical/ statistical analysis and landscape metrics (Number of Patches, Division, Landscape Splitting Index and Effective Mesh Size). By calculating landscape fragmentation metrics, the micro-regions are identified, which must be protected with high priority in the future. In the planning processes, type and position of artificial barriers could be more properly determined by calculation of these landscape metrics.

scholarly journals The Extent of Infrastructure Causing Fragmentation in the Hydrocarbon Basin in the Arid and Semi-Arid Zones of Patagonia (Argentina)

2019 ◽  
Vol 11 (21) ◽  
pp. 5956
Author(s):  
Buzzi ◽  
Rueter ◽  
Ghermandi ◽  
Lasaponara
Keyword(s):  
Principal Component ◽  
Mesh Size ◽  
Oil Production ◽  
Landscape Fragmentation ◽  
Arid Zones ◽  
Effective Mesh Size ◽  
The Mean ◽  
Patch Density ◽  
Landscape Units ◽  
Semi Arid

Fragmentation is a disruption in the connectivity of landscapes. The aims of this paper are (i) to quantitatively assess the fragmentation rates in three landscape units located in a hydrocarbon basin, and (ii) to model their behavior between 2001 and 2013 using landscape metrics at different scales of resolution. The following metrics were selected using principal component analysis (PCA): The Clumpiness Index (CLUMPY), patch density (PD), perimeter-area fractal dimension (PAFRAC) and effective mesh size (MESH). Results from our investigations pointed out that hydrocarbon activity increased the fragmentation at the sites. In particular, the CLUMPY index increased in all three landscape units, the average of PD decreased from 60 to 14 patches per 100 hectares, whereas the mean of MESH was quite constant, however, due to oil production, it decreased mainly in the coastal valleys. Finally, the PAFRAC also decreased at sites with oil production, being more evident in the plateau and coastal canyons. As a whole, outputs from our analyses clearly pointed out that the monitoring of landscape fragmentation trends in arid and semi-arid zones can be successfully achieved using metrics derived from satellite spectral information.

Modification of the effective mesh size for measuring landscape fragmentation to solve the boundary problem

2006 ◽  
Vol 22 (3) ◽  
pp. 447-459 ◽  
Author(s):  
Brigitte Moser ◽  
Jochen A. G. Jaeger ◽  
Ulrike Tappeiner ◽  
Erich Tasser ◽  
Beatrice Eiselt
Keyword(s):  
Boundary Problem ◽  
Mesh Size ◽  
Landscape Fragmentation ◽  
Effective Mesh Size

Infection levels of the cestode Hymenolepis diminuta in rat populations from Buenos Aires, Argentina

2015 ◽  
Vol 90 (2) ◽  
pp. 199-205 ◽  
Author(s):  
D. Hancke ◽  
O.V. Suárez
Keyword(s):  
Body Length ◽  
Buenos Aires ◽  
Negative Binomial ◽  
Hymenolepis Diminuta ◽  
Intermediate Hosts ◽  
Residential Areas ◽  
Landscape Unit ◽  
Large Populations ◽  
Landscape Units ◽  
Zoonotic Parasites

AbstractEcological studies on zoonotic parasites are crucial for the design and implementation of effective measures to prevent parasite transmission. The aim of this study was to evaluate factors such as season, landscape unit, rat sex and rat body length, affecting the abundance of the cestode Hymenolepis diminuta, a parasite of synanthropic rats, within an urban environment. A parasitological survey was undertaken on 169 rats from landscape units such as shantytowns, parklands, industrial–residential areas and scrap-metal yards in Buenos Aires, Argentina. The overall prevalence of H. diminuta was 21.3%, although the occurrence of this species in rats was not homogeneous. The abundance of H. diminuta, using a zero-inflated negative binomial model, was correlated with rat body length. In shantytowns, abundance levels were higher than other landscape units, largely due to differences in individual environmental characteristics and rat assemblages. The populations of arthropod intermediate hosts could be subjected to seasonal fluctuations and the degree of urbanization. Shantytowns are overcrowded urban marginal settlements with most inhabitants living in precarious conditions and supporting large populations of rats, thereby increasing the risk of zoonotic infection.

Landscape and patch attributes impacting medium- and large-sized terrestrial mammals in a fragmented rain forest

2013 ◽  
Vol 29 (4) ◽  
pp. 331-344 ◽  
Author(s):  
Adriana Garmendia ◽  
Víctor Arroyo-Rodríguez ◽  
Alejandro Estrada ◽  
Eduardo J. Naranjo ◽  
Kathryn E. Stoner
Keyword(s):  
Landscape Metrics ◽  
Rain Forest ◽  
Patch Size ◽  
Forest Cover ◽  
Sampling Site ◽  
Edge Density ◽  
Forest Cover Change ◽  
Terrestrial Mammals ◽  
Number Of Species ◽  
Matrix Quality

Abstract:Understanding the response of biodiversity to land-use changes is an important challenge for ecologists. We assessed the effects of five landscape metrics (forest cover, number of patches, edge density, mean inter-patch isolation distance and matrix quality) and three patch metrics (patch size, shape and isolation) on the number of species and patch occupancy of medium- and large-sized terrestrial mammals in the fragmented Lacandona rain forest, Mexico. We sampled mammal assemblages in 24 forest patches and four control areas within a continuous forest. The landscape metrics were measured within a 100-ha buffer, and within a 500-ha buffer from the centre of each sampling site. A total of 21 species from 13 families was recorded. The number of species increased with shape complexity and patch size at the patch scale, and with matrix quality within 100-ha landscapes. When considering 500-ha landscapes, only the number of patches (i.e. forest fragmentation level) tended to have a negative influence at the community level. Different landscape and patch metrics predicted the occurrence of each species within the sites. Our results indicate that there is a gradient of tolerance to forest cover change, from highly sensitive species to those tolerant of, or even benefited by, forest-cover change.

Association of vascular epiphytes with landscape units and phorophytes in humid lowland forests of Colombian Amazonia

2011 ◽  
Vol 27 (03) ◽  
pp. 223-237 ◽  
Author(s):  
A. M. Benavides ◽  
A. Vasco ◽  
A. J. Duque ◽  
J. F. Duivenvoorden
Keyword(s):  
Species Composition ◽  
Detrended Correspondence Analysis ◽  
Individual Species ◽  
Randomization Tests ◽  
Host Preferences ◽  
Vascular Epiphytes ◽  
Landscape Unit ◽  
Lowland Forests ◽  
Landscape Units ◽  
Epiphyte Species

Abstract:The species composition of vascular epiphytes and phorophytes (trees and lianas) was studied in ten 0.1-ha forest plots distributed over three landscape units (floodplains, swamps and well-drained uplands) in Colombian Amazonia. The aim was to analyse how host-preferences contributed to the patterns in epiphyte assemblages among the landscape units. In the plots 82 species (3310 plants) were holo-epiphytes, 11 species were primary hemi-epiphytes (179 plants) and 61 were secondary hemi-epiphytes (2337 plants). A total of 411 species of tree and liana were recorded as phorophytes. Detrended Correspondence Analysis and Mantel tests showed that the species composition of holo-epiphytes and secondary hemi-epiphytes differed among the landscape units. For both groups the effect of landscape unit on species composition strongly decreased after controlling for the phorophyte composition in the plots. The phorophyte composition significantly explained epiphyte composition and this effect was not removed after accounting for the effect of landscape unit. At the level of individual species, randomization tests yielded only few significant epiphyte–phorophyte associations. For 84% of the epiphyte species the average indicator of patchiness was below 1.5 demonstrating that most epiphyte individuals occurred scattered over different phorophytes. This probably hampered the analyses of host preferences for individual epiphyte species.

scholarly journals Implementation of natural disturbance-based management in northern British Columbia

2007 ◽  
Vol 83 (3) ◽  
pp. 338-346 ◽  
Author(s):  
S. Craig DeLong
Keyword(s):  
British Columbia ◽  
Key Words ◽  
Size Distribution ◽  
Patch Size ◽  
Natural Disturbance ◽  
Timber Supply ◽  
Stage Distribution ◽  
Natural Range ◽  
Landscape Units ◽  
Northeast Corner

Ecologically based landscape units and associated characteristics of natural disturbance (e.g., seral stage and patch size distribution) were recently developed for the northeast corner of British Columbia and used as the basis for establishing guidance and policy for natural disturbance-based management for two large timber supply areas. I discuss the development of the landscape units; development of guidance for the units; and implementation of the guidance for old forest, interior old forest, and early seral patch size objectives. This paper demonstrates how natural-disturbance-based management can be successfully implemented. Key words: natural-disturbance-based management, natural range of variability, seral stage distribution, old-forest requirements, patch size, guidance, implementation

scholarly journals Landscape Fragmentation around Ferruginous Caves of the Iron Quadrangle, Minas Gerais, Brazil

2019 ◽  
Vol 28 (1) ◽  
pp. 89-101 ◽  
Author(s):  
Mauro Gomes ◽  
Úrsula De Azevedo Ruchkys ◽  
Rodrigo Lopes Ferreira ◽  
Fernando Figueiredo Goulart
Keyword(s):  
Edge Effects ◽  
Landscape Fragmentation ◽  
Minas Gerais ◽  
Environmental Stability ◽  
Vegetation Coverage ◽  
Map Algebra ◽  
Research Article ◽  
Iron Quadrangle ◽  
Low Degree ◽  
Degree Of Fragmentation

The aim of this article is to analyse the landscape fragmentation around ferruginous caves in the Iron Quadrangle (Minas Gerais, Brazil) and the conditions of environmental stability of the caves inserted in vegetal remnants under edge effects caused by anthropic activities. The methodology applied involved the implementation of three different landscape metrics to stablish the total area of patches, the area of the patches under edge effects (core area), and the distance from the nearest neighbour. The measurements were calculated considering classes of vegetal coverage (herbaceous, shrub, and arboreal vegetation) and then processed and combined by using map algebra to obtain the fragmentation degree, which was classified into three classes: high, moderate, and low. Results reveal that 62.88% of the vegetation coverage of the study area presents a low degree of fragmentation. Among the caves under edge effects, 15% obtained negative indices of environmental stability. Although most of the analysed caves are located in areas with a low degree of fragmentation, the proximity of anthropized areas and the risk they represent for the speleological heritage reinforce the need to create strategies focused on the conservation of the caves.Featured ideas: research article on the results of research carried out regarding the composition and configuration of the landscape surrounding ferruginous caves located in the Iron Quadrangle, in the state of Minas Gerais, Brazil.

scholarly journals Stability of a Leap-Frog Discontinuous Galerkin Method for Time-Domain Maxwell's Equations in Anisotropic Materials

2017 ◽  
Vol 21 (5) ◽  
pp. 1350-1375 ◽  
Author(s):  
Adérito Araújo ◽  
Sílvia Barbeiro ◽  
Maryam Khaksar Ghalati
Keyword(s):  
Galerkin Method ◽  
Discontinuous Galerkin ◽  
Discontinuous Galerkin Method ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Mesh Size ◽  
Element Space ◽  
First Order ◽  
Balance Accuracy ◽  
The Stability

AbstractIn this work we discuss the numerical discretization of the time-dependent Maxwell's equations using a fully explicit leap-frog type discontinuous Galerkin method. We present a sufficient condition for the stability and error estimates, for cases of typical boundary conditions, either perfect electric, perfect magnetic or first order Silver-Müller. The bounds of the stability region point out the influence of not only the mesh size but also the dependence on the choice of the numerical flux and the degree of the polynomials used in the construction of the finite element space, making possible to balance accuracy and computational efficiency. In the model we consider heterogeneous anisotropic permittivity tensors which arise naturally in many applications of interest. Numerical results supporting the analysis are provided.

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