scholarly journals Connectivity Study in Northwest Spain: Barriers, Impedances, and Corridors

2019 ◽  
Vol 11 (18) ◽  
pp. 5124
Author(s):  
Enrique Valero ◽  
Xana Álvarez ◽  
Juan Picos
Keyword(s):  
Brown Bear ◽  
Genetic Exchange ◽  
Distribution Area ◽  
Species Dispersal ◽  
Natural Habitats ◽  
Critical Areas ◽  
Connectivity Probability ◽  
Connectivity Indices ◽  
Cost Paths ◽  
Least Cost Paths

Functional connectivity between habitats is a fundamental quality for species dispersal and genetic exchange throughout their distribution range. Brown bear populations in Northwest Spain comprise around 200 individuals separated into two sub-populations that are very difficult to connect. We analysed the fragmentation and connectivity for the Ancares-Courel Site of Community Importance (SCI) and its surroundings, including the distribution area for this species within Asturias and in the northwest of Castile and León. The work analysed the territory’s connectivity by using Geographic Information Systems (GIS). The distance-cost method was used to calculate the least-cost paths with Patch Matrix. The Conefor Sensinode software calculated the Integral Connectivity Index and the Connectivity Probability. Locating the least-cost paths made it possible to define areas of favourable connectivity and to identify critical areas, while the results obtained from the connectivity indices led to the discovery of habitat patches that are fundamental for maintaining connectivity within and between different spaces. Three routes turned out to be the main ones connecting the northern (Ancares) and southern (Courel) areas of the SCI. Finally, this work shows the importance of conserving natural habitats and the biology, migration, and genetic exchange of sensitive species.

scholarly journals INTERACTIVE CADASTRAL BOUNDARY DELINEATION FROM UAV DATA

2018 ◽  
Vol IV-2 ◽  
pp. 81-88 ◽  
Author(s):  
S. Crommelinck ◽  
B. Höfle ◽  
M. N. Koeva ◽  
M. Y. Yang ◽  
G. Vosselman
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Land Tenure ◽  
State Of The Art ◽  
Cost Effective ◽  
Contour Detection ◽  
Local Boundary ◽  
Manual Delineation ◽  
Cost Paths ◽  
Cadastral Surveying ◽  
Least Cost Paths

Unmanned aerial vehicles (UAV) are evolving as an alternative tool to acquire land tenure data. UAVs can capture geospatial data at high quality and resolution in a cost-effective, transparent and flexible manner, from which visible land parcel boundaries, i.e., cadastral boundaries are delineable. This delineation is to no extent automated, even though physical objects automatically retrievable through image analysis methods mark a large portion of cadastral boundaries. This study proposes (i) a methodology that automatically extracts and processes candidate cadastral boundary features from UAV data, and (ii) a procedure for a subsequent interactive delineation. Part (i) consists of two state-of-the-art computer vision methods, namely gPb contour detection and SLIC superpixels, as well as a classification part assigning costs to each outline according to local boundary knowledge. Part (ii) allows a user-guided delineation by calculating least-cost paths along previously extracted and weighted lines. The approach is tested on visible road outlines in two UAV datasets from Germany. Results show that all roads can be delineated comprehensively. Compared to manual delineation, the number of clicks per 100 m is reduced by up to 86 %, while obtaining a similar localization quality. The approach shows promising results to reduce the effort of manual delineation that is currently employed for indirect (cadastral) surveying.

Bison Jump Location is Primarily Predicted by Minimizing Visibility at the Wold Site, Johnson County, Wyoming

2016 ◽  
Vol 81 (4) ◽  
pp. 752-763 ◽  
Author(s):  
Brigid S. Grund ◽  
Spencer R. Pelton ◽  
Todd A. Surovell ◽  
Neffra A. Matthews ◽  
Tommy A. Noble
Keyword(s):  
Great Plains ◽  
Cross Sections ◽  
Steep Slope ◽  
Bison Bison ◽  
Visibility Analysis ◽  
Johnson County ◽  
Cost Paths ◽  
The Cost ◽  
Least Cost Paths

The Wold Bison Jump (48JO966) is a communal bison (Bison bison) hunting site in Johnson County, Wyoming. It likely represents a single kill event precipitated by Great Plains foragers between A.D. 1433 and 1643. Operating the jump required that prehistoric hunters drive stampeding bison up a steep slope in order to position them within a V-shaped drive line configured to funnel them toward a cliff. Using iterative models of least cost paths, topographic cross-sections, and visibility analysis, we test which landscape-embedded variables are optimized at the jump site as compared to other potential localities across the study area. We find that this site’s placement is primarily explained by minimizing the distance at which the cliff face is visible and secondarily by minimizing the cost of slope and curvature routes ascending into the drive lines. Our procedure could hypothetically be used to predict optimal jump locations on similar landscapes.

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