scholarly journals Identifying structural connectivity priorities in eastern Paraguay’s fragmented Atlantic Forest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noé U. de la Sancha ◽  
Sarah A. Boyle ◽  
Nancy E. McIntyre
Keyword(s):  
Graph Theory ◽  
Atlantic Forest ◽  
Spatial Scales ◽  
Structural Connectivity ◽  
Theory Approach ◽  
Stepping Stones ◽  
Conservation Action ◽  
Fragmented Forest ◽  
Forest Remnants ◽  
Entire Network

AbstractThe Atlantic Forest of eastern Paraguay has experienced extensive recent deforestation. Less than one-third of the region is forested, and the remaining forest largely consists of isolated remnants with potentially disrupted connectivity for forest fauna. We used a graph theory approach to identify those forest remnants that are important in maintaining landscape structural connectivity for mammals in this fragmented forest. We quantified structural connectivity for forest remnants over the period 2000–2019 at three levels: the entire network of Atlantic Forest remnants in eastern Paraguay; at 10 smaller, nested spatial scales (40–10,000 m) encompassing a range of potential mammalian dispersal abilities; and at the level of individual remnants. We used 10 graph theory metrics to assess aspects of network complexity, dispersal-route efficiency, and individual remnant importance in supporting structural connectivity. We identified forest remnants that serve as important structural connectivity roles as stepping stones, hubs, or articulation points and that should be prioritized for connectivity conservation. Structural connectivity was constrained for organisms incapable of travelling at least 9–12 km (farthest distances between nearest-neighboring forest remnants depending on whether smaller remnants were included or not) and was particularly limited for area-sensitive forest-specialist mammals. With the increased forest loss and fragmentation that is occurring, the connectivity of this system will likely be further compromised, but most of the remnants that we identified as playing important roles for structural connectivity were outside of the country’s proposed “green corridor,” indicating additional areas where conservation action can be directed.

scholarly journals Structural connectivity changes in the motor execution network after stroke rehabilitation

2021 ◽  
pp. 1-9
Author(s):  
Pradeepa Ruwan Wanni Arachchige ◽  
Sadhani Karunarathna ◽  
Abdul Chalik Meidian ◽  
Ryo Ueda ◽  
Wataru Uchida ◽  
...  
Keyword(s):  
Graph Theory ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Recovery Process ◽  
Brain Regions ◽  
Motor Recovery ◽  
Theory Approach ◽  
Precentral Gyrus ◽  
Motor Execution ◽  
Frontal Pole

Background: Although quite a very few studies have tested structural connectivity changes following an intervention, it reflects only selected key brain regions in the motor network. Thus, the understanding of structural connectivity changes related to the motor recovery process remains unclear. Objective: This study investigated structural connectivity changes of the motor execution network following a combined intervention of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) and intensive occupational therapy (OT) after a stroke using graph theory approach. Methods: Fifty-six stroke patients underwent Fugl-Meyer Assessment (FMA), Wolf Motor Function Test-Functional Ability Scale (WMFT-FAS), diffusion tensor imaging (DTI), and T1 weighted imaging before and after the intervention. We examined graph theory measures related to twenty brain regions using structural connectomes. Results: The ipsilesional and contralesional hemisphere showed structural connectivity changes post-intervention after stroke. We found significantly increased regional centralities and nodal efficiency within the frontal pole and decreased degree centrality and nodal efficiency in the ipsilesional thalamus. Correlations were found between network measures and clinical assessments in the cuneus, postcentral gyrus, precentral gyrus, and putamen of the ipsilesional hemisphere. The contralesional areas such as the caudate, cerebellum, and frontal pole also showed significant correlations. Conclusions: This study was helpful to expand the understanding of structural connectivity changes in both hemispheric networks during the motor recovery process following LF-rTMS and intensive OT after stroke.

scholarly journals Detection of areas of endemism on two spatial scales using Parsimony Analysis of Endemicity (PAE): the Neotropical region and the Atlantic Forest

2008 ◽  
Vol 8 (4) ◽  
pp. 33-42 ◽  
Author(s):  
Mário Sérgio Sigrist ◽  
Claudio José Barros de Carvalho
Keyword(s):  
Atlantic Forest ◽  
Spatial Scales ◽  
Distribution Patterns ◽  
Neotropical Region ◽  
Conservation Priorities ◽  
Parsimony Analysis ◽  
Areas Of Endemism ◽  
Endemic Areas ◽  
Analysis Scale ◽  
Parsimony Analysis Of Endemicity

An important biological challenge today is the conservation of biodiversity. Biogeography, the study of the distribution patterns of organisms, is an important tool for this challenge. Endemism, the co-occurrence of several species unique to the same area, has important implications for the preservation of biodiversity, since many areas of endemism are also areas with large human impact. More rigorously defined, areas of endemism are historical units of distributional congruence of monophyletic taxa. These areas often assumed to be due to nonrandom historical events that favored conditions associated with high rates of speciation. Thus, understanding endemism and the delimitation of endemic areas has important implications for conservation. Today, most studies delimit areas of endemism by superimposing maps of distribution for various species. This approach suffers from arbitrary delimitations, however, when a great distributional data is used. In this paper we used the method of Parsimony Analysis of Endemicity (PAE) based on georeferenced quadrats in order to delimit areas of endemism. This modality of the method is important due to its testable nature and can also be used to infer area relationships. We applied the method to raw distributional data from 19 unrelated taxa to delimit general patterns of endemism in the Neotropical Region and in the Atlantic forest domain using different grid scales. Neotropical areas found are comprised over the Panama region, northern Andean region and the Atlantic forest. Atlantic forest showed a major division into two distinct components (northern x southern). Endemic areas delimited using smaller scale grids on the Atlantic forest should be considered for conservation priorities once they showed endemism at regional and local scales. The results were also compared to other studies using different taxa and methods. Finally, some considerations on the analysis scale and future perspectives of the method are presented.

scholarly journals Vulnerability Assessment of a Large Electrical Grid by New Graph Theory Approach

2018 ◽  
Vol 16 (2) ◽  
pp. 527-535 ◽  
Author(s):  
J. BEYZA ◽  
J. M. Yusta ◽  
G. J. Correa ◽  
H. F. Ruiz
Keyword(s):  
Graph Theory ◽  
Vulnerability Assessment ◽  
Theory Approach ◽  
Electrical Grid

scholarly journals Exploring the full catalytic cycle of rhodium(i)–BINAP-catalysed isomerisation of allylic amines: a graph theory approach for path optimisation

2017 ◽  
Vol 8 (6) ◽  
pp. 4475-4488 ◽  
Author(s):  
Takayoshi Yoshimura ◽  
Satoshi Maeda ◽  
Tetsuya Taketsugu ◽  
Masaya Sawamura ◽  
Keiji Morokuma ◽  
...  
Keyword(s):  
Graph Theory ◽  
Reaction Mechanism ◽  
Catalytic Cycle ◽  
Theory Approach ◽  
Allylic Amines ◽  
Reaction Route ◽  
Reaction Method ◽  
Mapping Strategy ◽  
Global Reaction ◽  
Induced Reaction

The reaction mechanism of the cationic rhodium(i)–BINAP complex catalysed isomerisation of allylic amines was explored using the artificial force induced reaction method with the global reaction route mapping strategy.

scholarly journals Conserving woodland caribou habitat while maintaining timber yield: a graph theory approach

2016 ◽  
Vol 46 (7) ◽  
pp. 914-923 ◽  
Author(s):  
Jonathan L.W. Ruppert ◽  
Marie-Josée Fortin ◽  
Eldon A. Gunn ◽  
David L. Martell
Keyword(s):  
Graph Theory ◽  
Rangifer Tarandus ◽  
High Volume ◽  
Timber Harvesting ◽  
Optimization Approach ◽  
Theory Approach ◽  
Heuristic Procedure ◽  
Woodland Caribou ◽  
Old Growth ◽  
Old Growth Forest

The fragmentation and loss of old-growth forest has led to the decline of many forest-dwelling species that depend on old-growth forest as habitat. Emblematic of this issue in many areas of the managed boreal forest in Canada is the threatened woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). We develop a methodology to help determine when and how timber can be harvested to best satisfy both industrial timber supply and woodland caribou habitat requirements. To start, we use least-cost paths based on graph theory to determine the configuration of woodland caribou preferred habitat patches. We then developed a heuristic procedure to schedule timber harvesting based on a trade-off between merchantable wood volume and the remaining amount of habitat and its connectivity during a planning cycle. Our heuristic can attain 84% of the potential woodland caribou habitat that would be available in the absence of harvesting at the end of a 100 year planning horizon. Interestingly, this is more than that which is attained by the current plan (50%) and a harvesting plan that targets high volume stands (32%). Our results indicate that our heuristic procedure (i.e., an ecologically tuned optimization approach) may better direct industrial activities to improve old-growth habitat while maintaining specified timber production levels.

Nematodes of Amphisbaena vermicularis Wagler, 1824 (Squamata, Amphisbaenidae) from Brazilian Atlantic Forest remnants

2021 ◽  
Vol 55 (19-20) ◽  
pp. 1227-1236
Author(s):  
Leonardo Pessoa Cabus Oitaven ◽  
Geraldo Jorge Barbosa de Moura ◽  
Felipe da Silva Ribeiro ◽  
Elizardo Batista Ferreira Lisboa ◽  
Jaqueline Bianque Oliveira
Keyword(s):  
Atlantic Forest ◽  
Brazilian Atlantic Forest ◽  
Forest Remnants
Sign in / Sign up

Export Citation Format

Share Document