184 results on '"Spatial connectivity"'
Search Results
2. Cast from the Past? Microbial Diversity of a Neolithic Stone Circle.
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Martín-Cereceda, Mercedes, de Cos-Gandoy, Amaya, Williams, Richard A. J., Elliott, David, Serrano-Bellón, Andrea, Pérez-Uz, Blanca, and Sanchez-Jimenez, Abel
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MICROBIAL diversity ,EUKARYOTES ,MOUNDS (Archaeology) ,ARCHAEBACTERIA ,GREEN algae - Abstract
We studied the microbial diversity colonizing limestone rock pools at a Neolithic Monument (Arbor Low, Derbyshire, England). Five pools were analyzed: four located at the megaliths of the stone circle and one pool placed at the megalith at the Gib Hill burial mound 300 m distant. Samples were taken from rock pool walls and sediments, and investigated through molecular metabarcoding. The microbiome consisted of 23 phyla of bacteria (831 OTUs), 4 phyla of archaea (19 OTUs), and 27 phyla of microbial eukarya (596 OTUs). For bacteria, there were statistically significant differences in wall versus sediment populations, but not between pools. For archaea and eukarya, significant differences were found only between pools. The most abundant bacterial phylum in walls was Cyanobacteriota, and Pseudomonadota in sediments. For archaea and microbial eukarya, the dominant phyla were Euryarcheota and Chlorophyta, respectively, in both wall and sediments. The distant pool (P5) showed a markedly different community structure in phyla and species, habitat discrimination, and CHN content. Species sorting and dispersal limitation are discussed as mechanisms structuring the microbiome assemblages and their spatial connectivity. The Arbor Low microbiome is composed of terrestrial representatives common in extreme environments. The high presence of Cyanobacteriota and Chlorophyta in the Arbor Low stones is troubling, as these microorganisms can induce mechanical disruption by penetrating the limestone matrix through endolithic/chasmoendolithic growth. Future research should focus on the metabolic traits of strains to ascertain their implication in bioweathering and/or biomineralization. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
3. Characteristics, residency and site fidelity of photo-identified reef manta rays (Mobula alfredi) population in New Caledonia.
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Lassauce, Hugo, Chateau, Olivier, and Wantiez, Laurent
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- *
MOBULIDAE , *WORLD records , *WOUNDS & injuries , *SPECIES distribution , *PREDATION , *ARCHIPELAGOES , *CORAL bleaching - Abstract
Reef manta rays (Mobula alfredi) face threats from human exploitation and activity in several regions of the world and crucial information on the ecology of the species is needed. The species is observed at several sites in all parts of the archipelago of New Caledonia where anthropogenic influence is presumed to be minimal. This study is the first to investigate the population of New Caledonia and focuses on its characteristics and its habitat use. Photographs of reef manta rays were collected directly from the authors (14.4%) between 2017 and 2020 and gathered from recreational divers and snorkelers (85.6%) from 11 sites around New Caledonia. The authors used the unique ventral coloration patterns of the manta rays that were clearly identifiable from 1741 of these photographs to identify 391 individuals and record their physical characteristics (sex, injuries, and colour morph) and resighting rates. These results highlight the widespread distribution of the species in the archipelago (11 sites) with little connectivity between all aggregations sites, with only 5.4% of the individuals observed at more than one site. Strong and long-term site fidelity was recorded at all studied sites through re-sighting rates (52.2% overall) and residency analysis. The population also records the world highest known proportion of melanistic manta rays (43%) to date, and a balanced male: female ratio (1.0:1.15). The analysis of injuries reported that 44.8% of all reef manta rays identified (n = 391) had noticeable wounds or injuries with no significant difference in the proportions of males and females injured. From these injured individuals only 9.8% of injuries judged to be of anthropogenic origin and 29.7% from attempted predation. Our study complements and correlates previous findings on this population that revealed strong site fidelity and low connectivity. The different characteristics of this population of reef manta rays also emphasize that concerns about species in New Caledonia are limited and that such favourable context needs to be preserved as reference for conservation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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4. The topology of spatial networks affects stability in experimental metacommunities.
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Arancibia, Paulina A.
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BIOTIC communities , *CONTRAST effect , *BIOMASS , *SYNCHRONIC order , *TOPOLOGY - Abstract
Understanding the drivers of community stability has been a central goal in ecology. Traditionally, emphasis has been placed on studying the effects of biotic interactions on community variability, and less is understood about how the spatial configuration of habitats promotes or hinders metacommunity stability. To test the effects of contrasting spatial configurations on metacommunity stability, I designed metacommunities with patches connected as random or scale-free networks. In these microcosms, two prey and one protist predator dispersed, and I evaluated community persistence, tracked biomass variations, and measured synchrony between local communities and the whole metacommunity. After 30 generations, scale-free metacommunities had lower global biomass variability and higher persistence, suggesting higher stability. Synchrony between patches was lower in scale-free metacommunities. Patches in scale-free metacommunities showed a positive relationship between variability and patch connectivity, indicating higher stability in isolated communities. No clear relationship between variability and patch connectivity was observed in random networks. These results suggest the increased heterogeneity in connectivity of scale-free networks favours the prevalence of isolated patches of the metacommunity, which likely act as refugia against competition—the dominant interaction in this system—resulting in higher global stability. These results highlight the importance of accounting for network topology in the study of spatial dynamics. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Connectivity of the Regions of the South of Western Siberia in the Indicators of Population Spatial Mobility.
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Cherkashina, T. Yu., Mosienko, N. L., and Kalashnikova, K. N.
- Abstract
The article presents the results of a study of the connectivity of the regions of the South of Western Siberia based on the indicators of population spatial mobility—one type of interregional interactions. The types of subregional and interregional connected spaces, including conurbations, are described. The possibilities of using various data sources to study the spatial mobility of Russians are shown. The socioeconomic and infrastructural features of the regions of the South of Western Siberia are also described. Data on travel time between regional centers when traveling by car, bus, or train were analyzed. It was revealed that the time spent traveling between such cities is minimal by car. The transport connectivity of all cities with Novosibirsk is better than with each other, which indicates that the space of the South of Western Siberia is monocentric for this indicator. To determine the migration links of Siberian regions based on Federal State Statistics Service (Rosstat) data, the values of the coefficients of interregional migration links intensity were calculated in pairs between regions. Closer migration links between the regions of the Western Siberia's South show their connectivity, and the presence of several pairs of territories among them with more intense migration links indicates the polycentric nature of macroregional migration interactions. Based on sociological data obtained in telephone surveys with people in Tomsk oblast and Altai krai in 2021, spatial mobility is described using the case of occasional trips outside the region according to such parameters as intensity, direction, modes of transport used, and purpose of travel. It was revealed that the structure of priority directions of occasional mobility coincides with the directions of intensive migration movements. Among the vehicles used on occasional trips, passenger vehicles predominate; the key purposes of occasional mobility are social, recreational, and work. The analysis shows that spatial connectivity through the population mobility is ensured largely due to the desire to maintain social contacts. [ABSTRACT FROM AUTHOR]
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- 2024
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6. The effect of local habitat and spatial connectivity on urban seed predation.
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Gaytán, Álvaro, van Dijk, Laura J. A., Faticov, Maria, Barr, Anna E., and Tack, Ayco J. M.
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FOREST litter , *GRANIVORES , *ENGLISH oak , *INSECT diversity , *HABITATS , *URBAN plants , *PREDATION - Abstract
Premise: During the last centuries, the area covered by urban landscapes is increasing all over the world. Urbanization can change local habitats and decrease connectivity among these habitats, with important consequences for species interactions. While several studies have found a major imprint of urbanization on plant–insect interactions, the effects of urbanization on seed predation remain largely unexplored. Methods: We investigated the relative impact of sunlight exposure, leaf litter, and spatial connectivity on predation by moth and weevil larvae on acorns of the pedunculate oak across an urban landscape during 2018 and 2020. We also examined whether infestations by moths and weevils were independent of each other. Results: While seed predation varied strongly among trees, seed predation was not related to differences in sunlight exposure, leaf litter, or spatial connectivity. Seed predation by moths and weevils was negatively correlated at the level of individual acorns in 2018, but positively correlated at the acorn and the tree level in 2020. Conclusions: Our study sets the baseline expectation that urban seed predators are unaffected by differences in sunlight exposure, leaf litter, and spatial connectivity. Overall, our findings suggest that the impact of local and spatial factors on insects within an urban context may depend on the species guild. Understanding the impact of local and spatial factors on biodiversity, food web structure, and ecosystem functioning can provide valuable insights for urban planning and management strategies aimed at promoting urban insect diversity. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Insights into the visitations of oceanic manta rays at cleaning stations on coral reefs in the Bird's Head Seascape, eastern Indonesia
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Edy Setyawan, Ronald Mambrasar, Abraham B. Sianipar, Abdy W. Hasan, Mochamad I. H. Putra, Imanuel Mofu, Calvin S. Beale, and Mark V. Erdmann
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spatial connectivity ,passive acoustic telemetry ,marine megafauna ,site fidelity ,marine protected areas (MPAs) ,endangered species (EN) ,Aquaculture. Fisheries. Angling ,SH1-691 - Abstract
The globally endangered oceanic manta ray Mobula birostris is believed to spend significantly more time in the open ocean than in coastal areas. Nonetheless, the Bird's Head Seascape (BHS) in eastern Indonesia hosts a large population of this species (over 850 individuals), frequently sighted at coral reef cleaning stations and forming a vital asset for marine tourism in the region. Despite this, detailed understanding of the movements and habitat use of this wide-ranging species within shallow (< 30 m) coral reef ecosystems remains limited. Addressing this knowledge gap is urgently required for the sustainable management of oceanic manta ray-focused tourism in the region. Here, we report the results of an initial passive acoustic telemetry study investigating the use of coral reef cleaning stations by oceanic manta rays. Forty-one rays were acoustically tracked from February 2016 to August 2019 in an array of 28 acoustic receivers deployed at known cleaning stations and hypothesized transit points across the BHS (including the regions of Raja Ampat, Fakfak, and Kaimana). A total of 5,822 detections were recorded by 16 of the 28 receivers from all tagged individuals, and 421 visitation events were documented from 37 out of the 41 tagged individuals, providing valuable insights into their visitation patterns at cleaning stations. Tagged individuals were detected at receiver stations for durations ranging from 0.2 to 427.0 min (mean ± SD = 48 ± 64 min). Notably, 94% of detections were recorded during daylight hours (reaching a peak at noon), underscoring an apparent diurnal pattern in time spent around cleaning stations. The study documented frequent short-range movements between adjacent receivers (5–12 km apart), with two-thirds of all 191 tracked movements occurring between neighboring stations in southern Raja Ampat. Notably, tagged individuals were detected repeatedly at three cleaning stations which were previously only known for hosting reef manta rays, suggesting oceanic manta rays likely also utilize these cleaning stations. Our study provides important insights into the visitations and local movements of oceanic manta rays between coral reef cleaning stations, which will inform effective oceanic manta ray conservation efforts and tourism management in the BHS.
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- 2024
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8. Urban Infrastructure Issues: A Sustainable Alley Development and Construction in Viet Nam
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Dang, Ngoc Thao Linh, Truong, Ngoc Son, Truong, Ngoc Toan, Do, Thi Tra, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Reddy, J. N., editor, Luong, Van Hai, editor, and Le, Anh Tuan, editor
- Published
- 2023
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9. Navigating through space and time: A methodological approach to quantify spatiotemporal connectivity using stream flow data as a case study
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David Cunillera‐Montcusí, José María Fernández‐Calero, Sebastian Pölsterl, Roger Argelich, Pau Fortuño, Núria Cid, Núria Bonada, and Miguel Cañedo‐Argüelles
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ephemeral streams ,intermittent rivers ,network structure ,spatial connectivity ,spatiotemporal graphs ,temporal connectivity ,Ecology ,QH540-549.5 ,Evolution ,QH359-425 - Abstract
Abstract The growing interest in combining spatial and temporal patterns in nature has been fostered by the current availability of high‐frequency measurements. However, we still lack a methodological framework to process and interpret spatiotemporal datasets into meaningful values, adaptable to different time windows and/or responding to different spatial structures. Here, we developed and tested a framework to evaluate spatiotemporal connectivity using two new measures: the spatiotemporal connectivity (STcon) and the spatiotemporal connectivity matrix (STconmat). To obtain these measures, we consider a set of spatially connected sites within a temporally dynamic network. These measures are calculated from a spatiotemporal matrix where spatial and temporal connections across sites are captured. These connections respond to a determined network structure, assign different values to these connections and generate different scenarios from which we obtain the spatiotemporal connectivity. We developed these measures by using a dataset of stream flow state spanning a 513‐day period obtained from data loggers installed in seven temporary streams. These measures allowed us to characterise connectivity among stream reaches and relate spatiotemporal patterns with macroinvertebrate community structure and composition. Spatiotemporal connectivity differed within and among streams, with STcon and STconmat capturing different hydrological patterns. Macroinvertebrate richness and diversity were higher in more spatiotemporally connected sites. Community dissimilarity was related to STconmat showing that more spatiotemporally connected sites had similar communities for active and passive dispersers. Interestingly, both groups were related to spatiotemporal connectivity patterns for some of the analysed scenarios, highlighting the relevance of spatiotemporal connectivity in dynamic systems. As we exemplified, the proposed framework can help to disentangle and quantify spatiotemporal dynamics or be applied in the conservation of dynamic systems such as temporary streams. However, the current framework is not limited to the temporal and spatial features of temporary streams. It can be extended to other ecosystems by including different time windows and/or consider different network structures to assess spatiotemporal patterns. Such spatiotemporal measures are especially relevant in a context of global change, with the spatiotemporal dynamics of ecosystems being heavily disrupted by human activities.
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- 2023
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10. Assessing 2D visual encoding of 3D spatial connectivity
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Benedetta F. Baldi, Jenny Vuong, and Seán I. O’Donoghue
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visual encoding ,user study ,visual analytics ,spatial connectivity ,chromatin organization ,circular layout ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
Introduction: When visualizing complex data, the layout method chosen can greatly affect the ability to identify outliers, spot incorrect modeling assumptions, or recognize unexpected patterns. Additionally, visual layout can play a crucial role in communicating results to peers.Methods: In this paper, we compared the effectiveness of three visual layouts—the adjacency matrix, a half-matrix layout, and a circular layout—for visualizing spatial connectivity data, e.g., contacts derived from chromatin conformation capture experiments. To assess these visual layouts, we conducted a study comprising 150 participants from Amazon’s Mechanical Turk, as well as a second expert study comprising 30 biomedical research scientists.Results: The Mechanical Turk study found that the circular layout was the most accurate and intuitive, while the expert study found that the circular and half-matrix layouts were more accurate than the matrix layout.Discussion: We concluded that the circular layout may be a good default choice for visualizing smaller datasets with relatively few spatial contacts, while, for larger datasets, the half- matrix layout may be a better choice. Our results also demonstrated how crowdsourcing methods could be used to determine which visual layouts are best for addressing specific data challenges in bioinformatics.
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- 2024
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11. A (Long) Tale of Two Leaders: Charting the Spatial and Sectoral Roles of the West and China in Shaping Past, Present and Future Economic Globalization(s).
- Author
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Chen, Xiangming
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ECONOMIC globalization ,BELT & Road Initiative ,RUSSIAN invasion of Ukraine, 2022- ,CHINA-United States relations ,REGIONAL differences ,GREAT powers (International relations) ,INFRASTRUCTURE (Economics) - Abstract
Globalization has run into two intersected momentous shifts over the past decade. One is an accelerating retreat in the Western-led economic globalization. The other is the continued surge of China as a leader of alternative economic globalization, via the Belt and Road Initiative. These two powerful trends are complicated by COVID-19 and the Ukraine war with their disruptions of global geopolitics, plus a potential technological decoupling between China and the United States as great-power rivals. This unprecedented combination of challenges and crises occasions a fresh analysis of the roles of the West versus China in shaping economic globalization past and present. Against the state-centric approach to globalization, I develop a historically-informed framework to couple spatial and sectoral analyses of the trajectories of economic globalization shaped by the West and China. I first examine the cross-regional dimensions of economic globalization across Eurasia featuring China's primary role in driving the China-Europe Freight Train. I then explore China's exceptional strength in delivering overseas infrastructure projects, as embodied by the China-Laos Railway, relative to the West's sectoral advantages bearing on economic globalization. Lastly, I summarily discuss the past and present roles of the West versus China in producing new divergence in future economic globalization. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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12. 中国与"一带一路"沿线国家空间联通水平 差异与成因分析.
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肖懿晨, 文军, 李玲玉, and 冯庆旺
- Subjects
ROADS - Abstract
Copyright of Arid Land Geography is the property of Chinese Academy of Sciences, Xinjiang Institute of Ecology & Geography and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2023
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13. Urban street network and data science based spatial connectivity evaluation of African cities: implications for sustainable urban development.
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Mengistie, Bewketu Mamaru, Shi, WenZhong, Wong, Man Sing, and Zhu, Rui
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SUSTAINABLE urban development ,CENTRAL business districts ,CITIES & towns ,DATA science ,ANIMAL population density ,SOCIOECONOMIC status - Abstract
The aim of the study was to evaluate spatial connectivity and socioeconomic status of African cities using street network datasets and geospatial methods. The drivable street network was collected from OpenStreetMap, and spatial connectivity has developed at the cityscape level and central business districts (CBD). At the cityscape level, almost all studied cities have minimum spatial connectivity as illustrated by metrics like betweenness centrality, average node average and intersection density metrics where maximum values were 0.11, 6.28 and 359 nodes/km2 respectively. The spatial connectivity of CBD was higher compared cityscape level, which indicated the availability unbalanced growth of drivable street network in the sample cities. Moreover, the study has also founded relationship between spatial connectivity and socioeconomic status of cities which in turn have implications to the sustainability of urban areas. [ABSTRACT FROM AUTHOR]
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- 2023
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14. Fit-for-Purpose Information for Offshore Wind Farming Applications—Part-I: Identification of Needs and Solutions.
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She, Jun, Blauw, Anouk, Laakso, Lauri, Mourre, Baptiste, Schulz-Stellenfleth, Johannes, and Wehde, Henning
- Subjects
OFFSHORE wind power plants ,WIND power ,ECOLOGICAL assessment ,SUBMARINE cables ,BIODIVERSITY conservation ,ENVIRONMENTAL protection ,AGRICULTURAL technology - Abstract
The rapid expansion of offshore wind farms (OWFs) in European seas is accompanied by many challenges, including efficient and safe operation and maintenance, environmental protection, and biodiversity conservation. Effective decision-making for industry and environmental agencies relies on timely, multi-disciplinary marine data to assess the current state and predict the future state of the marine system. Due to high connectivity in space (land–estuarial–coastal sea), socioeconomic (multi-sectoral and cross-board), and environmental and ecological processes in sea areas containing OWFs, marine observations should be fit for purpose in relation to multiple OWF applications. This study represents an effort to map the major observation requirements (Part-I), identify observation gaps, and recommend solutions to fill those gaps (Part-II) in order to address multi-dimension challenges for the OWF industry. In Part-I, six targeted areas are selected, including OWF operation and maintenance, protection of submarine cables, wake and lee effects, transport and security, contamination, and ecological impact assessments. For each application area, key information products are identified, and integrated modeling–monitoring solutions for generating the information products are proposed based on current state-of-the-art methods. The observation requirements for these solutions, in terms of variables and spatial and temporal sampling needs, are therefore identified. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
15. Navigating through space and time: A methodological approach to quantify spatiotemporal connectivity using stream flow data as a case study.
- Author
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Cunillera‐Montcusí, David, Fernández‐Calero, José María, Pölsterl, Sebastian, Argelich, Roger, Fortuño, Pau, Cid, Núria, Bonada, Núria, and Cañedo‐Argüelles, Miguel
- Subjects
STREAMFLOW ,COMMUNITIES ,ECOLOGICAL disturbances ,ECOSYSTEM dynamics ,DATA loggers - Abstract
The growing interest in combining spatial and temporal patterns in nature has been fostered by the current availability of high‐frequency measurements. However, we still lack a methodological framework to process and interpret spatiotemporal datasets into meaningful values, adaptable to different time windows and/or responding to different spatial structures. Here, we developed and tested a framework to evaluate spatiotemporal connectivity using two new measures: the spatiotemporal connectivity (STcon) and the spatiotemporal connectivity matrix (STconmat).To obtain these measures, we consider a set of spatially connected sites within a temporally dynamic network. These measures are calculated from a spatiotemporal matrix where spatial and temporal connections across sites are captured. These connections respond to a determined network structure, assign different values to these connections and generate different scenarios from which we obtain the spatiotemporal connectivity. We developed these measures by using a dataset of stream flow state spanning a 513‐day period obtained from data loggers installed in seven temporary streams. These measures allowed us to characterise connectivity among stream reaches and relate spatiotemporal patterns with macroinvertebrate community structure and composition.Spatiotemporal connectivity differed within and among streams, with STcon and STconmat capturing different hydrological patterns. Macroinvertebrate richness and diversity were higher in more spatiotemporally connected sites. Community dissimilarity was related to STconmat showing that more spatiotemporally connected sites had similar communities for active and passive dispersers. Interestingly, both groups were related to spatiotemporal connectivity patterns for some of the analysed scenarios, highlighting the relevance of spatiotemporal connectivity in dynamic systems.As we exemplified, the proposed framework can help to disentangle and quantify spatiotemporal dynamics or be applied in the conservation of dynamic systems such as temporary streams. However, the current framework is not limited to the temporal and spatial features of temporary streams. It can be extended to other ecosystems by including different time windows and/or consider different network structures to assess spatiotemporal patterns. Such spatiotemporal measures are especially relevant in a context of global change, with the spatiotemporal dynamics of ecosystems being heavily disrupted by human activities. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
16. SEGMENTATION OF MULTIGRADATION IMAGES BASED ON SPATIAL CONNECTIVITY FEATURES.
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Timchenko, Leonid, Kokriatskaya, Natalia, Tverdomed, Volodymyr, Stetsenko, Oleksandr, Kaplun, Valentina, Kolesnytskyj, Oleg K., Reshetnik, Oleksandr, Smailova, Saule, and Zhunissova, Ulzhalgas
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IMAGE segmentation ,RADIO engineering ,INFORMATION technology ,ARTIFICIAL intelligence ,COMPUTER vision ,CITATION indexes - Published
- 2023
- Full Text
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17. Urban Informality Tactics Through the Layers of Socio-Spatial Connectivity
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Andri Yatmo, Yandi, Atmodiwirjo, Paramita, Marinic, Gregory, editor, and Meninato, Pablo, editor
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- 2022
- Full Text
- View/download PDF
18. Mobility patterns consideration of educational facilities distribution model formulation in Southeast Malang Regional development plan
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Respati Wikantiyoso, Tonny Suhartono, Pindo Tutuko, and Aditya Galih Sulaksono
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educational facilities distribution ,mobility patterns ,space syntax ,spatial connectivity ,Architecture ,NA1-9428 ,Architectural engineering. Structural engineering of buildings ,TH845-895 - Abstract
Regional disparities, and urban sprawl, will cause inequality in mobility between regions—one of the causes of the uneven distribution of educational facilities. The study of mobility patterns provides an overview of student movement patterns from and to school. The analysis is needed to determine the potential problems due to spatial disparities in the settlement Development Area. The research purpose; is (1) to obtain a model for determining the location and distribution of public schools based on mobility patterns in urban settlement development areas and (2) to obtain the model formulation for spatial planning distribution of educational facilities. This research uses a descriptive exploratory method with Space Syntax analysis. The research location was selected using the Classified Purposive Sampling method with an observation scale in the Development Area. The school zoning system has implications for equal distribution of education, reducing the mobility gap between regions, reducing congestion, air pollution, and dependence on motorized transportation. The study results of patterns of connectivity, accessibility, and mobility become a consideration for the placement of educational facilities in the Development Area. This study will improve the arrangement of spatial patterns and distribution of educational facilities based on studies of connectivity, regional accessibility, and student mobility.
- Published
- 2022
- Full Text
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19. SEGMENTATION OF MULTIGRADATION IMAGES BASED ON SPATIAL CONNECTIVITY FEATURES
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Leonid Timchenko, Natalia Kokriatskaya, Volodymyr Tverdomed, Oleksandr Stetsenko, Valentina Kaplun, Oleg K. Kolesnytskyj, Oleksandr Reshetnik, Saule Smailova, and Ulzhalgas Zhunissova
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image segmentation ,image processing ,halftone images ,spatial connectivity ,Environmental engineering ,TA170-171 ,Environmental sciences ,GE1-350 - Abstract
The article aims to study the multi-level segmentation process of images of arbitrary configuration and placement based on features of spatial connectivity. Existing image processing algorithms are analyzed, and their advantages and disadvantages are determined. A method of organizing the process of segmentation of multi-gradation halftone images is developed and an algorithm of actions according to the described method is given.
- Published
- 2023
- Full Text
- View/download PDF
20. A big data–model integration approach for predicting epizootics and population recovery in a keystone species.
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Barrile, Gabriel M., Augustine, David J., Porensky, Lauren M., Duchardt, Courtney J., Shoemaker, Kevin T., Hartway, Cynthia R., Derner, Justin D., Hunter, Elizabeth A., and Davidson, Ana D.
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KEYSTONE species ,MACHINE learning ,RANCHING ,NATURAL resources management ,PRAIRIE dogs ,ANIMAL populations ,FOREST reserves ,BEE colonies - Abstract
Infectious diseases pose a significant threat to global health and biodiversity. Yet, predicting the spatiotemporal dynamics of wildlife epizootics remains challenging. Disease outbreaks result from complex nonlinear interactions among a large collection of variables that rarely adhere to the assumptions of parametric regression modeling. We adopted a nonparametric machine learning approach to model wildlife epizootics and population recovery, using the disease system of colonial black‐tailed prairie dogs (BTPD, Cynomys ludovicianus) and sylvatic plague as an example. We synthesized colony data between 2001 and 2020 from eight USDA Forest Service National Grasslands across the range of BTPDs in central North America. We then modeled extinctions due to plague and colony recovery of BTPDs in relation to complex interactions among climate, topoedaphic variables, colony characteristics, and disease history. Extinctions due to plague occurred more frequently when BTPD colonies were spatially clustered, in closer proximity to colonies decimated by plague during the previous year, following cooler than average temperatures the previous summer, and when wetter winter/springs were preceded by drier summers/falls. Rigorous cross‐validations and spatial predictions indicated that our final models predicted plague outbreaks and colony recovery in BTPD with high accuracy (e.g., AUC generally >0.80). Thus, these spatially explicit models can reliably predict the spatial and temporal dynamics of wildlife epizootics and subsequent population recovery in a highly complex host–pathogen system. Our models can be used to support strategic management planning (e.g., plague mitigation) to optimize benefits of this keystone species to associated wildlife communities and ecosystem functioning. This optimization can reduce conflicts among different landowners and resource managers, as well as economic losses to the ranching industry. More broadly, our big data–model integration approach provides a general framework for spatially explicit forecasting of disease‐induced population fluctuations for use in natural resource management decision‐making. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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21. Resource predictability modulates spatial-use networks in an endangered scavenger species.
- Author
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Cerecedo-Iglesias, Catuxa, Bartumeus, Frederic, Cortés-Avizanda, Ainara, Pretus, Joan Ll., Hernández-Matías, Antonio, and Real, Joan
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ENDANGERED species ,LIVESTOCK carcasses ,WASTE minimization ,WILDLIFE conservation ,POPULATION viability analysis ,RARE birds ,CIRCULAR economy - Abstract
Background: Changes in human-induced resource availability can alter the behaviour of free-living species and affect their foraging strategies. The future European Landfill Waste Directive and Circular Economy Action Plan will reduce the number of predictable anthropogenic food subsidies (PAFS), above all, by closing landfills to preclude negative effects on human health. Obligate avian scavengers, the most threatened group of birds worldwide, are the most likely group of species that will be forced to change their behaviour and use of space in response to landfill site closures. Here, we examine the possible consequences of these management decisions on the foraging patterns of Egyptian vultures (Neophron percnopterus) in an expanding population in the Iberian Peninsula. Methods: We tracked 16 individuals in 2018–2021, including breeders and non-breeders, and, using a combination of spatial-use and spatial-network modelling, assessed landscape connectivity between key resources based on movement patterns. We then carried out simulations of future scenarios based on the loss of PAFS to predict likely changes in the movement patterns of both non-breeders and breeders. Results: Our results show that foraging strategies in non-breeders and breeders differ significantly: non-breeders performed more dispersal movements than breeding birds across a spatial-use network. Non-breeding and breeding networks were found to be vulnerable to the removal of central foraging areas containing landfill sites, a highly predictable resource, while perturbation analysis showed dissimilar foraging responses to the gradual reduction of other predictable resources. Under a context of the non-availability of landfills for breeders and non-breeders, vultures will increase their use of extensive livestock as a trophic resource. Conclusions: Future environmental policies should thus extend the areas used by scavengers in which livestock carcasses are allowed to remain in the wild, a strategy that will also mitigate the lack of food caused by any reduction in available waste if landfills close. In general, our results emphasize the capabilities of a spatial network approaches to address questions on movement ecology. They can be used to infer the behavioural response of animal species and, also demonstrate the importance of applying such approaches to endangered species conservation within a context of changing humanized scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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22. بررسی کیفیت نفوذپذیری ورودیها بر میزان حضور پذیری در بازار (نمونه موردی: بازار سنتی شیراز).
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علی اکبر حیدری, ملیحه تقی پور, and مریم باقری
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PUBLIC spaces ,PHYSICAL measurements ,RESEARCH questions ,GEOMETRIC shapes ,LITERARY form ,CONTENT analysis - Abstract
Introduction The quality of permeability is a physical indicator that is significant in the formation of a successful place, especially in the field of public spaces. On the other hand, given that this research considers the issue of attendance of a traditional bazaar, the quality of permeability at the edges, especially the entrances and the rows leading to them, can play a significant role here. The entrance of a space is the first place where many of its features are discovered. Accordingly, the issue of quality of permeability is considered in this research as an independent variable, and its role in people’s presence in the space of a traditional bazaar is examined as a dependent variable. This concept of permeability has been proposed in the existing literature in three forms: neighborhood quality, spatial continuity, and accessibility. Theoretical framework According to the existing literature, the factors affecting permeability, especially in connection with urban contexts, can be examined in three areas, as follows. - The quality of neighborhoods. The quality of neighborhoods in a spatial configuration means the functional compatibility of the uses that form that space so that the performance of one does not disturb or hinder that of another. - Spatial continuity. Spatial continuity means the formal and functional connection of spaces with each other so that the environment is perceived by an external observer in a unified manner. This concept can be analyzed in an urban environment using indicators such as integration and connectivity. - Accessibility. In the literature on architecture, the issue of accessibility can be examined in two areas: visual accessibility and physical accessibility. Visual accessibility means the ability to view a space from neighboring spaces. Physical access pertains to people’s ability to move within the space. Methodology The current research adopts a combination of the qualitative and quantitative methods in data analysis. In the data collection section, the methods of documentary study, direct field observation, and interview with businesses and bazaar users were used, and in the data analysis section, the content analysis method and the space syntax software were used. In regard to the edges (independent variable), the three indicators of access quality (including physical access and visual access), spatial continuity, and the quality of neighborhoods were measured separately for each of the entrances. In the analysis of the quality of visual access, indicators were used such as the visibility of the entrances, the variety of uses in the bazaar that can be viewed from the entrance areas, and the amount of details on the space that can be viewed from the entrances. In the measurement of physical access, the degrees of enclosure and isolation of entrances in the bazaar were analyzed. In relation to the quality of neighborhoods, indicators such as the diversity and density of neighborhoods and the degree of their compatibility and interdependence were examined. Results and discussion No research has been conducted on the issue of attendance of the bazaar and the effect of the quality of permeability thereon, hence the attempt to answer the research questions about how the quality of permeability affects people’s attendance of the bazaar. - How does visual access affect attendance in the bazaar? The more visible the details from inside the bazaar to the user through its inputs, the more widely people choose those inputs to penetrate the bazaar and, therefore, the greater the attendance of the bazaar. The results of this research demonstrated that the difference in level between the passage and the space inside the market and the increase in the visible surface due to the presence of linear geometries along the lines leading to the entrances raises the range of visibility before entry into the bazaar space. - How does physical access affect attendance in the bazaar? The first feature for people to identify about the entrances is their visibility from the surrounding roads. If people can see inside the space before entering it, they can choose whether they want to enter the space or not. The second factor effective on physical access to the bazaar is the users’ willingness to use different entrances. In some cases, this increases the attendance of the bazaar, and in others, it decreases people’s desire attend it. - How does the quality of the neighborhood affect attendance in the bazaar? The existence of diverse uses and their density in those respects provides the possibility of meeting a greater range of client needs, which ultimately increases their attendance. Moreover, because they complement each other, users increase related nearby users’ attendance. However, the necessary conditions concerning the quality of neighbors are compatible with one another. This means that when incompatible users are placed together, they prevent people from attending the space due to the nuisance that they cause, besides their negative effects on each other’s functions. - How does spatial continuity at the entrances of the bazaar cause attendance thereof? The degree of spatial continuity at the bazaar entrances can be evaluated using the two indices of integration and connectivity. The values of these two indicators are directly related to the geometric and spatial qualities of the inputs and the lines leading to them. Conclusion The most important results of the current research can be presented as follows. • The quality of access to bazaar inputs is considered as the most important factor affecting permeability, thereby increasing bazaar attendance. This quality can be examined in the form of the two concepts of visual access and physical access. • The quality of neighborhoods can increase attendance in the bazaar in the form of the compatibility of and dependence between the uses of different bazaar lines and their density and diversity. • Spatial continuity at the entrances and the rows leading to them in the form of their geometric and spatial features (increasing the widths of the entrance and the rows leading thereto, connecting the entrance with public open spaces and main passages, using linear geometry, reducing the depths of the rows, and integrating and connecting the lines leading to the entrance with other spaces) can increase bazaar permeability and therefore its attendance. [ABSTRACT FROM AUTHOR]
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- 2023
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23. An objective evaluation of emergency plan types using space syntax and users’ responses.
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Ullah, Ubaid, Amin, Mohsin, and Park Jae Seung
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EMERGENCY management ,HOSPITAL emergency services - Abstract
Emergency departments are the doorstep of any hospital and designed in different plan types due to a multiplicity of factors. As treatment follows a specific medical pattern according to established SOPs, therefore the spatial configuration needs to respond to that pattern. this paper objectively analyzed the three basic plan types of the emergency department for its spatial configuration using space syntax and users' responses. The results of this study demonstrate that the three basic plan types of emergency departments follow a consistence configurational pattern in their syntactic values despite different layout patterns. All three types exhibit not only a very similar space link ratios, integration, and difference factor (DF) but also the internal integration of the order clinical spaces in a consistence way. The results were cross-validated through users' responses for the required spatial pattern through closed-ended structured questionaries. The results of this study may provide a baseline for the objective evaluation of the emergency department in the future. [ABSTRACT FROM AUTHOR]
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- 2023
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24. SIN: Superpixel Interpolation Network
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Yuan, Qing, Lu, Songfeng, Huang, Yan, Sha, Wuxin, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Pham, Duc Nghia, editor, Theeramunkong, Thanaruk, editor, Governatori, Guido, editor, and Liu, Fenrong, editor
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- 2021
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25. Resilient Slum Upgrading in Indonesia. Improving Spatial Connections from Bottom and Top
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Carracedo García-Villalba, Oscar, Dahiya, Bharat, Series Editor, Kirby, Andrew, Editorial Board Member, Friedberg, Erhard, Editorial Board Member, Singh, Rana P. B., Editorial Board Member, Yu, Kongjian, Editorial Board Member, El Sioufi, Mohamed, Editorial Board Member, Campbell, Tim, Editorial Board Member, Hayashi, Yoshitsugu, Editorial Board Member, Bai, Xuemei, Editorial Board Member, Haase, Dagmar, Editorial Board Member, and Carracedo García-Villalba, Oscar, editor
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- 2021
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26. Characterizing US Spatial Connectivity and Implications for Geographical Disease Dynamics and Metapopulation Modeling: Longitudinal Observational Study.
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Pullano G, Alvarez-Zuzek LG, Colizza V, and Bansal S
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- Humans, United States epidemiology, Longitudinal Studies, COVID-19 epidemiology
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Background: Human mobility is expected to be a critical factor in the geographic diffusion of infectious diseases, and this assumption led to the implementation of social distancing policies during the early fight against the COVID-19 emergency in the United States. Yet, because of substantial data gaps in the past, what still eludes our understanding are the following questions: (1) How does mobility contribute to the spread of infection within the United States at local, regional, and national scales? (2) How do seasonality and shifts in behavior affect mobility over time? (3) At what geographic level is mobility homogeneous across the United States?, Objective: This study aimed to address the questions that are critical for developing accurate transmission models, predicting the spatial propagation of disease across scales, and understanding the optimal geographical and temporal scale for the implementation of control policies., Methods: We analyzed high-resolution mobility data from mobile app usage from SafeGraph Inc, mapping daily connectivity between the US counties to grasp spatial clustering and temporal stability. Integrating this into a spatially explicit transmission model, we replicated SARS-CoV-2's first wave invasion, assessing mobility's spatiotemporal impact on disease predictions., Results: Analysis from 2019 to 2021 showed that mobility patterns remained stable, except for a decline in April 2020 due to lockdowns, which reduced daily movements from 45 million to approximately 25 million nationwide. Despite this reduction, intercounty connectivity remained seasonally stable, largely unaffected during the early COVID-19 phase, with a median Spearman coefficient of 0.62 (SD 0.01) between daily connectivity and gravity networks., We identified 104 geographic clusters of US counties with strong internal mobility connectivity and weaker links to counties outside these clusters. These clusters were stable over time, largely overlapping state boundaries (normalized mutual information=0.82) and demonstrating high temporal stability (normalized mutual information=0.95). Our findings suggest that intercounty connectivity is relatively static and homogeneous at the substate level. Furthermore, while county-level, daily mobility data best captures disease invasion, static mobility data aggregated to the cluster level also effectively models spatial diffusion., Conclusions: Our work demonstrates that intercounty mobility was negligibly affected outside the lockdown period in April 2020, explaining the broad spatial distribution of COVID-19 outbreaks in the United States during the early phase of the pandemic. Such geographically dispersed outbreaks place a significant strain on national public health resources and necessitate complex metapopulation modeling approaches for predicting disease dynamics and control design. We thus inform the design of such metapopulation models to balance high disease predictability with low data requirements., (© Giulia Pullano, Lucila Gisele Alvarez-Zuzek, Vittoria Colizza, Shweta Bansal. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org).)
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- 2025
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27. Network topology mediates freshwater fish metacommunity response to loss of connectivity.
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Lee, Finnbar, Simon, Kevin S., and Perry, George L. W.
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FRESHWATER fishes ,SPECIES diversity ,TOPOLOGY ,PUBLIC spaces ,FUNCTIONAL connectivity ,FRESHWATER biodiversity ,REGIME change - Abstract
Changes in connectivity regimes affect patterns of diversity and species richness. In riverine ecosystems, factors that vary through space and time, such as flow, the presence of barriers to movement, and network topology determine connectivity, and in turn shape patterns of diversity and richness. While the effects of network topology and changes in spatiotemporal connectivity regimes on patterns of species richness have been studied in isolation, they have not been studied simultaneously. We used a discrete‐time logistic growth metacommunity model to analyze the role of spatial and temporal functional connectivity in determining patterns of local (patch level) species richness in freshwater fish metacommunities. Our modeling suggests that: (1) the effect of spatial loss of connectivity on local species richness is mediated by network topology and where richness is measured in the system and (2) increasing temporal autocorrelation in connectivity results in increasing temporal autocorrelation in patch occupancy. Spatial and temporal loss of connectivity is a ubiquitous issue for river ecosystems, making understanding and predicting its effects of fundamental importance to both improving theory and guiding river management. Our findings highlight the importance of network topology (and hence context dependency) in shaping metacommunity response to changing connectivity regimes. [ABSTRACT FROM AUTHOR]
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- 2022
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28. Network topology mediates freshwater fish metacommunity response to loss of connectivity
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Finnbar Lee, Kevin S. Simon, and George L. W. Perry
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dendritic ecological networks ,dispersal ,environmental autocorrelation ,freshwater fish ,spatial connectivity ,temporal connectivity ,Ecology ,QH540-549.5 - Abstract
Abstract Changes in connectivity regimes affect patterns of diversity and species richness. In riverine ecosystems, factors that vary through space and time, such as flow, the presence of barriers to movement, and network topology determine connectivity, and in turn shape patterns of diversity and richness. While the effects of network topology and changes in spatiotemporal connectivity regimes on patterns of species richness have been studied in isolation, they have not been studied simultaneously. We used a discrete‐time logistic growth metacommunity model to analyze the role of spatial and temporal functional connectivity in determining patterns of local (patch level) species richness in freshwater fish metacommunities. Our modeling suggests that: (1) the effect of spatial loss of connectivity on local species richness is mediated by network topology and where richness is measured in the system and (2) increasing temporal autocorrelation in connectivity results in increasing temporal autocorrelation in patch occupancy. Spatial and temporal loss of connectivity is a ubiquitous issue for river ecosystems, making understanding and predicting its effects of fundamental importance to both improving theory and guiding river management. Our findings highlight the importance of network topology (and hence context dependency) in shaping metacommunity response to changing connectivity regimes.
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- 2022
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29. Fit-for-Purpose Information for Offshore Wind Farming Applications—Part-I: Identification of Needs and Solutions
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Jun She, Anouk Blauw, Lauri Laakso, Baptiste Mourre, Johannes Schulz-Stellenfleth, and Henning Wehde
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spatial connectivity ,observation requirements for ocean renewable energy ,monitoring in land–sea continuum ,integrated monitoring-modeling ,multi-scale processes ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Oceanography ,GC1-1581 - Abstract
The rapid expansion of offshore wind farms (OWFs) in European seas is accompanied by many challenges, including efficient and safe operation and maintenance, environmental protection, and biodiversity conservation. Effective decision-making for industry and environmental agencies relies on timely, multi-disciplinary marine data to assess the current state and predict the future state of the marine system. Due to high connectivity in space (land–estuarial–coastal sea), socioeconomic (multi-sectoral and cross-board), and environmental and ecological processes in sea areas containing OWFs, marine observations should be fit for purpose in relation to multiple OWF applications. This study represents an effort to map the major observation requirements (Part-I), identify observation gaps, and recommend solutions to fill those gaps (Part-II) in order to address multi-dimension challenges for the OWF industry. In Part-I, six targeted areas are selected, including OWF operation and maintenance, protection of submarine cables, wake and lee effects, transport and security, contamination, and ecological impact assessments. For each application area, key information products are identified, and integrated modeling–monitoring solutions for generating the information products are proposed based on current state-of-the-art methods. The observation requirements for these solutions, in terms of variables and spatial and temporal sampling needs, are therefore identified.
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- 2023
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30. The effect of local habitat and spatial connectivity on urban seed predation
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Swedish Research Council, Gaytán, Álvaro [/0000-0001-9827-4664], Van Dijk, Laura J. A. [0000-0003-1015-8496], Faticov, Maria [0000-0001-8206-9332], Barr, Anna E. [0000-0001-6791-4534], Tack, Ayco J. M. [0000-0002-3550-1070], Gaytán, Álvaro, Van Dijk, Laura J. A., Faticov, Maria, Barr, Anna E., Tack, Ayco J. M., Swedish Research Council, Gaytán, Álvaro [/0000-0001-9827-4664], Van Dijk, Laura J. A. [0000-0003-1015-8496], Faticov, Maria [0000-0001-8206-9332], Barr, Anna E. [0000-0001-6791-4534], Tack, Ayco J. M. [0000-0002-3550-1070], Gaytán, Álvaro, Van Dijk, Laura J. A., Faticov, Maria, Barr, Anna E., and Tack, Ayco J. M.
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Premise During the last centuries, the area covered by urban landscapes is increasing all over the world. Urbanization can change local habitats and decrease connectivity among these habitats, with important consequences for species interactions. While several studies have found a major imprint of urbanization on plant–insect interactions, the effects of urbanization on seed predation remain largely unexplored. Methods We investigated the relative impact of sunlight exposure, leaf litter, and spatial connectivity on predation by moth and weevil larvae on acorns of the pedunculate oak across an urban landscape during 2018 and 2020. We also examined whether infestations by moths and weevils were independent of each other. Results While seed predation varied strongly among trees, seed predation was not related to differences in sunlight exposure, leaf litter, or spatial connectivity. Seed predation by moths and weevils was negatively correlated at the level of individual acorns in 2018, but positively correlated at the acorn and the tree level in 2020. Conclusions Our study sets the baseline expectation that urban seed predators are unaffected by differences in sunlight exposure, leaf litter, and spatial connectivity. Overall, our findings suggest that the impact of local and spatial factors on insects within an urban context may depend on the species guild. Understanding the impact of local and spatial factors on biodiversity, food web structure, and ecosystem functioning can provide valuable insights for urban planning and management strategies aimed at promoting urban insect diversity.
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- 2024
31. Integrating acoustic emission into a percolation model to evaluate crack distribution characteristics of heated granite subjected to rapid cooling
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Chunbo Zhou, Feng Gao, Chengzheng Cai, Zekai Wang, Wenqi Zheng, and Xianghe Gao
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Liquid nitrogen cooling ,Acoustic emission events ,Percolation model ,Spatial connectivity ,Crack distribution ,Physics ,QC1-999 - Abstract
To compare the distribution of cracks formed in the failure process of heated granite subjected to rapid cooling, compression tests (0–60 MPa) and acoustic emission (AE) monitoring were performed on heated granite (25, 200, and 400 °C) after water cooling and liquid nitrogen (LN2) cooling. Integrating AE events into the percolation model and counting the AE events with a cube covering method, the main AE events with the highest spatial connectivity were identified among the whole set of AE events. The count, density, and fractal dimension of the whole set of AE events and the main AE events were discussed to indirectly evaluate the crack distribution in the failure process. The results show that the most frequent, maximum, and minimum neighbor distances between AE events can be evaluated by the covering cubes with various lengths. The main AE events with the highest spatial connectivity should be characterized by short neighbor distances and most frequent neighbor distances. When the length of covering cubes is large enough to exceed the most frequent neighbor distances, the corresponding length is defined as the characteristic length. When the characteristic length is determined as the length of the covering cubes, the main AE events can be identified among the whole set of AE events. According to the distributions of all the AE events and the main AE events, LN2 cooling is proven to result in a more number, density, and complexity of cracks than water cooling, under high temperatures and high confining pressures.
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- 2022
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32. Deep connections: Divergence histories with gene flow in mesophotic Agaricia corals.
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Prata, Katharine E., Riginos, Cynthia, Gutenkunst, Ryan N., Latijnhouwers, Kelly R. W., Sánchez, Juan A., Englebert, Norbert, Hay, Kyra B., and Bongaerts, Pim
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GENE flow , *HYBRID zones , *CORALS , *SPECIES hybridization , *REEFS , *POPULATION genetics - Abstract
Largely understudied, mesophotic coral ecosystems lie below shallow reefs (at >30 m depth) and comprise ecologically distinct communities. Brooding reproductive modes appear to predominate among mesophotic‐specialist corals and may limit genetic connectivity among populations. Using reduced representation genomic sequencing, we assessed spatial population genetic structure at 50 m depth in an ecologically important mesophotic‐specialist species Agaricia grahamae, among locations in the Southern Caribbean. We also tested for hybridisation with the closely related (but depth‐generalist) species Agaricia lamarcki, within their sympatric depth zone (50 m). In contrast to our expectations, no spatial genetic structure was detected between the reefs of Curaçao and Bonaire (~40 km apart) within A. grahamae. However, cryptic taxa were discovered within both taxonomic species, with those in A. lamarcki (incompletely) partitioned by depth and those in A. grahamae occurring sympatrically (at the same depth). Hybrid analyses and demographic modelling identified contemporary and historical gene flow among cryptic taxa, both within and between A. grahamae and A. lamarcki. These results (1) indicate that spatial connectivity and subsequent replenishment may be possible between islands of moderate geographic distances for A. grahamae, an ecologically important mesophotic species, (2) that cryptic taxa occur in the mesophotic zone and environmental selection along shallow to mesophotic depth gradients may drive divergence in depth‐generalists such as A. lamarcki, and (3) highlight that gene flow links taxa within this relativity diverse Caribbean genus. [ABSTRACT FROM AUTHOR]
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- 2022
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33. Local hydrological conditions and spatial connectivity shape invertebrate communities after rewetting in temporary rivers.
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Pineda-Morante, David, Fernández-Calero, José María, Pölsterl, Sebastian, Cunillera-Montcusí, David, Bonada, Núria, and Cañedo-Argüelles, Miguel
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INVERTEBRATE communities , *AQUATIC invertebrates , *AQUATIC insects , *COMMUNITIES - Abstract
Temporary rivers (TRs) dominate global river networks and are increasing in occurrence and spatiotemporal extent. However, few studies have investigated the communities that establish after rewetting events (i.e. the end of the dry phase), when local hydrological conditions can shape the communities through species sorting, and the spatial connectivity of sites can also influence colonisation. Here, we analysed the relative importance of both local hydrological conditions and spatial connectivity on the invertebrate communities of seven not impacted Mediterranean TRs after rewetting. We quantified the frequency and duration of drying events and the time since flow resumed. We also quantified spatial connectivity based on each site's position in the river network (i.e. network connectivity) and the presence of nearby disconnected streams. Overall, we found that both hydrological conditions and network connectivity played a significant role in structuring aquatic invertebrate communities after rewetting. Taxonomic richness, functional richness and functional redundancy decreased with the frequency and duration of drying events and increased with time since the most recent rewetting. Network connectivity showed a significant unimodal relationship with taxonomic and functional metrics. In contrast, the presence of nearby disconnected streams was negatively related to functional richness and functional dispersion. Given that flow intermittence in Mediterranean areas is expected to intensify under future global change scenarios, our results can be helpful to guide future conservation and management actions. [ABSTRACT FROM AUTHOR]
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- 2022
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34. Multiperiod Dynamic Programming Algorithm for Optimizing a Nature Reserve.
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Lin, Chih-Wei, Hong, Yu, Tu, Weihao, and Liu, Jinfu
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Zoning adjustments are a key method of improving the conservation efficiency of a nature reserve. Existing studies typically consider the one-period programming method and ignore dynamic ecological changes during the programming of a nature reserve. In this study, a scientific method for nature reserve (NR) programming, namely the multiperiod dynamic programming (MDP) algorithm, is proposed. The MDP algorithm designs an NR over three periods and does so by using ecological suitability values for each grid area. Ecological suitability values for each period were determined based on existing data on rare aquatic animals with Maxent software and cellular automata (CA). CA were used to determine the actual protection effect and to adjust each period's ecological suitability values through comparisons with the sites' surroundings. The maximization of ecological suitability values was used as an objective function; these values were assumed to indicate protection benefits. The objective function of the MDP also includes grid perimeters and numerical minimization for spatial compactness. Moreover, we designed three MDP constraints for the dynamic programming, including base constraints, distinguishing constraints, and multiperiod constraints. In the base and distinguishing constraints, we require a grid square to be a core, buffer, or unselected square, and we require the core and buffer grids to be spatially connected. For the multiperiod constraints, we used virtual points to ensure spatial continuity in different periods while attaining high ecological suitability. Our main contributions are as follows: (1) the novel MDP algorithm combining ecological attributes and multiperiod dynamic planning to optimize NR planning; (2) the use of virtual points to avoid selecting invalid grids and to ensure spatial continuity with significant protection benefits; and (3) the definition of ecological suitability values and use of CA to simulate dynamic changes over the three periods. The results reveal that the MDP algorithm results in a reserve with greater protection benefits than current reserves with superior spatial distribution due to multiperiod programming. The proposed MDP algorithm is a novel method for the scientific optimization and adjustment of nature reserves. [ABSTRACT FROM AUTHOR]
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- 2022
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35. influence of abiotic and spatial variables on woody and herbaceous species abundances in a woodland–grassland system in the Eastern Terai of India.
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Das, Dhritiman, Banerjee, Subham, Lehmkuhl, John, Krishnaswamy, Jagdish, and John, Robert
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WOODY plants ,SPECIES distribution ,SAVANNAS ,HERBACEOUS plants ,PLANT species ,SPECIES ,SOIL topography ,ECOSYSTEMS - Abstract
The environmental factors that influence tree–grass abundances in tropical savanna and grasslands are not well understood, particularly for woodland–grassland mosaics in humid zones. We studied the effects of abiotic and spatial variables on woody and herbaceous species distributions in a Terai ecosystem of northeastern India. We evaluated the importance of climatic and non-climatic factors that maintain variable tree–grass ratios across the landscape, and also accounted for spatial connectivity and dispersal. We measured species abundances of woody and herbaceous plant species in 134 plots with each 30 m × 30 m in a 519 km
2 protected Terai habitat, and derived several climatic and non-climatic environmental factors. We constructed variables based on different models of spatial connectivity among sites, to test their influence on species abundances. We then used redundancy analyses and variation partitioning to quantify the importance of environmental variables and spatial structure on variation in tree–grass abundances. We found that environmental variables including rainfall, fire, water stress, topography and soil nutrients had statistically significant effects on species abundance and tree–grass ratios. Spatial structure was significant, and the best spatial model was an inverse distance-weighted model with linkage extending to 23.5 km, indicating weak dispersal limitation. About 21% of the variation in species abundance was explained by the selected environmental and spatial factors. The results indicate that dynamic plant communities in which spatial–temporal variation in environmental factors may drive stochasticity in species distribution and abundance, thus dominantly influencing on the vegetation mosaic. [ABSTRACT FROM AUTHOR]- Published
- 2022
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36. Seasonal hydrology influences energy channels in food webs of rivers in the lower Okavango Delta.
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Bokhutlo, Thethela, Keppeler, Friedrich W., and Winemiller, Kirk O.
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SEASONS ,CALORIC content of foods ,HYDROLOGY ,FOOD chains ,STABLE isotopes ,FISH populations ,ECOSYSTEMS - Abstract
Floodplain aquatic ecosystems experience temporal changes in basal production sources and inputs from allochthonous sources that influence energy flow. We analyzed stable isotope ratios of carbon (δ
13 C) and nitrogen (δ15 N) from 449 fish muscles representing 18 species to characterize energy pathways in two rivers of the lower Okavango Delta, Botswana. We sampled fish during wet and dry seasons and used mixing models to estimate proportions of major basal production sources assimilated by fishes. We estimated trophic position (TP) for each fish population and assessed the association between TP and the degree that fish biomass was supported by a single production source. During the wet season, fishes in the Boteti River assimilated material through food chains originating mainly from aquatic macrophytes. During the dry season, terrestrial C3 plants and terrestrial C4 grasses assumed greater importance. In the Boro River, terrestrial C3 plants were inferred to be an important production source supporting fishes during the wet season, with aquatic macrophytes becoming more important during the dry season. In both rivers and seasons, the degree of dependence on a single source was negatively related to TP, supporting the hypothesis that organisms positioned higher in the food web tend to be supported by multiple food chains and basal sources, whereas organisms lower in the food web may be supported by many or few food chains. We showed that consumers in river food webs shift foraging habits in response to seasonal patterns of connectivity and habitat availability, thus promoting long-term population and community stability. [ABSTRACT FROM AUTHOR]- Published
- 2021
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37. Spatial Connectivity and Temporal Dynamic Functional Network Connectivity of Musical Emotions Evoked by Dynamically Changing Tempo
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Ying Liu, Weili Lian, Xingcong Zhao, Qingting Tang, and Guangyuan Liu
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dFNC ,spatial connectivity ,decreasing tempo ,increasing tempo ,music-evoked emotion ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Music tempo is closely connected to listeners’ musical emotion and multifunctional neural activities. Music with increasing tempo evokes higher emotional responses and music with decreasing tempo enhances relaxation. However, the neural substrate of emotion evoked by dynamically changing tempo is still unclear. To investigate the spatial connectivity and temporal dynamic functional network connectivity (dFNC) of musical emotion evoked by dynamically changing tempo, we collected dynamic emotional ratings and conducted group independent component analysis (ICA), sliding time window correlations, and k-means clustering to assess the FNC of emotion evoked by music with decreasing tempo (180–65 bpm) and increasing tempo (60–180 bpm). Music with decreasing tempo (with more stable dynamic valences) evoked higher valence than increasing tempo both with stronger independent components (ICs) in the default mode network (DMN) and sensorimotor network (SMN). The dFNC analysis showed that with time-decreasing FNC across the whole brain, emotion evoked by decreasing music was associated with strong spatial connectivity within the DMN and SMN. Meanwhile, it was associated with strong FNC between the DMN–frontoparietal network (FPN) and DMN–cingulate-opercular network (CON). The paired t-test showed that music with a decreasing tempo evokes stronger activation of ICs within DMN and SMN than that with an increasing tempo, which indicated that faster music is more likely to enhance listeners’ emotions with multifunctional brain activities even when the tempo is slowing down. With increasing FNC across the whole brain, music with an increasing tempo was associated with strong connectivity within FPN; time-decreasing connectivity was found within CON, SMN, VIS, and between CON and SMN, which explained its unstable valence during the dynamic valence rating. Overall, the FNC can help uncover the spatial and temporal neural substrates of musical emotions evoked by dynamically changing tempi.
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- 2021
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38. How to assess the temporal dynamics of landscape connectivity in ever-changing landscapes: a literature review.
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Uroy, Léa, Alignier, Audrey, Mony, Cendrine, Foltête, Jean-Christophe, and Ernoult, Aude
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FRAGMENTED landscapes ,LANDSCAPES ,GRAPH theory ,TIME series analysis ,BIODIVERSITY ,HABITATS - Abstract
Context: Landscape connectivity plays a key role in determining the persistence of species inhabiting fragmented habitat patches. In dynamic landscapes, most studies measure connectivity at multiple time steps, but pay less attention to explicitly quantifying its temporal dynamics to gain insights into its role in biodiversity patterns, thereby enabling more effective operational outcomes. Objectives: This article aimed at making an overview of the existing methods for the assessment of the temporal dynamics of connectivity. By analysing their differences and possible applications, we aimed to highlight knowledge gap and future research directions. Methods: We conducted a systematic review of literature dealing with the assessment of the temporal dynamics of connectivity and obtained 32 studies. Results: We presented two main approaches based on graph theory and compared them from conceptual and operational perspectives. The first widely used approach, accounting only for the spatial dispersal of organisms, quantifies temporal changes in spatial connectivity. Based on two or multiple time steps in the time series, this approach enables assessment of the sense and magnitude of the temporal changes in spatial connectivity. The second recently developed approach quantifies spatio-temporal connectivity, thus accounting for both spatial and temporal dispersal. So far, this holistic assessment of spatio-temporal connectivity only covers two time steps. Conclusion: Existing methods for the assessment of the temporal dynamics of connectivity provide indicators to advance our understanding of biodiversity patterns, and to be able to implement measures to conserve and restore connectivity. We propose future directions to develop these methods. [ABSTRACT FROM AUTHOR]
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- 2021
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39. Spatial Connectivity and Temporal Dynamic Functional Network Connectivity of Musical Emotions Evoked by Dynamically Changing Tempo.
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Liu, Ying, Lian, Weili, Zhao, Xingcong, Tang, Qingting, and Liu, Guangyuan
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INDEPENDENT component analysis ,MUSICAL perception ,EMOTIONS ,K-means clustering ,MUSICALS ,DEFAULT (Finance) - Abstract
Music tempo is closely connected to listeners' musical emotion and multifunctional neural activities. Music with increasing tempo evokes higher emotional responses and music with decreasing tempo enhances relaxation. However, the neural substrate of emotion evoked by dynamically changing tempo is still unclear. To investigate the spatial connectivity and temporal dynamic functional network connectivity (dFNC) of musical emotion evoked by dynamically changing tempo, we collected dynamic emotional ratings and conducted group independent component analysis (ICA), sliding time window correlations, and k-means clustering to assess the FNC of emotion evoked by music with decreasing tempo (180–65 bpm) and increasing tempo (60–180 bpm). Music with decreasing tempo (with more stable dynamic valences) evoked higher valence than increasing tempo both with stronger independent components (ICs) in the default mode network (DMN) and sensorimotor network (SMN). The dFNC analysis showed that with time-decreasing FNC across the whole brain, emotion evoked by decreasing music was associated with strong spatial connectivity within the DMN and SMN. Meanwhile, it was associated with strong FNC between the DMN–frontoparietal network (FPN) and DMN–cingulate-opercular network (CON). The paired t -test showed that music with a decreasing tempo evokes stronger activation of ICs within DMN and SMN than that with an increasing tempo, which indicated that faster music is more likely to enhance listeners' emotions with multifunctional brain activities even when the tempo is slowing down. With increasing FNC across the whole brain, music with an increasing tempo was associated with strong connectivity within FPN; time-decreasing connectivity was found within CON, SMN, VIS, and between CON and SMN, which explained its unstable valence during the dynamic valence rating. Overall, the FNC can help uncover the spatial and temporal neural substrates of musical emotions evoked by dynamically changing tempi. [ABSTRACT FROM AUTHOR]
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- 2021
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40. Thermographic Data Analysis for Defect Detection by Imposing Spatial Connectivity and Sparsity Constraints in Principal Component Thermography.
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Wen, Ching-Mei, Sfarra, Stefano, Gargiulo, Gianfranco, and Yao, Yuan
- Abstract
Data analysis methods have been extensively used in active thermography for defect identification. Among them, principal component thermography (PCT) is popular for dimensionality reduction and feature extraction. PCT summarizes the thermal images with a small number of empirical orthogonal functions that better reflect the information of defects. However, PCT does not induce sparsity, which limits the interpretation of PCT results. Recently, sparse PCT (SPCT) has been proposed to provide more interpretable analysis results. However, SPCT does not consider the spatial connectivity between pixels, omitting the fact that a defective region is usually spatially connected. In this article, a novel thermographic data analysis method is proposed to overcome the shortcomings of the existing methods. The proposed method imposes both spatial connectivity and sparsity constraints in PCT. Finally, one case study on an ancient marquetry sample and another on a carbon fiber-reinforced polymer composite illustrate the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]
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- 2021
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41. Porous Gaps Activating the Urban Space.
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Al-Hinkawi, Wahda Shuker and Almodhafar, Shatha Saleem
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URBAN growth ,URBAN planning ,ECONOMIC development ,POROSITY ,SOCIAL bonds ,PUBLIC spaces - Abstract
Many urban parts in the city center of Baghdad suffer from urban decay resulting from the porous gaps generated by the urban forces affecting the fabric in different stages of growth as well as recession and unsuitable urban development processes. Gaps have arisen in contemporary trends in urban design as spatial and social separation, leading to the disintegration and the rupture of the fabric, followed by social and spatial disruption that negatively affects economic development in the place and limits the opportunities for upgrading and investment. While other studies have investigated gaps to relink and activate the place, this research defines a theoretical framework that explains the mechanisms of investing in porosity to address urban gaps and activate the urban space. Investment in these indicators can activate a part of the vital urban fabric in Baghdad negatively impacted by gaps in order to achieve economic development and create opportunities for local investment in the fabric. This research has found out the gaps in the proposed study area as well as the reasons for their emergence and has clarified the indicators that should be improved to activate the porosity in order to achieve spatial connectivity that enhances social connectivity. [ABSTRACT FROM AUTHOR]
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- 2021
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42. Larval and adult fish assemblages along the Northwest Passage: the shallow Kitikmeot and the ice-covered Parry Channel as potential barriers to dispersal
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Caroline Bouchard, Maxime Geoffroy, Mathieu LeBlanc, and Louis Fortier
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arctic cod ,polar cod ,fish larvae ,canadian arctic archipelago ,spatial connectivity ,Environmental sciences ,GE1-350 ,Environmental engineering ,TA170-171 - Abstract
Climate warming and sea ice decline are expected to increase fish population movements in the circumpolar Arctic, including across the Canadian Arctic Archipelago (CAA). Knowledge gaps on present distribution, habitat uses, barriers to dispersal, and population connectivity along the Northwest Passage (NWP) limit science-based management of fish in the North American Arctic. Pelagic trawl, bottom trawl, and ichthyoplankton net collections from the US Beaufort Sea to Baffin Bay between 2005 and 2017 are used to map fish distribution along the NWP and identify potential zoogeographic barriers. In the Kitikmeot (southern CAA), the combination of shallow depths, sub-zero temperatures and slow water circulation may represent a physical barrier reducing the dispersal of marine fish between western and eastern regions. In contrast, the Parry Channel (northern CAA) may exemplify a disappearing sea ice barrier as climate warming unfolds and allow new genetic exchanges.
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- 2018
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43. Topology-Based Analysis for Multimodal Atmospheric Data of Volcano Eruptions
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Kuhn, Alexander, Engelke, Wito, Flatken, Markus, Hege, Hans-Christian, Hotz, Ingrid, Hege, Hans-Christian, Series editor, Hoffman, David, Series editor, Johnson, Christopher R., Series editor, Polthier, Konrad, Series editor, Rumpf, Martin, Series editor, Carr, Hamish, editor, Garth, Christoph, editor, and Weinkauf, Tino, editor
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- 2017
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44. Estimation of the Spatial Connectivity of the Economic Activity of Russian Regions.
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Kolomak, E. A.
- Abstract
The article examines change in the effects of spatial connectivity of Russian regions' economic activity for 1997–2016. Quantitative estimates are obtained using spatial econometrics methods. Two specifications of the model are used: the spatial lag model and spatial error model. Relations between regions are modeled through spatial external effects, which are described in two ways: using a nearest neighbor matrix and an inverse distance matrix. The following hypotheses are tested: (1) a single macroeconomic policy and market integration stimulate growth in the spatial connectivity of economic activity; (2) Russia's western territories have closer spatial ties compared to the eastern; (3) imposition of sanctions against Russia stimulated the formation of new and strengthened existing internal ties, as well as the country's spatial connectivity. Estimates have shown that there are no distinct trends in the spatial connectivity of economic activity in Russia, nor were interregional interactions affected by international sanctions. Relations important for economic activity are supported mainly with neighboring regions. The cooperation that arises between regions is not deep spatially and fades rapidly with increasing distance. This is also confirmed by the fact that for European Russia, spatial relations are a more significant development factor than for eastern regions. [ABSTRACT FROM AUTHOR]
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- 2020
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45. Habitat patchiness, ecological connectivity and the uneven recovery of boreal stream ecosystems from an experimental drought.
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Truchy, Amélie, Sarremejane, Romain, Muotka, Timo, Mykrä, Heikki, Angeler, David G., Lehosmaa, Kaisa, Huusko, Ari, Johnson, Richard K., Sponseller, Ryan A., and McKie, Brendan G.
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- *
ALGAL communities , *NUTRIENT cycles , *DROUGHTS , *RIVER channels , *HABITATS , *ECOSYSTEMS , *MICROBIAL respiration - Abstract
Ongoing climate change is increasing the occurrence and intensity of drought episodes worldwide, including in boreal regions not previously regarded as drought prone, and where the impacts of drought remain poorly understood. Ecological connectivity is one factor that might influence community structure and ecosystem functioning post‐drought, by facilitating the recovery of sensitive species via dispersal at both local (e.g. a nearby habitat patch) and regional (from other systems within the same region) scales. In an outdoor mesocosm experiment, we investigated how impacts of drought on boreal stream ecosystems are altered by the spatial arrangement of local habitat patches within stream channels, and variation in ecological connectivity with a regional species pool. We measured basal ecosystem processes underlying carbon and nutrient cycling: (a) algal biomass accrual; (b) microbial respiration; and (c) decomposition of organic matter, and sampled communities of aquatic fungi and benthic invertebrates. An 8‐day drought event had strong impacts on both community structure and ecosystem functioning, including algal accrual, leaf decomposition and microbial respiration, with many of these impacts persisting even after water levels had been restored for 3.5 weeks. Enhanced connectivity with the regional species pool and increased aggregation of habitat patches also affected multiple response variables, especially those associated with microbes, and in some cases reduced the effects of drought to a small extent. This indicates that spatial processes might play a role in the resilience of communities and ecosystem functioning, given enough time. These effects were however insufficient to facilitate significant recovery in algal growth before seasonal dieback began in autumn. The limited resilience of ecosystem functioning in our experiment suggests that even short‐term droughts can have extended consequences for stream ecosystems in the world's vast boreal region, and especially on the ecosystem processes and services mediated by algal biofilms. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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46. Navigating through space and time: A methodological approach to quantify spatiotemporal connectivity using stream flow data as a case study
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European Commission, 0000-0001-8666-346X, 0000-0003-0095-1765, 0000-0002-9997-5523, 0000-0002-2983-3335, 0000-0003-3864-7451, Cunillera-Montcusí, David, Fernández-Calero, José María, Pölsterl, Sebastian, Argelich, Roger, Fortuño, Pau, Cid, Núria, Bonada, Núria, Cañedo-Argüelles, Miguel, European Commission, 0000-0001-8666-346X, 0000-0003-0095-1765, 0000-0002-9997-5523, 0000-0002-2983-3335, 0000-0003-3864-7451, Cunillera-Montcusí, David, Fernández-Calero, José María, Pölsterl, Sebastian, Argelich, Roger, Fortuño, Pau, Cid, Núria, Bonada, Núria, and Cañedo-Argüelles, Miguel
- Abstract
The growing interest in combining spatial and temporal patterns in nature has been fostered by the current availability of high-frequency measurements. However, we still lack a methodological framework to process and interpret spatiotemporal datasets into meaningful values, adaptable to different time windows and/or responding to different spatial structures. Here, we developed and tested a framework to evaluate spatiotemporal connectivity using two new measures: the spatiotemporal connectivity (STcon) and the spatiotemporal connectivity matrix (STconmat). To obtain these measures, we consider a set of spatially connected sites within a temporally dynamic network. These measures are calculated from a spatiotemporal matrix where spatial and temporal connections across sites are captured. These connections respond to a determined network structure, assign different values to these connections and generate different scenarios from which we obtain the spatiotemporal connectivity. We developed these measures by using a dataset of stream flow state spanning a 513-day period obtained from data loggers installed in seven temporary streams. These measures allowed us to characterise connectivity among stream reaches and relate spatiotemporal patterns with macroinvertebrate community structure and composition. Spatiotemporal connectivity differed within and among streams, with STcon and STconmat capturing different hydrological patterns. Macroinvertebrate richness and diversity were higher in more spatiotemporally connected sites. Community dissimilarity was related to STconmat showing that more spatiotemporally connected sites had similar communities for active and passive dispersers. Interestingly, both groups were related to spatiotemporal connectivity patterns for some of the analysed scenarios, highlighting the relevance of spatiotemporal connectivity in dynamic systems. As we exemplified, the proposed framework can help to disentangle and quantify spatiotemporal dynamics
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- 2023
47. Analyzing Spatial Heterogeneity of Housing Prices Using Large Datasets.
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Wu, Yangyi, Wei, Yehua Dennis, and Li, Han
- Abstract
As an obstacle to the hedonic model's reliability, housing submarkets have drawn plenty of scholarly attention because they lack an integrated and standardized classification framework and validation methods. By incorporating multiple spatial statistics and data mining techniques into a hybrid spatial data mining method, this study develops an innovative classification methodology that replaces spatial continuity with spatial connectivity. Employing Salt Lake County as the case, we identify 43 housing submarkets based on differentiation among structural differences, the complexity of urban space, and neighborhood characteristics. With the introduction of urban amenities into the validation framework, the comparison between the submarket-based model and non-submarket regression shows our classification not only enhances prediction accuracy but also achieves better theoretical comprehension of local housing markets. Besides contributing to an understanding of urban spatial heterogeneity, our study also provides a feasible spatial modeling method which is capable of processing a large dataset with more than 200,000 observations. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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48. Preliminary insights into the population characteristics and distribution of reef (Mobula alfredi) and oceanic (M. birostris) manta rays in French Polynesia.
- Author
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Carpentier, Alice S., Berthe, Cécile, Ender, Isabel, Jaine, Fabrice R. A., Mourier, Johann, Stevens, Guy, De Rosemont, Moeava, and Clua, Eric
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MOBULIDAE ,SCIENTIFIC expeditions ,SCIENTIFIC community ,RECORD collecting ,SPECIES distribution ,SCIENTISTS - Abstract
In French Polynesia, both currently recognized manta ray species, Mobula alfredi and M. birostris, are observed. Despite being an important cultural asset and generating significant economic benefits through manta ray watching tourism, published data on the ecology and threats to these species in the region are scarce. Based on an 18-year dataset of sighting records collected by citizen scientists and during two scientific expeditions, this study provides the first insights into the population characteristics and regional distribution of the two manta ray species in French Polynesia. A total of 1347 manta ray photographs (1337 for M. alfredi and 10 for M. birostris) were examined for the period January 2001–December 2017, with photo-identification techniques leading to the successful identification of 317 individual M. alfredi and 10 individual M. birostris throughout the Society, Tuamotu and Marquesas Islands. We provide the first confirmation of sympatric distribution of both species in the Society Islands. Our results highlight strong and long-term site fidelity of M. alfredi individuals to certain aggregation sites (> 9 years for 16 individuals) and reveal some degree of connectivity between populations, with 10 individuals recorded moving between islands located up to 50 km apart. Analysis of photographs of individuals bearing sub-lethal injuries (n = 68) suggests that M. alfredi are more likely to be injured at inhabited islands (Maupiti or Bora Bora; 75% of all injured individuals) than at uninhabited islands, with 75% of injuries related to boat propeller strikes and fishing gear entanglements. Our findings emphasize the need for further research to allow for a comprehensive evaluation of population structure, size and threats to manta rays in this region. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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49. A big data–model integration approach for predicting epizootics and population recovery in a keystone species
- Author
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Gabriel M. Barrile, David J. Augustine, Lauren M. Porensky, Courtney J. Duchardt, Kevin T. Shoemaker, Cynthia R. Hartway, Justin D. Derner, Elizabeth A. Hunter, and Ana D. Davidson
- Subjects
disease ,prairie dog ,Ecology ,Yersinia pestis ,western Great Plains ,population dynamics ,spatial connectivity ,climate ,random forest - Abstract
Infectious diseases pose a significant threat to global health and biodiversity. Yet, predicting the spatiotemporal dynamics of wildlife epizootics remains challenging. Disease outbreaks result from complex nonlinear interactions among a large collection of variables that rarely adhere to the assumptions of parametric regression modeling. We adopted a nonparametric machine learning approach to model wildlife epizootics and population recovery, using the disease system of colonial black-tailed prairie dogs (BTPD, Cynomys ludovicianus) and sylvatic plague as an example. We synthesized colony data between 2001 and 2020 from eight USDA Forest Service National Grasslands across the range of BTPDs in central North America. We then modeled extinctions due to plague and colony recovery of BTPDs in relation to complex interactions among climate, topoedaphic variables, colony characteristics, and disease history. Extinctions due to plague occurred more frequently when BTPD colonies were spatially clustered, in closer proximity to colonies decimated by plague during the previous year, following cooler than average temperatures the previous summer, and when wetter winter/springs were preceded by drier summers/falls. Rigorous cross-validations and spatial predictions indicated that our final models predicted plague outbreaks and colony recovery in BTPD with high accuracy (e.g., AUC generally > 0.80). Thus, these spatially explicit models can reliably predict the spatial and temporal dynamics of wildlife epizootics and subsequent population recovery in a highly complex host-pathogen system. Our models can be used to support strategic management planning (e.g., plague mitigation) to optimize benefits of this keystone species to associated wildlife communities and ecosystem functioning. This optimization can reduce conflicts among different landowners and resource managers, as well as economic losses to the ranching industry. More broadly, our big data-model integration approach provides a general framework for spatially explicit forecasting of disease-induced population fluctuations for use in natural resource management decision-making. Thunder Basin Research Initiative; National Institute of Food and Agriculture [2020-67019-31153] Published version We are grateful to Paul Stapp, Eddie Childers, Buck Cully, Jeff Abeglen, Kristin Philbrook, Janice Naylor, Erin Considine, Andy Chappell, Jennifer Avising, Ruben Mares, Gwyn McKee, Peter McDonald, Travis Livieri, Lynne Deibel, Jessica Alexander, Daniel Kinka, Kristy Bly, Nicole Rosmarino, Tara Stephens, and numerous other biologists and field technicians for their data collection and sharing of prairie dog colony boundaries and other associated data across the Great Plains region. We thank David Eads, David Pellatz, and two anonymous reviewers for providing comments that helped to greatly improve the manuscript. This work is part of the Thunder Basin Research Initiative. Funding was provided by the National Institute of Food and Agriculture (Award no.: 2020-67019-31153). Public domain – authored by a U.S. government employee
- Published
- 2023
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50. Landscape and habitat filters jointly drive richness and abundance of specialist plants in terrestrial habitat islands.
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Deák, Balázs, Valkó, Orsolya, Török, Péter, Kelemen, András, Bede, Ádám, Csathó, András István, and Tóthmérész, Béla
- Subjects
HABITATS ,BIODIVERSITY ,PLANT ecology ,SPECIES diversity ,PLANT species - Abstract
Context: Landscape and habitat filters are major drivers of biodiversity of small habitat islands by influencing dispersal and extinction events in plant metapopulations.Objectives: We assessed the effects of landscape and habitat filters on the species richness, abundance and trait composition of grassland specialist and generalist plants in small habitat islands. We studied traits related to functional spatial connectivity (dispersal ability by wind and animals) and temporal connectivity (clonality and seed bank persistence) using model selection.Methods: We sampled herbaceous plants, landscape (local and regional isolation) and habitat filters (inclination, woody encroachment and disturbance) in 82 grassland islands in Hungary.Results: Isolation decreased the abundance of good disperser specialist plants due to the lack of directional vectors transferring seeds between suitable habitat patches. Clonality was an effective strategy, but persistent seed bank did not support the survival of specialist plants in isolated habitats. Generalist plants were unaffected by landscape filters due to their wide habitat breadth and high propagule availability. Clonal specialist plants could cope with increasing woody encroachment due to their high resistance against environmental changes; however, they could not cope with intensive disturbance. Steep slopes providing environmental heterogeneity had an overall positive effect on species richness.Conclusions: Specialist plants were influenced by the interplay of landscape filters influencing their abundance and habitat filters affecting species richness. Landscape filtering by isolation influenced the abundance of specialist plants by regulating seed dispersal. Habitat filters sorted species that could establish and persist at a site by influencing microsite availability and quality. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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