1
|
Acuña-Alonso C, García-Ontiyuelo M, Barba-Barragáns D, Álvarez X. Development of a convolutional neural network to accurately detect land use and land cover. MethodsX 2024; 12:102719. [PMID: 38660033 PMCID: PMC11041907 DOI: 10.1016/j.mex.2024.102719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/13/2024] [Indexed: 04/26/2024] Open
Abstract
The detection and modeling of Land Use and Land Cover (LULC) play pivotal roles in natural resource management, environmental modeling and assessment, and ecological connectivity management. However, addressing LULCC detection and modeling constitutes a complex data-driven process. In the present study, a Convolutional Neural Network (CNN) is employed due to its great potential in image classification. The development of these tools applies the deep learning method. A methodology has been developed that classifies the set of land uses in a natural area of special protection. This study area covers the Sierra del Cando (Galicia, northwest Spain), considered by the European Union as a Site of Community Interest and integrated in the Natura 2000 Network. The results of the CNN model developed show an accuracy of 91 % on training dataset and 88 % on test dataset. In addition, the model was tested on images of the study area, both from Sentinel-2 and PNOA. Despite some confusion especially in the residential class due to the characteristics in this area, CNNs prove to be a powerful classification tool.•Classifications based on a CNN model•LULC are classified into 10 different classes•Training and test accuracy are 91 % and 88 %, respectively.
Collapse
Affiliation(s)
- Carolina Acuña-Alonso
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain
- Centro de Investigação e Tecnologias Agroambientais e Biológicas, Universidade de Trás-os-Montes e Alto Douro, Ap 1013, 5001-801, Vila Real, Portugal
| | - Mario García-Ontiyuelo
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain
| | - Diego Barba-Barragáns
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain
| | - Xana Álvarez
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain
| |
Collapse
|
2
|
García-Ontiyuelo M, Acuña-Alonso C, Valero E, Álvarez X. Geospatial mapping of carbon estimates for forested areas using the InVEST model and Sentinel-2: A case study in Galicia (NW Spain). Sci Total Environ 2024; 922:171297. [PMID: 38423322 DOI: 10.1016/j.scitotenv.2024.171297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 02/01/2024] [Accepted: 02/25/2024] [Indexed: 03/02/2024]
Abstract
CO2 emissions have increased exponentially in recent years, so measuring and quantifying carbon sequestration is a step towards sustainable forest management and combating climate change. The overall goal of this study is to develop an accurate model for estimating carbon storage and sequestration for forest areas of the Atlantic Biogeographic Region. Specifically, the modelling and field sampling are carried out in the municipality of Baiona (Galicia, NW Spain), which was selected as a representative biome of this region. The methodology consists of carrying out two object-based image analysis (OBIA) classifications in spring and autumn to observe possible stocks of seasonal differences. Two carbon storage and sequestration models are built up (model 1 and model 2): model 1 for forest areas only and model 2 including all other land cover in the study area. Sentinel-2 geospatial data for 2021, Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) tools and geographic information systems (GIS) are used. A Kappa index of 0.92 is obtained for both classifications, thus ruling out any notable seasonal differences in the images used. The results from both models indicate that it is land covers associated with forest uses which store the most carbon in the study area, accounting for >50 % more than the other land covers. It is concluded that the methodology and data used are very useful for quantifying ecosystem services, which will help the governance of the region by implementing measures to mitigate some of the effects of climate change and help to create silvicultural models for the sustainable management of the Atlantic Biogeographic Region.
Collapse
Affiliation(s)
- Mario García-Ontiyuelo
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain.
| | - Carolina Acuña-Alonso
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain; Centre for the Research and Technology of Agro-Environmental and Biological Sciences - CITAB, University of Trás-os-Montes and Alto Douro (UTAD), Ap. 1013, 5001-801 Vila Real, Portugal.
| | - Enrique Valero
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain.
| | - Xana Álvarez
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain.
| |
Collapse
|
3
|
Acuna-Alonso C, do Valle Junior RF, de Melo Silva MMAP, Pissarra TCT, de Melo MC, Valera CA, Sanches Fernandes LF, Pacheco FAL, Álvarez X. Sediment source fingerprints of natural processes and anthropogenic pressures: A contribution to manage the Paraopeba River basin impacted by the B1 tailings dam collapse. J Environ Manage 2024; 356:120590. [PMID: 38522281 DOI: 10.1016/j.jenvman.2024.120590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/11/2024] [Accepted: 03/10/2024] [Indexed: 03/26/2024]
Abstract
Understanding the origins of sediment transport in river systems is crucial for effective watershed management, especially after catastrophic events. This information is essential for the development of integrated strategies that guarantee water security in river basins. The present study aimed to investigate the rupture of the B1 tailings dam of the Córrego do Feijão mine, which drastically affected the Brumadinho region (Minas Gerais, Brazil). To address this issue, a confluence-based sediment fingerprinting approach was developed through the SedSAT model. Uncertainty was assessed through Monte Carlo simulations and Mean Absolute Error (MAE). Estimates of the overall average contributions of each tributary were quantified for each station and annually during the period 2019-2021. It was observed that the sampling point PT-09, closest to the dam breach, contributed to almost 80% of the Paraopeba River in 2019. Despite the dredging efforts, this percentage increased to 90% in 2020 due to the need to restore the highly degraded area. Additionally, the main tributaries contributing to sediment increase in the river are Manso River "TT-03" (almost 36%), associated with an area with a high percentage of urban land use, and Cedro stream "TT-07" (almost 71%), whose geology promotes erosion, leading to higher sediment concentration. Uncertainties arise from the limited number of available tracers, variations caused by dredging activities, and reduced data in 2020 due to the pandemic. Parameters such as land use, riparian vegetation degradation, downstream basin geology, and increased precipitation are key factors for successfully assessing tributary contributions to the Paraopeba River. The obtained results are promising for a preliminary analysis, allowing the quantification of key areas due to higher erosion and studying how this disaster affected the watershed. This information is crucial for improving decision-making, environmental governance, and the development of mitigating measures to ensure water security. This study is pioneering in evaluating this methodology in watersheds affected by environmental disasters, where restoration efforts are ongoing.
Collapse
Affiliation(s)
- Carolina Acuna-Alonso
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain; Inov4Agro/Centro de Investigação e Tecnologias Agroambientais e Biológicas, Universidade de Trás-os-Montes e Alto Douro, Ap 1013, 5001-801, Vila Real, Portugal.
| | - Renato Farias do Valle Junior
- Instituto Federal do Triângulo Mineiro, Campus Uberaba, Laboratório de Geoprossessamento, Uberaba, MG, 38064-790, Brazil.
| | | | - Teresa Cristina Tarlé Pissarra
- Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (UNESP), Via de Acesso Prof. Paulo Donato Castellane, s/n, Jaboticabal, SP, 14884-900, Brazil.
| | - Marília Carvalho de Melo
- Secretaria de Estado de Meio Ambiente e Desenvolvimento Sustentável, Cidade Administrativa do Estado de Minas Gerais, Rodovia João Paulo II, 4143, Bairro Serra Verde, Belo Horizonte, Minas Gerais, Brazil.
| | - Carlos Alberto Valera
- Coordenadoria Regional das Promotorias de Justiça do Meio Ambiente das Bacias dos Rios Paranaíba e Baixo Rio Grande, Rua Coronel Antônio Rios, 951, Uberaba, MG, 38061-150, Brazil.
| | - Luis Filipe Sanches Fernandes
- Inov4Agro/Centro de Investigação e Tecnologias Agroambientais e Biológicas, Universidade de Trás-os-Montes e Alto Douro, Ap 1013, 5001-801, Vila Real, Portugal.
| | - Fernando António Leal Pacheco
- Centro de Química de Vila Real, Universidade de Trás-os-Montes e Alto Douro, Ap 1013, 5001-801, Vila Real, Portugal.
| | - Xana Álvarez
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain.
| |
Collapse
|
4
|
Rivas-Fandiño P, Acuña-Alonso C, Novo A, Pacheco FAL, Álvarez X. Assessment of high spatial resolution satellite imagery for monitoring riparian vegetation: riverine management in the smallholding. Environ Monit Assess 2022; 195:81. [PMID: 36342553 PMCID: PMC9640423 DOI: 10.1007/s10661-022-10667-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Riverine habitats are essential ecotones that bridge aquatic and terrestrial ecosystems, providing multiple ecosystem services. This study analyses the potential use of high-resolution satellite imagery, provided by the WorldView-2 satellite, in order to assess its viability for monitoring riparian ecosystems. It is performed by calculating the riparian strip quality index (RSQI) and calibrating it with the riparian quality index (QBR). The methodology was implemented in the Umia River, which is characterised by elevated anthropogenic pressures (located in the northwest of Spain). The results obtained by the method have a 92% of veracity and a kappa coefficient of 0.88. The average quality value obtained for the RSQI index was 71.57, while the average value for the QBR was 55.88. This difference could be attributed to the fact that the former does not differ between autochthonous and non-autochthonous vegetation. The areas with more accurate mapping corresponded to stretches of vegetation with optimal cover (80-50%), with good connectivity with the adjacent forest ecosystem and few or no presence of invasive plants. The worst-scoring sites had the next characteristics: low connectivity (< 10%), low forest cover (< 10%) and a higher presence of invasive plants. The degradation of vegetation could be explained by the presence of agriculture and deficient land use rationing caused by the type of ownership of the study area. The application of this index through satellite images will facilitate the environmental governance of multiple ecosystems and in special riparian ecosystems, obtaining a quick and objective methodology, easily replicable in other basins.
Collapse
Affiliation(s)
- Paula Rivas-Fandiño
- Agroforestry Group, School of Forestry Engineering, University of Vigo, 36005 Pontevedra, Spain
| | - Carolina Acuña-Alonso
- Agroforestry Group, School of Forestry Engineering, University of Vigo, 36005 Pontevedra, Spain
| | - Ana Novo
- Geotech Group, Department of Natural Resources and Environmental Engineering, School of Mining Engineering, CINTECX, University of Vigo, 36310 Vigo, Spain
| | | | - Xana Álvarez
- Agroforestry Group, School of Forestry Engineering, University of Vigo, 36005 Pontevedra, Spain
| |
Collapse
|
5
|
Janeiro-Otero A, Álvarez X, Fernández Crespo C, Valero E, Dormann CF. Grey wolf feeding habits and their geographical variation in Northwest Spain. Food Webs 2022. [DOI: 10.1016/j.fooweb.2022.e00248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
6
|
Acuña-Alonso C, Álvarez X, Valero E, Pacheco FAL. Modelling of threats that affect Cyano-HABs in an eutrophicated reservoir: First phase towards water security and environmental governance in watersheds. Sci Total Environ 2022; 809:152155. [PMID: 34890658 DOI: 10.1016/j.scitotenv.2021.152155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/28/2021] [Accepted: 11/29/2021] [Indexed: 06/13/2023]
Abstract
Cyano-HABs are proliferating around the world due to anthropogenic nutrient enrichment of freshwater bodies. This study seeks to obtain a holistic vision over the various threats that affect the Cyano-HABs of Umia basin and especially of A Baxe reservoir (Galicia, NW Spain), through the method of Partial least squares path modelling (PLS-PM). The A Baxe reservoirs is a fundamental source of drinking water supply to surrounding dwellings. This study identifies and quantify the variables that increase contaminant concentration and decrease ecological integrity, as well as how this scenario evolved over various hydrologic years. In this regard, the PLS-PM equations will be robust and powerful tools to predict changes in eutrophication and ecological integrity, as response to measures implemented in the basin that can improve water quality. The dependent latent variables are "Eutrophication" (chlorophyl-a, Microcystis sp.) and "Ecological Integrity" (METI Bioindicator). The independent latent variables are "SWP", which represents surface water parameters (phosphorus, nitrogen and pH) and "Climatic Conditions" (temperature, precipitation). The PLS-PM results revealed that 51.0% of "Eutrophication" is predicted by the independent variables. The connections between latent variables are quantified through path coefficients (β). The "SWP" contributes by increasing "Eutrophication" (β = 0.235), the same occurring with the "Climatic Conditions" (β = -0.672). The variables "Eutrophication" (β = -0.217) and "SWP" (β = -0.483) lower the "Ecological Integrity". On the other hand, different trophic scenarios, adapted to the temperature increase predicted for the study area, were tested, and it was found that ecological integrity would improve by 46% if the oligotrophic state were reached. Therefore, it is recommended to prevent pollution by means of water control and governance plans, as well as corrective and preventive measures, which guarantee the water security of the river basins. Despite the complex mathematics behind the PLS-PM models, their user-friendly development and application through interactive graphical interfaces make them easily transposable to other eutrophic reservoirs, widening the readership of these studies focused on multiple-geosphere assessment of environmental impacts.
Collapse
Affiliation(s)
- Carolina Acuña-Alonso
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005 Pontevedra, Spain.
| | - Xana Álvarez
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005 Pontevedra, Spain.
| | - Enrique Valero
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005 Pontevedra, Spain.
| | - Fernando António Leal Pacheco
- Center of Chemistry of Vila Real, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
| |
Collapse
|
7
|
Saavedra MJ, Fernandes C, Teixeira A, Álvarez X, Varandas S. Multiresistant bacteria: Invisible enemies of freshwater mussels. Environ Pollut 2022; 295:118671. [PMID: 34902528 DOI: 10.1016/j.envpol.2021.118671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Freshwater mussels are among the most endangered groups of fauna anywhere in world. The indiscriminate use of antibiotics has led to the emergence of resistant strains. These antibiotic-resistant bacteria play a key role in increasing the risk allied with the use of surface water and in spread of resistance genes. Two endangered freshwater mussel species, Margaritifera margaritifera and Potomida littoralis, were sampled at 4 sampling sites along a 50 km stretch of River Tua. Water samples were taken at same sites. Of the total of 135 isolates, 64.44% (39.26% from water and 25.19% from mussels) were coliform bacteria. Site T1, with the lowest concentration of coliform bacteria, and site T2 were the only ones where M. margaritifera was found. No E. coli isolates were found in this species and the pattern between water and mussels was similar. P. littoralis, which was present at T3/T4 sites, is the one that faces the highest concentration of bacterial toxins, which are found in treated wastewater effluents and around population centers. Sites T3/T4 have the isolates (water and mussels) with the highest resistance pattern, mainly to β-lactams. Water and P. littoralis isolates (T3/T4) showed resistance to penicillins and their combination with clavulanic acid, and to cephalosporins, precisely to a fourth generation of cephalosporin antibiotics. The analysis provides important information on the risk to water systems, as well as the need to investigate possible management measures. It is suggested that future studies on the health status of freshwater bivalves should incorporate measures to indicate bacteriological water quality.
Collapse
Affiliation(s)
- Maria José Saavedra
- CITAB-Inov4Agro, Centre for the Research and Technology of Agro-Environmental and Biological Sciences- Institute for Innovation, Capacity Building and Sustainability of Agri-Food Production, University of Trás-os-Montes and Alto Douro, 5000-801, Vila Real, Portugal; CIIMAR/CIMAR, Interdisciplinary Center for Marine and Environmental Research, University of Porto, Terminal de Cruzeiros Do Porto de Leixões, 4450-208, Matosinhos, Portugal.
| | - Conceição Fernandes
- CIMO, Mountain Research Center, ESA-Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
| | - Amílcar Teixeira
- CIMO, Mountain Research Center, ESA-Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
| | - Xana Álvarez
- University of Vigo, Agroforestry Group, School of Forestry Engineering, 36005, Pontevedra, Spain.
| | - Simone Varandas
- CITAB-Inov4Agro, Centre for the Research and Technology of Agro-Environmental and Biological Sciences- Institute for Innovation, Capacity Building and Sustainability of Agri-Food Production, University of Trás-os-Montes and Alto Douro, 5000-801, Vila Real, Portugal; CIBIO/InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Campus Agrário de Vairão, Vairão, Portugal.
| |
Collapse
|
8
|
Pacheco FAL, de Melo MC, Pissarra TCT, Álvarez X, Martins LMDO, Fernandes ACP, Moura JP, Fernandes LFS. A groundwater security model based on hydraulic turnover times and flow compartments. MethodsX 2022; 9:101766. [PMID: 35800984 PMCID: PMC9253716 DOI: 10.1016/j.mex.2022.101766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/15/2022] [Indexed: 11/04/2022] Open
Abstract
Starting with a log-linear relationship between groundwater discharge per unit drainage area (Q/Ab), hydraulic turnover time (t) and aquifer mobile storage (z), this study builds a groundwater security method at catchment scale. The method embeds previously published approaches to calculate Q/Ab, t and z, and relies solely on stream flow discharges and watershed areas. The ability to build a method on a couple of variables is remarkable. The method recasts the calculated variables as aquifer security indicators (SQ, St and Sz), relating SQ with yield capacity, St with self-depuration capacity and Sz with resilience. Groundwater security is the weighted product of SQ, St and Sz. The method is validated with stream flow discharges and drainage areas concerning 294 hydrometric stations and their watersheds, located in continental Portugal. The results revealed a majority of moderately to highly secure watersheds, especially as regards St (> 62%), while 7–10% were classified as very highly secured in general (SQ-St-Sz). The least secured basins are located in the more arid regions of continental Portugal (Northeast and south regions), as expected. The method can be easily transposed to any other region worldwide, with the necessary adaptions to regional climate, geological and topographic settings. • Compile stream flow discharge data and organize them as natural logarithms and logarithmic variations as function of time, to estimate Q, t and z; • Recast the Q, t and z values as SQ, St and Sz ratings, respectively, using the appropriate reclassification scales, and estimate watershed security levels, namely average security or customized (weighted) securities that highlight the contributions of Q/Ab (watershed yield), t (aquifer's self-depuration capacity) or z (aquifer's resilience); • Use the results to draw illustrative diagrams and spatial distribution maps.
Collapse
|
9
|
Álvarez X, Jiménez A, Cancela Á, Valero E, Sánchez Á. Harvesting freshwater algae with tannins from the bark of forest species: Comparison of methods and pelletization of the biomass obtained. Chemosphere 2021; 268:129313. [PMID: 33359839 DOI: 10.1016/j.chemosphere.2020.129313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/04/2020] [Accepted: 12/12/2020] [Indexed: 06/12/2023]
Abstract
Toxic cyanobacteria growth rates have increased in recent decades due to climate change and human activities. Microalgae, with their ability to produce a large amount of biomass, are considered as a source of energy that can be used to produce biofuels. The aim of this study is to test four different microalgae harvesting methods (sedimentation, coagulation-flocculation, pH variation, and centrifugation) in order to find which is best suited to the A Baxe reservoir, which has been suffering from cyanobacterial blooms in recent years. Centrifugation proved the most efficient method (85.74%-1790 RCF), but it can induce cell rupture. Natural sedimentation and pH variation obtained similar results at 49.36% and 49.02% respectively. Although all four methods have advantages, our results reveal that coagulation-flocculation, using 10 mg/L of Pinus pinaster, results in a removal efficiency of 68.10%, making it the most suitable method, though with 20 mg/L the performance was lower (66.03%). To minimise environmental waste, the microalgae removed were then transformed into pellets to be used as biofuel, with a higher heating value (HHV) of 21,196.96 ± 1602.33 kJ/kg. The pellets obtained from the microalgae residue did not meet all the requirements for use as biofuels, but microalgae biomass could be mixed with other sources and therefore looks like a promising option for the future.
Collapse
Affiliation(s)
- Xana Álvarez
- Natural Resources and Environment Engineering Department, School of Forestry Engineering, University of Vigo, Campus A Xunqueira S/n., 36005 Pontevedra, Spain.
| | - Alejandro Jiménez
- School of Forestry Engineering, University of Vigo, Campus A Xunqueira S/n., 36005, Pontevedra, Spain.
| | - Ángeles Cancela
- Chemical Engineering Department, School of Forestry Engineering, University of Vigo, Campus A Xunqueira S/n., 36005, Pontevedra, Spain.
| | - Enrique Valero
- Natural Resources and Environment Engineering Department, School of Forestry Engineering, University of Vigo, Campus A Xunqueira S/n., 36005 Pontevedra, Spain.
| | - Ángel Sánchez
- Chemical Engineering Department, School of Industrial Engineering, University of Vigo, Campus Lagoas-Marcosende S/n, 36310, Vigo-Pontevedra, Spain.
| |
Collapse
|
10
|
Acuña-Alonso C, Fernandes ACP, Álvarez X, Valero E, Pacheco FAL, Varandas SDGP, Terêncio DPS, Fernandes LFS. Water security and watershed management assessed through the modelling of hydrology and ecological integrity: A study in the Galicia-Costa (NW Spain). Sci Total Environ 2021; 759:143905. [PMID: 33340864 DOI: 10.1016/j.scitotenv.2020.143905] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
Water management is a crucial tool for addressing the increasing uncertainties caused by climate change, biodiversity loss and the conditions of socioeconomic limits. The multiple factors affecting water resources need to be successfully managed to achieve optimal governance and thus move towards water security. This study seeks to obtain a holistic vision of the various threats that affect the ecological integrity of the basins that form the hydrological district of Galicia-Costa, through the method of partial least squares path modelling (PLS-PM). The data is analysed overall for the hydrological years from 2009 to 2015. The independent latent variables are "Anthropogenic" (comprising the percentage of water bodies with edges alongside artificial surfaces, the percentage connected to artificial land use patches, the edge density of artificial surfaces and population density) and "Nature" (edge density of forestry land uses, edge length of land water bodies alongside forested areas and the percentage of land occupied by the largest patch of forest). The dependent latent variables are "SWP", which represents surface water parameters (biological oxygen demand, chlorides, conductivity and dissolved iron) and "Ecological Integrity" (METI Bioindicator). The connections between latent variables are uantified through path coefficients (β). From an overall perspective, the PLS-PM results reveal that 69.0% of "SWP" is predicted by the independent variables (R2 = 0.690), "Anthropogenic" contributes by increasing SWP (β = 0.471), while "Nature" decreases the concentration of SWP (β = -0.523), which indicates the polluting parameters in the water. The variables "Anthropogenic" (β = -0.351) and "SWP" (β = -0.265) lower the quality of "Ecological Integrity". This variable must be managed through soil conservation measures for the benefit of water security. This study has been able to identify and quantify the variables that increase contaminant concentration and decrease ecological integrity, providing a promising methodology that facilitates protection and correction measures to guarantee water safety.
Collapse
Affiliation(s)
- Carolina Acuña-Alonso
- Forestry Engineering School, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain.
| | - António Carlos Pinheiro Fernandes
- Center for Research and Agro-environmental and Biological Technologies, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
| | - Xana Álvarez
- Forestry Engineering School, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain.
| | - Enrique Valero
- Forestry Engineering School, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain.
| | - Fernando António Leal Pacheco
- Center of Chemistry of Vila Real, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
| | - Simone Da Graça Pinto Varandas
- Center for Research and Agro-environmental and Biological Technologies, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
| | - Daniela Patrícia Salgado Terêncio
- Center of Chemistry of Vila Real, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal; Center for Research and Agro-environmental and Biological Technologies, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
| | - Luís Filipe Sanches Fernandes
- Center for Research and Agro-environmental and Biological Technologies, University of Trás-os-Montes e Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
| |
Collapse
|
11
|
Acuña-Alonso C, Álvarez X, Lorenzo O, Cancela Á, Valero E, Sánchez Á. Assessment of water quality in eutrophized water bodies through the application of indexes and toxicity. Sci Total Environ 2020; 728:138775. [PMID: 32339839 DOI: 10.1016/j.scitotenv.2020.138775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
It is essential to have tools that can be used to diagnose water resources. For this reason, this study sets out on the one hand to assess water quality in three reservoirs in Spain (Salas, A Baxe and Conchas) with Cyano-Habs problems through the application of water quality indexes: The National Sanitation Foundation Water Quality Index (NFSWQI), the General Quality Index (GQI), the Trophic State Index (TSI), and the Trophic Contamination Index (ICOTRO). On the other hand, it seeks to learn how parameters such as nitrogen and phosphorus influence the presence of cyanotoxin, specifically Microcystis aeruginosa. To that end, samples from the three reservoirs are cultured and physical-chemical parameters and the toxicity of the water are measured. The results show that Salas reservoir has the worst water quality rating (GQI is bad and NFSWQI medium), while As Conchas and A Baxe obtain very good figures for NFSWQI. This contrasts with the data obtained via the TSI of moderately eutrophic conditions for all three reservoirs, and hypereutrophic levels for As Conchas and A Baxe downstream. On the other hand, the toxicity analysis shows levels of 1.12 ± 0.06 μg/l microcystin-LR (MC-LR) for As Conchas, 0.64 ± 0.04 μg/l MC-LR for Salas, and 1.24 ± 0.05 μg/l MC-LR for A Baxe, of which 20% corresponds to free MC-LR. This study finds that nitrogen is the parameter that most favors the production of MC-LR. We conclude that the eutrophication indexes are more reliable when studying the presence of cyanobacteria. Furthermore, nitrogen and phosphorous are the most significant parameters in this regard. They are taken into account in the quality indices (GQI, NFSWI), but they are not sufficiently representative. It is recommended as a future line of research that water quality indices be adapted or designed to incorporate eutrophication levels and even water toxicity.
Collapse
Affiliation(s)
- Carolina Acuña-Alonso
- Department of Natural Resources Engineering and the Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Xana Álvarez
- Department of Natural Resources Engineering and the Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Olalla Lorenzo
- School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n, 36005, Pontevedra, Spain
| | - Ángeles Cancela
- Chemical Engineering Department, School of Forestry Engineering, University of Vigo, Campus Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Enrique Valero
- Department of Natural Resources Engineering and the Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Ángel Sánchez
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo, Pontevedra, Spain.
| |
Collapse
|
12
|
Acuña-Alonso C, Lorenzo O, Álvarez X, Cancela Á, Valero E, Sánchez Á. Influence of Microcystis sp. and freshwater algae on pH: Changes in their growth associated with sediment. Environ Pollut 2020; 263:114435. [PMID: 32283394 DOI: 10.1016/j.envpol.2020.114435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/05/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
Samples from two reservoirs with eutrophication problems, located in Pontevedra and Ourense (Northwestern Spain), were cultured, along with a third crop from a reservoir with no problems detected in Ourense (Northwestern Spain). The samples were grown under the same conditions (with an average temperature of 21 ± 2 °C, and a 3000 lux light intensity) in triplicate, and their growth, absorbance and pH were studied. High correlation values were obtained for pH and cellular growth (R2 ≥ 95%). The water from Salas showed the greatest microalgal growth (0.15 × 106 cells/ml to 31.70 × 106 cells/ml of Microcystis sp. for the last day of culturing) and the greatest increase in pH (5.72-9.02). In all the cultures studied here, the main species that reproduced was Microcystis sp., which can produce neurotoxins and hepatotoxins. In addition, water samples were cultured with sediments of their own reservoir and with others to observe their evolution. The sediments studied in this case were rich in biotites, which can lead phosphate to be a limiting factor for phytoplankton due to the formation and sedimentation of insoluble salts of ferric phosphate. In crops grown with sediments from the Salas reservoir, actinobacteria developed which can inhibit microalgal growth. The study of the growth of cyanobacteria and possible methods of inhibiting them directly concerns the quality of water and its ecosystems, avoiding pollution and impact on ecosystems.
Collapse
Affiliation(s)
- Carolina Acuña-Alonso
- Engineering Department of Natural Resources and Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Olalla Lorenzo
- School of Forestry Engineering, Campus A Xunqueira s/n, University of Vigo, 36005, Pontevedra, Spain.
| | - Xana Álvarez
- Engineering Department of Natural Resources and Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Ángeles Cancela
- Chemical Engineering Department, School of Forestry Engineering, University of Vigo, Campus CampusAXunqueira s/n., 36005, Pontevedra, Spain.
| | - Enrique Valero
- Engineering Department of Natural Resources and Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005, Pontevedra, Spain.
| | - Ángel Sánchez
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310, Vigo, Pontevedra, Spain.
| |
Collapse
|
13
|
Álvarez X, Cancela Á, Freitas V, Valero E, Sánchez Á, Acuña-Alonso C. Hydrothermal Carbonization and Pellet Production from Egeria densa and Lemna minor. Plants 2020; 9:plants9040425. [PMID: 32244324 PMCID: PMC7238187 DOI: 10.3390/plants9040425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 11/16/2022]
Abstract
Biofuels are seen as a potential option for mitigating the effects of fossil fuel use. On the other hand, nutrient pollution is accelerating eutrophication rates in rivers, lakes, and coastal waters. Harvesting aquatic plants to produce biofuels could mitigate this problem, though it is important to attack the problem at source, mainly as regards the contribution of nutrients. For the first time, solid biofuels were obtained in the forms of carbon and pellets from the aquatic plants Egeria densa, which is classed as an invasive plant under the Spanish Catalogue of Exotic Invasive Species, and Lemna minor, both of which can be found in the Umia River in north-west Spain. The essential oils and macro- and microelements present in both these plants were also extracted and analyzed. The higher heating values (HHVs) of the carbon products obtained ranged from 14.28 to 17.25 MJ/kg. The ash content ranged from 22.69% to 49.57%. The maximum yield obtained for biochar for Egeria densa at 200 °C was 66.89%. Temperature significantly affects solid hydrochar yield. The HHVs of the pellets obtained ranged from 11.38 to 13.49 MJ/kg. The use of these species to obtain biofuels through hydrothermal carbonization (HTC) and pellets is a novel and effective approach that will facilitate the removal of nutrients that cause eutrophication in the Umia River. The elements extracted show that harvesting these plants will help to remove excessive nutrients from the ecosystem.
Collapse
Affiliation(s)
- Xana Álvarez
- Department of Natural Resources Engineering and the Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005 Vigo, Pontevedra, Spain; (E.V.); (C.A.-A.)
- Correspondence: ; Tel.: +34-986-801959
| | - Ángeles Cancela
- Chemical Engineering Department, School of Forestry Engineering, Campus A Xunqueira s/n, University of Vigo, 36005 Vigo, Pontevedra, Spain;
| | - Vanesa Freitas
- School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005 Vigo, Pontevedra, Spain;
| | - Enrique Valero
- Department of Natural Resources Engineering and the Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005 Vigo, Pontevedra, Spain; (E.V.); (C.A.-A.)
| | - Ángel Sánchez
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo, Pontevedra, Spain;
| | - Carolina Acuña-Alonso
- Department of Natural Resources Engineering and the Environment, School of Forestry Engineering, University of Vigo, Campus A Xunqueira s/n., 36005 Vigo, Pontevedra, Spain; (E.V.); (C.A.-A.)
| |
Collapse
|
14
|
|
15
|
Álvarez X, Gómez-Rúa M, Vidal-Puga J. River flooding risk prevention: A cooperative game theory approach. J Environ Manage 2019; 248:109284. [PMID: 31362170 DOI: 10.1016/j.jenvman.2019.109284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 07/13/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Socio-economic development combined with changing hydrological factors represents a challenge for extending flood protection. In particular, land owners should be encouraged to use their land in a way that improves its water retention capacity. However, problems of fairness may arise because a landowner can benefit or lose out depending on the use of other lands. This paper sets out to study the possibility of applying game theory through a cooperative game to solve this problem. Specifically, we look for a sharing rule function to help the planners to distribute the total benefit among landowners, taking into account a principle of stability. We concentrate on enhancing upstream water retention and focus on the role played by forests as natural water retention features. This is a methodological contribution that analyzes land use management for flood retention. Land planners, governments and landowners could use cooperative games as a flood risk management tool. With this method, compensations and benefits could be established to raise awareness and encourage land owners to cooperate.
Collapse
Affiliation(s)
- Xana Álvarez
- Escola de Enxeñaría Forestal, Universidade de Vigo, Campus A Xunqueira, 36005, Pontevedra, Spain.
| | - María Gómez-Rúa
- Economics, Society and Territory (ECOSOT - ECOBAS), Facultade de Ciencias Económicas e Empresariais, Universidade de Vigo, Campus Lagoas-Marcosende, 36310, Vigo, Spain.
| | - Juan Vidal-Puga
- Economics, Society and Territory (ECOSOT - ECOBAS), Facultade de Ciencias Sociais e da Comunicación. Universidade de Vigo. Campus A Xunqueira, 36005, Pontevedra, Spain.
| |
Collapse
|
16
|
Álvarez X, Valero E, Cancela Á, Sánchez Á. Freshwater algae competition and correlation between their growth and microcystin production. Environ Sci Pollut Res Int 2016; 23:21577-21583. [PMID: 27518397 DOI: 10.1007/s11356-016-7410-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 08/04/2016] [Indexed: 06/06/2023]
Abstract
There are some different freshwater algae in Eutrophic reservoirs which bloom with specific environmental conditions, and some of them are cyanobacteria. In this investigation, we have cultivated microalgae present in natural water samples from a eutrophic reservoir. Variations in temperature and light were evaluated, as well as the competition among different green algae and cyanobacteria. There were three different freshwater algae growing together, Scenedesmus sp., Kirchneriella sp. and Microcystis aeruginosa, this cyanobacterium was the algae that reached the highest development and growth during the culture. While the algae grew, the concentration of toxin (microcystin-LR) increased until it reached the highest levels at 570 μg g-1. Blooms occurred at temperatures of 28 ± 1.5 °C and light cycles of longer hours of light than dark. This took place during the summer months, from June to September (in the study area). At temperatures below 18 °C, algae did not grow. Blooms were reproduced to a laboratory scale in different conditions in order to understand the development of freshwater algae, as well as to help decision-making about water supply from that reservoir.
Collapse
Affiliation(s)
- Xana Álvarez
- Engineering Department of Natural Resources and Environment, E.I. Forestal, University of Vigo, Campus A Xunqueira s/n, 36005, Pontevedra, Spain.
| | - Enrique Valero
- Engineering Department of Natural Resources and Environment, E.I. Forestal, University of Vigo, Campus A Xunqueira s/n, 36005, Pontevedra, Spain
| | - Ángeles Cancela
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310, Vigo, Pontevedra, Spain
| | - Ángel Sánchez
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310, Vigo, Pontevedra, Spain
| |
Collapse
|
17
|
Cancela Á, Sánchez Á, Álvarez X, Jiménez A, Ortiz L, Valero E, Varela P. Pellets valorization of waste biomass harvested by coagulation of freshwater algae. Bioresour Technol 2016; 204:152-156. [PMID: 26773958 DOI: 10.1016/j.biortech.2016.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 06/05/2023]
Abstract
There is a comparison of different coagulants: calcium chloride (20, 60, 120 and 180 mg/L); sodium alginate (10 and 20 mg/L) and tannins of Eucalyptus globulus bark (10 and 20 mg/L) in order to make the most of each method. The results show that 20 mg/L of tannin achieved a recovery efficiency of 95.35±1.16, sodium alginate 90.49±0.53 and 84.04±2.29 for calcium chloride. Taking into account the economic side of the coagulants, obtaining tannins is a profitable process. Bark is waste biomass obtained in the forestry process; therefore it does not involve extra costs. Finally, the feasibility of making pellets from harvested algae was studied, and the results suggest that waste biomass pellets may be used as fuel in boilers in a mixture <54% with other waste sources as Eucalyptus g. branches.
Collapse
Affiliation(s)
- Ángeles Cancela
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo-Pontevedra, Spain
| | - Ángel Sánchez
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo-Pontevedra, Spain
| | - Xana Álvarez
- Department of Natural Resources and Environment Engineering, E E. Forestal, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain.
| | - Alejandro Jiménez
- E E. Forestal, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain
| | - Luis Ortiz
- Department of Natural Resources and Environment Engineering, E E. Forestal, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain
| | - Enrique Valero
- Department of Natural Resources and Environment Engineering, E E. Forestal, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain
| | - Paloma Varela
- E E. Forestal, University of Vigo, Campus A Xunqueira s/n., 36005 Pontevedra, Spain
| |
Collapse
|
18
|
Valero E, Álvarez X, Cancela Á, Sánchez Á. Harvesting green algae from eutrophic reservoir by electroflocculation and post-use for biodiesel production. Bioresour Technol 2015; 187:255-262. [PMID: 25863202 DOI: 10.1016/j.biortech.2015.03.138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/27/2015] [Accepted: 03/29/2015] [Indexed: 06/04/2023]
Abstract
Each year there are more frequent blooms of green algae and cyanobacteria, representing a serious environmental problem of eutrophication. Electroflocculation (EF) was studied to harvest the algae which are present in reservoirs, as well as different factors which may influence on the effectiveness of the process: the voltage applied to the culture medium, run times, electrodes separation and natural sedimentation. Finally, the viability of its use to obtain biodiesel was studied by direct transesterification. The EF process carried out at 10V for 1min, with an electrode separation of 5.5cm and a height of 4cm in culture vessel, obtained a recovery efficiency greater than 95%, and octadecenoic and palmitic acids were obtained as the fatty acid methyl esters (FAMEs). EF is an effective method to harvest green algae during the blooms, obtaining the greatest amount of biomass for subsequent use as a source of biodiesel.
Collapse
Affiliation(s)
- Enrique Valero
- AF4 Research Group, Department of Natural Resources and Environment Engineering, Forestry Engineering College, University of Vigo, Campus A Xunqueira s/n, 36005 Pontevedra, Spain.
| | - Xana Álvarez
- AF4 Research Group, Department of Natural Resources and Environment Engineering, Forestry Engineering College, University of Vigo, Campus A Xunqueira s/n, 36005 Pontevedra, Spain.
| | - Ángeles Cancela
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo, Pontevedra, Spain.
| | - Ángel Sánchez
- Chemical Engineering Department, Industrial Engineering College, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo, Pontevedra, Spain.
| |
Collapse
|
19
|
Valero E, Picos J, Lagos L, Álvarez X. Corrigendum to: Road and traffic factors correlated to wildlife–vehicle collisions in Galicia (Spain). Wildl Res 2015. [DOI: 10.1071/wr14060_co] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Wildlife–vehicle collisions (WVC) are one of the major risk factors for the safety of drivers, as well as a great danger to wildlife that moves through the territory. In recent decades, given the growth of these accidents, some researches emerged to understand what are the main causes of this phenomenon and find the best solutions for implementation and try to solve this problem.
Aims
The aim of the present study was to analyse the road and traffic characteristics of road segments with a high occurrence of WVC in north-western Spain, specifically, the collisions with wild ungulates (roe deer and wild boar).
Methods
A nearest-neighbour analysis was used to analyse the spatial distribution of the WVC spots, and so as to identify these hotspots of accidents, we performed a hotspot analysis using the routine nearest-neighbour hierarchical cluster. Then, we calculated the WVC density of each road segment (KP). The existence of differences in the values of variables between high and low accident densities was analysed using a Mann–Whitney U-test for the continuous variables, and a ?2-test for the categorical ones. Then, multiple logistic regression analysis was used to identify which variables could predict the existence of KPs with a high density of WVC.
Key results
Our results showed that the daily traffic volume, the width of the road, the number of lanes and speed limit affect whether a particular road marker has a high or low density of WVC.
Conclusions
We conclude that high WVC is frequently characterised by wider lanes and shoulders, as well as gentler slopes, whereas in the sections with narrower roads and a shorter curvature radius, there are some conditions (low visibility and speed reduction) that reduce the probability of having an accident with ungulates. However, the speed at which it is possible to drive on a given road section is closely related to the occurrence of WVC.
Implications
These findings emphasise the importance of including mitigation measures in the decision-making when planning and designing infrastructure.
Collapse
|
20
|
Valero E, Picos J, Lagos L, Álvarez X. Road and traffic factors correlated to wildlife–vehicle collisions in Galicia (Spain). Wildl Res 2015. [DOI: 10.1071/wr14060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context Wildlife–vehicle collisions (WVC) are one of the major risk factors for the safety of drivers, as well as a great danger to wildlife that moves through the territory. In recent decades, given the growth of these accidents, some researches emerged to understand what are the main causes of this phenomenon and find the best solutions for implementation and try to solve this problem. Aims The aim of the present study was to analyse the road and traffic characteristics of road segments with a high occurrence of WVC in north-western Spain, specifically, the collisions with wild ungulates (roe deer and wild boar). Methods A nearest-neighbour analysis was used to analyse the spatial distribution of the WVC spots, and so as to identify these hotspots of accidents, we performed a hotspot analysis using the routine nearest-neighbour hierarchical cluster. Then, we calculated the WVC density of each road segment (KP). The existence of differences in the values of variables between high and low accident densities was analysed using a Mann–Whitney U-test for the continuous variables, and a χ2-test for the categorical ones. Then, multiple logistic regression analysis was used to identify which variables could predict the existence of KPs with a high density of WVC. Key results Our results showed that the daily traffic volume, the width of the road, the number of lanes and speed limit affect whether a particular road marker has a high or low density of WVC. Conclusions We conclude that high WVC is frequently characterised by wider lanes and shoulders, as well as gentler slopes, whereas in the sections with narrower roads and a shorter curvature radius, there are some conditions (low visibility and speed reduction) that reduce the probability of having an accident with ungulates. However, the speed at which it is possible to drive on a given road section is closely related to the occurrence of WVC. Implications These findings emphasise the importance of including mitigation measures in the decision-making when planning and designing infrastructure.
Collapse
|