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24 pages, 6012 KiB  
Article
Using Baited Remote Underwater Video Surveys (BRUVs) to Analyze the Structure of Predators in Guanahacabibes National Park, Cuba
by Dorka Cobián-Rojas, Jorge Angulo-Valdés, Pedro Pablo Chevalier-Monteagudo, Lázaro Valentín García-López, Susana Perera-Valderrama, Joán Irán Hernández-Albernas and Hansel Caballero-Aragón
Fishes 2025, 10(4), 169; https://doi.org/10.3390/fishes10040169 - 10 Apr 2025
Viewed by 1311
Abstract
The reef fish communities of the Guanahacabibes National Park have been studied for 20 years using various methodologies that have allowed us to understand aspects of their diversity and structure. However, due to gaps in information about the abundance and distribution of mesopredators [...] Read more.
The reef fish communities of the Guanahacabibes National Park have been studied for 20 years using various methodologies that have allowed us to understand aspects of their diversity and structure. However, due to gaps in information about the abundance and distribution of mesopredators (big fish and sharks), a new study was conducted in 2017 to determine their structure, explore the influence of different factors on their spatial variability, and evaluate their behavior. To achieve this, the Baited Remote Underwater Video Surveys (BRUVs) methodology was successfully applied, locating a single set of BRUVs at 90 sites distributed across 9 sectors of the park’s functional zoning. Variability in mesopredator metrics and their potential prey was assessed through a PERMANOVA analysis; a distance-based linear model (DISTLM) was used to explore the relationship between mesopredator abundance and biological, abiotic, and condition variables; and animal behavior was classified as incidental, cautious, or aggressive. A total of 64 fish species were identified, 7 of which were mesopredators, and 3 were sharks. An uneven distribution and abundance were observed among sectors, with the most abundant mesopredators being Carcharhinus perezi, Sphyraena barracuda, and Mycteroperca bonaci. Mesopredator abundance was more closely related to the condition of zone use and its regulations than to biological and abiotic variables. Sharks were more abundant in strictly protected areas, which coincided with relatively murky waters and stronger currents. More than 50% of the observed sharks displayed exploratory and aggressive behavior towards the bait basket. The analyzed metrics validate the effectiveness of the management of the protected area and suggest the presence of healthy and resilient mesopredator fish communities. Full article
(This article belongs to the Special Issue Movement Ecology and Conservation of Large Marine Fishes (and Sharks))
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14 pages, 3336 KiB  
Article
Ichthyoplankton Assemblages from the Coasts of Hamsilos Nature Park, Sinop, Southern Black Sea: Biodiversity, Abundance, and Relationships with Environmental Variables
by Orçin Uygun and Funda Üstün
Water 2024, 16(18), 2670; https://doi.org/10.3390/w16182670 - 19 Sep 2024
Viewed by 1152
Abstract
This study was conducted using monthly data collected between July 2015 and June 2016 in the marine area of Hamsilos Nature Park, located in Sinop, Southern Black Sea. The primary objectives were to determine the diversity of ichthyoplankton assemblages, examine seasonal variations, assess [...] Read more.
This study was conducted using monthly data collected between July 2015 and June 2016 in the marine area of Hamsilos Nature Park, located in Sinop, Southern Black Sea. The primary objectives were to determine the diversity of ichthyoplankton assemblages, examine seasonal variations, assess spatial differences between the inner and outer parts of Hamsilos Bay, and highlight the ecological relationships of the predominant species with environmental factors. The comprehensive collection during the study resulted in a mean abundance of 2217 eggs.10 m2 and 2743 larvae.10 m2, with 28 species belonging to 21 families identified. Specifically, Engraulis encrasicolus is the most abundant in spring and summer, Gaidropsarus mediterraneus is the most abundant in autumn, and Sprattus sprattus is the most abundant in winter. A temporal analysis revealed the highest abundances in August, September, and July, with the lowest in April, May, and February. Significant seasonal differences in abundance and diversity were detected. No spatial differences were found between the inner and outer areas of Hamsilos Bay. Small pelagic species dominated the ichthyoplankton community, while demersal species, though diverse, were less abundant. According to the results of the DistLM analysis, the structure of the ichthyoplankton community is influenced by temperature and salinity. During the study, the water temperature ranged from 8.35 °C in February to 25.50 °C in August, and the salinity varied from 17.67 psu in September to 19.04 psu in May. Full article
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20 pages, 2759 KiB  
Article
Excessive Eutrophication as a Chemical Barrier for Fish Fauna Dispersion: A Case Study in the Emblematic Tietê River (São Paulo, Brazil)
by Bruna Urbanski and Marcos Nogueira
Water 2024, 16(10), 1383; https://doi.org/10.3390/w16101383 - 13 May 2024
Cited by 1 | Viewed by 2253
Abstract
The Tietê River receives most of the effluents and diffuse wastes from the São Paulo metropolis (21.9 million inhabitants). The study aimed to assess the extent to which environmental changes affected the fish fauna. We compared, in rainy and dry seasons, three sites [...] Read more.
The Tietê River receives most of the effluents and diffuse wastes from the São Paulo metropolis (21.9 million inhabitants). The study aimed to assess the extent to which environmental changes affected the fish fauna. We compared, in rainy and dry seasons, three sites in Tietê and three in tributaries with much better water quality conditions. No physical barriers exist between the sites. Fish were sampled with gillnets (exposed overnight) and the assemblage’s ecological attributes calculated. Water depth, transparency, temperature, electrical conductivity, dissolved oxygen, turbidity, total dissolved solids, pH, redox potential, total phosphorus, total nitrogen, and chlorophyll were simultaneously determined. Low oxygen concentrations (near zero in the rainy period), and the opposite for nutrients and total solids, separated the predominantly hypereutrophic Tietê from the tributaries (PCA). Differences in the fish assemblages were also evidenced (nMDS), including a higher richness per sample in tributaries (11 to 14 spp.) compared to Tietê (3 to 4 spp.). Siluriformes with accessory breathing dominated in Tietê and the highly tolerant detritivorous Prochilodus lineatus (the main commercial fish) was the only species found in all sites. The species correlated positively with oxygen in the tributaries and with turbidity, redox potential, and nutrients in Tietê (DistLM) (rainy season). Recovery measures are urgently required. Full article
(This article belongs to the Special Issue Aquatic Ecosystems: Biodiversity and Conservation)
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28 pages, 3977 KiB  
Article
Annual Dynamics of a Layered Phytoplankton Structure in a Meromictic Lagoon Partially Isolated from the White Sea
by Irina G. Radchenko, Vasilisa A. Aksenova, Dmitry A. Voronov, Dmitry Viktorovich Rostanets and Elena Dmitrievna Krasnova
Diversity 2023, 15(9), 1009; https://doi.org/10.3390/d15091009 - 11 Sep 2023
Cited by 3 | Viewed by 1582
Abstract
In a saline semi-isolated lagoon on Cape Zeleny (White Sea), the annual dynamics of the vertical hydrological structure and the seasonal dynamics of phytoplankton were traced. Species composition, vertical distribution, abundance, nutrition type, and biomass were analyzed. In total, 293 species and supraspecific [...] Read more.
In a saline semi-isolated lagoon on Cape Zeleny (White Sea), the annual dynamics of the vertical hydrological structure and the seasonal dynamics of phytoplankton were traced. Species composition, vertical distribution, abundance, nutrition type, and biomass were analyzed. In total, 293 species and supraspecific taxa of algae and cyanobacteria were found. Most of the identified species are marine, and 38 species are freshwater. Taxonomic composition changed in the lagoon throughout the year. Dinoflagellates dominated in winter and early June; unidentified cocci and flagellates in July; diatoms, dinoflagellates, and unidentified cells in August; dinoflagellates in September; and unidentified cocci and flagellates in October–November. The abundance of algae also changed in the lagoon throughout the year. The integrated biomass in the water column varied from 0.01 g C/m2 in January to 0.78 g C/m2 in early September. According to the environmental parameters, the water column of the lagoon was subdivided into several zones with different environmental conditions and corresponding phytoplankton communities. The similarity between the communities of different horizons was 32–46% in summer and 7% in winter. The chemocline layer was the most populous. It contained a maximum of phytoplankton biomass, 1–2 orders of magnitude higher than that in the overlying horizons. Despite the connection to the sea, the phytoplankton structure in the surface water layer in the lagoon and in the sea differed significantly in composition, quantitative parameters, and seasonal dynamics. The similarity between the communities never exceeded 50%. In terms of biomass dynamics, the lagoon lagged behind the sea until mid-summer, but, starting from August, it outnumbered it, and the phytoplankton development in the lagoon lasted longer, until late autumn. According to sequential tests DistLM, the phytoplankton structure and dynamics in the lagoon and in the sea were related to the daylength, water salinity, oxygen content, and pH by 24.5%. At the same time, the PhP structure did not depend on water temperature, underwater illuminance, or depth. Oxygen content and pH were defined by PhP activity. Salinity serves as a vector of the vertical sequence of ecological niches. The day length seems to be the crucial factor of the seasonal PhP dynamics in the semi-isolated coastal stratified lakes and lagoons. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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20 pages, 3294 KiB  
Article
Polychaete Diversity and Functional Trait Composition in Subtropical Mangrove Ecosystems
by Mohadeseh Miri, Jafar Seyfabadi, Mehdi Ghodrati Shojaei, Hassan Rahimian and Mohammad Valipour
Diversity 2023, 15(9), 998; https://doi.org/10.3390/d15090998 - 7 Sep 2023
Cited by 9 | Viewed by 3055
Abstract
Polychaetes play a vital role in the structure and functioning of benthic communities in mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of polychaete assemblages across different habitats in the mangrove ecosystems along the coast of the Persian Gulf and [...] Read more.
Polychaetes play a vital role in the structure and functioning of benthic communities in mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of polychaete assemblages across different habitats in the mangrove ecosystems along the coast of the Persian Gulf and Gulf of Oman is limited. In this study, we investigated the species and trait composition of polychaetes and environmental variables, in vegetated and mudflat habitats of three subtropical mangroves. The results showed that Neanthes glandicincta was widely distributed across all regions and habitats. The three-factor ANOVA showed that the abundance and taxonomic diversity of polychaetes differed significantly between two habitats and three mangrove ecosystems. The abundance of polychaetes was observed to be higher in mud habitats than in vegetated habitats. There was a significant difference in species and trait composition between different regions and habitats. Vegetated habitats had higher proportions of crawler predatory species that are longer lived (3–5 years), with larger body size (80–100 mm), and are upward conveyors, whereas mudflat habitats had higher proportions of mobile (burrower) omnivore species that are moderately lived (1–3 years), with larger body size (>100 mm), and are biodiffusers. The three-factor ANOVA showed a significant difference in the community weighted mean (CWM) index between two habitats and three mangrove ecosystems. Thus, the species and trait composition of polychaetes depend on the structural complexity of their respective habitats. The DistLM analysis showed that total organic carbon content of the sediment was the main predictor variable influencing species composition, while silt/clay content and salinity were the main predictor variables influencing the traits’ composition. The results showed how the composition of traits and the structure of polychaete communities change in mangrove ecosystems, which can be used for future studies on conservation strategies for mangrove ecosystems throughout the world. Full article
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20 pages, 5801 KiB  
Article
Deep-Dwelling Populations of Mediterranean Corallium rubrum and Eunicella cavolini: Distribution, Demography, and Co-Occurrence
by Laura Carugati, Davide Moccia, Lorenzo Bramanti, Rita Cannas, Maria Cristina Follesa, Susanna Salvadori and Alessandro Cau
Biology 2022, 11(2), 333; https://doi.org/10.3390/biology11020333 - 20 Feb 2022
Cited by 13 | Viewed by 3311
Abstract
Corallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in the deep rocky habitats of the Mediterranean Sea with a high hydrodynamic and moderate eutrophication. Their spatial distribution and demography in the deep sea are mainly affected by temperature and [...] Read more.
Corallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in the deep rocky habitats of the Mediterranean Sea with a high hydrodynamic and moderate eutrophication. Their spatial distribution and demography in the deep sea are mainly affected by temperature and direct and indirect anthropogenic activities; however, knowledge of the factors that potentially influence their co-existence is scarce. This paper provides novel data on the distribution and demography of these two species, at depths between 50 and 290 m in the Western Mediterranean Sea, providing insights on their co-occurrence. Both species exhibited the highest population density at deeper sites (>150 m), showing an inverse size–density relation. Density values ranged from 0.03 colonies m−2 to 32 and 80 col. m−2 for yellow gorgonian and red coral, respectively. The two species co-occurred in 13% of the total frames examined, mostly dwelling between 120 and 160 m depth. Distance-based linear modeling (DistLM) emphasized that when co-occurring the variability of the two species’ densities were significantly driven by the density—rather than the morphology (i.e., height)—of the other species. We stress the need for further studies to elucidate the possible mutual effects of suspension feeders and to test the role of different environmental factors potentially influencing inter-specific relationships. Full article
(This article belongs to the Special Issue Conservation of Marine Ecosystems: Selected Papers from MetroSea 2021)
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11 pages, 1054 KiB  
Article
Diversity and Distribution of Sabellida (Annelida) under Protection Regimes
by Luigi Musco, Margherita Licciano and Adriana Giangrande
Water 2021, 13(11), 1491; https://doi.org/10.3390/w13111491 - 26 May 2021
Cited by 4 | Viewed by 2890
Abstract
Sabellida are widespread, diverse and abundant in marine benthic habitats. Their distribution patterns on hard-bottom substrates are poorly studied so far. Little is known about the factors influencing their distribution, including the protection regimes that are known to affect assemblage diversity. We analyzed [...] Read more.
Sabellida are widespread, diverse and abundant in marine benthic habitats. Their distribution patterns on hard-bottom substrates are poorly studied so far. Little is known about the factors influencing their distribution, including the protection regimes that are known to affect assemblage diversity. We analyzed hard-bottom Sabellida at 1.5 and 5 m depths at the Torre Guaceto Marine Protected Area (MPA) (SE Italy) to describe diversity and distribution patterns, and to identify potential factors influencing their distribution. The Sabellida diversity varied significantly among stations and was higher at 5 m depth. No relation with the protection regime was found. Among environmental variables, only sedimentation appeared related, suggesting that local trophic features might have influenced the observed pattern. Among habitat formers, only the macroalga Halimeda tuna significantly explained part of the observed variation, probably due to its role as a basibiont for some Sabellida taxa. Other predictor variables of Sabellida distribution were the abundances of some invertebrate taxa, especially Syllidae and some filter feeders such as Sabellariida and Cirripedia, probably due to shared ecological requirements, rather than a direct effect on Sabellida distribution. The relation with the Syllidae remains obscure so far, albeit some kind of interaction (including predator/prey interactions) between these two taxa cannot be excluded. Sabellida should be taken into account when analyzing patterns of biodiversity of hard-bottom environments. Full article
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17 pages, 4253 KiB  
Article
Spatial Patterns of Macrozoobenthos Assemblages in a Sentinel Coastal Lagoon: Biodiversity and Environmental Drivers
by Soilam Boutoumit, Oussama Bououarour, Reda El Kamcha, Pierre Pouzet, Bendahhou Zourarah, Abdelaziz Benhoussa, Mohamed Maanan and Hocein Bazairi
J. Mar. Sci. Eng. 2021, 9(5), 461; https://doi.org/10.3390/jmse9050461 - 23 Apr 2021
Cited by 10 | Viewed by 4257
Abstract
This study presents an assessment of the diversity and spatial distribution of benthic macrofauna communities along the Moulay Bousselham lagoon and discusses the environmental factors contributing to observed patterns. In the autumn of 2018, 68 stations were sampled with three replicates per station [...] Read more.
This study presents an assessment of the diversity and spatial distribution of benthic macrofauna communities along the Moulay Bousselham lagoon and discusses the environmental factors contributing to observed patterns. In the autumn of 2018, 68 stations were sampled with three replicates per station in subtidal and intertidal areas. Environmental conditions showed that the range of water temperature was from 25.0 °C to 12.3 °C, the salinity varied between 38.7 and 3.7, while the average of pH values fluctuated between 7.3 and 8.0. In vegetated habitats, biomass values of the seagrass Zostera noltei Hornemann ranged between 31.7 gDW/m² and 170.2 gDW/m² while the biomass of the seagrass Ruppia cirrhosa (Petagna) Grande between 54.2 gDW/m² and 84.7 gDW/m². Sediment analyses showed that the lagoon is mainly composed of sandy and silty sediments. We recorded 37,165 individuals of macrofauna distributed in 63 taxa belonging to 50 families, with a mean abundance value of 4582.8 ind/m² and biomass average of 22.2 g/m². Distance-based linear modeling analysis (DISTLM) identified sediment characteristics, water parameters and habitat type (biomass of Z. noltei) as the major environmental drivers influencing macrozoobenthos patterns. Our results clearly revealed that the hydrographic regime (marine and terrestrial freshwater), sediment distribution and characteristics and the type of habitat (vegetated vs. unvegetated substrate) are the key factors determining the species composition and patterns of macrozoobenthos assemblages. Full article
(This article belongs to the Special Issue Benthic Species and Habitats)
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18 pages, 4243 KiB  
Article
Influence of Intensive Agriculture on Benthic Macroinvertebrate Assemblages and Water Quality in the Aconcagua River Basin (Central Chile)
by Pablo Fierro, Claudio Valdovinos, Carlos Lara and Gonzalo S. Saldías
Water 2021, 13(4), 492; https://doi.org/10.3390/w13040492 - 14 Feb 2021
Cited by 19 | Viewed by 4771
Abstract
This study assessed natural variation in the macroinvertebrate assemblages (MIB) and water quality in one of the main basins with the largest agricultural activities in Chile (Aconcagua River Basin). We sampled throughout the annual cycle; nine sampling sites were established along the basin, [...] Read more.
This study assessed natural variation in the macroinvertebrate assemblages (MIB) and water quality in one of the main basins with the largest agricultural activities in Chile (Aconcagua River Basin). We sampled throughout the annual cycle; nine sampling sites were established along the basin, classifying according to agricultural area coverage as least-disturbed, intermediate, and most-disturbed. We collected 56 macroinvertebrate taxa throughout the entire study area. Multivariate analysis shows significant differences among the three disturbance categories in different seasons, both water quality variables and the MIB structure. Distance-based linear model (DistLM) analysis for all seasons explained more than 95.9% of the macroinvertebrate assemblages, being significantly explained by chemical oxygen demand, pH, total coliforms, nitrites, elevation, and water temperature. ANOVA test revealed significant differences in the proportion of noninsect individuals, macroinvertebrates density, and the number of taxa among the three disturbance categories (p < 0.05). In general, water temperature, conductivity, chemical oxygen demand, ammonium, nitrites, and nitrates increased their values downstream in the basin. Our results indicate that the elevation gradient and increment in agricultural land use in the basin had a strong influence on water quality and MIB. A better understanding of these ecosystems could help conservation and integrated watershed management. Full article
(This article belongs to the Special Issue Impact of Land-Use Changes on Surface Hydrology and Water Quality)
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19 pages, 3238 KiB  
Article
Distribution of Toxic Cyanobacteria in Volcanic Lakes of the Azores Islands
by Rita Cordeiro, Rúben Luz, Joana Vilaverde, Vitor Vasconcelos, Amélia Fonseca and Vítor Gonçalves
Water 2020, 12(12), 3385; https://doi.org/10.3390/w12123385 - 2 Dec 2020
Cited by 14 | Viewed by 4158
Abstract
Eutrophication and global climate change gather advantageous conditions for cyanobacteria proliferation leading to bloom formation and cyanotoxin production. In the Azores, eutrophication is a major concern, mainly in lakes where fertilizers and organic matter discharges have increased nutrient concentration. In this study, we [...] Read more.
Eutrophication and global climate change gather advantageous conditions for cyanobacteria proliferation leading to bloom formation and cyanotoxin production. In the Azores, eutrophication is a major concern, mainly in lakes where fertilizers and organic matter discharges have increased nutrient concentration. In this study, we focused on understanding the influence of environmental factors and lake characteristics on (i) cyanobacteria diversity and biomass and (ii) the presence of toxic strains and microcystin, saxitoxin, anatoxin-a, and cylindrospermopsin cyanotoxin-producing genes. Fifteen lakes from the Azores Archipelago were sampled seasonally, environmental variables were recorded in situ, cyanobacteria were analyzed with microscopic techniques, and cyanotoxin-producing genes were targeted through conventional PCR. Statistical analysis (DistLM) showed that lake typology-associated variables (lake’s depth, area, and altitude) were the most explanatory variables of cyanobacteria biomass and cyanotoxin-producing genes presence, although trophic variables (chlorophyll a and total phosphorus) influence species distribution in each lake type. Our main results revealed higher cyanobacteria biomass/diversity, and higher toxicity risk in lakes located at lower altitudes, associated with deep anthropogenic pressures and eutrophication scenarios. These results emphasize the need for cyanobacteria blooms control measures, mainly by decreasing anthropogenic pressures surrounding these lakes, thus decreasing eutrophication. We also highlight the potential for microcystin, saxitoxin, and anatoxin-a production in these lakes, hence the necessity to implement continuous mitigation protocols to avoid environmental and public health toxicity events. Full article
(This article belongs to the Section Water Quality and Contamination)
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19 pages, 3215 KiB  
Article
Diversity and Distribution Patterns of Hard Bottom Polychaete Assemblages in the North Adriatic Sea (Mediterranean)
by Barbara Mikac, Margherita Licciano, Andrej Jaklin, Ljiljana Iveša, Adriana Giangrande and Luigi Musco
Diversity 2020, 12(10), 408; https://doi.org/10.3390/d12100408 - 21 Oct 2020
Cited by 17 | Viewed by 3930
Abstract
The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of this paper was to update the information on polychaete diversity and depict their patterns of [...] Read more.
The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of this paper was to update the information on polychaete diversity and depict their patterns of natural spatial variation, in relation to changes in algal coverage at increasing depth. Hard bottom benthos was quantitatively sampled by scraping off the substrate from three stations at Sveti Ivan Island (North Adriatic) at three depths (1.5 m, 5 m and 25 m). Polychaete fauna comprised 107 taxa (the majority of them identified at species level) belonging to 22 families, with the family Syllidae ranking first in terms of number of species, followed by Sabellidae, Nereididae, Eunicidae and Serpulidae. Considering the number of polychaete species and their identity, the present data differed considerably from previous studies carried out in the area. Two alien species, Lepidonotus tenuisetosus, which represented a new record for the Adriatic Sea, and Nereis persica, were recorded. The highest mean abundance, species diversity and internal structural similarity of polychaete assemblages were found at 5 m depth, characterised by complex and heterogeneous algal habitat. The DISTLM forward analysis revealed that the distribution of several algal taxa as well as some algal functional-morphological groups significantly explained the observed distribution patterns of abundance and diversity of polychaete assemblages. The diversity of the North Adriatic hard bottom polychaete fauna is largely underestimated and needs regular updating in order to detect and monitor changes of benthic communities in the area. Full article
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18 pages, 1455 KiB  
Article
Analyzing the Performances of Water User Associations to Increase the Irrigation Sustainability: An Application of Multivariate Statistics to a Case Study in Italy
by Demetrio Antonio Zema, Pasquale Filianoti, Daniela D’Agostino, Antonino Labate, Manuel Esteban Lucas-Borja, Angelo Nicotra and Santo Marcello Zimbone
Sustainability 2020, 12(16), 6327; https://doi.org/10.3390/su12166327 - 6 Aug 2020
Cited by 14 | Viewed by 4197
Abstract
Benchmarking techniques are useful and simple tools to analyze the performance of the collective irrigation in the Water User Associations (WUAs) towards an increase in service sustainability. Several benchmarking techniques have been proposed to process and predict performance indicators. Instead, some meaningful statistical [...] Read more.
Benchmarking techniques are useful and simple tools to analyze the performance of the collective irrigation in the Water User Associations (WUAs) towards an increase in service sustainability. Several benchmarking techniques have been proposed to process and predict performance indicators. Instead, some meaningful statistical techniques based on the distance of data samples, which overcome the limitations of the traditional benchmarking techniques, have never been applied to the collective irrigation sector. This study applies Permutational Multivariate Analysis of Variance (PERMANOVA), Multidimensional Scale Models (MDS), and Distance-Based Linear Models (DISTLM) as benchmarking techniques to evaluate the technical and financial performances of 10 WUAs in Calabria (Southern Italy). These benchmarking techniques revealed that the significant differences in the irrigated areas and financial self-sufficiency of the WUAs, shown by PERMANOVA, depend on the large variability of the remaining performance indicators. Both the MDS and DISTLM demonstrated that a higher number of associated users and larger irrigation service coverage allows an increase in the irrigated areas; this enlargement is facilitated if the water price and the size of the personnel staff decrease. The WUAs’ self-sufficiency is mainly influenced by the number of workers and the maintenance, organization, and management costs, while the impacts of the due service fees and water price are more limited; it is also convenient to increase the number of the associated farmers since this increases the economy of scale and the gross revenues of the irrigation service. Overall, from the analysis carried out for the regional case study, these benchmarking techniques seem to be powerful and easy tools to identify the problems of the irrigation service and help in planning the most suitable policies to improve the sustainability of the collective irrigation at the regional scale. Full article
(This article belongs to the Special Issue Towards Sustainable Engineering: New Technologies and Methodologies)
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23 pages, 3099 KiB  
Article
Spatial and Temporal Variation in Deep-Sea Meiofauna at the LTER Observatory HAUSGARTEN in the Fram Strait (Arctic Ocean)
by Thomas Soltwedel, Katarzyna Grzelak and Christiane Hasemann
Diversity 2020, 12(7), 279; https://doi.org/10.3390/d12070279 - 13 Jul 2020
Cited by 12 | Viewed by 4138
Abstract
Time-series studies at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN have yielded the world’s longest time-series on deep-sea meiofauna and thus provide a decent basis to investigate the variability in deep-sea meiobenthic communities at different spatial and temporal scales. The main objective of [...] Read more.
Time-series studies at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN have yielded the world’s longest time-series on deep-sea meiofauna and thus provide a decent basis to investigate the variability in deep-sea meiobenthic communities at different spatial and temporal scales. The main objective of the present study was to investigate whether the sediment-dwelling meiofauna (size range: 32–1000 µm) is controlled by small-scale local environmental conditions, rather than large-scale differences between water depths. Univariate and multivariate statistical analyses, including distance-based linear models (DistLM) and redundancy analysis (dbRDA), revealed that due to their small size, meiofauna tend to mainly respond to micro-scale (centimeter) variations in environmental conditions in surface and subsurface sediment layers. Inter-annual temporal patterns among metazoan meiofauna at higher taxon levels revealed only a weak effect of time, and merely on the rare meiofauna taxa (<2% of the total meiofauna community) at HAUSGARTEN. Full article
(This article belongs to the Section Marine Diversity)
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