Ecology of Aquatic Animals in Freshwater

A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Ecology and Conservation".

Deadline for manuscript submissions: closed (30 November 2021) | Viewed by 17859

Special Issue Editor


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Guest Editor
Kongju National University, Gongju 32588, Korea
Interests: amphibian; animal ecology; conservation culturomics; indicator species; wetland

Special Issue Information

Dear Colleagues,

 Freshwater ecosystems account for less than 0.01% of the total surface area of the planet, but they support innumerable species. However, these ecosystems are experiencing a significant loss of biodiversity. Habitat alteration, erosion, deforestation in the catchment basin, invasive species, construction of dams and river channelization, pollution, disease, and climate change drive the loss of biodiversity in these ecosystems.

The aim of this Special Issue is to introduce reviews, notes, and original research that (not exhaustively) address the following topics: diversity of aquatic animals, food webs, genetic diversity of aquatic animals, enhanced monitoring methods for aquatic animals, and assessment of habitat quality using indicator aquatic animal species. Studies that improve our understanding of anthropogenic impacts and changes to aquatic animals in freshwater ecosystems are also appropriate.

Prof. Dr. Yuno Do
Guest Editor

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Keywords

  • Keywords: amphibian
  • aquatic animals
  • disturbance
  • fish
  • food webs
  • genetic diversity
  • mammal
  • zooplankton

Published Papers (7 papers)

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Research

15 pages, 2206 KiB  
Article
eDNA Metabarcoding Benchmarked towards Conventional Survey Methods in Amphibian Monitoring
by Anne Katrine Nørgaard Svenningsen, Cino Pertoldi and Dan Bruhn
Animals 2022, 12(6), 763; https://doi.org/10.3390/ani12060763 - 18 Mar 2022
Cited by 7 | Viewed by 2574
Abstract
A keystone in protection work is accurate and thorough the monitoring of amphibian species, and the currently applied conventional survey methods are invasive, time-consuming, and dependent on expert knowledge. Research suggests that eDNA metabarcoding is a precise and cost-efficient method that could supplement [...] Read more.
A keystone in protection work is accurate and thorough the monitoring of amphibian species, and the currently applied conventional survey methods are invasive, time-consuming, and dependent on expert knowledge. Research suggests that eDNA metabarcoding is a precise and cost-efficient method that could supplement the currently applied methods. The present study assessed the efficiency of conventional survey methods and eDNA metabarcoding in terms of species richness, the average number of detected species per site, the relative frequency of species occurrence, and the similarity of applied methods. The study found eDNA metabarcoding surveys to detect Lissotriton vulgaris (smooth newt), Triturus cristatus (great crested newt), Rana arvalis (moor frog), Rana temporaria (common frog), and Bufo bufo (common toad), as well as an average of 0.9 species per site, reflecting the species composition at the time of sampling in mid-July 2020. In addition to the species mentioned above, the conventional survey detected Epidalea calamita (natterjack toad) and an average of 1.7 species per site, reflecting the species composition at the time of sampling in early June 2020. The similarity between the methods applied in the present study was 27%, thus indicating a large number of unique observations of both eDNA metabarcoding and conventional surveys. The differences in detection can most likely be explained by the time of sampling, which was conducted a month apart. eDNA metabarcoding was efficient in detecting multiple amphibian species and produced unique observations that were not detected using conventional survey methods. Applying eDNA techniques as a supplement will most likely produce important knowledge on species distribution and presence, as well as enable more frequent monitoring due to cost efficiency and disturbance. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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18 pages, 2049 KiB  
Article
Response of Benthic Fauna to Habitat Heterogeneity in a Shallow Temperate Lake
by Krystian Obolewski, Katarzyna Glińska-Lewczuk, Marcin Sidoruk and Monika Magdalena Szymańska
Animals 2021, 11(9), 2488; https://doi.org/10.3390/ani11092488 - 25 Aug 2021
Cited by 4 | Viewed by 2376
Abstract
We investigated the response of benthic macroinvertebrates in the eulittoral, infralittoral, and sublittoral zones, in two segments of the freshwater Lake Wicko on the coast of the Baltic Sea. Our results showed that the morphometry of lakes plays a major role as a [...] Read more.
We investigated the response of benthic macroinvertebrates in the eulittoral, infralittoral, and sublittoral zones, in two segments of the freshwater Lake Wicko on the coast of the Baltic Sea. Our results showed that the morphometry of lakes plays a major role as a factor structuring the macroinvertebrates communities. Two parts of the lake, different in size and depth, show decreasing differences in the trophic state, abundance, diversity and number of indicator species of benthic fauna with the depth gradient. The most significant differences were observed between the littoral zones of both segments. Similar environmental conditions in the sublittoral zones corresponded to the simplified structure of the benthic macroinvertebrates communities. In the infralittoral zone, the most significant differences between the two segments, were recorded for mollusks and large crustaceans as well as the Oligochaeta/Chironomidae abundance ratio. In the sublittoral zone, the diversity of chironomids differed most strongly. Lower species diversity was found in the part of the lake with a slight depth decrease. Shredders reached significantly higher values in eulittoral and infralittoral of the deeper lake segment. Average Score Per Taxon increased with a depth gradient. We recommend testing benthic macroinvertebrates in lakes with different morphometrics individually for each depth zone. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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16 pages, 1479 KiB  
Article
The Invasive Round Goby Neogobius melanostomus as a Potential Threat to Native Crayfish Populations
by Pavel Franta, Radek Gebauer, Lukáš Veselý, Miloš Buřič, Natalia Z. Szydłowska and Bořek Drozd
Animals 2021, 11(8), 2377; https://doi.org/10.3390/ani11082377 - 12 Aug 2021
Cited by 3 | Viewed by 3077
Abstract
Despite the spread of round goby Neogobius melanostomus into freshwater streams, there is a lack of information with respect to its effect on macroinvertebrate communities, especially crustaceans. We studied foraging efficiency of N. melanostomus on Procambarus virginalis and Asellus aquaticus, using a [...] Read more.
Despite the spread of round goby Neogobius melanostomus into freshwater streams, there is a lack of information with respect to its effect on macroinvertebrate communities, especially crustaceans. We studied foraging efficiency of N. melanostomus on Procambarus virginalis and Asellus aquaticus, using a functional response (FR) approach. Stocking density of the prey species was manipulated to determine its effect on consumer utilization, with prey offered separately or combined at 1:1, 3:1, and 1:3 at each tested density. For both prey species, N. melanostomus exhibited type II FR, occasionally with a high proportion of non-consumptive mortality. Procambarus virginalis suffered a significantly higher attack rate compared to A. aquaticus. Neogobius melanostomus killed significantly more of the most prevalent prey, regardless of species. In trials with prey species of equal proportions, a difference in the number of each species killed was observed only at the highest density, at which P. virginalis was preferred. Neogobius melanostomus may be an important driver of population dynamics of prey species in the wild. The non-selective prey consumption makes N. melanostomus a potential threat to macrozoobenthic communities of river tributaries. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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15 pages, 1435 KiB  
Article
Morphological Variations of Wild Populations of Brycon dentex (Characidae, Teleostei) in the Guayas Hydrographic Basin (Ecuador). The Impact of Fishing Policies and Environmental Conditions
by Ana Gonzalez-Martinez, Carmen De-Pablos-Heredero, Martin González, Jorge Rodriguez, Cecilio Barba and Antón García
Animals 2021, 11(7), 1901; https://doi.org/10.3390/ani11071901 - 26 Jun 2021
Cited by 1 | Viewed by 2130
Abstract
The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction [...] Read more.
The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction of habitats. The aim of this study was to determine the morphometric variation in three wild populations of Brycon dentex in the Guayas basin rivers and their connections to fishing management and environmental conditions. A total of 200 mature fish were captured, and 26 morphometric parameters were measured. The fishing policies (Hypothesis 1) and environmental conditions (Hypothesis 2) were considered fixed factors and were validated by t-tests. The morphological variation among the three populations (Hypothesis 3) was validated through a discriminant analysis. Fishing policies and resource management were found to generate morphological differences associated with body development. In addition, the environmental conditions were found to influence the size and structure of Brycon dentex populations. The analyzed populations were discriminated by the generated morphometric models, which differentiated Cluster 1 (Quevedo and Mocache rivers) with high fishing pressure from Cluster 2 (Pintado river) with medium–low fishing pressure. Morphometric differentiation by discriminant analysis is a direct and economic methodology that can be applied as an indicator of diversity maintenance. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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11 pages, 1079 KiB  
Article
Reference Intervals in Combined Veterinary Clinical Examinations of Male Black-Spotted Pond Frogs (Pelophylax nigromaculatus)
by Jun-Kyu Park, Jeong-Bae Kim and Yuno Do
Animals 2021, 11(5), 1407; https://doi.org/10.3390/ani11051407 - 14 May 2021
Cited by 8 | Viewed by 2232
Abstract
In conservation physiology, analyzing the physiological response of an organism to understand its ability to adapt to environmental changes is a key technique in establishing a successful conservation strategy. Veterinary clinical examinations determine the physiological condition of animals accurately and safely, and this [...] Read more.
In conservation physiology, analyzing the physiological response of an organism to understand its ability to adapt to environmental changes is a key technique in establishing a successful conservation strategy. Veterinary clinical examinations determine the physiological condition of animals accurately and safely, and this examination is synergistic when combined. The accuracy and safety of a clinical examination makes it advantageous for use in amphibians with high species diversity and numerous endangered species. However, it is necessary to establish a reference interval (RI) for precise interpretations and identification of animals with abnormalities through individual unit testing. We have established RIs for the immunity, serum components, bone mineral density (BMD), and body composition of black-spotted pond frogs (Pelophylax nigromaculatus). Black-spotted pond frogs are a common species and are widely distributed in East Asia, with suitable characteristics for environmental monitoring. Serum was extracted from 151 male frogs to establish the RI for bacterial killing ability in order to represent immunity. We also used the serum to establish an RI of ten additional serum components to determine the nutritional status, organ function status, body osmotic pressure, and homeostasis conditions. The BMD and three body composition measures for diagnosing food intake status and nutritional condition were measured using dual energy X-ray absorptiometry. The RI was recorded as the mean ± standard deviation, median, first (25%) to third (75%) quantile range, 95% confidence interval of the mean and median, and the 95% percentile (2.5%–97.5% range) of all components. The use of combined clinical veterinary examinations aids our understanding of the physiological conditions of an individual according to biotic and abiotic factors on a complex spatiotemporal scale in an ecosystem. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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14 pages, 3048 KiB  
Article
Application of Next-Generation Sequencing for the Determination of the Bacterial Community in the Gut Contents of Brackish Copepod Species (Acartia hudsonica, Sinocalanus tenellus, and Pseudodiaptomus inopinus)
by Yeon-Ji Chae, Hye-Ji Oh, Kwang-Hyeon Chang, Ihn-Sil Kwak and Hyunbin Jo
Animals 2021, 11(2), 542; https://doi.org/10.3390/ani11020542 - 19 Feb 2021
Cited by 4 | Viewed by 2177
Abstract
The gut bacterial communities of copepods can affect metabolic processes, and consequently, their activity can be related to the release of organic substances to the environment. Hence, they are important for organic matter cycling in marine coast food webs. However, information regarding the [...] Read more.
The gut bacterial communities of copepods can affect metabolic processes, and consequently, their activity can be related to the release of organic substances to the environment. Hence, they are important for organic matter cycling in marine coast food webs. However, information regarding the variation in gut bacterial communities based on copepod species and environmental variations is limited. We analysed the differences in gut bacterial communities from dominant copepod species, i.e., Acartia hudsonica, Sinocalanus tenellus, and Pseudodiaptomus inopinus, in a brackish reservoir. The core bacteria among the copepod species and locations consisted of the following main operational taxonomic units (OTUs): Novosphingobium capsulatum and the family Rhodobacteraceae belonging to Alphaproteobacteria, which is abundant in seawater and freshwater aquatic ecosystems as a zooplankton-associated bacterial community. The bacterial community composition of each copepod (except the core species) showed high variability. The bacterial community diversity differed depending on the copepod species and the sites’ environmental conditions, especially salinity, e.g., compositional variations in the bacterial community of P. inopinus were high at sites with low salinity. Therefore, the gut bacterial community of each copepod species responds differently to the environment. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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14 pages, 8426 KiB  
Article
Movement Patterns and Diel Activity of Anguilla japonica in the Middle Part of a Large River in South Korea
by Jeong-Hui Kim, Sang-Hyeon Park, Seung-Ho Baek, Min-Ho Jang and Ju-Duk Yoon
Animals 2020, 10(12), 2424; https://doi.org/10.3390/ani10122424 - 17 Dec 2020
Cited by 1 | Viewed by 1852
Abstract
To investigate movement patterns and diel activities of Anguilla japonica in the freshwater ecosystem, we applied acoustic telemetry on A. japonica in the Geum River, a large river in South Korea. The acoustic tags were attached on 19 individuals of A. japonica (12 [...] Read more.
To investigate movement patterns and diel activities of Anguilla japonica in the freshwater ecosystem, we applied acoustic telemetry on A. japonica in the Geum River, a large river in South Korea. The acoustic tags were attached on 19 individuals of A. japonica (12 with a depth sensor) in May and October 2015 and tracked at approximately 100-km sections from an estuary barrage by 20 automatic listening stations. Only four individuals showed longitudinal movement (mean, 5.2 km), and others were detected by the receivers at release sites; therefore, A. japonica showed high site fidelity. We did not identify seaward migration during the study period (May to November). Conversely, A. japonica showed active diel movement. The number of detections (p = 0.002) and movement distance (p = 0.004) were higher at night-time (18:00–06:00). As most individuals were actively moving at nighttime, we confirmed that A. japonica is nocturnal, although few individuals also showed daytime movement. Although the population and habitats of A. japonica have been decreasing simultaneously, the East-Asian countries are still severely exploiting rivers and streams to use water resources, and result in habitat simplification generated. Therefore, these results contribute to effective A. japonica management regarding habitat and population conservation and restoration. Full article
(This article belongs to the Special Issue Ecology of Aquatic Animals in Freshwater)
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