Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (126)

Search Parameters:
Keywords = benthic reflectance

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
17 pages, 15945 KiB  
Article
Mapping Subtidal Marine Forests in the Mediterranean Sea Using Copernicus Contributing Mission
by Dimitris Poursanidis and Stelios Katsanevakis
Remote Sens. 2025, 17(14), 2398; https://doi.org/10.3390/rs17142398 - 11 Jul 2025
Viewed by 393
Abstract
Mediterranean subtidal reefs host ecologically significant habitats, including forests of Cystoseira spp., which form complex benthic communities within the photic zone. These habitats are increasingly degraded due to climate change, invasive species, and anthropogenic pressures, particularly in the eastern Mediterranean. In support of [...] Read more.
Mediterranean subtidal reefs host ecologically significant habitats, including forests of Cystoseira spp., which form complex benthic communities within the photic zone. These habitats are increasingly degraded due to climate change, invasive species, and anthropogenic pressures, particularly in the eastern Mediterranean. In support of habitat monitoring under the EU Natura 2000 directive and the Nature Restoration Regulation, this study investigates the utility of high-resolution satellite remote sensing for mapping subtidal brown algae and associated benthic classes. Using imagery from the SuperDove sensor (Planet Labs, San Francisco, CA, USA), we developed an integrated mapping workflow at the Natura 2000 site GR2420009. Aquatic reflectance was derived using ACOLITE v.20250114.0, and both supervised classification and spectral unmixing were implemented in the EnMAP Toolbox v.3.16.3 within QGIS. A Random Forest classifier (100 fully grown trees) achieved high thematic accuracy across all habitat types (F1 scores: 0.87–1.00), with perfect classification of shallow soft bottoms and strong performance for Cystoseira s.l. (F1 = 0.94) and Seagrass (F1 = 0.93). Spectral unmixing further enabled quantitative estimation of fractional cover, with high predictive accuracy for deep soft bottoms (R2 = 0.99; RPD = 18.66), shallow soft bottoms (R2 = 0.98; RPD = 8.72), Seagrass (R2 = 0.88; RPD = 3.01) and Cystoseira s.l. (R2 = 0.82; RPD = 2.37). The lower performance for rocky reefs with other cover (R2 = 0.71) reflects spectral heterogeneity and shadowing effects. The results highlight the effectiveness of combining classification and unmixing approaches for benthic habitat mapping using CubeSat constellations, offering scalable tools for large-area monitoring and ecosystem assessment. Despite challenges in field data acquisition, the presented framework provides a robust foundation for remote sensing-based conservation planning in optically shallow marine environments. Full article
(This article belongs to the Special Issue Marine Ecology and Biodiversity by Remote Sensing Technology)
Show Figures

Graphical abstract

14 pages, 1211 KiB  
Article
Fish Fauna, Ecological Quality and Conservation Challenges in the Balkan Transboundary Lake Dojran
by Spase Shumka, Olga Petriki, Laura Shumka and Enkeleda Berberi
Fishes 2025, 10(6), 272; https://doi.org/10.3390/fishes10060272 - 4 Jun 2025
Viewed by 515
Abstract
The European Water Framework Directive (WFD) 2000/60/EC emphasizes the use of fish communities as key indicators for assessing the ecological quality of freshwater ecosystems. Despite over two decades of WFD implementation, many Balkan countries lack standardized ecological assessment indices, particularly for fish fauna. [...] Read more.
The European Water Framework Directive (WFD) 2000/60/EC emphasizes the use of fish communities as key indicators for assessing the ecological quality of freshwater ecosystems. Despite over two decades of WFD implementation, many Balkan countries lack standardized ecological assessment indices, particularly for fish fauna. This situation complicates efforts to monitor and manage aquatic ecosystems, especially transboundary waters facing significant environmental pressures. In this context, our study assesses fish communities and ecological quality in Lake Dojran, a transboundary lake shared by Greece and North Macedonia. Fish sampling was independently conducted by each country (North Macedonia in 2021 and Greece in 2023), using benthic multi-mesh gillnets following standardized European methodologies (CEN 2005). A total of 12 out of 16 historically recorded fish species were confirmed. Higher catch per unit effort (CPUE) values were observed in 2021 (282.50 specimens/gillnet, biomass 6321.81 g/gillnet) compared to 2023 (207.83 specimens/gillnet, 2378.67 g/gillnet). Dominant species included Alburnus macedonicus and Perca fluviatilis. No significant differences were found in CPUE values based on either number of specimens (NPUE) or biomass (BPUE) across the different depth zones. Using the Greek Lake Fish Index (GLFI), ecological quality based on fish fauna was classified as “good” in 2021 and “high” in 2023, reflecting the low relative contribution of both introduced numerical abundance and omnivorous species biomass in total catches. This study contributes valuable baseline data for transboundary ecological management and conservation strategies, supporting efforts aligned with WFD objectives. Full article
(This article belongs to the Section Biology and Ecology)
Show Figures

Graphical abstract

13 pages, 2879 KiB  
Article
Biodiversity Conservation and Survival Factors of Charophyte Algal Communities in Protected High-Mountain Lakes of Kaçkar Mountains National Park (Rize, Turkey)
by Bülent Şahin and Sophia Barinova
Conservation 2025, 5(1), 14; https://doi.org/10.3390/conservation5010014 - 6 Mar 2025
Viewed by 3247
Abstract
The composition and diversity of the sensitive benthic Charophyta were examined in 13 lakes and 1 pond located in the Kaçkar Mountains National Park during the summer and autumn months of 2020. While a total of 78 taxa were identified, Cosmarium became the [...] Read more.
The composition and diversity of the sensitive benthic Charophyta were examined in 13 lakes and 1 pond located in the Kaçkar Mountains National Park during the summer and autumn months of 2020. While a total of 78 taxa were identified, Cosmarium became the main genus of the flora with 33 species. In the flora, the filamentous members of the Charophyta (12 species) were also noteworthy. Intraspecies variability is very high, with a Subspecies/Species index of 1.11, which reflects the sensitivity of the identified charophyte flora as an indicator of conservation efficiency. The physico-chemical analysis results and bioindicator species indicate that the investigated waters are fresh, with low salinity and a circumneutral or slightly alkaline pH, and are not organically polluted. Comparative statistics and RDA divide the studied lakes into two clusters (northern and southern in the park territory) and reveal the complex factors related to salinity and oxygen saturation as regulators of species abundance in communities. Full article
Show Figures

Figure 1

16 pages, 5688 KiB  
Article
Composition and Spatial Distribution of Benthic Foraminifera from Two Tropical Estuaries (7° S, Brazil)
by Bruna Marinho Alves, Patricia Beck Eichler-Barker and Miodeli Nogueira Júnior
Diversity 2025, 17(3), 142; https://doi.org/10.3390/d17030142 - 20 Feb 2025
Viewed by 609
Abstract
This study investigates the composition and spatial distribution of benthic foraminiferal assemblages in the estuaries of the Mamanguape and Paraíba rivers in Northeast Brazil. Samples were collected from different sectors along both estuaries and analyzed for foraminiferal density, diversity, and species composition in [...] Read more.
This study investigates the composition and spatial distribution of benthic foraminiferal assemblages in the estuaries of the Mamanguape and Paraíba rivers in Northeast Brazil. Samples were collected from different sectors along both estuaries and analyzed for foraminiferal density, diversity, and species composition in relation to abiotic factors like salinity, temperature, pH, and sediment grain size. Results show that calcareous foraminifera dominate both estuaries, likely influenced by stable pH and salinity gradients. Additionally, the sediment composition of both estuaries varies from typical tropical estuarine patterns, with the presence of coarse and medium sands suggesting significant environmental dynamics. Statistical analyses confirm that foraminiferal assemblages reflect spatial environmental variations within and between the estuaries, underscoring the potential of foraminifera as bioindicators in coastal ecosystem assessments. Full article
(This article belongs to the Special Issue Foraminiferal Research: Modern Approaches and Emerging Trends)
Show Figures

Figure 1

16 pages, 17053 KiB  
Article
Adding to Our Knowledge on the Diatom and Green Algae Biodiversity of Egypt: Some New-to-Science, Poorly Known, and Newly Recorded Species
by Abdullah A. Saber, Mostafa M. El-Sheekh, Olfat M. A. Salem, Zlatko Levkov, Marco Cantonati, Modhi O. Alotaibi and Hani Saber
Water 2025, 17(3), 446; https://doi.org/10.3390/w17030446 - 5 Feb 2025
Viewed by 997
Abstract
During our research on the diversity of diatoms and green microalgae from Egypt, four new-to-science, newly recorded, and poorly known species were retrieved from different Egyptian habitats. The new benthic diatom species Halamphora shaabanii A.A. Saber, El-Sheekh, Levkov, H. Saber et Cantonati sp. [...] Read more.
During our research on the diversity of diatoms and green microalgae from Egypt, four new-to-science, newly recorded, and poorly known species were retrieved from different Egyptian habitats. The new benthic diatom species Halamphora shaabanii A.A. Saber, El-Sheekh, Levkov, H. Saber et Cantonati sp. nov., which could not be identified using the currently available literature, was described from the high-conductivity, oasis lake Abu Nuss in the El-Farafra Oasis, located in the Western Desert of Egypt, employing both light (LM) and scanning electron (SEM) microscopy observations. A detailed comparison of the biometrically distinctive traits, and ecological preferences, of this new diatom species revealed sufficient differentiations from its morphologically most closely related species: H. atacamana, H. caribaea, H. ectorii, H. gasseae, H. halophila, H. mosensis, H. poianensis, and H. vantushpaensis. Ecologically, Halamphora shaabanii can tolerate relatively high nutrients (N and P) and prefers saline inland environments with NaCl water types. The araphid diatom Pseudostaurosiropsis geocollegarum was observed in the epilithic diatom assemblages of the River Nile Damietta Branch and identified on the basis of LM and SEM. From an ecological standpoint, P. geocollegarum seems to prefer elevated nutrient concentrations (meso-eutraphentic species), reflecting different human influences on the freshwater River Nile Damietta Branch. Based on the available literature, this is the first documentation of this freshwater diatom species for Egypt, and the second record for the African continent. Two green motile microalgae, Chlamydomonas proboscigera and Gonium pectorale, were isolated and identified from the terrestrial biomes of the arid habitat “Wadi El-Atshan” in the Eastern Desert of Egypt. C. proboscigera is reported herein for the first time in the Egyptian algal flora, while G. pectorale is poorly documented in the available literature. In light of our findings, the Egyptian habitats, particularly the isolated desert ecosystems, are interesting biodiversity hotspots and have a richer algal microflora than earlier anticipated. Furthermore, more in-depth taxonomic studies, using a combined polyphasic approach, are needed not only to foster our knowledge of the Egyptian and African algal and cyanobacterial diversity and biogeography, but also to be further used in applied environmental sciences. Full article
(This article belongs to the Special Issue Biodiversity of Freshwater Ecosystems: Monitoring and Conservation)
Show Figures

Graphical abstract

17 pages, 4713 KiB  
Article
Rapoport’s Rule, the Ecotone Concept, and Salinity Gradient Predict the Distribution of Benthic Foraminifera in a Southeastern Pacific Estuary
by Leonardo D. Fernández and Margarita Marchant
Ecologies 2025, 6(1), 11; https://doi.org/10.3390/ecologies6010011 - 2 Feb 2025
Cited by 1 | Viewed by 826
Abstract
This study explores the biogeographic processes shaping the distribution of benthic foraminifera along a salinity gradient in the Contaco Estuary, southeastern Pacific, Chile. The primary aim was to evaluate the applicability of key ecological paradigms—Rapoport’s rule, the mid-domain effect, ecotones, and source–sink dynamics—to [...] Read more.
This study explores the biogeographic processes shaping the distribution of benthic foraminifera along a salinity gradient in the Contaco Estuary, southeastern Pacific, Chile. The primary aim was to evaluate the applicability of key ecological paradigms—Rapoport’s rule, the mid-domain effect, ecotones, and source–sink dynamics—to unicellular eukaryotes in estuarine environments. A 1550 m longitudinal transect, sampled at 50 m intervals, revealed a pronounced salinity-driven pattern in species richness and diversity, with calcareous taxa dominating euhaline zones and agglutinated taxa thriving in brackish and freshwater areas. Source–sink dynamics were not supported, as beta diversity analyses identified turnover as the dominant driver, highlighting species replacement along the salinity gradient. Evidence of a longitudinal Rapoport effect was observed, with broader distribution ranges in low-salinity environments, reflecting adaptations to suboptimal conditions. Contrary to predictions, the mid-domain effect was not supported, as foraminiferal richness showed a monotonic decline. These findings extend macroecological principles to microbial communities, emphasizing deterministic processes in shaping estuarine diversity. This research provides a robust framework for understanding biodiversity patterns in dynamic ecosystems, offering valuable insights for conservation and ecological monitoring. Full article
Show Figures

Figure 1

27 pages, 7608 KiB  
Article
Occurrence of Microplastics in the Sediments of an Irish River and Their Effects on Nematode Survival and Biodiversity
by Loriane Murphy, Kieran Germaine, John Cleary and Thomais Kakouli-Duarte
Appl. Biosci. 2024, 3(4), 532-558; https://doi.org/10.3390/applbiosci3040034 - 13 Dec 2024
Cited by 1 | Viewed by 1432
Abstract
Microplastics (MPs), defined as plastic particles of less than 5 mm, pose a significant global environmental threat, particularly in aquatic ecosystems, due to their persistence and potential harmful effects on wildlife and human health. They can absorb persistent organic pollutants (POPs), like polycyclic [...] Read more.
Microplastics (MPs), defined as plastic particles of less than 5 mm, pose a significant global environmental threat, particularly in aquatic ecosystems, due to their persistence and potential harmful effects on wildlife and human health. They can absorb persistent organic pollutants (POPs), like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), raising concerns about their impact on biota. To elucidate this impact, the present study employed attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to analyse the characteristics of MPs sourced from commercial cosmetics. We investigated the toxicity of MPs on Caenorhabditis elegans and two entomopathogenic nematode species, Steinernema feltiae (the enviroCORE strain SB12(1)) and Steinernema carpocapsae (a commercial strain from e-NEMA) in laboratory bioassays. Nematodes were exposed to various concentrations of MPs and other pollutants, including atrazine, 1,3-dichloropropene, naphthalene, and fluorene, in controlled settings over 72 to 96 h. Additionally, high-throughput 18S rDNA sequencing was used to analyse nematode biodiversity in sediments from the River Barrow (RB) in SE Ireland. Our findings revealed that MPs increased nematode mortality and adversely affected community structure, as indicated by nematode maturity and sigma maturity indices, suggesting a potential disruption of the ecological balance in river sediments. This highlighted the ecological risks posed by MP pollution and emphasised the urgent need for further research into the health of benthic ecosystems in Ireland, particularly in relation to how MPs may influence nematode community dynamics and biodiversity. Full article
Show Figures

Figure 1

24 pages, 6941 KiB  
Article
Discriminating Seagrasses from Green Macroalgae in European Intertidal Areas Using High-Resolution Multispectral Drone Imagery
by Simon Oiry, Bede Ffinian Rowe Davies, Ana I. Sousa, Philippe Rosa, Maria Laura Zoffoli, Guillaume Brunier, Pierre Gernez and Laurent Barillé
Remote Sens. 2024, 16(23), 4383; https://doi.org/10.3390/rs16234383 - 23 Nov 2024
Viewed by 1780
Abstract
Coastal areas support seagrass meadows, which offer crucial ecosystem services, including erosion control and carbon sequestration. However, these areas are increasingly impacted by human activities, leading to habitat fragmentation and seagrass decline. In situ surveys, traditionally performed to monitor these ecosystems, face limitations [...] Read more.
Coastal areas support seagrass meadows, which offer crucial ecosystem services, including erosion control and carbon sequestration. However, these areas are increasingly impacted by human activities, leading to habitat fragmentation and seagrass decline. In situ surveys, traditionally performed to monitor these ecosystems, face limitations on temporal and spatial coverage, particularly in intertidal zones, prompting the addition of satellite data within monitoring programs. Yet, satellite remote sensing can be limited by too coarse spatial and/or spectral resolutions, making it difficult to discriminate seagrass from other macrophytes in highly heterogeneous meadows. Drone (unmanned aerial vehicle—UAV) images at a very high spatial resolution offer a promising solution to address challenges related to spatial heterogeneity and the intrapixel mixture. This study focuses on using drone acquisitions with a ten spectral band sensor similar to that onboard Sentinel-2 for mapping intertidal macrophytes at low tide (i.e., during a period of emersion) and effectively discriminating between seagrass and green macroalgae. Nine drone flights were conducted at two different altitudes (12 m and 120 m) across heterogeneous intertidal European habitats in France and Portugal, providing multispectral reflectance observation at very high spatial resolution (8 mm and 80 mm, respectively). Taking advantage of their extremely high spatial resolution, the low altitude flights were used to train a Neural Network classifier to discriminate five taxonomic classes of intertidal vegetation: Magnoliopsida (Seagrass), Chlorophyceae (Green macroalgae), Phaeophyceae (Brown algae), Rhodophyceae (Red macroalgae), and benthic Bacillariophyceae (Benthic diatoms), and validated using concomitant field measurements. Classification of drone imagery resulted in an overall accuracy of 94% across all sites and images, covering a total area of 467,000 m2. The model exhibited an accuracy of 96.4% in identifying seagrass. In particular, seagrass and green algae can be discriminated. The very high spatial resolution of the drone data made it possible to assess the influence of spatial resolution on the classification outputs, showing a limited loss in seagrass detection up to about 10 m. Altogether, our findings suggest that the MultiSpectral Instrument (MSI) onboard Sentinel-2 offers a relevant trade-off between its spatial and spectral resolution, thus offering promising perspectives for satellite remote sensing of intertidal biodiversity over larger scales. Full article
(This article belongs to the Section Ecological Remote Sensing)
Show Figures

Figure 1

18 pages, 1927 KiB  
Article
Spatial Patterns and Environmental Control of Polychaete Communities in the Southwestern Barents Sea
by Dinara R. Dikaeva and Alexander G. Dvoretsky
Biology 2024, 13(11), 924; https://doi.org/10.3390/biology13110924 - 13 Nov 2024
Cited by 4 | Viewed by 1015
Abstract
The Barents Sea region is influenced by an increased inflow of warm Atlantic water, which impacts all components of the local ecosystem. Information on the state of benthic communities is required to predict alterations in the food web’s structure and functioning. The spatial [...] Read more.
The Barents Sea region is influenced by an increased inflow of warm Atlantic water, which impacts all components of the local ecosystem. Information on the state of benthic communities is required to predict alterations in the food web’s structure and functioning. The spatial distribution of polychaete communities was investigated in relation to environmental conditions at nine stations along the Kola Transect (70°00′–74°00′ N, 33°30′ E) in April 2019. A taxonomically diverse fauna containing 114 taxa was found, with 95 identified at the species level. The fauna was composed predominantly of boreo-Arctic species (63%), followed by boreal (22%) and Arctic species (13%). The polychaete abundance and biomass exhibited considerable variability, ranging from 910 to 3546 ind. m−2 and from 3.4 to 72.7 g m−2, with average values of 1900 ind. m−2 and 18.7 g m−2, respectively. Cluster analysis revealed three distinct polychaete communities differing in dominant species composition, abundance, and biomass. The southern region featured the most abundant community, the middle part exhibited the highest diversity, and the northern area presented the community with the highest biomass. These spatial variations in community structure corresponded closely to the distribution and properties of water masses within the study area. Multivariate analysis identified depth as the primary driver of diversity indices, with higher values observed at shallow water sites. Salinity and water temperature together explained 46% of the variation in abundance, reflecting warming effects and showing positive or negative effects, depending on the taxa. Furthermore, an increase in water temperature had a positive impact on the contribution of boreal species to the total material, while exerting a strong negative effect on the overall community biomass, underscoring the potential of polychaetes in biological indication. Full article
(This article belongs to the Special Issue Feature Papers in 'Conservation Biology and Biodiversity')
Show Figures

Figure 1

22 pages, 14858 KiB  
Article
Clam Genome and Transcriptomes Provide Insights into Molecular Basis of Morphological Novelties and Adaptations in Mollusks
by Xiujun Sun, Xi Chen, Biao Wu, Liqing Zhou, Yancui Chen, Sichen Zheng, Songlin Wang and Zhihong Liu
Biology 2024, 13(11), 870; https://doi.org/10.3390/biology13110870 - 25 Oct 2024
Viewed by 2247
Abstract
Bivalve mollusks, comprising animals enclosed in two shell valves, are well-adapted to benthic life in many intertidal zones. Clams have evolved the buried lifestyle, which depends on their unique soft tissue structure and their wedge-shaped muscular foot and long extendible siphons. However, molecular [...] Read more.
Bivalve mollusks, comprising animals enclosed in two shell valves, are well-adapted to benthic life in many intertidal zones. Clams have evolved the buried lifestyle, which depends on their unique soft tissue structure and their wedge-shaped muscular foot and long extendible siphons. However, molecular mechanisms of adaptative phenotype evolution remain largely unknown. In the present study, we obtain the high-quality chromosome-level genome of Manila clam R. philippinarum, an economically important marine bivalve in many coastal areas. The genome is constructed by the Hi-C assisted assembly, which yields 19 chromosomes with a total of 1.17 Gb and BUSCO integrity of 92.23%. The de novo assembled genome has a contig N50 length of 307.7 kb and scaffold N50 of 59.5 Mb. Gene family expansion analysis reveals that a total of 24 single-copy gene families have undergone the significant expansion or contraction, including E3 ubiquitin ligase and dynein heavy chain. The significant expansion of transposable elements has been also identified, including long terminal repeats (LTR) and non-LTR retrotransposons. The comparative transcriptomics among different clam tissues reveals that extracellular matrix (ECM) receptors and neuroactive ligand receptors may play the important roles in tissue structural support and neurotransmission during their infaunal life. These findings of gene family expansion and tissue-specific expression may reflect the unique soft tissue structure of clams, suggesting the evolution of lineage-specific morphological novelties. The high-quality genome and transcriptome data of R. philippinarum will not only facilitate the genetic studies on clams but will also provide valuable information on morphological novelties in mollusks. Full article
(This article belongs to the Section Marine Biology)
Show Figures

Figure 1

15 pages, 2936 KiB  
Article
Rapid Monitoring of Aquatic Organism Biodiversity Based on Environmental DNA in a Medium-Sized Reservoir
by Hui Jia, Mingxia Xia, Tao Zhang and Hui Zhang
Fishes 2024, 9(10), 396; https://doi.org/10.3390/fishes9100396 - 30 Sep 2024
Viewed by 1176
Abstract
Environmental DNA (eDNA) has emerged as a highly sensitive and efficient tool for the biomonitoring of aquatic ecosystems. In this study, we investigated fish and benthic species communities using eDNA techniques in a medium-sized reservoir (about 3 square kilometers) in Anhui, China. A [...] Read more.
Environmental DNA (eDNA) has emerged as a highly sensitive and efficient tool for the biomonitoring of aquatic ecosystems. In this study, we investigated fish and benthic species communities using eDNA techniques in a medium-sized reservoir (about 3 square kilometers) in Anhui, China. A total of 12 water samples and 11 sediment samples were analyzed by 12S and 18S primers, respectively. We analyzed the composition of species diversity and the effect of seven environmental factors using the Mantel test. A total of 42 fish taxa were present in the water samples, and 188 benthic taxa in the sediment samples. Species composition was different in disparate stations. We found that water temperature and salinity are pivotal factors influencing the composition of fish communities, while chlorophyll-a is a primary environmental determinant for benthic species assembly structures across different zones. Biodiversity information generated by eDNA techniques can be used to reflect the resource status of this reservoir. The relevant results will provide important scientific reference information for the development and exploitation of medium-sized reservoirs. Full article
(This article belongs to the Special Issue Assessment and Management of Fishery Resources)
Show Figures

Figure 1

16 pages, 1616 KiB  
Article
Species Richness and Similarity of New Zealand Mayfly Communities (Ephemeroptera) Decline with Increasing Latitude and Altitude
by Stephen R. Pohe, Michael J. Winterbourn and Jon S. Harding
Insects 2024, 15(10), 757; https://doi.org/10.3390/insects15100757 - 29 Sep 2024
Viewed by 1459
Abstract
The distribution of species in relation to latitude and altitude is of fundamental interest to ecologists and is expected to attain increasing importance as the Earth’s climate continues to change. Species diversity is commonly greater at lower than higher latitudes on a global [...] Read more.
The distribution of species in relation to latitude and altitude is of fundamental interest to ecologists and is expected to attain increasing importance as the Earth’s climate continues to change. Species diversity is commonly greater at lower than higher latitudes on a global scale, and the similarity of communities frequently decreases with distance. Nevertheless, reasons for such patterns are not well understood. We investigated species richness and changes in community composition of mayflies (Ephemeroptera) over 13 degrees of latitude at 81 locations throughout New Zealand by light-trapping and the benthic sampling of streams. Mayflies were also sampled along an altitudinal gradient on a prominent inactive volcano in the east of North Island. Sampled streams were predominantly in the native forest, at a wide range of altitudes from sea level to c. 1000 m a. s. l. A total of 47 of the 59 described New Zealand mayflies were recorded during the study, along with five undescribed morphospecies. Species richness declined and the degree of dissimilarity (beta diversity) of mayfly communities increased significantly from north to south but less strongly with increasing altitude. Our results suggest that the southward decline in species richness has historical origins with the north of the country having acted as a major refuge and region of speciation during the Pleistocene. The increasing dissimilarity of the northern and southern communities may reflect an increasingly harsh climate, variable amounts of subsequent southward dispersal of northern species and, in the South Island, the presence of species which may have evolved in the newly uplifted mountains during the Miocene–Pliocene. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
Show Figures

Figure 1

13 pages, 1815 KiB  
Article
Detailed Insight into Gillnet Catches: Fish Directivity and Micro Distribution
by Karlos Moraes, Allan T. Souza, Mojmír Vašek, Milan Říha and Jan Kubečka
Water 2024, 16(18), 2683; https://doi.org/10.3390/w16182683 - 20 Sep 2024
Cited by 1 | Viewed by 1091
Abstract
Gillnets are widely used in research and commercial fishery activities. As passive gear, gillnets can be selective and dependent on the diel migration of fish. In areas with limited littoral extent, inshore–offshore migration may cause bias in the gillnet catch. Our hypothesis was [...] Read more.
Gillnets are widely used in research and commercial fishery activities. As passive gear, gillnets can be selective and dependent on the diel migration of fish. In areas with limited littoral extent, inshore–offshore migration may cause bias in the gillnet catch. Our hypothesis was that some factors, such as gillnet saturation, fish depletion, or chemical cues, could be the cause of the bias. We used a total of 66 CEN gillnets deployed at Římov Reservoir parallel to the shore at different positions of littoral-pelagic gradient. Individual fish direction was recorded from inshore, offshore, or unknown direction (i.e., entangled fish). A total of 5791 fishes from nine different species were caught. For most fish, it was possible to determine their directivity, and most fish were captured in littoral or first pelagic gillnets. Shallower and deeper benthic gillnets differed in their bleak (Alburnus alburnus) catch. No significant differences were found between fish directions. At the species level, only asp (Leuciscus aspius) and ruffe (Gymnocephalus cernua) showed differences between the captured directions in one case. The results support the assumption that gillnet capture is a random process that to a great extent is connected to random local movements. This is good news for fish monitoring projects. Sampling catch is likely to reflect true changes in the fish community, and not the effects of the deployment of the sampling gear. The experiment also showed that fish directivity statistics can be used for investigation of fish behavior and gear performance. Full article
(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)
Show Figures

Figure 1

17 pages, 4786 KiB  
Article
Distribution Profile of Benthic Macroinvertebrates in Some Rivers of Yaoundé City and Its Surroundings Using Self Organizing Map and Indicator value methods
by Marie Anita Temgoua Zemo, Samuel Foto Menbohan, Bernard Tossou Atchrimi, Delagnon Assou, Belmond Eric Biram à Ngon, Noel Christiane Wilfreid Betsi, Serge Gwos Nhiomock, Harissou, Nathaniel Larry Lactio, Bolivar Far Ndourwe, Mathias Nwaha, Donald l’or Nyame Mbia, Laure Yvonne Tchouapi, Ghislain Ulric Tchouta, Blaise Rollinat Mboye and Jean Dzavi
Diversity 2024, 16(7), 385; https://doi.org/10.3390/d16070385 - 2 Jul 2024
Viewed by 2092
Abstract
Urban sprawl leads to the degradation of aquatic environments and, consequently, to the destruction of biodiversity. With the aim of highlighting the distribution profile of benthic macroinvertebrates in the city of Yaoundé and its surroundings according to the level of degradation, this study [...] Read more.
Urban sprawl leads to the degradation of aquatic environments and, consequently, to the destruction of biodiversity. With the aim of highlighting the distribution profile of benthic macroinvertebrates in the city of Yaoundé and its surroundings according to the level of degradation, this study was carried out in seven rivers. A total of 144 taxa of benthic macroinvertebrates, belonging to 74 families, 15 orders, five classes, and three phyla, were collected from seven rivers in urban, peri-urban, and forest environments on Yaoundé and its surroundings. The self-organizing map (SOM) analysis tool was used to group the collected taxa from all stations into three clusters or affinity cores. The indicator value analysis (IndVal) method was employed to determine, based on their ecological preferences, which organisms were most likely to belong to each group. Out of the 144 collected taxa, only 44 were indicated to represent the three different groups. Thus, three communities were defined: the Hydropsyche community, with Hydropsyche sp. as the predominant taxon in Group III, characterizing well-oxygenated and low-mineralized stations; the Hydrocyrius community, where the species Hydrocyrius sp. predominates in Group I, describing stations with low oxygenation and moderate mineralization; and the Lumbriculidae community, where Lumbriculidae is the taxon associated with environments with high mineralization and critical oxygenation. These two methods contribute to the biomonitoring of tropical aquatic environments, firstly by grouping organisms by affinity and then identifying those that reflect the environment conditions. This facilitates the detection of changes in the quality of hydrosystems and guides management and conservation efforts. Full article
(This article belongs to the Special Issue Freshwater Zoobenthos Biodiversity, Evolution and Ecology)
Show Figures

Figure 1

19 pages, 3690 KiB  
Article
Embedded Complexity of Evolutionary Sequences
by Jonathan D. Phillips
Entropy 2024, 26(6), 458; https://doi.org/10.3390/e26060458 - 28 May 2024
Viewed by 1022
Abstract
Multiple pathways and outcomes are common in evolutionary sequences for biological and other environmental systems due to nonlinear complexity, historical contingency, and disturbances. From any starting point, multiple evolutionary pathways are possible. From an endpoint or observed state, multiple possibilities exist for the [...] Read more.
Multiple pathways and outcomes are common in evolutionary sequences for biological and other environmental systems due to nonlinear complexity, historical contingency, and disturbances. From any starting point, multiple evolutionary pathways are possible. From an endpoint or observed state, multiple possibilities exist for the sequence of events that created it. However, for any observed historical sequence—e.g., ecological or soil chronosequences, stratigraphic records, or lineages—only one historical sequence actually occurred. Here, a measure of the embedded complexity of historical sequences based on algebraic graph theory is introduced. Sequences are represented as system states S(t), such that S(t − 1) ≠ S(t) ≠ S(t + 1). Each sequence of N states contains nested subgraph sequences of length 2, 3, …, N − 1. The embedded complexity index (which can also be interpreted in terms of embedded information) compares the complexity (based on the spectral radius λ1) of the entire sequence to the cumulative complexity of the constituent subsequences. The spectral radius is closely linked to graph entropy, so the index also reflects information in the sequence. The analysis is also applied to ecological state-and-transition models (STM), which represent observed transitions, along with information on their causes or triggers. As historical sequences are lengthened (by the passage of time and additional transitions or by improved resolutions or new observations of historical changes), the overall complexity asymptotically approaches λ1 = 2, while the embedded complexity increases as N2.6. Four case studies are presented, representing coastal benthic community shifts determined from biostratigraphy, ecological succession on glacial forelands, vegetation community changes in longleaf pine woodlands, and habitat changes in a delta. Full article
(This article belongs to the Special Issue Entropy and Information in Biological Systems)
Show Figures

Figure 1

Back to TopTop