Diversity

13 pages, 1542 KiB

Open AccessHypothesis

A Hypothesis on Suspension Feeding in Early Chelicerates (Offacolidae)

by Lorenzo Lustri, Luis Collantes, Cristiana J. P. Esteves, Robert J. O’Flynn, Farid Saleh and Yu Liu

Diversity 2025, 17(6), 412; https://doi.org/10.3390/d17060412 (registering DOI) - 11 Jun 2025

Abstract

The Cambrian–Ordovician Plankton Revolution played a crucial role in the Great Ordovician Biodiversification Event (GOBE) or Ordovician Radiation, as a driver of diversification. The emergence of new planktonic species enhanced primary productivity and improved nutrient cycling, fueling diversification across trophic levels. In this [...] Read more.

The Cambrian–Ordovician Plankton Revolution played a crucial role in the Great Ordovician Biodiversification Event (GOBE) or Ordovician Radiation, as a driver of diversification. The emergence of new planktonic species enhanced primary productivity and improved nutrient cycling, fueling diversification across trophic levels. In this context, established plankton consumers like sponges and cnidarians thrived, and animals like euarthropods also radiated in response to these environmental conditions. Here, we hypothesize that Offacolidae, a small group of early chelicerates (the group including sea spiders, spiders, mites, and horseshoe crabs) known from the early Ordovician to the end of the Silurian, were suspension feeders that diversified within this changing ecosystem. Extant chelicerates are primarily predators or parasites, with no known cases of suspension feeding, which is also the case in extinct members. However, anatomical and environmental evidence suggest that Offacolidae may have adopted this feeding strategy. We examine the environmental conditions in which Offacolidae fossils were found, considering both biotic and abiotic factors such as paleolatitude, bathymetry, and the associated plankton community. We also assess the possible biomechanics of their unique appendages to determine their suitability for suspension feeding. Finally, comparisons with extant arthropods, such as the suspension-feeding crustaceans Limnomysis benedeni, Atya gabonensis, Subeucalanus pileatus, and the genus Emerita, provide insights into possible evolutionary analogies in their morphology, which may have served the same function. If confirmed, this hypothesis would make Offacolidae a unique case within chelicerates, illustrating how exceptional early Ordovician conditions fostered novel ecological adaptations and highlighting an interesting case of analogy between different lineages of euarthropods. Full article

(This article belongs to the Topic Problems and Hypotheses in Palaeontology)

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19 pages, 1813 KiB

Open AccessArticle

Lots of Lancelets or Not? Diversity of Cephalochordates in the Tropical Eastern Pacific

by Maycol Ezequiel Madrid Concepcion, Kenneth S. Macdonald III, Amy C. Driskell, Regina Wetzer, Maikon Di Domenico and Rachel Collin

Diversity 2025, 17(6), 411; https://doi.org/10.3390/d17060411 - 10 Jun 2025

Abstract

As close relatives of the vertebrates, cephalochordates have been the focus of significant evo–devo and genomic research; however, their biodiversity and systematics remain poorly known. In particular, few species have been documented in the eastern Pacific and there are few published observations for [...] Read more.

As close relatives of the vertebrates, cephalochordates have been the focus of significant evo–devo and genomic research; however, their biodiversity and systematics remain poorly known. In particular, few species have been documented in the eastern Pacific and there are few published observations for this region. Using sequences from COI and 16S DNA barcode markers and morphological observations from 16 animals collected incidentally during other studies, we document the presence of three species of amphioxus on the Pacific coast and one from the Caribbean coast of Panama. The high genetic diversity recovered from so few samples suggests that the application of molecular taxonomy to neotropical amphioxus would likely uncover additional species and could help to more easily delineate morphological differences among taxa. Full article

(This article belongs to the Special Issue Patterns Of Marine Benthic Biodiversity)

13 pages, 1949 KiB

Open AccessArticle

Population Viability Analysis Revealed the Vulnerability of Yangtze Finless Porpoise (Neophocaena asiaeorientalis) in Poyang Lake

by Bin Wu, Weiping Wang, Yuehua Wang and Zhihong Zhang

Diversity 2025, 17(6), 410; https://doi.org/10.3390/d17060410 - 10 Jun 2025

Abstract

Poyang Lake in China is the most critical habitat and final refuge for the Yangtze finless porpoise (Neophocaena asiaeorientalis), YFP. In 2022, its population reached approximately 492 individuals, an increase of 35 from the 457 individuals recorded in 2017, showing a [...] Read more.

Poyang Lake in China is the most critical habitat and final refuge for the Yangtze finless porpoise (Neophocaena asiaeorientalis), YFP. In 2022, its population reached approximately 492 individuals, an increase of 35 from the 457 individuals recorded in 2017, showing a steady upward trend. The infrequent movement of YFPs between Poyang Lake and the Yangtze River represents a considerable threat to the long-term viability of this population. Additionally, serious water shortages in the lake during the dry season have led the government to consider the establishment of a hydraulic project. Therefore, a reliable risk assessment and quantitative analysis of conservation scenarios are urgently needed for this population. Population viability analysis of the YFP population in Poyang Lake was conducted using the VORTEX software. The baseline model predicted a probability of extinction of 0.241 over the next 100 years, with no probability of extinction in the first 30 years; the genetic diversity would be on a continuous downward trend and decline by 91.5%. The comprehensive protection model predicted a probability of extinction of 0.0028 and that the genetic diversity would be maintained at about 0.996 in 100 years. Breeding rate, sex ratio at birth, mortality rate, and gene flow were the factors that were sensitive to maintaining population viability. The results showed that the population of YFPs in Poyang Lake was at a high risk of extinction due to the decline in genetic diversity and the higher mortality and lower birth rate caused by habitat degradation. A total ban on productive fishing and the rescue and interchange of YFPs are conducive to enhancing the viability of the YFP population in Poyang Lake. Full article

(This article belongs to the Special Issue Wetland Biodiversity and Ecosystem Conservation)

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31 pages, 14206 KiB

Open AccessArticle

Plants Traditionally Used for Making Utility Products by Forest Dwelling Gaddi and Sippi Tribes in Bhaderwah Tehsil of the Union Territory of Jammu and Kashmir, India

by Bhekam Pal Singh, Shivika Sharma, Vikas Sharma, R. K. Manhas and Iyyakkannu Sivanesan

Diversity 2025, 17(6), 409; https://doi.org/10.3390/d17060409 - 10 Jun 2025

Abstract

Tribals are known as the torchbearers of ethnobotany. Traditional plant-derived utility products (PUPs) are environmentally friendly, cost-effective, and easy to handle, and are extensively used by the forest-dwelling Gaddi and Sippi tribes of the Union Territory (UT) of Jammu and Kashmir for their [...] Read more.

Tribals are known as the torchbearers of ethnobotany. Traditional plant-derived utility products (PUPs) are environmentally friendly, cost-effective, and easy to handle, and are extensively used by the forest-dwelling Gaddi and Sippi tribes of the Union Territory (UT) of Jammu and Kashmir for their subsistence. The present study is an attempt to document the invaluable traditional knowledge on wild plants and PUPs possessed by the Gaddi and Sippi tribes before it perishes completely, as this knowledge is transmitted orally to the next generation. Semi-structured schedules were used for the collection of data regarding the method of making and usage of PUPs and the plant species used for making such products. The cultural importance index (CI) and factor informant consensus (F_ic) were calculated to find the predominant plant species and the consensus among informants for species used in making PUPs, respectively. A total of 52 plant species from 28 families and 46 genera are used in the study area for making 93 PUPs. Tools, with a 55.9% contribution, were the major PUP category. Cedrus deodara, used for making 36 PUPs and having a 4.9 CI value, was the most utilized and important tree species for the Gaddi and Sippi tribes. The values of F_ic ranged between 0.97 (miscellaneous PUPs) and 0.99 (containers/storage PUPs). The present study documented 43 plant species as new ethnobotanical records from the UT of Jammu and Kashmir for their use in traditional plant products. The Gaddi and Sippi tribes in the study area have extensive knowledge about forest-based PUPs and the associated plant species. This invaluable knowledge can be exploited for developing new resources for some value-added traditional plant products and agro-based cottage industries, which could play an important role in socio-economic upliftment and livelihood promotion of tribals. Full article

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13 pages, 1394 KiB

Open AccessArticle

Locally Measured Functional Traits Predict Species Registrability in Herbaceous Flora

by Caihong Wei, Si Liu, Xiaoyue Liang, Yingcan Chen, Jiaen Zhang and Ronghua Li

Diversity 2025, 17(6), 408; https://doi.org/10.3390/d17060408 (registering DOI) - 10 Jun 2025

Abstract

Understanding why some plant species become widespread while others remain restricted to limited ranges is a central challenge in ecology and biogeography. This study investigates how functional traits, including morphological, physiological, and nutrient-related traits, relate to the global registrability—defined as the likelihood of [...] Read more.

Understanding why some plant species become widespread while others remain restricted to limited ranges is a central challenge in ecology and biogeography. This study investigates how functional traits, including morphological, physiological, and nutrient-related traits, relate to the global registrability—defined as the likelihood of a species being observed and recorded—for 144 herbaceous plant species from Guangzhou, China. We combined field-measured morphological, physiological, and nutrient-related traits with occurrence data from the Global Biodiversity Information Facility (GBIF), quantified as the number of unique 10 km × 10 km grid cells per species. Our analyses reveal that resource-acquisitive traits—such as high leaf water content, chlorophyll concentration, and photosynthetic capacity—are positively associated with registrability, whereas traits linked to nutrient conservation (e.g., high leaf carbon content and leaf carbon-to-nitrogen ratios) show negative associations. Principal component analysis further indicates that multivariate trait axes characterized by acquisitive strategies are significantly and positively associated with higher registrability. These findings suggest that species with fast-growth, resource-intensive strategies are more likely to be encountered and reported, potentially due to both ecological generalism and observation bias. Full article

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13 pages, 1018 KiB

Open AccessArticle

Nuisance Growth of Cissus verticillata (Vitaceae) Negatively Affects the Structure of Mangroves in Marismas Nacionales Nayarit, Mexico

by Olivia Millán-Aguilar, María Luisa Ordóñez-Rosas, Isaac Castillo-Cruz, Lidia Rodríguez-Arredondo, Marcelino Ruiz-Domínguez, Miguel Ángel Hurtado-Oliva and Marlenne Manzano-Sarabia

Diversity 2025, 17(6), 407; https://doi.org/10.3390/d17060407 - 9 Jun 2025

Abstract

Changes in the structure and composition of mangroves may be influenced by anthropogenic and natural causes. Mangrove coverage in Marismas Nacionales Nayarit –a Biosphere Reserve in northwestern Mexico—has declined in the last decades, mostly related to human activities (e.g., opening of the Cuautla [...] Read more.

Changes in the structure and composition of mangroves may be influenced by anthropogenic and natural causes. Mangrove coverage in Marismas Nacionales Nayarit –a Biosphere Reserve in northwestern Mexico—has declined in the last decades, mostly related to human activities (e.g., opening of the Cuautla inlet) and climate variability (e.g., El Niño Southern Oscillation and hurricanes), leading to diverse ecological and socioeconomic consequences. This contribution reports the impact of Cissus verticillata—a climbing plant species—in the structure of mangroves distributed in this Natural Protected Area during 2019 and 2022. Forest structure analysis was compared in four plots of 20 m × 20 m each, all of them influenced by San Pedro Mezquital river. Two plots (Unión de Corrientes) showed the presence of Cissus verticillata, while two nearby plots (Boca de Camichín) recorded no presence of this species. A poor mangrove structure, no natural seedling recruitment and high mortality was observed in those sites with the presence of C. verticillata. These results highlight the vulnerability of mangroves to C. verticillata in Marismas Nacionales Nayarit Biosphere Reserve, which in addition to other human and climate stressors may compromise its ecological integrity in the future. Full article

(This article belongs to the Special Issue Spatial and Temporal Studies in Marine Protected Areas: Mexican Chapter)

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24 pages, 8206 KiB

Open AccessReview

Description of a New Genus and Species of Semi-Aquatic Rodent (Cricetidae, Sigmodontinae, Ichthyomyini) from the Southern Peruvian Andes

by Horacio Zeballos, Alexánder Pari, César E. Medina, Kateryn Pino, Sandra Arias, Alayda L. Arce and Fiorella N. Gonzales

Diversity 2025, 17(6), 406; https://doi.org/10.3390/d17060406 - 9 Jun 2025

Abstract

We describe a new genus and species of the tribe Ichthyomyini (Rodentia: Sigmodontinae) based on three specimens collected in Machupicchu, Cusco, in the southern Peruvian Andes. Our study includes a comprehensive morphological analysis of 201 specimens representing all recognized species, employing multivariate statistics [...] Read more.

We describe a new genus and species of the tribe Ichthyomyini (Rodentia: Sigmodontinae) based on three specimens collected in Machupicchu, Cusco, in the southern Peruvian Andes. Our study includes a comprehensive morphological analysis of 201 specimens representing all recognized species, employing multivariate statistics (principal component analysis) of external and cranial measurements, as well as phylogenetic methods. We used maximum parsimony for morphological data and concatenated molecular datasets (Cytochrome b [17 species], IRBP [15 species], and RAG1 [11 species]) analyzed via maximum likelihood and Bayesian inference. The new genus and species exhibit an allopatric distribution relative to other Ichthyomyini and are distinguished by the following combination of traits: dull slate-gray dorsal fur, lighter ventrally without contrast to the dorsum; incomplete philtrum; vestigial pinna concealed within head fur; long, broad hindfeet with a well-developed fringe of stiff hairs and brown soles; laterally compressed tail exceeding head-body length; type 1 carotid circulation pattern; absence of the orbicular apophysis of the malleus; presence of posteroloph and posterolophid in M1, M2, m1, and m2; unilocular hemiglandular stomach (non-reduced). Full article

(This article belongs to the Section Animal Diversity)

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16 pages, 5957 KiB

Open AccessArticle

Genetic Diversity, Connectivity and Demographic History of the Small Red Scorpionfish Scorpaena notata at a Small Scale in the Balearic Islands (Western Mediterranean)

by Joan Riera, Adriana Tudurí, Beatriz Guijarro, Francesc Ordines, Antònia Picornell and Sergio Ramírez-Amaro

Diversity 2025, 17(6), 405; https://doi.org/10.3390/d17060405 - 7 Jun 2025

Viewed by 154

Abstract

This study analyses for the first time the genetic diversity, connectivity, and evolutionary dynamics of the small red scorpionfish (Scorpaena notata) in the Balearic Islands, using two mitochondrial DNA markers: Cytochrome c oxidase subunit I (COI) and the Control Region (CR). [...] Read more.

This study analyses for the first time the genetic diversity, connectivity, and evolutionary dynamics of the small red scorpionfish (Scorpaena notata) in the Balearic Islands, using two mitochondrial DNA markers: Cytochrome c oxidase subunit I (COI) and the Control Region (CR). Nucleotide diversity of the COI gene was found to be low compared to other commercial fish species, suggesting that fishing may be impacting the population despite being a by-catch species. In contrast, the CR showed higher genetic variability. Demographic history analyses suggest that S. notata underwent a population expansion during the Pleistocene, possibly driven by sea-level changes. Genetic structure analyses (F_st and AMOVA) indicated genetic homogeneity and high connectivity among the Balearic Islands’ population, likely facilitated by its passive dispersion via pelagic eggs and larvae and the oceanographic conditions of the region. Our results suggest that the entire Balearic Islands could be considered as a unique Management Unit, although its potential relation to other nearby areas, such as the Iberian Peninsula, along with the analysis of additional genetic markers, should be addressed in future studies. Full article

(This article belongs to the Section Marine Diversity)

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12 pages, 938 KiB

Open AccessArticle

Developmental Dynamics of Bacterial Microbiota in Aphis gossypii Revealed Using Full-Length 16S rRNA Sequencing

by Yunchao Wang, Xingmei Xie, Qiuli Hou, Chuying Wei, Zhan Chen, Leilei Fan, E Liang, Zhuo Li and Kun Yang

Diversity 2025, 17(6), 404; https://doi.org/10.3390/d17060404 - 6 Jun 2025

Viewed by 165

Abstract

The cotton aphid, Aphis gossypii, is a globally significant agricultural pest whose microbiota plays vital roles in its physiology and adaptation. However, the dynamics of bacterial communities across its developmental stages remain poorly understood. This study employed full-length 16S rRNA gene sequencing [...] Read more.

The cotton aphid, Aphis gossypii, is a globally significant agricultural pest whose microbiota plays vital roles in its physiology and adaptation. However, the dynamics of bacterial communities across its developmental stages remain poorly understood. This study employed full-length 16S rRNA gene sequencing to characterize the microbiota structure, diversity, and functional potential in nine developmental stages of A. gossypii, including egg, nymph (1-, 3-, 5-, 7-day-old), and adult (1-, 3-, 5-, 7-day-old). Results revealed Proteobacteria (72.75–95.51%) as the dominant phylum across all stages, with Buchnera aphidicola (primary obligate symbiont) constituting over 23.83% of bacterial abundance and peaking in eggs (≈80%). Alpha diversity indices (Shannon, Simpson) indicated significantly higher microbial diversity in nymphs compared to adults, suggesting stage-specific ecological interactions. While beta diversity analysis showed no structural clustering by developmental stage, functional predictions highlighted enrichment in metabolic pathways (>73% of genes), though limitations in 16S-based functional inference were noted. Notably, facultative symbionts like Hamiltonella or Serratia were absent, contrasting with other aphid systems. Dynamic shifts in Buchnera titer and the prominence of Delftia tsuruhatensis and Enterobacter hormaechei implied potential roles in host adaptation. These findings highlight the persistent dominance of the obligate symbiont Buchnera aphidicola across all developmental stages, despite quantitative fluctuations in its abundance, alongside stage-specific shifts in facultative bacterial communities, offering insights into novel targets for microbiome-driven pest management strategies. Further multi-omics approaches are warranted to validate functional contributions of these microbial communities. Full article

(This article belongs to the Section Microbial Diversity and Culture Collections)

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22 pages, 17218 KiB

Open AccessArticle

Gliding on the Edge: The Impact of Climate Change on the Habitat Dynamics of Two Sympatric Giant Flying Squirrels, Petaurista elegans and Hylopetes phayrei, in South and Southeast Asia

by Imon Abedin, Manokaran Kamalakannan, Dhriti Banerjee, Hyun-Woo Kim, Hilloljyoti Singha and Shantanu Kundu

Diversity 2025, 17(6), 403; https://doi.org/10.3390/d17060403 - 6 Jun 2025

Viewed by 114

Abstract

South and Southeast Asia are considered biodiversity hotspots, yet they face escalating threats from deforestation and climate change. This study evaluates the suitable habitat extent of two sympatric flying squirrels, Petaurista elegans and Hylopetes phayrei, using ensemble distribution models based on the [...] Read more.

South and Southeast Asia are considered biodiversity hotspots, yet they face escalating threats from deforestation and climate change. This study evaluates the suitable habitat extent of two sympatric flying squirrels, Petaurista elegans and Hylopetes phayrei, using ensemble distribution models based on the climate-only model (COM) and habitat–climate model (HCM) approaches. The results indicated severe habitat loss, with suitable areas comprising only 1.56–1.66% (P. elegans) and 0.22–2.47% (H. phayrei) of their estimated extent of occurrence. Within IUCN-defined ranges, the suitability for P. elegans was 28.25% and 30.04%, while H. phayrei showed 2.86% and 32.39% in terms of the HCM and COM, respectively. The analysis further revealed habitat fragmentation, reduced patch size, and edge complexity, with future scenarios predicting increased isolation. These results highlight the urgent necessity for region-specific conservation strategies focusing on habitat recovery, connectivity, and transboundary cooperation. The recommended actions include genetic studies, corridor analysis, and field validation. This research provides critical baseline data to inform integrated, multi-stakeholder conservation planning across South and Southeast Asia for the long-term persistence of these vulnerable flying squirrel species. Full article

(This article belongs to the Special Issue 15th Anniversary of Diversity—Biodiversity, Conservation and Ecology of Animals, Plants and Microorganisms)

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20 pages, 1518 KiB

Open AccessArticle

Research Trends and Hotspots in eDNA-Based Surveys of Macroinvertebrates: A Bibliometric Analysis

by Xinyu Ge, Junyu Zhang, Ziming Shao, Lu Chai, Jiaxin Nie, Dan Yin, Haoran Zhang, Wenbin Liu and Chuncai Yan

Diversity 2025, 17(6), 402; https://doi.org/10.3390/d17060402 - 6 Jun 2025

Viewed by 92

Abstract

Environmental DNA metabarcoding offers an efficient and non-invasive solution for aquatic biomonitoring surveys, particularly demonstrating remarkable potential in macroinvertebrate research. In this study, we systematically analyzed 322 articles in the Web of Science Core Collection from 2010 to 2024 using bibliometric methods to [...] Read more.

Environmental DNA metabarcoding offers an efficient and non-invasive solution for aquatic biomonitoring surveys, particularly demonstrating remarkable potential in macroinvertebrate research. In this study, we systematically analyzed 322 articles in the Web of Science Core Collection from 2010 to 2024 using bibliometric methods to reveal the research trends and technological advances in the field of macroinvertebrate surveys based on eDNA metabarcoding technology. The results showed that the number of annual publications has increased rapidly since 2012, with the United States (n = 58), France (n = 43), and Canada (n = 39) as the main contributing countries, and the most intensive collaboration network was observed among Europe countries. A keyword analysis shows that, in the past five years, the research direction has shifted to novel methodologies including multi-marker approaches, quantitative PCR, digital PCR, and other molecular detection platforms and high-throughput sequencing technology, with the integration of machine-learning and deep-learning architecture significantly improving the taxonomic resolution of data analysis. Despite the advantages of eDNA metabarcoding technology in terms of sensitivity and efficiency, persistent challenges including false positives/negatives in detection and incomplete reference databases are still the main challenges. This study provides methodological evidence for standardizing eDNA protocols in benthic assessments while identifying critical knowledge gaps. Full article

(This article belongs to the Section Animal Diversity)

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20 pages, 3005 KiB

Open AccessArticle

Pathways to 30 × 30: Evidence-Based Lessons from Global Case Studies in Biodiversity Conservation

by Susmita Dasgupta, David Wheeler and Brian Blankespoor

Diversity 2025, 17(6), 401; https://doi.org/10.3390/d17060401 - 6 Jun 2025

Viewed by 189

Abstract

The global 30 × 30 initiative, endorsed by 188 countries, aims to expand terrestrial and marine protected areas to cover 30% of the planet by 2030. This study utilizes newly available species-occurrence maps from the Global Biodiversity Information Facility (GBIF) to identify conservation [...] Read more.

The global 30 × 30 initiative, endorsed by 188 countries, aims to expand terrestrial and marine protected areas to cover 30% of the planet by 2030. This study utilizes newly available species-occurrence maps from the Global Biodiversity Information Facility (GBIF) to identify conservation priorities in 10 countries across Latin America (Brazil, Costa Rica, and Ecuador), Africa (Cameroon, South Africa, and Madagascar), and the Asia–Pacific region (Papua New Guinea, Philippines, India, and China). By incorporating diverse taxa—including vertebrates, invertebrates, and plants—the analysis ensures equitable species representation in conservation planning. A spatial prioritization algorithm is employed to pinpoint areas where new protected regions can address biodiversity gaps, with a particular focus on endemic and unprotected species. The results highlight significant variation in initial conservation conditions, including existing protection levels and spatial distribution of unprotected species. Countries with high spatial clustering of unprotected species achieve substantial protection gains with modest protected-area expansions, while others may require exceeding the 30% target to ensure comprehensive biodiversity coverage. The study underscores the importance of localized conservation strategies within the broader global framework, demonstrating how targeted spatial planning can enhance biodiversity outcomes and support the equitable implementation of the 30 × 30 commitment. Full article

(This article belongs to the Special Issue Restoring and Conserving Biodiversity: A Global Perspective)

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15 pages, 1597 KiB

Open AccessArticle

Different Ribotypes of Akashiwo sanguinea Harbor Distinct Bacterial Communities in Their Phycospheres

by Hanying Zou, Fengting Li, Jiaqi Lu, Zhangxi Hu, Lixia Shang, Ying Zhong Tang and Yunyan Deng

Diversity 2025, 17(6), 400; https://doi.org/10.3390/d17060400 - 5 Jun 2025

Viewed by 199

Abstract

The unarmored dinoflagellate Akashiwo sanguinea is a cosmopolitan harmful algal species known for forming intense blooms leading to mass mortality of fish, shellfish, and seabirds. Globally distributed populations of A. sanguinea have been classified into four ribotypes based on their characteristic sequences in [...] Read more.

The unarmored dinoflagellate Akashiwo sanguinea is a cosmopolitan harmful algal species known for forming intense blooms leading to mass mortality of fish, shellfish, and seabirds. Globally distributed populations of A. sanguinea have been classified into four ribotypes based on their characteristic sequences in LSU rRNA gene and primary geographic distributions. In this study, we compared the bacterial communities co-existing with the six strains of A. sanguinea from China and the USA (belonging to two ribotypes) using high-throughput sequencing of 16S rRNA gene amplicons. Generally, a bacterial microbiome with high diversity was found to be associated with laboratory-cultured A. sanguinea strains from different geographic origins. Based on ribotype classification, the six samples were divided into two groups (ribotype A: AsCHINA; ribotype C: AsUSA) for subsequent comparative analyses of their bacterial communities. Beta diversity analysis revealed a clear separation between the two groups, reflecting significant differences in bacterial community composition between the two ribotypes. Significantly higher abundance of nitrogen-fixing bacteria was found in the AsUSA group, suggesting that ribotype C may benefit from external nitrogen sources provided by their bacterial associates. If this also holds true in natural environments, this nitrogen-fixing partnership likely confers a competitive advantage to ribotype C in oligotrophic offshore waters, and potentially extends bloom duration when environmental nitrogen is depleted. Our study raised the possibility that different ribotypes of A. sanguinea may harbor distinct prokaryotic microbiomes in their phycospheres under stable cultivation conditions. Further comprehensive comparison among more isolates across all four ribotypes is highly necessary to validate this hypothesis. Full article

(This article belongs to the Special Issue Phytoplankton Communities and Their Microbial Associates Under Climate Change and Anthropogenic Pressures)

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16 pages, 1312 KiB

Open AccessArticle

Utilizing Remote Sensing Data for Species Distribution Modeling of Birds in Croatia

by Andreja Radović, Sven Kapelj and Louie Thomas Taylor

Diversity 2025, 17(6), 399; https://doi.org/10.3390/d17060399 - 5 Jun 2025

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Abstract

Accurate information on species distributions and population sizes is essential for effective biodiversity conservation, yet such data are often lacking at national scales. This study addresses this gap by assessing the distribution and abundance of 111 bird species across Croatia, including breeding, wintering, [...] Read more.

Accurate information on species distributions and population sizes is essential for effective biodiversity conservation, yet such data are often lacking at national scales. This study addresses this gap by assessing the distribution and abundance of 111 bird species across Croatia, including breeding, wintering, and migratory flyway populations. We combined Species Distribution Models (SDMs) with expert-based population estimates to generate spatially explicit predictions. The modeling framework incorporated high-resolution Earth observation (EO) data and advanced spatial analysis techniques. Environmental variables, such as land cover, were derived from satellite datasets, while climate variables were interpolated from ground measurements and refined using EO-based co-variates. Model calibration and validation were based on species occurrence records and EO-derived predictors. This integrative approach enabled both national-scale population estimates and fine-scale habitat assessments. The results identified critical habitats, population hotspots, and areas likely to experience distribution shifts under changing environmental conditions. By integrating EO data with expert knowledge, this study enhances the robustness of population estimates, particularly where species monitoring data are incomplete. The findings support conservation prioritization, inform land use and resource management, and contribute to long-term biodiversity monitoring. The methodology is scalable and transferable, offering a practical framework for ecological assessments in diverse regions. We integrated expert-based population estimates with species distribution models (SDMs) by applying expert-derived density values to areas of suitable habitat predicted by SDMs. This approach enables spatially explicit population estimates by combining ecological modeling with expert knowledge, which is particularly useful in systems with limited data. Experts provided species-specific density estimates stratified by habitat type, seasonality, behavior, and detectability, aligned with habitat suitability classes derived from SDM outputs. Full article

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6 pages, 3550 KiB

Open AccessInteresting Images

Peculiar Morphology of Montipora millepora Reveals Interspecific Competition for Space Among Two Other Major Foundation Species in Jeju Waters, South Korea

by Anna B. Jöst, Garance Perrois, Leonard Pons, Sun Kyeong Choi, Seonggil Go and Taihun Kim

Diversity 2025, 17(6), 398; https://doi.org/10.3390/d17060398 - 5 Jun 2025

Viewed by 248

Abstract

An atypical surface shape was observed in encrusting coral colonies of Montipora millepora. Initial assumptions on their origin focused on the presence of epibiotic intermediate habitat formers, such as coral-dwelling and -boring organisms. However, further investigations revealed their origin to also be [...] Read more.

An atypical surface shape was observed in encrusting coral colonies of Montipora millepora. Initial assumptions on their origin focused on the presence of epibiotic intermediate habitat formers, such as coral-dwelling and -boring organisms. However, further investigations revealed their origin to also be substrate shape-related, prompted by overgrowing other foundation species. The unusual bumps stemmed from encrusting over specimens of the coral Alveopora japonica, and the forked, tube-like structures over holdfasts of the brown alga Ecklonia cava. Spatial distribution patterns and interspecific competition are briefly reviewed. Potential effects of morphological changes for Montipora species identification, as well as implications of altered topography in general, are mentioned. Full article

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16 pages, 4506 KiB

Open AccessArticle

Where Endemism Meets Urgency: Native Cactaceae and the Conservation Crisis in the Subtropical South America Pampa

by Alessandra Almeida de Menezes, Eugenia Jacira Bolacel Braga and João Iganci

Diversity 2025, 17(6), 397; https://doi.org/10.3390/d17060397 - 4 Jun 2025

Viewed by 234

Abstract

The subtropical grasslands of South America are known as Pampa, span parts of Brazil, Uruguay, and Argentina, and are undergoing rapid and alarming transformations due to agricultural expansion, habitat fragmentation, and climate change. Despite this, these areas harbor a remarkable diversity of Cactaceae, [...] Read more.

The subtropical grasslands of South America are known as Pampa, span parts of Brazil, Uruguay, and Argentina, and are undergoing rapid and alarming transformations due to agricultural expansion, habitat fragmentation, and climate change. Despite this, these areas harbor a remarkable diversity of Cactaceae, including a high proportion of endemic and threatened species. This study offers the first comprehensive inventory of native and endemic cactus taxa in the Pampean province of the Chacoan domain, integrating data from georeferenced herbarium records, biodiversity databases, and fieldwork. A total of 111 native taxa were identified, of which 62% are endemic to the region. Spatial analyses reveal that many species occur outside protected areas, with hotspots of richness and endemism located near international borders and in poorly studied regions. These findings underscore the urgent need to reassess conservation priorities in Pampa, where biodiversity is being lost at an accelerating pace. By identifying critical areas for conservation and highlighting gaps in species assessments, the present study contributes essential data to support public policy, conservation planning, and the establishment of cross-border strategies for the protection of this unique and vulnerable flora. Full article

(This article belongs to the Section Biodiversity Conservation)

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1 pages, 127 KiB

Open AccessCorrection

Correction: Eimanifar et al. Using ISSR Genomic Fingerprinting to Study the Genetic Differentiation of Artemia Leach, 1819 (Crustacea: Anostraca) from Iran and Neighbor Regions with the Focus on the Invasive American Artemia franciscana. Diversity 2020, 12, 132

by Amin Eimanifar, Alireza Asem, Pei-Zheng Wang, Weidong Li and Michael Wink

Diversity 2025, 17(6), 396; https://doi.org/10.3390/d17060396 - 4 Jun 2025

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Abstract

In the published publication [...] Full article

(This article belongs to the Section Animal Diversity)

16 pages, 703 KiB

Open AccessArticle

Genetic Testing of a High-End ‘Angel Skin’ Precious Coral Necklace Identifies a Species New to the Precious Coral Trade and Potentially New to Science

by Bertalan Lendvay, Laurent E. Cartier, Akitsugu Sato, Michael S. Krzemnicki, Masanori Nonaka, Nina Yasuda, Kenji Takata, Takeshi Hayashibara, Nadja V. Morf and Nozomu Iwasaki

Diversity 2025, 17(6), 395; https://doi.org/10.3390/d17060395 - 3 Jun 2025

Viewed by 188

Abstract

Precious corals from the Corallidae family (Corallium, Hemicorallium, and Pleurocorallium genera) are well known in the high-end jewelry industry due to their colorful and durable axial skeleton. They exist in various colors from white to pink to dark red. One [...] Read more.

Precious corals from the Corallidae family (Corallium, Hemicorallium, and Pleurocorallium genera) are well known in the high-end jewelry industry due to their colorful and durable axial skeleton. They exist in various colors from white to pink to dark red. One highly appreciated shade is the light pink color, the so-called ‘angel skin’. This color is most often associated with Pleurocorallium elatius and Pleurocorallium secundum, species listed in CITES Appendix III. However, this has been based on an assumption of their visual similarity and has never been underpinned by detailed morphologic or genetic data. In this study, we present the analysis of an ‘angel skin’ coral necklace of exceptional size and homogeneous color and quality. Visual observation and Raman spectroscopy confirmed that the necklace consists of genuine, untreated precious coral material. Following minimally destructive sampling, respectively, drilling 2.2, 2.4, and 2.4 milligrams of material from the existing drill-holes, three randomly selected beads from the necklace were subject to a routine genetic identification assay, which is based on sequencing a short, taxonomically informative mitochondrial region. This genetic analysis identified the coral material as not from P. elatius or P. secundum but from another Pleurocorallium species. We subsequently sequenced additional mitochondrial DNA fragments from one ‘angel skin’ coral bead and compared them against a well-represented, curated reference data set of Pleurocorallium, including the first-ever sequencing of Pleurocorallium gotoense, Pleurocorallium johnsoni, Pleurocorallium cf. pusillum, and Pleurocorallium uchidai. We concluded that the analyzed material of the ‘angel skin’ coral necklace belongs to the Pleurocorallium norfolkicum species complex but is not identical to any hitherto analyzed and published Pleurocorallium specimens. A comparison with further taxonomically unidentified precious coral colony fragments identified a single sample fished in Vietnam to be completely identical to the ‘angel skin’ coral bead in the studied DNA regions. Thus, by the analysis of a high-end jewel, we discovered a species new to the jewelry trade and potentially also unknown to science. This implies that the currently considered list of species present in the precious coral trade is incomplete. Full article

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15 pages, 3610 KiB

Open AccessArticle

Diversity of Color in Pleasing Fungus Beetles (Coleoptera: Erotylidae: Erotylinae)

by Rachel J. Sutherland, Eva J. Driggs, Laura N. Sutherland, Paul E. Skelley, Seth M. Bybee and Gareth S. Powell

Diversity 2025, 17(6), 394; https://doi.org/10.3390/d17060394 - 3 Jun 2025

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Abstract

Erotylidae, or pleasing fungus beetles, are a morphologically diverse lineage of Coleoptera notable for the variety of colors and patterns present on their dorsal surface. This study begins the characterization of this diversity and discusses patterns around coloration within Erotylinae. Using spectrophotometer data, [...] Read more.

Erotylidae, or pleasing fungus beetles, are a morphologically diverse lineage of Coleoptera notable for the variety of colors and patterns present on their dorsal surface. This study begins the characterization of this diversity and discusses patterns around coloration within Erotylinae. Using spectrophotometer data, we investigated the frequency of certain color motifs across erotyline tribes and discuss geographic patterns in these color motifs. The most frequently observed colors within Erotylinae are brown/black with orange/red maculations in the case of bicolored taxa. In terms of type of maculations, stripes were the most common pattern observed. When summarizing the diversity across major geographic areas, the Neotropical and Indomalay regions displayed the most color variation, followed by the Australasian region. Full article

(This article belongs to the Special Issue Diversity, Distribution and Zoogeography of Coleoptera)

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15 pages, 21880 KiB

Open AccessArticle

Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania

by Ionuț Grădianu, Kenneth A. Monsch and Dorin Sorin Baciu

Diversity 2025, 17(6), 393; https://doi.org/10.3390/d17060393 - 31 May 2025

Viewed by 235

Abstract

This study revises †Palaeorhynchidae (Istiophoriformes), a rare and taxonomically disputed group within Romania’s Oligocene ichthyofauna. Historically placed within Scombroidei, Istiophoriformes is now supported by molecular phylogenetics as a distinct lineage. However, prior Romanian fossil descriptions, often fragmentary, require critical revision to resolve their [...] Read more.

This study revises †Palaeorhynchidae (Istiophoriformes), a rare and taxonomically disputed group within Romania’s Oligocene ichthyofauna. Historically placed within Scombroidei, Istiophoriformes is now supported by molecular phylogenetics as a distinct lineage. However, prior Romanian fossil descriptions, often fragmentary, require critical revision to resolve their phylogeny, ecology, and biogeography. Outdated classifications must align with modern systematics. Our analysis confirms only two valid istiophoriform taxa in Romania’s Oligocene: †Homorhynchus colei, previously misassigned to †Palaeorhynchus longirostris or †P. glarisianus, and †Palaeorhynchus humorensis. This clarifies long-standing taxonomic uncertainties and underscores the need for integrative approaches in paleoichthyology. The findings refine regional Oligocene biodiversity records and highlight the Eastern Carpathians’ significance in understanding marine ecosystems of the epoch. Full article

(This article belongs to the Special Issue Diversity, Biogeography and Evolution of Actinopterygians)

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25 pages, 6375 KiB

Open AccessArticle

Collections for the Public Good: A Case Study from Ohio

by Loren E. Babcock, Daniel F. Kelley, John B. Krygier, William I. Ausich, David L. Dyer, Dale M. Gnidovec, Anne M. Grunow, D. Mark Jones, Erica Maletic, Camilla Querin, H. Gregory McDonald and D. Joseph Wood

Diversity 2025, 17(6), 392; https://doi.org/10.3390/d17060392 - 31 May 2025

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Abstract

Natural history collections serve science and society in a variety of ways. Collections of geological, including paleontological, materials are of special importance in the 21st century, as they serve not only as repositories for scientific research specimens, but are also used in teaching, [...] Read more.

Natural history collections serve science and society in a variety of ways. Collections of geological, including paleontological, materials are of special importance in the 21st century, as they serve not only as repositories for scientific research specimens, but are also used in teaching, outreach, and engaging the public in science. These collections link us to our scientific, technological, and cultural history, and help to inspire the next generations of scientists and technologists. In addition, they provide inspiration for creative works. They also have an important role in informing public policy and national security, as geological materials are fundamental to the global economy. Examples from universities, museums, and government agencies in central Ohio, USA, help to illustrate the myriad ways that geological collections are relevant to modern society, and provide continuing, critical benefits. These examples reinforce the need to ensure the long-term support of collections. Full article

(This article belongs to the Special Issue Do We Still Need Natural History Collections?)

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16 pages, 2857 KiB

Open AccessArticle

Comparative Plastomics of Tropidia (Orchidaceae): Unraveling Structural Evolution and Phylogenetic Implications in Epidendroideae

by Deng-Li Yu, Zi-Qing Wei, Rong-Rong Yan, Shi-Peng Fei, Wei Wu and Guo-Xiong Hu

Diversity 2025, 17(6), 391; https://doi.org/10.3390/d17060391 - 31 May 2025

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Abstract

Tropidia, a type genus of Tropidieae (Orchidaceae, Epidendroideae), represents an important lineage for investigating plastome evolution and phylogenetic relationships within Epidendroideae. Despite its importance, the lack of available plastid genomic data has hindered comprehensive analyses of its genome structure and phylogenetic relationships. [...] Read more.

Tropidia, a type genus of Tropidieae (Orchidaceae, Epidendroideae), represents an important lineage for investigating plastome evolution and phylogenetic relationships within Epidendroideae. Despite its importance, the lack of available plastid genomic data has hindered comprehensive analyses of its genome structure and phylogenetic relationships. In this study, we assembled and characterized the complete plastid genomes of Tropidia angulosa and T. nipponica, providing valuable insights into plastome evolution and phylogenetic placement of Tropidieae. The plastomes of T. angulosa and T. nipponica exhibited a highly conserved quadripartite structure, sharing similar genomic size (161,395 bp and 160,801 bp) and GC content (36.87% and 36.90%). Both plastomes contained identical gene content and gene order, with 79 protein-coding genes (PCGs), 30 tRNA genes, and four rRNA genes. A total of 169 simple-sequence repeats (SSRs) and 92 long-sequence repeats (LSRs) were identified, most of which were distributed in large single-copy (63.91% and 66.30%) and non-coding regions (83.43% and 65.22%). Comparative plastomes analyses revealed the overall structural stability among photosynthetic lineages, whereas structural variation was primarily detected in mycoheterotrophic lineages. Phylogenomic reconstruction based on plastid-coding sequences revealed that Tropidieae occupies a relatively isolated phylogenetic position within Epidendroideae. These findings contribute to a more comprehensive understanding of plastome evolution and the phylogenetic framework of Epidendroideae. Full article

(This article belongs to the Section Phylogeny and Evolution)

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13 pages, 1153 KiB

Open AccessArticle

Phylogeography and Past Distribution of Peripheral Individuals of Large Hairy Armadillo Chaetophractus villosus

by Aldo Arriagada, Cristian B. Canales-Aguirre, Norka Fuentes, Cristián Saucedo and Nelson Colihueque

Diversity 2025, 17(6), 390; https://doi.org/10.3390/d17060390 - 30 May 2025

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Abstract

The fossil and molecular evidence suggests that the area of origin of the Hairy Armadillo Chaetophractus villosus was the central Pampas region of Argentina, with a current distribution that includes Bolivia, Paraguay and Chile. We studied the evolutionary history of peripheral individuals of [...] Read more.

The fossil and molecular evidence suggests that the area of origin of the Hairy Armadillo Chaetophractus villosus was the central Pampas region of Argentina, with a current distribution that includes Bolivia, Paraguay and Chile. We studied the evolutionary history of peripheral individuals of C. villosus using phylogeographic approaches and potential distribution models for the Holocene. We sequenced a segment of the mitochondrial DNA control region in 22 individuals with a peripheral distribution that inhabit the western limit of its current distribution in Chile, which was compared with Argentine sequences of the central distribution. The results show that the peripheral individuals studied have less genetic polymorphism than populations in the central distribution. All Chilean sequences were grouped in the haplotype C, which is dominant in Patagonian populations of Argentina. The potential distribution model predicts that during the Holocene the areas in which the peripheral populations of Chilean C. villosus are currently distributed presented medium–high habitability conditions for the species. Our results are consistent with the center–periphery model, showing a decrease in genetic diversity in peripheral areas of the distribution of C. villosus. It is probable that the low genetic diversity of the peripheral population is related to recent population establishment by dispersion from adjacent Argentine Patagonian populations. Peripheral populations such as those studied can have small population sizes; however, they can remain stable and have high survival rates during climatic oscillations, acting as important relics for the conservation and evolutionary potential of the species. Full article

(This article belongs to the Special Issue Ecology, Behavior, and Conservation of Armadillos)

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65 pages, 5560 KiB

Open AccessArticle

Mobility Confers Resilience in Red Kangaroos (Osphranter rufus) to a Variable Climate and Coexisting Herbivores (Sheep, Goats, Rabbits and Three Sympatric Kangaroo Species) in an Arid Australian Rangeland

by David B. Croft and Ingrid Witte

Diversity 2025, 17(6), 389; https://doi.org/10.3390/d17060389 - 30 May 2025

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Abstract

In a 1975 review, red kangaroos in the arid rangelands of Australia were said to be favoured with an anomalous prosperity following the introduction of ruminant livestock. In the western and central locations reviewed, this was not sustained, but in the sheep rangelands [...] Read more.

In a 1975 review, red kangaroos in the arid rangelands of Australia were said to be favoured with an anomalous prosperity following the introduction of ruminant livestock. In the western and central locations reviewed, this was not sustained, but in the sheep rangelands of Southern Australia, it is often claimed that such prosperity continues. Here, as elsewhere, the marsupial herbivore guild (kangaroos, wallabies, bettongs and bandicoots) has been simplified by the extinction of the smaller species (the anomaly), while large kangaroos remain abundant. However, the mammalian herbivore guild has gained complexity with not only the introduction of managed ruminant livestock, some of which run wild, but also game like rabbits. We studied the population dynamics, habitat selection and individual mobility of red, western and eastern grey kangaroos, common wallaroos, Merino sheep, feral goats and European rabbits at Fowlers Gap Station in far northwestern New South Wales, Australia. This site is representative of the arid chenopod (Family: Chenopodiaceae) shrublands stocked with sheep, where sheep and red kangaroos dominate the mammalian herbivores by biomass. The study site comprised two contiguous pairs of stocked and unstocked paddocks: a sloping run-off zone and a flat run-on zone, covering a total area of 2158 ha. This three-year study included initial rain-deficient (drought) months followed by more regular rainfall. Red kangaroos showed avoidance of sheep when given the opportunity and heightened mobility in response to localized drought-breaking storms and dispersion of the sheep flock at lambing. Western grey kangaroos were sedentary and did not dissociate from sheep. These effects were demonstrated at the population level and the individual level through radio-tracking a small cohort of females. The other kangaroo species and goats were transient and preferred other habitats. Rabbits were persistent and localized without strong interactions with other species. The results are discussed with a focus on the red kangaroo and some causes for its resilience in the sheep rangelands. Full article

(This article belongs to the Special Issue Ecology, Evolution and Conservation of Marsupials)

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43 pages, 2483 KiB

Open AccessArticle

IT Challenges in Designing and Implementing Online Natural History Collection Systems

by Marcin Lawenda and Paweł Wolniewicz

Diversity 2025, 17(6), 388; https://doi.org/10.3390/d17060388 - 30 May 2025

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Abstract

Numerous institutions engaged in the management of Natural History Collections (NHC) are embracing the opportunity to digitise their holdings. The primary objective is to enhance the accessibility of specimens for interested individuals and to integrate them into the global community by contributing to [...] Read more.

Numerous institutions engaged in the management of Natural History Collections (NHC) are embracing the opportunity to digitise their holdings. The primary objective is to enhance the accessibility of specimens for interested individuals and to integrate them into the global community by contributing to an international specimen database. This initiative demands a comprehensive digitisation process and the development of an IT infrastructure that adheres to stringent functionality, reliability, and security standards. This endeavour focuses on the procedural and operational dimensions associated with accurately storing and managing taxonomic, biogeographic, and ecological data about biological specimens digitised within a conventional NHC framework. The authors suggest categorising the IT challenges into four distinct areas: requirements, digitisation, design, and technology. Each category discusses several selected topics, highlighting often underestimated essentials for implementing the NHC system. The presented analysis is supported by numerous examples of specific implementations, enabling a better understanding of the given topic. This document serves as a resource for teams developing their systems for online collections, offering post factum insights derived from implementation experiences. Full article

(This article belongs to the Special Issue Digitization of Natural History Collections for Biodiversity Science and Conservation)

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9 pages, 195 KiB

Open AccessArticle

Effects of Lead Exposure in Wild Birds as Causes for Incidents and Fatal Injuries

by Ivanka Lazarova and Gergana Balieva

Diversity 2025, 17(6), 387; https://doi.org/10.3390/d17060387 - 30 May 2025

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Abstract

Lead is among the most toxic heavy metals, posing significant risks to all living organisms. It is a pervasive and persistent contaminant in the environment. Ingested lead in birds and wildlife induces a range of sublethal effects that disrupt physiological functions and behavior, [...] Read more.

Lead is among the most toxic heavy metals, posing significant risks to all living organisms. It is a pervasive and persistent contaminant in the environment. Ingested lead in birds and wildlife induces a range of sublethal effects that disrupt physiological functions and behavior, ultimately resulting in mortality at higher doses or with prolonged exposure. To investigate the relation of lead to accidents and injuries in wild birds, we analyzed lead concentration in 43 wild birds that were admitted as patients to the Wildlife Rehabilitation and Breeding Center (WRBC). The findings reveal a significant dependency between the detected levels of lead in the birds’ bone samples and the reported etiology of their injuries, with variances in the age groups of the patients received at the WRBC in Bulgaria. Full article

13 pages, 1827 KiB

Open AccessArticle

Response of the Invasive Cyanobacterium Raphidiopsis raciborskii to Iron and Phosphorus Concentrations in the Habitat: Effects on Growth and Cellular Phosphorus Distribution

by Wenting Shen, Han Yang, Gaibian Ding, Bo Li, Xin Gan, Zijie Yuan, Liqing Wang and Wei Zhang

Diversity 2025, 17(6), 386; https://doi.org/10.3390/d17060386 - 30 May 2025

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Abstract

Harmful Raphidiopsis raciborskii blooms threaten aquatic ecosystems via toxin production, hypoxia induction, and biodiversity loss. To elucidate the synergistic regulatory mechanisms of Fe³⁺ and phosphorus (P) in cyanobacterial growth, we used a sterile pure culture system under laboratory conditions. We set different [...] Read more.

Harmful Raphidiopsis raciborskii blooms threaten aquatic ecosystems via toxin production, hypoxia induction, and biodiversity loss. To elucidate the synergistic regulatory mechanisms of Fe³⁺ and phosphorus (P) in cyanobacterial growth, we used a sterile pure culture system under laboratory conditions. We set different phosphorus sources (organic phosphorus and inorganic phosphorus) and low phosphorus concentration of R. raciborskii culture medium for culture, and set different Fe³⁺ addition amount to determine the basic growth index of cyanobacteria cells and the phosphorus content of different components. The results revealed that under conditions of sufficient inorganic phosphorus, there was a logarithmic relationship between ferric ammonium citrate (Fe³⁺) and the specific growth rate of R. raciborskii. Fe³⁺ > 2 mg/L enhanced IPS enrichment and biomass accumulation. However, in oligotrophic or mesotrophic environments with low inorganic phosphorus concentrations, the effect of Fe³⁺ on the growth of R. raciborskii contrasted with that observed in high-IP (eutrophic) environments, exhibiting a pattern of ‘low promotion and high inhibition’. Under organic phosphorus conditions, R. raciborskii converted phosphorus by increasing alkaline phosphatase activity (APA), but this metabolic compensation failed to restore physiological functions, resulting in growth suppression and enhanced cellular phosphorus reserves. Our results establish quantitative linkages between Fe³⁺-P co-limitation thresholds and algal adaptive responses, providing mechanistic insights for controlling bloom dynamics through targeted manipulation of Fe-P bioavailability. Full article

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14 pages, 1596 KiB

Open AccessArticle

In Situ Investigation of Ecological and Molecular Stress Mechanisms Triggered by Marine Heat Waves in Adriatic Populations of the Mediterranean Mussel

by Martina Capriotti, Luca Bracchetti, Paolo Cocci, Valentina Mazzocchi, Massimiliano Fazzini, Francesco Corvaro and Francesco Alessandro Palermo

Diversity 2025, 17(6), 385; https://doi.org/10.3390/d17060385 - 30 May 2025

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Abstract

Global warming is influencing marine dynamics, with marine heat waves (MHWs) threatening the survival of several species. After observing mussels’ massive mortality for three consecutive years (2022–2024) along the Italian Mid-Adriatic Coast, the present study aimed to evaluate, from an ecological and molecular [...] Read more.

Global warming is influencing marine dynamics, with marine heat waves (MHWs) threatening the survival of several species. After observing mussels’ massive mortality for three consecutive years (2022–2024) along the Italian Mid-Adriatic Coast, the present study aimed to evaluate, from an ecological and molecular perspective, the evolution of the health state of the Mediterranean mussel (Mytilus galloprovincialis) population facing the effects of summer heatwave in 2024, in situ. Three MHWs were recorded over the summer, with the second being 41 days long and having temperatures higher than 30 °C. In both sites considered (at the Tronto River mouth and the Frana San Nicola) inside the Piceno coast, the mussel beds experienced a clear decrease in individual density from April (the reference month) to August, with the total mortality recorded in September. The transcriptional levels of the molecular biomarkers analyzed during this time span revealed a state of heat stress with HSP70 (heat shock protein 70) and HSP90 (heat shock protein 90) upregulated in July and August. The apoptotic signal measured through the branchial transcript quantification of p53 and caspase 3 is less clear. The occurrence of MHWs is reshaping the local macrozoobenthonic community structure: the permanent mussel beds that characterized the intertidal and shallow submerged reef along the Mid-Adriatic coast are shifting to a temporary population that renovates yearly. Full article

(This article belongs to the Special Issue Climate Change Impacts on Marine Biodiversity: From Organisms to Populations and Ecosystems)

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18 pages, 2058 KiB

Open AccessArticle

Tridacna maxima ‘Rediscovered’ in the Eastern Indian Ocean

by Lisa Kirkendale, Peter Middelfart and Michael Amor

Diversity 2025, 17(6), 384; https://doi.org/10.3390/d17060384 - 29 May 2025

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Abstract

Giant clams are ecologically important coral reef animals, with many species facing imminent local extinction. While many regions have undertaken recent assessments of their biodiversity assets, persistent gaps remain even in otherwise well-surveyed areas. This study sought to understand the geographic distribution of [...] Read more.

Giant clams are ecologically important coral reef animals, with many species facing imminent local extinction. While many regions have undertaken recent assessments of their biodiversity assets, persistent gaps remain even in otherwise well-surveyed areas. This study sought to understand the geographic distribution of smaller-bodied and morphologically similar giant clams, specifically Tridacna maxima and T. noae, in the eastern Indian Ocean. Due to the difficulties in reliably identifying these species using morphological characters, we confirmed species identity and investigated intraspecific variation using sequence data from the mitochondrial cytochrome C oxidase subunit I gene (COI). Seventy whole animal vouchers were newly sampled from a 1500 km span of remote northwestern Australian coastline over a decade, as part of an ongoing coral reef survey expedition of the Western Australian Museum and partners. Tridacna maxima had a limited distribution and was only genotyped from offshore oceanic reefs in the Rowley Shoals and Cocos Keeling Islands. In contrast, T. noae was well established beyond Ningaloo Reef, and was abundant at inshore sites throughout the Pilbara and Kimberley, and even offshore to Ashmore Reef. Phylogeographically, T. maxima did not group with conspecifics from the Western Pacific Ocean, including the east coast of Australia, but instead clustered with individuals from Malaysia, China, Taiwan, and Indonesia; T. noae exhibited a similar pattern. The affinity of Western Australian individuals with representatives from the Indo-Malay region and not eastern Australia will be an important consideration for these commercially important species. Novel haplotypes in both tested species occur in Western Australia. Continued sampling of eastern and central Indian Ocean giant clams, especially to continue to document the range of T. noae, is encouraged to understand connectivity in this basin. Together, these findings contribute to an improved baseline for conservation initiatives of these iconic coral reef animals in Western Australia. Full article

(This article belongs to the Section Marine Diversity)

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19 pages, 2882 KiB

Open AccessArticle

Population Genomics and Application for Growth Improvement of Domesticated Asian Seabass Lates calcarifer from Thailand

by Bavornlak Khamnamtong, Atra Chaimongkol, Sirikan Prasertlux, Sirithorn Janpoom, Jutaporn Chaimongkol, Sureerat Tang, Wanwipa Ittarat, Putth Songsangjinda, Takashi Sakamoto, Panya Sae-Lim and Sirawut Klinbunga

Diversity 2025, 17(6), 383; https://doi.org/10.3390/d17060383 - 29 May 2025

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Abstract

A breeding program of Asian seabass (Lates calcarifer, also called barramundi) was established for sustainable aquaculture in Thailand. Estimated breeding values (EBVs) for growth of the base population (G0, 51 families, N = 1655) were evaluated. Fish exhibited either high (HEBV, [...] Read more.

A breeding program of Asian seabass (Lates calcarifer, also called barramundi) was established for sustainable aquaculture in Thailand. Estimated breeding values (EBVs) for growth of the base population (G0, 51 families, N = 1655) were evaluated. Fish exhibited either high (HEBV, averaged body weight = 1036.80 ± 250.80 g, N = 133) or low (LEBV, averaged body weight = 294.50 ± 167.20 g, N = 147) growth EBVs, and their parental fish (N = 26) were analyzed by Specific Locus Amplified Fragment Sequencing (SLAF-Seq). An average of 159,769 SLAF tags/sample was generated, covering 13.79-fold of the genome size, and 225,498 SNPs were applied for population genomics. Observed (H_o) and expected (H_e) heterozygosity values were 0.224 and 0.308, 0.178 and 0.246, and 0.184 and 0.305, respectively. Polymorphic information content (PIC) ranged from 0.205–0.251. A selective sweep was performed based on Fst, and nucleotide polymorphism (π) revealed significant differences between allelic contents of growth- and immune-related genes in HEBV and LEBV populations. Kinship analysis revealed that 84.38% of examined fish showed r values < 0.2, and population admixture analysis revealed three subpopulations in HEBV and four subpopulations in LEBV groups. Fish that possessed a single cluster were found in each subgroup of both populations, along with those exhibiting mixed ancestral clusters. This information is critically important for further applications in our ongoing seabass improvement breeding program. Full article

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