The biology and systematics of South African pipefishes of the genus Syngnathus

Syngnathus the most speciose genus in the family Syngnathidae is widely in the Atlantic and Eastern Pacific oceans. However, it is poorly represented in the Indian Ocean with the only two species, Syngnathus temminckii and S. watermeyeri occurring in Southern African estuaries and coastal areas. Syngnathus temminckii the most common South African pipefish has been synonymised with S. acus, as the morphological and genetic divergence between these two populations has not been documented. There is also uncertainty in the taxonomic status of S. watermeyeri, an endemic estuarine pipefish that is restricted to two Eastern Cape estuaries. The purpose of this study was therefore to compare biological, morphological and genetic variation of South African Syngnathus species among different populations/locations, and with European populations of S. acus. Sixteen meristic and ten morphometric characteristics were quantified from specimens obtained from field as well as various international natural history museum collections. Univariate (ANOVA) and multivariate (principal component analysis and discriminant analyses) analyses were used to assess morphological differences among the species. Morphometric variables were adjusted as ratios of the standard length and using an allometric procedure. ANCOVA analysis indicated significant differences between S. acus and S. temminckii for the relationships of the standard length (SL) and all morphological characters. There was no significant correlation between SL and snout length, snout depth, inter-orbital width and trunk depth for S. watermeyeri. The analyses provided evidence for distinct populations of S. acus, S. temminckii and S. watermeyeri although morphological character differentiation was greater between S. watermeyeri and the other two larger species. Although, significant differences were observed for meristic characters, pairwise comparisons did not reflect a clear pattern of variability. Most of the measured morphological characters contributed more than 70% to the morphological variation between the populations. Plot of the canonical scores for the variables resulted in the specimens clustering according to species groups and locations of S. temminckii. Sequences of 750 base pairs of the mitochondrial cytochrome gene from 11 localities were compared with published sequences of other species of Syngnathus. Phylogenetic analysis was performed using parsimony, maximum likelihood (ML) and Bayesian inference (BI). The South African species were revealed to be sister-taxa with about 6 % divergence, while S. temminckii and S. acus had about 11% sequence divergence. 20 haplotypes among 46 total specimens from the three species. Gene flow was estimated at approximately 3 migrants per generation between the two South African populations and about 1 per generation between S. temminckii and S. acus. Such strong stock structuring among presumably recently established post-Pliocene (< 2 Million years ago) populations suggests that these species are reproductively isolated. Morphological and genetic variation observed in this study combined with current knowledge of life history attributes of the South African pipefishes indicate that conservative management decisions are necessary until the patterns and extent of differentiation among populations species-wide can be investigated further. It is thus being proposed that the name of the South African population of S. acus be changed to Syngnathus temminckii (Kaup, 1856)

The biology and systematics of South African pipefishes of the genus Syngnathus

Syngnathus the most speciose genus in the family Syngnathidae is widely in the Atlantic and Eastern Pacific oceans. However, it is poorly represented in the Indian Ocean with the only two species, Syngnathus temminckii and S. watermeyeri occurring in Southern African estuaries and coastal areas. Syngnathus temminckii the most common South African pipefish has been synonymised with S. acus, as the morphological and genetic divergence between these two populations has not been documented. There is also uncertainty in the taxonomic status of S. watermeyeri, an endemic estuarine pipefish that is restricted to two Eastern Cape estuaries. The purpose of this study was therefore to compare biological, morphological and genetic variation of South African Syngnathus species among different populations/locations, and with European populations of S. acus. Sixteen meristic and ten morphometric characteristics were quantified from specimens obtained from field as well as various international natural history museum collections. Univariate (ANOVA) and multivariate (principal component analysis and discriminant analyses) analyses were used to assess morphological differences among the species. Morphometric variables were adjusted as ratios of the standard length and using an allometric procedure. ANCOVA analysis indicated significant differences between S. acus and S. temminckii for the relationships of the standard length (SL) and all morphological characters. There was no significant correlation between SL and snout length, snout depth, inter-orbital width and trunk depth for S. watermeyeri. The analyses provided evidence for distinct populations of S. acus, S. temminckii and S. watermeyeri although morphological character differentiation was greater between S. watermeyeri and the other two larger species. Although, significant differences were observed for meristic characters, pairwise comparisons did not reflect a clear pattern of variability. Most of the measured morphological characters contributed more than 70% to the morphological variation between the populations. Plot of the canonical scores for the variables resulted in the specimens clustering according to species groups and locations of S. temminckii. Sequences of 750 base pairs of the mitochondrial cytochrome gene from 11 localities were compared with published sequences of other species of Syngnathus. Phylogenetic analysis was performed using parsimony, maximum likelihood (ML) and Bayesian inference (BI). The South African species were revealed to be sister-taxa with about 6 % divergence, while S. temminckii and S. acus had about 11% sequence divergence. 20 haplotypes among 46 total specimens from the three species. Gene flow was estimated at approximately 3 migrants per generation between the two South African populations and about 1 per generation between S. temminckii and S. acus. Such strong stock structuring among presumably recently established post-Pliocene (< 2 Million years ago) populations suggests that these species are reproductively isolated. Morphological and genetic variation observed in this study combined with current knowledge of life history attributes of the South African pipefishes indicate that conservative management decisions are necessary until the patterns and extent of differentiation among populations species-wide can be investigated further. It is thus being proposed that the name of the South African population of S. acus be changed to Syngnathus temminckii (Kaup, 1856)

Ammonia removal from water by ion exchange using South African and Zambian zeolite samples

One problem of intensive fish culture systems is the progressive build-up of toxic wastes such as ammonia. The possibility of improving aquaculture water quality using two kinds of zeolite is discussed. Zeolites are alumino-silicates whose framework allows them to exchange cations. Ion exchange has been demonstrated to be competitive with other methods of ammonia removal due to the high selectivity for ammonia exhibited by zeolite materials. In this study an unknown Zambian zeolite (identified as laumontite by X-ray diffraction techniques) and Pratley clinoptilolite (a South African zeolite) were tested under laboratory conditions and in a fresh water recirculating system. Ammonia cation exchange capacities (CEC) and suitable application rates for efficient water treatment were determined using the batch and column ion exchange procedures. Estimated ammonia uptake, the most important criterion used to assess performance of zeolite filters was strongly influenced by zeolite type, particle size, pre-treatment, regeneration and ion exchange method used. Statistical analysis showed significant differences in average ammonia CEC values between clinoptilolite (14.94 mg g⁻¹) and laumontite (2.77 mg g⁻¹), with the former displaying a higher Na⁺ ® NH₄⁺ exchange rate especially in the early reaction stages. This difference accords with the higher purity of clinoptilolite, 47% as opposed to 4.7% for laumontite, which makes it a better zeolite for ammonium removal. CEC increased linearly as particle size of the clinoptilolite was reduced resulting in a linear regression model (y = 18.29 – 3.704 x; r² = 74%). Pre-treatment of clinoptilolite using 1N NaCl significantly improved the ammonia CEC of clinoptilolite. Overall performance of both the batch and column methods achieved after regeneration (18.3 mg g⁻¹) was 25% higher than the estimated CEC values (13.0 mg g⁻¹) for the unregenerated samples of clinoptilolite. Comparison of CEC estimates using Pratley clinoptilolite, showed that average batch CEC estimates were significantly lower than the column method estimates. The average ammonia CEC values estimated in a fresh water recirculating system (5.80 mg g⁻¹ and 4.12 mg g⁻¹ for the 0.7-1.0 and 1.0-1.4 mm particle sizes, respectively) were significantly lower than the column and batch estimates for the same particle sizes (P < 0.05). Some nitrite (NO₂) and nitrate (NO3) build up was experienced probably due to the growth of autotrophs in the filters. Mass balance of nitrogen (N) for the three treatments of the fish trial (0.7-1.0 mm, 1.0-1.4 mm and the control treatment that had no zeolite in the filter) indicated that less that 10% of the N was retained for growth. It was found that 60% of the NH₄-N present associated with the soluble N was available for absorption by the zeolite filter or biological nitrification and that a total of approximately 22% of NH₄-N available was absorbed by clinoptilolite. The results indicate that the rate of nitrification can be deductively estimated by allowing a zeolite filter to become a biological filter. It is concluded that water treatment by ion exchange using natural zeolites, provides a reliable and efficient method for ammonia removal and appears to be a viable supplementary water treatment method for fresh water systems

Intra-African bird migration: Identifying contrasting patterns of connectivity in widely distributed species

Migration strategies within the tropics are poorly understood as are the drivers of movement and the degree of connectivity between sites in migrant birds that have their global range and life cycle exclusively on a single continent. Migratory connectivity between populations may be affected by past climatic fluctuations as well as contemporary threats that affect habitat connectivity resulting in genetic differentiation. Here, integrated molecular and morphological data was used to examine genetic diversity, elucidate patterns of differentiation and assess evolutionary history of western, eastern and southern African populations of African pygmy kingfisher (Ispidina picta), woodland kingfisher (Halcyon senegalensis) and Diederik cuckoo (Chrysococcyx caprius). Our results provided evidence of genetic lineages corresponding to subspecies designation for all three species. Lack of differentiation was observed within subspecies of African pygmy kingfisher and Diederik cuckoo, indicating that connectivity between populations has been maintained. However, genetic substructure was evident within woodland kingfisher with three distinct genetic clusters for birds from Ghana, Gabon and Uganda. Morphometric variation was identified between subspecies. We additionally detected a continental gradient in wing length from western to the eastern populations of woodland kingfisher as well as sexual dimorphism within I. p. natalensis. Here, we recommend that this or similar approaches be applied to other widespread African bird species that are often overlooked in a global conservation context. We further suggest that future conservation strategies should potentially focus on ensuring that connectivity between populations of migrant birds is maintained on the African continent

Intra-African bird migration: Identifying contrasting patterns of connectivity in widely distributed species

Migration strategies within the tropics are poorly understood as are the drivers of movement and the degree of connectivity between sites in migrant birds that have their global range and life cycle exclusively on a single continent. Migratory connectivity between populations may be affected by past climatic fluctuations as well as contemporary threats that affect habitat connectivity resulting in genetic differentiation. Here, integrated molecular and morphological data was used to examine genetic diversity, elucidate patterns of differentiation and assess evolutionary history of western, eastern and southern African populations of African pygmy kingfisher (Ispidina picta), woodland kingfisher (Halcyon senegalensis) and Diederik cuckoo (Chrysococcyx caprius). Our results provided evidence of genetic lineages corresponding to subspecies designation for all three species. Lack of differentiation was observed within subspecies of African pygmy kingfisher and Diederik cuckoo, indicating that connectivity between populations has been maintained. However, genetic substructure was evident within woodland kingfisher with three distinct genetic clusters for birds from Ghana, Gabon and Uganda. Morphometric variation was identified between subspecies. We additionally detected a continental gradient in wing length from western to the eastern populations of woodland kingfisher as well as sexual dimorphism within I. p. natalensis. Here, we recommend that this or similar approaches be applied to other widespread African bird species that are often overlooked in a global conservation context. We further suggest that future conservation strategies should potentially focus on ensuring that connectivity between populations of migrant birds is maintained on the African continent

Broad-scale genetic assessment of Southern Ground-Hornbills (Bucorvus leadbeateri) to inform population management.

The Southern Ground-hornbill (SGH) (Bucorvus leadbeateri) is considered an umbrella species for biodiversity conservation in savannah biomes since they require large territories and significant protection measures that help to conserve a wide range of biodiversity with similar savanna and grassland requirements. Declines of the species are attributed to low reproductive rates coupled with multiple anthropogenic threats, including secondary poisoning, and persecution. Little is known about connectivity and population structure of SGH populations in Africa, south of the equator. Knowledge of population differentiation is needed to ensure that targeted conservation management plans can be implemented to slow population declines and ensure survival of the species. To inform a long-term conservation strategy, we investigated the broad-scale population structure of Southern Ground-hornbill across their sub-equatorial range. Our study based on 16 microsatellite loci identified moderate variation (average of 5.889 alleles per locus and a mean observed heterozygosity of 0.546) similar to other long-lived avian species. In contrast, mitochondrial DNA sequences analysis identified low diversity (Hd = 0.3313, π = 0.0015). A Bayesian assignment approach, principal component analysis, analysis of molecular variance and phylogenetic analysis identified weak to moderate population structuring across long distances and mitochondrial data showed a shallow phylogeny. Restriction to long-distance dispersal was detected that could not be attributed to isolation by distance, suggesting that other factors, such as their dispersal biology, are shaping the observed genetic differentiation. Although our study does not support the designation of populations as independent conservation units, we advocate that population management should continue to follow the Precautionary Principle (mixing founders from the same range state, rather than allowing mixing of founders from the extremes of the range) until there is scientific certainty. Following further research, if no independent conservation units are detected, then the global captive population can contribute to reintroductions across the range. In the wild, populations at the edge of the species range may need additional management strategies and gene flow should be promoted between neighbouring populations

Broad-scale genetic assessment of southern ground-hornbills (Bucorvus leadbeateri) to inform population management

DATA AVAILABILITY : Bucorvus leadbeateri sequences are available on GenBank, accession numbers: OP046521-OP046574, and OP122231 - OP122407.The Southern Ground-hornbill (SGH) (Bucorvus leadbeateri) is considered an umbrella species for biodiversity conservation in savannah biomes since they require large territories and significant protection measures that help to conserve a wide range of biodiversity with similar savanna and grassland requirements. Declines of the species are attributed to low reproductive rates coupled with multiple anthropogenic threats, including secondary poisoning, and persecution. Little is known about connectivity and population structure of SGH populations in Africa, south of the equator. Knowledge of population differentiation is needed to ensure that targeted conservation management plans can be implemented to slow population declines and ensure survival of the species. To inform a long-term conservation strategy, we investigated the broad-scale population structure of Southern Ground-hornbill across their sub-equatorial range. Our study based on 16 microsatellite loci identified moderate variation (average of 5.889 alleles per locus and a mean observed heterozygosity of 0.546) similar to other long-lived avian species. In contrast, mitochondrial DNA sequences analysis identified low diversity (Hd = 0.3313, π = 0.0015). A Bayesian assignment approach, principal component analysis, analysis of molecular variance and phylogenetic analysis identified weak to moderate population structuring across long distances and mitochondrial data showed a shallow phylogeny. Restriction to long-distance dispersal was detected that could not be attributed to isolation by distance, suggesting that other factors, such as their dispersal biology, are shaping the observed genetic differentiation. Although our study does not support the designation of populations as independent conservation units, we advocate that population management should continue to follow the Precautionary Principle (mixing founders from the same range state, rather than allowing mixing of founders from the extremes of the range) until there is scientific certainty. Following further research, if no independent conservation units are detected, then the global captive population can contribute to reintroductions across the range. In the wild, populations at the edge of the species range may need additional management strategies and gene flow should be promoted between neighbouring populations.https://www.elsevier.com/locate/geccohj2024BiochemistryGeneticsMicrobiology and Plant PathologySDG-15:Life on lan

Trends in DNA barcoding and metabarcoding

This open-access special issue features 12 full articles representing emerging trends from the international DNAbarcoding community. Several articles highlight how DNA-based techniques are elucidating the species diversity,biogeography, and conservation status of Africas biodiversity. Another prominent theme is the movementtowards big biodiversity data using high-throughput, individual-based DNA barcoding methods, which preservevoucher specimens and abundance data, as well as bulk sample-based metabarcoding. Methodological developments are enhancing the detection of specific species and whole communities using environmental DNA(eDNA) barcoding and metabarcoding. Data are also expanding in terms of genetic coverage; in this issue, a newdatabase is established for a secondary fungalDNAbarcode marker, and multi-kingdom, multi-marker biodiversitysurveys are gaining traction. DNA barcode sequence data, often combined with complementary markers or taxonomic information, are increasingly contributing to large-scale phylogenetic projects, with implications for understanding evolutionary history, community structure, and conservation priorities.Fil: Adamowicz, Sarah J.. University of Guelph; CanadáFil: Boatwright, James S.. University of The Western Cape; SudáfricaFil: Chain, Frédéric. University of Massachusetts; Estados UnidosFil: Fisher, Brian L.. California Academy Of Sciences.; Estados UnidosFil: Hogg, Ian D.. Polar Knowledge Canada; CanadáFil: Leese, Florian. Universitat Essen; AlemaniaFil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Mwale, Monica. South African National Biodiversity Institute; SudáfricaFil: Naaum, Amanda M.. The Queens University of Belfast; IrlandaFil: Pochon, Xavier. University of Auckland; Nueva ZelandaFil: Schubert, Dirk W.. University of Guelph; CanadáFil: Wilson, John James. National Museums Liverpool; Reino UnidoFil: Wood, Susanna. Cawthron Institute; Nueva ZelandaFil: Xu, Jianping. Mcmaster University; CanadáFil: Xu, Sen. University of Texas at Arlington; Estados UnidosFil: Zhou, Xin. China Agricultural University; ChinaFil: Van Der Bank, Michelle. University of Johannesburg; Sudáfric

Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.

BACKGROUND: Child stunting reduces survival and impairs neurodevelopment. We tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF) on stunting and anaemia in in Zimbabwe. METHODS: We did a cluster-randomised, community-based, 2 × 2 factorial trial in two rural districts in Zimbabwe. Clusters were defined as the catchment area of between one and four village health workers employed by the Zimbabwe Ministry of Health and Child Care. Women were eligible for inclusion if they permanently lived in clusters and were confirmed pregnant. Clusters were randomly assigned (1:1:1:1) to standard of care (52 clusters), IYCF (20 g of a small-quantity lipid-based nutrient supplement per day from age 6 to 18 months plus complementary feeding counselling; 53 clusters), WASH (construction of a ventilated improved pit latrine, provision of two handwashing stations, liquid soap, chlorine, and play space plus hygiene counselling; 53 clusters), or IYCF plus WASH (53 clusters). A constrained randomisation technique was used to achieve balance across the groups for 14 variables related to geography, demography, water access, and community-level sanitation coverage. Masking of participants and fieldworkers was not possible. The primary outcomes were infant length-for-age Z score and haemoglobin concentrations at 18 months of age among children born to mothers who were HIV negative during pregnancy. These outcomes were analysed in the intention-to-treat population. We estimated the effects of the interventions by comparing the two IYCF groups with the two non-IYCF groups and the two WASH groups with the two non-WASH groups, except for outcomes that had an important statistical interaction between the interventions. This trial is registered with ClinicalTrials.gov, number NCT01824940. FINDINGS: Between Nov 22, 2012, and March 27, 2015, 5280 pregnant women were enrolled from 211 clusters. 3686 children born to HIV-negative mothers were assessed at age 18 months (884 in the standard of care group from 52 clusters, 893 in the IYCF group from 53 clusters, 918 in the WASH group from 53 clusters, and 991 in the IYCF plus WASH group from 51 clusters). In the IYCF intervention groups, the mean length-for-age Z score was 0·16 (95% CI 0·08-0·23) higher and the mean haemoglobin concentration was 2·03 g/L (1·28-2·79) higher than those in the non-IYCF intervention groups. The IYCF intervention reduced the number of stunted children from 620 (35%) of 1792 to 514 (27%) of 1879, and the number of children with anaemia from 245 (13·9%) of 1759 to 193 (10·5%) of 1845. The WASH intervention had no effect on either primary outcome. Neither intervention reduced the prevalence of diarrhoea at 12 or 18 months. No trial-related serious adverse events, and only three trial-related adverse events, were reported. INTERPRETATION: Household-level elementary WASH interventions implemented in rural areas in low-income countries are unlikely to reduce stunting or anaemia and might not reduce diarrhoea. Implementation of these WASH interventions in combination with IYCF interventions is unlikely to reduce stunting or anaemia more than implementation of IYCF alone. FUNDING: Bill & Melinda Gates Foundation, UK Department for International Development, Wellcome Trust, Swiss Development Cooperation, UNICEF, and US National Institutes of Health.The SHINE trial is funded by the Bill & Melinda Gates Foundation (OPP1021542 and OPP113707); UK Department for International Development; Wellcome Trust, UK (093768/Z/10/Z, 108065/Z/15/Z and 203905/Z/16/Z); Swiss Agency for Development and Cooperation; US National Institutes of Health (2R01HD060338-06); and UNICEF (PCA-2017-0002)