Ecology and conservation of Garra ghorensis, an endangered freshwater fish in Jordan

The focal species of the research was the freshwater cyprinid fish Garra ghorensis. Endemic to the southern Dead Sea basin of the Middle East, it is ‘Red listed’ by the IUCN as ‘endangered’. It inhabits the small rivers of the basin (‘wadis’), existing within fish communities of very low species diversity. The aim of the research was to inform conservation strategies for the species through investigations into their phylogeny, current distribution, life history traits and feeding relationships. Analysis of the mitochondrial DNA of G. ghorensis with other fishes of the Garra genus tested two contrasting hypotheses on their biogeographic origin: whether they were descended from Garra tibancia in the Arabian Peninsula or from a common ancestor shared with Garra rufa, which would have indicated dispersal from the Mediterranean basin and Mesopotamia. The phylogenetic tree clearly indicated that G. ghorensis shared a common ancestor with G. rufa and thus was of Mediterranean origin. These phylogenetic analyses were then important for interpreting G. ghorensis biogeography in relation to their natural range and current distribution. Surveys completed in 2010 provided data on their spatial distribution; this distribution was at least partially explained by historical geological and water salinity changes of the proto-lakes of Lake Samra and Lisan. These surveys also revealed that during the 2000s, there had been little change in G. ghorensis distribution, with populations still present in wadis that were recorded in 2002. However, at the surveyed sites, some alterations to the physical habitats and hydrology of the wadis were apparent, such as construction of impoundments. To assess the life history traits and feeding relationships of G. ghorensis, three locally abundant populations were studied. These were an allopatric population, a population sympatric with the native cyprinid Capoeta damascina and a population sympatric with the invasive cichlid Oreochromis aureus. The allopatric and sympatric native populations were present in wadis with minimal habitat disturbance, whereas the sympatric invasive population was present in a wadi with substantial alteration, including some impoundments that deepened the main channel and reduced the flow. Analyses of ages, growth rates and reproductive traits revealed that life spans, growth rates and reproductive investment were greatest at this disturbed site, despite being relatively altered from the apparently preferred habitat of the species. These results suggested that providing the hydrological disturbance at sites where G. ghorensis is present still enables the completion of their life cycle then their populations can withstand some aspects of habitat disturbances from anthropogenic activities. The feeding relationships of G. ghorensis were then assessed in relation to the presence of C. damascina and O. aureus in two of the sites, and used a combination of stomach contents analyses and stable isotope analysis. Results from both methods revealed whilst there were some overlaps in the trophic niches of the fishes, diets were based mainly on detritus and algae. These items are rarely limiting in freshwaters and thus whilst resources were shared, it was unlikely to result in high levels of inter-specific competition. Thus, an important ecological feature of G. ghorensis populations is their plasticity in life history traits and their resource use that enables some adaptation to disturbed environments. This suggests that their conservation management does not necessarily have to return their habitats to pristine conditions, as their adaptive capacity should enable some adaptation to the new conditions and thus continued population sustainability. Consequently, providing that development schemes prevent the destruction of the key habitats required for the completion of the G. ghorensis lifecycle, then their populations could remain sustainable in the face of continued development in the region

Biological and trophic consequences of genetic introgression between endemic and invasive Barbus fishes.

Genetic introgression with native species is recognized as a detrimental impact resulting from biological invasions involving taxonomically similar invaders. Whilst the underlying genetic mechanisms are increasingly understood, the ecological consequences of introgression are relatively less studied, despite their utility for increasing knowledge on how invasion impacts can manifest. Here, the ecological consequences of genetic introgression from an invasive congener were tested using the endemic barbel populations of central Italy, where the invader was the European barbel Barbus barbus. Four populations of native Barbus species (B. plebejus and B. tyberinus) were studied: two purebred and two completely introgressed with alien B. barbus. Across the four populations, differences in their biological traits (growth, body condition and population demographic structure) and trophic ecology (gut content analysis and stable isotope analysis) were tested. While all populations had similar body condition and were dominated by fish up to 2 years of age, the introgressed fish had substantially greater lengths at the same age, with maximum lengths 410-460 mm in hybrids versus 340-360 mm in native purebred barbel. The population characterized by the highest number of introgressed B. barbus alleles (81 %) had the largest trophic niche and a substantially lower trophic position than the other populations through its exploitation of a wider range of resources (e.g. small fishes and plants). These results attest that the genetic introgression of an invasive congener with native species can result in substantial ecological consequences, including the potential for cascading effects. Supplementary Information: The online version contains supplementary material available at 10.1007/s10530-021-02577-6

Effective monitoring of freshwater fish

Freshwater ecosystems constitute only a small fraction of the planet’s water resources, yet support much of its diversity, with freshwater fish accounting for more species than birds, mammals, amphibians, or reptiles. Fresh waters are, however, particularly vulnerable to anthropogenic impacts, including habitat loss, climate and land use change, nutrient enrichment, and biological invasions. This environmental degradation, combined with unprecedented rates of biodiversity change, highlights the importance of robust and replicable programmes to monitor freshwater fish assemblages. Such monitoring programmes can have diverse aims, including confirming the presence of a single species (e.g. early detection of alien species), tracking changes in the abundance of threatened species, or documenting long-term temporal changes in entire communities. Irrespective of their motivation, monitoring programmes are only fit for purpose if they have clearly articulated aims and collect data that can meet those aims. This review, therefore, highlights the importance of identifying the key aims in monitoring programmes, and outlines the different methods of sampling freshwater fish that can be used to meet these aims. We emphasise that investigators must address issues around sampling design, statistical power, species’ detectability, taxonomy, and ethics in their monitoring programmes. Additionally, programmes must ensure that high-quality monitoring data are properly curated and deposited in repositories that will endure. Through fostering improved practice in freshwater fish monitoring, this review aims to help programmes improve understanding of the processes that shape the Earth's freshwater ecosystems, and help protect these systems in face of rapid environmental change

Aplikasi Pupuk Area Dan Pupuk Kandang Kambing Untuk Meningkatkan N Total Tanah Pada Inceptisol Kwala Bekala Dan Kaitannya Trhadap Pertumbuhan Jagung (Zea Mays L.)

This aims of research was study about the effect of application of urea fertilizer and goat manure toimprove N-total on Inceptisol Kwala Bekala and its relation to the growth of maize. The researchwas conducted in the screen house and Chemical and Soil Fertility Laboratory, Faculty ofAgriculture, University of North Sumatra .This study used randomized block designed whichconsists of 2 factors and 3 replications. The first factor urea which consists of 4 levels : 1. U0 (0kg/ha), 2. U1 (100 kg/ha), 3. U2 (200 kg/ha), 4. U3 (300 kg/ha) and the second factor of goatmanure: 1. K0 (0 tons/ha), 2. K1 (10 tons/ha), 3. K2 (20 tons/ha), 4. K3 (30 tons/ha).The resultsshowed urea fertilizer application increased significantly of plant height, the best treatment at 100kg/ha. Application of goat manure increased significantly soil C-organic, N-uptake, plant height,dry weight and dry root plant, the best treatment at 30 tons/ha. Interaction of urea fertilizerapplication and goat manure increased the dry weight of shoot and N-uptake. The best treatmentwas the application 100 kg/ha urea and goat manure 30 tons/ha

Adding nuclear rhodopsin data where mitochondrial COI indicates discrepancies – can this marker help to explain conflicts in cyprinids?

DNA barcoding is a fast and reliable tool for species identification, and has been successfully applied to a wide range of freshwater fishes. The limitations reported were mainly attributed to effects of geographic scale, taxon-sampling, incomplete lineage sorting, or mitochondrial introgression. However, the metrics for the success of assigning unknown samples to species or genera also depend on a suited taxonomic framework. A simultaneous use of the mitochondrial COI and the nuclear RHO gene turned out to be advantageous for the barcode efficiency in a few previous studies. Here, we examine 14 cyprinid fish genera, with a total of 74 species, where standard DNA barcoding failed to identify closely related species unambiguously. Eight of the genera (Acanthobrama, Alburnus, Chondrostoma, Gobio, Mirogrex, Phoxinus, Scardinius, and Squalius) contain species that exhibit very low interspecific divergence, or haplotype sharing (12 species pairs) with presumed introgression based on mtCOI data. We aimed to test the utility of the nuclear rhodopsin marker to uncover reasons for the high similarity and haplotype sharing in these different groups. The included labeonine species belonging to Crossocheilus, Hemigrammocapoeta, Tylognathus and Typhlogarra were found to be nested within the genus Garra based on mtCOI. This specific taxonomic uncertainty was also addressed by the use of the additional nuclear marker. As a measure of the delineation success we computed barcode gaps, which were present in 75% of the species based on mtCOI, but in only 39% based on nuclear rhodopsin sequences. Most cases where standard barcodes failed to offer unambiguous species identifications could not be resolved by adding the nuclear marker. However, in the labeonine cyprinids included, nuclear rhodopsin data generally supported the lineages as defined by the mitochondrial marker. This suggests that mitochondrial patterns were not mislead by introgression, but are caused by an inadequate taxonomy. Our findings support the transfer of the studied species of Crossocheilus, Hemigrammocapoeta, Tylognathus and Typhlogarra to Garra