/library/oar/handle/123456789/7984 2025-11-06T13:19:15Z /library/oar/handle/123456789/122375 Title: Isolation and characterization of mycorrhizae and mycorrhiza-like associations from soil of the Maltese Islands Abstract: Studies of soil fungal diversity in the Maltese Islands are still considered sporadic and limited. The aim of the present work was to carry out studies to investigate the presence of Trichoderma spp. within the ascomycota, ectomycorrhizae and arbuscular mycorrhizae in the Maltese Islands and eventually to effect their isolation and preservation on different substrates. Soils samples were initially cultured Potato Dextrose Agar medium at a temperature of 27°C in the light. After microscopic inspection, fast-growing colonies with phialides and conidiophores which are typical of Trichoderma growth, were selected for monoconidial isolation. In total, nine dinstinct isolates were made using a monoconidial isolation technique, and their growth patterns and rate of growth were measured and photographically recorded. To help in identification of isolates, micromorphological studies were carried out using different staining techniques for light microscopy. In addition, DNA barcoding was carried out. Seven strain of the Trichoderma harzianum complex were identified for different soils and media in the Maltese Islands as well as another two new records of Trichoderma species namely T. virens and T. citrinoviride. These Trichoderma isolates were preserved in sterile 99% glycerol, sterile distilled water, Synthetic Nutrient Agar, Potato Dextrose Agar, and spent coffee grounds. Spore and mycelium viability were confirmed after one year for all of them. The search for ectomychorrizae was conducted during the rainy season between 2015 and 2019. Ten records were confirmed, and of which two are new records for the Maltese Islands namely Russula ochrosporea and Hebeloma quercetorum were discovered. For Hebeloma quercetorum it was also possible to measure the rate of growth of the basidiocarp. For the arbuscular mycorrhizae study, plant-traps were set up and their presence was confirmed as vesicles within the roots of Daucus carota, Carya illinoinensis and Quercus ilex. As far as is known, this was the first record of arbuscular mycorrhizae detected in Maltese soils. Description: M.SC.BIOLOGY 2020-01-01T00:00:00Z /library/oar/handle/123456789/121410 Title: Effects of artificial illumination on the presence of bat species Abstract: Artificial light at night, or ALAN, is an issue that is gaining prominence around the world due to the continual urbanisation that is encroaching on natural areas. ALAN induces physiological impacts in insectivorous bats, as well as behavioural changes in the insects they consume, resulting in the bats exhibiting species and population- specific behavioural responses. The aim of this study was therefore to investigate the effects of artificial illumination on the presence of local bat species. Acoustic monitoring was carried out for 24 nights in two sites located in Naxxar, Malta, one classified as the ‘dark’ site, which was not directly illuminated by ALAN, and one classified as the ‘illuminated’ site, which was directly illuminated by ALAN. Insect sampling using UV light traps was carried out in both sites for 15 nights. Kaleidoscope software was used to identify the bat signal recordings to species and genus level, and to quantify bat activity in the two sites. Analyses were carried out to statistically compare the differences in bat activity and insect presence between the two sites. Six bat species were identified from the ultrasonic recordings. The t-test analysis indicated statistically significant difference in bat activity for the bat species Hypsugo savii, showing higher activity in the illuminated site. Although no statistically significant differences were observed for the other bat taxa, the average nightly activity of Pipistrellus pipistrellus, traditionally a light-tolerant species, indicated higher activity in the dark site, while that of Pipistrellus kuhlii, also considered light-tolerant, indicated higher activity in the illuminated site, possibly indicating out-competition by the latter. The average nightly activity of Plecotus gasleiri and Myotis punicus, both considered light-averse, indicated higher activity in the illuminated site. The light-averse species, Rhinolophus hipposideros, showed higher nightly average activity in the dark site. The fact that most of the species exhibited higher activity in the illuminated site, even those considered to be light-averse, may indicate a local behavioural adaptation whereby local bat populations are being forced to withstand the ALAN, and the physiological effects that come with it, during foraging and commuting due to increased urbanisation and habitat fragmentation. These impacts on bat activity indicate a need for stronger ALAN guidelines and legislation locally to tackle the effects of urbanisation and protect darkened areas for local bat populations to thrive. Description: B.Sc. (Hons)(Melit.) 2023-01-01T00:00:00Z /library/oar/handle/123456789/121389 Title: DNA barcoding and phylogenetics of marine molluscs in Maltese waters Abstract: The Phylum Mollusca is the second largest phylum with regards to extant species in the kingdom Animalia. Molluscs boast a very high species diversity, being divided into several major taxonomic groups, the most important of which for this study being the classes Gastropoda, Bivalvia, Polyplacophora and Cephalopoda. Marine molluscs are known to have a high level of importance due to their applications in ecosystems, commercial products, ecological/eco-toxicological research, and biomedical research, despite this they are still faced with threats, including habitat loss and degradation, over-exploitation, pollution, climate change and disease. To formulate effective conservation strategies to counteract these threats, species must first be properly identified to be monitored within specific localities. Although morphological identification is an important tool for this, phenotypic plasticity and subjectivity tend to lead to misidentifications, hence the need for a complementary approach, DNA barcoding. DNA barcoding using the cytochrome c oxidase subunit one gene was used to identify marine mollusc species in Maltese waters, successfully identifying 76 out of 119 specimens. In addition to this, phylogenetic analysis was used to check the evolutionary relationships between analysed specimens. This study shows that DNA barcoding is an effective method of identifying Maltese marine molluscs of the relevant four classes when paired with morphological identification, as it bypasses issues such as phenotypic plasticity, damaged specimens, cryptic species complexes and different life stages and could identify species relevant to conservation including invasive and vulnerable species. Future studies should utilise other primers and DNA markers and to test their effectiveness on marine molluscs. Sampling should also be done in more localities to assess Maltese marine mollusc biodiversity more effectively. Description: B.Sc. (Hons)(Melit.) 2023-01-01T00:00:00Z /library/oar/handle/123456789/121388 Title: Molecular genetics of aliens in Maltese waters Abstract: The Mediterranean Sea is a hotspot of marine biodiversity, characterised by endemism and host to emblematic species of concern for conservation. Yet its habitats and ecosystems face many threats of anthropogenic origin, among the most prominent of which are biological invasions. Their initial introduction facilitated primarily by the opening of the Suez Canal, fouling and the transport of ballast water along shipping routes, invasive alien species have on several occasions caused rapid population declines, range shifts, and even local extirpations. Such ecological declines have in turn incurred the states that border the Mediterranean Sea costs amounting to billions of euros, ultimately prompting the enactment of Union-level regulations that demand the early detection and rapid eradication of the alien species invading the basin. The capacity to identify alien species is fundamental to their effective management. Their monitoring necessitates the use of diagnostic tools that are accurate, readily deployable, cost-effective, and applicable across a range of taxa. Traditional approaches to identification that are reliant on morphological characteristics fall short of these criteria, prompting in turn investigations into novel molecular approaches. This provided, the scope of the present project was to investigate the applicability of the cytochrome c oxidase subunit I (COI) gene in identifying newcomers to Maltese coastal waters and to contrast the genetic data it yields with morphological lines of evidence as part of an integrative approach towards correct species identification. Specimens from diverse metazoan taxa suspected to be of alien origin were collected and their morphologies documented. Tissue samples were excised from each specimen and treated with proteinase K for DNA extraction. Segments of the COI gene were then amplified, sequenced, and compared with the genetic data available in the international repositories of GenBank and BOLD. Genetic species identifications were thus derived and complemented with morphological species identifications. Phylogenetic trees of maximum likelihood were also constructed. The molecular approach described above allowed for the species identification of a total of 57 specimens. This enabled in turn the reliable distinction of alien specimens from native specimens. Morphological identifications corroborating the genetic identifications were possible for 50 specimens. Moreover, the single specimen of Siganus rivulatus presented here constitutes the first record of the species for the Maltese Islands. 12 of the haplotypes sequenced in the process of completing this project constitute newly discovered genetic variants for 7 species. The results of the present project emphasise the need for a molecular approach to species identification, especially in scenarios where: specimen morphologies are largely lost or deteriorated; morphological keys are not sufficiently informative; and specimen morphologies are cryptic or at least highly similar. Ultimately, the integration of genetic and morphological lines of evidence throughout this project produced a more robust approach that consistently guided the research undertaken towards accurate specimen identification. This approach’s application in regimes tasked with detecting, managing, and preventing marine invasions is thus recommended. Description: B.Sc. (Hons)(Melit.) 2023-01-01T00:00:00Z