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Bacteria that are capable of organizing themselves as biofilms are an important public health issue. Knowledge discovery focusing on the ability to swarm and conquer the surroundings to form persistent colonies is therefore very important for microbiological research communities that focus on a clinical perspective. Here, we demonstrate how a machine learning workflow can be used to create useful models that are capable of discriminating distinct associated growth behaviors along distinct phenotypes. Based on basic gray-scale images, we provide a processing pipeline for binary image generation, making the workflow accessible for imaging data from a wide range of devices and conditions. The workflow includes a locally estimated regression model that easily applies to growth-related data and a shape analysis using identified principal components. Finally, we apply a density-based clustering application with noise (DBSCAN) to extract and analyze characteristic, general features explained by colony shapes and areas to discriminate distinct Bacillus subtilis phenotypes. Our results suggest that the differences regarding their ability to swarm and subsequently conquer the medium that surrounds them result in characteristic features. The differences along the time scales of the distinct latency for the colony formation give insights into the ability to invade the surroundings and therefore could serve as a useful monitoring tool.
The ash whitefly, Siphoninus phillyreae (Haliday) (Hemiptera: Aleyrodidae), was first found in southern areas of South Korea during September 2019. During the survey of 2021, no additional specimens of the ash whitefly were found other than the previously reported regions. Attempts to trace a possible pathway for exotic ash whitefly suggested that this species probably followed pathways of illegal importation of infested plants from China or Japan and was unintentionally introduced into South Korea based on a survey-based study. This whitefly has not been intercepted at ports of entry to South Korea on imported plant material between 1999 and 2019 according to the PIS database (2021). Because of its wide host range and an ability to buildup massive populations, it will require continuous monitoring to prevent the spread to other areas of the country and to minimize potential losses of agriculturally and horticulturally important plants.
Container-breeding Aedes spp. (Diptera: Culicidae) mosquitoes can be surveilled at low cost using ovitraps. Hence, this method is a preferred monitoring approach of dengue vectors in low-resource settings. The ovitraps consist of a cup filled with water and an oviposition substrate for female mosquitoes. The attractiveness of the substrates for female mosquitoes can greatly differ due to differences in texture, color, and smell of the materials used. We compare four oviposition substrates, which are all low priced, easy to transport, and easy to purchase, to maximize the success of Aedes egg sampling. Sampled egg material is often reared to adulthood for further taxonomic identification and transported to (international) laboratories for specialized vector research. Here we introduce a transport technique for sampled eggs. In addition, we explored the impact of international transport by means of a bilateral hatching experiment in Nepal, the country of origin, and in Germany, in a laboratory specialized in ecophysiological research. The best low-cost oviposition substrate for the dengue vectors Aedes albopictus (Skuse) and Aedes aegypti (L.) was found to be a white cotton sheet. The introduced transport technique of sampled eggs is easy to build from laboratory and household materials and ensures good transport conditions (i.e., temperature and relative humidity). Even under good temperature (17.4–31.0 °C) and humidity conditions (58.9–94.2%), hatching success of eggs was found to be reduced after international transport to Germany when compared to the hatching success of eggs in Nepal. We postulate that air pressure during international transport may have reduced the hatching success and strongly recommend pressure-regulated transport boxes for egg transport via airplane. As the proposed operation procedure is useful in assisting the monitoring of Ae. albopictus and Ae. aegypti in low-resource settings, Aedes researchers are encouraged to follow it for the sampling and transport of Aedes eggs.
High grazing pressure from over-abundant macropods (kangaroos) is perceived to have a detrimental impact on biodiversity. Studies have shown potential changes in state and retardation of degraded vegetation recovery while other investigations have shown correlations with increased floristic diversity. The responses of grasslands to high impact macropod grazing may not be universal. Endangered Themeda triandra-dominated grasslands, on coastal headlands of New South Wales (NSW) and the associated threatened flora are thought to be negatively affected by high macropod grazing. We assess these assumptions via a comparative investigation across 46 headlands (467 plots) on the North Coast of NSW, and a BACI (Before and After Control Incident) design grazing exclusion experiment at a particularly significant site. We compare floristic richness, species density, evenness, Shannon H, Whittaker Beta Diversity, occurrence of listed threatened flora, average sward height and macropod density. Look At Me Now Headland (LAMN), between Coffs Harbour and Woolgoolga has one of the highest recorded population densities of macropods. Here 16 permanent plots were placed with grazing exclusion cages erected around half. Sampling occurred annually (October-November) for four consecutive years (2015-2018). Under high macropod grazing pressure LAMN Headland was found to have the highest scores for total richness, species density, species diversity and moderate to high values for species evenness and beta diversity. Within grazing exclusion plots the sward height increased significantly and was associated with a significant decrease in species density, beta and alpha diversity. Our results indicate that macropod grazing, even at the highest intensities, may be beneficial to floristic species diversity within the endangered Themeda-grasslands of coastal headlands and seacliffs within the North Coast Bioregion of NSW; our broader comparative study would suggest that this may also be the case on other headlands.
Active species reintroduction is an important conservation tool when aiming for the restoration of biological communities and ecosystems. The effective monitoring of reintroduction success is a crucial factor in this process. Here, we used a combination of environmental DNA (eDNA) techniques and species distribution models (SDMs) to evaluate the success of recent reintroductions of the freshwater fish Alburnoides bipunctatus in central Germany. We built SDMs without and with eDNA presence data to locate further suitable reintroduction sites and potentially overlooked populations of the species. We successfully detected eDNA of A. bipunctatus at all reintroduction sites, as well as several adjacent sites mostly in downstream direction, which supports the success of reintroduction efforts. eDNA‐based species detection considerably improved SDMs for A. bipunctatus, which allowed to identify species presence in previously unknown localities. Our results confirm the usefulness of eDNA techniques as standard tool to monitor reintroduced fish populations. We propose that combining eDNA with SDMs is a highly effective approach for long‐term monitoring of reintroduction success in aquatic species.
Biosecurity measures are commonly used to prevent the introduction of non-native species to natural environments globally, yet the efficacy of practices is rarely tested under operational conditions. A voluntary biosecurity measure was trialled in the Norwegian high Arctic following concern that non-native species might be transferred to the region on the footwear of travellers. Passengers aboard an expedition cruise ship disinfected their footwear with the broad spectrum disinfectant Virkon S prior to and in-between landing at sites around the remote Svalbard archipelago. The authors evaluated the efficacy of simply stepping through a disinfectant foot bath, which is the most common practice of footwear disinfection aboard expedition cruise ships in the Arctic. This was compared to a more time consuming and little-used method involving drying disinfected footwear, as proposed by other studies. The two practices were evaluated by measuring microbial growth on paired footwear samples before and after disinfection under both conditions. Step-through disinfection did not substantially reduce microbial growth on the footwear. Allowing disinfected footwear to dry, however, reduced the microbial burden significantly to lower levels. Thus, the currently adopted procedures used aboard ships are ineffective at removing microbial burden and are only effective when footwear is given more time to dry than currently granted under operational conditions. These findings underscore results from empirical research performed elsewhere and suggest the need to better relay this information to practitioners. It is suggested that footwear should minimally be wiped dry after step-through disinfection as a reasonable compromise between biosecurity and practicability.
Departing from the principle of absolute priority, CoCo bonds are particularly exposed to bank losses despite not having ownership rights. This paper shows the link between adverse CoCo design and their yields, confirming the existence of market monitoring in designated bail-in debt. Specifically, focusing on the write-down feature as loss absorption mechanism in CoCo debt, I do find a yield premium on this feature relative to equity-conversion CoCo bonds as predicted by theoretical models. Moreover, and consistent with theories on moral hazard, I find this premium to be largest when existing incentives for opportunistic behavior are largest, while this premium is non-existent if moral hazard is perceived to be small. The findings show that write-down CoCo bonds introduce a moral hazard problem in the banks. At the same time, they support the idea of CoCo investors acting as monitors, which is a prerequisite for a meaningful role of CoCo debt in banks' regulatory capital mix.
The management of invasive alien species (IAS) in protected areas has become increasingly important in recent years. In this study, we analyse IAS management in the bilateral National Park Thayatal-Podyjí at the Austrian-Czech border. Based on two surveys from the years 2001 and 2010 and on annual management data from 2001-2010 we analyse changes in distribution and the efficiency of IAS management of three invasive alien plants (Fallopia × bohemica, Impatiens glandulifera, Robinia pseudoacacia). In 2010, the three study species had invaded 161 ha (2%) of the study area. Despite a decade of management, F. × bohemica has become widespread, whereas I. glandulifera distribution has decreased strongly. The most widespread species, R. pseudoacacia, has declined substantially in cover, but the area invaded has increased. From 2001 to 2010, annual management effort declined by about half. Management effort per hectare and decade was highest for F. × bohemica (2,657 hours), followed by R. pseudoacacia (1,473 hours) and I. glandulifera (270 hours). Management effort for achieving the same amount of reduction in population size and cover was highest for R. pseudoacacia, followed by F. × bohemica and I. glandulifera. We conclude that substantial effort and resources are necessary to successfully manage the study species and have to be provided over prolonged time periods, and thus continued management of these species is recommended. We highly recommend a systematic approach for monitoring the efficiency of IAS management projects in protected areas.
Der Harz ist neben seinen Wäldern auch durch seine bunten Bergwiesen bekannt. Letztere sind schon seit längerer Zeit durch Nutzungsaufgabe oder intensivere Nutzung bedroht und gehören zu den besonders schutzbedürftigen Pflanzengesellschaften. Seit den 1980er Jahren werden zunehmend staatlich geförderte Pflegemaßnahmen zu ihrer Regeneration und Erhaltung durchgeführt. Im NSG „Bergwiesen bei St. Andreasberg“ sind seit 1987 wieder große Flächen durch einen ortsansässigen Landwirt gemäht worden. Zur Erfolgskontrolle und Erprobung anderer Pflegemaßnahmen wurden 1988 für ein Biomonitoring mehrere Dauerflächen eingerichtet, mit 10 x 10 m-Parzellen für jährliche Mahd und Brache, teilweise auch für Mahd alle zwei oder drei Jahre sowie Mulchen. Die Parzellen wurden bis 2002 auf 2x2 m-Kleinflächen erfasst. 2003 wurden die ganzen Parzellen aufgenommen, zusätzlich die Vertikalstruktur (Höhe der Schichten) und die oberirdische Biomasse gemessen.
Beschrieben werden hier vier Dauerflächen, zwei in Goldhaferwiesen (Geranio-Trisetetum potentilletosum erectae), je eine in einem Borstgrasrasen (Polygalo-Nardetum) und in einem Rubus idaeus-Brachestadium. Die Ergebnisse zeigen, dass sich durch jährliche Mahd mit Abfuhr des Mähgutes überall wieder eine artenreiche, bunt blühende Magerwiese mit offener Struktur und kleinwüchsigen Pflanzen eingestellt hat. Mahd alle zwei oder drei Jahre fördert etwas wuchskräftigere Arten. Mulchen erscheint wegen stärkerer Streubildung weniger geeignet. In den Brachen haben sich Hochstaudenfluren oder andere Dominanzstrukturen entwickelt. Eine Schlüsselart für die Regeneration ist Meum athamanticum, dessen Wuchskraft am besten durch jährliche Mahd eingedämmt wird. In der Diskussion wird deshalb als beste Erhaltungsmaßnahme eine jährliche Mahd ab Ende Juni empfohlen, möglichst im Mosaik mit seltener bis gar nicht gemähten Flächen. Auch eine extensive Beweidung wird diskutiert.
Die flächenmäßige Entwicklung von Bärlauch-Beständen eines Schonwaldes im Vorland der Schwäbischen Alb wird über einen Zeitraum von drei Jahrzehnten verglichen. Im Zeitraum von Ende der 1970er Jahre bis 2007 haben sie sich um mehr als das 2,5-fache ihrer Wuchsfläche ausgedehnt (264 %). Verschiedene Ursachen für die Expansion werden diskutiert. In einer Änderung der Art der Waldnutzung und einer Ozeanisierung des Klimas mit der Folge milderer Winter werden die Hauptgründe gesehen.