Browsing by Subject "lepakot"

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  • Lohi, Saska (Helsingin yliopisto, 2015)
    Bats can act as potential vectors for various zoonotic diseases and other pathogens. Therefore their interactions with people should be examined to mitigate potential risks. Bats are small flying mammals and hide in small crevices during daylight hours, making them difficult to observe. Consequently, they have a capacity to “hitchhike” on ships to be dispersed over large distances. This study focused on anthropogenic unintentional bat translocations, i.e. hitchhiking bats. The study area is the Great Lakes region in North America. Using a web-based questionnaire survey, I asked the public about the frequency of bat-human encounters on ships, their nature, and perceived risks and incidents. I found that bats are commonly seen by people working on ships at the Great Lakes. Bats do not cause trouble other than scaring people. Based on photographic evidence, at least one bat was seen on a ship outside of its native range. Therefore ships might act as vectors, helping bats to disperse to new areas. This might provide pathways for pathogens to spread along, from bats to bats or from bats to humans. The risks related to hitchhiking bats seem to be rather limited. Rabies risk is the most obvious, but no cases of people getting rabies infection from hitchhiking bats were acknowledged. The possibility of ships translocating bats infected with Pseudogymnoascus destructans remains unknown. This study demonstrates how by engaging the public it is possible to gather novel scientific knowledge, and deepen our understanding about the relationship between man and wildlife. There are numerous hidden ways of how people interact with animal species. This study illuminates one of these ways, but many more are yet to be studied.
  • Meller, Kalle Ilmari (Työ- ja elinkeinoministeriö, 2017)
    Työ- ja elinkeinoministeriön julkaisuja
    Wind power construction and plans for further construction projects have given rise to concern as to their impacts on birds and bats. Collisions of these species with wind turbines have been reported round the world. The review concerning the impacts of wind power projects on birds and bats in international peer-reviewed literature and reports on the impacts of wind power on these species, commissioned by the Ministry of Economic Affairs and Employment, was conducted on 1 March–30 May 2017. Based on the literature, birds and bats collide with wind turbines in in highly varying numbers, and the location of the turbines is important in terms of collision mortality. There is also considerable variation in the susceptibility of different species and sub-species to collide with wind turbines. In some places large numbers of birds and bats have collided with wind turbines built in unfortunate locations in terms of these species, but hardly any impacts on their population size have been observed. In the case of bats, in particular, lack of information on the ecology and population size of the species makes it difficult to detect changes in the population. For some bird species the disturbance and blocking effect of wind turbines may be more significant than collision mortality, but in most cases these impacts are restricted to the immediate vicinity of wind turbines and no impacts on the population size in larger regions have been observed. Based on research the building of more wind turbines in Finland is not likely to cause a significant threat to bird and bat populations, if the turbines are located in areas where their population densities are low and the risk of collisions can be minimised. However, there is not yet enough information on the impacts of wind turbines on birds and bats, and further studies and monitoring are needed to make sure that new wind power building projects will not affect the population sizes of species that are susceptible to collision in the future. In Finland, in particular, more research focused on bats and long-term monitoring of the impacts of wind turbines after they have been built are needed.
  • Suutari, Miina (Helsingin yliopisto, 2021)
    Even though bats have no specialized predators in the temperate zone, they are still predated on. In fact, 11% of their annual mortality is caused by avian predators, especially owls. Bats are particularly vulnerable at emergence from their roost because this behaviour is very predictable. Because a successful predation event is mortal, it would be expected that bats need antipredatory responses to avoid it. The time and focus for these responses need to be shared with foraging in a way that maximizes survival. I studied antipredatory responses of bats in two settings: 1. during roost emergence and 2. during foraging at tawny owl territories and at places where there have been no tawny owl sightings. I collected acoustic data from 24 roosts and 11 foraging grounds for 10-13 nights. The roost emergence data was collected with the help of citizen science. Two controlled predation threats, recorded tawny owl calls and nestling sounds, were used. Nestling sounds were only played during roost emergence. In both tests music and silence were used as controls. Owl calls, music or tawny owl territory have no effect on bat presence when they are foraging. However, bats alter their emergence time and leave over 20 minutes later when tawny owl calls are played outside the roost. There is no difference in exit time when music or nestling sounds are played. These results show that bats have antipredatory responses. They also suggest that bats may be able to recognize high-risk situations and allocate their behaviour accordingly or that they place higher importance on foraging than avoiding predation.
  • Nyholm, Erik S. (University of Helsinki, 1956)