Wyniki wyszukiwania - Biblioteka Nauki

1

Bat activity at a small wind turbine in the Baltic Sea

100%

Rydell J. , Wickman A.

Acta Chiropterologica

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2015

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tom 17

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nr 2

EN

Activity of bats at an old wind park four km off the island of Gotland in the Baltic Sea was monitored during 50 nights from August to October 2013, using an automatic bat detector (Pettersson D500-X) mounted on one of the turbines. Single individuals or pairs of common noctules Nyctalus noctula were recorded on five occasions only (26 and 27 August), all in calm weather and when little or no rotor movement occurred. Since such conditions were unusual (five of 50 nights of observation) the visits by the bats were unlikely to be chance events (migrating bats passing the turbine), but more likely involved bats attracted to the turbines. However, no feeding buzzes were recorded and the bats never stayed near the turbine more than one minute. The turbines studied are lit by 250 W white lights and this could have been the reason why bats visited the turbines, because such lights potentially attract insects. The bats could not have been attracted to the turbines by any factor related of the movement of the rotor or the generator, such as Doppler-effects, noise, heat or electric fields.

2

Coastal cliffs on islands as foraging habitat for bats

80%

Ancillotto L. , Rydell J. , Nardone V. , Russo D.

Acta Chiropterologica

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2014

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tom 16

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nr 1

EN

Small islands usually show simplified ecosystems with limited availability of suitable foraging habitats for bats, thus habitat selection on islands may differ compared to the mainland. Habitats that are marginal on the mainland may be important on islands. The island of Capri consists, to a large extent, of steep limestone cliffs and Mediterranean shrubland, with virtually no forests or other habitats preferred by bats on the mainland. In this study we tested the hypothesis that in resource-limited systems, such as islands, habitats generally deemed of minor value for bat foraging, such as cliffs, may become important. We conducted an acoustic survey of bats in Capri (SW Italy), comparing their use of Mediterranean shrubland and limestone cliffs. We found that cliffs provided the preferred foraging habitat in four of the five species tested. Noticeably, even the barbastelle bat Barbastella barbastellus, normally considered a forest specialist, selected coastal cliffs as foraging habitat. Our observations indicate that the paucity of foraging habitats on islands may strongly alter the habitat use by bats. This has important implications for conservation of bats in insular environments.

3

Fly-and-forage strategy in the Bat Pipistrellus nathusii During Autumn Migration

80%

Suba J. , Petersons G. , Rydell J.

Acta Chiropterologica

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2012

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tom 14

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nr 2

EN

Populations of Pipistrellus nathusii (Nathusius's bat), an insectivorous aerial-hawking species that breeds in north-eastern Europe, perform long-distance migrations between breeding sites and hibernation areas in central and southern Europe. The feeding strategy of migrating P. nathusii was investigated in Latvia on the east coast of the Baltic Sea, exploring evidence for and against two non-mutually exclusive predictions that i) the bats feed shortly after dusk at highest aerial insect activity and continue to migrate thereafter or ii) apply a ‘fly-and-forage’ strategy and frequently interrupt their migration flight to feed. Echolocation calls and feeding buzzes of P. nathusii were recorded throughout the night from August until September on a known migration flyway over coastal dunes and at potential foraging sites in adjacent woodlands, over meadows and wetlands. The results indicate that P. nathusii applies a fly-and-forage strategy along the Baltic coast. However, a threshold in aerial insect availability may exist, below which no foraging occurs and migration continues.

4

Long-term increase in hibernating bats in Swedish mines - effect of global warming?

80%

Rydell J. , Eklof J. , Fransson H. , Lind S.

Acta Chiropterologica

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2018

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tom 20

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nr 2

EN

We present the result of bat winter censuses in three old mines in southern Sweden from 1980 until present (2017). The Taberg and Kleva mines, each with about 1.5 km of accessible passages, have winter populations of 517 and 132 bats, respectively (maximum counts) belonging to six species, the highest numbers known in underground sites in Sweden. Ädelfors is less extensive and has fewer individuals (maximum 22). The two former sites were protected and gated in the 1980′s while the third site still has no formal protection and is subject to disturbance. Generally Daubenton's bat Myotis daubentonii and the brown long-eared bat Plecotus auritus are common species and the numbers are stable. The whiskered and Brandt's bats M. mystacinus/brandtii and Natterer's bat M. nattereri have increased significantly, while the northern bat Eptesicus nilssonii, which is relatively rare in mines generally, has shown a slight but significant decline. At the species level the population trends conform well to those of the respective species in continental Europe and the British Isles. This suggests that there is a common factor behind the population changes across Europe. Although our data are very limited, the results question some previous explanations for the observed trends, but are in line with theoretical predictions based on global warming scenarios.

5

Bat mortality at wind turbines in Northwestern Europe

61%

Rydell J. , Bach L. , Dubourg-Savage M. J. , Green M. , Rodrigues L. , Hedenstrom A.

Acta Chiropterologica

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2010

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tom 12

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nr 2

EN

We reviewed published and unpublished written reports on bat mortality at wind farms in northwestern Europe. The estimated number of bats killed per turbine annually was relatively low (0–3) on flat, open farmland away from the coast, higher (2–5) in more complex agricultural landscapes, and highest (5–20) at the coast and on forested hills and ridges. The species killed almost exclusively (98%) belonged to a group (Nyctalus, Pipistrellus, Vespertilio and Eptesicus spp.) adapted for open-air foraging. The bats were killed by the moving rotor blades as they hunted insects attracted to the turbines. This occurred independently of sex and age. Peak mortality varied considerably in frequency and timing among years, but the events usually (90%) occurred on nights with low wind speeds in late July to early October and to a lesser extent (10%) also in April-June. The mortality increased with turbine tower height and rotor diameter but was independent of the distance from the ground to the lowest rotor point. It was also independent of the size of the wind park (1–18 turbines). Bat species other than the open-air suite referred to above are usually not at risk at wind turbines, because they fly below the rotors, but are still killed occasionally (2%).

6

Opportunistic use of banana flower bracts by Glossophaga soricina

61%

Murphy M. , Clare E. L. , Rydell J. , Yovel Y. , Bar-On Y. , Oelbaum P. , Fenton M. B.

Acta Chiropterologica

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2016

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tom 18

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nr 1

EN

The evolution of cue reception and cue production is well documented. The ability of species to use cues they did not evolve with is important in understanding flexibility in behaviour. We observed Neotropical nectar-feeding bats (Glossophaga soricina) feeding at Old World banana flowers (Musa acuminata) in a Belize garden. The flowers produce a rich source of nectar that is exposed as a bract lifts before dusk. We tested the hypothesis that the bracts serve as beacons to foraging bats and discuss this approach and the use of acoustic information by bats feeding at flowers. We ensonified a bract with cues like those of echolocating G. soricina, which revealed the production of strong echoes from the bract. Additionally, the removal of bracts from the flowers influenced the bats' flower-visiting behaviour. We suggest that the bats use the echoes from the bract opportunistically as a cue to find the nectar source. Our findings provide an example of an interaction between a plant and flower visitor not reflecting a shared evolutionary past.

7

Phenology of migratory bat activity across the Baltic Sea and south-eastern North Sea

41%

Rydell J. , Bach P. , Diaz L. G. , Furmankiewicz J. , Hagner-Wahlsten N. , Kyheroinen E.-M. , Lilley T. , Masing M. , Meyer M. M. , Petersons G. , Suba J. , Vasko V. , Vintulis V. , Hedenstrom A.

Acta Chiropterologica

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2014

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tom 16

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nr 1

EN

We compiled the available information on the occurrence and timing of migratory bat activity across the Baltic Sea and south-eastern North Sea coasts and islands, based on ultrasonic monitoring projects at 19 localities in 2007–2009. The data refer to three species; Nathusius' pipistrelle Pipistrellus nathusii, soprano pipistrelle P. pygmaeus and common noctule Nyctalus noctula. Pipistrellus nathusii occurred at all sites (north to 61°N in Finland), while the other species were scarcer, particularly at the northernmost sites. The status of the recorded individuals is unknown. However, the activity most likely was of migrating individuals or individuals on migration stopover, because very few observations were made during the maternity period. Spring activity occurred predominantly in May, with the median observation date of P. nathusii 20 days earlier in the south (Germany) than in the north (Finland). Autumn migration was observed throughout August and September and activity that may or may not indicate migration was also observed in October and November. The median date of such activity in autumn usually occurred in September and without any significant difference in timing in relation to latitude. Migratory bats in the Baltic area apparently move on a broad front in most cases. The estimated speed of migration for P. nathusii in spring was 55 km/day. The entire coastline and islands around the Baltic Sea are of potential importance for migrating bats in spring (April-May) and autumn (August-September) and should achieve relevant protection according to EU legislation and its implementations.