Jens Rydell

Jens Rydell
Lund University | LU · Department of Biology

PhD Lund University 1990

About

110
Publications
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Publications

Publications (110)
Article
Bat ultrasound analysis has been around for several decades and it is one of the most important tools in studies of bat ecology. Discrimination between species is based on intra-specific features of echolocation calls. Identification of species and genera in audio files can be attempted either manually or through software which performs a fully aut...
Article
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We review how different bat guilds respond to artificial light at night (ALAN) and assess how the impacts can vary according to ecological context. All studied European species respond negatively to ALAN close to roosts and drinking sites, and impacts occur across a wide range of light colours and intensities. Most bat species are sensitive to ALAN...
Article
Light pollution, light in the wrong place at the wrong time, is an emerging environmental issue with wide-ranging consequences. It interferes with the fundamental 24 h light–dark cycle, and has biological effects at all levels, from molecules to ecosystems, including human health and welfare. Here, exemplified by flood-lit churches, artificial ligh...
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Minimizing insecticide use, preventing vector diseases and facilitating biodiversity assessments are suitable applications of recent advances in photonic insect surveillance and entomological lidar. However, it is evident that lidars are subject to finite detection range given by the instrument noise and saturation levels, and therefore, intervals...
Article
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Wind turbines have considerable impact on flying animals, particularly bats, which are sometimes killed in large numbers by the moving rotors. A longstanding question remains why bats are attracted to wind turbines and risk their lives among the moving rotor blades. One hypothesis is that they feed on insects swarming around the turbine towers and...
Book
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Achtzig Prozent der Weltbevölkerung leben derzeit unter einem lichtverschmutzten Himmel, und die Milchstraße ist für mehr als ein Drittel der Menschheit nicht mehr sichtbar. Das Tempo, in dem die Lichtverschmutzung zunimmt, ist schneller als das globale Bevölkerungswachstum und die wirtschaftliche Entwicklung. Während sich die Umweltbedingungen in...
Article
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We monitored foraging insectivorous bats along walked transects in forest and farmland at Arabuko-Sokoke Forest in coastal Kenya, using a heterodyne bat detector. The main purpose was to test whether aerial-hawking insectivorous bats that feed in open places (in this case mostly Scotophilus and Scotoecus spp.) show lunar phobia, i.e. restricting th...
Book
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These guidelines explain how European bats respond to artifiical light at night and how the negative effects of artificial light at night can be mitigated when new street lamps are installed or when the type of lighting is changed, e.g. from conventional to energy efficient lighting schemes.
Article
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We need to know if and how western barbastelles Barbastella barbastellus are affected by wind farming in Sweden. This is because wind turbines are frequently constructed in barbastelle habitats and yet there is no national guideline on how the arising conflict should be handled. We studied the movement, behavior and mortality of a barbastelle popul...
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We present the results of, to our knowledge, the first Lidar study applied to continuous and simultaneous monitoring of aerial insects, bats and birds. It illustrates how common patterns of flight activity, e.g. insect swarming around twilight, depend on predation risk and other constraints acting on the faunal components. Flight activity was monit...
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Abstract. We highlight the use of the bat (Chiroptera) in the Florentine Renaissance art. Michelangelo Buonarrrroti, Bernardo Buontalenti, Albrecht Dürer and several others used images of bats in their sketches, sculptures and decorations and many bat images are still to be seen on the palaces and monuments in the Historic Centre of Florence, a UNE...
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We surveyed 110 country churches in south-western Sweden for presence of brown long-eared bats Plecotus auritus in summer 2016 by visual inspection and/or evening emergence counts. Each church was also classified according to the presence and amount of aesthetic directional lights (floodlights) aimed on its walls and tower from the outside. Sixty-o...
Data
Supplement “Age of enlightenment: long-term effects of artificial outdoor lighting on bats in churches”. Rydell et al. 2017.
Conference Paper
Full-text available
MOVEMENTS OF BARBASTELLE BATS AT A WIND FARM [O*] GRZEGORZ APOZNÁNSKI3**, TOMASZ KOKUREWICZ3, STEFAN PETTERSSON2, SONIA SÁNCHEZ-NAVARRO4, JENS RYDELL1, **apoznanski.grzegorz@gmail.com 1Biology Department, Lund University, SE-223 62 Lund, Sweden; 2EnviroPlanning AB, SE-411 04 Göteborg, Sweden; 3Wroclaw University of Environmental and Life Sciences,...
Conference Paper
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HABITAT SELECTION OF THE BARBASTELLE BAT (BARBASTELLA BARBASTELLUS) DURING LACTATION IN SWEDEN – PRELIMINARY RESULTS [P] TOMASZ KOKUREWICZ1**, GRZEGORZ APOZNÁNSKI1, STEFAN PETTERSSON2, SONIA SÁNCHEZ-NAVARRO3,4, JENS RYDELL4, **tkokur@gmail.com 1Wrocław University of Environmental and Life Sciences, Institute of Biology, Department of Vertebrate Eco...
Article
Echolocating bats are surveyed and studied acoustically with bat detectors routinely and worldwide, yet identification of species from calls often remains ambiguous or impossible due to intraspecific call variation and/or interspecific overlap in call design. To overcome such difficulties and to reduce workload, automated classifiers of echolocatio...
Article
We collected bat carcasses at three wind farms in Taiwan, located along the west coast mostly near the sea and/or in former coastal wetland habitats. We found 43 bat carcasses, mostly of common aerial-hawking species such as Pipistrellus abramus and Scotophilus kuhlii, but the island endemics Eptesicus serotinus horikawai and Myotis formosus flavus...
Article
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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 ri...
Article
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Bats are currently killed in large numbers at wind turbines worldwide, but the ultimate reason why this happens remains poorly understood. One hypothesis is that bats visit wind turbines to feed on insects exposed at the turbine towers. We used single molecule next generation DNA sequencing to identify stomach contents of 18 bats of four species (P...
Chapter
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Wind energy continues to be one of the fastest growing renewable energy sources under development, and while representing a clean energy source, it is not environmentally neutral. Large numbers of bats are being killed at utility-scale wind energy facilities worldwide, raising concern about cumulative impacts of wind energy development on bat popul...
Article
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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 Augus...
Article
Bats are mammals of chief conservation concern and also represent potentially powerful bio-indicators. Surveying bats is thus an important task but the approaches adopted may either be too invasive (capture) or prone to identification errors (acoustic methods). We here report on the use of a photographic trap to survey bat species richness we teste...
Article
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Active sensing, where sensory acquisition is actively modulated, is an inherent component of almost all sensory systems. Echolocating bats are a prime example of active sensing. They can rapidly adjust many of their biosonar parameters to optimize sensory acquisition. They dynamically adjust pulse design, pulse duration, and pulse rate within dozen...
Article
Full-text available
Active sensing, where sensory acquisition is actively modulated, is an inherent component of almost all sensory systems. Echolocating bats are a prime example of active sensing. They can rapidly adjust many of their biosonar parameters to optimize sensory acquisition. They dynamically adjust pulse design, pulse duration, and pulse rate within dozen...
Article
We explore the effects of biotic and abiotic factors on the population demography of frillneck lizards (Chlamydosaurus kingii) in the Australian wet-dry tropics. Annual growth rates of males were significantly higher across all body sizes compared to females, resulting in a significant larger maximum body size in males. Both male and female lizards...
Article
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...
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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 c...
Article
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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...
Article
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The echolocation calls of Rhychonycteris naso (Emballonuridae), Thyroptera tricolor (Thyropteridae), and Myotis riparius (Vespertilionidae) were recorded at the Cãno Palma Field Station in Costa Rica in February 1998. All three species produced echolocation calls at low duty cycle (signal on ~10% of the time). While T. tricolor produced low-intensi...
Article
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This note is based on a literature search and a recent review of bat mortality data from wind farms in Europe (published elsewhere). We suggest that mortality of bats at wind turbines may be linked to high-altitude feeding on migrating insects that accumulate at the turbine towers. Modern wind turbines seem to reach high enough into the airspace to...
Article
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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 rid...
Article
17 northern bats, comprising a maternity colony, were observed and recorded in their natural feeding habitat in southern Sweden. They searched for insects in more or less open habitats, 2–50 m above ground, and usually established individual feeding territories, which were patrolled in straight or slightly curved flight paths at rather constant alt...
Article
Echolocation calls from 10 individually marked female northern bats (Eptesicus nilssonii) were recorded as the bats foraged at three distinct feeding sites (territories) near their maternity roost in southern Sweden (57° N). In addition, recordings of unmarked bats were made in northern Sweden (65° N). The frequency at maximum amplitude of “search...
Article
A nursing colony of 26 Northern bats was studied in South-Central Sweden. The foraging behaviour is described with emphasis on social interactions on feeding grounds. The bats foraged in small feeding territories used night after night. The reproducing females defended feeding territories against other colony members as well as non-members by means...
Article
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Roads illuminated by white streetlamps attracted three times more foraging bats (mostly Pipistrellus pipistrellus) than did roads lit by orange streetlamps or unlit roads (3.2, 1.2 and 0.7 bat passes/km, respectively). More insects flew around white lamps than around orange lamps (mean 0.67 and 0.083 insects per lamp, respectively). The mean number...
Article
The diets of two fast-flying, aerial-hawking bats from north-east Africa (Ethiopia) were investigated by means of faecal analysis. Otomops martiensseni (Molossidae; c. 35 g body mass), which is remarkably specialized morphologically with very long, narrow wings and large ears, and which uses low frequency echolocation (10kHz), feeds almost exclusiv...
Article
The population density of the northern bat Eptesicus nilssoni at 65° N was about one-fifth of that in southern Sweden (57° N). No other bat species was observed at 65° N. In one maternity colony, young northern bats were born in July and were flying by early August. The diet consisted mainly of small insects, predominantly dipterans, which were cap...
Article
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The nymphalid butterfly Manataria maculata in the Monteverde cloud forest in Costa Rica moves daily between communal day roosts on the ground and individual night roosts in the trees. We studied these movements through an experimental setup where we exposed dead butterflies on the ground and in trees to natural predation for 24 h periods. M. macula...
Article
Foraging northern bats Eptesicus nilssoni were monitored from a car along a 27 km line transect in southern Sweden every week during a 14 month period by means of a bat detector. The number of bats observed along the transect was highly correlated with air temperature, and no bats were observed at temperatures < 6°C. Hence, feeding was infrequent i...
Article
The diet of Barbastella barbastellus was investigated through analysis of droppings collected from three maternity roosts in Germany and Switzerland. The results showed a high dominance of moths (Lepidoptera), which accounted for 73–94% of the recovered items by volume. Flies (Diptera), ranging in size from blow flies (Calliphoridae) and large cran...
Article
Northern bats foraged predominantly in small individual and transient feeding sites usually in open places near trees and over water. Lakes were preferred as foraging habitat as compared to woodlands and farmlands. The pattern of habitat selection did not change drastically during the period of reproduction. The diet was probably unselective, consi...
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Food habits of the parti-coloured bat in southern Sweden were investigated by analysis of fecal samples collected from three maternity roosts used in summer and, in addition, one roost used by a male during the mating season m autumn Small (c 3-10 mm) dipterans dominated all samples, representing 64-82% by volume, but larger flying insects like mot...
Article
The purpose of this study was to evaluate the impact of moonlight on the swarming activity of bats at an abandoned mine in southern Sweden. The mine serves as a hibernaculum for six species of insectivorous bats. Swarming activity at one of the mine entrances was measured on 12 nights between 1 August and 8 September 2000, by electronically countin...
Article
A small colony of little brown bats Myotis lucifugus was observed feeding on mosquitoes (Culicidae) inside a barn near Fairbanks, Alaska in June 2000. Observations were made visually and with a bat detector. All capture attempts were associated with feeding buzzes, indicating that the bats used echolocation to detect and track the insects, although...
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The northern bat Eptesicus nilssonii normally hunts flying insects in the air using frequency-modulated echolocation calls. It is also known to detect and catch visually conspicuous prey (white moths) hovering low among grass stalks. To overcome the problem with acoustic clutter from the grass, which interferes with target echo detection, the bats...
Article
Male small china-mark moth Cataclysta lemnata (Pyralidae) swarming over shallow water show a flight activity that peaks during the afternoon but which sometimes is extended into the night. We exposed wild, naturally flying C. lemnata to simulated predator attacks consisting of a) bursts of ultrasound (26 kHz, simulating a bat) and b) a thrown stick...
Article
Most larger nocturnal moths (“macrolepidoptera”) are equipped with ultrasonic tympanic organs (ears), which give them a considerable survival advantage in encounters with echolocating bats. However, 4.2% of the Scandinavian species lack such organs, and are presumably deaf. Our results show that the earless species are larger and have higher wing l...
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The crepuscular nymphalid butterfly Manataria maculata was studied in Monteverde cloud forest, Costa Rica, during the dry season reproductive diapause. M. maculata has ears in the form of Vogel's organs located near the base of the forewings. Its behaviour in response to bursts of ultrasonic pulses (26 kHz, 110 dB SPL at 1 m) was condition-dependen...
Article
We investigated the detection cues used by the aerial-hawking bat Eptesicus nilssonii foraging in a cluttered environment. The bats can detect and attack rapidly moving targets within the clutter, i.e. below grass panicles, by using prey motion as a cue. Stationary objects are attacked only above the grass, but still within the clutter overlap zone...
Article
1. Daubenton’s Bats (Myotis daubentonii) foraging over a stream concentrated their activity over calm surfaces, avoiding an adjacent area with small ripples (< 3 cm high). Aerial insects were most abundant over the ripples, so insect distribution could not explain why the bats avoided this area. 2. The bats flew low over water and always (N = 22) d...
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Our study showed that one species of water strider (Aquarius najas) dominated the insect fauna (>90% of the biomass) on and near the surface of a small stream in southern Sweden, but the diet of Daubenton's bats (Myotis daubentonii), regularly feeding over the same stream, contained <1% of these insects. To explain why the bats did not eat water st...
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The echolocation calls of insectivorous bats of the northern Yucatan Peninsula, Mexico, with the exception of the phyllostomids and molossids, are presented. The aim is to provide a catalogue of bat sounds that can be used for acoustic inventories of insectivorous bats using the Pettersson heterodyne and time expansion bat detectors. The acoustic m...
Article
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The spatial and temporal associations between Cruziana, trace fossils dug by foraging trilobites, and back filled burrows made by infaunal "worms" in a Lower Cambrian sandstone are described and discussed. In three large slabs and several smaller pieces, all from the same bedding plane in the lowermost part of the Mickwitzia sandstone (File Haidar...
Article
During the Swedish-Canadian icebreaker-based expedition to the Nearctic in summer 1999 (July and early August), moths and butterflies (Lepidoptera) were collected during short, helicopter-aided visits to eight sites in the Canadian archipelago, three sites on the Canadian mainland near the arctic coast and also at Thule Air Force Base in north Gree...
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We analysed the wing coloration of the orange underwing moth Archiearis parthenias (Geometridae, Archiearinae) in comparison with the small tortoiseshell butterfly Aglais urticae (Nymphalidae). Both species fly in early spring and occur sympatrically in the northern Palaearctic. Aglais, the more common species, has a longer flight period and uses a...
Article
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We studied the acoustic behaviour of bats (Eptesicus nilssonii) hunting for large (wing span 5 cm) non-hearing hepialid moths (Hepialus humuli). Groups of silvery-white male H. humuli perform a short (30 min) hovering display flight over grassland at dusk. They typically hover at, or below, the tops of grass panicles and are therefore situated in a...
Article
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We investigated the bat defence reactions of three species of moths (Gynaephora groenlandica, Gynaephora rossi (Lymantriidae) and Psychophora sabini (Geometridae)) in the Canadian Arctic archipelago. Since these moths inhabit the Arctic tundra and, therefore, are most probably spatially isolated from bats, their hearing and associated defensive rea...
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We investigated intraspecific differences in evening emergence time of northern bats Eptesicus nilssonii, greater horseshoe bats Rhinolophus ferrumequinum and lesser horseshoe bats R. hipposideros. Significant differences in emergence time were associated with presumed variation in predation risk, related to light intensity, and energetic benefits...
Article
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Previous studies suggest that many species of insectivorous bats are nocturnal, despite the relatively low availability of their insect prey at night, because of the risk of predation by diurnal predatory birds. We hypothesised that if this was the case bats living above the arctic circle would alter their feeding behaviour during midsummer because...
Article
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Polar angles (azimuth orientations) and vertical positions (convex side up or down) of cephala and pygidia of Agnostus pisiformis were recorded from 18 shale surfaces within a 0.85 m sequence of Upper Cambrian Alum Shale in Västergötland, Sweden. The absence of articulated specimens, and of thoracic segments, on the surfaces suggest that the agnost...
Article
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The echolocation calls of Rhychonycteris naso (Emballonuridae), Thyroptera tricolor (Thyropteridae), and Myotis riparius (Vespertilionidae) were recorded at the Ceno Palma Field Station in Costa Rica in February 1998. All three species produced echolocation calls at low duty cycle (signal on similar to 10% of the time). While T. tricolor produced l...