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The impact of artificial lighting on bats along native coastal vegetation


Abstract and Figures

Anthropogenic light pollution is increasing rapidly within urban areas around the world, causing a raft of ecological issues, including species loss. I used echolocation detectors to uncover the impact of artificial lighting on insectivorous bat (Chiroptera) species in Melbourne's southeast. Surveys were undertaken in native vegetation at a lit treatment, which was illuminated by a street light, and an unlit treatment, which was dark. Bat activity and species richness at unlit treatments was significantly higher when compared with lit treatments. The temperature at which the greatest activity occurred was ~2 C higher at unlit treatments than lit treatments. Bat activity at both the lit and unlit treatments increased rapidly after sunset. Bat activity moderately decreased during the night at lit treatments until sunrise, whilst activity at unlit treatments remained steady throughout the night before rapidly decreasing two hours before sunrise. The negative effect of artificial lighting on bat activity and species in urban areas may have major long-term implications on the ecology of urban areas.
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The impact of articial lighting on bats along native
coastal vegetation
Grant D. Linley
Ecological Insights, Black Rock, Vic., Australia. Email:
Abstract. Anthropogenic light pollution is increasing rapidly within urban areas around the world, causing a raft
of ecological issues, including species loss. I used echolocation detectors to uncover the impact of articial lighting on
insectivorous bat (Chiroptera) species in Melbournes south-east. Surveys were undertaken in native vegetation at a lit
treatment, which was illuminated by a street light, and an unlit treatment, which was dark. Bat activity and species richness
at unlit treatments was signicantly higher when compared with lit treatments. The temperature at which the greatest
activity occurred was ~2C higher at unlit treatments than lit treatments. Bat activity at both the lit and unlit treatments
increased rapidly after sunset. Bat activity moderately decreased during the night at lit treatments until sunrise, whilst
activity at unlit treatments remained steady throughout the night before rapidly decreasing two hours before sunrise. The
negative effect of articial lighting on bat activity and species in urban areas may have major long-term implications on
the ecology of urban areas.
Additional keywords: echolocation, insectivorous bats, lighting, urban ecology.
Received 10 November 2015, accepted 31 August 2016, published online 7 October 2016
There is a direct link between the impacts of humans and the
loss of biodiversity in urban areas (McKinney 2002,2008). As
urbanisation rapidly increases anthropogenic light pollution has
serious impacts on the functioning of ecosystems (Longcore and
Rich 2004; Hölker et al.2010). Much of the earth is now affected
by light pollution in some way, and this is thought to be increasing
by 6% per year (Elvidge et al.2001; Longcore and Rich 2004).
Over time, synergistic stressors place further pressure on these
heavily degraded and modied systems (Longcore and Rich
2004; Hölker et al.2010).
Landscape modication as a result of urban sprawl has
accelerated species loss in Australia (Fischer and Lindenmayer
2007), especially in coastal environments in or near urban areas
(Schlacher et al.2014). However, certain species, such as
insectivorous bats (hereafter bats), are able to persist in specic
urban areas (Avila-Flores and Fenton 2005; van der Ree and
McCarthy 2005; Hourigan et al.2010; Threlfall et al.2011).
Bats are nocturnal and play an important role in keeping urban
invertebrate species in balance (Hill and Smith 1984; Aldridge
and Rautenbach 1987; Gonsalves et al.2013). Each bat species
has specic foraging preferences that are associated with their
ight characteristics and mobility (Aldridge and Rautenbach
1987). Roosting sites are predominantly small dark spaces,
including tree hollows or small man-made hollows such as roof
holes (Tidemann and Flavel 1987; Lumsden et al.2002).
Anthropogenic lighting regimes affect bat feeding and
roosting behaviour (Scanlon and Petit 2008b; Lacoeuilhe et al.
2014;Day et al.2015). In one of Australias only studies on the
effects of light pollution on bats, Scanlon and Petit (2008b)
suggested that Nyctophilus geoffroyi and Chalinolobus morio
avoided all lit sites while Chalinolobus gouldii and Mormopterus
spp. prefer lighting. Some rare and cryptic bat species, including
Nyctophilus gouldi have been found to avoid light (Threlfall et al.
2013). Preference for lit areas is generally a result of higher
concentrations of insects and moths (Lepidoptera), which are
key components of the bat diet (Scanlon and Petit 2008a;
Lacoeuilhe et al.2014; Day et al.2015). The type of lighting
itself also determines what bats will be present. For example,
mercury vapour lamps attract moths and other insects more
than low pressure sodium lamps, whist LED lighting is known
to negatively impact certain species of bats (Rydell 1992; Blake
et al.1994; Stone et al.2012).
While there have been some studies of the effects of
articial lighting on bats (Rydell 1992; Scanlon and Petit
2008b;Stoneet al.2009;Threlfallet al.2013), there is no
information for the rapidly expanding Melbourne region. As
the local population and housing density increases, light
pollution increases (Cinzano et al.2001; Elvidge et al.2001).
It is essential to understand the effects of lighting on
insectivorous bats within urban environments in order to
mitigate them. With limited biodiversity remaining in urban
areas, preservation of what remains is key to maintaining
ecological processes (Fischer and Lindenmayer 2007). In this
study, I aimed to quantify the impacts of articial lighting on
bat species richness and activity.
The Author 2016
Australian Mammalogy
Study area
The study was conducted in the municipality of Bayside in
Melbournes south-eastern suburbs (Fig. 1). The area is highly
urbanised and predominantly consists of housing and roads. The
population is currently estimated to be 103 110 and in 2006 there
were 33 325 houses spread over 37 km
(Bayside Council 2007).
Small patches of remnant vegetation are scattered throughout
the area; most have lost their connectivity but may still be
functionally connected for most bat species. The municipality
includes a large strip of connected native vegetation along the
foreshore that has been only slightly modied through the
introduction of small numbers of non-native plants, walking
tracks and small fences. The local climate is characterised by
warm summers (maximum average temperature 25.2C) and
cool winters (maximum average temperature 14.3C) and an
average annual rainfall of 708.8 mm (Bureau of Meteorology
Bat surveys
Bat echolocation calls (hereafter calls) were recorded once
a month between December 2014 and March 2015 using Anabat
Express detectors (Titley Electronics, Ballina, NSW). Three
recording sites were established along a connected strip of
vegetation on the foreshore, and each was divided into two
treatments, lit and unlit. Lit treatment areas were illuminated
by mercury vapour street lights of 34 lx between sunset
and sunrise, while unlit treatment areas were not subject to any
articial lighting and illumination was less than 0.5 lx. All
treatments at each site had identical vegetation height and
structure, so the only discernible difference was the presence
of light. All sites were classed as coastal heathland scrub
(Ecology Australia 2008) and the dominant vegetation at each
site was coastal banksia (Banksia integrifolia), drooping sheoak
(Allocasuarina verticillata) and coastal tea tree (Leptospermum
laevigatum) with heights of 24 m. Sites were located at least
100 m from busy roads and major disturbances, including noise
pollution, and at least 50100 m from the ocean. At each site
treatments were 150250 m apart to ensure that bats could
access both the lit and unlit treatments. Each site was sampled
for three consecutive nights, using one Anabat detector in each
treatment, giving a total of nine sampling nights per month.
Sampling started 30 min before sunset and concluded 30 min
after sunrise. Surveys were not conducted on nights when rain
fell, when the temperature was below 10C or when wind
speeds were over 15 km h
. Surveys were not conducted within
ve days of a full moon, as moonlight affects bat activity and
detection (Basham et al.2011; Threlfall et al.2011).
The Anabat detectors where placed ~22.5 m off the ground
next to a yway to ensure consistency and accuracy when
sampling bats. In lit treatments the detector was located directly
below the light source. The omnidirectional microphone faced
horizontally to ensure that all calls in the vicinity of the unit
were detected. When a call was detected, the detector also
logged time and ambient temperature.
Call identication
Recordings were downloaded onto Analook (Titley Electronics,
Ballina, NSW), which allows the calls to be visualised and
identied. The principal parameters used for call identication
were frequency range and shape. Additionally, two guides
were used to assist in the identication of pulse characteristics
(Pennay et al.2004; Bat Sense 2010). Calls were analysed only if
they consisted of at least three pulses of a similar frequency
(Pennay et al.2004), and if there was any uncertainty about a call
it was not used in the analysis. Two species of little free-tailed
bats (Mormopterus sp. 2 and Mormopterus sp. 4) and two species
0510 km
Fig. 1. The locations of the three study sites (black squares) in relation to Australia (insert) and
BAustralian Mammalogy G. D. Linley
of long-eared bats (N. geoffroyi and N.gouldii) occur in this
area, but their calls could not be identied to species level
(Pennay et al.2004; Bat Sense 2010).
In addition to checking calls against guides, unknown calls
were sent to experts. It is not possible to identify all calls:
unrelated species may have similar calls and many bats vary
their calls in different habitats, so it is possible that a small
number of calls may be misidentied.
Statistical analysis
MannWhitney U-tests were used to determine the difference
between treatments for the total activity of all species identied
and differences between each individuals species at each
treatment. Resulting Pvalues were not corrected as species are
not correlated and the trade-off between decreasing Type 1 error
and increasing Type 2 error was deemed to be too great. A t-test
with unequal variance was used to test species richness between
the treatments over the sampling period. Single-factor ANOVAs
were used to determine if any differences existed between
months at each treatment and between sites over the whole
sampling period. The statistical program EstimateS was used to
produce sample-based rarefaction curves using a sample that
was randomised 100 times (Gotelli and Colwell 2001). Using
analysis software that allowed for the extraction of temperature
and time data from calls, the resulting differences in bat activity
of these variables for both lit and unlit treatments were
compiled and compared. To test for differences in activity levels
of both the temperature and time at treatments, two-sample
KolmogorovSmirnov tests were used.
Activity of bats
A total of 13 002 bat calls were recorded from 54 498 recordings,
the majority of recordings being insect calls and background
noise from wind. Of these calls, 10 112 (77.8%) were identied.
The total activity of bats was highest at unlit treatments, with
an overall 5905 identied calls compared with 4207 from the lit
treatments (Table 1). Over the whole study the average number
of calls per species at lit sites was 382.45 (284.01) compared
with 536.81 at unlit (352.38) (d.f. = 10, P= 0.046) (Table 1).
No signicant differences for C. gouldii,C. morio,Vespadelus
vulturnus,Austronomous australis,Miniopterus schreibersii
oceanensis. Saccolaimus aviventris was found between
treatments. For Mormopterus spp., Myotis macropus,Nyctophilus
spp., Vespadelus darlingtoni and Vespadelus regulus the total
numbers of calls in lit treatments were signicantly lower than in
unlit treatments (Table 1).
No differences were found to occur between the monthly
total for each species for both the lit (F
= 0.37, P= 0.77)
and unlit (F
= 0.05, P= 0.99) treatments. There were no
signicant differences in species totals between the three sites:
lit (F
= 0.33, P= 0.72), unlit (F
= 0.37, P= 0.69).
Difference in species richness
In total, 11 species were detected at the study area, 5 at lit
treatments and 11 at unlit treatments. Species richness was
signicantly lower at lit treatments (5 0.00) compared with
unlit treatments (10.33 0.67) at each site (d.f. = 2, P<0.01).
Sample-based rarefaction curves show the disparity in richness
between the lit and unlit treatments over the sampling period
(Fig. 2). As both curves reach an asymptote the ndings are
sufciently robust to compare (Gotelli and Colwell 2001;
Colwell et al.2004).
The effect of temperature on bat activity
Bat activity was strongly inuenced by ambient temperature
(Fig. 3). During the study period, nocturnal ambient temperature
varied from 10Cto32
C, and 81% of identied calls were
detected when ambient temperatures were 1323C. There were
no differences in ambient temperatures between the lit and unlit
treatments, but bat activity at lit treatments peaked between 13C
and 17C, while in the unlit treatments activity peaked between
14C and 19C (Fig. 3)(D
= 0.25, P= 0.01).
The inuence of time since sunset on bat activity
In all, 92% of calls from identied bat species were recorded
in the rst hour after sunset. Nocturnal bat activity was much
higher at unlit treatments compared with lit treatments (Fig. 4).
Table 1. The median calls and the total number of identied bat calls (in parentheses) for each species per treatment
over the study period
Results of MannWhitney U-tests are shown for each species between treatments
Unlit Lit MannWhitney U-tests
Austronomous australis (white-striped free-tailed bat) 63 (475) 47 (112) U=2,n
=3,P= 0.14
Chalinolobus gouldii (Goulds wattled bat) 1435 (4011) 530 (3143) U=4,n
=3,P= 0.41
Chalinolobus morio (chocolate wattled bat) 32 (182) 33 (99) U=4,n
=3,P= 0.41
Miniopterus schreibersii oceanensis (eastern bentwing-bat) 1 (33) 0 (0) U= 1.5, n
=3,P= 0.10
Mormopterus spp. (free-tailed bats) 100 (332) 35 (97) U=0,n
=3,P= 0.02
Myotis macropus (large-footed myotis) 1 (3) 0 (0) U=0,n
=3,P= 0.02
Nyctophilus spp. (long-eared bats) 1 (11) 0 (0) U=0,n
=3,P= 0.02
Saccolaimus aviventris (yellow-bellied sheath-tailed bat) 2 (6) 0 (0) U= 1.5, n
=3,P= 0.10
Vespadelus darlingtoni (large forest bat) 25 (120) 0 (0) U=0,n
=3,P= 0.02
Vespadelus regulus (southern forest bat) 61 (156) 0 (0) U=0, n
=3,P= 0.02
Vespadelus vulturnus (little forest bat) 256 (576) 30 (756) U=3,n
=3,P= 0.26
Total unidentied calls 324 (1197) 583 (1693) U=3,n
=3,P= 0.26
Total identied calls 5905 4207
Impacts of articial lighting on bats Australian Mammalogy C
Activity at both the lit and unlit treatments increased rapidly after
sunset; however, activity at the lit treatments quickly diminished
while activity at the unlit treatments remained high throughout
the night, and then declined before sunrise (Fig. 4). The difference
between the time in which bat activity occurred at lit and unlit
treatments was found to be signicantly different (D
= 0.08,
Articial lighting reduced both activity and species richness
of bats in the study area. The ambient temperature and time at
which peak activity occurred were also affected by lighting.
These results are in agreement with previous studies that found
that articial lighting reduced species richness and diversity
of bats (Scanlon and Petit 2008a,2008b; Stone et al.2009;
Lacoeuilhe et al.2014; Day et al.2015), but differ from other
studies that concluded articial lighting generally increased bat
activity (Blake et al.1994; Avila-Flores and Fenton 2005). This
suggests that the effect of articial light on bats is more complex
than anticipated and can vary between regions and species.
Loss of bat activity and richness
The species identied in this study are widespread throughout
south-eastern Australia (Pennay et al.2004; Bat Sense 2010)
and have previously been found to show little preference between
lit and unlit areas (Scanlon and Petit 2008a). Overall, in the
present study unlit treatments had signicantly higher bat
activity than lit treatments (Table 1). Of the species identied,
C. gouldii,S. balstoni,V. darlingtoni and V. vulturnus were
found to be generalist species with similar activity at both lit
and unlit treatments.
At lit treatments A. australis,C. morio,M. schreibersii
oceanensis,Mormopterus spp., M. macropus,Nyctophilus spp.,
S. aviventris,V. darlingtoni and V. regulus were not recorded,
and it is known that all are sensitive to both articial lighting
and urbanisation (Lumsden et al.2002; Scanlon and Petit 2008a;
Threlfall et al.2012). My results contrast with those of a
previous study in New South Wales that showed higher activity
of A. australis,S. aviventris and V. regulus at lit treatments
(Adams et al.2005). These species are believed to avoid lit
areas due to feeding requirements and morphology (Aldridge
and Rautenbach 1987; Furlonger et al.1987). All species
affected by articial lighting on the foreshore have large bodies
that are less manoeuvrable, except V. regulus (Bat Sense 2010).
The lack of manoeuvrability may force these species away from
lit areas as they are not able to capture their prey that are attracted
to the lights (Aldridge and Rautenbach 1987; Rydell 1992).
The impact of articial lighting on species richness within
the reserve is demonstrated by the sample-based rarefaction
curve comparison (Fig. 2). Both curves reached an asymptote so
it is reasonable to assume that all species within the area were
Number of samples
0 50 100 150 200
Fig. 2. Sample-based rarefaction curves calculated from all identied
species within the lit and unlit treatments over the study period.
Number of calls
Temperature (°C)
10 12 14 16 18 20 22 24 26 28 30
Fig. 3. Number of identied calls plotted against ambient temperature for
the lit and unlit treatments.
Number of calls
e of ni
0 102030405060708090
Fig. 4. The total activity of all identied bat species during the sampling
period over the percentage of the night between lit and unlit treatments.
Note that 0 corresponds to sunset and 100 corresponds to sunrise.
DAustralian Mammalogy G. D. Linley
detected (Gotelli and Colwell 2001). The results demonstrate
that anthropogenic light in urban areas can result in lower bat
species richness within and around illuminated areas (Scanlon
and Petit 2008b; Hourigan et al.2010). By limiting the use of the
foreshore area by some bat species, lighting may lead to local
The effect of temperature
The relationships between temperature and the nocturnal activity
seen in bats around the foreshore (Fig. 3) have been previously
noted in other studies (Avery 1985; Rydell 1991; Milne et al.
2005; Milne 2006). Optimal ranges for bat activity during this
study are similar to those found by previous studies (Milne et al.
2005), but the differences in activity peaks between treatments
have not been reported on (Fig. 3). The difference between the
optimal temperature for the activity of bats at lit and unlit
treatments is likely to be caused by articial lighting having
an effect on the availability and activity of insects at lower
temperatures (Rydell et al.1996; Milne et al.2005). Articial
sources of light interfere with insect navigation systems, causing
phototaxis (Scanlon and Petit 2008a), which causes high densities
of insects to congregate around light sources (Danthanarayana
and Dashper 1986; Rydell 1992; Blake et al.1994). It is possible
that articial lighting causes insects to become active at a lower
temperature which then attracts bats.
Bat activity is inuenced by the availability of prey, which is
regulated by temperature (Rydell 1992); hence, both bats and
prey are most active during the warmer months (Scanlon and
Petit 2008a). This coincides with bat breeding cycles as young
must accumulate fat before the cooler months (Tidemann 1993;
Van Dyck and Strahan 2008). Certain bat species decrease their
activity over the winter periods (Turbill et al.2003; Milne et al.
2005), and studies in Adelaide have found that C. gouldii and
Mormopterus spp. are less active during the cooler months
whereas A. australis and C. morio remained active (Scanlon and
Petit 2008a).
Activity throughout the night
Bat activity is commonly observed to increase rapidly after
sunset and then steadily decrease throughout the night, similar
to what was observed at lit treatments (Taylor and Oneill 1988;
Adams et al.2005; Milne et al.2005;Turbill2008). This
pattern of bat activity is largely driven by the activity of
insects, which are known to be most active after sunset in lit
areas before dispersing throughout the night (Swift 1980;
Danthanarayana and Dashper 1986; Taylor and Oneill 1988;
Richards 1989; Milne et al.2005). The activity proles at unlit
treatments appear to be very different from those found in
previous studies as the peak in activity occurs after sunset and
remains constant throughout the night before rapidly declining
before sunrise. The high activity at unlit treatments throughout
the night may be caused by the activity and density of insects
decreasing at lit treatments throughout the night due to
increased predation by bats or natural activity cycles of insects.
Bats that are not able to make use of increased insect densities
in lit areas may be forced to go in search of their prey in unlit
There have been several studies on the effects of articial lighting
on bats, but these have produced contradictory results. Articial
lighting reduced bat activity and species richness at all lit
treatments compared with unlit treatments, as has been observed
in some previous studies, whilst other studies have concluded that
lighting increases bat activity and species richness. All studies in
Australia have suggested that urbanisation and human-induced
disturbances have major implications for bat species richness.
Further increases in lighting installation will exacerbate the
existing negative impacts on bats. Where practicable and safe,
consideration should be given to sensor-activated lighting.
Councils should also consider minimising the use of mercury
vapour lighting, which attracts larger insect loads than low-
pressure sodium lamps. Caution must also be taken when
installing LED lighting as the impacts of this lighting type are not
fully understood. In areas of remnant vegetation in urban areas
that have lost connectivity to larger native areas, maintaining
unlit areas to allow for sufcient movement and exchange of
bats through the environment should be considered. Further
management and investigation should address the potential for
technological changes in the automatic illumination of public
areas, particularly patches of remnant vegetation, with the aim
of aiding the urban persistence of bats and their important
ecological functions.
Thanks to Bayside Friends of Native Wildlife, especially Elizabeth Walsh,
Anne Jessel and Michael Norris for their support and use of equipment.
Thanks to Denis Linley for help during eldwork. Thanks to Lindy Lumsden
and Tanja Straka for their help with bat identication. Anne Jessel provided
software to help with the analyses of bats. Thanks to Tristan OBrien, Calum
Cunningham, Tanja Straka, Caragh Threlfall, Rodney van der Ree, David
Marneweck, Professor Stewart Nicol and two anonymous reviewers who
provided helpful comments on improving this paper.
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Impacts of articial lighting on bats Australian Mammalogy G
... Abiotic factors influence animal behaviour, and moon phase, for example, can influence biological processes such as the timing of breeding, foraging and navigation (Pyle et al. 1993;Lang et al. 2006;Grant et al. 2009). Higher nocturnal illumination is associated with increased antipredator vigilance behaviour in sugar gliders (Petaurus breviceps) and artificial street lighting has been associated with reduced activity and richness of insectivorous bats (Barber-Meyer 2007;Nersesian et al. 2012;Linley 2017). ...
... During periods of low illumination (half and new moon) CWR predator species showed increased activity whereas medium-sized herbivore species showed less variation in activity in response to nocturnal illumination and cloud cover. Nocturnal illumination can negatively affect the activity of some mammals (Barber-Meyer 2007;Linley 2017), with the general consensus suggesting that prey are typically less active during periods of high lunar illumination, but conjecture exists (Lockard and Owings 1974;Clarke 1983;Prugh and Golden 2014). ...
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Moon phase and variation in ambient light conditions can influence predator and prey behaviour. Nocturnal predators locate prey visually, and prey may adjust their activity to minimise their predation risk. Understanding how native mammals in Australia respond to varying phases of the moon and cloud cover (light) enhances knowledge of factors affecting species’ survival and inference regarding ecological and population survey data. Over a two-year period within a fenced conservation reserve, in south-eastern Australia, with reintroduced native marsupial predator and prey species (eastern barred bandicoot, southern brown bandicoot, long-nosed potoroo, rufous bettong, Tasmanian pademelon, brush-tailed rock-wallaby, red-necked wallaby, eastern quoll, spotted-tailed quoll, and naturally occurring swamp wallaby, common brushtail possum, common ringtail possum), we conducted monthly spotlight surveys during different moon phases (full, half and new moon). We found an interaction between cloud cover and moon phase, and an interaction of the two depending on the mammal size and class. Increased activity of prey species corresponded with periods of increasing cloud cover. Predators and medium-sized herbivores were more active during times of low illumination. Our findings suggest that moon phase affects the nocturnal activity of mammal species and that, for prey species, there might be trade-offs between predation risk and foraging. Our findings have implications for: ecological survey design and interpretation of results for mammal populations across moon phases, understanding predator and prey behaviour and interactions in natural and modified (artificial lighting) ecosystems, and potential nocturnal niche partitioning of species.
... 11a Bavarian Nature Conservation Law). [53][54][55]57,102,[178][179][180]182,184,185,188,189,195,197,211,213,214,216,241,251,253,258,260,269,291,[302][303][304] 29 [53][54][55]57,[178][179][180]182,184,185,187,189,195,197,214,216,291,303,304] 19 ...
... 11a Bavarian Nature Conservation Law). [53][54][55]57,102,[178][179][180]182,184,185,188,189,195,197,211,213,214,216,241,251,253,258,260,269,291,[302][303][304] 29 [53][54][55]57,[178][179][180]182,184,185,187,189,195,197,214,216,291,303,304] 19 ...
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The fundamental change in nocturnal landscapes due to the increasing use of artificial light at night (ALAN) is recognized as being detrimental to the environment and raises important regulatory questions as to whether and how it should be regulated based on the manifold risks to the environment. Here, we present the results of an analysis of the current legal obligations on ALAN in context with a systematic review of adverse effects. The legal analysis includes the relevant aspects of European and German environmental law, specifically nature conservation and immission control. The review represents the results of 303 studies indicating significant disturbances of organisms and landscapes. We discuss the conditions for prohibitions by environmental laws and whether protection gaps persist and, hence, whether specific legislation for light pollution is necessary. While protection is predominantly provided for species with special protection status that reveal avoidance behavior of artificially lit landscapes and associated habitat loss, adverse effects on species and landscapes without special protection status are often unaddressed by existing regulations. Legislative shortcomings are caused by difficulties in proving adverse effect on the population level, detecting lighting malpractice, and applying the law to ALAN-related situations. Measures to reduce ALAN-induced environmental impacts are highlighted. We discuss whether an obligation to implement such measures is favorable for environmental protection and how regulations can be implemented.
... Uma das maiores causas da diminuição da população de morcegos é a perda de hábitat e de recursos por causa da urbanização e agricultura (KRAUEL; LEBUHN, 2016;BORDER et al., 2017;WORDLEY et al., 2017). Não é surpreendente que muitos estudos tenham demonstrado que essas formas de perda de hábitat, fragmentação e modificação tem um impacto negativo na atividade dos morcegos, na sua abundância e na sua diversidade (TRENTINI, 2005;FRICK et al., 2017;FSCHER;DIRZO, 2017;LINLEY 2017;KAHNONITCH;LUBIN;KORINE, 2018). Essa supressão dos habitats naturais ocasionou a extinção das espécies de quirópteros mais vulneráveis e com menor capacidade de adaptação (DEBINSKI; HOLT, 2000). ...
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A revista Terr@ Plural tem a missão de publicar artigos científicos relacionados à área de Gestão do Território que contribuam com o desenvolvimento do conhecimento teórico e metodológico deste campo de saber. Além disso, visa estimular o debate acadêmico daqueles que atuam na temática e ampliar as relações com profissionais de outras regiões do Brasil e do exterior. A revista é uma publicação semestral e é composta pelas seções de artigos e resenhas.
... Uma das maiores causas da diminuição da população de morcegos é a perda de hábitat e de recursos por causa da urbanização e agricultura (KRAUEL; LEBUHN, 2016;BORDER et al., 2017;WORDLEY et al., 2017). Não é surpreendente que muitos estudos tenham demonstrado que essas formas de perda de hábitat, fragmentação e modificação tem um impacto negativo na atividade dos morcegos, na sua abundância e na sua diversidade (TRENTINI, 2005;FRICK et al., 2017;FSCHER;DIRZO, 2017;LINLEY 2017;KAHNONITCH;LUBIN;KORINE, 2018). Essa supressão dos habitats naturais ocasionou a extinção das espécies de quirópteros mais vulneráveis e com menor capacidade de adaptação (DEBINSKI; HOLT, 2000). ...
... While fast-flying bats like pipistrelles and noctules show increased hunting activity around streetlights, slow-flying bats are rare or even absent from areas with illumination. The reasons are not clear yet, but while light-attraction is mostly explained by prey abundance, light aversion might be caused by increased predator risk or glare (Kuijper et al. 2008;Stone et al. 2012;Mathews et al. 2015;Spoelstra et al. 2017;Linley 2017;Azam et al. 2018;Russo et al. 2019). Indeed, light tolerant species are more active around metal halide lights than around sodium lights or LED, which correlates with the insect attraction of these light sources (Stone et al. 2015;Lewanzik and Voigt 2017;Straka et al. 2019;Haddock et al. 2019). ...
Technical Report
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Review on the current knowledge of the impact of artificial light on marine and coastal habitats with special focus on the Waddensea and intertidal areas.
... Indeed, elevated light pollution levels have been demonstrated to alter movement or act as movement barriers (for example with deer [Bliss-Ketchum et al., 2016, Ditmer et al., 2020, bats [Finch et al., 2020, hedgehogs [Berger et al., 2020, voles [Hoffmann et al., 2019 and mice (Rotics et al., 2011); as such, determining which mammals face the largest losses and fragmentation of dark environments is an important conservation consideration. Even if light pollution does not act as a barrier or prevent the use of otherwise quality habitat for a species, sensory disturbances can modify or reduce habitat quality by impacting orientation (e.g., songbirds; Cabrera-Cruz et al., 2018), decreasing foraging and hunting efficiency (e.g., insects; Bennie et al., 2015), increasing stress levels across taxa (Ouyang et al., 2018), delaying reproduction (e.g., wallabies and mice; Robert et al., 2015, Le Tallec et al., 2016, increasing vulnerability to predation (e.g., deer; Ditmer et al., 2020), and disrupting activity patterns (e.g., voles and bats; Hoffmann et al., 2018, Hoffmann et al., 2019, Linley, 2017 along with altering the vegetative communities within habitats (Giavi et al., 2020) and food webs (Manfrin et al., 2017). Previous work has assessed the changing coverage of light pollution over species' ranges using data from the Defense Meteorological Satellite Program (DMSP; Duffy et al., 2015, Koen et al., 2018. ...
A hallmark of the Anthropocene is the global expansion of pollution stemming from electric lighting. This evolutionarily novel phenomenon has left few spaces on Earth where natural light cycles remain unaltered. Assessing the exposure of species to light pollution is critical for developing conservation plans that address this expanding sensory pollutant. Here we used data from NASA's Visible Infrared Imaging Radiometer Suite to determine the contribution of full moonlight radiance to establish an ecologically-informed threshold of natural radiance. Using the geographic ranges of 351 mammals across the contiguous United States, we estimated the percentage of each species' range in which light pollution exceeded thresholds associated with direct emissions and skyglow, where it did not ("dark environment"), and the associated fragmentation of dark environments. Average mammal range contained 2.6% (95% CI: 2.3-3.2%) of area that consistently exceeded full moon radiance at point-source emissions, but with a large range among species (0-47.4%). Skyglow affected far greater percentages of ranges (X = 24.3%; 95% CI: 22.1-26.8%). Nocturnal species had slightly greater exposure than diurnal species. Several families with the most impacted ranges included species of conservation concern (e.g., Molossidae; free-tailed bats). When assessing connectivity of dark environments, we found light pollution fragmented most mammal ranges and resulted in isolated dark refugia (e.g., 154% average increase in patches of dark environments). Identifying species with the greatest exposure to and dark environment fragmentation from light pollution is an important step for targeted conservation efforts of remaining dark refugia for light-sensitive species.
... One major cause of global declines in bat populations continues to be the loss of habitat and critical resources through urbanization, intensive agricultural and forestry procedures, and land-use change (Krauel and LeBuhn 2016;Border et al. 2017;Wordley et al. 2017). Not surprisingly, many studies have shown that these forms of habitat loss, fragmentation, and modification have negatively impacted bat activity, abundance, and diversity (Frick et al. 2017;Goncalves et al. 2017;Linley 2017;Kahnonitch et al. 2018). To minimize and reduce these impacts, wildlife practitioners have three broad options: 1) restore habitat, 2) prevent further habitat loss and degradation, and 3) improve existing habitat, including anthropogenically dominated areas (Threlfall et al. 2017;Gallo et al. 2018;Suarez-Rubio et al. 2018). ...
Habitat loss has caused bat populations to decline globally and urbanization represents a major contributor to this loss. Yet, recent studies have indicated that urban parks can support a diverse and abundant bat community. These anthropogenically dominated areas must be providing readily available, potentially unconventional, resources. Identifying such resources could therefore give insight into how we can effectively improve urban habitat for bats. Thus, we investigated the use of residential swimming pools by bats as a water resource in behavioral surveys. We also used acoustic activity to determine species presence and identify trends in activity. We recorded 274 bats drinking at swimming pools from April to September 2016. We also acoustically identified all species present in the area. Furthermore, among pools closest to the park (< 200 m), bats only drank as the summer progressed, which corresponded to more “natural” sources in the park becoming less accessible. The quality of swimming pools may dictate their use and if we can identify features that influence quality, these insights may be used to improve resource availability for urban bats.
... Uma das maiores causas da diminuição da população de morcegos é a perda de hábitat e de recursos por causa da urbanização e agricultura (KRAUEL; LEBUHN, 2016;BORDER et al., 2017;WORDLEY et al., 2017). Não é surpreendente que muitos estudos tenham demonstrado que essas formas de perda de hábitat, fragmentação e modificação tem um impacto negativo na atividade dos morcegos, na sua abundância e na sua diversidade (TRENTINI, 2005;FRICK et al., 2017;FSCHER;DIRZO, 2017;LINLEY 2017;KAHNONITCH;LUBIN;KORINE, 2018). Essa supressão dos habitats naturais ocasionou a extinção das espécies de quirópteros mais vulneráveis e com menor capacidade de adaptação (DEBINSKI; HOLT, 2000). ...
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As cidades médias brasileiras precisam ser mais amigáveis aos morcegos, principalmente nos hotspots de biodiversidade Las ciudades medias de Brasil necesitan ser más amigables a los murciélagos, principalmente en los hotspots de biodiversidad Brazilian medium-sized cities need to be more friendly for bats, mainly on biodiversity hotspots Resumo: Atualmente mais da metade da população mundial vive em cidades e este número deve chegar a 72% até 2050. No Brasil, o processo de urbanização do território, geralmente rápido e sem planejamento, origina uma miríade de impactos ambientais. A urbanização faz declinar a riqueza e diversidade de espécies. Por outro lado, algumas espécies se adaptam aos ambientes antropogênicos pois obtêm vantagens da matriz urbana, utilizando-se de abrigo ou alimento disponíveis. Os morcegos possuem uma plasticidade ecológica que os permite estabelecerem-se em remanescentes florestais nas cidades ou diretamente no meio construído. Nesse ensaio, nós defendemos a importância das cidades médias como espaços de conservação da biodiversidade. Palavras-chave: quirópteros; urbanização; biodiversidade urbana; ecologia urbana. Resumen: Actualmente, más de la mitad de la población mundial vive en ciudades y se espera que este número alcance el 72% para 2050. En Brasil, el proceso de urbanización del territorio, generalmente rápido y no planificado, causa una gran cantidad de impactos ambientales. La urbanización hace que la riqueza y diversidad de las especies disminuyan. Por otro lado, algunas especies se adaptan a los ambientes antropogénicos porque obtienen ventajas de la matriz urbana, utilizando refugio o alimentos disponibles. Los murciélagos tienen una plasticidad ecológica que les permite establecerse en los restos de bosques en las ciudades o directamente en el entorno construido. En este ensayo, defendemos la importancia de las ciudades medianas como espacios para la conservación de la biodiversidad. Palabras clave: quirópteros; urbanización; biodiversidad urbana, ecología urbana.
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Natural light cycles are being eroded over large areas of the globe by the direct emissions and sky brightening that result from sources of artificial night-time light. This is predicted to affect wild organisms, particularly because of the central role that light regimes play in determining the timing of biological activity. Although many empirical studies have reported such effects, these have focused on particular species or local communities and have thus been unable to provide a general evaluation of the overall frequency and strength of these impacts. Using a new database of published studies, we show that exposure to artificial light at night induces strong responses for physiological measures, daily activity patterns and life history traits. We found particularly strong responses with regards to hormone levels, the onset of daily activity in diurnal species and life history traits, such as the number of offspring, predation, cognition and seafinding (in turtles). So far, few studies have focused on the impact of artificial light at night on ecosystem functions. The breadth and often strength of biological impacts we reveal highlight the need for outdoor artificial night-time lighting to be limited to the places and forms—such as timing, intensity and spectrum—where it is genuinely required by the people using it to minimize ecological impacts.
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We monitored echolocation calls to measure the activity of insectivorous bats at study sites in southwestern Ontario during the summer of 1985, relying on feeding buzzes to identify foraging activity. Eptesicus fuscus was the most common and widespread species in the area, while Lasiurus cinereus and Lasiurus borealis were widespread. Species in the genus Myotis were more restricted in their distribution, being more common in an area with potential hibernacula. None of the species foraged exclusively in one habitat and all species exploited concentrations of insects around lights. Only E. fuscus made significant use of lights as foraging sites in urban areas while in town and rural areas all of the species foraged around lights.
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The flight activity of three species of insectivorous bats and their prey was studied in north-east Scotland (57 degrees N) during summer 1993. Aerial insects of sizes taken by bats were more abundant during the day than during the night, but the highest abundance usually occurred around dusk, partly reflecting increased flight of dipterans. In contrast, the flight activity of moths, mainly Geometridae and Pyralidae, was greatest around midnight. Two species of aerial-hawking bats, Pipistrellus pipistrellus and Myotis daubentonii, which feed primarily on small flying insects, mainly Diptera, emerged from their roosts 15-30 min after sunset, during or after the dusk peak in insect activity, and subsequently foraged as their food was declining in abundance. In contrast, the foliage gleaning bat Plecotus auritus, which feeds primarily on moths, did not emerge until about one hour after sunset, but while the activity of its main prey was increasing. The two aerial-hawking bats therefore seem to be constrained from exploiting most of the evening peak in aerial insect abundance, presumably because earlier emergence would result in higher predation risk at the higher light levels. P. auritus may have less to gain by emerging early, since it can feed on moths and non-flying prey independently of the activity of small insects at dusk. The conclusions have implications for the conservation of bats and their habitats particularly at high latitudes. Protective tree cover may allow earlier evening emergence of bats and therefore provide access to more food.
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Anthropogenic light pollution is an increasingly significant issue worldwide. Over the past century, the use of artificial lighting has increased in association with human activity. Artificial lights are suspected to have substantial effects on the ecology of many species, e.g., by producing discontinuities in the territories of nocturnal animals. We analyzed the potential influence of the intensity and type of artificial light on bat activity in a semi-natural landscape in France. We used a species approach, followed by a trait-based approach, to light sensitivity. We also investigated whether the effect of light could be related to foraging traits. We performed acoustic surveys at sites located along a gradient of light intensities to assess the activity of 15 species of bats. We identified 2 functional response groups of species: one group that was light-tolerant and one group that was light-intolerant. Among the species in the latter group that appear to be disadvantaged by lighting conditions, many are rare and threatened in Europe, whereas the species from the former group are better able to thrive in disturbed habitats such as lighted areas and may actually benefit from artificial lighting. Finally, several methods of controlling light pollution are suggested for the conservation of bat communities. Recommendations for light management and the creation of dim-light corridors are proposed; these strategies may play an important role in protecting against the impact of light pollution on nocturnal animals.
The possibility that night-flying insects may use naturally polarized light as a cue for flight, dispersal, migratory activities and for orientation during movements (at night) has rarely been considered. The reason for this neglect may well be the belief that the amounts of polarized light that are available to insects at night are too small to influence them. During recent investigations on the flight activity of the mosquito Culex pipiens australicus (Dobrotworsky and Drummond) and the moths Plutella xylostella (L.) and Epiphyas postvittana (Walk.), it was found that there are three peaks of flight activity during the lunar cycle (Danthanarayana 1976, this volume; Goodwin and Danthanarayana 1984). Two of these peaks correlated with the degree of polarization of moon light (which increases at the first and last quarters) and the third occurred at the time of full moon when moonlight is more intense, but less polarized. It is not known, however, whether the correlation between the degree of polarization of moonlight and the amount of flight activity is a cause-and-effect relationship. As a preliminary step towards resolving this problem, the response of night-flying insects to polarized light was examined with the aid of light traps, activity-meter studies and by histological determination of the pigment position of superposition eyes of moths. Moths were selected for laboratory experiments because there is much published work in the eyepigment movements of this group (see below); in previous studies more Lepidoptera have been trapped under polarized light than under nonpolarized light (Kovrov and Monchadskiy 1963) and observations on the light-brown apple moth, Epiphyas postvittana, suggested the existence of profound restlessness (Zugunruhe) during the above phases of the moon (unpublished information). Results obtained during these studies, as reported below, confirm that some night-flying insects respond to dimpolarized light to a greater extent than to nonpolarized light of the same intensity.
Landscape modification and habitat fragmentation are key drivers of global species loss. Their effects may be understood by focusing on: (1) individual species and the processes threatening them, and (2) human-perceived landscape patterns and their correlation with species and assemblages. Individual species may decline as a result of interacting exogenous and endogenous threats, including habitat loss, habitat degradation, habitat isolation, changes in the biology, behaviour, and interactions of species, as well as additional, stochastic threats. Human-perceived landscape patterns that are frequently correlated with species assemblages include the amount and structure of native vegetation, the prevalence of anthropogenic edges, the degree of landscape connectivity, and the structure and heterogeneity of modified areas. Extinction cascades are particularly likely to occur in landscapes with low native vegetation cover, low landscape connectivity, degraded native vegetation and intensive land use in modified areas, especially if keystone species or entire functional groups of species are lost. This review (1) demonstrates that species-oriented and pattern-oriented approaches to understanding the ecology of modified landscapes are highly complementary, (2) clarifies the links between a wide range of interconnected themes, and (3) provides clear and consistent terminology. Tangible research and management priorities are outlined that are likely to benefit the conservation of native species in modified landscapes around the world.
Only the fast-flying bat species that use long-range echolocation systems (Nyctalus noctula, Vespertilio murinus, Eptesicus nilssonii and occasionally Pipistrellus pipistrellus) forage around streetlamps, whereas Myotis spp. and Plecotus auritus did not. Bat density along illuminated roads was 1-5 km-1. Over 90% of the bats detected were E. nilssonii. In and around a small town, E. nilssonii was predominantly found in residential and rural parts, and avoided areas without trees. Vespertilio murinus was observed in all habitats, a difference probably related to differences in the foraging behaviour of the two species. Various lamp types attracted insects in relation to the amount of short wave-lengths emitted. Bats were attracted to the lamp types as insects. The gross energy intake of E. nilssonii foraging around streetlamps was more than twice as high (0.5kJ min-1) as previously recorded in woodlands (0.2kJ min-1) but slightly lower than over pastures where dung beetles occurred (0.6kJ min-1). -from Author
Artificial nighttime lighting has many effects on biodiversity. A proposed environmental management option, primarily to save energy, is to alter the duration of night lighting. Using the greater horseshoe bat Rhinolophus ferrumequinum as an example of a photophobic species, we explored roadside behaviour patterns throughout the night to assess the potential impact of part-night lighting. We found a large primary peak in activity 1 h after sunset, followed by a smaller secondary peak before sunrise. Simulated part-night lighting scenarios reveal that to capture a large proportion of bat activity, streetlights should be switched off before midnight. Current proposed uses of part-night lighting are unlikely to capture natural peaks in activity for nocturnal species.
(1) Two hypotheses are tested in this paper: (i) wing morphology and echolocation-call `design' can determine foraging site selection and foraging behaviour in bats, (ii) echolocation-call `design' should be compatible with wing morphology (because some combinations of morphology and echolocation call would be maladaptive). (2) In support of our first hypothesis, significant correlations were established between wing morphology, echolocation call design, manoeuvrability and habitat use. (3) In support of our second hypothesis, significant correlations were established between those morphological parameters that improve manoeuvrability (low wingloading, low aspect ratio and high wingtip shape index) and echolocation calls that are resistant to acoustic clutter in support of our second hypothesis. (4) There was an association between foraging habitat and diet: bats that fed in the same habitats tended to take the same types of prey, while species foraging in different habitats had significantly different diets. (5) There was also a significant correlation between prey and predator size; large bats took insects over a range of sizes while small bats fed only on small prey.
Context. Conservation of insectivorous bat populations requires appropriate management of foraging habitats and the prey resources they sustain. Endangered coastal saltmarsh communities support a diverse range of aquatic and terrestrial arthropods, including the saltmarsh mosquito (Aedes vigilax Skuse), an important vector of mosquito-borne viruses and a potentially important prey resource for insectivorous bats. Prey detectability by bats is considered to be limited with low-frequency echolocation, particularly in cluttered habitats, that may render abundant Ae. vigilax populations unavailable to some bat species. Aims. To investigate relationships between availability of Ae. vigilax and non-mosquito prey, and the activity of foraging insectivorous bats in a range of coastal habitats. Methods. We measured nightly bat activity and the abundance of prey (mosquito and non-mosquito) concurrently during neap and spring tides in saltmarsh, urban and forest habitats. Comparisons were made between tidal cycle and habitats, and relationships between bat activity and the abundance of prey were examined. Key results. Whereas prey abundances were generally greatest in saltmarsh and forest habitats, bat activity was greatest in the forest habitat. However, proportional feeding activity was greatest in saltmarsh. Prey abundance was positively correlated with total bat activity only in the open saltmarsh, where an absence of clutter would maximise prey detectability and thus availability. Positive correlations between Ae. vigilax abundance and bat activity, across all habitats, were restricted to bats of the Vespadelus genus, which are small-sized bats that employ high-frequency echolocation suitable for detection of small prey along edges. Conclusions. These findings suggest that Ae. vigilax may be an important prey resource for small, high-frequency echolocating bats capable of discerning small prey within cluttered forest as well as exploiting abundant prey in the open saltmarsh. Implications. Small, high-frequency echolocating bats should be the focus of future studies investigating the importance of small prey, such as Ae. vigilax, to the diets of foraging bats.
Beaches and dunes of the open coast form one of the globe's longest ecological interfaces, linking the oceans with the land. These systems are of great importance to society as prime sites for housing and recreation, buffers against storms, and providers of fisheries and mineral resources. By contrast, their unique ecological attributes and biodiversity are much less recognized. In this chapter, we provide a synthesis of the key ecological features and functions of beaches and dunes, outline the main elements of their faunal biodiversity, examine human threats and their biological con-sequences, and sketch some salient issues in management to achieve conservation of these unique ecosystems. It is apparent that the range of ecosystem goods and services is broad, but nutrient cycling, water filtration and the provision of habitat and prey for a diverse range of animals are often the key ecological traits. Contrary to common perceptions, beaches and dunes contain a diverse and unique set of species, many of which are found nowhere else. In addition to the complement of highly adapted inverte-brates, many wildlife species (e.g. birds, turtles, fishes) are dependent on beaches and dunes for nesting and feeding, and they use these habitats extensively. Human pressures on sandy shorelines and their biodiversity are numerous. Coastal squeeze is, however, the most pervasive, trapping beaches and their biota between the pressures of development from the terrestrial side and the consequences of climate change from the marine side. Beaches are also naturally malleable habitats whose interlinkages, including the exchange of organisms, with the abutting dunes and surf Coastal Conservation, eds B. Maslo and J.
Artificial lighting is a key biodiversity threat and produces 1900 million tonnes of CO2 emissions globally, more than three times that produced by aviation. The need to meet climate change targets has led to a global increase in energy‐efficient light sources such as high‐brightness light‐emitting diodes (LEDs). Despite the energetic benefits of LEDs, their ecological impacts have not been tested. Using an experimental approach, we show that LED street lights caused a reduction in activity of slow‐flying bats ( Rhinolophus hipposideros and Myotis spp.). Both R. hipposideros and Myotis spp. activities were significantly reduced even during low light levels of 3.6 lux. There was no effect of LED lighting on the relatively fast‐flying Pipistrellus pipistrellus, Pipistrellus pygmaeus and Nyctalus/Eptesicus spp. We provide the first evidence of the effects of LED lights on bats. Despite having considerable energy‐saving benefits, LED lights can potentially fragment commuting routes for bats with associated negative conservation consequences. Our results add to the growing evidence of negative impacts of lighting on a wide range of taxa. We highlight the complexities involved in simultaneously meeting targets for reduction of greenhouse gas emissions and biodiversity loss. New lighting strategies should integrate climate change targets with the cultural, social and ecological impacts of emerging lighting technologies.