Diel activity of insectivorous bats in response to land-use change in São Tomé Island, Gulf of Guinea

doi:10.21203/rs.3.rs-4437801/v1

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Diel activity of insectivorous bats in response to land-use change in São Tomé Island, Gulf of Guinea

https://doi.org/10.21203/rs.3.rs-4437801/v1

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Land-use change poses a significant threat to biodiversity, particularly in insular ecosystems where species exhibit higher levels of specialisation. Despite the importance of tropical islands for biodiversity conservation, the impacts of land-use change on the diel activity of insular species remain poorly understood. We addressed this gap by investigating the diel activity patterns of insectivorous bats in response to land-use change in São Tomé Island, Central West Africa. Using passive acoustic detectors, we surveyed insectivorous bats across forests, shaded plantations, oil palm plantations, agricultural and urban areas. We examined (1) how intraspecific diel activity varies between forest and human-altered land-use types, and (2) how interspecific diel activity varies within the same land-use type, by quantifying overlap coefficients in species activity. Based on 19,383 bat passes from four species, we found that the degree of overlap in species-specific activity between forests and human-altered land-use types varied between species, with the least overlap being observed between forests and urban areas for Miniopterus newtoni, and between forests and oil palm plantations for Chaerephon spp.. Overlap in the activity of different species was lower within less or not disturbed land-use types (forests and shaded plantations), where more species were present. Overall, diel activity of insectivorous bats altered according to the magnitude of structural land-use change. Such bat responses might be eventually due to the different temporal prey availability and interspecific competition in the altered land-use types. These findings comprise baseline knowledge informing evidence-based management actions across tropical island systems.

Activity patterns

Chiroptera

Hipposideros ruber

habitat change

temporal overlap

tropical forests

Human-induced land-use change is a leading driver of biodiversity loss worldwide (Gonçalves-Souza et al. 2020; Powers and Jetz 2019) and its impacts are particularly acute in insular ecosystems, where species tend to exhibit greater physical and behavioural specialisation compared to their mainland counterparts (Kier et al. 2009). Yet, although islands host a disproportionate share of the planet’s threatened terrestrial vertebrates (ca. 40% of the species in < 8% of the planet’s land area; Fernández-Palacios et al. 2021), we still have a poor understanding of how insular taxa cope with the conversion of natural ecosystems into anthropogenic habitats such as agricultural areas and urban spaces.

Species persisting in the aftermath of land-use change are typically characterised by their ability to adapt their behaviour to new environmental conditions (Hedenström 2008; Mazza et al. 2020; Tranquillo et al. 2023). Species can adjust their activity patterns based on the time of day, environmental cues, and physiological needs and as such, alterations in activity patterns and partitioning along the temporal niche axis may be particularly insightful about species’ responses to habitat conversion (Ikeda et al. 2016; Monterroso et al. 2014). In fact, under increased human activity (Bogdan et al. 2016; Gaynor et al. 2018; Oberosler et al. 2017), or following shifts in the habitat structure, species are commonly observed to change their activity patterns (Díaz-Ruiz et al. 2016). Understanding species diel activity therefore offers valuable insights into overall behaviour (Weinbeer et al. 2006), foraging strategies (Laidlaw and Wan Noordin 1998), and intra and inter-species interactions (Gelmi-Candusso et al. 2023). Accordingly, this often-overlooked component of species ecology is greatly important for assessing a species’ adaptability to human-induced environmental changes (Frey et al. 2017).

Of the 1,400 bat species worldwide, over 60% inhabit islands and 25% are entirely restricted to island systems (Conenna et al. 2017; Vincenot et al. 2017). Therefore, islands are important ecosystems for bats. Yet, despite the key ecological roles played by insular bats (e.g., seed dispersal and arthropod suppression; Florens et al. 2017; Gonçalves et al. 2024; Kemp et al. 2019), they lag their mainland counterparts in terms of research attention (Conenna et al. 2017). Fortunately, the increasing availability of affordable passive acoustic detectors now allows for more comprehensive island surveys of echolocating bats (e.g., Ferreira et al. 2022; Nóbrega et al. 2023), offering an opportunity to investigate how anthropogenic stressors impact insular bat communities more thoroughly. An increasing body of literature is adding support that echolocating bats are highly responsive to anthropogenic land-use change (Hazard et al. 2023; Huang et al. 2019; Rodríguez-San Pedro et al. 2019), though studies concerning African bats remain limited (Meyer et al. 2016). Moreover, to date, most research tends to examine responses in terms of changes in occupancy and activity metrics (e.g., Rowley et al. 2024; Shapiro et al. 2020), limiting our understanding of more subtle behavioural responses to habitat disturbances.

In mainland bats, changes in the diel activity patterns of bats in response to anthropogenic land-use change are less pronounced in habitats with a higher structural similarity to old-growth forests, such as reduced-impact logged (Castro-Arellano et al. 2009; Presley et al. 2009b) and secondary forests (Appel et al. 2021), compared to agricultural (Presley et al. 2009a) and urban areas (Montaño-Centellas et al. 2015). In some island habitats, the absence of diurnal avian predators, such as hawks and falcons, allows some bat species to expand their diel temporal niche and be active during daytime (Chua and Aziz 2018; Russo et al. 2011). In these settings, the peculiar activity patterns of insular bats could potentially help mediate how land-use change impacts their daily activity budget. However, no study has yet analysed how the activity patterns of insular bats are affected by anthropogenic land-use change.

Here, we examined how the diel activity of insectivorous bats responds to land-use change in the endemic-rich Island of São Tomé, in Central West Africa. The Island was human-colonised in the late-15th century (Muñoz-Torrent et al. 2022). Since then, large tracts of its forest have been converted into cocoa and coffee plantations, mostly shaded by exotic trees (Muñoz-Torrent et al. 2022). Today, São Tomé has lost up to 75% of its native habitats to shaded plantations, organic oil palm plantations, small-scale agriculture, and urban areas (Dauby et al. 2022). Seven insectivorous bat species are known to occur in São Tomé, including three endemics: Macronycteris thomensis, Chaerephon tomensis and Miniopterus newtoni (Rainho et al. 2022). At least one species, Hipposideros ruber, is known to exhibit diurnal activity (Russo et al. 2011). Using passive acoustic recorders, we surveyed insectivorous bats across the island’s main land-use types: forests (including old-growth and secondary re-growth forests), oil palm plantations, agriculture, and urban areas. We then examined hourly activity patterns of the four most detected species (Macronycteris thomensis, Miniopterus newtoni, Chaerephon spp. and Hipposideros ruber) and investigated the temporal overlap between species within each surveyed habitat, and within the same species across different land-use types. Specifically, we aimed to address the following questions:

How does the diel activity of each bat species vary between forest and human-altered land-use types? We expect intraspecific activity patterns to differ the most between more structurally complex forests and more open land-use types such as agricultural areas and urban areas (Montaño-Centellas et al. 2015; Presley et al. 2009a)

How does the diel activity of different bat species overlap within the same land-use type? Since bats use temporal partitioning to reduce competition (Lambert et al. 2018), we anticipate lower temporal overlap among species in land-use types harbouring a higher diversity of bat species richness, namely in forests and shaded plantations.

Study area

Data collection was carried out in São Tomé Island, part of Democratic Republic of São Tomé and Príncipe, in the Gulf of Guinea off the western equatorial coast of Central Africa (Fig. 1). São Tomé experiences two distinct dry and rainy seasons, with average annual temperatures ranging from 27°C near sea level to 21°C at higher elevations. Annual precipitation varies from 900 mm in the northeast to around 6,000 mm in the south (Lima and Oliveira 2017). The Island has a rugged mountainous topography, with Pico de São Tomé being the highest point at 2024 m a.s.l.. The Island is further characterised by tropical forests falling within the ecoregion of São Tomé, Príncipe, and Annobón moist lowland forests (Burgess et al. 2004). The Ôbo Natural Park, a substantial conservation area spanning approximately 235 km² of mostly old-growth forests, covers 27% of the island’s area. The rest of the Island has a diversity of land-use types with varying levels of human disturbance, ranging from secondary forests (i.e., re-growth forests following the abandonment of mostly cocoa plantations), shaded plantations, oil palm plantations, agricultural areas, and urban areas (Dauby et al. 2022). Old-growth forests are characterised by relatively low levels of human intervention and nowadays are mostly confined to higher altitudes. Secondary re-growth forests are occupied by both native and non-native species, resulting from vegetation regrowth after the removal of the original forest. Shaded plantations involve cultivating crops (particularly cocoa) beneath a canopy of mostly exotic trees. Oil palm plantations are managed organically and restricted to the southern part of the island. Small-scale agricultural areas include crops such as banana trees, cassava, carrots, and tomatoes. Urban areas refer to human settlements.

Sampling design

Bats were surveyed across 115 sampling sites, with 13 sites located in old-growth forests, 17 in re-growth forests, 29 in shaded plantations, 20 in oil palm plantations, 23 in agricultural areas, and 13 in urban areas. Surveys took place between August and September 2022 to minimise rain-related impact on both bat activity and equipment performance. The sampling site location aimed to cover as much of the island area as possible, which was limited by difficulties in accessing remote areas. Each site was sampled using one AudioMoth device (Hill et al. 2018) that recorded one minute out of every five minutes for 48 consecutive hours at mid-gain with a 384 kHz sample rate. The diurnal recording was intended to capture the diurnal activity of Hipposideros ruber (Russo et al. 2011). Contiguous sampling sites were at least 250 m apart to minimise simultaneously recording the same individual (Ferreira et al. 2022). AudioMoth devices were placed inside waterproof boxes and attached to vertical structures, between 1.5 and 2 m above the ground (López-Bosch et al. 2022). A total of 20 spatially aggregated sampling sites were surveyed at the same time.

Canopy cover was estimated at each site through visual assessment by determining the percentage of cover above the AudioMoth. The old-growth and re-growth forests represented relatively undisturbed areas with similar canopy cover (Table S1). Therefore, and due to the low number of bat detections in old-growth forests alone, these two categories were merged for the analysis, henceforth referred to simply as forests.

Bioacoustics analysis

Our unit to measure bat activity was the bat pass, defined as a sequence of two (or more) echolocation pulses emitted by an individual bat within a 5-s recording (Torrent et al. 2018; Yoh et al. 2022). We first split the recordings into 5-s WAV files, using Kaleidoscope v.5.3.8 software (Wildlife Acoustics, USA). We then filtered the recordings for a frequency range between 8 and 250 kHz and for pulses ranging from 2 to 500 milliseconds (López-Baucells et al. 2021). Files falling outside of these parameters were considered noise and removed from subsequent analysis. The software was configured to consider a maximum inter-syllable gap of 500 milliseconds, and a minimum of two pulses were required for detection.

Each bat pass was manually identified to either the species or genus level by analysing the following parameters of echolocation call: minimum and maximum pulse frequency, peak frequency, call duration, and pulse interval. Information on the parameters for the echolocation calls of each species was obtained from Rainho et al. (2010). Although we were able to identify Chaerephon pumilus in 84% of the 10,752 Chaerephon bat passes, we were not always able to distinguish between C. pumilus and C. tomensis due to overlap in the echolocation call parameters (Rainho et al. 2022). Accordingly, these two Chaerephon species were considered at the genus level.

We quantified bat activity for each species per night by summing the total number of bat passes recorded for each hour. To ensure data robustness, we included only species detected on at least 10% of the surveyed nights (Appel et al. 2021). Following the suggestion of Lashley et al. (2018), each species needed a minimum of 100 detections per land-use type to be considered in the subsequent analysis. Consequently, Taphozous mauritianus was excluded from the study due to its insufficient number of detections. Macronycteris thomensis was exclusively analysed within forests and shaded plantations. Hipposideros ruber, despite its limited presence with only 99 detections in forests, was included in the analysis as an exception for this specific habitat type. The species Myotis tricolor, although present on the island (Rainho et al. 2022), was not detected in this study.

Data analysis

Data analysis was based on circular statistics that required converting time data into a radian scale, spanning from zero hours (0) to 24 hours (2π). To examine both research questions, we estimated overlap coefficients that quantified (i) overlap between intraspecific activity between forest and human-altered land-use types, and (ii) overlap between interspecific species activity within the same land-use type.

The overlap coefficients (Δ), ranging from 0 to 1, quantify the extent of overlap in activity patterns between species/habitats. A value of 0 means the activity patterns are completely dissimilar, while a value of 1 indicates complete overlap. The confidence intervals with 95% certainty were estimated using the bootstrap technique with 9,999 resamples, following the methodology outlined by Ridout and Linkie (2009). For these calculations, we used the overlap package in R (Meredith et al. 2014). We followed Ridout and Linkie (2009) for the selection of the most appropriate overlap coefficient estimator. Ridout and Linkie (2009) considered three options: Dhat1 (Δ1), Dhat4 (Δ4), and Dhat5 (Δ5), each with distinct overlap measurement methods. Of these, Dhat1 emerged as well-suited for smaller sample sizes, while Dhat5 presented higher susceptibility to inconsistent results due to minor data variations making this estimator less suitable for robust outcomes. Factoring these considerations, we selected Dhat4 as our preferred estimator due to more consistent performance across sample sizes, particularly when exceeding 50 observations. To ascertain whether the two activity sets under comparison originated from identical distributions, we conducted a probability test using the compareCkern function from the activity R package (Rowcliffe et al. 2014).

To address our questions, we first employed Kernel density functions to visualise the data and subsequently calculated the overlap coefficient. Following Ridout and Linkie (2009) and Rivero-Monteagudo and Mena (2023), we used a smoothing parameter for Kernel density estimation (i.e., kmax) with a value of three. This value is known for robust estimates in both unimodal and bimodal activity distributions. We further applied an adjust factor of one for bandwidth scalar adjustment. These parameters interact to determine the width of the Kernel used for density estimation and later pattern display. Choosing appropriate values for kmax and adjust is crucial to accurately represent underlying patterns while avoiding undue influence from noise or over-smoothing (Rivero-Monteagudo and Mena 2023). These selections facilitated the use of the overlap estimator Δ4 for further analysis, treating the times of recording as part of a continuous circular distribution (Lashley et al. 2018).

Based on a total of 19,383 bat passes recorded, the most frequently detected species was the Chaerephon spp. (10,752 bat passes), followed by the endemic Miniopterus newtoni (7,900 bat passes), the endemic Macronycteris thomensis (632 bat passes), and Hipposideros ruber (99 bat passes). Forests and shaded plantations often harboured these three species, whereas only M. newtoni and Chaerephon spp. were found in any of the remaining altered land-use types (Table S2).

How did species-specific activity vary between forest and human-altered land-use types?

The activity of the endemic M. newtoni was generally characterised by two peaks, one at dusk and another at dawn (Fig. 2a-c), except in urban areas where activity was continuous during the night (Fig. 2d). As such, M. newtoni activity overlapped the least between forests and urban areas (0.62; 0.56–0.68). In all habitat comparisons, this species first peak of activity in forests started slightly earlier and the second peak ended slightly later (Fig. 2a-d).

The activity of Chaerephon spp. was also overall characterised by two peaks, between which nearly no activity of this species was detected (Fig. 2e-h). However, in contrast to M. newtoni, the habitats with the least overlap in the activity of Chaerephon spp. were forests and oil palm plantations (Fig. 2f). The activity overlap of Chaerephon spp. and M. newtoni in forests and the remaining human-altered land-use types was similar (Fig. 2e, g, h). Yet, compared to that of Chaerephon spp., the overlap in the activity between forests and human-altered land-use types was generally higher for M. newtoni.

The diel activity of the M. thomensis was characterised by a continuous period of activity throughout the night, in the middle of which we observed an activity peak (Fig. 2i). The activity of this species was very similar between forests and shaded plantations, as illustrated by the high coefficient overlap (0.86; 0.81–0.91) (Fig. 2i). For all the comparisons, the difference between activity distributions was significant (P < 0.01) (Fig. 2).

As for Hipposideros ruber, over two-thirds of the total 129 bat passes (ca. 77%) were recorded in forests, with the remaining occurring mostly in shaded and oil palm plantations (9% each) (Table S2), precluding comparisons in the activity of this species between land-use types. Notwithstanding, notably 39% (50/129) of this species bat passes occurred during the day (5:30 AM − 5:30 PM) (Fig. 3a), none of which were in humanised habitats.

How did the diel activity of different bat species overlap within the same land-use type?

Overlap in species activity within the same land-use type varied from 0.36 (0.33–0.39) in shaded plantations (Fig. 3b) to 0.59 (0.57–0.62) in the oil palm plantations (Fig. 3c). Species activity overlap was significantly lower in shaded plantations and forests—the two land-use types where all three species were present—intermediate in urban areas, and higher in oil palm plantations and agricultural areas (Fig. 3). The difference between activity distributions was significant in all comparisons (P < 0.001) (Fig. 3; Table S3).

Several studies have documented the negative impacts of habitat modification on island bats (e.g., Davies et al. 2016; Ferreira et al. 2022; Moseley et al. 2022). Here, we expand on these by showing that land-use change also leads to species-specific shifts in the diel activity of insular insectivorous bats and that assemblage-level temporal overlap varies significantly across different land-use types. We found that most species exhibited a bimodal activity pattern across the 24-hour period and that within-species differences in activity patterns between forest and agricultural/urban areas were more pronounced than those between forest and shaded plantations. This aligns with previous findings that between-habitat shifts in bat activity patterns are more pronounced in habitats with greater structural differences (Castro-Arellano et al. 2009; Montaño-Centellas et al. 2015; Presley et al. 2009a; Rocha et al. 2020). Moreover, overlap in the activity of different species was lower within less or not disturbed land-use types (forests and shaded plantations), where also more species were present.

Species-specific temporal overlap across land-use types

Human activities can significantly impact wildlife behaviour, leading some species to adjust their activity patterns in a habitat-specific manner, modulated by factors such as forest cover, prey availability, predation risk and competition (Adams and Thibault 2006). For both M. newtoni, and to a lesser extent Chaerephon spp., we found evidence of a substantial shift in activity patterns between forest habitats and urban spaces. Urbanised areas are especially impacted by artificial lighting and bats being (mostly) nocturnal can be especially sensitive to light pollution (Stone et al. 2015). Indeed, an increasing body of literature has reported light-induced behavioural shifts affecting the spatiotemporal activity patterns of bats (Russo et al. 2017; Voigt et al. 2021). Light-sensitive species tend to avoid illuminated areas, leaving these resources available for more light-tolerant species (Rowse et al. 2016). Our results seem to suggest that this might be the case for M. newtoni, which seems to be active for longer periods in urban areas, in relation to forested land-use types. However, an alternative justification for this pattern might relate to reduced prey availability in urban areas or to the activity patterns of arthropod prey. If prey is scarce or if it remains active and abundant throughout the night, it might be beneficial for M. newtoni to sustain a uniform level of activity throughout the night. As well as increasing foraging effectiveness, this relative constant activity throughout the night might serve to lower intraspecific competition in urban areas. Furthermore, given that urban areas are open habitats, M. newtoni might be disadvantaged when competing with Chaerephon spp., as molossids are particularly well adapted to forage in such open environments (Avila-Flores et al. 2023). This competition could further induce M. newtoni to forage in a more continuous manner throughout the night. Future research could focus on understanding this behaviour by surveying both arthropod and bat activity simultaneously. Regardless of the underlying causes for these patterns, the results for both species align with previous findings that urban environments pose unique challenges and opportunities for bats compared to natural forest settings (Jung and Threlfall 2016). In forested land-use types, M. newtoni was found to initiate its first peak of activity slightly earlier and to conclude its second peak slightly later than in other habitats. This aligns with the observations by Russo et al. (2007), who noted that bats in closed-canopy habitats tend to initiate activity earlier than those in open habitats. In São Tomé, and despite the absence of diurnal avian predators, this pattern seems to persist.

For Chaerephon spp., we observed a much lower activity in the first part of the night in oil palm plantations, comparing to forests. While this shift could initially suggest reduced prey availability in oil palm plantations due to changes in vegetation structure and arthropod abundance (Alonso-Rodríguez et al. 2017), it is important to consider molossids' resilience to human-induced habitat disturbance. Molossids, known as open space foragers (Russo and Ancillotto 2015), might not just be resilient but could potentially benefit from disturbance. Despite recording low numbers in forests, Chaerephon spp. were abundant in all habitats, albeit less so in oil palm plantations. This shift from forests to other habitats may indicate increased resource opportunities outside forested areas (Kusch et al. 2004). However, it's notable that activity levels were lower in oil palm plantations compared to other disturbance categories, suggesting potential differences in resource availability. To confirm this hypothesis, further assessment of feeding behaviour is warranted.

The activity patterns of M. thomensis in forests and shaded plantations exhibited a high overlap, indicating substantial similarity. This suggests that shaded plantations may provide an important habitat for M. thomensis, offering ecological conditions similar to re-growth forests. This echoes previous findings highlighting the sensitivity of Macronycteris spp. to forest change (e.g., Kemp et al. 2019) and emphasising the conservation potential of shaded plantations as complementary habitats for insectivorous bats (Wordley et al. 2017).

Assemblage-level temporal overlap across land-use types

The temporal activity patterns of insectivorous bats are recognised for their significant variability (Fenton et al. 1977; Rocha et al. 2020), influenced by factors like food availability, moonlight, cloud and canopy cover, and interspecific competition (Appel et al. 2019; Meyer et al. 2004; Rivero-Monteagudo and Mena, 2023; Vásquez et al. 2020). In this study, we observed variation in temporal overlap coefficients among different land-use types, indicating that species-specific changes in occurrence and activity patterns influence interspecific patterns of spatiotemporal overlap across the island.

Both oil palm plantations and agricultural areas exhibited the highest average coefficient of temporal overlap, followed by urban areas, shaded plantations, and forests. However, we also noted differences in the number of species present. Bat species may be able to coexist sympatrically, without the need for temporal partitioning, where species exhibit substantially different prey preferences (Gonçalves et al. 2024), or where the abundance of prey is sufficient to support similar prey preferences without substantial interspecific competition. Given differences in the morphology and echolocation between M. newtoni and Chaerephon spp. (Monadjem et al. 2010; Rainho et al. 2022), the temporal overlap coefficient we observe is likely due to differentiation in prey. However, M. newtoni is currently listed as Data Deficient by the IUCN Red List (Juste, 2019), so more research is needed to confirm dietary preferences of this species.

Moreover, high-altitude habitats generally support fewer arthropod species (Young, 2012). In São Tomé, forest habitats are currently largely limited to higher elevations and thus may experience lower insect abundance. This potential scarcity of prey may limit the interspecific temporal overlap to reduce foraging competition between co-occurring species (Delaval et al. 2005; Fern et al. 2018; Kronfeld-Schor and Dayan, 2003). Nonetheless, the observed lower coefficient overlaps in the more species-rich habitats of São Tomé support the notion that in environments with greater species diversity, time partitioning emerges as a strategy to alleviate competitive pressures (Adams and Thibault, 2006; Razgour et al. 2011).

Hipposideros ruber – a forest-restricted diurnal bat

Bats are predominantly nocturnal to mitigate interspecific competition and avoid predation by diurnal birds, as well as to prevent hyperthermy (Speakman 1995; Voigt and Lewanzik 2011). Forests provide shelter from heat and predators, allowing some bats to be active during the day. In São Tomé, where there are no diurnal avian predators (Chua and Aziz 2018; Russo et al. 2011), we observed an unusual amount of daytime activity among Hipposideros ruber (Russo et al. 2011; Rainho et al. 2022). This raises questions about how adaptable these bats are and how they use resources. Therefore, it is important to investigate whether this behaviour stems from unique ecological opportunities or a scarcity of nocturnal resources. Despite observing H. ruber bats exhibiting activity both day and night in forests without distinct peaks, their presence was minimal in other habitats such as shaded plantations with reduced tree cover. This indicates susceptibility to disturbance, rendering them vulnerable to land-use change.

Conservation implications

Our study sheds light on the impacts of land-use change on the diel activity patterns of insectivorous bats in the endemic-rich São Tomé Island. Although the altered diel activity patterns of bats in human-modified land-use types somehow support their ability to cope with some degree of land-use change, it also highlights that such changes affect bat behaviour. Given that the greatest changes in the diel activity patterns were in the most altered land-use types, our results emphasised that preserving forest habitats while promoting sustainable land-use practices are essential to maintain healthy bat assemblages. For instance, shaded plantations seem to comprise promising alternative habitats for maintaining at least part of the bat diversity in human-altered landscapes (Mendenhall et al. 2014). By integrating these measures into conservation efforts, we can enhance bat populations' resilience to land-use changes and maintain biodiversity across tropical insular systems.

Acknowledgements

ACF, ASF, PG, RR and AFP were supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 854248 (TROPIBIO). This programme further funded the fieldwork. We thank the Direction of Forests and Biodiversity of São Tomé and Príncipe for authorising the surveys. We thank BirdLife International São Tomé and Princípe Initiative, and Associação Monte Pico. We also thank all the landowners who allowed us to survey bats in their properties. VAM was funded by Fundação para Ciência e Tecnologia (FCT) through an individual research contract (2020.02547.CEECIND).

Author contributions

ACF conducted the data analysis and led the writing; ACF, ASF, PG and AFP collected the data; AFP and RR conceived the ideas which were improved by comments from all authors; all authors contributed with comments and revisions to drafts of the manuscript.

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No competing interests reported.

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Diel activity of insectivorous bats in response to land-use change in São Tomé Island, Gulf of Guinea

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Abstract

Figures

Introduction

Methods

Study area

Sampling design

Bioacoustics analysis

Data analysis

Results

How did species-specific activity vary between forest and human-altered land-use types?

How did the diel activity of different bat species overlap within the same land-use type?

Discussion

Species-specific temporal overlap across land-use types

Assemblage-level temporal overlap across land-use types

Conservation implications

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1