Linking colony size with quantitative estimates of ecosystem services of African fruit bats

Toor, Mariëlle Liduine van; O’Mara, M. Teague; Abedi-Lartey, Michael; Wikelski, Martin; Fahr, Jakob; Dechmann, Dina K. N.

doi:10.1016/j.cub.2019.02.033

Cited by 31 publications

(45 citation statements)

References 10 publications

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“…Despite innovations in direct (Forget and Milleron 1991, Reiter et al 2006, Hirsch et al 2012) and indirect seed tracking methods (Godoy and Jordano 2001, Jordano et al 2007, Carlo et al 2009), it is often prohibitively burdensome to assess post-removal seed fates. One tractable way to assess seed dispersal quality in terms of dispersal distance is to use frugivore movement data paired with ecologically relevant information on fruit preferences and seed passage/ handling times (e.g., Westcott et al 2005, Kays et al 2011, Karubian et al 2012, Abedi-Lartey et al 2016, Rehm et al 2019, van Toor et al 2019. Because dispersal distance depends on animal behavior and physiology (Russo et al 2006, Morales et al 2013) and fruit secondary compounds can influence both of these aspects, a logical hypothesis is that fruit secondary compounds may play an important role in determining variation in dispersal distance within and among plant species.…”

Section: Introductionmentioning

confidence: 99%

Defensive fruit metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales

Baldwin

Dechmann

Thies

et al. 2020

Ecology

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metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales. Ecology 101(2):Abstract. The paradoxical presence of toxic chemical compounds in ripe fruits represents a balance between plant enemies and allies: chemical traits can defend seeds against antagonistic herbivores, seed predators, or fungal pathogens, but also can impose costs by repelling mutualistic seed dispersers, although the costs are often difficult to quantify. Seeds gain fitness benefits from traveling far from the parent plant, as they can escape from parental competition and elude specialized herbivores as well as pathogens that accumulate on adult plants. However, seeds are difficult to follow from their parent plant to their final destination. Thus, little is known about the factors that determine seed dispersal distance. We investigated this potential cost of fruit secondary compounds, reduced seed dispersal distance, by combining two data sets from previous work on a Neotropical bat-plant dispersal system (bats in the genus Carollia and plants in the genus Piper). We used data from captive behavioral experiments, which show how amides in ripe fruits of Piper decrease the retention time of seeds and alter food choices.With new analyses, we show that these defensive secondary compounds also delay the time of fruit removal. Next, with a behaviorally annotated bat telemetry data set, we quantified postfeeding movements (i.e., seed dispersal distances). Using generalized additive mixed models we found that seed dispersal distances varied nonlinearly with gut retention times as well as with the time of fruit removal. By interrogating the model predictions, we identified two novel mechanisms by which fruit secondary compounds can impose costs in terms of decreased seed dispersal distances: (1) small-scale reductions in gut retention time and (2) causing fruits to forgo advantageous bat activity peaks that confer high seed dispersal distances.

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Section: Introductionmentioning

confidence: 99%

Defensive fruit metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales

Baldwin

Dechmann

Thies

et al. 2020

Ecology

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“…Fruit bats use constant flapping flight and rarely glide or soar (Harris et al, 1990;Lindhe Norberg and Norberg, 2012). During their commuting flights of up to 90 km from a central roost (Sapir et al, 2014;Fahr et al, 2015;Abedi-Lartey et al, 2016;van Toor et al, 2019), they decrease airspeed with wind support, and increase airspeed with crosswinds (Sapir et al, 2014). We hypothesize that if ODBA reflects relative energetic expenditure or power output in bats, then we will find a curvilinear relationship between ODBA and airspeed similar to the theoretical total power requirements of flight (Usherwood et al, 2011;Spivey and Bishop, 2013).…”

Section: Introductionmentioning

confidence: 73%

Overall Dynamic Body Acceleration in Straw-Colored Fruit Bats Increases in Headwinds but Not With Airspeed

et al. 2019

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Atmospheric conditions impact how animals use the aerosphere, and birds and bats should modify their flight to minimize energetic expenditure relative to changing wind conditions. To investigate how free-ranging straw-colored fruit bats (Eidolon helvum) fly with changing wind support, we use data collected from bats fit with GPS loggers and an integrated triaxial accelerometer and measure flight speeds, wingbeat frequency, and overall dynamic body acceleration (ODBA) as an estimate for energetic expenditure. We predicted that if ODBA reflects energetic expenditure, then we should find a curvilinear relationship between ODBA and airspeed consistent with aerodynamic theory. We expected that bats would lower their airspeed with tailwind support and that ODBA will decrease with increasing tailwinds and increase with wingbeat frequency. We found that wingbeat frequency has the strongest positive relationship with ODBA. There was a small, but negative, relationship between airspeed and ODBA, and bats decreased ODBA with increasing tailwind. Bats flew at ground speeds of 9.6 ± 2.4 ms −1 (Mean ± SD, range: 4.3-23.9 ms −1) and airspeeds of 10.2 ± 2.5 ms −1 , and did not modify their wingbeat frequency with speed. Free-ranging straw-colored fruit bats therefore exerted more total ODBA in headwinds but not when they changed their airspeed. It is possible that the flexibility in wingbeat kinematics may make flight of free-ranging bats less costly than currently predicted or alternatively that the combination of ODBA and airspeed at our scales of measurement does not reflect this relationship in straw-colored fruit bats. Further work is needed to understand the full potential of free-ranging bat flight and how well bio-logging techniques reflect the costs of bat flight.

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“…Data were retrieved using a base station connected to a directional high-gain antenna. Further details on field procedures and the tracking devices can be found in earlier studies that used data from the same bats [25,26,31,37,40].…”

Section: Bat Capture and Trackingmentioning

confidence: 99%

“…It feeds upon a large variety of fruits and flowers, often moving tens of kilometres between the roost and the foraging areas on a daily basis [25]. These features contribute to making this species a keystone seed disperser in Africa, and critical for maintaining vegetation dynamics in fragmented tropical forests [26]. Despite its high ecological relevance, populations of straw-coloured fruit bat are declining across its range, with hunting probably being the main cause [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Assessing roost disturbance of straw-coloured fruit bats (Eidolon helvum) through tri-axial acceleration

et al. 2020

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The disturbance of wildlife by humans is a worldwide phenomenon that contributes to the loss of biodiversity. It can impact animals’ behaviour and physiology, and this can lead to changes in species distribution and richness. Wildlife disturbance has mostly been assessed through direct observation. However, advances in bio-logging provide a new range of sensors that may allow measuring disturbance of animals with high precision and remotely, and reducing the effects of human observers. We used tri-axial accelerometers to identify daytime flights of roosting straw-coloured fruit bats (Eidolon helvum), which were used as a proxy for roost disturbance. This bat species roosts on trees in large numbers (often reaching hundreds of thousands of animals), making them highly vulnerable to disturbance. We captured and tagged 46 straw-coloured fruit bats with dataloggers, containing a global positioning system (GPS) and an accelerometer, in five roosts in Ghana, Burkina Faso and Zambia. Daytime roost flights were identified from accelerometer signatures and modelled against our activity in the roosts during the days of trapping, as a predictor of roost disturbance, and natural stressors (solar irradiance, precipitation and wind speed). We found that daytime roost flight probability increased during days of trapping and with increasing solar irradiance (which may reflect the search for shade to prevent overheating). Our results validate the use of accelerometers to measure roost disturbance of straw-coloured fruit bats and suggest that these devices may be very useful in conservation monitoring programs for large fruit bat species.

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Linking colony size with quantitative estimates of ecosystem services of African fruit bats

Cited by 31 publications

References 10 publications

Defensive fruit metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales

Defensive fruit metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales

Overall Dynamic Body Acceleration in Straw-Colored Fruit Bats Increases in Headwinds but Not With Airspeed

Assessing roost disturbance of straw-coloured fruit bats (Eidolon helvum) through tri-axial acceleration

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