Papers by Paulo Bobrowiec
The distribution patterns of animal species at local scales have been explained by direct influen... more The distribution patterns of animal species at local scales have been explained by direct influences of vegetation structure, topography, food distribution, and availability. However, these variables can also interact and operate indirectly on the distribution of species. Here, we examined the direct and indirect effects of food availability (fruits and insects), vegetation clutter, and elevation in structuring phyl-lostomid bat assemblages in a continuous terra firme forest in Central Amazonia. Bats were captured in 49 plots over 25-km² of continuous forest. We captured 1138 bats belonging to 52 species with 7056 net*hours of effort. Terrain elevation was the strongest predictor of species and guild compositions, and of bat abundance. However, changes in elevation were associated with changes in vegetation clutter , and availability of fruits and insects consumed by bats, which are likely to have had direct effects on bat assemblages. Frugivorous bat composition was more influenced by availability of food-providing plants, while gleaning-animalivore composition was more influenced by the structural complexity of the vegetation. Although probably not causal, terrain elevation may be a reliable predictor of bat-assemblage structure at local scales in other regions. In situations where it is not possible to collect local variables, terrain elevation can substitute other variables, such as vegetation structure, and availability of fruits and insects. Abstract in Portuguese is available with online material.
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Biotropica, 2018
The distribution patterns of animal species at local scales have been explained by direct influen... more The distribution patterns of animal species at local scales have been explained by direct influences of vegetation structure, topography, food distribution, and availability. However, these variables can also interact and operate indirectly on the distribution of species. Here, we examined the direct and indirect effects of food availability (fruits and insects), vegetation clutter, and elevation in structuring phyl-lostomid bat assemblages in a continuous terra firme forest in Central Amazonia. Bats were captured in 49 plots over 25-km² of continuous forest. We captured 1138 bats belonging to 52 species with 7056 net*hours of effort. Terrain elevation was the strongest predictor of species and guild compositions, and of bat abundance. However, changes in elevation were associated with changes in vegetation clutter , and availability of fruits and insects consumed by bats, which are likely to have had direct effects on bat assemblages. Frugivorous bat composition was more influenced by availability of food-providing plants, while gleaning-animalivore composition was more influenced by the structural complexity of the vegetation. Although probably not causal, terrain elevation may be a reliable predictor of bat-assemblage structure at local scales in other regions. In situations where it is not possible to collect local variables, terrain elevation can substitute other variables, such as vegetation structure, and availability of fruits and insects. Abstract in Portuguese is available with online material.
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Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine... more Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest.We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours) and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.
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Lasiurus egregius (Peters, 1870) is a rare Neotropical vespertilionid bat and virtually no data o... more Lasiurus egregius (Peters, 1870) is a rare Neotropical vespertilionid bat and virtually no data on its ecology and echolocation calls are currently available. We report the capture of four individuals in the Central Amazon, representing the first record for the region and a significant (> 800 km) expansion of the species’ known range. Echolocation calls, recorded for the first time under natural conditions, were 1.5–8 ms in duration, and characterized by high mean bandwidth (18 kHz) and a mean frequency of maximum energy of 30 kHz. Lasiurus egregius (Peters, 1870) é um morcego vespertilionídeo Neotropical cuja ecologia é praticamente desconhecida. Nós reportamos a captura de 4 indivíduos na Amazônia Central, representando o primeiro registo para a região e uma ampliação significativa (> 800 km) da distribuição conhecida para a espécie. Os pulsos de ecolocalização, gravados pela primeira vez em condições naturais, tiveram 1.5–8 ms de duração e foram caracterizados por uma alta frequência modulada (18 kHz) e frequência de máxima energia média de 30 kHz.
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Morphological identification of prey fragments in vampire bat feces is impossible because of an e... more Morphological identification of prey fragments in vampire bat feces is impossible because of an exclusively
blood-based diet. Therefore, studies of their foraging ecology require innovative approaches. We investigated the
diet of Desmodus rotundus using a PCR–restriction fragment length polymorphism (RFLP) molecular method
by amplifying the cytochrome b mitochondrial gene (380 bp) from DNA fecal samples collected from captive
bats fed with blood from chickens, cattle, pigs, dogs, and humans—the 5 most frequently attacked prey species
in rural areas of the Brazilian Amazonia. The prey preference of the vampire bat was investigated in 18 riverine
villages, where the availability of domestic animals to bats was quantified. Prey DNA amplified from fecal
samples exhibited no visible signals of vampire bat DNA. A PCR–RFLP flowchart and a combination of 2 DNA
restriction enzymes allowed the direct identification of prey to species level. The enzymes’ restriction profile did
not overlap with those of vampire bats or wild mammal and avian species. Chickens were the most attacked prey
species (61.4% of the identifications, n = 27), but pigs were highly preferred in relation to prey availability. This
suggests a preference for mammalian blood in D. rotundus diet, with chickens exploited as a secondary food
source. No wild vertebrate species was identified in the fecal samples, indicating that vampire bats are selectively
feeding on the blood of domesticated animals, probably because they are more predictable and easily accessed
resources.
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Animal Conservation, Jan 1, 2010
The process of secondary succession on degraded lands in the Amazon depends on their land-use his... more The process of secondary succession on degraded lands in the Amazon depends on their land-use histories. In this scenario, little is known about how animal communities respond to different types of secondary vegetation in the region. We examined the effects of abandoned cattle pasture, Vismia- and Cecropia-dominated regrowth on the abundance of bat species and community composition in the Central Amazon, Brazil, based on 11 netting sites and on landscape characteristics. We captured 1444 bats, representing 26 species and two families (Phyllostomidae and Mormoopidae). Among the six most-captured Phyllostomidae bats, Sturnira lilium and Sturnira tildae had significantly higher capture rates in abandoned pasture, while Rhinophylla pumilio predominated in both Vismia- and Cecropia-dominated regrowth. An hybrid multidimensional scaling ordination revealed significant differences in the bat community among the three types of secondary vegetation. Phyllostominae bats were more common and richer in the less-disturbed areas of Cecropia-dominated regrowth, while Stenodermatinae species were more captured in abandoned pastures. Our results suggest that the type of secondary vegetation, together with its land-use history, affects bat community composition in the Central Amazon. The Phyllostominae subfamily (gleaning animalivores) was habitat selective and disappeared from areas experiencing constant disturbances. On the other hand, Stenodermatinae frugivorous bats often used and foraged in altered areas. We suggest that secondary vegetations in more-advanced successional stages can be used to augment the total area protected by forest conservation units.
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We tested the removal effect on nectar production in four bat-pollinated cerrado flowers. We comp... more We tested the removal effect on nectar production in four bat-pollinated cerrado flowers. We compared the amount of nectar after 7-12 removals with the accumulated nectar in non-manipulated flowers after 12 h. In all, but one species, removals increased volume by 1.5–4.6 times and sugar content by 1.6–4 times, which may affect flower visitation by bats, pollen flow, and reproduction.
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Papers by Paulo Bobrowiec
blood-based diet. Therefore, studies of their foraging ecology require innovative approaches. We investigated the
diet of Desmodus rotundus using a PCR–restriction fragment length polymorphism (RFLP) molecular method
by amplifying the cytochrome b mitochondrial gene (380 bp) from DNA fecal samples collected from captive
bats fed with blood from chickens, cattle, pigs, dogs, and humans—the 5 most frequently attacked prey species
in rural areas of the Brazilian Amazonia. The prey preference of the vampire bat was investigated in 18 riverine
villages, where the availability of domestic animals to bats was quantified. Prey DNA amplified from fecal
samples exhibited no visible signals of vampire bat DNA. A PCR–RFLP flowchart and a combination of 2 DNA
restriction enzymes allowed the direct identification of prey to species level. The enzymes’ restriction profile did
not overlap with those of vampire bats or wild mammal and avian species. Chickens were the most attacked prey
species (61.4% of the identifications, n = 27), but pigs were highly preferred in relation to prey availability. This
suggests a preference for mammalian blood in D. rotundus diet, with chickens exploited as a secondary food
source. No wild vertebrate species was identified in the fecal samples, indicating that vampire bats are selectively
feeding on the blood of domesticated animals, probably because they are more predictable and easily accessed
resources.
blood-based diet. Therefore, studies of their foraging ecology require innovative approaches. We investigated the
diet of Desmodus rotundus using a PCR–restriction fragment length polymorphism (RFLP) molecular method
by amplifying the cytochrome b mitochondrial gene (380 bp) from DNA fecal samples collected from captive
bats fed with blood from chickens, cattle, pigs, dogs, and humans—the 5 most frequently attacked prey species
in rural areas of the Brazilian Amazonia. The prey preference of the vampire bat was investigated in 18 riverine
villages, where the availability of domestic animals to bats was quantified. Prey DNA amplified from fecal
samples exhibited no visible signals of vampire bat DNA. A PCR–RFLP flowchart and a combination of 2 DNA
restriction enzymes allowed the direct identification of prey to species level. The enzymes’ restriction profile did
not overlap with those of vampire bats or wild mammal and avian species. Chickens were the most attacked prey
species (61.4% of the identifications, n = 27), but pigs were highly preferred in relation to prey availability. This
suggests a preference for mammalian blood in D. rotundus diet, with chickens exploited as a secondary food
source. No wild vertebrate species was identified in the fecal samples, indicating that vampire bats are selectively
feeding on the blood of domesticated animals, probably because they are more predictable and easily accessed
resources.