Effets de lisière sur les peuplements de chauves-souris frugivores et nectarivores de forêt primaire néotropicale en Guyane française

The impact of a road crossing a continuous Guyana primary forest was studied through the analysis of qualitative and quantitative changes in a frugivorous and nectarivorous bat community at different distances from forest edge. Bats were captured along three 3-km forest transects perpendicular to the edge, and at the Nouragues Station located 150 km in the interior of the primary forest block, in an uninhabited area. Along the 3-km transects, we caught over seven times more individuals than in primary forest, this value decreasing according to the distance from the edge. Moreover, at the very edge, species richness was higher than along transects, probably due to exchanges between primary forest and the open habitats. On the contrary, diversity values at forest edges were lower than in primary forest, with a demographic explosion of a few opportunistic phyllostomid species such as Carollia perspicillata and Artibeus jamaicensis. Species restricted to degraded habitat like Glossophaga soricina and Artibeus cinereus were still present 3 km away from the edge, where the proportion of C. perspicillata was seven times higher than in primary forest at Nouragues. These changes in the community of bats have important consequences on seed and pollen dispersal. So edge effects may signifi cantly affect both faunal and fl oral assemblage. We conclude that changes in bat community occur up to at least 3 km from forest edge, i. e. at a greater distance than that found for all other vertebrates previously studied. By their implications our results should be considered in habitat and species conservation management plansAfin d'étudier l'impact d'une route traversant une forêt primaire guyanaise continue, nous avons étudié les changements quantitatifs et qualitatifs du peuplement de chiroptères frugivores et nectarivores à différentes distances de la lisière. Les captures ont été effectuées le long de trois transects de 3 km chacun, partant de la lisière vers l'intérieur du bloc forestier ainsi qu'à la Station des Nouragues, située 150 km dans l'intérieur du bloc forestier, dans une zone intacte inhabitée. En lisière nous avons capturé sept fois plus d'individus qu'en forêt primaire, le nombre de captures diminuant au fur et à mesure que l'on s'éloigne de la lisière. De plus, les bordures révèlent une plus grande richesse spécifique que le long des transects, sans doute à cause de l'échange de chauves-souris entre forêt primaire et milieu ouvert. En revanche la diversité spécifique sur les 3 km de profondeur de lisière est plus faible qu'en forêt primaire témoin, avec une explosion démographique de quelques frugivores opportunistes comme Carollia perspicillata et Artibeus jamaicensis. A 3 km de la lisière, des espèces inféodées aux milieux ouverts comme Glossophaga soricina et Artiheus cinereus sont encore présentes, et la proportion de C. perspicillata y est sept fois plus grande qu'en forêt primaire des Nouragues. Ces changements dans la communauté de chiroptères ont des conséquences sur la pollinisation et sur la dispersion des graines. La lisière affecte donc les communautés animales et végétales. Nous concluons que les changements dans les communautés de chauves-souris ont lieu au moins jusqu'à 3 km des lisières, ce qui est plus important que ce qui avait été estimé jusqu'alors pour d'autres vertébrés. Ces résultats devraient être pris en compte par les gestionnaires de l'environnement et de la conservation des espèces

Compétition interspécifique et séparation des niches : l’exemple d’un peuplement de chauves-souris d’une forêt tropicale humide

Afin de comprendre l'organisation des communautés de chauves-souris ainsi que la coexistence de nombreuses espèces sympatriques, il est essentiel de déterminer comment les espèces utilisent et se partagent les ressources. Dans un premier temps, nous décrivons un peuplement de chauves-souris en forêt primaire de Guyane Française. Les facteurs locaux tels que la présence de gîtes particuliers comme les grottes, ou l'absence de perturbation anthropique ont une influence sur la structure et la composition des communautés. Au cours de cette étude, nous nous sommes concentrés sur les trois espèces les plus communes de chaque guilde végétarienne (frugivores de sous-bois, frugivores de canopée et nectarivores). Leur coexistence est possible grâce au partage des ressources alimentaires, de l'espace et/ou du temps. Au sein d'une même guilde, les plus petites espèces ont une bonne manoeuvrabilité et semblent occuper davantage les espaces fermés, moins attractifs pour leurs compétiteurs. Elles ont aussi un domaine vital plus petit que les grandes espèces. De même, le décalage des rythmes d'activités que nous avons observé, peut réduire la compétition entre les chauves-souris frugivores en diminuant les interférences directes lors de l'alimentation. En plus d'un intérêt pour l'écologie des communautés, cette étude décrivant des peuplements de chiroptères dans une forêt primaire intacte, peut servir de référence en biologie de conservation.To understand the organization of a bat community and the coexistence of sympatric species, it is essential to understand how species use and share common resources. First, we describe a bat community in a primary rainforest of French Guiana. The presence of particular roosting sites, such as caves, and the absence of disturbances are important local factors in structuring communities. In the course of this study, we focused on the three most common species of three vegetarian bat guilds (understorey frugivores, canopy frugivores and nectarivores). The local coexistence of these species is possible thanks to space, food and/or time partitioning. Space partitioning is consistent with the hypothesis that smaller bats with a more manoeuvrable flight tend to occupy more cluttered space less attractive to their competitors and have smaller home range. We observed a time partitioning that is likely to reduce competition among some frugivorous bat species by reducing direct interference during foraging. Besides an interest for the field community ecology, this study of a community living in a primary forest can be used as a reference for non disturbed habitat for conservation purposes

Impacts des perturbations d'origine anthropique sur les peuplements de chauves-souris en Guyane française

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-Museum-Bib zoologie mam. (751052312) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Edge effects on frugivorous and nectarivorous bat communities in a neotropical primary forest in French Guiana

The impact of a road crossing a continuous Guyana primary forest was studied through the analysis of qualitative and quantitative changes in a frugivorous and nectarivorous bat community at different distances from forest edge. Bats were captured along three 3-km forest transects perpendicular to the edge, and at the Nouragues Station located 150 km in the interior of the primary forest block, in an uninhabited area. Along the 3-km transects, we caught over seven times more individuals than in primary forest, this value decreasing according to the distance from the edge. Moreover, at the very edge, species richness was higher than along transects, probably due to exchanges between primary forest and the open habitats. On the contrary, diversity values at forest edges were lower than in primary forest, with a demographic explosion of a few opportunistic phyllostomid species such as Carollia perspicillata and Artibeus jamaicensis. Species restricted to degraded habitat like Glossophaga soricina and Artibeus cinereus were still present 3 km away from the edge, where the proportion of C. perspicillata was seven times higher than in primary forest at Nouragues. These changes in the community of bats have important consequences on seed and pollen dispersal. So edge effects may signifi cantly affect both faunal and fl oral assemblage. We conclude that changes in bat community occur up to at least 3 km from forest edge, i. e. at a greater distance than that found for all other vertebrates previously studied. By their implications our results should be considered in habitat and species conservation management plans.Effets de lisière sur les peuplements de chauves-souris frugivores et nectarivores de forêt primaire néotropicale en Guyane française. — Afin d’étudier l’impact d’une route traversant une forêt primaire guyanaise continue, nous avons étudié les changements quantitatifs et qualitatifs du peuplement de chiroptères frugivores et nectarivores à différentes distances de la lisière. Les captures ont été effectuées le long de trois transects de 3 km chacun, partant de la lisière vers l’intérieur du bloc forestier ainsi qu’à la Station des Nouragues, située 150 km dans l’intérieur du bloc forestier, dans une zone intacte inhabitée. En lisière nous avons capturé sept fois plus d’individus qu’en forêt primaire, le nombre de captures diminuant au fur et à mesure que l’on s’éloigne de la lisière. De plus, les bordures révèlent une plus grande richesse spécifique que le long des transects, sans doute à cause de l’échange de chauves-souris entre forêt primaire et milieu ouvert. En revanche la diversité spécifique sur les 3 km de profondeur de lisière est plus faible qu’en forêt primaire témoin, avec une explosion démographique de quelques frugivores opportunistes comme Carollia perspicillata et Artibeus jamaicensis. A 3 km de la lisière, des espèces inféodées aux milieux ouverts comme Glossophaga soricina et Artibeus cinereus sont encore présentes, et la proportion de C. perspicillata y est sept fois plus grande qu’en forêt primaire des Nouragues. Ces changements dans la communauté de chiroptères ont des conséquences sur la pollinisation et sur la dispersion des graines. La lisière affecte donc les communautés animales et végétales. Nous concluons que les changements dans les communautés de chauves-souris ont lieu au moins jusqu’à 3 km des lisières, ce qui est plus important que ce qui avait été estimé jusqu’alors pour d’autres vertébrés. Ces résultats devraient être pris en compte par les gestionnaires de l’environnement et de la conservation des espèces.Delaval Marguerite, Charles-dominique P. Edge effects on frugivorous and nectarivorous bat communities in a neotropical primary forest in French Guiana. In: Revue d'Écologie (La Terre et La Vie), tome 61, n°4, 2006. pp. 343-352

Interspecific competition and niche partitioning: example of a neotropical rainforest bat community

To understand the organization of a bat community and the coexistence of sympatric species, it is essential to understand how species use and share common resources. First, we describe a bat community in a primary rainforest of French Guiana. The presence of particular roosting sites, such as caves, and the absence of disturbances are important local factors in structuring communities. In the course of this study, we focused on the three most common species of three vegetarian bat guilds (understorey frugivores, canopy frugivores and nectarivores). The local coexistence of these species is possible thanks to space, food and/ or time partitioning. Space partitioning is consistent with the hypothesis that smaller bats with a more manoeuvrable flight tend to occupy more cluttered space less attractive to their competitors and have smaller home range. We observed a time partitioning that is likely to reduce competition among some frugivorous bat species by reducing direct interference during foraging. Besides an interest for the field community ecology, this study of a community living in a primary forest can be used as a reference for non disturbed habitat for conservation purposes.Compétition interspécifique et séparation des niches : l’exemple d’un peuplement de chauves-souris d’une forêt tropicale humide. — Afin de comprendre l’organisation des communautés de chauves-souris ainsi que la coexistence de nombreuses espèces sympatriques, il est essentiel de déterminer comment les espèces utilisent et se partagent les ressources. Dans un premier temps, nous décrivons un peuplement de chauves-souris en forêt primaire de Guyane Française. Les facteurs locaux tels que la présence de gîtes particuliers comme les grottes, ou l’absence de perturbation anthropique ont une influence sur la structure et la composition des communautés. Au cours de cette étude, nous nous sommes concentrés sur les trois espèces les plus communes de chaque guilde végétarienne (frugivores de sous-bois, frugivores de canopée et nectarivores). Leur coexistence est possible grâce au partage des ressources alimentaires, de l’espace et/ ou du temps. Au sein d’une même guilde, les plus petites espèces ont une bonne manoeuvrabilité et semblent occuper davantage les espaces fermés, moins attractifs pour leurs compétiteurs. Elles ont aussi un domaine vital plus petit que les grandes espèces. De même, le décalage des rythmes d’activités que nous avons observé, peut réduire la compétition entre les chauvessouris frugivores en diminuant les interférences directes lors de l’alimentation. En plus d’un intérêt pour l’écologie des communautés, cette étude décrivant des peuplements de chiroptères dans une forêt primaire intacte, peut servir de référence en biologie de conservation.Delaval Marguerite, Henry Mickaël, Charles-dominique P. Interspecific competition and niche partitioning: example of a neotropical rainforest bat community. In: Revue d'Écologie (La Terre et La Vie), tome 60, n°2, 2005. pp. 149-165

First record of Myotis albescens (Chiroptera, Vespertilionidae) in French Guiana

Myotis albescens occurs from Mexico southward to Uruguay and Argentina. The species is known for all South American countries except French Guiana and Chile. Based on one specimen recently collected in French Guiana we fill part of the gap in the distribution of the species in South America. Myotis albescens occurs in the Guiana Shield with other four congeners, from which it can be distinguished by external and skull traits. As an aid to future identifications, we provide a key to this assemblage

Cryptic Diversity in Common Mustached Bats Pteronotus cf. parnellii (Mormoopidae) in French Guiana and Brazilian Amapa

International audienceThe Common Mustached Bat (Pteronotus parnellii) is a mormoopid bat living in cavesin lowland rainforests throughout the north and eastern Neotropics, including severalCaribbean islands. Recent studies have shown that this taxon is certainly a composite ofseveral cryptic species, especially in the western part of the Guiana Shield, wheremolecular reconstructions and bioacoustics point to the presence of at least two crypticspecies that may not be related to genuine P. parnellii, native of Jamaica. The currenttaxonomy of this species complex is therefore confused. We examined here over 200bioacoustically identified individuals to show that two phonic types live in sympatry inFrench Guiana with no overlap in frequencies of echolocation calls. Morphologicvariation showed consistent and significant differences between the two phonic types,but external measurements were unable to discriminate all bats. Two mitochondrialmarkers analyzed in a selection of each of these phonic types were further used toevidence that they represent two genetically discrete groups, and to assign them to theexisting molecular clades described elsewhere. Molecular comparisons with referencespecimens sampled near the type localities of P. parnellii and P. rubiginosus furthersuggest that the 53 kHz phonic type found in French Guiana and Amapa (Brazil) shouldbe assigned to the later species, while the 59 kHz phonic type represents an undescribedspecies

Bioecological Drivers of Rabies Virus Circulation in a Neotropical Bat Community

International audienceIntroductionIn addition to the commonly accepted importance of the vampire bat in the maintenanceand transmission of the rabies virus (RABV) in South America, RABV infection of other speciesis widely evidenced, challenging their role in the viral cycle.Methodology / Principles findingsTo identify the bioecological drivers of RABV circulation in neotropical bat communities, weconducted a molecular and serological survey on almost 1,000 bats from 30 species, and a4-year longitudinal survey in two colonies of vampire bats in French Guiana. RABV wasmolecularly detected in a common vampire and in a frugivorous bat. The sequences correspondedto haematophagous bat-related strains and were close to viruses circulating in theBrazilian Amazon region. Species’ seroprevalence ranged from 0 to 20%, and the risk ofseropositivity was higher in bats with a haematophagous diet, living in monospecific coloniesand in dense forests. The longitudinal survey showed substantial temporal fluctuations,with individual waves of seroconversions and waning immunity. The high prevalencesobserved in bat communities, in most habitats and in species that do not share the samemicrohabitats and bioecological patterns, the temporal variations, and a rather short periodof detectable antibodies as observed in recaptured vampires suggest (i) frequent exposureof animals, (ii) an ability of the infected host to control and eliminate the virus, (iii) morerelaxed modes of exposure between bats than the commonly assumed infection via directcontact with saliva of infected animals, all of which should be further investigated.Conclusions / significanceWe hypothesize that RABV circulation in French Guiana is mainly maintained in the pristineforest habitats that may provide sufficient food resources to allow vampire bats, the mainprevalent species, to survive and RABV to be propagated. However, on the forest edge and in disturbed areas, human activities may induce more insidious effects such as defaunation.One of the ecological consequences is the disappearance of resources for tertiary or secondaryconsumers. Populations of vampires may then shift to alternative resources such ascattle, domestic animals and humans. Therefore, a good forest status, allowing both a dilutioneffect in highly rich bat communities and the maintenance of large populations ofmedium-sized and large mammals used as prey by vampires, should prevent their migrationto anthropized areas

How Social Structure Drives the Population Dynamics of the Common Vampire Bat (Desmodus rotundus, Phyllostomidae)

International audienceSocial systems are major drivers of population structure and gene flow, with important effects on dynamics and dispersal of associated populations of parasites. Among bats, the common vampire bat (Desmodus rotundus) has likely one of the most complex social structures. Using autosomal and mitochondrial markers on vampires from Mexico, French Guiana, and North Brazil, from both roosting and foraging areas, we observed an isolation by distance at the wider scale and lower but significant differentiation between closer populations (<50 km). All populations had a low level of relatedness and showed deviations from Hardy-Weinberg equilibrium and a low but significant inbreeding coefficient. The associated heterozygote deficiency was likely related to a Wahlund effect and to cryptic structures, reflecting social groups living in syntopy, both in roosting and foraging areas, with only limited admixture. Discrepancy between mitochondrial and nuclear markers suggests female philopatry and higher dispersal rates in males, associated with peripheral positions in the groups. Vampires are also the main neotropical reservoir for rabies virus, one of the main lethal pathogens for humans. Female social behaviors and trophallaxis may favor a rapid spread of virus to related and unrelated offspring and females. The high dispersal capacity of males may explain the wider circulation of viruses and the inefficacy of bat population controls. In such opportunistic species, gene connectivity should be considered for management decision making. Strategies such as culling could induce immigration of bats from neighboring colonies to fill vacant roosts and feeding areas, associated with the dispersal of viral strains