Benoît de Thoisy | Institut Pasteur de la Guyane (original) (raw)
Papers by Benoît de Thoisy
Virus Research, 2006
Mayaro (MAY) virus is a member of the genus Alphavirus in the family Togaviridae. Alphaviruses ar... more Mayaro (MAY) virus is a member of the genus Alphavirus in the family Togaviridae. Alphaviruses are distributed throughout the world and cause a wide range of diseases in humans and animals. Here, we determined the complete nucleotide sequence of MAY from a viral strain isolated from a French Guianese patient. The deduced MAY genome was 11,429 nucleotides in length, excluding the 5 cap nucleotide and 3 poly(A) tail. Nucleotide and amino acid homologies, as well as phylogenetic analyses of the obtained sequence confirmed that MAY is not a recombinant virus and belongs to the Semliki Forest complex according to the antigenic complex classification. Furthermore, analyses based on the E1 region revealed that MAY is closely related to Una virus, the only other South American virus clustering with the Old World viruses. On the basis of our results and of the alphaviruses diversity and pathogenicity, we suggest that alphaviruses may have an Old World origin.
Statistical and spatial analyses of both historical time series and remotely sensed data show a l... more Statistical and spatial analyses of both historical time series and remotely sensed data show a link between the spatial distribution and growth of gold production across the Guiana Shield in northeast Amazonia. Results indicate that an exponential rise in production across an expanding area is primarily a delayed response to the 1971À1978 market flotation of international gold prices. The subsequent 10-fold (2-fold) average nominal (real) price increase has provided a compelling economic incentive to mass exploitation of lower-grade gold deposits. The ground-based and remotely sensed distributions of mining activity are strongly attached to these deposits that dominate the region's gold geology. The presence of these gold-bearing formations in conservation and sustainable timber zones has sparked social conflict and environmental degradation across the region. Left unmanaged, more than a quarter-million squarekilometer area of tropical forest zoned for protection and sustainable management could ultimately be compromised by the price-driven boom in gold mining through poorly integrated resource use planning, lack of reclamation effort, and control of illegal operations. Serious public health issues propagated through the unregulated mining environment further erode the financial benefits achieved through gold extraction. This study demonstrates in part how international economic policies successfully stabilizing more conspicuous centers of the global economy can have unintended but profound environmental and social impacts on remote commodity frontiers.
Journal of Animal Ecology, 2012
1. The assessment of species extinction risk has been well established for some time now. Assessi... more 1. The assessment of species extinction risk has been well established for some time now. Assessing the potential for recovery in endangered species is however much more challenging, because complementary approaches are required to detect reliable signals of positive trends. 2. This study combines genetics, demography and behavioural data at three different time-scales to assess historical and recent population changes and evidence of reproductive synchrony in a small population of olive ridley sea turtle Lepidochelys olivacea. Lepidochelys is considered as the most extraordinary example of reproductive synchrony in reptiles, yet to date, it has only been reported in large populations. 3. Using Bayesian coalescent-based models on microsatellite nuclear DNA variability, we demonstrate that effective population size in olive ridleys nesting in French Guiana has dramatically declined by 99% over the last 20 centuries. This low current population size is further illustrated by the absence of genetic mitochondrial DNA diversity in the present nesting population. Yet, monitoring of nesting sites in French Guiana suggests a possible recovery of the population over the last decade. 4. Satellite telemetry shows that over the first 14 days of their 28-days inter-nesting interval, i.e. when eggs maturation is likely to occur, gravid females disperse over the continental shelf. They then gather together with a striking spatiotemporal consistency close to the nesting site, where they later emerge for their second nesting event. 5. Our results therefore suggest that reproductive synchrony also occurs in small populations. Olive ridleys may ensure this synchrony by adjusting the duration of the second half of their internesting interval prior to landing, possibly through social mediation. 6. Such reproductive synchrony may be related to the maintenance of some species-specific strategy despite former collapse and may contribute to the present population recovery. The gregarious behaviour of reproductive individuals close to shore where human-induced perturbations occur is however a cause for conservation concern for this still poorly known species.
Journal of Experimental Marine Biology and Ecology, 2008
The Atlantic Ocean hosts a major part of the world's leatherback population, with the largest roo... more The Atlantic Ocean hosts a major part of the world's leatherback population, with the largest rookeries being located in the northern part of South America (Suriname/French Guiana) and in western Central Africa (Gabon). In contrast with the dramatic decline of nesting populations in the Pacific Ocean, some Atlantic leatherback rookeries have recently been reported to be stable or even to increase. This raises the question, which particular research and conservation initiatives, past and present, may have led to such development. Here we present an overview of the historical and present research and conservation efforts in French Guiana, Suriname and Gabon and highlight current gaps in knowledge and required improvements to maintain protection for the major rookeries of this critically endangered species.
Oryx, 2009
The estimated number of olive ridley marine turtles Lepidochelys olivacea nesting annually in
Animal Conservation, 2006
Because of logistical and financial constraints, nest counts of marine turtles are often limited ... more Because of logistical and financial constraints, nest counts of marine turtles are often limited in time and space. To overcome this difficulty, we developed a numerical model that fits the seasonal pattern of marine turtles nesting from complete or fragmented datasets. The duration of the main nesting season, the position and amplitude of its maximum as well as the residual number of nests, outside of the main season are obtained numerically by a least square adjustment. For the seven complete time series at our disposal (Dermochelys coriacea and Lepidochelys olivacea turtles, coast of French Guiana), the model reproduces the seasonal pattern with a correlation of rZ0.97. When applied on a fragmented dataset, the model accuracy depends on the duration and on the temporal distribution of the monitoring (effort equally distributed during the entire season or concentrated on a part of it only). As a result of this study, we clearly advocate a strategy of monitoring distributed all over the nesting season. Following this recommendation, the model estimates the annual number of nests with a median error lower than 10% when considering only 50 days of monitoring.
Biological Conservation, 2015
ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red... more ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red List since 1986. This species is especially threatened in South America due to bycatch by fisheries along the northeastern coasts. It is particularly crucial to identify specific marine areas for conservation measures to safeguard green turtle rookeries in Suriname and French Guiana. Our study provides valuable information to attain this goal, describing the satellite tracking of post-nesting migration routes used by 16 green turtles fitted with Argos/GPS Fastloc satellite tags at the end of the nesting season. The data we obtained show a single migratory corridor: all the turtles followed a similar eastward route along the Guianan and the Brazilian coast. The GPS signal was lost for two individuals a few weeks after tracking commenced, suggesting that they were caught by fishermen. Thirteen turtles reached the coast of the state of Ceará (Brazil), where they spent at least one month. One turtle continued 700 km further to the coastal regions of Natal and Recife (Brazil), which are known feeding areas of the green turtle populations nesting on Ascension Island. The migratory corridor is essentially narrow, with a width of 22 km for most of the distance covered. It constitutes a major dynamic link between the nesting and feeding areas and crosses three Regional Management Units of the Atlantic basin. Since green turtles face a high risk of being caught in fishing nets, measures of protection should be implemented along this corridor.
Chelonian Conservation and Biology, 2007
The estimated number of olive ridley marine turtles Lepidochelys olivacea nesting annually in
Mitochondrial DNA, Jan 18, 2015
The green turtle Chelonia mydas undertakes wide-ranging migrations between feeding and nesting si... more The green turtle Chelonia mydas undertakes wide-ranging migrations between feeding and nesting sites, resulting in mixing and isolation of genetic stocks. We used mtDNA control region to characterize the genetic composition, population structure, and natal origins of C. mydas in the West Atlantic Ocean, at one feeding ground (State of Rio de Janeiro, Brazil), and three Caribbean nesting grounds (French Guiana, Guadeloupe, and Suriname). The feeding ground presented considerable frequency of common haplotypes from the South Atlantic, whereas the nesting sites presented a major contribution of the most common haplotype from the Caribbean. MSA revealed multiple origins of individuals at the feeding ground, notably from Ascension Island, Guinea Bissau, and French Guiana. This study enables a better understanding of the dispersion patterns and highlights the importance of connecting both nesting and feeding areas. Effective conservation initiatives need to encompass these ecologically an...
PLOS ONE, 2015
In response to seasonality and spatial segregation of resources, sea turtles undertake long journ... more In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration.
Biological Conservation, 2015
ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red... more ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red List since 1986. This species is especially threatened in South America due to bycatch by fisheries along the northeastern coasts. It is particularly crucial to identify specific marine areas for conservation measures to safeguard green turtle rookeries in Suriname and French Guiana. Our study provides valuable information to attain this goal, describing the satellite tracking of post-nesting migration routes used by 16 green turtles fitted with Argos/GPS Fastloc satellite tags at the end of the nesting season. The data we obtained show a single migratory corridor: all the turtles followed a similar eastward route along the Guianan and the Brazilian coast. The GPS signal was lost for two individuals a few weeks after tracking commenced, suggesting that they were caught by fishermen. Thirteen turtles reached the coast of the state of Ceará (Brazil), where they spent at least one month. One turtle continued 700 km further to the coastal regions of Natal and Recife (Brazil), which are known feeding areas of the green turtle populations nesting on Ascension Island. The migratory corridor is essentially narrow, with a width of 22 km for most of the distance covered. It constitutes a major dynamic link between the nesting and feeding areas and crosses three Regional Management Units of the Atlantic basin. Since green turtles face a high risk of being caught in fishing nets, measures of protection should be implemented along this corridor.
PLoS ONE, 2013
The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in ... more The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic diversity and species history.
The crab-eating fox Cerdocyon thous is a neotropical canid occurring in northwestern and southern... more The crab-eating fox Cerdocyon thous is a neotropical canid occurring in northwestern and southern South America. Here we report the first records of the species in the Cabo Orange National Park, Amapá state, north Brazil. These records from the eastern part of the Guiana Shield suggest a northward extension of the core southern distribution.
Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escri... more Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escrita del editor. Copyright © 2010 Fundación Universitaria San Martín Derechos reservados conforme a la ley Primera edición Bogotá, Colombia ISBN libro impreso 978-958-721-020-0 ISBEN libro versión digital 978-958-721-021-7 Impresión Gráficas San Martín
Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escri... more Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escrita del editor. Copyright © 2010 Fundación Universitaria San Martín Derechos reservados conforme a la ley Primera edición Bogotá, Colombia ISBN libro impreso 978-958-721-020-0 ISBN libro versión digital 978-958-721-021-7 Impresión Gráficas San Martín
Virus Research, 2006
Mayaro (MAY) virus is a member of the genus Alphavirus in the family Togaviridae. Alphaviruses ar... more Mayaro (MAY) virus is a member of the genus Alphavirus in the family Togaviridae. Alphaviruses are distributed throughout the world and cause a wide range of diseases in humans and animals. Here, we determined the complete nucleotide sequence of MAY from a viral strain isolated from a French Guianese patient. The deduced MAY genome was 11,429 nucleotides in length, excluding the 5 cap nucleotide and 3 poly(A) tail. Nucleotide and amino acid homologies, as well as phylogenetic analyses of the obtained sequence confirmed that MAY is not a recombinant virus and belongs to the Semliki Forest complex according to the antigenic complex classification. Furthermore, analyses based on the E1 region revealed that MAY is closely related to Una virus, the only other South American virus clustering with the Old World viruses. On the basis of our results and of the alphaviruses diversity and pathogenicity, we suggest that alphaviruses may have an Old World origin.
Statistical and spatial analyses of both historical time series and remotely sensed data show a l... more Statistical and spatial analyses of both historical time series and remotely sensed data show a link between the spatial distribution and growth of gold production across the Guiana Shield in northeast Amazonia. Results indicate that an exponential rise in production across an expanding area is primarily a delayed response to the 1971À1978 market flotation of international gold prices. The subsequent 10-fold (2-fold) average nominal (real) price increase has provided a compelling economic incentive to mass exploitation of lower-grade gold deposits. The ground-based and remotely sensed distributions of mining activity are strongly attached to these deposits that dominate the region's gold geology. The presence of these gold-bearing formations in conservation and sustainable timber zones has sparked social conflict and environmental degradation across the region. Left unmanaged, more than a quarter-million squarekilometer area of tropical forest zoned for protection and sustainable management could ultimately be compromised by the price-driven boom in gold mining through poorly integrated resource use planning, lack of reclamation effort, and control of illegal operations. Serious public health issues propagated through the unregulated mining environment further erode the financial benefits achieved through gold extraction. This study demonstrates in part how international economic policies successfully stabilizing more conspicuous centers of the global economy can have unintended but profound environmental and social impacts on remote commodity frontiers.
Journal of Animal Ecology, 2012
1. The assessment of species extinction risk has been well established for some time now. Assessi... more 1. The assessment of species extinction risk has been well established for some time now. Assessing the potential for recovery in endangered species is however much more challenging, because complementary approaches are required to detect reliable signals of positive trends. 2. This study combines genetics, demography and behavioural data at three different time-scales to assess historical and recent population changes and evidence of reproductive synchrony in a small population of olive ridley sea turtle Lepidochelys olivacea. Lepidochelys is considered as the most extraordinary example of reproductive synchrony in reptiles, yet to date, it has only been reported in large populations. 3. Using Bayesian coalescent-based models on microsatellite nuclear DNA variability, we demonstrate that effective population size in olive ridleys nesting in French Guiana has dramatically declined by 99% over the last 20 centuries. This low current population size is further illustrated by the absence of genetic mitochondrial DNA diversity in the present nesting population. Yet, monitoring of nesting sites in French Guiana suggests a possible recovery of the population over the last decade. 4. Satellite telemetry shows that over the first 14 days of their 28-days inter-nesting interval, i.e. when eggs maturation is likely to occur, gravid females disperse over the continental shelf. They then gather together with a striking spatiotemporal consistency close to the nesting site, where they later emerge for their second nesting event. 5. Our results therefore suggest that reproductive synchrony also occurs in small populations. Olive ridleys may ensure this synchrony by adjusting the duration of the second half of their internesting interval prior to landing, possibly through social mediation. 6. Such reproductive synchrony may be related to the maintenance of some species-specific strategy despite former collapse and may contribute to the present population recovery. The gregarious behaviour of reproductive individuals close to shore where human-induced perturbations occur is however a cause for conservation concern for this still poorly known species.
Journal of Experimental Marine Biology and Ecology, 2008
The Atlantic Ocean hosts a major part of the world's leatherback population, with the largest roo... more The Atlantic Ocean hosts a major part of the world's leatherback population, with the largest rookeries being located in the northern part of South America (Suriname/French Guiana) and in western Central Africa (Gabon). In contrast with the dramatic decline of nesting populations in the Pacific Ocean, some Atlantic leatherback rookeries have recently been reported to be stable or even to increase. This raises the question, which particular research and conservation initiatives, past and present, may have led to such development. Here we present an overview of the historical and present research and conservation efforts in French Guiana, Suriname and Gabon and highlight current gaps in knowledge and required improvements to maintain protection for the major rookeries of this critically endangered species.
Oryx, 2009
The estimated number of olive ridley marine turtles Lepidochelys olivacea nesting annually in
Animal Conservation, 2006
Because of logistical and financial constraints, nest counts of marine turtles are often limited ... more Because of logistical and financial constraints, nest counts of marine turtles are often limited in time and space. To overcome this difficulty, we developed a numerical model that fits the seasonal pattern of marine turtles nesting from complete or fragmented datasets. The duration of the main nesting season, the position and amplitude of its maximum as well as the residual number of nests, outside of the main season are obtained numerically by a least square adjustment. For the seven complete time series at our disposal (Dermochelys coriacea and Lepidochelys olivacea turtles, coast of French Guiana), the model reproduces the seasonal pattern with a correlation of rZ0.97. When applied on a fragmented dataset, the model accuracy depends on the duration and on the temporal distribution of the monitoring (effort equally distributed during the entire season or concentrated on a part of it only). As a result of this study, we clearly advocate a strategy of monitoring distributed all over the nesting season. Following this recommendation, the model estimates the annual number of nests with a median error lower than 10% when considering only 50 days of monitoring.
Biological Conservation, 2015
ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red... more ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red List since 1986. This species is especially threatened in South America due to bycatch by fisheries along the northeastern coasts. It is particularly crucial to identify specific marine areas for conservation measures to safeguard green turtle rookeries in Suriname and French Guiana. Our study provides valuable information to attain this goal, describing the satellite tracking of post-nesting migration routes used by 16 green turtles fitted with Argos/GPS Fastloc satellite tags at the end of the nesting season. The data we obtained show a single migratory corridor: all the turtles followed a similar eastward route along the Guianan and the Brazilian coast. The GPS signal was lost for two individuals a few weeks after tracking commenced, suggesting that they were caught by fishermen. Thirteen turtles reached the coast of the state of Ceará (Brazil), where they spent at least one month. One turtle continued 700 km further to the coastal regions of Natal and Recife (Brazil), which are known feeding areas of the green turtle populations nesting on Ascension Island. The migratory corridor is essentially narrow, with a width of 22 km for most of the distance covered. It constitutes a major dynamic link between the nesting and feeding areas and crosses three Regional Management Units of the Atlantic basin. Since green turtles face a high risk of being caught in fishing nets, measures of protection should be implemented along this corridor.
Chelonian Conservation and Biology, 2007
The estimated number of olive ridley marine turtles Lepidochelys olivacea nesting annually in
Mitochondrial DNA, Jan 18, 2015
The green turtle Chelonia mydas undertakes wide-ranging migrations between feeding and nesting si... more The green turtle Chelonia mydas undertakes wide-ranging migrations between feeding and nesting sites, resulting in mixing and isolation of genetic stocks. We used mtDNA control region to characterize the genetic composition, population structure, and natal origins of C. mydas in the West Atlantic Ocean, at one feeding ground (State of Rio de Janeiro, Brazil), and three Caribbean nesting grounds (French Guiana, Guadeloupe, and Suriname). The feeding ground presented considerable frequency of common haplotypes from the South Atlantic, whereas the nesting sites presented a major contribution of the most common haplotype from the Caribbean. MSA revealed multiple origins of individuals at the feeding ground, notably from Ascension Island, Guinea Bissau, and French Guiana. This study enables a better understanding of the dispersion patterns and highlights the importance of connecting both nesting and feeding areas. Effective conservation initiatives need to encompass these ecologically an...
PLOS ONE, 2015
In response to seasonality and spatial segregation of resources, sea turtles undertake long journ... more In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration.
Biological Conservation, 2015
ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red... more ABSTRACT The green turtle (Chelonia mydas) is classified as an endangered species on the IUCN Red List since 1986. This species is especially threatened in South America due to bycatch by fisheries along the northeastern coasts. It is particularly crucial to identify specific marine areas for conservation measures to safeguard green turtle rookeries in Suriname and French Guiana. Our study provides valuable information to attain this goal, describing the satellite tracking of post-nesting migration routes used by 16 green turtles fitted with Argos/GPS Fastloc satellite tags at the end of the nesting season. The data we obtained show a single migratory corridor: all the turtles followed a similar eastward route along the Guianan and the Brazilian coast. The GPS signal was lost for two individuals a few weeks after tracking commenced, suggesting that they were caught by fishermen. Thirteen turtles reached the coast of the state of Ceará (Brazil), where they spent at least one month. One turtle continued 700 km further to the coastal regions of Natal and Recife (Brazil), which are known feeding areas of the green turtle populations nesting on Ascension Island. The migratory corridor is essentially narrow, with a width of 22 km for most of the distance covered. It constitutes a major dynamic link between the nesting and feeding areas and crosses three Regional Management Units of the Atlantic basin. Since green turtles face a high risk of being caught in fishing nets, measures of protection should be implemented along this corridor.
PLoS ONE, 2013
The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in ... more The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic diversity and species history.
The crab-eating fox Cerdocyon thous is a neotropical canid occurring in northwestern and southern... more The crab-eating fox Cerdocyon thous is a neotropical canid occurring in northwestern and southern South America. Here we report the first records of the species in the Cabo Orange National Park, Amapá state, north Brazil. These records from the eastern part of the Guiana Shield suggest a northward extension of the core southern distribution.
Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escri... more Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escrita del editor. Copyright © 2010 Fundación Universitaria San Martín Derechos reservados conforme a la ley Primera edición Bogotá, Colombia ISBN libro impreso 978-958-721-020-0 ISBEN libro versión digital 978-958-721-021-7 Impresión Gráficas San Martín
Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escri... more Prohibida la reproducción total o parcial de esta obra por cualquier medio sin autorización escrita del editor. Copyright © 2010 Fundación Universitaria San Martín Derechos reservados conforme a la ley Primera edición Bogotá, Colombia ISBN libro impreso 978-958-721-020-0 ISBN libro versión digital 978-958-721-021-7 Impresión Gráficas San Martín