This study was carried out in a savannah/forest mosaic at the Lope National Park, in Gabon. Ninet... more This study was carried out in a savannah/forest mosaic at the Lope National Park, in Gabon. Ninety-six pitfall traps were used, 39 in gallery forest and 57 in savannah. The foragers of eighteen morph species were collected in both habitats: 16 in gallery forest and 15 in savannah. Wasmannia auropunctata is the most frequent in the gallery forest, recorded in 90% of the samples, against 55% in savannah. On the other hand, Pheidole megacephala was found in 80% of the samples, Camponotus negus in 75% and Polyrhachis latispina in 60%, all of them more frequent in savannah than in gallery forest. Generally speaking, the other species were found in both habitats, except Camponotus sericeus which forages only in the savannah. Interactions in the savannah are much more complex than in the gallery forest.
Impacts écologique et comportemental de la fourni envahissante Wasmannia auropunctata sur une espèce arboricole, Tetraponera aethiops au Gabon
Originaire d’Amerique tropicale, Wasmannia auropunctata (Roger) a ete signalee au Gabon depuis 19... more Originaire d’Amerique tropicale, Wasmannia auropunctata (Roger) a ete signalee au Gabon depuis 1914. Dans un premier temps, nous avons caracterise la distribution de cette fourmi a travers tout le territoire gabonais et dans des ecosystemes particuliers, les mosaiques « foret-galerie savane ». Il resulte que W. Auropunctata a colonise tout le territoire gabonais pres d’un siecle apres son introduction. Dans un deuxieme temps, nous avons evalue le niveau d’agressivite entre les ouvrieres de W. Auropunctata issues de populations differentes. Malgre l’existence d’une faible agressivite entre individus issus des colonies differentes de W. Auropunctata au Gabon, les resultats de l’etude chimique et comportementale montrent l'existence d'une certaine capacite de discrimination entre les ouvrieres provenant de populations separees. Ceci placerait les populations gabonaises dans un statut intermediaire de celles de la Nouvelle Caledonie et d'Israel (supercolonie) et de celles de...
We recorded ground-foraging ant species in forest and savannah habitats along a 52-km-long road p... more We recorded ground-foraging ant species in forest and savannah habitats along a 52-km-long road planned for upgrade in the buffer zone of the Moukalaba-Doudou National Park in southwest Gabon. Sixty stations were established with three sampling points on each side of the future road and baited with peanut butter to record the presence of invasive Wasmannia auropunctata (Roger, 1863). We documented 46 ant species including one genus and eight species not previously reported in Gabon, but no evidence of the presence of W. auropunctata. We also found species known to have an opportunistic behaviour such as Cardiocondyla emeryi (Forel, 1881), Tetramorium simillimum (Smith, 1851) and Trichomyrmex destructor (Jerdon, 1851). Species richness in forested stations was significantly higher than in savannah. Among the most common ant species in the area, we identified 13 associated with forests, eight associated with savannahs and one generalist. Four species were highly tolerant to human disturbance. Our study, even if biased towards stress-tolerant species, provides new insights about ant species associations with habitats and contributes to the establishment of a reference system to classify African ant species that could be used to monitor the success of restoration of areas impacted by human activities.
As a Co authour : The first public product of the Intergovernmental Platform on
Biodiversity and... more As a Co authour : The first public product of the Intergovernmental Platform on
Biodiversity and Ecosystem Services (IPBES) is its Conceptual
Framework. This conceptual and analytical tool, presented
here in detail, will underpin all IPBES functions and provide
structure and comparability to the syntheses that IPBES will
produce at different spatial scales, on different themes, and in
different regions. Salient innovative aspects of the IPBES Conceptual Framework are its transparent and participatory
construction process and its explicit consideration of diverse
scientific disciplines, stakeholders, and knowledge systems,
including indigenous and local knowledge. Because the focus
on co-construction of integrative knowledge is shared by an
increasing number of initiatives worldwide, this framework
should be useful beyond IPBES, for the wider research and knowledge-policy communities working on the links between
nature and people, such as natural, social and engineering
scientists, policy-makers at different levels, and decisionmakers
in different sectors of society.
This study was carried out in a savannah/forest mosaic at the Lopé National Park, in Gabon. Ninet... more This study was carried out in a savannah/forest mosaic at the Lopé National Park, in Gabon. Ninety-six pitfall traps were used, 39 in gallery forest and 57 in savannah. The foragers of eighteen morph species were collected in both habitats: 16 in gallery forest and 15 in savannah. Wasmannia auropunctata is the most frequent in the gallery forest, recorded in 90% of the samples, against 55% in savannah. On the other hand, Pheidole megacephala was found in 80% of the samples, Camponotus negus in 75% and Polyrhachis latispina in 60%, all of them more frequent in savannah than in gallery forest. Generally speaking, the other species were found in both habitats, except Camponotus sericeus which forages only in the savannah. Interactions in the savannah are
Wasmannia auropunctata (Roger 1863) is an ant originating from the South America. It was introduc... more Wasmannia auropunctata (Roger 1863) is an ant originating from the South America. It was introduced in Gabon about 1920 by agronomists who used it as a biological control agent against parasitic insects of the cacao-tree. Now, this ant is found even in forest belt out of the old plantations of cacao-trees. Since 1984, its presence was announced in the national park of Lope which is a protected reserve of Gabon. Former studies carried out in New Caledonia showed that the presence of Wauropunctata has important consequences on the biodiversity because it made disappear the ants of this area. What can thus be the impact of its presence in the Lope zone? These preliminary studies of the impact of W auropunctata on the biodiversity of Lope consisted to evaluate the dispersion of this species and the relative density of the other ant species of involved ants on the site. The results show that Wauropunctata is distributed along on a decreasing gradient from the introduction point until 120...
Biological invasions are generally thought to occur after human aided migration to a new range. H... more Biological invasions are generally thought to occur after human aided migration to a new range. However, human activities prior to migration may also play a role. We studied here the evolutionary genetics of introduced populations of the invasive ant Wasmannia auropunctata at a worldwide scale. Using microsatellite markers, we reconstructed the main routes of introduction of the species. We found three main routes of introduction, each of them strongly associated to human history and trading routes. We also demonstrate the overwhelming occurrence of male and female clonality in introduced populations of W. auropunctata, and suggest that this particular reproduction system is under selection in human-modified habitats. Together with previous researches focused on native populations, our results suggest that invasive clonal populations may have evolved within human modified habitats in the native range, and spread further from there. The evolutionarily most parsimonious scenario for the emergence of invasive populations of the little fire ant might thus be a two-step process. The W. auropunctata case illustrates the central role of humans in biological change, not only due to changes in migration patterns, but also in selective pressures over species.
1. In tropical West Africa, the ant Tetraponera aethiops obligately inhabits the domatia of Barte... more 1. In tropical West Africa, the ant Tetraponera aethiops obligately inhabits the domatia of Barteria fistulosa trees, aggressively defending the trees from herbivory and pruning off lianas.
Arthropods were monitored by local parataxonomists at 12 sites of increasing anthropogenic distur... more Arthropods were monitored by local parataxonomists at 12 sites of increasing anthropogenic disturbance (old and young secondary forests, savanna and cultivated gardens) at Gamba, Gabon. We report on the discriminatory power of different data sets with regard to the classification of sites along the disturbance gradient, using preliminary data accounting for 13 surveys and 142 425 arthropods collected by Malaise, pitfall and yellow-pan traps. We compared the performance of different data sets. These were based upon ordinal, familial and guild composition, or upon 22 target taxa sorted to morphospecies and either considered in toto or grouped within different functional guilds. Finally we evaluated 'predictor sets' made up of a few families or other target taxa, selected on the basis of their indicator value index. Although the discriminatory power of data sets based on ordinal categories and guilds was low, that of target taxa belonging to chewers, parasitoids and predators was much higher. The data sets that best discriminated among sites of differing degrees of disturbance were the restricted sets of indicator families and target taxa. This validates the concept of predictor sets for species-rich tropical systems. Including or excluding rare taxa in the analyses did not alter these conclusions. We conclude that calibration studies similar to ours are needed elsewhere in the tropics and that this strategy will allow to devise a representative and efficient biotic index for the biological monitoring of terrestrial arthropod assemblages in the tropics.
This study was carried out in a savannah/forest mosaic at the Lope National Park, in Gabon. Ninet... more This study was carried out in a savannah/forest mosaic at the Lope National Park, in Gabon. Ninety-six pitfall traps were used, 39 in gallery forest and 57 in savannah. The foragers of eighteen morph species were collected in both habitats: 16 in gallery forest and 15 in savannah. Wasmannia auropunctata is the most frequent in the gallery forest, recorded in 90% of the samples, against 55% in savannah. On the other hand, Pheidole megacephala was found in 80% of the samples, Camponotus negus in 75% and Polyrhachis latispina in 60%, all of them more frequent in savannah than in gallery forest. Generally speaking, the other species were found in both habitats, except Camponotus sericeus which forages only in the savannah. Interactions in the savannah are much more complex than in the gallery forest.
Impacts écologique et comportemental de la fourni envahissante Wasmannia auropunctata sur une espèce arboricole, Tetraponera aethiops au Gabon
Originaire d’Amerique tropicale, Wasmannia auropunctata (Roger) a ete signalee au Gabon depuis 19... more Originaire d’Amerique tropicale, Wasmannia auropunctata (Roger) a ete signalee au Gabon depuis 1914. Dans un premier temps, nous avons caracterise la distribution de cette fourmi a travers tout le territoire gabonais et dans des ecosystemes particuliers, les mosaiques « foret-galerie savane ». Il resulte que W. Auropunctata a colonise tout le territoire gabonais pres d’un siecle apres son introduction. Dans un deuxieme temps, nous avons evalue le niveau d’agressivite entre les ouvrieres de W. Auropunctata issues de populations differentes. Malgre l’existence d’une faible agressivite entre individus issus des colonies differentes de W. Auropunctata au Gabon, les resultats de l’etude chimique et comportementale montrent l'existence d'une certaine capacite de discrimination entre les ouvrieres provenant de populations separees. Ceci placerait les populations gabonaises dans un statut intermediaire de celles de la Nouvelle Caledonie et d'Israel (supercolonie) et de celles de...
We recorded ground-foraging ant species in forest and savannah habitats along a 52-km-long road p... more We recorded ground-foraging ant species in forest and savannah habitats along a 52-km-long road planned for upgrade in the buffer zone of the Moukalaba-Doudou National Park in southwest Gabon. Sixty stations were established with three sampling points on each side of the future road and baited with peanut butter to record the presence of invasive Wasmannia auropunctata (Roger, 1863). We documented 46 ant species including one genus and eight species not previously reported in Gabon, but no evidence of the presence of W. auropunctata. We also found species known to have an opportunistic behaviour such as Cardiocondyla emeryi (Forel, 1881), Tetramorium simillimum (Smith, 1851) and Trichomyrmex destructor (Jerdon, 1851). Species richness in forested stations was significantly higher than in savannah. Among the most common ant species in the area, we identified 13 associated with forests, eight associated with savannahs and one generalist. Four species were highly tolerant to human disturbance. Our study, even if biased towards stress-tolerant species, provides new insights about ant species associations with habitats and contributes to the establishment of a reference system to classify African ant species that could be used to monitor the success of restoration of areas impacted by human activities.
As a Co authour : The first public product of the Intergovernmental Platform on
Biodiversity and... more As a Co authour : The first public product of the Intergovernmental Platform on
Biodiversity and Ecosystem Services (IPBES) is its Conceptual
Framework. This conceptual and analytical tool, presented
here in detail, will underpin all IPBES functions and provide
structure and comparability to the syntheses that IPBES will
produce at different spatial scales, on different themes, and in
different regions. Salient innovative aspects of the IPBES Conceptual Framework are its transparent and participatory
construction process and its explicit consideration of diverse
scientific disciplines, stakeholders, and knowledge systems,
including indigenous and local knowledge. Because the focus
on co-construction of integrative knowledge is shared by an
increasing number of initiatives worldwide, this framework
should be useful beyond IPBES, for the wider research and knowledge-policy communities working on the links between
nature and people, such as natural, social and engineering
scientists, policy-makers at different levels, and decisionmakers
in different sectors of society.
This study was carried out in a savannah/forest mosaic at the Lopé National Park, in Gabon. Ninet... more This study was carried out in a savannah/forest mosaic at the Lopé National Park, in Gabon. Ninety-six pitfall traps were used, 39 in gallery forest and 57 in savannah. The foragers of eighteen morph species were collected in both habitats: 16 in gallery forest and 15 in savannah. Wasmannia auropunctata is the most frequent in the gallery forest, recorded in 90% of the samples, against 55% in savannah. On the other hand, Pheidole megacephala was found in 80% of the samples, Camponotus negus in 75% and Polyrhachis latispina in 60%, all of them more frequent in savannah than in gallery forest. Generally speaking, the other species were found in both habitats, except Camponotus sericeus which forages only in the savannah. Interactions in the savannah are
Wasmannia auropunctata (Roger 1863) is an ant originating from the South America. It was introduc... more Wasmannia auropunctata (Roger 1863) is an ant originating from the South America. It was introduced in Gabon about 1920 by agronomists who used it as a biological control agent against parasitic insects of the cacao-tree. Now, this ant is found even in forest belt out of the old plantations of cacao-trees. Since 1984, its presence was announced in the national park of Lope which is a protected reserve of Gabon. Former studies carried out in New Caledonia showed that the presence of Wauropunctata has important consequences on the biodiversity because it made disappear the ants of this area. What can thus be the impact of its presence in the Lope zone? These preliminary studies of the impact of W auropunctata on the biodiversity of Lope consisted to evaluate the dispersion of this species and the relative density of the other ant species of involved ants on the site. The results show that Wauropunctata is distributed along on a decreasing gradient from the introduction point until 120...
Biological invasions are generally thought to occur after human aided migration to a new range. H... more Biological invasions are generally thought to occur after human aided migration to a new range. However, human activities prior to migration may also play a role. We studied here the evolutionary genetics of introduced populations of the invasive ant Wasmannia auropunctata at a worldwide scale. Using microsatellite markers, we reconstructed the main routes of introduction of the species. We found three main routes of introduction, each of them strongly associated to human history and trading routes. We also demonstrate the overwhelming occurrence of male and female clonality in introduced populations of W. auropunctata, and suggest that this particular reproduction system is under selection in human-modified habitats. Together with previous researches focused on native populations, our results suggest that invasive clonal populations may have evolved within human modified habitats in the native range, and spread further from there. The evolutionarily most parsimonious scenario for the emergence of invasive populations of the little fire ant might thus be a two-step process. The W. auropunctata case illustrates the central role of humans in biological change, not only due to changes in migration patterns, but also in selective pressures over species.
1. In tropical West Africa, the ant Tetraponera aethiops obligately inhabits the domatia of Barte... more 1. In tropical West Africa, the ant Tetraponera aethiops obligately inhabits the domatia of Barteria fistulosa trees, aggressively defending the trees from herbivory and pruning off lianas.
Arthropods were monitored by local parataxonomists at 12 sites of increasing anthropogenic distur... more Arthropods were monitored by local parataxonomists at 12 sites of increasing anthropogenic disturbance (old and young secondary forests, savanna and cultivated gardens) at Gamba, Gabon. We report on the discriminatory power of different data sets with regard to the classification of sites along the disturbance gradient, using preliminary data accounting for 13 surveys and 142 425 arthropods collected by Malaise, pitfall and yellow-pan traps. We compared the performance of different data sets. These were based upon ordinal, familial and guild composition, or upon 22 target taxa sorted to morphospecies and either considered in toto or grouped within different functional guilds. Finally we evaluated 'predictor sets' made up of a few families or other target taxa, selected on the basis of their indicator value index. Although the discriminatory power of data sets based on ordinal categories and guilds was low, that of target taxa belonging to chewers, parasitoids and predators was much higher. The data sets that best discriminated among sites of differing degrees of disturbance were the restricted sets of indicator families and target taxa. This validates the concept of predictor sets for species-rich tropical systems. Including or excluding rare taxa in the analyses did not alter these conclusions. We conclude that calibration studies similar to ours are needed elsewhere in the tropics and that this strategy will allow to devise a representative and efficient biotic index for the biological monitoring of terrestrial arthropod assemblages in the tropics.
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Papers by Jean Mikissa
Biodiversity and Ecosystem Services (IPBES) is its Conceptual
Framework. This conceptual and analytical tool, presented
here in detail, will underpin all IPBES functions and provide
structure and comparability to the syntheses that IPBES will
produce at different spatial scales, on different themes, and in
different regions. Salient innovative aspects of the IPBES Conceptual Framework are its transparent and participatory
construction process and its explicit consideration of diverse
scientific disciplines, stakeholders, and knowledge systems,
including indigenous and local knowledge. Because the focus
on co-construction of integrative knowledge is shared by an
increasing number of initiatives worldwide, this framework
should be useful beyond IPBES, for the wider research and knowledge-policy communities working on the links between
nature and people, such as natural, social and engineering
scientists, policy-makers at different levels, and decisionmakers
in different sectors of society.
Biodiversity and Ecosystem Services (IPBES) is its Conceptual
Framework. This conceptual and analytical tool, presented
here in detail, will underpin all IPBES functions and provide
structure and comparability to the syntheses that IPBES will
produce at different spatial scales, on different themes, and in
different regions. Salient innovative aspects of the IPBES Conceptual Framework are its transparent and participatory
construction process and its explicit consideration of diverse
scientific disciplines, stakeholders, and knowledge systems,
including indigenous and local knowledge. Because the focus
on co-construction of integrative knowledge is shared by an
increasing number of initiatives worldwide, this framework
should be useful beyond IPBES, for the wider research and knowledge-policy communities working on the links between
nature and people, such as natural, social and engineering
scientists, policy-makers at different levels, and decisionmakers
in different sectors of society.