16 research outputs found
Phylogenetics and phylogeography of the Hipposideros commersoni (Chiroptera) species complex with special reference to Malagasy populations.
Doctoral Degree. University of KwaZulu-Natal, Durban.ABSTRACT
Hipposideros commersoni is endemic to Madagascar and is relatively common in the western portion of the island, where it is found in different habitats from sea level to 1325 m. A previous study on patterns of morphological variation within the species highlighted the presence of two distinct morphotypes larger individuals in the north of Madagascar and smaller individuals in the south. Molecular techniques using DNA sequence data in combination with morphology have been previously used to identify cryptic hipposiderid species. This thesis presents the results of analyses based on molecular data and craniodental measurements in H. commersoni occurring on Madagascar, and related African forms. The molecular analyses suggest that H. commersoni with respect to Madagascar is paraphyletic, with strong support for the presence of independently evolving lineages. Two individuals amongst those sequenced from areas in the south of Madagascar represent a unique evolutionary lineage (Clade A), distinct from other H. commersoni, and has been recently named as a new species, H. cryptovalorona. This species is sister to H. gigas and H. vittatus, both restricted to Africa. Within H. commersoni, the molecular data support two geographically distributed clades -- one in the south (Clade B) and the other in the north (Clade C). Morphometric data were consistent with the molecular analyses, suggesting a northâsouth break within H. commersoni. Bayesian clustering analysis showed that H. commersoni comprised four main lineages: B1, B2, B3 and C. The most recent common ancestor of H. commersoni was dated to 3.33 million years ago or the mid-Pliocene. Population expansion events were inferred for groups B1, B2 and B3 from approximately 127,600 (group B1) to 6,870 years BP (group B2). Conflicting results were obtained from Bayesian clustering and AMOVA analyses; strong population genetic structure was obtained from the former but not the latter. Sequence data indicated that genetic subdivisions failed to support an isolation-by-distance model. Lineage dispersal, genetic divergence and expansion events of H. commersoni are likely to be associated with Plio-Pleistocene climate fluctuations. Our data indicate the northern and the central western regions of Madagascar may have acted as refugia for this species during the Plio-Pleistocene.Abstract available in the PDF
Lois et rĂšglements sur la faune sauvage Ă Madagascar : ProgrĂšs accomplis et besoins du futur
In many countries wildlife species are threatened by hunting for meat or collection for the pet trade. Wildlife laws which control where these activities can occur, limit the timing of exploitation, or provide strict protection for some species are therefore an important component of the conservation strategy. However it is important that these wildlife laws reflect the ecology and threat status of the species concerned, and that they are aligned with any relevant international conventions. In this article we discuss the legal framework for exploiting and protecting tetrapod species in Madagascar. We review the 2006 update to wildlife legislation with respect to international treaties, other national legislation and the IUCN Red List of Threatened Species. We also present a summary of the different categories of hunting (sport, commercial, scientific, and subsistence) and the control of hunting in protected areas. Madagascar has a sound legal framework for the use and protection of wildlife and the classification of species into protected, pest and legally hunted is clear and mostly fits well with the speciesâ classification according to the IUCN Red List and CITES. A revision of the protected species list managed is needed however to (i) include marine mammals that are protected by fisheries law and the Convention on Migratory Species and to (ii) better reflect the rights of people whose livelihoods rely heavily on the income or protein derived from hunting animals. Renewed effort to communicate and enforce wildlife legislation is needed, especially regarding the illegal hunting and export of protected species. This would also support the ongoing initiative to expand the protected area system and could be integrated into a revised National Biodiversity Strategy and Action Plan that Madagascar should produce for 2011-2020 as part of its commitment to implementing the Convention on Biological Diversity. RĂSUMĂLes lois et rĂšglements dĂ©terminant les niveaux de protection des espĂšces de la faune et de la flore sauvages sont des indicateurs importants de lâimportance quâaccorde un pays Ă la conservation de sa biodiversitĂ©. Dans cette revue, nous Ă©valuons la cohĂ©rence entre les lois et rĂšglements portant sur la gestion de la faune sauvage Ă Madagascar, en considĂ©rant la lĂ©gislation nationale, les conventions internationales ratifiĂ©es et la Liste Rouge de lâUICN pour les confronter aux rĂ©alitĂ©s locales. Suite Ă nos analyses, nous pouvons conclure que Madagascar dispose dâun cadre juridique adĂ©quat pour rĂ©glementer la protection et lâexploitation des animaux sauvages. Cependant, des rĂ©visions et mises Ă jour sont nĂ©cessaires, particuliĂšrement en ce qui concerne la liste des espĂšces dans les diffĂ©rentes catĂ©gories et la facilitation de la mise en application de la loi
Rapid ecological specialization despite constant population sizes
Background
The bushbuck, Tragelaphus scriptus, is a widespread and ecologically diverse ungulate species complex within the spiral-horned antelopes. This species was recently found to consist of two genetically divergent but monophyletic lineages, which are paraphyletic at mitochondrial (mt)DNA owing to an ancient interspecific hybridization event. The Scriptus lineage (T. s. scriptus) inhabits the north-western half of the African continent while Sylvaticus (T. s. sylvaticus) is found in the south-eastern half. Here we test hypotheses of historical demography and adaptation in bushbuck using a higher-resolution framework, with four nuclear (MGF, PRKCI, SPTBN, and THY) and three new mitochondrial markers (cytochrome b, 12S rRNA, and 16S rRNA).
Methods
Genealogies were reconstructed for the mitochondrial and nuclear data sets, with the latter dated using fossil calibration points. We also inferred the demographic history of Scriptus and Sylvaticus using coalescent-based methods. To obtain an overview of the origins and ancestral colonisation routes of ancestral bushbuck sequences across geographic space, we conducted discrete Bayesian phylogeographic and statistical dispersal-vicariance analyses on our nuclear DNA data set.
Results
Both nuclear DNA and mtDNA support previous findings of two genetically divergent Sylvaticus and Scriptus lineages. The three mtDNA loci confirmed 15 of the previously defined haplogroups, including those with convergent phenotypes. However, the nuclear tree showed less phylogenetic resolution at the more derived parts of the genealogy, possibly due to incomplete lineage sorting of the slower evolving nuclear genome. The only exception to this was the montane Menelikâs bushbuck (Sylvaticus) of the Ethiopian highlands, which formed a monophyletic group at three of four nuclear DNA loci. We dated the coalescence of the two lineages to a common ancestor âŒ2.54 million years ago. Both marker sets revealed similar demographic histories of constant population size over time. We show that the bushbuck likely originated in East Africa, with Scriptus dispersing to colonise suitable habitats west of the African Rift and Sylvaticus radiating from east of the Rift into southern Africa via a series of mainly vicariance events.
Discussion
Despite lower levels of genetic structure at nuclear loci, we confirmed the independent evolution of the Menelikâs bushbuck relative to the phenotypically similar montane bushbuck in East Africa, adding further weight to previous suggestions of convergent evolution within the bushbuck complex. Perhaps the most surprising result of our analysis was that both Scriptus and Sylvaticus populations remained relatively constant throughout the Pleistocene, which is remarkable given that this was a period of major climatic and tectonic change in Africa, and responsible for driving the evolution of much of the continentâs extant large mammalian diversity
Phylogeography and population genetics of the endemic Malagasy bat, Macronycteris commersoni s.s. (Chiroptera: Hipposideridae)
Macronycteris commersoni (Hipposideridae), a bat species endemic to Madagascar, is widespread across the island and utilizes a range of habitat types including open woodland, degraded habitats, and forested areas from sea level to 1,325 m. Despite being widely distributed, there is evidence that M. commersoni exhibits morphological and bioacoustic variation across its geographical range. We investigated the fine-scale phylogeographic structure of populations in the western half of the island using extensive spatial sampling and sequence data from two mitochondrial DNA regions. Our results indicated several lineages within M. commersoni. Individuals collected from northern Madagascar formed a single monophyletic clade (clade C). A second clade (clade B) included individuals collected from the south-western portion of the island. This second clade displayed more phylogeographical partitioning with differences in mtDNA haplotypes frequency detected between populations collected in different bioclimatic regions. Lineage dispersal, genetic divergence, and timing of expansion events of M. commersoni were probably associated with Pleistocene climate fluctuations. Our data suggest that the northern and the central western regions of Madagascar may have acted as refugia for this species during periods of cooler and drier climate conditions associated with the Pleistocene
A conservation assessment of Rousettus madagascariensis (Grandidier, 1929, Pteropodidae) roosts in eastern Madagascar
We visited four cave roosts of the near threatened, and endemic, fruit bat Rousettus madagascariensis over a five year period and found major threats to the bats from hunting and deforestation. The conservation of this species is particularly challenging because it is legally hunted inside its cave roosts. Although provisional protected area status was obtained for two sites with community support, hunting continued. R. madagascariensis roosts were associated with humid forest and the loss of vegetation around caves rendered them unsuitable for the bats at two abandoned sites. A few individual hunters can have a rapid and destructive impact on R. madagascariensis roosts and future initiatives in this area should involve working with hunters to develop realistic solutions to reduce hunting. These efforts need to be supported by habitat protection measures. RĂSUMĂ LâespĂšce de chauve-souris frugivore Quasi MenacĂ©e Rousettus madagascariensis est endĂ©mique Ă Madagascar. Nous avons Ă©tudiĂ© quatre gĂźtes dans des grottes oĂč cette espĂšce a Ă©tabli des dortoirs diurnes en procĂ©dant Ă des visites multiples au cours dâune pĂ©riode de cinq ans et avons trouvĂ© que la chasse et la dĂ©forestation constituaient les principales menaces pesant sur R. madagascariensis. La conservation de cette espĂšce est particuliĂšrement difficile dans la mesure oĂč la chasse dans ses dortoirs ou gĂźtes est permise. Bien que les deux sites abritant lâespĂšce bĂ©nĂ©ficient du statut de Nouvelle Aire ProtĂ©gĂ©e avec le soutien de la communautĂ© locale, la chasse ne cesse de sâintensifier. Les gĂźtes de R. madagascariensis sont associĂ©s Ă la forĂȘt humide, de sorte que la disparition de la vĂ©gĂ©tation arborĂ©e autour de deux de ces gĂźtes les a rendus impropres Ă hĂ©berger R. madagascariensis qui a fini par les abandonner. La disparition de la vĂ©gĂ©tation arborĂ©e autour du gĂźte pourrait ĂȘtre Ă lâorigine dâun changement de microclimat Ă lâintĂ©rieur de la grotte qui constitue le gĂźte diurne. Les activitĂ©s de certains chasseurs peuvent aussi avoir un impact destructif rapide sur les gĂźtes de R. madagascariensis et des initiatives Ă mener conjointement avec les chasseurs sont nĂ©cessaires pour Ă©laborer des mesures rĂ©alistes afin de rĂ©duire la chasse. De tels efforts doivent ĂȘtre Ă©tendus et appuyĂ©s par des mesures de protection de l'habitat car plusieurs autres gĂźtes pourraient exister dans les forĂȘts du versant est de Madagascar et subir les mĂȘmes pressions anthropiques. Des recherches rĂ©centes ont Ă©galement montrĂ© que lâhistoire naturelle de R. madagascariensis est Ă©troitement liĂ©e Ă la forĂȘt naturelle, de sorte que la perte de la biodiversitĂ© de la forĂȘt naturelle malgache menace les plantes dont se nourrit cette espĂšce ainsi que lâĂ©quilibre de lâensemble de lâĂ©cosystĂšme dont elle dĂ©pend.
Preliminary fish survey of Lac Tseny in northwestern Madagascar
We surveyed the fish fauna of Lac Tseny, in the Sofia Region of northwestern Madagascar, during October 2010 by observing commercial catches and targeted netting of areas used by endemic species. We recorded seven native fish species at the lake, including three endemic cichlids, a herring and a catfish. We confirmed the continued survival of the Critically Endangered Paretroplus menarambo, as well as the presence of a Paretroplus taxon that may be new to science. The commercial fishery in the lake is sustained by introduced tilapiines and the native Savagella robusta. The three endemic cichlids (Paretroplus spp.) were not targeted by commercial fishermen, but when caught in small numbers were retained for domestic consumption. Submerged trees in the west of the lake restrict fishing with nets and probably provide important habitat for P. menarambo. Priority next steps at the lake include (i) additional surveys and biological studies of the endemic fish species and the Critically Endangered Madagascar big-headed turtle, Erymnochelys madagascariensis, (ii) clarification of the taxonomic status of Paretroplus cf. kieneri and, should it prove a new taxon, its formal scientific description, and (iii) continued engagement with fishing communities and authorities to promote practices that benefit livelihoods and the survival of threatened fish species.  RĂSUMĂ La composition spĂ©cifique de l'ichtyofaune du lac Tseny, dans l'ouest de Madagascar (rĂ©gion de Sofia) a Ă©tĂ© inventoriĂ©e au cours du mois dâoctobre 2010, en observant les prises des pĂȘcheurs et des pĂȘches ciblĂ©es sur les espĂšces endĂ©miques. Sept espĂšces de poissons indigĂšnes ont Ă©tĂ© observĂ©s, dont trois cichlidĂ©s endĂ©miques (Paretroplus menarambo, Paretroplus lamenabe et Paretroplus cf. kieneri), un hareng indigĂšne (Sauvagella robusta) et un poisson-chat (Arius madagascariensis). Deux de ces espĂšces sont classĂ©es comme MenacĂ©es dans la Liste Rouge de l'UICN : P. menarambo est une espĂšce en Danger Critique dâExtinction qui nâest connue que du lac Tseny et A. madagascariensis est une espĂšce en Danger dâExtinction et endĂ©mique de la rĂ©gion de Sofia. Un des poissons que nous avons inventoriĂ© dans le genre Paretroplus semble ĂȘtre une forme non dĂ©crite. Les pĂȘcheurs ont indiquĂ© que P. menarambo est associĂ© Ă des arbres immergĂ©s le long de la rive occidentale du lac qui offrent un habitat propice Ă la reproduction et Ă l'alimentation. Ces arbres immergĂ©s empĂȘchent l'utilisation des filets pour la pĂȘche et limitent ainsi la pression de pĂȘche qui sâexerce sur cette espĂšce. Les trois espĂšces endĂ©miques de Paretroplus sont prisĂ©es par les pĂȘcheurs qui les gardent pour leur consommation personnelle plutĂŽt que de les vendre. La pĂȘche commerciale pratiquĂ©e dans le lac semble pĂ©renne grĂące Ă la prĂ©sence de tilapias allogĂšnes et du hareng indigĂšne (Sauvagella robusta) qui approvisionnent les marchĂ©s de poisson local (Tsaratanana), rĂ©gionaux (Boriziny et Mandritsara) et national (Antananarivo). Les populations locales ont rapportĂ© que la surpĂȘche, l'immigration, lâutilisation illĂ©gale de filets Ă petit maillage et le non respect de la saison de fermeture de la pĂȘche Ă©taient les principales menaces pesant sur lâichtyofaune du lac Tseny. Une baisse de la pĂȘche commerciale pourrait entraĂźner une ruĂ©e vers les espĂšces endĂ©miques et l'ouverture des zones dâarbres immergĂ©s pour la pĂȘche. Le lac Tseny abrite un assemblage unique de poissons qui doivent ĂȘtre protĂ©gĂ©s dans leur habitat qui est essentiel aux cichlidĂ©s endĂ©miques par le maintien d'une pĂȘche commerciale pĂ©renne. Les prochaines Ă©tapes Ă mener en prioritĂ© pour le lac incluent : (i) des Ă©tudes supplĂ©mentaires sur la biologie des poissons endĂ©miques et de la PodocnĂ©mide de Madagascar (Erymnochelys madagascariensis), une tortue en Danger Critique dâExtinction, (ii) la clarification du statut taxinomique de Paretroplus cf. kieneri qui pourrait ĂȘtre une nouvelle espĂšce et sa description, le cas Ă©chĂ©ant, et (iii) lâengagement continu avec les communautĂ©s de pĂȘcheurs et les autoritĂ©s locales pour promouvoir des pratiques Ă©quitables en faveur des populations riveraines et pour la survie des espĂšces de poissons menacĂ©es
Preliminary fish survey of Lac Tseny in northwestern Madagascar
We surveyed the fish fauna of Lac Tseny, in the Sofia Region of northwestern Madagascar, during October 2010 by observing commercial catches and targeted netting of areas used by endemic species. We recorded seven native fish species at the lake, including three endemic cichlids, a herring and a catfish. We confirmed the continued survival of the Critically Endangered Paretroplus menarambo, as well as the presence of a Paretroplus taxon that may be new to science. The commercial fishery in the lake is sustained by introduced tilapiines and the native Savagella robusta. The three endemic cichlids (Paretroplus spp.) were not targeted by commercial fishermen, but when caught in small numbers were retained for domestic consumption. Submerged trees in the west of the lake restrict fishing with nets and probably provide important habitat for P. menarambo. Priority next steps at the lake include (i) additional surveys and biological studies of the endemic fish species and the Critically Endangered Madagascar big-headed turtle, Erymnochelys madagascariensis, (ii) clarification of the taxonomic status of Paretroplus cf. kieneri and, should it prove a new taxon, its formal scientific description, and (iii) continued engagement with fishing communities and authorities to promote practices that benefit livelihoods and the survival of threatened fish species.  RĂSUMĂ La composition spĂ©cifique de l'ichtyofaune du lac Tseny, dans l'ouest de Madagascar (rĂ©gion de Sofia) a Ă©tĂ© inventoriĂ©e au cours du mois dâoctobre 2010, en observant les prises des pĂȘcheurs et des pĂȘches ciblĂ©es sur les espĂšces endĂ©miques. Sept espĂšces de poissons indigĂšnes ont Ă©tĂ© observĂ©s, dont trois cichlidĂ©s endĂ©miques (Paretroplus menarambo, Paretroplus lamenabe et Paretroplus cf. kieneri), un hareng indigĂšne (Sauvagella robusta) et un poisson-chat (Arius madagascariensis). Deux de ces espĂšces sont classĂ©es comme MenacĂ©es dans la Liste Rouge de l'UICN : P. menarambo est une espĂšce en Danger Critique dâExtinction qui nâest connue que du lac Tseny et A. madagascariensis est une espĂšce en Danger dâExtinction et endĂ©mique de la rĂ©gion de Sofia. Un des poissons que nous avons inventoriĂ© dans le genre Paretroplus semble ĂȘtre une forme non dĂ©crite. Les pĂȘcheurs ont indiquĂ© que P. menarambo est associĂ© Ă des arbres immergĂ©s le long de la rive occidentale du lac qui offrent un habitat propice Ă la reproduction et Ă l'alimentation. Ces arbres immergĂ©s empĂȘchent l'utilisation des filets pour la pĂȘche et limitent ainsi la pression de pĂȘche qui sâexerce sur cette espĂšce. Les trois espĂšces endĂ©miques de Paretroplus sont prisĂ©es par les pĂȘcheurs qui les gardent pour leur consommation personnelle plutĂŽt que de les vendre. La pĂȘche commerciale pratiquĂ©e dans le lac semble pĂ©renne grĂące Ă la prĂ©sence de tilapias allogĂšnes et du hareng indigĂšne (Sauvagella robusta) qui approvisionnent les marchĂ©s de poisson local (Tsaratanana), rĂ©gionaux (Boriziny et Mandritsara) et national (Antananarivo). Les populations locales ont rapportĂ© que la surpĂȘche, l'immigration, lâutilisation illĂ©gale de filets Ă petit maillage et le non respect de la saison de fermeture de la pĂȘche Ă©taient les principales menaces pesant sur lâichtyofaune du lac Tseny. Une baisse de la pĂȘche commerciale pourrait entraĂźner une ruĂ©e vers les espĂšces endĂ©miques et l'ouverture des zones dâarbres immergĂ©s pour la pĂȘche. Le lac Tseny abrite un assemblage unique de poissons qui doivent ĂȘtre protĂ©gĂ©s dans leur habitat qui est essentiel aux cichlidĂ©s endĂ©miques par le maintien d'une pĂȘche commerciale pĂ©renne. Les prochaines Ă©tapes Ă mener en prioritĂ© pour le lac incluent : (i) des Ă©tudes supplĂ©mentaires sur la biologie des poissons endĂ©miques et de la PodocnĂ©mide de Madagascar (Erymnochelys madagascariensis), une tortue en Danger Critique dâExtinction, (ii) la clarification du statut taxinomique de Paretroplus cf. kieneri qui pourrait ĂȘtre une nouvelle espĂšce et sa description, le cas Ă©chĂ©ant, et (iii) lâengagement continu avec les communautĂ©s de pĂȘcheurs et les autoritĂ©s locales pour promouvoir des pratiques Ă©quitables en faveur des populations riveraines et pour la survie des espĂšces de poissons menacĂ©es