Morphological differences and identification of Jumellea rossii and Jumellea fragrans (Orchidaceae) in Reunion Island: implications for conservation

Conservation strategies are not possible when there is confusion in the taxonomic status of a group of plants. Such confusion makes difficult for systematic biologists to identify functional biological entities. This is particularly true in the case of species that diversified fast due to adaptive radiation particularly plants from the oceanic islands. It is the case of certain orchids from Reunion Island. Among them, the “Faham” complex includes several taxa whose populations are situated at various elevations with morphological and reproductive variations. These taxa are actually merged into one name: Jumellea fragrans causing confusion in their taxonomic status. This confusion has caused numerous problems of identification and errors hindering the protection status of the species. In this study, we suggest to clarify the systematic position of the taxa composing complex Jumellea fragrans using a biometric approach at population scale. The objective is to identify morphological characters that allow distinguishing the taxa of the J. fragrans complex. Morphological characters (vegetative and floral) are measured on individuals from three natural populations representative of altitudinal range of the complex. Principal component analysis made on the characters show a separation of the individuals in two groups (Mare-Longue vs Basse-Vallée and Cilaos). Nine characters (on 14 measured) are significantly different between Mare-Longue population and the populations of Basse-Vallée and Cilaos and allow identifying both groups. Population of Mare-Longue belongs to the species Jumellea fragrans (Thouars) Schltr. and populations of Basse-Vallée and Cilaos belongs to the species Jumellea rossii Senghas. In terms of conservation, the first recommendation is to recognize two different species: J. rossii and J. fragrans. Moreover, putting J. fragrans into the « vulnerable » IUCN Red List category and the adoption of a protection status are recommended. Concerning J. rossii, more studies on geographical range and population dynamics are necessary to estimate the risk of extinction. In the same way, studies on genetic variability of both species would generate useful data for implementation of conservation strategiesLa clarification du statut taxinomique des espèces constitue un préambule nécessaire à la mise en place de mesures de conservation appropriées et efficaces, particulièrement dans les îles océaniques où la radiation adaptative rend difficile la reconnaissance des entités biologiques fonctionnelles. C’est le cas de certaines orchidées de La Réunion comme le « Faham » (Jumellea spp.) qui regroupe plusieurs taxons dont les populations se situent à différentes altitudes et semblent présenter des variations morphologiques et reproductives. Dans cette étude, nous proposons d’éclaircir la position systématique des taxons composant le complexe d’espèces regroupées sous le nom de « Faham » par le biais d’une approche morphométrique à l’échelle populationnelle et d’identifier des caractères morphologiques permettant de distinguer les différents taxons. Quatorze caractères (végétatifs et floraux) ont été mesurés sur 51 individus issus de trois populations naturelles représentatives de la distribution altitudinale du complexe. Des analyses multivariées effectuées sur ces caractères ont montré une séparation des individus en deux groupes (Mare-Longue d’une part, Basse-Vallée et Cilaos d’autre part). Neuf caractères sont significativement différents entre la population de Mare-Longue et les populations de Basse-Vallée et Cilaos et permettent de distinguer les deux groupes. La population de Mare-Longue appartiendrait à l’espèce Jumellea fragrans (Thouars) Schltr. et les populations de Basse-Vallée et Cilaos à l’espèce Jumellea rossii Senghas. En termes de conservation, la première recommandation est de reconnaître deux espèces bien distinctes : J. rossii et J. fragrans. D’autre part, l’inscription dans la catégorie « vulnérable » de la Liste Rouge de l’UICN et l’adoption d’un statut de protection semblent fortement recommandées pour J. fragrans. Concernant J. rossii, des connaissances approfondies sur la distribution géographique et la dynamique des populations de l’espèce s’avèrent nécessaires afin d’évaluer le risque d’extinction. Parallèlement, l’étude de la diversité génétique des deux espèces fournirait des données utiles pour la mise en oeuvre de plans de conservatio

Coevolution of Cyanogenic Bamboos and Bamboo Lemurs on Madagascar

Feeding strategies of specialist herbivores often originate from the coevolutionary arms race of plant defenses and counter-adaptations of herbivores. The interaction between bamboo lemurs and cyanogenic bamboos on Madagascar represents a unique system to study diffuse coevolutionary processes between mammalian herbivores and plant defenses. Bamboo lemurs have different degrees of dietary specialization while bamboos show different levels of chemical defense. In this study, we found variation in cyanogenic potential (HCNp) and nutritive characteristics among five sympatric bamboo species in the Ranomafana area, southeastern Madagascar. The HCNp ranged from 209±72 μmol cyanide* g-1 dwt in Cathariostachys madagascariensis to no cyanide in Bambusa madagascariensis. Among three sympatric bamboo lemur species, the greater bamboo lemur (Prolemur simus) has the narrowest food range as it almost exclusively feeds on the highly cyanogenic C. madagascariensis. Our data suggest that high HCNp is the derived state in bamboos. The ancestral state of lemurs is most likely generalist while the ancestral state of bamboo lemurs was determined as equivocal. Nevertheless, as recent bamboo lemurs comprise several facultative specialists and only one obligate specialist adaptive radiation due to increased flexibility is likely. We propose that escaping a strict food plant specialization enabled facultative specialist bamboo lemurs to inhabit diverse geographical areas

Revision of the genus Jumellea Schltr. (Orchidaceae) from the Comoros Archipelago

International audienceThe genus Jumellea Schltr. is revised for the Comoros Archipelago (Grande Comore, Anjouan, Mohéli, Mayotte). Six species occur on the islands: Jumellea anjouanensis (Finet) H. Perrier, J. arachnantha (Rchb. f.) Schltr., J. arborescens H. Perrier, J. comorensis (Rchb. f.) Schltr., J. maxillarioides and J. pailleri F.Rakotoar. These species are not the same as Schlechter covered; Jumellea arborescens, J. maxillarioides (Ridl.) Schltr. and J. pailleri were added to the list whereas Jumellea phalaenophora was removed since its presence in Comoros archipelago is doubtful. Jumellea gladiator (Rchb. f.) Schltr. is a synonym of J. arachnantha (Rchb.f.) Schltr. Three species of Jumellea are endemic to the Comoros archipelago whereas the three other are also present in Madagascar

Jumellea pailleri (Orchidaceae), une espèce nouvelle endémique des Comores

International audienceBackground and aims - Jumellea pailleri F.Rakotoar. (Orchidaceae), a new endemic species from the Comoro Archipelago is described and illustrated. Methods - Description and comparison of herbarium material from the herbarium of Comoro and Réunion Islands University (REU) have been done. Key results - Different from other Jumellea species from Comoro Island, J. pailleri resembles to J. bathiei Schltr. and J. ibityana Schltr., which are endemic to Madagascar. A key to identify Jumellea species from Comoro Islands is provided. The new species is illustrated, its distribution is given and its conservation status

Deux espèces de Jumellea nouvelles pour l’archipel des Comores

International audienceno abstrac

Molecular systematics and evolutionary trends and relationships in the genus Jumellea (Orchidaceae): Implications for its species limits

International audience\textlessI\textgreaterJumellea\textless/I\textgreater is an orchid genus centered on Madagascar but also occurs on some of the neighboring oceanic islands (the Mascarenes and Comoros) and in southern and eastern Africa. Prior to our study the genus contained ca. 55 morphologically distinct species, of which six are found in the Comoros (three endemic, three shared with Madagascar), nine in the Mascarenes (four endemic, four shared with Madagascar), two in southern and eastern Africa (both endemic), and 41 species endemic to Madagascar. We perform Bayesian and parsimony phylogenetic analyses of \textlessI\textgreaterJumellea\textless/I\textgreater based on combined chloroplast (\textlessI\textgreatermatK\textless/I\textgreater, \textlessI\textgreatertrnL-F\textless/I\textgreater, \textlessI\textgreaterrps16\textless/I\textgreater, \textlessI\textgreaterycf1\textless/I\textgreater) and nuclear (nrITS) data from 60 specimens representing 47 species, four subspecies, and two varieties of \textlessI\textgreaterJumellea\textless/I\textgreater: (1) to assess the phylogenetic value of growth form, leaf, bract and lip shape, and spur length, presently used for recognizing informal groups within the genus; and (2) to test the monophyly of some variable species (e.g., \textlessI\textgreaterJ. gracilipes\textless/I\textgreater, \textlessI\textgreaterJ. lignosa\textless/I\textgreater). We find no support for the informal groups of \textlessI\textgreaterJumellea\textless/I\textgreater, as all the characters tested are evolutionarily labile. \textlessI\textgreaterJumellea lignosa\textless/I\textgreater (comprising \textlessI\textgreaterJ. lignosa\textless/I\textgreater subsp. \textlessI\textgreaterlignosa\textless/I\textgreater, subsp. \textlessI\textgreatertenuibracteata\textless/I\textgreater, subsp. \textlessI\textgreateracutissima\textless/I\textgreater, and subsp. \textlessI\textgreaterlatilabia\textless/I\textgreater) is not monophyletic unless subsp. \textlessI\textgreatertenuibracteata\textless/I\textgreater is excluded. \textlessI\textgreaterJumellea gracilipes\textless/I\textgreater s. l. (including \textlessI\textgreaterJ. ambongensis\textless/I\textgreater, \textlessI\textgreaterJ. imerinensis\textless/I\textgreater, and \textlessI\textgreaterJ. unguicularis\textless/I\textgreater) is polyphyletic. As a result, we resurrect these three latter species, and recognize \textlessI\textgreaterJ. lignosa\textless/I\textgreater subsp. \textlessI\textgreatertenuibracteata\textless/I\textgreater at species level. Furthermore, we propose new circumscriptions for the following species: the Comorian \textlessI\textgreaterJ. arachnantha\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. sagittata\textless/I\textgreater); the Reunionese \textlessI\textgreaterJ. exilis\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. flavescens\textless/I\textgreater); the Reunionese \textlessI\textgreaterJ. recta\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJumellea\textless/I\textgreater sp. 1); the Reunionese \textlessI\textgreaterJ. recurva\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. pandurata\textless/I\textgreater); and the Reunionese \textlessI\textgreaterJ. stenophylla\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. gracilipes\textless/I\textgreater 2 and 3). Finally, \textlessI\textgreaterJumellea arborescens\textless/I\textgreater and \textlessI\textgreaterJ. maxillarioides\textless/I\textgreater are recorded from Madagascar and the Comoros. Finally, the number of species of \textlessI\textgreaterJumellea\textless/I\textgreater has now increased from 55 to 57: seven species in the Comoros (four shared with Madagascar), nine species in the Mascarenes (four shared with Madagascar), two species in Africa, and 39 species, three subspecies, and two varieties restricted to Madagascar

Différences morphologiques et identification de Jumellea rossii et Jumellea fragrans (Orchidaceae) à l’île de La Réunion : implications pour la conservation

Morphological differences and identification of Jumellea rossii and Jumellea fragrans (Orchidaceae) in Reunion Island : implications for conservation. — Conservation strategies are not possible when there is confusion in the taxonomic status of a group of plants. Such confusion makes difficult for systematic biologists to identify functional biological entities. This is particularly true in the case of species that diversified fast due to adaptive radiation particularly plants from the oceanic islands. It is the case of certain orchids from Reunion Island. Among them, the “Faham” complex includes several taxa whose populations are situated at various elevations with morphological and reproductive variations. These taxa are actually merged into one name : Jumellea fragrans causing confusion in their taxonomic status. This confusion has caused numerous problems of identification and errors hindering the protection status of the species. In this study, we suggest to clarify the systematic position of the taxa composing complex Jumellea fragrans using a biometric approach at population scale. The objective is to identify morphological characters that allow distinguishing the taxa of the J. fragrans complex. Morphological characters (vegetative and floral) are measured on individuals from three natural populations representative of altitudinal range of the complex. Principal component analysis made on the characters show a separation of the individuals in two groups (Mare-Longue vs Basse-Vallée and Cilaos). Nine characters (on 14 measured) are significantly different between Mare-Longue population and the populations of Basse-Vallée and Cilaos and allow identifying both groups. Population of Mare-Longue belongs to the species Jumellea fragrans (Thouars) Schltr. and populations of Basse-Vallée and Cilaos belongs to the species Jumellea rossii Senghas. In terms of conservation, the first recommendation is to recognize two different species : J. rossii and J. fragrans. Moreover, putting J. fragrans into the «vulnerable» IUCN Red List category and the adoption of a protection status are recommended. Concerning J. rossii, more studies on geographical range and population dynamics are necessary to estimate the risk of extinction. In the same way, studies on genetic variability of both species would generate useful data for implementation of conservation strategies.La clarification du statut taxinomique des espèces constitue un préambule nécessaire à la mise en place de mesures de conservation appropriées et efficaces, particulièrement dans les îles océaniques où la radiation adaptative rend difficile la reconnaissance des entités biologiques fonctionnelles. C’est le cas de certaines orchidées de La Réunion comme le «Faham» (Jumellea spp.) qui regroupe plusieurs taxons dont les populations se situent à différentes altitudes et semblent présenter des variations morphologiques et reproductives. Dans cette étude, nous proposons d’éclaircir la position systématique des taxons composant le complexe d’espèces regroupées sous le nom de «Faham» par le biais d’une approche morphométrique à l’échelle populationnelle et d’identifier des caractères morphologiques permettant de distinguer les différents taxons. Quatorze caractères (végétatifs et floraux) ont été mesurés sur 51 individus issus de trois populations naturelles représentatives de la distribution altitudinale du complexe. Des analyses multivariées effectuées sur ces caractères ont montré une séparation des individus en deux groupes (Mare-Longue d’une part, Basse-Vallée et Cilaos d’autre part). Neuf caractères sont significativement différents entre la population de Mare-Longue et les populations de Basse-Vallée et Cilaos et permettent de distinguer les deux groupes. La population de Mare-Longue appartiendrait à l’espèce Jumellea fragrans (Thouars) Schltr. et les populations de Basse-Vallée et Cilaos à l’espèce Jumellea rossii Senghas. En termes de conservation, la première recommandation est de reconnaître deux espèces bien distinctes : J. rossii et J. fragrans. D’autre part, l’inscription dans la catégorie «vulnérable» de la Liste Rouge de l’UICN et l’adoption d’un statut de protection semblent fortement recommandées pour J. fragrans. Concernant J. rossii, des connaissances approfondies sur la distribution géographique et la dynamique des populations de l’espèce s’avèrent nécessaires afin d’évaluer le risque d’extinction. Parallèlement, l’étude de la diversité génétique des deux espèces fournirait des données utiles pour la mise en oeuvre de plans de conservation.Mallet Bertrand, Humeau Laurence, Blambert Laury, Rakotoarivelo Fanny, Baider Cláudia, Pailler Thierry. Différences morphologiques et identification de Jumellea rossii et Jumellea fragrans (Orchidaceae) à l’île de La Réunion : implications pour la conservation. In: Revue d'Écologie (La Terre et La Vie), supplément n°11, 2012. Conférence sur la Conservation de la flore menacée de l’Outre-mer français. pp. 73-83

Lemur species and gene fragments included in the phylogenetic study, with family and GenBank accession numbers.

<p>Gene fragments: PAST, Pastorini fragment covering NADH3, NADH4L, NDH4 and 5 tRNAs; 12s rRNA; cyt-b, cytochrome; COII, cytochrome c oxidase subunit II; D-loop.</p

Lemur's degree of specialization towards bamboo plants traces on the phylogeny of lemurs, as inferred from a five gene fragments analysis.

<p>Possible states were "generalist" (either obligate of facultative), "facultative specialist" meaning that bamboo is the major food plant but other plants are also regularly consumed in nature and "obligate specialist" meaning that bamboo is the sole food plant accounting for more than 95% of the lemur's diet.</p

Bamboo species and specimens included in the phylogenetic study, with GenBank accession numbers.

<p>All ingroup taxa belong to the tribe Bambuseae (woody bamboos) and subtribes are given. Sequences generated in this study are indicated in bold.</p