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Notes sur la disparition d’une espèce emblématique : Robinsonia berteroi (DC.) Sanders, Stuessy & Martic. (Asteraceae), dans l’île Robinson Crusoe, archipel Juan Fernández (Chili).

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Abstract

Suite à la disparition de Robinsonia berteroi (DC.) Sanders, Stuessy & Martic. (Asteraceae) dans l'île Robinson Crusoe, Archipel Juan Fernández (Chili), au mois d’août 2004, une description de cette espèce emblématique et les causes de sa disparition sont présentées. La liste des espèces disparues (Cat. UICN : Ex) et des espèces au bord de l'extinction (Cat. UICN : Cr) de ces îles est indiquée afin d’attirer l’attention sur les nécessaires et urgentes mesures de préservation et conservation qui restent à prendre dans l’archipel.
... Sanders, Stuessy & Martic. and R. macrocephala Decne., could not be collected, because they are now regarded as extinct (Danton & Perrier, 2005;Ricci, 2006;Danton et al., 2006). Leaves of R. evenia Phil., R. gayana Decne., R. gracilis Decne., R. saxatilis Danton, R. thurifera Decne. ...
... The new data from AFLP and microsatellite (SSR) analyses (Figs 2, 3) correlate well with those obtained previously from morphology (Skottsberg, 1922;Sanders et al., 1987), flavonoids (Pacheco et al., 1985), isozymes , restriction site analyses (Crawford et al., 1993) and ITS sequences (Sang et al., 1995). Robinsonia berteroi and R. macrocephala on Robinson Crusoe could not be included in the present study, because they are now regarded as extinct (Danton & Perrier, 2005;Danton et al., 2006;Ricci, 2006). Genetic differentiation among species with these population markers is clear, suggesting high levels of reproductive isolation. ...
Article
This study analyses and compares the genetic signatures of anagenetic and cladogenetic speciation in six species of the genus Robinsonia (Asteraceae, Senecioneae), endemic to the Juan Fernández Islands, Chile.Population genetic structure was analyzed by amplified fragment length polymorphism (AFLP) and microsatellite (simple sequence repeat, SSR) markers from 286 and 320 individuals, respectively, in 28 populations. Each species is genetically distinct. Previous hypotheses of classification among these species into subgenera and sections, via morphological, phytochemical, isozymic and internal transcribed spacer (ITS) data, have been confirmed, except that R. saxatilis appears to be related to R. gayana rather than R. evenia.Analysis of phylogenetic results and biogeographic context suggests that five of these species have originated by cladogenesis and adaptive radiation on the older Robinson Crusoe Island. The sixth species, R. masafuerae, restricted to the younger Alejandro Selkirk Island, is closely related to and an anagenetic derivative of R. evenia from Robinson Crusoe.Microsatellite and AFLP data reveal considerable genetic variation among the cladogenetically derived species of Robinsonia, but within each the genetic variation is lower, highlighting presumptive genetic isolation and rapid radiation. The anagenetically derived R. masafuerae harbors a level of genetic variation similar to that of its progenitor, R. evenia. This is the first direct comparison of the genetic consequences of anagenetic and cladogenetic speciation in plants of an oceanic archipelago.
... Robinsonia macrocephala. And on August 2004 we have been testified of the extinction of the last exemplar of Robinsonia berteroi (Danton & Perrier, 2005). The threats follow a clear direction, being today more that 27 species in critical endangered status. ...
... The threats follow a clear direction, being today more that 27 species in critical endangered status. Eight correspond to Asteraceae from the genera Centaurodendron (1), Dendroseris (5), Erigeron (1), and Yunquea (1) (Danton & Perrier, 2005). Back to the mainland, conservation research steadily suggests the need of improvement of the protected areas system in central Chile (Muñoz Pizarro, 1973; Muñoz-Schick et al., 1996; Arroyo et al., 2002; Pliscoff, 2003). ...
Article
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This paper provides a synopsis of the Chilean Asteraceae genera according to the most recent classification. Asteraceae is the richest family within the native Chilean flora, with a total of 121 genera and c. 863 species, currently classified in 18 tribes. The genera are distributed along the whole latitudinal gradient in Chile, with a centre of richness at 33°–34° S. Almost one-third of the genera show small to medium-small ranges of distribution, while two-thirds have medium-large to large latitudinal ranges of distribution. Of the 115 mainland genera, 46% have their main distribution in the central Mediterranean zone between 27°–37° S. Also of the mainland genera, 53% occupy both coastal and Andean environments, while 33% can be considered as strictly Andean and 20% as strictly coastal genera. The biogeographical analysis of relationships allows the distinction of several floristic elements and generalized tracks: the most marked floristic element is the Neotropical, followed by the antitropical and the endemic element. The biogeographical analysis provides important insights into the origin and evolution of the Chilean Asteraceae flora. The presence of many localized and endemic taxa has direct conservation implications.
... Although these species occur either on high ridges or in deep forests, far removed from most persons who live at sea level in the village (San Juan Bautista), incursions into the native forest must have taken place and some plants destroyed. It is known that two species of Robinsonia, both on Robinson Crusoe Island, are now extinct (R. berteroi and R. megacephala; Danton and Perrier 2005;Danton et al. 2006). Assessing the level of human impact on the vegetation of an oceanic island, therefore, is challenging. ...
Article
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Adaptive radiation is a common mode of speciation among plants endemic to oceanic islands. This pattern is one of cladogenesis, or splitting of the founder population, into diverse lineages in divergent habitats. In contrast, endemic species have also evolved primarily by simple transformations from progenitors in source regions. This is anagenesis, whereby the founding population changes genetically and morphologically over time primarily through mutation and recombination. Gene flow among populations is maintained in a homogeneous environment with no splitting events. Genetic consequences of these modes of speciation have been examined in the Juan Fernández archipelago, which contains two principal islands of differing geological ages. This paper summarizes population genetic results (nearly 4,000 analyses) from examination of 15 endemic species, involving 1,716 and 1,870 individuals in 162 and 163 populations (with AFLPs and SSRs, respectively) in the following genera: Drimys (Winteraceae); Myrceugenia (Myrtaceae); Rhaphithamnus (Verbenaceae); Robinsonia (Asteraceae, Senecioneae); Erigeron (Asteraceae, Astereae). The results indicate that species originating anagenetically show high levels of genetic variation within the island population and no geographic genetic partitioning. This contrasts with cladogenetic species that show less genetic diversity within and among populations. Species that have been derived anagenetically on the younger island (1-2 Ma) contain less genetic variation than those that have anagenetically speciated on the older island (4 Ma). Genetic distinctness among cladogenetically derived species on the older island is greater than among similarly derived species on the younger island. An important point is that the total genetic variation within each genus analyzed is comparable, regardless of whether adaptive divergence occurs. Published by Oxford University Press on behalf of the Annals of Botany Company.
... Fuegos, cortas selectivas de árboles y la introducción de especies exóticas de animales y plantas afec-taron enormemente la cobertura vegetal de las tres islas en el pasado. En la actualidad más del 75% de la flora endémica del Archipiélago se encuentra en grave peligro de extinción (Cuevas y van Leersum 2001) (Figura 6.3), existiendo ocho especies extintas recientemente, como Santalum fernandezianum en 1913, o Robinsonia berteroi en 2004 (Danton & Perrier 2005CONAF 2009). Dos de las cuatro especies de aves listadas en Peligro Crítico de Conservación para Chile, ocurren exclusivamente en una isla del Archipiélago Juan Fernández: el picaflor de Juan Fernández (Sephenoides fernandensis) en Robinson Crusoe, y el rayadito de Masafuera (Aphrastura masafuerae) en Alejandro Selkirk (Rau 2006). ...
... Today at least 75% of the endemic flora is highly threatened (Swenson et al. 1997; Cuevas and van Leersum 2001). Danton and Perrier (2005Perrier ( , 2006) listed eight species that went extinct (EX) in historical times, mostly during the last decades: Podophorus bromoides, Santalum fernandezianum, Chenopodium nesodendron , Empetrum rubrum, Eryngium sarcophyllum, Notanthera heterophylla, ...
Article
Conservation biogeography meets many challenges around the world associated with increasing human pressure on ecosystems and processes like global change. Threats as well as conservation opportunities are differentially distributed over the Chilean territory, and are here explored in relation to modern approaches such as systematic conservation planning.
... Nevertheless, this seems to be sadly not the case for the Fernandezian endemic composites since the islands' flora is the most endangered of the country and one of the most threatened island territories worldwide (see Chap 5). This directly affects several Asteraceae species: two species, Robinsonia berteroi and R. macrocephala are already extinct (Danton and Perrier 2005), while ca. 30 species (i.e. ...
Article
Being the richest family worldwide, the Asteraceae is also the richest Chilean family at the genus and species level. According to the most up to date knowledge, it encompasses 123 genera and 838 native species, that pertain to 20 different tribes. The 123 genera have been classified in 7 floristic elements and 9 generalized tracks and the geographical evolution of the family is discussed. Analysis of endemism has been undertaken by means of the program NDM/VNDM, resulting in 6 areas of endemism, some of them overlapping in Central Chile. Finally, several aspects about the conservation of the Chilean Asteraceae are discussed, considering also the high degree of alien invasive taxa and the gaps in the distributional knowledge. An exercise towards bridging these gaps is undertaken by means of niche modeling of Mutisia species.
... Sanders et al. (1987) considered the differences between Rhetinodendron and Robinsonia to be insufficient to maintain both genera as separate taxa, and combined them in Robinsonia sensu lato (Pacheco et al. 1985). Unfortunately, Robinsonia berteroi is believed to have gone extinct in 2004 (Danton & Perrier 2005). ...
Article
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Robinsonia is a genus of eight species and is endemic to the Juan Fernandez Islands. Previous studies based on ITS phylogenies place Robinsonia deeply nested within Senecio, however its monophyly remains uncertain. In this paper, we use phylogenies reconstructed from plastid, ITS-ETS, and combined data to test its monophyly. Plastid phylogenies support Robinsonia as monophyletic, whereas ITS-ETS trees suggest that Robinsonia berteroi may be more closely related to a South American clade of Senecio species rather than to the remaining Robinsonia species. Maximum parsimony and Bayesian inference analyses of the combined data are congruent with the plastid trees, whereas maximum likelihood analyses are congruent with the ITS-ETS data. Nodal support for either hypothesis is generally low, and Shimodaira-Hasegawa tests in which Robinsonia was either constrained to be monophyletic or to be non-monophyletic showed that these trees do not have significantly lower likelihood scores than trees from unconstrained analyses. Thus the monophyly of Robinsonia remains inconclusive despite additional data and analyses. The results of the present paper further corroborate the results of previous studies that Robinsonia is deeply nested within Senecio. We therefore propose to reduce Robinsonia to synonymy and present new names and combinations of the Robinsonia species under Senecio.
Thesis
Historical biogeography has seen a rapid theoretical and methodological developed in the last decades. Concepts such as dispersal, vicariance, or panbiogeography show a constant synergy in the renewal of the theory and the praxis. The present thesis examines the most important phytogeographical issues in Chile with special consideration of the distribution and geographical relationships of the genera. The consequences of these relations on the evolution of the Chilean Flora are discussed thereby, particularly under different possible palaeogeographical scenarios. In addition the conditions in the context of the modern and postmodern science theory are considered. This permits a context-oriented synthesis of the Chilean plant geography, that set the starting point for further research in this crucial field between geography and biology.
Article
Full-text available
As vegetative architecture and its main concepts (sequential branching, architectural models, reiteration) were born in the humid tropics, a long term study of the Juan Fernández flora and vegetation provided an opportunity to test whether or not those concepts remain valid in quite a different sort of environment. Robinson Crusoe is an isolated island of the South Pacific, at 33° South, having an oceanic temperate climate, a rough topography and a rich highly endemic flora. Through the architectural analysis of more than 50 species of ferns and seed-plants, it is established that, not only are the architectural concepts still valid, but that the 12 architectural models actually recorded are identical to those found elsewhere on mainlands, even if their taxonomic distribution differs. The reiteration ability is unevenly distributed: rare or absent in most of the endemics, it is extremely developed in the “pests” introduced from the mainland, Maqui, Zarzamora and Murtilla. It is shown that such a big difference in reiteration ability is likely to explain the threat that “pests” pose on endemics. The only possibility left to save the endemic flora seems to be the creation of a botanical garden on Robinson Crusoe Island.
Article
The study of island biotas has been one of the most productive issues in biogeography. Indeed, one of the most interesting and challenging aspects of Chilean plant geography correspond to the Pacific islands offshore the American continent. This applies especially for the Juan Fernández and the Islas Desventuradas archipelagos that are analyzed regarding their geographical relationships. The flora of Juan Fernández is especially attractive for biogeography due to the presence of many locally endemic taxa, and a primitive endemic family: the Lactoridaceae, represented by the only species Lactoris fernandeziana. Finally, the threatened status of most of the Fernandezian flora is discussed with attention for the possibilities of conservation and restoration.
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