Conservation of oceanic island floras: Present and future global challenges

Currentthreatstotheplanet’sbiodiversityareunprecedented,andtheyparticularlyimperilinsular floras.Inthisinvestigation,weusethethreatfactorsidentifiedbytheMillenniumEcosystem Assessmentasthemaindriversofbiodiversitylossonislandstodefineandrank13current,continuing threatstotheplantdiversityofninefocalarchipelagoswherevolcanicorigin(orintheSeychellesa prolongedisolationafteracontinentalorigin)hasproducedahighdegreeofendemicityandfragilityin the faceofhabitatalteration.Wealsoconductaglobalendangermentassessmentbasedonthe numbersofinsularendemicplantsintheendangered(EN)andcriticallyendangered(CR)IUCN categoriesfor53islandgroupswithanestimated9951endemicplantspecies,providinga representativesampleoftheworld’sinsularsystemsandtheirfloristicrichness.Ouranalysesindicate that isolationdoesnotsignificantlyinfluenceendangerment,butplantendemicsfromverysmall islandsaremoreoftencriticallyendangered.Weestimatethatbetween3500and6800oftheestimated 70,000 insularendemicplantspeciesworldwidemightbehighlythreatened(CR+EN)andbetweenca. 2000 and2800ofthemincriticaldangerofextinction(CR).Basedontheseanalyses,andona worldwideliteraturereviewofthebiologicalthreatfactorsconsidered,weidentifychallenging questionsforconservationresearch,asking(i)whatarethemosturgentprioritiesfortheconservation of insularspeciesandfloras,and(ii)withtheknowledgeandassetsavailable,howcanweimprovethe impactofconservationscienceandpracticeonthepreservationofislandbiodiversity?Ouranalysis indicatesthatthesynergisticactionofmanythreatfactorscaninducemajorecologicaldisturbances, leadingtomultipleextinctions.Wereviewweaknessesandstrengthsinconservationresearchand managementintheninefocalarchipelagos,andhighlighttheurgentneedforconservationscientiststo shareknowledgeandexpertise,identifyanddiscusscommonchallenges,andformulatemulti- disciplinaryconservationobjectivesforinsularplantendemicsworldwide.Toourknowledge,thisisthe mostup-to-dateandcomprehensivesurveyyettoreviewthethreatfactorstonativeplantsonoceanic islandsanddefinepriorityresearchquestions

A review of the dodo and its ecosystem: insights from a vertebrate concentration Lagerstätte in Mauritius

The dodo Raphus cucullatus Linnaeus,1758, an extinct and flightless, giant pigeon endemic to Mauritius, has fascinated people since its discovery, yet has remained surprisingly poorly known. Until the mid-19th century, almost all that was known about the dodo was based on illustrations and written accounts by 17th century mariners, often of questionable accuracy. Furthermore, only a few fragmentary remains of dodos collected prior to the bird's extinction exist. Our understanding of the dodo's anatomy was substantially enhanced by the discovery in 1865 of subfossil bones in a marsh called the Mare aux Songes, situated in southeastern Mauritius. However, no contextual information was recorded during early excavation efforts, and the majority of excavated material comprised larger dodo bones, almost all of which were unassociated. Here we present a modern interdisciplinary analysis of the Mare aux Songes, a 4200-year-old multitaxic vertebrate concentration Lagerstätte. Our analysis of the deposits at this site provides the first detailed overview of the ecosystem inhabited by the dodo. The interplay of climatic and geological conditions led to the exceptional preservation of the animal and associated plant remains at the Mare aux Songes and provides a window into the past ecosystem of Mauritius. This interdisciplinary research approach provides an ecological framework for the dodo, complementing insights on its anatomy derived from the only associated dodo skeletons known, both of which were collected by Etienne Thirioux and are the primary subject of this memoir.Additional co-authors: Anneke H. Van Heteren, Vikash Rupear, Gorah Beebeejaun, Alan Grihault, J. (Hans) Van Der Plicht, Marijke Besselink, Juliën K. Lubeek, Max Jansen, Hege Hollund, Beth Shapiro, Matthew Collins, Mike Buckley, Ranjith M. Jayasena, Nicolas Porch, Rene Floore, Frans Bunnik, Andrew Biedlingmaier, Jennifer Leavitt, Gregory Monfette, Anna Kimelblatt, Adrienne Randall, Pieter Floore & Leon P. A. M. Claessen

Syzygium (Myrtaceae): Monographing a taxonomic giant via 22 coordinated regional revisions

Syzygium Gaertn. is the largest woody genus of flowering plants in the world. Unpublished but extensive recent herbarium surveys suggest 1200‒1800 species distributed throughout the Old-World tropics and subtropics (Table 1). Until recently, Syzygium exemplified a recurring taxonomic impediment among megadiverse genera, wherein few taxonomists worked on the group in any sustained manner, a majority of the herbarium specimens remained undetermined or misidentified, few if any attempts were made to look at the genus globally and limited or no molecular studies were available to provide a predictive phylogenetic context of the genus. The situation with Syzygium has slowly begun to change as allied genera have been absorbed into the genus (Biffin et al., 2006; Craven & Biffin, 2010), and predictive phylogenetically based infrageneric classifications are emerging. Taxonomic outputs on Syzygium also have been increasing across its range with the description of new species, resolution of nomenclatural and typification issues, and some regional revisions being initiated or updated. However, virtually all regional treatments (which some areas lack) need urgent revision because they are severely outdated, have limited molecular sampling and are error-ridden. We are coordinating a genus-wide taxonomic update of Syzygium through a series of 22 regional revisions, including 9 in the Flora Malesiana region (Figure 1). Each treatment will include a phylogenetic framework with species descriptions, type information, synonymy, distributions, ecological notes, and keys. Field images (Figure 2) and/or line drawings will be included with the goal of every species being illustrated. This working group has been formed to encourage a coordinated effort to document this unwieldy taxonomic giant and regional botanists working on the group are encouraged to be involved. A robust taxonomy of the genus is a prerequisite for testing the many complex questions about evolution and ecology that Syzygium could help address

Syzygium pyneei (Myrtaceae), a new critically endangered endemic species from Mauritius.

A new species of Syzygium Gaertn. (Myrtaceae), S. pyneei Byng, V. Florens & Baider, is described from Mondrain Reserve on the island of Mauritius. This species is endemic to the island and differs from any other species by its combination of cauliflory, relatively large flowers, light green to cream hypanthium, light pink stamens, short thick petioles, coriaceous leaves and round, cuneate or sub-cordate to cordate leaf bases. Syzygium pyneei Byng, V. Florens & Baider is known from only two individuals from the type locality and merits the conservation status of Critically Endangered (CR C2a(i,ii); D)

Two new records of Jumellea (Orchidaceae) for Mauritius (Mascarene Islands) and their conservation status

International audienceTwo new records of Jumellea for the island of Mauritius (Indian Ocean), J. exilis and J. rossii are reported from incorrectly attributed past collections. Sampling over the last four decades on Mauritius recorded only a few localities for J. exilis, while J. rossii is known from only a single collection. Recent surveys confirm that J. exilis is very rare, qualifying as Critically Endangered on Mauritius according to the IUCN Red List Criteria, and J. rossii should be considered as probably Extinct. An updated key to the Jumellea of Mauritius is provided. Threats besetting the species and other orchids in general in Mauritius are discussed and conservation measures suggested

Surviving 370 years of human impact: what remains of tree diversity and structure of the lowland wet forests of oceanic island Mauritius?

International audienceMauritius, a 1,865 km2 oceanic island within the Madagascar and Indian Ocean islands biodiversity hotspot may be regarded as reflecting what awaits many tropical oceanic islands owing to the extreme levels of transformation resulting from over 370 years of human presence. The island has an urgent need to conserve its surviving remnants of native terrestrial habitats. There, however, exists little published quantitative information like species diversity, stem density and basal area in these habitats and other essential parameters for informing their conservation. We surveyed woody native plants in five of the best preserved lowland wet forests using 75 random plots of 100 m2 (totalling 0.75 ha). Density, dominance and frequency values were calculated along with species and family importance values for each site. For plants ≥1 cm diameter at breast height, 108 species in 66 genera and 39 families were represented by 6,000 individual plants. This gives a density of 8,000 plants per ha which is very high for a lowland wet tropical forest. Species endemism within the plots was 63 % to Mauritius and 87 % to the Mascarenes. Some 56 % of all woody native species ever recorded from the lowland wet forest of Mauritius was sampled. Extrapolated basal area varied from 31 to 49.1 m2 per ha. The mean similarity in species between pairs of sites was about 60 %. Mauritian wet forests retain the highest tree diversity in the Mascarenes, and probably among all isolated oceanic islands around the world despite massive habitat destruction, extraction and invasion by alien species. Substantial conservation importance and restoration potential still exist

Invasive alien plants progress to dominate protected and best-preserved wet forests of an oceanic island

International audienceInvasive alien plants pose a threat to biodiversity in particular on oceanic islands, where endemism tends to be high. In this context, it matters to characterise invasions in-situ and in particular to document how far invasive plants may invade protected areas devoid of major human disturbances. We explore this question on the tropical island of Mauritius, which provides an interesting case study because it possesses several attributes of human impacts, which are increasingly being encountered by most tropical oceanic islands worldwide. Mauritius today may thus serve as a “window” into the future of many other islands. We assess woody invasive alien plant abundance in the island’s wet native forests by sampling five of the currently best-preserved sites. We chose only protected areas that have benefitted from long-term legal protection. All woody alien plants reaching at least 1 cm of diameter at breast height (dbh) were identified and their dbh measured in a series of fifteen 100 m2 quadrats randomly placed in each forest. All sites are today dominated by woody invasive alien plants, which comprised 78.5% of the 27 868 sampled plants ≥1 cm dbh. Density-wise, the alien shade tolerant strawberry guava (Psidium cattleianum) dominates all forests sampled. In terms of Importance Value (as percent relative dominance and percent relative density), P. cattleianum dominates four sites and another alien, Cinnamomum verum, dominates one site. Our study shows that even though relatively diverse, the native plant communities of an oceanic island cannot resist the encroachment of understory invasive alien plants, even in better preserved, least disturbed forests that have been receiving long-term formal legal protection

Drivers of wetland disturbance and biodiversity impacts on a tropical oceanic island

Wetlands are biologically important elements of landscapes and among the most threatened ecosystems on Earth. On the island of Mauritius, many remaining wetlands are being rapidly converted and fragmented by intense land-use demands. We surveyed 209 coastal wetlands on Mauritius to assess their biophysical attributes, land-use activities, and patterns of disturbance, to help identify factors that threaten wetland biodiversity. Most wetlands exhibited severe edge-related disturbances and more than half were fragmented. Plant species richness was highest in larger, unfragmented wetlands and lower in wetlands with degraded margins. Urban wetlands were smaller and more likely to be fragmented than those adjoining other land uses such as grazing and agriculture. Flooding of urban homes and infrastructure was more likely to occur near fragmented than natural wetlands. Ongoing wetland decline in Mauritius not only contributes to the loss of local biodiversity but reduces the larger ecosystem role these habitats play in regulating surface water and protecting adjacent marine habitats. © 2011 Elsevier Ltd. All rights reserved

Isolation and Characterization of Microsatellite Markers for Mimusops balata (Sapotaceae) and Cross-Amplification in Other Mimusops Species

Mimusops balata (Sapotaceae) is an endemic tree species from La Réunion and Mauritius. Like many species growing in lowland forests in La Réunion, it has suffered from human disturbances. We developed twelve microsatellite markers for M. balata and tested cross-amplification in five other Mimusops species to have powerful tools for genetic diversity studies. Genotyping peaks were of very low quality for two loci and were consequently abandoned for the genetic diversity analyses. Ten microsatellite loci were tested on 34 individuals of M. balata from two natural populations. The number of alleles per locus ranged from one to seven. The observed and expected heterozygosity levels varied from 0.000 to 0.823, and from 0.000 to 0.812 respectively. Two loci deviated from the Hardy-Weinberg equilibrium. The presence of null alleles was detected for one of these two loci. Nine to ten loci cross-amplified reliably in Mauritian species, for the other three species, four to six loci show successful amplifications. These polymorphic microsatellite markers are now available for population genetic investigations in Mimusops species aiming to establish accurate guidelines for conservation managers

Plant trnL references and beetle derived variants

A fasta file of plant sequences amplified for this paper. Sequences are not aligned globally but beetle variants are aligned to each plant reference. The description section of each fasta sequence explains whether a beetle derived sequence was identified by comparison to a reference sequence or using SAP