Lindsay Chong-Seng's scientific contributions
Cryptic diversity corresponding with island of origin has been previously reported in the endemic, geographically restricted sooglossid frogs of the Seychelles archipelago. The evolutionary pattern behind this has not been fully explored, and given current amphibian declines and the increased extinction risk faced by island species, we sought to identify evolutionarily significant units (ESUs) to address conservation concerns for these highly threatened anurans. We obtained genetic data for two mitochondrial (mtDNA) and four nuclear (nuDNA) genes from all known populations of sooglossid frog (on the islands of Mahé, Praslin and Silhouette) for phylogenetic analyses and to construct nuDNA haplotype networks. Bayesian and maximum likelihood analyses of mtDNA support the monophyly and molecular differentiation of populations in all species that occur on multiple islands. Haplotype networks using statistical parsimony revealed multiple high-frequency haplotypes shared between islands and taxa, in addition to numerous geographically distinct (island-specific) haplotypes for each species. We consider each island-specific population of sooglossid frog as an ESU and advise conservation managers to do likewise. Furthermore, our results identify each island lineage as a candidate species, evidence for which is supported by analyses of mtDNA based on Bayesian Poisson tree processes, and independent analyses of mtDNA and nuDNA using the multispecies coalescent. Our findings add to the growing understanding of the biogeography and hidden diversity within this globally important region. ADDITIONAL KEYWORDS: candidate species-cryptic diversity-evolutionarily significant unit-Indian Ocean-insular amphibians-islands-Sechellophryne-Seychelles-Sooglossidae-Sooglossus.
We created a project "Seychelles Bio Gallery" in iNaturalist to allow people of Seychelles to contribute observations of organisms from nature in a way that stimulate interaction and communication between scientists and civil society, and in a way that valuable observation made on rare species (obscured coordinates) can be downloaded by the local scientific community.
Based on a review of recent literature on CMP best practice (Alexander 2013) and extensive discussions with stakeholders and especially ICS, we suggest that the key aspects for a CMP to be adaptive (working document) and to better assess efficiency and implementation are: • The definition of a clear and simple conceptual framework, or in other words a simple structure to organize the information • To store and to share CMP information in a relational database format rather than a text document format • To record actions and results by linking those to the planned element of the relational CMP database A clear and simple structure to organize the CMP information is essential. In many traditional formats of CMP, the structure is characterized by a large number of sections and subsections and the overwhelming complexity of a many-level hierarchy in the table of content makes the implementation difficult and managers struggle to take appropriate actions in line with clear objectives. The conceptual framework proposed here is based on the principle that all CMP information can be grouped in one of the four categories: Features, Factors, Projects and Actors. Features are defined as ultimate conservation targets (e.g. Sheath-Tailed Bat) while factors are things that we can act upon in order to get an indirect effect on features (e.g. rat control, but also financial planning, infrastructures, etc.). Detailed ‘evaluation’ of conservation features and prioritization is therefore not anymore treated as a distinct chapter of the CMP but rather as one of the projects (knowledge development and CMP review). Secondly, a CMP needs to be pragmatic and detailed with respect to specific actions and methods, linked to ecologically meaningfull objectives. As we get to that level of details, the amount of CMP information to organize becomes rapidly incompatible with the concept of a short, simple text. Therefore, the best option to easily explore the details relative to conservation ‘Projects’ consists in managing the information not in the form of a linear text but rather in the form of an ‘interactive database format’. Thirdly, the great advantage of managing CMP information in an interactive database format is that it also allows to explicitely link planned actions or targeted objectives to recording of actions actually done or results actually obtained. As a result, it is possible to generate monthly and annual report much more easily, and it is possible to assess in real time the level of implementation and efficiency of a CMP, and therefore to identify more easily needs for changes or review of the CMP. Therefore the proposed Silhouette Adaptive Conservation Management Plan consists in the database file accompanying the present report. The report itself is only an accompanying document to introduce the database and describes the approach and the main content elements at present. To explore the CMP, open the database file “BioCoMa.accdb”; in the ‘Main Menu’, select a project from the list and click the button to see the related actions and objectives (see Figure B). Proposed ‘Vision’ compiled from stakeholders’ input The unique and remarkably well preserved ecosystems of Silhouette are maintained (in natural areas) or recovering (in semi-natural areas), with a growing ratio of native over exotic species and with a special attention to globally threatened species (IUCN Red List). The only known Sheath-Tailed Bat population of La Passe remains stable or increases, and new explorations are progressively covering most of the island in search of other roosts. Other conservation flagship species such as turtles, giant tortoises, birds, and commercial species (octopus, fishes, etc.) are monitored without interruption and remain at favorable conservation state. The number of invasive species is stabilized or reduced in natural ecosystems and pests are controlled in the inhabited areas, reducing the threat on native species and ecosystems. Silhouette biota (species and ecosystem) provide original material for training of pairs of young Seychellois and overseas researchers or students. Collaboration programs are operating with various worldwide scientific teams and organizations and papers are published every year with Seychellois partners, contributing to improvement of our knowledge on biodiversity and evolution. Leading stakeholders involved in Silhouette Island conservation management have the required capacities to perform their duties, hand over phases are adapted to the typical small island rapid staff turnover, and training are done annually to consolidate or further develop staff capacities. The Adaptive Conservation Management Plans are regularly reviewed at SF meeting and up-to-date plans are accessible to stakeholders who can suggest modifications of plans or provide information on activities done or results to be recorded. The CMP system also allows for detailed monitoring of management efficiency and features' conservation state. Stakeholders' relations are cared for and visitors have access to a high quality service so to discover or enjoy safely and sustainably the unique environment of Silhouette Island, contributing to sustainable economic development and supporting conservation programs.
Feral goats Capra hircus, considered among the world’s most destructive invasive mammals, were introduced to Aldabra Atoll, a UNESCO World Heritage site in the Seychelles, before 1878. An eradication programme to remove goats from Aldabra was initiated in 1987, after severe ecological impacts were recorded. Eradication and control efforts continued intermittently for the next 20 years, and a final campaign was launched in 2007 using the Judas goat method. We present the methods, eradication dynamics, outcomes and financial costs of the final eradication campaign between 2007 and 2012. This effort was divided into three phases; (1) establishment of Judas goats and intensive hunting (4 months); (2) monitoring of Judas goats (4 years); and (3) Judas goat elimination and verification of success (8 months). In the focal 5-year period, 227 goats were culled (of 2297 across the entire 25-year period); 202 in phase 1, 21 in phase 2, and four remaining Judas goats in phase 3. The eradication was completed and confirmed successful in August 2012, following the use of multiple measures to confirm the absence of goats. The total cost of the eradication was US$ 185,105, an average of US$ 815/goat, or US$ 31/ha. The eradication, although ultimately successful, posed a unique combination of challenges. We discuss key lessons learned and put the project in context of other major island goat eradications. The financial details, context and lessons are expected to be of value to future practitioners.
To assess the conservation value and the rehabilitation potential of the forests in the Mare aux Cochons water catchment, we compiled all historical records from specimens and literature (using the 'KBA database') and we made new field observations based on plot-less explorations focussing on species of special conservation value (KBA species) and invasive species. To assess quantitatively the forest structure and population structure with regards to the main canopy invasive trees, we also established 7 nested plots, each made of 3 sub-plots to cover the main strata (canopy, under-canopy, and understorey). The most critical areas for conservation include small refugia found in the submontane valleys of the three main rivers, accommodating the following species: Asplenium petiolulatum (previously known from 1 specimen in Seychelles), Antrophyum immersum (last seen on Mahé in 1870s), Vateriopsis seychellarum (possibly the second best population discovered), Oeceoclades pulchra (known from 1 individual on Mahé). Other important sites for conservation include montane swamps (mostly La Drisse), montane valleys (mostly slopes above La Drisse), montane saxicolous habitats (Mont Jasmin and Glacis Sarcelles) and montane mesic forests (the upper edges of the Mare aux Cochons watershed area, which are in their best conservation state on Mont Jasmin). The slopes above La Drisse possibly hold the second best population in Seychelles for the critically endangered endemic tree Drypetes riseleyi. Among the 47 exotic species recorded, we considered 22 of them to be 'invasive' species, of which 5 have been prioritized for control actions. The canopy trees Pentadesma butyracea and Sandoricum koetjape are still relatively localized within the study area and represent a good opportunity to develop forest rehabilitation methods (as long term projects). The other three species prioritized for control actions (Coffea canephora, Dieffenbachia seguine and Ardisia crenata) are all understorey plants and therefore their control can be developed in the shorter term, since interventions do not require management of canopy issues. Other highly invasive species (such as Cinnamomum verum, Psidium cattleianum, Syzygium jambos, and Falcataria moluccana) also need to be addressed but control actions seem to be of lower priority (at least from a biodiversity perspective) considering that they already have a widespread distribution. From a water catchment perspective, prioritizing the control of the fast growing Falcataria moluccana remains a debatable subject which requires specialized studies to clearly establish the impact of that species on water resources. Falcataria moluccana does not regenerate in the forest understorey and needs canopy gaps to successfully establish itself. This means that taking care of the current canopy gaps is an important aspect to consider, and ring barking of Falcataria populations will have a negative impact if it ends up generating massive canopy openings. A site with a high priority for 'water catchment-oriented' forest rehabilitation (including dam construction) is the area surrounding the valley of the Rivière Cascade (outlet 3), and the depression found between Col de Vingt Cinq Sous and Mare aux Cochons Ramsar site (outlet 1) (Figure 8b). In the La Drisse area, we recommend more 'biodiversity-oriented' rehabilitation approaches including the removal of exotic species and the planting of some critically endangered species selected on the bases of their particular ecology. Wetlands (swamp forests) and valley forests remain under-explored in the area, especially for the lowland and submontane belts. These types of habitats were mapped in a recent study (2014) and the maps have been validated with precision during the current collection of ground truthing data. We therefore recommend making full use of these maps.
The last comprehensive account on the Seychelles orchids dates from 1989, by Robertson, and was mostly based on literature synthesis. This document recorded 33 taxa: 21 natives and 12 introduced. The Seychelles orchids remain poorly studied and poorly collected. There is a need for more taxonomic studies, and more collections associated with cultivation in a nursery dedicated to the taxonomy of orchids. Here, we present a synthesis of the existing specimens (ca. 150) and sight records (ca.500) of Orchidaceae in the Seychelles and we analyze their distribution within ecological groups and biological types. We also present the most problematic taxa needing more careful study.
... The cryptic diversity we have uncovered indicates a total of eight independent island lineages that should be managed accordingly. Such management action should include regular long-term population and habitat assessments, support of the genetic integrity of each ESU by carrying out no inter- island translocations, and the establishment of regular screening activities for invasive pathogens including Batrachochytrium dendrobatidis, B. salamandrivorans and Ranavirus; notably, the Seychelles is one of only two global regions where pathogenic chytrids have yet to be detected ( Labisko et al, 2015;Lips, 2016). The identification of distinct, island-specific populations of these frogs warrants continued investigation of their intraspecific relationships, and further insights are likely to reveal additional factors important for their future conservation. ...
... Plot-less Rapid Inventories consist in recording all species within a given "stand" 1 for defined subset of the total flora. In this case, we focussed on recording all species of special conservation value ('KBA species: Senterre et al. 2011; Senterre & Henriette 2015) plus all invasive species. Plot-less Intensive Inventories consist in recording all species within a given stand regardless of the conservation value or invasiveness, but eventually filtering on taxonomic groups (e.g. ...
... To establish the list of species of special conservation value present in the two study sites, we first consulted the relatively recent synthesis of the 'KBA study' (Senterre et al. 2013) and then we completed with a review of more recent publications or reports (mostly specialised on wetlands or wetland species). We also checked the Seychelles Biodiversity Metadatabase (Senterre et al. 2010) to find any relevant publication or report for some species reported of expected in the studied wetlands. ...