Plants are a hyperdiverse clade that plays a key role in maintaining ecological and evolutionary processes as well as human livelihoods. Biases, gaps and uncertainties in plant occurrence information remain a central problem in ecology and conservation, but these limitations remain largely unassessed globally. In this synthesis, we propose a conceptual framework for analysing gaps in information coverage, information uncertainties and biases in these metrics along taxonomic, geographical and temporal dimensions, and apply it to all c. 370 000 species of land plants. To this end, we integrated 120 million point-occurrence records with independent databases on plant taxonomy, distributions and conservation status. We find that different data limitations are prevalent in each dimension. Different metrics of information coverage and uncertainty are largely uncorrelated, and reducing taxonomic, spatial or temporal uncertainty by filtering out records would usually come at great costs to coverage. In light of these multidimensional data limitations, we discuss prospects for global plant ecological and biogeographical research, monitoring and conservation and outline critical next steps towards more effective information usage and mobilisation. Our study provides an empirical baseline for evaluating and improving global floristic knowledge, along with a conceptual framework that can be applied to study other hyperdiverse clades.

Multidimensional biases, gaps and uncertainties in global plant occurrence information

Spatio‐temporal history of the endemic genera of Madagascar

Grasses, by their high productivity even under very low pCO2, their ability to survive repeated burning and to tolerate long dry seasons, have transformed the terrestrial biomes in the Neogene and Quaternary. The expansion of grasslands at the cost of biodiverse forest biomes in Madagascar is often postulated as a consequence of the Holocene settlement of the island by humans. However, we show that the Malagasy grass flora has many indications of being ancient with a long local evolutionary history, much predating the Holocene arrival of humans. First, the level of endemism in the Madagascar grass flora is well above the global average for large islands. Second, a survey of many of the more diverse areas indicates that there is a very high spatial and ecological turnover in the grass flora, indicating a high degree of niche specialization. We also find some evidence that there are both recently disturbed and natural stable grasslands: phylogenetic community assembly indicates that recently severely disturbed grasslands are phylogenetically clustered, whereas more undisturbed grasslands tend to be phylogenetically more evenly distributed. From this evidence, it is likely that grass communities existed in Madagascar long before human arrival and so were determined by climate, natural grazing and other natural factors. Humans introduced zebu cattle farming and increased fire frequency, and may have triggered an expansion of the grasslands. Grasses probably played the same role in the modification of the Malagasy environments as elsewhere in the tropics.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2015.2262

Madagascar's grasses and grasslands:anthropogenic or natural?

Phylogeographic analysis can be described as the study of the geological and climatological processes that have produced contemporary geographic distributions of populations and species. Here, we attempt to understand how the dynamic process of landscape change on Madagascar has shaped the distribution of a targeted clade of mouse lemurs (genus Microcebus) and, conversely, how phylogenetic and population genetic patterns in these small primates can reciprocally advance our understanding of Madagascar's prehuman environment. The degree to which human activity has impacted the natural plant communities of Madagascar is of critical and enduring interest. Today, the eastern rainforests are separated from the dry deciduous forests of the west by a large expanse of presumed anthropogenic grassland savanna, dominated by the Family Poaceae, that blankets most of the Central Highlands. Although there is firm consensus that anthropogenic activities have transformed the original vegetation through agricultural and pastoral practices, the degree to which closed-canopy forest extended from the east to the west remains debated. Phylogenetic and population genetic patterns in a five-species clade of mouse lemurs suggest that longitudinal dispersal across the island was readily achieved throughout the Pleistocene, apparently ending at ∼55 ka. By examining patterns of both inter- and intraspecific genetic diversity in mouse lemur species found in the eastern, western, and Central Highland zones, we conclude that the natural environment of the Central Highlands would have been mosaic, consisting of a matrix of wooded savanna that formed a transitional zone between the extremes of humid eastern and dry western forest types.

https://www.pnas.org/content/pnas/113/29/8049.full.pdf

Geogenetic patterns in mouse lemurs (genus Microcebus) reveal the ghosts of Madagascar's forests past.

Systematic genetic studies of a handful of diverse organisms over the past 50 years have transformed our understanding of biology. However, many aspects of primate biology, behavior, and disease are absent or poorly modeled in any of the current genetic model organisms including mice. We surveyed the animal kingdom to find other animals with advantages similar to mice that might better exemplify primate biology, and identified mouse lemurs (Microcebus spp.) as the outstanding candidate. Mouse lemurs are prosimian primates, roughly half the genetic distance between mice and humans. They are the smallest, fastest developing, and among the most prolific and abundant primates in the world, distributed throughout the island of Madagascar, many in separate breeding populations due to habitat destruction. Their physiology, behavior, and phylogeny have been studied for decades in laboratory colonies in Europe and in field studies in Malagasy rainforests, and a high quality reference genome sequence has recently been completed. To initiate a classical genetic approach, we developed a deep phenotyping protocol and have screened hundreds of laboratory and wild mouse lemurs for interesting phenotypes and begun mapping the underlying mutations, in collaboration with leading mouse lemur biologists. We also seek to establish a mouse lemur gene “knockout” library by sequencing the genomes of thousands of mouse lemurs to identify null alleles in most genes from the large pool of natural genetic variants. As part of this effort, we have begun a citizen science project in which students across Madagascar explore the remarkable biology around their schools, including longitudinal studies of the local mouse lemurs. We hope this work spawns a new model organism and cultivates a deep genetic understanding of primate biology and health. We also hope it establishes a new and ethical method of genetics that bridges biological, behavioral, medical, and conservation disciplines, while providing an example of how hands-on science education can help transform developing countries.

https://www.genetics.org/content/genetics/206/2/651.full.pdf

The Mouse Lemur, a Genetic Model Organism for Primate Biology, Behavior, and Health

Background and aims - The Catalogue of the Vascular Plants of Madagascar project aims to evaluate and enumerate the native and naturalized vascular plant flora of Madagascar. In light of the past two decades of intensive collecting and taxonomic work, all relevant published literature and available specimens are being reassessed in order to evaluate the taxonomic status and distribution of the native and naturalized taxa of vascular plants. Here we provide current figures for the total numbers of vascular plants and levels of endemism at the order, family, genus and species levels, comparing them to previous historical counts and analyzing the distribution of the non-endemic element of the flora. Key Results - At the time of writing (April 2010), more than a century after Baron first counted 4,100 species of vascular plants in Madagascar, the Madagascar Catalogue database had registered a total of 14,883 accepted names at all taxonomic levels (64 orders, 243 families, 1,730 genera, 11,220 species and 1,626 infraspecific taxa). Of the 11,220 species of vascular plants in Madagascar, 10,650 (95%) are angiosperms, of which 331 are naturalized introduced species. The remaining accepted indigenous angiosperm species total 10,319, of which 8,621 (84%) are endemic to Madagascar (82% endemism for all indigenous vascular plants). Among the 1,698 non-endemic species of indigenous angiosperms, a total of 1,372 (81%) also occur in Africa, of these 654 (39%) are present only in Africa and Madagascar.

The endemic and non-endemic vascular flora of Madagascar updated

RESUME Une revision taxonomique du genre Ivodea Capuron est presentee. Trente especes sont reconnues dont 27 endemiques de Madagascar, deux endemiques des Comores et une commune aux deux archipels. Dix-sept especes sont nouvellement decrites (I. acuminata Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. analalavensis Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. ankeranensis Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. antilahimenae Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. aymoniniana Rabarim., Rakoton., Phillipson, Lowry & M.Pignal, sp. nov., I. capuronii Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. delphinensis Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. macrocarpa Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. mahaboensis Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. mananarensis Rabarim., Rakoton., Phillipson & Lowry, sp. nov., I. mayottensis Labat & M.Pignal, sp. nov., I. moheliensis M.Pignal & Labat, sp. nov., I. occidentalis Rabarim., Rak...

Révision du genre Ivodea Capuron (Rutaceae), endémique de Madagascar et de l'archipel des Comores

Rakotonirina, N., M. W. Callmander, P. B. Phillipson & J. M. Lock (2014). Two new species of Xyris L. (Xyridaceae) endemic to Madagascar with a key to the Malagasy species. Candollea 69: 171–178. In English, English and French abstracts. A review of the available herbarium material and of the currently recorded species of the genus Xyris L. (Xyridaceae) from Madagascar in the context of the “Catalogue of the Vascular Plants of Madagascar” project has led us to identify two new species which are described here as: Xyris labatii Rakoton., Callm. & Phillipson and Xyris marojejyensis Lock, Rakoton., Callm. & Phillipson. This brings the total number of species that we recognize on the island to seven. A key to the Malagasy species of Xyris, illustrations of the new species and a discussion of their morphological affinities are provided, together with preliminary conservation status assessments following IUCN Red List Categories and Criteria.

https://www.ville-ge.ch/cjb/publications/cando692/C692_171-178.pdf

Nivo Rakotonirina

Papers

The endemic and non-endemic vascular flora of Madagascar updated

Révision du genre Ivodea Capuron (Rutaceae), endémique de Madagascar et de l'archipel des Comores

Two new species of Xyris L. (Xyridaceae) endemic to Madagascar with a key to the Malagasy species