Maria Cristina Duarte

Genetic diversity of three endangered species of Echium L. (Boraginaceae) endemic to Cape Verde Islands

Echium hypertropicum, E. stenosiphon and E. vulcanorum are the three endemics representative of the genus Echium (Boraginaceae) in Cape Verde archipelago. The aim of this study is to provide a first attempt at estimating genetic diversity among natural populations of these endangered Echium species based on RAPD, so as to provide data available for future appropriate strategies for their conservation. PCO and UPGMA of RAPD analysis suggests a close genetic proximity between the Southern endemic species (E. hypertropicum and E. vulcanorum) and shows that the levels of polymorphism strongly differ between these two Echium species (27 and 29% respectively) and E. stenosiphon (74%), the Northern endemic species. Mantel test also corroborates a close genetic proximity between genetic and geographic data. Population genetic analysis of E. stenosiphon revealed low levels of gene flow between islands (Nm = 0.32) being S. Nicolau the most isolated as evident in PCO. Furthermore the differentiation between groups of individuals belonging to putative subspecies was tested by AMOVA. According to our results there is no genetic basis to consider the two subspecies of E. stenosiphon namely ssp. stenosiphon and ssp. lindbergii. Our results enable us to suggest that E. stenosiphon must be ranked as a Threatened species. Measures aiming at conservation of E. hypertropicum and E. vulcanorum must be implemented at short-term taking into account the small number of existing plants and its low genetic variability.

Exploring the floristic diversity of tropical Africa

BackgroundUnderstanding the patterns of biodiversity distribution and what influences them is a fundamental pre-requisite for effective conservation and sustainable utilisation of biodiversity. Such knowledge is increasingly urgent as biodiversity responds to the ongoing effects of global climate change. Nowhere is this more acute than in species-rich tropical Africa, where so little is known about plant diversity and its distribution. In this paper, we use RAINBIO – one of the largest mega-databases of tropical African vascular plant species distributions ever compiled – to address questions about plant and growth form diversity across tropical Africa.ResultsThe filtered RAINBIO dataset contains 609,776 georeferenced records representing 22,577 species. Growth form data are recorded for 97% of all species. Records are well distributed, but heterogeneous across the continent. Overall, tropical Africa remains poorly sampled. When using sampling units (SU) of 0.5°, just 21 reach appropriate collection density and sampling completeness, and the average number of records per species per SU is only 1.84. Species richness (observed and estimated) and endemism figures per country are provided. Benin, Cameroon, Gabon, Ivory Coast and Liberia appear as the botanically best-explored countries, but none are optimally explored. Forests in the region contain 15,387 vascular plant species, of which 3013 are trees, representing 5–7% of the estimated world’s tropical tree flora. The central African forests have the highest endemism rate across Africa, with approximately 30% of species being endemic.ConclusionsThe botanical exploration of tropical Africa is far from complete, underlining the need for intensified inventories and digitization. We propose priority target areas for future sampling efforts, mainly focused on Tanzania, Atlantic Central Africa and West Africa. The observed number of tree species for African forests is smaller than those estimated from global tree data, suggesting that a significant number of species are yet to be discovered. Our data provide a solid basis for a more sustainable management and improved conservation of tropical Africa’s unique flora, and is important for achieving Objective 1 of the Global Strategy for Plant Conservation 2011–2020.

RAINBIO: a mega-database of tropical African vascular plants distributions

Abstract The tropical vegetation of Africa is characterized by high levels of species diversity but is undergoing important shifts in response to ongoing climate change and increasing anthropogenic pressures. Although our knowledge of plant species distribution patterns in the African tropics has been improving over the years, it remains limited. Here we present RAINBIO, a unique comprehensive mega-database of georeferenced records for vascular plants in continental tropical Africa. The geographic focus of the database is the region south of the Sahel and north of Southern Africa, and the majority of data originate from tropical forest regions. RAINBIO is a compilation of 13 datasets either publicly available or personal ones. Numerous in depth data quality checks, automatic and manual via several African flora experts, were undertaken for georeferencing, standardization of taxonomic names and identification and merging of duplicated records. The resulting RAINBIO data allows exploration and extraction of distribution data for 25,356 native tropical African vascular plant species, which represents ca. 89% of all known plant species in the area of interest. Habit information is also provided for 91% of these species.

Documenting biogeographical patterns of African timber species using herbarium records: a conservation perspective based on native trees from Angola.

In many tropical regions the development of informed conservation strategies is hindered by a dearth of biodiversity information. Biological collections can help to overcome this problem, by providing baseline information to guide research and conservation efforts. This study focuses on the timber trees of Angola, combining herbarium (2670 records) and bibliographic data to identify the main timber species, document biogeographic patterns and identify conservation priorities. The study recognized 18 key species, most of which are threatened or near-threatened globally, or lack formal conservation assessments. Biogeographical analysis reveals three groups of species associated with the enclave of Cabinda and northwest Angola, which occur primarily in Guineo-Congolian rainforests, and evergreen forests and woodlands. The fourth group is widespread across the country, and is mostly associated with dry forests. There is little correspondence between the spatial pattern of species groups and the ecoregions adopted by WWF, suggesting that these may not provide an adequate basis for conservation planning for Angolan timber trees. Eight of the species evaluated should be given high conservation priority since they are of global conservation concern, they have very restricted distributions in Angola, their historical collection localities are largely outside protected areas and they may be under increasing logging pressure. High conservation priority was also attributed to another three species that have a large proportion of their global range concentrated in Angola and that occur in dry forests where deforestation rates are high. Our results suggest that timber tree species in Angola may be under increasing risk, thus calling for efforts to promote their conservation and sustainable exploitation. The study also highlights the importance of studying historic herbarium collections in poorly explored regions of the tropics, though new field surveys remain a priority to update historical information.

Hidden diversity in wild Beta taxa from Portugal: Insights from genome size and ploidy level estimations using flow cytometry

Crop wild relatives constitute a broad pool of potentially useful genetic resources for plant breeders. The genus Beta L. (Amaranthaceae) is an important source of crops, primarily for sugar production. Until recently, species within Section Beta were mostly cytogenetically uniform, with diploidy being prevalent. Still, with the discovery of tetraploid individuals of the wild B. macrocarpa in the Canary Islands, a large-scale study was necessary to evaluate the cytogenetic diversity within the wild Beta. For that, genome size and ploidy level of B. vulgaris subsp. maritima and B. macrocarpa from 21 populations across Portugal mainland and islands, including all know populations of the later taxon, were estimated using propidium iodide flow cytometry. This work revealed a cytogenetically diverse scenario. The analyzed populations were mostly diploid, except for one population of B. vulgaris subsp. maritima that presented both diploid and tetraploid individuals, and for two populations of B. macrocarpa where two or three cytotypes (diploids, tetraploids and/or hexaploids) were found. The nuclear DNA content of diploid individuals was estimated as 1.44±0.035 and 1.41±0.027 pg/2C for B. vulgaris subsp. maritima and B. macrocarpa, respectively. Also, leaves of both species presented variable levels of endopolyploidy. The obtained results are discussed within the context of interspecific hybridization and cryptic diversity and constitute significant data for the conservation of these wild Beta crop relatives.

Systematics and Ecology of a New Species of Seagrass (Thalassodendron, Cymodoceaceae) from Southeast African Coasts

Abstract.  Tropical seagrass communities are one of the most productive aquatic ecosystems on earth. A high diversity of seagrass species occurs in southeastern Africa; however, these marine angiosperms are among the least studied in the world. To address this, we have revised Thalassodendron Hartog (Cymodoceaceae), one of the most representative seagrasses in these coastal waters. Morpho-anatomical analyses, complemented with field data, reveal that specimens from rocky habitats present a number of distinguishing characters (e.g., rhizome internode lengths, leaf epidermal cells, and flower structures) that recommend their exclusion from the species T. ciliatum (Forssk.) Hartog. A new species from rocky habitats, T. leptocaule Maria C. Duarte, Bandeira & Romeiras, is thus described and illustrated, with the type from Mozambique, and an identification key for the investigated taxa is presented.

Evolutionary and Biogeographic Insights on the Macaronesian Beta-Patellifolia Species (Amaranthaceae) from a Time-Scaled Molecular Phylogeny.

The Western Mediterranean Region and Macaronesian Islands are one of the top biodiversity hotspots of Europe, containing a significant native genetic diversity of global value among the Crop Wild Relatives (CWR). Sugar beet is the primary crop of the genus Beta (subfamily Betoideae, Amaranthaceae) and despite the great economic importance of this genus, and of the close relative Patellifolia species, a reconstruction of their evolutionary history is still lacking. We analyzed nrDNA (ITS) and cpDNA gene (matK, trnH-psbA, trnL intron, rbcL) sequences to: (i) investigate the phylogenetic relationships within the Betoideae subfamily, and (ii) elucidate the historical biogeography of wild beet species in the Western Mediterranean Region, including the Macaronesian Islands. The results support the Betoideae as a monophyletic group (excluding the Acroglochin genus) and provide a detailed inference of relationships within this subfamily, revealing: (i) a deep genetic differentiation between Beta and Patellifolia species, which may have occurred in Late Oligocene; and (ii) the occurrence of a West-East genetic divergence within Beta, indicating that the Mediterranean species probably differentiated by the end of the Miocene. This was interpreted as a signature of species radiation induced by dramatic habitat changes during the Messinian Salinity Crisis (MSC, 5.96–5.33 Mya). Moreover, colonization events during the Pleistocene also played a role in shaping the current diversity patterns among and within the Macaronesian Islands. The origin and number of these events could not be revealed due to insufficient phylogenetic resolution, suggesting that the diversification was quite recent in these archipelagos, and unravelling potential complex biogeographic patterns with hybridization and gene flow playing an important role. Finally, three evolutionary lineages were identified corresponding to major gene pools of sugar beet wild relatives, which provide useful information for establishing in situ and ex situ conservation priorities in the hotspot area of the Macaronesian Islands.

New national and regional bryophyte records, 45

D. S. G. Henriques, O. V. Ilina, J. E. Gil-Novoa, M. E. Morales-Puentes, S. R. Gradstein, R. Gupta, V. Nath, A. K. Asthana, A. Koczur, M. Lebouvier, A. Mesterházy, F. Mogro, A. Mežaka, Cs. Németh, J. D. Orgaz, Y. Sakamoto, J. Paiva, F. Sales, N. Pande, M. S. Sabovljević, J. Pantivić, A. D. Sabovljević, A. Pérez-Haase, D. Pinheiro da Costa, V. Plášek, J. Sawicki, M. Szczecińska, J. Chmielewski , A. Potemkin , A. Scha 31 32 ̈fer-Verwimp , W. B. Schofield 33 , C. Sérgio, M. Sim-Sim, S. Sjögren, D. Spitale, A. Stebel, S. Ştefănuţ , G. M. Sua 40 ́rez , J 41 . R. Flores , L. Thouvenot , J. Va 41 42 ́ňa , 43

Taxonomy of Echium (Boraginaceae) species from Cape Verde Islands

The morphological variation of endemic species from the Macaronesian Islands has long attracted attention of many taxonomists. The taxonomy of the endemic Echium L. species (E. hypertropicum Webb, E. stenosiphon Webb and E. vulcanorum A.Chev.) from Cape Verde Islands was revised, on the basis of in situ collected material and on herbarium specimens. Our results revealed that the patterns of morphological variation correspond closely to the geographic localisation of the islands groups, and that habit and floral morphology are important for distinguishing the two southern taxa, E. hypertropicum and E. vulcanorum, from the northern species, E. stenosiphon. This species has the same ecological preferences (e.g. altitude; exposition; soil type) in Sao Nicolau, Sao Vicente and Santo Antao Islands. However, the differences in indumentum observed among E. stenosiphon specimens account for the occurrence of different taxonomic groups distributed in these Northern Islands. The two southern species, E. hypertropicum and E. vulcanorum, are morphologically similar, but have different ecological preferences, a pattern of variation similar to other Macaronesian Echium species. Furthermore, the morphological variation observed among the three Cape Verde species, discussed within the general context of Echium taxonomy and closely related genera (e.g. Lobostemon, Echiostachys and Pontechium), suggests that the systematic relationships are beyond the actual circumscription of these genera.

Genetic diversity and differentiation in Patellifolia (Amaranthaceae) in the Macaronesian archipelagos and the Iberian Peninsula and implications for genetic conservation programmes

This is the first comprehensive investigation of the patterns of genetic diversity of Patellifolia species. The main objective of our research work is to determine Most Appropriate crop Wild relative Populations (MAWP) suited to conserve in situ wild relatives of the sugar beet. Individual plant samples of P. patellaris were collected at 26 and of P. procumbens/P. webbiana at seven sites and analysed with 24 and 22 microsatellite markers, respectively. On average 15 alleles per locus were found within the set of 581 P. patellaris and an average of 12 alleles per locus in the set of 172 P. procumbens/P. webbiana individuals. The factorial analysis showed diversity patterns which agree well with the geographic origin of the samples. The genetic data suggest that P. patellaris reproduces mainly by self-fertilisation while P. procumbens/P. webbiana have the signature of out-breeders. The measure Δ was used to calculate the genetic distance of each occurrence to the pooled remaining occurrences, the complement. Occurrences with either the lowest or the highest genetic distance to the complement are particularly suited to conserve the genetic diversity of the species. Eight occurrences of P. patellaris, two of P. procumbens and one for P. webbiana were determined according to this scheme, proposed as MAWP and recommended for the establishment of genetic reserves.