Family Legacy: Depicting Diversity-Elevation Relationships of Tropical Tree Communities

Unveiling the ecological processes driving diversity and its relationship to the environment remains a central goal in ecological studies. Here, we investigated the elevation effect on plant diversity patterns of tropical rainforests, using beta-, phylogenetic and alpha diversities. To do so, we compiled a forest dataset with 22,236 trees (DBH ≥ 4.8 cm) from 17 plots of 1 ha each along an elevational gradient (0 – 1,200 m a.s.l) in the Atlantic Forest of Southeastern Brazil. We found high phylogenetic and species rates of turnover – beta-diversity - along the elevational gradient. Alpha phylodiversity showed a monotonic decrease with increasing elevation, including or not fern species (a distantly related clade usually ignored in tropical ecology studies), while the phylogenetic structure was highly affected by the inclusion of fern trees. Species diversity showed a unimodal pattern for the whole community, and different patterns for the richest families. The diversity pattern of the whole community emerges from differences among species distribution of the richest families, while phylogenetic diversity seems to be gradually filtered by elevation. At intermediate elevations, higher species diversification within families might have led to different strategies and cooccurrence in tropical rainforests. We also showed that intricate effects of elevation in species assemblages can be better assessed using both ecological and evolutionary approaches, stressing the importance of species selection in diversity analyzes. Finally, we demonstrate that elevation has different effects on the species distributions of the richest families and warn that these differences should be considered in conservation planning.

Identifying cryptic fern gametophytes using DNA barcoding: A review

Ferns and lycophytes are unique among land plants for having sporophyte (diploid) and gametophyte (haploid) generations that can grow independently of each other. While most studies of fern ecology focus on the more obvious sporophytic stage, the gametophyte is critically important, as it is the sexual phase of the life cycle. Yet, fern gametophytes have long been neglected in field studies due to their small size and cryptic morphology. DNA barcoding is a powerful method that can be used to identify field-collected gametophytes to species and allow for detailed study of their ecology. Here, we review the state of DNA barcoding as applied to fern gametophytes. First, we trace the history of DNA barcoding and how it has come to be applied to fern gametophytes. Next, we summarize case studies that show how DNA barcoding has been used to better understand fern species distributions, gametophyte ecology, and community ecology. Finally, we propose avenues for future research using this powerful tool, including next-generation DNA sequencing for in-field identification of cryptic gametophytes.

A horizon scanning approach to rapidly detect alien fern species through horticultural trade

Horticultural trade is a well-documented pathway of introduction for numerous invasive species globally, including ferns. In this study, we analysed trade in terrestrial true ferns (Polypodiophyta) in six anglophone countries: Canada (CA), the United States of America (US), Great Britain and Ireland (GB, for ease of reading), South Africa (ZA), Australia (AU), and New Zealand (NZ). The study provides an overview of fern trade and explored the relationship between trade and alien fern introductions with a view to better inform management interventions. Using a horizon scanning approach in consulting horticultural catalogues, we identified a total of 382 fern species currently traded by 148 traders in a period of just six months. International trade was observed in only three countries with most trade occurring at national scales and e-commerce was not the dominant mode of trade noted in this study, with a relatively higher proportion of species traded on-ground. Alien species accounted for more than 60 % of the total number of traded species in most countries except in AU and NZ, and a surprising number of species (11-14 species per country) known to be naturalised or invasive in their country of trade remain actively traded, with fewer species in CA (2) and AU (5). A total of 194 species noted in trade have not previously been recorded as alien in plant species inventories and did not have an invasion status assigned in their countries of trade. We identified 62 species of concern (i.e., potential future invaders) with Dryopteris erythrosora, Anisocampium niponicum, Polystichum polyblepharum, Austroblechnum penna-marina subsp. penna-marina, Asplenium nidus, Dicksonia antarctica, Polypodium vulgare, and Adiantum raddianum indicated as priority species for regulation in trade due to their high market presence. Citizen science records were noted for very few species of concern with only two records indicating the occurrence of two species in natural or semi-natural areas. This research constitutes one of few studies that have applied a horizon scanning approach using horticultural catalogues to identify alien species, and highlights the efficiency of this approach as a tool for the early detection of potentially invasive species.

Hypodematium chrysolepis comb. nov. from Africa and H. eglandulosum sp. nov. from Asia (Hypodematiaceae)

A new fern species, Hypodematium eglandulosum, is described and illustrated from southern China and Southeast Asia, and a new combination is made, H. chrysolepis, from Africa. Hypodematium eglandulosum is distinguished from its similar species by plants eglandular, leaves 3-pinnatifid, and stipes upward sparsely covered with acicular hairs or nearly glabrous. The description and photographs of H. eglandulosum are provided. Aspidium chrysolepis is currently treated as a synonym of H. crenatum, but it should be recognized.

Pyrrosia sarthalensis, a new species of Polypodiaceae from Kathua District, Jammu and Kashmir, Western Himalaya, India

Pyrrosia sarthalensis, belonging to the family Polypodiaceae from the Bani Valley of Kathua district, Himalayan Jammu & Kashmir, India is described here as a new species. It shows restricted distributional range and so far, is only known from the Bani Valley, within the Himalayan centre of endemism. It is an epiphytic fern species having brownish sori, formed only on the upper half of the frond. Other diagnostic features include grooved rhizomes, rhizome scales, lamina size and structure, sori placement, size and structure, and spore characters. This new species is morphologically similar to P. flocculosa but differs in certain characters.

Transposable element landscapes illuminate past evolutionary events in the endangered fern Vandenboschia speciosa

Vandenboschia speciosa is an endangered tetraploid fern species with a large genome (10.5 Gb). Its geographical distribution is characterized by disjoined tertiary flora refuges, with relict populations that survived past climate crises. Here we analyze the transposable elements (TEs) and found that they comprise about 76% of the V. speciosa genome, thus being the most abundant kind of DNA sequences in this gigantic genome. V. speciosa genome is composed of 51% and 5.6% of Class I and Class II elements, respectively. LTR retrotransposons were the most abundant TEs in this species (at least 42% of the genome), followed by non-LTR retrotransposons that constituted at least 8.7% of the genome of this species. We introduce an additional analysis to identify the nature of non-annotated elements (19% of the genome). A BLAST search of the non-annotated contigs against the V. speciosa TE database allowed determining the identity of almost half of them, which were most likely diverged sequence variants of the annotated TEs. In general, TE composition in V. speciosa resembles TE composition in seed plants. In addition, repeat landscapes revealed three episodes of amplification for all TEs, most likely due to demographic changes associated to past climate crises.

Analysis of Genetic Variability Amongst Polyploid Genotypes of Pteris vittata L. From Various Geographic Locales of India

Pteris vittata L. is very common and a widely distributed species belongs to the family Pteridaceae. Various cytotypes from diploid to octaploid is available in this fern species. The present work has been carried out for genetic diversity in this fern both within and between the cytotypes. The molecular analysis at inter- as well as intra-species has been carried out with 57 accessions of P. vittata as well as of other species of Pteris with Microsorium punctatum considered as an out group taxon. For the present study 48 P. vittata (36 tetraploid and 12 pentaploid) and five of other species (four P. cretica, one P. pellucida, one P. tremula, one P. quadriaurita, and two P. ensiformis) accessions were used. The UPGMA (unweighted pair group method with arithmetic mean) dendrograms were generated for each method separately, as well as for all methods cumulatively, after a 1000 replicate bootstrap analysis. In order to determine the utility of each of the method, a comparative statistical assessment was done and marker index (MI), expected average heterozygosity, fraction of polymorphic loci and effective multiplex ratio (EMR) were calculated in case of each of the methods used in the present study. At the level of individual methods highest MI was obtained for directed amplification of minisatellites DNA (DAMD) method. Our findings of the present study concluded that out of the three methods Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeat (ISSR), and Directed Amplification of Minisatellite DNA (DAMD), DAMD was the best in term of polymorphism and heterozygosity as scores exhibited highest MI. The different accessions of P. vittata collected from different phytogeographical regions falls into six groups. Out of six clusters, one cluster is of pentaploid cytotype, four clusters are of tetraploid cytotype and one for outgroup taxon (M. punctatum). The result thus showed that within tetraploid, heterozygosity with variable genomic structure exists.

Cheilanthes qiaojiaensis (Cheilanthoideae, Pteridaceae), a new fern species from Yunnan, China

Cheilanthes qiaojiaensis, a new fern of Pteridaceae subfamily Cheilanthoideae, is described and illustrated. Morphologically, C. qiaojiaensis is similar to C. chusana and Aleuritopteris rufa in having plants hairiness and laminae elliptic-lanceolate, but the new species has plants covered with dense hairs throughout, petiole and rachis flattened to narrowly grooved, and false indusia wide and continuous. The phylogenetic analysis also shows that C. qiaojiaensis is not a close relative of either A. rufa or C. chusana.