Southern South American Research Articles

Population genomics indicates micro‐refuges and riverine barriers for a southern South American grassland nightshade

AbstractAimPleistocene climate oscillations influenced the species distribution and genetic diversity in grasslands, and such climatic changes promoted expansion and contraction cycles, leading to fragmentation and isolation of evolutionary lineages in refuges. This study aimed to infer the evolutionary processes that most influenced the genetic diversity of a South American nightshade Petunia inhabiting subtropical grasslands under the Pleistocene influence.LocationPampa and Chaco.TaxonThe widely distributed herb Petunia axillaris subsp. parodii (Solanaceae).MethodsWe obtained high‐density genome coverage throughout the geographical distribution of Petunia axillaris subsp. parodii. We estimated the genetic diversity and structure to evaluate population differentiation and applied a model‐based demographic analysis to investigate the scenarios that could have influenced the species' evolutionary history. We evaluated the association between neutral and outlier polymorphisms with environmental variables to distinguish the influence of the geographical distance and environmental differences between populations.ResultsThere are three evolutionary lineages in P. axillaris subsp. parodii. The origin and differentiation of these lineages were related to the Pleistocene refuges and rivers acting as barriers to gene flow. We also identified 496 outlier loci related to adaptation to environmental conditions.Main conclusionThe Pleistocene climate changes drove lineage diversification isolated in micro‐refugia. Rivers and changes in their courses may have also acted on the population divergence, serving as barriers to gene flow or even as corridors for species range expansion. These findings contribute to the knowledge of the evolutionary processes that influenced the lineage diversification of South American subtropical grassland species.

Ecophysiological responses of southern South American Proteaceae to nutrient deprivation are related to their edaphic distributions

Ecophysiological responses of southern South American Proteaceae to nutrient deprivation are related to their edaphic distributions

Occurrence of kleptoparasitic sarcophagid flies (Diptera: Sarcophagidae: Miltogramminae) in natural and human modified sites in Southern South American Andean landscapes

Sarcophagid flies belonging to the subfamily Miltogramminae are mainly kleptoparasites of bees and solitary wasps. Twenty-six locations were surveyed to accomplish the first specific exploration on the diversity of Miltogramminae in southern Andean areas of South America. We evaluated changes in abundance, richness and composition among habitat types to establish the effect of anthropization on the Miltogramminae community. Habitat types were considered as human modified (trails and roads, parks and meadows) and natural sites (watercourses and lake beaches, sandy and shrubby areas), distributed in two ecoregions (Valdivian forest and Patagonian steppe). We found differences in the capture rate and composition of Miltogramminae among habitat types. The species Opsidia intonsa Aldrich was highly dominant in samples, with higher proportional abundance in human modified habitats. Richness of Miltogramminae was higher in natural sites. Comparisons between the ecoregions surveyed indicated the genus Opsidia Coquillett did not show differences in abundance between ecoregions, whereas Senotainia Macquart was more abundant in the Patagonian steppe. The results provide evidence on the significant effects of human influence on landscapes in kleptoparasitic fly diversity. Slight modifications of natural areas (as proliferation of trails or isolated houses) should be addressed to evaluate the conservation of kleptoparasitic Diptera.

Exploring the role of climatic niche changes in the evolution of the southern South American genus Baripus (Coleoptera: Carabidae): optimization of non-hereditary climatic variables and phylogenetic signal measurement.

Baripus is a ground beetle genus endemic to southern South America, currently distributed across grassland and shrub habitats in mountain and lowland regions. The species of this genus are known to have been affected by the Andean orogeny and the climate changes that occurred during this process. In this study, we seek to understand how the orogeny of the Andes may have led to changes in the climatic niches of the species of Baripus over time. We integrated former ecological and historical biogeographic hypotheses, exploring the use of parsimony optimization of phylogenetically structured climate variables and ancestral character state reconstruction methods. We then performed regression analyses of the optimized climatic niche variables within the phylogenetic tree of Baripus. We were able to infer significant climatic niche constraints, and niche changes that provide new insights to the existing knowledge, supporting former ecological and biogeographic hypotheses for this genus. Such trends in climatic niche could be explained by the rain shadow effect caused by the Andean uplift as well as with other climate shifts associated with temperature and precipitation swings that occurred in this region from the Middle Miocene to the Pliocene.

Modeling the 20th-century distribution changes of Microgyne trifurcata, a rare plant of the southern South American grasslands

Microgyne trifurcata is a rare native plant species from one of the areas with the highest human impact on the environment in southern South America. Its habitat, mostly grasslands suitable for agriculture, has been increasingly covered by crops since the late 1800s. Microgyne trifurcata provides an excellent case study to understand how different environmental variables have affected the distribution area of a rare species. This study aims to estimate the impact of topoclimatic and land-use changes in the distribution of Microgyne trifurcata throughout the twentieth century. We carried out recent past and present distribution modeling using the Ensembles of Small Models (ESM) methodology. In this spatio-temporal study, we included climatic, topographic, and land-use variables. We classified the occurrences into two periods of the twentieth century. The first dates from 1901 to 1940, and the second, from 1960 to 2000, when the main cropping changes of the area occurred. The projected area between 1960 and 2000 provides for this species new suitable habitats toward the northeast of the area of study. Our results highlight the importance of assessing the combined impacts of climate and land-use changes on species distributions over time. This study shows that the potential area of Microgyne trifurcata decreased and underwent fragmentation throughout the twentieth century when these variables combined are used to model its distribution. Our outcomes prompt future studies on the vulnerability of Microgyne trifurcata to outline conservation strategies.

Revision of the genusBuccinanops(Mollusca: Neogastropoda: Nassariidae), an endemic group of gastropods from the Southwestern Atlantic, including a new genus and accounts on the Buccinanopsinae classification

The nominal species referred to the endemic southern South American genus Buccinanops are revised, clarifying the definition of Buccinanopsinae. All valid Recent species are redescribed based on type material and other specimens emphasizing anatomy and illustrated using SEM photographs of radulae, embryos, and shell ultrastructure. Only seven of 13 nominal species described are considered valid: Buccinanops cochlidium (Dillwyn, 1817) (type species); B. latus sp. nov. (formerly B. gradatus or B. lamarckii from Brazil only); B. monilifer (Kiener, 1834); B. deforme (King, 1832); B. paytense (Kiener, 1834); B. uruguayense (Pilsbry, 1897) and B. duartei Klappenbach, 1961. A phylogenetic analysis based on morphological characters of these species and 12 other buccinoideans is carried out in order to compare results with recent DNA sequence approaches. The ingroup cladogram is ((B. monilifer (B. latus-B. cochlidium)) (B. duartei (B. uruguayense (B. deforme-B. paytense)))). The former genus Buccinanops, supported by 11 synapomorphies, can be divided, and Buccinastrum gen. nov. (3 synapomorphies of support) is introduced for the 4 latter species in the above cladogram; its type species is Buccinastrum deforme. Buccinanops (8 synapomorphies) is thus restricted to B. cochlidium, B. monilifer, and B. latus, which are large-sized, living in relative deep waters (subtidal), while Buccinastrum includes small-sized species mostly restricted to the intertidal zone. The analysis of morphological characters is suggestive of a traditional subfamily Dorsaninae, with 12 synapomorphies, including four genera—Dorsanum, Bullia, Buccinanops, and the new Buccinastrum, but this result is only informative, as it has been considered paraphyletic in a DNA sequence approach, being subdivided into Dorsaninae, Buccinanopsinae, and Buliinae.

Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae)

AbstractPterocactus has 10 species endemic to restricted areas of the Argentine Monte and Patagonia regions, also growing in neighbouring Chile. We analysed phylogenetic relationships between its species, based on plastid DNA sequences (psbA‐trnH, rpl16, trnH‐matK), exomorphological features (spine type and size, stem segment form, flower position, epidermis colour, areole pubescence, stem surface) and cytogenetical traits (genome size, somatic chromosome number). Traits were mapped using character mapping and ancestral state reconstruction to understand the dynamics of evolutionary changes. Pterocactus was monophyletic. Two lineages were recovered: clade A (with P. fischeri diverging early and P. reticulatus, P. valentinii, P. megliolii, P. gonjianii, and both P. tuberosus forms) and clade B (with P. neuquensis diverging first and P. araucanus and P. hickenii). Both samples examined of P. australis were paraphyletic. It was estimated that Pterocactus split from its sister group at 9.38 mya. The crown group age was estimated to be 7.69 myr. Species showed x = 11 with different ploidy levels (2n = 22, 44, 99, ca. 110, and 154); only P. tuberosus f. tuberosus was diploid. The numbers were typical of each taxon studied, and polyploidy was important in its diversification. Two 18S‐5.8S‐26S sites were detected regardless of the ploidy level, except P. fischeri with four sites and 2n = ca. 110. The number of 5S sites was 2 in P. gonjianii and the diploid P. tuberosus f. tuberosus, 4 in the tetraploid P. tuberosus f. lelongii, 10 in the probably decaploid P. fischeri and 8 in P. araucanus of unknown chromosome number. The genome size ranged from 2C = 4.94 pg in P. megliolii of unknown chromosome number to 2C = 16.68 pg in the tetradecaploid P. hickenii. The ancestor is reconstructed as a dwarf shrub with cylindrical central spines of 16.35–31.2 mm long, non‐woolly areoles, cylindrical to globose/obpyriform stem segments, non‐tuberculate stem surface, lateral flower position, green/brown to violet epidermis, probably diploid, and with a genome size between 1.10 and 1.23 pg.

Molecular analysis suggests that Namibian cheetahs (Acinonyx jubatus) are definitive hosts of a so far undescribed Besnoitia species

BackgroundBesnoitia darlingi, B. neotomofelis and B. oryctofelisi are closely related coccidian parasites with felids as definitive hosts. These parasites use a variety of animal species as intermediate hosts. North American opossums (Didelphis virginiana), North American southern plains woodrats (Neotoma micropus) and South American domestic rabbits (Oryctolagus cuniculus) are intermediate hosts of B. darlingi, B. neotomofelis and B. oryctofelisi, respectively. Based on conserved regions in the internal transcribed spacer-1 (ITS1) sequence of the ribosomal DNA (rDNA), a real-time PCR for a sensitive detection of these Besnoitia spp. in tissues of intermediate hosts and faeces of definitive hosts has recently been established. Available sequence data suggest that species such as B. akodoni and B. jellisoni are also covered by this real-time PCR. It has been hypothesised that additional Besnoitia spp. exist worldwide that are closely related to B. darlingi or B. darlingi-like parasites (B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni). Also related, but not as closely, is B. besnoiti, the cause of bovine besnoitiosis.MethodsFaecal samples from two free-ranging cheetahs (Acinonyx jubatus) from Namibia that had previously tested positive for coccidian parasites by coproscopy were used for this study. A conventional PCR verified the presence of coccidian parasite DNA. To clarify the identity of these coccidia, the faecal DNA samples were further characterised by species-specific PCRs and Sanger sequencing.ResultsOne of the samples tested positive for B. darlingi or B. darlingi-like parasites by real-time PCR, while no other coccidian parasites, including Toxoplasma gondii, Hammondia hammondi, H. heydorni, B. besnoiti and Neospora caninum, were detected in the two samples. The rDNA of the B. darlingi-like parasite was amplified and partially sequenced. Comparison with existing sequences in GenBank revealed a close relationship to other Besnoitia spp., but also showed clear divergences.ConclusionsOur results suggest that a so far unknown Besnoitia species exists in Namibian wildlife, which is closely related to B. darlingi, B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni. The cheetah appears to be the definitive host of this newly discovered parasite, while prey species of the cheetah may act as intermediate hosts.Graphical

Ecophysiological Performance of Proteaceae Species From Southern South America Growing on Substrates Derived From Young Volcanic Materials.

Southern South American Proteaceae thrive on young volcanic substrates, which are extremely low in plant-available phosphorus (P). Most Proteaceae exhibit a nutrient-acquisition strategy based on the release of carboxylates from specialized roots, named cluster roots (CR). Some Proteaceae colonize young volcanic substrates which has been related to CR functioning. However, physiological functioning of other Proteaceae on recent volcanic substrates is unknown. We conducted an experiment with seedlings of five Proteaceae (Gevuina avellana, Embothrium coccineum, Lomatia hirsuta, L. ferruginea, and L. dentata) grown in three volcanic materials. Two of them are substrates with very low nutrient concentrations, collected from the most recent deposits of the volcanoes Choshuenco and Calbuco (Chile). The other volcanic material corresponds to a developed soil that exhibits a high nutrient availability. We assessed morphological responses (i.e., height, biomass, and CR formation), seed and leaf macronutrient and micronutrient concentrations and carboxylates exuded by roots. The results show that G. avellana was less affected by nutrient availability of the volcanic substrate, probably because it had a greater nutrient content in its seeds and produced large CR exuding carboxylates that supported their initial growth. Embothrium coccineum exhibited greater total plant height and leaf P concentration than Lomatia species. In general, in all species leaf macronutrient concentrations were reduced on nutrient-poor volcanic substrates, while leaf micronutrient concentrations were highly variable depending on species and volcanic material. We conclude that Proteaceae from temperate rainforests differ in their capacity to grow and acquire nutrients from young and nutrient-poor volcanic substrates. The greater seed nutrient content, low nutrient requirements (only for G. avellana) and ability to mobilize nutrients help explain why G. avellana and E. coccineum are better colonizers of recent volcanic substrates than Lomatia species.

An assessment of subduction zone-generated tsunami hazards in New Zealand Ports

For the role they play in domestic and international shipping and inter-island transport, ports are a critical part of New Zealand’s infrastructure network. With ports located along coastlines having similar exposure to tsunami hazards, multiple facilities could experience structural damage and operational disruption during a single event. In this study, we evaluated tsunami effects in terms of water levels and current speeds at 13 ports as caused by both local and distant source subduction zone earthquakes over a range of source moment magnitude scenarios. The results suggest that while the tsunami hazard varies between ports, it is generally highest along the eastern coastline due to its exposure to tsunami generated along the Southern Kermadec, Hikurangi and South American Subduction Zones. While a Hikurangi earthquake has the potential to generate the most devastating impacts at individual ports, an earthquake off the Peruvian coastline has the potential to impact operations and infrastructure at the largest number of ports. Such an event could affect international trade capacity, regional recovery and domestic inter-island transport. Due to the potential for damage and disruption at multiple ports in a single event, this study highlights the importance of a broader national and international transport system perspective to inform potential resilience investments.

Paleoenvironmental changes in southern South American dust sources during the last glacial/interglacial transition: Evidence from clay mineral assemblages of the pampean loess

abstract Paleoclimatic reconstruction is critical for understanding present-day climate and for testing models that are currently used to predict future climatic changes. Different climatic conditions produce different clay minerals that can be recorded in geological archives providing insights into past weathering scenarios. However, in southern South America, scarce information is available from clay mineral assemblages found in aeolian sediments, such as loess deposits. Moreover, there is a lack of studies employing clay minerals for paleoclimatic reconstruction at dust sources and loess deposits. Therefore, this work explores clay mineral composition of modern dust source areas in southern South America and in the pampean loess records to gain insight into paleoenvironmental conditions prevailing during the late Pleistocene-early Holocene in the region. Clay minerals recovered from the loess deposits are of an allochthonous origin, implying their formation at the ‘arid diagonal’, then blown away, and deposited downwind in the Pampas without post-depositional changes. Clay mineral assemblages indicate that these minerals and rare earth elements (REE) analyzed in two loess sections of the Pampean Plain helped to reconstruct past climatic scenarios in the dust source areas during the transition from the last glacial to the current interglacial period. Furthermore, our work contributes to the assessment of the strengthening/weakening of the different South American dust sources in light of recent published geochemical and textural evidence.

Amazonian scorpions and scorpionism: integrating toxinological, clinical, and phylogenetic data to combat a human health crisis in the world's most diverse rainfores.

Venom from Amazonian scorpions of the genus Tityus contains components capable of eliciting a distinct clinical, mostly neurological, syndrome. This contrasts with the mainly autonomic manifestations produced after envenomation by congeneric southern and northern South American species. Herein, we summarize Pan-Amazonian scorpionism by synthesizing available toxinological, clinical, and molecular data gathered from all affected areas in Amazonia, including Brazil, Ecuador, Colombia, Peru, Venezuela, and French Guiana. We searched multiple databases, as well as our own records, for reports of scorpion envenomations in Amazonia by confirmed Tityus spp., and compared the clinical manifestations. To help uncover clinical and venom relationships among problematic species, we explored phylogenetic relationships with a rate-calibrated analysis of mitochondrial COI data from available species. The possible existence of diversity gradients for venom toxic and immunogenic components despite the predicted strong phylogenetic association among species is underscored by discussed clinical and toxinological findings. A multicentric effort, involving all nations affected by this neglected disease, is urgently needed to offer alternatives for treating and understanding this pathology, including the preparation of neutralizing antibodies with a broad range of efficacy.

Hispidopannaria and Phormopsora, two new and small, but evolutionary old Pannariaceae lichen genera from southern South America

Based on phylogenetic analyses of the ITS, nuclear large subunit rRNA, mitochondrial small subunit rRNA, and MCM7 genes, species previously treated as Pannaria hispidula and P. isabellina are shown to represent two new Pannariaceae genera, Hispidopannaria and Phormospsora. Each genus forms monophyletic clades, both in multilocus phylogeny and in single gene phylogenies. In the multilocus phylogeny, both genera together formed a monophyletic clade as a sister group to the genus Pannaria, whereas this monophyly was not maintained in single gene phylogenies. Hispidopannaria differs from Pannaria in having large, geotropically arranged, hispid squamules, IKI+ internal ascus structures, and perispores with irregular pulvinate verrucae and apical extensions. The southern South American, TLC-negative species H. hispidula is generitype and is concentrated to trunks in the evergreen Nothofagus forests of south-central Chile. Psoroma dasycladum, a similar endemic species from the Juan Fernández Archipelago, is also transferred to Hispidopannaria. Phormopsora is monospecific and is the only member of Pannariaceae which contains norstictic and connorstictic acids. Its thallus of large, branched squamules with large, foliose cephalodia and its bullate perispores with long-apiculate apical extensions also separate it from Pannaria. Its species, Phormopsora isabellina, has a similar distribution as H. hispidula on the South American mainland, but is more widespread. The position of these two small genera as a sister group to the large and diverse genus Pannaria, indicates a long period of slow evolutionary rate, with the island endemic Hispidopannaria dasyclada as an exception. Reproductive isolation and photobiont specialization are partly suggested to explain their slow evolution and lack of surviving speciation.

Contribución al conocimiento de la biota liquénica de la Reserva Nacional Katalalixar, Patagonia, Chile

Lichens are recognized as bioindicators of ecosystem processes associated with environmental disturbances. However, its evaluation in the time requires systematic records of biodiversity which are non-existent in the Katalalixar National Reserve. The aim of this study was to catalog the richness and distribution of lichen biota of Katalalixar National Reserve, not only by identifying the species but interpreting them in their ecological and biogeographic context. By random sampling in Nothofagus nitida, Pilgerodendron uviferum forests and peat bogs 70 species were identified, belonging to 32 families and 65 genera. A high number of endemism was found, with 34% of the species endemic to Southern South American and the Chilean endemic Pseudocyphellaria guzmanii constitutes a new record for the Aisen Region.

Temporal and population trends in human exploited pinnipeds from Tierra del Fuego

Archaeological sites on the coast of Tierra del Fuego, Argentina, provide a biogeochemical record that can inform us about those ecological dynamics. An abundance of southern fur seal (Arctocephalus australis) and southern sea lion (Otaria flavescens) remains provide a valuable resource to reconstruct ancient and modern food webs. To quantify ecological relationships, we measured bulk stable isotope ratios from bone collagen in otariids and other associated animals, several of which are potential otariid prey. Variations in bulk stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) are linked to potential dietary differences and habitat specialization between coastal areas or the open ocean in populations ranging in age from 7000 cal. Years BP to modern. We observed increases in the variability of these isotopic compositions over time, which suggests a diversity in the diets and habitats of otariids. Shifts in marine food webs occurred during the transition from subsistence hunting of otariids to industrial hunting and expanded human influence. We conclude that direct human influences, such as hunting and habitat alteration, were the major drivers of ecological change in southern South American marine ecosystems.

A cyclic dipeptide from the Chilean hazelnut cotyledons (Gevuina avellana Mol., Proteaceae)

The Chilean hazelnut (Gevuina avellana Mol., Proteaceae) is a southern South American nut consumed as a snack and included in different preparations of traditional Chilean cuisine. Recently we described the fatty acid profile, oxylipins, phenolic compounds, as well as the antioxidant capacity. The main compounds of the phenolic-enriched extract were only tentatively identified by spectrometric means. In the present work, we describe the isolation and full characterization of a cyclic dipeptide cyclo(Arg-Trp) and other compounds from the phenolic enriched extracts of the G. avellana cotyledons. Compounds were isolated by means of counter-current chromatography and structures were established by spectroscopic and spectrometric methods. This is the first report on small peptides in G. avellana and adds evidence on the possible beneficial effects of this nut in human health.

Integrative taxonomy of the southernmost tucu-tucus in the world: differentiation of the nominal forms associated with Ctenomys magellanicus Bennett, 1836 (Rodentia, Hystricomorpha, Ctenomyidae)

We reviewed the alpha taxonomy of the genus Ctenomys Blainville, 1826 in southernmost South America, with emphasis on those nominal forms previously associated with C. magellanicus Bennett, 1836. We integrate distinct lines of evidence, including variation of mtDNA sequences, and the assessment of quantitative and qualitative traits of skins and skulls; when available, karyotypic data was also considered. Phylogenetic analysis of molecular markers shows low levels of divergence among specimens from southern South American mainland and the island of Tierra del Fuego (ca. 0.4%). This evidence plus the results of the multivariate analysis of metric data suggest that the nominal forms C. colburni J. A. Allen, 1903, C. fueginus Philippi, 1880, C. osgoodi J. A. Allen, 1905, C. m. dicki Osgood, 1943, and C. m. obscurus Texera, 1975 are subjective junior synonyms of C. magellanicus. In addition, we reviewed the status of C. fodax Thomas, 1910, a nominal form that have been alternatively considered as a valid species or related to C. magellanicus by previous researchers. Based on quantitative and qualitative morphological traits, we preliminarily regard C. fodax at the species level while citing it for the first time to Chile.

Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record

The southern westerly winds (SWW) play a major role in climate variability in Southern Hemisphere mid- and high-latitudes, regulating rainfall, ocean circulation, and the Southern Ocean carbon sink. Despite their importance, little is known about millennial scale changes in the SWW and how they have influenced the climate system in the past and interacted with the Earth’s surface elements, such as dust, nutrients and carbon. Here we present a dust record from a 6.6 kyr old peat core in Amsterdam Island (AMS) situated at the northern edge of the SWW (37°S) in the Southern Indian Ocean. Mineral dust flux was used to track atmospheric dust production, long-distance transport and subsequent deposition. Dust provenance was determined from rare earth element (REE) and Nd isotopic signatures (εNd) in the peat core, compared with a reference dataset of Southern Hemisphere dust sources. Using a multi-proxy mixing model, the εNd and REE ratios show a relatively uniform mixture of ca. 40% local, 15% Southern African and 45% Southern South American dust sources since 6.6 cal kyr BP. However, from 1910 AD onwards, there is a doubling in the contribution from Southern Africa (32%). Two mineral dust flux minima occur at 6.2–4.9 cal kyr BP and 3.9–2.7 cal kyr BP, interpreted as periods with equatorward-shifted and/or strengthened SWW at the northern edge of the wind belt. Conversely, periods of higher dust flux at 6.6–6.2 cal kyr BP, 4.9–3.9 cal kyr BP, and 1.4 cal kyr BP onwards are interpreted as poleward-shifted and/or weakened SWW. These interpretations are based on the findings that higher (lower) wind speeds lead to enhanced (less) removal of distal dust on the way to AMS, by wet deposition and turbulence. Published Holocene SWW records at the northern edge of the wind belt (33–41°S) covering South-America, Southern-Africa and Australia, show much variability over the last 6.6 kyr. We suggest this reflects complex regional climate variability in the different SH longitudinal sectors, indicating that SWW are not zonally homogeneous at the northern edge of the wind belt. The recent shift in dust provenance is not accompanied by enhanced total dust deposition at AMS. We therefore suggest that human impact (e.g., land use changes) and drier climate conditions in Southern Africa have led to enhanced dust mobilization.

<p><strong>The bryophytes of Madre de Dios Archipelago, Magallanes Region, Chile</strong></p>

We present a bryophyte checklist for Madre de Dios Archipelago, located in western Magallanes Region, southern Chile. Madre de Dios is one of the most unique limestone massifs on Earth, and together with Diego de Almagro Island (150 km southward), they are the most extensive of such existing areas in Chile. It is located in the western margins of the southern archipelago region, between Puerto Edén and Puerto Natales. As a result of this first bryophyte collecting effort in calcareous environments in Chile, a total of 152 bryophyte taxa are reported, including two hornworts, 80 liverworts, and 70 moss taxa. From this total, 14 are new records for Magallanes Region and 25 for Última Esperanza Province. Eleven species extend their southern distribution limit, whereas two extend their northern distribution limit. Among the new regional records, we found the rare Vesiculariopsis spirifolium (Dusén) Broth., for which only three previous collections were known, obtaining additional ecological data. Additionally, the only southern South American representative of the tropical family Pleuroziaceae, Pleurozia paradoxa (J.B.Jack) Schiffn. was abundantly found among sandstone tundra. Both sandstone and limestone environments were prospected, the latter alone being inhabited by 100 bryophyte taxa. A liverwort-moss proportion pattern related to a calcareous substrata exposure gradient is discussed, and the most frequent species of the different environments of the islands are characterized. For most bryophytes reported here, these new records fill an important distribution gap in a scarcely explored area.

Weedy ferns (Polypodiopsida) in Argentina: diversity, distribution and impact on human activities and ecosystems.

Currently, in Argentina 368 species of true ferns (i.e. Polypodiopsida class) are distributed throughout the country, however, only four of them have been mentioned until now as weeds and ruderal species. The goal of this work was to generate an update of weedy ferns from Argentina, including morphology, distribution, and type of weed according to their impact on natural habitats and/or human activities. All Argentinian fern species were analyzed based on references, herbarium specimens, and field trips. As a result of our study 25 species were recorded from Argentina and classified as segetal, ecological, or aquatic weeds, and ruderal and/or toxic species. Current taxonomic identity, diagnostic characters, origins, habitats, geographical distribution, common names, and impact and potential risks were indicated by species. In addition, we provide a dichotomous key to species, presence of these species in southern South American countries, as well as and photographs in natural habitat. This work represents the first review on native and exotic ferns from Argentina that cause an impact on human activities or disturbe native habitats. The results provide information for the development of weed management tools and priority areas to implement them.