Fairy ring disease affects epiphytic algal assemblages associated with the moss Sanionia uncinata (Hedw.) Loeske (Bryophyta) on King George Island, Antarctica.

Since the nineteenth century, a ring-forming disease attacking Antarctic mosses has been reported. However, to date, only the effects on the mosses themselves are known. In this study, we used DNA metabarcoding to investigate the effects on the moss epiphytic algal community at different stages of disease progression. As the disease progressed, algal species richness decreased, although overall abundance was not significantly affected. Prasiolales appeared unaffected, whereas Ulotrichales were more sensitive. Trebouxiales dominated the advanced disease stage, suggesting a possible benefit from the disease, either through the elimination of competition or creation of new niches. Infection is responsible for moss death, leading to habitat loss for other organisms, but pathogenic effects on algae cannot be ruled out. Our data indicate that the disease not only impacts mosses but also other groups, potentially resulting in loss of Antarctic biodiversity. This study provides the first report of the disease effects on epiphytic algal communities of Antarctic bryophytes.

Assessing species reintroduction sites based on future climate suitability for food resources.

The reintroduction of a species that is extinct in the wild demands caution because reintroduction locations may be associated with threats, such as hunting, poor-quality habitat, and climate change. This is the case for Cyanopsitta spixii (Spix's Macaw), which has been extinct in the wild since 2000. The few living individuals were created in captivity and will be used in a reintroduction project within the species' original distribution area, the Caatinga domain (Brazil). Because the occurrence records for this bird are old and inaccurate, we investigated the current and future environmental suitability of the 14 plant species used by C. spixii as resource. These plants are key elements for the long-term reestablishment of the species in the wild, so the use of models helps in the assessment of the effects of climate change on the availability of these resources for the species and informs selection of the best places for reintroduction. We based our models of environmental suitability on 19 bioclimatic variables and nine physical soil and topography variables. Climate projections were created for the present and for the year 2070 with an optimistic (SSP2-4.5) and a pessimistic (SSP5-8.5) climate scenario. Both future climate scenarios lead to a reduction in area of environmental suitability that overlapped for all the plant species: 33% reduction for SSP2-4.5 and 63% reduction for SSP5-8.5. If our projections materialize, climate change could thus affect the distribution of key resources, and the maintenance of C. spixii would depend on restoration of degraded areas, especially riparian forests, and the preservation of already existing natural areas. The Caatinga domain is very threatened by habitat loss and, for the success of this reintroduction project, the parties involved must act to protect the species and the resources it uses.

Evaluación de los Sitios de Reintroducción de Especies con base en la Futura Idoneidad Climática para los Recursos Alimenticios Resumen La reintroducción de una especie que se encuentra extinta en vida libre exige precaución pues las localidades de reintroducción pueden estar asociadas con amenazas como la cacería, hábitats de mala calidad y el cambio climático. Éste es el caso para Cyanopsitta spixii (Guacamaya de Spix), que ha estado extinta en vida libre desde el 2000. Los pocos individuos vivos nacieron en cautiverio y se usarán para un proyecto de reintroducción dentro del área original de distribución de la especie: el dominio Caatinga (Brasil). Ya que los registros de la presencia de esta ave son viejos e imprecisos, investigamos la idoneidad ambiental actual y a futuro de 14 especies de plantas que C. spixii usa como recurso. Estas plantas son elementos importantes para el restablecimiento a largo plazo de las especies en vida silvestre, así que el uso de modelos asiste en la evaluación de los efectos del cambio climático sobre la disponibilidad de recursos para la especie e informa la selección de los mejores lugares para la reintroducción. Basamos nuestros modelos de la idoneidad ambiental en 19 variables bioclimáticas y 9 variables físicas del suelo y la topografía. Las proyecciones climáticas fueron creadas para el presente y para el año 2070 con un escenario climático optimista (SSP2-4.5) y uno pesimista (SSP5-8.5) Ambos escenarios climáticos futuros llevan a una reducción en el área de idoneidad ambiental sobrepuesta para todas las especies de plantas: 33% de reducción para SSP2-4.5 y 63% de reducción para SSP5-8.5. Si nuestras proyecciones se materializan, el cambio climático podría entonces afectar la distribución de los recursos importantes, por lo que la conservación de C. spixii dependería de la restauración de las áreas degradadas, especialmente los bosques riparios y la preservación de las áreas naturales existentes. El dominio Caatinga se encuentra muy amenazado por la pérdida del hábitat y, para el éxito de este proyecto de reintroducción, las partes involucradas deben actuar para proteger a la especie y los recursos que utiliza.

An estimate of the number of tropical tree species.

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

Floristic units and their predictors unveiled in part of the Atlantic Forest hotspot: implications for conservation planning.

We submitted tree species occurrence and geoclimatic data from 59 sites in a river basin in the Atlantic Forest of southeastern Brazil to ordination, ANOVA, and cluster analyses with the goals of investigating the causes of phytogeographic patterns and determining whether the six recognized subregions represent distinct floristic units. We found that both climate and space were significantly (p ≤ 0.05) important in the explanation of phytogeographic patterns. Floristic variations follow thermal gradients linked to elevation in both coastal and inland subregions. A gradient of precipitation seasonality was found to be related to floristic variation up to 100 km inland from the ocean. The temperature of the warmest quarter and the precipitation during the coldest quarter were the main predictors. The subregions Sandy Coastal Plain, Coastal Lowland, Coastal Highland, and Central Depression were recognized as distinct floristic units. Significant differences were not found between the Inland Highland and the Espinhaço Range, indicating that these subregions should compose a single floristic unit encompassing all interior highlands. Because of their ecological peculiarities, the ferric outcrops within the Espinhaço Range may constitute a special unit. The floristic units proposed here will provide important information for wiser conservation planning in the Atlantic Forest hotspot.

Human impacts affect tree community features of 20 forest fragments of a vanishing neotropical hotspot.

The loss in forest area due to human occupancy is not the only threat to the remaining biodiversity: forest fragments are susceptible to additional human impact. Our aim was to investigate the effect of human impact on tree community features (species composition and abundance, and structural descriptors) and check if there was a decrease in the number of slender trees, an increase in the amount of large trees, and also a reduction in the number of tree species that occur in 20 fragments of Atlantic montane semideciduous forest in southeastern Brazil. We produced digital maps of each forest fragment using Landsat 7 satellite images and processed the maps to obtain morphometric variables. We used investigative questionnaires and field observations to survey the history of human impact. We then converted the information into scores given to the extent, severity, and duration of each impact, including proportional border area, fire, trails, coppicing, logging, and cattle, and converted these scores into categorical levels. We used linear models to assess the effect of impacts on tree species abundance distribution and stand structural descriptors. Part of the variation in floristic patterns was significantly correlated to the impacts of fire, logging, and proportional border area. Structural descriptors were influenced by cattle and outer roads. Our results provided, for the first time, strong evidence that tree species occurrence and abundance, and forest structure of Atlantic seasonal forest fragments respond differently to various modes of disturbance by humans.

Novelties from the herbaceous stratum in a key region for the conservation of the Southern Amazon / Novidades do estrato herbáceo em uma região chave para a conservação da Amazônia Meridional

Abstract The contribution of the herbaceous stratum to tropical plant diversity is considerable, however this component remains undersampled. We investigated floristic, structural, ecological and conservation issues concerning the herbaceous component of a seasonal deciduous forest associated with granitic rock outcrops in the Cristalino Region, a key area for biodiversity conservation in the Brazilian Amazon. We installed a permanent plot of 1 ha, allocating 10 transect-lines of 20 m each. We identified the sampled individuals, measured height and projection, and verified cover and frequency per species, genera and family. We recorded 86 species, 62 genera and 25 families, with Orchidaceae being the family with the highest species richness. Among the 26 new species added to Cristalino Flora, we included Philodendron deflexum Poepp. ex Schott and Griffinia nocturna Ravenna, the latter 'Critically Endangered'. Furthermore, the occurrence of G. nocturna in an Amazonian forest matrix is a novelty in this study. The estimate of species diversity according to Shannon-Wiener (H') was 2.43 nats.ind.-1 (equivalent to 11.37 ± 0.90 IC95% equally common species), and according to Simpson (1/D), 6.82 (± 0.648 IC95%). The rarefaction and extrapolation curves for the diversity estimates tended to stabilize. Although the vegetation on rock outcrops usually presents a high number of endemic species, this pattern was not found in our study area, which can be explained by its continuous occurrence in the forest matrix. The understory of our study area consists in a mixture of floras, being composed mainly of species from the Amazon and/or Cerrado biomes. In view of the current anthropic pressure faced by the southern Amazon, we reinforce the importance of carrying out inventories of its herbaceous communities, since the risk of species loss is even more alarming when considering present undersampling of this component.

Resumo A contribuição do estrato herbáceo para a diversidade de plantas tropicais é considerável, mas esse componente permanece subamostrado. Investigamos questões florísticas, estruturais, ecológicas e de conservação relacionadas ao componente herbáceo de uma floresta estacional decidual associada a afloramentos rochosos graníticos na região do Cristalino, que é uma área chave para a conservação da biodiversidade na Amazônia brasileira. Instalamos um plot permanente de 1 ha, alocando 10 linhas de 20 m cada. Identificamos os indivíduos amostrados, medimos altura e projeção e verificamos cobertura e frequência por espécie, gênero e família. Registramos 86 espécies, 62 gêneros e 25 famílias, sendo Orchidaceae a família com maior riqueza de espécies. Entre as 26 novas espécies adicionadas à Flora do Cristalino, incluímos Philodendron deflexum Poepp ex Schott e Griffinia nocturna Ravenna, esta última 'Criticamente Ameaçada'. Além disso, a ocorrência de G. nocturna em uma matriz florestal amazônica é uma novidade neste estudo. A estimativa da diversidade de espécies de acordo com Shannon-Wiener (H ') foi 2,43 nats / ind.-1 (equivalente a 11,37 ± 0,90 IC95% espécies igualmente comuns), e de acordo com Simpson (1/D), 6,82 (± 0,648 IC95%). As curvas de rarefação e extrapolação para as estimativas de diversidade tenderam à estabilização. Embora a vegetação associada a afloramentos rochosos em geral apresente um elevado número de espécies endêmicas, esse padrão não foi encontrado para a nossa área de estudo, o que pode ser explicado pela sua ocorrência contínua à matriz florestal. O sub-bosque da nossa área de estudo apresenta mistura de floras, sendo composto principalmente por espécies dos biomas Amazônia e/ou Cerrado. Diante das pressões antrópicas existentes no sul da Amazônia, reforçamos a importância da realização de inventários das comunidades herbáceas desse bioma, já que o risco de perda de espécies é ainda mais alarmante quando consideramos a subamostragem desse componente.

Woody vegetation associated with rocky outcrops in Southern Amazonia: a starting point to unveil a unique flora / Vegetação lenhosa associada a afloramentos rochosos na Amazônia Meridional: um marco inicial que revela uma flora única

Abstract: Vegetation associated with rocky outcrops is responsible for increasing floristic and landscape diversity, since its flora can be different from the adjacent landscape. Our objective was to characterize the woody vegetation associated with the rocky outcrop of the RPPN Mirante da Serra, Cristalino region, Mato Grosso State, Brazil. In a Deciduous Seasonal Forest associated with granite outcrops, we demarcated a plot of 1ha. We performed collections on this plot, installed for conducting monitoring studies, and also random collections on trails near the plot to better represent the outcrop flora. We totaled 126 species, 95 genera and 39 families. Overall, 18 species were increased to the Flora of Cristalino - with seven new records to the flora of Mato Grosso and four new records to the Amazon Domain. We found two threatened and 17 Brazilian endemic species. The rocky outcrop present in the RPPN Mirante da Serra is an important conservation area for a continuous execution of floristic studies in a manner to enable a monitoring program of the area, considering the new occurrence records and also because it contains threatened species.

Resumo: A vegetação que se associa a afloramentos rochosos é responsável por incrementar a diversidade florística e de paisagens, uma vez que a flora pode ser distinta da paisagem circundante. Nosso objetivo foi caracterizar a vegetação lenhosa sobre o afloramento rochoso da RPPN Mirante da Serra, região do Cristalino, estado de Mato Grosso, Brasil. Em uma Floresta Estacional Decidual associada a afloramento granítico, demarcamos uma parcela de 1 ha. Realizamos coletas nesse plot, instalado para a realização de estudos de monitoramento e, ainda, coletas aleatórias em trilhas próximas da parcela para melhor representar a flora do afloramento. A amostragem resultou em um total de 126 espécies, 95 gêneros e 39 famílias. Ao todo, 18 espécies foram incrementadas à Flora do Cristalino, das quais sete são novos registros à flora do estado de Mato Grosso e quatro ao Domínio da Amazônia. Encontramos duas espécies ameaçadas e 17 endêmicas do Brasil. O afloramento rochoso presente na RPPN Mirante da Serra é uma importante área de conservação para uma contínua realização de estudos florísticos de modo a possibilitar um programa de monitoramento da área, considerando os novos registros de ocorrência e, também, por conter espécies ameaçadas.

Identity and relationships of the Arboreal Caatinga among other floristic units of seasonally dry tropical forests (SDTFs) of north-eastern and Central Brazil.

The tree species composition of seasonally dry tropical forests (SDTF) in north-eastern and central Brazil is analyzed to address the following hypotheses: (1) variations in species composition are related to both environment (climate and substrate) and spatial proximity; (2) SDTF floristic units may be recognized based on peculiar composition and environment; and (3) the Arboreal Caatinga, a deciduous forest occurring along the hinterland borders of the Caatinga Domain, is one of these units and its flora is more strongly related to the caatinga vegetation than to outlying forests. The study region is framed by the Brazilian coastline, 50th meridian west and 21st parallel south, including the Caatinga Domain and extensions into the Atlantic Forest and Cerrado Domains. Multivariate and geostatistic analyses were performed on a database containing 16,226 occurrence records of 1332 tree species in 187 georeferenced SDTF areas and respective environmental variables. Tree species composition varied significantly with both environmental variables and spatial proximity. Eight SDTF floristic units were recognized in the region, including the Arboreal Caatinga. In terms of species composition, its tree flora showed a stronger link with that of the Cerrado Dry Forest Enclaves. On the other hand, in terms of species frequency across sample areas, the links were stronger with two other units: Rock Outcrops Caatinga and Agreste and Brejo Dry Forests. There is a role for niche-based control of tree species composition across the SDTFs of the region determined primarily by the availability of ground water across time and secondarily by the amount of soil mineral nutrients. Spatial proximity also contributes significantly to the floristic cohesion of SDTF units suggesting a highly dispersal-limited tree flora. These units should be given the status of eco-regions to help driving the conservation policy regarding the protection of their biodiversity.