Herbivory and leaf expansion of Cyathea phalerata Mart (Cyatheaceae) in subtropical Atlantic Forest, southern Brazil / Herbivoria e expansão foliar de Cyathea phalerata Mart. (Cyatheaceae) em Floresta Atlântica subtropical no sul do Brasil

Herbivory is an interaction with great impact on plant communities since relationships between herbivores and plants are fundamental to the distribution and abundance of species over time and space. The aim of this study was to monitor the rate of leaf expansion in the tree fern Cyathea phalerata and evaluate the damage caused by herbivores to leaves of different ages and whether such damage is related to temperature and precipitation. The study was performed in a subtropical Atlantic Forest fragment located in the municipality of Caraá, in the northeast hillside of Rio Grande do Sul state, in southern Brazil. We monitored 24 mature individuals of C. phalerata with croziers in a population of approximately 50 plants. Leaf expansion rate, percentage of damaged leaves and leaf blade consumption rate by herbivory were calculated. Monthly means for temperature and accumulated rainfall were calculated from daily data. Croziers of C. phalerata were found to expand rapidly during the first and second months after emergence (3.98 cm day-¹; 2.91 cm day-¹, respectively). Damage caused by herbivory was observed in all of the monitored leaves, but none of the plants experienced complete defoliation. The highest percentage (57%) of damaged leaves was recorded at 60 days of monitoring, and also the highest monthly consumption rate of the blade (6.04%) occurred with young, newly-expanded leaves, while this rate remained between 1.50 and 2.21% for mature leaves. Rates of monthly leaf consumption and damaged leaves showed positive and strong relationship with each other and with temperature. The rapid leaf expansion observed for C. phalerata can be considered a phenological strategy to reduce damage to young leaves by shortening the developmental period and accelerating the increase of defenses in mature leaves.

A herbivoria é uma interação de grande impacto sobre as comunidades de plantas, uma vez que as relações entre herbívoros e plantas são fundamentais para a distribuição e abundância das espécies ao longo do tempo e do espaço. O objetivo deste estudo foi monitorar a taxa de expansão foliar da samambaia arborescente Cyathea phalerata e avaliar o dano causado por herbívoros a folhas de diferentes idades, assim como verificar se este dano está relacionado à temperatura e à precipitação. O estudo foi realizado em um fragmento de Floresta Atlântica subtropical localizado no município de Caraá, na encosta nordeste do estado do Rio Grande do Sul, no sul do Brasil. Nós monitoramos 24 indivíduos maduros de C. phalerata com báculos em uma população de aproximadamente 50 plantas. A taxa de expansão foliar, a porcentagem de folhas danificadas e a taxa de consumo da lâmina foliar por herbivoria foram calculados. Médias mensais de temperatura e precipitação acumulada foram calculadas a partir de dados diários. Báculos de C. phalerata expandiram rapidamente durante o primeiro e o segundo mês após emergência (3,98 cm dia-¹; 2,91 cm dia-¹, respectivamente). O dano causado por herbivoria foi observado em todas as folhas monitoradas, mas nenhuma das plantas sofreu desfolhação completa. A maior porcentagem (57%) de folhas danificadas foi registrada aos 60 dias de monitoramento, e também a maior taxa de consumo mensal (6,04%) ocorreu em folhas jovens, recém expandidas, enquanto esta taxa permaneceu entre 1,50 e 2,21% em folhas maduras. As taxas mensais de consumo da lâmina foliar e de folhas danificadas mostraram relação positiva e forte entre si e com a temperatura. A rápida expansão foliar observada em C. phalerata pode ser considerada uma estratégia fenológica para reduzir o dano a folhas jovens, abreviando o período de desenvolvimento e acelerando o aumento das defesas em folhas maduras.

Morfogénesis de la fase sexual de los helechos epífitos Microgramma mortoniana y Pleopeltis macrocarpa (Polypodiaceae) de la Reserva Natural Punta Lara, Buenos Aires, Argentina / Sexual morphogenesis phase of the epiphytic ferns Microgramma mortoniana and Pleopeltis macrocarpa (Polypodiaceae) from Punta Lara Natural Reserve, Buenos Aires, Argentina

Resumen Pleopeltis macrocarpa y Microgramma mortoniana son dos helechos epífitos de la familia Polypodiaceae hallados con baja frecuencia en la Reserva Natural Punta Lara (Buenos Aires, Argentina). El objetivo de este trabajo fue estudiar la morfogénesis de gametófitos epífitos para fortalecer poblaciones vulnerables y contribuir a su conservación. Se recolectaron hojas fértiles. Las esporas se sembraron en placas de Petri con medio de cultivo Dyer. Las esporas se caracterizaron por ser monoletes, elipsoidales, amarillentas y con ornamentación verrucosa. La germinación fue del tipo Vittaria y el desarrollo del gametofito es del tipo Drynaria. El esporofito de P. macrocarpa surgió a los 500 días y el de M. mortoniana a los 120. El patrón de germinación, el desarrollo del gametofito, el glóbulo lipídico en la célula protálica y los pelos unicelulares capitados en el margen podrían considerarse en la sistemática del grupo. La demora en la formación de esporofitos a través de la reproducción sexual, permite inferir que el éxito de su propagación estaría sujeto a la reproducción vegetativa.

Abstract The Punta Lara Natural Reserve is located on the riverside of the La Plata River in the province of Buenos Aires, Argentina. It is the Southernmost relict in the world of subtropical riparian forest. The epiphytic ferns studied in this work belong to the Polypodiaceae family: Microgramma mortoniana and Pleopeltis macrocarpa. Plant communities are subject to high levels of anthropization and introduction of exotic species. The goals of this work are to provide information on the morphogenesis of epiphytic gametophytes and to extend knowledge of their life cycles, contributing to their conservation. Sowing was carried out in Dyer medium. In both species the spores are monolete, ellipsoidal, yellowish and with verrucate sculpture. The equatorial diameter is 60-61 μm, the polar diameter is 39-42 μm. The germination is the Vittaria type; in M. mortoniana occurs at 20 days, while in P. macrocarpa occurs at six days. The filaments are uniseriate of 3-6 cells in length. The gametophyte development is Drynaria type. The cordated form is given after 40 days. In M. mortoniana, buds originated after 40 days. In P. macrocarpa, after 120 days, clathrate trichomes scale-like appear mainly on the margins of the gametophyte. The gametangia are typical of leptosporangiate ferns. The sporophyte of M. mortoniana emerged after 120 days and that of P. macrocarpa arose after 500 days, its blades are simple, spatulate and unicellular and multicellular branching hairs were observed. The germination pattern, gametophyte development, the presence of a lipid globule in the prothalic cell and the formation of unicellular capitated hairs are relevant characters that could be considered for systematic group. The delay in the formation of sporophytes through sexual reproduction, allows us to infer that the success of their establishment in situ would be given by the vegetative reproduction through creeping rhizomes and buds of gametophytes. Rev. Biol. Trop. 66(3): 1078-1089. Epub 2018 September 01.

Lianas, tree ferns and understory species: indicators of conservation status in the Brazilian Atlantic Rainforest remnants, southeastern Brazil / Lianas, fetos arborescentes e espécies de sub-bosque: indicadores do estado de conservação da Mata Atlântica brasileira

Abstract Indicators are applied faster and at lower costs than conventional surveys, providing quick and efficient responses that can facilitate protected areas management. Our aim was to select indicators from vegetation to monitor protected areas. For this purpose, we analyzed understory and quantified lianas and tree ferns in protected and non-protected areas, in order to find indicator species. Our study areas are located in Vale do Ribeira, southeastern São Paulo state, Brazil. One of the areas is under two protection categories (IUCN's categories II and V), and the other is a privately owned farm. Lianas with large diameters (> 13 cm) and tree ferns with great heights (> 19 m) were considered indicators of undisturbed areas (protected areas) because their growth is directly related to forest successional stage. Indicator species within the protected area were shade tolerant species, such as Bathysa australis (A.St.-Hil.) K.Schum., whereas outside the protected area were pioneer species, such as Pera glabrata (Schott) Poepp. ex Baill. e Nectandra oppositifolia Ness. All of the suggested indicators can be used in management actions, especially in protected areas, to guarantee forest maintenance and ensure fulfillment of the conservation objectives of these areas.

Resumo Os indicadores são aplicados com menores custos e mais rapidez em comparação com levantamentos convencionais, fornecendo respostas rápidas e eficientes que podem facilitar a gestão das áreas protegidas. Nosso objetivo foi selecionar indicadores de vegetação para monitorar áreas protegidas. Para este fim, analisamos o sub-bosque e quantificamos as lianas e fetos arborescentes em áreas protegidas e não-protegidas em busca de espécies indicadoras. Nossas áreas de estudo estão localizadas na região do Vale do Ribeira, sudeste do Estado de São Paulo, Brasil. Uma delas é uma área protegida (categorias da IUCN II e V) e outra uma fazenda de propriedade privada. Lianas com grandes diâmetros (>13 cm) e fetos arborescentes com grandes alturas (>19 m) foram considerados indicadores de áreas não perturbadas (área protegida), pois seu crescimento está diretamente associado com o estágio sucessional das florestas. As espécies indicadoras da área protegida são não pioneiras, como Bathysa australis (A.St.-Hil.) K.Schum., já as da fazenda (não protegida) são pioneiras, como Pera glabrata (Schott) Poepp. ex Baill. e Nectandra oppositifolia Ness. Todos indicadores sugeridos podem ser utilizados em ações de gestão e conservação, especialmente em áreas protegidas, para garantir a manutenção dos remanescentes florestais e para assegurar o cumprimento dos objetivos destas áreas.

Coleoptera associated with macrophytes of the genus Salvinia in four oxbow lakes in two river basins in southeast Brazil / Coleoptera associados à Salvinia em quatro lagoas marginais pertencentes a duas bacias hidrográficas no estado de São Paulo, Brasil

Abstract Macrophytes in oxbow lakes represent an important substrate for the Coleoptera. Two oxbow lakes the Rio Paranapanema were studied and the other two Rio Mogi-Guaçu, in the State de São Paulo, Brasil. In this study, there is greater similarity between the communities of Coleoptera of lakes greater connectivity with the main river channel or the difference in the species of Salvinia collected in the lakes studied interferes Coleoptera fauna that uses as substrate. A total of 9,222 specimens of Coleoptera were collected and identified in 10 families and 40 genera. The analysis MDS for abundance of Coleoptera showed the grouping of the oxbow lakes the Paranapanema River and a distancing the oxbow lakes the Mogi-Guaçu. The PERMANOVA test did not reveal any difference in the fauna between the wet and dry periods. It was concluded that the connectivity between river and lake is not decisive for the richness and abundance of aquatic fauna of Coleoptera. Therefore, the richness and abundance of aquatic Coleoptera associated vary with the species of Salvinia used as substrate.

Resumo As macrófitas em lagoas marginais constituem um importante substrato para os Coleoptera. Foram estudadas duas lagoas marginais ao Rio Paranapanema e outras duas ao Rio Mogi-Guaçu, no estado de São Paulo, Brasil. Neste estudo, haverá maior similaridade entre as comunidades de Coleoptera das lagoas de maior conectividade com o canal princial do rio ou a diferença na espécie de Salvinia coletada nas lagoas estudadas interfere na fauna de Coleoptera que a utiliza como substrato. Foram coligidos 9.222 espécimes de Coleoptera sendo identificadas 10 famílias e 40 gêneros. A análise MDS para abundância de Coleoptera mostrou o agrupamento das lagoas marginais ao Rio Paranapanema e um distanciamento das lagoas marginais ao Rio Mogi-Guaçu. Os resultados da análise PERMANOVA não mostraram diferença na composição faunística entre os períodos de chuva e seca. Concluiu-se que a conectividade entre rio e lagoa não é determinante para a riqueza e abundância da fauna de Coleoptera aquáticos. Portanto, a riqueza e a abundância de Coleoptera aquáticos associados variam com as espécies de Salvinia utilizadas como substrato.

A simple technique for tracking individual spore and gametophyte development in Adiantum lunulatum Burm. f. using modified extra thin alginate film technique.

A new technique was developed for accurate calculation of percent germination and tracking of individual spores from germination to gametophyte development in Adiantum lunulatum. High percentage of ETAF immobilized spore germination (72.4%) was followed by development of gametophytic clumps. The ETAF immobilized clumps were cut into pieces and multiplied en masse. Apomictic sporophytes developed from the gametophytes. This indicated the potential of ETAF for mass propagation of A. lunulatum without the need to start from spores. Since individual spores can be tracked from germination to gametophyte development, the ETAF technique has the potential to be used for (i) harvesting uniformly developed plants of similar age for extensive experimentations and commercial utilization and (ii) detailed study on developmental and reproductive biology of different ferns and fern allies.

In vitro propagation of Cyathea atrovirens (Cyatheaceae): spore storage and sterilization conditions / Propagación in vitro de Cyathea atrovirens (Cyatheaceae): almacenamiento de esporas y condiciones de esterilización

Cyathea atrovirens occurs in a wide range of habitats in Brazil, Paraguay, Uruguay and Argentina. In the Brazilian State of Rio Grande do Sul, this commonly found species is a target of intense exploitation, because of its ornamental characteristics. The in vitro cultura is an important tool for propagation which may contribute toward the reduction of extractivism. However, exogenous contamination of spores is an obstacle for the success of aseptic long-term cultures. This study evaluated the influence of different sterilization methods combined with storage conditions on the contamination of the in vitro cultures and the gametophytic development of C. atrovirens, in order to establish an efficient propagation protocol. Spores were obtained from plants collected in Novo Hamburgo, State of Rio Grande do Sul, Brazil. In the first experiment, spores stored at 7oC were surface sterilized with 0.5, 0.8 and 2% of sodium hypochlorite (NaClO) for 15 minutes and sown in Meyer’s culture medium. The cultures were maintained in a growth room at 26±1ºC for a 12-h photoperiod and photon flux density of 100μmol/m²/s provided by cool white fluorescent light. Contamination was assessed at 60 days, and gametophytic development was scored at 30, 60, 120 and 130 days of in vitro culture, analyzing 300 individuals for each treatment. There was no significant difference in culture contamination among the different sodium hypochlorite concentrations tested, and all treatments allowed for the development of cordiform gametophytes at 130 days of culture. In the second experiment, spores stored at 7 and -20°C were divided into two groups. Half of the spores were surface sterilized with 2% of NaClO for 15 minutes and the other half was not sterilized. All spores were sown in Meyer’s medium supplemented with one of the following antibiotics: nystatin, Micostatin® and actidione. The culture conditions and the procedures used for evaluating contamination and gametophytic development were the same described for the first experiment. No contamination was observed in spores stored at -20°C and treated with NaClO and actidione. In all treatments, cordiform gametophytes presenting antheridia were observed at 120 days. The percentages of these gametophytes increased from 120 to 130 days and no significant differences were observed among treatments. Archegonia were observed on cordiform gametophytes at 130 days. The findings provide data relevant to in vitro propagation procedures of this species, which may increase the availability of plants for ornamental purposes, therefore contributing to the reduction of the exploitation of endangered tree ferns species. Rev. Biol. Trop. 62 (1): 299-308. Epub 2014 March 01.

Cyathea atrovirens (Langsd. & Fisch.) Domin (Cyatheaceae) se presenta en una amplia gama de hábitats en Brasil, Paraguay, Uruguay y Argentina. Debido a sus características ornamentales, la especie es objeto de intensa explotación. El cultivo in vitro es una herramienta importante para la propagación lo que puede contribuir a la reducción del impacto de las actividades extractivas. Sin embargo, la contaminación exógena de esporas es un obstáculo para el éxito de cultivos asépticos a largo plazo. Este estudio evaluó la influencia de diferentes métodos de esterilización en combinación con las condiciones de almacenamiento sobre la contaminación de los cultivos in vitro y el desarrollo gametofítico de C. atrovirens. En el primer experimento, las esporas almacenadas a 7°C se esterilizaron superficialmente con 0.5, 0.8 y 2% de hipoclorito de sodio (NaClO) durante 15 minutos y se sembraron en medio de cultivo de Meyer. Aunque no hubo diferencia en la contaminación de lós cultivos entre las concentraciones de hipoclorito de sodio de las diferentes pruebas, en el tratamiento con 2% NaClO se observó un mayor porcentaje de gametofitos cordiformes a los 130 días. En el segundo experimento, las esporas almacenadas a 7 y -20°C fueron divididas en dos grupos. La mitad de las esporas se esterilizaron con 2% de NaClO durante 15 minutos y la otra mitad no fue esterilizada. Todas las esporas se sembraron en medio de Meyer suplementado con uno de los siguientes antibióticos: nistatina, Micostatin® o actidiona. No se observó contaminación de las esporas almacenadas a -20°C y tratadas con NaClO y actidiona. En todos los tratamientos, se observaron gametofitos cordiformes con anteridios y arquegonios. Los resultados proporcionan datos relevantes para la propagación in vitro de C. atrovirens, que pueden aumentar la disponibilidad de las plantas para fines ornamentales, contribuyendo así a la reducción de la exploración de las especies de helechos arborescentes en peligro de extinción.

Caudex growth and phenology of Cyathea atrovirens (Langsd. & Fisch.) Domin (Cyatheaceae) in secondary forest, southern Brazil / Crescimento do cáudice e fenologia de Cyathea atrovirens (Langsd. & Fisch.) Domin (Cyatheaceae) em floresta secundária, no sul do Brasil

The leaf production and senescence, formation and release of spores of Cyathea atrovirens (Langsd. & Fisch.) Domin were analysed based on the monthly monitoring of 50 plants growing in a secondary forest, in the municipality of Novo Hamburgo, in the state of Rio Grande do Sul, during the year 2004. The caudex height and number of mature and fertile leaves were recorded annually in 2004-09. In 2004, monthly production and senescence of leaves were concomitant, without total leaf abscission. Population synchrony at emergence (Z = 0.86) and leaf senescence (Z = 0.82) increased in spring but did not correlate with temperature and photoperiod. All individuals were fertile and the sporangia production and spore liberation presented higher and equal synchrony (Z = 0.84) respectively in spring and summer. Sporangia production was related with temperature and photoperiod, however taller plants did not produce more fertile leaves. Phenological events analysed were not influenced by precipitation, as expected for forests in non-seasonal climate. Over five years (2004-09), the annual mean caudex growth varied between 1.19 and 2.50 cm.year-1 and the plants appeared to have an ability to maintain a relatively stable amount of leaves throughout this period.

A produção e a senescência de folhas, a formação e a liberação de esporos de Cyathea atrovirens (Langsd. & Fisch.) Domin, durante o ano de 2004, foram analisadas a partir do monitoramento mensal de 50 plantas, crescendo em floresta secundária, no município de Novo Hamburgo, Estado do Rio Grande do Sul, Brasil. A altura do cáudice e o número de folhas foram mensurados anualmente de 2004-2009. Em 2004, a produção e a senescência mensal de folhas foram concomitantes, evitando a abscisão foliar total. A sincronia da população na renovação (Z = 0,86) e na senescência foliar (Z = 0,82) aumentou na primavera, porém esses eventos não se relacionaram com temperatura e fotoperíodo. Todos os indivíduos estavam férteis e a produção de esporângios e a liberação de esporos apresentaram uma sincronia maior e igual (Z = 0,84), respectivamente, na primavera e no verão. A produção de esporângios se relacionou com temperatura e fotoperíodo, porém plantas mais altas não produziram mais folhas férteis. Os eventos fenológicos analisados não foram influenciados pela precipitação, tal como esperado para florestas sob clima não sazonal. Durante cinco anos (2004-2009), a média anual do crescimento do cáudice variou de 1,19 a 2,50 cm.ano-1 e as plantas demonstraram capacidade de manter o número de folhas relativamente estável ao longo do período.

Edge effects on fern community in an Atlantic Forest remnant of Rio Formoso, PE, Brazil / Efeitos de borda na comunidade de samambaias em um remanescente de Floresta Atlântica de Rio Formoso, PE, Brasil

We have investigated how edge effects influence the fern community of Jaguarão Forest (08º 35' 49" S and 35º 15' 39" W), located in the district of Rio Formoso, Pernambuco, Brazil. A comparative analysis was made of the interior and edge of the fragment of forest, regarding the richness, abundance and diversity of ferns in the two areas. Six plots of 10 × 20 m were chosen, three in each area. A total of 381 ferns were recorded, which were distributed among 25 species, 17 genera and 12 families. The two areas (edge and interior) were found to differ, with distinct relative air humidities and temperatures (p = 0.00254 and p = 0.00019, respectively). The interior showed higher diversity (t = 7.251 and p = 0.018) and richness (t = 6.379 and p = 0.023) than the edge area, but the same abundance (t = 1.728; p = 0.226) as the edge. Regarding the composition of the flora, it was clear that the interior is a habitat completely distinct from the edge with regard to the fern community, given that only one species, Adiantum petiolatum Desv., was common to both environments. It was concluded that the edge effect causes a decrease in richness and abundance of the fern species found in Jaguarão Forest, where the more sensitive species are being replaced by species that are tolerant to the disturbance caused by the creation of an edge.

Este trabalho verificou como os efeitos de borda influenciam as comunidades de pteridófitas presentes na Mata do Jaguarão (08º 35' 49" S e 35º 15' 39" W), município de Rio Formoso, Pernambuco. O estudo foi feito através de análise comparativa entre os ambientes de interior e de borda. Para verificar a riqueza, abundância e diversidade das pteridófitas nos dois ambientes, foram estabelecidas seis parcelas de 10 × 20 m (200 m²), sendo três para cada ambiente. Foram contabilizados 381 indivíduos de pteridófitas, distribuídos em 25 espécies, 17 gêneros e 12 famílias. Os dois ambientes (interior e borda) caracterizaram-se diferentes entre si, com umidade relativa do ar e temperatura distintas (p = 0,00254 e p = 0,00019, respectivamente). O ambiente de interior apresentou maior diversidade (t = 7,251 e p = 0,018) e riqueza (t = 6,379 e p = 0,023) que o ambiente de borda, de acordo com o teste estatístico empregado (teste t pareado). A abundância, por outro lado, foi a mesma em interiores e bordas do fragmento (t = 1,728 e p = 0,226). Quanto à composição florística, ficou claro que o interior do fragmento estudado constitui um ambiente totalmente distinto da borda, no que se refere à comunidade pteridofítica, com apenas uma espécie comum aos dois ambientes, Adiantum petiolatum Desv. Assim, o presente estudo constatou que o efeito de borda causa diminuição na riqueza e abundancia das espécies de pteridófitas ocorrentes na Mata do Jaguarão, com a existência de substituição das espécies mais sensíveis pelas espécies tolerantes aos impactos causados por esse efeito.

Sporophyte morphology and gametophyte development of the fern Blechnum sprucei (Pteridophyta: Blechnaceae)

The fern Blechnum sprucei grows in Mesoamerica (Costa Rica) and South America, from Colombia to Bolivia, SE and centre of Brazil, Paraguay and Argentina. It is a distinctive, somewhat vulnerable, mostly orophilous species. Fresh and dry herbarium material was used for this study. Herbarium material for anatomical studies comes from CTES, BA, LP, MA, SI and UC (Holmgren et al.1990). Selected representative specimens are additionally cited after taxonomic treatment of the species. Dry material was restored with aqueous 4:1 butil cellosolve. Pinnae were cleared with aqueous 6% NaOH, then coloured with aqueous 1 % TBO (Gurr 1966). Hand made transverse sections of young and adult stipes, and costae were done in fresh and restored herbarium material. Venation and epidermal patterns were analyzed in basal, apical and medium pinnae, but only the latter were illustrated. The size and density of stomata were measured in medium pinnae from all studied samples, values shown are the average of 25 measures per sample; sizes are expressed as minimum, media and maximum length x width, in µm, and density as minimum, media and maximum number of stomata / mm². Spores were studied with SEM, mounted on metal stubs with double sided tape, covered with gold under vacuum and photographed with a Jeol /EO JSM 6360 (15 KV) SEM. Spores were also studied with light microscope, mounted in DePex (DePex mounting medium, Gurr, BDH Laboratory Supplies, Poole BH15 1TD, UK) and measured using an ocular micrometer. Measurements are based on a minimum sample of 100 spores taken from different specimens. Sizes are expressed as the longest equatorial diameter/ polar diameter, in µm. Gametophytes were studied from material collected in the subtropical forest of Tucumán Province, Argentina. Spore samples for cultures were taken from single sporophytes kept dry at room temperature since the date plants were collected. Gametophytes were grown under fluorescent light. Multispore cultures were established on mineral agar. Percentage of germination was recorded for a random sample of 50 spores from each of the two plates, every three days until there was no further increasing. Gametophytes were stained with chloral hydrate acetocarmine. The species has large sporophytes, suberect, scaly rhizomes, and dimorphic fronds with short, scaly stipes and lanceolate to elliptic sterile laminae. The rachises can grow indefinitely as radicant axis that vegetatively multi-plicate the plants. Pinnae are lanceolate, herbaceous, with crenate and papillose margins, superficially scaly and hairy, peciolulate, with free, visible veins regularly once furcated near the costa, ending in large, active hydathodes. The broadly elliptic fertile laminae bear distant pinnae, with vegetative tissue reduced to the portion that supports the indusium and the continuous coenosorus; terminal indefinite rachis, not proliferous, may be present. Rev. Biol. Trop. 56 (4): 2027-2040. Epub 2008 December 12.

El helecho Blechnum sprucei crece en Mesoamérica (Costa Rica) y Sudamérica, desde Colombia a Bolivia, SE y centro de Brasil, Paraguay y Argentina. Es una especie característica, algo vulnerable y orófila. Se estudiaron caracteres exomorfológicos de especimenes provenientes de distintos puntos de su gran área de distribución. Adicionalmente, se llevó a cabo un detallado análisis de los modelos epidérmicos jóvenes y maduros, del indumento de la lámina y los ejes, y de la organización vascular en los estipes y costas. Se han estudiado por primera vez la morfología esporal, el desarrollo de los gametófitos, que resultaron cordados y pelosos, y su expresión sexual. Presenta esporófitos grandes, suberectos, con rizomas escamosos y frondas dimórficas, con estipes cortos y escamosos y láminas estériles de lanceoladas a elípticas. El raquis puede crecer indefinidamente como un eje radicante que multiplica las plantas vegetativamente. Las pinnas son lanceoladas, herbáceas, con márgenes crenados y papilosos, y la superficie escamosa y pelosa. Son pecioluladas, con venas libres y visibles, regularmente furcadas cerca de la costa, terminando en hidatodos grandes y activos. Las láminas fértiles son anchamente elípticas y portan pinnas distales; presentan tejido vegetativo reducido a la porción que soporta el indusio y el cenosoro continuo. Pueden presentar raquis indefinidos, pero no prolíferos.

Factors associated with the catastrophic decline of a cloudforest frog fauna in Guatemala

Comparison of recent and historical surveys of frog populations in cloudforest habitat in Sierra de las Minas,Guatemala,indicated population declines and local extirpation of several species.Pathological exams of diseased tadpoles indicated infection by amphibian chytridiomycosis. The local habitat has been severely altered by recent establishment of large-scale leatherleaf fern production.Analysis of water chemistry at our study site suggested increased nitrogenation associated with the leatherleaf industry

Una comparación entre un inventario anterior y otro reciente de poblaciones de ranas de bosque nublado en la Sierra de Las Minas de Guatemala demostró disminuciones poblacionales y ausencia localizada de varias especies.El examen patológico de un renacuajo muerto indicó infección por un hongo quítrido propio de los anfibios.El hábitat local ha sido gravemente alterado por el establecimiento reciente de producción a gran escala de helechos ornamentales.El análisis químico del agua en el área de estudio señaló un aumento en nitrogenación asociado al cultivo de helechos