Estructura de las comunidades de briófitos en los complejos de páramos de Boyacá-Colombia / Structure of bryophyte communities in the paramo complexes of Boyacá-Colombia

Introducción: Los páramos de Boyacá cubren el 18.3 % de la superficie de Colombia, y son diversos en flora y fauna, además, registran una alta variabilidad climática, topográfica y de hábitats, que permite que estos ecosistemas sean centros de diversidad en el Neotrópico, y por tanto albergan una alta diversidad de briófitos. Objetivo: Analizar la estructura y composición de las comunidades de briófitos de los complejos de páramos de Boyacá. Métodos: a partir de información de literatura, bases de datos y revisión de herbarios, se evaluó la composición florística y la completitud de muestreo para los complejos de páramos y sustratos. Resultados: Se encontraron 5 132 ejemplares, con 343 especies de musgos que fue el grupo más diverso, 256 hepáticas y dos antocerotes. El análisis de completitud de muestreo es representativo en un 98 %. Además, encontramos que la preferencia de sustratos es el terrícola con 409 especies y el cortícola con 341. La diversidad alfa del orden 0D mostró que Tota-Bijagual-Mamapacha (TBM) es el complejo más diverso con 368 especies, y Pisba (124) el menos diverso; el índice 1D mostró que el complejo (TBM) presentó 178 especies consideradas comunes, y la dominancia de especies (2D) fue mayor en el complejo Iguaque-Merchán con 119 taxa dominantes y en menor número Guantiva-La Rusia (105) y TBM (102). Conclusiones: El análisis de la diversidad beta mostró que el 62 % de la disimilitud en la composición de especies entre los complejos se debe al recambio de especies, igualmente sucede con la divergencia por sustratos que es del 51 %. Los briófitos en los páramos de Boyacá representan el 36.05 % de la diversidad colombiana, y el 2.96 % a nivel mundial.

Introduction: The Boyacá paramos cover 18.3 % of the Colombian surface, and are diverse in flora and fauna, moreover, have a high temperature, topography, and habitats, which allow these ecosystems to be centers of diversity in the Neotropics, and therefore they harbor a high diversity of bryophytes. Objectives: Analyze the structure and composition of the bryophyte communities of the paramos in the Boyacá complexes. Methods: Using literature, databases and herbariums records, the floristic composition, and the completeness of the sampling for the paramo and substrate complexes was evaluated. Results: We analyzed 5 132 specimens, with 343 species of mosses being the most diverse group, 256 liverworts and two hornworts. The sampling completeness analysis is 98 % representative. In addition, we found that the preference of substrates is terrestrial with 409 species and corticolous with 341. Alpha diversity of order 0D showed that Tota-Bijagual-Mamapacha (TBM) is the most diverse complex with 368 species, and Pisba (124) the least diverse; the 1D index showed that the complex (TBM) presented 178 species considered common, and the dominance of species (2D) was higher in the Iguaque-Merchán Complex with 119 dominant taxa and Guantiva-La Russia (105) and TBM (105) to a lesser number. (102). Conclusions: the analysis of beta diversity showed that 62 % of the dissimilarity in the composition of species between the complexes is due to the species turnover, the same happens with the divergence by substrates that is 51 %. Bryophytes in the Boyacá paramos represent 36.05 % of Colombian diversity, and 2.96 % worldwide.

Vertical distribution of beta diversity of macroinvertebrates in an oligotrophic high mountain neotropical lake / Distribución vertical de la diversidad beta de macroinvertebrados en un lago oligotrófico de alta montaña neotropical

RESUMEN Los componentes alfa (α) y beta (ß) de la diversidad gamma (γ), y la partición de ß en anidamiento y recambio, contribuyen a entender los factores que determinan la diversidad biológica. El objetivo de este estudio fue entender los factores que afectan los cambios espaciales de diversidad de macroinvertebrados en lagos andinos tropicales de alta montaña, a partir del estudio de los componentes de diversidad y la partición de la diversidad ß. Para esto, se realizó un muestreo en noviembre de 2018, en un lago ubicado a 3740 m.s.n.m. Se recolectaron macroinvertebrados bentónicos en 20 sitios distribuidos en las zonas litoral, sublitoral y profunda. In situ, se midieron profundidad, temperatura, pH, conductividad y oxígeno disuelto; se realizaron perfiles verticales de oxígeno y temperatura. Se evaluaron los componentes de riqueza mediante el modelo γ= α +ß. Se realizaron: análisis de regresión entre a y g, análisis de disimilitud a partir de la partición de la diversidad ß en recambio y anidamiento, Escalamiento Multidimensional no Métrico (nMDS) y Porcentaje de Similaridad (Simper). Los resultados mostraron que la diversidad a por sitios y zonas del lago es baja con relación a la diversidad g, y la diversidad ß es alta. Esto indica que los lagos tropicales andinos de alta montaña, a pesar de su pequeño tamaño, son importantes para una alta diversidad de macroinvertebrados. La riqueza taxonómica depende de las variaciones ambientales en los gradientes vertical y horizontal. Sin embargo, estos lagos son vulnerables a tensores naturales y antrópicos como el calentamiento global.

ABSTRACT The alpha (α) and beta (ß) components of gamma (γ) diversity, and the partitioning of ß into nesting and turnover, contribute to understanding the factors that determine biological diversity. The objective of this study was to understand the factors affecting spatial changes in macroinvertebrate diversity in tropical high mountain Andean lakes, from the study of diversity components and beta diversity partitioning. For this, sampling was conducted in November 2018, in a lake located at 3740 m.a.s.l. Benthic macroinvertebrates were collected in 20 sites distributed in littoral, sublittoral and deep zones. In situ, depth, temperature, pH, conductivity and dissolved oxygen were measured; vertical profiles of oxygen and temperature were made. Richness components were evaluated using the γ= α +ß model. Regression analysis between a and g, dissimilarity analysis from the partitioning of beta diversity into turnover and nesting, Non-Metric Multidimensional Scaling (nMDS) and Percent Similarity (Simper) were performed. The results showed that a diversity by sites and lake zones is low relative to g diversity, and ß diversity is high. This indicates that high mountain tropical Andean lakes, despite their small size, are important for high macroinvertebrate diversity. Taxonomic richness depends on environmental variations in gradients vertically and horizontally. However, these lakes are vulnerable to natural and anthropogenic stressors such as global warming.

Temporal variation of bird assemblages in dynamic fluvial wetlands: seasonality and influence of water level and habitat availability

Introduction: Study of temporal variation of bird assemblages may be particularly important in highly dynamic ecosystems as fluvial wetlands to identify the factors that influence and contribute to maintain regional bird diversity. Objective: To study temporal variation in regional bird species composition (i.e. set of species that make up the assemblage) and richness (i.e. species number) and the factors that drive it, and quantify the importance of temporal-beta diversity to sustain bird regional diversity, in the fluvial system of the Middle Paraná River in Argentina. Methods: We sampled birds on a regional scale by performing 16 repeated surveys roughly every 45 days across 2 years (2011-2013) at 60 point counts distributed along the fluvial system. Results: We recorded a total of 162 species and 12 738 detections, with a mean of 72.7 ± 1.9 species and 796.1 ± 41 individuals per survey. Temporal beta diversity accounted for 57 % of regional bird species richness. Bird composition varied seasonally because of the species turnover (and not nestedness) between non-breeding and breeding periods; migrant species contributed to this issue but did not account for all these differences. Difference in bird composition between years was associated primarily to species turnover within non-breeding periods and was related to changes in water levels. Temporal variation in availability of habitats across the regional extent of the fluvial system accounted for the highest proportion of temporal beta diversity. Species richness neither varies seasonally nor was it related to fluctuations in water level or habitats. Conclusions: The climatic seasonality and environmental dynamics of the fluvial system, as a function of water-level fluctuations and of variations in habitat availability, jointly influence regional composition of birds through temporal species turnover. These variations in regional composition were not related to variations in regional species richness. These results show the importance of the natural dynamic of the fluvial system to preserve the processes that maintain the regional assemblage of birds.

Variación temporal de ensambles regionales de aves en humedales fluviales dinámicos: estacionalidad e influencia del nivel de agua y la disponibilidad de hábitat. Introducción: El estudio de la variación temporal de los ensambles de aves es particularmente importante en ecosistemas altamente dinámicos como los humedales fluviales para identificar los factores que influencian y contribuyen al mantenimiento de la diversidad regional. Objetivo: Se estudió la variación temporal de la composición (i.e. conjunto de especies que componen el ensamble) y riqueza (número de especies) regional de aves, junto con los factores que las conducen, y la importancia de la diversidad-beta temporal para mantener la riqueza regional de aves, en el sistema fluvial del río Paraná Medio en Argentina. Metodología: Se muestrearon aves a escala regional mediante la realización de 16 muestreos repetidos aproximadamente cada 45 días durante 2 años (2011-2013) en 60 puntos de conteo distribuidos a lo largo del sistema fluvial. Resultados: Se registraron un total de 162 especies y 12 738 detecciones, con una media de 72.7 ± 1.9 especies y 796.1 ± 41 detecciones por muestreo. La diversidad beta temporal representó el 57 % de la riqueza regional de especies. La composición de aves varió estacionalmente debido al recambio (y no al anidamiento) de especies entre períodos no-reproductivos y reproductivos; la variación temporal de las especies migrantes contribuyó, pero no explicó estas diferencias. La diferencia en la composición de aves entre años fue debido al recambio de especies dentro de los períodos no-reproductivos; ese recambio se relacionó con variaciones en el nivel de agua del río. La variación temporal en la disponibilidad de hábitats a lo largo de la extensión regional del sistema fluvial se asoció con la más alta proporción de diversidad beta temporal. La riqueza de especies no varió estacionalmente ni se relacionó con las fluctuaciones en el nivel del agua o los hábitats. Conclusiones: La estacionalidad climática y la dinámica ambiental del sistema fluvial, en función de las fluctuaciones en el nivel de agua y de las variaciones en la disponibilidad de hábitat, influenciaron conjuntamente la composición regional de aves mediante el recambio temporal de especies. Estas variaciones en la composición regional no se relacionaron con variaciones en la riqueza regional de especies. Estos resultados muestran la importancia de la dinámica natural del sistema fluvial para conservar los procesos que mantienen el ensamble regional de aves.

The impact of edge effect on termite community (Blattodea: Isoptera) in fragments of Brazilian Atlantic Rainforest

Abstract Habitat fragmentation is considered to be one of the biggest threats to tropical ecosystem functioning. In this region, termites perform an important ecological role as decomposers and ecosystem engineers. In the present study, we tested whether termite community is negatively affected by edge effects on three fragments of Brazilian Atlantic Rainforest. Termite abundance and vegetation structure were sampled in 10 transects (15 × 2 m), while termite richness, activity, and soil litter biomass were measured in 16 quadrants (5 × 2 m) at forest edge and interior of each fragment. Habitat structure (i.e. number of tree, diameter at breast height and soil litter biomass) did not differ between forest edge and interior of fragments. Termite richness, abundance and activity were not affected by edge effect. However, differences were observed in the diversity between forest edge and interior as well as in the fragments sampled. The diversity partitioning indicates that species turnover is the determinant process of termite community composition under edge effect. Our results suggest that conservation strategies should be based on the selection of several distinct sites instead of few rich sites (e.g. nesting).

Resumo A fragmentação do habitat é considerada uma das maiores ameaças para o funcionamento do ecossistema tropical. Nesta região, os cupins desempenham um papel ecológico importante como decompositores e engenheiros do ecossistema. No presente estudo, testamos se comunidades de cupins são negativamente afetadas pelo efeito de borda em três fragmentos de Mata Atlântica. Para isso, foram amostrados a abundância de cupins e a estrutura da vegetação em 10 transectos (15 × 2 m), enquanto a riqueza, abundância de cupins e biomassa da serrapilheira foram amostrados em 16 parcelas (5 × 2 m) na borda e no interior de cada um dos três fragmentos. A estrutura do habitat (número de árvores, diâmetro à altura do peito e biomassa da serrapilheira) não diferiu entre a borda e o interior dos fragmentos. A riqueza, abundância e atividade dos cupins também não foram afetados pelo efeito de borda. No entanto, foram observadas diferenças na diversidade entre borda e interior dos fragmentos, bem como nos fragmentos amostrados. O particionamento da diversidade indicou que a substituição de espécies (turnover) é o processo determinante da composição da comunidade de cupins sob efeito de borda. Nossos resultados sugerem que as estratégias de conservação devem ser baseadas na seleção de locais distintos em vez de poucos locais (via processo de aninhamento - nesting).

The impact of edge effect on termite community (Blattodea: Isoptera) in fragments of Brazilian Atlantic Rainforest / O impacto do efeito de borda na comunidade de cupins (Blattodea: Isoptera) em fragmentos de florestas da Mata Atlântica

Abstract Habitat fragmentation is considered to be one of the biggest threats to tropical ecosystem functioning. In this region, termites perform an important ecological role as decomposers and ecosystem engineers. In the present study, we tested whether termite community is negatively affected by edge effects on three fragments of Brazilian Atlantic Rainforest. Termite abundance and vegetation structure were sampled in 10 transects (15 × 2 m), while termite richness, activity, and soil litter biomass were measured in 16 quadrants (5 × 2 m) at forest edge and interior of each fragment. Habitat structure (i.e. number of tree, diameter at breast height and soil litter biomass) did not differ between forest edge and interior of fragments. Termite richness, abundance and activity were not affected by edge effect. However, differences were observed in the β diversity between forest edge and interior as well as in the fragments sampled. The β diversity partitioning indicates that species turnover is the determinant process of termite community composition under edge effect. Our results suggest that conservation strategies should be based on the selection of several distinct sites instead of few rich sites (e.g. nesting).

Resumo A fragmentação do habitat é considerada uma das maiores ameaças para o funcionamento do ecossistema tropical. Nesta região, os cupins desempenham um papel ecológico importante como decompositores e engenheiros do ecossistema. No presente estudo, testamos se comunidades de cupins são negativamente afetadas pelo efeito de borda em três fragmentos de Mata Atlântica. Para isso, foram amostrados a abundância de cupins e a estrutura da vegetação em 10 transectos (15 × 2 m), enquanto a riqueza, abundância de cupins e biomassa da serrapilheira foram amostrados em 16 parcelas (5 × 2 m) na borda e no interior de cada um dos três fragmentos. A estrutura do habitat (número de árvores, diâmetro à altura do peito e biomassa da serrapilheira) não diferiu entre a borda e o interior dos fragmentos. A riqueza, abundância e atividade dos cupins também não foram afetados pelo efeito de borda. No entanto, foram observadas diferenças na diversidade β entre borda e interior dos fragmentos, bem como nos fragmentos amostrados. O particionamento da diversidade β indicou que a substituição de espécies ("turnover") é o processo determinante da composição da comunidade de cupins sob efeito de borda. Nossos resultados sugerem que as estratégias de conservação devem ser baseadas na seleção de locais distintos em vez de poucos locais (via processo de aninhamento - "nesting").

Effect of a major highway on the spatial and temporal variation in the structure and diversity of the avifauna of a tropical premontane rain forest / Efecto de una carretera principal en la variación espacial y temporal en la estructura y la diversidad de la avifauna de un bosque lluvioso tropical premontano

Abstract:Roads immersed in conservation areas will increase in number, size, and traffic over the next decade, and thus, understanding their effects on forest-dependent wildlife is crucial for improving current management practices and reducing the negative impacts of roads on sensitive species. We examined the influence of route 32 (a.k.a. Guápiles Highway) on temporal and spatial changes in the structure of the avifauna of Braulio Carrillo National Park, Costa Rica, a site crossed by this road along 25 km. The highway connects the capital city of San José with the Harbor of Limón in the Caribbean Sea (142 km). Although the road is narrow (12 m in width and comprised by two lanes along most of the route) it services over 1.5 million motor vehicles per year, 12 % are heavy trucks and trailers. We expected the highway to divide the avifauna, and thus to observe significant differences in species structure on opposite sides of the road. We described changes in bird diversity between wet and dry seasons at Las Palmas and Ceibo trails located on opposite sides of the highway (14 point counts per trail), and evaluated how abundance and diversity varied with road distance. Censuses took place during wet and dry seasons from 2002 to 2005. We listed 245 species and 6 035 observations during the 4-yr survey. Rare species dominated the avifauna (65 % of species < 5 observations), and species overlap between trails was high (Sorensen= 71 %; Morisita= 0.96). Species accumulation curves varied little among trails, yielding 190 species. Resident species represented 70 % of observations, followed by elevational (15 %) and long-distance migrants (1-2 %). Understory species were the most abundant (60 %) followed by canopy birds (30 %). Species turnover rate was 55 % between seasons, but species composition between trails remained homogeneous. Overall, birds were avoiding the road (abundance increased away from the road) although other diversity parameters (richness, dominance, Shannon index, and equitability) were not influenced by road proximity. Although the avifauna remained homogeneous on both sides of the road, which did not support the fragmentation hypothesis, the highway reduced the abundance and diversity of specialized understory insectivores associated with primary forests near the road. This highway will expand outside the National Park (from 2 to 4 lanes along 107 km from Río Frío to Limón) in the next years, which will increase traffic volume and road impacts within the Park. Roads are increasing across highly diverse tropical areas justifying the need for management practices based on the identification of sensitive groups. Rev. Biol. Trop. 64 (4): 1383-1399. Epub 2016 December 01.

Resumen:Las carreteras inmersas en áreas de conservación van a aumentar en número, tamaño, y volumen de tráfico en la próxima década, por lo que comprender los efectos de las mismas sobre la fauna dependiente de bosque es crucial para mejorar las prácticas de manejo y reducir los impactos negativos de los caminos sobre las especies más frágiles. Examinamos la influencia de la ruta 32 (conocida como la carretera a Guápiles) sobre los cambios temporales y espaciales en la estructura de la avifauna del Parque Nacional Braulio Carrillo, Costa Rica, el cual es atravesado por esta carretera a lo largo de 25 km. La carretera conecta la ciudad capital de San José con el puerto de Limón en el Caribe (142 km). Aunque la calle es estrecha (12 m de ancho en dos carriles en la mayor parte de la ruta) da servicio a más de 1.5 millones de vehículos por año, 12 % de los cuales es transporte pesado. Esperábamos que la carretera fragmentara a la avifauna, y por lo tanto que hubieran diferencias significativas en la estructura de las especies en lados opuestos de la ruta. Describimos los cambios en la diversidad de aves entre las estaciones secas y húmedas en los senderos Las Palmas y Ceibo situados en lados opuestos de la carretera (14 puntos de conteo por sendero), y evaluamos cómo la abundancia y la diversidad variaron con la distancia hacia la carretera. Los censos se realizaron durante las estaciones húmedas y secas desde el 2002 al 2005. Encontramos 245 especies y 6 035 observaciones durante el período de 4 años. Las especies raras dominaron la avifauna (65 % de las especies < 5 observaciones), y mostraron un alto traslape entre senderos (Sorensen= 71 %; Morisita= 0.96). Las curvas de acumulación de especies variaron poco entre senderos, generando 190 especies. Las especies residentes representaron el 70 % de las observaciones, seguidas migrantes de elevación (15 %) y especies migratorias latitudinales (1-2 %). Las especies de sotobos que fueron las más abundantes (60 %), seguidas por las aves de dosel (30 %). La tasa de recambio de especies fue del 55 % entre estaciones, pero la composición de especies entre senderos permaneció homogénea. El patrón general consistió en que las aves evitaron la carretera (la abundancia aumentó lejos de la carretera), aunque otros parámetros de diversidad (riqueza, dominancia, el índice de Shannon y la equidad) no fueron influenciados por la proximidad de la calle. Si bien los resultados no apoyaron la hipótesis de la fragmentación, la carretera redujo la abundancia y diversidad de insectívoros especializados de sotobosque asociados a bosque primario. Esta carretera se expandirá fuera del Parque Nacional (de 2 a 4 carriles a lo largo de 107 km de Río Frío a Limón) en los próximos años, lo que aumentará el impacto del volumen de tráfico dentro del parque. Las carreteras cercanas a zonas protegidas están aumentando en los trópicos, por lo que es crucial desarrollar alternativas de manejo basadas en la respuesta de los grupos sensibles a estos impactos.

Heterogeneidade do habitat, riqueza e estrutura da assembléia de besouros rola-bostas (Scarabaeidae: Scarabaeinae) em áreas de cerrado na Chapada dos Parecis, MT / Habitat heterogeneity, richness and structure of assemblages of dung beetles (Scarabaeidae: Scarabaeinae) in areas of cerrado in the Chapada dos Parecis, Mato Grosso state, Brazil

Ecological theory of habitat heterogeneity and limited niche-similarity assumes that more heterogeneous environments provide a greater amount and diversity of resources than simple environments, resulting in a greater diversity of species. This study aimed to evaluate the effect of the habitat heterogeneity on the richness of dung beetles and to examine the spatial patterns of assemblage structure in relation to patterns of habitat heterogeneity. Dung beetles were collected using pitfall traps without bait in 30 points distributed in an area of cerrado sensu lato, in the region of Tangará da Serra, MT, Brazil, including areas of cerrado sensu stricto, campo sujo, cerradão and gallery forest. A total of 1,291 dung beetles were collected, distributed in 16 genera and 29 species. Overall habitat heterogeneity exerted a negative effect on patterns of dung beetles richness. Higher levels of species richness were observed in areas of cerrado campo sujo, while the areas of gallery forest were the most species poor. Regarding assembly structure, it was found that the dung beetles were separated into two major groups, one formed by the presence of specialized species in forest areas and other composed of species that occurred predominantly in cerrado. In conclusion, it was found that habitat complexity influenced the distribution of dung beetles, but the level of turnover in species composition along the heterogeneity gradient was relatively weak.