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Echolocation and Stratum Preference: Key Trait Correlates of Vulnerability of Insectivorous Bats to Tropical Forest Fragmentation
Get PDFHabitat loss and fragmentation rank high amongst the most pressing threats to biodiversity. Understanding how variation in functional traits is associated with species vulnerability in fragmented landscapes is central to the design of effective conservation strategies. Here, we used a whole-ecosystem ecological experiment in the Central Amazon to investigate which functional traits of aerial-hawking insectivorous bats best predict their sensitivity to forest fragmentation. During 2014, bats were surveyed using passive bat recorders in six continuous forest sites, eight forest fragments, eight fragment edges, and eight forest clearings. The interaction between functional traits, environmental characteristics, and species distribution was investigated using a combination of RLQ and fourth-corner analyses. Our results showed that echolocation call structure, vertical stratification, and wing aspect ratio were the strongest predictors of sensitivity to forest fragmentation. Frequency of maximum energy, body mass, and relative wing loading did not show any correlation with the environmental variables. Bat species with constant-frequency calls were associated with high vegetation density, being more susceptible to forest fragmentation than species with frequency-modulated calls. Vertical stratum preference was also correlated with vegetation structure, indicating that understory species were more sensitive to forest loss than canopy species. Finally, species with high aspect ratio wings were linked to forest edges and clearings. Our findings suggest that species functional traits determine the vulnerability of aerial-hawking insectivorous bats toward fragmentation and, similarly, environmental conditions determine if a species is likely to become locally extinct due to fragmentation. Preserving structurally complex forests will be crucial to ensure the long-term persistence of the most sensitive and vulnerable species of this bat ensemble in fragmented landscapes across the Neotropics. © Copyright © 2019 Núñez, López-Baucells, Rocha, Farneda, Bobrowiec, Palmeirim and Meyer
Composição e diversidade de mosquitos (Diptera: Culicidae) coletados na área de influência da hidrelétrica do Jirau, Rondônia
No full textEvaluación del potencial alelopático de extractos metanólicos de hongos endofíticos Colletotrichum dianesei y Xylaria sp aislados de Palicourea corymbifera
No full textMARCADORES DE DNA MICROSSATÉLITES PARA Brachyplatystoma filamentosum (SILURIFORMES: PIMELODIDAE): ISOLAMENTO, CARACTERIZAÇÃO E AMPLIFICAÇÃO HETERÓLOGA NO GÊNERO Brachyplatystoma
No full textIs There a Classical Inertial Sublayer Over the Amazon Forest?
No full textOn the basis of measurements over different surfaces, an inertial sublayer (ISL), where Monin-Obukhov Similarity Theory applies, exists above z=3h, where h is canopy height. The roughness sublayer is within h<z<3h. Most studies of the surface layer above forests, however, are able to probe only a narrow region above h. Therefore, direct verification of an ISL above tall forests is difficult. In this study we conducted a systematic analysis of unstable turbulence characteristics at heights from 40 to 325 m, measured at an 80m, and the recently built 325-m Amazon Tall Tower Observatory towers over the Amazon forest. Our analyses have revealed no indication of the existence of an ISL; instead, the roughness sublayer directly merges with the convective mixed layer above. Implications for estimates of momentum and scalar fluxes in numerical models and observational studies can be significant. ©2019. American Geophysical Union. All Rights Reserved
Response of black-water floodplain (igapó) forests to flood pulse regulation in a dammed Amazonian river
No full textThe monomodal flood pulse of major Amazonian rivers is a seasonal phenomenon that determines ecological and biogeochemical processes in adjacent floodplain forests. River damming transforms the pattern of downstream flood pulses and provides a natural disturbance to which the native biota might be poorly adapted. Severe modifications of the flood pulse were recorded in the Uatumã River after the installation of the Balbina dam, Central Amazonia. Flood pulse regulation increased mortality of flood-adapted species in the black-water floodplain (igapó) forest. No previous studies have investigated impacts of flood pulse regulation on the species composition and forest structure of igapó forests. Therefore, we examined species composition and forest structure of igapó forests along a regulated river in comparison to a pristine tributary, the Abacate River, evaluating soil texture characteristics and flood duration. In order to assess potential encroachment of species less sensitive to flood alteration, we also inventoried adjacent non-flooded upland forest in each river section. A quantitative inventory of all trees with diameter at breast height (DBH) ≥5 cm was carried out in low-igapó, high-igapó and adjacent upland forests, totaling one half-hectare in each river. In both rivers investigated, the clay fraction of the soil was significantly related to tree height. Flood duration was correlated to DBH and basal area, with the largest trees found in low-igapó forests which are exposed to long-term flooding. Species composition, richness and diversity significantly responded to flood duration. Species richness was highest in upland forests and lowest in low-igapó forest. In the pristine river, tree species composition exhibited a turnover of species along the flooding gradient. In the regulated river, flood intensification in the low-igapó forest increased dominance of a few flood-adapted species, which produced floristic dissimilarity to all forest types investigated. On the other hand, high-igapó forest showed higher floristic similarity with upland forest due to flood suppression that contributed to encroachment of species commonly described in secondary upland forests. Our results emphasize the urgent need for Brazilian environmental regulatory agencies to incorporate downstream impacts in the environmental assessments of dam projects in the Amazon Basin. © 2018 Elsevier B.V
Impacto da presença de rios e área urbana no desenvolvimento de um sistema meteorológico de mesoescala na Amazônia Central
No full textThe impact of urbanization on mesoscale meteorological phenomena has been a focus
from various researches. These have shown that urban areas change the spatial pattern
rainfall, and life cycle of the meteorological phenomenon. In the Amazon, large
Cities are typically bordered by rivers and areas of dense forest, which influence and
are influenced by mesoscale convective systems. Studies of how these large
cities, rivers and dense forest, impact the mesoscale phenomena have not yet been
explored. In this work, numerical experiments were performed to evaluate the effect of
the presence of rivers, forests and cities, as well as experiments to assess the impact
of the horizontal growth of the city at the crossing of a squall line(SL). The
results show the convective maximums of the SL are intensified in the passage
about the city. On the other hand, without city, a SL entrance during its passage,
intensifying again after leaving the city. The absence of the river produced a more
early in the city and peaked after through the city. These experimental experiments that are not just the urban effect are responsible intensification of the SL over a city, and that co-dependence with the river influences a distribution and amount of rain. Already with urban expansion there is reduction of cloudiness over a city, which increases the surface pollution balance and changes the patterns of power partitioning. Positive thermal anomaly, imposed by the expansion of the city It is transported to higher levels of the atmosphere and current below the city. This one process, induces or weakens convective activities on the urban surface
leading to reduced accumulation of rain. The combination of impacts caused by
urban sprawl, adds to the diversity of the different types of surface coverage,
in changing local circulations. This change shifts convective activity to far away from the urbanization area in a fast growing city scenario. The effect thermal growth of the urban area also adds to the mechanical effect that leads to formation of an obstruction zone, which makes it difficult to maintain convective systems about the city. In addition, rivers impact or propagation direction of SL after the passage about the city. These results contribute to the understanding of the role of rivers and cities about the development of a SL in the Central Amazon, and shows the refinement of tiles in numerical experiments are fundamental for the representation of interactions between the system and the surface.O impacto da urbanização sobre fenômenos meteorológicos de mesoescala tem sido foco
de diversas pesquisas. Estas têm mostrado que áreas urbanas modificam o padrão espacial
e o volume chuva, e o ciclo de vida do fenômeno meteorológico. Na Amazônia, as grandes
cidades são tipicamente margeadas por rios e áreas de floresta densa, que influenciam e
são influenciadas por sistemas convectivos de mesoescala. Estudos de como estas grandes
cidades, rios e floresta densa, impactam os fenômenos de mesoescala ainda não foram
explorados. Neste trabalho foram realizados experimentos numéricos para avaliar o efeito
da presença de rios, floresta e cidade, como também experimentos para avaliar o impacto
do crescimento horizontal da cidade na passagem de uma linha de instabilidade (LI). Os
resultados mostram que os máximos convectivos da LI são intensificados na passagem
sobre a cidade. Por outro lado, sem a cidade, a LI enfraquece durante sua passagem,
voltando a se intensificar após deixar a cidade. A ausência do rio produziu uma LI mais
fraca, que chegou antecipadamente à cidade e atingiu máximo convectivo após passagem
pela cidade. Estes experimentos mostraram que não apenas o efeito urbano é responsável
pela intensificação da LI sobre a cidade, e que a co-dependência com o rio influencia a
distribuição e quantidade de chuva. Já com a expansão urbana há redução da nebulosidade
sobre a cidade, o que aumenta o saldo de radiação à superfície e modifica os padrões de
particionamento de energia. Anomalia positiva térmica, imposta pela expansão da cidade
é transportada para níveis mais altos da atmosfera e corrente abaixo da cidade. Este
processo, induz o enfraquecimento de atividades convectivas sobre a superfície urbana
levando a redução do acumulado de chuva. A combinação dos impactos provocados pela
expansão urbana, se somam à diversidade dos diferentes tipos de cobertura da superfície,
na mudança das circulações locais. Essa alteração desloca a atividade convectiva para
longe da área de urbanização em um cenário de forte crescimento da cidade. O efeito
térmico do crescimento da área urbana também se soma ao efeito mecânico que conduz a
formação de uma zona de obstrução, que dificulta a manutenção de sistemas convectivos
sobre a cidade. Ademais, os rios impactam o sentido de propagação da LI após passagem
sobre a cidade. Estes resultados contribuem para compreensão do papel de rios e cidades
sobre o desenvolvimento de uma LI na Amazônia Central, e mostra que o refinamento de
escalas nos experimentos numéricos são fundamentais para a representação das interações
entre o sistema e a superfície
Parasitism in Theridion sp. (Araneae: Theridiidae) by Zatypota riverai Gauld, 1991 (Hymenoptera: Ichneumonidae: Pimplinae)
No full textThe hymenopteran genus Zatypota Förster, 1869 (Ichneumonidae: Pimplinae, Ephialtini) comprises highly specialized koinobiont ectoparasitoids of spiders and is the largest genus of the Polysphincta group of genera in the world, with more than 50 described species. The vast majority of species of Zatypota are parasitoids of the spider family Theridiidae. In this study, we present information about a new interaction between the parasitoid spider wasp Zatypota riverai Gauld, 1991 and the host spider Theridion sp. Walckenaer, 1805 (Theridiidae) with information about host weight selection. We collected 102 non-parasitized adult and subadult females of Theridion sp. and six spiders with larvae of Z. riverai attached to host's abdomen. The pupal development takes about 8-11 days, though the development time of the pupa varies with the sex of the wasp. All larvae collected in the field completed their life cycle on the host spiders, even though all of the hosts were small, indicating that the host biomass was sufficient for larval development and no larger-sized spiders are needed. Moreover, larger Theridion probably pose a greater risk because they are more likely to be successful at wasp predation, even if they offer a greater resource to the larva. © 2019 American Museum of Natural History. All rights reserved
Illegal selective logging and forest fires in the northern Brazilian Amazon
Get PDFIllegal selective logging and forest fires occur on a large scale in the northern Brazilian Amazon, contributing to an increase in tree mortality and a reduction in forest carbon stock. A total of 120 plots of 0.25 ha (30 ha) were installed in transitional ecosystems or ecotones (LOt) between the forested shade-loving campinarana (Ld) and dense-canopy rainforest, submontane (Ds), in the National Forest (Flona) of Anauá, southern Roraima. Measuring the diameters at breast height (DBH ≥ 10 cm) and the heights of 171 dead trees (fallen naturally, illegally exploited, and affected by forest fires), enabled the estimation of carbon content from the application of a biomass equation developed at Manaus, and the calculation of a correction factor, using the average height of the largest trees. From 2015-2017, we mapped the real extent of illegal selective logging and forest fires across the region with CLASlite and INPE/Queimadas. From measurements of 14,730 live and dead trees across 30 hectares (491 ± 15 trees·ha -1 ), the illegal selective logging and associated forest fires, and aggravation by severe El Niño droughts resulted in an 8.2% mortality of trees (40 ± 9 dead trees·ha -1 ) and a 3.5% reduction in forest carbon stock (6 ± 3 Mg·ha -1 ) in the short-term. The surface area or influence of forest fires of very high density were estimated in the south-central region of Roraima (8374 km 2 ) and the eastern region of the Flona Anauá (37 km 2 ). Illegal selective logging and forest fires in forest areas totaled 357 km 2 in the mosaic area, and 6 km 2 within Flona Anaua. Illegal selective logging and forest fires in the years of severe El Niño droughts threatened the maintenance of environmental services provided by Amazonian forests. © 2019 by the authors