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tropical forest

Jacqueline Hernández-Martínez, Juan B Morales-Malacara, Mariana Yolotl Alvarez-Añorve, Sergio Amador-Hernández, Ken Oyama, Luis Daniel Avila-Cabadilla
The anthropogenic modification of natural landscapes, and the consequent changes in the environmental conditions and resources availability at multiple spatial scales can affect complex species interactions involving key-stone species such as bat-parasite interactions. In this study, we aimed to identify the drivers potentially influencing host-bat fly interactions at different spatial scales (at the host, vegetation stand and landscape level), in a tropical anthropogenic landscape. For this purpose, we mist-netted phyllostomid and moormopid bats and collected the bat flies (streblids) parasitizing them in 10 sites representing secondary and old growth forest...
May 21, 2018: Parasitology
Yasoja S Athugala, K M G G Jayasuriya, A M T A Gunarathne, Carol C Baskin
Fruiting season of many Sri Lankan tropical montane species is not synchronized and may not occur when conditions are favorable for seedling establishment. We hypothesized that species with different fruiting seasons have different seed dormancy mechanisms to synchronize timing of germination with a favorable season for establishment. Using six species with different fruiting seasons, we tested this hypothesis. Germination and imbibition of intact and manually-scarified seeds were studied. Effect of GA3 on germination was examined...
May 20, 2018: Plant Biology
Jacqueline Heckenhauer, Rosabelle Samuel, Peter S Ashton, Kamariah Abu Salim, Ovidiu Paun
A supra-annual, community-level synchronous flowering prevails in several parts of the tropical forests of Southeast Asia and its evolution has been hypothesized to be linked to pollinator shifts. The aseasonal Southeast Asian lowland rainforests are dominated by Dipterocarpaceae, which exhibit great floral diversity, a range of pollination syndromes and include species with annual and supra-annual gregarious flowering. Phylogenetic relationships within this family are still unclear, especially in the tribe Shoreeae...
May 17, 2018: Molecular Phylogenetics and Evolution
Sreedhar Vijayakrishnan, Mavatur Ananda Kumar, G Umapathy, Vinod Kumar, Anindya Sinha
Increasing anthropogenic pressures on forests, especially in the tropical regions of the world, have restricted several large mammalian species such as the Asian elephant to fragmented habitats within human-dominated landscapes. In this study, we assessed the effects of an anthropogenic landscape and its associated conflict with humans on the physiological stress responses displayed by Asian elephants in the Anamalai Hills of the Western Ghats mountains in south India. We have quantified faecal glucocorticoid metabolite (FGM) concentrations in focal individual elephants within and across herds, inhabiting both anthropogenic and natural habitats, and evaluated their physiological responses to different socio-ecological situations between November 2013 and April 2014...
May 16, 2018: General and Comparative Endocrinology
Lourens Poorter, Carolina V Castilho, Juliana Schietti, Rafael S Oliveira, Flávia R C Costa
The functional trait approach has, as a central tenet, that plant traits are functional and shape individual performance, but this has rarely been tested in the field. Here, we tested the individual-based trait approach in a hyperdiverse Amazonian tropical rainforest and evaluated intraspecific variation in trait values, plant strategies at the individual level, and whether traits are functional and predict individual performance. We evaluated > 1300 tree saplings belonging to > 383 species, measured 25 traits related to growth and defense, and evaluated the effects of environmental conditions, plant size, and traits on stem growth...
May 18, 2018: New Phytologist
J Leighton Reid, Matthew E Fagan, Rakan A Zahawi
Several recent meta-analyses have aimed to determine whether natural regeneration is more effective at recovering tropical forests than active restoration (for example, tree planting). We reviewed this literature and found that comparisons between strategies are biased by positive site selection. Studies of natural forest regeneration are generally conducted at sites where a secondary forest was already present, whereas tree planting studies are done in a broad range of site conditions, including non-forested sites that may not have regenerated in the absence of planting...
May 2018: Science Advances
Brice N Vofo, Gaelle V F Ngankam, Calypse A Ngwasiri, Jeannine A Atem, Leopold N Aminde
BACKGROUND: Endemic Burkitt's lymphoma is found predominantly in malaria holoendemic zones, typically in the tropical rain forest of Africa. It usually presents as an extra-nodal tumour in children and young adults with predilection for jaws and soft tissues of the abdomen. Clinical features depend on the primary tumour site, extent of the disease and histologic subtype. Acute blindness as a presentation sign is rare. CASE PRESENTATION: A 13 year old African female presented to our facility with a 3 week history of painful abdominal distention, and loss of vision of the left eye...
May 16, 2018: Journal of Medical Case Reports
Nobuo Imai, Takuya Furukawa, Riyou Tsujino, Shumpei Kitamura, Takakazu Yumoto
While many tropical countries are experiencing rapid deforestation, some have experienced forest transition (FT) from net deforestation to net reforestation. Numerous studies have identified causative factors of FT, among which forest scarcity has been considered as a prerequisite for FT. In fact, in SE Asia, the Philippines, Thailand and Viet Nam, which experienced FT since 1990, exhibited a lower remaining forest area (30±8%) than the other five countries (68±6%, Cambodia, Indonesia, Laos, Malaysia, and Myanmar) where forest loss continues...
2018: PloS One
Alexandre Antonelli, Alexander Zizka, Fernanda Antunes Carvalho, Ruud Scharn, Christine D Bacon, Daniele Silvestro, Fabien L Condamine
The American tropics (the Neotropics) are the most species-rich realm on Earth, and for centuries, scientists have attempted to understand the origins and evolution of their biodiversity. It is now clear that different regions and taxonomic groups have responded differently to geological and climatic changes. However, we still lack a basic understanding of how Neotropical biodiversity was assembled over evolutionary timescales. Here we infer the timing and origin of the living biota in all major Neotropical regions by performing a cross-taxonomic biogeographic analysis based on 4,450 species from six major clades across the tree of life (angiosperms, birds, ferns, frogs, mammals, and squamates), and integrate >1...
May 14, 2018: Proceedings of the National Academy of Sciences of the United States of America
Ang Wang, Yunting Fang, Dexiang Chen, Oliver Phillips, Keisuke Koba, Weixing Zhu, Jiaojun Zhu
Denitrification is a major process contributing to the removal of nitrogen (N) from ecosystems, but its rate is difficult to quantify. The natural abundance of isotopes can be used to identify the occurrence of denitrification and has recently been used to quantify denitrification rates at the ecosystem level. However, the technique requires an understanding of the isotopic enrichment factor associated with denitrification, which few studies have investigated in forest soils. Here, soils collected from two tropical and two temperate forests in China were incubated under anaerobic or aerobic laboratory conditions for two weeks to determine the N and oxygen (O) isotope enrichment factors during denitrification...
August 15, 2018: Science of the Total Environment
Liubov Volkova, Stephen H Roxburgh, Christopher J Weston, Richard G Benyon, Andrew L Sullivan, Philip J Polglase
Analysis of growth and biomass turnover in natural forests of Eucalyptus regnans, the world's tallest angiosperm, reveals it is also the world's most productive forest type, with fire disturbance an important mediator of net primary productivity (NPP). A comprehensive empirical database was used to calculate the averaged temporal pattern of NPP from regeneration to 250 years age. NPP peaks at 23.1±3.8 (95% inter-quantile range) Mg C ha-1 yr-1 at age 14 years, and declines gradually to about 9.2±0.8 Mg C ha-1 yr-1 at 130 years, with an average NPP over 250 years of 11...
May 14, 2018: Global Change Biology
W G D Chathuranga, S H P P Karunaratne, B R Fernando, W A Priyanka P De Silva
Bird-biting mosquitoes act as bridge vectors of diverse pathogens of emerging infectious diseases. In this study, we report for the first time the abundance, diversity, distribution, and feeding pattern of bird-biting mosquitoes on an island where avifaunal diversity is rich. Monthly mosquito collections were done at six different habitats in three different climatic zones using bird-baited traps over a year. Collected mosquitoes were identified using morphological and molecular tools. A total of 2,655 bird-biting mosquitoes of eight genera and 25 species were identified...
June 2018: Journal of Vector Ecology: Journal of the Society for Vector Ecology
Jian-Guo Huang, Xiali Guo, Sergio Rossi, Lihong Zhai, Biyun Yu, Shaokang Zhang, Mingfang Zhang
China's subtropical forests play a vital role in sequestering global carbon; therefore, it is critical to conduct a precise investigation of intra-annual wood formation in these ecosystems to clarify the mechanisms behind this. Two field experiments were established in Chinese subtropical forests to monitor weekly the intra-annual xylem formation of Pinus massoniana Lamb. from January to December 2015, using the recently developed micro-sampling approach. The effects of climate on wood formation were also assessed using linear or mixed models...
May 11, 2018: Tree Physiology
Kwabena Asubonteng, Karin Pfeffer, Mirjam Ros-Tonen, Jan Verbesselt, Isa Baud
Tree crops such as cocoa and oil palm are important to smallholders' livelihoods and national economies of tropical producer countries. Governments seek to expand tree-crop acreages and improve yields. Existing literature has analyzed socioeconomic and environmental effects of tree-crop expansion, but its spatial effects on the landscape are yet to be explored. This study aims to assess the effects of tree-crop farming on the composition and the extent of land-cover transitions in a mixed cocoa/oil palm landscape in Ghana...
May 11, 2018: Environmental Management
Vitor Carneiro de Magalhães Tolentino, Camilla Queiroz Baesse, Celine de Melo
The structure and organization of acoustic signals arise through evolutionary processes and adaptive pressures on each species. During learning, natural or anthropogenic factors, such as high noise levels in urban areas, pose challenges to acoustic communication in birds. Many species adjust their acoustic signals to higher noise levels by increasing the frequency of vocalizations. The objectives of this study were to compare the dominant frequency of songs among birds dwelling in forest fragments distant from and near to urban areas, establish correlations between the dominant frequency of song and noise levels in these environments and verified the difference of response between oscines, suboscines and non-passerines...
April 2018: Environmental Pollution
Daniel B Metcalfe, Wanderley Rocha, Jennifer K Balch, Paulo M Brando, Christopher E Doughty, Yadvinder Malhi
Fire at the dry southern margin of the Amazon rainforest could have major consequences for regional soil carbon (C) storage and ecosystem carbon dioxide (CO2 ) emissions, but relatively little information exists about impacts of fire on soil C cycling within this sensitive ecotone. We measured CO2 effluxes from different soil components (ground surface litter, roots, mycorrhizae, soil organic matter) at a large-scale burn experiment designed to simulate a severe but realistic potential future scenario for the region (Fire plot) in Mato Grosso, Brazil, over one year, and compared these measurements to replicated data from a nearby, unmodified Control plot...
May 10, 2018: Global Change Biology
Chu Peng, He Wang, Yingying Jiang, Jinhua Yang, Hangxian Lai, Xiaomin Wei
Thus far, no studies have investigated the soil microbial diversity over an elevational gradient in Taibai Mountain, the central massif of the Qinling Mountain Range. Here, we used Illumina sequencing and quantitative PCR of the 16S rRNA gene to assess the diversity and abundance of bacterial communities along an elevational gradient in representative vegetation soils in Taibai Mountain. We identified the soil, climate, and vegetation factors driving the variations in soil bacterial community structure by Pearson correlation and redundancy analysis...
May 10, 2018: Microbial Ecology
Ceri Shipton, Patrick Roberts, Will Archer, Simon J Armitage, Caesar Bita, James Blinkhorn, Colin Courtney-Mustaphi, Alison Crowther, Richard Curtis, Francesco d' Errico, Katerina Douka, Patrick Faulkner, Huw S Groucutt, Richard Helm, Andy I R Herries, Severinus Jembe, Nikos Kourampas, Julia Lee-Thorp, Rob Marchant, Julio Mercader, Africa Pitarch Marti, Mary E Prendergast, Ben Rowson, Amini Tengeza, Ruth Tibesasa, Tom S White, Michael D Petraglia, Nicole Boivin
The Middle to Later Stone Age transition in Africa has been debated as a significant shift in human technological, cultural, and cognitive evolution. However, the majority of research on this transition is currently focused on southern Africa due to a lack of long-term, stratified sites across much of the African continent. Here, we report a 78,000-year-long archeological record from Panga ya Saidi, a cave in the humid coastal forest of Kenya. Following a shift in toolkits ~67,000 years ago, novel symbolic and technological behaviors assemble in a non-unilinear manner...
May 9, 2018: Nature Communications
Bradley K Woodworth, D Ryan Norris, Brendan A Graham, Zachary A Kahn, Daniel J Mennill
Understanding how climate change will shape species distributions in the future requires a functional understanding of the demographic responses of animals to their environment. For birds, most of our knowledge of how climate influences population vital rates stems from research in temperate environments, even though most of Earth's avian diversity is concentrated in the tropics. We evaluated effects of Southern Oscillation Index (SOI) and local temperature and rainfall at multiple temporal scales on sex-specific survival of a resident tropical bird, the rufous-and-white wren Thryophilus rufalbus , studied over 15 years in the dry forests of northwestern Costa Rica...
May 16, 2018: Proceedings. Biological Sciences
Travis S Steffens, Shawn M Lehman
Determining what factors affect species occurrence is vital to the study of primate biogeography. We investigated the metapopulation dynamics of a lemur community consisting of eight species (Avahi occidentalis, Propithecus coquereli, Microcebus murinus, Microcebus ravelobensis, Lepilemur edwardsi, Cheirogaleus medius, Eulemur mongoz, and Eulemur fulvus) within fragmented tropical dry deciduous forest habitat in Ankarafantsika National Park, Madagascar. We measured fragment size and isolation of 42 fragments of forest ranging in size from 0...
2018: PloS One
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