Diversity and Altitudinal Distribution of Understorey Corticolous Lichens in a Tropical Montane Forest in Kenya (East Africa)

Lichens constitute an important component of tropical forest biodiversity. This study inventoried corticolous lichens and examined their variation in various forest types with varying climatic conditions in Mt. Kenya, East Africa. Specifically we evaluated variation of lichen assemblages in relation to forest types and tree diversity along an altitudinal gradient (1800-3100m). Ten study sites were established on two contrasting sides of Mt. Kenya in the indigenous forest: six of them at Chogoria which is on the humid southeastern windward side of the mountain and four sites on the Sirimon side located on the drier northwestern leeward side. Overall 242 lichen taxa were documented; with Chogoria and Sirimon forests having 148 and 94 species that translated to an adequate sampling effort of 74 % and 68 %, respectively. The two contrasting forest types (Chogoria and Sirimon) supported slightly different lichens assemblages. Meanwhile lichen assemblages were found to significantly vary with elevation (or forest types) and with tree host. Posterior analyses showed that the differences were significant among sampling sites (or forest types) on the Chogoria side and insignificant on the Sirimon side. Similarly the number of lichens differed significantly among the host tree species. This study stresses the urgent need to upscale the sustainable management of the presently threatened tropical forests in order to preserve their structural heterogeneity.

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Effect of patches of woody vegetation on the role of fire in tropical grasslands and savannas

International Journal of Wildland Fire ◽

10.1071/wf13119 ◽

2014 ◽

Vol 23 (3) ◽

pp. 410 ◽

Cited By ~ 3

Author(s):

Frank van Langevelde ◽

Casper de Groot ◽

Thomas A. Groen ◽

Ignas M. A. Heitkönig ◽

Ian Gaigher

Keyword(s):

Patch Size ◽

Fire Effects ◽

Climatic Conditions ◽

Windward Side ◽

Woody Vegetation ◽

Leeward Side ◽

Tree Seedlings ◽

Tropical Grasslands ◽

Vegetation Expansion

In tropical grasslands and savannas, fire is used to reduce woody vegetation expansion. Woody vegetation in these biomes is often patchily distributed, and micro-climatic conditions can largely vary locally with unknown consequences for fire effects. We hypothesised that (1) fire has higher temperature and maintains high temperatures for a longer period at the windward side than at the leeward side of wooded patches, (2) this difference increases with patch size, (3) fire has a larger effect on woody vegetation at the windward side than at the leeward side of wooded patches and (4) this effect increases with patch size. We planted tree seedlings around wooded patches in a grassland and burnt these plots. We found that fire had a lower temperature and had an elevated temperature for a shorter time period at the leeward side of wooded patches than at the windward side. Also, we found smaller effect of fire on the seedlings at the leeward side. We conclude that patches of woody vegetation can have a large effect on the role of fire in tropical grasslands and savannas. This effect suggests a ‘safe zone’ for seedlings at the leeward side, which consequently promotes woody vegetation expansion. This paper contributes to understanding of the effect of patchiness of woody vegetation on the role of fire in tropical grasslands and savannas in reducing woody vegetation expansion.

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Investigation on the drag effect of a rolling element confined in the cavity of a cylindrical roller bearing

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/13506501211026063 ◽

2021 ◽

pp. 135065012110260

Author(s):

Wenjun Gao ◽

Shuo Zhang ◽

Xiaohang Li ◽

Zhenxia Liu

Keyword(s):

Open Space ◽

Roller Bearing ◽

Flow Characteristics ◽

Experimental Tests ◽

Windward Side ◽

Leeward Side ◽

Drag Effect ◽

Rolling Element ◽

Cylindrical Roller Bearing ◽

Cylindrical Roller

In cylindrical roller bearings, the drag effect may be induced by the rolling element translating in a fluid environment of the bearing cavity. In this article, the computational fluid dynamics method and experimental tests are employed to analyse its flow characteristics and pressure distribution. The results indicate that the pressure difference between the windward side and the leeward side of the cylinder is raised in view of it blocking the flow field. Four whirl vortexes are formed in four outlets of two wedge-shaped areas between the front part of the cylindrical surface and adjacent walls for the cylinder of L/ D = 1.5 at Re = 4.5 × 103. Vortex shedding is found in the direction of cylinder axis at Re = 4.5 × 104. The relationship between drag coefficient and Reynolds number is illustrated, obviously higher than that of the two-dimensional cylinder in open space.

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A comparative UHPLC-Q/TOF–MS-based eco-metabolomics approach reveals temperature adaptation of four Nepenthes species

Scientific Reports ◽

10.1038/s41598-020-78873-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Changi Wong ◽

Yee Soon Ling ◽

Julia Lih Suan Wee ◽

Aazani Mujahid ◽

Moritz Müller

Keyword(s):

Heat Stress ◽

Metabolic Response ◽

Natural Habitat ◽

Climatic Conditions ◽

Temperature Adaptation ◽

Altitudinal Distribution ◽

Distinct Temperature ◽

Survival Mechanisms ◽

Metabolite Regulation ◽

Tof Ms

AbstractNepenthes, as the largest family of carnivorous plants, is found with an extensive geographical distribution throughout the Malay Archipelago, specifically in Borneo, Philippines, and Sumatra. Highland species are able to tolerate cold stress and lowland species heat stress. Our current understanding on the adaptation or survival mechanisms acquired by the different Nepenthes species to their climatic conditions at the phytochemical level is, however, limited. In this study, we applied an eco-metabolomics approach to identify temperature stressed individual metabolic fingerprints of four Nepenthes species: the lowlanders N. ampullaria, N. rafflesiana and N. northiana, and the highlander N. minima. We hypothesized that distinct metabolite regulation patterns exist between the Nepenthes species due to their adaptation towards different geographical and altitudinal distribution. Our results revealed not only distinct temperature stress induced metabolite fingerprints for each Nepenthes species, but also shared metabolic response and adaptation strategies. The interspecific responses and adaptation of N. rafflesiana and N. northiana likely reflected their natural habitat niches. Moreover, our study also indicates the potential of lowlanders, especially N. ampullaria and N. rafflesiana, to produce metabolites needed to deal with increased temperatures, offering hope for the plant genus and future adaption in times of changing climate.

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2.5D Flexible Wind Sensor Using Differential Plate Capacitors

Sensors ◽

10.3390/s21093101 ◽

2021 ◽

Vol 21 (9) ◽

pp. 3101

Author(s):

Yu Wan ◽

Zhenxiang Yi

Keyword(s):

Wind Speed ◽

Wind Direction ◽

Parallel Plate ◽

Electrode Array ◽

Copper Electrode ◽

Windward Side ◽

Leeward Side ◽

Electrode Layer ◽

Young’S Moduli ◽

Speed Up

In this paper, a novel 2.5-dimensional (2.5D) flexible wind sensor is proposed based on four differential plate capacitors. This design consists of a windward pillar, two electrode layers, and a support layer, which are all made of polydimethylsiloxane (PDMS) with different Young’s moduli. A 2 mm × 2 mm copper electrode array is located on each electrode layer, forming four parallel plate capacitors as the sensitive elements. The wind in the xy-plane tilts the windward pillar, decreasing two capacitances on the windward side and increasing two capacitances on the leeward side. The wind in the z-axis depresses the windward pillar, resulting in an increase of all four capacitances. Experiments demonstrate that this sensor can measure the wind speed up to 23.9 m/s and the wind direction over the full 360° range of the xy-plane. The sensitivities of wind speed are close to 4 fF·m−1·s and 3 fF·m−1·s in the xy-plane and z-axis, respectively.

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Are seed mass and seedling size and shape related to altitude? Evidence in Gymnocalycium monvillei (Cactaceae)

Botany ◽

10.1139/cjb-2015-0026 ◽

2015 ◽

Vol 93 (8) ◽

pp. 529-533 ◽

Cited By ~ 8

Author(s):

Karen Bauk ◽

Reyes Pérez-Sánchez ◽

Sebastián R. Zeballos ◽

M. Laura Las Peñas ◽

Joel Flores ◽

...

Keyword(s):

Negative Relationship ◽

Seed Mass ◽

Climatic Conditions ◽

Mean Annual Temperature ◽

Altitudinal Distribution ◽

Seedling Morphology ◽

Seedling Size ◽

Size And Shape ◽

Seedling Traits ◽

Species Response

Several studies reported a negative relationship between altitude and seed mass. In cactus species, seed mass has been also related to seedling morphology (size and shape). Here we studied Gymnocalycium monvillei (Lem.) Pfeiff. ex Britton & Rose, a cactus species with a wide altitudinal distribution, with the main aim of analyzing how altitude affects seed mass and seedling size (height and width) and shape (globose or columnar). We collected seeds from five sites along the entire altitudinal distribution of the species in the Córdoba Mountains (sites were located between 878 and 2230 m a.s.l.), encompassing a marked climatic gradient (6 °C of mean annual temperature difference between the extreme sites). Seed mass and seedling traits were measured in the laboratory. Seedling height increased with altitude, whereas seed mass was not related to this parameter. Seedlings became more globose (reduced surface/volume ratio) with decreasing altitude. Variation in seedling shape along the altitudinal gradient may be related to the contrasting climatic conditions to which seedlings are exposed, and could account for the wide altitudinal distribution of G. monvillei. Our results highlight the importance of seedling traits in the species’ response to climatic change.

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Air movement and heat loss from sheep. II. Thermal insulation of fleece in wind

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1980.0091 ◽

1980 ◽

Vol 209 (1175) ◽

pp. 209-217 ◽

Cited By ~ 16

Keyword(s):

Thermal Diffusivity ◽

Heat Loss ◽

Thermal Insulation ◽

General Relation ◽

Windward Side ◽

Leeward Side ◽

Sensible Heat ◽

Bulk Resistance ◽

Air Movement ◽

Dimensionless Constant

Penetration of an animal’s coat by wind reduces its thermal insulation and increases heat loss to the environment. From studies of the sensible heat loss from a life-sized model sheep covered with fleece, the average fleece resistance r¯ f (s cm -1 ) was related to windspeed u (m s -1 ) by 1/ r¯ f ( u ) = l/ r¯ f (0) + cu , where c is a dimensionless constant. As c is expected to be inversely proportional to coat depth Î , the more general relation k¯ ( u ) = k¯ (0) + c'u was evaluated, where k¯ = Î / r¯ f is the thermal diffusivity (cm 2 s -1 ) of the fleece and c' = cÎ is another constant (cm). The orientation of the model to the wind had little effect on the bulk resistance of the fleece, but the resistance on the windward side was substantially lower than on the leeward side.

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Phyllostomidae assemblage (Chiroptera: Mammalia) in altitudinal forests at the Parque Estadual do Ibitipoca, Southeast of Minas Gerais, Brazil

Iheringia Série Zoologia ◽

10.1590/1678-4766e2016021 ◽

2016 ◽

Vol 106 (0) ◽

Author(s):

Rodrigo M. Mello ◽

Pedro H. Nobre ◽

Marco A. Manhães ◽

Alexmar S. Rodrigues

Keyword(s):

Species Composition ◽

Floristic Composition ◽

Abundant Species ◽

Minas Gerais ◽

Forest Types ◽

Mountainous Areas ◽

Ecological Relevance ◽

Forest Region ◽

Study Sites ◽

Artibeus Lituratus

ABSTRACT Many studies have demonstrated the ecological relevance and great biodiversity of bats in Brazil. However, mountainous areas have been disproportionately less sampled, mainly in the Southeast. The aim of this study was to identify and compare the richness and diversity of Phyllostomidae, the most diverse bat family, in different forest types in Parque Estadual do Ibitipoca, trying to understand the causes of possible differences. The Parque Estadual do Ibitipoca is inserted in the Serra da Mantiqueira's domain, in an Atlantic Forest region known as "Zona da Mata", state of Minas Gerais, with an altitudinal range between 1200-1784 meters. The study was conducted in two forest types, classified as "Nanofloresta Nebular" and "Floresta Nebular", whose respective data on richness and diversity were compared. The bats were captured with 8-10 mist nets for 14 months (April 2011 to May 2012) and four nights per month totaling 62,171.25 m2h of capture effort. A total of 392 captures (12 species) belonging to the Phyllostomidae family were obtained. The most abundant species were Sturnira lilium (59.9%), Platyrrhinus lineatus (11.3%), Artibeus lituratus (8.7%) and Carollia perspicillata (7.6%). The two sampled areas presented differences in bat richness, diversity and species composition, and this difference was predominantly influenced by S. lilium. It is likely that the observed difference in the assembly of bats between the two study sites depends on the variation in floristic composition. The records of A. lituratus and P. lineatus in a few months of the year and close to Ficus mexiae bearing ripe fruits suggests that at least these species move to the park for a few periods of the year in search of food resources, possibly moving through the altitudinal landscapes.

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Dust-related impacts of mining operations on rangeland vegetation and soil: a case study in Yazd province, Iran

10.21203/rs.3.rs-245412/v1 ◽

2021 ◽

Author(s):

Shahab IbrahimPour ◽

Alireza KhavaninZadeh ◽

Ruhollah Taghizadeh mehrjardi ◽

Hans De Boeck ◽

Alvina Gul

Keyword(s):

Seed Germination ◽

Vegetation Cover ◽

Microbial Respiration ◽

Germination Rate ◽

Windward Side ◽

Leeward Side ◽

Mining Operations ◽

Soil Microbial ◽

Soil Microbial Respiration ◽

The Impact

Abstract Destructive mining operations are affecting large areas of natural ecosystems, especially in arid lands. The present study aims at investigating the impact of iron mine exploitation on vegetation and soil in Nodoushan (Yazd province, central Iran). Based on the dominant wind, topography, slope, vegetation and soil of the area, soil and vegetation parameters close to the mine were recorded and analyzed according to the distance from the mine. In order to obtain the vegetation cover, a transect and plot on the windward and leeward side of the mine, with 100 m intervals and three replicates at each sampling location was used, yielding 96 soil samples. The amount of dust on the vegetation, the seed weight and seed germination rate of Artemisia sp. as the dominant species within the area, and the soil microbial respiration were measured. The relationship between vegetation cover and distance from the mine was not linear, which was due to an interplay between pollution from the mine and local grazing, while other factors did increase or decrease linearly. The results showed that, as the distance from the mine increased, the weight of 1000 seeds of Artemisia sp. was significantly increased from 271 to 494 mg and seed germination rate and soil microbial respiration were significantly increased from 11.7 to 48.4 % and from 4.5 to 5.9 mg CO2 g− 1 soil day− 1 respectively, while the amount of dust significantly decreased from 43.5 to 6 mg (g plant)−1 between the distance of 100 to 600 m from the mine in the leeward direction. A similar trend was observed in the windward side, though negative effects were lower compared to the same distance along the leeward sample locations. The direct and indirect effects on plant growth and health from mining impacts generally decreased linearly with increasing distance from the mine, up to at least 600 m. Our study serves as a showcase for the potential of bio-indicators as a cost-effective method for assessing impacts of mining activities on the surrounding environment.

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A description of the physical properties of selected sediments of the Weichselian and Wartanian glaciations

Bulletin of Geography Physical Geography Series ◽

10.1515/bgeo-2016-0009 ◽

2016 ◽

Vol 10 (1) ◽

pp. 123-132

Author(s):

Ewa Labak-Mechowska

Keyword(s):

Physical Properties ◽

Relative Density ◽

Climatic Conditions ◽

Plasticity Index ◽

Geotechnical Parameters ◽

Constrained Modulus ◽

North Eastern ◽

Subsurface Sediments ◽

Engineering Parameters ◽

Study Sites

Abstract Subsurface sediments in Poland were deposited mainly in the Pleistocene, and have varying origins and, consequently, differing geological and engineering parameters. Fluvioglacial deposits were formed during both the glacial and interglacial periods, which differed from each other in climatic conditions. Based on the results of laboratory analysis and fieldwork, till and fluvioglacial sands were compared in Central and North-Eastern Poland. The research included consistency limits, relative density, plasticity index, constrained modulus of initial compressibility and modulus of initial deformation. Despite the existing view that there exists a large diversity of geological, engineering and geotechnical parameters of variously-aged deposits in Poland, no major differences in their properties were determined at the study sites.

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Recover and They’ll Come: Flower Visiting Bees Benefit from the Continuous of Micro-Environments Set by Regenerating Forest Fragments

Sociobiology ◽

10.13102/sociobiology.v68i1.5861 ◽

2021 ◽

Vol 68 (1) ◽

pp. 5861

Author(s):

Ana Isabel Sobreiro ◽

Lucas Lopes da Silveira Peres ◽

Jessica Amaral Henrique ◽

Rosilda Mara Mussury ◽

Valter Vieira Alves-Junior

Keyword(s):

Urban Areas ◽

Environmental Changes ◽

Climatic Conditions ◽

Agricultural Activity ◽

Forest Fragments ◽

Forest Types ◽

Continuous Forest ◽

Flower Visiting ◽

Bee Communities ◽

Forest Habitats

Forest habitats are important sources of food and nesting resources for pollinators, primarily in urban areas and landscapes with intense agricultural activity. The forest fragmentation and environmental changes occurring in these green refuges are known to impose survival challenges to pollinating bees, leading to species loss. However, it is not well known how the species of bees that visit flowers are distributed in forest micro-environments. To fill this gap, we sampled flower visiting bees in a continuous forest matrix with micro-environments of two forest types (mature and regenerating forest). We examined how the local environmental changes and climatic conditions affect the composition and uniformity of bee communities in the different micro-environments. Our results indicated that both abundance and richness were similar between forest types studied here, however climatic conditions and plant flowering patterns affect the composition of bees. Thus, our results demonstrated that the continuous micro-environments can favor floral visits and the reintegration of bee communities, and still, that this strategy can be used to minimize the impacts of environmental changes at local scales.

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