scholarly journals Pathogenic Variability of Pyricularia grisea from the High- and Mid-Elevation Zones of Bhutan

2000 ◽  
Vol 90 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Thinlay ◽  
R. S. Zeigler ◽  
M. R. Finckh
Keyword(s):  
Rice Cultivar ◽  
High Elevation ◽  
Individual Plant ◽  
Growing Seasons ◽  
Reaction Index ◽  
Agroecological Zones ◽  
Pathogenic Variability ◽  
Almost All ◽  
High Elevations ◽  
Virulence Spectrum

Thirty isolates of P. griseacollected from rice during a blast epidemic in 1995 in the high (1,800 to 2,600 m) and middle (1,200 to 1,800 m) elevations of Bhutan and 80 isolates collected from one rice cultivar from two high- and two mid-elevation sites in 1996 were analyzed for virulence. Differential varieties were indica CO39, with five near-isogenic lines (NILs) for resistance genes in the genetic background of CO39, and japonica Lijiangxintuanheigu (LTH), with five NILs for LTH. Twelve selected Bhutanese landraces also were studied. In addition, 10 blast nurseries consisting of the NIL sets, important local landraces, and representatives of international differential groups were established in the 1996 and 1997 growing seasons in the mid- and high-elevation agroecological zones. The 110 isolates were differentiated into 53 pathotypes based on the 2 NIL sets. Thirteen isolates were avirulent on all of the NILs but were compatible with some landraces. Several isolates were able to attack one of the NILs of CO39 but not CO39. These results strongly suggest that both CO39 and LTH possess previously unidentified resistance. The landraces were not uniform in their reactions to the isolates. When a reaction index taking into account all individual plant reactions was used, isolates that had been assigned to the same pathotype could be further differentiated, indicating that the NIL sets could not completely discriminate virulences in Bhutanese P. grisea populations. In the trap nurseries, disease was always present in the middle elevations, but disease was very low during July 1996 in the high elevations and only present during August and September 1997. Almost all varietal groups were more frequently attacked in the middle than in the high elevations, indicating that the virulence spectrum is wider and the conduciveness of the environment is greater in the middle elevations. Landraces from the high elevations were most susceptible, followed by international differential groups 7 and 8. The results suggest that selection has yielded landraces with more complete and complex resistance in the more disease-conducive mid-elevation environment. At the same time, the pathogen population also possesses a wider virulence spectrum in that environment.

scholarly journals Does Hyperoxia Restrict Pyrenean Rock Lizards Iberolacerta bonnali to High Elevations?

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 200
Author(s):  
Eric J. Gangloff ◽  
Sierra Spears ◽  
Laura Kouyoumdjian ◽  
Ciara Pettit ◽  
Fabien Aubret
Keyword(s):  
High Elevation ◽  
Conservation Strategy ◽  
The Novel ◽  
Thermal Physiology ◽  
Treatment Groups ◽  
Thermal Performance Curve ◽  
And Performance ◽  
Thermal Preferences ◽  
High Elevations ◽  
Intense Radiation

Ectothermic animals living at high elevation often face interacting challenges, including temperature extremes, intense radiation, and hypoxia. While high-elevation specialists have developed strategies to withstand these constraints, the factors preventing downslope migration are not always well understood. As mean temperatures continue to rise and climate patterns become more extreme, such translocation may be a viable conservation strategy for some populations or species, yet the effects of novel conditions, such as relative hyperoxia, have not been well characterised. Our study examines the effect of downslope translocation on ectothermic thermal physiology and performance in Pyrenean rock lizards (Iberolacerta bonnali) from high elevation (2254 m above sea level). Specifically, we tested whether models of organismal performance developed from low-elevation species facing oxygen restriction (e.g., hierarchical mechanisms of thermal limitation hypothesis) can be applied to the opposite scenario, when high-elevation organisms face hyperoxia. Lizards were split into two treatment groups: one group was maintained at a high elevation (2877 m ASL) and the other group was transplanted to low elevation (432 m ASL). In support of hyperoxia representing a constraint, we found that lizards transplanted to the novel oxygen environment of low elevation exhibited decreased thermal preferences and that the thermal performance curve for sprint speed shifted, resulting in lower performance at high body temperatures. While the effects of hypoxia on thermal physiology are well-explored, few studies have examined the effects of hyperoxia in an ecological context. Our study suggests that high-elevation specialists may be hindered in such novel oxygen environments and thus constrained in their capacity for downslope migration.

scholarly journals HSE Management System for Hotwork Operation at High Elevation in Shipbuilding Project

2018 ◽  
Vol 203 ◽  
pp. 02005 ◽  
Author(s):  
Idris Othman ◽  
Mohd Fauzan Helmy Ibrahim ◽  
Nasir Shafiq ◽  
Hisham Mohamad ◽  
Md Salim Kamil
Keyword(s):  
Management System ◽  
Safety Management ◽  
High Elevation ◽  
Peninsular Malaysia ◽  
Survey Method ◽  
Liquefied Petroleum Gas ◽  
The People ◽  
Fall From Height ◽  
Class C ◽  
Almost All

Shipyard industry is one of the growing industry in Malaysia. There is still a lot of room for improvement with regards to the safety aspects within the industry. This study presents the finding of a survey on the safety management in shipyard operation of class C and D in Peninsular Malaysia registered with Ministry of Finance Malaysia. Shipyard operation is considered a hazardous job. Most of the cases were due to fall from height, fire and explosion. Similar accidents happened in South Korea, where 8 fatalities and 31 injuries were reported in January to August 2017. The accidents were due to crane collapsed and explosion during welding works inside a hull of a Liquefied Petroleum Gas (LPG) carrier. This paper aims to study the Health, Safety and Environment Management System (HSEMS) of shipyard operations in Malaysia particularly in Class C and Class D shipyard. This study was conducted using a survey method following the Glenn D’s equation. The survey was targeted at the people who are involved in the industry including the staffs of clients, consultants and contractors. The findings of this study show that almost all the shipyards of Class C and D have HSEMS in placed but some are incomplete. Accidents still happen in the Malaysian shipyard industry from time to time. The gaps in the HSEMS that lead to the accident are highlighted in this paper. Nearly 10% of Class C and D shipyards do not have clear HSE Policy and this one of possible causes of accidents due to low priority given to HSE matters in this particular Class C and D shipyard.

scholarly journals Performance of twelve mango cultivars grown in different agroecological zones of Bangladesh

2013 ◽  
Vol 37 (4) ◽  
pp. 691-710 ◽  
Author(s):  
K Kobra ◽  
MA Hossain ◽  
MAH Talukder ◽  
MAJ Bhuyan
Keyword(s):  
Plant Growth ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Soluble Solids Content ◽  
Flower Production ◽  
Pests And Diseases ◽  
Agroecological Zones ◽  
Solids Content ◽  
Almost All ◽  
Perfect Flower

Twelve commercial and promising mango cultivars were evaluated at three agroecological zones of Bangladesh viz., Akbarpur (AEZ 29), Chapai Nawabgonj (AEZ 11), and Gazipur (AEZ 28) during 2006-07 to investigate their regional adaptability. Cultivars included in the experiment were Ashwina, BARI Aam-1, Bombai, Deori, Fazli, Gopalbhog, Kalia, Khirsapat, Langra, Lata Bombai, Rani Passand, and Surjapuri. The plants were transplanted in the field during July 1993. Tree volume was the maximum (79.78 m3) in Khirsapat and the minimum in Lata Bombai (21.92 m3). Langra had the highest percentage of perfect flower (27%), while the lowest was in Deori and Kalia (5%). The earliest and latest fruit was harvested from BARI Aam-1 and Ashwina, respectively, at all locations. All the cultivars were harvested 3-5 and 8-10 days earlier at Akbarpur and Gazipur, respectively, compared to that at Chapai Nawabgonj. The highest individual fruit weight was obtained from Fazli at all locations, while Gopalbhog (130 g) had the lowest fruit weight at Akbarpur and Surjapuri at Chapai Nawabgonj (172 g) and Gazipur (140 g). Total soluble solids content was reasonably high in all the cultivars at each location (around 20%) except Ashwina, Lata Bombai, and Surjapuri which contained around 16% TSS. Lata Bombai was highly susceptible to anthracnose, floral malformation, and stem-end-rot at almost all the locations. Other cultivars showed low to medium susceptibility to all these diseases. The highest and lowest fruit producing cultivars were Khirsapat (206) and Lata Bombai (106) at Gazipur, while Rani Passand (196) and Bombai, Lata Bombai (92) at Akbarpur but at Chapai Nawabgonj, these were Langra (325) and Deori (117), respectively. Cultivar Fazli (83.61 kg) was the highest yielder by weight, while Lata Bombai (18.35 kg) was the lowest. Among the locations, Chapai Nawabgonj was the most favourable for plant growth, perfect flower production, and yield, and least favourable for pests and diseases. The overall result of the experiment indicated that good quality mango could also be grown successfully under Akbarpur and Gazipur conditions adopting appropriate variety like Khirsapat. DOI: http://dx.doi.org/10.3329/bjar.v37i4.14394 Bangladesh J. Agril. Res. 37(4): 691-710, December 2012

scholarly journals High turn-over rates at the upper range limit and elevational source-sink dynamics in a widespread songbird

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin U. Grüebler ◽  
Johann von Hirschheydt ◽  
Fränzi Korner-Nievergelt
Keyword(s):  
Environmental Gradients ◽  
Elevational Gradient ◽  
High Elevation ◽  
Range Limit ◽  
Apparent Survival ◽  
Breeding Sites ◽  
Mobile Species ◽  
Source Sink ◽  
Turn Over ◽  
High Elevations

AbstractThe formation of an upper distributional range limit for species breeding along mountain slopes is often based on environmental gradients resulting in changing demographic rates towards high elevations. However, we still lack an empirical understanding of how the interplay of demographic parameters forms the upper range limit in highly mobile species. Here, we study apparent survival and within-study area dispersal over a 700 m elevational gradient in barn swallows (Hirundo rustica) by using 15 years of capture-mark-recapture data. Annual apparent survival of adult breeding birds decreased while breeding dispersal probability of adult females, but not males increased towards the upper range limit. Individuals at high elevations dispersed to farms situated at elevations lower than would be expected by random dispersal. These results suggest higher turn-over rates of breeding individuals at high elevations, an elevational increase in immigration and thus, within-population source-sink dynamics between low and high elevations. The formation of the upper range limit therefore is based on preference for low-elevation breeding sites and immigration to high elevations. Thus, shifts of the upper range limit are not only affected by changes in the quality of high-elevation habitats but also by factors affecting the number of immigrants produced at low elevations.

scholarly journals Dynamical analysis of the global elevational diversity gradient in passerine birds reveals a prominent role for highlands as species pumps

2020 ◽  
Author(s):  
Paul van Els ◽  
Leonel Herrera-Alsina ◽  
Alex L. Pigot ◽  
Rampal Etienne
Keyword(s):  
Evolutionary Dynamics ◽  
Strong Support ◽  
High Elevation ◽  
Dynamical Analysis ◽  
Reverse Direction ◽  
Passerine Birds ◽  
Diversification Rates ◽  
Diversity Gradient ◽  
As Species ◽  
Almost All

Abstract Low elevation regions harbor the majority of the world’s species diversity compared to high elevation areas. This global elevational diversity gradient, suggests that lowland species have had more time to diversify, or that net diversification rates have been higher in the lowlands (either due to higher ecological limits or intrinsically higher diversification rates). However, highlands seem to be cradles of diversity as they contain many young endemics, suggesting that their rates of speciation are exceptionally fast. Here, we use a phylogenetic diversification model that accounts for the dispersal of species between different elevations to examine the evolutionary dynamics of the elevational diversity gradient in passerine birds, a group that has radiated globally to occupy almost all elevations and latitudes. We find strong support for a model where passerines diversify at the same rate in the highlands and the lowlands but where the rate of dispersal from high to low elevations is more than twice as fast as in the reverse direction. This suggests that while there is no consistent trend in diversification across elevations, highland regions act as species pumps because the diversity they generate migrates into the lowlands, thus setting up the observed gradient in passerine diversity. This species pump is particularly strong in the tropics, where the inferred rate of speciation is 1.4 times faster than in the temperate zone. We conclude that despite their lower diversity, highland regions are disproportionally important for maintaining diversity in the adjacent lowlands. The extinction of species in the tropical highlands due to rapid climate change this century could thus have major and long-lasting impacts on global passerine diversity.

scholarly journals Air temperature variability in a high-elevation Himalayan catchment

2016 ◽  
Vol 57 (71) ◽  
pp. 212-222 ◽  
Author(s):  
Martin Heynen ◽  
Evan Miles ◽  
Silvan Ragettli ◽  
Pascal Buri ◽  
Walter W. Immerzeel ◽  
...  
Keyword(s):  
Air Temperature ◽  
Land Surface ◽  
Monsoon Season ◽  
High Elevation ◽  
Catchment Scale ◽  
Diurnal Variability ◽  
Atmosphere Interaction ◽  
Temperature Seasonality ◽  
Lapse Rates ◽  
High Elevations

AbstractAir temperature is a key control of processes affecting snow and glaciers in high-elevation catchments, including melt, snowfall and sublimation. It is therefore a key input variable to models of land–surface–atmosphere interaction. Despite this importance, its spatial variability is poorly understood and simple assumptions are made to extrapolate it from point observations to the catchment scale. We use a dataset of 2.75 years of air temperature measurements (from May 2012 to November 2014) at a network of up to 27 locations in the Langtang River, Nepal, catchment to investigate air temperature seasonality and consistency between years. We use observations from high elevations and from the easternmost section of the basin to corroborate previous findings of shallow lapse rates. Seasonal variability is strong, with shallowest lapse rates during the monsoon season. Diurnal variability is also strong and should be taken into account since processes such as melt have a pronounced diurnal variability. Use of seasonal lapse rates seems crucial for glacio-hydrological modelling, but seasonal lapse rates seem stable over the 2–3 years investigated. Lateral variability at transects across valley is high and dominated by aspect, with south-facing sites being warmer than north-facing sites and deviations from the fitted lapse rates of up to several degrees. Local factors (e.g. topographic shading) can reduce or enhance this effect. The interplay of radiation, aspect and elevation should be further investigated with high-elevation transects.

Alteration in plant spacing improves submergence tolerance in Sub1 and non-Sub1 rice (cv. IR64) by better light interception and effective carbohydrate utilisation under stress

2020 ◽  
Vol 47 (10) ◽  
pp. 891 ◽  
Author(s):  
Debarati Bhaduri ◽  
Koushik Chakraborty ◽  
A. K. Nayak ◽  
Mohammad Shahid ◽  
Rahul Tripathi ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Plant Biomass ◽  
Rice Cultivar ◽  
Antioxidant Enzyme Activities ◽  
Individual Plant ◽  
Submergence Tolerance ◽  
Light Penetration ◽  
Imaging Data ◽  
Seedling Vigour ◽  
Plant Plant

Besides genetic improvement for developing stress-tolerant cultivars, agronomic management may also add considerable tolerance against different abiotic stresses in crop plants. In the present study, we evaluated the effect of six different spacing treatments (S1: 10 × 10 cm; S2: 15 × 10 cm; S3:15 × 15 cm; S4:20 × 10 cm; S5: 20 × 15 cm; S6: 20 × 20 cm (row-row × plant-plant)) for improving submergence tolerance in rice. A high yielding submergence intolerant rice cultivar IR64 was tested against its SUB1 QTL introgressed counterpart (IR64-Sub1) for 12 days of complete submergence for different spacing treatments in field tanks. Relatively wider spaced plants showed higher individual plant biomass and early seedling vigour, which was particularly helpful for IR64 in increasing plant survival (by 150% in S6 over S1) under 12 days of submergence, whereas the improvement was less in IR64-Sub1 (13%). Underwater radiation inside the plant canopy, particularly beyond 40 cm water depth, was significantly greater in wider spacing treatments. Leaf senescence pattern captured by SPAD chlorophyll meter reading and chlorophyll fluorescence imaging data (Fm, Fv/Fm) taken at different time intervals after stress imposition suggested that there was lesser light penetration inside the canopy of closer spaced plants, and that it might hasten leaf senescence and damage to the photosynthetic system. The initial content of total non-structural carbohydrate (NSC) was higher in wider spaced plants of IR64, and also the rate of depletion of NSC was lesser compared with closer spaced plants. In contrast, there was not much difference in NSC depletion rate under different spacing in IR64-Sub1. Further, higher antioxidant enzyme activities in wider spaced plants (both IR64 and IR64-Sub1) after de-submergence indicated better stress recovery and improved tolerance. Taken together we found that wider spacing (row-row: 20 cm and plant-plant: 15 cm and more) can significantly improve submergence tolerance ability in rice, particularly in submergence intolerant non-Sub1 cultivar like IR64, perhaps due to better underwater light penetration, delayed leaf senescence and slower depletion of NSC reserve.

Postglacial vegetation dynamics at high elevation from Fairy Lake in the northern Greater Yellowstone Ecosystem, Montana, USA

2019 ◽  
Vol 92 (2) ◽  
pp. 365-380 ◽  
Author(s):  
James V. Benes ◽  
Virginia Iglesias ◽  
Cathy Whitlock
Keyword(s):  
Fire History ◽  
Late Glacial ◽  
High Elevation ◽  
Subalpine Forest ◽  
Greater Yellowstone Ecosystem ◽  
Southwestern Montana ◽  
History Of ◽  
Greater Yellowstone ◽  
High Elevations ◽  
Early Late

AbstractThe postglacial vegetation and fire history of the Greater Yellowstone Ecosystem is known from low and middle elevations, but little is known about high elevations. Paleoecologic data from Fairy Lake in the Bridger Range, southwestern Montana, provide a new high-elevation record that spans the last 15,000 yr. The records suggest a period of tundra-steppe vegetation prior to ca. 13,700 cal yr BP was followed by open Picea forest at ca. 11,200 cal yr BP. Pinus-Pseudotsuga parkland was present after ca. 9200 cal yr BP, when conditions were warmer/drier than present. It was replaced by mixed-conifer parkland at ca. 5000 cal yr BP. Present-day subalpine forest established at ca. 2800 cal yr BP. Increased avalanche or mass-wasting activity during the early late-glacial period, the Younger Dryas chronozone, and Neoglaciation suggest cool, wet periods. Sites at different elevations in the region show (1) synchronous vegetation responses to late-glacial warming; (2) widespread xerothermic forests and frequent fires in the early-to-middle Holocene; and (3) a trend to forest closure during late-Holocene cooling. Conditions in the Bridger Range were, however, wetter than other areas during the early Holocene. Across the Northern Rockies, postglacial warming progressed from west to east, reflecting range-specific responses to insolation-driven changes in climate.

Space and habitat use by the threatened Gaspé caribou in southeastern Quebec

1996 ◽  
Vol 74 (10) ◽  
pp. 1922-1933 ◽  
Author(s):  
Jean-Pierre Ouellet ◽  
Jean Ferron ◽  
Luc Sirois
Keyword(s):  
Home Range ◽  
Habitat Use ◽  
Adult Female ◽  
Rangifer Tarandus ◽  
High Elevation ◽  
Altitudinal Distribution ◽  
Alpine Habitat ◽  
Adult Females ◽  
Risk Of Predation ◽  
High Elevations

The space and habitat use patterns of the threatened Gaspé caribou (Rangifer tarandus caribou) were documented using telemetry. Between 1987 and 1992, 701 radiolocations were recorded, primarily for adult females (n = 28). Five habitats available to caribou (hardwood, immature, mature fir, mature spruce, alpine) are described and biomass of arboreal lichen, an important winter food source, is estimated. Regardless of sex and age, almost all locations (91%) were recorded within the limits of Gaspé Provincial Park. Home-range size of adult females averaged 148 km2 (convex polygon); 95% of adult female locations were within 107 km2 and 50% within 15 km2 (harmonic mean). Home-range sizes were small and did not vary seasonally or annually. Throughout the year caribou were located more frequently than expected at high elevations (> 915 m) and less frequently than expected at low elevations (0–685 m). Consequently, alpine habitat was used more frequently than expected. Caribou concentrated their activity in two distinct areas: the alpine plateaus of Mont Albert and Mont Jacques-Cartier. No caribou used both areas (with the exception of a lone female). These two caribou groups should be viewed as two subpopulations. The biomass of arboreal lichens was greatest in mature fir and spruce stands, with 50–60 kg/ha available at a height of 4 m. The altitudinal distribution of this resource may partly explain the strong selection of high-elevation sites made by caribou in winter. Our results also support the hypothesis that cow–calf groups remain at high elevations to reduce the risk of predation by coyotes (Canis latrans) and black bears (Ursus americanus). The proximity of mature forests and alpine habitat, at high elevations, in two areas of the park may explain the small extent of adult female home ranges and the segregation of Gaspé caribou into two groups.

scholarly journals Distribution of boreal toad populations in relation to estimated UV-B dose in Glacier National Park, Montana, USA

2006 ◽  
Vol 84 (1) ◽  
pp. 98-107 ◽  
Author(s):  
Blake R Hossack ◽  
Stephen A Diamond ◽  
Paul Stephen Corn
Keyword(s):  
National Park ◽  
Temporal Trends ◽  
Ground Level ◽  
High Elevation ◽  
Ultraviolet B ◽  
Glacier National Park ◽  
Embryo Survival ◽  
Breeding Sites ◽  
Forest Density ◽  
High Elevations

A recent increase in ultraviolet B radiation is one hypothesis advanced to explain suspected or documented declines of the boreal toad (Bufo boreas Baird and Girard, 1852) across much of the western USA, where some experiments have shown ambient UV-B can reduce embryo survival. We examined B. boreas occupancy relative to daily UV-B dose at 172 potential breeding sites in Glacier National Park, Montana, to assess whether UV-B limits the distribution of toads. Dose estimates were based on ground-level UV-B data and the effects of elevation, local topographic and vegetative features, and attenuation in the water column. We also examined temporal trends in surface UV-B and spring snowpack to determine whether populations are likely to have experienced increased UV-B exposure in recent decades. We found no support for the hypothesis that UV-B limits the distribution of populations in the park, even when we analyzed high-elevation ponds separately. Instead, toads were more likely to breed in water bodies with higher estimated UV-B doses. The lack of a detectable trend in surface UV-B since 1979, combined with earlier snow melt in the region and increasing forest density at high elevations, suggests B. boreas embryos and larvae likely have not experienced increased UV-B.

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