A comparison of the life histories and growth patterns of populations of the salamander Ambystoma gracile (Baird) from permanent low-altitude and montane lakes

1976 ◽  
Vol 54 (12) ◽  
pp. 2098-2111 ◽  
Author(s):  
Gerald W. Eagleson
Keyword(s):  
High Altitude ◽  
Life Histories ◽  
Sexual Maturity ◽  
Larval Growth ◽  
Field Studies ◽  
Growth Patterns ◽  
Size At Metamorphosis ◽  
Low Altitude ◽  
High Altitude Lake ◽  
Sexually Mature

Laboratory and field studies were initiated to study the life-history patterns of populations of Ambystoma gracile from three permanent lakes located at different altitudes in southwestern British Columbia. Laboratory studies indicated clear differences between low- and high-altitude populations with respect to larval growth, timing of metamorphosis, size at metamorphosis, and the incidence of neoteny. Field studies indicated that low-altitude neotenous females became sexually mature at a length of 7.1 cm (snout to vent length, SVL); but owing to the shorter seasons within higher altitude lakes, neotenous females required more seasons to attain sexual maturity. High- and low-altitude males attained sexual maturity at 7.4-cm SVL, but a few smaller, sexually mature males were discovered within the high-altitude lake. Neotenous females reproduced annually within the low-altitude lake, but high-altitude neotenous females did not reproduce during successive years. Possible genetic adaptations to low and high altitudes are discussed.

scholarly journals A combination of genetic and phenotypic characterization of spring- and autumn-spawning herring suggests gene flow between populations

2020 ◽  
Author(s):  
Florian Berg ◽  
Hedda D Østgaard ◽  
Aril Slotte ◽  
Leif Andersson ◽  
Arild Folkvord
Keyword(s):  
Gene Flow ◽  
Life Histories ◽  
Larval Growth ◽  
Growth Patterns ◽  
Clupea Harengus ◽  
Spawning Season ◽  
Phenotypic Characterization ◽  
Otolith Microstructure ◽  
Complex Population ◽  
Population Structure And Dynamics

Abstract Atlantic herring (Clupea harengus) has complex population structure and dynamics including diverse life histories and spawning times with spring and autumn spawning as the most common modes. Originally, spawning herring were phenotypically identified based on their maturity development or otolith microstructure by determining seasonal specific larval growth patterns. Recently, genetic markers have revealed clear genetic differentiation between spring- and autumn-spawning populations. All three methods were applied to herring caught at the same locations during spring and autumn to determine the coherence of methods. In a selected subset, most herring (∼77%) had an otolith microstructure and genetic assignment coinciding with the phenotypically assigned spawning season. Non-spawning herring (<5%) that were classified as belonging to the current spawning season using genotyping and otolith-typing were assigned as skipped spawners. For ∼8% of spawning herring, the genetic and otolith assignment contradicted the phenotypically assigned spawning season, characteristic of straying individuals. Otolith-typing contradicted the genetic and phenotypical assignment in ∼7% of the cases, potentially representing individuals reuniting back to the spawning season favoured by their genotype. Although the viability of offspring from these individuals remains undocumented, it is suggested that the observed switching of spawning season may contribute to gene flow between herring populations.

Plasticity of metamorphic traits in a high-altitude toad: interactive effects of food level and temperature

2016 ◽  
Vol 37 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Tong Lei Yu ◽  
Michael Busam ◽  
Dong Li Wang ◽  
Kun Chen
Keyword(s):  
High Altitude ◽  
Food Supply ◽  
Larval Growth ◽  
Life Cycles ◽  
Larval Period ◽  
Interactive Effects ◽  
Food Level ◽  
Complex Life Cycles ◽  
Size At Metamorphosis ◽  
Lower Temperature

In organisms with complex life cycles, such as amphibians, morphological variation itself is strongly influenced by environmental factors and maternal effects. Although temperature and food level exert a strong influence on larval growth and development, little is known about the interacting effects of these factors on age and size at metamorphosis. In this study, plasticity in growth rates, larval mass, larval period, and body size at metamorphosis were experimentally examined for a high-altitude toad (Bufo minshanicus) under different combinations of temperature and food level. Larval period and mass at metamorphosis were sensitive to food level, and varied with temperature. At high food level, tadpoles reared at 29.8°C had shorter larval period lengths and larger mass at metamorphosis than those reared at 25.8 and 22.6°C, but not between 25.8 and 22.6°C. Interestingly, tadpoles at 29.8°C that were offered with a higher level of food supply achieved a larger size than those with a lower level of food supply; however, food supply did not affect body mass at the two lower temperature settings. Thus, the effects of food level were dependent on water temperature. Although there was high mortality at 29.8°C, surviving tadpoles have been much stronger to achieve faster growth and reach a larger mass at metamorphosis, which were positively correlated with juvenile survival and adult fecundity. Thus, under varied environmental conditions, we could say that there is more plasticity in development and growth of larvae in high altitude populations than in the same species or other species from low altitude populations.

Larval Behavior and Protective Implications for Sea Scallops and Surf Clams within the Middle Atlantic Bight: Part Two, Variability of Physical Environment and Larval Behaviors

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
Physical Environment ◽  
Climate Changes ◽  
Larval Growth ◽  
Growth Patterns ◽  
Larval Behavior ◽  
Larval Release ◽  
Physical Conditions ◽  
Climatic Variations ◽  
Middle Atlantic ◽  
Sea Scallops

Larval growth and settlement rates are important larval behaviors for larval protections. The variability of larval growthsettlement rates and physical conditions for 2006-2012 and in the future with potential climate changes was studied using the coupling ROMS-IMBs, and new temperature and current indexes. Forty-four experimental cases were conducted for larval growth patterns and release mechanisms, showing the spatial, seasonal, annual, and climatic variations of larval growthsettlement rates and physical conditions, demonstrating that the slight different larval temperature-adaption and larval release strategies made difference in larval growth-settlement rates, and displaying that larval growth and settlement rates highly depended upon physical conditions and were vulnerable to climate changes.

scholarly journals Effect of High-Altitude Environment on Driving Safety: A Study on Drivers’ Mental Workload, Situation Awareness, and Driving Behaviour

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xinyan Wang ◽  
Wu Bo ◽  
Weihua Yang ◽  
Suping Cui ◽  
Pengzi Chu
Keyword(s):  
High Altitude ◽  
Situation Awareness ◽  
Mental Workload ◽  
Mediating Effect ◽  
Driving Safety ◽  
Risky Driving ◽  
Driving Behaviour ◽  
Driving Risk ◽  
Low Altitude ◽  
The Relationship

This study aims to analyze the effect of high-altitude environment on drivers’ mental workload (MW), situation awareness (SA), and driving behaviour (DB), and to explore the relationship among those driving performances. Based on a survey, the data of 356 lowlanders engaging in driving activities at Tibetan Plateau (high-altitude group) and 341 lowlanders engaging in driving activities at low altitudes (low-altitude group) were compared and analyzed. The results suggest that the differences between the two groups are noteworthy. Mental workload of high-altitude group is significantly higher than that of low-altitude group, and their situation awareness is lower significantly. The possibility of risky driving behaviours for high-altitude group, especially aggressive violations, is higher. For the high-altitude group, the increase of mental workload can lead to an increase on aggressive violations, and the situation understanding plays a full mediating effect between mental workload and aggressive violations. Measures aiming at the improvement of situation awareness and the reduction of mental workload can effectively reduce the driving risk from high-altitude environment for lowlanders.

scholarly journals Effect of high altitude on human placental amino acid transport

2020 ◽  
Vol 128 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Owen. R. Vaughan ◽  
Fredrick Thompson ◽  
Ramón. A. Lorca ◽  
Colleen G. Julian ◽  
Theresa L. Powell ◽  
...  
Keyword(s):  
Birth Weight ◽  
Amino Acid ◽  
High Altitude ◽  
Sea Level ◽  
Amino Acid Transport ◽  
Acid Uptake ◽  
Acid Transport ◽  
Transport Capacity ◽  
System A ◽  
Low Altitude

Women residing at high altitudes deliver infants of lower birth weight than at sea level. Birth weight correlates with placental system A-mediated amino acid transport capacity, and severe environmental hypoxia reduces system A activity in isolated trophoblast and the mouse placenta. However, the effect of high altitude on human placental amino acid transport remains unknown. We hypothesized that microvillous membrane (MVM) system A and system L amino acid transporter activity is lower in placentas of women living at high altitude compared with low-altitude controls. Placentas were collected at term from healthy pregnant women residing at high altitude (HA; >2,500 m; n = 14) or low altitude (LA; <1,700 m; n = 14) following planned, unlabored cesarean section. Birth weight, but not placenta weight, was 13% lower in HA pregnancies (2.88 ± 0.11 kg) compared with LA (3.30 ± 0.07 kg, P < 0.01). MVM erythropoietin receptor abundance, determined by immunoblot, was greater in HA than in LA placentas, consistent with lower placental oxygen levels at HA. However, there was no effect of altitude on MVM system A or L activity, determined by Na+-dependent [14C]methylaminoisobutyric acid uptake and [3H]leucine uptake, respectively. MVM abundance of glucose transporters (GLUTs) 1 and 4 and basal membrane GLUT4 were also similar in LA and HA placentas. Low birth weights in the neonates of women residing at high altitude are not a consequence of reduced placental amino acid transport capacity. These observations are in general agreement with studies of IUGR babies at low altitude, in which MVM system A activity is downregulated only in growth-restricted babies with significant compromise. NEW & NOTEWORTHY Babies born at high altitude are smaller than at sea level. Birth weight is dependent on growth in utero and, in turn, placental nutrient transport. We determined amino acid transport capacity in placentas collected from women resident at low and high altitude. Altitude did not affect system A amino acid transport across the syncytiotrophoblast microvillous membrane, suggesting that impaired placental amino acid transport does not contribute to reduced birth weight in this high-altitude population.

scholarly journals Seasonal and Altitudinal Prevalence of Fascioliasis in Buffalo in Eastern Nepal

2018 ◽  
Vol 4 ◽  
pp. 48-53
Author(s):  
Ramesh Prasad Sah ◽  
Hari Kumar Prasai ◽  
Jiban Shrestha ◽  
Md Hasanuzzaman Talukder ◽  
AKM Anisur Rahman ◽  
...  
Keyword(s):  
High Risk ◽  
High Altitude ◽  
Sea Level ◽  
Rainy Season ◽  
Meat Production ◽  
Parasitic Diseases ◽  
Sedimentation Technique ◽  
Risk Period ◽  
Pasture Contamination ◽  
Low Altitude

Buffalo is the most important livestock commodities for milk, meat production and several other multipurpose uses distributed densely from southern tarai to northern mid-hills in Nepal. Among several internal parasitic diseases fascioliasis is highly economic one caused by Fasciola in buffaloes. However, there are only few studies carried on prevalence of fascioliasis emphasizing buffaloes in relation to seasonal (summer and rainy, and winter) and altitudinal variations. Therefore, we examined prevalence of fascioliasis seasonally and vertically. For the purpose, we selected two districts of eastern Nepal and sampled from low altitude area known as Madhesha ranging from 175-200, Dhankuta from 800-1200 m, and Murtidhunga from 1800-2200 m elevation from the sea level, representing tarai, mid hills and high hills, respectively. Altogether from February 2013 to January 2014 at every two months interval we collected 798 fecal samples from buffaloes; 282 from Murtidhunga, 239 from Dhankuta and 277 from Madhesha. The samples were examined microscopically for the presence of Fasciola eggs using sedimentation technique. Results showed that overall prevalence of fascioliasis in buffaloes was 39.9% (319/798), ranging highest 42.6%in Madhesha followed by 39.7% in Murtidhunga and 37.2% in Dhankuta, respectively. The prevalence of fascioliasis was found to be significantly (p <0.05) high in winter (44.9%) comparing to rainy season (34.4%). The prevalence of fascioliasis in buffaloes was relatively higher in low altitude than high altitude, although it was not statistically significant (p <0.05). In our findings the female buffaloes showed higher prevalence for fascioliasis than in male. Since the fascioliasis in buffaloes is highly endemic, thus strategic deworming in high risk period is recommended along with measure to prevent pasture contamination with buffalo feces.

scholarly journals Morphological variation in Leptorhynchos squamatus (Gnaphalieae: Asteraceae)

2002 ◽  
Vol 15 (2) ◽  
pp. 205 ◽  
Author(s):  
Christina Flann ◽  
Pauline Y. Ladiges ◽  
Neville G. Walsh
Keyword(s):  
High Altitude ◽  
Morphological Variation ◽  
Environmental Conditions ◽  
Leaf Size ◽  
Alpine Plants ◽  
The Other ◽  
Herbarium Specimens ◽  
South Eastern ◽  
Eastern Australia ◽  
Low Altitude

A study of morphological variation in Leptorhynchos squamatus (Labill.) Less. across its range in south-eastern Australia was undertaken to test the hypothesis that L. squamatus includes two taxa. Phenetic pattern analyses of both field-collected and herbarium specimens on the basis of morphology confirmed two major groups. Bract, cypsela, pappus bristle and leaf characters were particularly important in separating the two groups. The taxa are separated by altitude differences with one being a low-altitude plant found in many habitats and the other being a high-altitude taxon that is a major component of alpine meadows. Lowland plants have dark bract tips, fewer and wider pappus bristles than alpine plants, papillae on the cypselas and more linear leaves. A somewhat intermediate population from the Major Mitchell Plateau in the Grampians shows some alpine and some lowland characters but is included in the lowland taxon. Seeds from five populations (two alpine, two lowland and Major Mitchell) were germinated and plants grown for 18 weeks under four controlled sets of environmental conditions. The experiment showed that leaf size and some other characters are affected by environmental conditions, but that there are underlying genetic differences between the lowland and alpine forms. Leptorhynchos squamatus subsp. alpinus Flann is described here to accommodate the highland taxon.

scholarly journals Species Richness and Traditional Knowledge of Macrofungi (Mushrooms) in the Awing Forest Reserve and Communities, Northwest Region, Cameroon

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Tonjock Rosemary Kinge ◽  
Nkengmo Apiseh Apalah ◽  
Theobald Mue Nji ◽  
Ache Neh Acha ◽  
Afui Mathias Mih
Keyword(s):  
High Altitude ◽  
Traditional Knowledge ◽  
Group Discussion ◽  
Descriptive Statistics ◽  
Microsoft Excel ◽  
Forest Reserve ◽  
Pictorial Presentation ◽  
Mycorrhizal Associations ◽  
Low Altitude ◽  
Northwest Region

Macrofungi are diverse in their uses as food and medicine and several species serve as decomposers and also form mycorrhizal associations. Awing forest reserve is diverse in plants and fungi species. However, no work has been carried out to assess the diversity and traditional knowledge of macrofungi in the area. Diversity surveys were carried out in three altitudes using transects of 50×20 m for six months in 2015. Ethnomycology studies were carried out in fifteen communities using focus group discussion, pictorial presentation, and questionnaires. The data was analyzed using descriptive statistics in Microsoft Excel 2010. Seventy-five species belonging to thirty families were identified by morphology. Thirty-six species were found only in the low altitude, 16 in the mid altitude, and 16 species in high altitude. One species was common to low and mid altitude and also low and high altitude; five species were common to mid and high altitude while there was no species common to all three altitudes. The indigenes of the Awing communities commonly called mushroom “Poh” and use it mainly as food and medicine and in mythological beliefs. The most utilized species as food and medicine included Termitomyces titanicus, Laetiporus sulphureus, and Ganoderma sp.

Sign in / Sign up

Export Citation Format

Share Document