Microsite- and age-specific processes controlling natural populations of Acer saccharum at cliff edges

1991 ◽  
Vol 69 (3) ◽  
pp. 552-559 ◽  
Author(s):  
R. M. Bartlett ◽  
U. Matthes-Sears ◽  
D. W. Larson
Keyword(s):  
Spatial Distribution ◽  
Environmental Conditions ◽  
Acer Saccharum ◽  
Deciduous Forest ◽  
Natural Populations ◽  
Visible Injury ◽  
Niagara Escarpment ◽  
Spatial And Seasonal Variation ◽  
Dependent Processes ◽  
Age Structures

Along cliff edges of the Niagara Escarpment in Ontario, Canada, Acer saccharum Marsh, is rarely found, but within 5 m of the cliff edge it becomes the dominant species of a rich deciduous forest on the plateau. To discover how age-dependent and microsite-dependent processes combine to control the spatial distribution of this species along the environmental gradient, age structures of natural seedlings and saplings between 1 and 25 years old were investigated over a three-year period. Mortality rates over the monitoring period were highest in 1-year-old seedlings and decreased gradually as age approached 10 years. Both spatial and seasonal variation in environmental conditions affected 1-year-old seedlings most, and these effects declined as seedling age increased. The distribution of types of visible injury preceding death in the 1-year-old seedlings suggested that both drought and herbivory influenced survivorship in this species, but to different degrees at different positions on the gradient. Lower seedling heights closer to the cliff edge in 1- to 10-year-old seedlings suggested that environmental conditions constrained productivity and survival. These results clearly demonstrate that variation in age structures along the gradient was determined by both age- and microsite-dependent processes and that these both contribute to the spatial distribution pattern of A. saccharum. Key words: life tables, survivorship, mortality, cliff, distribution, Acer saccharum, Niagara Escarpment.

Organization of the Niagara Escarpment cliff community. II. Characterization of the physical environment

1990 ◽  
Vol 68 (9) ◽  
pp. 1931-1941 ◽  
Author(s):  
R. M. Bartlett ◽  
U. Matthes-Sears ◽  
D. W. Larson
Keyword(s):  
Soil Moisture ◽  
Physical Environment ◽  
Acer Saccharum ◽  
Environmental Gradient ◽  
Deciduous Forest ◽  
Thuja Occidentalis ◽  
Active Radiation ◽  
Niagara Escarpment ◽  
Forest Habitats

In cliff-edge forests along the Niagara Escarpment, an array of species, including Thuja occidentals, is restricted to the cliff edge while different species, including Acer saccharum, are increasingly dominant away from the cliff on the plateau. This paper presents detailed analyses of 13 components of the physical environment, measured over an 18-month period, as they change across the plateau and towards the cliff edge. Statistically significant differences between the cliff-edge habitat and the adjacent deciduous forest were found in most of the 13 variables, and the results indicate a strong environmental gradient between the cliff edge and deciduous forest habitats. Lower and more rapidly fluctuating soil moisture levels combined with low photosynthetically active radiation at the cliff edge suggest that conditions there are frequently more severe for plants than in the deciduous forest in summer. Additionally, the cliff edge was snow free during the winter and the soils were frozen for a more protracted period than the deciduous forest soils. Soil and litter depths decreased significantly from the deciduous forest toward the cliff edge. The effects of these differences are discussed with reference to the characteristics of species that dominate the deciduous and coniferous cliff-edge zones. Key words: cliff, gradient, Thuja occidentalis, Acer saccharum, microclimate, Niagara Escarpment.

scholarly journals The sources of sex differences in aging in annual fishes

2020 ◽  
Author(s):  
Martin Reichard ◽  
Radim Blažek ◽  
Jakub Žák ◽  
Petr Kačer ◽  
Oldřich Tomášek ◽  
...  
Keyword(s):  
Sex Differences ◽  
Social Environment ◽  
Social Factors ◽  
Environmental Conditions ◽  
Natural Populations ◽  
Experimental Results ◽  
Survival Difference ◽  
Captive Populations ◽  
Baseline Mortality ◽  
In The Wild

AbstractSex differences in lifespan and aging are widespread among animals, with males usually the shorter-lived sex. Despite extensive research interest, it is unclear how lifespan differences between the sexes are modulated by genetic, environmental and social factors. We combined comparative data from natural populations of annual killifishes with experimental results on replicated captive populations, showing that females consistently outlived males in the wild. This sex-specific survival difference persisted in social environment only in two most aggressive species, and ceased completely when social and physical contacts were prevented. Demographically, neither an earlier start nor faster rate of aging accounted for shorter male lifespans, but increased baseline mortality and the lack of mortality deceleration in the oldest age shortened male lifespan. The sexes did not differ in any measure of functional aging we recorded. Overall, we demonstrate that sex differences in lifespan and aging may be ameliorated by modulating social and environmental conditions.

scholarly journals Spatial distribution of spruce trees in the nature reserve 'Jankove bare' on mt. Kopaonik

2009 ◽  
pp. 191-204
Author(s):  
Branko Stajic ◽  
Milivoj Vuckovic ◽  
Marko Smiljanic
Keyword(s):  
Spatial Distribution ◽  
Tree Growth ◽  
Environmental Conditions ◽  
National Park ◽  
Nature Reserve ◽  
Distance Methods ◽  
Study Results

The methodology and applicability of the study of spatial distribution of trees in Serbian forestry have been insufficiently reported and presented. This paper, based on mathematical?statistical principles, analyses the method of spatial distribution of spruce trees in the Nature Reserve 'Jankove Bare' in the National Park 'Kopaonik'. The following methods in the group of distance methods were applied: Kotar's method (1993), T2?method, and the index of distance dispersion (Johnson, Zimmer, 1985). The study results in a pure uneven-aged spruce stand based on all three methods showed that spruce trees are randomly distributed over the stand area. Therefore, environmental conditions in the study stand can be regarded as homogeneous and equally suitable for tree growth, and there are no significant interactions between the trees, which could cause a higher competition between the trees for nutrients, water, etc.

scholarly journals Variation in Recombination Rate Is Shaped by Domestication and Environmental Conditions in Barley

2019 ◽  
Vol 36 (9) ◽  
pp. 2029-2039 ◽  
Author(s):  
Steven Dreissig ◽  
Martin Mascher ◽  
Stefan Heckmann
Keyword(s):  
Environmental Conditions ◽  
Recombination Rate ◽  
Wild Barley ◽  
Natural Populations ◽  
Recombination Rates ◽  
Distal Chromosome ◽  
Positive Linear Correlation ◽  
Short And Long Term ◽  
Underlying Mechanisms ◽  
Chromosome Regions

Abstract Meiotic recombination generates genetic diversity upon which selection can act. Recombination rates are highly variable between species, populations, individuals, sexes, chromosomes, and chromosomal regions. The underlying mechanisms are controlled at the genetic and epigenetic level and show plasticity toward the environment. Environmental plasticity may be divided into short- and long-term responses. We estimated recombination rates in natural populations of wild barley and domesticated landraces using a population genetics approach. We analyzed recombination landscapes in wild barley and domesticated landraces at high resolution. In wild barley, high recombination rates are found in more interstitial chromosome regions in contrast to distal chromosome regions in domesticated barley. Among subpopulations of wild barley, natural variation in effective recombination rate is correlated with temperature, isothermality, and solar radiation in a nonlinear manner. A positive linear correlation was found between effective recombination rate and annual precipitation. We discuss our findings with respect to how the environment might shape effective recombination rates in natural populations. Higher recombination rates in wild barley populations subjected to specific environmental conditions could be a means to maintain fitness in a strictly inbreeding species.

Developing Automated Spectral Analysis Tools for Interstellar Features Extractionto Support Construction of the 3D ISM Map

2017 ◽  
Vol 12 (S330) ◽  
pp. 243-244
Author(s):  
L. Puspitarini ◽  
R. Lallement ◽  
A. Monreal-Ibero ◽  
H.-C. Chen ◽  
H. L. Malasan ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Spatial Distribution ◽  
Spatial Resolution ◽  
Environmental Conditions ◽  
Equivalent Width ◽  
Global Analysis ◽  
Line Of Sight ◽  
Absorption Data ◽  
Diffuse Interstellar Bands ◽  
Automated Spectral Analysis

AbstractOne of the ways to obtain a detailed 3D ISM map is by gathering interstellar (IS) absorption data toward widely distributed background target stars at known distances (line-of-sight/LOS data). The radial and angular evolution of the LOS measurements allow the inference of the ISM spatial distribution. For a better spatial resolution, one needs a large number of the LOS data. It requires building fast tools to measure IS absorption. One of the tools is a global analysis that fit two different diffuse interstellar bands (DIBs) simultaneously. We derived the equivalent width (EW) ratio of the two DIBs recorded in each spectrum of target stars. The ratio variability can be used to study IS environmental conditions or to detect DIB family.

scholarly journals Warmer temperatures attenuate the classic offspring number and reproductive investment trade-off in the common lizard, Zootoca vivipara

2016 ◽  
Vol 12 (6) ◽  
pp. 20160101 ◽  
Author(s):  
Alexis Rutschmann ◽  
Donald B. Miles ◽  
Jean Clobert ◽  
Murielle Richard
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Life History Traits ◽  
Natural Populations ◽  
Trade Off ◽  
Offspring Number ◽  
Common Lizard ◽  
Trade Offs ◽  
Zootoca Vivipara ◽  
The Common

Life-history traits involved in trade-offs are known to vary with environmental conditions. Here, we evaluate the response of the trade-off between ‘offspring number’ versus ‘energy invested per offspring’ to ambient temperature in 11 natural populations of the common lizard, Zootoca vivipara . We provide evidence at both the intra- and interpopulation levels that the trade-off is reduced with an increase in air temperature. If this effect enhances current individual fitness, it may lead to an accelerated pace of life in warmer environments and could ultimately increase adult mortality. In the context of global warming, our results advocate the need for more studies in natural populations to explore interactions between life-history traits' trade-offs and environmental conditions.

Small-scale heterogeneity in temperate forest canopy arthropods: stratification of spider and beetle assemblages

2012 ◽  
Vol 144 (4) ◽  
pp. 526-537 ◽  
Author(s):  
Kathleen R. Aikens ◽  
Christopher M. Buddle
Keyword(s):  
Spatial Variation ◽  
Acer Saccharum ◽  
Forest Canopy ◽  
Deciduous Forest ◽  
Abiotic Factors ◽  
Small Scale ◽  
Eastern Canada ◽  
Sugar Maples ◽  
Beetle Assemblages ◽  
The Vertical Distribution

AbstractVertical gradients in biotic and abiotic factors may create small-scale spatial variation in arthropod communities, a phenomenon that continues to be understudied. We investigated heterogeneity in the vertical distribution of spider and beetle assemblages in the canopy of sugar maples (Acer saccharum Marshall) (Aceraceae) in a deciduous forest in eastern Canada. Comparisons across four strata (understorey [UN] through upper canopy [UC] crown) documented variation in density, diversity, and species composition. Density of all common families decreased significantly with height and overall species richness of both spiders and beetles was highest in the UN and lowest in the UC crown. We observed greater spatial variation in spider assemblages compared with beetle assemblages and documented differences in spider guild structure: web-spinning spiders were most common in the UN and jumping spiders dominated the canopy. Our results suggest that arthropod assemblages are not homogeneous with respect to vertical space and that heterogeneity exists even at the scale of several metres.

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