scholarly journals Variation in the seasonal germination niche across an elevational gradient: the role of germination cueing in current and future climates

2020 ◽  
Vol 107 (2) ◽  
pp. 350-363 ◽  
Author(s):  
Jennifer R. Gremer ◽  
Alec Chiono ◽  
Elena Suglia ◽  
Megan Bontrager ◽  
Lauren Okafor ◽  
...  
Keyword(s):  
Elevational Gradient ◽  
Germination Niche

scholarly journals Paleoecological affinities of selected Miocene megafossil taxa from the northern intermountain region based on palynological modeling

1992 ◽  
Vol 6 ◽  
pp. 96-96
Author(s):  
Patrick F. Fields ◽  
Ralph E. Taggart
Keyword(s):  
Elevational Gradient ◽  
Ecological Significance ◽  
Palynological Analysis ◽  
Palynological Data ◽  
Paleoclimatic Reconstruction ◽  
Patterns Of Distribution ◽  
Lower Elevation ◽  
Wide Range ◽  
Intermountain Region

Palynological analysis of stratigraphically-controlled samples from a number of localities in the Succor Creek area of the Oregon-Idaho boundary, the Stinking Water flora of eastern Oregon, and the Trapper Creek flora of southern Idaho has proved to be a valuable interpretive tool in the study of these mid-Miocene plant assemblages. Models derived from analysis of the Succor Creek data suggest: 1) paleotopographic trends, 2) patterns of distribution of major forest elements, 3) the role of disturbance and succession, and 4) limits for paleoclimatic reconstruction. These have proved consistent with patterns of megafossil representation at Succor Creek and both megafossil and palynological data at Stinking Water and Trapper Creek. Such models also appear useful in the refinement of ecological affinities of a number of megafossil taxa which occur in these and other Neogene assemblages throughout the northern Intermountain region.Some taxa are quite specific in their affinities, both in terms of vegetational maturity and elevational zonation. Species of Abies, Picea, Pseudotsuga, Thuja and Tsuga appear characteristic of ecologically mature forests at somewhat higher elevations. Such forests are rare at Stinking Water, are best developed in the southern part of the Succor Creek region, and represent the “climax” forests at Trapper Creek. In contrast, broad-leaved taxa, including species of Castanea, Castanopsis, Nyssa, and most Quercus, are reliable indicators of ecologically mature, lower elevation forests.The ecological significance of a number of mixed-mesophytic taxa, including species of Carya, Juglans, Liquidambar, Pterocarya, Sassafras, Tilia, Ulmus, and Zelkova, is ambiguous. Broad-leaved deciduous assemblages dominated by these plants occur as mid-seral recovery stages over a wide range of elevation from lowlands to higher slopes. Ecologically mature forests of these trees tend to be found only at intermediate elevations. At lower elevations they are largely, but not exclusively, replaced in later seral stages by the ecologically mature, low-elevation taxa noted previously; while at higher elevations they are replaced by conifers.Some taxa, most notably Equisetum, Glyptostrobus, Osmunda, and Typha are restricted to very wet habitats, irrespective of elevation. The shade-intolerant Typha forms ephemeral marshes that are rapidly replaced by Glyptostrobus swamps. Lake margins (and riparian settings), over a wide elevational gradient, are characterized by thickets of Acer, Alnus, Arbutus, Populus, Quercus simulata, “Quercus” eoprinus, and Salix. Locally Sequoia occurs in upland settings (i.e. at Payette, Idaho), while Glyptostrobus is more common in lowlands (Stinking Water and northern Succor Creek localities), but can occur in lower frequencies at any paleoelevation. Some taxa, such as Acer medianum appear to be characteristic of mid-seral recovery stages in these wet habitats.

scholarly journals Elevational Zonation and the Phylogenetic Relationships of the Henicorhina Wood-Wrens

The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 119-134 ◽  
Author(s):  
Caroline Dingle ◽  
Irby J. Lovette ◽  
Chris Canaday ◽  
Thomas B. Smith
Keyword(s):  
Central America ◽  
Dna Sequences ◽  
Genetic Relationships ◽  
Elevational Gradient ◽  
Species Status ◽  
Ecological Diversification ◽  
Evolutionary Origins ◽  
The Andes

Abstract The Henicorhina wood-wren complex consists of three taxonomic species. Two of these, the Gray-breasted Wood-Wren (Henicorhina leucophrys) and the White-breasted Wood-Wren (H. leucosticta), are widespread throughout Central America and northern South America, with leucophrys occurring at higher elevations in regions where both occur. A third, recently described, species—the Bar-winged Wood-Wren (H. leucoptera)—occurs only in several isolated cordilleras in southeastern Ecuador and northeastern Peru, where it replaces the Gray-breasted Wood-Wren at the highest elevations. We used mitochondrial DNA sequences to explore the phylo-genetic relationships among populations of these taxa and to draw inferences about the evolutionary origins of elevational zonation. We found substantial mitochondrial diversity within both leucophrys and leucosticta. Differentiation across the Andes in leucophrys was negligible, but populations from Central America and from northwestern Ecuador showed substantial differentiation. Three highly differentiated haplotype groups were also present in leucosticta, corresponding to populations in the eastern Andean lowlands, Central America, and the Chocó region of northwestern Ecuador; these populations may each warrant taxonomic species status. Bar-winged haplo-types nested within the mitochondrially diverse leucosticta group, where they were most closely allied to the geographically distant Chocó haplotypes. This leucoptera-leucosticta affinity is not consistent with previous inferences, based on plumage and behavioral similarities, that grouped leucoptera and leucophrys as sister species. These reconstructions refute the hypothesis that elevational zonation in this clade originated from in situ speciation along an elevational gradient, and instead highlight the role of complex changes in geographic distributions in fostering phylogenetic and ecological diversification. Reemplazos Altitudinales y Relaciones Filogenéticas en el Género Henicorhina (Troglodytidae)

Role of Annual Leaf Carbon Balance in the Distribution of Plant Species along an Elevational Gradient

1979 ◽  
Vol 140 (3) ◽  
pp. 288-294 ◽  
Author(s):  
James A. Bunce ◽  
Brian F. Chabot ◽  
Lee N. Miller
Keyword(s):  
Plant Species ◽  
Carbon Balance ◽  
Elevational Gradient

scholarly journals Telomere length covaries with age across an elevational gradient in a Mediterranean lizard

2019 ◽  
Author(s):  
Pablo Burraco ◽  
Mar Comas ◽  
Senda Reguera ◽  
Francisco Javier Zamora-Camacho ◽  
Gregorio Moreno-Rueda
Keyword(s):  
Life History ◽  
Body Size ◽  
Telomere Length ◽  
Body Condition ◽  
Life History Traits ◽  
Elevational Gradient ◽  
Habitat Characteristics ◽  
Tail Autotomy ◽  
Non Linear

AbstractThe timing of organisms’ senescence is developmentally programmed but also shaped by the interaction between environmental inputs and life-history traits. In ectotherms, ageing dynamics are still poorly understood despite their particularities concerning thermoregulation, regeneration capacity, or growth trajectory. Here, we investigate the role of life-history traits such as age, sex, body size, body condition, and tail autotomy (i.e self-amputation) in shaping telomere length of six populations of the Algerian sand lizard (Psammodromus algirus) distributed across an elevational gradient from 300 to 2500 meters above the sea level. Additionally, we show in a review table the available information on reptiles’ telomere length. We found that telomeres elongated with lizards’ age. We also observed that body size and age class showed a positive relationship, suggesting that cell replication did not shorten lizards’ telomeres by itself. Elevation affected telomere length in a non-linear way, a pattern that mirrored the variation in age structure across elevation. Telomere length was unaffected by tail autotomy, and was sex-independent, but positively correlated with body condition. Our results show that telomeres elongate throughout the first four years of lizards’ lifetime, a process that stress the role of telomerase in maintaining ectothermic telomeres, and, likely, in extending lifespan in organisms with indeterminate growth. Regarding the non-linear impact that elevation had on telomere length of lizards, our results suggest that habitat (mainly temperature) and organisms’ condition might play a key role in regulation ageing rate. Our findings emphasize the relevance of understanding species’ life histories (e.g. age and body condition) and habitat characteristics for fully disentangling the causes and consequences of lifespan trajectory.

The role of selection and historical factors in driving population differentiation along an elevational gradient in an island bird

2016 ◽  
Vol 29 (4) ◽  
pp. 824-836 ◽  
Author(s):  
J. A. M. Bertrand ◽  
B. Delahaie ◽  
Y. X. C. Bourgeois ◽  
T. Duval ◽  
R. García-Jiménez ◽  
...  
Keyword(s):  
Population Differentiation ◽  
Elevational Gradient ◽  
Historical Factors

scholarly journals The Role of Inter- and Intraspecific Variations in Grassland Plant Functional Traits along an Elevational Gradient in a Mediterranean Mountain Area

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 359
Author(s):  
Letizia Di Biase ◽  
Simone Fattorini ◽  
Maurizio Cutini ◽  
Alessandro Bricca
Keyword(s):  
Plant Traits ◽  
Central Italy ◽  
Seed Mass ◽  
Elevational Gradient ◽  
Climatic Conditions ◽  
Relative Role ◽  
Mountain Area ◽  
Local Conditions ◽  
Intraspecific Variations

Elevational gradients offer special opportunities to investigate the relative role of intraspecific and interspecific trait variations in relation to stress gradients. We used an altitudinal gradient in the Mediterranean (Mt Velino, Central Italy) to study (1) how community-weighted means (CWM) and nonweighted means (CM) vary with elevation for plant height, specific leaf area, and seed mass; and (2) how variation patterns differ for inter- and intraspecific functional variability. We tested (1) if elevation influences community functional composition on the basis of the adaptive value of plant traits and (2) if the latter shows intraspecific variations according to the species’ ability to cope with local conditions. We found that different traits showed different patterns, which can be linked to the function they express. Differences between communities were influenced more by differences between their traits (CM) than by the relative species coverage (CWM). Both highest and lowest elevations were the most selective due to their particularly severe climatic conditions. Intermediate elevations were the most favorable thanks to less constraining climatic conditions. Interspecific trait variability was the most relevant component, indicating a low plant ability to cope with environmental variations through phenotypic plasticity.

The role of environment and mid-domain effect on moth species richness along a tropical elevational gradient

2007 ◽  
Vol 16 (2) ◽  
pp. 205-219 ◽  
Author(s):  
Gunnar Brehm ◽  
Robert K. Colwell ◽  
Jürgen Kluge
Keyword(s):  
Species Richness ◽  
Elevational Gradient ◽  
Moth Species

scholarly journals Patterns of host and flea communities along an elevational gradient in Colorado

2014 ◽  
Vol 92 (5) ◽  
pp. 433-442 ◽  
Author(s):  
S.P. Maher ◽  
R.M. Timm
Keyword(s):  
Small Mammal ◽  
Species Interactions ◽  
Environmental Changes ◽  
Elevational Gradient ◽  
Flea Species ◽  
Front Range ◽  
Local Effects ◽  
Parasite Communities ◽  
Diversity Metrics

Patterns in community composition across a landscape are the result of mechanistic responses and species interactions. Interactions between hosts and parasites have additional complexity because of the contingency of host presence and interactions among parasites. To assess the role of environmental changes within host and parasite communities, we surveyed small mammals and their fleas over a dynamic elevational gradient in the Front Range in Colorado, USA. Communities were characterized using several richness and diversity metrics and these were compared using a suite of frequentist and randomization approaches. We found that flea species richness was related to the number of host species based upon rarefaction, but no patterns in richness with elevation were evident. Values of diversity measures increased with elevation, representing that small-mammal and flea communities were more even upslope, yet turnover in composition was not related to examined variables. The results suggest there are strong local effects that drive these small-mammal and flea communities, although the breadth of flea species is tied to host availability.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management
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