The Influence of Landscape Position on Temporal Variability in Four North American Ecosystems

1991 ◽  
Vol 138 (2) ◽  
pp. 355-378 ◽  
Author(s):  
T. K. Kratz ◽  
B. J. Benson ◽  
E. R. Blood ◽  
G. L. Cunningham ◽  
R. A. Dahlgren
Keyword(s):  
North American ◽  
Temporal Variability ◽  
Landscape Position

scholarly journals Local Landscape Position Impacts Demographic Rates in a Widespread North American Steppe Bunchgrass

2021 ◽  
Vol 102 (2) ◽  
Author(s):  
Robert K. Shriver ◽  
Erin Campbell ◽  
Christopher Dailey ◽  
Heather Gaya ◽  
Abby Hill ◽  
...  
Keyword(s):  
North American ◽  
Landscape Position ◽  
Demographic Rates

scholarly journals An assessment of temporal variability in mast seeding of North American Pinaceae

2021 ◽  
Vol 376 (1839) ◽  
Author(s):  
Jalene M. LaMontagne ◽  
Miranda D. Redmond ◽  
Andreas P. Wion ◽  
David F. Greene
Keyword(s):  
North American ◽  
Temporal Variability ◽  
Absolute Temperature ◽  
Mast Seeding ◽  
Weather Variables ◽  
Large Dataset ◽  
Development Cycle ◽  
Characteristic Features ◽  
Bud Initiation ◽  
July Temperature

Our overall objective is to synthesize mast-seeding data on North American Pinaceae to detect characteristic features of reproduction (i.e. development cycle length, serotiny, dispersal agents), and test for patterns in temporal variation based on weather variables. We use a large dataset ( n = 286 time series; mean length = 18.9 years) on crop sizes in four conifer genera ( Abies , Picea , Pinus , Tsuga ) collected between 1960 and 2014. Temporal variability in mast seeding (CVp) for 2 year genera ( Abies , Picea , Tsuga ) was higher than for Pinus (3 year), and serotinous species had lower CVp than non-serotinous species; there were no relationships of CVp with elevation or latitude. There was no difference in family-wide CVp across four tree regions of North America. Across all genera, July temperature differences between bud initiation and the prior year (Δ T ) was more strongly associated with reproduction than absolute temperature. Both CVp and Δ T remained steady over time, while absolute temperature increased by 0.09°C per decade. Our use of the Δ T model included a modification for Pinus , which initiates cone primordia 2 years before seedfall, as opposed to 1 year. These findings have implications for how mast-seeding patterns may change with future increases in temperature, and the adaptive benefits of mast seeding. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

scholarly journals Local landscape position impacts demographic rates in a widespread North American steppe bunchgrass

Ecosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Robert K. Shriver ◽  
Erin Campbell ◽  
Christopher Dailey ◽  
Heather Gaya ◽  
Abby Hill ◽  
...  
Keyword(s):  
North American ◽  
Landscape Position ◽  
Demographic Rates

Adaptation of the Connected Speech Test: Rerecording and Passage Equivalency

2020 ◽  
Vol 29 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Hasan K. Saleh ◽  
Paula Folkeard ◽  
Ewan Macpherson ◽  
Susan Scollie
Keyword(s):  
Speech Perception ◽  
North American ◽  
First Language ◽  
Intraclass Correlation ◽  
Normal Hearing ◽  
Connected Speech ◽  
Internal Reliability ◽  
Speech Test ◽  
The Mean ◽  
Unit Standard

Purpose The original Connected Speech Test (CST; Cox et al., 1987) is a well-regarded and often utilized speech perception test. The aim of this study was to develop a new version of the CST using a neutral North American accent and to assess the use of this updated CST on participants with normal hearing. Method A female English speaker was recruited to read the original CST passages, which were recorded as the new CST stimuli. A study was designed to assess the newly recorded CST passages' equivalence and conduct normalization. The study included 19 Western University students (11 females and eight males) with normal hearing and with English as a first language. Results Raw scores for the 48 tested passages were converted to rationalized arcsine units, and average passage scores more than 1 rationalized arcsine unit standard deviation from the mean were excluded. The internal reliability of the 32 remaining passages was assessed, and the two-way random effects intraclass correlation was .944. Conclusion The aim of our study was to create new CST stimuli with a more general North American accent in order to minimize accent effects on the speech perception scores. The study resulted in 32 passages of equivalent difficulty for listeners with normal hearing.

Sign in / Sign up

Export Citation Format

Share Document