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

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

2020 ◽  
Author(s):  
Robert Shriver ◽  
Erin Campbell ◽  
Christopher Dailey ◽  
Heather Gaya ◽  
Abby Hill ◽  
...  
Keyword(s):  
Climate Change ◽  
Reproductive Output ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Landscape Position ◽  
Environmental Drivers ◽  
Lower Survival ◽  
Demographic Rates ◽  
Bluebunch Wheatgrass ◽  
Local Topography

Understanding the environmental drivers of demographic rates and population dynamics over space and time is critical for anticipating how species will respond to climate change. While the influence of temporal environmental variation and large environmental gradients are well recognized, less is known about how local topography and landscape position influence demography over small spatial scales. Here, we investigate how local landscape position (north- vs. south-facing aspects) influence the demographic rates and population growth of a common bunchgrass in western North America, bluebunch wheatgrass (Pseudoroegneria spicata), using 6 annual censuses measuring growth, survival, and reproductive output. We found notably lower survival on south facing slopes, particularly among smaller individuals. In contrast, south-facing slopes maintained comparatively high reproductive output in most years, measured both as spikes per plant and spikelets per spike. When we combined these data in demographic models, we found that lower survival among small individuals and greater reliance on reproduction mean south-facing slopes would generally have to maintain higher recruitment for a stable population. Our results highlight the important influence that landscape position and local topography can have in driving population trends. As conditions warm and dry with climate change (north-faces becoming similar to current south-facing slope conditions), bluebunch wheatgrass may become more reliant on reproduction to maintain viable populations and more sensitive to variability in recruitment.

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

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.

1588: The Bicalutamide Early Prostate Cancer Program: Findings of the North American Trial at 7.7 Years' Median Follow-Up

2006 ◽  
Vol 175 (4S) ◽  
pp. 511-512
Author(s):  
David G. McLeod ◽  
Ira Klimberg ◽  
Donald Gleason ◽  
Gerald Chodak ◽  
Thomas Morris ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
North American ◽  
Early Prostate Cancer ◽  
The North ◽  
Cancer Program
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