Deer density and plant palatability predict shrub cover, richness, diversity and aboriginal food value in a North American archipelago

2014 ◽  
Vol 20 (12) ◽  
pp. 1368-1378 ◽  
Author(s):  
P. Arcese ◽  
R. Schuster ◽  
L. Campbell ◽  
A. Barber ◽  
T. G. Martin
2021 ◽  
Author(s):  
Katie Moriarty ◽  
Joel Thompson ◽  
Matthew Delheimer ◽  
Brent Barry ◽  
Mark Linnell ◽  
...  

AbstractBackgroundA suite of mammalian species have experienced range contractions following European settlement and post-settlement development of the North American continent. For example, while North American martens (American marten, Martes americana; Pacific marten, M. caurina) generally have a broad range across northern latitudes, local populations have experienced substantial reductions in distribution and some extant populations are small and geographically isolated. The Humboldt marten (M. c. humboldtensis), a subspecies of Pacific marten that occurs in coastal Oregon and northern California, was recently designated as federally threatened in part due to its reduced distribution. To inform strategic conservation actions, we assessed Humboldt marten occurrence by compiling all known records from their range.MethodsWe compiled Humboldt marten locations since their rediscover to present (1,692 marten locations, 1996-2020). We spatially-thinned locations to 500-m to assess correlations with variables across contemporary Humboldt marten distribution (n=384). Using maximum entropy modeling (Maxent), we created distribution models with variables optimized for spatial scale; pre-selected scales were associated with marten ecology (50 to 1170 m radius). Marten locations were most correlated with abiotic factors (e.g., precipitation), which are unalterable and therefore uninformative within the context of restoration or management actions. Thus, we created variables to focus on hypothesized marten habitat relationships, including understory conditions such as predicted suitability of shrub species.ResultsHumboldt marten locations were positively associated with increased shrub cover (salal (Gautheria shallon), mast producing trees), increased pine (Pinus sp) overstory cover and precipitation at home-range spatial scales, areas with low and high amounts of canopy cover and slope, and cooler August temperatures. Unlike other recent literature on the species, we found little evidence that Humboldt marten locations were associated with old growth structural indices, perhaps because of a potential mismatch in the association between this index and shrub cover. As with any species distribution model, there were gaps in predicted distribution where Humboldt martens have been located during more recent surveys, for instance the southeastern portion of Oregon’s coast range. Conservation efforts and our assessment of potential risks to Humboldt marten populations would benefit from additional information on range extent, population sizes, and fine-scale habitat use. Like many rare and lesser-known species, this case study provides an example of how limited information can provide differing interpretations, emphasizing the need for study-level replication in ecology.


2020 ◽  
Vol 29 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Hasan K. Saleh ◽  
Paula Folkeard ◽  
Ewan Macpherson ◽  
Susan Scollie

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.


2006 ◽  
Vol 175 (4S) ◽  
pp. 511-512
Author(s):  
David G. McLeod ◽  
Ira Klimberg ◽  
Donald Gleason ◽  
Gerald Chodak ◽  
Thomas Morris ◽  
...  

2006 ◽  
Vol 175 (4S) ◽  
pp. 46-47
Author(s):  
Daniel J. Lewinshtein ◽  
K.-H. Felix Chun ◽  
Alberto Briganti ◽  
Hendrik Isbarn ◽  
Eike Currlin ◽  
...  

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