Ideal conditions for increased trapping success of pygmy rabbits (Brachylagus idahoensis) across the Great Basin

2020 ◽  
Author(s):  
M M Crowell ◽  
K T Shoemaker ◽  
M D Matocq

Abstract Sagebrush-steppe ecosystems are one of the most imperiled ecosystems in North America and many of the species that rely on these habitats are of great conservation concern. Pygmy rabbits (Brachylagus idahoensis) are one of these species. They rely on sagebrush year-round for food and cover, and are understudied across their range in the intermountain west due in part to their recalcitrance to standard capture techniques. Identifying an efficient and minimally biased trapping method therefore is a critical first step in learning more about this species. We assessed how trap orientation and weather characteristics influenced trap success for Tomahawk traps placed in and around pygmy rabbit burrows by carrying out trapping surveys at 16 occupied pygmy rabbit sites across the Great Basin from 2016 to 2018. We found that pygmy rabbits had a greater probability of being captured in traps with the open end facing away from burrow entrances. Pygmy rabbits also were more likely to be captured on clear days (0–5% cloud cover) and during periods of cooler temperatures during summer months (June–August). We found no evidence that sex or age ratios differed, or that individuals differed meaningfully, in their preference for certain trap orientations. To increase trap success for pygmy rabbits, we suggest maximizing trapping effort during summer months, at dawn, and maximizing the proportion of Tomahawk traps facing away from burrow entrances. We anticipate that our monitoring protocol will enable more effective research into the ecology and conservation of this cryptic and potentially imperiled species.

2014 ◽  
Vol 5 (1) ◽  
pp. 118-123
Author(s):  
Wendy A. Estes-Zumpf ◽  
Shane E. Zumpf ◽  
Janet L. Rachlow ◽  
Jennifer R. Adams ◽  
Lisette P. Waits

Abstract The pygmy rabbit Brachylagus idahoensis is a sagebrush-obligate species of conservation concern that occurs in the Great Basin and adjacent intermountain areas in the western United States. The species is not known to occur in Colorado, despite proximity to existing populations of pygmy rabbits in Wyoming. We provide the first documentation of the pygmy rabbit in Colorado. Fecal pellets diagnostic of pygmy rabbits were collected in the Vermillion Bluffs area of northwestern Colorado. Samples from 16 pellet clusters were collected for species identification via genetic analyses, and we were able to extract and amplify sufficient DNA from 7 of 16 pellet samples. All seven samples were identified as originating from pygmy rabbits based on a species-specific mitochondrial DNA fragment analysis test. To verify species identification, we also sequenced 225 base pairs of the mitochondrial DNA cytochrome b region from all seven pellet samples. Presence of pygmy rabbits was confirmed from three locations separated by 2.4–7.7 km and pellets represented both adult and juvenile rabbits. Based on the sparseness of burrows in the area, density of pygmy rabbits in the area likely is low; however, systematic surveys by trained observers are needed to delineate the range and density of this species in Colorado. Given the conservation concern for pygmy rabbits across their current range, the newly confirmed presence of this species suggests that assessment of their conservation status in Colorado is warranted.


Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Cara Applestein ◽  
Matthew J. Germino

Abstract Background The need for basic information on spatial distribution and abundance of plant species for research and management in semiarid ecosystems is frequently unmet. This need is particularly acute in the large areas impacted by megafires in sagebrush steppe ecosystems, which require frequently updated information about increases in exotic annual invaders or recovery of desirable perennials. Remote sensing provides one avenue for obtaining this information. We considered how a vegetation model based on Landsat satellite imagery (30 m pixel resolution; annual images from 1985 to 2018) known as the National Land Cover Database (NLCD) “Back-in-Time” fractional component time-series, compared with field-based vegetation measurements. The comparisons focused on detection thresholds of post-fire emergence of fire-intolerant Artemisia L. species, primarily A. tridentata Nutt. (big sagebrush). Sagebrushes are scarce after fire and their paucity over vast burn areas creates challenges for detection by remote sensing. Measurements were made extensively across the Great Basin, USA, on eight burn scars encompassing ~500 000 ha with 80 plots sampled, and intensively on a single 113 000 ha burned area where we sampled 1454 plots. Results Estimates of sagebrush cover from the NLCD were, as a mean, 6.5% greater than field-based estimates, and variance around this mean was high. The contrast between sagebrush cover measurements in field data and NLCD data in burned landscapes was considerable given that maximum cover values of sagebrush were ~35% in the field. It took approximately four to six years after the fire for NLCD to detect consistent, reliable signs of sagebrush recovery, and sagebrush cover estimated by NLCD ranged from 3 to 13% (equating to 0 to 7% in field estimates) at these times. The stabilization of cover and presence four to six years after fire contrasted with previous field-based studies that observed fluctuations over longer time periods. Conclusions While results of this study indicated that further improvement of remote sensing applications would be necessary to assess initial sagebrush recovery patterns, they also showed that Landsat satellite imagery detects the influence of burns and that the NLCD data tend to show faster rates of recovery relative to field observations.


Author(s):  
Katherine Parker ◽  
Todd Katzner

Relatively little is known about pygmy rabbits Brachylagus idahoensis except that they are typically associated with dense stands of big sage Artemisia tridentata. Because they are entirely dependent on sagebrush communities for survival, however, they may potentially serve as an effective means of environmental surveillance in shrub-steppe grasslands. The overall objective of this study is to clarify some of the ecological/physiological adaptations of the world's smallest leporid and define its obligate shrub-steppe association relative to structural, compositional, and micrometeorological features. We placed particular emphasis on the winter ecology of pygmy rabbits, and on understanding how such a small species (400 grams) that does not hibernate or significantly deposit fat, manages to survive in areas of extreme environmental temperatures, consuming primarily sagebrush.


2010 ◽  
Vol 86 (2) ◽  
pp. 47-56 ◽  
Author(s):  
Carrie Caselton Lowe ◽  
Sara M. Birch ◽  
Stephen P. Cook ◽  
Frank Merickel

2012 ◽  
Vol 65 (4) ◽  
pp. 362-370 ◽  
Author(s):  
Robert P. Breckenridge ◽  
Maxine Dakins ◽  
Stephen Bunting ◽  
Jerry L. Harbour ◽  
Randy D. Lee

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