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Arco Desert - Bingham County
(Bradfield 1975) studied a declining population of pygmy rabbits in the Arco Desert 30 km. northwest of Blackfoot. Bradfield’s study site was outside the INEEL boundary. Large numbers of pygmy rabbits were found killed during winter months (skulls were found), as were abandoned burrows. He believed the number of pygmy rabbits in the study area was decreasing. During the course of this work, he visited Ironsides in Malheur County Oregon and found only evidence of past pygmy rabbit occupation, but no pygmy rabbits or fresh sign. He concluded: “The population is declining not just on a local level but on a much larger geographic level”. Ironsides is the location of Anthony’s (1913) observations.
INEEL - Butte, Jefferson, Bingham Counties
The Idaho National Environmental and Engineering Laboratory (INEEL) is located in the northeastern Snake River Plain, and has been the site of several graduate studies on pygmy rabbits conducted from 1976 – 1980, and again in the mid to late 1990s. There has been no long-term census data collected, but as described below, populations have plummeted. Note: An extra “e” for Environmental has been added in recent years to enhance palatability of this nuclear facility.
In 1976, the pygmy rabbit was still an important component of the native fauna at INEL on the northern Snake River Plain. “On the parts of the Arco desert where the pygmy rabbit is found, it is often the only large mammal visible during the winter, as evidenced by tracks, and probably forms an important part of the prey base” (Wilde et al. 1976). Pygmy rabbit remains were found in avian predator nests, and coyotes regularly investigated burrows. ”It may be an animal whose range is decreasing, especially with the continued destruction of appropriate sage habitat for farming, grazing and human habitation”, and had been described by Hibbard (1963) as existing only in relict populations (Wilde et al. 1976).
Researchers at INEEL in the mid to late 1990s found a marked decline at sites where Wilde and Fisher had studied pygmy rabbits (Gabler 1997). Pygmy rabbit populations at INEEL appeared to be very low relative to past studies (Gabler 1997). Searches conducted in three areas of INEEL that had been studied by Wilde (1978) and Fisher (1979) produced few animals. Wilde (1978) estimated pygmy rabbit numbers ranging from 27 to 40 animals in one area, and 7 to 27 animals in a second area. Gabler (1997) relocated these areas – the first contained two collapsed pygmy rabbit burrows, and no other sign. The second area contained 4 active burrows, but these were all abandoned within 10 months of discovery. A third area had been used by Wilde, but he aborted field work at this site due to a decline in pygmy rabbit numbers. Gabler searched this area, and found 34 abandoned burrows. Gabler (1997) notes similar overall declines in evidence of pygmy rabbits have been observed in many other studies (Janson 1946, Bradfield 1975, Wilde 1978, Weiss and Verts 1984), plus the Washington state populations blinking out.
At INEEL, as an example of the progressive habitat loss and fragmentation associated with fire, 12% of the INEEL area predicted as rabbit habitat based on older GIS mapping had been destroyed by fires in 1994-1996. There have been large new fires since the 1994-1996 period. Gabler (1997) stressed that low range fire intervals (50 to 100 years) had historically allowed sagebrush to recover following fire, but with cheatgrass invasion, fire frequency has greatly increased, so fires are now a threat to pygmy rabbits.
Twelve of 17 INEEL sites with pygmy rabbit sign contained abandoned/inactive burrows. Only 4 of 17 predicted sites contained fresh pygmy rabbit scat. Of 101 burrows discovered during initial road surveys, only 26 burrows were active when they first were found (Gabler 1997).
A 1996 news release, “Small rabbit focus of big study at INEEL” by DOE’s ESER (Environmental Surveillance, Education and Research Program stated: “Areas of sagebrush habitat in the intermountain West have been shrinking and the quality of the remaining sagebrush habitat has decreased. At the same time the population of pygmy rabbits has drastically declined. This decrease is found even in protected areas like INEEL. With this decline, the pygmy rabbit is being considered for the threatened and endangered species list” (ESRF News Release, 12/30/96). A January 2003 ESER Newsletter states: “Pygmy rabbits have drastically declined in the past decade, even at protected areas like INEEL” (ESER 2003). www.stoller-eser.com/Newsletter/January2003.htm.
The level of protection, and habitat loss and fragmentation at INEEL, actually varies quite a bit. 60% of INEEL lands, including lands in the Sagebrush-Steppe Reserve, continue to be intensively grazed, disturbed and altered on an annual basis by domestic livestock. Recent large fires have consumed big sagebrush habitats. Plus, there are significant environmental intrusions – roading, facilities, powerlines, other infrastructure - that fragment remaining big sagebrush habitats. Radioactive contamination has also been documented in rabbits and other vertebrates in and around INEEL. See later INEEL discussion under Protected Areas. In addition, planning is underway for a massive new nuclear reactor at INEEL that will result in new habitat destruction (see Senator Larry Craig E-News 3/28/03, as well as likely new radioactive contamination of INEEL and surrounding lands. Past nuclear facilities at INEEL have resulted in extensive contamination problems (Morris 1993, Environmental Defense Institute March 2003).
Burley BLM lands – Twin Falls, Cassia, Oneida Counties
Over twenty years ago, a 1980 report on Burley BLM lands by Western Environment Research Associates stated: “This leporid appears to be unable to respond to changing environmental conditions especially destruction of tall dense stands of big sagebrush”. Current grazing and farming practices are rapidly reducing the habitat required by this species. Keller (unpub) cited in this report notes that in Idaho, the pygmy rabbit is found along washes and springs where sagebrush is dense. The report cites Fisher and Keller (in press) as suggesting: ”Current grazing and farming practices are rapidly reducing the habitat required by this species”. Dr. Barry Keller was a noted Idaho biologist.
Austin (2002) documents an escaped BLM “prescribed burn” causing abandonment of an active pygmy rabbit burrow system in Wilson Gulch in the Goose Creek watershed. Petitioners have long Protested any more burns or other vegetation manipulation in the already radically altered and fragmented BLM lands of the Burley Field Office. In a 2000 field trip to the site of this same burn with Upper Snake River District BLM Manager Jim May, Fite and others observed extensive zones of livestock degradation, and scorching of soils from the ill-conceived Prescribed burn project that went awry. Subsequent livestock trespass of this and other Burley BLM burns has been extensively documented (Austin and others), thus leading to even further degradation of remnant native vegetation and further limiting any recovery of native vegetation. Austin, in a series of detailed and extensive reports in 1999, 2000, 2001 and 2002 has reported on the appalling condition of riparian areas –streams, springs, seeps, and interfacing upland habitats in Burley Field Office lands.
A 2002 survey of Burley BLM lands found pygmy rabbits in only two locations in the entire Field Office (White and Bartels 2002). In this survey, screening of Burley lands for sites that still had big sagebrush cover was first conducted, and 11 allotments were identified as potential habitat. These were intensively surveyed. The study focused on Shoshone Basin, the Raft River Valley, and the South Hills. Only 35 burrows with signs of recent occupancy by pygmy rabbits were found in the entire area surveyed. Only 6 burrow systems on 2 allotments were identified as active. Three active burrows systems were found on the Mule Creek allotment, and three active burrows systems were found on the Horse Creek allotment. Sagebrush canopy cover of occupied burrows averaged 35%, and sagebrush height was 95 cm. A collapsed burrow was found in the Jim Sage allotment, an inactive burrow in the Dry Creek allotment, 15 inactive burrows in the Strevell allotment, and 11 burrows with 2 collapsed burrows in the Clear Creek allotment. The 11 allotments that were intensively searched contained only “sections of native vegetation”.
Both Burley allotments with occupied burrows touch the Nevada border east of Jackpot. The Horse Creek allotment touches lands in the notoriously livestock-degraded Elko BLM managed Salmon River allotment (see Elko BLM Salmon River FMUD, monitoring report), with which petitioners are very familiar. In the neighboring Salmon River allotment, large acreages have burned in recent fires. Plus Elko BLM’s final grazing decision here recently unleashed a plethora of pipeline developments and livestock fences in remaining big sagebrush uplands. This huge allotment is grazed by both cattle and sheep, and sheep grazing at times is so extreme that big sagebrush plants are being devoured and killed by domestic sheep (Fite and Tucci field observation 2001). This allotment has been repeatedly visited by Nevada State BLM Director Robert Abbey, due to its extremely degraded condition (Fite and Marvel participated in these field tours).
In addition to the intensive survey of remaining big sagebrush habitats, “31 separate historical pygmy rabbit locations in the Burley Field Office lands were also visited as part of the survey. 18 were vague locations and not properly located, 8 were found disturbed due to agricultural development, urban development, wildfire and seedings. Only 5 were potential habitat, but no occupied burrows were found” (White and Bartels 2002).
Many of the Idaho Conservation Data Center (CDC) records in this area, and several historical sites revisited by White and Bartels, were close to towns. Collectors of museum specimens and early observers appear to have centered their activity in areas or along major roads (Burley, Rupert vicinity), and ventured less into backcountry locales. So here, as throughout the species’ range, its true former presence and abundance in more remote locations is likely not reflected in historical records.
Severe and extreme livestock degradation has been observed in many areas of remaining big sagebrush habitats in Burley Field Office lands by Austin (series of riparian reports). Over 20 years ago, Dr. Barry Keller emphasized big sagebrush surrounding springs and seeps in Burley FO lands as important pygmy rabbit habitats (WSER 1980). Austin, in a series of riparian reports supplied to Burley FO, has provided exhaustive documentation of the current atrocious condition of springs and their big sagebrush surroundings throughout the Burley FO. Yet, White and Bartels (2002) underplay the role of livestock in alteration and destruction of pygmy rabbit habitats in BFO lands, stating that the role of livestock grazing is not well understood, and refer to the supposed benefits of livestock in increasing sagebrush cover, stating that pygmy rabbits evolved in the presence of ungulate grazing so and “the influence of cattle grazing on pygmy rabbit habitat is not well understood”, and refer to “overstocking” as a problem. This is reminiscent of the statements made by WDFW in the early to mid-1990s, as they justified continuing livestock grazing on small occupied pygmy rabbit habitats in Washington.
White and Bartels (2002) conclude that pygmy rabbits in Burley lands were historically affected severely by the removal of big sagebrush for agriculture, and that current pygmy rabbit low abundance and population is most likely due to recent wildfires and a slow habitat restoration process. This conclusion does not explain the absence of pygmy rabbits from nearly the entire 133,000 acres of the best remaining big sagebrush in BFO lands surveyed (where only 23,660 acres have burned), and its currently extremely low abundance at these two sites.
White and Bartels (2002) discuss the removal of sagebrush and fragmentation of habitat north and south of the Snake River. The Snake River had historically dried up in eastern Idaho. Thus, populations of pygmy rabbits north and south of the Snake River had historically been connected prior to dam construction which resulted in permanent water flow in a previously seasonally dry section.
White and Bartels (2002) conclude: “We believe the low population and abundance of pygmy rabbits that was found during this survey represents their status in the Burley FOA”.
A recent windshield survey by Roberts (2002) included the Burley Field Office and Curlew National Grasslands, with no sign of rabbits found in BFO lands, and observed that the BFO has produced the most pygmy rabbit records [over time] with records dating back to 1910. Roberts also stated: “This FOA has been severely fragmented by agriculture and wildfires. It is highly unlikely that any more than widely scattered rabbit activity will be found”.