Local Government:    SKR

1995 Petition to Delist (Full Text) | Stephen's Kangaroo Rat 

2002 perkin's Petition to Delist 

February 22, 2002

Field Supervisor

U.S. Fish and Wildlife Service

2730 Loker Avenue West

Carlsbad, California 92008

Robert Eli Perkins, a private citizen residing in California, hereby petitions the United States Fish and Wildlife Service to delist the Stephens’ kangaroo rat (Dipodomys stephensi) under the Endangered Species Act of 1973 and its amendments.

The petitioner requests this delisting because of original data errors in the listing of 1988 and because habitat conservation measures by Riverside County Habitat Conservation Agency have acquired and preserved extensive amounts of habitat. Investigation by the Riverside County Farm Bureau has revealed a significant amount of scientific evidence that SKR is not now and never has been in any danger of extinction. This conclusion is further strengthened by the extensive habitat preservation efforts of the Riverside County Habitat Conservation Agency.  Assumptions by U.S. Fish and Wildlife Service regarding species range, habitat requirements, population size, population density, protected populations, reproductive ability, ability to persist in small patches, and colonization capability were all substantial underestimations. Assumptions by U.S. Fish and Wildlife Service regarding threats to SKR, including percentage of lost historical habitat, rate of loss of habitat, impacts from rural development and agriculture, and urban growth patterns, were all substantial exaggerations.

U.S. Fish and Wildlife Service incorrectly stated that many new data supporting listing became available after SKR was listed as a candidate species, when in fact the only data to become available was biological surveys for developments which actually indicated that SKR was more widespread and abundant than previously thought and that the habitat was safer from destruction than previously thought.

U.S. Fish and Wildlife Service relied on the flawed method of only returning to sites where SKR was historically found rather than analyzing the full range of habitat. This method disregarded the known dynamic characteristics of SKR habitat utilization, and a lack of any comprehensive search for new inhabited sites represents a failure to obtain the best scientific information available.

Acreage figures in the proposed rule are questionable based on an example of a major mathematical error. The proposed rule stated that small patches of SKR populations are about 40 acres in size or 100 hectares. One of these numbers is incorrect, in that 40 acres equals about 17 hectares and 100 hectares equals 247 acres. The author divided 100 hectares by the conversion factor of 2.47, rather than multiplying. It appears the author sought to minimize the actual size of small patches, substituting 40 acres for the more correct figure of 100 hectares or about 250 acres, thereby exaggerating the threat to the species. It has been proven by current knowledge that the SKR populations are in much, much larger contiguous patches, many are measured in the thousands of acres of contiguous occupied habitat. (RCHCA 10(a) EIR by RECON, Montgomery (Anza, 1992,) O’Farrell (Lake Henshaw, population known at time of listing), RB Riggan (Alessandro Heights survey, 1989.)

U.S. Fish and Wildlife Service misrepresented federal agency response when it stated in its summary of the final rule that federal agencies other than the Air Force indicated no opposition to the listing. In fact, the Air Force was the only federal agency to provide comment on the listing, filing a statement of opposition (see comments, included.) U.S. Fish and Wildlife Service offered a patently misleading statement in characterizing non-response by other federal agencies as “no opposition. 

U.S. Fish and Wildlife Service misrepresented all other comments as “neutral,” when in fact comments by the Vista Irrigation District, included herein, could hardly be called neutral, the U.S. Fish and Wildlife Service count breakdown does not make any sense, and other supporting comments aren’t itemized in the final rule.  

U.S. Fish and Wildlife Service failed to acknowledge the true situation with regard to the California Department of Fish and Game and the California Endangered Species Act. While CDFG submitted comments supporting the SKR listing, U.S. Fish and Wildlife Service failed to note or consider the significant fact that CDFG had failed to persuade its own California Fish and Game Commission that SKR was endangered and required upgrading from its state “threatened” status. The Federal Record indicated CDFG provided a copy of a recent status update, yet U.S. Fish and Wildlife Service failed to mention that it got almost all of its SKR information for the listing forwarded to it from just one CDFG employee after the California Fish and Game Commission voted not to upgrade the species to endangered.

U.S. Fish and Wildlife Service clearly disregarded the importance of definitively delineating the range of the SKR and relied on inadequate and incomplete research. U.S. Fish and Wildlife Service limited consideration to a specific area within the political jurisdiction of Riverside County while disregarding San Diego County and failing to discover SKR in Anza, Aguanga, Oceanside, and the Corona-Norco area. Inadequacy of U.S. Fish and Wildlife Service research information is underscored by expansion of known occupied SKR habitat and population in Riverside County study areas, in Temecula, in Ranchita, (as per Dick Friesen personal communication, 1/93.) U.S. Fish and Wildlife Service based its listing decision on inadequate information about SKR habitat and populations outside its historic range and lack of knowledge of existence of SKR on public and private property. U.S. Fish and Wildlife Service relied on flawed and inadequate methods for locating SKR outside of historic range, discovering the extent and abundance of SKR only after a development land use activity is planned that requires biological surveys.

U.S. Fish and Wildlife Service selectively used scientific information to support its listing decision and to suppress facts which would have raised doubts about the need to list SKR as endangered. Price and Endo 1988 was cited without reference to the positive aspects of this study, which revealed SKR population could increase tenfold in just one year of high rainfall.

U.S. Fish and Wildlife Service again overstated the threat to SKR as occurring rangewide, when this is clearly not the case, and disregarded the large amounts of protected SKR habitat on public lands which were and are safe.  

U.S. Fish and Wildlife Service inaccurately contended that lands held in public ownership were not sufficient to ensure survival of SKR, when in fact U.S. Fish and Wildlife Service had failed to correctly assess the extent of occupied and potential habitat protected on public lands.

U.S. Fish and Wildlife Service grossly underestimated the viability of SKR populations on public lands and greatly overestimated the threat to SKR on those lands by implying that SKR habitat needs close monitoring and active management. They further implied that because most of the federal agencies using the land had no such active management plan, SKR was therefore imperiled. However, this implication ignored the fact that the land use activity and disturbances characteristic of the mission of the particular federal agencies are likely the very reason SKR is present.

U.S. Fish and Wildlife Service admitted that the activities of the agencies with occupied SKR habitat are compatible with the species, yet this was never stated in the proposed rule. It is further evidence that the species is more abundant and less threatened than U.S. Fish and Wildlife Service indicated in its proposed rule.

The system of permanent preserves that has been subsequently proposed by Riverside County Habitat Conservation Agency mainly comprises public lands which were already conserved at the time of the listing. RECON, the consultant to RCHCA which has developed much more extensive information about SKR, concluded that public lands are more than enough to sustain the species. Predictions of SKR survival have been based in part on a computer model, the Gilpin Model, which fails to take into account “smart dispersion,” the ability of SKR to migrate to suitable new habitat, to survive and expand in a habitat environment that historically is in a constant state of change. Both U.S. Fish and Wildlife Service projections and the Gilpin Model are overly pessimistic and contribute to the underestimation of SKR populations and survival and the overstatement of the threat to SKR.

U.S. Fish and Wildlife Service dismissed the issue of compatible land uses because it failed to obtain complete and accurate information about SKR habitat requirements and in fact discarded information about the positive aspects of compatible land uses that was available in the same reports which U.S. Fish and Wildlife Service used in its proposed rule. U.S. Fish and Wildlife Service failed to recognize that land disturbances associated with compatible land uses caused increases in SKR populations. This is demonstrated by the decline in suitable habitat by coastal sage scrub encroachment as a direct result of U.S. Fish and Wildlife Service restrictions on farming, firebreak clearing and other activities.

U.S. Fish and Wildlife Service falsely stated that it had determined from careful review that SKR should be listed as “endangered,” when in fact the decision was an arbitrary determination arrived at in a telephone conversation between Karla Kramer, author of the proposed rule, and Ron Novak of the U.S. Fish and Wildlife Service Office of Endangered Species in Washington in which the two individuals discussed whether to propose SKR for listing as “threatened” or “endangered” (phonecon notes, included.)

The U.S. Fish and Wildlife Service statement that SKR habitat and range had been greatly reduced is inherently false, because U.S. Fish and Wildlife Service demonstrably lacked complete and available information about the historic range of the SKR and about the current range of the SKR. U.S. Fish and Wildlife Service lacked range information necessary to make comparisons to reach a conclusion that range had been reduced and also failed to investigate reports of habitat (i.e., the Orange County coastline,) “rounded off” occurrences on maps and otherwise disregarded available information which indicated the SKR was more widespread and not under threat.

The range of the SKR was not known at the time of the listing, and it is still not precisely determined. This is amply demonstrated by: discovery of SKR at numerous locations not included within the “historic range” and the corresponding mitigation fee area in Riverside County designated by Riverside County Habitat Conservation Agency, such locations as Anza, Potrero, Diamond Valley, Sage, Tucalota Valley and the Corona-Norco area; requirements for SKR biological surveys at locations outside the previously assumed range, such as at Ontario International Airport in Ontario; local government concerns about getting permits to take SKR outside the previously assumed range, such as Beaumont; and, the plainly observable access to extensive areas of potential habitat adjacent to known SKR populations, such as north and west from Riverside County into San Bernardino County, east into the Banning Pass, and southeast toward Anza-Borrego National Park.

The proposed rule inaccurately described the Stephens’ kangaroo rat, in part, as having an ear measurement averaging 15mm. After the listing was finalized, the SKR working group of biologists published a document through U.S. Fish and Wildlife Service intended to aid in differentiation of SKR from PKR, that stated SKR had an ear crown of 13mm or less, and the PKR had measurements of 13mm or greater. A letter dated November 7, 1989, from the field supervisor of the Carlsbad office of the U.S. Fish and Wildlife Service, to an SKR permitee, stated that SKR has a typical ear-crown measurement of less than 12mm, and PKR generally have a measurement of 13mm or greater.

The range was described as being limited to the Perris, San Jacinto Valleys of Riverside County, and the San Luis Rey and Temecula Valleys of San Diego County. (Note that the Temecula Valley was incorrectly described as being in San Diego County.) Subsequent discoveries of the species, both before and after the proposed rule was published, reveal this statement to be not only inaccurate, but also misleading. The proposed rule contradicted this statement later in the text of the rule. At the time the proposed rule was published, the SKR was also known to be present in the Riverside, Lake Mathews, Estelle Mountain, and Sycamore Canyon areas, as well as the Moreno Valley, Canyon Lake, and Lake Skinner areas. U.S. Fish and Wildlife Service was also aware of SKR localities ranging as far north as the Cajon Pass area in San Bernardino County, to Bautista Canyon east of Hemet, in the east, and south to Oceanside. A very large, well-established population that occurs far to the southeast on the Warner Ranch around Lake Henshaw was ignored in the proposed rule, (O’Farrell, 1986.)

Populations of SKR, including those at Anza, Potrero, Aguanga, Tucalota Valley and the Corona-Norco area, have been discovered: in areas previously thought unoccupied within the presumed historical range; outside the presumed historical range; and, in well-established populations in areas that are not only far outside the presumed historical range but also in areas and at elevations thought to be uninhabitable for the species, (Montgomery, 1992.)

The proposed rule stated a habitat association of SKR with Artemisia californica and Erigonium fasciculatum, two brushy plant species characteristic of coastal sage scrub habitats. However, the SKR working group later stated, when discussing habitat of the SKR, “there is a strong correlation between the proportion of annual forbs to annual grasses with the probability of presence or absence of the Stephens’ kangaroo rat and the densities found.” While this statement is more accurate than the rule, discussing the habitat preference of the species, it is not complete. Current information indicates SKR inhabits a wide variety of vegetation types; native and non-native grasslands, sandy washes and drainages, agricultural fields, disturbed chaparral, dirt roads, and coastal sage scrub.

U.S. Fish and Wildlife Service failed to adhere to the Endangered Species Act because it has failed to initiate a recovery plan for the SKR.

Species range

The described range in the proposed rule was incorrect and incomplete. The known range of the Stephens’ kangaroo rat was described as being limited to the Perris and San Jacinto Valleys, and San Luis Rey and Temecula Valleys. This range description cites only four researchers as sources, when many more sources were available to U.S. Fish and Wildlife Service at the time.

A study dated 3 June 1983 by an unknown author, included in the administrative record, helped to create many false impressions and perpetuate factual errors concerning SKR. Two key aspects of this study point to the fallacious logic used to create the argument that the species required Endangered Species Act protection.

The study cited the work previously done on SKR by researchers who attempted to perform “range-wide” status reviews of the species. However, those researchers’ studies were often merely re-investigations of historical locations where SKR were found, and seriously lacked in any new investigation or attempts at locating new SKR sites. Therefore, when a particular researcher looked for SKR at a site known to harbor SKR some 20, 30, or 60 years before, and the site had been developed, or for some other unknown reason the species was absent from the site at the time, it was assumed that the species would soon be extirpated from all of its known sites, (Thomas, 1975.) The argument was then made that the species was threatened and later the argument was given greater urgency by saying the species was in imminent danger of extinction, due to the county’s growth.

This type of flawed thinking is exemplified in this statement from the introduction to the study: “SKR was the topic of three master’s theses in 1973 that involved review of Grinnell’s sites (Thomas 1975) and investigation of range limits of rodents (Bleich 1973 & 1974, Bontrager 1973).” Though the introduction does state that, “the Bleich study resulted in the publication of a major range extension for the species (Bleich & Schwartz 1974),” the report does not specify where this discovery was located.

The known range of the Stephens’ kangaroo rat has greatly expanded since the publishing of the proposed rule. Information now shows that SKR is endemic to the foothills of the Lake Mathews area, Estelle Mountain, the areas around Lake Skinner and Bachelor Mountain, the foothill areas between Lake Elsinore and the Perris Valley, the Norco Hills and parts of the City of Corona, the Anza Valley, Lake Henshaw and Warner Springs areas of northern San Diego County, and the military bases of Camp Pendleton and the Fallbrook Naval Weapons Station. Recent surveys have shown substantial populations of SKR in the Tucalota Valley, Sage area, and Diamond Valley. These latter discoveries were part of a Section 7 consultation and biological surveys for prescribed burning activity by the California Department of Forestry and Fire Protection.

SKR populations at Camp Pendleton were cited in the final rule without any explanation as to why they were omitted in the proposed rule. Omission of these significant SKR populations on federal lands indicates SKR is more widespread and abundant and the threat to SKR is less than originally stated.

The statement in the final rule that “Vista Irrigation District, MWD, and State of California have large blocks of suitable habitat” was not included in the proposed rule. Omission of these significant masses of protected habitat is another indication that the habitat range and abundance of SKR were understated and the threat to SKR was overstated. The inclusion of new information in the final rule, indicating less threat to SKR, should have caused a reexamination of the need to list.  

The Anza Valley discovery is an interesting case for discussion. In 1992 SJM Biological Consultants was commissioned to perform a trapping survey of an approximately 800-acre site of a proposed country club on the Cahuilla Indian Reservation in the Anza Valley. This survey found SKR inhabits at least 400 acres of the site. Montgomery stated, “No attempt was made to determine the distribution of the species throughout the property.” (Montgomery 22 February 92.) However, he also stated in the report, “Although all suitable habitats on the site were not searched for kangaroo rat sign, it is very likely that most or all extant grasslands are occupied by Stephens’ kangaroo rats.” He estimated 400 acres of grasslands on the site.

Montgomery went on to state in his report that he believed the Anza Valley harbors a large population of SKR. “These results verify that a sizable population of SKR exists in the Anza region, which suggests further that this species occurs elsewhere in this broad valley.” (Montgomery ibid.)

This assumption was confirmed by Montgomery and U.S. Fish and Wildlife Service personnel through subsequent investigation. At the request of U.S. Fish and Wildlife Service, the developer of the country club retained Montgomery to perform a helicopter survey of the entire 70,000-acre valley. Montgomery found suitable habitat and/or evidence of SKR in several locations throughout the valley. Widespread occupation by the species was also confirmed through trapping by Montgomery. According to a map of the area given to the developer by Montgomery after the survey, SKR was confirmed through trapping at areas as widespread as the source of Coyote Canyon in the southeast portion of the valley, to near the Ramona Indian Reservation in the north, and other large areas on the Cahuilla Reservation in the central portion of the valley. The map has written in the margin (presumably by Montgomery,) “Potential SKR habitat is abundant in the area.” In all, Montgomery’s map (Montgomery, April 92) showed SKR (confirmed through live trapping,) SKR habitat, or suitable SKR habitat fragments on all or parts of 38 sections of land throughout the Anza Valley. This habitat is on Indian lands and private range lands, near checkerboard BLM ownerships and the San Bernardino National Forest.

The subsequent investigation by U.S. Fish and Wildlife Service personnel was part and parcel of a Freedom of Information Act request by the petitioner. The petitioner was verbally told that U.S. Fish and Wildlife Service had surveyed the area, and that “it didn’t appear there was that much really out there.” (U.S. Fish and Wildlife Service biologist John Bradley personal communication.) U.S. Fish and Wildlife Service biologist John Bradley indicated the survey consisted solely of driving and walkovers of the flat river valley only on the Cahuilla Reservation. Notes and diagrams of this survey were requested in petitioner’s Freedom of Information Act request, but the petitioner was told they did not exist. When the petitioner was able to view the SKR file in the U.S. Fish and Wildlife Service Carlsbad office, there were notes of a private meeting on the Anza Valley discovery between U.S. Fish and Wildlife Service, BLM, Bureau of Indian Affairs, the Riverside County Habitat Conservation Agency, and SKR scientific collection permit holders (including Montgomery.) These notes were requested to be included in the materials to be forwarded to the petitioner, but they were never provided to the petitioner by U.S. Fish and Wildlife Service.  

The species was discovered in 1990 in another location in Riverside County, northwest of the previously defined range. Before the discovery of SKR in the Corona and Norco areas, it had not been found north of Highway 91 (Montgomery 29 September 90.) In this study, Montgomery found SKR inhabiting 196 acres of a 235-acre parcel. The researcher captured 33 SKR and 14 Pacific kangaroo rats (a non-listed species) at the site, in habitat described as “dense grassland or dense scrub vegetation, on most extremely steep slopes....” Montgomery estimated one hillside where SKR were captured at 60% slope. This finding is contrary to the proposed rule’s statements that SKR only inhabits nearly level to moderate slopes.

The proposed rule erroneously cited the habitat as limited to level or low rolling terrain, but both Montgomery and O’Farrell found SKR on slopes up to 100%.

The statement in the proposed rule that SKR is confined to low rolling hills and level ridge tops is refuted by current facts of occupation.

Montgomery also speculated in the same study that SKR may exist in the additional undeveloped and relatively undisturbed lands to the north and possibly, the west of this new discovery in Norco. 

There is further indication that SKR inhabits large areas around Norco. In 1992 U.S. Fish and Wildlife Service biologist John Bradley indicated at an Advisory Committee Meeting of the RCHCA that, “Perhaps the Norco Hills should be added as an additional reserve study area.”  

Overall, an updated range map does not give a complete picture of the tremendous change in the amount of assumed suitable habitat and also the amount of actual occupied habitat. A more complete picture would show that U.S. Fish and Wildlife Service apparently assumed in 1987 that the habitat suitable for the species was limited to the valley floors of the San Jacinto, Perris, Temecula, and San Luis Rey Valleys and not the entire area contained within the shaded area of the range map. An accurate, updated range and occupation/habitat map would include those new areas outlined above, plus areas that were contained in the original map but assumed unsuitable. This is evident in the large amount of known occupied habitat in areas that were previously “holes” of thought-to-be unsuitable habitat in the map.

In all, SKR is now known to occur in an area much larger than the 717,000 acres stated in the proposed rule. The figure of 717,000 acres was considered by U.S. Fish and Wildlife Service at that time to have been the maximum range historically covered by the species, even before the arrival of European man.

Habitat requirements

Habitat of the Stephens’ kangaroo rat was incorrectly identified in the proposed rule as limited to “level or low rolling terrain. It is not found on extremely hard or sandy soils.”

We now know that SKR inhabits annual grasslands, sandy washes, coastal sage scrub to 50% cover, agricultural fields, and a wide variety of soil types including alkaline soils (Montgomery 1989.)

The proposed rule disproved its own assumption that SKR do not occupy sandy soils when it stated SKR may be found in “adjoining sandy washes of Southern California.”

The proposed rule cited Army Corps of Engineers activities in flood channels “where the species has been found” as a threat to SKR, conflicting with the other statement that SKR does not inhabit sandy soils. Sandy soils such as flood control channels were not included in the list of habitats available to SKR.

There are numerous surveys, by several biologists, that have shown SKR occupation in such varied habitats as washes and drainages, sandy soils, in alkali soils, and other types of soils.

Montgomery, in 1990 in Temecula, O’Farrell, Friesen, and other researchers have found SKR persisting in both hard and sandy soils.

The proposed rule stated that gravel was a common component necessary to habitat, but findings of SKR in a range of soils and habitat conditions disprove this.

The habitat requirements for SKR are much more varied than the proposed rule made them appear. In a report dated April 2, 1992, Dr. Michael O’Farrell described an area of SKR occupation that indicates the species’ ability to withstand significant impacts from urbanization, agriculture and isolation.

In describing the site O’Farrell wrote:

“The ca. 104 acre tract is bordered on the north by citrus orchard, on the west by Mockingbird Canyon Road and housing, on the south by Harley John Road and housing, and on the east by Washington Street and housing and was surveyed for occurrence of SKR in April 1989.”

Apparently the occupation of the site was relatively unchanged from the earlier study, as O’Farrell indicated in the report summary where he wrote: “Sign of SKR was found over the majority of the site similar to that found in the original survey. 

O’Farrell also indicated the site had been heavily impacted by off-road vehicle activity, something which was cited in the proposed rule as a factor threatening the SKR. “Although posted, the site is impacted by off-road vehicle activity which is particularly concentrated in the eastern portion of the site.” This does not appear to have had negative affects on SKR because O’Farrell later wrote that, “Sign of SKR was found over most of the project site....”

Another O’Farrell study dated 16 July 1989, showed the presence of SKR at a site nearly surrounded by either housing or other thought-to-be-unsuitable habitat and land uses. O’Farrell described the site as follows: “The tract site is bordered on the north by current housing construction and El Nido and El Mineral Roads, by citrus orchards on the east and west, and steep relatively undisturbed hillsides to the south. The entire area is crossed by a network of dirt roads, including the northern extension of Bull Canyon Road directly through the middle of the property. Scattered rural housing is present throughout adjacent lands.”

O’Farrell found SKR occupied areas along and adjacent to dirt roads on and adjacent to the site. Further, O’Farrell reported, “A large flat ridge in the western half of the site has been burned in the past. This area is currently occupied in high abundance by SKR. The only thing limiting a more widespread distribution on the site is the current presence of dense shrubs on most of the property.”

This passage suggests SKR is able to utilize a variety of habitats in an opportunistic manner, either after disturbances or manipulation by mechanical, animal or fire changes. The evidence supporting this is apparent from the surrounding land uses that are thought to be unsuitable for the species. These include the citrus groves, the steep hillsides, and housing. This report and others also indicate the ability for SKR to disperse and colonize new areas through the use of man-made roads and trails. This characteristic of SKR is found repeatedly in reports by various researchers.

The ability for SKR to inhabit and colonize both grazed lands and farmed fields has not only been demonstrated through the increased research attention focused on the species since the federal listing, but was even known at the time of the listing. There is also evidence that U.S. Fish and Wildlife Service personnel working on the listing package knew of the positive effects of grazing on SKR habitat and the ability for SKR to persist in and around agricultural fields, yet the rules proposing and listing the species ignored this data and even implicated grazing as a factor causing its endangerment. This assumption overlooks the U.S. Fish and Wildlife Service surmise that prehistoric herds of deer and antelope (ungulates) provided habitat for SKR as they grazed in the presumed historic range.

A comprehensive study by RECON for the Riverside County Habitat Conservation Agency, published in 1991, focused on the subject of buffer areas for preserves for SKR. In the study, RECON examined five sites for the presence of SKR, all of which had development in close enough proximity to expect impacts on the species.

The researchers attempted to measure the necessary distance to avoid impacts to SKR by measuring the average distance between development and the occupied habitat. The result was that SKR was found an average of 27.3 meters or 89.6 feet from rural residential housing (defined as lots of one-half acre or more in size).

In 1982 Montgomery found that SKR can persist “next to human development indefinitely if the ground remains undisturbed.” This statement was in a study, portions of which were used in the proposed rule; yet, this favorable statement to the ability to coexist with development was omitted from the proposed.

In several other surveys, Dr. O’Farrell indicated evidence of the species’ ability to persist in small, fragmented habitat patches of linear shape for a period of years. The survey, (O’Farrell 1992, for S.I.C. Corporation) found 17.8 acres of occupied habitat in a linear fashion, bordering a graded housing tract. The site had been surveyed by O’Farrell in 1989 with similar results of occupied acreage, providing evidence of the species’ persistence over a period of three years. The survey is evidence of the apparent adaptability of SKR of successfully persisting, even colonizing, small linear patches of habitat. O’Farrell and other researchers performed additional work providing further evidence of this characteristic.

SKR has been found to exist in coastal sage scrub with densities approaching 50% aerial cover. This statement was made in a U.S. Fish and Wildlife Service letter to the U.S. Forest Service regarding the possible presence of the species on National Forest lands. The statement is qualified by explaining that occurrence in coastal sage scrub of high densities is usually when there is a large component of Encelia, or brittlebush, in the habitat. Due to Encelia being deciduous, U.S. Fish and Wildlife Service theorized that the habitat is essentially more open most of the year. This was supported by observation of Montgomery at a site near Riverside in 1990.

Numerous studies indicate SKR is able to successfully inhabit coastal sage scrub of various densities. Montgomery found SKR “to be resident in all open grasslands as well as sage scrub stands ranging from sparse to (in several areas) moderately dense.” Subsequent surveys by this biologist found SKR to be present in coastal sage scrub habitat that was “moderately dense”. He also observed SKR to inhabit pockets of “denser” sage scrub when it was near open areas or composed largely of Encelia.

Researchers often prematurely dismissed the possibility of SKR presence in various densities of coastal sage scrub even when kangaroo rat sign and burrows were observed. This practice often occurred when SKR presence was documented in open habitats directly adjacent to the coastal sage scrub habitat. Many biologists dismissed the presence of SKR in coastal sage scrub without a confirming trapping effort to positively determine the species of kangaroo rat present. These circumstances have unquestionably led to cases of misidentification of SKR presence as the presence of the non-listed Pacific kangaroo rat when habitat types overlap. An underestimation of the amount of available habitat, and the amount of SKR occupied habitat has occurred throughout the species range.

Population size

U.S. Fish and Wildlife Service obscured and misrepresented the size of habitat needed for a viable population of SKR. According to estimates at the time of the listing proposal, “low” abundance of SKR was less than five individuals per hectare (O’Farrell phonecon notes w/U.S. Fish and Wildlife Service, 1/28/86.)

The minimum viable population size stated in the final rule would mean that a small patch of 100 hectares occupied in “low” abundance would be characterized as viable. U.S. Fish and Wildlife Service then made a huge extrapolation, not cited as based on any biological information, that, because SKR doesn’t use all of its suitable habitat, it would take several square miles to support a more viable population. U.S. Fish and Wildlife Service did not indicate whether it is referring to occupied habitat or suitable habitat. This assumption was purely speculation unsupported by any scientific information.

U.S. Fish and Wildlife Service falsely presented a summary of comments received that failed to report information which had been provided to U.S. Fish and Wildlife Service indicating that SKR was much more widespread and therefore less threatened than U.S. Fish and Wildlife Service indicated. Petitioner found many examples in materials received from U.S. Fish and Wildlife Service under a Freedom of Information Act request showing that U.S. Fish and Wildlife Service had received information about how widespread SKR is but U.S. Fish and Wildlife Service failed to include this information in its summary.

Population density

The proposed rule cited densities of 20 to 50 SKR per hectare (which would be 8 to 20 SKR per acre,) when studies at Alessandro Heights (RB Riggan, 1989) near the City of Riverside showed densities of over 80 SKR per acre (which would be 198 SKR per hectare.) Thus, densities cited in the proposed rule are about one-tenth of actual known population densities. U.S. Fish and Wildlife Service underestimated SKR population densities by ten-to-one. 

The proposed rule stated that “most of occupied range probably has low to moderate density populations.” However, this assumption is entirely unsupported and disregards the high densities found in numerous locations, during and following years of normal to high rainfall.

Population densities can fluctuate greatly from year to year depending on amount and timing of rainfall. Research by Mary Price in 1984 on the Motte Reserve showed a tenfold increase in populations of Pacific kangaroo rats (D. agilis) in one year with high rainfall.

Protected populations

In proposing the species for listing, U.S. Fish and Wildlife Service completely ignored SKR populations protected on federal lands at Camp Pendleton and failed to document the number of occupied acres there.

Not only did U.S. Fish and Wildlife Service disregard SKR populations in numerous areas mentioned above, U.S. Fish and Wildlife Service failed to acknowledge protections that were in place in these areas, where habitat is secure from development

Lake Mathews has been a protected ecological preserve since before the SKR listing, and U.S. Fish and Wildlife Service failed to investigate SKR populations at this Metropolitan Water District land prior to listing. U.S. Fish and Wildlife Service claimed that agricultural and urban development around Lake Mathews and Estelle Mountain caused loss of SKR habitat but failed to document how much habitat was lost, how much remains and how agricultural activity may have benefited SKR.

Lake Mathews is now an SKR reserve study area and is proposed as a permanent core preserve.

U.S. Fish and Wildlife Service was entirely incorrect in its statement that March Air Force Base and Moreno Valley no longer support viable populations. There have been new populations discovered, more than 1,000 acres shown to be occupied and a reserve study area designation on March Air Force Base. Moreno Valley also supports SKR populations, as numerous biological surveys have indicated.

The U.S. Fish and Wildlife Service statement that federal lands form only a small part of the range of the species disregarded the extent of SKR populations on military reservations and the various environmental protection policies of the military services, specifically the Marine Corps at Camp Pendleton, the Navy at Fallbrook Naval Weapons Station, the Air Force at March Air Force Base. Protective policies extend even to nonlisted species, such as the burrowing owl at March Air Force Base. The statement also disregarded the significance of BLM lands (Montgomery 1989.) While discounting the importance of federal lands, U.S. Fish and Wildlife Service also disregarded other non-federal public agency lands such as the State Recreation Area at Lake Perris, the San Jacinto Wildlife Area, Metropolitan Water District land holdings, Vista Irrigation District lands, and lands held by the City of Riverside Parks Department.

U.S. Fish and Wildlife Service was equally incorrect in its statement that the area from Lake Skinner to Temecula has no viable population. Occupied habitat was documented throughout the area, Lake Skinner was designated a reserve study area and enjoyed protection from development, Temecula required more allocation of take under the RCHCA 10(a) permit because of additional population discoveries, and Shipley Ranch is heavily occupied and protected.

The U.S. Fish and Wildlife Service statement in the proposed rule that SKR was not recorded at Lake Perris since 1973 simply underscored the inadequacy of pre-listing surveys which did not look for SKR at Lake Perris or many other locations subsequently found to be occupied. SKR occupied state park lands at Lake Perris and habitat in the nearby San Jacinto Wildlife Area, both protected areas.

U.S. Fish and Wildlife Service overstated the threat to SKR populations around Lake Elsinore, disregarding the protections provided by BLM parcels. The area is characterized by off-road vehicle use, which O’Farrell, Price (1991) and other researchers have shown to be beneficial in disturbing the soil and providing dirt trails to encourage population movement within the habitat.

U.S. Fish and Wildlife Service incorrectly stated that the California Fish and Game Commission listed SKR as “endangered,” when in fact the commission voted not to list the species as endangered and indicated that the California Department of Fish and Game did not present enough information to warrant listing SKR as endangered. California had listed SKR as “rare” in 1971, and by virtue of the California Endangered Species Act of 1986, rare designated species were automatically classified as “threatened” with very little new information and no evaluation of the accuracy of information used to support the earlier “rare” designation. SKR remains listed as “threatened” in California.

U.S. Fish and Wildlife Service stated that California Department of Fish and Game consultations under the California Endangered Species Act are inadequate to protect SKR because they result in preservation of lands in another area while allowing “take” of SKR. U.S. Fish and Wildlife Service indicated this is an unacceptable situation for preservation of SKR. However, the Section 10(a) permit of the Riverside County Habitat Conservation Agency results in the same situation, where land is preserved in another location while allowing “take” of SKR.

Reproductive ability

The proposed rule inferred, from statements that pregnant female SKR were found in Spring, that reproduction is restricted to Spring. However, Price (post mortem and 1991 report on reproductive rates after rains,) O’Farrell, and others found that SKR are capable of producing litters year round.

The reproductive ability of SKR was underestimated. The rules published for the species indicated that the species was thought to only reproduce twice each year. Subsequent studies have indicated that the species will reproduce year round and have documented up to five litters per year. The same studies showed information suggesting the frequency and the size of the litters increased with the amount of rainfall in a given year, and with rainfall that occurred later in the year. A necropsy by Dr. Patrick A. Kelley (May 2, 1991) found a female, which died in the course of the trapping, pregnant with five fetuses.

Colonization capability

Populations of SKR were erroneously considered isolated, but there was no basis for assuming this.

In stating that SKR does not occupy all suitable habitat, U.S. Fish and Wildlife Service discounted the fluid characteristics of SKR populations, the fact that SKR populations can recover very quickly, and SKR’s persistence in recolonizing previously unoccupied habitat.

A 1984 study by University of California, Riverside, graduate student Narca A. Moore-Craig found SKR recolonizing a field within eight months after agricultural cultivation had ceased.

The Domenigoni family was restricted from using an 800-acre fallow field when SKR occupied it within one or two years (depending on the specific area in the field) after agricultural cultivation had ceased.

The Domenigoni family was also restricted in their cultivation activity on another, leased field. Even though a grain crop had been harvested from the field just five months earlier, SKR were present.

There are numerous other studies showing the colonization capability of SKR in disturbed areas.

Historical habitat

The proposed rule assumed that the historic range of the SKR was 717,000 acres, but this figure was just a guess and excludes “mountain tops,” which are not defined. This statement does not allow valid comparisons between historical and present population of SKR because U.S. Fish and Wildlife Service apparently did not exclude non-level terrain from its historical estimate, and then later, when calculating the amount of habitat remaining, U.S. Fish and Wildlife Service did exclude non-level terrain. U.S. Fish and Wildlife Service failed to explain what parameters it used to come up with its figures and failed to apply consistent parameters.  

By limiting the soil types identified as suitable for SKR during mapping of suitable soil types, U.S. Fish and Wildlife Service inaccurately extrapolated a historical habitat that was too restrictive, incorrectly illustrating the historical habitat as smaller than it actually is. Numerous examples show that SKR inhabits many more soil types than Price indicated in her soil type study, which was cited in the final rule.

The statement that 95% of original SKR habitat is gone was incorrect and based on incompatible assumptions for historic and present range. The large number was used as historic habitat in order to artificially raise the percentage of habitat gone, which, combined with discounting of present habitat which was incorrectly assumed unsuitable, resulted in overstatement of the threat to the survival of the species. There is no supporting information given to explain or define the “visual” inspection of this former range, if it was by aerial photos, walkovers, or Agricultural Stabilization and Conservation Service or other maps.

Human development and agricultural uses were already present in the early part of this century when the first studies of SKR were done. Dry-land grain farming and grazing were widespread on the valley floors since at least the late 1800s. U.S. Fish and Wildlife Service has failed to reconcile opposing assumptions, that agricultural activities which reduce invasive brush are also offensive to SKR but that SKR are displaced by invasive brush. U.S. Fish and Wildlife Service arguments that SKR thrive in open grassland suggests that grazing and agricultural practices introduced by European man enhanced SKR habitat. There is inadequate evidence that great herds of deer and antelope roamed the region’s valleys and curtailed brush invasion, as the proposed rule surmised. U.S. Fish and Wildlife Service wants it both ways, that brush is harmful but agricultural activities which remove brush and create habitat are also harmful, ignoring SKR’s ability to utilize a wide range of habitats.

U.S. Fish and Wildlife Service referred only to eight general areas where SKR is concentrated, which are (1) March Air Force Base to Moreno Valley, (2) Lake Perris to eastern San Jacinto Valley, (3) Lake Mathews to Estelle Mountain, (4) Lakeview Mountains, (5) Lake Elsinore, (6) Lake Skinner to Temecula, (7) Fallbrook Naval Weapons Station to San Luis Rey River, and (8) Lake Henshaw. This list overlooks other areas where SKR are found, including Corona-Norco, Temescal Canyon, Sycamore Canyon, Alessandro Heights, Potrero Canyon, Steele Peak, Camp Pendleton, Oceanside, Aguanga, Bautista Canyon, Hemet, Murrieta, Winchester, Menifee, and Anza Valley.

The U.S. Fish and Wildlife Service statement that only three of the referenced areas contain substantial amounts of habitat is proven grossly inaccurate by current information, with SKR populations found in abundance in numerous additional areas previously ignored by U.S. Fish and Wildlife Service.

The U.S. Fish and Wildlife Service statement that Lake Henshaw had 12,600 acres of suitable habitat omits the fact that more than 10,000 acres, or nearly all of the acres, is actually occupied, (O’Farrell, 1986.)

The U.S. Fish and Wildlife Service statement that SKR was extirpated from 4,940 acres of suitable habitat at Fallbrook Naval Weapons Station and to the San Luis Rey River is not supported. Montgomery (1989, Guajome Park,) indicates SKR are present.

Rate of loss of habitat

The proposed rule assumed that present or threatened destruction, modification or curtailment of SKR habitat or range poses a threat to the species, but this cannot be proven or disproven. There is no knowledge of the historical abundance or range of SKR, and the errors that are now apparent with today’s information confirm that the SKR’s range and abundance in 1987 were greatly underestimated.

Impacts from rural development and agriculture

The ability for SKR to inhabit and colonize both grazed lands and farmed fields has not only been demonstrated through the increased research attention focused on the species since the federal listing, but was even known at the time of the listing. U.S. Fish and Wildlife Service stated that SKR is restricted to insular patches at edges of plowed fields but offered no citation and ignored evidence that SKR immediately reoccupies plowed fields.

U.S. Fish and Wildlife Service is entirely inaccurate in its statement that grazing, off-road vehicle use, and rodent control programs all reduce habitat suitability. Grazing has been well documented to improve the open grassland habitat of SKR and in fact is cited by U.S. Fish and Wildlife Service as the pre-European-man basis for SKR survival. Off-road vehicle use has likewise been shown to promote migration and spread of SKR populations, with SKR documented to travel distances by way of dirt roads and trails, and daytime use of ORV trails has little impact on the nocturnal SKR. Rodent control programs have been reduced and refined to limit the threat to SKR. Rodent poison would have to be used illegally (according to current labeling regulations, independent of the federal Endangered Species Act listing) in most cases to harm the nocturnal SKR.

There is also evidence that U.S. Fish and Wildlife Service personnel working on the listing package knew of the positive effects of grazing on SKR habitat and the ability for SKR to persist in and around agricultural fields. Yet the proposed and final rules ignored this data and even implicated grazing as a factor causing the species’ endangerment.

An example of either an unwillingness to look at information objectively, or an indication of complete misunderstanding of the facts as presented, is evident in the following passage from materials in the administrative record:

“An important aspect of SKR habitat is its seral or successional nature. Most SKR sites are open, somewhat disturbed areas. Grazing, past agricultural use or infrequent fires keep the habitat at a state usable by SKR. Succession to denser shrub growth apparently excludes the small mammal from the site. This relationship of SKR habitat with vegetation dynamics may explain the local and shifting nature of SKR populations. Calculation of acres of habitat are, because of this aspect of changing vegetation, rather ephemeral in nature. Also, the management of SKR habitat must address the need to keep the habitat open. The alteration of past management practices which have kept the habitats open might well result in elimination of habitat after a brief period of time.”

The telling evidence that U.S. Fish and Wildlife Service personnel ignored or did not understand this crucial bit of information that did not fit their preconceived notion about the pristine habitat requirements of a species is the handwritten word “huh?” appearing in the margin next to the preceding paragraph. The handwriting appears to be consistent with other notes throughout the documents used in the listing package for SKR by the U.S. Fish and Wildlife Service staff person preparing the listing. In any case, there were no references to this passage made in either the proposed or final rule on SKR. There are other, similar notes that reveal this bias on other documents in the listing package.

A bias against any information presented that did not fit the U.S. Fish and Wildlife Service position that SKR should be listed as endangered is also illustrated in another passage contained in the above referenced study:

“Preservation of what appears to be many hundreds of additional acres of potential SKR habitat at Lake Henshaw is fairly well assured since watershed protection, grazing and SKR habitat preservation are all compatible efforts in this instance.” This paragraph had a large question mark next to it and was not included in the proposed rule.

Another study by L.F. LaPre indicated the prevalence of misinformation about SKR before the increased scrutiny brought about by the federal listing. In a biological report dated August 31, 1983, LaPre made several comments about the ability for SKR to recolonize disturbed areas.

The study focused on a parcel of property, portions of which had recently been disked for agricultural purposes. In a general assessment of the environmental impact of the cultivation, LaPre indicated his opinion that the damage done to the SKR habitat was significant and would require active rehabilitation measures along with years of regrowth and repair. LaPre wrote, “In my experience, repopulation of a cultivated area by these rodents requires about ten years.”

Later in the same study, he made a statement that is on both sides of the same subject. He stated, “In previously uncultivated areas, signs of kangaroo rats are abundant, whereas there is virtually no chance of occurrence of these rodents on lands plowed within the past five years.” This statement contradicts his earlier assertion that it would take ten years for SKR to recolonize the site.

The inaccuracy of LaPre’s assertion was revealed in a 1984 study by University of California, Riverside, graduate student Narca A. Moore-Craig. Studying a population of SKR on the San Jacinto Wildlife Area near Lake Perris, Moore-Craig found that, among other things, SKR will recolonize an agricultural field in as little as eight months of cessation of cultivation activities.

Moore-Craig found that, “Both one stephensi and three agilis were captured on the site, within 8 months after cultivation ceased. The released rats all entered burrows within the disturbed area.”

Another case of the ability for SKR to quickly inhabit agricultural fields is illustrated by the Domenigoni family’s experience with SKR occupying a fallow field of more than 800 acres within one to two years of cessation of cultivation. U.S. Fish and Wildlife Service restricted the Domenigoni family from farming this property until November 1993, immediately after the devastating California Fire. U.S. Fish and Wildlife Service biologist John Bradley stated SKR had left the field prior to the fire because of the overgrowth of brush and litter, which was a direct result of the U.S. Fish and Wildlife Service restriction on clearing or cultivation.

SKR has also been shown to inhabit grain fields during the crop year. The Domenigoni family also leases property where they were restricted in their cultivation activity on a field that had been harvested only five months earlier. The Domenigoni family was ordered to stop their farming activity because of the presence of SKR within the active grain field.

Statements that SKR were found in abandoned vineyards and citrus groves recently acquired by Riverside County Habitat Conservation Agency have also shown the ability of SKR to inhabit more intensively-farmed agricultural lands.

Encroachment by heavy, weedy undergrowth presents the greatest threat to SKR as a direct result of U.S. Fish and Wildlife Service restrictions on human activities such as agricultural practices and firebreak clearing.

U.S. Fish and Wildlife Service reference to a State Recreation Area rodent control program as a threat to SKR disregarded the opportunity, through government agency cooperation, to manage this program to minimize risk to SKR through a diurnal treatment schedule. The U.S. Fish and Wildlife Service statement suggests that it was purely a guess.

Consultants’ observation of the unexplained disappearance of SKR sign and the unsupported hypothesis that this was a result of rodenticides is unsupported, appears on the face of it to be merely a guess, has been shown to be incorrect, and appears to be a weak attempt to convey an over-exaggerated threat to the species. Subsequent research shows the SKR to be dynamic in its habitat utilization, and disappearance of SKR sign without other supporting evidence is inconclusive.

Urban growth patterns

The proposed rule presumed that rapid urbanization in the range has resulted in elimination of entire populations of SKR. However, U.S. Fish and Wildlife Service has failed to show linkage or prove fragmentation. Despite the rapid urbanization, SKR managed to survive and thrive in elongated patches and supporting dirt roads, and they have generally managed to have gene flow over hundreds of generations and years of this supposed isolation since the presence of agricultural development occurred before the turn of the century.

U.S. Fish and Wildlife Service greatly overstated development pressure in the Lake Mathews area when it argued that SKR is likely to be extirpated from the entire area because of planned housing and agricultural development except for the 2,500 acres in the Lake Mathews ecological preserve. In fact, there has been an expansion of SKR and new discoveries of occupied habitat in that area.

U.S. Fish and Wildlife Service concern about infrastructure development is disproven by the experience with the Devers-Serrano power line right-of-way, where populations increased around disturbed areas, and by research by O’Farrell and others showing linear characteristics of SKR populations throughout history.

The proposed rule made several incorrect assumptions regarding loss of populations. It wrongly assumed that, because 78 percent of the sites where SKR had previously been found were now zoned for “incompatible uses,” 78 percent of the SKR population would be eliminated. This assumption ignored the fluid characteristic of SKR habitat occupation. U.S. Fish and Wildlife Service assumptions about compatible uses have been disproven.

U.S. Fish and Wildlife Service provided no explanation or definition of compatible and incompatible zoning in the proposed rule.

The U.S. Fish and Wildlife Service assumption that zoning can be changed is an inconclusive proposition. U.S. Fish and Wildlife Service always says protective zoning is not a strong enough indicator of protection of species. By the same argument, land use agencies have been known to “down-zone” lands in sensitive areas, providing increased protection of species.

U.S. Fish and Wildlife Service only cited zoning in Riverside County to support listing even though approximately 50% of the SKR populations (RCHCA short-term 10(a) EIR) were already protected.

The U.S. Fish and Wildlife Service statement that Riverside County’s open space zoning is not adequate is unsupported. U.S. Fish and Wildlife Service incorrectly assumed that all human activities are incompatible with SKR when it stated that “only a small fraction of the involved land is currently zoned for uses compatible with the k-rat.”

Conclusions

Petitioner disputes the U.S. Fish and Wildlife Service contention that it assessed the best scientific and commercial information available, when in fact U.S. Fish and Wildlife Service omitted numerous specific examples of favorable information, information that subsequently appeared in files made available to petitioner in response to a Freedom of Information Act request, (Friesen, TMC, and O’Farrell, Warner Ranch, and solar facility.)

Petitioner disputes the legitimacy of the U.S. Fish and Wildlife Service decision to list SKR as endangered, based on “phonecon notes” of Karla Kramer, principal author of the proposed rule, and Ron Novak of U.S. Fish and Wildlife Service office of Endangered Species, in which the two persons casually and individually made an arbitrary and unsupported decision to list SKR as endangered rather than threatened.

Petitioner disputes U.S. Fish and Wildlife Service assumption that all human activity is detrimental to SKR, when in fact various human activities have been well documented to be beneficial or to have negligible effects on SKR. These activities include grazing, off-road vehicle use, certain agricultural practices including disking, and some rural development. By assuming all human activity is detrimental, without defining the type of human activity, U.S. Fish and Wildlife Service has overstated the threat to SKR, inaccurately analyzed the history of SKR habitat and failed to demonstrate that SKR population is significantly declining; in fact, restrictions on human activity imposed by U.S. Fish and Wildlife Service have contributed to a decline in suitable habitat.

Petitioner disputes U.S. Fish and Wildlife Service assumptions about the extent of development activity and the threat which development poses, when U.S. Fish and Wildlife Service has disregarded important portions of scientific information available to it and has failed to correctly analyze the impacts of human activity.

Petitioner disputes U.S. Fish and Wildlife Service reasons for not determining critical habitat for SKR, where the issues outlined by U.S. Fish and Wildlife Service have been refuted as not being significant threats. U.S. Fish and Wildlife Service assumed land owner disking would extirpate SKR, when in fact disking has been shown to maintain suitable habitat against coastal sage scrub encroachment and to encourage population expansion. No land owners with SKR-occupied habitat were notified of SKR presence until after suspected Section 9 violations. U.S. Fish and Wildlife Service accepted as fact an unproven hypothesis that rodenticide use was responsible for disappearance of SKR sign in certain areas while disregarding known facts about the dynamics of SKR habitat use and migration.

Petitioner disputes that U.S. Fish and Wildlife Service has adhered to the Endangered Species Act, because U.S. Fish and Wildlife Service has failed to initiate a species recovery plan for SKR.

Petitioner finds that information developed since the original listing shows there were gross errors on the part of the U.S. Fish and Wildlife Service in underestimating the population, range, and persistence of the species.

Petitioner further finds that the U.S. Fish and Wildlife Service erred in exaggerating the threats to the species’ existence.

Because of the evidence presented herein and by Riverside County Farm Bureau, Inc., in its delisting petition and supporting documents of 1995, and  because of the extensive habitat preservation by Riverside County Habitat Conservation Agency, Robert Eli Perkins submits this petition to delist the Stephens’ kangaroo rat under the Endangered Species Act of 1973 and its amendments.  Petitioner specifically requests a 90-day finding as required under  the Endangered Species Act of 1973 and its amendments. 

Robert Eli Perkins