51302 Federal Register / Vol. 58, No. 189 / Friday, October 1, 1993 / Proposed Rules MOTOR CARRIER RADIO SERVICE agricultural, commercial, and - maritime chaparral in Orange County is FREQUENCY TABLE—Continued recreational development. Severalof disjunct and the species composition is these plant taxa are also threatened with slightly different from that found in San Freq~Jency Class of Umitations stochastic extinction by virtue of their Diego County and Mexico (Gray and small population size and limited Bramlet 1992). distribution. This proposedrule, if Two of the subject taxa are frequently made final, would extend the Act’s associated with southern maritime 44.36 do 5,6,23 protection tothese plants. The Service chaparral but extend into other plant seeks data and comments from the communities. Verbesina dissita is 44.40 do 5~6.23 public on this proposedrule. restricted to ruggedcoastalcanyons in DATES: Comments from all interested association with San Onofre breccia- parties must be receivedby December derived soils in the southern maritime 44.46 do 1,23 30. 1993. Public hearing requests must chaparral of southern Orange County. 44.48 do 1,23 be received by November 15, 1993. California. This taxon also occurs in ADDRESSES: Comments and materials limited numbers in Venturan-Diegan concerning this proposal should be sent transitional coastal sage scrub (Gray and to Field Supervisor, U.S. Fish and Bramlet 1992) and southern mixed (c) ** Wildlife Service, Carlsbad Field Office, chaparral (Holland 1986). Verbesino (23) Thisfrequency is also used on a 2730 LokerAvenue West, Carlsbad,~ dissita occurs disjunctly insimilar secondary basis for cordlesstelephones California 92008. Comments and vegetation associations from Punta underpart 15 of this chapter. materials receivedwill be available for Descanso southto San Telmo in public inspection, by appointment, northwestern Baja California, Mexico. [FR Doc. 93—24090 Filed 9—30—93; 8:45 am) during normal businesshours at the Baccharis vanessae occurs in southern maritime chaparral in the vicinity of BIWNG COOE eiia—oi-ia above address. FOR FURThER INFORMATiON CONTACT: Mr. Encinitas, central San Diego County, Richard Zembal, Deputy Field California, and extends inland to Mount DEPARTMENT OF THE INTERIOR Supervisor, at the above address Woodson and Poway where it is (telephone 619/431—9440). associated with dense southern mixed Fish and Wildlife Service chaparral. One population of this plant SUPPLEMENTARY INFORMATION: occurs in the Santa Margarita Mountains 50 CFR Part 17 Background of northern San Diego County. Five of RINIOIS-ACOI the six taxa are found below 250 meters Three of the six plant taxa (iii) (820 feet (ft)) inelevation in the (Chorizanthe orcuttiana, Corethrogyne Endangered and ThreatenedWildlife United States. Arctostaphylos filaginifolia var. linifolia, and Dudleya glandulosa ssp. crassifoliareaches 730 and Plants; Proposed Rule for Six bloch.maniae sap. brevifolia) are Southern Maritime Chaparral Plant m (2,395 ft) elevationin Baja California, primarily restricted to weathered Mexico. Baccharis vanessae is known to Taxa From Coastal Southern California sandstone bluffs in association with or and Northwestern Baja California, occur at 880 m (2,887 ft) in elevation on inmicrohabitats within southern Mount Woodson. Mexico maritime chaparral. These three species It has been estimated that AGENCY: Fish and Wildlife Service, are endemic to south-central and approximately 900 acres of southern Interior, southern coastal San Diego County. maritime chaparral occurred historically AC11ON: Proposed rule. California. A fourth taxon in Orange County (Roberts 1992b), (Arctostaphylos glanduloso ssp. while about 21,000 acres of southern SUMMARY: The U.S. Fish and Wildlife crassifolia) is also primarily associated maritime chaparral occurred historically Service (Service) proposes endangered with southern maritime chaparral in in San Diego County (Oberbauer and status pursuant to the Endangered San Diego County, California; it also Vanderwier 1991). Currently, there are Species Act of 1973, as amended (Act), occurs in disjunct populations in an estimated 600 acres of southern for four plants (Arctostaphylos northwestern Baja California, Mexico, at maritime chaparral in Orange County glendulosa ssp. crassifolia (Del Mar least as far south as Mesa el Descanseo, (Roberts 1992b) and 2,530 acres in San manzanita), Baccharis vanessae 50 kilometers (km) (31 miles) north of Diego County (Oberbauer and (Encinitas baccharis), Chorizanthe Ensenada. Vanderwier 1991). Thisrepresents an 85 orcuttiwia (Orcutt’s spineflower), and Southern maritime chaparral (Holland percent decline in southern California Dudleya blochmaniae ssp. brevifolia 1986) is a low, fairly open chaparral that is largely due to agricultural (short-leaved dudleya)) and threatened typically dominated by Arctostaphylos conversion and urbanization. Much of status for two plants (Corethrogyne glandulosa ssp. cz-assifolia, Ceanothus the remaining 15 percent of the United filaginifoliavar. Jinifolia (Del Mar sand verrucosus (wart-stemmed ceanothus), States portion of southern maritime aster) and Verbesina dissita (big-leaved Xylococcus hicolor (mission manzanita), chaparral is located on Carmel crown-beard)). The six taxa occur Quercus dumosa (Nuttall’s scrub oak), Mountain in San Diego County. The mostly on private lands in coastal Cneoridium dumosum (bush rue), distribution of southern maritime Orange and San Diego Counties, Rhamnus crocea (red berry). chaparral and related associations have California; two taxa extend southInto Dendroinecon rigida (bush poppy), and also declined significantly in Baja northwestern Baja California, Mexico. Yucca schidigera (Mojave yucca). California. Mexico, for many of the same These six taxa are threatened by one or Southern maritime chaparral is a plant reasons. more of the following: Trampling by association that occurs onlyin coastal The natural plant communities of farm workers or recreational activities; southern California along the immediate coastal Orange and San Diego Counties fuel modification; competition from coast of San Diego and Orange Counties have undergone significant changes alien plant species; and habitat and northwestern Baja California, resulting from both human-caused destruction due to residential, Mexico. The distribution of southern activities and natural occurrences. The Federal Register / Vol. 58. No. 189 / Friday, October 1, 1993 / Proposed Rules 1303 rapid urbanization of southern Orange cushingianc but the more truncate leaf- known numbet in San Diego Cocntv A County and south-central San Diego bases, the usually more tomentulose significant number of these pop~iia’~cns County have already eliminated a lower leaf-surfaces, and distribution have beêr~~e~erelyimpacted over ~he significant portion of the southern seem sufficient to maintain it as a last 12 years. For example, in 198~’,one maritime chaparral and some of the variety ofA. tomentosa.” J.E. Adams in population ø;~nearly 500 individuals populations of the proposed plant taxa. his 1940 treatment of the genus and its scutharn maritime chaparral Remaining southern maritime chaparral Arctostophylos returned var. crassifo!ia habitat was cleared and converted to and populations of the proposed taxa to Arctostaphylos glandulosa as in agriculture. The cultivation was active have been subjected to a considerable Jepson’s original treatment (Knight for one season and has not been degree of fra~mentation. 1985). continued (Thomas Oberbauer, Planner, Although five of the proposed plant In 1968. Philip V. Wells declared that County of San Diego, pers. comm. taxaare largelY restricted to the United “jolther morphological variants of the 1992). Currently, fewer than 8,000 States. 85 percent of the known A. gianduloso complex have largely individuals, scattered roughly populations of Verbesina dissita are ailopatric geographic distributions and throughout the historic distribution of known from northwestern Baja are recognized as subspecies” (Wells the species in San Diego County, are Califorria, Mexico. Although the status 1960). Accordingly, Wells applied the known to be extant, The number of of this species and its habitat in Mexico name Arctostaphylosglandulosa ssp. individuals in Baja California, Mexico. is not as well documented, over 20 crassifolia to the Del Mar manzanita. is not known but is likely to be smaller percent of the known populations have Subsequent taxonomic review (Munz than in the United States based on the been eliminated and at least another 20 1959, Munz 1974, Beauchamp 1986) limited availability of habitat. percent of the populations are under have preferredthis treatment. In 1965. Four populations totaling some 3.000 immediate threat. Agricultural Walter Knightsummarized the individuals in the vicinity of Mirarnar conversion, resort and residential taxonomic history of the Del Mar Reservoir have been attributed to development, arid wide fuel breaks and manzanita (Knight 1985) and came to Arctostaphyios gianduiosa ssp. slash and burn practices have already the conclusion that the subspecies crassifolia, but Wells (pers. comm., affected and continue to contribute to should not be recognized. Knight (1985) 1992) maintains that these plants are not the decline of V. dissita in Mexico stated that the Del Mar manzanita was representative of the subspecies. Ifthese (CaliforniaDepartment ofFish and a product of hybridization between populations should prove to be Game (CDFG) 199O~. Arrtostaphylos glandulosa