BLM LIBRARY 88005150 PLANT RESPONSE PARAMETERS TO RECREATIONAL 7EHICLES IN THE CALIFORNIA DESERT CONSERVATION AREi (CDCA) m * 7*^773 L3S* Final Report: "Plant Response Parameters to Recreational Vehicles in the California Desert Conservation Area (CDCA)" June 30, 1978 Earl W. Lathrop Loma Linda University Loma Linda,- California for Bureau of Land Management 1695 Spruce Street Riverside, California 92507 Contract CA-060-CT7-2824 Bureau of Land Management B'dg. 50, Denver Federal rw °enver, CO 80225 ter TABLE OF CONTENTS I. Introduction a. Purpose and objectives II. Methods A. Site selection B. Materials C. Aerial photograph analysis D. Ground analysis E. Statistical considerations III. Results A. General B . S i te Area 1 . Jawbone Canyon • Dove Springs Area 2. Stoddard Valley Area 3. Johnson Valley Area 4. Afton Canoyon, Kelso Dunes Area 5. Plaster City Area 6. Barstow to Vegas Motorcycle Race Area 7. Patton Camps, Essex, Needles IV. Conclusions ( Summary table and figures) V. Bibliography i/I. Appendix A. Plant list B. Photo and species field calculations 1. Calculations 2. Symbols C. Plant community classification D. Study site locations E. Aerial photograph calibrations F. Plates I . Introduction Purpose and objectives. The overall purpose of this project was to study disturbance spectra to arrive at a basis for predicting the effects of recreational use on desert ecosystems, which would help federal land managers intelligently decide how to allocate desert lands for various uses. Specific objectives were to attempt to contribute information which would help to answer questions o.f the following types: 1. What kinds of recreational impacts occur. 2. What kinds of plant responses occur. 3. How does the intensity of recreational use relate to the extent of plant response. The objectives above were to be determined primarily from aerial photographic analysis with on site measurements to fill in certain places where photos were unavailable or to supplement the photo data. II. Methods A. Site selection The time period set for completion of this- study did not permit the execution of a carefully designed study projecting far into the future but instead had to rely on interpretation of recent and past experiments inadvertently performed. The seven study sites (appendix D) were selected specifically with a history of recreational and, in the case of area 7, World War II (WWII) use. These sites were selected by Dr. Hyrum B. Johnson and Tad Taylor, Desert Plan Staff, BLM. Contrasting areas such as motorcycle races, intense hill climbing areas, dunes and WWII tank training areas were selected to provide representative vegetative, geographic and use characteristics. Ground photographs were taken at each area depicting a spectra of disturbance sites and controls (appendix F) . B,, Materials Materials consisted mainly of items needed for analysis of aerial photographs and film, materials for ground transect and plot measurements, caluclators, and four wheel drive vehicles for reaching field sites. Most of the items will be mentioned in the photo and ground methods sections. Symbols and calculations used in aerial and ground analysis are listed in appendix B. C. Aerial photographic analysis. Study areas were located on aerial photographs for both test and control sites. The ideal control was a comparable photo befo disturbance, usually 1952-1953. These dates were too recent for area 7 (Patton WWII camps) however. In cases where a control photo was lacking, a site on the test photo that was in an undisturbed location with the same vegetation type and physiognomic character as the disturbed site was used as a control. Dates for the test (disturbed) photos were usually early to late 1970's. Uncalibrated aerial photos were calibrated by comparing exact ground and aerial distances between known landmarks. Transparent dot and plot grids were calibrated for each photo (appendix E) for the purpose of measuring total density and cover of perennial vegetation in test and control plots. The ratios for prints and grids were calibrated for each elevation level. For measurements of total density the transparent grids were placed over the sample sites and the number of shrubs (visible with the aid of 4X magnifier lenses attached to standard stereoviewer) counted within transect plots (K). When control photos were available, the grid was placed in the identical position on both test and control sites. Density was calculated by standard procedures using the photo and grid calculations previously determined. In most cases, density was expressed as density, no/. 04 ha or .12 ha, depending on the calibration ratio of the photo. When either the test or control photo lacked a suitable "stereo pair", the transparent grids were used with a regular stereo dissecting microscope for density counting. The extra magnification of this type of scope tended to off-set the loss of contrast so valuable in the stereoscope. The sample size for most of the study sites is indicated by K and N (number of shrubs or plants counted) in the tables of results. Cover was measured by use of a calibrated line transect divided into ten sections and superimposed onto a Bausch and Lomb Filar micrometer eyepiece attached to a standard stereo dissecting microscope with a magnification factor of .7. A moving needle calibrated in increments of .001 was used to measure the vegetation on the transect line which was placed over sample sites of both the control and test photos. The sum of the vegetational distance was divided by the length of the transect line (1000 micrometer units) and multiplied by 100 to yield the relative cover on each transect line. This method of estimating cover of perennial vegetation on photographs has the advantage of more accuracy than estimating distance covered on a line with the standard transparent grid. The needle of the micrometer can be placed directly beside a shrub, the micrometer reading taken, and then moved to the opposite side of the shrub and read again. Sample site selection on the photos considered such criteria as homogenity of the vegetation, presence of a disturbance type and the ^presence of a matching undisturbed area for control (usually an earlier photograph taken before disturbance). Samples; were taken in several different disturbance categories, such as pit areas, hillside and level trails, raceways, tracks, etc. While it is impossible to detect and measure eyery shrub that is visible on a comparable ground site, the photo analysis tended to yield similar trends as the ground measurements did. Thus photo and ground measurements are shown together for many areas but always in separate tables or graphs. \ D. Ground analysis On site measurements were taken to supplement photo analysis in a few representative areas but not in all of them. In a few cases (Afton and Jawbone Canyons, and Stoddard Valley) ground measurements were taken because of the unavailability of aerial photographs of disturbance sites. Ground measurements, like the aerial photo analysis, were used primarily to calculate density and_ cover. Since it was possible to identify each species on the ground, percentage composition tables were also prepared. Most ground sites were measured for density and cover of perennial vegetation in various disturbance and community types and also in a comparable nearby undisturbed plot for a control. The point-quarter method was used for most areas, sampling at a minimum of 30 points (K) for each disturbance type or control. Density and covere* were calculated from field data following standard formulas for such calculations (Brower and Zar, 1977). Some areas, such as Jawbone Canyon and Dove Springs, where large expanses of denuded vegetation discourage use of the quarter- method, line transects were used. Density and cover were calculated by standard methods also outlined in Brower and Zar (1977). Measurements of vegetation in creosote bush scrub were taken Dec. 11, 12 and 18, 1978 at the starting area of the Barstow to Vegas Motorcycle Race of Nov. 30, 1974 near Yermo, California, for the purpose of testing edge effect of motorcycle tracks (Tables 1 and 7, Fig 1, area 6) . , Edge effect was tested for by 1500 point samples at 75 randomly selected sites along 3 transect lines. One transect contained 10 tracks (sparse), a second contained 38 tracks (dense), both through the race path. A third transect containing 45 tracks was through a pit area. Cover and composition were determined following standard formulas for point measurements (Brower & Zar, 1977). E. Statistical considerations Limited statistical analyses were made for a few representative sample sites measured on aerial photographs. The quarter method and the line transect method of the ground measurements do not lend themselves to an evaluation of means from which the statistic summaries are based. (See statistical summaries in selected area tables and appendix B for symbols). Standard error of the mean (Sx) was determined for some bar graphs of aerial photo analysis but is available as yet only in the raw data on file at Loma Linda University. The formula for determination of percent change of vegetation in relation to disturbance intensity = test - control r control X Ij . Results Results are shown primarily in the form of tables and graphs for each study area with summary graphs depicted in the conclusions. In general, the impacts of recreational uses, primarily by recreational (RV) and off-road (ORV) vehicles, upon the California desert plants and their habitats cause negative responses by perennial plants. The degree of negative response varies with conditions and use intensity. Some positive responses were detected in annuals at area 6 where deep tracks in sand created an edge effect, collecting rain water and seeds in the swales of the tracks. Concentrated current or recent past vehicle use in localized areas tends to create the greatest negative plant response and one-time motorcycles races, with dissipated activity and with time allowance for plant recovery, appears to have the least negative response. Concentrated but distant past type use intensities (Patton's training camps) with long periods of time for recovery come somewhere in between these two negative response types (Fig. 18, Table 1 conclusions). Ground measurements tables of percent compositon data collected at some sites show differences in composition between control and test sites, indicating that recreational impacts do alter plant stability and diversity to some extent. Productivity also tends to be affected by recreational impacts as the data on cover changes between test and control sites indicate. Stabil ity tends to be reduced when recreational impacts are such that the dominance of long-lived perennials of a particular area is reduced or altered. The data from both aerial photographic analysis and ground transects indicate negative response by perennial vegetation to most types and degrees of recreational vehicle use intensities as studied in representative sample sites (areas 1-7) of the California Desert Conservation Area. See summary data tables and figures for areas and conclusions sections. Area 1 Jawbone Canyon Dove Springs s- > o 10 00 CTi CO r- CO CM CO CM -t-> •r— 0) o CTv r— LO KD cr» O ^~ CM i— m O in o o o o o o o o o o o o CM CM CM CM CM CVJ oo CO V) oo 4-> «3 '1— CD u «a OO ■M s- ;; -M 0) i— i— • CD -c o o 00 CD s- i- s- OO >> 4-> ■M (T3 C s_ c C Q. a; a;. o o 00 "w > o a • n ft m • O) CO a -M •r- •?— •F" • •r- •?" •f— 3= z n: 31 a. C- CQ LO O > 4-> TO 'a LO 0) 4-> c o c o >) c to o OJ c o JO to to 5- O LO to JO OJ to lo u 0) a. to «3" Cn «3- r^» *3- lo CM «3" i — CM • • • • • o r— co LO LO cm LO lo lo CM CM CM CM CO cn cn • LO CM cn CO CO LO CO CO cn LO LO cn cn CM CO CM O CM CM LO i— ■ p— i — CO i— CO CM CO CO f— o cn co co CM cn cn O CM CM LO «— «T cn i— i— LO cm cn f— r— CO CO lo 3 to Q. E TO u TO LO o E 3 •a to to o s_ to a. s_ TO u >> o a. x LO LO c CD C cn to E 3 LO +J TO •F- TO I— C i— •r- ai s- u ■»-> c < LjJ LO c 0) "3 > TO s_ "3 3 LO TO o LO TO LO E 3 O C O o e cr> a> •<- E to L_ o .3 s_ o LO TO 3 TO a J- TO TO to O O) TO c TO S_ M <— O TO U LO TO 4-> o i. CD > o o CD > 4-) 'cu ox < to O) CO CO ^^ LO en CM <* • • • LO Pv. r»^ LO "" CM «3- co CM i— CM UO O i_ +-> c o u LO LO LO o CO m lo f— to o CO lo en CO CO CM c o >> c -Q (O 3 C_) i- U to O) CO 0) c ■*■■ o CD u -2 C O) 2 •r Q. (T3 1— CO n to T3 CD S- < u «^- c s- o u > o O- X CD «o o to to n3 CU U o c cu E >> (T3 E IT3 or to E 4-> i- (O Q. to O S- -o cu •<- > Q. o CU u «o 4-> o a* X c a; o .6 .5 - .4 - .3- .2 .1 - S3 p i A. Sites A 30 i 25 I ^ 1 o <_3 20 15 10 5 - ill Ess B. Sites A 1 s- >> o r— O to to 5- fO C rtJ c CD re a. o JZ St- t~ 4-> +-> * +J i- ■a fO o a> cu 4-> c c -a O) •i— 3 en O) ^ r~ C > CO c -o ,— ro 3 c (C o o n s_ c CO CO xi c en 3 0) c S- S- •r" • O a> S- CO CO Q. a. to • SZ s. o CO o 0J 0) 3 M- > o en ^— ^ o #t CO a« UJ 0) -,_,- H- r^ (D O CO JZ s_ cc CJ OJ to > rtJ M c o a ut ■T™ u i- en ra CSi CO c I— r». re a> cr> a> CO #» r— E 3 fO • •r" m CO ■a Qi c r— a> c s_ CVi "O (O O o ••"■ •r- M- >1 co „— > .C •^ (0 r— 1—1 a; r— s: r~" s^ > re •^ {J -o X X -o O) a; > S- r~ "CJ O «t-> 3 o c s- c CO s. «^» 1 3 (O 4-> <*- o 0) c >, <+- c_> E o •M O u -r— c *^^« to -a j- E TO c c oj c a> ^— n en ■a S- A3 0) c a> ■a 0) o re r- 3 c •r~ -C II ST -t-> o -J oj —I (O s: "•— ' TO QJ XI re s- > O c_> - a; o oo cr* • « l-* r— CM CM in © «3- CO o o o O o o o O CM CM CM CM a. o LO ■a aj CU CU ai 4-> ■a -o -o »" •r" •r— 3 LO t/1 (/> C f— r— CU r— r— -o •^ •^™ J= -C >> T3 -o r— ^— CU QJ (O o ■a "O •^ s- 3 3 +-> -i-j C C s. c CU CD re o Q a a. o Table 2. Mean density, no./. 04 ha (N), of perennial vegetation before (Oct. 15, 1952) and after (May 27, 1973) use by recreational vehicles in Dove Springs Canyon, 38 Km northeast of Mohave, Kern County, California as deter- mined from aerial photographs. Transect sites 1-8 oc- cur progressively into the canyon starting at T29S, R37E, Sec. 20 and terminating with site 8 at T29S, R36E, Sec. 1. Density no/. 04 ha Srte K N 1952 1973 1. Pit area and hillside trails 180 2066 11.4 180 1699 9.43 2. Hillside trails 180 1727 9.59 180 852 4.73 3. Hillside trails 180 2086 11.59 180 1290 7.17 4. Hillside trails 180 2907 16.15 180 1070 . 5.94 5. Pit area 180 1876 16.45 180 751 4.17 6. Pit area 180 1989 11.05 180 937 5.21 7. Hillside trails 180 3456 19.2 180 1651 9.17 8. Pit area 270 3107 11.51 270 1744 6.46 in ca - O) > o C-J CO O! CD +J > •r— CO o s- +■> c o co (U •r- u CO CD en a. c CO •r~ -Q i. 3 O. i_ CO CO .c o 00 o 2 J3 •— CD CO 03 a d) a> i. — < <_> VO CM CM CT> CNJ VO CO C\J IT) CO LO CNJ 00 o co cm »— m CM CM CO o £3 «3- CM CO CM to CM CO CO r- CM CO CO CO r— CO 00 to CM to CO CM CM CO en CO CO «3" o CM CM CO «3 JZ a. ID U o s- 0J 03 .c a. to fO to to 3 O a. e a. 3 03 "O CL O 03 ■M (/J a. o E s- 03 -3 U E E 3 +■> 03 C 03 to ■a 03 s- C_> to c a> "3 n3 > 03 s_ -3 a) a. Lul 03 3 U to 03 3 o en 03 r— 03 03 to O c 3- to >1 03 S- o to 03 to 03 a; u o c o 3 CJ ■(-> CO 03 03 •<- S_ 03 IM «3 03 CO -a j- 03 +J O o cn >> (■* c ro ro • O •r- LO s- to aj cn ro • S +-> •r- E a s. O o Q. s- W) 4- D a -o ~ _ - > a) . .O to CD 0) -o C f— o o to «r- •^" ro +J =C ro 0) ro +J > •r* (U c Cn 1— S- a> ro o > c M- o •r" ,_* •f— ^~ ro +* ro ' «r~ ro O c > s. a) +■> > O M- jD O O > 00 S- +J 3 cu S*£ <"■■"» (/I .»—» • c CO it CM a> r*. CD •a > 0} r-~ ro I""- c x: -Q ro A o ro > o s: ■!-> ■*■— ' *5 CO o B ro CD . CO *_«* x: to -4-> -C JS s- j- Q. Q. a> o ro rO +j c i- i_ it- cn en ro ;g o 4-> s_ -a O CO e CO jr CO ro CO o. cn Density no/. 04 ha on fD to U1 un O Pit area and hillside ro EEIZZJ Bri-';yfiiiM.itnrM Br'irt'iin-'ifrir irniiil en cr> k*,:l, i Hillside Hillside Hillside Pit area —J Pit area Hillside CD Itii-nltiitii'f^tti'imTi il Pit area Figure 2. Bar graphs of linear density index (A) and mean percent cover (B) of perennial vegetation at recreational use areas of Dove Springs, 38 Km northeast of Mohave, Kern County, California. (See Table 1.) A. Sites CD "O •^ in .7 .6 X CD .5 C *^ .4 >) +J .3 00 CD .2 a .1 a; ■o •r- -a -a 3 c CD a -o CD XJ =3 C CD O •a a) -a C o 20 15- 10 CD -o to -a >^ s- B. Sites Area 2 Stoddard Valley ro 1 •r" ro C Cut a i- i- >i o to u 0) M- 4-> .o CU r— •r— o 3 s. r— r— r— S- • f0 (O CL U to c > O to ai •^ to •r- tJ fl -t-J x: 4-» c S- >> u to •r~ o ro +■> d) 3 c •r- "D C to XI 3 +J ■a 3 c E ro o o ro CO E 4-> +J o i_ ■4-> o <1> oo +-> o u en o to CD c c "O O .*—» > •r— •l~ c CO LO •o 3 i- ro i— CO s. o u ro ai ro s. • •»— +J c C3 e o c •^- s- •^" CO c to CD oo O) CD • CO V— - J- 0) Lfi r»- O) to c ro en ^ a. -3 ro r— c 1/0 -a •r— $- ,a> c A to o ^— n (O CO **- a 2 CM •r- •i— o r^ i^ CO sz •»-> OJ -a ro C oj CO c j*; re > s- A ro r— a> ro VD (O E "O CD CM «d- ro r— "U S- O <4- • c OJ s- O to >> (O > 1 O) 2: u M- to oo r»~ O a "O CM "O 2 •> cu C -a J3 3 s- ** (O c +J CM 3 v£> ro 3 to CM >> O a: ro +-> f«* to ai • •^ ro a E to CO C £ •zz. u c o ^c » CO a> •^ ^ oo o -t-> «3- I— %— . » cu «3 CM cu > o cr> en ir> cr> m r»* co <— O m en oo en CM co oo en o c cu a en LO en CM r*- o r— CM «3- V£5 • • • • • • 00 LO CO CO CM VO f*» o so i— ^ ^- p— cu ■o >> r— cu p— 3 {. •P" «o o -* . s- o J3 ro to S i- c «o S. r— cu 4-> •r" ■«-> CU +-> i— u C 00 +j c +■> •r- •*• • •r- a. c_> to T— o ro cu j^ s_ r— o < <4- un > 0) 10 ro o > s_ o re . ■a CD u 4J A3 01 c o 4- 1/5 r»» +J ^~ to en re r— c o J ^ (C •r- re «a- +J «d- •t— ^"■^ (0 c ' c O) A S- >, o J- >. o re •T" u . ■ C_) .ii Q. «^» re E "O >> 4-J O c i- +J o o re c to •^" ■a 3 •4-> a* +J -o o c *"—«' tT3 o c_> CD -M 4-> E S- a> CO o O) 0) en c i» > ai c •r— 3 o > •r— -a to u s- re ?■■■ re CD 0) re CD c E > i— +-> &. *^~ c mTm 01 ■a +-> c 10 a c (O ai 3 p— s_ 0) c O CD 0) lO re i- or a. 3 go cs • CO Of fm -O re rO i- rO (O s u ro s- (U > o z <_> to CD QJ +-> > »^- •^ co 4-> (tJ 0) r— -a 0) •^ IX co o c o >» 0) .0 00 f— 3 ai ^~ i_ •r— rC U o > to CO o CO CM o rO s~ d) o i- < on CM r— CM Lf5 CO on on o in CO on CM m CM CO en i— CO CO CO co «3- en co CM o o CO «3- o en i— CO on en o o CM CM co on on en CO O on co CO CM en CM on en co co ro on ro CO o E 3 ■a f0 •!-• CO O J- rO &. rO U o CL 0) i— fO CL i- •i— 0O CO (O ra -t-> fO E s- fa < fC £ to to •^ to o E rO s_ O) c CD o o fO r- fO o CO fO CO re CL) o c: a> ro C a) •a - cu > o o ro o <+- a> o r-" 2 im •r" O VO CO Ol j= ■)-> CM r- > ai co cr> o > s_ . o rO u -0 CO cu A +J ro CO c 0 «*- CM 0 s. 0 ■a u 1 2 "O i- «4- 4-> CNJ c zr 4-> ro 3 CT> >> O O ro 4J (D to r— s: c 0 £ •1 (O c cu ro •f"" •1— -^ ■M <5f C (O **^^ - (O i. •4-) c ai A O O j- >> «4- to •^* u CU •r» t— 4-> .a; r— ,__ c •^ s_ r— (O cu (/> ro O E O c > a> Q. ■P" ■ i_ E T3 >> =3 O c &. +J 1/) u 0 ra c ro •f" ■a 3 CU fc« 4-> "O O E ^— * ro 0 O +-> +j ■0 &» O) on O c cu en £ 3 > cu c •r- O 0 > •r- ■a S_ u i. CD ^-" «/l ro a rO CU c > •»■" ■M s_ . w" c •p- cu 1^ •M c to CQ CM ro cu r— s. CU c -a o o > > CD r— p— ro .O > 3 S. -a u s- co rC ■a CD ■a c 0 •^ +■> r— 00 ro -*: CVJ <— - < (T3 (U S- to r— CM co 10 Lfi C\J ro in co CO CO • cr> ro E CO (O a. zs •T— ^-« ro S- ■M CO O •M 5 fO XJ CO ro C E 1— c -0 &* "O Q. CO QJ •!■■ ro •r" CO C Q. CO s. s. to X ■a co ^— 4-> 0) •f— CJ •r— ro O > CO ^~ O i- ro O ro 0 0 CL •M ■a •t— C CJ u S_ •^ fO CJ >> CJ i- XI 1_ s_ j= ro s= S- ,— ^ 4-> < 0) a. UJ 31 rO _l ro 4-3 Table 4. Summary data of soil characteristics of Stoddard Valley study site, 4 km southwest of Barstow, San Bernardino County, California, T9N, R2W, Sec 26 and 27. Analysis by Al Endo. SUMMARY DATA Site Stoddard Valley 3 Physionomic Characteristics Elevation 2700 ft.^ Slope/aspect 4-5% SW Parent rock mixed alluvium Land-form Alluvial fan Surface conditions 80-90% loose gravel Consistency Dry, Moist, Wet hard very friable non-sticky, non-plastic Texture Surface GrS Subsurface GrS Sturcture Surface Stonrg med-course, platy Subsurface massive 2 c O •T™ -t-> c i. o fO •^" CQ 4-> fO M- ■M O 00 > E p-"" -* fO ■r™ <«■ E E •% O) >> i- Ol 01 fM Q. O «4- -a i- to fO c T3 ta ■O o> O • E +-> CO ^— «**«s B c 0) ,l»— * to fO 0) •r— O) > (/> a> "O co 0 05 to -0 3 c . (O 01 ra r^ •r~ <"■ ^ u c D 01 i. 0 «4- " — ' > r__ >> "O fO O •p" 0 , o» M- +-) ■0 H- c O 3 o> O c "O <_> •r" c 3 fa O O C -C t— ■i_ 00 re -a C i- J= O ro Q. •r— c TO 4-> i- S- fO cn 0J CO i- u c IS) i- u to CO =5 -£■ CJ o to o QJ i- •f- 0) C Q. s o eq/ou ^lsusq Area 3 Johnson Valley ■Jfi s_ 3 **- o QJ c/> o O 4-» m <— •» to c m «3 LU -fJ o ii m o o -o a: cu s- i"H CNJ H- 4-> +J CNJ in •^ II cr> •> en a. Lu .—i >, c a; •^ cu • * „ +j £ a CO t— « 4J O CNJ «o •t^ o > ■a H- CNJ s_ fO O II a> c i_ LU JO o • i- E to E cu • * 0) c O •M 0 > -C V. C O o O *4- CU CO •z. "-3 u r— * -o It «♦- cu cu a a> O c .c s_ ff *-> « a o s. t— I 0) 4- II C +J -o O o •r- to T" Q. to CU • * 4-> (O CU o (O ,_ u ID +-> c «f»" CU II CD o c TJ CO a •r— s_ > 4-> o to » * (0 <+- to a r_ cu •f"" «3 Lf> m i- r— Cl m «r~ • o o < C s- (J cu n cu s_ o +J CU S- a c to cu ^~^ cu «3 +J to vz. E CO ra c JE ro to o "O i- -o (C «3 a. to to c JZ CU S- ^-»» Cl o 01 ^ (O c r^ CO * tm >, r»» e to O -t-> tr> «j +-> 4-> •»-• t— t i/> O o CO r— sz c Ml M CL Cl a> CO CNJ • -o CNJ CNJ f— o (0 o c >> ■ T- tO fO (O u CNJ s_ m a> 2: cu «— t CU II s: to • (O 3= cu Density no/. 12 ha Site K N 1952 1977 A 89 1139 12.7 85 386 4.5 B 86 1093 12.7 86 529 6.2 C 90 1154 12.8 90 677 7.5 D 89 1125 12.8 90 740 8.6 E 90 815 9.0 90 414 4.6 F 90 730 8.1 • 90 440 4.9 G • 90 .1154 12.8 • 84 628 7.5 H 34 422 12.4 24 157 6.5 c o to E o . ■"3 M- O t/1 •^ VI >1 -o 3 4-> to C ■»■ >> 4-> ■r- to C 01 T3 5- O M- tO 0) 3 ^— c « • 01 CM £ -o «*- E O • ro to »-* e o to to a •^ u S- Z3 fl3 CT CL •T-" E U_ O u -o E **- ra o «— 1 >> s- a> re r~ E XI E (O 3 h- l/l a> r— a> > •^> a> +J F— « ^— +J A3 • CVJ O) ^^ .0 «o Values x SD n Paired-t yl? rS. > DF Pit area 1952 1977 11.63 6.23 1.92 1.44 10.05 7 .000021 CM en in c o •T~ i—i >> «3 A re 01 X •r~ X> c •r- S- E o m o> • CU in re e > C E O o JZ. o c CO z: o •~3 o en m re ii M- -o . cu n O CU re u_ .^^ (0 •^— • •* O) E 4-» o O) s_ s- •r- O &. (O 01 Q. 00 o +J l-H «+- -l-J 01 CU 0) •r— "O x II X) CL m ■P UJ c r— <0 <+- o (O o • •> •r- C re 0 4-> O •f— s_ O re c cu *T -PJ +J S- +■> t— t CU to o c en CU 4- cu II cu S- •r- o > u ^- O a «o cu ,__ s- o x •* (O +J o •^" «3 M m c 01 E o O. c cu in cu to cu • *•■ M- E re cu a o x CO s- in 10 Cn CO ^-^, o CU •(-> ^— c -a ti o XI •^ (O -o in CD cl 4-> S- in re re • ** (O 0) c a. o jC J» g= O ^^— . 0) o m CM r^» CD a CO l-H r*. . en c E II f— i fO o i- uo "O «c 01 n c a. CO n re 4-* CM CM S. u i_ CM cu 01 >> -t-> m J3 (O • re c E s: CJ re 3 0) *a S- C A in cu >— o ■ J? re >, 3 r~ • 4-> - -> i/l Q. m •T"» x: U) s_ A in Q. c cu UJ +■> re cu 4-» ' m o s_ -o «4- ca 01 en (O m o c A c 4-> (O -o z re o 0) c in s. sz 2: (0 l— +-> a. 01 s- =5 Density No/. 12 ha Density No/. 12 ha Density No/. 12 ha A 3 -) ■D Density No/. 12 ha ©^ © ro ran— ni i mi en O N en Density No/. 12 ha r-"-'n.- I ©- m s~r---^.-T ro O Qj eo 3 O n en i © L Cn ]ee:-:£.-:j en _J © to rr eo O ©. 3 O n ro 5 ** Density No/. 12 ha en _i ZD E Ix^it^, s-^223" en ©' en mm bs ----J' O o F 1ST mMtm 1 1 Figure 2. Mean density of perennial vegetation before ( Q November 26, 1952) and after ( S May 28, 1977) establishment of a recreational pit area of Johnson Valley, T5N, R3E, SW% sec. 22, San Bernardino Base Line, California as determined from eight radiating transects placed at random compass degrees from the center of the pit area on aerial photographs. See Table 1. «o >> J= 4-> •^ CM (/) »— I c • O) o o 15 n 10 - 5 - "5 ;• ■ *3 i J M • ; Sites ' Area 4 Afton Canyon Kelso Dunes -a o ■a (O £ a) o •r- s- i- T3 2 i S. to «4- re re <4- £ aj O E -o CO ^— V c _*: re £ <0 ^— u-> CO re +J £ M O o 2 n— •r- o a. -(-> 4-> re CO +J CD 5- U i- re ai O CO CO a> £ s- *4- re o im <4- 4-> o +J to "D e JO £ o a» 3 •^ j= O •M •*-> i- (C s- o +-> o • CU £ Ol - • a> E CO > J*. •"" ,_ -f— 1 , A3 «£> o • •f— a> JO £ M to 3 £ £ i- a O M O s- >, UJ to OJ £ Lf) a. (O -C CJ ca co s. 3 o £ ' •> JO M- O z 4-> o a) to «4- »— 1 +■> £ < o CO h- CO aj «4- o E O « OJ re s. S- to •r— u a> re £ > 0J U £ o S- o •r- u re «f- •r— 00 ■a a> ^— r««. c to re CTi re rs o i — >> OJ M A 4-> r— >> in ■*— O -<-> ^ CO •r- £ C J£ 3 >> aj . <_> s: 0) JO re o r»» in i — r>* CO VO CM «3" f— LD in i — P^ CM en CO cr> in ) C O) Q cri LP CM LT> lO i— CM cn r- -*f r— cn CO CM CO CM CO CM CO CM CM cr> CM m CM CM CO cu to +-> I I CO i- o s- J-> c o u I I to CU -a on a> ■M I I fO a» «3 O S- +-> C o u I cu s_ <4- 0) O r— o CO i. •r™ m r— O) o . o > 4-> u o CO 0) "O i- LO 4-> fO A3 c o CQ A CO 01 r— TJ A3 z: A3 c ro JZ CO o +J r»» 4-> i— i- 1— en A3 O r— T3 C c M C o A3 n A3 •r- E •^» IT) +J 2 C ,— ^— » to s- C (1) r— o >» o -i- VO <♦- A3 •t"" u •f— s: +-> ,— ■T" i- c A3 c to o (_> CD O C >> -*: Q. •T"~ c #» A3 E re >> 4-> o c <_) +■> u o c to •p- c 3 -t-> s« +J o O • c -*m^ A3 +J (_> O) +J <4- E t_ O) < . o a> c s- > 0) c •r- 3 O > •r- "O U) U S- A3 ^~ to fO CU 0) A3 (U c E > •P" +J i- T— c •r- 0) -a +J c to CO c A3 ^~ O i— O CO *rm > «r— re or re IS) o s- -4-> c o o CO a> c .a T— o 3 u >> im 0) c u a. re CO CO <~j j= c CO o 3 ■M X) It- 's: 0) +J ^- 0 co re O OJ CO CO r— CO r^. «*■ CO CO CO *3- r^» OJ <* 0 to CO CM •S3- »— <— O r*» r— " , CO en en CO CM en csj vo en csj p— , CM r— r- re re E CO 3 re sz 0. CO 3 •r- en i_ •r" d) co c re 4-> re CO 0 •!-• cu E •*— >> 0. CO >> co ■0 re CO S- s_ •^ 0 c re 4-> •^ CO CU re 'a; re CO r— O) s. re S. CO -O CO e u 0 O. c 0 +j re •r"- S- 0 O) 5^ E •r— re c 1— co 3 £ ^ E re CO CD 0) •^ 0 JS 3 ^ O i- 3 i_ co T3 co E -i-> -a O. 4-> •^ 3 •*™ re re X CO re co CO 1 — r— O D- Q. i_ .,- .,- JD i_ i- E •+-> +J ) en o OJ 'o u re u o o re cu u C 4-> re o_ re O OJ r— S_ a. t_ re re re c 3 Q. O i- X re c 1- o -m 1 — c re 3 -M O. 0) o o. 3* CU > O u re ■>-> o <+- 0) >> o ^— to u s: s- •r— 0) 0) o > J* u ra -o 4J .»-> (O c o CO a; S- 4-> o 1 c i- «4- 0) a> 4- E Q. O t— -a 3 (O c to 4-> (C re o a> +J «T3 E -o C ■o c o c ra •r— 3 4-> O •»--. ITJ J- c a CJ o s_ •r*» o 4-> 0) • •r- i. c t/> o O c >» Q. •r* c E to O C c_> o o •r" c >s 4-> o v_-« «3 -t-> -M «♦- J- • 0) < > O) e O > •r- u ^~ to • 03 •r- 4-> r^. •l— c •m CX> 4J c «/) r— «3 0) i— s_ QJ M a; a> oo in cc Q. 3 i— o O <_> > +■> re on (0 < co c o co . s- a> c o a. re V) co <~J .c c CO o S 4-> It -Q < *3- 4-> o CO re o Cn en Lf> «3- LT> «3" P>» en *— LfS <£> •""" en O r^. cn VO CM CO CO CO en in in m CM CM ^~ CM ■* LT) CO lf> CO o en o o CO cn O t— «a- • • » a • • • VO m ^r ^~ en o CO IT) cn ,_ en CM m CM vo en ■ re E CO • CO re O re to •^ CO O a. CO CO •r- re 3 &. f— C CO +j re (T3 re CO 03 c re Q. CO o o C 0) +-> O >> « E ' •r- ■o c re E ■M re cn re ■!■■ 3 'o (O s- S. > -o b_ *a a. E •^, re < o c >> cn o o re re •f- i_ re 0) CO > o u re o Figure 1. Bar graph of density (A) and cover (B) of perennial vegetation in creosote bush scrub at recreational vehicle use areas of Afton Canyon, 61 km northeast of Barstow, San Bernardino, California. (See Table 1). o o ro O c >) 4-> c a; o 2000 1 1600 1200 800 400 1 ro 0) -a S ^ o o I ro CD S- fO IV.SN Sites rC C\J 600n 500 400. = 300-1 > 3 200 100* B. Sites -a to O i- c o l_i fO a; s- Table 1. Mean density no/. 12 ha (N) of perennial vegetation before (Apr. 15, 1953) and after (June 9, 1974) use by recreational vehicles in the Kelso Dunes, T10N, R12E, sees. 3 and 9, San Bernardino Base Line, California as determined from aerial photographs. Density no/. 12 ha Desert floor Foredune Transect (K=90) N 1953 1974 1953 1974 1 1125 12.5 2 560 • 6.2 3 432 4.8 4 253 2.8 5 1252 13.9 6 621 6.9 7 321 3.6 8 176 1.9 9 659 7.3 10 N 290 3.2 11 386 4.3 12 217 2.4 13 488 5.4 14 250 2.8 CO CO 3 ■*-> CO to c 1—H n- O) o s. 3 >> CT s. •^ A3 Ll_ § T3 3 C co (d ,_ i— i « O <1> •f- r— ■ 4-> XI CO (O •f— (— 4-> «o a; +J CD CO CO • cvj 0) r- X) <0 ^r V£> in r*. ro *r cr> • • l-H CM o £= 3 ■o (1) u o U_ co CO o LD CM U3 CT> • • v£) ^h CM CM CM CM O o to CU •I" CO ^r r-* r^ r*. O CT> • • s_ 1-H ^ CM u o o o o r-" ■ ir> ^~ u_ en f— i o u_ CO ro +■> • • +J • • £_ «3- ro s. 00 •■P OJ > CU to to 1) cu Q ro IT) en O "3" o 0} c 0) s- o CO CM ro CO co ^ U3 •M 00 1 CD "O 3 IX Q cu CO im 03 > Cu IX o to 4-> I -o cu s_ Cu Figure 1. Bar graph showing mean density of perennial vegetation before ( D > Apr. 15, 1953) and after ( S , June 9, 1974) use by recreational vehicles in Kelso Dunes, T10N, R12E, sees. 3 and 9, San Bernardino Base Line, California as determined from aerial photographs. See Tables 1 and 2. * >. j= +J •»" CM in «— I c • a; ^■•^ a O 15 n 10 ■ 5 - Sites 1 F -1 i i 2 3 Desert floor t- CM (A «— I CU '-v. o o 15 i 10 5 • Sites P. 1 2 Fore dunes Area 5 Plaster City s- > e ■p CJ to •r— 4-> _^_^ <_> t/o ro S» IT) CJ • • tr> +J «d- i— i en ro » A r— o VO a. CJ CVJ S- CO -o ro A* e aj 3 to E oo CO ^-^ * «— 1 m i UJ 1— 1 >> «— i «— 1 ro • cu s CO *«*_*» 0) m +■> (S) o> f— CD S- CO «— i o x_^ r— 4- CJ CO 1 .Q ro CJ cnj| c S- o ro CJ •r- +-> 4-> -t-> •^ ro «^- oo *-> Cv CO • A O) r— IT) O) ro ^H > E O • t— •f- a (0 4-> 0) 1— ro CO c CJ E S_ J& CC « E *— ** cu Ml uz E 00 «_^ r ir> CO «-H (0 •^ h- • -E X) , »—i «a- ro • o 4-> »-«l O CO CO V, a> a CO O +j E *-*. •r- A* evi to 2 n r*. c/1 >> en +-> «— 1 • *• •r— ro UJ CO n •r™ O E VD E «— 4 •r- (S) ro O r— Lf) CJ z: ro <— I 2: w* O r— CJ .a ro «3" cm CO co LO CM oo cr> *3" CM CO H CO LO LO cm co lo w n in rr» co «a- O LO CO n n in CT> LO CM O CM O CM CO LO o o o cr> crv cr> o o o CT> CTt CT> (J O) LO s- »-H CM CO «— I CM CO CM I — cr> 0) CO en LO LO LO «3- LO LO t— 1 «3- CO LO CO o CM cr. ^J- LO LD CM LO LO «a- co r^. «—« t-»4 fs» «3" LO LO CO n n CM LO CO CM «3" LO O O cr> o CTi o o o cr> cr> o~> t-H CM CO CM CO CO LO cr> CM CTi CM LO CO LO CO en LO CM CO CO CO CO <3" LO LO CM CO CT> CT> CO CO CO LO co CO o cr> CO r^» LO CO o i— » cr» p*. CO CO CO CO CM o o o en cr> en o en o o Cn (T> ^h CM CO ^H CM CO CO LO en CM en CM CO •r~ S- o> 4-> to re to +-> •r- to >> XJ 3 -M to +■> •r- c cu to c o to •r" £. «3 Q. E O o <+- o • CN4 >) s- 1— " (O CO 1— • CO 0) ^— -Q (O CM r^ r>-» m cr> • m »— • m (O o> i. (a o CM r— I • o o CM CO CO en on CM T-* <£> ^. IT) 1 — CT> »-H IT) in CT> CTi • • 10 CM CM LO CM «=r r>» CO VO CT> • i r* .— 1 C"> i— i *C cu i_ fO CM cn CM CM IT) CT> <3" CM CO CM to 1 cu T3 =3 IX Q CU u_ 00 S_ o rt3 > a. N to CU 4-> re A* •r- si 3 tO =3 >- co CU A to 0) LU S-. JZ O 3 +J 1—1 O a: u c CD •T- A U CO re CM CO &- r«~ .-^ CM t— ■o r— 1 O) 1 4-> 01 o CO CM| CU f— s- * <*. 0) (1) CO tO E t— 1 s- 0) • 3 a 0 o a> <1) «♦- 0 CO- c -0 * •r" (— UJ CU 1— t C .c 1—4 • o a: 1— t •r~ 0) CM 4-» 0 « to re •z. • 4-> s_ CO u cu «— 1 CU o> r H- to a; O. 1 M >i LU r— +J r-»l <— t re «— 1 •r» CU • • cs: C 00 in c re 0) M a j= +j CO s_ u •r- CO a> CO !-* a. cu 1— «4- 0 • I O >> re . 1 . 0 •r— <3"l m 0 c •— «■ s s- • a i<£ 0 LO - _- JD «t- 1— » 3 •t~ +J r» ^— • o O re u r— u CU a. CU to 1— Ml re O >> M -C >i +■> LU O •t^ 1— 1 CM s- 0 1— 1 o 0 C£ o 4-> S- • O a> A -^ 2: +j CO o 1/1 vo c c re r-H 0 ^~ 1— #» •<-> O- >> re 1 -M <_> 5- ■f™ re CO (/) |— cu c LU e • •% O) ^r "O CU 4-> CM JZ s_ c 4-> CU * re to U aj M- CU cu 21 O 0 V) CO CU -O re o i- c o cr> CM cu u ro ro CO «3" CM ro C\J O O ro o i. c o o re re *3" ro ro 00 en ro cri CvJ o >1 +J to c GJ O CM o s- VO ro vo +■> IT) CO CO c • • • o »-H CM IT) o >s re vo 2 1-^ CO V£J OJ in • • u • «— 1 ro re cc O s- a\ +-> r». c • o C_3 >, re r*» 2 ir> QJ • (J ro ct CM ro «3- ro *-h o z U3 en „ , to o 0) CM +■> r^ ii to ^ (U to to - •<-> 3 a o QJ u to t— i CD c u ro ro s- cu (— CO CO in t— I CM ro Si 3 f— • O QJ O) o u- a QJ >> J2 u S- E o QJ 4-> ^ o ro z 4-> c: CO o JC •«-> a. • «3 «3 QJ t_> S_ U a> r0 r— o s- UJ 4-> o QJ QJ J= x: .c a. -M 4-> ^» ***+ -M rO C\J ro •r» r^ i- a* c QJ .— ( o rO •f~ •1 4-> E C\J rC O «-H +J s- 0) <+- • ai o a> ■a OJ > 0J Q c *— * r— » •r" ro E S- •r— 5- QJ C QJ +J c 4-> «+- QJ QJ ro s_ -o a> -o Q. in £ fO ra M- o <*»■> «*~^ cr> CM A r-» ^— » • CT> ^ C7> «— i ^_*« •r~ U- A +J re r— O JZ rO Z *t r— "O o *w^ c • »-H ro o ■z. QJ m +-> in m •r— a* >> •r» OJ #* ^— J3 ■ A3 * s CM . c cr> _ >! o t +J M s_ •^ CO +j t/1 e\j c c o OJ • u Q > o 2: ID o% \ o CO CO #» ' i- lo o CO -i-J • »— 1 c o vo VXD r— (J • r— s_ ex < cr> O co CO UD o CO C\J O 00 CT» O <— I CO CO CO CsJ co «a- u-> «a- «s- OJ o +J en •t— ti oo ^ C o (O •r- E re +■> O +j to J- •r- •^ «4- ^» S. •^ 0) -o XI +-> QJ re u r— X (0 •^ O) s. a. s- re E x: O o •^ 0) o u 0) -Q re u s- re -a i. c a re r— +j o c r— >> •r- o CD W> +J re. >> o c J= s: re a. c s: "O o "O 0) •<-j c ■)-> re re o o _j 0) ,— r— s- a> LU o W1 CM 3 «4- P»* re o crv 0) i— • S- (O 3 -t-> ■I CD re CO -a in • r*- >> a en • i. CD 0 fO co 4-> 01 01 CO to H- u_ r— 3 s- S- (U i" O •r— u (O r"~ r— r— ro e O •*" •^ ITJ ^O p— 0 U E CO CO S_ c rO a. u <4- m 0 a» j= ^« T3 O • M- 0. CO CO CM e LO ■0 E •— < 01 C ro 2 r^ rO •"" m 0) O 4-> 11 -^ O • -a 0) 4-> 3 u co «4- ■0 c CO O c O •i" CD •r" -O 0 s. 1— ^~ JO i- 3 >> "1-1 *o rO # ct- O E CO ■a I X) -a ■1 o cv CI) 01 O -0 co >) u CO -3 c -0 M a CD 4-> •^ 0) 4-> a) 3 •r— CO S. c X S_ 0 3 s- 0 3 a; 3 IJ- 0 . 0 s_ 0. 2 O 2: CO O •r- s. ro X O C_> »♦- 0 a. CO C_ 3 C_> 01 £Z ^~ 0 X M- CO M I ro rO CD 01 >> re 1 JZ •fM JZ 0) X) ■0 4-> CO S- 4-> >> i_ C •^ *« 0) S. CO ro r- CO <4- CL O r— r— rO • O CM O E c •^" ^~ 01 CO CO O 1— * JE CD £. 01 ro < II CO CO • _ JZ (O Q. ai 1 ro CO c 01 2: co CO O s_ c CO CD u i- t— o3 • c s- r— ro 0 -O i- •1— 01 •^ CO to ■I" -O 0) CO •r» C ro -UJ +-> E CO S- rO 3 J= e 4-* ro co CO on ro CT> p— " •^ •^ r— r— — CD LO 4-> - 3 •^ ro ro 4-> "O ^~ i- 2 CM a; O n -3 •T" 4J CO rO ro 0) LU E 0 co > C im CD E •M C ■ »— 1 01 01 3 3 Ol CO O •r~ O t— 1 co rO c E r— O CL n rO t— n ro 01 0 O r— E 3 ■0 -3 S_ 4-> r— O t— • s_ 4-1 CO ro OO c 4-> f0 S_ •r" l-H rO CO C (O •^ J= 0) -i-> 0 >> c >> s_ A —I 2 • <_> 10 O OZ +-> 4-> rO •r- -O 01 ro CO o> O i- ^~ C 4-9 4-> e "O -a o O r^ 01 O 3 ro CO • • •^ 01 cu c on 1—1 CO •r— co O) CO S- ^: CO rO ro M- rs. a) a ro S C O 0 s. co .c O f-H E 0 CO ^» >, O 1 t. (1) 3 « 0 01 i- J2 4- •^ O CO Q. a >- 4-> A" s. rO 3 Ol O 4-> 4-> CO c CO co <+- j= 0 > "O ro .,— x: S- •t— 0) ro ?— t 3 4-> O a co •r— ^~ a> 01 M- -C CD a 01 >- CO _-: CU O ^~ 3 4-> 4-> CO C7> "O c C f O •r— 0 c O 01 «— 1 C a C O ro CO CO q: c; •p- 4-> c x: «o -3 rO •p— r— ro CO 1 1 1 1 4-> r— 1 1 1 1 1 1 co 4-> M- 2 < 1 1 E c o 4-> rO O O 3 O • • •t-" >^ 4-> C7> ro O > r— 0) O 1— a; UJ 0 CO O to CO xj CU o u I I co <-> •r» 4-» CO •T— s- o to s- «3 -C XJ CU a> u r— CO sz CO tO to r— A 4-> j* o Q. 3 ■a ,_ O 3 c S. (O CO •r- •1— CO •*" o 4-> x> > o CO CU a x> CO x> c cu c c -o S. c CU •r~ > <0 o cu o •p» CO <4- • o to •p» CO o >, JZ\ 4-> CO p— c o M- to 0) cu CU •r- cu ^~ o r— CO s_ S- o cu • • o CO s. u a. CO cu CU +J co X. to tO c cu 5 .*£ c CU 1 O o "O o 4-> •t— (1) •rm 4-> 1 u u • •*■> cu ■Q •"" E CU O CU cu to c o a) x> •f— i_ > Q. CO •P" 4-> E cu CO 3 Q CO cu co •r- >> "3 s O £ o to CO p— o a o ^-« 4-> J3 (1) s. co s_ M- O c n a x» +■> CO -M to S- XI > a. -o to s_ J= X> a. O 4-> 4-> cu cu 1 cu M- *4- •^ ^ u CO -t-> E CO tO XJ O o r" to •M c to a> cu 2 CO +J * ^3 c to 4- jr. CO • 4J cu to £ CO -t-> +J CO c cn s- CU r— -a c s. cu c -Q cu s- #1 to C c cu to c= •f" •r- £ 01 CU •p- o . fO E CU & -a c »— a. cu > cu >» to e s- 3 s_ 3 E +j • > s- cu •4- •)-> t— u O cu r— o O p— a. cn co S_ ^: to r— JC • — -^ Ml •P" O CO o CD 4- p— o u LO -o t- CU E >> >> 3 O •p- 4-> o ^~ •B" CO X ■a o s. o J. •^ CU co +■> 1 c c s- a. CO a. to > cu •f^ 1 to tO • j= 3 ■a s- to XJ • c CO CO CO to +J +■> s_ c -M cu «^- S. 3 cu CD 3 • •, (O CU (O > cu E sz CT 03 JZ CO O CO p— p— cu o ■M E CO c • • C CO 3 sz +J 3 JD t— -C CO s_ lO o U o s- s. O 4- co •p— to K- to -o -o ■»-> >> r— 3 E 4- «o i» 4- CU > S- O s. c c cn f— to to c e X i- P-" 4J >» CO i •r— to >^ O) 4- CO tO cu CU fO cu cu CO cu -o •M co p- E CJ CO o p— 4-J u "3 CO -M o c to +J 0) o J- tO •p- CO ra •i- J* p— to •r— •r— >» c o cn +J CO cu Q£ CD 4- U1 O 3 H- 2 -o S- cu u c •M >> IO >> s_ to CO i- o o fO fO O o to i_ s- fO 3 o i- cu 3 >> CU 4- Q£ jD s: t— CU u. E CO 4-> +-> Ci . co JO cu • • s. 1 i -M 1 1 1 s_ r-H CM 3 4- JC CO 1 1 1 1 1— 1 1 o cu tO\ cu cn cu 1/1 cvj "O c o o I I to o •f— 10 •r- i- CO -t-> U (O s_ to O) •M o V) o 0) L. o 1 I •r* in «/l +-> c c O) (O +-> r-- X a. O M U CO O a o r" « (/I fO T3 u CD u +-> o C a> -C E —J at •r- > 2 (O a. A OJ >» en re 1 to s_ i- •i— 3 u_ CD 0> en re en c <1— • +J • c\J S- a. r* 05 (0 en ■M r— i— i 10 CO •*• 1™ " 0J ro r— • ^— fO •f— i- E cu CO jD (U r^» E F— • > C\J a> o o s_ ■p i \ o re c +-> 3 o to S- E a. (O 0) in -— +J i— « iO CM «a- Q 1 . 1 1 i 1 E -t-> cu o re a: Fig. 1. Outline map of the El Cajon Valley Motorcycle Racecourse ( — ) held December 3, 1972 in the Yuha Desert, Imperial County, California, showing study sites 1-4. R.IOE R.IIE. Plotttr Cit T.I6S. T. |7 S. Figure 2. Bar graph showing mean density of perennial vegetation in transects taken at three recreational vehicle pit areas at Plaster City, California. See Table 1. 12 i (T3 >> -C ■M •i- «3- i/> O C 0). *-^ Q O c 6- B i PP* to Jfc-rfL 2 . 3 Transect CO C o «3- o o e 12 n 9- 6- 3" 0 ^ t— - P F . ■ k— ! 12i Transect C o « <3- o o c 9- 6- 3- AJ ^T farJ B 1 Transect Figure 3. A. Bar graph showing mean density of perennial vegetation at racecourse site 1 (see Table 3) as determined from aerial photographs taken before (April 18, 1953 and Nov. 26, 1972) and after (Dec. 12, 1972) the El Cajon motorcycle race held Dec. 3, 1972 in the Yuha Desert near Plaster City, California. B. Comparison of mean density of perennial vegetation in control and racecourse sites of the El Cajon motorcycle race. (See table 3.) 6 • 5 - it? •i- ^r O A c • H » ^~ ^— u o O CO S- S- i- — 1 +J c C o o u ro ID CM CM o^ r»* r>» i— i •« CO M * T— 1 CM CM t— 1 r— •f— • • i- > U Q. o CD < •z. O Racecourse Site 1 4 n 3 - a) o rt3 CM §2 B o C o o O <0 C 2 c o O fO U 5- O s_ c o u u to r- >> o ia e u o «a Racecourse sites Area 6 Barstow to Vegas Motorcycle Race Table 1. Summary data of point frame samples (N=1500) of vegetation in sandy creosote bush scrub taken December 11,12, 1977 at random sites (75) along transects (3) through the Barstow to Vegas Motorcycle Race of November 30, 1974. Transect sites through race path located at site 2, T.11N, R.4E, Sec. 10, and pit area at site 1,.T.10N, R.4E, Sec. 6, San Bernardino Base Line, San Bernardino County, California. 00 u (13 O-l cu (J ro ce co in 00 *+- OO Ol CM r»» O ^ • • • U o> O l-H r^ 4-> tO ro ro ID =5 i- «sr O 4-> to -l* O <— 1 CTi cr> fO . • • s_ «— t 1— 1 LO C\J lO ro CM to +-> o cu to c (O 0 «5" *s- 3 s- CO 0 +-> to Jai. O in LT> a> ro • • • S- CM in CM 0 4-> cn CM ID t— 1 M- 00 >3- . O ^ • cn N out trac O CO in 1—1 O »— 1 ro cu CM in in s. • • • to «3 • • • T— J- 0 P*» CM O O. 4-> CM ro CO ro ro u u to cu S-. CO ro ITS Q o cu to c ro i- cu c 1 1 cu 0 00 to -Si 4-> e 00 u u u T3 ,-* A3 4-1 c .»- E s_ 4-> "3 ■O 4-> •«— l+- u- 5- 4-> E 1 -CT OO 0 0 0 to 4-> 4-> JC ~ C -0 CU •«-* ro 4-1 4-> O c •4-J 2 TO Q. ro f— to •f— cu to s_ 00 to ^ 2 TO cu CU O 4-> OJ e 4-> «3 cu CU ** •r— cn cu ■••» s_ cn cn to fO cu to -t-> • • cu cu > O > cu O 0 > > 0 ■z. < XI 2: z < <=c <_> cu cn t- ro cu pa -0 4-> £ 4-> O ro •«— u_ CO _J o 0) i_ o **■•* o Vi. Z "• — > O <4- u O "O to c .c fC Q. fO ^— ">» s_ IZ a> v^-* o •<-> >> o +-> _r ■T" Q. to • c a> r— CD u ro -o ro •t*- S_ s- o> OJ c Lf) a> a> en ^~ • >> 0) a o r— u ^— ^ (0 o .f— +-> s. c o -o 0) c <4- > ro O O ^_^ to 4-> «tf- r*>. to 2 a> >> o «— < 4-) (T3 to •a C i- U3 O P>- o JC a\ z CSJ ro CD > O 5* in C o o a o u o on CO 10 IT3 VO co CO •3- ro cm IT) CM <£> cr> CM co CO to CM CO CO CO CM o CM O CM CO a* CO O CM «3- o CM CO «3- 10 CM CO o CM C7> «3- CM Sf r»» «a- en r^ ■"" CTi o O CO z o CX> «3" * '"" CM •1 ■ • Nov o a u on UJ o cu oo as CO S_ ■a c ■4-> CO c 10 CT E CO O) cu .*: -a > CT o c «3 to (O CO c S- cu —I s: S- 4- o O ^o o 4- +J c cu fO s- JD 3 _i 0) o JD >» +-> M- E CO O 3 'cu S- C +J CD CO E r— c j_ JD •1— E -o CO cu c 4-> +J > IT3 c CO o cu CU z: »:r u 4-> r^ -i- cu cr> 0) o SI r— c_ 4-> +J O) s- u- .c • CU CO E S- S- CU o o +J J- Q. e •r— «+- CU o CO s_ •r— -a +-> "O cu O) cu E CU n— o c > 0) u o CO •r" e CO +J •r— E fO (T3 o 3 CU i_ cu r— CO <+- u 03 fO CU fO a: 0) s. +J u «3 cu -a cu •a ^~ c ■o o > >> ■«-> u s- u +j C (C "3 s- o cu s- E o fO u E -M Q. i. cu 3 o E cu .C to s: Q. +-> • OJ r-" -Q (O * - o •r- cu -t-> CO re «3 +J CU CU S~ Q> u 11) CD > Q &* <1J CO «3 CO CU A' S- u u re e i- a* c o i— «3 O u CO o re to +J to «3 i« A3 CO o. re s- en o CL o c re re u o to to < O- to QJ to Cv LU Lft O r- CM CM O CNJ CO ro IN( to ■¥■ O CX> r^ co «3" CM CM i— co to o CO o o c re c re p— p— cu ■a < i OJ < CO > re CO > re re >> re cZ i C re to O a: p- a -o c re to o X) i- u to cu +J o to o cu s_ O) en i re -o re i-a re ca -O i- S- to u •r— re C_ oc to re a> to s. 3 O a) u re cc i c o re t_> i >> C O J= •M C o to o cu i- (_> CO to s_ 3 o cu u re ca o N Sm < I c o ■»-> re CJ t c o N re >> re a. i -o c o E re to O cc I o "l-J re i >> c o o SZ M +-> T- C i- < < cu CL O to x: to o. re 3 3: re >> re to +->■ re r— CM CO i— to 3 X) cu to cu CO CO to s» 3 o CJ> CO u re n JD 3 1 S_ J* U c to •r» CO to cn cu -a 4-> •t" cu o p*» to re cu o ^>: J* cu i~" re s. < r- ■ (J) cu re to cu s- £. 3 to CU •p* U c re •p— C£ u_ p- to CM CM CU 3 re > -a cu +j cj cu s- s- o u ,— o o £ • S- — cu +-> -o u c s. (O o to oc o £ cu -o ttJ r— c CD U (O >> c (J o> ro S- I/) on o s_ +J 3 A o o CO s: (_> OJ o to u u ro CT s. c LJ *r" ID O c Q£ o s •f"- •z. o +J CM +J re ^— trt ■M S- a> 1— fO en CO IT) «o- ^ OJ CT> rO ■+J r— ■T"" •^« c (/> « c VO CD -a CSJ s_ c r-» o S- ^~ z o *t- u O) cu JC 10 C <0 LU 4- o> <■ o E C£ ro s_ •^ CD Z C > CsJ s_ o r— o o «*- 1— •r™ -o r— - c m ro to «o- C_) >» cu tfi ■M 4J >> •^ •^ +j to to c c 3 a» <4- O a o <_> O) jd ro (T3 LO LO en LO CM ^— 00 *3" r»- E • • • • LO CO CO LO s- LO o «=r C\J o; r— LO ** ^f > r- o CJ rt3 c cu Q 1) •r— CO CO LO LO a> LO r— CO p-» • • • • CM CO o> r-». O CO r^ CM *3" LO r^. l/l <_ i. 3 |M1 =J f— O o o o u s. a s- a> +J aj +J u e u c (T3 o re o a: i i L_> 1 i <*• i i LO 1 LO Table 5 . Statistical summary of conparison of mean values for density at raceway sites 3 and 4 (see Table 6 and Figure 4) of the Bars tow to Vegas Motorcycle Race. Sites Values Raceway Control I 13.07 26.28 SD .81 4.48 t 4 .09 • DF 1 P ^ .152 <1) a M (T3 CSJ Oi CSJ (O > ^o 0) u • s_ s- c ra 0) o CD •1— c_ +-> J* c o ro s- »+- 2: 4J 0 O M- CO to *r— S- A3 +J 1— a; a) <_} o > E o CD M O U >> 4-> 4-» 3 +-> c to C QJ 5 O s_ 4-> E O 01 co a. s_ *a O (C c C r— m 3 •^ ro 0 -O 4-> C •r— ' •r— •^ M 4-> CO g CO ■r- *- CSJ to a> 0J • o to 4J u a. S- a> a) E 3 T3 to o O (J u to ■ <1J «a UJ *s u un (0 «=r • i. r*. en s_ en a) 4-> 1— 1 m > «T5 ■z. o • CsJ u C 0 # O co h- 0) •f- > +-> « 4-> .,— IT3 > 4-J 0 CC > 0 «— i • 10 tmm * -O «3 cu > o CU > -t-> "a) >) rtJ 3 CU CO o «3- (O OS cr> •z. C^ to cu -t-> to o S- 4-> CO C i— o «_3 r-» 3T r>» OJ u to cc CU u >) JO u 3 i- i. o u -l-> (/> o ^~ J= to to OJ ts> =5 •r— to CO o o> OJ o oo 3 to O o 4J 0) «/l S- s_ o to CO to to «3 to O 4/) o i- -O cu c cu X cu to o to cu i— rji Q- O •«- CU i- r— +■> O < O to to c cu -a > cu c J- CU to •o S- CU -o s_ 4-> CU i_ s- to c s_ re u •«- o s_ c cu n- Q. JO O O o cu u to e 3 S_ Q. CU O > O u o > O > (T3 ai c£ 00 -* u «3 «♦- oo i. o j*i r- u 4-J 13 01 3 S_ to o 4-) i- TO Q. CO CO 1 -C rO -t-> s. a. rO O ^ 4-> j- U -o r— 3 i- S- rC -t-> a. 01 c o ^■4 «3 c; 01 o ro cc > u s» o 4- CO O J^ o «3 •<-> «3 Ol 3 S- i- O +■> CO X! rO 3 cn S- 01 o > CO o x: CO +-> CO 01 3 .^~ 2 X) <_> o o CO 0~> CO cn CSJ co • CO co c\j cn in en ID co cn cn <3- co ro ro rO .a to Z CO to o J3 CL CL rO ra O) 3 Q. -M O rO CO r-* CO cn r— a) •r— 01 ro co •M -t-> i_ •r— 3 u cn C ra O a; en e 3 CO a. < a) C i_ 01 a. *-« s_ •r* ro "O s. •i— i ro 01 oo •f** ro > O S_ 01 o s_ ra i_ a X) f— s- S= •^- ro ^— < 3C -J ro 4-> o s- cu > o V_) > -t-> OS s CU u to in o i. +J tr> VO m ro r— c ^~ r— VO o o CT> ^- CM to z CM CM co o «o ce: CU o >> \ o s- o ■M o JO 2: 3 in 0 to «/) to ct> cu 0) JC •r— > in O 3 CU 0 jo a. 4-> cu t/i s cu 0 a 4-> j= 10 0 s- «3 CQ VO to CO s- < CT» CO O^ ro VO vo in o *s- 1 — 1 — r>« r— «3" Td- r— t— r— VO CO ^ 1— CO *3" VO CM «3- «— (T3 to o E c to u c A3 to to (O 1— 10 o i- a> o '- CO to c cu •o «3 > cu c s- TO cu o to c cu rt3 cu s_ s- e O 1- E cu i- E cu Q. o o o cu JO S- c o •1- •!- to a. cu cu S- o a 3 (O Cl o u cu i/o (O o [Ojiuod eaae }uaq. peoa o CO s>pea} in O uo o CM C\4 »— i— smpajpuni] ul eq/*ON LT> to +-> U oo r>» c n r-. *r~ 00 cn r- f— C o • A ■P" O 00 +J aj re V) •M • o; A a o> LU 0J 0) r— o > C\J cc c r— • ai (0 A .*<: T~ Z A3 E o +j C r— a; 1— to s- 4-> ) 4-> o ■M +J «4- •^ >> c c ■M •^ a> C £ o =J . o O CO .c 0) CJ> r- VI JC cn +-> o r— -C c a. M- •F" A ITS O "O cr> &. i- ,— a» to ro SI £Z . i- +J s_ s- to ■»■■ 01 fO en CO CO z • en puL/jiu aaAco/ea-ie ueaw CM [Cuq.uoo ^^^^^T^^^^ =-*^-:-^ eaae ^uaq. pecu o o o o CO T o o o o — r- o o o o «5- o o m o o C\J o o PL|/2U1 J3A0D 4-> u OJ CO c i. ro *•-+. c c B o 4-> o •^-^ +■> <4- <0 •r» ■o a. ,— c ro z^ R3 U CM i- •1 E > c +J ■ cu c s_ CD 3 0) O • > CU C_3 00 o x: r». u 4-> O en c , r— c ♦+- •^ (O o -a ■1 cu i. CT> E to tO r— cu C ■a +-> S- • c •^ 0) L. fO to CQ <0 ^- ^ ■»-> c n O ro -o i i cu oo c -— ^ CO ro c •> ^ +-> r«» C\J • cr> E c o f— •^ a M oo A S. c CO CU o 01 r— > •^ LU o +J r— • u re CM u ■M C£ CU O) cu o £= en A •r- cu 2T c 3 > O cu o ^~ ^ -c r— *— ro c/1 re •M •I- A J= c Q. to Q. c E +■> re cu (Q u S- S_ U cu cn cu 10 a. •-* e i. ►— H ro re «*- 2 i. CO o 3 +j • in • * [0U3.U0D pecu ll'U'.W.«- ■>-■', H ~ -.Tat" ,. i -i, ,n .,. s>pe-q. >|ue^ C\J o CM — T— IT) T" o u cu to c i. J— % J9A0D re s_ to o *■> <+- u ^— •t— OJ re r— CO i_ re c QJ C_3 re C s- cu M — > C3 4-> a; c C c T- 3 •r~ O ^— *■— *» «_> E a o O * — ■ c i- ■ •f- «+~ <3- -a r- s- ■D en re CU r— c C i- •r— C Qi ^ *"" CO ai "O C +j c re O) re to "O ^-»» M CO re g -co S-. . 0) co u > LT> cu o CT> IS) u r~ * -M c UJ e •r- r- a> CM u C a: i- CD cu ^£ A a. re Z +■> O c r— re CO h- 0) jC E Q. « re a. o> S- E c o> re •r- o o s 4-> o O ^■H .c sz t— t CO Q. 3 3 -C r™» a. re CO re •^ — i- s_ c 0> O) o re +J s- +J re M- re CO o Q- en fe-:,.-^-.. ^gijSgi ^-^>---^ — j^tah a at ----- ■■■■■■■-- ■-- £961 Loaq.uoD 17Z6I esei esjB q.u3} 17Z6I esei pecu nq^m«l^ipm £961 frA^-Vi BaigayhiamSiteMgiwBatta&aBi^ an ivia S>|Dej^ >)UG^ I < 1 I 1 vo uo *r ro c\j !■ I 1' ""I 1 J 1 I 1 I OCTicx)r--<«ouf)«a-mc «3- CD CO CJ r>. 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CD r*. o l/l ro o a) 0) s- s- < <_> *3- r— CO CNI o ro r— CM ro CM cr> CO o ro CNJ O^ CO <3- 00 «3" r— O CXi CO CO o m ro ro en co CNJ «3- ro cnj ro LO i — O f— r— VO ro I— CSJ i— CSJ r— r». O ro ro CO i— CNJ CNJ CO «o- «3- CTi CO CNJ ro ro ro CNJ cr> 00 in CO CNJ «3- ro to O E ro C ro u ro ro to to to o ro .,- QJ ro r— to O i- CD en -* o t/> 3 ro 4= Q. O) O >> o Q. c/> 3 4-> u ro O o c +J (O f— ro 3 f— o o •t— to O r— to ro ro to ro E CD 3 i— C O O O o> c o a» o ro ro c rjj ro CD S- i- ro fO O ro •«- E O •i- 3 to ro to Q. i~ CD Cl o o u E 3 <_> CO o E ro J_ ro C 3 Q. O ro S. CD E O c ro -C a. cd 4-> to CD •> O ro O O) <4- r— • o ■a CO 09 r— S- O) O) Z • > o o • 0) u a. E oo ■«-> to A c cj LU 0) r— u •-H CVI J- »— 1 a> 3 or Q. IS Ml • r~ V) z: 00 CO — o r-s +J c ^— en o o r— 4-> +J t— 0k "O «3 m 0> C a. 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CU fD << to -£» 3 n —j — '. • CU cu CU ^"■n 3 — i 3 rf OJ U2 *< T3 "•■—» o to V O • C — • - ■^. 3 in en to m re c to ft- <-► o to O -j» -5 -h fD 3 cr X Q- r* CO Q. ** — i. fD 3 fD in 3 n 3 1 to fD to ■<• -4* p* e+ «< << - % change + o o CD O O o ro o -A— Hgps^P* • ' '• ■" h'Y m'»iwi t/1 c -5 cr 3 o ft) ro 5^ rtiAwMm .ia» w . m^gpymsa^gm^mm^ irif n.if on ■ ii ro O 1953 1974 1953 1974 1953 1974 1953 .1974 o 1953 1974 1953 1974 O CO o •JU. o o CO c -J r+ — *. — i Q> 3jj c_ -o QJ 3 VO 3 fD _. ro 3 en Oi fD to -s *" O U) — w Q. r+ o -x << — -i C ro r* Q. ai to fD -s 3 1 ro 3 — ^. to D- c+ Oi -5 Q- to v Oi O 3 O ? O 3" to -h VO -h Ol ro Oi 3 *"■*» — >• 42k Q. _i. _i. to ro 3 • fD -*» 3 ro *"■"•' o 3 o rt -s to -s fD o CJ (D O •a. 3 3 -+> 3 o> —A* r+ — <» to C_ to CO << Oi -J. T3 ^*» c+ pt ro -5 3 C *^— * Oi << *5 O CO -s g. to ro QJ cr _*♦ 3 Q. C Oi Q. 3 3 S to 3 BU fD o> f0 O 3 r* O Ol << _,. ro C fD 3 fD 3 - J <"— v 3 — ». n 3 fD < u> rf 3 o -s ro **«— *■ CD r+ < 3 Ol to • 3 fD fD fD — > ro. to 3 -5 a. rt- ^» to -o Oi r+ ail «*^^ -h Ol rt- «< c+ a. -5 cl- ■db V << O 3 ef" o o 3 o- — i. -h 3 >< to o Ol _u t fD to 3 r+ -s -I ro ft) r-f — u y~ -J 3 "O 3" Ol ? ro r+ -5 fD fD ,"- i— i Oi 0* . to << ■o c+ -5 fD fD 3" o — ». fD 3 Oj O Ol O o> r+ -5 r+ 3 3 fD to O T3 *—*• Q. H r+ - % change + O CO CT> O O O 1 i/> c+ C -5 CT 0> 3 o 3 l/> ro w ■ o I ■ O ■ ro o o IT.'"" lUta, in 1953 1974 1953 1974 1953 1974 1953 1974 1953 .1974 1953 1974 o CO o o o to c -s fO ^— « -5 Q. O o << CO —4 fD fD OJ fD fD c • — 1. fD 1 o ft) to -h -5 to fD r* to rt- O DJ to ft) n> << "S —J —J (/) 2 3 3 to —j. ft- rt- g —i. -a en o fD QJ OJ CJ 3 O) Cl Ct- DJ -s ai DJ rl- DJ —J fD o> to O 3 DJ ^b 3 3 Cl *"S ,^, 13 CL a. fD to _, fD O ro O O rt- s: to O »w» -5 o fD s: ^J < w Q. < 2 >—t -=* fD ft) fD 3 i— i -s rt- -5 -5 — i. — i- << Q) 3 o 3 3 O *«~ «« fD a> o 7C -*» H, Cl 3 -a fD -h rt- ■k • -h (/> -^ ■a -j 3 -5 DJ fD QJ o o DJ rt- "* O -5 o 3 rt- — ** fD 7T ft) — — O 3 I/) qj to a> m" 3 3 V) r* fD to — u ^— * — 1. c 1 in rt- OJ GO 3 -s wi* fD O — * •— » O cr a X qj -^ Cl < o> e 3 ■»—•» — i. fD 3 to n ■a > to ta Cl fD fD 3- O ' rt- c fD rt- -5 — >. — »• rt DJ -s o> QJ 3 3 O 3 a- rt- O rt- r* Cl QJ — i. Cl fD fD QJ 3 O s 3 3 3 Z O 3 CD to to a> fD fD ^C —i. -a. -^ fD o- • rt- pt" *< Cl —i. fD ^— «. ^< << c/i —j 3 rt- -o» «# «-*• fD rt S ^^ — i- V) to fD fD • n to 3 fD o o *— ^. to 3 3 -h OS — i. rt- ■ rt- rt- -s «# << 3" o fD 3 % change + o o 03 _9_ en l\5 O ro ro- Li.iLW.tJujiiypi rlS^iii-r u>- ggggg^^s^g^^rr ■■■■ » ^i^M iff rmi V.- fa MS -as r. ■ r - ? % change + o o CO o en o o ro o ro O J5» o en o CO o ow «A 4 P rf c -? ro- cr qj 3 O re 3 — .• LO- ■*'H"J» HMr.'im.-.r— nr- . ■ . irl'-M. , to c -J (0 CJ1 3 (A — > rt- c O r+ cr ■o i^i —J -5 (/> —*• 3- QJ fD rt- CU fD m fD 3 "5 fD o> O C+ O O c fD 3 fD rt- to 3 7T -j. c CD fD fD U) Q. to 3 -I DJ 3 - rf cr 1 —j. r+ -^ n fD DJ to 3 -£» ro o 3 3 r+ c+ O CX» w c to O o fD 3- 3 •«■ fD Z. 3 QJ rt- —j rt rt to 3 "5 to fD *< — i. rt- -J. (O O DJ *»j CL Ml 3 O r+ fD O *>i n- << ,"^> 7T • • s — 1. fD < O o o < fD -5 to ««!• U) 3 fD — ». -h • rt- to to 3 to 3" -s — »• ai DJ _i. — i. fD rt- to rt- 3 -o fD -s o fD 3 n- rt- 3 T3 »< 3" 3 fD "5 m 3 fD C rf fD o DJ 3" to DJ <■+ V) —J —J fD fD -s o C* X 3 -s -s DJ < CO rt- DJ o -s fD ^ -5 fD 3 «< rt- to o £1) 3 O O C_ to o — *. fD c fD — * 3 rt- rt 3 o- a. fD to DJ -s O. *< rt- to fD DJ m*m -J DJ — i. n rt- rt" 3 DJ 3 o 7C fD 3" O O. 3 < l/> (/» CD o fD « • r*" •5 cr — A- 3 a. O fD 3 c fD to to C fD -t> to -a. — i. 3 -j —I. 1 rt- rt- C zz 3 fD fD fD fD o o 3 ^-» Q. fD V) -5 -*i < — >. DJ ro • 3 f+ O LO DJ o o -J 3 12 CO (/) < 1 w DJ 2 C fD fD n <-► fD O- rf -5 3" DJ — 1 fD O -s fD — *. to to £ DJ a. O —a. *»J DJ Q. o — j 3 ^» << -j. -tj -5 O =3 :*r o fD to • (/) to fD O rt- <0 • O -ti -s 1 - % change + o o CO O en o -ft. o ro o ro o o cn o co o -ft* O O *»J -i »*l in rt- C -s EU o rt) ro . rt» =3 U-> . Figure 6: Percent change of perennial vegetation in relation to dis- turbance intensity at raceway sites along the early race course of the Barstow to Vegas motorcycle race of Nov. 30, 1974 as determined from ground (A) and aerial photo (B) measurements of mean density (see tables 6 and 8, Barstow to Vegas race). Disturbance intensity, in order of increased intensity (sites 1-2), is based in part on track frequency at the study sites. TOO 80 60 40- 20- 0) o Ul c (O SZ 20 >« 1 40 60. 80' 100 100 ' 80' 60 ' 40' 20 -— •> -a ai _*. < a. -o ■ 3* 3 3 fD — io fD '*—•' O O) f+ 3- to "1 r+ —j fD -~. ft- n to o << 3 n C fD — »• tO Irt t/) —j -5 3 r+ -i — i. — *. fD o- r+ n> a> to rf O) t/1 •o << C 3 n 3" O t/» o 3" £ tO -h < (D CD QJ 3" w CD 3 -j» a. —j V) _i. to o -5 fD C —J* 3 (D 3* fD 3 fD f+ rf T3 (/> to fD fD O O -s ■^B to 3 -h o fD r+ *■" ^ U) o to ^C —j — *. _», "O c (D 1 3 «-•■ (D -s 3 -h 4s. «< -s Ct" -s •■s— ' O fD ■a o W O o> 3 -5 ■3 3 < <-h 3 o -j. Q. fD tO r+ —j fD -x a> fD to r-h CO fD _ i in fli CJ1 fD •o O t/> -s u> -5 -J ••$ < ^» fD 3 fD fD < a» cu — •. 3 a> to n> 3 3 to p+ fD ^^ ^^ Q. fD (/i .J." ft << Q, Ol o O) ^ o 3 r+ ■-*• VO -ti Q) CD ', 3 ai «»J "1 3 —j O r+ 3 U) o «< 3 O Q. 3 O a> 3 3 _j» d- 3" fD n • Q. 3 3* —^- -s o CD — -i — >. 3 O -5 —J fD ■o o -»l fD n to to Ol -t> — _j £U ■di -s (/» 1 Ol 3 Q. CU 01 r+ -J rh << fD fD n- C O o -s — i. -s DJ O 3 rf ^. < o- O. 3 • "1 ft) fD ai a> —J 3 rt ^« n o —' fD % Change + o o 00 o o in -5 cr o> =3 O ft- ro oj • O o ro O j&a£sii& .•.■■;^-^r-^-t.-i r^tefiraaf hi 3 o — i- o 00 o o o c -5 cd to _l. *—>. -i) — i. fit ™o 2 — t 0 3 r+ CD 1 -j r+ -5 a U> CD -J O ■»— ' a. 3 CD CD T3 CD in O 3 — A. £ 3 !• -5 r* r* — ^° in r+ CD if — ». << fit 0 a 3- rt- ft- 3- -s *< < — fit cd m Oi O 3 a> -a ^—». — 1 3 0 fit □ C fit CD *—*• "1 CD — -* -=» l/l •~~- tn O ~— » n fit -h • V fi* *^+. 3 3 —1 O. -o CL Ql 1 CD cd -c» O -> 3 n — ■ -h CD */» 0 -h 3 n < Oi 1 3 CD -x -T — 1. fi* -J CD. O fit 3 at —j 0. «••■>» cr Q. <: 1 01 m < < CD cd . »— »♦ CD CD US -s a. 3" CD << O «d> cl- 3 0 O ot 0. 3 ^— rf n> c* CD _u 3 3" mto O en Q 3 C 3 CD O cn m 1 CD — >. 3 -s CD 3 O 0 fit tn c* e (/» -j. -J O 3 CD rf CD -S Q. a. CD —j O (/> fit «< 2 < r+ O Cu CD — a. _a« —* *< '-Q 3 O CD CD 3 ro ft- C_l r+ — * fi) fit r* -s w r+ z. O a* -^* a" — *> — I O 0 Q. — * 10 3 3 -_. in «-J CD tn OD a. r* -5 CD O 1 CD 0 3 Ql C in 3 C 3 cr ■a r* *< ot CD Cu •afc O 3 O O 3 0 «■* 3" 3 • CD ■^a. «t. < — > 3 _j. CD — • CD O 3 —* m fit Mia c+ *< a»M (/) tn CD 0. C e* 3 a* CD -s c tn 3 V) CD -5 —~ a. Q. zr o> 3 n CD i - % Change + o o CD o o^ o o o PO O O 1 O 00 O O O '?S&i£g£&V to c -5 cr 3 n ro j&gs&g&f-ifcf. 3 ^8lBj#!ri;ji^g^^!^*^k^,v^ c * -h —j r+ —i ^— » c r+ -o o -5 o> -5 UD —^ m e- fD —4. O -5 QJ in i fD -^ -s U) 3 ia 3 ro CD o- o r* fD in •~» » m QJ fD c n- fD OJ —i. 3 3 -5 3* -a o 3 QJ <-f o ft- o- fD — . r-t- Q. "S fD fD O) pi- to fD O 3 o ^J — i. _ >. 3" o fD ai ■o VO o- 3 3 a> n> 3 -s ^j ^J QJ r+ 3 <->■ fD a> "xj m C- fD O _*. fD a> o fD O 3 fD 3 -5 fD in a. =r in f+ <-t- Q. fD 3 — i. O cd O o -5 o m rt- -h 3 -h O) —u 3 O << m 3 r-t- fD 3 X3 — «• o» fD m O QJ fD r+ EU -? o < <-f -s "< "D m Ql QJ 3 QJ fD «^» c 3 fD ■a —t at 3 < n- -s Q. -x QJ —J 3 0> fD O — i. -s fD -s _u —J QJ 3 a> QJ << fD QJ c -* a> — < r+ M o — < fD fD m a. —i. -5 in QJ in fD ■a < O fD < c lO 3" fD a> fD a O 3 -5 O m rt ia O C fD fD r-t- 3 e-t- — »» fD O. r+ a. fD O fD C o ri- —4. s m IQ QJ -s 3 al -t» 01 Q. -5 in o- QJ rt- —J. -s fD -h a> C QJ — ^ — . fD a. n -5 ■a -s 3 o CL • -s O 3" fD n QJ 3 10 fD Bl 3 in 3 fD fD 3 O. ., in m r-t- C 3 — i. 3 fD fD 3" in r+ 3 O fD fD — i • in rt rti "5 C 3 fD -*» fD fD m O O O 3 1 -J X fD fD -H in -s a* -a 3 -X — >. o rt — _o* c+ a> a. rt- Qj — -. Oi 3 fD a. fD *< a. o 3 r+ -s _dU 3 3 Ot fD QJ l/> < < rt- 3 o r-t- ^» QJ fD rt- — .. 1/) -h — i. rt —j 3" O o — .- * 3 ^< C _i. 3 <-(■ a> ia fD O a. << -h in —j — *. Q» ■3 fD m O" o i o 3 < fD - % Change + O CO o o ro . OJ • c -5 cr D) 3 3 -.. en CTv *»J - CO CTi O o o _JL_ V2 M % 1 O — u -&. en o o I f CO o o o Figure 11. Percent change of perennial vegetation in relation to time use intensity values at a raceway site of the El Cajon Motorcycle Race held Dec. 3, 1972 in the Yuha Desert near Plaster City, California determined from analysis of density from aerial photographs. Disturbance intensity value 1 represents change of vegetation at the site between the years 1953 and 1972 with no race. Value 2 represents change during the race (between the dates of Nov. 26, 1972 and Dec. 12, 1972) at the same site. 100 ■ 80- 60- 40- + 20- £? 0 m *« 20- H 40- 60- - 80- 100- ^^ 1 2 Disturbance intensity ro —i. <**• — < o r+ -o 3 3 <£> — i. c fD n» rt- en rt- -5 -5 fD CD u> << O" O 3 3 V a> fD (/) OO CU 3 3 ^» ^. 3 o r> rt- rt" <-► a. Cu ro << << —» O —j —i. •*• 3" a> < vo -h 3 o> rt CU ■>vj O rt" 3 —1 ro -s fD (O rt e 3 3 fD zr fD 00 _^. OO a> 00 fD O) — 1. O -5 rt- -h -a "»"■>» •k CD «< ^ ^ fD oo •a rl- 1 oo CU fD Q. rt" -j fl) •>— «» a> fD fD -5 fD r-t- -S 3 fD -5 -5 fD fD 3 CU fD — ». '3 O _*. oo -a Q) ^ -J CU -5 -^ — i* fD —j -^. fD 3 CU a 00 TJ fD rt" < fD 3" CL -j. fD o 3 O O IQ -5 rt- rt- -h 3 fD C- O -S rt" ro o O -h fD 3" 3 cu 3 3 00 O) -5 OT^h rt • ■^ fD _^* 2 << CU 3 o o oo OO -5 cr O —i. "1 fD oo — ». 00 3 fD a< fD 00 fD to -5 rt" o Cu CU «rf. < c rt> -s r+ 3 fD -5 _i. UD CL o- a. -o O o> fD —J 3 ^. c 3 3 CU 3 00 n 00 00 r+ rt- fD fD — J- <-»■ O CD rt" fD 3 << -5 a. oo ■a ^is -h in rt -5 i << o % Change + O 00 o o no « u> o to r* c -s cr O) 3 O 3 r+ CD 3 m c-t- << Cn CO en O o no o /> ^% ro o o en o oo o o o I I 1 € to c -s Ui —J QJ £ Q. cr _j. -o 1 3 Cu ■■»■ 01 3 fD o O. *< V) 3 r+ -5 II r* n fD n ■~J CU lO C fD 3 fD tn -t» r+ -5 (/> 3 03 c+ C CT _i. c+ 00 fD Q. a> 3 r+ ** • -5 «< 3 o fD *< O 3" ro "~*- "O fD 3 CU CU i O — i V) c+ 3 O ft) O _j. —J. (O ii n rf 3 r+ «■+ fD -* • C/> r* << 3" "■■* fD fD O — J — j O 3 < -♦> —^ r\3 2 ui CU m w • V — ». —j —j -a cu c+ C fD U> — ^ ft) << fD o -5 i VO -s V) CM fD o ■»>J —I. s C_u 3 11 cr> Cu «•— N O 3 VO »— * — ' <-*■ — < 3 _j. cr> 3* ■ 1 cu o r* ■a U> 2 • 3" 3" Q. «_^ o fD O fD r* < rt O Cu o fD m O -s -s -s to ^^ o fD fD o fD -s a << r+ o O) t/> cr o CU Cu T3 fD 01 <-»• C_i. =r C 10 fD o co fD o 3 ft" Q. fD a. "S O) 3 50 Cu 3 o o _j» Cu 7^- CO 3 fD 3 O fl> -j. n> 3 r+ cu O "J o- *< 3 -h fD fD <~» O o CU o -*> a CT fD ft- •■■• O ■^m.-* (/> n *"J fD o (-»■ fD s -5 3 C — '• < u> -5 ^~ ^ r+ fD VJ r+ O" 3 3" a. o CU O .•t. _, 3 < 3 _i. VO a. O • 3 ^J Mia fD ~h n r\s CO ro o -5 . rh < cr> c fD C CU w "S o> -? — ' to o O" C — j -J fD cu fD VO 01 to 3 l/l *^J o <-t- o ro fD 1 c -J 1 fD C lOOi 80 60 4(T 20- 0- 20 40- 60- 80- 100-- 1 2 3 Disturbance intensity Figure 14. Percent change of perennial vegetation in relation to distur- bance intensity at recreational and off-road vehicle use sites in Afton Canyon, 61 Km northeast of Barstow, California. Dis- turbance intensity values represent, in order vof increased use intensity, vegetation denution. Hillside trails consisted of denuded strips (1) while pit areas (2) had large expanses of.. nearly complete denution. Ground measurements taken May 15, 1978. Percent change values determined from measurements of density (D) and cover (H). c o IUU' 80' 60- 40 ■ 20 0 ; 4 U-= -1 • i { 1 - i 20 j V I 1 - J 40 * ■'x ; i 60 > r" C 1 t \ 1 V 80 • ! 10Q ' i Disturbance intensity Figure 15. Percent change of perennial vegetation in relation to distur- bance intensity in recreational and off-road vehicle use sites at Stoddard Valley as determined from ground measurements taken May 14 and 28, 1978. Disturbance intensity values (1-4) represent, in order of increasing use intensity, progressive denution of vegetation at study sites:' 1-hillside trails; 2-raceway; 3-pit area in creosote bush scrub; 4-pit area in alkali sink. Percent change values based on density (D j and cover (a). - % chanae + o o CO o en o o ro o ro o -Cfe o o CD o o o r+ c or a> 3 O ft) 3 ro- u>- JS». tfkmm smOHm iimr iw i h imf k1"'^" -Jl *"■' g - 4--^, Figure 16. Percent change of perennial vegetation in relation to disturbance intensity at the Kelso sand dunes as determined from comparisons of aerial photographs taken before (Apr. 15, 1953) and after (June 9, 1974) use by recreational vehicles. ^Disturbance in- tensity values (1-3) represent progressive increase in use in- tensity from the vehicle hill runs of the fore dunes (□) to the pit area and trails of the desert floor (0) at three sites along the edge of the dunes. Percent change values determined from measurements of density. . . 1001 80. GO- 40' 20. + en c 5 20H ' 40- 60- 80- 100- WW 2 3 Disturbance intensity io c •■fcj in fD Q» — j. ~Q 3 C m m 3 fD s: 3 rt- rt- 1 a fD 01 Ol fD O s O. cr fD 3 fD Q. — < rt in 3 • — i. fD —j. rt — J» in "S rt 3 3" 3 << O "O n 3 3* fD -5 fD 3 •■i* Ql -s fD 3 fD 3 3 n 01 rt a. IQ a> in • o> fD 3 -a. -*i rt- 3 •% —j — i. IQ O o fl> 3 O 3 -s sr in ID ■a 01 Q. rt O) fD fD 3 —*. c fD -5 (jQ in 1 -s -J fD CD rt cr — «. fD 3 c Ol Ol O 3 < -? 3 i_J -. —j. a» cr O fD Ol ^^ Ql fD ■a oi ^J c 3 3- rt- fD O — ». o — 1. < m fD 3 rt- o CD rt- O 3 CO o -h fD O o> CD a> -x 3 -J — * rt- ^^ o m OJ Oi o 3 ■■J* "O < rt- c rt- 3" fD —. ■^ rt V; m 3" o en 3- ■»(• 3 rt- (D < O" o fD a. fD —J ab Q. ■a —> -h fD 3 fD c o -h "5 fD -5 ■a -i -s mI» in fD ■*!■ CD o "O rt- — < 3 3" o— ^ «— ^ Ol fD — . a —j Ol rt Q. -s 1 ID 1 _i. fD << cn cn fD O 3 ^— ' CO a> 3 in o -~_-- •j* -h -5 o rt- rt- fD o> -h O << r+ "O 3 3* -5 a. c a. -h fD * fD o ■ala ■ji m 01 jy in UD "O fD -h 3 rt C — i. 3 rt m c -J rt- rt- fD O "J fD -s 3 cr CO 01 •a Ol • -s -s .—^ < 3 fD fD ^j Ol r> a> 1 no fD fD I r+ ro 3 to - % Change + o o 03 o en o O ro o ro o o o CD o o o w, 1 ro U/. m to c+ c -S cr 0) 3 U> o ro -e» . en CTi Figure 18. Summary of mean percent change of perennial vegetation in relation to disturbance intensity for study areas 1-7. Disturbance intensity values 1-3, arranged in order of increasing intensity, are based on. area summary use intensity types (Table 1, ABC, conclusions). Disturbance intensity value 1 = B, 2 = C, 3 = A. 100 80 * 60 * 40 - 20- en c u 0 20 - 40 - 60 - 80 - 100 1 2 3 Disturbance intensity BIBLIOGRAPHY Arndt, W. 1966. The effect of traffic compaction on a number of soil properties J. Agricultural Engineering Res. 11:182-187. Berry, K.H. ed. 1973. Preliminary studies on the effects of off-road vehicles on the northwestern Mojave Desert. Privately published, Ridgecrest, Ca. p. 100. k Berry K. ed. 1977. Proceedings of the symposium on the physical, biological, and recreational impacts of off-road vehicles on the California Desert. So. Calif. Acad. Scis. Spec. Pub. (Unpublished) . Broadbent, S. 1974. Scavengenes on wheel. Sierra Club Bulletin. Brower, J.E. and J.H. Zar. 1977. Field and laboratory methods for general ecology. Wm. C. Brown Co., Dubuque, Ioqa. 194. Bureau of Land Management. 1970. Summary of the off -road vehicle advisory council report. Pamphlet by the US. Dept. of the Interior. Bureau of Land Manage- ment. Bureau of Land Management. 1970. The California Desert; a critical environmental challenge. US Department of the Interior. 3ureau of Land Management. Bureau of Land Management. 1973. Environmental analysis record for the interim critical management program for off-road vehicle use of the California desert. US Department of the Interior. Bureau of Land Management. Bureau of Land Management. 1973. Evaluations and recommendations El Cajon Valley motorcycle club's unauthorized race — Feb., 1973. US Department of the Interior. Bureau of Land Management. Bureau of Land Management. 1974. Environmental assessment, Barstow-Vegas motorcycle race August, 1974. US Department bf the Interior, Bureau of Land Management. Bureau of Land Management. 1975. Evaluation report, 1974. Barstow-Las Vegas motorcycle race — March, 1975. US Department of the Interior. Bureau of Land Management. Bureau of Land Management. 1974. Final Environmental impact statement, proposed Barstow-Las Vegas, motorcycle race. US Department of the Interior. Bureau of Land Management. Carter, L.J. Off-Road vehicles: a compromise plan for the California Desert. Science 183(4123) :396-9. Davidson, E. , and M. Fox. 1974. Effects of off-road motorcycle activity on Mojave Desert vegetation and soil. Madrono 22:381-390. Duck, T.A. 1976. The effects of off-road vehicles on desert flora, in Abstracts, So. Cal . Acad. Scis., Ann Mtg., Santa Barbara, Ca., 44. Duck, T.A. 1977. The effects of off-road vehicles on vegetation in Dove Springs Canyon, in Berry, K. (ed.). Proc. of the symposium on the physical, biological, and recreational impacts of off-road vehicles on the California desert. So. Calif. Acad. Scis., Spec. Pub. (unpub.) Hadley, R.F. and C.T. Snyder. 1975. Environmental impacts of off-road vehicles in arid areas. Geol . Soc. America Abs. Prog. 7:1095. Harrison, R. 1976. Environmental effects of off-road vehicles. Engineering tech. information system. US Department of Agriculture. 4-8. Hicks, D., A. Sanders, and A. Coopeerrider. 1976. Impacts of Barstow-Las Vegas motorcycle race on wildlife habitat. Bureau of Land Management Unpubl . Rept. 46. Johnson, H.B. 1976. Vegetation and plant communities of Southern California Deserts-a functional view, in J. Latting (ed.). Symposium proceedings plant communities of Southern California. California Native Plant Society Spec. Pub! . no. 2 Riverside, California. 125-162. Johnson, S. 1974. Rv/II:The new generation of recreational vehicles. Sierra club bulletin. Keefe, J,, and K. Berry. 1973. Effects of off -road vehicles on desert Shrubs at Dove Springs Canyon, in K. Berry, (ed.). Preliminary studies on the effects of off-road vehicles on the northwestern Mojave Desert. A collection of papers. Privately published, Ridgecrest, California, pp. 19-44. Luckenbach, R.A. 1975. What the ORVs are doing to the desert. Fremontia 2:3-11. Larson, F.R. 1971. A comparison of aerial photo and ground measurements of Ponderosa pine stands. USDA Forest Service Research Note RM 192. Los Angeles Times. Dec. 17, 1974. Battle for the Great Mojave. Murchie, D.R. 1973. What trackless desert. Sierra Club Bulletin. Office of Library Services. 1973. Environmental effects of off -road vehciles. A review of the literature. US Department of the Interior. Office of Library Services, Bibliography series #29. ORV Monitor. 1974. ORVs and the California Desert. A Case Study. Press-Enterprise. 1978. Wilderness: The Coming Stuggle. Snyder, CT., DG. Frickel , RE. Hadley, and RF. Miller. 1976. Effects of off-road vehicle use on the hydrology and landscape of arid environments in Central and Southern California. US Geological Survey Water-Resources Investigations 76-99:45. Stebbins, R.C. 1974. Off -road vehicles and the fragile desert. Amer. Biol. Teacher. 36:203-208, 294-304. Thorne, R. F. 1976. The Vascular plant communities of California, pp. 1-31. _In_ J. Latting (ed.), Symposium proceedings plant communities of Southern California. California Native Plant Society Spec. Publ_. no. 2, Riverside, Calif. Turner, R. B., A. T. Vollmer, B. G. Maza, and P. A. Medica. 1976. Effects of off-road vehicles on a creosote-bush community in Southern Nevada. _IH Abstracts, So. Cal . Acad. Scis., Ann. Mtg., Santa Barbara, Ca., p. 45. Vollmer, A. T. , B. G. Maza, P. A. Medica, F. B. Turner, and S. A. Bamberg. 1976. The impact of off-road vehicles on a desert ecosystem. Environmental Management. 1(2) : 115-129. Webb, R. H. 1977. The effects of off -road vehicles on desert soil in Dove Springs Canyon. Jjl Berry, K. (ed.), Proc. of the Symposium on the physical, biological, and recreational impacts of off-road vehicles on the California desert. So. Calif. Acad. Scis., Spec. Pub. (unpubl.) Webb, R. H., and H. G. Wilshire. 1977. A Bioliography on the Effects of Off -road Vehicles on the Environment. 12p. Wilshire, H. G. 1977. Study results of 9 sites used by off-road vehicles that illustrate land modifications. US Geological Survey Open-file Rept. 77-601:19. Wil shire, HG., and JK. Nakata. 1976. Off-road vehicle effects on California's Mojave Desert. Calif. Geology. 29:123-132. Wil shire, HG. , and JK. Nakata. 1977. Erosion of off-road vehicle sites in southern California, in Berry, K. (ed.). Proc. of the symposium on the physical, biological, and recreational impacts of off-road vehicles on the California desert. So. Calif. Acad. Scis., Spec. Pub. (unpubl.) Related Articles Johnson, H. B., F. C. Vasek and T. Yo.nkers. 1975. Productivity, Diversity and Stability Relationships in Mojave Desert Roadside Vegetation. Departmei of Biology, University of California, Riverside, CA. Bulletin of the Torrey Botanical Club. 102(3) :106-115. Sharp, R. P. Kelso Dunes, Mohave Desert, CA. Geo. Soc. of Amer. Bull. V. 77, p. 1045-1074. 19 Figs. Pis. Oct. 1966. Vasek, F. C. , H. B. Johnson and G. D. Brum. 1975. Effects of power transmission lines on vegetation of the Mojave Desert. Madrono 23(3): 114-130. HERN CALIFORNIA ACADEMY OF SCIENCES 9QQ EXPOSITION BOULEVARD ■ LOS ANGELES, CALIFORNIA 9GQ07 June 20, 1978 Dear Professor Lathrop: Regret fully, we find that we shall be unable to complete publication of the symposium papers which you ordered some time ago (the proceedings of our 1976 symposium on "The Physical, Biological, and Social Impacts of Off -Road Vehicles on the California Desert"). Consequently, we are enclosing our refund of your payment. Thank you for your patience; we are truly sorry not to be able to fill your order. Should the papers become available at some later date we will let you know, in case you might wish to re-order at that time. JSH:3 Enc: chk #3086 - S5.C0 Sincerely, Joseph] Z. Haring, ^^D. Treasurer APPENDIX A Plant Specimen List Plant Response Parameters to RV and ORV in the CDCA Aizoaceae Mollugo cerviana (L.) Ser. Asteraceae Acamptopappus sphaerocephalus (Harv. & Gray) Gray Ambrosia dumosa (Gray) Payne Baileya pauciradiata Harv. & Gray Bebbia juncea (Benth) Greene Brickell ia incana Gray Dyssodia cooperi Gray Dyssodia toerberi (Gray) Nels. Encelia farinosa Gray ex Torr. Encelia virginensis A. Nels. Erigeron pumilus Nutt. ssp. concinnoides Crong. Eriophyllum wal lacei Gray Gutierrezia microcephala (DC.) Gray Geraea canescens T. & G. Haplopappus acradenius (Greene) Blake Haplopappus cooperi (Gray) Hall Hymenoclea salsola T. & G. Lepidospartum squamatum (Gray) Gray Machaeranthera tortifolia (Gray) Crong. & Keck. Palafoxia 1 inearis (cav.) Lag Pectis papposa Harv. & Gray ex Gray Stephanomeria pauciflora (Torr.) Nutt Agavaceae Yucca shidigera Roege ex Ortigies Tetradymia stegrelepis Greene ( \ Bignoniaceae — Chilopsis linearis (Cav.) Sweet Desert mallow Boraginaceae v Coldenia palmeri Gray Coldenia plicata (Torr.) Cov. Brassicaceae Lep/dium fremonti i Wats Cactaceae Echinocactus polycephalus Engelm & Bigel Opuntia basilar is Engelm & Bigel Opuntia echinocarpa Engelm & Bigel Opuntia ramossima Engelm Capparaceae Cleomella obtusifolia Torr. & Frem I somen's arborea Nutt. var. arborea (Cleome isomeris Greene) Chenopodiaceae Atriplex canescens (Pursh) Nutt y A triplex hjdnenelytra (Torr.) Wats Atriplex ploycarpa (Torr.) Wats Ceratoides lanatum (Tursh) T. Howell Grayi/ spinosa (Hook) Mog. Ephedraceae Ephedra nevadensis Wats . Euphorbiaceae 0 a. * Croton cal ifornicus Muell -Arg Fabaceae Acaccia greggii Gray Cassia armata Wats . Cercidium floridum (Benth) Wats. Benth. Dalea cal ifornica Wats. Dalea emoryi Gray Prosopis glandulosa Torr. var. torreyana (L. Benson) M.C. Jtn Lamiaceae Salvia columbariae Benth. Salvia dorii (Kell.) Abrams Salazaria mexicana Torr. Lennoaceae Phol isma arenarium Nutt. ex Hook. Loasaceae Petalonyx thurberi G. Malvaceae Eremalche rotundifol ia (Gray) Greene Nyctaginaceae Mi rab ilis froebel ii (behr.) Greene Papaveraceae Argemone corymbosa Greene. Plantaginaceae Plantago arista ta Michx. Poaceae Afifrstida fendleriana Steude Bouteloua barbata Lag Bouteloua eriopoda (Torr.) Torr. Erioneuron pilosum (Buck!) Nash Hi 1 aria jamesii (Thurb.) Benth. ex Scribn. Hi 1 aria rigida (Thurb.) Benth. ex Scribn. r Muhlenbergia pojzteri Scribn. Oryzopsis hfrmenoides (R.&.S.) Ricker Tridens muticus (Torr.) Nash Polygonaceae Eriogonum fasciculatum Benth Eriogonum heeryrmannii Dur. & Hilg. Eriogonum inf latum Torr. & Frem. Rosaceae Coleogyne ramosissima Torr. Fallugia paradaxa (D. Dom) End! Prunus fasciculata (Torr.) Gray Solanaceae Datura meteloides A . DC . Lye i urn cooperi Gray Zygophyllaceae Larrea tridentata (sesse & Ntoc ex DC.) Cov APPENDIX B 1. Calculations d = Idi/rn A = d2 TD = u/A RD. = r^/in Di » (r\./tr\) (u/A) Fi = Ji/K Rf. = F./If Ci = (a.) (D.)/n. RC = C./SC IV = RD. + Rf. + RC t = t^^TFT Sa sx = -v /n ID. = ni/L ICi = li/L Rci = li/Zl APPENDIX B 2. Symbols TD = total density Di - density of individual species u = unit area A = mean area per plant2 RD ■ relative density ni ■ is the number of individual of species i s species Zn - total no. of individuals of all species measured f. = frequency of species i ji = no. of sampling pts. at which species i was counted k ■ total no. pts/plots samples RF - rel . f req . Ci = coverage for species i ai = sum of foil age coverages IV = Imp. value = RDi +■ RFi + RC. di = point to plant distance for individual i 3 ■ mean pt. to plant distance Zdi = sum of individual pt. to plant distances d2 = mean pt. to plant distance square d = sum of d. t = t statistic evaluation (paired observations) D.F. = degrees of freedom x = mean SD = standard deviation APPENDIX B II Symbols (con't) sx = standard error of the mean li = sum of intercept lenghts for species i L ■ total lenght of all transect sampled El = sum of intercept lengths for all species Ic. = linear coverage index ID. - linear density index RC ■ relative cover RC. = relative cover for species i I - sum APPENDIX C Plant community classifications for the CDCA Thorne (1976) Creosote bush scrub Alkaline scrub (alkali sink) Desert dune Sandplant Blackbush scrub Johnson (1976) Cheesebush scrub APPENDIX D Study Areas Area 1 "Uawbone Canyon: 19 miles NNE Mojave, Kern County, California 5 miles W Hwy. 14 T 30S, R37E, Sees. 19,20 T 30S, R36E, Sees. 20,21,22,23,24,27,28 k T 29S, R36E, Sec. 14. -^ttove Springs: 24 miles NNE Mojave 11 mi els W of Hwy. 14 T 29S, R37E, Sees, 5,6,7,8,9,16 T 29S, R36E, Sees. 1,2 T 28S, R36E, Sees. 31,32,33,34,35 Si Area 2 Stoddard Valley: 5 miles SW Barstow, San Bernardino County, California 1-3 miles SSE of 1-15 T 9N, R2W, Sees. 26,27,35,36 A Area 3 Johnson Valley 14 miles E Lucerne Valley on -Hwy 247 N 6 miles beyond Soggy Dry Lake, San Bernardino County, California T 5N, R3E, Sees. 28,27,21,22 Area 4 *^A. Afton Canyon 38 miles NE Barstow, San Bernardino County, California 4.5 miles ESE 1-15 T ION, R5E, Sees. 17,18 vB. Kelso Dunes 12 miles SSW Kelso, San Bernardino County, California T ION, R12E, Sees, 3,9,10 Area 5 Plaster City: ^a. Pit area no. 1 3.5 miles E Plaster City, Imperial County, California 60 a . AREA • =6./+3ha 25^ m PLAKT RESPONSE PARAMETERS - RV and ORV in CDCA, Ca, Aerial Fhotograph Calibration Data Dove Springs ite: IO-15-52 Photo size: K'3. ABL-6K-l87-l89f ABL- 29-32 9x9 1 2o,coo *sirent Grid Measurements On Ground Equivalent Measurements 123^5 1 1 _u •lo en each side of sa« aqs« t 1.9 cm -2.95 cm rea of sa i ha 3qs. I I 1 ' ' r H ' H 2o tn ea side of sm sqs. AREA = 22, M2 la ■ 590 m 380 bb • 2^ cm £*t 5 cm ^ ^ .2 cm A -1.65 cm-^f W D 500 o & 330 n 1 cm 1.27 ■■1.27 cm 20p m ,>60 o . AREA ;=6.^5ha 25<+ m 25^ m PLANT RESPONSE PARAMETERS - RV and CRV in CDCA, Ca. Aerial Photograph Calibration Data AREA: | Dove Springs • Photo Date: 5.27-73 Photo size: 9x9 Photo Kos. 9-44 1000 BLM CM000 -2 12- 537-539 RATIO: 1:20,000 Transparent Grid Measurements On Ground Ecuivalent Measurements 12345 a \\y\ b m c " .lo ca each side d of sn. ac^s • t 1,9 ca -2.95 cm rea of = .ok ea side sa ' ha of sm 1111 Lr y p H 2o a sqs. AREA = 22. 42 ha ■ ' 590 m 380o .24 cm <• 5 cm -^ .2 cm ^ -< 1 » *< l.o? cm -7* 48 40 o 500 a » 40 a 330 a L < 1 cm 1 cm- /♦ • • k .3 cm! V If V. 1.27 200 a ,>60 a . AREA •=6.45ha 254 □ . • PLANT RESrCuSS PARAMETERS - RV and CRV in- CDCA, Ca, Aerial rhoto^ranh Calibration Data Dve Springs aer- -2-19-73 Photo size: 9x9" ••c CM000-2-12-271-275, CM000-2-11-195, 196 120,000 - - - ___:._ _ _ -•- sprent Grid Measurements . :_ On Ground Equivalent Measurements -. - ,125^ each aqs. side U.IT ^ .lo CO of sm. 1«9 cm -2.95 cm I EI __ Area of sm 3cs. i - mok ha 2o mvea side of sm sqs. AREA = 22. kZ ha 590 m 380 ,2k ca k •4-H+ ^- — 2.5 cm j- • 2 cm A «— l.t>5 cm-?-1 PH+ o 500 m \0 m DH-rW- 330 m 1 cm CE ' • .3 cm ^ 1.27 1> •1.2V cm 200 n ,>60 a . AREA ~ ' =6.if5ha 25^ n 25^ n Area 2 Stoddard Valley PLANT RESPONSE PARAMETERS - RV and CRV in CDCA, Ca. Aerial Photograph Calibration Data Stoddard Valley • Dae: 2-27-53 He. AXL-49K-151, 152 Photo size: 9x9" 120,000 isjrent Grid Measurements On Ground Equivalent Measurements 12 3^5 1 V TTT I b c i •lo cm each side of sn. aqs. -ir-2.95 cm -*■ t 1.9 cm I , , ... Area of sn ^cs. rcn: = .o4 ha 2o o ea side of sm sqs, AREA = 22 A2 ha 590 m 380 m *2k cm X 3 cm • 2 cm * l.o;? cm-^?-1 W Q DH+A- 500 m ^0 o 330 o 1 cm c<1 . . . V it .3 cd 1.27 I • 1.27 cm 200 o ■7~frr ^>60 o . AREA 25^ Q 25^+ a r Area 3 Johnson Valley PLANT RESPCJJSE PARAMETERS - RV and CRV in CCCA, Ca. Aerial rhotocranh Calibration Data h . Johnson Valley I : 11-26-52 AXL-16K-41-47 Photo size: 9x9" :0,000 :s3;-ent Grid Measurements On Ground Ecuivalent Measurements 123^5 , 1 LI L • .lo ca each side Of S.m. SC3. 1 1.9 en -2.95 cm I Area of sm 5qs. Ilir- = ,c4 ha 2o in ea side of sm sqs. AREA = 22.^2 ha 590 m 380 a ,2k cm 444 *t 5 cm 5- •2 cm \ 1.05 cn^» DK m 500 m D*4 kQ a 330 o 1 cm ■:; 7'. . . v '• .J en • t 3 f s 1.27 .-27 en 25<+ a 25*t_ia Aerial rhoto^rarh Calibration Data -.REA: 3. Johnson Valley c Photo Date: 5-28-77 Photo size: 9x9" Photo Nos. BLMCA 93-77 6-10-14 BLM CA 93-77 5-11 BLMCA 93-77-6-11-15 JATIO: 1:34,800 Transparent Grid Measurements a b c d '1 2 3 4 5 8 JJ -Li • lo cm each side of sou aqs. t 1.9 cm -2#95 ca ( Cn Ground Ecuivalent .Measurements ■ r t py. Area of sa sas, = .12 ha 34.8 a ea. side of sm. sqs. AREA =67.8 ha lo26.6 m 66l.< .24 cm V£- 2.3 cc ■T » • 2 ca A •1.53 cm-t' 83.5 m. 69.6 a 1 ca 1.27 4; 1.2? ca 3^8 m ' AR£A= • IS. 64 « r.a 431. ^ B 431.8 a Area 4 Afton Canyon Kelsa Dunes i I'u^u.isia.jn vax^ui. ^^i.w:i u>^<*> c N *lo cm each side 1.9 cm d of sm. aqs* Jr -2.95 cm I Area of sa 3qs, ' = «o*f ha 2o m ea side of sra sqsv. AREA = 22A2 ha 590 m 3& .2^ cm hum w+ d»3 cm ■*■ (X .2 cm * i -^ Lop cm-f1 1 cm TT 1 cm I J , . . V '• .3 cm . . * V * 1.27 ,1 -1.27 cm 200^ a ,>60 a . AHSA ;=6.^5ha 25^+ a 25<+ a PLANT RESFCtJSS PARAMETERS - RV and CRV in CDCA, Ca. Aerial Photograph Calibration Data so Dunes ___ l's: ? 2-8-76 Photo size: 9x9 r. U-2 photo UAG 1045, 153.22-1278, 2877, 2876 I- .20, OOO :arent Grid Measurements On Ground Eauivaient Measurements. 123^5 a IM I II b I •lo cm each side of sm. aqs« 1,9 cm W-W •2 cm A 4 1.05 cm-^H 288 m +4h 3000 m 240 m &+&W^ — \ 1 cm vr: . . . \ 3 cm t 1.2? I •1.2? cm 1200 m ^>3o0 m •AREA = ;232.2ha 1524 m 1524 m Aerial Fhotograph Calibration Data fl: 4. Kelso Dunes hotc Date: 4-14-53 Photo size: 9x9" hoto Nos. 1046 CS3720 GS-VP 1-60, 61, 1010 CS 3720 GSYP 1-1,2 ATT.0: l;47,2CO Transparent Grid Measurements On Ground Equivalent Measurements 123^5 Th a ■'™r. JLL c r d 1 i i L ■ •lo cm each side of sm. aqs. 1.9 cm -2,95 cm .2 cm DiVi'i \\> — T2 [ ^«£ — ■ — l.o5 cm-?1 1 cm 1/ ... v i =4 : -3 cr- t 1.27 y 'K 1.27 ;.-.". )f sm ha . side sqs. of I"T I II r Area c R 47.2 a ea. sm* sqs. 8# 1392.4 a ^ •AREA= '35-9 ha 599.4 5$9.4 PLANT RESFCI.'SE PARAMETERS - RV and ORV in CDC A, Ca« Aerial Fhotograph Calibration Data X'. Kelso Dunes as: Oct. 9, 1954 Photo size: 18 x 18" o. VVFS-M60 AMS 145-4593-4597 :^3,2co rsprent Grid Measurements • 123^5 urn .lo cm each side of sm. aqs. f 1.9 cm -2.95 cm On, Ground Ecuivalent Measurements f _ Area of sm sqs. ±L^ v = .18 ha W5.2. m ea. side of sm. sqs. AREA = lQJf.6 ha 127^ B 820.8 D iZk cm 5 en • 2 cm A «-^— -I.65 era-?- «■ 103. 6 o 4+i lOcO ra $6 A m »fo 712>a B 1 1 cm n tt-n > . . . v /• .3 cm J ^ 1.27 I 4^ 1.2/ Cfl] ^ 32m ~7 \ rf>129»omr wVR£A= ; 30 ha 5^8.6 m 5^8.6 m Aerial Fhotocranh Calibration Data lIZA; ih Kelso Ounes hoto Date: 6-9-74 Photo _size: 9 x 9" fysTtf isTos. BLM-C-M000 12-58-60 w fflXQ: 1:20, COO Transparent Grid Measurements On Ground Equivalent Measurements 123^5 a. b c d CO each side UJ 1,1 L R .10 of : sm. aqs. — , t 1.9 cm -2.S5 ca I -t-t^te Area of _ sra 5qs. = .0^ ha 2o m ea side of sin sqs* AREA = 22.^2 ha 3& 590 m • 2.k cm <■ 5 cm • 2 cm tamiu 7Z 1 * * < 1.05 cm-?-1 48 m 500 m ifO m 330 a 1 cm 1.27 1.27 cm 200 m J>oO 3 . AP.2A • =6.45ha ^r 23k m 3 Area 5 Plaster City 'Librcirv 'oral Center Aerial Photograph Calibration Eata - AIEA: 7B Patton Photo Date: 6-9-74 Photo size: 9x9 Photo Nos. BIM-C-M000 17-9, 10, 11 18-7, 8 16-11, 12, 13, 14 3A2IQ: 1:20, 000 Tz-ars parent Grid Measurements On Ground Equivalent Measurements 123^5 a b c r~rr" LI •lo cm each side of sn. aqs* 1*9 cm -2.95 cm 6 1 M [r Area of sm sqs. = .ok ha 2o m ea side of sm sqs. AREA = 22. k2 ha 590 m DU+w .2k cm • £.5 cm •2 cm > * *k 1.05 cm^-1 1 cm 1.27 (^ 1.27 c;m 25^ m 25^ a N V. o "D O M t/1 a § i — •H Q