National Park Service Mojave National Preserve U.S. Department of the Interior Sweeney Granite Mountains Desert Research Center

Science Newsletter

PrehistoricPrehistoric humanhuman settlementsettlement andand lithic technologytechnology arounaroundd Soda LakeLake Edward J. Knell 1

FigureFigurre 2. EEastast ffacingacing overviewoverview ofof the SSodaoda MountaiMountainns surveysurvey area, with ZzZzyzxyzx Road and SSodaoda Lake in the background.background. LongLong beforebefore the MojaveMojave National Preserve thethe potable water, animals and edible bbecameecame “the“the Preserve,” archaeologistsarchaeologists ((manymany associated with now dried up marshesmarshes),), FigureFigure 1. Map ofof SodaSoda LakeLake that iincludesncludes the iinvestigatednvestigated the shorelines ofof its now drydry playaplaya aandnd sousourcesrces of ffineine-grainedgrained volcanic ((FGV)FGV) stone fivefive survesurveyy areas and other keykey features.features. llakesakes to findfind longlong lost remnants ofof past human toto make tools. Results ooff the ongoingongoing In this Issue: acactivities.tivities. ThiThiss work beganbegan in earnest duringduring the archaeologicalarchaeological research described here portrayportray 1930s, with archaeologistsarchaeologists such as Elizabeth howhow TP-EH foragersforagers ororganizedganized their lithic (stone)(stone)  Page 1. Prehistoric human settlement and CCampbellampbell (1, 2) and Malcolm RogersRogers (3) ffindinginding technologytechnology and settlement strategiesstrategies around lithic technology around Soda Lake teterminalrminal PleistocenePleistocene-early-early Holocene ((TP-TP-EH; SodaSoda Lake.  Page 6. What can rigida ~~13,80013,800-9000-9000 cal B.P.)B.P.) ageage artifactsartifacts leleftft byby propagule morphology tell us about rainfall Native Americans alongalong the ancient shorshorelineselines of TThehe CaliforniaCalifornia SStatetate University,University, Fullerton (CS(CSUF)UF) variability and geomorphology in desert ttoday’soday’s SodaSoda Lake. When SodaSoda Lake filledfilled to MMojaveojave Desert ArchaeologyArchaeology ProjectProject (MDAP)(MDAP) ecosystems? ccapacityapacity and its borders breached byby water, the bebegangan in 20092009.. Each summer since, Dr. Knell has  Page 9. The natural history and behavior overoverflowflow fflowedlowed northward into SilverSilver Lake lleded crews ofof student volunteers on systematicsystematic of the sand wasp Steniolia nigripes ccreatingreating pluvial Lake MojaveMojave ((originallyoriginally spelled ppedestrianedestrian (walking)(walking) surveyssurveys to identify,identify, (Hymenoptera: Crabronidae) 2 LakeLake Mohave).Mohave). Lake MoMojavejave was some 300 kmkm document, and record archaeologicalarchaeological sites and  Page 14. Morphological and genetic aatt itsits latelate PleistocPleistocene maximum (~21,900-(~21,900-19,750 analanalyzeyze the stone artifactsartifacts at those sites. Five diversity in reptiles at Mojave National ccalal B.P.),B.P.), but with earlearlyy Holocene warminwarmingg and aareasreas have been survesurveyedyed thus ffarar ((FigureFigure 1).1). Preserve drdryingying between 10,500 and 9600 cal B.P. SodaSoda OOnlynly the SodaSoda Mountains and Little CCowholeowhole  Page 18. Endolithic cyanobacteria in the LLake’sake’s borders were no longerlonger breached and MMountainountain surveysurvey area data are completelcompletelyy : a cold habitat in a hot SSodaoda and SSilverilver Lake became separate playaplaya analanalyzedyzed and the results published; results fromfrom desert? llakesakes (4).). Humans were attracted to the tthehe other survesurveyy areas, and more recent research 1 Department of Anthropology shorelinesshorelines ofof Lake MoMojave,jave, and later the around SilverSilver Lake, are forthcoming.forthcoming. What State University, Fullerton. shorelines ofof SodaSoda and SilverSilver Lake, because ofof ffollowsollows is a summarysummary ofof Knell’sKnell’s currentcurrent

Mojave National Preserve Science Newsletter April 2015 Mountain),Mountain), and even more recently surveyed areas around SilverSilver Lake. ExpandingExpanding the surveysurvey What can Chorizanthe rigida samsampleple to include Soda and Silver Lake will ffacilitateacilitate broad understandinunderstandingg ofof TP-EH-EH propagule morphology tell us technologicaltechnological organizationorganization and settlement around all ofof Lake Mojave.Mojave. BeyondBeyond surveysurvey work, otherother about rainfall variability and ongoingongoing studiestudies seeseekk to:to: 1)1) iincreasncrease the sample of XRF-sourced-sourced lilithicthic mmaterialsaterials ttoo bebettertter geomorphology in desert documentdocument mmobilityobility and land use strategies;strategies; and 2)2) improve understandinunderstandingg ooff Lake MoMojave’sjave’s ecosystems? paleoenvironmental historyhistory throughthrough collaborative Alejandra Martínez-Berdeja and Exequiel Ezcurra 1 research with Dr. Matthew KirbyKirby (CSUF(CSUF DepartmentDepartment ooff GGeologicaleological SSciences).ciences). These and Serotinous plants retain seeds and can delay other planned studies hopehopefullyfully will provide seed dispersal for several months or even years significantsignificant clues regardingregarding past human lifewayslifeways (1). Desert serotinous species have different around Lake MoMojave,jave, and develop context to dispersal syndromes and many have seed more ffullyully inteintegrategrate Lake MoMojavejave into reregionalgional release mechanisms triggered by rainfall. For discussionsdiscussions of TPTP-EH lifewayslifeways in the MoMojavejave instance, some plants, like Oenothera deltoides, DesertDesert andnd GGreatreat BasinBasin.. that grows on sand dunes or Eremothera boothii that grows in sand washes, form lignified ReferencesReferences structures with capsules that release seeds in 1.1. E.E. W. C.C. Campbell,Campbell, ArchaeoloArchaeologicalgical response to rainfall. Another interesting seed ProblemsProblems in the SouthernSouthern CCaliforniaalifornia retention syndrome is that of the desert Deserts.Deserts. Am. Antiq. 1, 295-300295-300 (1936).(1936). spineflower Chorizanthe rigida, a short desert 2. E.E. W. C.C. Campbell,Campbell, et al., Eds., The annual whose lignified seed-retaining structures ArchaeologyArchaeology ofof Pleistocene Lake Mohave: A remain in the field for several years before Symposium.Symposium. (Southwest(Southwest Museum Papers, releasing propagules with rainfall (Figure 1). No.No. 11, Los AnAngeles,geles, 1937).1937). Chorizanthe rigida is common in desert 3.3. M. J. RoRogers,gers, EarlEarlyy Lithic Industries ofof the pavements and is distributed across the North Figure 1. Chorizanthe rigida from the Mojave Lower Basin ofof the ColoradoColorado River and American desert region (2, 3, 4). The objective of Desert. 1 AdjacentAdjacent Areas. SanSan DiegoDiego Museum ofof Man this article is to explore the ecological and Dept. of Botany and Sciences Papers, Vol. 3. (Ballena(Ballena Press, Ramona, evolutionary significance of seed retention in University of California CA,CA, 19391939).). desert serotinous species with specific focus on Riverside, California. 4.4. S.S. G.G. Wells, W. J. Brown, Y. Enzel, R. Y. Anderson,Anderson, L. DD.. McFadden, in Bernardino County, California. Geol. Soc. Deserts, Y. Enzel, S. G. Wells, N. PaleoenvironmentsPaleoenvironments and PaleohydrologyPaleohydrology ofof Am. Bull. 70, 1509-1548 (1959). Lancaster, Eds. (Geological Society of the MoMojavejave and SouthernSouthern GGreatreat Basin 8. J. D. Walker, B. R. Wardlaw, Implications of America Special Paper 368, 2003), pp. 207– Deserts, Y. Enzel, SS.. GG.. Wells, N. Paleozoic and Mesozoic Rocks in the Soda 230. Lancaster, Eds. (G(Geologicaleological SocietySociety ofof Mountains, Northeastern Mojave Desert, AmericaAmerica SSpecialpecial Paper 368, 2003),2003), pp. 7979-- California, for Late Paleozoic and Mesozoic Acknowledgements 114.114. Cordilleran Orogenesis. Geol. Soc. Am. Bull. I thank Daron Duke and Matthew E. Hill, Jr., for their 5. E.E. J.J. Knell,Knell, TerminalTerminal Pleistocene-EarlyPleistocene-Early 101, 1574-1583 (1989). comments and guidance on an earlier version of this HolocHolocene Lithic TechnologicalTechnological OrganizatOrganizationion 9. L. R. V. Joesink-Mandeville, C. Cameron, R. paper, but take responsibility for any around LakeLake MoMojave,jave, CCalifornia.alifornia. J. Field Douglas, “Lake Mojave Archaeological misinterpretations or errors of fact. I also thank the Archaeol.Archaeol. 39, 213213-229-229 (2014).(2014). Report, 1979 Fall Season” (California State many student volunteers who made this research 6. E.E. J. Knell, L. C.C. WaldenWalden--Hurtgen,Hurtgen, M. E. University, Fullerton, Department of possible, the Desert Studies Center staff, as well as Kirby,Kirby, Terminal Pleistocene-Pleistocene-EarlyEarly Holocene Anthropology, 1980). the Begole Archaeological Research Grant Spatio-Spatio-Temporal and SettlementSettlement PattePatternsrns 10. J. L. Semenza, thesis, California State (sponsored by the Colorado Desert Archaeological around Pluvial Lake MojMojave, CCalifornia.alifornia. J. University, Los Angeles (1984). Society) and the California State University Fullerton CA.CA. GB.GB. Anthro. 34, 443-603-60 (2014).(2014). 11. A. M. Harvey, S. G. Wells, in Faculty Development Center (Teaching Mini-Grant 7. L. T. Grose,Grose, StructureStructure and PetrologyPetrology ofof the Paleoenvironments and Paleohydrology of and the State Special Fund Program). Northeast Part ooff the SSodaoda Mountains, San the Mojave and Southern Great Basin

6 Mojave National Preserve Science Newsletter April 2015 C. rigida. Deserts are characterized by low and unpredictable rainfall (5, 6). However, desert rainfall is not completely random; desert regions have different seasonal precipitation patterns. In North America, the Mojave Desert has mostly winter precipitation while the has a bi-seasonal rainfall distribution pattern with both winter and summer rainfall (7). The interaction of rainfall and temperature imposes important challenges to plants: summer rainfall occurs in the hot season of the year when evaporation rates are very high while, in contrast, low temperatures during the long cool season result in low evaporation rates, allowing moisture to last longer in the soil. Moreover, the interaction between rainfall and temperature with the different soil and ground surface desert features results in soil moisture pulses of varying duration and infiltration depth (8).

Desert annuals spend most of their life as seeds (i.e. from a year to even several years), germinating and growing when moisture is available (9). These ephemeral plants display different strategies that allow them to cope with varying degrees of environmental variability and unpredictability (10, 11). For instance, long days and rising temperatures indicate the beginning of the summer, and even if there is available water, winter annuals will not germinate until days shorten and temperatures drop, signaling the beginning of the cool season (12). Furthermore, not all of the seeds of an individual’s cohort will germinate at the same time, a strategy that allows them to spread the risk of germination between years as a “bet-hedging” strategy (10, 11, 13). It has been suggested that delaying seed dispersal and timing of seed release allows desert annuals to cope with environmental variability as well (1, 2). In our research, we addressed two questions related to seed retention in the rigid spineflower: How does C. rigida avoid releasing seeds in response to a Figure 2. Chorizanthe rigida grows in the spring time (top) and its lignified skeletons remain summer rain, a false cue that would prove fatal in the field for several years retaining seeds and releasing them to rainfall (bottom). for seedlings? Does delayed seed dispersal allow flowers produce an achene that matures inside skeleton remaining in the field for several years C. rigida to cope with a highly unpredictable an involucre composed of three spiny bracts. The (Figure 2). C. rigida is distributed from Baja desert environment? propagules of C. rigida are formed by the California’s Central Desert (lat. 29°N) to the involucre containing the achene (Figure 3). The Great Basin in (lat. 40°N) and is common Chorizanthe rigida (rigid spineflower, seed germinates inside the involucre and in the Mojave and Sonoran deserts (Figure 4). ) is a winter desert annual seedlings emerge in the winter season (3, 4). Because of its broad distribution range, C. rigida germinating during the cool season and setting These plants become lignified at the end of its life experiences both different seasonal and within- seed at the end of the spring (Figure 2). Its tiny cycle with the erect, short (2-10 cm), and spiny season rainfall patterns that vary in their

7 Mojave National Preserve Science Newsletter April 2015 predictability, an ideal system to study the adaptations of serotinous species to different levels of environmental variability and unpredictability.

Chorizanthe rigida has an interesting dispersal mechanism: the involucres are attached to the plant by a pedicel that when wet, softens, allowing raindrops to detach them. The remaining attached involucres are retained when both their Figure 3. Chorizanthe rigida propagules pedicels and the plant dry again after the rainfall formed by the involucres (left) containing an achene (right). event occurs. Since the base of the pedicel controls detachment of the involucre, we variation in C. rigida individuals from sites with measured both the involucre base area and the more unpredictable rainfall. By producing many force needed to cause detachment to investigate small seeds and some larger seeds C. rigida may if C. rigida could prevent releasing propagules to display a bet-hedging strategy as seeds of a false summer rain cue. We sampled C. rigida different size have different probabilities of populations occurring at sites that had either surviving and getting established (Figure 3). mostly winter rainfall or a bi-seasonal rainfall Figure 5. Chorizanthe rigida on the desert regime. We found that propagules of plants from Desert pavement surfaces are covered with pavements at the end of the growing season at sites with both summer and winter rainfall had packed rocks of different sizes depending on the Clark Mountains Wilderness Area in the Mojave Desert National Preserve. involucre bases double the size of those from their age and parent material. Soils underlying strict winter rain deserts. We also found that desert pavements are very fine and have availability (18, 19). In contrast to the predictions bases with a larger area required more force to relatively high salt content because they have low of the nurse plant model, the rigid spineflower is detach than those of smaller involucres. Our water infiltration (16). Desert pavements are associated with the apparently harsh results show that different biomechanical surrounded by shrub mounds that have environment of desert pavements. We ecotypes have evolved as a response to different contrasting hydrological and micro-topographical characterized the micro-topographical surface seasonal rainfall patterns allowing C. rigida to conditions. Shrub-mounds have sandy soils with and soil conditions of desert pavements and avoid dispersing seeds to a false summer rainfall good water infiltration and higher nutrient shrub mounds in order to analyze the cue (14). availability from litter decomposition (17). Many microhabitat distribution of C. rigida. We found desert annuals prosper under nurse shrubs that that C. rigida was distributed in the rough edges Rainfall in deserts is erratic; a germination- provide shade and higher nutrient and moisture of desert pavements or in desert pavements causing rain may or may not be followed by formed by large rocks (Figure 5). In contrast to subsequent rainfall events (6). To cope with nurse-shrub associated desert annuals whose unpredictability, many desert annuals have seeds get dispersed by wind or animals into the evolved bet-hedging strategies such as soil seed shrub mounds at the end of the growing season, banking (10, 13). A less explored bet-hedging C. rigida retains its seeds and synchronizes seed trait is seed size. In a randomly varying releases with winter rainfall. By doing this, the environment, plants should produce a variable propagules of C. rigida are dispersed by runoff to cohort of seed sizes, with many small seeds that desert pavement surfaces, germinating have high survival probabilities in a favorable immediately after rains at a time when there is season and some large seeds that have higher available moisture in the soil. Timing seed survival probabilities in an unfavorable year that release lets C. rigida establish in desert would allow them to achieve long–term pavements which provide stable conditions persistence (14). Given that C. rigida retains its necessary for long-term persistence of the dead entire seed cohort in its tissues, it is an excellent seed-retaining skeletons until the next rain event system to investigate bet-hedging theory occurs (20). predictions regarding within-individual seed size variation. We collected plants from sites varying Despite the extreme variability and in winter rainfall unpredictability and performed unpredictability of desert ecosystems, seed Figure 4. Chorizanthe rigida is distributed retention and timing of seed release to seasonal morphometric measurements on the propagules. from the Mojave (blue) to the Sonoran (red) Our results showed that there is higher seed size deserts. rain cues allows C. rigida to thrive during brief

8 Mojave National Preserve Science Newsletter April 2015 windows of opportunity. Seed size variation in individual plants may allow C. rigida to cope with TheThe naturalnatural hihistorystory anandd desert rainfall unpredictabitility, and to persist through harsh years. behavior ooff the sand waspwasp

References StenioliaSteniolia nigripesnigripes 1. van Rheede van Oudtshoorn, K., M. W. van Rooyen, Dispersal Biology of Desert Plants, (Hymenoptera:(Hymenoptera: CrabronidaeCrabronidae)) (Adaptations of Desert Organisms. Springer, GileneGilene M. YoungYoung 1 Berlin, 1999). 2. Ellner, S., A. Shmida, Why are adaptations SandSand wasps (Crabronidae:(Crabronidae: Bembicinae)Bembicinae) ethologistethologist Niko Tinbergen.Tinbergen. ManyMany solitarysolitary wasps for long-range seed dispersal rare in desert demonstrate an arraarrayy ooff interestininterestingg bebehavioralhavioral are large,large, bribrightlyghtly colored,colored, and ffascinatingascinating to plants? Oecologia 51, 133–144 (1981). and morpholomorphologicalgical traits (1,1, 2, 3),), but manmanyy ofof the observe. AlthouAlthoughgh thetheyy do not cooperate in nestnest-- 3. Felger, R. S., Flora of the Gran Desierto and approximatelapproximatelyy 1,700 species have not been bbuildinguilding as social species do, solitarsolitaryy wasps oftenoften Río Colorado of Northwestern Mexico, (The investiinvestigatedgated in depth. I ststudiedudied a population ooff aaggregateggregate in largelarge numbers. TheseThese featuresfeatures havehave University of Press, United States of SStenioliateniolia ninigripesgripes located at the GraniteGranite attracted naturalists to the studystudy ooff solitarsolitaryy wasps America, 2000). Mountains in the MojaveMojave Desert, CCalifornia,alifornia, ffromrom forfor well over a centurycentury (4,4, 5).The).The sand wasps 4. Baldwin, B. G., S. Boyd, B. J. Ertter, R. W. 2008 to 2013.2013. I present ininformationformation on the (Crabronidae:(Crabronidae: BembicinaeBembicinae)) are an appealinappealingg Patterson, T. J. Rosatti, D. H. Wilken, The distribution and habitat ofof these wasps, as well as groupgroup ooff wasps with ggreatreat variation in theitheirr Jepson Desert Manual. Vascular plants of seasonal patterns in population size and location. behaviorbehavior and extensive species diversitydiversity (6).). Southeastern California, (University of I also discuss the response ooff SStenioliateniolia nigripesnigripes Indeed,Indeed, the Bembicinae are the second largestlargest California Press, Canada, 2002). ttoo environmental variation.variation. In addition, I describe subfamilysubfamily ooff the sphecid wasps, containingcontaining overover 5. Noy-Meir, I., Desert ecosystems: tthehe behavior ooff wasps ooff both sexes, includinincludingg 8800 generagenera and more than 1,700 species (4,4, 5).). environment and producers. Annual Review fforaging,oraging, preyprey selection, aggression,aggression, and space TThishis diversitydiversity ofof species and the correspondingcorresponding of Ecology and Systematics 4, 25–41 uuse.se. This paper represents the ffirstirst trulytruly diversitdiversityy ofof behavior prpresentesent in the Bembicinae (1973). ccomprehensiveomprehensive description ooff S.S. nigripesnigripes naturalnatural 1 6. Ezcurra, E., V. Rodrigues, Rainfall patterns historhistoryy and behavior.behavior. Department ooff EcoloEcologygy & EvolutionaryEvolutionary BiologyBiology in the Gran Desierto, , Mexico. SolitarySolitary wasps have lonlongg been ooff special interestinterest UniversityUniversity ooff CCaliforniaalifornia Journal of Arid Environments 10, 13–28 to bebehavioralhavioral bbiologists,iologists, includingincluding the foundationalfoundational LosLos Angeles,Angeles, CA. (1986). 7. Reynolds, J. F., P. R. Kemp, K. Ogle, R. J. Springer, Berlin 1993). pp. 1–22, 1985). Fernández, Modifying the ‘pulse-reserve’ 13. Philippi, T., Bet-hedging germination of 18. Franco, A.C., P.S. Nobel, Effect of nurse paradigm for deserts of North America: desert annuals: beyond the first year. plants on the microhabitat and growth of precipitation pulses, soil water, and plant American Naturalist 142, 474–487 (1993). cacti. Journal of Ecology 77, 870–886 responses. Oecologia 141, 194–210 (2004). 14. Martínez-Berdeja, A., M.Torres, D. L. (1989). 8. Loik, M. E., D. D. Brashears, W. K. Altshuler, E. Ezcurra, Hydration history and 19. Valiente-Banuet, A., E. Ezcurra, Shade as a Lauenroth, J. Belnap, A multi-scale attachment morphology regulate seed cause of the association between the cactus perspective of water pulses in dryland release in Chorizanthe rigida Neobuxbaumia tetetzo and the nurse plant ecosystems: climatology and ecohydrology (Polygonaceae), a serotinous desert annual. Mimosa luisana in the Tehuacán Valley, of the western USA. Oecologia 141, 269– American Journal of Botany 101, (2014). Mexico. Journal of Ecology 79, 961–970 281 (2004). 15. Olofsson, H., J.Ripa, N. Jonzén, Bet- (1991). 9. Mulroy, W. T., P. W. Rundel, Annual plants: hedging as an evolutionary game: the trade- 20. Martínez-Berdeja, A., N. Pietrasiak, A. adaptations to desert environments. off between egg size and number. Tamase, E. Ezcurra, E. B. Allen, Living BioScience 27, 109–114 (1977). Proceedings of the Royal Society B. (2009). where others dare not: Microhabitat 10. Cohen, D., Optimizing reproduction in a 16. Wood, Y.A., R.C. Graham, S. G. Wells, distribution in Chorizanthe rigida, a randomly varying environment. Journal of Surface mosaic map unit development for a serotinous desert annual. Journal of Arid Theoretical Biology 12, 119–129 (1966). desert pavement surface. Journal of Arid Environments 97, 120–126 (2013). 11. Venable, D.L. Bet hedging in a guild of Environments 52, 305–317 (2002). desert annuals. Ecology 5, 1086–1090 17. Evenari, M., The desert environment. Acknowledgements (2007). Ecosystems of the World. Hot Deserts and We thank Andrew D. Turner for the drawings for this 12. Gutterman, T. Seed Germination in Desert Arid Shrublands. Part 12A, (Elsevier publication. We thank Andy Sanders and Nicole Plants. (Adaptations of Desert Organisms. Science Publishing Company, New York, Pietrasiak for their help in the different research projects.

9 Mojave National Preserve Science Newsletter April 2015