Pollen analysis of fossil dung of Ovis canadensis from southern Nevada
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Authors Spaulding, Walter Geoffrey, 1950-
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Link to Item http://hdl.handle.net/10150/566368 POLLEN ANALYSIS OF FOSSIL DUNG OF OVIS
CANADENSIS FROM SOUTHERN NEVADA
by
W alter Geoffrey Spaulding
A Thesis Submitted to the Faculty of the
DEPARTMENT OF GEOSCIENCES
In Partial Fulfillment of the Requirements for the Degree of
MASTER OF SCIENCE
In the Graduate College
THE UNIVERSITY OF ARIZONA
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This thesis has been submitted in partial fulfillment of re quirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library.
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SIGNED:
APPROVAL BY THESIS DIRECTOR
This thesis has been approved on the date shown below: QMQh<. n QuMf ALLEN M . SOLOMON V The research for this report was done at the Laboratory of Pa- leoenvironmental Studies, Department of Geosciences, The University of Arizona, under the direction of A. M. Solomon. The aid of the per sonnel of the Desert National Wildlife Refuge, Las Vegas, Nevada, particularly Jack He Ivy and James Constantino, was invaluable. Field work was done with the aid of C. W. Ogston, A. M. Solomon, and J. E. King. Austin Long of the Laboratory of Isotope Geochemistry, The University of Arizona, provided two radiocarbon dates. Richard Brooks of the University of Nevada, Las Vegas, first directed our attention to the area, and P. S. Martin encouraged its study. Plant specimens were identified at the Herbarium of The University of Arizona by C. T. Mason and Richard Halse. iii TABLE OF CONTENTS Page LIST OF TABLES...... v LIST OF ILLUSTRATIONS...... vi ABSTRACT...... vii INTRODUCTION...... 1 The Vegetation and Physiography of the Study Area ...... 2 METHODS AND PROCEDURES...... 10 Sample C o lle c tio n ...... 10 Pollen E xtraction...... 10 RESULTS...... 14 Vegetation S tu d y ...... 14 Pollen A n aly sis...... 24 Flaherty Shelter Stratigraphy ...... 30 D ISC U SSIO N ...... 36 The H olocene V egetation...... 36 Desert Bighorn Behavior...... 38 CONCLUSIONS...... 44 APPENDIX: POLLEN COUNTS AND RELATIVE FREQUENCIES...... 46 REFERENCES...... 54 iv LIST OF ILLUSTRATIONS Figure Page 1. Study area in C lark County, N e v a d a ...... 3 2. Flaherty S h e l t e r ...... 5 3. Relative frequencies of anemophilous pollen from fecal pellets from Cow Camp Spring, Clark County, Nevada . . 26 4. Relative frequencies of entomophilous pollen from fecal pellets from Cow Camp Spring, Clark County, Nevada . . 27 5. Relative frequencies of anemophilous pollen from samples from Flaherty Shelter Unit I, Clark County, Nevada .... 28 6. Relative frequencies of entomophilous pollen from samples from Flaherty Shelter Unit I, Clark County, Nevada .... 29 7. Pollen grain, undeterm ined type 1...... 31 8. Flaherty Shelter Unit I ...... 33 9. View south from the east side of the Sheep Range...... 42 vi ABSTRACT The Sheep Range of southern Nevada is in Clark County, 35 km north of Las Vegas. Postglacial-age dung deposits of the desert bighorn sheep (Ovis canadensis) occur there in large rock shelters between 1,525 and 1,830 meters elevation. I excavated Flaherty Shelter (1,650 meters elevation) and studied the pollen content of the ancient feces. A sample (A-1296), 2.5 cm from the top of the deposit, was dated at 2,400 + 150 radiocarbon years old, and a sample (A-1297), 47.5 cm from the top (2.5 cm from the bottom of the top unit) was dated at 6,950 + 320 radiocarbon years. I compared relative pollen frequencies from the dung midden to those from modern fecal pellets collected semimonthly in the Sheep Range. On the basis of the modern analog, the prehistoric occupation of Flaherty Shelter was determined to have been restricted to late spring or early summer. There was no apparent deviation from this pattern over 4,500 years. This study shows that, while pollen analysis of large-herbivore feces is not ideal for the study of past climates, the method will aid in reconstructing seasonal migration patterns, food habits, and other fea tures of herbivore life history through time. vii INTRODUCTION Fossil herbivore dung has long been recognized as a source of paleoecological information. Analysis of plant cuticles in dung is a useful tool to interpret past environments (Laudermilk and Munz 1934, Iberall 1972). Pollen analysis of herbivore coprolites is seldom at tempted. The purpose of this study is to probe some limitations in the use of pollen in fossil herbivore dung and to describe the information that may be obtained. Work with the remarkable organic deposits found in certain desert caves may give some new insight into their paleoeco logical potential. A primary assumption in this study is that pollen from herbivore feces cannot be treated in the same manner as that from an open basin of deposition. The factors affecting the relative pollen content of her bivore feces must be studied. Movements of the animal, selective feed ing habits, random pollen ingestion, seasonal habitation, and plant phenology must be considered in order to determine the limitations and possible interpretations. Variables associated with pollen deposition in limnetic sediments, such as differential pollen sedimentation (Davis and Brubaker 1973) and differential preservation and redeposition, either do not apply here or operate differently in fecal deposits. Bartos (1972) has examined modern mule deer fecal pellets with these problems in mind. To provide some control in the pollen analysis of the Flahe^TShelter dung, the vegetation of the area and fecal pellets of modern bighorn were studied. 1 2 Past paleoecological studies in southern Nevada on late Pleisto cene packrat (Neotoma sp.) middens (Wells and Jorgensen 1964, Wells and Berger 1967), alluvial and lacustrine deposits in the Las Vegas Val ley (Wormington and Ellis 1967), and ground sloth (Nothrotheriops shas- tense) dung from Gypsum Cave (Laudermilk and Munz 1934) have little direct bearing on this study. On the basis of fossil pollen in the Las Vegas Valley, Mehringer (1967) concluded that, in the last 7,000 years, there has been no major climatic change in southern Nevada. Following Bartos' (1972) study, some limitations and potential uses of copropalynology are examined. Previous climatic interpretations based on pollen in feces (Martin, Sabels and Shutler 1961) are examined. This study also attempts to establish whether the prehistoric occupation of Flaherty Shelter by bighorn sheep was seasonal. The fossil pollen in Flaherty Shelter may support or modify Mehringer's (1967) conclusion that there has been no major climatic change in this area during the mid dle and late Holocene. The Vegetation and Physiography of the Study Area The Sheep Range ranges in elevation from 1,220 m at its south ern base to 3,022 m at Hayford Peak (Fig. 1). It is uptilted in a manner typical of block faulting in the Basin and Range province. There are steep scarps on the west side and gentle slopes down to the bajada on the east. The central axis of the range runs north-south. The major basins bordering the southern half of the range are the Las Vegas Val ley on the west and the Yucca Forest Valley on the east. The largest mountain range in southern Nevada, the Spring Range, lies across the 2 0 0 0 FOSSIL ’ RIDGE •GASS PEAK 1000 CCS-Cow Comp Spring F S - Flaherty Shelter TS - Tula Springs Contour Intervol 1 500m 15 Km NEVADA LAS VEGAS ARIZONA CALIFORNIA Figure 1. Study area in Clark County, Nevada Base data from U.S. Geological Survey, Las Vegas, Nevada, 1:250,000 topographic sheet. 4 Las Vegas Valley to the southwest. The physiographic boundary between the Great Basin and the Mohave Desert is formed, in part, by the Sheep Range (Morrison 1965). The lower slopes of the Sheep Range, mostly below 1,980 m, are highly dissected, in contrast with the gently rounded aspect of the upper reaches. Rock shelters abound on the sides of isolated crests and mesas in the Paleozoic limestone of the lower portion of the range. Flaherty Shelter, at 1,650 m on the east side of the Sheep Range, appears to be a large solution cavity. It lies at the base of a 20-meter cliff, which is at the top of a talus slope 70 m above a desert wash (Fig. 2). The shelter was formed in the contact zone between a massive lime stone unit above and a more finely bedded one beneath. The mouth of the shelter faces 15° east of north. It is 17.9 m wide and approximately 10 m high. From the drip line at the front of the shelter to the back of the cave measures 11.7 m. The vegetation was studied by reconnaissance and was analyzed by belt-transects near Flaherty Shelter and at Cow Camp Spring at 1,830 m on the west side of the range. Both sites are at the upper elevational limit of the blackbrush (Coleoqyne ramosissima) zone. The difference in species composition and numbers between the two microhabitats seems to be accentuated by a composition of irregular topography, xeric lime stone soils, and high altitude. Floristically, these sites could be said to lie in either the southern Great Basin Desert or Mohave Desert. Plants common to both regions are found in close association with one another. Above 1,580 m in the Sheep Range, relatively uniform stands of C. ramosissima and Gutierrezia sarothrae (snake-weed) on north-facing 5 Figure 2. Flaherty Shelter The shelter is approximately 20 m wide at its mouth. Most of the plants in the foreground are Gutierrezia sarothrae. 6 talus slopes abruptly give way to Artemisia tridentata (big sagebrush), Ephedra viridis (joint-fir), Rhus trilobata (skunk-bush), and Symphori- carpos longiflorus (snowberry) at the base of north-facing scarps. In the most protected spots, under these scarps, Petrophytum caespitosum (rock-mat), Cercocarpus ledifolius (mountain mahogany), Juniperus osteosperma (Utah juniper), and Pinus monophylla (single-leaf pinyon) can be found. Near rare seeps and springs, Atriplex canescens (chamiso) and Phragmites communis (reed-grass) grow with Salix lasiolepis (arroyo willow) in dense thickets. These species are included by Bradley and Deacon (1967) in the riparian and cliff community. Above the scarps on flat, exposed crests, such as the Cow Camp Spring area, are xeric species, such as Yucca brevifolia (Joshua- tree), Opuntia basilaris (beavertail cactus), Ephedra nevadensis (Mormon-tea), Gutierrezia sarothrae, and Coleogyne ramosissima. Joshua-tree is also widely distributed on south-facing talus slopes be low 1,800 m. Yucca baccata (banana-yucca), normally restricted to the upper bajada and dry washes, is found on the south-facing slopes. Ele ments of the riparian and cliff community are rare on these xeric expo sures. Isolated stands of Larrea tridentata (creosote-bush) are found as high as 1,860 m on south-facing talus slopes. Other perennial species common here are Coldenia canescens, Fallugia paradoxa (Apache-plume), Cowania mexicana (cliff-rose), and Salazaria mexicana (bladder-sage) . Annuals commonly found on south-facing talus slopes or ex posed crests at these elevations include Euphorbia robusta (spurge), Cryptantha flavoculata, Draba cuneifolia. Anemone tuberosa (anemone), 7 Astragalus mohavensis (loco-weed), and Eriogonum inflatum (desert- trumpet) . The most diverse community is in the bottoms of the major drainages of the Sheep range. Along with the species listed as common on the crests and south-facing slopes are Thamnosma montana (turpentine-broom), Tetradymia axillaris (horse-brush), Chrysothamnus nauseosus (rabbit-brush), Glossopetalon nevadense (grease-bush), and Salvia dorrii (desert-sage). Cacti are common in these dry washes and include Opuntia echinocarpa (silver cholla), Opuntia acanthocarpa (buck- horn cholla), Echinocactus polycephalus (cotton-top cactus), Neolloydia johnsonii, and Opuntia basilaris. Table 1 contains a list of all the plants identified at Cow Camp Spring and Flaherty Shelter. 8 Table 1. Plants from the vicinity of Cow Camp Spring and Flaherty Shelter Flaherty Cow Camp Family Species Shelter Spring Ac a nth ace ae Rhus trilobata XX Boraginaceae Coldenia canescens X Cryptantha flavoculata XX Cactaceae Echinocactus polycephalus X Neolloydia johnsoni XX Opuntia acanthocarpa X Opuntia basilaris X X Opuntia cf. polyacantha X Opuntia echinocarpa X X Caprifoliaceae Symphoricarpos longiflorus XX Celastraceae Glossopetalon nevadense X Chenopodiaceae Atriplex canescens X X Eurotia lanata X X C om positae Artemisia tridentata X X Chrysothamnus nauseosus X X Encelia frutescens X Gutierrezia sarothrae X X Haplopappus sp. cf. Perezia wrightii X Tetradymia axillaris X Cruciferae Draba cuneifolia X Lepidium sp. X Cupressaceae Juniperus osteosperma XX Ephedraceae Ephedra nevadensis X X Ephedra viridis X X Euphorbiaceae Euphorbia robusta X G ram ineae Phragmites communis X Labiatae Salazaria mexicana X Salvia dorrii X X Leguminosae Astragalus mohavensis X X D ale a sp . L iliaceae Yucca baccata X Yucca brevifolia X X 9 Table 1. Plants—Continued Flaherty Cow Camp Family Species Shelter Spring Loganiaceae Buddieja utahensis X M alvaceae Sphaeralcia ambigua XX Onagraceae Oenothera sp. X Pinaceae Pinus monophylla X X Polemoniaceae Cilia sp. X Polygonaceae Eriogonum heermanni X Eriogonum inflatum X Ranunculaceae Anemone tuberosa X Rosaceae Coleogyne ramosissima X X Cowania mexicana X X Fallugia paradoxa X X Rubiaceae Galium sp . X Rutaceae Thamnosma montana X X S alicaceae Salix lasiolepis X Scrophulariaceae Penstemon palmeri X Penstemon petiolatus X Solanaceae Lycium andersonii X X Nicotiana trigonophylla X Zygophyllaceae Larrea tridentata X METHODS AND PROCEDURES Sample Collection A fresh vertical surface was made in the Flaherty Shelter de posit. Samples were collected at 2.5-cm intervals for the first 70 cm. A 10-cm interval was used in excavating below the indurated dung to prevent slumping of poorly consolidated sediments. About 50 grams of material was removed from each level and placed in sterile Whirl-Pak plastic bags. Additional samples were taken for macro fossil analysis. Fresh bighorn pellets were collected semimonthly by personnel of the Desert National Wildlife Range at Cow Camp Spring. This peren nial seep above a deep wash is in constant use by desert bighorn. Since snow makes Cow Camp Spring inaccessible during the winter, samples are lacking for most of this season. The number of pellet-groups collected in one sampling interval varied. A pellet-group is defined as the pellets voided by one animal at one time (Bennett, English and McCain 1940). An average of 50 pellets per group are voided by bighorn sheep and one animal averages 13 pellet- groups a day (Iberall 1972). Pollen Extraction Samples were washed gently to remove contaminants adhering to the surface. The consolidated nature of both the modern and fossil samples allows this to be done under running water without dissolution. After washing, they were dried and weighed. Modern fecal pellets were 10 11 divided in half, one part for pollen analysis, one for future cuticle anal- s is . The extraction of pollen from fecal material closely follows that described by Bartos (1972) with modifications to suit the nature of the samples. Since the fossil dung has a high carbonate content, it requires a preliminary treatment with 50% hydrochloric acid (step 7, Table 2). Two hot water rinses immediately after the 70% hydrofluoric acid wash reduce the amount of colloid in the sample (steps 10, 11). A standard solution of one part sulfuric acid to nine parts acetic anhydride was used for acetolysis (Faegri and Iversen 1964). The 15% nitric acid wash was followed by the potassium hydroxide wash (step 21). Once the samples were placed in a glycerol medium, two drops of a solution of 5% phenol in ethyl alcohol were added to prevent fungus growth (step 28). Safranin O stain was added to all samples. 12 Table 2. Summary of extraction procedures for fossil and modern fecal sam ples Step Description 1 Wash samples gently 2 Cover samples with 3% trisodium phosphate 3 Macerate and heat at 60°C for 48 hours 4 Wash with distilled water through 100 mesh brass screen, centrifuge and decant 5 Hot distilled water rinse, centrifuge and decant 6 Repeat 7 50% hydrochloric acid wash, centrifuge and decant 8 Concentrated hydrochloric acid wash, centrifuge and decant 9 70% hydrofluoric acid wash, centrifuge and decant 10 Hot distilled water rinse, centrifuge and decant 11 Repeat 12 Glacial acetic acid rinse, centrifuge and decant 13 Repeat 14 Add acetolysis solution, immerse samples for 2 minutes in boiling water bath, centrifuge and decant 15 Glacial acetic acid rinse, centrifuge and decant 16 Repeat 17 Hot distilled water rinse, centrifuge and decant 18 15% nitric acid wash, 2 minutes in boiling water bath, centrifuge and decant 19 Hot distilled water rinse, centrifuge and decant 20 Repeat until decant is clear 21 5% potassium hydroxide wash, immerse for 2 minutes in boiling water bath, centrifuge and decant 13 Table 2 . Summary of extraction procedures—Continued Step Description 22 Hot distilled water rinse, centrifuge and decant 23 Repeat until decant is clear 24 95% ethyl alcohol rinse, centrifuge and decant 25 Repeat, decanting samples into vials 26 Centrifuge and decant vials 27 Add glycerol to vials, heat at 60°C until all ethyl alcohol evaporates 28 Add desired stain and two drops of 5% phenol in ethyl alcohol RESULTS The vegetation around Cow Camp Spring and Flaherty Shelter was analyzed to obtain a quantitative view of the differences between the plant assemblages at the two sites. It was hoped that this might provide insight into the reasons for the differences between the pollen spectra of the modern and fossil dung. The stratigraphy of Flaherty Shel ter was examined in some detail in a search for causes for the initiation of dung deposition and its subsequent cessation. Vegetation Study Two vegetation belt-transects were laid out at Cow Camp Spring and two at Flaherty Shelter. Each was 50 m long and consisted of 25 quadrats, each 2 m square. They were laid out on level and sloping ground. Each plant growing within a quadrat was counted. These data are presented in Tables 3 through 6. Values for frequency (F), density (D), and abundance (A) given in Table 7 were derived as follows (Curtis and McIntosh 1950): p _ number of quadrats in which a species occurs x jqq total number of quadrats examined p> = total number of individuals of a species found total area examined A = total number of individuals found x ^qq _ _D_ x ^qq number of quadrats of occurrence F Table 7 presents the combined values for the two belt-transects at Cow Camp Spring and those at Flaherty Shelter. Atriplex canescens and 14 Table 3. Species occurrence per quadrat, belt-transect 1, Cow Camp Spring (Quadrats 1 through 14 are on a slope, 15 through 25 on level ground) Quadrat Number S pecies 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Coleogyne ramosissima 8 6 5 6 4 2 2 1 2 2 4 2 1 Opuntia basilaris 1 Sphaeralcia ambiqua 3 Gutierrezia sarothrae 1 1 5 3 1 Thamnosma montana 1 1 Yucca brevifolia 1 Ephedra viridis 1 Atriplex canescens 1 Chrysothamnus nauseosus Total number of species 111111222 4 2 2 3 2 Total number of plants 865642342 9 3 5 6 2 Table 3. Species occurrence per quadrat, belt-transect 1, Cow Camp Spring—Continued Quadrat Number Species 15 16 17 18 19 20 21 22 23 24 25 Coleoqyne ramosissima 1 Opuntia basilaris 1 Sphaeralcia ambiqua 1 1 2 1 4 11 3 5 Gutierrezia sarothrae 2 2 10 6 5 11 4 6 2 Thamnosma montana Yucca brevifolia Ephedra viridis Atriplex canescens 2 8 7 2 1 1 2 2 Chrysothamnus nauseosus 1 • 1 1 1 1 1 Total number of species 4 2 4 3 4 2 1 3 3 3 4 Total number of plants 5 4 20 14 10 12 4 6 13 11 10 Table 4 . Species occurrence per quadrat, belt-transect 2, Cow Camp Spring (Quadrats 1 through 16 are on level ground, 17 through 22 on a ridge, and 23 through 25 in a w a sh .) Quadrat Number Species 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Coleogyne ramosissima 1 Sphaeralcia ambigua 5 1 2 1 1 Gutierrezia sarothrae 4 5 10 14 9 1 6 Ephedra viridis 2 Atriplex canescens 1 3 2 3 1 1 2 2 1 2 3 Chrysothamnus nauseosus 1 Phraqmites communis a a a a Symphoricarpos lonqiflorus 1 1 Rhus trilobata Cowania mexicana Artemisia tridentata Total number of species 4 2 2 2 2 i 1 1 2 2 3 3 3 4 Total number of plants 11 4 4 a a a a 1 6 12 17 11 4 12 a. Individuals not counted, abundant. Table 4. Species occurrence per quadrat, belt-transect 2, Cow Camp Spring—Continued Quadrant Number Species 15 16 17 18 19 20 21 22 23 24 25 Coleoqyne ramosissima 1 1 1 3 3 4 1 Sphaeralcia ambiqua Gutierrezia sarothrae 3 4 1 1 Ephedra viridis 1 1 Atrip lex canescens 2 2 1 Chrysothamnus nauseosus Phragmites communis Symphoricarpos lonqiflorus 2 4 1 Rhus trilobata 2 Cowania mexicana 1 Artemisia tridentata 1 Total number of species 4 4 2 1 3 1 2 1 2 0 2 Total number of plants 7 11 3 3 5 4 •2 1 3 0 2 Table 5. Species occurrence per quadrat, belt-transect 3, Flaherty Shelter (From the drip line at the mouth of the shelter down the talus slope.) Quadrat Number Species 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Coleoqyne ramosissima Sphaeralcia ambiqua 3 1 Gutierrezia sarothrae 2 3 2 2 1 3 1 7 4 1 5 2 4 Yucca brevifolia Ephedra viridis 1 Atrinlex canescens 1 Symphoricarpos lonqiflorus 2 1 Cowania mexicana 1 1 2 Lycium sp . 1 3 16 Glossopetalon nevadense 1 2 2 1 Neolloydia iohnsoni 1 Penstemon petiolatus 1 Total number of species 3 2 4 3 1 3 3 4 2 1 2 1 1 1 Total number of plants 5 4 6 5 2 5 5 21 8 4 2 5 2 4 Table 5. Species occurrence per quadrat, belt-transect 3, Flaherty Shelter—Continued Quadrat Number Species 15 16 17 18 19 20 21 22 23 24 25 Coleoqyne ramosissima 1 1 1 1 Sphaeralcia ambiqua Gutierrezia sarothrae 5 463451342 Yucca brevifolia 1 Ephedra viridis 1 Atriplex canescens Symphoricarpos lonqiflorus Cowania mexicana Lycium s p . Glossopetalon nevadense 1 16 2 Neolloydia johnsoni Penstemon petiolatus Total number of species 2 3 2 2 1 1 1 2 1 2 2 Total number of plants 6 18 5 8 3 4 5 2 3 5 3 Table 6. Species occurrence per quadrat, belt-transect 4, Flaherty Shelter (At top of talus slope, 2 to 6 m in front of the cliff face; quadrats 5 through 16 are in front of the mouth of Flaherty Shelter.) Quadrat Number Species 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Gutierrezia sarothrae 2 2 1 1 3 1 2 1 4 6 4 Ephedra viridis 1 Symphoricarpos lonqiflorus 3 1 4 3 2 2 3 4 Glossopetalon nevadense 1 Lycium sp. 1 1 1 2 Rhus trilobata Eurotia lanata Galium sp . 6 1 1 Eriogonum heermannii Total number of species 312222133 1 3 1 2 2 Total number of plants 924225355 2 4 4 9 8 Table 6. Species occurrence per quadrat, belt-transect 4, Flaherty Shelter—Continued Species 15 16 17 18 19 20 21 22 23 24 25 Gutierrezia sarothrae 1 Ephedra viridis Symphoricarpos longiflorus 3 3 2 1 1 1 Glossopetalon nevadense Lycium sp . 2 Rhus trilobata 1 1 1 2 Eurotia lanata 1 Galium sp . 2 2 1 5 3 Erioqonum heermannii 1 2 Total number of species 2 3 2 1 2 1 2 0 2 3 2 Total number of plants 4 6 3 2 3 2 2 0 6 5 3 23 Table 7. Summary of frequency, density, and abundance values (Given for species in belt-transects at Cow Camp Spring (CCS) and Flaherty Shelter (FS).) Frequency D ensity Abundance Species CCS FS CCS FS CCS FS Artemisia tridentata 2% — — — .005 • —- — — .02 — — — Atriplex canescens 46% 2% .260 .005 1.04 .02 Chrysothamnus nauseosus 12% — .030 — .14 — Coleoqyne ramosissima 44% 8% .110 .020 1.20 .08 Cowania mexicana 2% 6% .005 .015 .20 .08 Ephedra viridis 10% 6% .025 .015 .10 .06 Erioqonum heermannii — —— 4% — .010 -- — .04 Eurotia lanata — 2% ---— .005 — .02 Galium sp . — 16% — .040 — .42 Glossopetalon nevadense — 16% — .040 — .52 Gutierrezia sarothrae 30% 64% .075 .160 1.20 1.90 Lycium sp . — — — 6% — .015 — .40 Neolloydia johnsoni — 2% — .005 — .02 Opuntia basilaris 4% — .010 — .40 ---— Penstemon petiolatus — 2% — — — — — .02 Phragmites communis 16% — —— a — a — Rhus trilobata 2% — .005 — .04 ---— Sphaeralcia ambiqua 30% 4% .075 .010 .82 .80 Symphoricarpos lonqiflorus 8% 30% .020 .075 .16 .70 Thamnosma montana 4% — .010 — .04 — Yucca brevifolia 2% 2% .005 .005 .02 .20 a. Not measured 24 Coleogyne ramosissima are codominant species at Cow Camp Spring. However, the former occurs on level areas, while the latter is restricted to the slopes (Table 3). Gutierrezia sarothrae and Sphaeralcia ambigua (desert-mallow) are subdominants. G_. sarothrae is also most common on level areas at Cow Camp Spring (Tables 3 and 4). At Flaherty Shelter, (3. sarothrae and ambigua are common on the slope and Coleogyne occurs only at great distances from the north-facing cliff. Coleogyne appears to be intolerant of shady conditions. The cliff-face community at Flaherty Shelter was measured by belt-transect 4 (Table 6). The greatest number of bighorn trails and bed ding areas is in this community, at the top of the talus slope. In the vicinity of Flaherty Shelter, the outwash or organic debris from the shel ter mouth has significantly affected the cliff-face community. The effect of the fecal outwash on the plants was measured as the difference be tween the number of plants in quadrats below the shelter mouth and the quadrats to each side (Table 6). The difference was significant at the 0.05 probability level, showing that more plants grow below the shelter (an average of 4.92 per quadrat) than to each side (2.77 per quadrat). Coverage or plant size was not measured, since these parameters are not as useful in comparing the relative pollen assemblages of two sites as the number of individuals of different species occurring in a given area. Pollen Analysis To determine whether the occupation of Flaherty Shelter was seasonal, pollen types indicative of seasons were chosen from the mod ern and fossil pollen spectra. A number of criteria were used to select 25 these types: (1) they must be well represented in the modern and fossil samples, (2) they must exhibit seasonal variation in the modern spec trum, and (3) they must be free of large, nonseasonal oscillations. On this basis, four pollen types were chosen as the most reliable indicators of seasonality. In the modern spectrum (Figs. 3,4), relative percentages of Gramineae usually exceed 40% from late summer through winter and they are normally below 20% in the spring and early summer. Ephedra nevadensis-type frequencies greater than 10% in the modern spectrum occur only in early and middle spring. From late spring to middle summer, Cheno-am pollen has relative frequencies usually exceeding 30%. Cerco- carpus-type pollen normally exceeds relative frequencies of 15% in spring and early summer. Pollen counts and percentages appear in the appendix. Some important anemophilous types in the fossil profile do not have modern seasonal counterparts (Figs. 5, 6). Arboreal pollen (AP) and short-spine Compositae (Martin, 1963), for example, exhibit much higher values in the fossil material. This could have been caused by the way deposition went on in Flaherty Shelter. Pellets, once voided, were trampled, urinated upon, and left exposed. Pollen blown into the shelter might fall onto this top layer and be eventually covered by another layer. If this happens, fluctuations in the amount of anemophilous pollen in the samples could reflect a varying rate of deposition. More wind-blown pollen would accumulate if deposition were slower, less if deposition were faster. Because of the lack of quantifiable data on the differences between the modern and fossil bighorn dung, I favor this explanation over any based on undocumented vegetation change over the last 2,500 years. Winter Summer c h e n o - a m . Short Spine COMPOSITAE . Ephedro torrevona - type Eohcdro nevodensil - type Junioerm _ 260 390 393 130 260 260 130 264 260 260 260 130 260 260 260 130 390 130 130 Sample Interval 10 11 16 17 18 19 20 21 22 • ‘ 2% h-40%-1 Figure 3. Relative frequencies of anemophilous pollen from fecal pellets from Cow Camp Spring, Clark County, Nevada Fecal pellets were collected semimonthly. WINTER SPRING SUMMER FALL 4 fx” f V ^ , K Long Spine COMPOSITAE. ------_ rffii______- , Ligulilloroe. • * i i i ; Seneeio-type. ------;— i MALVACEAE. i ^ Cercocorpus-type. Prunus- type. Potentillo- fiti^yj-lype. BORAGINACEAE . SCROPHULARIACEAE. Rhu». CRUCIFER AE. Eriogonum. LABfA'rjf; ONAGRACEAE. Euphorbia. RANUNCULACEAE. Acacia. SAXIFRACEAE . PRIMULACEAE. Ceonothm-tvoe . Rhomnm, CARYOPHYLLACEAE. Agave. ERICACEAE. NYCTAGINACEAE. Arceuthobium. Plontooo. Undetermined. tie Unknown. Pellet Groups 2 1 1 2 1 2 2 1 2 1 1 1 1 2 2 1 1 2 1 1 N 390 260 390 393 130 260 260 130 264 260 260 260 130 260 260 260 130 390 130 130 Sample Interval 1 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22 e! 2% k20%4 h40%H Figure 4. Relative frequencies of entomophilous pollen from fecal pellets from Cow Camp Spring, Clark County, Nevada to Fecal pellets were collected semimonthly. "4 FLAHERTY SHELTER Diagram of Anemophilous Pollen DATES -230- 396 -390 -429- 543 -571 - -214 - -206- - 210 - - 205- • 163 - -1266- - 202- -345- -212 - 259- Scale: Figure 5. Relative frequencies of anemophilous pollen from samples from Flaherty Shelter Unit I, Clark County, Nevada Sample intervals were 2.5 cm. FLAHERTY SHELTER Diagram of Entomophilous Pollen Figure 6. Relative frequencies of entomophilous pollen from samples from Flaherty Shelter Unit I, Clark County, Nevada Sample intervals were 2.5 cm. 30 Wide, random fluctuations exhibited by certain pollen types in both the modern and fossil spectra are assumed to be evidence for in gestion while the plants were in flower. More undetermined and un known types (Benninghoff and Kapp 1962) toward the top of the fossil dung deposit indicate that there has been progressive deterioration from the top. This probably indicates that the deposit has been exposed for some tim e. Although minor trends are evident, there are no major changes in the fossil pollen frequencies. There is no evidence for a major cli matic change. Cheno-ams have progressively higher frequencies toward the top of the deposit, while Artemisia decreases. Arboreal types were more common near the top of the deposit. With the exception of Cercocarpus-type, all entomophilous types were either poorly represented or had repeated large oscillations, making them unsuitable for seasonal or climatic indicators. AP frequen cies were very low in both the modern and fossil samples with means of 2.01% and 5.85%, respectively. In most mule deer and fossil bighorn fecal pellets studied by Bartos (1972), AP was also poorly represented. Scrophulariaceae and Boraginaceae are common in the modern samples but not the fossil series. Malvaceae is abundant in the fossil samples but not in the modern fecal pellets. Figure 7 shows an undetermined, probably entomophilous pollen grain that only occurs in the top eight levels (0 to 20 cm) in Flaherty Shelter Unit I. Flaherty Shelter Stratigraphy As with most cave deposits, that in Flaherty Shelter is a com bination of organic and inorganic debris. The inorganic component is 31 A B Figure 7. Pollen grain, undetermined type 1 A. Optical cross section. B. High focus. Scale: 1 mm = 0.5p. 32 derived from roof fall and, to a lesser extent, from dust blown into the shelter. Dung, plant remains, bones, and pollen constitute most of the organic fraction. The fill in Flaherty Shelter was divided into three stratigraphic units on the basis of color, texture, and composition. A compacted layer of dung from 0 to 55 cm in depth is desig nated Unit I. It forms a hard, dark-brown floor that covers most of the shelter. Samples taken between 2.5 and 5.0 cm and between 47.5 and 50.0 cm yielded radiocarbon ages of 2,400 + 150 years B.P. and 6,950 + 320 years B .P., respectively. Few macro fossils were found in Unit I, although finely macerated plant debris from sheep dung is abundant (Fig. 8). Unit I grades conformably into Unit II. Unit II, extending from 55 to 70 cm, differs greatly in composi tion from Unit I. It is highly compacted, brown, and nearly devoid of any organic debris. Only two fecal pellets were found in this unit, prob ably contaminants from the unit above. Unit III extends from 70 cm to an unknown depth. Excavation was discontinued at 170 cm. It is similar in composition to Unit II but is unconsolidated and contains abundant macro fossils near the top. The quantity of these macrofossils decreases with increasing depth. Past climatic conditions can be inferred from the condition and amount of limestone debris in the shelter deposit. A lack of roof fall in Unit I contrasts with its abundance in Units II and in. Most of the frag ments are sharp, angular, uncorroded, and from 1 to 10 mm in size. These eboulis secs are usually the product of thermoclastic weathering of the roof and walls near the entrance to caves (Butzer 1964). Condi tions leading to thermoclastic weathering, primarily repeated temperature 33 Figure 8. Flaherty Shelter Unit I The tagged nails were driven into the deposit at 2 .5-cm inter vals for sampling control. 34 transitions across the freezing point, appear to have been prevalent dur ing the time Units II and III were laid down. This may have been during the late Pleistocene. Most of the organic remains in Unit III are younger than the bottom date for Unit I, 6950 + 320 years B.P. Some plant fragments still contain chlorophyll. Until a "roof" had been consolidated over Unit III, the looseness of the fill would have prevented rodents from carrying con taminants into the deposit. Most organic remains seem restricted to the top 50 cm of Unit III and are of plants that still occur in the area and are considered to be of Holocene age (Table 8). Unit II appears to have originally been an undifferentiated part of Unit III. When bighorn sheep began using the shelter, the upper 15 cm of cave earth was probably consolidated by trampling and urination, creating Unit II. The unconformity at the base of Unit II was then accen tuated by the activity of burrowing rodents. 35 Table 8. Plant fragments from Unit III, Flaherty Shelter Depth (cm) Species Type 70-80 Symphoricarpos long!floras seeds, twigs Sphaeralcia ambiqua carpel Chrysothamnus nauseosus seeds Festuca sp. inflorescence Rhus trilobate seeds, leaves Prunus fasciculate seed Pinus monophylla 1 seed Ephedra sp. seed 80 —90 Ephedra sp. seed Prunus fasciculate * seed Philadelphus sp. 1 leaf Rhus trilobate seeds, leaves 100-110 Symphoricarpos lonqiflorus seed s Lappula redowskii seed s Glossopetalon nevadense seeds Ephedra sp. seed s Tuniperus osteosperma 1 seed Prunus fasciculata seed 110-120 Tuniperus osteosperma 1 seed Rhus trilobata seed 120-130 Celtis reticulata * seed Symphoricarpos lonqiflorus fruit Glossopetalon nevadense seed 130-140 Symphoricarpos lonqiflorus fruit 140-150 Symphoricarpos lonqiflorus fruit Glossopetalon nevadense seed 1. Extralocal species. DISCUSSION Evidence that the dung in Flaherty Shelter is of the desert big horn is circumstantial. The only other large herbivore known in this area that produces fecal pellets of similar size is the mule deer (Odocoileus hemionus) . Mule deer do frequent the Sheep Range. However, there are no records of mule deer using caves and, in the shelter, no readily iden tifiable faunal material. All droppings collected are assumed to be from bighorn sheep. The Holocene Vegetation The differences between the vegetation at Cow Camp Spring and Flaherty Shelter is a function of interrelated edaphic and climatic vari ables. These variables determine what species will be able to exist in an area, their diversity and abundance. The most important variable in this study is slope exposure (aspect). The lack of insolation on the north-facing slope in front of Flaherty Shelter effectively reduces the transpirational stress undergone by plants and the evaporative water loss from the soil. The higher water content in the soil in turn promotes de composition of limestone and organic debris. Limestone is also reduced mechanically, by thermoclastic weathering. The deeper, finer grained soil encourages plant growth, further increasing its organic content and resistance to erosion. This feedback mechanism has a greater effect on the north-facing slope than on a south-facing slope or, like Cow Camp Spring, an exposed area. 36 37 An elevational difference of 300 m does not appear to affect the vegetation as much as does a difference in exposure. The lower site (Flaherty Shelter) has a more mesic plant assemblage (see Table 7). The effect of this difference on the relative pollen content of fecal pellets is probably minor. Bighorns can travel many miles in one day, passing through several vegetation zones. Relative frequencies of pollen in the dung of Nothrotheriops shastense. Oreamnos harringtoni. and Neotoma sp. from Rampart and Stanton's Caves in the Grand Canyon (Martin, Sabels and Shutler 1961) show the effect of late Pleistocene climatic change. However, I dis agree with their (1961, p. 107) assertion that anemophilous pollen does not reflect the diet of the herbivore and is therefore a useful tool in in terpreting climatic changes. The data accumulated by Bartos (1972) and by me seem to indicate otherwise. In the case of the desert bighorn, fluctuations of anemophilous pollen on a seasonal and random basis are so great as to render invalid any climatic interpretation based on them. This probably holds true for all large herbivores regardless of dietary h a b its . Vegetation change in the last 7,000 years may affect the results of this study. The fossil samples show a continued rise in the relative percentages of Cheno-am pollen toward the top of the deposit, accom panied by a decrease in Artemisia. This could be the pollen blown into the shelter and incorporated with the dung reflecting a slow trend from a coolor or wetter climate, or both, toward present conditions. Reliable data on the minor Holocene climatic fluctuations in the Great Basin or Mohave Desert is scarce. La Marche (1973), working 38 with bristlecone pine (Pious longaeva), has studied the middle to late Holocene history of fluctuating treeline in the White Mountains of east ern California. In a chronology spanning the last 7,000 years, several periods of warming and cooling are noticeable. Within the time spanned by the Flaherty Shelter deposit, the treeline shows a climatic optimum beginning about 5,000 years B.P. and lasting until between 3,500 and 3,000 years B.P. This period brackets a drop in AP and a rise in Gra- mineae in a pollen profile from O'Malley Shelter in Meadow Valley Wash, southeastern Nevada (Madsen 1973). There is a slight increase in AP beginning at the 15-cm level in Flaherty Shelter and continuing to the top. If deposition were con stant, this would be about 3,500 to 3,000 radiocarbon years ago. Un fortunately, this assumption cannot be made without comprehensive -^C c o n tro l. Desert Bighorn Behavior The behavior of the desert bighorn sheep may not be the same now as it was between 7,000 and 2,500 radiocarbon years ago. Seasonal food preferences vary over distance, between different races or sub species (Yoakum 1966). Since they vary over distance, they may also vary over time, both in response to environmental differences. Barrett (1964) found significant variation in the seasonal food habits of bighorns in the Sheep Range. Grasses (Gramineae) are the most important component of bighorn diet, averaging 76% throughout the year. The heaviest utilization of grasses is during the summer. Browse makes up 26% of the yearly diet and forbs 4%. During the spring and fall, forbs 39 exceed browse in importance. Artemisia tridentata, Cercocarpus intri- catus (little-leaf mountain mahogany), and Ephedra viridis are the most important browse species. Artemisia is particularly favored in the fall. Combining this information with the relative frequencies of four pollen taxa (Gramineae, Cheno-am, Ephedra nevadensis-type and Cercocarpus- type) and the known flowering period of species within these taxa, the prehistoric occupation of Flaherty Shelter appears to have been during the late spring and early summer. During the spring and early summer, modern fecal samples have • high relative frequencies of Cheno-am and Cercocarpus-type pollen. These pollen types are also abundant throughout most of the fossil pro file. The relative frequencies of Ephedra nevadensis-type are never very high in the fossil samples. However, that it is present in any quantity at all when its period of occurrence in the modern spectrum is so brief argues for a spring or early summer deposition of the fossil feces. The low relative percentages of Gramineae in the fossil material contrasts sharply with the modern spectrum, except during the spring and early summer. Since the utilization of grasses actually increases during this period (Barrett 1964), the drop in grass pollen percentages is probably an artifact of relative frequencies. With so many different species flower ing at this time, a higher amount of grass pollen may be masked by the total increase of all pollen types. A corollary of this assumption is that the total amount of pollen in the spring and summer feces is greater than that from the fall and winter. This pattern is true for modern mule deer pellets from Arizona (Bartos 1972). 40 Three of the seasonally indicative pollen taxa (Table 9) are composed of browse species (Deming 1964). The flowering periods of most of these species are coincident through the spring and early sum mer. It is during this period that the three pollen taxa surge in the mod ern pollen spectra. While there are undoubtedly other species involved, the species listed in Table 9 are the ones common in the area and most preferred by the bighorns (Barrett 1964). The known seasonal migratory habits of the desert bighorn sheep are in accord with a postulated spring and early summer occupation of Flaherty Shelter during prehistoric times. Hansen (1965) recognized the main routes followed by the bighorns in seasonal migrations across the Desert National Wildlife Range. In the fall, some bighorns leave the Cow Camp Spring area and winter in the vicinity of Gass Peak and Fossil Ridge (Figs. 1,9). They return to the Sheep Range in the spring, grad ually moving higher as the spring growth of grasses and other forage is found at increasing elevations (Deming 1964). The top date from Unit I (2,400 + 150 radiocarbon years B.P.) is essentially the same as the top date on bighorn pellets from Stanton's Cave, Grand Canyon, Arizona (Iberall 1972). Pellets from the 5- to 10- cm level yielded a radiocarbon age of 2,450 + 80 years B.P. (A-1165). The areas near both Flaherty Shelter and Stanton's Cave were frequented by prehistoric people. Numerous split-twig figurines were found in Stanton's Cave. Approximately 100 m east of Flaherty Shelter is an archaeological site in a rock shelter. Mescal pits near the site, numerous cones and seeds of the single-leaf pinyon, and agave quids indicate that the principal activities of the occupants were gathering 41 Table 9. Flowering periods of species included in the three pollen taxa used as seasonal indicators Mar Apr May Jun Jul Aug Sep Cercocarpus-type Cercocarpus intricatus 1 XX X Cercocarpus ledifolius 1 XX X Coleogyne ramosissima 1 XXX Cowania mexicana 1 X XX XXX Falluqia paradoxa X XX XX X Cheno-am Atrip lex canescens 1 XXX Eurotia lanata 2 X X XX X Ephedra nevadensis-type Ephedra nevadensis 2 X X Ephedra viridis 2 X X X 1. Data from Kearney and Peebles (1969). 2. Data from Munz (1959). 42 Figure 9. View south from the east side of the Sheep Range Across the Yucca Forest Valley is Fossil Ridge and beyond that Gass Peak and the Las Vegas Range. In the foreground is the plant as semblage on an exposed slope at 1,640-meter elevation. 43 pine nuts and harvesting the mescal (Agave utahensis). Several pinyon nuts have been found at Flaherty Shelter but none in a reliable strati graphic context. While the archaeological site was inhabited, the bighorn sheep would have been forced to avoid Flaherty Shelter. Habitation of the ar chaeological site may have been seasonal, in the fall when pinyons are in fruit. If this was the case, both Flaherty Shelter and the archaeolog ical site could have been occupied at the same time period, the bighorn sheep in the spring and the Indians in the fall. It is also possible that intensive prehistoric hunting over the last 2,500 years may have reduced bighorn populations in both the Sheep Range and the Grand Canyon. Fol lowing the historic decline of aboriginal populations, there may have been a resurgence of sheep populations in these areas. CONCLUSIONS 1. The occupation of Flaherty Shelter by the desert bighorn sheep was seasonal. Comparison of pollen from modern and fossil dung shows that the prehistoric use of the shelter was during the late spring or early summer, or both. 2. The relative frequencies of certain pollen types in desert big horn dung fluctuate seasonally. These seasonal fluctuations are dependent on the flowering periods of the various species constituting the pollen taxa. Relative frequencies of most pol len types fluctuate randomly and are caused by the dietary be havior of the bighorn. 3. Paleoclimatic interpretations based on herbivore dung are questionable for several reasons. First, the pollen in large- herbivore dung, on the whole, may not be representative of the plant community surrounding the site of deposition. Second, there are strong seasonal variations. Third, relative frequen cies of most types do fluctuate unpredictably. A major climatic change would probably show up in the pollen spectrum from herbivore feces. But, the potential of copropalynology to pro vide reliable data on the magnitude and effect of this change on the plant communities is limited. 4. Anemophilous pollen blown into Flaherty Shelter and not origi nally part of the dung appears to constitute a significant portion of the fossil pollen spectrum. Paleoclimatic interpretations 44 45 made in this study were based primarily on pollen derived from this source. 5. The gradual drop in the relative percentages of Artemisia toward the top of the deposit, accompanied by a rise in Cheno-am may indicate a slow trend toward increasing dry or warm conditions in southern Nevada. This apparent trend was still going on when deposition ceased, around 2,400 years ago. 6. The cessation of accumulation of sheep dung in Flaherty Shelter may have been due to the activities of prehistoric people in the a re a . APPENDIX POLLEN COUNTS AND RELATIVE FREQUENCIES 46 47 Pollen counts (PC) and relative percentages (RP) from Flaherty Shelter fecal samples, levels 1 through 7 Interval 1 Interval 2 Interval 3 Interval 4 Interval 5 Interval 6 Interval 7 Pollen Type PC RP PC RP PC RP PC RP PC RP PC RP PC RP Pinus 12 5 .2 1 13 4 .9 2 13 3 .9 0 33 8.33 8 2.06 7 1.79 13 3 .0 3 Junlpem s 4 1.74 9 3.41 6 1.8 0 15 4 .0 4 7 1 .8 0 9 2 .3 1 15 3 .5 0 Abies 5 1.2 6 2 0 .4 7 Q uercus 3 1.1 4 2 0 .6 0 4 1.01 1 0 .2 5 1 0 .2 6 Salix 4 1 .2 0 2 0 .5 1 1 0 .2 5 5 1 .2 8 C eltis 1 0 .2 5 1 0 .2 6 Corylus-type 1 0 .2 6 Gramineae 14 6.09 19 7 .2 0 11 3 .3 0 27 6 .8 2 19 4 .9 0 17 4 .3 6 29 6 .7 6 Ephedra nevadensis-type 15 6 .5 2 8 3.03 44 13.21 27 6 .8 2 41 1 0 .5 7 19 4 .8 7 30 6 .9 9 Ephedra torreyana-type 1 0 .3 8 1 0 .2 5 1 0 .2 5 1 0 .2 3 Short-spine Compositae 21 9.13 9 3 .4 1 11 3 .3 0 23 5 .8 1 34 8 .7 6 27 6 .9 2 31 7 .2 3 Artemisia 10 4 .3 5 20 7.58 9 2.70 35 8.84 20 5 .1 5 42 1 0 .7 7 53 1 2 .3 5 C heno-am s 56 2 4 .3 5 64 2 5 .2 4 67 2 0 .1 2 75 18.94 68 1 7 .5 3 92 2 3 .5 9 63 1 4 .6 9 Sarcobatus 2 0 .7 6 1 0 .2 5 1 0 .2 3 Long-spine Compositae 21 9 .1 3 14 5 .3 0 37 11.11 36 9 .0 9 49 1 2 .6 3 35 8 .9 7 65 1 5 .1 5 Liguliflorae Seneclo-tvpe M alvaceae 5 2 .1 7 6 2 .2 7 18 5 .4 1 9 2 .2 7 27 6 .9 6 51 1 3 .0 8 27 6 .2 9 Ccrcocarous-tvDe 20 8 .7 0 23 8 .7 1 35 10.51 27 6 .8 2 40 1 0 .3 1 20 5 .1 3 22 5 .1 3 Prunus-type 2 0 .7 6 3 0 .7 7 Potentilla-type Boraginaceae 2 0 .8 7 Scrophulariaceae Rhus •> 3 1.14 4 1.01 3 0 .7 7 2 0 .5 1 6 1 .4 0 Cruciferae 3 1 .3 0 5 1 .8 9 G llla 1 0 .2 6 5 1 .1 7 Other Polemoniaceae 3 0 .7 7 Eriorjonum 1 0 .4 3 1 0 .2 3 Yucca 1 0 .2 5 Labiatae 3 0 .9 0 1 0 .2 5 4 1 .0 3 2 0 .5 1 O nagraceae 2 0 .6 0 1 0 .2 6 2 0 .4 7 Euphorbia 1 0 .4 3 1 0 .3 8 Ranunculaceae 2 0 .8 7 S ola n a cea e 1 0 .4 3 1 0 .3 8 2 0 .6 0 A cacia Other Leguminosae 1 0 .4 3 1 0 .3 0 Symphoricarpos Saxifragaceae 10.26 Dodecatheon-type Ceanothus-type 1 0 .2 6 Opuntia-tvpe Undetermined type 1 2 0 .8 7 4 1 .2 0 2 0 .5 2 1 0 .2 6 1 0 .2 3 Other undertermined 14 6.09 16 6.06 32 9.61 21 5.30 11 2 .8 4 13 3 .3 3 18 4 .2 9 - 2 5 Unknown 1 0 .8 7 47 17.80 - 3 2 9 .6 1 — 12.37 44 11.34 _H 1 0 .5 1 -A! 1 0 .2 6 N 230 264 333 307 399 390 429 48 Pollen counts (PC) and relative percentages (RP) from Flaherty Shelter fecal samples, levels 8 through 14 Interval 8 Interval 9 Interval 10 Interval 11 Interval 12 Interval 13 Interval 14 Pollen Type PC RP PC RP PC RP PC - RP PC RP PC RP PC RP • Plnus 11 2 .0 2 10 1 .7 5 7 3 .2 7 9 4.37 10 4.76 3 1 .4 6 9 4 .9 2 Junlpcrus 5 0 .9 2 5 0 .8 8 7 3 .2 7 5 2 .4 3 6 2 .8 6 6 2 .9 3 Abies 2 0 .3 5 Q uercus 1 0 .4 8 S allx C e ltis 1 0 .1 8 Corylus-type Grarnlneae 11 2 .0 2 20 3 .5 0 9 4 .2 0 18 8 .7 4 9 4 .2 8 7 3 .4 1 8 4 .3 7 Ephedra nevadensls-type 29 5 .3 4 24 4 .2 0 15 7 .0 1 23 1 1 .1 6 9 4 .2 8 3 1 .4 6 5 2 .7 3 Ephedra torreyana-type 1 0 .4 8 Short-spine Composltae 20 3 .6 8 23 4 .0 3 8 3 .7 4 9 4 .3 7 8 3 .8 1 8 3 .9 0 8 4 .3 7 Artem isia 32 ' 5 .8 9 36 6 .3 0 . 14 6.54 22 10.68 30 1 4 .2 8 27 13.17 56 30.60 C h en o-am s 114 2 0 .9 9 113 1 9 .7 9 61 28.50 45 21.84 36 17.14 74 3 6 .1 0 52 2 8 .4 2 Sarcobatus 1 0 .1 8 1 0 .1 8 Long-spine Composltae 149 2 7 .4 4 175 3 0 .6 5 18 8 .4 1 15 7 .2 8 31 1 4 .7 6 22 1 0 .73 5 2 .7 3 Liguliflorae 1 0 .1 8 Senecio-type 2 0.35 1 0 .4 7 2 0 .9 8 1 0 .5 5 M alvaceae 9 1 .6 6 19 3 .3 3 7 3 .2 7 27 13.1 1 33 1 5 .7 1 10 4 .8 8 13 7 .1 0 C ercocarp u s-typ e 69 12.71 59 1 0 .3 3 33 1 5 .4 2 22 1 0 .6 8 19 9 .0 5 35 1 7 .0 7 14 7 .6 5 Prunus-type Potentllla-tvpe Boraginaceae 20.93 3 1 .4 3 Scrophulariaceae Rhus 3 0 .5 5 8 1 .4 0 C ruciferae 10 4 .6 7 1 0 .4 8 2 0 .9 5 G tlta 5 0 .9 2 3 0 .5 2 2 0 .9 7 1 0 .4 8 1 0 .4 8 Other Polemoniaceae 1 0 .1 8 Erioqonum 2 0 .3 7 2 0 .3 5 1 0 .4 8 1 0 .4 8 Y ucca 2 0 .3 7 1 0 .1 8 2 0 .9 7 Labiatae 4 0 .7 4 O nagraceae 1 0 .1 8 Euphorbia Ranunculaceae 3 1 .4 0 S o la n a cea e A cacia 1 0 .1 8 Other Legumlnosae Symphorlcarpos Saxifragaceae 5 2 .3 4 Dodccatheon-type Ceanothus-type Opuntla-type Undertcrmlned type 1 2 0 .1 8 Other undetermined 27 4 .9 7 17 2 .9 8 4 1 .8 8 3 1.43 1 0.55 Unknown 47 8 .6 6 47 8 .2 3 . 10 4 .6 7 ___7 3 .4 0 2 3.33 5 2.44 _10 5.46 N 543 571 214 206 210 205 183 49 Pollen counts (PC) and relative percentages (RP) from Flaherty Shelter fecal samples, levels 15 through 21 Interval 15 Interval 16 Interval 17 Interval 18 Interval 19 Interval 20 Interval 21 Pollen Type Plnus 0 .5 5 10 4 .9 5 2 .6 1 11 5 .1 4 2 .3 6 3 .1 9 0 .7 7 Junlperus 0.88 2 0 .9 9 5 2 .3 4 2 .3 6 1 .4 2 1 .5 4 A bies 0 .4 7 Q uercus 1 0 .3 9 S alix 0 .3 5 C eltls 0 .3 5 Corylus-type Gram lneae 25 1 .9 7 4 1 .9 8 31 8 .9 8 18 8 .4 1 27 1 2 .7 4 39 1 3 .8 3 4 1.5 4 Ephedra nevadensis-type 92 7 .2 7 11 5 .4 4 9 2 .6 1 9 4 .2 1 19 8 .9 6 30 10.64 Ephedra torreyana-type Short-spine Compositae 20 1 .5 8 3 1 .4 8 11 3 .1 9 11 5 .1 4 6 2 .8 3 34 1 2 .0 6 2 0 .7 7 Artemisia 46 3.63 20 9.90 59 17.10 38 17.76 26 1 2 .2 6 60 2 1 .2 8 9 3 .4 8 C heno-am 262 2 0 .7 0 17 8 .4 2 57 16.52 59 2 7 .5 7 32 1 5 .0 9 73 2 5 .8 9 12 4 .6 3 Sarcobatus 1 0 .5 0 2 0 .7 1 Long-spine Compositae 34 2 .6 8 74 3 6 .6 3 36 10.4 3 16 7 .4 8 15 7 .0 8 30 1 0 .6 4 44 1 6 .9 9 Liguliflorae 18 8 .9 1 4 1.5 4 Senecio-type 6 0 .4 7 9 4 .4 6 3 0 .8 7 1 0 .4 7 4 1.42 93 35.91 M alvaceae 661 5 2 .2 1 6 2 .9 7 90 2 6 .0 9 14 6 .5 4 9 4 .2 4 14 4 .9 7 Cercocarpus-type 31 2 .4 5 23 1 1 .3 9 9 2 .6 1 20 9 .3 5 47 2 2 .1 7 42 1 4 .8 9 36 1 3 .9 0 Prunus-type 1 0 .2 9 2 0 .9 3 1 0 .3 5 Potentilla-type 2 0 .1 6 Boraginaceae 2 0 .9 4 Scrophulariaceae 4 1.5 4 Rhus 1 0 .0 8 2 0 .9 3 C ruclferae 11 0 .8 7 2 0 .9 3 2 0 .9 4 2 0 .7 1 7 2 .7 0 C ilia 1 0 .0 8 3 0 .8 7 2 0 .7 1 Other Polemoniaceae 3 1 .4 8 Ericqonum 1 0 .0 8 1 0 .4 7 3 1 .0 6 3 1 .1 6 Y ucca 14 1 .1 2 1 0 .5 0 1 0 .2 9 1 0 .4 7 3 1 .0 6 Labiatae 1 0 .4 7 O nagraceae 3 0 .2 4 1 0 .4 7 Euphorbia 2 0 .5 8 1 0 .3 5 2 0 .7 7 Ranunculaceae S o la n a cea e A cacia Other Legumlnosae Symphorlcarpos 1 0 .2 9 Saxifragaceae Dodecatheon-type 1 0 .2 9 Ceanothus-type Opuntla-type 2 0 .7 1 Undetermined type 1 Other undetermined 1 0 .0 8 2 0 .5 8 2 0 .9 3 1 0.35 5 1.93 Unknown 40 3 .1 6 20 5 .8 0 5 2 .3 4 11 5 .1 9 24 3.51 _27 10.42 N 1266 202 345 214 212 382 259 50 Pollen counts (PC) and relative percentages (RP) from Cow Camp Spring fecal pellets, sampling intervals 1 through 6 Interval 1 Interval 2 Interval 3 Interval 4 Interval 5 Interval 6 Pollen Type PC RP PC RP PC RP PC RP PC RP PC RP Pinus 1 0 .2 6 3 1 .1 5 7 1 .7 9 1 0 .2 5 1 0 .7 7 Tunlperus 4 1.03 1 0 .3 8 2 0 .5 1 7 1 .7 8 Abies Q uercus S alix 1 0 .3 8 Morus 1 0 .2 6 G ram lneae 149 2 8 .2 0 126 48.46 78 20.00 29 7.38 1 0 .7 7 Ephedra nevadensis-type 2 0 .5 1 163 4 1 .4 8 73 5 6 .1 5 Ephedra torreyana-type 1 0 .2 5 Artemisia 18046.15 22 8 .4 6 84 21.54 17 4.36 Short-spine Composltae 1 0.38 19 4 .8 7 1 0 .2 5 1 0 .7 7 Cheno-am 7.2.69 90 2 3 .0 8 20 5 .0 9 Long-spine Composltae 37 9 .4 9 86 3 3 .0 8 57 1 4 .6 2 28 7 .1 3 2 1 .5 4 Liguliflorae 3 1 .1 5 Senecio-type M alvaceae 2 0 .5 1 2 0 .5 1 2 0 .5 1 7 5 .3 8 Cercocarpus-type 3 0 .7 7 2 0 .7 7 24 6 .1 5 87 2 2 .1 4 35 2 6 .9 2 Primus-type 3 0 .7 6 1 0 .7 7 Potentilla-type 1 0 .3 8 Rubus-type Boraginaceae 2 0 .5 1 Scrophulariaceae 1 0 .2 5 Rhus 8 2 .0 4 Cruciferae 2 0 .5 1 6 1 .5 4 2 0 .5 1 1 0 .7 7 Erioqonum 1 0 .3 8 Y ucca 1 0 .2 5 Labiatae O nagraceae Euphorbia 31.15 5 3 .8 5 Ranunculaceae A cacia Symphoracarpos Saxifragaceae 1 0 .3 8 Primulaceae Ceanothus-type Plantaqo 1 0 .5 1 Rhamnus Caryophyllaceae Agave Ericaceae Nyctaginaceae Arceuthobium Undetermined 4 1 .0 3 1 0 .3 8 11 2 .8 2 6 1 .5 3 2 1.5 4 Unknown _ 8 2 .0 5 ____ 0 .3 8 _ i 1 .0 3 3 .5 6 __ 1 0 .7 7 N 390 260 390 393 130 Pellet-groups 2 1 1 2 1 51 Pollen counts (PC) and relative percentages (RP) from Cow Camp Spring fecal pellets, sampling intervals 7 through 12 Interval 7 Interval 8 Interval 9 Interval 10 Interval 11 Interval 12 Pollen Type PC RP PC RP PC RP PC RP PC RP PC RP Finns 10 3 .8 5 3 1 .1 5 Juniperus 1 0.38 5 1.92 3 2.31 1 0 .3 8 Abies 1 0 .3 8 Ouercus 41.54 2 0 .7 7 S alix M om s G ram lneac 2 0 .7 7 20 7.69 14 10.77 63 2 4 .2 3 18 6 .9 2 Ephedra nevadensis-type 45 1 7 .3 1 26 1 0 .0 0 1 0 .3 8 Ephedra torreyana-type Artemisia 2 0.77 49 18.85 2 1.5 4 3 1 .1 5 4 1 .6 4 Short-spine Compositae 8 3 .0 8 1 0 .3 8 C heno-am 2 0 .7 7 12 4 .6 2 40 3 0 .7 7 106 4 0 .7 7 126 4 8 .4 6 Long-spine Compositae 7 2 .6 9 2 1.5 4 20 7 .6 9 6 2 .3 1 Liguliflorae Senecio-tvpe 9 3 .4 6 M alvaceae 2 0 .7 7 4 3 .0 8 3 1 .1 5 Cercocarpus-type 92 35.38 46 17.69 11 8 .4 6 45 17.31 5320.38 P m n u s-type Potentilla-type 1 0 .7 7 R ubus-type 1 0 .3 8 Boraginaceae 97 37.31 43 18.46 36 27.69 Scrophulariaceae 1 0 .3 8 Rhus 2 0 .7 7 C ruclferae 1 0 .3 8 3 1 .1 5 4 3 .0 8 Erioqonum 3 1 .1 5 Y ucca 1 0 .3 8 2 0 .7 7 Lablatae 1 0 .3 8 2 0 .7 7 8 3 .0 8 2 0 .7 7 Onagraceae 21.54 Euphorbia 1 0 .3 8 Ranunculaceae 4 1.5 4 8 3 .0 8 A cacia Symphoracarpos 1 0.38 Saxifragaceae Primulaceae Ceanothus-type l 0 .3 8 Plantaqo Rhamnus Caryophyllaceae 1 0 .3 8 Agave 1 0 .3 8 Ericaceae 1 0 .3 8 Nyctaglnaceae Arceuthobium Undetermined 7 2 .6 9 3 2 .3 1 3 1 .1 5 9 3 .4 6 Unknown 2 .6 9 _ i 3 .4 6 ___7 5 .3 8 ___7 2 .6 9 ____ _ 8 3 .0 8 N 260 260 130 260 260 Pellet-groups 2 2 1 2 1 52 Pollen counts (PC) and relative percentages (RP) from Cow Camp Spring fecal pellets, sampling intervals 13 through 18 Interval 13 Interval 14 Interval 15 Interval 16 Interval 17 Interval 18 Pollen Type PC PR PC PR PC PR PC PR PC PR PC PR Plnus 10 3 .8 5 4 1 .5 4 2 1.54 2 0 .7 7 2 0 .7 7 1 0 .3 8 Jimlperus 2 0 .7 7 3 2 .3 1 4 1 .5 4 2 0 .7 7 Abies 3 1 .1 5 1 0 .3 8 Q uercus 1 0 .3 8 1 0 .3 8 Salix Morns G ram lneae 4 1 .5 4 55 2 1 .1 5 76 5 8 .4 6 103 3 9 .6 2 112 4 3 .0 8 204 7 8 .4 6 Ephedra nevadensls-type 2 0 .7 7 1 0 .7 7 1 0 .3 8 Ephedra torreyana-type 1 0 .3 8 Artemisia 1 0 .3 8 10 3 .8 5 3 2 .3 1 4 1.5 4 80 3 0 .7 7 17 6 .5 4 Short-spine Compositae 3 1 .1 5 3 1 .1 5 2 0 .7 7 1 0 .3 8 C heno-am 113 4 3 .4 6 15 11.54 78 30.00 4 1.5 4 2 0 .7 7 Long-spine Compositae 51 1 9 .6 2 22 8 .4 6 19 14.62 30 11.54 33 1 2 .6 9 16 6 .1 5 Ligullflorae Senecio-type 1 0 .7 7 1 0 .3 8 M a lv a cea e 2 0 .7 7 6 2 .3 1 Cercocarpus-typ e 10 3 .8 5 14 5 .3 8 6 4 .6 2 11 4 .2 3 7 2 .6 9 1 0 .3 8 Prunus-type Potentllla-type 5 1 .9 2 R ubus-type Boraglnaceae Scrophularlaceae 166 6 3 .8 5 2 0 .7 7 Rhus C ruciferae 1 0 .3 8 3 1 .1 5 1 0 .3 8 2 0 .7 7 Erlogonum 4 1 .5 4 1 0 .3 8 Yucca 1 0 .3 8 Labiatae 1 0.77 1 0.38 O nagraceae Euphorbia 3 1 .1 5 1 0 .3 8 Ranunculaceae 2 0 .7 7 A cacia Symphorlcarpos Saxifragaceae 1 0 .3 8 Prlmulaceae 1 0 .3 8 1 0 .3 8 Ceanothus-type Plantago Rhamnus Caryophyllaceae Agave E ricaceae Nyctaginaccae 1 0 .3 8 Arceuthobium Undetermined 3 1 .1 5 9 3 .4 6 1 0 .7 7 6 2 .3 1 5 1 .9 2 1 0 .3 8 Unknown __9 3 .4 6 -JO 3 .8 5 _ 2 1.54 -20 3.85 _LL 4 .2 3 ___2 0 .7 7 N 260 260 130 260 260 260 Pellet-groups 1 1 1 2 2 1 53 Pollen counts (PC) and relative percentages (RP) from Cow Camp Spring fecal pellets, sampling intervals 19 through 22 Interval 19 Interval 20 Interval 21 Interval 22 Pollen Type PC PR PC PR PC PR PC PR Pinus 2 0.51 1 0.77 lunlperus 1 0 .7 7 Abies Q ucrcus S allx Morns Gramlneae 106 81.53 225 5 7 .6 9 87 6 6 .9 2 113 8 6 .9 2 Ephedra nevadensls-type Ephedra torreyana-type Artem isia 8 6 .1 5 24 6 .1 5 8 6 .1 5 5 3 .8 5 Short-spine Compositae 9 2 .3 1 1 0 .7 7 C heno-am 1 0 .2 6 8 6 .1 5 2 1 .5 4 Long-spine Compositae 11 8.46 33 8 .4 6 18 13.8 5 2 1 .5 4 Liguliflorae 7 1 .7 9 Senecio-type 1 0 .2 6 1 0 .7 7 M a lv a cea e 4 1 .0 2 3 2 .3 1 1 0 .7 7 Cercocarpus-type 2 0 .5 1 Prunus-type Potcntllla-type 5 1.92 1 0 .2 6 Rubus-ty p e Boraginaceae 1 0 .7 7 55 1 4 .1 0 Scrophulariaceae Rhus C ruciferae 2 0 .5 1 Erlogonum 1 0 .7 7 9 2 .3 1 Y ucca Labiatae O nagraceae 1 0 .7 7 Euphorbia Ranunculaceae A cacia 1 0 .7 7 Symphorlcarpos Saxifragaceae Primulaceae Ceanothus-type Plantago Rhamnus Caryophyllaceae Agave E ricaceae Nyctaginaceae 1 0 .7 7 Arccuthobium 1 0 .7 7 1 0 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