Late Wisconsin Macrofossil Records of Desert Vegetation in the American Southwest

AbstractUntil recently, the oldest-known packrat (Neotoma spp.) midden records of desert scrub vegetation were less than 10,500 yr old and were restricted to altitudes below 300 m in the northern Sonoran Desert. Recent discovery of macrofossil assemblages in the Mojave Desert extends the record of desert vegetation back to 14,800 yr ago and to altitudes as high as 910 m. Although xerophytic conifer woodland was widespread in current desert habitats during the Late Wisconsin and early Holocene, the development of extensive desert vegetation was not delayed until the beginning of the middle Holocene. A regional vegetation mosaic of desert scrub and woodland existed at altitudes below 1000 m in the Mojave Desert during the last part of the Late Wisconsin.

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Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American southwest

Endangered Species Research ◽

10.3354/esr01045 ◽

2020 ◽

Vol 42 ◽

pp. 167-184

Author(s):

SK Carter ◽

KE Nussear ◽

TC Esque ◽

IIF Leinwand ◽

E Masters ◽

...

Keyword(s):

Sonoran Desert ◽

Mojave Desert ◽

Spatial Scales ◽

Public Lands ◽

American Southwest ◽

Federal State ◽

Desert Tortoise ◽

Multiple Use ◽

State And Local ◽

Development Levels

Two tortoise species native to the American southwest have experienced significant habitat loss from development and are vulnerable to ongoing threats associated with continued development. Mojave desert tortoises Gopherus agassizii are listed as threatened under the US Endangered Species Act, and Sonoran desert tortoises G. morafkai are protected in Arizona (USA) and Mexico. Substantial habitat for both species occurs on multiple-use public lands, where development associated with traditional and renewable energy production, recreation, and other activities is likely to continue. Our goal was to quantify development to inform and evaluate actions implemented to protect and manage desert tortoise habitat. We quantified a landscape-level index of development across the Mojave and Sonoran desert tortoise ranges using models of potential habitat for each species (152485 total observations). We used 13 years of Mojave desert tortoise monitoring data (4732 observations) to inform the levels and spatial scales at which tortoises may be affected by development. Most (66-70%) desert tortoise habitat has some development within 1 km. Development levels on desert tortoise habitat are lower inside versus outside areas protected by actions at national, state, and local levels, suggesting that protection efforts may be having the desired effects and providing a needed baseline for future effectiveness evaluations. Of the relatively undeveloped desert tortoise habitat, 43% (74030 km2) occurs outside of existing protections. These lands are managed by multiple federal, state, and local entities and private landowners, and may provide opportunities for future land acquisition or protection, including as mitigation for energy development on public lands.

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Late Quaternary Lacustrine History and Paleoclimatic Significance of Pluvial Lake Cochise, Southeastern Arizona

Quaternary Research ◽

10.1016/0033-5894(89)90027-6 ◽

1989 ◽

Vol 32 (1) ◽

pp. 1-11 ◽

Cited By ~ 79

Author(s):

Michael R. Waters

Keyword(s):

Late Quaternary ◽

American Southwest ◽

Early Holocene ◽

Central Portion ◽

Ancient Lake ◽

The Holocene ◽

Middle Holocene ◽

Ephemeral Lakes ◽

Independent Evaluation ◽

Paleoclimatic Significance

AbstractDuring the latest Quaternary, freshwater pluvial lakes intermittently formed in the topographically closed Willcox basin, Arizona. A lacustrine sequence of six separate high stands of Lake Cochise is documented by stratigraphic studies, 19 radiocarbon ages, and supplementary evidence. Two stands of pluvial Lake Cochise, older than 14,000 yr B.P., reached elevations above 1290 m. The prominent 1274-m shoreline of Lake Cochise, which circumscribes the basin, was largely created during a high stand between 13,750 and 13,400 yr B.P. During the Holocene, water filled the Willcox basin three times to an elevation slightly below the crest of the 1274-m shoreline. This occurred once during the early Holocene around or before 8900 yr B.P. and twice during the later part of the middle Holocene. Since the middle Holocene, only shallow ephemeral lakes have occupied the deflated central portion of ancient Lake Cochise, a depression known as the Willcox Playa. The lacustrine sequence of Lake Cochise provides an independent evaluation of late Quaternary paleoclimatic reconstructions for southern Arizona and the American Southwest.

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Shutting down dust emission during the middle Holocene drought in the Sonoran Desert, Arizona, USA

Geology ◽

10.1130/g48550.1 ◽

2021 ◽

Author(s):

Guy Tau ◽

Onn Crouvi ◽

Yehouda Enzel ◽

Nadya Teutsch ◽

Paul Ginoux ◽

...

Keyword(s):

Sonoran Desert ◽

Mojave Desert ◽

Vegetation Change ◽

Dust Emission ◽

Major Elements ◽

Sediment Supply ◽

Transport Pathways ◽

Middle Holocene ◽

Dust Sources ◽

Montezuma Well

Long-term relationships between climate and dust emission remain unclear, with two prevailing but opposite hypotheses for effects of climate shifts: (1) increased dust emission due to increasing aridity imposing a vegetation change, or (2) decreased dust emission due to increasing aridity which imposes less stormy climate and reduced sediment supply. Here we test these hypotheses by analyzing an ~11-m-long core archiving Holocene dust trapped in Montezuma Well, a natural sinkhole in Arizona (southwestern United States), alongside current dust sources and transport pathways. Major elements indicate that Montezuma Well sediments originate from two end members: local carbonate bedrock and external siliceous dust. Core sediments are similar to the adjacent siliceous soils accumulated atop the bedrock, pointing to their eolian origin. Particle-size distributions reveal fine dust transported during winter from the northwestern Sonoran Desert and the Mojave Desert and coarse dust transported during summer from the southwestern Sonoran Desert, similar to current climate systems and dust pathways. A survey of potential dust sources indicates that current summer and winter dust sources in the Sonoran Desert are under a supply-limited state. Dust fluxes were higher during wetter phases of the Holocene when winter sources dominated. During the middle Holocene drought, dust fluxes were minimal and dominated by summer sources until dust input ceased as drought conditions did not produce enough floods to refill sources with sediments. We propose that in the Sonoran Desert, dust emission is strongly connected with climate, increasing during humid intervals and enhanced by fluvial sediment replenishment at dust sources.

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Late Pleistocene to Middle Holocene Archaeology in the Mojave Desert: Recent Discoveries in Twentynine Palms, California

PaleoAmerica ◽

10.1179/2055556315z.00000000020 ◽

2015 ◽

Vol 1 (2) ◽

pp. 197-201

Author(s):

Ryan M. Byerly ◽

Joanna C. Roberson

Keyword(s):

Late Pleistocene ◽

Mojave Desert ◽

Middle Holocene

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Allometry of unifacial flake tools from Mojave Desert terminal pliestocene/early holocene sites: Implications for landscape knowledge, tool design, and land use

Journal of Archaeological Science Reports ◽

10.1016/j.jasrep.2021.103314 ◽

2022 ◽

Vol 41 ◽

pp. 103314

Author(s):

Edward J. Knell

Keyword(s):

Land Use ◽

Mojave Desert ◽

Tool Design ◽

Early Holocene

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Alteration of tropical forest vegetation from the Pleistocene–Holocene transition and plant cultivation from the end of early Holocene through middle Holocene in Northwest Colombia

Quaternary International ◽

10.1016/j.quaint.2014.09.018 ◽

2015 ◽

Vol 363 ◽

pp. 28-42 ◽

Cited By ~ 11

Author(s):

Gustavo Santos Vecino ◽

Carlos Albeiro Monsalve Marín ◽

Luz Victoria Correa Salas

Keyword(s):

Tropical Forest ◽

Forest Vegetation ◽

Early Holocene ◽

Middle Holocene ◽

Plant Cultivation

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Radiocarbon Variations from Tasmanian Conifers: Results from Three Early Holocene Logs

Radiocarbon ◽

10.1017/s0033822200030836 ◽

1995 ◽

Vol 37 (2) ◽

pp. 361-369 ◽

Cited By ~ 14

Author(s):

Mike Barbetti ◽

Trevor Bird ◽

George Dolezal ◽

Gillian Taylor ◽

Roger Francey ◽

...

Keyword(s):

Southern Hemisphere ◽

Calibration Curve ◽

The Other ◽

Early Holocene ◽

Conifer Species ◽

Middle Holocene ◽

Calibration Curves ◽

Lagarostrobos Franklinii ◽

Floodplain Sediments ◽

Good Coverage

Dendrochronological studies are being carried out on two conifer species in the Stanley River area of western Tasmania. The chronology for Huon pine (Lagarostrobos franklinii), with living trees up to 1400 yr old, extends back to 571 bc. Living celery-top pine (Phyllocladus aspleniifolius) trees are up to 500 yr old. Apart from living or recently felled trees, sections have been taken from 350 subfossil logs preserved in floodplain sediments. They range in age from >38 ka to modern, with good coverage for the periods 9–3.5 ka and from 2.5 ka to the present. We report here on 14C measurements of decadal samples from three early Holocene logs, between 10 and 9 ka bp, providing short (ca. 300-yr) records of atmospheric 14C variations when plotted against ring numbers. The southern hemisphere data from Tasmania can be compared and wiggle-matched with published 14C calibration curves from German oak and pine. One set of measurements covers the period, ca. 9280–8990 cal bp, overlapping the link between the Hohenheim “Main 9” and middle Holocene master oak chronologies. The other sets of measurements from Tasmania coincide; they span the period, ca. 9840–9480 cal bp, overlapping the end of the German Preboreal pine and the beginning of the oak chronologies. Our measurements confirm that this part of the calibration curve is a gently sloping 14C-age plateau (ca. 8900–8700 bp, between 10,000 and 9500 cal bp), and suggest interhemispheric 14C differences close to zero.

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Temporal partitioning and the effects of climate change on two ecologically similar desert bats

Journal of Mammalogy ◽

10.1093/jmammal/gyy113 ◽

2018 ◽

Vol 99 (6) ◽

pp. 1486-1494

Author(s):

Connor T Lambert ◽

Lucas K Hall ◽

Randy T Larsen ◽

Robert N Knight ◽

Brock R McMillan

Keyword(s):

Climate Change ◽

Surface Area ◽

Mojave Desert ◽

Free Water ◽

Limited Resource ◽

Water Sources ◽

American Southwest ◽

Temporal Partitioning ◽

Bat Activity ◽

Drinking Behaviors

Abstract Climate change is predicted to create increasingly arid deserts with fewer and smaller water sources. Because free water is already limiting for arid-adapted animals, reductions in water likely will impact desert species and how they compete for this limited resource. Our objective was to examine how the size of water sources influenced competition between 2 ecologically similar bats, Parastrellus hesperus and Myotis californicus, in the American Southwest. Bats are a highly successful taxon in deserts, although many rely upon access to free water. We examined bat activity observationally over 35 different-sized water sources throughout the Mojave Desert in southwestern Utah, United States, and experimentally reduced the surface area of 2 water sources. Parastrellus hesperus and M. californicus typically occurred at the same water sources, but both species temporally partitioned their use of shared water sources regardless of the surface area of the water. Experimentally reducing surface area of water sources negatively affected drinking behaviors of both species and resulted in higher overall activity, but temporal partitioning still occurred. While loss of water may influence some competitive interactions, mechanisms such as temporal partitioning can potentially allow continued co-use of limited resources by competing species.

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