Pleistocene Wood Rat Middens and Climatic Change in Mohave Desert: A Record of Juniper Woodlands

Abstract

Leafy twigs and seeds of juniper are abundant in nine ancient Neotoma middens discovered in low, arid, desert ranges devoid of junipers, near Frenchman Flat, Nevada. Existing vegetation is creosote bush and other desert shrubs. Twelve radiocarbon dates suggest that the middens were deposited between 7800 to more than 40,000 years ago. Dominance of Utah juniper and absence of pinyon pine in most deposits indicates a local Pleistocene woodland climate more arid than the usual pinyon-juniper climate.

Radioactive Waste Disposal in Thick Unsaturated Zones

“…At the Nevada Test Site, direct evidence for an increase in effective moisture (due to some combination of reduced temperature and increased rainfall) derives from classical studies of fossil pack rat (Neotoma sp.) middens by Wells and Jorgensen (34). They showed, as have others (35) for adjacent areas, that woodland xerophytic plants (for example, juniper) grew at altitudes as much as 600 m below their present lowest occurrences.…”

Distributional Affinities of Some Xerophilous Insects (Coleoptera, Lepidoptera) in Central California

“…If the composite distributions of all the deserticolous species found at Panoche are plotted geographically, a common pattern emerges (Figs. A Hypsothermal interval in the Great Basin and Mojave Desert is suggested by the absence of pinyon-juniper woodland from mountain ranges of sufficient elevation to support such 314 woodland at the present time (Wells and Jorgensen, 1964). Most of the species are apparently distributed more or less continuously across the southern end of the valley from the Tehachapi Mountains to the Temblor Range, and then north to the Kettleman Hills, near Avenal, Kings County.…”

A tale of two species: Extirpation and range expansion during the late Quaternary in an extreme environment

“…The documentary quality is high because the amberat leads to long-term preservation of organic materials, including DNA. Examination of plant macrofossils recovered from paleomiddens has allowed reconstruction of the vegetation history of the southwestern United States over the late Quaternary (e.g., Wells and Jorgensen, 1964;Wells, 1966Wells, , 1976Wells and Berger, 1967;Van Devender, 1977, 1987Betancourt and Van Devender, 1981;Betancourt et al, 2001;Van Devender et al, 1985;Betancourt et al, 1990). However, the fossilized pellets contained within the middens also yield valuable information.…”