The Diamond Valley Lake fauna is the largest open, non-asphaltic late Pleistocene assemblage known from the American southwest. A classic suite of Rancholabrean vertebrates characterizes the fauna, which includes nearly 100,000 identifiable fossils representing more than 105 vertebrate, invertebrate, and plant taxa from 2646 localities. Because of the volume, diversity, and excellent preservation of fossils recovered, this assemblage warrants designation as a local fauna. Located within the northern Peninsular Range physiographic province of southern California, the Diamond and Domenigoni Valleys are bounded by bedrock highlands and form a contiguous east-west drained trough, 9 km long and 2.5 km wide. The alluvium-filled valleys contain bedded silts and clays intercalated with coarse-grained channel fill representing a braided stream environment, which yielded AMS dates from ~19 ka to ~13 ka. These fluvial sediments unconformably truncate silts, clays and an organic black clay at depth. The clay is lacustrine in origin, with AMS dates from ~46 ka to ~41 ka. Both of these distinct sediment packages yielded abundant vertebrate remains; the lacustrine sediments produced a rare floral assemblage, as well. The relative abundance of Bison and Equus in the fauna resembles that reported from Rancho La Brea, while representation of Camelops approximates that from Mojave Desert localities. The rare co-occurrence of Paramylodon harlani, Megalonyx jeffersonii, and Nothrotheriops shastensis is also notable. Remains of Mammut americanum are abundant, far more so than at any other regional late Pleistocene site, and include very large individuals compared to other mastodons in the American West. Large carnivorans are rare, suggesting an unbiased distribution for the sample population. Pollen data indicate grassland, scrub, chaparral, forest, and riparian communities present in older sediments, while younger fluvial sediments suggest a forest/chaparral mosaic.

These contributed papers review the current status of plant conservation in the southwestern U.S.

The Phoenix talussnail was detected at 16 new localities, bringing the total to 20 within the greater Phoenix metropolitan area of northeastern Maricopa County. The species was detected within discontinuous ranges of central and north Phoenix, Scottsdale, Fountain Hills, Glendale, Peoria, Cave Creek, Carefree, and New River. Snails inhabit hillside talus and rocky desert washes. Within appropriate talus habitat, formed by dense igneous and metamorphosed bedrock, snails were detected on all slope aspects and only when slope gradient was minimally 18º, or 32%. Snails were not evenly detected throughout talus where present, nor were they always detected on neighboring hills with appropriate habitat. Snail surface activity periodically occurs after rainfall from December through March when surface temperatures range from 7°C–15°C and soil moisture is greater than 60%. Summer surface activity, following monsoon rainfall from July to September, was not detected in 2011 but has been reported in the past during wet years. Snails were observed estivating during dry hot periods on average 0.37 m below the surface. Summer temperatures at this depth average 34°C. Snails were tested on a thermal gradient and found to avoid temperatures < 1°C and > 34ºC. Snails perished rapidly at or below 0ºC. Upper estivation thermal limits are unknown. The introduced decollate snail, a predator of snails and slugs, was not detected at any sample sites. Introduced buffelgrass was detected and poses a significant threat to talus habitat. Hillside talus is well conserved within the greater Phoenix metropolitan area and there do not appear to be any significant threats to talus via development or mining. Washes have been heavily altered throughout the valley and continue to be modified due to ongoing, rapid development near mountains. Substantial areas of talus habitat are unoccupied by the species and the extent of wash occupancy is unknown. To reduce the danger of wildfire impacts to talus slopes, exotic fire-tolerant buffelgrass needs to be controlled. Further study is recommended to determine whether widely separated talussnail populations are genetically distinct or cryptic species, and whether their populations are stable or in decline. Additional research is needed to determine habitat correlates of occupied washes, whether washes are suitable for dispersal, and to determine the critical thermal and moisture parameters the species requires of its microhabitat at sensitive life stages.

A thick alluvial sequence in central New Mexico contains the Scholle wet meadow deposit that traces upstream to a paleospring. The wet meadow sediments contain an abundant fauna of twenty-one species of freshwater and terrestrial mollusks and ten species of ostracodes. The mollusks and ostracodes are indicative of a local high alluvial water table with spring-supported perennial flow but without standing water. Pollen analysis documents shrub grassland vegetation with sedges, willow, and alder in a riparian community. Stable carbon isotopes from the wet meadow sediments have δ13C values ranging from − 22.8 to − 23.3‰, indicating that 80% of the organic carbon in the sediment is derived from C3 species. The wet meadow deposit is AMS dated 10,400 to 9700 14C yr BP, corresponding to 12,300 to 11,100 cal yr BP and overlapping in time with the Younger Dryas event (YD). The wet meadow became active about 500 yr after the beginning of the YD and persisted 400 yr after the YD ended. The Scholle wet meadow is the only record of perennial flow and high water table conditions in the Abo Arroyo drainage basin during the past 13 ka.