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Kenneth L. Cole

Publications and source records attributed to Kenneth L. Cole.

10 recordsLinked to original sources
USGS2017

A late Holocene paleoecological record from Torrey Pines State Reserve, California

Paleoenvironments of the Torrey Pines State Reserve were reconstructed from a 3600-yr core from Los Peñasquitos Lagoon using fossil pollen, spores, charcoal, chemical stratigraphy, particle size, and magnetic susceptibility. Late Holocene sediments were radiocarbon dated, while the historical sediments were dated using sediment chemistry, fossil pollen, and historical records. At 3600 yr B.P., the estuary was a brackish-water lagoon. By 2800 yr B.P., Poaceae (grass) pollen increased to high levels, suggesting that the rising level of the core site led to its colonization by Spartina foliosa (cord-grass), the lowest-elevation plant type within regional estuaries. An increase in pollen and spores of moisture-dependent species suggests a climate with more available moisture after 2600 yr B.P. This change is similar to that found 280 km to the north at 3250 yr B.P., implying that regional climate changes were time-transgressive from north to south. Increased postsettlement sediment input resulted from nineteenth-century land disturbances caused by grazing and fire. Sedimentation rates increased further in the twentieth century due to closure of the estuarine mouth. The endemic Pinus torreyana (Torrey pine) was present at the site throughout this 3600-yr interval but was less numerous prior to 2100 yr B.P. This history may have contributed to the low genetic diversity of this species.

Quaternary Research↗
USGS2017

50,000 years of vegetation and climate history on the Colorado Plateau, Utah and Arizona, USA

Sixty packrat middens were collected in Canyonlands and Grand Canyon National Parks, and these series include sites north of areas that produced previous detailed series from the Colorado Plateau. The exceptionally long time series obtained from each of three sites (> 48,000 14 C yr BP to present) include some of the oldest middens yet discovered. Most middens contain a typical late-Wisconsinan glaciation mixture of mesic and xeric taxa, evidence that plant species responded to climate change by range adjustments of elevational distribution based on individual criteria. Differences in elevational range from today for trees and shrubs ranged from no apparent change to as much as 1200 m difference. The oldest middens from Canyonlands NP, however, differ in containing strictly xeric assemblages, including middens incorporating needles of Arizona single-leaf pinyon, far north of its current distribution. Similar-aged middens from the eastern end of Grand Canyon NP contain plants more typical of glacial climates, but also contain fossils of one-seed juniper near its current northern limit in Arizona. Holocene middens reveal the development of modern vegetation assemblages on the Colorado Plateau, recording departures of mesic taxa from low elevation sites, and the arrival of modern dominant components much later.

Arizona, Utah↗
USGS2016

Identifying bird and reptile vulnerabilities to climate change in the southwestern United States

Current and future breeding ranges of 15 bird and 16 reptile species were modeled in the Southwestern United States. Rather than taking a broad-scale, vulnerability-assessment approach, we created a species distribution model (SDM) for each focal species incorporating climatic, landscape, and plant variables. Baseline climate (1940–2009) was characterized with Parameter-elevation Regressions on Independent Slopes Model (PRISM) data and future climate with global-circulation-model data under an A1B emission scenario. Climatic variables included monthly and seasonal temperature and precipitation; landscape variables included terrain ruggedness, soil type, and insolation; and plant variables included trees and shrubs commonly associated with a focal species. Not all species-distribution models contained a plant, but if they did, we included a built-in annual migration rate for more accurate plant-range projections in 2039 or 2099. We conducted a group meta-analysis to (1) determine how influential each variable class was when averaged across all species distribution models (birds or reptiles), and (2) identify the correlation among contemporary (2009) habitat fragmentation and biological attributes and future range projections (2039 or 2099). Projected changes in bird and reptile ranges varied widely among species, with one-third of the ranges predicted to expand and two-thirds predicted to contract. A group meta-analysis indicated that climatic variables were the most influential variable class when averaged across all models for both groups, followed by landscape and plant variables (birds), or plant and landscape variables (reptiles), respectively. The second part of the meta-analysis indicated that numerous contemporary habitat-fragmentation (for example, patch isolation) and biological-attribute (for example, clutch size, longevity) variables were significantly correlated with the magnitude of projected range changes for birds and reptiles. Patch isolation was a significant trans-specific driver of projected bird and reptile ranges, suggesting that strategic actions should focus on restoration and enhancement of habitat at local and regional scales to promote landscape connectivity and conservation of core areas.

Open-File Report↗
USGS2013

The biogeographic histories of Pinus edulis and Pinus monophylla over the last 50,000 years

Well-preserved pine needles found in fossil packrat middens document the biogeographic responses of pinyon pines to changing climates over the last 50,000 years. During the full glacial Wisconsinan (MIS2), Pinus monophylla (single-needle pinyon), Pinus edulis (Colorado pinyon), and P. edulis var. fallax (Arizona singleleaf pinyon) all grew along the southern portions of their current ranges. P. monophylla extended from the southern Sierra Nevada across the Mojave Desert to northwestern Arizona. P. edulis grew from northwestern Arizona across central Arizona to New Mexico and south to westernmost Texas. P. edulis var. fallax grew throughout what is now the Sonoran Desert of southern Arizona. Application of the modern climate requirements for these species suggest that winter precipitation at this time was at least 150% of modern, but also that summer precipitation may have been somewhat greater than today, at least at the northernmost end of the Gulf of California. During the Bølling and Allerød intervals P. edulis and P. edulis var. fallax quickly expanded northward over the Mogollon Rim of central Arizona into the Little Colorado River basin and northwestern Arizona. This northerly expansion of the fallax variety during the Allerød interval suggests that temperatures were warmer than most of the latest Wisconsinan and that summer precipitation was at least 120% of modern. After the rapid warming at the start of the Holocene (11.7 ka), P. monophylla and P. edulis populations were reduced in extent as their retreating southerly stands were not immediately replaced by expansion into cooler regions. These populations slowly expanded 300–500 km northward at rates between 20 and 60 m y −1 , reaching some of their current northern limits only within the last millennium. Increases in temperature expected over the next several hundred years will result in a similar reduction in populations unless this warming is ameliorated by favorable increases in precipitation. The consistent needle anatomy and distributions of the three types relative to each other suggest that there has been little evolutionary change discernible from these needles over at least the last 25,000 years.

Arizona, California, Colorado, Nevada, New Mexico,↗
USGS2011

Past and ongoing shifts in Joshua tree distribution support future modeled range contraction

The future distribution of the Joshua tree (Yucca brevifolia) is projected by combining a geostatistical analysis of 20th-century climates over its current range, future modeled climates, and paleoecological data showing its response to a past similar climate change. As climate rapidly warmed ;11 700 years ago, the range of Joshua tree contracted, leaving only the populations near what had been its northernmost limit. Its ability to spread northward into new suitable habitats after this time may have been inhibited by the somewhat earlier extinction of megafaunal dispersers, especially the Shasta ground sloth. We applied a model of climate suitability for Joshua tree, developed from its 20th-century range and climates, to future climates modeled through a set of six individual general circulation models (GCM) and one suite of 22 models for the late 21st century. All distribution data, observed climate data, and future GCM results were scaled to spatial grids of ;1 km and ;4 km in order to facilitate application within this topographically complex region. All of the models project the future elimination of Joshua tree throughout most of the southern portions of its current range. Although estimates of future monthly precipitation differ between the models, these changes are outweighed by large increases in temperature common to all the models. Only a few populations within the current range are predicted to be sustainable. Several models project significant potential future expansion into new areas beyond the current range, but the species' Historical and current rates of dispersal would seem to prevent natural expansion into these new areas. Several areas are predicted to be potential sites for relocation/ assisted migration. This project demonstrates how information from paleoecology and modern ecology can be integrated in order to understand ongoing processes and future distributions.

Ecological Applications↗
USGS2008

Prehistoric Packrats Piled Up Clues to Climate Change

Scientists from the U.S. Geological Survey and Northern Arizona University studying climate change in the Southwestern United States are getting a helping hand?or would that be paw??from prehistoric packrats. By hoarding parts of animals and plants, including seeds and leaves, in garbage piles or ?middens,? these bushy-tailed rodents preserved crucial ecological and environmental information about the past. From these middens, scientists are able to reconstruct plant communities and natural systems from as long ago as 50,000 years. The contents of middens allow scientists to understand how ecosystems responded to rapid, large-scale climate changes of the past. The insights gained from midden research could offer clues to future changes driven by rapid climate shifts.

Fact Sheet↗
USGS2006

Using packrat middens to assess how grazing influences vegetation change in Glen Canyon National Recreation Area, Utah

The fossil and sub-fossil plant macrofossils and pollen grains found in packrat middens can serve as important proxies for climate and vegetation change in the arid Southwestern United States. A new application for packrat midden research is in understanding post-settlement vegetation changes caused by the grazing of domesticated animals. This work examines a series of 27 middens from Glen Canyon National Recreation Area (GLCA), spanning from 995 yr BP to the present, which detail vegetation during the periods just prior to, and following, the introduction of domesticated grazers. By comparing middens deposited before and after the start of grazing by domesticated sheep and cattle, the effect on the native plant communities through time can be determined. This analysis of change through time is augmented by measurements of change through space by contrasting contemporaneous middens from nearby similar grazed and ungrazed sites. These comparisons are only made possible by the presence of inaccessible ungrazed areas surrounded by steep cliffs. Multivariate ordinations of the plant assemblages from packrat middens demonstrated that even though all middens were selected from similar geologic substrates, soils, and vegetation type, their primary variability was site-to-site. This suggests that selecting comparable grazed versus ungrazed study treatments would be difficult, and that two similar sites several kilometers apart should not be assumed to have been the same prior to grazing without pre-grazing data. But, the changes through time on grazed areas, as well as the differences between grazed and ungrazed areas in the diversity of certain taxonomic groups, both suggest that grazing by domesticated ungulates has had a noticeable effect on the vegetation. The changes seen through time suggested that grazing lowered the number of taxa recorded and lessened the pre-existing differences within sites, homogenizing the resultant plant associations. Late Holocene pre-settlement middens, and modern middens from ungrazed areas, contained more native grasses, skunkbush sumac (Rhus trilobata), blackbrush (Coleogyne ramosissima), winterfat (Krascheninnikovia lanata), Utah serviceberry (Amelanchier utahensis), and roundleaf buffaloberry (Shepherdia rotundifolia) than modern middens from grazed areas. Pollen data supported the macrofossil data, recording decreases in pollen of the goosefoot family (Chenopodiaceae), grass family (Poaceae), and globemallow (Sphaeralcea spp.) from pre- to post-settlement.

Utah↗
USGS2004

The Colorado Plateau: cultural, biological, and physical research

Stretching from the four corners of Arizona, New Mexico, Colorado, and Utah, the Colorado Plateau is a natural laboratory for a wide range of studies. This volume presents 23 original articles drawn from more than 100 research projects presented at the Sixth Biennial Conference of Research on the Colorado Plateau. This scientific gathering revolved around research, inventory, and monitoring of lands in the region. The book's contents cover management techniques for cultural, biological, and physical resources, representing collaborative efforts among federal, university, and private sector scientists and land managers. Chapters on cultural concerns cover benchmarks of modern southwestern anthropological knowledge, models of past human activity and impact of modern visitation at newly established national monuments, challenges in implementing the 1964 Wilderness Act, and opportunities for increased federal research on Native American lands. The section on biological resources comprises sixteen chapters, with coverage that ranges from mammalian biogeography to responses of elk at the urban-wildland interface. Additional biological studies include the effects of fire and grazing on vegetation; research on bald eagles at Grand Canyon and tracking wild turkeys using radio collars; and management of palentological resources. Two final chapters on physical resources consider a proposed rerouting of the Rio de Flag River in urban Flagstaff, Arizona, and an examination of past climate patterns over the Plateau, using stream flow records and tree ring data. In light of similarities in habitat and climate across the Colorado Plateau, techniques useful to particular management units have been found to be applicable in many locations. This volume highlights an abundance of research that will prove useful for all of those working in the region, as well as for others seeking comparative studies that integrate research into land management actions.

Utah;Colorado;Arizona;New Mexico↗
USGS1982

Use of packrat middens to determine rates of cliff retreat in the eastern Grand Canyon, Arizona

Packrat midden data can be used to calculate rates of cliff retreat by relating midden age to the distance between cliff face and midden. Regression analysis using 14 radiocarbon-dated packrat deposits from the Mississippian Redwall Limestone in the eastern Grand Canyon suggests that the Redwall has been retreating at an average rate of 0.45 m/10 3 14 C yr. This rate of cliff retreat, which is comparable to other cliff-retreat rates reported from arid environments, implies that the Colorado River cut through the Redwall Limestone in the vicinity of Horseshoe Mesa about 3.7 m.y. B.P.

Arizona↗