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Paleoclimate Estimates From The Late Cretaceous San Juan Basin Using Leaf Physiognomy., Frederick Vogt
Paleoclimate Estimates From The Late Cretaceous San Juan Basin Using Leaf Physiognomy., Frederick Vogt
Student Work
Physiognomy of fossil leaves collected from Late Cretaceous floodplain sediments in present-day northwestern New Mexico was used to estimate paleoclimate. Woody dicot species were collected from this area to determine the Mean Annual Temperature (MAT) and Mean Annual Precipitation (MAP) using both uni- and multi-variate methods. From the same stratigraphic level at the contact between the upper Fruitland and lower Kirtland Formations, 188 specimens from three sites representing twenty-five morphotypes were sampled. Specimens were plotted on a collection curve to ensure species numbers approached saturation during sampling. Leaf margin analysis, a technique that compares the percentage of entire margin to …
Ecological Conditions Of The Papillion Creek Watershed: Effects Of Adjacent Land-Use., Pamela D. Cox
Ecological Conditions Of The Papillion Creek Watershed: Effects Of Adjacent Land-Use., Pamela D. Cox
Student Work
Stream conditions were assessed for past and present landscapes of the Papillion Creek Watershed of northwest Omaha, Nebraska based on historical records, present land-use surveys and field data collected in June 2000 using the Environmental Protection Agency’s Rapid Bioassessment Protocol modified to meet the needs of the study. Less than 0.4% of the historic tallgrass Prairie remains, with the present landscape mostly in agriculture (83%) or residential-commercial developments (16%). No significant differences (P ≤ 0.05) were found between ten habitat parameters measured for each of three land-used categories, cultivated, residential-commercial, and other. The overall impact of increased land-use on the …