| Title | Bioclimatic changes recorded in Holocene soils at the Jornada Basin LTER site and Lincoln National Forest, southern New Mexico |
| Publication Type | Thesis |
| Year of Publication | 2008 |
| Authors | Cruz J |
| Number of Pages | 67 |
| Date Published | 2008 |
| University | New Mexico State University |
| City | Las Cruces, NM |
| Thesis Type | M.S. Thesis |
| Accession Number | JRN00492 |
| Keywords | bioclimate, carbon isotope ratios, climate change, dissertation, Jornada Basin, Lincoln National Forest, soils, Holocene, thesis |
| Abstract | In order to understand the impact humans are having on desertification, it is necessary to address the magnitude of natural cycles of climate change and how it drives the migration of dryland biomes. Paleoclimate studies are useful for obtaining information about natural cycles of climate-driven vegetation change. This paleoclimate study uses carbon isotopes (13C/12C) in Holocene soils to derive paleoclimate information about the movement of arid, semiarid, and subhumid bioclimatic boundaries along an elevational transect in southern NM. Soil profiles of limestone alluvium at four sites of increasing rainfall and decreasing temperature were analyzed for their stable carbon values in order to make inferences about bioclimatic changes (C3 versus C4 vegetation) during the Holocene. This paleoclimate record suggests that the arid site was dominated by C3 shrub vegetation for the last 4,000 years, the semiarid site by C4 grasslands for approximately the last 3,000 yrs, and the subhumid A site by C3 trees or C3 cool season grasses for the last 7,000 yrs. However, minor shifts in the relative proportions of C3 versus C4 vegetation did occur during these time periods. The implications of these findings are that there were no major changes in vegetation (biome movement) during the last 4,000 to 7,000 years this time period. Within each bioclimatic zone vegetation was similar to today's vegetation. Still, subtle changes in the isotopic record may reflect the climatic influences of the Medieval Warm Period and Little Ice Age. |
| URL | NMSU Branson Library call #: S 1999 .C88 2008 c.2 |
