PARENT SESSION
Oral Session #40: Carbon sequestration and flux.
Presiding: G. Koch
Tuesday, August 6. 1:00 PM to 4:45 PM. Gila Meeting Room, TCC.
Long term changes in carbon pools accompanying shrub invasion of a desert grassland: The Jornada Experimental Range 1850 - today.
Mitchell, Katherine*,1, Peters, Debra1, Herrick, Jeffrey1, Monger, Curtis2, 1 USDA-ARS, Jornada Experimental Range, Las Cruces, NM, kathmitc@nmsu.edu2 New Mexico State University, Las Cruces, NM
ABSTRACT- Coincident with a world-wide increase in the abundance of woody plants within former grasslands, desert grasslands throughout the southwestern U.S. have experienced a substantial increase in the abundance of shrubs during the last century. The displacement of grasslands with grass-shrublands has had important implications for ecosystem carbon cycling and rates of carbon sequestration. Building on a history of biogeochemistry research conducted at the Jornada Experimental Range in southern New Mexico, we measured and modelled above and below-ground carbon storage in black grama grasslands (Bouteloua eriopoda) , and mesquite (Prosopis glandulosa) and creosotebush (Larrea tridentata) shrublands, across the Jornada basin. We combined the simulation modeling predictions of the CENTURY model with data from recovered historical vegetation maps of 1858, 1915, 1928 and modern vegetation maps. Our results support the hypothesis that shrub encroachment into grasslands increases storage of belowground carbon. Landscape-level mapped estimates of carbon pools indicate that the desert grassland ecosystem of the Jornada basin may have served as a carbon sink during the last century.
KEY WORDS: carbon, CENTURY, chihuahuan desert, woody encroachment