Grazing effects on microtopography in a desert grassland

TitleGrazing effects on microtopography in a desert grassland
Publication TypeConference Paper
Year of Publication2002
AuthorsNash M.S., Jackson E., Whitford WG
Conference Name87th Annual Meeting, Ecological Society of America
Date PublishedAugust 4-9, 2002
Conference LocationTucson, AZ
ARIS Log Number139792
AbstractCoincident with a worldwide 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 aboveground and belowground 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.