Linking ecosystem scale vegetation change to shifts in carbon and water cycling: the consequences of widespread pi??on mortality in the Southwest

Litvak, Marcy Ellen¹ 

[1] University of New Mexico

关键词: carbon cycle dynamics;    Southwestern U.S.;    coniferous tree mortality;    biogeochemical cycling;    disturbance;   

DOI  :  10.2172/1088865
RP-ID  :  ER46506-1
PID  :  OSTI ID: 1088865

美国|英语

来源: SciTech Connect

【 摘 要 】

The southwestern United States experienced an extended drought from 1999-2002 which led to widespread coniferous tree mortality. Pi??on-juniper (PJ) woodlands, which occupy 24 million ha throughout the Southwest, were extremely vulnerable to this drought. An abrupt die-off of 40 to 95% of pi??on pine (Pinus edulis) and 2-25% of juniper (Juniperus monosperma) across 1.5 million ha triggered rapid and extensive changes in the structure of PJ woodlands with potentially large, yet unknown, consequences for ecosystem services and feedbacks between the carbon cycle and climate system. Given the spatial extent of PJ woodlands (3rd largest biome in the US) and climatic predictions of increased frequency and intensity of drought in the region, it is crucial to understand the consequences of these disturbances on regional carbon and energy dynamics, biogeochemical processes and atmospheric CO2. The overall objective of our research was to quantify what impact widespread mortality of pi??on trees has for carbon and water cycling in PJ woodlands. Our specific objectives for this proposal were: 1) Quantify the carbon, water and energy exchange trajectory after mortality in PJ woodlands; 2) Determine the mechanisms controlling the response and recovery of ecosystem production and respiration processes following large-scale pi??on mortality; 3) Use the relationships we measure between ecosystem structure and function PJ woodlands recover from mortality to scale the results of our study up to the regional scale.