Consequences of Cool-Season Drought-Induced Plant Mortality to Chihuahuan Desert Grassland Ecosystem and Soil Respiration Dynamics

Erik P. Hamerlynck, Russell L. Scott, Greg A Barron-Gafford

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Predicted reductions of cool-season rainfall may expand and accelerate drought-induced plant mortality currently unfolding across the Southwest US. To assess how repeated plant mortality affects ecosystem functional attributes, we quantified net ecosystem CO2 exchange (NEE), ecosystem respiration (R eco), and gross ecosystem photosynthesis (GEP) responses to precipitation (P) at a semidesert grassland over spring (Feb 1-Apr 30) and summer (June 15-Oct 1) plant-active periods across eight years, including two with distinct patterns of extensive species-specific mortality. In addition, we quantified daily soil respiration (R soil) in high- (56-88%) and low-mortality (8-27%) plots the summer following the most recent mortality event. Plant mortality coincided with severely dry cool-season conditions (Dec 1-Apr 30). We found a positive relationship between springtime P and GEP, and that springtime conditions influenced GEP response to summer rainfall. High springtime R eco/GEP ratios followed plant mortality, suggesting increased available carbon after mortality was rapidly decomposed. R soil in low-mortality plots exceeded high-mortality plots over drier summer periods, likely from more root respiration. However, total cumulative R soil did not differ between plots, as variation in surviving plant conditions resulted in high and low C-yielding plots within both plot types. Vegetation status in high C-yielding R soil plots was similar to that across the grassland, suggesting R soil from such areas underlay higher R eco. This, coupled to springtime drought constraints to GEP, resulted in positive NEE under summer P accumulations that previously supported C-sink activity. These findings indicate that predicted lower cool-season precipitation may strongly and negatively affect summer season productivity in these semiarid grasslands.

Original languageEnglish (US)
Pages (from-to)1178-1191
Number of pages14
JournalEcosystems
Volume16
Issue number7
DOIs
StatePublished - Nov 2013

Fingerprint

Chihuahuan Desert
desert soil
ecosystem respiration
grassland soil
Drought
soil respiration
Ecosystems
grasslands
drought
Soils
Photosynthesis
mortality
ecosystem
ecosystems
photosynthesis
summer
grassland
soil
Rain
respiration

Keywords

  • climate change
  • ecosystem respiration
  • gross ecosystem photosynthesis
  • net ecosystem carbon dioxide exchange
  • seasonal precipitation
  • soil moisture
  • southern oscillation/El Niño

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Environmental Chemistry

Cite this

Consequences of Cool-Season Drought-Induced Plant Mortality to Chihuahuan Desert Grassland Ecosystem and Soil Respiration Dynamics. / Hamerlynck, Erik P.; Scott, Russell L.; Barron-Gafford, Greg A.

In: Ecosystems, Vol. 16, No. 7, 11.2013, p. 1178-1191.

Research output: Contribution to journalArticle

@article{10a4b753c9814b1eba1a3c89793774d6,
title = "Consequences of Cool-Season Drought-Induced Plant Mortality to Chihuahuan Desert Grassland Ecosystem and Soil Respiration Dynamics",
abstract = "Predicted reductions of cool-season rainfall may expand and accelerate drought-induced plant mortality currently unfolding across the Southwest US. To assess how repeated plant mortality affects ecosystem functional attributes, we quantified net ecosystem CO2 exchange (NEE), ecosystem respiration (R eco), and gross ecosystem photosynthesis (GEP) responses to precipitation (P) at a semidesert grassland over spring (Feb 1-Apr 30) and summer (June 15-Oct 1) plant-active periods across eight years, including two with distinct patterns of extensive species-specific mortality. In addition, we quantified daily soil respiration (R soil) in high- (56-88{\%}) and low-mortality (8-27{\%}) plots the summer following the most recent mortality event. Plant mortality coincided with severely dry cool-season conditions (Dec 1-Apr 30). We found a positive relationship between springtime P and GEP, and that springtime conditions influenced GEP response to summer rainfall. High springtime R eco/GEP ratios followed plant mortality, suggesting increased available carbon after mortality was rapidly decomposed. R soil in low-mortality plots exceeded high-mortality plots over drier summer periods, likely from more root respiration. However, total cumulative R soil did not differ between plots, as variation in surviving plant conditions resulted in high and low C-yielding plots within both plot types. Vegetation status in high C-yielding R soil plots was similar to that across the grassland, suggesting R soil from such areas underlay higher R eco. This, coupled to springtime drought constraints to GEP, resulted in positive NEE under summer P accumulations that previously supported C-sink activity. These findings indicate that predicted lower cool-season precipitation may strongly and negatively affect summer season productivity in these semiarid grasslands.",
keywords = "climate change, ecosystem respiration, gross ecosystem photosynthesis, net ecosystem carbon dioxide exchange, seasonal precipitation, soil moisture, southern oscillation/El Ni{\~n}o",
author = "Hamerlynck, {Erik P.} and Scott, {Russell L.} and Barron-Gafford, {Greg A}",
year = "2013",
month = "11",
doi = "10.1007/s10021-013-9675-y",
language = "English (US)",
volume = "16",
pages = "1178--1191",
journal = "Ecosystems",
issn = "1432-9840",
publisher = "Springer New York",
number = "7",

}

TY - JOUR

T1 - Consequences of Cool-Season Drought-Induced Plant Mortality to Chihuahuan Desert Grassland Ecosystem and Soil Respiration Dynamics

AU - Hamerlynck, Erik P.

AU - Scott, Russell L.

AU - Barron-Gafford, Greg A

PY - 2013/11

Y1 - 2013/11

N2 - Predicted reductions of cool-season rainfall may expand and accelerate drought-induced plant mortality currently unfolding across the Southwest US. To assess how repeated plant mortality affects ecosystem functional attributes, we quantified net ecosystem CO2 exchange (NEE), ecosystem respiration (R eco), and gross ecosystem photosynthesis (GEP) responses to precipitation (P) at a semidesert grassland over spring (Feb 1-Apr 30) and summer (June 15-Oct 1) plant-active periods across eight years, including two with distinct patterns of extensive species-specific mortality. In addition, we quantified daily soil respiration (R soil) in high- (56-88%) and low-mortality (8-27%) plots the summer following the most recent mortality event. Plant mortality coincided with severely dry cool-season conditions (Dec 1-Apr 30). We found a positive relationship between springtime P and GEP, and that springtime conditions influenced GEP response to summer rainfall. High springtime R eco/GEP ratios followed plant mortality, suggesting increased available carbon after mortality was rapidly decomposed. R soil in low-mortality plots exceeded high-mortality plots over drier summer periods, likely from more root respiration. However, total cumulative R soil did not differ between plots, as variation in surviving plant conditions resulted in high and low C-yielding plots within both plot types. Vegetation status in high C-yielding R soil plots was similar to that across the grassland, suggesting R soil from such areas underlay higher R eco. This, coupled to springtime drought constraints to GEP, resulted in positive NEE under summer P accumulations that previously supported C-sink activity. These findings indicate that predicted lower cool-season precipitation may strongly and negatively affect summer season productivity in these semiarid grasslands.

AB - Predicted reductions of cool-season rainfall may expand and accelerate drought-induced plant mortality currently unfolding across the Southwest US. To assess how repeated plant mortality affects ecosystem functional attributes, we quantified net ecosystem CO2 exchange (NEE), ecosystem respiration (R eco), and gross ecosystem photosynthesis (GEP) responses to precipitation (P) at a semidesert grassland over spring (Feb 1-Apr 30) and summer (June 15-Oct 1) plant-active periods across eight years, including two with distinct patterns of extensive species-specific mortality. In addition, we quantified daily soil respiration (R soil) in high- (56-88%) and low-mortality (8-27%) plots the summer following the most recent mortality event. Plant mortality coincided with severely dry cool-season conditions (Dec 1-Apr 30). We found a positive relationship between springtime P and GEP, and that springtime conditions influenced GEP response to summer rainfall. High springtime R eco/GEP ratios followed plant mortality, suggesting increased available carbon after mortality was rapidly decomposed. R soil in low-mortality plots exceeded high-mortality plots over drier summer periods, likely from more root respiration. However, total cumulative R soil did not differ between plots, as variation in surviving plant conditions resulted in high and low C-yielding plots within both plot types. Vegetation status in high C-yielding R soil plots was similar to that across the grassland, suggesting R soil from such areas underlay higher R eco. This, coupled to springtime drought constraints to GEP, resulted in positive NEE under summer P accumulations that previously supported C-sink activity. These findings indicate that predicted lower cool-season precipitation may strongly and negatively affect summer season productivity in these semiarid grasslands.

KW - climate change

KW - ecosystem respiration

KW - gross ecosystem photosynthesis

KW - net ecosystem carbon dioxide exchange

KW - seasonal precipitation

KW - soil moisture

KW - southern oscillation/El Niño

UR - http://www.scopus.com/inward/record.url?scp=84885228662&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84885228662&partnerID=8YFLogxK

U2 - 10.1007/s10021-013-9675-y

DO - 10.1007/s10021-013-9675-y

M3 - Article

VL - 16

SP - 1178

EP - 1191

JO - Ecosystems

JF - Ecosystems

SN - 1432-9840

IS - 7

ER -