TY - JOUR
T1 - Risks to carbon dynamics in semi-arid woodlands of eastern Australia under current and future climates
AU - Nolan, Rachael H.
AU - Sinclair, Jennifer
AU - Waters, Cathleen M.
AU - Mitchell, Patrick J.
AU - Eldridge, David J.
AU - Paul, Keryn I.
AU - Roxburgh, Stephen
AU - Butler, Don W.
AU - Ramp, Daniel
N1 - Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Extreme disturbance events, such as wildfire and drought, have large impacts on carbon storage and sequestration of forests and woodlands globally. Here, we present a modelling approach that assesses the relative impact of disturbances on carbon storage and sequestration, and how this will alter under climate change. Our case study is semi-arid Australia where large areas of land are managed to offset over 122 million tonnes of anthropogenic carbon emissions over a 100-year period. These carbon offsets include mature vegetation that has been protected from clearing and regenerating vegetation on degraded agricultural land. We use a Bayesian Network model to combine multiple probabilistic models of the risk posed by fire, drought, grazing and recruitment failure to carbon dynamics. The model is parameterised from a review of relevant literature and additional quantitative analyses presented here. We found that the risk of vegetation becoming a net source of carbon due to a mortality event, or failing to realise maximum sequestration potential, through recruitment failure in regenerating vegetation, was primarily a function of rainfall in this semi-arid environment. However, the relative size of an emissions event varied across vegetation communities depending on plant attributes, specifically resprouting capacity. Modelled climate change effects were variable, depending on the climate change projection used. Under ‘best-case’ or ‘most-likely’ climate scenarios for 2050, similar or increased projections of mean annual precipitation, associated with a build-up of fuel, were expected to drive an increase in fire activity (a 40–160% increase), but a decrease in drought (a 20–35% decrease). Under a ‘worst-case’ climate scenario, fire activity was expected to decline (a 37% decrease), but drought conditions remain similar (a 5% decrease). These projected changes to the frequency of drought and fire increase the risk that vegetation used for carbon offsetting will fail to provide anticipated amounts of carbon abatement over their lifetime.
AB - Extreme disturbance events, such as wildfire and drought, have large impacts on carbon storage and sequestration of forests and woodlands globally. Here, we present a modelling approach that assesses the relative impact of disturbances on carbon storage and sequestration, and how this will alter under climate change. Our case study is semi-arid Australia where large areas of land are managed to offset over 122 million tonnes of anthropogenic carbon emissions over a 100-year period. These carbon offsets include mature vegetation that has been protected from clearing and regenerating vegetation on degraded agricultural land. We use a Bayesian Network model to combine multiple probabilistic models of the risk posed by fire, drought, grazing and recruitment failure to carbon dynamics. The model is parameterised from a review of relevant literature and additional quantitative analyses presented here. We found that the risk of vegetation becoming a net source of carbon due to a mortality event, or failing to realise maximum sequestration potential, through recruitment failure in regenerating vegetation, was primarily a function of rainfall in this semi-arid environment. However, the relative size of an emissions event varied across vegetation communities depending on plant attributes, specifically resprouting capacity. Modelled climate change effects were variable, depending on the climate change projection used. Under ‘best-case’ or ‘most-likely’ climate scenarios for 2050, similar or increased projections of mean annual precipitation, associated with a build-up of fuel, were expected to drive an increase in fire activity (a 40–160% increase), but a decrease in drought (a 20–35% decrease). Under a ‘worst-case’ climate scenario, fire activity was expected to decline (a 37% decrease), but drought conditions remain similar (a 5% decrease). These projected changes to the frequency of drought and fire increase the risk that vegetation used for carbon offsetting will fail to provide anticipated amounts of carbon abatement over their lifetime.
KW - Climate change
KW - Drought
KW - Forest
KW - Grazing
KW - Mortality
KW - Wildfire
UR - http://www.scopus.com/inward/record.url?scp=85060760726&partnerID=8YFLogxK
U2 - 10.1016/j.jenvman.2019.01.076
DO - 10.1016/j.jenvman.2019.01.076
M3 - Article
SN - 0301-4797
VL - 235
SP - 500
EP - 510
JO - Journal of Environmental Management
JF - Journal of Environmental Management
ER -