Drivers of grassland resistance and recovery to long term drought

Le Brocque, Andrew F and Kath, Jarrod and Reardon-Smith, Kate and Apan, Armando (2017) Drivers of grassland resistance and recovery to long term drought. In: 6th Joint Conference of the Ecological Society of Australia and the New Zealand Ecological Society (EcoTAS 2017) , 26 Nov-1 Dec 2017, Cypress Lakes Resort, Polkolbin, New South Wales.

Abstract

Climate change is expected to increase the intensity of drought in many parts of the world with potentially significant consequences for grasslands. Grassland resilience will depend on its resistance to degradation during drought and ability to recover. We examined the response of grassland biomass to the millennium drought (2002-2010), with rainfall deficits comparable to the hottest and driest climate change scenarios projected for 2030. Following the drought, extreme rainfall occurred in 2010-2011. This juxtaposition between intense and protracted drought and subsequent intense rainfall phase allowed investigation of grassland resistance to drought and recovery in more favourable conditions.

We analysed 2,549 grassland sites in the Darling Downs, Queensland using remotely sensed Enhanced Vegetation Index (EVI) data. We modelled trends in a prolonged drought (resistance) and subsequent wet phase (recovery) as a function of hydro-climatic and land use drivers, using boosted regression trees (BRTs), to determine drivers of grassland resistance and recovery.

Multiple factors explained trends in EVI for both resistance (CVpred/obs. = 0.69) and recovery (CVpred/obs. = 0.61). During drought, resistance decreased as the proportion of agriculture increased and woody vegetation decreased. In contrast, there was little relationship with agriculture during recovery and increased woody vegetation had a negative relationship with recovery. High levels of soil moisture corresponded to both increased resistance and recovery. The drivers we examined had differential effects for grassland resistance and recovery, which may have implications for the ongoing resilience of these systems under future climate change.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Speech)
Refereed: No
Item Status: Live Archive
Additional Information: Only abstract as provided here was published in the downloadable conference programme.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 06 Jun 2018 04:30
Last Modified: 21 Jun 2018 04:04
Fields of Research : 06 Biological Sciences > 0602 Ecology > 060208 Terrestrial Ecology
05 Environmental Sciences > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960904 Farmland, Arable Cropland and Permanent Cropland Land Management
D Environment > 96 Environment > 9605 Ecosystem Assessment and Management > 960504 Ecosystem Assessment and Management of Farmland, Arable Cropland and Permanent Cropland Environments
URI: http://eprints.usq.edu.au/id/eprint/33430

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