Wetland hydrology in an agricultural landscape: implications for biodiversity.

1. Wetland hydrology in an agricultural landscape: implications for biodiversity. Jarrod Kath 1 Andrew Le Brocque1 Craig Miller2 1 Australian Centre for Sustainable Catchments / Faculty of Sciences, University of Southern Queensland, Queensland, Australia 2 Climate Adaptation Flagship and CSIRO Sustainable Ecosystems, Brisbane, Queensland, Australia

2. Introduction - Landscape perspective • Australia’s floodplain landscapes are highly variable, both spatially and temporally. • Consist of a range of wetland habitats representing different hydrological conditions throughout landscape • Maintaining a range of wetland types is important for biodiversity throughout a landscape (Roshier et al., 2002; Amona et al., 2008).

3. Introduction – Research Question • How wetland hydrology changes across a landscape under changing climatic conditions, specifically drought conditions, is unknown. • Predicted by 2030 - 9% reduction in annual runoff (CSIRO, 2008). • This study investigates changes in the hydrology of wetlands in an agricultural landscape between 1987-2005 and 2000-2005 (dryer climatic period) to examine how wetlands may change through time under changing climatic conditions.

4. CHINCHILLA DALBY TOOWOOMBA WARWICK CHINCHILLA SCENE n =105 DALBY SCENE n = 75 WARWICK SCENE n = 71 Study area Figure 1 The Condamine catchment, showing the location of the 251 wetlands across the three regions - Chinchilla, Dalby and Warwick.

5. Wetlands in Condamine Catchment >2000 wetlands (QEPA, 2008) significant vegetation loss (Fensham & Fairfax, 1997) and hydrological changes (Thoms & Parsons, 2003). altered wetland hydrology (Thrupp & Moffat, 2001) ring tanks (10%) levees (27%) channels (20%) water pumps (14%)

6. Methodology • wetland hydrology variables derived from an annual snapshot of wetland from satellite data (1987-2005) • based on these metrics for • - inundation frequency • - variability (how often switch from wet to dry) • - duration of longest wet and dry periods • wetlands categorised (to examine changes ín frequency of wetland types) • also, anlaysed as continous data (to examine overall changes to collective wetland hydrology) 6

7. Wetland hydrological classification Table 1 Response variables for wetland hydrology used for analysis. Metrics derived from QWBD (2005) metadata for wetlands in the Condamine catchment. *only calculated for the Chinchilla sub-region

8. Inundation frequency * ** Figure 3Number of wetlands in each ordinal category for TI1987-2005 and TI2000-2005 for the entire region and for each sub-region. Inundation frequency: (■) rarely inundated; (■) intermittently inundated; (■) frequently inundated.

9. Inundation frequency * Figure 3Number of wetlands in each ordinal category for TI1987-2005 and TI2000-2005 for the entire region and for each sub-region. Inundation frequency: (■) rarely inundated; (■) intermittently inundated; (■) frequently inundated. 9

10. Confidence intervals Figure 5 Chinchilla region confidence intervals comparing (a) Longest dry, (b) Longest wet and (c) Variability across three different time periods. (c) 10

11. Confidence intervals Figure 5 Chinchilla region confidence intervals comparing (a) Longest dry, (b) Longest wet and (c) Variability across three different time periods. (a) 11

12. Confidence intervals Figure 5 Chinchilla region confidence intervals comparing (a) Longest dry, (b) Longest wet and (c) Variability across three different time periods. (b) 12

13. Hydrological changes: finding #1 • Overall increase in rarely inundated wetlands & reduction in intermittent wetlands • however, only significant in the Chinchilla sub-region • differences between sub-regions may be consequence of different (localised) land use practices. • Dalby and Warwick sub-regions were historically and are currently far more heavily utilized for agriculture. • more irrigated agriculture and less native vegetation (QEPA, 2003)

14. Hydrological changes: finding #2 • in Chinchilla sub-region, wetlands dryer or wetter for longer and overall wetlands less variable • – represents a significant change in hydrological regime • Brock et al., (1999) argue that many wetlands remaining in agricultural landscapes have water regimes altered in such a way that their ‘stability’ is increased, so that they are more continuously either dry or wet. • implications for biodiversity and ecosystem resilience?

15. Conclusions • could have substantial implications for overall landscape biodiversity • climate change and anthropogenic activities may intensify these changes in the future • future research should examine how hydrological diversity changes in a landscape and link this to biodiversity and other socio-ecological values

16. Acknowledgements Acknowledgements: Megan Batterham, Kate Reardon-Smith, Dr Jerry Maroulis, ACSC, QMDC, CA, QEPA, & landholders of the Condamine Supported by: APA Postgraduate Research Scholarship CSIRO Top up Scholarship (Climate Adaptation Flagship)