Understanding hydrological processes in water-limited systems requires consideration of temporal and spatial vegetation water use patterns at the landscape scale. We used data derived from the MODerate Resolution Imaging Spectroradiometer (MODIS) satellite instrument and interpolated climate data covering a ten-year period to contrast the spatio-temporal patterns of actual evapotranspiration (AET) from known phreatophytic and non-phreatophytic vegetation overlying a large superficial aquifer. We assessed shallow to deeper groundwater habitats and compared AET responses to seasonal and inter-annual variation in precipitation. Overall, vegetation in shallow groundwater habitats had higher AET rates during the growth season (spring and summer) than vegetation growing in deeper groundwater habitats, suggesting that the former was not physiologically constrained by water deficit. Vegetation in areas of consistently high (ground-)water availability maintained higher AET, reaching a peak of 95 mm in mid-summer. In contrast, plantation maritime pines had the highest AET rates at deep groundwater habitats. Inter-annual variability in AET correlated with rainfall and AET rates peaked two months after the majority of effective rainfall had fallen. During low rainfall years, maximum AET peaked one month earlier relative to higher rainfall years. The results of this study suggest that remote sensing of AET can give a conditional indication of where groundwater is important in supporting vegetation and can be a valuable tool in identifying management focus areas where vegetation is variably sensitive to water deficit. Copyright © 2016 John Wiley \u26 Sons, Ltd. Copyright © 2016 John Wiley \u26 Sons, Ltd

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A survey of 11 sites covering three large (>10 km long, 6 sites) playa lakes and four pans ( < 1 km 2 , 5 sites) of the Yarra Yarra salt lake system in the Northern Agricultural Region of Western Australia commenced in 2001. These salt lakes are shallow and ephemeral, with inundation being more regular following winter rainfall, but summer inundation also occurred in 2001. Salinity was generally higher in playas (156-368 g l -1 ) than pans (30-284 g l -1 ), but salinity responded noticeably to heavy rainfall events, especially in pans. pH values in the playa lakes (6.68-7.82) were less variable than in the pans (6.81-8.08). The range of dissolved oxygen concentrations was greater in pans (3.7-14.4 mg l -1 ) than in playas (3.9-8.2 mg l -1 ). Cationic concentrations generally followed the pattern of sea water cation dominance. Benthic microbial communities comprised either cohesive to loosely mucilaginous mats, or thin films of diatoms. Five genera of diatom and two species of filamentous cyanobacteria were recorded.

Diatom diversity of six small playa lakes within the Yarra Yarra drainage system, Western Australia, and the environmental variables likely to influence their distribution was investigated. Thirty-one pennate diatom taxa were identified. Taxa consisted of facultative planktonic and periphytic, circumneutral to alkaliphilous or pH-indifferent forms with known adaptations to saline conditions and fluctuations in salinity in NaCl dominated waters. Data were analysed by ordination (MDS and PCA), hierarchical clustering (CLUSTER), permutation-based hypothesis testing (ANOSIM) and comparative tests on similarity matrices (RELATE). Water depth accounted for the majority of variation in the environmental data. REALTE comparisons of environmental and taxa data did not produce a significant correlation value. We propose that the poor concurrence of the datasets was influenced by the wide ecological tolerances of the taxa recorded, some crucial unmeasured environmental variable/s, possible geographical regionalisation and/or unsampled taxa variability owing to the stochastic nature of the wetlands. Broad patterns of distribution were related to hydroperiod and some taxa groups were loosely associated with environmental groups consistent with established ecological tolerances for the taxa.