The project, Regeneration of floodplain vegetation in response to large-scale flooding in the Condamine-Balonne and Border Rivers, was a collaboration between the Cotton CRC, QLD DERM, NSW Office of Water and the Australian Rivers Institute of Griffith University. The aims of the project were to i) describe spatial and temporal patterns in the regeneration of major riparian tree and shrub species in the Condamine-Balonne and Border Rivers following the major floods of early 2011 and ii) identify key factors, particularly hydrological, influencing these patterns.The project comprised two major components: i) a literature review and associated development of conceptual models for key riparian tree and shrub species of Australian arid and semi-arid catchments and ii) a field study program. The field study program involved surveying up to twenty-five 50m long transects across nine sites along the Weir, MacIntyre and Balonne rivers on three occasions: September and November 2011 and March 2012. Prior to the first survey all sites received significant overbank flows preceded by an extended period of drought (c. 10 yrs). Further flooding also occurred during the study period prohibiting repeated surveys at several sites. During each survey, all woody seedlings (< 1 m) present in transects were recorded and measured. Relevant environmental characteristics were also measured (e.g. soil characteristics, canopy cover, elevation etc.) and the composition of the canopy and presence of seeds recorded. Additionally, a further 70 seedlings across four sites, including Eucalyptus coolabah (coolibah), Acacia stenophylla (river cooba) and Atalaya hemiglauca (whitewood) were tagged and measured to monitor survival and growth during the study period.Seedling establishment was found to be sparse and spatially patchy. Over half of seedlings recorded during each trip were Acacia stenophylla seedlings and these were present at all sites. Muehlenbeckia florulenta (lignum) seedlings were also relatively common and widely distributed. Eucalyptus coolabah seedlings were comparatively rare but were present at six of the nine sites. Atalaya hemiglauca (whitewood) seedlings were also encountered relatively frequently. Only two Eucalyptus camaldulensis (river red gum) seedlings were observed in the entire field study. The range of seedling sizes present at each time suggest that the Acacia stenophylla seedlings observed represented single germination events on each occasion with the tagged seedling study also suggesting limited survival of small seedlings between September and March. Eucalyptus coolabah seedling sizes were also indicative of a single, but considerably earlier, establishment event. In contrast, Muehlenbeckia florulenta appears to be recruiting continuously in these habitats. Larger tagged Acacia stenophylla seedlings exhibited rapid growth over the survey period while Atalaya hemiglauca displayed slower growth and Eucalyptus coolabah seedlings showed a mixed growth response.Significant variation in the composition and density of seedling assemblages was detected between the major river catchments, driven by the abundance of Acacia stenophylla seedlings, with strong variation at the site-scale also apparent. For the September 2011 observations, total seedling density was negatively related to the time since inundation and the duration of the last flood event positively related to Acacia stenophylla seedling density and negatively related to Eucalyptus coolabah density.The results of this project indicate that large floods do not necessarily trigger major recruitment events amongst key riparian tree and shrub species in this region. Recruitment of key species (e.g. Eucalyptus camaldulensis and E. coolabah) does not appear to be limited by seed availability as seeds were observed in the canopy and on the soil surface at all sites.Consequently, germination and seedling establishment in these species are likely to require floods with particular attributes (e.g. duration, timing etc.) possibly in combination with a suite of other conditions (e.g. rainfall, temperature). Understanding vegetation regeneration in these significant habitats to better inform water resources management will depend on the establishment of a well-designed long-tem monitoring program that captures recruitment patterns over a large and diverse array of sites.