Incorporating dugong habitats into the marine protected area design for the Great Barrier Reef Marine Park, Queensland, Australia.

Dugong habitats were considered in the design for the new zoning network for the Great Barrier Reef Marine Park as part of the Representative Areas Program. One of the specific design guidelines developed as part of the biophysical operational principles recommended that 50% of all high priority dugong habitats should be incorporated in the network of no-take areas. The high priority dugong habitat incorporated in no-take protection increased from 1396 to 3476 km2 (or 16.9-42.0% of all identified sites). Although this increase in protection fell short of the recommended 50%, overall the level of protection afforded by the Great Barrier Reef Marine Park Zoning Plan 2003 increased for all the locations identified.

Recruitment dynamics of invasive species in rainforest habitats following Cyclone Larry

In tropical forests, natural disturbance creates opportunities for species to claim previously utilized space and resources and is considered an important mechanism in the maintenance of species diversity. However, ecologists have long recognized that disturbance also promotes exotic plant invasions. Cyclones cause extensive defoliation, loss of major branches and multiple tree falls, resulting in a significantly more open canopy and increased light and heat levels in the understorey. The widespread and massive disturbance caused by cyclones provides ideal conditions for rapid recruitment and spread of invasive species. The ecological roles of invasive species in rainforest habitats following such a severe disturbance are poorly understood. Severe category 4 Cyclone Larry crossed the North Queensland coast in March 2006 causing massive disturbance to rainforest habitats from Tully to Cairns and west to the Atherton Tablelands. We established 10 plots in an area extensively damaged by this cyclone near El Arish in North Queensland. On each plot nine 2 × 2 m quadrats were established with three quadrats per plot in each of the following treatments: (i) complete debris removal down to the soil layer, (ii) removal of coarse woody debris only, and (iii) uncleared. We monitored recruitment, growth and mortality of all native and invasive species in the 90 quadrats every 3 months since the cyclone. Here we present the recruitment dynamics of invasive species across the study area in relation to the level of disturbance, the type of quadrat treatment, and the diversity and abundance of the native recruiting flora over the first 12 months post-cyclone. Our results suggest that invasive species will mostly comprise a transient component of the flora in the early stages of the successional response. However, some species may have longer-term effects on the successional trajectory of the rainforest and future forest composition and structure.

Dispersal and establishment of bird-dispersed weed and native species in early successional subtropical habitats

Eve White, Anna Barnes and Gabrielle Vivian-Smith recently published their paper 'Dispersal and establishment of bird-dispersed weed and native species in early successional subtropical habitats' in Proceedings of the 16th Australian Weeds Conference. Eve also presented this paper at the conference. They investigated patterns of dispersal and establishment of bird-dispersed weeds and native species in early successional habitats in northern New South Wales. Patterns varied among growth forms, between native species and weeds, and among vegetation types. Their results indicated that the number of seeds dropped by birds is not necessarily a good predictor of recruitment and that post-dispersal factors, such as microsite characteristics, may be more important influences on seedling recruitment. This knowledge will assist with designing management strategies for bird-dispersed weeds in natural areas.

Efficacy of exclusion fencing to protect ephemeral floodplain lagoon habitats from feral pigs (Sus scrofa)

Foraging by feral pigs can strongly affect wetland vegetation assemblages and so too wider ecological processes, although their effects on freshwater ecosystems have seldom been tudied. We assessed the ecological effects of pig foraging in replicate fenced and unfenced ephemeral floodplain lagoons in tropical north-eastern Australia. Pig foraging activities in unfenced lagoons caused major changes to aquatic macrophyte communities and as a consequence, to the proportional amounts of open water and bare ground. The destruction of macrophyte communities and upheaval of wetland sediments significantly affected wetland turbidity, and caused prolonged anoxia and pH imbalances in the unfenced treatments. Whilst fencing of floodplain lagoons will protect against feral pig foraging activities, our repeated measures of many biological, physical and chemical parameters inferred that natural seasonal (i.e. temporal) effects had a greater influence on these variables than did pigs. To validate this observation requires measuring how these effects are influenced by the seemingly greater annual disturbance regime of variable flooding and drying in this tropical climate.