Climate change killed 40 million Australian mangroves in 2015. Here’s why they’ll probably never grow back

In the summer of 2015-2016, some 40 million mangroves shrivelled up and died across the wild Gulf of Carpentaria in northern Australia, after extremely dry weather from a severe El Niño event saw coastal water plunge 40 centimetres. The low water level lasted about six months, and the mangroves died of thirst. Seven years later, they have yet to recover. My new research, shortly to be published in PLOS Climate, is the first to realise the full scale of this catastrophe, and understand why it occurred

Australia's Mangroves: an authoritative guide to Australia’s mangrove plants

Although often under-valued, about 20% of the Australian coastline is occupied by a very special and beneficial habitat of extraordinary trees and shrubs bathed regularly by flooding tides and washing waves. This practical guide describes, for the first time, each of the highly adapted plants that make up this habitat around Australia, and provides you with the means to easily identify them. The book includes: 1) descriptions of all 41 Australian mangroves; 2) illustrated keys for easy identification; 3) more than 1000 photographs and icons covering each species; 4) featured artworks by artist, Fran Davies; 5) sections for each State/Territory with contributions from local specialists; 6) a ‘know-your-coast’ manual for community awareness and education; 7) a water-proof key, called the 'Wheel', for use in the field. This is a book for research, teaching and the eco-minded

A forever young ecosystem: Light gap creation and turnover of subtropical mangrove forests in Moreton Bay, Southeast Queensland, Australia

Light gaps act as important renewal agents in mangrove forests. Light gaps progress through a number of stages starting from the death of a patch of trees through to its infill and rejuvenation of forest. These define a process of mangrove regeneration where forests naturally replace themselves over time. Light gaps in Moreton Bay mangroves were assessed to develop a greater understanding of the physical characteristics and microclimate change with adjacent canopies. Historical aerial photographs from 1978 to 2007 were analysed to reveal the dynamic processes of these mangrove forests and the role of light gap creation. The annual average number of new light gaps and the annual average number of gaps in recovery phases were calculated and used to estimate forest turnover. The average size of gaps in Moreton Bay is 84.2 m2. Average forest turnover based on gap creation decreased from 1987 to 2007. An increase in gap creation rate may be indicative of an increase in storm activity - a possible tangible effect of global climate change

Extreme weather likely behind worst recorded mangrove dieback in northern Australia

[Extract] One of the worst instances of mangrove forest dieback ever recorded globally struck Australia’s Gulf of Carpentaria in the summer of 2015-16. A combination of extreme temperatures, drought and lowered sea levels likely caused this dieback, according to our investigation published in the journal Marine and Freshwater Research. The dieback, which coincided with the Great Barrier Reef’s worst ever bleaching event, affected 1,000km of coastline between the Roper River in the Northern Territory and Karumba in Queensland. About 7,400 hectares, or 6%, of the gulf’s mangrove forest had died. Losses were most severe in the NT, where around 5,500ha of mangroves suffered dieback. Some of the gulf’s many catchments, such as the Robinson and McArthur rivers, lost up to 26% of their mangroves

New partnership network helps to protect Australian mangroves and saltmarsh.

MangroveWatch and the new Australian Mangrove and Saltmarsh Network are helping to link communities and promote information sharing to improve monitoring and management of coastal habitats

Recolonization of mollusc assemblages in mangrove plantations damaged by Typhoon Chan-hom in the Philippines

We investigated the effects of a catastrophic typhoon on mollusc assemblages of damaged mangrove plantations of different ages. Molluscs were sampled from infaunal, epifaunal and arboreal assemblages of mangrove stands in Lingayen Gulf, northwest Philippines, and compared with assemblages of un-impacted areas. Prior to the occurrence of the typhoon, there were clear shifts in the species diversity (H’) and composition of mollusc assemblages with stand age of mangrove forests. This was observed in species composition through the succession in dominance from pioneer to seral or putative climax species, and assemblage type (as arboreal, epifaunal and infaunal). However, severe damage to vegetation structure and sediment properties (associated with a reduction in tree density and canopy cover resulting in increased temperatures and exposure) following the typhoon resulted in an alteration of trajectory patterns in the damaged stands. There were shifts in species composition and dominant species from having mature mangrove-associated species (pre-typhoon) to an abrupt return in dominance of pioneer species (post-typhoon). The damage was more evident in older stands than in intermediate-aged stands. Furthermore, the reduced presence of molluscs (and also probably their activities, i.e. burrowing) may have contributed to the delayed recovery of mangroves. The prospects for recovery of the system to pre-typhoon levels are therefore uncertain where the re-establishment of seral or edaphic mollusc assemblages appears to be related to the recovery of vegetation and sediment conditions

Relationships between estuarine habitats and coastal fisheries in Queensland, Australia

Worldwide, estuaries have been recognized as critical habitats for nearshore fish productivity through their capacity as nursery grounds and nutrient sources. The purpose of this study was to demonstrate the importance of the habitat characteristics of estuaries to commercial fish catch in Queensland, Australia, with particular focus on the role of mangrove, saltmarsh, and seagrass habitats, and their connectivity. Traditionally, such analyses have taken the single-habitat approach, i.e., assessing the value of individual habitat types. Combined occurrence of these habitats and their collective accessibility may better explain the importance of estuaries to nekton. A literature review identifies the role of estuaries as integrated systems for fisheries. Our study provides strong supportive evidence for habitat-based, not species-based, management of fisheries in Queensland. Outcomes from preliminary analyses in Queensland suggest that collective spatial characteristics of estuarine habitats such as size and structural connectivity significantly correlate with fish catch data with r(2) values > 0.7 for 17 commercial species groups. The catch of one quarter of the investigated species was best explained by the presence of mud- and sandflats. An exploration of currently available data on habitat distribution and fisheries catch shows the need to scrutinise their spatial and temporal accuracy, and how best to use them to understand estuarine-fisheries links. We conclude that structural connectivity of estuarine habitats is fundamental to the size of fish stocks and to optimizing the sustainable yield for commercial and recreational fishers

Abandoned, lost and discarded fishing gear ‘ghost nets’ are increasing through time in Northern Australia

The remote Gulf of Carpentaria (GoC) represents 10% of Australia’s coastline. This large, shallow sea supports high value fishing activities and habitat for threatened species, and is a sink for abandoned, lost and discarded fishing gear (ALDFG) ‘ghost nets’, most originating from fishing activities outside of Australia’s Exclusive Economic Zone. With growing concerns about the plastic waste along the world’s coastlines, we retrospectively analyzed ghost net sighting information from four aerial surveys across 15 years, to investigate whether densities of ghost nets are changing through time or in space. We found an increase in ghost nets, despite more than a decade of illegal fishing countermeasure and clean-up efforts in the broader region. This demonstrates that the input of ALDFG into the system currently overwhelms the substantial net removal activities. We make recommendations for improving monitoring and consider the underlying drivers of nets being lost to improve ghost gear management on land and at sea

Systems, interactions and macrotheory

A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI