Ecological Contingency Accounts for Earliest Seagoing in the Western Pacific Ocean

Seagoing at 1 mya to Flores, and sea gaps of >50 km crossed by 47 kya to Sahul, are evidence of earlier maritime migration in the western Pacific than anywhere else. Current opinion attributes the latter to the influence of anatomically modern human cultural complexity on seagoing technology and practice, together with the impetus of serial resource depression. It is argued here that seagoing was unusually advantaged in the western Pacific by a fortuitous conjunction of the warmest seas with a ready availability of large-diameter bamboo that occurred as natural rafts, and which could also be constructed into rafts large enough to transport viable colonizing groups from island to island across Wallacea to Sahul. The geography of Wallacea allowed migration solely by drifting, and exploratory landscape learning might have produced landfalls on Sahul sooner than is implied by subsistence forcing of mobility. Seagoing by drifting raft was much harder from Sahul to the east because of the virtual absence of large-diameter bamboo and longer distance to fewer or small islands; colonization occurred much later.     

Robert Newall's Primary Record of the Prehistoric Ship Graffiti at Hal Tarxien,Malta: new thoughts on their significance

Recent research on now indistinct ship graffiti in the Third Temple at Hal Tarxien led to discovery of a full‐size record made 50 years ago. Correspondence elucidates contemporary interpretation of the context. Colonization of the island from Sicily c.5000 BC probably involved large flotation devices similar to those identified on the lowest tier of graffiti. A Neolithic date for some of the images finds support with the identification of a raft supporting the cult statue located in the same part of the temple.     

Water,Wind, Wood,and Trees: Interactions,Spatial Variations,Temporal Dynamics,and their Potential Role in River Rehabilitation

Recent Australian research has quantified the role of large wood (wood of any origin and length with a diameter greater than 0.1 m) in dissipating stream energy, forming pool habitats by local bed scour, protecting river banks from erosion, and damming rivers with long rafts causing avulsions. Large wood in Australian streams is sourced by a range of processes from the nearby riparian zone which has usually been degraded by post‐European settlement vegetation clearing. Large wood loadings within the bankfull channel are dependent not only on the type and quality of the riparian plant community but also on bankfull specific stream power, channel width, and the processes of large wood delivery to the stream. While bank erosion and floodplain stripping by catastrophic floods are obvious and important delivery mechanisms, treefall and trunk and branch breakage by strong winds during tropical cyclones and severe storms are also significant in the tropics. Furthermore, wood decay and downstream transport produce temporally dynamic large wood distributions. The longevity of natural large wood structures in rivers, such as rafts, debris dams, and log steps, requires determination. River rehabilitation programs need to not only include the reintroduction of large wood, but also carefully plan the spatial distribution of that wood, the most appropriate type and range of large wood structures, and, most importantly, the revegetation of the riparian zone to ensure a natural long‐term source of large wood. Exotic species management is an essential part of river rehabilitation.