The transferability of Australian pedotransfer functions for predicting water retention characteristics of French soils.

A French data set was used in evaluating how well two widely used analytical functions describe measured soil water characteristic (SWC) data. Both the van Genuchten (sigmoidal) and Campbell (power-law) equations gave good descriptions of the data (mean R2 of 98.1% and 97.1% respectively). Methods of predicting SWC data were also evaluated. When a power-law equation was parameterised using just two measured SWC points and bulk density (the 'two-point' method), a very good SWC prediction was obtained for the French data (mean R2 of 94.8%). An empirical equation for prediction of the SWC was also assessed using the French data set. This method was developed using multiple regression analysis from Australian soil data and requires soil texture and bulk density as input. The predictions (mean R2 of 85.2%) lacked accuracy and precision in comparison to the two-point method but uses more readily available input data. The accuracy of prediction from both methods was similar to that observed previously for Australian data sets. The empirical approach developed from Australian soil data has reasonable applicability to French soils. The approach of assuming a power-law model and empirically predicting slope and air entry potential is shown to have merit. A strategy for achieving adequate coverage of soil hydraulic property data for France is suggested incorporating hydraulic prediction methods such as those evaluated here

Contrasting Trans-Atlantic Migratory Routes of Nearctic Purple SandpipersCalidris maritimaAssociated with Low Pressure Systems in Spring and Winter

Bird migration is generally scheduled to avoid other energetically expensive events in the annual cycle (e.g. moult) and seasons when survival can be difficult (e.g. northern winters). Purple Sandpipers winter at relatively high latitudes compared to other waders. It is suspected that the majority that winter in Britain and Ireland originate from Canada, but there is no primary evidence of their breeding grounds and migratory routes. These birds, characterised by their long bills, start to arrive in Britain and Ireland in late October/early November, after completing their post-nuptial moult at an unknown location. Fifty geolocators were attached to Purple Sandpipers in northern Scotland and southwest Ireland and we established for the first time their Canadian origin (Baffin Island and Devon Island), migration routes and post-nuptial moulting areas. Spring departure from Scotland and Ireland took place mainly in late May, followed by staging in Iceland and/or southwest Greenland before reaching the breeding grounds. Those that staged in Iceland departed earlier than those that flew directly to Greenland. Post-nuptial moulting areas were in southern Baffin Island, northern Quebec/Labrador (the Hudson Strait), and southwest Greenland. Migration from Baffin Island and Labrador took place during late October – early November, and during mid to late December from Greenland, usually in a single trans-Atlantic flight. Therefore, this migration was scheduled at a time when most other wader species are already on their wintering grounds. No birds staged in Iceland on the return trip. The flight from Baffin Island to Scotland and Ireland was accomplished in about 2.5 days at an average speed of about 1400 km per day. Freezing of coastal waters may be the reason for the eventual departure from the Hudson Strait. The more northerly route via Iceland, taken in spring by most birds, and the more southerly route in early winter were associated with seasonal shifts in the Atlantic low pressure systems (depressions) whose anti-clockwise wind-flows would have assisted flights