The parts of the Western Front where German defences were rebuilt on the new principles, or had naturally occurring features similar to the new principles, such as the Chemin des Dames, withstood the Franco-British attacks of the Nivelle Offensive in April 1917, although the cost in casualties was high. The "rate" of German infantry losses in these defences diminished, although this was also apparent in the "rate" of loss of the attackers, who were better organised and used more efficient methods, made possible by the increased flow of equipment and supplies to the Western Front, which had so concerned Ludendorff in September 1916 (In 1917 British artillery ammunition shortages ended and barrel-wear, from firing so many shells became a problem.) At Verdun in December 1916, Arras in April 1917 and at Messines in June, where the new German defensive principles of depth, camouflage and reverse-slope defences, dispersed methods of fortification and prompt reinforcement by divisions, were not possible or had not been adopted in time, the British and French armies inflicted costly defeats on the Germans.