The heavy duty, UV resistant cable ties work great (if not UV resistant they crumble after a year or so). We use them for the welded wire fencing and they are perfectly adequate (70+ Lb. lab did the quality assurance testing - tried to get at turkeys...). Three years, so far, and no `erosion'/crumbling.
http://www.uline.com/Browse_Listing_3209.asp?desc=Black+UV+Cable+Ties
http://www.uline.com/Browse_Listing_3209.asp?desc=Black+UV+Cable+Ties