The Area de Con­ser­va­cion Gua­nacaste (inscribed in 1999), was extend­ed with the addi­tion of a 15,000 ha pri­vate prop­er­ty, St Ele­na. It con­tains impor­tant nat­ur­al habi­tats for the con­ser­va­tion of bio­log­i­cal diver­si­ty, includ­ing the best dry for­est habi­tats from Cen­tral Amer­i­ca to north­ern Mex­i­co and key habi­tats for endan­gered or rare plant and ani­mal species. The site demon­strates sig­nif­i­cant eco­log­i­cal process­es in both its ter­res­tri­al and marine-coastal envi­ron­ments.