The wetland grazer populations in the Caprivi have fluctuated over the past century from being relatively abundant to being near extinction. The fluctuations appear to be linked to long term rainfall cycles. Being on the fringe of larger populations in Botswana, they have usually been able to recover from low levels when the rainfall regime is favourable. Today, the population levels of all four species are a matter for concern: puku are almost extinct; waterbuck have been seen sporadically on surveys but, since 1994, there are no records exceeding 20 animals; lechwe have slumped from nearly 13,000 in 1980 to fewer than 200 now; and reedbuck numbers are about 200 at best.