Rainfall and throughfall chemistry in the Atlantic Forest: a comparison between urban and natural areas (São Paulo State, Brazil)

Abstract. Two areas in the Atlantic Forest (Sao Paulo State, Brazil), with contrasting environments in respect of human occupation, were monitored from 1999 to 2001. One area named PEFI (23°38'08''-23°40'18'' S and 46°36'48''-46°38'00'' W) at an altitude of 798 m a.s.l., 526.4 ha in area and about 50 km from the sea, lies in a State Park within the largest metropolis of South America - Sao Paulo. The other area, named CUNHA (between 23°13'18'' and 23°16'10'' S and 45°02'53'' and 45°05'15'' W) about 1050 m a.s.l. with an area of 2854 ha and about 15 km from the sea, is also within a State Park in the Atlantic Forest, but is surrounded by rural areas and small villages. For each area, the rainfall and throughfall chemistry were examined and pH and Na + , K + , Mg 2+ , Ca 2+ , NH 4 + , Cl - , NO 3 - and SO 4 2- as well as trace metals were determined. Compared with PEFI, CUNHA is characterised by low chemical fluxes and the largest differences are for the ions such as Ca 2+ , H + , NO 3- and SO 4 2- which are mainly anthropogenic in origin. Differences in throughfall chemical fluxes are linked to the nutritional status of the trees.