Physical geography

The 3,096 ha reserve is located in the hills along the southern Bahian coast (13º50´S, 39º10´W), 18 km inland from the sea. The reserve forms a narrow 20 km arc, with its widest point reaching 3.5 km and its narrowest not more than 500 m. The property is spread across five ridges aligned on a north/south axis that increase in height from east to west, with peaks between 92-338 m. Hills tend to be steep and flat ground rare.

The reserve is blessed with an abundance of springs and waterways. There are three rivers whose courses run through much of the reserve, the largest being the Cachoeira Grande River (a.k.a. Rio Mariana) that passes along the northern reserve boundary and through the Pancada Grande Forest. While this is one of the largest rivers in the region, it is no more than 10-14 m at its widest and 4 m at its deepest. The river breaks across the coastal hill range as the 61 m Pancada Grande waterfall, one of the most spectacular in the Bahian Atlantic Forest, and joins with the Rio dos Indios briefly before leaving the reserve as the brackish water Serinhaem River. Much of the southern sector of the reserve and the forests of the neighboring Fazenda Itapema I form the headwaters of the Rio Pacangê, which flows through the Pacangê Forest before joining the Cachoeira Grande River to the north. The Rio das Matas is born in a pond between the two southeastern hills of Pacangê and passes through the Luis Inácio and Vila 5 forests, and the agricultural lands to the east before joining the Igrapiúna River. The southeastern hills of reserve form the upper watershed for the Bombaça, Cego, and Barracão rivers all of which flow into the Igrapiúna River. Streams are abundant and the Pacangê Forest has 6, the Luis Inácio Forest 2, the Vila 5 Forest 2, and the Pancada Grande Forest 2 major perennial streams, respectively.

The pleasant climate of the southern Bahian coast has an average precipitation of 2000 mm and daily temperatures between 18˚ and 30˚C, with rainfall throughout the year. There is considerable fluctuation in rainfall between years (range 1313-2666 mm between 1954-2015) and for the same month between years, but in general the heaviest rains fall between February and July, largely coinciding with the austral winter, with the driest period in the summer between August and January. The rains of Santo André, usually falling at the end of November, create a spike in rainfall during the drier part of the year. Patterns of rainfall vary considerably from days when passing clouds bring more than 10 showers to periods when it rains steadily for several weeks. Sometimes in the winter rain clouds hover over this part of southern Bahia for weeks at a time while other regions of the northeast enjoy sunshine. Strong winds, thunder and lightning are rare events, and there are no hurricanes or tornadoes.