Bolivia Guide
The Amazon
Reserva de la Biosfera del Beni
Covering some 1350 square kilometres of savanna and rainforest to the east of San Borja, the Reserva de la Biosfera del Beni (Beni Biosphere Reserve) was one of the first protected areas to be established in Bolivia. Standing at the intersection of two important biogeographical zones, the reserve is exceptionally bio-diverse, hosting some 500 species of birds and 100 species of mammals – these include almost half the protected species in Bolivia, among them many that are in danger of extinction. Illegal hunting, unfortunately, still poses a major threat.
Unusually for Bolivia, the reserve also has very well-organized facilities for visitors, based at the Beni Biological Station at El Porvenir, a former ranch about 100km west of San Ignacio on the road to San Borja. Though most of the reserve is actually rainforest, the area immediately around El Porvenir is largely savanna, a seemingly endless sea of natural grasses up to 2m high, dotted with islands of forest. The reserve is open all year round, but during the rainy season the whole area becomes flooded and the road is impassable, so you can really only visit between May and October.
If you're travelling in a big group it's probably worth phoning the reserve office in San Borja, which is on Trinidad with 18 de Noviembre ( 
03/8953895 or 03/8953898) a day in advance to let them know you're coming, but otherwise it's fine to arrive at El Porvenir unannounced. To reach the biological station take any bus or truck heading east from San Borja or west from San Ignacio and ask the driver to let you off at El Porvenir, about 50km from San Borja. Admission is $5 per person and accommodation in basic but clean barrack-like rooms with shared bathrooms costs $12 per person, including three meals a day, or $9 a day if you bring your own equipment and camp. They also have an extensive scientific library which visitors can use and a small exhibition of T'simane crafts; in addition, local T'simane sometimes bring bows and woven baskets to sell to visitors. Moving on can be tricky: your only option is to try to flag down one of the few passing vehicles.