The New Neotropical Companion

Neotropical River Ecosystems:

Orinoco and Amazon

One of the most enjoyable ways to explore Amazonia is
to take a river cruise. Excellent well- apportioned boats
specifically designed for ecotourism on the Amazon
River launch from Iquitos, Peru, and Manaus, Brazil.
Wonderful travel is also available along the Río Napo
in Ecuador and in numerous other wetlands, including
the Pantanal floodplain of Brazil and the seasonally
inundated Llanos (Plains) of Venezuela. Similar trips
can be booked in Central America, particularly Belize,
Costa Rica, and Panama. As you ride along the various
Neotropical rivers you will see not only the sights
and hear the sounds from the forest along the river
itself, but you will also likely have the opportunity for
exploration of backwaters and inlets, where even more
wildlife is found (plates 12- 1– 2).
Because of wet- dry seasonality, tropical rivers
experience an annual flood cycle that exerts a significant
impact on bordering ecosystems, especially gallery

(riverine) forests. In addition, rivers are bordered by

numerous ecosystems, including swamps, marshes,

streams, oxbows, and river islands. Each of these habitats

contains species that otherwise would not be seen along

the main rivers, adding significantly to regional diversity

and the satisfaction of river travel (plate 12- 3).

The Orinoco River

The Orinoco River is 2,140 km (1,330 mi) long,

flowing northeast from the Río Guaviare in eastern

Colombia and bisecting Venezuela before exiting to

the Atlantic Ocean (fig. 12- 1). Considering average

annual discharge, it ranks as the third- largest river

in the world. The Orinoco Basin, though large, is but

one- sixth the area of the Amazon Basin, to which it

connects via the Río Casiquiare, which flows into the

Río Negro, which itself is part of the Amazon Basin.

Much of the Orinoco Basin drains the geologically

ancient Guiana Shield, located southeast of the main

river (discussed below).

COLOMBIA

Ciudad Bolivar

Ciudad Piar

Ciudad

Guayana^8 °

6 °

4 °

2 °

86 ° 84 ° 82 °

VENEZUELA

EI Tigre

EI Callao

Tumeremo

Tucupita

BRAZIL

Puerto

Infrida

Missao Macajai

Puerto

Carreño GUIANA

H IGHLANDS

Arauca

LLANOS

Valle

de la

Pascua

Rio Apure

San Fernando

de Apure

Pariaguan

Rio Orinoco

Roraima 2,875 m (9,432 ft)

RORAIMA

Benjamim

AMAZONAS

S

E

L^

V

A

S

Rio

(^) N
eg
ro
Rio (^) O
rino
co
Figure 12– 1. Map of the Orinoco River. Reprinted with permission from Kricher, John. Tropical Ecology. Princeton, NJ: Princeton
University Press, 2011.

Chapter 12. Cruising the Rivers to the Sea

205