Background on Ecosystem

The Paleotropics (“old tropics”) are located in areas near the equator in the Eastern Hemisphere. These include landscapes in Africa, Asia and Oceania (islands north of Australia). The plants, especially the trees, look like “prehistoric” jungles that you might see in Hollywood movies. The sounds of these places come from animals whose calls are loud, diverse and very symbolic of a place that has a long history. The research we have conducted in the Paleotropics was located on the island of Borneo in the eastern portion of the country of Brunei. Here, the trees are very tall (over 300 feet tall) and the tree diversity is the most of any place studied in the world (over 1500 species of trees in a 20 ha site). Common animals that occur here that make sound include: gibbons, hornbills, cicadas, tropical tree frogs, and the barking gecko. Part of our work here is designed to compare to the Neotropics, which are geologically much younger. For comparison, the Paleotropical landscapes in Borneo are over 100 million years old, and those in Costa Rica, our Neotropical study site, are only 2-3 million years old.

Specific Location

Eastern portion of Brunei, island of Borneo January-April 2014

Biome Classification(s)

Köppen-Geiger: Af Equatorial Tropical

Key Partners

Universitii Brunei Darussalam

Threats to Ecosystems and Animals

Logging especially to harvest very straight trunks of old growth trees, palm oil plantations and habitat fragmentation that reduces the amount of core area for large mammal species to live.


Five studies were conducted over the course of nearly 3 months.
  • Study 1: Old Growth Forest Study A set of sensors were positioned along a transect to determine how similar the sounds were along the transect. We use geostatistical (a special class of statistics that analyzes data across space) approaches to analyze the data.
  • Study 2: Old Growth versus Recent Clear Cut. We examined how a recent (~ 10 years ago) clear cut of a forest compared to the soundscapes of the old growth forest.
  • Study 3: Wetland Comparison Study. We placed our acoustic sensors at the edge of three wetlands, each of which had different levels of exposure to river fluctuations, in an attempt to determine if the hydrologic differences created a different animal community.
  • Study 4: Dense versus Open Vegetation Study. As the landscape varies in this area of the world greatly in terms of slope, and slope influenced plant densities (high slope=very dense, small trunk plants; flat = few very large trees and open understory), we set sensors in these two types of habitats to determine how the soundscape might differ between these.
  • Study 5: Is the diversity of biological sounds in the Paleotropics greater than that of the Neotropics? Is there evidence of acoustic niche partitioning that is more complex in the Paleotropics compared to the Neotropics?