**3. Materials and methods**

Fieldwork was undertaken from April to Jul 2012 at three sites in the Amazon tropical rainforest of Ecuador (**Figure 1**). The first and second study sites are located in a lowland evergreen secondary forest in Sucumbios province, Tarapoa region (0°11' S, 76°20' W). Site 1 has a history of petroleum pollution during the last decades. Mean annual rainfall is 3800 mm and the average annual temperature is 23°C with relative humidity close to 90% [58]. The area is located at 232–238 m above mean sea level. The third study site is a highly diverse lowland evergreen primary forest located in the Orellana province, in the northern section of Yasuní National Park (0°41' S, 76°24' W). The area lies 216–248 m above mean sea level and receives an annual average of 3081 mm rainfall with peaks in October and November. Mean monthly temperatures vary from 22°C to 34°C [59]. In this site, the Pontifical Catholic University of Ecuador established and manages permanent forest dynamics plots of 50 hectares where over 150,000 mapped trees ≥1 cm in diameter at breast height (dbh) from over 1100 species have been identified [60].

On one hand, the three study sites are located in the lowland Amazon forest sharing very similar ecological and environmental conditions. On the other hand, the forest in the three sites is substantially different due to the land use changes occurred during the last decades. Site 1 and Site 2 are disturbed forest that was exposed to selective logging, agricultural activities, petroleum industry impacts, and secondary forest regrowth over the last 20 years following diminishing human influence. Site 3 is a pristine primary tropical rainforest with legal protection status where a research project on plant and animal species diversity is currently conducted. Studies consider that the plant species richness in this area is among the highest in the world [61].
