The impact of native- and exotic-planted forest plantations on ant biodiversity in the Amazon region

Global warming is one of the most pressing and challenging problems that we face in this century. Although planted forests increase carbon uptake they may also have negative impacts on biodiversity. To examine this possibility, and see how native- and exotic-planted forest plantations differed, we compared ant biodiversity in teak (Tectona grandis), exotic, and paricá (Schizolobium amazonicum), native, forest plantations in Pará, Brazil. We collected ants in pitfall traps in three plantations for each forest type, and at each site measured a number of environmental variables to see which affected ant species diversity. We used smoothed species accumulation curves to compare ant biodiversity between native- and exotic-planted forests and an analysis of variance with GLM to measure the impact of forest plantations and environmental variables on ant biodiversity. We collected 64 ant species, with 60 species from paricá and 35 from teak. The estimated ant biodiversity was significantly different between the two forests. High leaf litter biomass, shorter distance from native forest to teak plantation associated with high plant species richness, and high amounts of soil calcium supported higher ant biodiversity. The relationship between high leaf little biomass and ant biodiversity was seen just in paricá plantations.

Although teak plantations sequester carbon they support lower levels of biodiversity compared to paricá forests. In the Amazon, a global biodiversity hotspot, it is important that strategies to mitigate climate change don’t reduce biodiversity. This study helps us understand the potential tradeoffs between carbon sequestration and biodiversity loss in the Amazon.