An enemy's enemy is an ally: Competitive indirect interactions mediate coexistence of trees, grasses, and subshrubs in Neotropical Savanna

Savannas are complex ecosystems where multiple growth forms, including grasses, trees, and subshrubs, coexist through intricate ecological interactions. Understanding the mechanisms that promote this coexistence is key to conserving savanna biodiversity. This study investigated the effects of grass competition on the survival and growth of trees and subshrubs, as well as the interactions between these two growth forms. Using three species of trees and three species of subshrubs, we conducted a greenhouse experiment to assess how competition between trees and subshrubs is influenced by the presence of grass. We found that grass competition significantly reduced the survival of tree seedlings, while subshrubs were unaffected. When trees and subshrubs competed directly, subshrub biomass was reduced, but only in the absence of grass. Tree seedling biomass was not affected by subshrubs, but was negatively impacted by grass in the absence of subshrubs. Both root and stem biomass of trees and ..., Species selection, experimental design, and establishment
To investigate the effects of a native grass on the growth of subshrubs and trees in Brazilian savanna, we selected three congeneric pairs representing these growth forms. We obtained seeds of the grass Paspalum atratum from the Brazilian Agricultural Research Corporation (Embrapa) and collected seeds for most congeneric pairs in Brasília, Distrito Federal, Brazil, with the exception of Copaifera oblongifolia and Anacardium humile, which were collected in Chapada Gaúcha and Grão Mogol, Minas Gerais, respectively, between November 2013 and July 2014. The factorial experiment involved the presence and absence of grass competition (G+; G-), congeneric competitor and without it (C+; C-) (Figure 1), and two growth forms, trees and subshrubs (T; S). For each species, there were 48 replicates for each combination of grass and congener treatments. We sowed the seeds in polyethylene sacks with a diameter of 20 cm and a depth of 40 cm. The..., , # An enemy's enemy is an ally: Competitive indirect interactions mediate coexistence of trees, grasses, and subshrubs in neotropical Savanna

[https://doi.org/10.5061/dryad.b5mkkwhph](https://doi.org/10.5061/dryad.b5mkkwhph)

**Description of the data and file structure**

**Species selection, experimental design, and establishment**

To investigate the effects of a native grass on the growth of subshrubs and trees in Brazilian savanna, we selected three congeneric pairs representing these growth forms. We obtained seeds of the grass *Paspalum atratum* from the Brazilian Agricultural Research Corporation (Embrapa) and collected seeds for most congeneric pairs in Brasília, Distrito Federal, Brazil, with the exception of *Copaifera oblongifolia* and *Anacardium humile*, which were collected in Chapada Gaúcha and Grão Mogol, Minas Gerais, respectively, between November 2013 and July 2014.

The factorial experiment involved the presence and absence of grass competition (G+; G-), congeneric ...