Shade drives plant community changes of ground‐layer savanna vegetation: Short‐term changes under an experimental approach

Abstract

Aim Woody‐plant encroachment is a reality in many savannas worldwide, leading savannas to become replaced by forest ecosystems. As tree density and cover increase, increased shade and litter deposition may suppress the savanna's community of low‐lying plants. By using field manipulation, we tested shading and litter effects, alone and in combination, on the savanna's ground‐layer plant community. We investigated how changes in these environmental factors may affect the composition, structure, and above‐ground biomass in the plant community of a species‐rich Neotropical savanna. Location Savanna patches in the Cerrado, southeastern Brazil. Methods Annual surveys of the herbaceous–shrub layer in a three‐year field manipulation experiment examining shading and litter deposition. Results Shade negatively affected all evaluated parameters, while litter addition had only minor effects. The largest losses of richness, density, and cover occurred in forbs and grasses. Increased shade resulted in a sharp decrease in the above‐ground biomass of monocots. Conclusions Our results show that light is a strong environmental filter for the ground‐layer community. The reductions in grass cover and biomass under shade treatments likely altered ecosystem functioning. Woody encroachment can thus be considered to represent a process that can alter the structure and functioning of savannas. Management interventions should therefore be taken to prevent woody encroachment or mitigate its harmful effects on savanna biodiversity and ecosystem functioning.

Multifunctional redundancy: Impossible or undetected?

“…soil microbial systems) and the weak and the strong biotic and abiotic interactions that are key for redundancy relationships. The outcomes of these studies will undoubtedly contain unexplained variation due to unknown mechanisms, but will allow us to focus on mechanisms underlying these responses, and better understand natural systems (Box 3 ; Pinheiro et al, 2022 ).…”

“…undoubtedly contain unexplained variation due to unknown mechanisms, but will allow us to focus on mechanisms underlying these responses, and better understand natural systems(Box 3;Pinheiro et al, 2022).Multifunctionality research up to this point has allowed us to expand our understanding of the complexity of biodiversity-ecosystem functioning relationships. However, to untangle it, further we must tread carefully through the web of existing methodology to design appropriate studies.…”