Linking the brown and green world: The effects of large herbivores on soil properties in a tropical forest

• Grant number: 23/12828-5
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: December 01, 2023
• End date: February 28, 2027
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Mauro Galetti Rodrigues
• Grantee: Letícia Gonçalves Ribeiro
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Associated research grant: 21/10639-5 - Center for Research on Biodiversity Dynamics and Climate Change, AP.CEPID
• Associated scholarship(s): 25/03637-7 - The effect of large mammal herbivores on soil nematodes in tropical forests, BE.EP.DR

Abstract

Understanding the interactions between aboveground and belowground components is vital for comprehending the functioning of terrestrial ecosystems. Theory predicts that soil fertility (belowground component) is a key factor in regulated plant biomass (aboveground component) which, in turn, controls the biomass of consumers and prey. Large mammalian herbivores (LMHs) play an important function in the top-down regulation of plant biomass through herbivory and trampling and alter the chemical composition and nutrient allocation of plants. These changes are directly reflected in the litter deposited on the soil surface which is considered the main input of soil nutrient cycling. Current hypotheses have suggested that forest-dwelling LMHs act by decelerating nutrient cycling, while in grassland ecosystems they act by accelerating nutrient cycling. However, these responses can be context-dependent, thus constraining our predictions for making broad generalizations. Tropical forests face high levels of defaunation of LMHs mainly due to habitat loss and hunting, and this scenario can be worsened in the future due to climate change. These problems ascend a red light with species loss happening even before we understand their function in these tropical forest ecosystems, including their interactions between the aboveground and belowground. Such interactions play a major role in the regulation of biodiversity and key ecosystem processes such as carbon storage and nutrient cycling. Surprisingly, these interactions have not been deeply studied in the highly diverse and threatened tropical forests. In this proposal, we will combine a theoretical (Chapter 1) and a field-based experiment (Chapters 2-4) to understand the effects of biodiversity loss of LMHs on soil properties in tropical forests.