Ecosystem Shift from Submerged to Floating Plants Simplifying the Food Web in a Tropical Shallow Lake

Author(s)

Moi, Dieison Andre ^[1] ; Alves, Diego Correa ^[1] ; Antiqueira, Pablo Augusto Poleto ^[2] ; Thomaz, Sidinei Magela ^[1] ; Teixeira de Mello, Franco ^[3] ; Bonecker, Claudia Costa ^[1] ; Rodrigues, Luzia Cleide ^[1] ; Garcia-Rios, Raul ^[1] ; Mormul, Roger Paulo ^[1]

Affiliation

^[1] Univ Estadual Maringa, Programa Posgrad Ecol Ambientes Aquat Continentai, Ave Colombo 5790, Bloco H90, BR-87020900 Maringa, Parana - Brazil

^[2] Univ Estadual Campinas UNICAMP, Inst Biol IB, Programa Posgrad Ecol, Campinas - Brazil

^[3] Univ Republ, Dept Ecol & Gest Ambiental CURE, Tacuarembo S-N, Maldonado - Uruguay

• Document type: Journal article
• Source: ECOSYSTEMS; v. 24, n. 3, p. 628-639, APR 2021.
• Web of Science Citations: 6

Abstract

Shifts between the alternative stable states have been a popular topic of ecological studies for over 50 years. However, identifying the mechanisms that drive these regime shifts remains a challenging task in the field of applied ecology and ecosystem management. Herein, we applied a Bayesian latent variable regression (BLR) to the dataset obtained for a shallow lake experiencing a shift from the dominance of submerged plants to the dominance of floating plants to classify the observed lake states, determine total phosphorus (TP) thresholds, and establish a steady-state relationship between the phosphorus content and the size of an aphotic zone. In addition, a structural equation model was utilized to elucidate the mechanisms driving this shift and their effects on the trophic web of the ecosystem. The BLR model exhibited high state classification rates (median/mean accuracy > 97.5%) and accurately determined the steady-state relationships between the TP thresholds and the aphotic zone size. We also found that the top-down control via piscivorous fish was stronger in the state dominated by submerged macrophytes, while the bottom-up control via TP was stronger in the state dominated by floating macrophytes. Additionally, the dominance of floating macrophytes was related to the low degree of biodiversity and simplification of the trophic web. Our results show that top predators can be used to control nutrient levels and ensure the dominance of submerged macrophytes. It also provides a new perspective on the theory of alternative states and potential tools for the management of ecosystems experiencing regime shifts. (AU)

• FAPESP's process: 17/26243-8 - Extreme rainfall events and their effects on the community structure and ecosystem functioning
• Grantee: Pablo Augusto Poleto Antiqueira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral