Size-dependent species removal impairs ecosystem functioning in a large-scale tropical field experiment

Area of Science:

• Ecology
• Biodiversity Science
• Tropical Ecology

Background:

• Assessing the functional impact of species loss is crucial in biodiversity hotspots facing rapid extinction.
• Incorporating greater realism into ecological models and experiments is needed to understand community responses.

Purpose of the Study:

• To propose and test a conceptual model integrating body size into community responses to environmental change.
• To investigate the role of species diversity and body size in ecosystem functioning within the Western Amazonian rainforest.

Main Methods:

• An exclosure removal experiment was conducted in the Western Amazon.
• Dung and carrion beetle communities (>60 species) were manipulated regarding resource access based on size.
• Experiments were replicated across 10 microhabitats and four climatic conditions.

Main Results:

• Changes in species number, functional groups, and community composition temporal patterns influenced resource burial rates.
• The functional contribution of species diversity within size classes depended on beetle abundance.
• Large species' roles could be substituted by smaller ones under benign conditions, but not under harsher environments.

Conclusions:

• Species may appear functionally redundant under certain conditions, but numerous species are essential for maintaining ecosystem functions across multiple temporal and spatial scales.
• Tropical ecosystems, particularly those experiencing the "Sixth Great Extinction," are potentially fragile, with effects amplified in the Tropics.