Energy pathways modulate the resilience of stream invertebrate communities to drought

Area of Science:

• Ecology
• Environmental Science
• Climate Change Research

Background:

• Climate change impacts ecosystems globally, but responses vary.
• Food web theory posits that diverse energy pathways (green, brown, multi-channel) enhance community stability and resilience.
• Empirical data on how different food web structures affect resilience to climate change stressors are limited.

Purpose of the Study:

• To investigate the effects of warming and drought on stream invertebrate communities.
• To determine if food web structure (green, brown, multi-channel) influences community resilience to climate change.
• To assess the independent and interactive effects of warming and drought on different food web types.

Main Methods:

• Factorial experiment using outdoor stream mesocosms.
• Manipulation of warming and drought conditions.
• Comparison of invertebrate community responses across green, brown, and multi-channel food web configurations.

Main Results:

• Warming had minimal impact on invertebrate communities.
• Stream drying significantly reduced invertebrate abundance, biomass, richness, and diversity.
• Green food webs exhibited higher resilience and recovery from drying compared to brown and multi-channel food webs.
• Resilience varied among taxa, with larger predators showing lower resilience.

Conclusions:

• Food web structure, specifically the reliance on producer-based (green) energy channels, enhances stream community resilience to drought.
• Drought impacts are influenced by the basal resources (autochthonous vs. allochthonous) fueling the food web.
• Complex substrates and organic matter may provide refugia, increasing resilience in certain stream types.