Differing Impacts of Livestock Farming and Ranching on Aquatic Insect Biodiversity: A Global Meta-Analysis.

Area of Science:

• Ecology
• Environmental Science
• Biodiversity Research

Background:

• Global insect biodiversity trends show declines in terrestrial and some aquatic species.
• Livestock farming, a major land user, poses a growing threat to biodiversity.
• Impacts of livestock on aquatic insect biodiversity are not globally synthesized.

Purpose of the Study:

• To investigate the impact of livestock farming and ranching on aquatic insect abundance and richness.
• Focus on five major aquatic insect orders: Ephemeroptera, Plecoptera, Trichoptera, Megaloptera, and Odonata.

Main Methods:

• Conducted a meta-analysis of existing studies.
• Examined the effects of livestock farming on species richness and abundance.
• Accounted for moderators like livestock type, riparian vegetation, and stocking density.

Main Results:

• Livestock farming significantly reduced species richness for Ephemeroptera, Trichoptera, and Plecoptera.
• No significant overall impact of livestock farming on the abundance of aquatic insects was found.
• Apparent stability in abundance with richness decline suggests community composition shifts.

Conclusions:

• Livestock farming negatively impacts aquatic insect species richness.
• Further research with finer taxonomic resolution and detailed data is needed.
• Understanding livestock's heterogeneous effects is crucial for predicting future impacts.