Lasting Effects of Different Scaled Mass Mortality Events on Soil Microbial Communities

Area of Science:

• Ecology
• Soil Science
• Environmental Science

Background:

• Mass mortality events are increasing in frequency and magnitude.
• The long-term ecological effects of these events are understudied.
• Understanding these impacts is crucial for ecosystem management.

Purpose of the Study:

• To investigate the long-term effects of experimental mass mortality events on terrestrial ecosystems.
• To determine if key ecosystem properties remain affected 4 years after the events.
• To assess the influence of carrion biomass and nutrient addition on soil properties and microbial communities.

Main Methods:

• Experimental mass mortality events were simulated using varying biomass of feral swine carcasses or equivalent nutrients (N, P, K).
• Treatments included control, carrion, and nutrient additives, with and without scavenger access.
• Soil samples were analyzed for nutrient content (N, P, K, Ca) and microbial community composition after 4 years.

Main Results:

• Soil potassium (K) and calcium (Ca) significantly increased with increasing biomass.
• Microbial communities showed significant differences at higher biomass levels (182 kg) and between carrion and nutrient additive treatments.
• Soil nitrogen (N) did not differ significantly among treatments.

Conclusions:

• Experimental mass mortalities have lasting effects on soil nutrient composition, specifically increasing K and Ca.
• These events significantly alter soil microbial communities, with potential long-term consequences.
• The findings highlight the potential for cascading bottom-up effects on ecosystem structure following mass die-offs.