🌍 Big Problem: Biodiversity Loss

• Humanity has already crossed 5 of 9 planetary boundaries (climate change, biosphere integrity, land change, pollution, nutrient cycles).
• We’re in the sixth mass extinction: corals 🪸, bees 🐝, bats 🦇, amphibians 🐸 are disappearing.
• Ecosystem collapse threatens the “One Health” link between environment, animals, and humans.

🦠 Enter the Microbiome

• Every plant/animal is a holobiont: host + its microbiome.
• Healthy microbiomes = resilience, balance, disease resistance.
• Disturbance (pollution, warming, etc.) → dysbiosis (loss of diversity, more pathogens, antibiotic resistance).

🌱 Microbiome Stewardship = taking care of ecosystems by managing their microbes.

• Use probiotics, synbiotics, microbial transplants, biofertilizers, biopesticides to restore balance.
• Goal: keep ecosystems functioning → fewer pandemics, healthier hosts, more biodiversity.

🧪 Examples of Probiotic Use in Nature (Box 1 highlights):

• Humans: Fecal microbiota transplants (FMT) for C. difficile, probiotics for infants.
• Plants: Biopesticides, biofertilizers, biostimulants (Bacillus, Pseudomonas, Rhizobium).
• Aquaculture: Replace antibiotics with probiotics (e.g., Pediococcus acidilactici).
• Bees: Lactobacillus spp. stabilize gut, improve survival under stress.
• Corals: Probiotics boost heat tolerance, resist oil spills & pathogens.
• Amphibians: Skin probiotics protect against chytrid fungus.

⚙️ How to Design Probiotics for Ecosystems

1. Discovery: find beneficial microbes (native, adapted strains).
2. Screening: test their effects (multi-omics, mode of action).
3. Formulation: make stable products (sometimes consortia > single strain).
4. Application: deliver at right dose, form, and method.

⚠️ Risks & Safety Concerns

• Regulations differ (FDA vs EFSA).
• Hard to test live microbes (ever-changing physiology).
• Risk: a probiotic strain might dominate, reduce diversity, or affect non-target species.
• But risk of inaction may be worse (e.g., coral reef collapse, bee loss).

📚 Lessons from Other Fields

• COVID-19 vaccines: rapid, global collaboration despite unknown risks.
• FMTs: not risk-free but save lives.
• Wolbachia in mosquitoes: reduces spread of malaria, dengue, Zika.

⚖️ Ethical Considerations

• Who decides to release probiotics into ecosystems? Scientists? Local communities? Governments?
• Could helping bees harm flowers? Could coral probiotics affect fish?
• Balance responsibility vs urgency: waiting too long may mean losing ecosystems forever.

🛠️ Evidence-Based Framework (Fig. 2)

1. Assess risks/benefits, compare with alternatives.
2. Select safe, preferably native microbes.
3. Define effective dose (minimal disturbance).
4. Choose delivery system (water, food, topical).
5. Test effects on non-target species in pilot trials.
6. Define risks, economic, cultural, and societal values.
7. Scale up only if benefits > risks.

🔮 Future Perspectives

• Time is running out ⏳.
• Need microbiome banks & networks (like “microbiota vaults”) to share resources.
• Policies should allow fast but safe action.
• Microbiome stewardship = powerful tool to save biodiversity 🌍🦠🦋🐠.