Habitat Quality Assessment Within Expanded Ranges of Dengue Vectors Using a Composite Index Scale

Area of Science:

• Ecology and Environmental Science
• Vector-borne Disease Epidemiology
• Climate Change Impact Assessment

Background:

• Climate change is altering species distributions, impacting disease vector populations and their geographic ranges.
• Assessing habitat quality in newly suitable areas is crucial for accurate disease vector risk evaluation.
• Understanding the long-term viability of mosquito populations in expanded ranges under future climate scenarios is a critical research gap.

Purpose of the Study:

• To project habitat suitability and quantify habitat quality for Aedes aegypti and Aedes albopictus mosquitoes across historical and future climate scenarios in Asia.
• To introduce and validate a Composite Index Scale (CIS) for a refined assessment of habitat quality relevant to disease vector populations.
• To evaluate the potential increase in disease transmission risk associated with shifts in mosquito habitat suitability.

Main Methods:

• Utilized MaxEnt modeling to project habitat suitability for Aedes species under historical and future climate scenarios (SSP1-4).
• Developed and applied a Composite Index Scale (CIS) incorporating bioclimatic suitability, habitat changes, niche breadth, niche position, and range shifts.
• Quantified vulnerable habitat areas (km²), comparing past baselines with future projections using a ≥0.5 suitability threshold.

Main Results:

• Past vulnerable habitat for Aedes aegypti was 1,698,972 km² and for Aedes albopictus was 1,328,577 km².
• Future projections indicate an increase in vulnerable suitable habitat for Aedes aegypti to 1,991,596–2,220,554 km² and for Aedes albopictus to 1,589,240–1,734,846 km² by the end of the 21st century.
• The CIS indicated improved habitat quality in 12 out of 16 scenarios for Aedes aegypti and high vulnerability in 10 out of 16 scenarios for Aedes albopictus, correlating significantly with vulnerable pixel counts.

Conclusions:

• The Composite Index Scale (CIS) provides a robust measure for assessing habitat quality and associated disease vector risks.
• Projected increases in suitable and quality habitats for Aedes aegypti and Aedes albopictus suggest an elevated risk of dengue transmission.
• Effective habitat quality assessment is essential for predicting and mitigating the impact of climate change on vector-borne disease dynamics.