We face higher temperatures, different precipitation patterns and more extreme weather conditions because of climate change. The landscape is also changing: The delta faces salinization, and we are creating additional water buffers to cope with floods. Mosquitoes, which can carry viruses, thrive in these warmer and wetter landscapes. But there has not been sufficient research into the links between environmental changes, landscape management, the ecology of arthropods, animals and human health.

Approach

• We will develop scenarios where groundwater salinization, salt intrusion in surface water and the delta, land-use modifications, and surface-water temperatures relate to ideal mosquito habitats.
• We will study the impact of salinization and the climate on four globally important mosquito species. These mosquitoes carry viruses and are also present in the Netherlands.
• We will research how water landscape management influences the distribution of different types of birds and explore whether these developments will contribute to the transmission of viruses to urban areas.
• Lastly, virus and animal ecology experts will explore innovative methods of ‘bird distraction’.

A joint risk analysis for public health in the Rotterdam urban delta will be conducted with our partners and stakeholders.

Background

The combination of water-rich landscapes, exotic mosquitoes, busy international trade and travel and high population density makes the low-lying delta in the Netherlands vulnerable to future outbreaks of exotic infectious diseases. Besides increase in temperature and extreme rainfall events and droughts, climate change is presenting additional risks. One of these risks comes from increasing salinization as a result of sea level rise. Rapid sea level rise is a threat resulting from climatic change threat, which results in increasing salinization of coastal areas with large expected impacts on biodiversity and land use, and thereby on mosquitoes and birds. At the same time, the Dutch constitutes an ideal model system to study impacts of salinization of vector borne disease.

The combination of these three key Climate Change related changes will likely impact disease risk in urban deltas, as it will impact greatly on the habitat for birds (more brackish wetlands, “ruimte voor de rivier”), mosquitoes (novel habitat) in an area, where international transport and trade leads to continuous introduction of novel vectors and pathogens. The joint impact of all these factors shapes the ‘pathogenic landscape’. Using the unique setting of the Dutch delta this project will be a true frontrunner for other deltas at slightly higher levels of elevation (Fig 2). As such, lessons learned in the current project are likely of great use for future developments in other delta regions.

Aims

In this PDPC frontrunner project we aim to answer the overall research question:

“How will mosquito and bird and pathogen populations be affected by climate change, changes in water management and increasing salinization in a densely populated delta, and how will this ultimately impact on disease risk?”

This will be done by connecting the fields of climate change modelling, landscape ecology, animal ecology, insect ecology, virology and public health.

These findings will require new mitigation measures for the delta, from building with nature solutions to hard infrastructure such as locks and gates to mitigate the anticipated increase in salt intrusion.

This frontrunner project will consist of 4 working packages.

WP1 (lead TU Delft) will build upon the scenario’s for water management and land use change as developed within the NWA OneHealth PACT project (One Health PACT)  and in the NWO Perspective Program Salt intrusion through urbanising deltas: solutions (‘SALTISolutions’) and coupled them with climate change scenarios.

In WP2 (lead LU, co-lead WUR & EMC), we will focus on past, present and future impacts of salinization and climate on four globally important, locally present mosquito species, each of them acting as a vector for a range of pathogens.

In WP3 (lead ErasmusMC, co-lead UvA), the effect of wetland development on bird species distribution and potential transmission of viruses to urban areas will be explored. This will be done by modelling historical data on landscape changes (wetland development) and bird species abundance data (SOVON).

WP4 (All Partners) is the synthesis work package that aims to combine key data streams and information from WP 1, 2 and 3, which will be validated and combined. This will result in an assessment of the risk of vector borne disease outbreaks in humans, using data generated in WP2 and 3, under the scenarios as developed under WP1 and the OH-PACT project.

Figure 1.  The projected changes in salinization of water bodies are expected to impact on disease risk (red box) via changes in birds and mosquitoes. The yellow box indicates the abiotic changes, and the human interventions in the landscape; the green box indicates the biotic consequences and the ultimate impact on disease risk. Each of the work packages focuses on a subset of the cascade of effects, as shown on the right side of the figure.

Figure 2. The ultimate aim of the current proposal is to use the knowledge on the Rhine delta in other parts of the world. Examples above show deltas that share a number of similar characteristics to the Rhine delta, in terms of population density, size and vulnerability to salinization and vector borne disease outbreaks.