Table 2 Land-use classes derived from VHR imagery, with suggested open alternatives, and knowledge relating to their influence on larval habitat suitability (from literature and experts)
Land-use classes from VHR imagery | Alternative existing open product(s) | Larval habitat suitability—Sub-Saharan African cities | Larval habitat suitability—Dakar |
|---|---|---|---|
High-density planned residential areas | WUDAPT LCZ | Breeding sites are more frequent in planned sparsely built-up areas than in planned densely built-up areas [8, 56] | In densely built-up areas, the number of potential breeding sites is reduced compared to areas that have a lower density of buildings [21] |
Low-density planned residential areas | WUDAPT LCZ | ||
Deprived residential areas | n/a (WUDAPT LCZ) | An increasing proportion of urban residents live in unplanned settlements where the lack of services (e.g., sanitation, drainage) and unfavourable siting (e.g., in lowlands) may contribute to the emergence of breeding sites. [68, 69]. Breeding sites are commonly found in deprived areas, including slums [8, 9, 70] | Dakar's suburbs include non-structured urbanized areas located in depressions and lowlands, with a shallow water table. These areas are prone to flooding and hence to the proliferation of larval habitats [71]. Garbage and sewage disposal services are available for most residents, but in some areas solid waste can cause clogged drains [28, 68] |
Non-residential built-up areas | WUDAPT LCZ | Breeding sites are characteristically located close to human habitations [64] and can therefore be expected to be less frequent in non-residential areas | Breeding sites tend to be located close to human dwellings rather than in uninhabited areas [28] |
Agricultural areas | Esri 2020 Land Cover, WorldCover | In general, factors that are favourable to agriculture are also favourable to the presence of larvae, e.g., lowlands, clayey or loamy soils with low runoff and the presence of water bodies [72]. Moreover, irrigation of urban and peri-urban agricultural land has led to the emergence of larval habitats [61, 73, 74] and features such as trenches, irrigation wells, water tanks, ditches etc. provide good conditions [9, 61, 67, 75]. An. gambiae is likely to develop resistance to insecticides used in agriculture [63, 76] | Market gardening is very developed in and around Dakar, particularly in the Niayes area. The presence and abundance of larvae is lower in water collections located in market gardens than in surrounding areas, possibly due to the presence of larvivorous fish and pesticides [28, 34] |
Non-agricultural vegetated areas | Esri 2020 Land Cover, WorldCover | An. gambiae usually breeds in sites where there is no upright vegetation [33] | Breeding sites tend to be located close to human dwellings rather than in uninhabited areas [28] |
Non-agricultural areas with sparse or no vegetation | Esri 2020 Land Cover, WorldCover | Puddles are typical breeding sites. They can form in tyre tracks, potholes, footsteps and hoofsteps on bare ground or sparsely vegetated areas [9, 33, 59] | Breeding sites tend to be located close to human dwellings rather than in uninhabited areas [28] |
Wetlands | Esri 2020 Land Cover, WorldCover | Wetlands/swamps are natural breeding sites often cited in the literature as potential habitats [9] | Urban wetlands are typical larval habitats [77] |