Land use change is an important driver of both biodiversity loss and zoonotic disease transmission in tropical countryside landscapes. Developing solutions for protecting biodiversity, public health, and livelihoods in working landscapes requires understanding the spatial scales at which habitat characteristics such as land cover shape biodiversity, especially for arthropods that transmit pathogens. A growing body of evidence shows that species richness for many taxa correlates with tree cover at small spatial scales of <100 m, indicating that local tree cover management is a promising conservation tool. To investigate whether mosquito species richness, community composition, and presence of specific disease vector species respond to tree cover—and if so, whether at spatial scales similar to other taxa—we surveyed mosquito communities along a tree cover gradient and across agricultural, residential, and forested land uses in rural southern Costa Rica. We found that tree cover was both positively correlated with mosquito species richness and negatively correlated with the presence of the common invasive dengue vector Aedes albopictus, particularly at small spatial scales of 80 – 200m. Beyond tree cover, land use type predicted community composition and Ae. albopictus presence, but not species richness. The results suggest that preservation and expansion of tree cover at local scales can protect biodiversity for a wide range of taxa and also confer protection against disease vector occurrence.

Field-caught mosquitoes captured from sites with varying land uses and land cover in southwestern Costa Rica were identified by DNA sequencing and morphologically (Aedes genus only). The file "SpeciesSiteData_CRMosquitoes_4Dec2023.csv" contains, for each site included in the survey, presence-absence data for each species observed, and environmental variables relating to land use, tree cover, and climate. Land use categories, GPS coordinates, and elevation were recorded by the field team at the time of sample collection. Tree cover values were calculated from a raster of fine-scale tree cover created by Echeverri et al., available at https://doi.org/10.5061/dryad.1ns1rn8w7. Mean annual temperature was extracted from the WorldClim bioclim dataset (https://www.worldclim.org/data/worldclim21.html). The file "OTUSequences_8Feb2021.csv" contains the cleaned DNA sequences, grouped by OTU, that were used for taxonomic identification.

Funding provided by: National Institutes of HealthCrossref Funder Registry ID: https://ror.org/01cwqze88Award Number: R35GM133439 Funding provided by: National Science FoundationCrossref Funder Registry ID: https://ror.org/021nxhr62Award Number: DEB3322011147 Funding provided by: National Institutes of HealthCrossref Funder Registry ID: https://ror.org/01cwqze88Award Number: R01AI102918 Funding provided by: National Institutes of HealthCrossref Funder Registry ID: https://ror.org/01cwqze88Award Number: R01AI168097