Forest fragmentation, anthropogenic land use, and climate shape sand fly community composition in central Panama
Year: 2026
Type: preprint
Abstract: Background American cutaneous leishmaniasis (ACL) is endemic in central Panama, where rapid land use change is transforming tropical landscapes and potentially altering the ecology of sand fly vectors. Although researchers have widely studied environmental determinants of individual vector species, community-level responses of sand fly assemblages to landscape modification remain poorly understood. We evaluated how landscape composition, fragmentation, climate, and topography influence sand fly community structure in a rural landscape of central Panama. Methodology/Principal Findings We combined metacommunity analyses with joint species distribution models (JSDMs) to quantify species-specific and community-level responses to climatic variables, land-cover composition, and forest configuration. We collected 1,692 individuals representing 30 species, including nine anthropportunist taxa of epidemiological importance. Sand fly assemblages had strong nestedness, low species turnover, and predominantly positive residual associations. Several anthropportunist sand fly species occurred across heterogeneous landscapes, although their responses to environmental conditions differed among taxa. Land-cover composition, forest fragmentation metrics, and elevation together explained about half of the variance in species occurrence and abundance, with the remainder attributed to climate and spatial, temporal, and community-level random effects. Grassland cover contributed most strongly to sand fly occurrence and abundance, whereas artificial surfaces consistently reduced both metrics. Fragmentation effects varied by species: edge density often increased occurrence and abundance, whereas more forest patches generally suppressed populations. Increased precipitation broadly enhanced occurrence and abundance, whereas higher temperatures negatively affected several taxa. Conclusions/significance Landscape heterogeneity predictably structures sand fly communities, and different forms of anthropogenic disturbance exert non-uniform effects on vector assemblages. The nested organization of these assemblages and the co-occurrence of several anthropophilic species suggest that multiple potential vector species may be present across heterogeneous landscapes. These findings highlight the need for landscape-informed surveillance and control strategies that prioritize grassland–forest interfaces and other disturbed ecotones where sand fly species of epidemiological importance frequently co-occur. Author summary American cutaneous leishmaniasis, a vector-borne disease, remains common in Panama and other parts of Latin America. Sand flies transmit the parasites that cause this disease, and deforestation, agriculture, and urban expansion are rapidly changing their habitats. We sampled sand flies in rural communities across central Panama to investigate how climate, land cover, and forest fragmentation shape sand fly communities. Environmental conditions were associated with differences in species composition and abundance. Grasslands and forest edges were associated with higher numbers of some sand fly species, whereas more urbanized areas generally supported fewer sand flies. Sand fly communities showed a nested structure, meaning that species-poor sites tended to contain subsets of the species found in richer sites. Several species of potential epidemiological importance occurred across different landscape conditions, although their responses to environmental change varied. These findings highlight the value of incorporating landscape characteristics into sand fly surveillance and identify disturbed habitats and forest–grassland interfaces as priorities for further ecological and epidemiological investigation. Studies incorporating sand fly infection status, host communities, and human exposure are needed to determine how these ecological patterns relate to Leishmania transmission.
Institutions: University of Georgia, Instituto Conmemorativo Gorgas de Estudios de la Salud, Indiana University Bloomington, Indiana University, Universidad de Panamá, Secretaría Nacional de Ciencia, Tecnología e Innovación, Smithsonian Tropical Research Institute, Wake Forest University, University of Nottingham
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7221760648