Ixodid tick diversity and distribution across forest-fringe landscapes of the Western Ghats, India, with emphasis on Kyasanur Forest Disease vectors

The Western Ghats of India support a diverse assemblage of Ixodid ticks, including multiple vectors of Kyasanur Forest Disease (KFD), yet comprehensive data from forest-fringe landscapes outside recognised outbreak zones remain limited. To address this gap, we undertook a multi-state, cross-sectional survey across 44 forest-fringe villages distributed within seven ecological grids spanning Goa, Maharashtra, Karnataka, Kerala, and Tamil Nadu during peak nymphal activity (December–February). Standardized flagging method yielded 10,350 ticks representing 24 taxa across four genera, including 12 recognised KFD vectors. Haemaphysalis spinigera and Haemaphysalis turturis were the most abundant and widespread species in both historically affected and unaffected districts, indicating that ecological suitability for primary vectors extends substantially beyond the spatial extent of human case reporting. Species richness, Shannon diversity, Simpson diversity, and total abundance exhibited pronounced spatial heterogeneity, with multiple villages in Karnataka and Kerala supporting the highest diversity, while clusters in Goa and Maharashtra exhibited depauperate assemblages dominated by one or two Haemaphysalis species. These community patterns suggest fine-scale variation in habitat suitability within forest-fringe mosaics shaped by land-cover transitions and vegetation structure. Joint Species Distribution Modelling (JSDM) revealed that tick assemblages respond to interacting climatic, habitat, terrain, and temporal gradients. Precipitation, NDVI-derived vegetation structure, land-cover categories, slope-derived terrain metrics, seasonal timing, and inter-annual variation collectively influenced species distributions, demonstrating multidimensional environmental filtering. Distinct and sometimes contrasting predictor–response relationships among taxa highlight niche differentiation within the tick community. Moderate residual correlations among several species pairs further indicate shared habitat preferences or unmeasured ecological processes such as host movement patterns, understory complexity, and microhabitat moisture retention. Together, these findings provide the most geographically extensive ecological assessment of Ixodid ticks in the Western Ghats. The widespread distribution of multiple KFD vectors in districts without confirmed human cases, underscores the urgent need for proactive ecological surveillance, integration of fine-scale environmental data, and landscape-based risk forecasting. Strengthened surveillance frameworks incorporating habitat metrics, host information, and pathogen screening will be critical for anticipating shifts in vector distributions and mitigating emerging tick-borne disease threats in the region.