Drivers of tick community structure in a rhinoceros meta-population in Kenya

Understanding the structure and drivers of parasite communities including species assembly patterns, diversity, abundance, and aggregation is crucial in assessing the health of wild populations and the dynamics of host-parasite interactions within ecosystems. This study analyzed tick communities parasitizing the critically endangered black rhinoceros and the near threatened white rhinoceros metapopulation in twelve sanctuaries in Kenya. A total of 14,302 ticks from 20 tick species across four genera, Dermacentor (1 species), Rhipicephalus (8 species), Amblyomma (8 species) and Hyalomma (3 species) were sampled from 372 rhinoceroses. The most dominant species included Amblyomma gemma (23.28 %), Amblyomma sparsum (22.28 %) and Rhipicephalus pulchellus (18.94 %). Six tick communities were identified based on similarity in relative tick species composition. Mean NDVI and temperature were the major drivers of tick communities. Asymptotic Hill-Shannon and Hill-Simpson tick diversity metrics were 8.12 and 6.26 respectively for the Kenyan rhinoceros metapopulation. Species diversity varied between sanctuaries with Nairobi National Park (NNP) having the highest diversity (Hill-Shannon: 6.35, Hill-Simpson: 5.8) and Sera Rhinoceros Sanctuary (SER) the lowest diversity, (1.83, 1.69). The Intensive Protection Zone (IPZ) and Nairobi National Park had the greatest species richness (14 and 13 respectively), while Sera Rhinoceros Sanctuary had the lowest (2). Spatial heterogeneity in NDVI and species abundance were major drivers of species richness and Hill-Shannon species diversity. The number of ticks per rhinoceros was highly variable with a mean (SD) of 38.53 + 40.59 ticks per host, indicating strong tick aggregation among hosts. Significant positive interspecies correlations suggest a great role of host factors in tick infestation. Environmental factors, including temperature, NDVI, and rainfall, influenced tick abundance. Host-related factors, such as age, and sex, also played critical roles. This research improves our understanding of rhinoceros tick communities, diversity, and abundance patterns, with implications for tick control, tick-borne disease surveillance and rhino conservation in Kenya.