A framework to map abundance of tick metapopulations

This paper further explores a previously developed spatially explicit model that incorporates the effects of habitat topology and abiotic (climate) suitability on tick population density. The primary focus was to provide a parameterization of host dispersal, which is involved in the calculation of two critical parameters of the model, namely patch Traversability and Recruitment. We used a dispersal kernel that can accommodate a variety of dispersal patterns, varying the proportion of dispersing hosts as a function of patch size (vv), and the dispersing range of hosts (r  ). Model values were compared with a set of tick densities from an actual landscape. Correlations were very poor for low vv and r, but greatly improved (R = 0.8–0.96, p = 0.0001) for high values of these parameters. This suggests the significance of long-range dispersers to keep this actual network of tick metapopulation patches. Further results of the dispersal kernel hint at the importance of short-range hosts in the maintenance of neighbouring, small, well-connected patches.This abundance model involving climate suitability, habitat topology and host dispersal contributions, was applied to the tick Ixodes ricinus in a large area of northern Spain. The Recruitment at the patch level was calculated and used to forecast abundance of ticks across the study area. Sensitivity of every patch was defined as the response-range of Recruitment to quantitative changes in climate and topological features of the patch. To show how changes in the patch characteristics can dramatically alter the landscape composition and thence tick abundance, simulations were conducted in which the real landscape was modified by removing patches based on selected habitat features. The ecosystem was affected to the greatest extent by removal of patches of high sensitivity, large size, and high Recruitment. The proposed framework has particular utility for epidemiological studies aimed at evaluating the impact of climate change or habitat management on the survival of tick populations, and the health risks posed by ticks.