Understanding landscape barriers to pathogen transmission requires evaluating how landscape characteristics, such as the spatial configuration of habitat and roads, rivers and fences, affect the distribution of key wildlife hosts.
Because observed densities of hosts are a combination of changes in abundance and changes in habitat selection by individuals, we will advance previous work by collecting individual-level data on movements of the primary tick reproductive host (i.e deer), enabling us to quantify:
(i) how habitat selection by deer changes across landscape structure (key WP2 & 3 inputs)
(ii) how deer movement between habitats impacts the distribution of tick-borne pathogens and hazard to humans;
(iii) how deer behave in different habitats that may affect ticks.
H1.1. Tick presence and density will be positively affected by habitat use and behaviour of deer due to their role in feeding adult ticks and recruitment of larval ticks.
H1.2. The prevalence and diversity of Bbsl among woodland patches will increase with patch size and with greater ecological connectivity for deer, small mammals and bird transmission hosts.
H1.3. Bbsl genomic population structure will decrease with greater ecological connectivity.
Study landscapes and existing data: Two mixed woodland-farmland landscapes, (New Forest area extending into S. Wiltshire, and Aberdeenshire) are selected capturing a gradient of woodland patch sizes and connectivity, including potential environmental barriers and human usage, with substantial pre-existing data. The New Forest is a hotspot for human LD cases, reflecting human recreational use, high deer populations and high infection prevalence (NIP) in ticks, dominated by bird-associated genospecies of Bbsl (up to 30%). It is also a key emerging UK focus of TBEV (WP2).
Woodlands in the New Forest are undergoing restoration and expansion. Agricultural habitat between fragmented woodlands is subject to new environmental land management (ELM) schemes to increase habitat connectivity. Aberdeenshire is also a LD hotspot, with dense populations of primarily roe deer, and high variance in Bbsl tick infection prevalence (up to 20%), dominated by small mammal-associated geno-species7. Aberdeenshire has targets to increase woodland extent by 40% by 2050, to increase habitat networks and human access.
