Abstract
Knowledge gaps on the dynamics of cattle fever tick-cattle-habitat-climate interactions in South Texas and their influence on the efficacy of treatments to eliminate infestations with the Rhipicephalus (Boophilus) microplus prevent optimal interventions by the Cattle Fever Tick Eradication Program (CFTEP). The CFTEP has been operating in the USA since 1907. This study applied the concept of location intelligence to examine movement, habitat use and selection by cattle in a highly heterogeneous coastal landscape infested with R. microplus. Cattle interface with white-tailed deer and nilgai, which are alternate wildlife hosts of R. microplus, in this unique South Texas landscape. Location intelligence data obtained from GPS collars placed on steers between August and December 2019 that were treated as part of the protocol to eradicate R. microplus were used to track their movement in the tick-infested rangeland of the Laguna Atascosa National Wildlife Refuge. GIS spatial analyses were conducted to determine time-of-day (morning, midday, evening, midnight), and seasonal differences in: (i) distance of cattle movements; (ii) cattle habitat use and selection; (iii) spatial spread of cattle; and (iv) distance to closest watering site. Cattle movement patterns, habitat use and selection, spatial spread, and distance to closest watering sites were significantly different between the summer and autumn periods. These variables were also significantly different by time-of-day periods within and between seasonal periods. Habitat use and selection by steers are discussed in the context of range sites and vegetation types. Nine ixodid tick species were documented through the inspection of hosts (cattle, nilgai, and white-tailed deer). Rhipicephalus microplus was collected from white-tailed deer and nilgai during cull hunts, as well as from project cattle that missed one anti-tick treatment due to adverse weather conditions. Tick-host-habitat-climate interactions involving cattle and wildlife, future grazing strategies for anti-tick treated cattle, and potential impacts of tick-refugia are discussed in the context of location intelligence. Spatiotemporal patterns of cattle habitat use and selection across an infested coastal landscape in South Texas revealed by location intelligence could inform adaptive operations of the CFTEP to keep the USA free of R. microplus.