Effects of Japanese Barberry (Ranunculales: Berberidaceae) Removal and Resulting Microclimatic Changes on Ixodes scapularis (Acari: Ixodidae) Abundances in Connecticut, USA

Abstract

Japanese barberry (Berberis thunbergii de Candolle) is a thorny, perennial, exotic, invasive shrub that is well established throughout much of the eastern United States. It can form dense thickets that limit native herbaceous and woody regeneration, alter soil structure and function, and harbor increased blacklegged tick (Ixodes scapularis Say) populations. This study examined a potential causal mechanism for the link between Japanese barberry and blacklegged ticks to determine if eliminating Japanese barberry could reduce tick abundance and associated prevalence of Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt, and Brenner). Japanese barberry was controlled at five study areas throughout Connecticut; adult ticks were sampled over three years. Each area had three habitat plots: areas where barberry was controlled, areas where barberry remained intact, and areas where barberry was minimal or absent. Sampled ticks were retained and tested for B. burgdorferi presence. At two study areas, temperature and relative humidity data loggers were deployed in each of the three habitat plots over two growing seasons. Intact barberry stands had 280 ± 51 B. burgdorferi-infected adult ticks/ha, which was significantly higher than for controlled (121 ± 17/ha) and no barberry (30 ± 10/ha) areas. Microclimatic conditions where Japanese barberry was controlled were similar to areas without barberry. Japanese barberry infestations are favorable habitat for ticks, as they provide a buffered microclimate that limits desiccation-induced tick mortality. Control of Japanese barberry reduced the number of ticks infected with B. burgdorferi by nearly 60% by reverting microclimatic conditions to those more typical of native northeastern forests.

Control of bush encroachment in Borana zone of southern Ethiopia: effects of different control techniques on rangeland vegetation and tick populations

“…The study results suggest that A. mellifera and A. drepanolobium encroachment provides a conducive environment for the survival of ticks which is in line with Bertrand and Wilson (1996) who reported that ticks in open fields suffered higher mortality rates than those in canopied habitats. A previous study by Scott and Jeffrey (2010) found that adult tick density was positively correlated with percent coverage of live Japanese barberry. Adult-stage tick density was increased by 1,111.1 ha −1 after the control actions only in the control plot (T5) probably due to their ability to escape from the plots that were cleared off encroaching trees/shrubs species to the plots that were untouched, i.e.…”

Evidence for Personal Protective Measures to Reduce Human Contact With Blacklegged Ticks and for Environmentally Based Control Methods to Suppress Host-Seeking Blacklegged Ticks and Reduce Infection with Lyme Disease Spirochetes in Tick Vectors and Rodent Reservoirs

“…Silt fence barriers, made from polypropylene plastic fabric, were shown to reduce the abundance of I. scapularis adults, but not nymphs, in pastures (Carroll and Schmidtmann 1996). Two woodland studies in Connecticut showed that removal of the invasive Japanese barberry ( Berberis thunbergii de Candolle) shrub, which previously was found to be associated with elevated abundance of host-seeking I. scapularis in Maine (Lubelczyk et al 2004, Elias et al 2006), could substantially reduce the abundance of host-seeking I. scapularis adults as well as B. burgdorferi -infected adults (Williams et al 2009, Williams and Ward 2010). Other studies have demonstrated strong negative impacts of burning or mowing on the abundance of host-seeking I. scapularis adults (Rogers 1953, Wilson 1986, Gleim et al 2014).…”

Methods to Prevent Tick Bites and Lyme Disease

“…These approaches include removal of specific plants associated with increased tick abundance like Japanese Barberry; use of herbage that is less attractive to deer such as ferns, native grasses, and unpalatable tree species such as spruce; and desiccant barriers (gravel or wood chips) at the boundary of high-(forest edge) and low-risk zones (lawns). 71,97 Finally, tick unfriendly zones can be created by integrating landscape structures (eg, a raised deck) and management practices (eg, grass cutting, scrub removal, xeriscaping). An excellent summary of vegetation management for tick control is provided in Ref.…”