Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes

Abstract

BackgroundThe castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers.ResultsMany drivers had, on their own, either a moderate or small explanatory value for the abundance of I. ricinus, but combined they explained a substantial part of variation. This emphasizes the complex ecology of I. ricinus and the relevance of environmental factors for tick abundance. Macroclimate only explained a small fraction of variation, while properties of macro- and microhabitat, which buffer macroclimate, had a considerable impact on tick abundance. The amount of forest and the composition of the surrounding rural landscape were additionally important drivers of tick abundance. Functional (dispersules) and structural (density of tree and shrub layers) properties of the habitat patch played an important role. Various diversity metrics had only a small relative importance. Ontogenetic tick stages showed pronounced differences in their response. The abundance of nymphs and adults is explained by the preceding stage with a positive relationship, indicating a cumulative effect of drivers.ConclusionsOur findings suggest that the ecosystem disservices of tick-borne diseases, via the abundance of ticks, strongly depends on habitat properties and thus on how humans manage ecosystems from the scale of the microhabitat to the landscape. This study stresses the need to further evaluate the interaction between climate change and ecosystem management on I. ricinus abundance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-017-0141-0) contains supplementary material, which is available to authorized users.

High ecosystem service delivery potential of small woodlands in agricultural landscapes

“…Tick‐borne disease risk is, however, lower, likely due to decreased larval densities in the unfavourable (e.g. hotter and drier) microclimatic conditions at the edge (Ehrmann et al, ).…”

The scale affects our view on the identification and distribution of microbial communities in ticks

“…These corridors explain the routes that mammals and birds use to move across the matrix of suitable and unsuitable habitat [99]. Therefore, a specific type of vegetation may be suitable for a high abundance of a given reservoir, therefore feeding ticks that could result infected with TBPs carried out by such reservoir [100]. However, the movements of the reservoirs across the matrix of the landscape patches could explain the variable rates, at the micro-spatial scale, of the prevalence of pathogens.…”

Management Options for Ixodes ricinus-Associated Pathogens: A Review of Prevention Strategies

“…Ixodes ricinus is an exophilic tick that actively quests for hosts and consequently, its presence is strongly associated with specific biotope and climatic conditions. Typical habitats where I. ricinus are present tend to be lowland, relatively humid biotopes such as unmanaged grasslands, heaths, forest edges, woodlands, and broad-leaf forests with sufficiently dense undergrowth [23]. Key climatic factors influencing tick activity include air and soil temperature, air and soil humidity, and solar radiation [21,[24][25][26].…”