A forest, its edge and the hedgerow bordering a field do not form a uniform environment for ticks. It is at this fine scale that a tool presented by INRAE on 31 August 2026 aims to estimate their abundance more accurately. The subject remains relevant in autumn: knowing which environments are favourable helps us understand exposure, but does not allow us to predict what will happen to an individual walker.
The key point lies in the word “abundance”. The model describes the relative distribution of ticks across a bocage agricultural landscape. It does not provide a diagnosis or an individual’s probability of contracting a disease after an outing.
Research rooted in two French regions
According to INRAE’s press release, researchers from INRAE and CNRS drew on three years of sampling in the Armorique and Pyrénées-Garonne experimental zones, in Ille-et-Vilaine and Haute-Garonne respectively. Nearly 12 000 Ixodes ricinus nymphs were collected during the spring peaks in activity.
These observations were used to link variations in density to landscape and weather characteristics. The model distinguishes forests from forest edges and hedgerows. In the latter, estimated abundance increases with the forest perimeter and decreases, in particular, with distance from the forest.
The prototype is presented as open and adapted to bocage landscapes under the climatic conditions of mainland France. The research has been published in “Basic and Applied Ecology”. It could help assess the consequences of land-use changes; the press release does not demonstrate local validation for every European region.
Why landscape shape matters
A hedgerow is not just a line on a road map. When studying a living organism, its proximity to other habitats and the conditions it encounters there can matter. This is precisely what is lost when the landscape is viewed only in broad categories such as “countryside” or “forest”.
The ECDC factsheet on Ixodes ricinus, updated in July 2014, describes a species that is sensitive to humidity and found in wooded areas and other habitats that are favourable to its hosts. It explains that the tick waits for an animal to pass on the vegetation, then descends into the leaf litter to rehydrate.
This biology helps explain why two nearby places can offer different conditions. It does not, however, allow us to infer the number of ticks in a garden simply by looking at its vegetation. Observing an environment and measuring a population are two distinct kinds of information.
The life cycle comprises the egg, larva, nymph and adult stages. The ECDC says that the feeding stages use different hosts, including mammals and birds. The relationship between landscape and ticks therefore also involves the animals that frequent it.
What a simulation can help us ask
A model is useful because it makes relationships explicit and allows defined situations to be compared. A local authority or research team can thus ask a more precise question than “is this landscape dangerous?”: which areas have conditions associated with higher abundance, according to the data used?
The answer depends on the scope of the study. The samples described here consist of nymphs and were collected during spring peaks. They should not be turned into a permanent count of all life stages, in every season, in every country.
Nor is the number of specimens collected a number of people who have fallen ill. That confusion would completely change the meaning of the result. Moving from the presence of a vector to human disease involves other factors, including the presence of a pathogen and exposure that allows it to be transmitted.
An abundance map is not a map of personal risk
An area ranked lower in an estimate is not necessarily free of ticks. Conversely, a favourable area does not mean that everyone who passes through it will be bitten or infected. The map describes a phenomenon at a certain scale; an individual’s circumstances cannot be reduced to the colour of an area.
This distinction also guards against drawing an excessive conclusion about hedgerow management. The work presented is not a general instruction to uproot hedgerows. Using a simulation to study land-use changes means examining the context, objectives and other consequences, rather than making a single decision on the basis of one indicator.
Perhaps the most useful takeaway for the general public is this shift in perspective: forest edges and transitions between habitats deserve attention. From an ecological point of view, the forest does not end at the boundary drawn on a map.
Precautions remain useful in autumn
The government prevention page, updated on 14 August 2026, notes that activity is particularly pronounced in spring and autumn, while ticks may be present all year when conditions are mild.
It recommends wearing long, covering clothing, using an approved repellent suitable for the person, and checking carefully after returning. The product’s age and usage instructions matter, particularly for children and pregnant women. If a tick is attached, it should be removed promptly with a suitable tool, without applying any product to it beforehand, and the area should then be monitored. An expanding redness, fever or persistent symptoms warrant medical advice.
These steps address a concrete situation. The model, for its part, improves how a landscape can be studied. The two approaches complement each other, provided neither is asked to establish what it cannot.
Illustration photo: a female Ixodes ricinus photographed in Germany in May 2021, not a specimen collected in either of the study areas.
