Leading scholars in ethnobiology and ethnomedicine continuously stress the need for moving beyond the bare description of local knowledge (LK) and to additionally analyse and theorise about the characteristics and dynamics of human interactions with plants and related LK (e.g. [1–4]). Analyses of the variation of LK are thereby perceived as minimal standard [2, 3, 5]. Insights in the intracultural variation of knowledge help to identify the characteristics of more and less knowledgeable individuals , lead to hypotheses about the social organisation in a culture , give indications of persistence or loss of LK  and thereby help to identify the conditions for the thriving and vanishing of LK. Moreover, intracultural variation of knowledge is suggested to bear an important potential for informing adaptation processes in times of uncertainty .
So far, the intracultural variation of LK has been assessed in selected cultures and several regions of the world. . The type of knowledge and skills under investigation include plant species identification [7, 9], plant classification , knowledge of pests , and the use of plant species in diverse use categories, such as food, medicine, building material, firewood or domestic goods (e.g. [12–14]). The variables tested relating to these domains and skills include age [7, 10], gender [5, 13], family background , modernization [12, 15, 16], culture , geography , market access , education  and plant accessibility .
Although there is some diversity among the domains investigated, many studies concentrate on the intracultural variation of local medicinal knowledge (LMK) (e.g. [19–22]). These studies find that age has a positive relation with LMK, and it is only found to diminish towards the end of one’s lifetime . Gender differences in LMK are inconsistent between cultures and are suggested to depend, at least partly, on the cultural division of labour [22, 23]. Higher education is found to reduce LMK , while occupation is found to have varying effects, depending on the kind of occupation . Some studies also find that isolation is associated with high levels of LMK [25, 26], whereas modernization is associated with low levels of LMK [21, 27]. Other authors suggest that modernization does not influence LMK in this linear and straightforward manner (increasing modernization, decreasing LMK), but that the “nature of change may be subtle, complex, and specific to particular treatments” .
A few studies also compare the intracultural variation of knowledge concerning several different domains of knowledge [12–14, 16]. These studies find that the relation between peoples and domains of knowledge are complex and multilateral. E.g. among the Rarámuri people in Mexico, women know more plant species for medicinal uses, men are more familiar with plant species used for making domestic goods and for construction and both sexes hold similar knowledge about edible plants and firewood . Among the Roviana people of the Solomon Islands, modernization leads to increasing knowledge of the cash value of plant species, while it does not influence the knowledge in other domains . In south-western Spain a decline of traditional agricultural knowledge in general but a persistence of traditional livestock farming knowledge can be identified . And among the Shuhi people in southwest China, the accessibility to plant species influences not so much the selection of ritual and medicinal plant species, yet more the selection of plant species in other domains .
These results demonstrate the dynamic nature and intracultural variation of LK and show that the intracultural variation of LK is patterned following socio-demographic characteristics of informants, geographic characteristics as well as domains of knowledge. Reasons for the intracultural variation of LK are suggested to include the social organisation , distribution of work , and other cultural [14, 16, 20] as well as ecological factors [14, 20].
Although several studies on the variation of LK were conducted in several parts of the world, very limited information is available for Europe (notable exceptions: [16, 20]).
In this study we aim to (1) investigate the distribution and variation of wild plant knowledge relating to five domains of knowledge, (2) assess the relation of several socio-demographic and geographic variables to individuals’ wild plant knowledge, (3) identify reasons for the intracultural variation of knowledge, and (4) add European findings to the discussion on the intracultural variation of LK. The knowledge under investigation in this paper is commonly studied in ethnobiological research: wild plant knowledge. More precisely, our study concentrates on the respondents’ ability to recognise plant species under a shared name and to cite respective uses for every plant, independent from the respondents’ actual use, i.e. his or her behaviour.
While several of the variables and use categories chosen in this study were selected in former research (variables: gender, age, geography; use categories: food, drink, human medicine), we also investigated the variation of knowledge relating to variables and use categories unconsidered before (variables: farming, homegarden maintenance; use categories: veterinary medicine, customs).