Data from: One questionnaire - two points in time: Has plant species knowledge of laypeople changed over a period of 20 years?

Concern has been raised that in recent decades knowledge of plant species
has severely declined in western countries. However, in the absence of
regularly repeated and standardized surveys, no reliable statement can be
made as to whether plant species knowledge has actually declined in recent
decades. The present study aimed to contribute to filling this knowledge
gap by repeating a survey on the knowledge of plant species twenty years
later. Laypeople (all adults) were asked to identify 15 common wild plant
species of Germany, which were presented to them as photographs. Based on
previous research, five of the 15 species were considered well-known, five
moderately known, and five rather unknown to laypeople. The original
survey was conducted in 2002 at two locations in the city of Marburg,
while its repetition took place in 2022/23, both in Marburg (identical
location) and the city of Freiburg, as well as online. In total, 1558
individuals (18-88 years old) participated in the surveys. Participants
identified, on average, 6.5 plant species correctly. Plant species
knowledge did not decrease between 2002 and 2022/23, increased with age
and the number of sources of plant species knowledge used, and was higher
for women than men. The older the participants, the more likely they were
to name gardening and other leisure activities as their sources of
knowledge of plant species, and the less likely they were to name family
and education. Although we did not find evidence for a decline in
knowledge of plant species, the public showed a poor ability to identify
plants (average identification of about 40 % of the species shown),
indicating a disconnection from nature that may negatively affect
society᾿s support for efforts to conserve biodiversity. Policy should thus
aim to increase personal experience with plants from a young age to foster
a better understanding of biodiversity.