摘要

1. 'Conservation planning and ecological analyses require large-scale data on species' abundance and distribution. We describe a national effort to quickly establish the distributions of taxa with hard-to-identify adults but easily identifiable larval stages: cynipid gall wasps (Hymenoptera: Cynipidae, Cynipini) on oak (Quercus robur). 2. The survey was implemented by volunteers across 239 sites over 687 km of latitude. It yielded 10 523 galls, which were identified by specialists. The material revealed two species new to Finland and the national distributions and local abundances of 16 species. 3. The likelihood of finding a given species was significantly affected by the visual apparency of its galls. This suggests that some cryptic generations may have been missed in the sampling. 4. At the national level, our study exposed systematic changes in the species richness of insect taxa associated with a patchily distributed host plant towards its range margin. Species' incidences decline as host trees grow increasingly scattered within the landscape. 5. From a conservation perspective, the data increased eight-fold the known records of gall wasps from Finland, and informed the first assessment of national threat status of these taxa. 6. Our study reveals how the efforts of the public may be efficiently harnessed for revealing the current status of poorly known taxa. In addition to delivering a first survey of the target taxa, and of factors affecting their distribution, such 'citizen science' may generate a permanent base of enthusiasts for the future monitoring of changes and trends.

  • 出版日期2016-1