A study at three spatial scales

The field work was carried out in the provinces of Östergötland and Småland, throughout most of Thesium alpinum's range in Sweden. Habitat characteristics were recorded at three spatial scales.

Plant scale

Each host plant was checked for Canthophorus impressus and the number of adults and nymphs was noted.
As a measure of individual plant quality, a set of habitat variables were recorded:

• summed length of branches
• cover of bare ground
• vegetation height
• sun exposure
• aspect and inclination of slope
• number of plants in 1 m radius circle

Patch scale

A patch was defined as a group of plants separated from other plants with at least 55 m. On this spatial scale, one variable was recorded:

• number of host plants

Landscape scale

Circular landscapes with radii of 1 km were placed in the study area, each centred on a previously known population of Thesium alpinum. In total, 30 landscapes were studied and the following variables recorded:

• number of host plants
• number of patches
• area of grasslands