Ground beetle (Carabidae) associations with UK Land Cover Map habitats

Biological records of carabid beetles were sourced from the NBN atlas. habitats are those from Centre for Ecology & Hydrology (CEH) Land Cover Map 2015 (LCM2015). Correlation indices were calculated for the carabids and habitats. A weighted version of the indices was calculated to allow the incorporation of carabid data from 100m squares that contain more than one habitat type.

The NBN does not include absence data. To allow us to have confidence that a species was genuinely not at a particular location, we counted the number of other species found in each location as a measure of survey effort, using a threshold value for the number of species taken into account before deciding on whether the target species could be considered absent. The NBN data contained a separate record for each species at each relevant 100 m location meaning that individual locations appeared multiple times. We created a version of the data with each location represented once, giving presence or absence (absences determined as described above) for each species at that location.

The datasets published include our recommended output, which shows habitat weighted analysis using an absence threshold of 14 other species. Versions with a threshold of seven and 28, and the unweighted versions of the analysis, are also included to allow the user to ascertain for themselves confidence in the association of a habitat to a species.