Ecology and conservation of blue ground beetles: from microhabitat use to landscape connectivity

The charismatic Blue ground beetle Carabus intricatus is the largest and one of the rarest species of ground beetle in the UK with a very restricted distribution, mostly on Dartmoor. However, relatively little is known about its biology, particularly specific (micro-)habitat requirements, population size and structure and foraging ecology. Such knowledge is essential in order to be able to implement successful conservation practices to boost populations.

Key questions that will be addressed include: How do Blue ground beetles utilize available habitat? Does this vary across years and different woodland sites? Do different life stages have different habitat requirements? How does the utilization of habitat change seasonally and why? How large are populations and how are they structured (sex, age)? How well connected/fragmented are these populations? How much competition is there between large carabid species? How important are climatic variables such as temperature, rainfall and humidity and food availability in explaining Blue ground beetle behaviour and ecology?

Field survey work of Blue ground beetles and key prey species (tree slugs Lehmannia marginata, in particular) in conjunction with microhabitat surveys will be conducted at two or more sites (likely to be Dendles wood and Bovey Valley woods) during spring and summer over three years. Beetles encountered will be captured and given a unique ID then released as part of a mark-release-recapture study to estimate population sizes and determine population structure (sex and age). Furthermore we plan to use radio-tracking to complement the survey and microhabitat work to assess movements of adult blue ground beetles in spring and summer as well as foraging ecology. In addition to fieldwork in spring and summer survey data will also be collected during the winter to determine microhabitat preferences and characteristics of overwintering sites used by adult Blue ground beetles.

The data collected will help inform vital decisions about how to manage existing woodland habitat within the NNRs including the extensiveness of grazing, the dead wood resource and any new sustainable management techniques by identifying key factors that determine Blue ground beetle habitat use and preferences, population characteristics and likely impediments to population expansion. It will help create a resilient Dartmoor landscape and establish what scale of woodland habitat restoration and new connections are needed to help build that 'resilience'.