Realm: Terrestrial
Climate: Temperate
Biome: Temperate broadleaf and mixed forests
Central latitude: 50.846300
Central longitude: 0.055200
Duration: 10 years, from 1978 to 1987

217 records

23 distinct species

Across the time series Pieris brassicae is the most frequently occurring species

Methods

From http://www.ukbms.org/Methods.aspx: The methodology and development of transect monitoring for butterflies has been reviewed in detail elsewhere (Pollard and Yates 1993). In brief a fixed-route walk (transect) is established at a site and butterflies are recorded along the route on a regular (weekly) basis under reasonable weather conditions for a number of years. Transect routes are chosen to sample evenly the habitat types and management activity on sites. Care is taken in choosing a transect route as it must then remain fixed to enable butterfly sightings to be compared from year to year. Transects are typically about 2-4km long taking between 45 minutes and two hours to walk and are divided into sections corresponding to different habitat or management units.Butterflies are recorded in a fixed width band (typically 5m wide) along the transect each week from the beginning of April until the end of September yielding ideally 26 counts per year. Transect walks are undertaken between 10.45am and 3.45pm and only when weather conditions are suitable for butterfly activity: dry conditions wind speed less than Beaufort scale 5 and temperature 13?C or greater if there is at least 60% sunshine or more than 17?C if overcast. Due to the vagaries of the British and Irish weather it is rare in practice to achieve a full set of 26 weekly counts. However a small number of missing values can be estimated using other counts during the season.Single species (as opposed to normal all species) transects have been increasingly established in recent years. Whilst such transects must follow the standard methodology and must record populations at least once a week throughout the flight period the focus on a single (or small number of) species reduces both the time required to walk each transect and more significantly the number of weekly counts. With many demands on the time of site management staff and volunteer recorders this reduced method has enabled population monitoring of particular threatened butterflies to be undertaken when otherwise it would not have been possible. By regularly recording a fixed route in standardised conditions the number of butterflies seen on a transect can be compared from year to year. Unit of abundance = IndCountInt, Unit of biomass = NA

Citation(s)

NERC (2010) “The Global Population Dynamics Database Version 2”. Centre for Population Biology, Imperial College. Available at: http://www.sw.ic.ac.uk/cpb/cpb/gpdd.html, accessed 2016.
Pollard, E. (1991) Monitoring butterfly numbers. In: F. B.Goldsmith (ed) Monitoring for Conservation and Ecology. Chapman and Hall.