Securing Biodiversity in Breckland - European Commission

Recommendation BTO be commissioned to analyse Atlas data, BBS data and other survey coverage fromBreckland, in relation to East Anglia and lowland England, to identify which species haveregionally or nationally important populations.Species historic to BrecklandWhere possible conservation priority species whose presence in Breckland is now only historic (i.e.locally extirpated or nationally extinct) were identified, using extinct statuses (Red Data BookExtinct), local knowledge, information from taxonomic experts and the Natural England publicationLost Life: England’s lost and threatened species (Brown et al. 2010).Data quality and resolutionA species record is defined as an observation of one species, in one place and at giventime.Mandatory and preferred fields for collated species records were:Identification to species levelIn addition to the 32,177 records from ADAS, a further 3525 records were received that were notidentified to species level. These records were obtained from a range of sources, including LocalRecords Centres, ISR and national recording schemes.Grid reference29,096 records (3.5%) were received from locations outside of the 23 Breckland 10 km grid squares.These included records supplied with incorrect grid references and valid records from outside theselected Breckland area.Most collated records had grid references resolved to a minimum of 1 km. However, 33,877 records(4.1%) were only resolved to 10 km. Species from these records were included in species andpriority lists, but were not considered when mapping to a 1 km resolution.151,138 observations, primarily of flowering plants, were recorded as tetrads. For mapping at a 1km resolution it was assumed that the observed species was found in all four 1 km squares thatmade up the tetrad, i.e. a single tetrad observation was converted to four single 1 km records. Thiswill over-represent the true distribution of some scarcer species and artificially smooth speciesdistributions. However, this is offset by the fact that many SSSI sites straddle a number of 1 kmsquares but species records are often placed on a hypothetical centre point.Observation dateThere were 904 records without an observation date or that had large date ranges that spannedeither side of the selected cut-off date of 1980 (see Data Mapping section for further details).These were included in species and priority lists but were removed prior to 1 km mapping ofpriorities.55