DOI: 10.5285/c8d0ac67-6d47-42b1-af29-2339be8a5d82
title: Bird and butterfly abundance from consistently surveyed agri-environmental monitoring transects at Hillesden, UK, 2006-2017

description: This dataset contains bird and butterfly abundance data from field-surveyed transects at Hillesden, UK (2006-2017). Over this time period, Hillesden hosted two five-year experimental manipulations of agri-environmental habitats, alongside monitoring of their impacts on biodiversity and agronomic indicators. This dataset contains data suitable for analysis of ten-year interannual population trends across both 5-year phases of experimental work at Hillesden, and subsequent comparison with equivalent trends derived from equivalent national recording schemes (Breeding Bird Survey (BBS) for birds, Wider Countryside Butterfly Monitoring Scheme (WCBMS) for butterflies). The data thus relate only to transects which were recorded consistently (nine for birds, seven for butterflies), and to species that were present on the majority of transects. This dataset thus represents a subset from the whole Hillesden biological survey dataset for these two groups, and contains maximum annual counts per transect, across monthly visits (April-August) within the permitted time frame from equivalent national recording schemes (BBS for birds, WCBMS for butterflies). Data were collected as part of a project led by the UK Centre for Ecology and Hydrology, funded by Defra, with analytical work funded by the Natural Environment Research Council (NERC) under research programme NE/N018125/1 ASSIST. ASSIST is an initiative jointly supported by NERC and the Biotechnology and Biological Sciences Research Council (BBSRC).
description: Birds were surveyed monthly in the breeding season (April-July) on ~1km transects. Butterfly surveys took place monthly May-August on a series of 2 x 50 m transects located within agri-environment schemes (AES) habitats, along with two-minute timed observations at either end of each transect. Bird and butterflies were identified, counted and recorded in the field by experienced surveyors, with locations mapped using unique transect ID (butterflies) or Ordnance Survey ∼1:2000 maps (birds). All data were then digitised by members of the survey team, allowing for error checking during and subsequent to data entry. For both groups, transects were filtered to identify those surveyed consistently across all experimental years (2006-2010 and 2012-2016 for birds, 2007-2010 and 2014-2017 for butterflies). Transects with no AES intervention and those which underwent changes in level of AES uptake were excluded. Species for analysis were selected on the basis of being present on the majority (>50%) of selected transects across all surveys. The data here pertain only to transects surveyed consistently over both phases of the experiment. Bird data were filtered to adults recorded within 10m of transects, excluding birds seen only in flight. Raw count data per visit were transformed to maximum counts of birds/butterflies per species per transect per year, in order to explore interannual trends and facilitate comparison with similar trends as calculated from national recording schemes.