DOI: 10.5061/dryad.44j0zpch9
title: Birds and insects respond differently to combinations of semi-natural features in farm landscapes

description: Semi-natural features among farmland have a key role in maintaining
 wildlife in rural landscapes. Practical conservation requires knowledge of
 which combinations of features are of greatest value and whether this
 differs among faunal groups. We used a ‘landscape’ approach to investigate
 the relative importance to birds and insects (bees, flies, wasps) of
 combinations of three wooded features typical of farmland in south-eastern
 Australia: scattered trees, wooded roadsides and wooded streamside
 vegetation. We selected 44 landscapes (1 km diameter) representing four
 combinations: a) landscapes with all three features present, b) landscapes
 lacking scattered trees, c) lacking wooded roadsides, and d) lacking
 wooded streamsides. We surveyed birds and selected insects, and compared
 mean alpha (α, site), beta (β, between site) and gamma (γ, landscape)
 diversity for each taxon between landscape types; and gamma (γ) diversity
 of bird species displaying breeding activity. Mean α-diversity of birds
 was reduced in landscapes lacking wooded roadsides or streams, relative to
 those with all three wooded features; while species differentiation
 (β-diversity) increased in these landscapes. Loss of streamside vegetation
 had the greatest landscape-scale impact, reducing γ-diversity by ~33% for
 all land-birds and ~50% for woodland birds. Bird breeding activity
 declined by ~50% in landscapes lacking wooded streamsides. In contrast,
 insects showed little response, except bees for which mean α-diversity was
 greater in more-open landscapes lacking scattered trees or wooded
 roadsides, compared with those containing all wooded features. This did
 not lead to differences in landscape-level (γ) diversity. Synthesis and
 applications. Marked differences in how birds and insects respond to
 different combinations of semi-natural features mean that a ‘one size fits
 all’ approach to nature conservation is insufficient. Wooded features,
 especially streamside vegetation, are critical for maintaining diversity
 and breeding activity of woodland birds. In the absence of adequate
 knowledge of many insect groups in southern Australia, a prudent approach
 is to foster a diverse farmland mosaic comprising semi-natural habitats
 together with floristically rich, modified features that provide
 temporally dynamic resources. Small semi-natural features have
 disproportionate value for conservation, relative to their area, while
 also benefitting farm productivity and supporting ecosystem
 services. 
description: <strong>Point counts for birds</strong>
 Birds were surveyed at each
 site (n=12) in each landscape (n=44) using a 5-min point count. All birds
 detected visually or aurally within 20 m from the survey point were
 recorded. Surveys were conducted four times at each site; twice in spring
 2014, once during autumn/winter 2015 and once in spring 2015, by the same
 observer (MH). Each site was surveyed once in each of four time periods
 (early morning, mid-morning, mid-afternoon, late afternoon).
 <strong>Breeding records for
 birds</strong> We recorded breeding activity, both while
 undertaking surveys and while walking between points within the landscape.
 A final systematic search (2 hours) of the entire landscape was conducted
 in spring 2015. Each observation of a breeding activity was assigned to
 one of 13 behaviours, scored according to the strength of evidence to
 indicate breeding success.
 <strong>Sampling insects</strong>
 Three groups of insects (bees, flies and wasps) were sampled at
 each site (n=8) within each landscape (n=24). Vane traps (SpringStar Inc.,
 Woodinville, Washington) were hung from a tree branch or pole at ~2 m
 height. A single vane trap per site (blue traps only) was deployed for one
 week between October 2014 and January 2015 (austral spring and summer);
 and two vane traps per site (one blue, one yellow) again for one week
 between October and November 2015 (spring). No pheromones, liquids or
 killing agents were used in traps. Species-level identification of bees
 was conducted by MH and an expert taxonomist (see Hall, 2018). Flies and
 wasps were identified to the highest taxonomic level possible (see Hall
 & Reboud, 2019). Individuals not categorically identified to
 species were assigned a name based on the nearest congener (using the
 prefix cf before species name), or were considered
 morphospecies. All raw data are presented for each
 group in Excel spreadsheets (each group a separate tab).
description: Microsoft Excel or comparable software is required for opening
 the dataset.