Multi-Scale Associations between Vegetation Cover and Woodland Bird Communities across a Large Agricultural Region

Abstract

Improving biodiversity conservation in fragmented agricultural landscapes has become an important global issue. Vegetation at the patch and landscape-scale is important for species occupancy and diversity, yet few previous studies have explored multi-scale associations between vegetation and community assemblages. Here, we investigated how patch and landscape-scale vegetation cover structure woodland bird communities. We asked: (1) How is the bird community associated with the vegetation structure of woodland patches and the amount of vegetation cover in the surrounding landscape? (2) Do species of conservation concern respond to woodland vegetation structure and surrounding vegetation cover differently to other species in the community? And (3) Can the relationships between the bird community and the woodland vegetation structure and surrounding vegetation cover be explained by the ecological traits of the species comprising the bird community? We studied 103 woodland patches (0.5 - 53.8 ha) over two time periods across a large (6,800 km2) agricultural region in southeastern Australia. We found that both patch vegetation and surrounding woody vegetation cover were important for structuring the bird community, and that these relationships were consistent over time. In particular, the occurrence of mistletoe within the patches and high values of woody vegetation cover within 1,000 ha and 10,000 ha were important, especially for bird species of conservation concern. We found that the majority of these species displayed similar, positive responses to patch and landscape vegetation attributes. We also found that these relationships were related to the foraging and nesting traits of the bird community. Our findings suggest that management strategies to increase both remnant vegetation quality and the cover of surrounding woody vegetation in fragmented agricultural landscapes may lead to improved conservation of bird communities.

Bird diversity along a gradient of fragmented habitats of the Cerrado

“…However, in some cases, the bird communities may be primarily associated to local features and secondarily to features measured at a larger spatial scale (e.g., MacFaden and Capen 2002). They might also be affected by both, local and landscape variables (e.g., Cleary et al 2005, Ikin et al 2014, Leyequién et al 2010. Additionally, in other situations, the environmental variables are not important to bird communities structure.…”

Dynamic species co‐occurrence networks require dynamic biodiversity surrogates

“…Revegetation through either new plantings on cleared land or as enhancement plantings of existing remnants has occurred on 28 farms across a broad band over 6800 km 2 long since the 1990s, with the objective of restoring endangered Box Gum Grassy Woodland communities. Revegetation has resulted in increased woody vegetation cover and changes to key hollow and food resources (Ikin et al ). We are interested in finding the best surrogates for all bird species responding to revegetation over time.…”

“…Constraint (5) forces contributions of surrogate species i to every target species j to be null if restoring endangered Box Gum Grassy Woodland communities. Revegetation has resulted in increased woody vegetation cover and changes to key hollow and food resources (Ikin et al 2014). We are interested in finding the best surrogates for all bird species responding to revegetation over time.…”

The heterogeneity of wooded-agricultural landscape mosaics influences woodland bird community assemblages

“…During the 20 th Century, widespread landscape modification occurred throughout the wooded-agricultural environments of Europe, North America and Australia (Hendrickx et al 35 2007; Bonthoux et al 2012;Ikin et al 2014). Semi-natural landscape features including woodlands, hedgerows, grasslands and heathland were removed, fragmented or transformed to allow for larger agricultural fields, stands of non-native commercial coniferous woodland and urban expansion (Firbank et al 2007;Mason 2007).…”

“…This fundamentally altered the 'landscape heterogeneity' within wooded-agricultural environments, specifically the 40 landscape composition (number and proportion of different landcover types) and landscape configuration (spatial arrangement of different landcover types) (Heikkinen et al 2004;Devictor and Jiguet 2007;Barbaro et al 2007;Fahrig et al 2011). Such changes to these two complementary components of landscape heterogeneity have been linked to rapid declines in bird species diversity across a range of habitats and have had a strong impact on the 45 community composition of species that can be supported by a landscape (Bennett et al 2006;Haslem and Bennett 2008;Bonthoux et al 2012;Ikin et al 2014;Katayama et al 2014). As human demands on the land will continue to increase (Lawton et al 2010), there is a need to understand the complex interactions that exist between bird communities and different landscape factors (Mortelliti et al 2010) to manage the environment and apply conservation 50 measures effectively.…”