Use by birds of riparian vegetation in an extensively fragmented landscape

Abstract

The bird communities of six riparian woodland sites are described and compared with those of eight terrestrial woodland sites in the Central Tablelands near Bathurst, New South Wales, Australia. Riparian woodland, where still present in the Central Tablelands, is dominated by either relatively narrow strips of Casuarina cunninghamiana along stream banks or the less restricted Angophora floribunda trees associated with Eucalyptus melliodora?E. blakelyi woodlands. Four of the riparian sites were located within cleared agricultural land and two were located within a relatively large nature reserve. Bird censuses along a strip transect were conducted twice per season from spring 1993 to summer 1996. The riparian woodland communities contained within the cleared landscape of the Bathurst basin were found to support a diverse avifauna, a mix of woodland-forest and species associated with agricultural landscapes. Extensive observations of individual birds at riparian sites indicate that the tree canopy is the most widely used microhabitat stratum. While native riparian woodlands are generally degraded, their connectivity and stabilizing function (actual or potential) identifies them as a critical landscape component in maintenance or restoration programmes. Hence it is suggested that riparian strips could form the basis for rehabilitation initiatives within this landscape. Fenced plantings of endemic tree species supplemented by native understorey species could be linked with existing vegetation to enhance landscape connectivity. It is crucial that landholders become aware of the importance of riparian vegetation for nature conservation and stream stabilization. Incentives should be provided to landholders to encourage these areas to be fenced from stock in order to protect them from further degradation in a significantly disturbed ecosystem.

Comparison of foraging behaviour of small, urban-sensitive insectivores in continuous woodland and woodland remnants in a suburban landscape

“…Loss of these plant species and their associated structural elements is likely to result in very significant changes in movement and foraging ability. Other studies similarly highlight the importance of canopy trees in the matrix (Munyenyembe et al 1989;Law et al 2000;Grabham and Klomp 2001) and in remnants with most bird species being observed in the tree canopy of riparian remnants (Fisher 1997), and along a regeneration gradient (Fisher 2001).…”

Woodland bird declines in the Murray–Darling Basin: are there links with floodplain change?

“…Floodplains and riparian zones are host to a wide range of woodland bird species that also occur in non-floodplain communities (Appendix 1; Fisher and Goldney 1997;Major et al 2001;Antos and Bennett 2005). These include resident, nomadic, and migratory groups, and many threatened and declining species (Reid and Fleming 1992;Reid 1999).…”

“…Woodland bird species richness, diversity, abundance, density, and breeding numbers have all been demonstrated to be significantly greater in floodplains and riparian zones compared with 'dry' non-floodplain and agricultural environments in Australia and the USA (Stauffer and Best 1980;Szaro and Jakle 1985;Best et al 1995;Fisher and Goldney 1997;Woinarski et al 2000). How different floodplain and riparian communities are from adjacent communities varies depending on scale, but in general differences in vegetation and bird communities between these environments are more distinct in rangelands and broadacre agricultural zones (Szaro and Jakle 1985;Knopf and Samson 1994;Saab 1999).…”

Avian assemblages in eucalypt forests, plantations and pastures in northern NSW, Australia

“…The juxtaposition of two dissimilar habitats increased habitat heterogeneity and provided resources for the most diverse assemblage of birds, a combination of forestand woodland-dependent species, and a larger number of opencountry foragers that have benefited from land-clearing (Fisher and Goldney, 1997). Riparian zones including gullies are characterised by higher moisture and nutrient levels than dryland, with increased structural complexity and elevated productivity, even in gullies without permanent water (Mac Nally et al, 2000), which in turn attracts species in greater densities (Bentley and Catterall, 1997;Woinarski et al, 2000;Palmer and Bennett, 2006).…”

“…The placement and management of these plantations will have significant effects on the biota within or around them. Moreover, remnants within plantations, such as riparian corridors which are known to support greater productivity and higher species richness and abundance (Bentley and Catterall, 1997;Fisher and Goldney, 1997), may provide linkages that assist dispersal and colonisation (Nasi et al, 2008), important functions given the highly fragmented nature of the reserve system. It is therefore important to assess the effectiveness of these remnants as linkages, when buffered by plantations.…”