Download Habitat values for birds of revegetation in the NSW Southern

Habitat values for birds of revegetation in the
NSW Southern Tablelands
N. Taws, J. Reid, S. Streatfield
A study conducted by Greening Australia ACT & SE NSW Inc.
With help from the Canberra Ornithologists Group
And CSIRO Sustainable Ecosystems
INTRODUCTION
Throughout southern Australia our wildlife and ecosystems are in crisis. Wherever most of the
original vegetation cover has been removed for cropping, meat and wool production, the telltale
effects of erosion, soil, water and land degradation, and loss of biodiversity are evident.
Native birds have not been immune to these changes and populations of many species
dependent on natural habitats have been devastated. In many ways birds make an obvious and
ideal focus for environmental restoration initiatives because, and unlike many other plants and
animals, they are:
1. a well-researched group of organisms with a stable taxonomy;
2. often near the top of the food chain and so can both integrate across lower trophic levels
and serve as useful indicators for change and ecosystem health;
3. highly visible and popular among the general community due to their colour, songs and
active behaviour; and they are
4. easily studied, so scientists, non-scientists and community groups alike can make
important contributions to their study.
As environmental awareness has grown in recent times and partly in response to the emerging
perceptions of land degradation and biodiversity problems, there has been a steady increase in
the number of trees and shrubs planted in agricultural production landscapes over the last 15
years. There is now an increasing awareness of the need for revegetation efforts to become more
strategic and to be accountable because of the large investment of public funds in restoration
activities.
The current study follows recent Greening Australia research into the effectiveness of direct
seeding projects carried out to date in the NSW Southern Tablelands and adjacent SouthWestern Slopes in the greater Canberra region. By examining the establishment success and
growth rates of plants in relation to a number of technological and environmental factors, this
plant-oriented research has allowed Greening Australia to improve its direct seeding efforts in a
variety of ways. However, we still do not know what fauna is using this newly established habitat
and whether it is useful to wildlife, generally or at all.
In this study we examined the use that birds make of revegetated areas of land in the northern
ACT and adjacent parts of New South Wales, largely in the South-Western Slopes bioregion.
Specific aims of this study were to:
1. determine the level of habitat value that revegetation has for native birds in this region;
2. evaluate the effect of size, age, plant species composition, and landscape context of
revegetation efforts on their usefulness to birds;
3. draw conclusions about those facets of revegetation efforts that maximise their
contribution to providing useful bird habitat; and to
4. disseminate the results of the study to Landcare groups, councils, land managers and
other community organisations so as to improve the understanding, design and planning
of revegetation projects to benefit birds and, by implication, other local fauna.
METHODS
Multiple bird surveys, 416 in all, were conducted by members of the Canberra Ornithologists
Group at 132 sites, comprising 102 revegetation sites (62 direct seeded, 40 tubestock planted),
20 native vegetation control and 10 paddock control sites. These four categories constitute the
main treatment effect in this designed survey.
Revegetation sites varied in age from 14 months since establishment to 14 years. The 102
revegetation sites totalled just 268 ha in combined area within a region greater than 10,000 km2
in extent. The actual area of revegetation in the region is much greater than just indicated (albeit
still a tiny proportion of the total landscape), but the sites selected for study comprise a larger and
wider subset of all revegetation.
The bird counts conformed to the methods used for the National Atlas of Australian Birds (Barrett
1998), ie. they were each of 20 minutes duration, and covered a 2-ha area where possible except
that in narrow strips of revegetation the area surveyed was necessarily less than this. Only
species using the revegetation were recorded. The combined area of revegetated sites
systematically surveyed was 117 ha. A minimum set of one autumn-winter (= non-breeding) and
one spring-summer (breeding) census was carried out at all sites, in a 16 month period from
February 2000 to June 2001.
RESULTS
A total of 108 different bird species was recorded during the study, with 103 species using
revegetated areas. Five species, each recorded only once, were found only at natural or remnant
woodland (control) sites.
The most common species in revegetation were small insectivorous birds such as the Superb
Fairy Wren, Yellow-rumped Thornbill, Brown Thornbill, White-plumed Honeyeater, Grey Fantail
and Willy Wagtail. The 20 most commonly recorded species by reporting rate are listed in Table
1. The reporting rate is the percentage of the total number of surveys in which a species was
recorded.
Table 1The twenty most commonly recorded species in revegetation
Bird species
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Superb Fairy-wren
Yellow-rumped Thornbill
Crimson Rosella
Grey Fantail
Australian Magpie
Brown Thornbill
Yellow Thornbill
Rufous Whistler
Willie Wagtail
White-plumed Honeyeater
Grey Shrike-thrush
Eastern Rosella
Striated Pardalote
Silvereye
White-eared Honeyeater
Yellow-faced Honeyeater
Striated Thornbill
Buff-rumped Thornbill
Common Bronzewing
White-browed Scrubwren
Reporting rate
%
74
48
41
39
34
31
27
24
24
22
21
19
17
14
13
13
13
12
11
11
Twenty species were recorded using revegetation for breeding, even though specific searches for
evidence of breeding were not made.
Particularly exciting was the recording of 15 species of declining woodland birds. These were the
Painted Button-quail, Brown Treecreeper, Speckled Warbler, Southern Whiteface, Jacky Winter,
Red-capped Robin, Hooded Robin, Eastern Yellow Robin, Varied Sittella, Crested Shrike-tit,
Rufous Whistler, Restless Flycatcher, White-browed Babbler, Dusky Woodswallow and Diamond
Firetail.
Another pleasing result was the scarcity of undesirable birds such as the introduced pests House
Sparrow and Common Starling, and native increaser species like the Noisy Miner and Pied
Currawong - they were infrequently recorded in revegetation and were rarely abundant. Some of
the species only encountered in natural woodland remnants included Spotted Quail-thrush and
Little Friarbird.
We conclude that a wide range of native bush birds uses revegetation. The most important factors
influencing the number of species in any patch of revegetation were:







Age of the revegetation
Habitat complexity
Size of the site
Width of the site
Season
Distance to nearest bush remnant >5ha in size
Distance to nearest bush remnant >1000 ha in size
DISCUSSION
Remnant vegetation forms the critical backbone to any native vegetation strategy in the SE NSW
region. However existing remnants are frequently too small, isolated or degraded, and on their
own cannot sustain woodland bird populations in agricultural areas. Revegetation using native
local tree and shrub species has been shown to provide habitat for a significant proportion of the
woodland bird fauna of the region, including some of the “declining” species.
A number of bird species preferred or were restricted to remnant vegetation where they may be
reliant on resources such as hollows, logs, dead limbs, mature bark, abundant nectar and seeds.
However a suite of birds appeared to prefer the revegetation to remnants, possibly because of the
greater structural variety provided by shrub species and young trees or because of the greater
health and vigour of the young vegetation compared to some of the dieback-stricken remnants. A
range of mature, scenescing and regenerating vegetation is needed to provide different resources
for birds.
Options for improving revegetation efforts to benefit the range of woodland bird species include:
 fencing off existing remnants,
 increasing the size of remnants by planting around the outside,
 enhancing remnant structure by re-establishing understorey,
 using revegetation to create blocks of new vegetation or wide strips between existing patches.
 increasing the width of existing windbreaks or treelines,
 restoring ground structure by leaving branches, logs etc. where they fall, or by re-introducing
logs from areas where they may not be wanted.
REFERENCES
Barrett, G. (1998). Atlas of Australian Birds - notes on methodology for the new bird atlas. Birds
Australia, Melbourne.