the effects of artificial watering points on the distribution and abundance of avifauna in an arid and

169 Pages·2002·4.87 MB·English

THE EFFECTS OF ARTIFICIAL WATERING POINTS ON THE
DISTRIBUTION AND ABUNDANCE OF AVIFAUNA IN AN ARID
AND SEMI-ARID MALLEE ENVIRONMENT
Rhidian Harrington
Submitted in total fulfilment of the requirements of the degree of Doctor of Philosophy
Department of Zoology
The University of Melbourne
April 2002
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ABSTRACT
The role of artificial watering points in the avifaunal dynamics of the semi-arid mallee woodlands of
southeast Australia was examined. Species richness and abundance were monitored throughout the
year at different distances from water to determine how birds were distributed around water points and
how this changed in relation to environmental factors such as climate. Vegetation attributes were also
measured to determine which factors explained patterns in the avifauna with distance from water, and
also to allow a description of the vegetation in relation to the water points. Water points were
monitored throughout the year to determine which species were utilising them, under which
environmental circumstances and for what purposes. Knowledge of the water utilisation behaviour of
individual bird species allowed some explanation of their distribution patterns, as well as an ability to
predict the likely effects of water point closure on those bird species. The closure of two water points
during the study allowed an assessment of the immediate effects of water point closure on avifauna.
The two broad vegetation associations on swales and dunes within the study area are described. Both
species richness and abundance of birds proved to be significantly higher in the swale vegetation, and
this was attributed to the greater structural and floristic diversity of the shrub layer within this
vegetation type. Vegetation around the water points was strongly influenced by distance from water,
with structural diversity and palatable plant species decreasing closer to water.
A total of 42 (37%) out of 113 bird species were observed drinking, although only 28 (25%) seemed to
require drinking water for their survival. Despite this, water-dependent species accounted for 75% of
the individuals observed. Granivorous species such as parrots and pigeons appeared to be the most
water-dependent, while some honeyeater species required drinking water during the summer months.
The presence of water had a major controlling influence on the abundance and distribution of numerous
bird species in this semi-arid mallee environment. Generally, water-dependent species were more
abundant closer to water; these were all common species of little conservation concern. The abundance
of water-dependent species decreased at distances beyond 12 km from water, although most species
were detected up to 20 km from water. Species richness was higher closer to water and this was due to
the abundance of water-dependent species there. A number of water-independent bird species were
more abundant closer to water, and these were small insectivorous species; their increased abundance is
attributed to significantly higher shrub height and cover closer to water. The majority of bird species
that decreased in abundance closer to water were ground-foraging species, and were positively
associated with particular low, dense shrub species that declined in abundance closer to water. Many
of these bird species such as the striated grasswren, southern scrub-robin and shy heathwren are of
conservation concern. Water point closure did not result in a significant change in bird abundances.
It was found that water points promote a loss of biodiversity, to the detriment of conservation
objectives, common water-dependent bird species benefiting at the expense of rarer water-independent
species. Vegetation and soil has been negatively impacted around water points, and this in turn has
negatively impacted a number of ground-foraging bird species. The management of artificial water
points within the arid zones of Australia is a critical issue, and unless practical solutions are found
avian biodiversity will continue to decline.
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DECLARATION
This is to certify that
(i) the thesis comprises only my original work towards the PhD,
(ii) due acknowledgement has been made in the text to all other material used,
(iii) the thesis is less than 100,000 words in length, exclusive of tables, maps, bibliographies and
appendices.
Rhidian Harrington
April 2002
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ACKNOWLEDGEMENTS
I would first like to thank my wife Sue who was an excellent and untiring field assistant. She spent
many, many hours in the field with me, often at ridiculous times of the day and through two
pregnancies, and for this I am eternally grateful.
Most of this study was conducted in Gluepot Reserve and Calperum Station (Bookmark Biosphere
Reserve), and I would like to thank the management of both for allowing me to conduct the research. In
particular I would like to thank Duncan Mackenzie, Mike and Wendy Mackintosh, and Beryl and John
English from Gluepot, and Mike Harper, Pam Parker, Kevin Smith and Sonia Dominelli from
Calperum. A very special thanks to Doug Holly for lots of help with field work in Calperum, but even
more so for lunchtime pancakes, homebrew, improving my knowledge of bird calls and a good yarn on
hot afternoons. Thanks also go out to all the Gluepot rangers who helped with fieldwork, particularly
Alex Bisgrove and Rob Sogdale for continuing the video surveillance in my absence. I would like to
give a very special thanks to my Dad who helped me with the sampling design and sampling of the
vegetation aspects of the study, and who also commented on my thesis. Thanks Mum for babysitting
and allowing uninterrupted periods for vegetation sampling; I know how much you hated it?! Thanks
also go to Michael Hyde for help with plant identification (or more appropriately, misidentification)
and for commenting on my vegetation chapter. I would particularly like to thank Rowan Clarke for
setting off the smoke alarm at 5:30 am each morning when ever he was present at Gluepot. Thanks also
to my father-in-law, John Wright who provided some non-biological perspectives on the thesis.
Some of this research was conducted at Murray Sunset National Park (MSNP) and I would like to
thank National Parks for allowing me to conduct the research. Many people at MSNP willingly
provided me with help and for this I am very grateful. Special thanks go to Russell Manning, Darryl
Murphy and Rob McGlashen.
Many people at the University of Melbourne helped in some way or another, and to those who did I a
very grateful. Particularly, I would like to thank Mick Keough, Dustin Marshall, Jan Carey and Ben
Miller for help with statistical procedures. Thanks also go to Damien Dowling for not attending a
single seminar I gave on my PhD. I am very grateful to the “soccer group”, who allowed me to vent the
frustrations of my write-up each Wednesday afternoon by kicking a football.
And finally, a very special thanks go to my two supervisors, David Morgan and David Baker-Gabb.
Thank you David B-G for highlighting the project in the first place and for your lightening evaluations
of my chapter drafts. And thank you David M for being an excellent supervisor, both academically and
personally. Your humor, knowledge (scientific and general) and anecdotes were greatly appreciated.
Finally, this research was funded by the Stuart Leslie Bird Research Fund, Holsworth Wildlife
Research Fund, the Norman Wettenhall Foundation and the Wildlife Conservation Fund (South
Australian National Parks and Wildlife). To these organisations and the individuals involved I am very
grateful.
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CONTENTS
Title Page .. .. .. .. .. .. .. .. .. i
Abstract .. .. .. .. .. .. .. .. .. iii
Declaration .. .. .. .. .. .. .. .. .. v
Acknowledgements .. .. .. .. .. .. .. .. vii
Table of Contents .. .. .. .. .. .. .. .. ix
List of Figures .. .. .. .. .. .. .. .. .. xii
List of Tables .. .. .. .. .. .. .. .. .. xiii
List of Plates .. .. .. .. .. .. .. .. .. xiv
1. INTRODUCTION AND OVERVIEW .. .. .. .. .. .. 1
1.1 Changes to wildlife around artificial watering points .. .. .. 1
1.1.1 The piosphere effect .. .. .. .. .. .. 1
1.1.2 Vegetation .. .. .. .. .. .. .. 2
1.1.3 Large herbivores .. .. .. .. .. .. 5
1.1.4 Avifauna .. .. .. .. .. .. .. 5
1.1.5 Predation risks .. .. .. .. .. .. 7
1.2 Water point placement .. .. .. .. .. .. .. 7
1.3 Water point utilisation by wildlife .. .. .. .. .. 8
1.4 Adaptations by avifauna to arid environments .. .. .. .. 9
1.4.1 Drinking patterns and diet .. .. .. .. .. 9
1.5 Aims of the present study .. .. .. .. .. .. 10
2. CHANGES IN VEGETATION AND SOIL CHARACTERISTICS AROUND ARTIFICIAL
WATER POINTS IN THE SEMI-ARID MALLEE OF SOUTHEAST AUSTRALIA .. 12
2.1 Introduction .. .. .. .. .. .. .. .. 12
2.2 Methods .. .. .. .. .. .. .. .. 14
2.2.1 Study Site .. .. .. .. .. .. .. 14
2.2.2 Sampling Design .. .. .. .. .. .. 16
2.2.3 Analytical Methods .. .. .. .. .. .. 17
2.3 Results .. .. .. .. .. .. .. .. 22
2.4 Discussion .. .. .. .. .. .. .. .. 33
2.4.1 Mallee Vegetation .. .. .. .. .. .. 33
2.4.2 Individual Species Responses .. .. .. .. .. 35
2.4.3 Conclusion .. .. .. .. .. .. .. 40
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3. THE DISTRIBUTION AND ABUNDANCE OF AVIFAUNA AROUND ARTIFICIAL
WATERING POINTS IN A SEMI-ARID MALLEE ENVIRONMENT .. .. 41
3.1 Introduction .. .. .. .. .. .. .. .. 41
3.2 Methods .. .. .. .. .. .. .. .. 43
3.2.1 Sampling Design .. .. .. .. .. .. 43
3.2.2 Sampling Procedure .. .. .. .. .. .. 44
3.2.3 Analytical Methods .. .. .. .. .. .. 46
3.3 Results .. .. .. .. .. .. .. .. 47
3.3.1 Changes in abundance .. .. .. .. .. 47
3.3.2 Changes in species richness .. .. .. .. .. 55
3.4 Discussion .. .. .. .. .. .. .. .. 57
4. PATTERNS OF WATER UTILISATION BY AVIFUANA IN A SEMI-ARID MALLEE
ENVIRONMENT .. .. .. .. .. .. .. .. 62
4.1 Introduction .. .. .. .. .. .. .. .. 62
4.2 Methods .. .. .. .. .. .. .. .. 63
4.2.1 Sampling Design .. .. .. .. .. .. 63
4.2.2 Sampling Procedure .. .. .. .. .. .. 65
4.2.3 Analytical Methods .. .. .. .. .. .. 65
4.3 Results .. .. .. .. .. .. .. .. 66
4.4 Discussion .. .. .. .. .. .. .. .. 75
5. THE RELATIONSHIP BETWEEN VEGETATION STRUCTURE AND FLORISTICS,
DISTANCE TO WATER AND AVIFAUNA IN A MALLEE SYSTEM .. .. 78
5.1 Introduction .. .. .. .. .. .. .. .. 78
5.2 Methods .. .. .. .. .. .. .. .. 78
5.2.1 Analytical Methods .. .. .. .. .. .. 78
5.3 Results .. .. .. .. .. .. .. .. 79
5.3.1 Associations between plant species and avifauna .. .. 79
5.3.2 Associations between vegetation structure and avifauna.. .. .. 84
5.4 Discussion .. .. .. .. .. .. .. .. 91
5.4.1 Differences between vegetation types .. .. .. .. 91
5.4.1 Differences with distance from water .. .. .. .. 93
5.4.3 Conclusion .. .. .. .. .. .. .. 95
6. THE IMMEDIATE EFFECTS OF WATER POINT CLOSURE ON AVIFAUNA IN A
MALLEE ENVIRONMENT .. .. .. .. .. .. .. 96
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