THE INVASIVENESS OF CRATAEGUS MONOGYNA AND PRUNUS MAHALEB, AT ARMIDALE, NEW SOUTH WALES, AUSTRALIA By DAVID ANDREW BASS A Thesis submitted in fulfillment of the requirements for the degree of Doctor of Philosophy at the University of New England, Armidale. Department of Geography and Planning University of New England, Armidale New South Wales, Australia 30 March 1994 TABLE OF CONTENTS Page TITLE PAGE CONTENTS ii LIST OF TABLES vii LIST OF FIGURES xii LIST OF PLATES xv CERTIFICATE xvi ACKNOWLEDGEMENTS xvii ABSTRACT xx CHAPTER 1: INTRODUCTION 1 1.1 Biological invasions: introduction and literature 1 review. 1.1.1 Terminology of biological invasions 4 1.1.2 Characteristics of biological invasions with 9 reference to Australia 1.1.3 Ornamental plant invasions in Australia 18 1.1.4 Impacts of invasive plants 21 1.1.5 Focus of biological invasion research 23 1.1.6 Attributes of biological invaders 25 1.1.7 Attributes of invaded environments 27 1.1.8 Safe sites and biological invasions 29 1.2 The project 31 1.3 Study region 33 1.4 Study sites 35 1.4.1 Armidale State Forest (ASF) 35 1.4.2 Saleyards site 37 1.4.3 University of New England site (UNE) 38 ii CHAPTER 2: TAXONOMY, MORPHOLOGY, PHENOLOGY 40 AND REPRODUCTIVE ECOLOGY OF CRATAEGUS MONOGYNA AND PR UNUS MAHALEB 2.1 Crataegus monogyna 40 2.1.1 Uses of Crataegus monogyna 41 2.1.2 Taxonomy 42 2.1.3 Morphology 45 2.1.4 Phenology 46 2.1.5 Reproductive ecology 48 2.1.6 Distribution 48 2.2 Prunus mahaleb 51 2.2.1 Taxonomy 51 2.2.2 Morphology 52 2.2.3 Phenology 53 2.2.4 Reproductive ecology 54 2.2.5 Distribution 54 CHAPTER 3: HISTORY OF INTRODUCTION AND RATES 56 OF SPREAD OF CRATAEGUS MONOGYNA AND PRUNUS MAHALEB IN AUSTRALIA 3.1. The process of range expansion 56 3.1.1 Rates of spread 58 3.1.2 Determination of rates of spread 61 3.2 Crataegus monogyna in Australia 62 3.2.1 Tenterfield case study 66 3.3 Prunus mahaleb in Australia 78 3.4 Comparison of the rates of spread of Crataegus 82 monogyna and Prunus mahaleb in Australia. CHAPTER 4: DEMOGRAPHY OF CRATAEGUS MONOGYNA AND 85 PR UNUS MAHALEB 4.1 Introduction and literature review. 85 4.1.1 Population models 85 iii 4.1.2 Development of matrix models of population 88 growth 4.1.3 Modelling of long-lived perennials 91 4.1.4 Modelling of shrub populations 92 4.1.5 Construction of matrix models 94 4.1.6 Population dynamics of biological invaders 98 4.1.7 Determination of life-table data 101 4.1.8 Calculation of survival rates 101 4.1.9 Calculation of fecundity rates 102 4.1.10 Growth and transition rates 105 4.1.11 Determination of the latent root of 106 transition matrices 4.1.12 Census plots for Crataegus monogyna and 106 Prunus mahaleb 4.2 Crataegus monogyna demography 108 4.2.1 Flowering success of Crataegus monogyna 108 4.2.2 Fruit crop size of Crataegus monogyna 109 4.2.3 Estimates of density, standing crop and age 112 of seedlings 4.2.4 Fecundity of Crataegus monogyna 113 4.2.5 Survival and growth of established seedlings 113 4.2.6 Survival and growth of reproductive plants 114 4.2.7 Age structure of Crataegus monogyna 115 4.2.8 Causes of morbidity and mortality of Crataegus 116 monogyna 4.2.9 Life-tables and transition matrices for 119 Crataegus monogyna 4.3 Prunus mahaleb demography 123 4.3.1 Flowering success in Prunus mahaleb 123 4.3.2 Fruit crop size in Prunus mahaleb 124 4.3.3 Estimation of density, standing crop and age 126 of seedlings iv 4.3.4 Fecundity of Prunus mahaleb 128 4.3.5 Survival and growth of established seedlings 129 4.3.6 Survival and growth of reproductive plants 130 4.3.7 Age structure of Prunus mahaleb 130 4.3.8 Causes of mortality in Prunus mahaleb 132 4.3.9 Life-tables and transition matrices for Prunus 135 mahaleb 4.4 Discussion of the demographies of Crataegus monogyna 138 and Prunus mahaleb CHAPTER 5: DISPERSAL ECOLOGIES OF CRATAEGUS 143 MONOGYNA AND PR UNUS MAHALEB 5.1 Specialist and generalist dispersal systems 144 5.2 Biological invasions and seed dispersal 145 5.2.1 Interactions between introduced plants and 148 birds 5.3 Assessment of the dispersal ecologies of 149 Crataegus monogyna and Prunus mahaleb 5.3.1 The characteristics of Crataegus monogyna 150 and Prunus mahaleb fruit 5.4 Crataegus monogyna 153 5.4.1 Bird facilitated seed dispersal 153 5.4.2 Pied Currawong behaviour and seed dispersal 157 5.4.3 Pied Currawong autumn-winter diets in Armidale 163 5.4.4 Autumn-winter fruiting ornamental plants in 167 Armidale 5.4.5 Mammals 173 5.5 Prunus mahaleb 177 5.5.1 Bird facilitated seed dispersal 177 5.5.2 Mammal facilitated seed dispersal 189 5.6 Comparison of Crataegus monogyna and Prunus 191 mahaleb dispersal ecologies CHAPTER 6: DISCUSSION AND CONCLUSIONS 196 6.1 Overview of biological invasions 196 6.2 The specific outcomes of the project 197 6.3 Reasons for the differences in relative invasiveness 198 of Crataegus monogyna and Prunus mahaleb 6.3.1 Rate of spread of Crataegus monogyna and 199 Prunus mahaleb 6.3.2 Population growth of Crataegus monogyna and 200 Prunus mahaleb 6.3.3 Dispersal ecologies of Crataegus monogyna and 201 Prunus mahaleb 6.4 The relative importance of humans, plant 204 demography and seed dispersal in determining invasiveness of Crataegus monogyna and Prunus mahaleb 6.5 Management of invasions by fleshy fruiting 207 woody plants 6.5.1 Impact of fleshy fruiting woody plants 207 6.5.2 Weak points in the life histories of 208 Crataegus monogyna and Prunus mahaleb 6.5.3 Integrated approach to management of invasion 216 by ornamental plants 6.6 Recommendations for further research 218 6.7 Conclusion 219 REFERENCES 221 APPENDIX 1 254 APPENDIX 2 270 APPENDIX 3 272 vi LIST OF TABLES Page Table 1.1 Scale of biological invasions as regards the place of origin in a given invasion (from di Castri 1989). 11 Table 1.2. Scale of time of biological invasions with respect to the initial driving forces for a biological invasion (from di Castri 1989). 12 Table 1.3 The origins of the naturalized flora of South Australia at three different periods (from Kloot 1991). 16 Table 1.4. The manner of introduction of the naturalized species of South Australia. From Kloot (1991). 20 Table 1.5. Characteristics of the ideal invader (from Roy 1990). 26 Table 1.6 Yearly rainfall totals in millimetres between 1980 and 1991 for Armidale, New South Wales (from Burr 1988-1992). 34 Table 1.7 Mean daily minimum and maximum temperature (degrees Celsius) for Armidale (from Burr 1988-1992). 35 Table 2.1. Leaf morphology of C.monogyna in Australia and south-eastern England (after Byatt 1975). Sample sizes are shown in brackets. 45 Table 2.2. Prunus species naturalized or becoming naturalized in New South Wales (from Smith 1988). 52 Table 3.1 Estimated rates of spread of trees in the British Isles and mainland Europe (from Table 1 in Birks (1989)). 60 Table 3.2 Number, height, girth and ages of C.monogyna trees felled in 1990 at Tenterfield and calculated rates of spread away from the Poplar Gardens hedge with an establishment date between 1863 and 1890 (A in Fig. 3.3). See text for details. 78 Table 3.3 Ages of P.mahaleb trees felled from ASF in 1990. Rates of spread are calculated from the centre of the main infestation (point x in Fig. 3.4). 80 Table 4.1 Hypothetical life-table data grouped into age classes. 95 vii Table 4.2 Hypothetical transition matrix constructed from fecundity and survival values from table 4.1 95 Table 4.3. Population matrix divided into n classes 96 Table 4.4 The form of a size classified transition matrix for a population divided into five size classes (adapted from Caswell 1989). 96 Table 4.5 Proposed demographic differences between species with differing degrees of invasiveness. 100 Table 4.6. Fruit set rates for C.monogyna in ASF, Saleyards and Newholme sites for Spring 1988. Numbers in brackets refer to the number of branches in each size class surveyed. 109 Table 4.7 Regression equations for fruit crop estimates of C.monogyna at ASF in 1988 and 1989. Circumference = basal circumference (cm), height = height of tallest stem (cm), and basal area = basal cross--sectional area (cm 2 ), d.f. = degrees of freedom, and p = probability that S does not equal 0. 110 Table 4.8 Average fruit crops (1988 and 1989 combined) for C.monogyna at ASF based on height and basal circumference size classes. N = number of individual plants in each size class. Numbers are rounded to the nearest whole number. 111 Table 4.9 Average growth rates and proportion of individuals in each size class moving up a size class for C.monogyna at Armidale. s.d. = standard deviation rounded to nearest whole number for height classes and one decimal place for basal circumference classes. 114 Table 4.10 Initial size class distribution, growth rates, survival rates, transition probabilities and fecundity for C.monogyna near Armidale. Size classes based on height of tallest stem. 120 Table 4.11 Initial size class distribution, growth rates, survival rates, transition probabilities and fecundity for Crataegus monogyna at Armidale.