COMPARATIVE SEED ECOLOGY OF NATIVE AND ALIEN PLANTS OF OPEN UPLANDS

Christopher Sean Blaney

A thesis submitted in conformity with the requirements for the degree of Master of Science Graduate Department of Botany University of Toronto

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The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or othewise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. auton sation. COMPARATNE SEED ECOLOGY OF NATIVE AND ALIEN PLANTS OF OPEN UPLANDS Master of Science 1999 Chnstopher Sean Blaney Department of Botany University of Toronto

Plant invaders may gain an advantage over natives because only enemy-free species are likely to invade (the predator filter hypothesis), or because invaders lose enemies while moving to a new area (the predator escape hypothesis). Working at the Joker's Hill Field Station, near Newmarket. Ontario, 1 bave combined site descriptions, surveys. and experiments to investigate the role of predaton and pathogens in seed ecology, and to understand their role in the establishment and spread of exotic species.

Results indicate that seeds of both natives and exotics suffered significant losses to above- ground predators and below-ground pathogens. Losses vaned among species and habitats; wrtlands had particularly high levels of fungal mortality. Aliens and natives did not consistently differ in their susceptibility to predators and pathogens, even when analyzed using methods that controlled for phylogenetic biases. These results suggest natural enemies of seeds do not as a general rule determine invasive ability. ACKNOWLEDGEMENTS Many people contributed to making my time as a Master's student enjoyable and rewarding, and 1 will do my best to recognize them al1 here. To those 1 have left out, my apologies, 1 am wnting this just hours before I have to submit, but to everyone my deepest thanks.

First and foremost 1 should recognize the efforts of my supervisor Professor Peter Kotanen, who was unceasingly attentive to my needs and generous with his tirne, advice and funding. 1 could not have completed this project without his help. He has gone well above the effort required of a supervisor and has taught me a great deal. 1 feel privileged to have worked with him as a student and as a friend. 1 have also benefitted greatly from the guidance and suggestions of al1 of the mernbers of n~ysupervisory cornmittees, which have included Profesors David Wedin, Spencer Barrett. Robert Jefferies and Gary Sprules. Aside from my committee, Professor Linda Kohn provided advice on a nurnber of issues related to soi1 fungi, and Professor Peter Bal1 was always ready to assist in the identification of tricky plant specimens. Interactions with many student colleagues have helped shape and sharpen rny academic skills as well providing happy diversions. Che Elkin. Marc Johnson, Luc Bussiere, Brendon Larson, Patrick Lorch, Andrea Case and rny fellow seed bank afficionado Esther Chang deserve special mention in this regard.

Jutta Stein, Greenhouse Technician at the University of Toronto at Mississauga deserves pürticular individual recognition. She went to great efforts to ensure my plants survived in the greenhouse. She always made space for my odd assortment of rather weedy specirs, even when they were spreading into ber pots. Her efforts not only allowed me to complete my thesis, but also enabled me to confidently have a life on weekends, knowing the crucial plants were well taken care of.

My work was aided substantially by the numerous field and laboratory assistants, paid and unpaid, who spent time in the Kotanen lab - Michelle Tseng, Sonya Carl, Arthur Poon, Joel Sotomayor, Sandra Benvenuto, Sheenagh Bell, Bill Kilburn, Carl Rothfels, Vijanti Ramlogan, Reagan Szabo, Marc Johnson and Uyen Dias. Not only did they offer able assistance on many difficult and repetitive tasks, they left me with many of my best, lasting memories of my time at Erindale.

At the Joker's Hill field site, property manager William Fox was always available when needed and was generous with the sites resources. The donors of the property, Murray and Marvelle Koffler should also be recognized. They have given the University of Toronto a unique gift, the value of which it is only just beginning to fully recognize. The Joker's Hill property is a rare jewel in the southem Ontario landscape and was a joy to work at.

I would also like to recognize my parents, who first inspired my love for the natural world and who have always been entirely supportive of my interests. Finally. to Becky Whittam, who has been my most important source of encouragement, sympathy. sustenance (literal and spiritual) and serene working conditions in the difficult tirnes leading to thesis completion. I thank you for your love and patience. TABLE OF CONTENTS Contents Page ABSTRACT ACKNOWLEDGEMENTS TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES CHAPTER 1 - General Introduction Overall Introduction Biological Invasions Seeds and Their Enemies Predator Escape and Predator Filter Hypotheses The importance of phylogeny Old Fields Objectives CHAPTER 2 - Vegetation of Joker's Hill Introduction Site overview Landfons and early human history of Joker's Hill Native plant communities: The historie setting Old fields: The study system Survey Methods The local species pool: Overall vascular plant species Species presence and abundance for main tkld sites Seed bank estimation for main field sites Results and Discussion Overall vascular plant species pool Rare native plant species Species presence and abundance at main field sites Seed bank estimation for main field sites Conclusions Contents - Pape CHAPTER 3 - Experimental Survey of Native and Alien Seed Mortality 36 Introduction 37 Methods 40 Study site 40 Experimental Species 4 1 Treatments 44 Soi1 srtrfnce seed predatinn experiment 44 Seed bank mortalin, experiment 45 Analysis 46 Resu lts 47 Soi1 surface seed predation experiment 47 Seed bank mortality experirnent 53 Discussion 72 Soi1 surface seed predation 72 Predator iden tity 72 Overd seed rernovcrl 72 Patterns in trentmerrt efects 74 Seed bank mortality experiment 75 Fwzg ideaddition 75 Invzrrebrate e.rclusion 76 Tenzporal pattern in seed recovery 77 Treatment efsecrs vs. seed size 78 Twonomic pattenz 78 Aliens vs. Natives 79 Contents Pape CHAPTER 4 - Comparative Experiments on Fungal and Habitat Effects on Seed Bank Mortality Introduction Methods Study site Experimental Species Treatments Analysis Results Overüll seed recovery Overall effects of fungicide addition Variation in seed recovery between species Variation in recovery by origin Discussion Does fungal mortality influence seed persistence in the soi1 seed bank? Do seed recovery and fungal mortality vas, between wetland and upland meadows? Does fungal mortality Vary betwren closely related natives and alirns?

CHAPTER 5 - General Conclusions Achievernent of thesis objectives a) to provide background information on the site and biological setting of the experiments b) to determine whether seeds suffer significant losses to predators before incorporation into the seed bank

C) to deterrnine whether seeds suffer significant losses to seed predators and uathooens in the seed bank Contents Page CHAPTER 5 (cont'd) d) to discover whether seed losses to naturd enemies differ among species 104 e) to determine whether seed losses to natural enemies differ between habitats 1O4 f) to determine whether seeds of native and alien species differ in their susceptibility to natural enemies 105 g) to determine whether differences in seed losses between natives and aliens occur independent of their phylogenetic relationship 105 Limitations of the work 1 O5 General Conclusions 1 O6

LITERATURE CITED 1 O7

APPENDIX 1 - Vascular Plants of Joker's Hill 1 APPENDIX II - Rare Native Vascular Plants of Joker's Hill XX APPENDIX III - Birds of Joker's Hill XXI 1 APPENDIX IV - Mammals of Joker's Hill XXVI APPENDIX V - Reptiles and Amphibians of Joker's Hill XXVII

vii LIST OF TABLES

Table 2.1. Species present at Dead Man's Curve and Wet Meadow field sites, within the area of the Kotanen plots.

Table 2.2. Abundance of species found in intensively sampled plots at Dead Man's Curve field site.

Table 2.3. Abundance of species found in intensively sampled plots at Wet Meadow field site.

Table 2.4. Geninable seed banks (mean seedslm22 SEM) from top and bottoni halves of cores from Dead Man's Curve and Wet Meadow field sites, fall 1997 and spring 1998 trials.

Table 2.5. Garminable seed bank (mean seeds/m2 to IO cm depth t SEM) at the Dead Man's Curve field site, fdl 1997 and spnng 1998. Table 2.6. Germinable seed bank (mean serdslrn2 to IO cm depth - SEM) at the Wet Meadow field site, fdl 1997 and spring 1998.

Table 3.1. Experimental species for seed bank mortrility and soi1 surface seed predation experiments, indicating presence on Joker's Hill research station property, and at the Dead Man's Curve research site.

Table 3.2. Resuks of seed predation experiment: Mean proportional seed recovery +. SEM.

Table 3.3. Results of 3-factor randomized block factorial ANOVAs on overall, nativeand alien data from seed predation experiment.

Table 3.3. Seed predation experiment; vertebrate exclosure and invertebrrite e~closureeffects on seed recovery by species, with seed weights.

viii Table 3.5. Proportions of total seeds in each trial recovered as seedlings in the field and by germination in the greenhouse in the seed bank experiment.

Table 3.6. Results of 3-factor randomized block factorial ANOVAs on overall data (native + alien), native data and alien data for 4 month trial of the seed bank experiment.

Table 3.7. Resul ts of 3-factor randomized block factorial ANOVAs on overall data (native + alien), native data and alien data for the 1 i month trial of the seed bank experiment.

Table 3.8. Results of 3-factor randomized block factorial ANOVAs on overdl data (native + alien), native data and alien data for the 14 month trial of the of seed bank experiment.

Table 3.9. Results of four month trial of seed bank expenment: Mean percentage seed recovery corrected for soil losses, by treatment and species, A SEM.

Table 3.10. Results of l 1 month trial of seed bank experiment: Meaii percentage seed recovery corrected for soil losses, by treatment and species, ISEM.

Table 3.1 1. Results of 16 month trial of seed bank expenment: Mean percentage seed recovery corrected for soi1 losses, by treatment and species, ISEM.

Table 4.1. Experimental species for the seed bank - habitat expriment, indicating presence on Joker's Hill research station property.

Table 4.2. Results of 2-factor randomized block factorial ANOVAs (fungicide treatment x species) on recovery data for the upland and wetland trials of the seed bank - habitat experiment.

Table 4.3. Mean * SEM percentage seed recovery, by treatment and species: Seed bank - habitat experiment, upland trial.

Table 4.4. Mean t SEM percentage seed recovery, by treatment and species: Seed bank - habitat experiment, wetfand trial. Table 4.5. Results of 3-factor randomized block factorial ANOVA (fungicide treatment x origin x genus) on the recovery data for the upland trial of the seed bank - habitat expriment. 94

Tabk 4.6. Results of PIC ANOVAs (fungicide treatment x genus) on native vs. dien contnst data for the upland and wetland trials of the seed bank - habitat expriment. LIST OF FIGUWS Fipure Ti tle Pape Figure 2.1 Map of Joker's Hill property . 14

Figure 3.1. Ovenll results of the above-ground seed predation experiment: Proportion of seed recovered in controls and predator exclusion treatments.

Figure 3.2. Results of the four month trial of the seed bank experirnent. by mcthod of recovery (germination in field and germination in greenhouse). Proportion of seeds recovered are corrected for physical losses. Results are given for all species, for native species only and for aiien species only. 63

Figure 3.3. Results of the 1 1 month trial of the seed bank experiment, by inethod of recovery (germination in field and germination in greenhouse). Proportion of seeds recovered are corrected for physical losses. Results are given for al1 species, for native species only and for alien species only. 64

Figure 3.4. Results of the 16 month trial of the seed bank experirnent, by method of recovery (germination in field and germination in greenhouse). Proportion of seeds recovered are corrected for physical losses. Results arc given for al1 species, for native species only and for alien species only.

Figure 4.1. Results of seed bank - habitat experiment; proportion of seed recovered in upland and weiland habitats, for native and alien species, under control and fungicide addition treatrnents. CHAPTER ONE

GENERAL INTRODUCTION CHAPTER 1 : GENERAL INTRODUCTION

Overall introduction As the primary means of reproduction and dispersal for most plants, seeds are a fundamental pan of most plants' life cycles. A vast literature exists covenng seed biology, both in ecology and in a wide range of other disciplines. Nonetheless, some aspects of the field ecology of seeds are not well understood. Most seeds are small and their fates are hard to follow once they leave the parent plant. This is unfonunate since it can leave a vast proportion of a species' total mortality as an unknown. With this gap in the understanding of plant population demography, questions about the extent to which seed pathogens and predators structure plant communities and the utility of seed ecology in providing useful predictors of plant invasion are difficult to answer

The general goal of this thesis is to investigate the role of natural predators and pathogens in sced ecology, and in particular to understand their role in the establishment and spread of exotic species. In the pages ahead, these themes will be more fully developed

Biological invasions Exotic, or alien species are those species which have arrived at an area outside their natural range with deliberate or unintentiond human assistance (Elton 1958. Baker 1974, Groves and Burdon 1986, Mooney and Drake 1986, Drake et al. 1989, Py Sek et al. 1995, Mack 1996, Williamson 1996). Today few, if any, regions are free of alien species, and the frequency of biological invasions continues to increase with human alteration of natural ecosysterns and the increasing global interdependence of economies (Dicastri 1989, Viiousek et al. 1996). Vascular plant invaders are especially numerous (Pyiek et al. 1995, Cronk and Fuller 1995). For examplc. Heywood ( 1989) estimates the introduced vascular flora of Australia at 1500 - 2000 species. Kent ( 1992) lists 1 189 established alien species in the British Isles and Scoggan ( 1978) lists 88 1 alien species in Canada. The first alien plants reached North America with the earliest European settlement. Whitney (1994) cites early records showing that at Ieast 40 species of European weeds were established around settlements in Massachusetts in 1672, with numbers rising to 140 species in the Boston area by 1840. Today, alien species generally make up 25 to 35% of local floras in northeastern North Amerka (Whitney 1994), with higher percentages in heavily urbanized areas. The proportion of aliens continues to increase as new invaders arrive. Additions to the Ontario weed fiora are made every year (e.g., Blaney, Oldham and Reznicek 1997, Oldham 1998, 1999) and the rate of invasion may be increasing, as has been suggested for Illinois (Henry and Scott 198 1). lnvading species can profoundly alter ecosystem processes, structure and composition, posing CHAPTER 1 : GENERAL lNTRODUCTlON

serious concerns for the conservation of native species and often costing millions of dollars in remediation and control efforts (e.g., Heyligers 1985, Vitousek 1986, Vitousek et al. 1987, Braithwaite et al. 1989, Hughes et al. 1991, Mack and D'Antonio 1998). Although consequrnces of some biological invasions can be ecologically devastating. most arriving plant invaders never become established, or have no noticeable impact if they do (Williarnson and Fitter 1996a, 1996b). The potential for alien species to have major negative impacts and the substantial variation in invasiveness between even closely related species has stimulated a grcat deal of interest in the liteature. Many researchers since the 1950s have attempted to develop generül rules to help predict which species will make successful invaders (e.g., Elton 19%. Baker 1974, Groves and Burdon 1986, Mooney and Drrike 1986, Drake et al. 1989, Pimm 1989, Mack 1996, Williamson and Fitter 1996a, 1996b) and which communities are susceptible to invasion (e.g., Crawley 1987, Mack 1989, Rejminek 1989, Groves and Dicastri 199 1). These efforts have produced few, if any, rules with strong predictive value (Perrins et al. 1992. Lodge 1993, Mack 1996). One reason for this lack of success is the fact that aliens are extremrly diverse. Rules demonstrated to apply to one group (Le. the genus Pinus, Rejminek 1995) may fail when applied to other groups. Another reason for the difficulty in developing a predictive ecology of invasions may be the methods used to derive the predictions. Early efforts tended to involve single-species case studies or generalization based on analyses of successful invasions. without much observation of unsuccessful invasions, or resistant communities (Burke and Grime 1996) or studies of mutiple species. Some recent studies have used statistical analyses of large species pools to correlate plant traits with invasion across taxa (e.g., Mazur 1989, Scott and Panetta

1993, Crawley, Harvey and Purvis 1996, Kotanen, Bergelson and Hazlett 1998) but there ;ire still very few explicit, experimental tests of hypothesized rules about plant invaders. As Burke and Grime (1996) state, "There is now an urgent need for the initiation of field experiments that test some of the more important invasibility hypotheses that have been gencnted from the study of past case histones."

Seeds and their enemies Many species suffer the majority of their mortality at the seed stage (Roberts and Feast 1972, Harper 1977, Cook 1980, Cavers 1983). Seed predation has been studied extensively and is well surnrnarized in several reviews (Thompson 1987. Louda 1989b, Crawley 1992; Chambers and MacMahon 1994). Patterns of seed mortality may be important in deciding the distribution and fate of plant populations (Janzen 1972, Grubb et al. 1982, Howe et al. 1985). and the results of interactions between competing species can be decided by the relative mortality patterns of their seeds (V.K. Brown et ai. 1987. Louda 1989a). Crawley ( 1992) suggests that pre-dispersal and post-dispersal seed predation have a number of contrasting features. The predator taxa involved overlap. but host-specific insects are often important in pre-dispersal predation, while post- dispersa1 seed predators are mostly genenlists with respect to the seed species consumed. Studies of post dispersal predation in North American and Old World deserts have shown that their comrnunities of obligate granivore taxa, especially rodents and ants, produce intense predation with very strong cornmunity level effects (Reichman 1979. Abramsky 1983. Parmenter et al. 1984, Heske, Brown and Guo 1993). Tropical forests have also been well studied. especially with reference to seed predation risk relative to dispersal distance. Seed beetles (Bruchidae; Janzen 1972, 1975) and seed bugs (Lygaeidae; Howe et al. 1985) have been shown to severely restrict seed survival near the parent tree in tropical forests. In old fields in northea~emNorth America. post dispersal seed predation is generally less intense. The ants, rodents and birds which eat seeds are mostly facultative granivores which may switch to other food sources in the summer (Mittelbach and Gross 1984. and references therein). Post dispersal seed predation may still exert an influence on species' distribution and abundance in old fields (Reader 1993, Hulme 1994). In old fields vertebrates are generally more important predators than anis (Mittelbach and Gross 1984, Hulme 1994), at least for the larger seeds (Thompson 1987). Factors such as predator identity, seed abundance and dispersion and nutritional value cm al1 affect the cntical size below which seed predation by birds and mammals is reduced. Studies by Kelrick et al. ( 1986), Mittelbach and Gross (1984) and Reader ( 1993), however, suggest that seeds below 1 to 3 mg tend to escape predation by a wide range of vertebrates.

Those seeds not consumed by predators immediately after dispersal become part of the soi1 seed bank. Seed banks Vary in size between habitats (Roberts 198 1, Thompson 1987, Leck et cd. 1989. Baskin and Baskin 1998), with differences retlective of patterns of addition and loss from the seed bank. Input to the seed bank is only through seed rain, but the magnitude of seed rain alone does not necessarily retlect the size of the persistent seed bank in a comrnunity. Species composition is an important determinant of a community's seed bank size because seed min and the intrinsic capacity for long term persistence both vary widely across species (Crawley 1997, Baskin and Bmkin 1998). The value of long terni seed banking for a plant species varies with its life history and the regularity of opportunities for reproduction. Thus longer lived species with relatively constant opponunity for recruitment are less likely to produce large, long term seed banks than are short Iived plants in habitats which experience wide tluctuations in abiotic conditions, though exceptions to these generalities are also numerous (Baskin and Baskin 1998).

In addition to the intrinsic seed longevity of a cornmunity's species, extrinsic factors will influence seed bank composition and abundance. primarily by affecting the rate of seed loss from the seed bank. tosses from the seed bank occur in one of two main ways. Seeds rnay be killed CHAPTF.R 1 : GENERAI. WTRODUCTION

by predators, pathogens or chernical deterioration or they rnay germinate. These factors are in tum controlled by predator and pathogen abundance and by abiotic conditions, such as rnoisture and temperature regime (Cavers 1983, Chambers and MacMahon 1994). Seed distribution in the soil column and germination are also strongly influenced by soil disturbance in many communities (Leck et al. 1989). Thus seed banks in communities with similar species composition cm still Vary substantially if germination or seed mortality differs, as with the increased fungal mortality associated with moist microclimates in tropical forests (Augspurgrr and Kelly 1984).

In addition to the intrinsic seed longevity of a community's species, extrinsic factors will influence seed bank composition and abundance, primdy by affecting the rate of seed loss from the seed bank. Losses from the seed bank occur in one of two main ways. Seeds rnay be killed by predators, pathogens or chernical deterioration or they rnay germinate. These factors are in tum controlled by predator and pathogen abundance and by abiotic conditions, such as moisture and temperature regime (Cavers 1983, Chambers and MacMahon 1994). Seed distribution in the soil column and germination are also strongly influenced by soil disturbance in many communities (Leck er al. 1989). Thus seed banks in cornmunities with similar species composition can still Vary substantially if germination or seed mortality differs, as with the increased fungül mortality associated with moist microclimates in tropical forests (Augspurger and Kelly 1984).

For species with long term seed banks, this stage may actually be where most mortality occurs (Cavers 1983, Chambers and MacMahon 1994). Despite the potential importance of seed bank mortality (Cavers 1983, Cavers and Benoit 1989, Crawley 1992, Chambers and MacMahon 1994, Baskin and Baskin 1998) there is strikingly little experimental work examining its causes in natural systems. Pathogens are often suggested to be important and there are a number of reasons to believe that fungi may be an important source of mortality for seeds in soil seed banks in natural habitats. Soi1 fungi are ubiquitous, abundant and include many important decomposers with the ability to secrete extracellular cellulase and proteolytic enzymes (Crist and Friese 1993). Many fungal plant pathogens, including some which can have significant community level effects (Kliejunas and Ko 1976, von Broembsen and Kruger 1984. Augspurger and Kelly 1984) are also soil borne (Garrett 1970). Additionally, the importance of fungicidal seed coatings in agriculture (Taylor and Harman 1990), the fungal scarification of some seeds with hard seed coats (Gogue and Emino 1979, van Leeuwen 1981, Guttridge et al. 1984) and the presence of fungal-inhibiting compounds in seed coats (references for 8 species given in Baskin and Baskin 1998) dl suggest that fungi are likely to be an important source of seed mortaiity in soil. A few CHAPTER 1 : GE- PJIXODUCTION studies in the ecological literature do provide evidence of fungal degradation of seeds in soil. Crist and Friese (1993) found that proportions of decomposed seeds among 5 shrub-steppe species ranged from <5% to 93.5% over 10 rnonths. They implicated fungi as a causal agent by isolating 7 fungal species from the retrieved seeds. Lonsdale (1993) specifically demonstrated increased seed survival after experimentally reducing soil fungi in a natural cornmunity. finding that fungicide addition resulted in a 10-16% increase in seed survival for Mimosa pigra in northem Australia.

Although the ecological literature is rather deficient in its examination of fungus-induced seed rnortality, the plant pathological literature, especially that which relates to agriculture. contains an abundance of information on fungi isolated from particular seeds (e.g. Neergaard 1977, Ginns 1986) and on the effects of anti-fungal treatments on crop germination, survival and yield (Torgeson 1969, Sharvelle 1979, Sinha et al. 1988).

Damping off diseases caused by fungi are known to be a major source of mortality at the seed and early seedling stages in crops with some evidence that this may be a general phenornenon in natural habitats as well. Damping off disease organisims are extremely common and widespread in zones of moist tropical and temperate climate worldwide and have major agricultural and ecological impacts in a range of habitats (Kliejunas and Ko 1976, von Broembsen and Kruger 1984. Augspurger and Kelly 1984, Manners 1993, Blakeman and Williamson 1994. Lucas 1994).

Broadly defined, dûrnping off disease can refer to both seed and stem rots of plants at al1 life stages (Agrios 1978). The stricter definition in more common usage is, "...destruction of seedlings near the soil line, resulting in the seedlings falling over on the ground" (Agrios 1978). The relatively rapid deterioration and disappearance of seeds and seedlings affected by damping off means that specific, focussed effort at disease detection may be required in studies on fungal seed and seedling mortality. The fungal species involved in damping off are primarily generalists with a very broad range of host plants recorded (Manners 1993, Blakeman and Williamson 1994, Lucas 1998). Ginns (1986) reviews host records of plant pathogenic fungi in Canada, listing damping off organisms associated with a number of the study species of Chapters 3 and 4.

The pathogens most commonly associated with seed rots and other damping off diseases are summarized in Agrios (1978). He lists members of Oomycota (Pythium spp., Phytopthora spp.), CHAPfER 1 : GENEW INTRODUCTION

Basidiomycota (Rhizoctonia solani and other Rhizoctonia) and lmperfect members of the Ascomycota (Botrytis spp.). Often, the same fungal genera or species associated with seed rots are known to cause a diverse range of other plant pathologies of roots and above ground plant parts (Agrios 1978, Manners 1993, Blakeman and Williamson 1994, Lucas 1998). Moisture level in the soi1 is one of the major factors influencing which of the above pathogens are likely to be prevalent. The Oomycota, now considered to be only distantly related to the tue fungi, have flagellated zoospores, making them more water dependent than tme fungi (Kendrick 1992). They are likely to be the predominant seed pathogens in very moist soils (L. Kohn, pers. comm.).

Predator escape and predator filter hypotheses The crucial role seeds play in reproduction and dispersal for most plants means that understanding seed ecology is especially important in developing an understünding of the füctors that control the success of invading species. Significant differences in seed weight and persistence between invasive and non-invasive or native and non-native species suggest that seed biology rnay be useful as a predictor of invasiveness, both within narrow taxonornic groups (Rejminek 1995) and across entire floras (Mazur 1989, Crawley. Harvey and Purvis 1996). Crawley, Harvey and Purvis (1996) found that British aliens were more likely than natives to have long term seed banks and Rees and Long (1992) found that 75% of species undergoing range expansion in Bntain (both native and alien, but skewed towards aliens) produced long tem seed banks. Sirnilarly, almost al1 of the world's worst weeds listed in Holm et al. ( 1977) produce substantial seed banks. The link between seed banking and invasions is a logical one. Seed banks are known to be important in buffering against poor reproductive years and the stochastic events which can wipe out small populations. Most invaders would repeatedly face these barriers during establishment (Baker 1974, Grime 1979, Keddy and Reznicek 1982, Rees and Long 1992) and spread (Barrett and Richardson 1986, Barrett and Husband 1990). The presence of a long term seed bank is also suggested to be one of the most important factors limiting the effectiveness of seed predators in biological weed control (Holloway 1964, Dahlsten 1986).

One frequently proposed hypothesis is that invaders succeed because they experience lower levels of pathogen and predator attack than do natives. There are two distinct reasons that aliens rnight enjoy lower rates of seed loss than natives. Both of these hypotheses argue that a low Pest load is important to invasion. The distinction lies in the mechanism causing this low load. First, invaders may lose their natural enernies when they are transponed to a new area (the predator escape hypothesis: Elton 1958, Crawley 1986). Second, perhaps species with intrinsically low rates of seed predation make better invaders because they are less likely to be eliminated by natural enemies in their new habitat (the predator filter hypothesis). These two hypotheses are CHAPTER 1 : GENERAI, INTRODUCTION

difficult to distinguish, but the escape hypothesis predicts that invaders should have lower Pest loads in new habitats, while the filter hypothesis predicts that pest loads are equally low in both original and new areas. As well, the escape hypothesis refen primarily to the loss of species- specific enemies. while the filter hypothesis is more likely to apply to generalist enemies.

There is some supporting evidence for both hypotheses. The strong host specificity of many plant pathogens and predators (Harper 1977, Dinoor and Eshed 1984. Crawley 1992) suggests the potentid importance of predator escape for plants arriving in new regions. Most alien plants. excepting ornamental species. are probably introduced as seed, rneaning that that certain types of predators and pathogens are unlikely to have arrived with them. It should be noted, however, that fungal and other pathogens are often transported on seeds (Neergaard 1977. Agarwal and Sinclair 1997), so invaders may be less likely to escape from specialist seed-borne pathogens. The concept of predator escape is fundamental to biological control effons. which often attempt to replace "lost" predators. Certain spectacularly successful biological control efforts. as with Opiimia species in Australia (Mann 1970) and South Africa (Zimmermann et al. 1986), and Hypericum perforarurn in California (Huffaker and Kennett 1959) strongly suggest it to be true for some plant invaders. However, the fact that rnost biological control effons fail (Crawley 1986) suggests that these examples may not be typical. Further evidence links predator escape at the seed stage to invasiveness. Some invaders have been shown to develop larger seed banks in new regions than in their native habitats. Lonsdale and Segura (1987) found that seed banks of ~Minlosapigra were approximately 100 times larger in Australia than in its native range in Mexico. Research in coastal shrublands in Mediterranean climate zones of Australia and South Africa (Weiss and Milton 1984) has shown that seed banks of the reciprocally invasive Acacia longiJoliu (native to Australia) and Chrysanrhemoides rnonilifera (native to South Africa) were increased 44 and 13 16 times in new regions.

There has been less investigation of the idea that species subjected to low Pest loads make better invaders; however, the evidence that sorne cornrnunities resist invasion (e.g., Pimm 199 l), points to the possibility that the predator filter hypothesis may apply in sorne cases. Additionally, correlations between seed size and predation rates, and between seed size and invasiveness (Crawley, Harvey and Pagel 1996) suggest that native and alien species may have intrinsically different rates of generalist predation, as predicted by the filter hypothesis.

The importance of phylogeny Native and alien species within the floras of particular areas invariably have different taxonornic distributions (Heywood 1989, Crawley, Harvey and Pumis 1996). This can lead to problems of ÇHAPTELGENERAL INTRODUCTION

interpretation when considering differences between natives and aliens using correlation across numerous species. Analyses of phylogenetically independent contrasts (PICs) can help to clarify the results obtained by correlational methods. PICs can detect relatively subtle native-alien differences which othenvise might be lost in the "noise" created by the inclusion of very different species in the same dataset. Second. PICs can help detect whether or not a significant result is an artefact produced by phylogenetic confounding. as in the following example.

Suppose we were trying to determine the importance of disease resistance for alien species and we fi nd that the average alien species has signi ficantl y greater resistance than the average native. This resu1t suggests that disease-resistant species are more frequent invaders. This is an important conclusion, but this TIP approach (Le., no phylogenetic correction) cannot eliminate the possibility t hat di fferences in disease resistance between natives and aliens are merel y characteristics of the phylogenetic groups to which they predominantly belong, and are unrelated to the characters which actually lead to invasiveness. The effects of origin are confounded with al1 other traits which are conservative with respect to phylogeny (Felsenstein 1985; Harvey and Pagel 199 1; Gittleman and Luh 1992; Miles and Dunham 1993). The solution to these problems is to adopt a PIC (phylogenetically independent contrast) approach (Felsenstein 1985; Harvey and Pagel 1991; Gittleman and Luh 1992; Miles and Dunham 1993). PICs control for phylogenetic correlation by contrasting native and alien clades which are more closely related to each other than to any other clades in the species set. They describe what aliens do, relative to othenvise similÿr relatives. In doing this. they reduce both irrelevent phylogenetic noise and the risk that any effects detected are actually spurious correlations. If the PIC approach were used and it was still found that aliens had greater disease resistance than natives, the result would be unlikeiy to be a consequence of some confounding trait shared by related invaders but unrelated to invasiveness. Sorne studies already have applied the PIC approach to cornparisons of native and alien floras (Crawley, Harvey and Purvis 1996, Kotanen, Bergelson and Hazlett 1998).

Old fields Southem Ontario, like most of eastem Nonh America, has been highly altered since seulement. The forest dominated landscape has been greatly reduced and fragmented south of the Canadian Shield to one of forest patches amid largely open active farmland, urban areas and old fields. Old fields, the system in which this thesis was conducted, are open areas which have been cleared by humans, usually for agriculture, and subsequently abandoned to natural successional processes. These areas differ substantially in species composition from natural upland openings in that they contain a mix of alien and native species. In southem Ontario, they also have become a much CHAPTER 1 : GENERAL INTRODUCTION more prominent feature of the landscape than were natural openings in pre-European times (Riley and Mohr 1994).

The fact that old fields are not a natural feature of the landscape begs the questions "Whcre do old field species corne from?". Some of the alien species, including many legumes and the grasses such as Pua pratensis and Brornus iriemis which are often community dominants, were introduced deliberately to NA as hay and forage species for livestock. Many other alien species have spread from plants originally grown for medicinal or food use by early settlers (Whitney 1994). A great many alien plants were also introduced accidentally; in ship ballast, livestock fodder, impure seed imponed from Europe and suaw used as packing material (references in Whitney 1994). The presettlement origin of the native North Arnerican species of old fields is sornewhat more questionable. Many species are known to have mignted eastward from the prairie regions after forest clearance (many examples in Voss 1972, 1985, 1998). but the fact that most old field natives currently have primarily eastem distributions rules this out as a general hypothesis. Marks (1983) presents a good examination of the issue, suggesting that old field natives include both true pioneer species which took advantage of temporary forest openings caused by fire, wind or other disturbance as well as species which specialized in uncornmon but persistently open habitats such as cliffs, rock outcrops, barrens and prairie outliers. Marks feels that the latter of the two modes applies best to most native old field species. Cenainly the presence of many typical old field natives in naturally open communities in Ontario today (Catling and McKay-Kuja 1992, Catling and Catling 1993, Catling 1995, Catling and Brownell 1995) implies that these areas could have been important sources for native colonizers of newly cleared land.

Old fields and sirnilar open habitats are often used as a mode1 system in plant ecology in both Europe and North America because they are usually readily available around any settled area and because their successional nature means that studies can be more rapid and tractable than many of those in longer lived communities such as mature forests. Old fields generally contain a mix of native and alien species (Curtis 1959, Maycock and Guzikowa 1984), and therefore they offer good opportunities to examine differences between the two. CWAPTER 1 : GENERAL INTRODUCTION

OBJECTIVES The general goal of this thesis is to investigate the role of natural predators and pathogens in seed ecology, and in particular, to understand their role in the establishment and spread of exotic species. Using old fields as the study system, this thesis is intended: a) to provide background information on the site and biological setting of these experiments (Chapter 2) b) to determine whether seeds suffer significant losses to predators before incorporation into the seed bank (Chapter 3) C) to determine whether seeds suffer significant losses to seed predators and pathogens in the seed bank (Chapter 3,4) d) to discover whether seed losses to natural enemies differ among species (Chapter 3.4) e) to determine whether seed losses to natural enemies differ between habitats (Chapter 4) f) to determine whether seeds of native and alien species differ in their susceptibility to natural enernies (Chapter 3,4) g) to determine wheti-ier differences in seed losses between natives and aliens occur independent of their phylogenetic relationship (Chapter 4).

Chapters 3 and 4 represent two different approaches to the problem of whether aliens and natives differ with respect to their natural enernies. Chapter 3 represents a "traditional" comparative approach using a very broad range of potential colonists; this chapter documents whether differences exist between locally occumng natives and exotics. Chapter 4 represents a more refined experiment using congenenc pairs of natives and exotics; this chapter documents whether exotics differ from close relatives, which are expected to share many seed characteristics. Results in both chapters may reflect both the escape and filter hypotheses, but by asking whether exotics differ from the values othenvise expected for close relatives. Chapter 4 provides a more direct test of the escape hypothesis. CHAPTER TWO

VEGETATION OF JOKER'S HILL CHAPTER 2. JOKER'S HTLI .; VEGETATiON

Introduction Southem Ontario, like most of eastem Nonh America, has been highly altered since European settlement. Natural areas have been greatly reduced and fragmented and entirely new communities made up of a mix of native and alien species have become a prominent feature of the landscape (Riley and Mohr 1994). The range of communities with different histories of human disturbance at Joker's Hill offers good opportunities to study the factors important in plant community development. Portions of the forests on site are unusually mature and undisturbed and bear a strong resemblance to the habitats present before settlement, while the old field and early successionai forest sites are typicai of much of the altered southern Ontario landscape. In this chüpter 1 present an overview of the major plant communities of Joker's Hill. giving special reference to detailed examinations of the representation of native and alien species above and below ground in the old field habitats. These descriptions of old field communities providr an understanding of the biological setting in which 1 conducted my experiments, they help to justify the sets of species used in rny experiments, and they demonstrate that seed banks and seed biology play a role in the ecology of these meadows.

Prior to the work presented here, little information on the natural history of the site existed and nothing was in a form readily accessible to university researchers. In addition to outlining the plant communities which comprised the setting for my research, this chapter and the complete species lists of vascular plants, birds, mammals, reptiles and nmphibians (Appendices 1 to 5) are intended to provide baseline data which will be important for future researchers at Joker's Hill. 1 hope they also serve to increase awareness within the University of Toronto community of the outstanding and rare natural features of the site.

Site overview The Joker's Hill property, also known as the Koffler Ecological Research Station, occupies 348 ha in King Township, Regional Municipality of York. immediately West of the city of Newmarket (see map, Figure 2.1). Property boundaries are somewhat irregular, but are contained within the quadrangle formed by Highway 9 to the north, Bathurst Street to the east, Keele Street to the West and the 19th Sideroad of King Township (Mulock Drive) to the south. Dufferin Street cuts north to south through the centre of the site. The property was donated to the University of Toronto in 1995 by Murray and Marvelle Koffler, in one of the largest single donations of property ever given to a Crinadian university. The Kofflers acquired approximately 200 ha of the property in 1969 and then added several peripheral properties in the western end after that (W. Fox, pers. cornrn.).

CHAPTER 2. JOKER'S HILL: VEGETATlON

Approximately one third of the property is managed as manicured grounds and agncultural land. Almost al1 of the buildings and anthropogenic habitats are dong and to the West of Dufferin Street. The largest proportion of the managed grounds are associated with the large boarding stable operation, which includes three bms, a reception building, approxirnately 35 ha of active hay fields, 15 ha of mown show jumping grounds and accomodation for a small number of employees. Other buildings on the property include a small field house for researchers, seven rental houses and a large, enclosed gazebo. Aside from the development of an increased network of trüils and a small maple sugar bush in t 97 1, the remaining two thirds of Joker's Hill were subject to minimal human disturbance under the Koffler's ownership and are in excellent condition as a result. Vegetation at Joker's Hill includes unusually extensive and mature examples of several upland forest types and seepage swarnp communities typicril of the Oak Ridges Moraine. These very high quality communities are well buffered on most edges by younger forest. conifer plantation and old field communities. Native species richness is unusually high for the level of habitat diversity present (S. Varga, OMNR Inventory Specialist, pers. comm.) and there are numerous significant plant species present (Varga 1999). In 1999, partly as a result of the work presented here, the Ontario Ministry of Natural Resources (OMNR) has recognized the exceptional quality of the forest comnunities at Joker's Hill by proposing them as a Life Science Area of Natural and Scientific Interest (ANSI).

Lnndforms and early human ltistory of ~oker's'fiill Away from the areas described above, Joker's Hill is predominantly natural forest with a variety of conifer plantations and old field habitats also present. The site sits in the western portion of the Oak Ridges Moraine, and contains some of the highest elevations on the moraine. Elevations range from 260 m dong the creek at the extreme West end of the property to 347 m near the corner of Dufferin Street and the WhSideroad. There are few flat areas on the property; most of the site, including al1 of the mature forest, is on ruggedly undulating kame deposits (Ontario Natural Heritage Information Centre 1999). Most of the cleared land in the western third of the property is on more gently rolling Kettleby and Newmarket Tills. OMNR includes most of the eastem part of Joker's Hill in the provincially significant Glenville Hills Kame Earth Science ANS1 because of the excellent representation of kame moraine features, which are uncornmon on the western part of the Oak Ridges Moraine (Ontario Naturd Heritage Information Centre 1999). The soils on the property are predorninantly fine sandy loarns and silty sand loams, with organic accumulation in some wet bottomlands (P.M. Kotanen, unpublished data, CSB pers. obs.). One of the outstanding features of the site is the number of springs and groundwater seepage areas at the bases of the steep slopes. The groundwater flowing from these areas feeds several small creeks which flow northward into the Holland River. Two of these creeks have been dammed to CHAPTER 2. JOKER'S HILL: VEGETATJON create three small ponds, two in the open land West of Dufferin Street and one in the forest to the east of Dufferin Street. An additional spring fed pond has been dug along the driveway leading to the stables.

European settlement began in the area in the early 1800s. Forest cover in King Township was reduced from >95% before European settlement, to 608 in 1840, to a low of 4.9% of ungrazed forest in 1938 (Riley and Mohr 1994). With natural reforestation and the developrnent of conifer plantations, forest cover in the township had recovered to 22% by 199 1 (Riley and Mohr 1994). The Joker's Hill property itself was likely settled as several small famis. Around 1950. howevcr, most or al1 of the current property was purchased and developed as an 800 ha hone farm and estate. Over time. the land base was reduced until purchase the Kofflers (Rasky 1984, W. Fox, pers. comm.). The fact that the property has been operated primarily as an estate farm for approximately 50 years, rather than as a srnaller, more typical southem Ontario farm, has been important in the retention of high quality. old growth forest on site. Woodlots on most profit- driven southem Ontario farms tend to be logged at fairly regular intervals.

Native plant cornniunitirs: The hisroric serting Historically, the property would have been almost continuously forested, with the exceptions discussed below. The rnost mature sugar maple and hernlock dominated forests on site are probably very typical of the forest types which predominated in pre-European times. Bnsed on the large number of trees which appear to be in the range of 150 - 200+ years old, core areas of the forest were only lightly logged and were never cleared.

Much of the most mature forest on site includes a significant proportion of conifers; pnmarily hemlock and white cedar with some large white pine. Many steep, north facing dopes are hemlock dominated and the valleys dong the sinall creeks have extensive high quality seepage swamps of hernlock and white cedar, with some yellow bircb, black ash and red maple. Very mature examples of hemlock - white cedar seepage swamps occur in the northwestem corner of the property and to the east of Dufferin Street along the boundary with the Thornton - Bales Conservation Area. These habitats support species such as Dennstuedtin punctilobula. Corallorhiza maculata, Oxalis montanu and Vibumum lanranoides which are typical of more northem forests in Ontario. The small inholding (not owned by the university) within the east end of the property, dong the Bathurst Street road allowance, is a somewhat different white cedar - white pine swarnp conaining several additional significant species (Ribes lacustre, Maluxis monophyllos and Moneses unflora) associated with coniferous forest. Deciduous forests dominated by sugar maple occur in some areas of intermediate moisture. The best exarnple is west of Dufferin Street, where kame material meets the richer tills. The old growth forest there is predominantly sugar maple, with beech, red oak and white ash also common. This stand is exceptionally mature, with numerous trees over 60 cm dbh. Along with the more common understory flora, the herbaceous layer in the deciduous forests at Joker's Hill includes several locally rare or uncommon species typical of very rich-soiled forest sites (e.g.. Dryopteris goldiana, Athyrium thelypteroides, Orchis spectobilis, C. hitchcockiana. C. dhursir~a ruid Panax quinquifolia).

Open wetlands are nther restncted at Joker's Hill. Diverse marshes dominated by combinations of Typha lotifolia. Scirpus spp., and Eleocharis erythropoda occur at the forest pond and along a small creek near the southwest edge of the propeny, and Typhn stands occur around the perimeter of the gazebo ponds. An unusual fen-like wetland system is also present on a gently sloping area with extensive groundwater seepage, immediately east of WM. In openings among white cedür - willow thickets. several fen associated species (Appendix 2) occur among Carex spp. and Equisetum spp. dominated comrnunities. The presence of certain obligate open wetland species like Carex iasiocarpu and Solidago uliginosa suggests that this area may have been at least partly open historically; perhaps as a result of regular windfalls caused by the instability of the seepage slope.

In the eastern end of the property. soils are very dry kame sands. The forest is mostly well under 100 years old. Red oak and largetooth aspen are dominant with red maple, white pine and some sugar maple also present. Historically, this area was probably relatively open oak and pine foresi. On some of the ridge tops which are currently sparsely treed shmb thickets, dry conditions and reiatively frequent fires may have maintained natural openings. Some herbaceous species typical of prairies and savannahs (e.g., Calystegia spirhameus, Galium lanceolarum, Solidago arguto and Symphoricarpos albus) are still present in these areas. These naturatly open sites may have been the source of some of the nurnerous native, prairie affiliated species which now occur in the dry old fields of the northeastem corner of the propeny.

Oldfields: The study systern While the preceding vegetation types probably resemble the original vegetation of the site, old fields form the focus of this thesis. They were created through human removal of the original forest and the rnix of native and alien species present reflects the history of human use on site. Species composition in the numerous old field habitais present at Joker's Hill varies in response to age since abandonment, intensity and type of agrîcultural use and moisture level. among other CHAPTER 2. JOKER'S HJLI.: VECiETATION factors. Open areas represent a continuum frorn active hayfields which are cultivated in dfalfa (Medicago sativu) and alien pasture grasses. to long abandoned areas which were cleared historically but probably never ploughed. Much of the land which was once cleared at Joker's Hill has since reverted to natural forest or been tumed into conifer plantation. The ratio of native to alien species in the rernaining old fields varies substantially. Mesic, recently abandoned hayfields tend to be heavily dominated by alien pasture grasses. especially Pon prntensis and Bromus inermis, with fewer native species. Some of the drier fields are dominated by the native graminoid species Pou compressa (questionably native. Voss 1972). Dontlmlin spicata, Sporoholus cryptondrus and Carex pensylvanica.

The native species in old fields at Joker's Hill include some ubiquitous species of open, disturbed areas such as Solidago canadensis, Rubus strigosus and Erigeron annuus, which likely previously persistcd in temporary openings created by wind and fire. As suggested by Marks (1983). however, the native flora of the old fields seems to be primarily made up of species which specialized in historic times in more persistently open marginal habitats such as shorelines, rnarshes, dry prairies and savannahs. As discussed above, species of praine and savannah communities (Riley 1989) are unusually well represented at the site (see also Appendix 3). Many of these species may have invaded artificially cleared areas from dry, open ridge top communities in the immediate area. Others may have spread from further afield. Patches of time prairie habitats are present less than 10 km northeast of Joker's Hill at Holland Landing (Reznicek and Maycock 1983) and prairie remnants become more common further east dong the Oak Ridges Moraine and southwest toward the western end of Lake Ontario (Catling, Catling and McKay-Kuja 1992, Catling and Catling 1993). Additionally, many of the common native species of the wetter old fields likely spread to cleared areas from nearby wetlands. Species such as Eupntorium macuhtum, E. pr@olintum, Elithamia gmrninifolin. Aster lmtcrolutus and A. puniceus, among many others, are typical of the open wetlands on site.

Many of the alien species present in the old fields undoubtedly arrived with the first European settlement, as has been documented elsewhere in North America (Whitney 1994). Forage grasses and legumes probably were extensively introduced to the site with the onset of farming. European settlement in North America dso inevitably brought a wide range of unintentional introductions as a consequence of impure seed mixes and other inadvertant transport (references in Whitney 1994). The fact that this type of unintentional introduction continues today was evident in observations of the year to year variation in weed communities in disturbed areas around the houses and stables on the property (CSB,pers. obs.). Another significant source of introduction on site is gardening. Historicdly, many herbs probably were introduced by settlers ÇHAPTER 2. JOKER'S HILL: VEGETAïïON on site for cooking and medical use, though their distributions today are probably primarily a consequence of natural dispersal. Currently, ornamental herbs, shmbs and trees are extensively planted on the property. Some of these have spread to natural communities and represent potentially problematic invaders (e.g.. Lonicero tatarica and Lonicera x morrowi; Luken 1988).

Survey methods The local species pool: Overall vascular plant species pool Beginning in May 1997 and continuing through to July 1999 1 rnaintained a list of vascular plant species observed on the Joker's Hill property and in the immediately surrounding natural areas. This list represents the pool of native and exotic species which actually or potentially occur in my study sites. 1 made a substantial effort to cover al1 pans of the property and every habitat type. New records were obtained in almost every month of the year, but search effort was concentrated from May to October. Voucher specimens were collectçd for di fficult to identi fy species and for species considered locally significant. Difficult identifications were confirmed with the help of P.W. Ball, at the Erindale Herbarium (TRTE). Voucher specimens will be deposited at the Royal Ontario Museum - University of Toronto Herbarium (TRT).

Species presertce and abundunce esstimlrtes for main field sites Vascular plant species lists for the Dead Man's Curve (DMC) and Wet Meadow (WM) field sites were developed through careful inspection of the two fields during the growing seasons of 1997 and 1998. This list represents the species which have successfully established in the imrnediate area of my primary study. Both of these sites are oldfields. DMC is located on a steep ridge in the north-central area of the property; WM is a more gently sloping and wetter site in the southwest corner. WM was managed as a hayfield until approximately 10 years ago. Management of the site during that time consisted of ploughing and seeding the field with a hay mix (primarily Medicago sativa and Phleum pratense) roughly every four years (W. Fox, property manager, pers. cornm.). In contrast, DMC has had no significant anthropogenic disturbance since at least 197 1 (W. Fox, propeny manager, pers. comm.). The steepness of the dope has probably precluded ploughing over much of the site and some fairly large trees suggest the site has been left for a considerable time. Stone piles around the more gently sloping lower part of the field suggest that it may have been histoncally cultivated. The area covered by the lists is bounded by the corners of the experimental gnds established by P.M. Kotanen on the DMC and WM sites. The Kotanen grids were made up of rows of 1.5 m by 1.5 m plots. Within a row, plots were separated by approximately 5 m, and rows were separated by 10 m; thus the plots themselves covered only a small portion of the total area surveyed. Atypical areas (shadrd spots under trees, frost hraved areas of low plant cover, rock piles and shmb thickets), which CHAPTER 2. JOKER'S HU.1.: VEGETATION were deliberately avoided when placing plots, were searched for species not present elsewhere in the fields. The experimental treatments performed on some of the Kotanen plots included the removal of existing vegetation and the addition of seeds of 43 native and 54 alien species, some of which were not previously present in these fields. Species which appeared naturally only in the soil disturbance plots were included in the overall species totals, with notation indicating the origin of the record. Species present in the field only as a result of experimental seed addition, and species recorded only in indoor seed bank germination trials, were not included in the list.

Species abundance was quantified using the unmanipulated control plots in the Kotanen grids üt DMC (n=43) and WM (n=4 1). The plots were carefully examined for approximately ten minutes and every species present was recorded. Abundance for each species was estimated on a scale with the following categones: 1 - 1 to 9 rarnets present in plot, 2 - 10 to 49 ramets present in plot, 3 - 50+ ramets present in plot. Two abundance indices were calculated for each species; first the number of plots in which a species occurred was counted and second the abundance estimates for each species in each plot was summed.

Seed bank estimation for main field sites Germinable seed banks at both Joker's Hill field sites were assessed by germinating soil cores in the Erindale College greenhouse. Cylindrical cores 5 cm in diarneter were collected to 10 cm depth with a bulb planter. The sidrs of the cylindrical cores were cut square to eliminate the effects of seed movement between the bottom and top layers during collection. This left cores which were 5 cm x: 5 cm x 10 cm deep. These cores were divided into upper and lower halves. which were gerrninated separately. Cores were collected in December 1997 (40 cores per site) and May 1998 (20 cores per site). Soi1 from each half core was spread thinly (m. 0.5 cm) over soilless potting mix in a 12 cm x 20 cm tray and was kept moist for 90 days under an automatic sprinkler system. Seedlings were counted and thinned roughly once a rnonth before the final count after 90 days. In order to determine if seeds were evenly distributed by depth, difference values were generated for each species in each core, by the formula: difference = seedlings in top half of core - seedlings in the bottom half of core. One sarnple sign tests were then conducted on data grouped by; 1) site and trial and 2) species (within a site and trial), in order to determine whether there were significant differences between soil fractions. CHAP'ER 2. JOKER'S HILL: VEGETATION

Results and Discussion Overall vascular plant species pool As of July 10, 1999,437 native and 166 alien species were identified for the Joker's Hill property and immediate surroundings (Appendix 1). Almost al1 of these species were recorded within the Joker's Hill boundaries. Records for only 12 species (0.2% of total) were based on species recorded only in adjacent areas but not on the property itself. The native species total is a rather high species richness for southem Ontario. For example, Brownell and Blaney (1995) plotted native species richness vs. log (area) for 18 natural areas inventoned in the Lower Trent Watershed in eastern Ontario. The Joker's Hill data point would be well outside the 95% confidence interval on their graph. The estimated divenity of the site is partly a consequence of the unusually complete coverage made possible by continual searching over several field seasons, but also reflects the high quality of the habitats present. The proportion of alien species on the list (27.3%) is typical or perhaps slightly lower than average for a site with extensive anthropogenic habitats (S. Varga, pers. cornm.).

Rnre native plant species Of the 437 native vascular plant species recorded. 57 are significant at some level between local and national rarity. The list of significant species, with rarity level, status and habitat in the area. is given in Appendix 2. Again, this total is unusually high among local natural areas (S. Varga, pers. comm.). Most of the significant species are associated with one of five habitat types. Sixteen rare species. mostly those typical of southem Ontario prairies. were found dry open areas. Nine rare species were in cedar - hemlock swamp, seven rare species were in dry red oak dorninated forest and six rare species were in each of rich deciduous forest, calcareous (fen-like) seepage marsh and mixed herdock - sugar rnaple forest. The remaining seven rare species were found in various disturbed habitats.

Species presence and abundance in main field sites At the DMC field site, 8 1 native and 41 alien species were found in the area of the Kotanen plots (Table 2.1.). At WM, 62 native and 38 alien species were found (Table 2.1). At the scale of the single plot, species richness (25.5 spp./plot) was substantially greater at DMC than ai WM (14.5 spp./plot). At DMC, 27 species were found in >50% of al1 plots (Table 2.2), while at WM only 8 species were present in >50% of plots (Table 2.3). At WM Pua pratensis and Solidago canadensis are uniformly abundant across al1 plots, with just a few other species consistently present (Table 2.3). Vegetation at DMC was much more heterogeneous. No species were found in al1 plots and dominant species varied between plots. At DMC, 15 different species were CHAPTER 2. JOKER'S HILL: VEGETATION recorded at Ieast once in the >50 ramets/plot abundance category, compared to just 6 species in the sarne category at WM.

Severai factors contribute to the difference in overall species richness between the DMC and WM sites. The greater age of DMC is Iikely important, both in allowing time for invasion of species from sumounding areas and in producing a greater habitat heterogeneity because of the presence of more trees. Shaded conditions under the larger trees limit the highly cornpetitive open field grasses and provide a microclimate suitable for a substantial number of forest species not found in open areas at DMC.The trees also act as foci for the invasion of bird and animal dispersed species because of their use for perching and shelter. The drought prone nature of DMC and the naturd disturbance of its steep slopes by soi1 slips and frost heaving appear to be important in maintaining high species richness, at both the whole field and the plot scales. These factors prevent formation of the dense stands of Pou pratensis with thick litter layers iypical of WM, which probably greatly inhibit seedling establishment (Gross and Werner 1982. Rice 1985). CHAPTER 2. JOKER'S HILL: VEGETATION

Table 2.1. Species present üt Deüd Man's Curve (DMC) and Wet Meadow (WM) field sites, within the area of the Koianen plots. Species are in taxonomie order and are listed alphabetically within families. Nomenclature and native (N)or alien (A) origin follow Morton and Venn 1990.

Species DMC WM Species (cont'd) DMC WM Species (cont'd) DMC WM ll~~ecies(con t 'd) DMC WM 'carex cf: cristutellu x I~M~~~cu~osutiva x NPitz~sstrobus x varex grucillirnu x Uhtr us unrericarta x x Melilorus alba X X APinus sylvestris x N~arexgrariitluris x x ACerasriutriforirariutri x x Trifalium hybriduni x 'Jurr iperus cort~niioiis x carex leptotierviu x Asilene vulgur-is x N~uriiperirsvirgiriiuria x x Netuexpedrricit lura x N~t~rrrioriecylirtdrica x Vicia cracca ~hujaoccidenrulis x carex ymsylvurricu x N~~ier~ionevirgirriarra x x Vicia sariva A~grosti.~gigaritea xxN~arex vulpirioideu x N~quilegiaca~iadettsis x Ribes aniericatio x N~cirpusutrmirens x A~ariirticirlirsacris x x Ribes rubruni x '~uricusdirdleyi x x intun tu ni clteirarithoides x Agrin~oriiagryposepala x A~sparngusoficiriulis x "Malus purriilu x x II: Atnelurichier laevis x ACrataegusttionogynu x "Festuca aritriùitiacea x x *Pru r tus serotiria x NCratueguspuricruta x

NC;lyceriastriatu x Crataegus sp. X X

N~ragariavirgitiiaria X X %eitrn allepyiciinr x x NO-valissp. x

X

POO cotripr.~.ssa x x Strlix bebbimilr x Rubirs srrigosus x x Rhus typliina X X

A POU y rarerisis x x 'Sulix discolor x x 'Sorbus air cirpcrriu x Toxicodendroti radicaris x N~poruliolirstteglecr~rs x 'Sulix eriocrplicr lu x 'Desniodiunicutiadetise x Celasrrus scaradetis x NC(~rexuureti x x 'Salix yetiolrr-is x x 'brrts conliculc~tus x Cc~r~orcotn twuis x Jrrglnris cirier-eu x 'Metlicugo Irrpitliriu x x

Seed bank estimation in main field sites Cornparisons of the total seed bank density with other seed bank studies are complicated by differences in meihodology. Depth of sampling, season of sampling (and thus the inclusion of the transient seed bank), and methods of enumerating seeds Vary across studies. Despite these limitations. the total germinable seed banks recorded at the WM (30800 seeds/rn2tu 10 cm depth ) and DMC (15730 seeds/m2 to 10 cm depth) sites (Table 2.4) were still within the range that has ken reported in other temperate old field sites (Rice 1989). The higher total at WM was probably reflective of the recent history of hay cultivation on the site, as seed nurnbers are often larger in arable field seed banks than in old fields (Cavers and Benoit 1989).

The two sites were similar in that species richness detected in the seed bank was much lower than that above ground (Tables 2.5, 2.6). At DMC,seed bank species richness was 24.1 % of that above ground while at WM, seed bank species richness was 37.6% of that above ground. This result was likely largely a consequence of sampling intensity. Above-ground species lists were developed by thoroughly walking the fields and species lists were reasonabiy complete, while seed bank sampling probably detected only the common species below-ground.

At both sites, the majonty of species in the seed bank were also found in the above ground vegetation, and the dominant above ground species (Pou pratensis, Poa compressa and the Solidago canadensis /S. altissima cornplex) were among the dominant species in the seed bank (Tables 2.1-2.6). These species made up roughly one third of the total seed bank at each site. Many of the differences between the sites at the species level are simply reflective of differences in the current above ground vegetation. Species such as Daucus carota, Hypericum perforatum and Monardaflstulosa were much more common in both the seed bank and the above ground vegetation at DMC than at WM while the reverse was true for Erigeron philadelphicus, Juncus cc dudleyi and Eutharnia grarninifolia. Numerous above-ground species were not detected in the seed bank, notably Brornus inemis, which was locally dominant at both sites. ÇHAPTER 2. JOKER'S HILI .: VEGETATION

Table 2.4. Germinable seed banks from top and bottom halves of cores from Dead Man's Curve (DMC)and Wet Meadow (WM) field sites, fall 1997 and spnng 1998 trials.

Site Trial Total seeds/m2 # cores % in % in Seedlings (10 cm depth) top 5cm bottom 5 cm DMC Fall 1997 276 2629 42 53.6 46.4 DMC Spring 1998 806 15730 21' 50.3 49.7

'The top half of one core was excluded because of loss during germination. Proportions were adjusted accordingly. ÇHAFI'ER 2. JOKER'S HILL: VEGETATION

Table 25. Geminable seed bank (menn seeds/m2 to IO cni depth SEM)at the Dead Man's Curve field site. $II

1997 (42 cores) and spnng 1998 (21 cores). Taxonomy and origin follows Morton and Venn ( 1990).

SPECIES OFUGIN FAU 1997 SPRiNG 1998 Hypericum perforarum rilien ' Paaceae sp. ' --- 2~olidagosp. native Erigerori strigosus native '~ieraciunisp. nlien '~ieraciunrcaespiiosuni alien '~ieracirtmpiloselloides alien Cure-r granula ris native Chnxzntherriunl leucarithemuni id ien '~olicia,~onenrarulis native Dartcrrs curota al ien Porr~ttillarecrtr alittn Verbascunt thapsus al ien Melilonts alba alien Rudbeckia hirra native Sporohofus ~ieglecrits native

Pariicrtnr ucuntinutuni nriti ve Euthnntiu grmiirriïi,lia native Awnio~iecyli~idricdvirgiriica native

Muriardu fisttllostr nriti ve Medicago lupulina alien Juticus cf: dudleyi native Oenothera biennis native Carex au rea native Patiicunt linearifoliurn native Pruriella vulguris native

Aster ri rophyllus native CHAPTER 2. JOKER'S HTLI .: VEGETATION

Table 2.5. Con tinued. SPECIES ONGIN FALL 1997 SPRING 1998

Clirtopodiunt vulgare native OIC) 20120 'T~phasp. native OIO 20120 Phleunl pratertse alien O*O 19120 Anteririaria neglecra native OIO 19120 unknown dicot --- 1 Oh39 195185 SAsreraceaesp. native 38~23 174198 TOTAL 26291457 15730k1375

'Most of the unidentified grasses were Pou mntpressu. (native) with some Asrostis giganfea (ah)and Poo prnrensis (alien). '~oliciogocatiadrrisis and S. ultissinta were not scpsrated in either trial. Thrse two species were not sepnrated froni S. trerrmralis in the fall 1997 trial. 'Hiemcium caespitosuni and H. praterzse were noi sepanted in the FaIl 1997 trial. The Hieraciim sp. total in the spring 1998 trial is the sum of the two species' totals. 'The single îjpka sp. seedling may have resulted from a seed blowing into the greenhousr from outside. No suitable habitat for the species is present at DMC, although it does occur within 50 m of the site. 'Undifferentiated Asterxeae were primarily Solidago spp. and Erigero~lstrigosiu which did not rench an identifiable size before the final seedlinp count. CHAPTER 2. JOKER'S HILL: VEGETATION

Table 2.6. Germinsble seed bank (mean seeds/rn2 to IO cm depth I SEM)nt the Wrt Meadow field sia. FiII 1997

(30 cores) and spring 1998 ( 18 cores). Taxonorny and origin follows Morton and Venn (1990).

SPECIES ORIGIN FALL 1997 SPRING 1998 Solidago canaderzsi.~/altissirrm native Etàgeruti philadelphicus native Juncus c$ dudleyi native Poteririlla tioniegica '? Plantago major alien Carex granularis. native Hypericunt perjoratum alien Eutharriia granlinifolia native Erigerm aarinuus native l~,qrostisgiganrea al ien 'Pouprurensis dien ' Pou coniprma native 'gras sp. ' --- Chrysarrthentum Ieitcantherntrnt alien Carex cf: cristarella native Rudbeckia hirtu native Oeriathera bietttris native Panicunz capil lare native Verllascuni thapstrs dien Asrer riovae-angliae native Cerastitm fontanuni alien Carex L$ aurea native Daucus carora alien Rubus srrigosus native Capsella bursa-pastoris alien Lycopus antericartus native Plart rago laricealara alien Vicia crucca alien Taraxacurn cf. officinale alien Erysimum cheiranthoides alien Verorticuserpyllifolia alien CHAPTER 2. JOKER'S HILL: VEGETATION

Table 2.6. Continued SPECIES ORIGIN FALL 1997 SPRlNG 1998 Trifoliunz pratertse alien Od 22222 Cirsiunz vulgare alien OIO 22122 Hiemcium caespitosum dien OI0 22k22 Sorlchus arvensis al ien Ih10 0I0 Mortardu fistutosa native 10I10 OI0 unknown dicot --- 1 03128 22122 unknown Erigeron/Sdidagn sp. native 153135 O& TOTAL 4 1 74k4-15 3080Ck43 10

'Pua pratensis (alicn). Poa compresse (native) and Agrostis gigantea (alien) wcrr not sepanteci in the fall 1997 trial. The grriss sp. total in the spring 1998 trial is the sum of these three species' totals. 'Very similar native and alien foms occur in Nonh Arnerica (Voss 1985); germinated plants were not distinguishable. CHAPTER 2. JOKER'S HILL: VEGETATlON

Most seed bank studies find considerable differences between the species composition of the above ground plant communities and the soil seed bank and this is especially true in successional grasslands (Major and Pyott 1966, Rice 1989, Thompson 1987, 1992). Above and below ground differences were present to a much greater extent at WM where 8 cpecies, including the very common Poteniilla norvegica, were in the seed bank but not present in undisturbed above ground vegetation. Al1 8 of these species were ruderal annual or biennial species, a pattern well known in retired arable land (Chippendale and Milton 1934, Dore and Raymond 1942. Chancellor 1986). At WM the uniformly dense vegetation currently leaves little habitat for highly ruderal species. The only obvious natural source of bare soil was a smali nuinber (4)of large ant mounds. The more diverse and numerous rudenl seed bank at WM is presumably remnant from the period when the site was an periodically ploughed hay field. This type of disturbance regime is likely to produce large seed banks of ruderal annuals and biennials. These species reproduce abundantly from the seed bank in the first one or two surnmers after ploughing, before the perennial grasses become too dense. This sequence was observed in several currently active Joker's Hill hay fields which were ploughed and seedrd in 1997 and 1998. resulting in an abundünce of annuals such as Panicum capillare. Clze~zopodiii~irzllm~i and Anznrnnthus retroflrxus, al1 of which have since become much less common (CSB, pers. obs.).

At DMC, ruderais were less prevalent in the seed bank. Among seed bank species, only the exotic Verbascuni thapsits was absent above ground. Verbascum thnpsits produces very large numbers of seeds per plant and is well known for the extreme longevity of its seeds in soil. Along with V. blnttrtrin, it was the longest lived species in Dr. Beal's 100 year seed bank experiment (Kivilaan and Bandursky 198 1). A few native ruderal species were present in the both the seed bank and the above ground vegetation of DMC.Oenotlrem biennis, with a long lived seed bank (Kivilaan and Bandursky 1973) and biennial life history similar to Verbascurrr, and the annual grass Sporobolus negiecttts are the best examples. Though this site has not been ploughed for at least 30 years (if ever), natural soil disturbance is much more substantial at DMC than at WM. The steep, south facing slope at DMC results in occasional soil slips and a high variance in spring and fall temperatures, which causes frost heaving (Kilburn, unpublished thesis). These processes leave approximately 15% of the field as bare soi1 or with very low plant cover. This natural disturbance is the preferred habitat of the native annual grass Sporobolus nciqlectus (Blaney, pers. obs.) and is probably important in the persistence of the other ruderal species in the above ground vegetation. The persistent seed bank of Verbascum could be the result of occasional reproduction in natural disturbances since the field was cleared or could remain from a single large disturbance (perhaps even the original cleanng of the site) from greater than 30 years ago. CHAPTER 2. JOKER'S HTLJ .: VEGETATTON

The relatively even distribution of seeds between the upper and lower halves of the 10 cm deep cores (Table 2.4) is probably explained ai WM by the history of ploughing (Roberts 198 1). The occurrence of the same pattern at DMC, where ploughing has not occurred in many years, is somewhat more surprising given the number of studies where seeds are highly concentrated in the upper few cm of soi1 (Roberts 1981 and references therein). Historic human disturbance may have mixed the seeds into the deeper layers, or perhaps the activities of the biota in conibination with natural soi1 disturbance at DMC are sufficient to rnove seeds or creaie fissures by which seeds can enter the deeper layers.

The large increase in the total germinable seed bank detected in May 1998. as compared to thnt detected in December 1997. was somewhat unexpected (Tables 2.4-2.6). It is almost certain thüt overall seed numbers are highest in the ûuturnn after the shedding of the season's seeds but before the spring peak of germination. Most seeds produced in 1997 would have been shed from the parent plants by the December 1997 sarnpling and no seeds of any of the commonly occurring seed bank species would have been produced before the May 1998 sampling. Similarly, many of the seeds which were going to germinate in 1998 hûd probably germinated before the May 1998 sarnpling. Thus the second trial should have been sampling a smaller pool of seeds. It is likely ihat the spring increase was attributable to reduced dormancy of seeds andor spring conditions in the green house being more conducive to germination. Further evidence of the presence of viable but ungerminated seeds in the December 1997 sampling cornes from observations after the germination penod ended. Some samples were left in the greenhouse after the December 1997 germination trial was over. No funher seedling counis were done, but in May and June, nurnerous Ju~icusseedlings emerged frorn the WM samples (CSB, pers. obs.) from which no J~rncrishad yet been recorded.

Seasonal dormancy cycles have been documented in rnany temperate species (well summarized in Baskin and Baskin 1998). Dormancy cycles have, however, been somewhat overlooked in the literature exarnining total seed bank communities. In the studies which examine seed banks at the sarne site over successive seasons. the influx of shed seeds after the growing season is generally cited as the main reason for seasonal variation in total seed numbers. This may be the case in certain desert or Mediterranean grassland communities in which the seed bank is dominated by annuals. however my results indicate that changing dormancy status may cause seasonal variation of equal or greater magnitude. From a sarnpling perspective, the significance of dormancy cycles will Vary depending on the germination environment used. The fact that 1 was looking at the immediately germinable seed bank under natural day lengths in the greenhouse CHAPTER 2. JOKER'S HILL: VEGETATION

likely accentuated the effeci of dormancy cycling because the short days in winter may have been insufficient to stimulate germination of some seeds which otherwise would have grrminated. Also, if newly dispersed seeds were trapped by the upper layers of litter rather than becoming incorporated into the older litter or soil, they would been underrepresented since coarse litter was discarded before germination because of its potential inhibitory effects on germination.

The existence of domancy cycles ernphasizes the need to take more thrn one annual sampie in assessing the seed bank at a single site. There is no single "correct" time for seed bank estimation. Seed dispersa1 and germination occur virtually throughout the growing season, so the seed bank is in constant flux with any atternpt at estimation being just a snapshot of a point in time. My sampling methodology measured a consistent and biologically meaningful parameter: the germinable component of the seed bank, rnther than the total seed population.

Conclusions The Joker's Hill property consists of a mixture of forest, wetland, Field, and oldfield communities with widely different histories of disturbance and invasion. In particular, the oldfirld communities comprise a diverse mixture of native and exotic plants drawn from a large local species pool. Many of these species have persistent seedbanks, but the majority seem unable to maintain large buried seed populations. These results provide both background data and impetus for further study into the role that seed banks rnay play in determining which species cm establish and persist in oldfields. CHAPTER THREE

EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY CHAPTER 3: EXPERTMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Introduction The structure and composition of many ecosystems have been altered profoundly by biological invaders: non-native species deliberately or unintentionally introduced by humans into new regions. Since the 1950s many researchers have tned to develop general rules to help predict which species make successful invaders (e.g., Elton 1958, Baker 1974, Groves and Burdon 1986, Mooney and Drake 1986, Drake et al. 1989, Mack 1996) and which communities are susceptible to invasion (e.g., Crawley 1987, Mack 1989, Rejmanek 1989, Groves and Dicastri 1991). These effons have produced few, if any, rules with strong predictive value (Lodge 1993, Karieva 1996). One reason for this lack of success is the fact that diens are extremely diverse. Rules demonstrated to apply to one group (Le.. the genus Pinus, Rejminek 1995) rnay fail when applied to other groups. Another reason for the difficulty in developing a predictive ecology of invasions may be the methods used to denve the predictions. Early efforts tended to involve generalization based on correlative analyses of successful invasions, without much observation of unsuccessful invasions or resistant communities (Burke and Grime 1996). Some recent authors have looked at large species pools and used stronger correlational methods (e.g.,Mazur 1989, Scott and Panetta 1993, Crawley, Harvey and Purvis 1996, Williamson and Fitter 1996a, 1996b. Kotanen, Bergelson, and Hazlett 1997) but there are still very few explicit, experimental tests of hypothesized rules about plant invaders. As Burke and Grime ( 1996) state, "There is now an urgent need for the initiation of field experiments that test sorne of the more important invasibility hypotheses that have been genented from the study of past case histories."

One hypothesis is that some invaders succeed because they experience low risks frorn natural enemies (predaton and pathogens). There are two distinct ways this could occur. Both of these hypotheses argue that a low pest load is important to invasion. The distinction lies in the mechanism causing this low load. First, invaders rnay lose their natural enemies when they are transported to a new area (the predator escape hypothesis: Elton 1958, Crawley 1986). Alternatively, species with intnnsically low rates of seed predation rnay make better invaders because they are less likely to be elirninated by natural enernies in their new habitat (the predator filter hypothesis). These two hypotheses are difficult to distinguish, but the escape hypothesis predicts that invaders should have lower pst loads in new habitats, while the filter hypothesis predicts that pest loads are equally low in both original and new areas. As well, the escape hypothesis refers primarily to the loss of species-specific enemies, while the filter hypothesis is more likely to apply to generalist enernies.

There is some supporting evidence for both hypotheses. The strong host specificity of many plant pathogens and predators (Harper 1977, Dinoor and Eshed 1984, Crawley 1992) suggests CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALlTY

the potential importance of predator escape for plants arriving in new regions. Most alien plants, excepting ornamental species, are probably introduced as seed, meaning that that certain types of predators and pathogens are uniikely to have amved with them. It should be noted, however, that fungal and other pathogens are often transported on seeds (Neergaard 1977, Aganval and Sinclair 1997), so invaders may be less likely to escape from specialist seed-borne pathogens. The concept of predator escape is fundamental to biological control efforts, which often attempt to replace "lost" predators. Certain spectacularly successful biological control efforts, as with Oprtntia species in Australia (Mann 1970) and South Africa (Zimmermann et al. I986), and Hypericum per$orntitni in California (Huffaker and Kennett 1959) strongly suggest it to be true for sorne plant invaders. However, the fact that most biological control efforts fail (Crawley 1986) suggests that these examples may not be typical. Further evidence links predator escape at the seed stage to invasiveness. Some invaders have been shown to develop larger seed brinks in new regions than in their native habitats. Lonsdrile and Segura (1987) found that seed banks of Mimosa pigra were approximately 100 times larger in Australia than in its native range in Mexico. Research in coastal shrublands in Mediterranean climate zones of Australia and South Africa (Weiss and Milton 1984) has shown that seed banks of the reciprocdly invasive Acacia longifolia (native to Australia) and Chrysanrhernoides monilifera (native to South Africa) were increased 44 and 13 16 times in new regions.

There has been less investigation of the idea that species subjected to low pest loads make better invaders; however, the evidence that sorne communities resist invasion (e.g., Pimm 199 l), points to the possibility that the predator filter hypothesis may apply in some cases. AdditionalIy, correlations between seed size and predation rates, and between seed size and invasiveness (Crawley, Harvey and Pagel 1996) suggest that native and alien species rnay have intrinsically different rates of generalist predation, as predicted by the filter hypothesis.

Several other lines of evidence suggest that the seed stage may be important in understanding plant invasions. First, many plants (native and exotic) suffer the majority of their mortality at the seed stage (Harper 1977; Cavers 1983). Second, the seed stage is the primary opportunity most plants have for dispersal, which is necessary for the invasion of new areas (Harper 1977; Fenner 1985; Leck et al. 1989; Rees 1993). Third. many invaders have long term seed banks. Almost al1 of the world's worst weeds listed in Holm et al. (1977). for example, produce significant seed banks. Crawley, Harvey and Purvis (1996) found that British aliens were more likely than natives to have long term seed banks and Rees and Long (1992) found that 75% of species currently undergoing range expansion in Britain (both native and alien, but skewed towards aliens) produce long term seed banks. Seed banks may be important in buffering against the CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY stochastic hazards faced by small populations (Keddy and Reznicek 1982, Venable and Brown 1988, Rees and Long 1992, Rees 1993); invading species generally face these hazards repeatedly, both at the original site of introduction and with range expansion ris small colonizing subpopulations are formed (Barrett and Richardson 1986, Barrett and Husband 1990).

Much work has been done on post-dispersal seed predation (well summarized in Thompson 1987, Louda 1989b, Crawley 1992). though there is no published work that has focussed on differences between wild native and alien species. Rodents and ants are generally both important post-dispersal seed predators in arid Iandscapes (Reichman 1979, Abramsky 1983, Parmenter et al. 1984, Heskr, Brown and Guo 1993). In temperate grasslands, post-dispersal seed predation is genenlly Iess intense. and vertebrates (prinmily rodents) are generally the more important predators than ants (Mittelbach and Gross 1984, Hulrne 1994). although Reader and Beisner ( 1993) did find significant predation by ants at an old field not far from Joker's Hill. Predator risks ülso vqwith species-specific seed characters. For example, there is strong evidence that both birds and rodents prefer large seeds (Thompson 1987). Factors such as predator identity, seed abundance and dispersion and nutritional value can al1 affect the critical size beIow which seed predation by birds and mammals is reduced. Studies by Kelrick et al. (1986), Mittelbach and Gross (1984) and Reader (1993), however, suggest that seeds below 1 to 3 mg tend to escape predation by a wide range of vertebrates. In addition to ants, Collins and Uno (1985) and Crawley (1992) list seed bugs (Lygaeidae),seed beetles (Bruchidae) and ground beetles ris post- dispersal seed predators but note there is very little experirnental work exarnining the importance of these groups.

Although most rnortality likely occurs below ground for many long term seed banking species, there is strikingly little experirnental work examining the causes of that mortality in natural systerns (Baskin and Baskin 1998). Both bacteria and fungi in the soi1 are often suggested to be important in causing seed rnortdity. Paul. Ayres and Wyness (1989) reviewed the potential for the use of fungicides for experimentation in natural vegetation, but an investigation of fungal mortality in the seed bank of Minrosa pigra (Lonsdaie 1993) appears to be the first such study. Lonsdale found that fungicide significantly reduced seed losses by 10 to 16% over seven rnonths, but concluded that fungi were a less important source of seed mortality than germination associated with large temperature fluctuations. Crist and Friese (1993) examined survivorship of five species of seeds over 10 months under Wyoming shmb steppe and found that proportions of O decomposed seeds ranged from 6%to 93.5% by species. Although some important soil pathogens appear to be generalists (von Broembsen 1989), there is evidence of soil pathogens having some degree of host-specificity (Kirkpatrick and Bazzaz 1982. Van der Putten et al. 1993, Mills and Bever 1998), including soine seed pathogens of agricultural plants (Neergaard 1977, Aganval and Sinclair 1997). If species specific fungal pathogens are common in natural communities, the predator escape hypothesis would predict that natives would be more susceptible to thrm than aliens, which could have left their specific pathogens behind before arriva1 in North Amenca. If generalist fungal pathogens are more important, the predator filter hypothesis is more likely to account for any superionty in fungal resistance observed among invaders.

The impacts of soi1 fauna on seed populations below ground are understood only slightly better than are the effects of microorganisms. Crawley (1992) writes, "There is a great scarcity of data on mortality attributable to predators of dormant seeds in the soil. Protecting buried seeds in cages with a variety of mesh sizes should enable data on subterranean seed predation rates to be gathered without much difficulty, but so far as I know, such experiments have not been carried out." Baskin and Baskin (1998) thoroughly reviewed the literature concerning consumption of buried seeds by soil fauna. They found references to below ground seed consumption by mammals, earthworms, ants and slugs but they suggested that a wide range of other soil arthropods which feed on plant matter may also eat seeds (i.e.. millipedes, isopods, beetles and termi tes).

In this chapter I cxpenrnentally examine the hypothesis that alien species are less susceptible than natives to predators and pathogens. If this is indeed the case, either the predator escape hypothesis of the predator filter hypothesis could provide the explanation. In order to avoid some of the problems of previous work, 1 perform field experiments using suites of 39 to 43 species of open upland habitats, evenly divided between native and alien species. 1 focus on seed predation at two stages; 1) after dispersal but before incorporation into the long term seed bank (soil surface seed predation experiment) and 2) in the long term soil seed bank (seed bank mortality experiment). Along with the work outlined in Chapter 4, this is the first study cornparhg either seed bank or post-dispersal seed mortality over a wide range of CO-occurringnative and alien species. It also represents one of the first attempts to understand the role fungal mortality and seed predation by soil fauna in soil seed banks.

Methods Study site Both experirnents were conducted at the Dead Man's Cume field site at the University of Toronto Joker's Hill field station, Regional hlunicipality of York, Ontario (44O02'25" N, CHAPTER 3: EXPERIMENTAI. SURVEY OF NATTVE AND ALlEN SEED MORTALITY

79'32'00" W). The site is a dry-mesic old field on a south facing slope and has been abandoned from any agricultural use for at least 30 years. Soils are sandy and silty loarns. Vegetation is a diverse (74 native species, 4 1 alien species: Chapter 2) nix of native and alien species, typical of southem Ontario old fields (Maycock and Guzikowa 1984, Reader and Best 1989). Tree and shrub cover is approximateiy 10%. Grasses dorninate the site with the aliens Bromus inernzis and Poa pratensis important in mesic areas. Drier portions of the site are dominated by the natives Poa compressa and Danthoniu spicata. Cornmon native herbs inchde Solidngo canadensis, S. nemoralis, Antennaria neglecta, Aster urophyllus and A. novae-angliae. The most common aiien herbs are Hieracium piloselloides, H. cnespifosum, Melilotus alba, Medicago lupulina, Daucus carora. Hypericurn perforatunz and Chrysanrhen~umlruc~znthemum.

Experirwnîal Species The seed bank mortality experiment used 19 native and 20 alien species; the soi1 surface serd predation experiment used 22 native and 2 1 alien species (Table 3.1). Species were selected from a pre-existing collection of southem Ontario seeds. Al1 species are forbs or graminoids with wild populations occuming in the Regionai Municipülity of York (Riley 1989). Most of the species occur naturally within the Joker's Hill property (Chapter 2; Appendix 1). With five exceptions, seeds had been collected from wild populations in southern Ontario between June 1996 and June 1997. Seeds of Andropogon gernrdii, Bromus kalmii, Elytnus trncizycnulus and Sorghastrum nutans were purchased from the Pterophylla Fm.Walsingham, Ontario, where they had been grown in 1996 from plants originating from local, wild seed stock. Seeds of Digitaria ischneniunz were from greenhouse plants grown from local, wild seed in 1997. After collection, seeds were stored dry, in a freezer until use in the expenments. Species were selected to represent a range of taxonomie groups and for their habitat preference. Al1 species occur primarily or entirely in open, upland habitats and forest edges. CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.1. Experimental species for seed bank niortnlity (SB) and soi1 surface seed predation (SP) experinients. Presence on Joker's Hill research statian property (JH), and at the Deiid Man's Curve rtiseürch site (DMC)are indicated by "x". Native (N) or alien (A) origin follows Morton and Venn (1990) and nonienclrtture follows Gleason and Cronquist ( 199 1 ).

Fümily Species Expt. JH DMC Fririiily Species Expt. JH DMC CY PERACEAE ''~(~rex~tiu~i~eribergii SP

APIACEAE A Daucus cri rotcl SP, SB CY PERACEAE "Carex spicata SP ASCLEPIADACEAE NAsclepicissyriwa SP, SB DIPSACACEAE *~ipsncirssylvesfris SP, SB

ASTERACEAE A~ rctiirm rriirrirs SP. SB FABACEAE N~esntodi~rmcarraderise SP, SB ASTERACEAE rtertiesin cnrtrpestris SP, SB FABACEAE NLespedezacnpitata SP. SB ASTERACEAE Aster ericoides SB FABACEAE A~edicagoIrrpitlirtu SB ASTERACEAE *Ch~sar~tke~)irr~nleucarirlienirrni SP, SB FABACEAE * Melilntus alba SP*SB ASTERACEAE AHierc~cirrt~~critrtiririwutrr SB FABACEAE * Vicia craccu SP, SB ASTERACEAE NHieracirrnisc~brrrrri SB LAMIACEAE N~edeoniaIiispida SP. SB ASTERACEAE Solidago rieniorrrlis SP, SB LAMIACEAE ALeoriuruscardiaeu SP, SB BORAGINACEAE AEcIri~~r~iwigclre SP, SB LAMIACEAE "~orrardajisrulosa SP, SB BORAGINACEAE NHackeliavirginicm~ SP, SB LAMIACEAE ANepetrr cataria SP, SB BRASSICACEAE *Alyssu rrr alysuides SP ONAGRACEAE "~etrotherabientiis SP, SB BRASSICACEAE 'Arrrbis glubrrr SP PLANTAGINACEAE APla~itagonwr SP, SB BRASSICACEAE AErysi~mmcheircitrtlinides SB PLANTAGINACEAE NPlutitugorugellii SP, SB CARYOPHYLLACEAE !Werie aritirriiiria SP POACEAE N~~idropogo~~gerardii SB CARYOPHYLLACEAE ASilene vrtlguris SP, SB POACEAE N~rorrrusknlriiii SP, SB CHENOPODIACEAE "Cher~c~pndiurr~~lbirni SP. SB POACEAE *Brorrrrrs tectoruni SP CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.1. Continued. Faniity Specics Expt. JH DMC Fain ily Species Expt. JH DMC

POACEAE ADigitcrricrischuer)ilrt~~ SP SCROPHULARIACEAE N~e~istemriIiirsir~irs SP, SB

POACEAE A ~lytr~rrsreperls SP, SB SCROPHULARIACEAE A Verhmctrnr rliclp.uts SP,SB x x POACEAE N~lyniirstracl~ycairlirs SP, SB POACEAE NPatiicrrmlitieurifoliirni SP Soi1 surface seed 43 species 22N 18N 9N

POACEAE A ~lrleurrlpruterise SB predation experinient 21A 15A 8A POACEAE NSnrglic~striir~irrittclrts SP, SB

POLYGONACEAE A Rurriex crispus SP, SB Seed bank inortaliip 39 species 19N I1N 8N RANUNCULACEAE '~wrmriecjlittiiri~*u SP, SI3 expriment 20A 18A 1IA RANUNCULACEAE "~~~~riiriciiliisr/~ontboi&iw SP ROSACEAE "~eiinialeppicirrn SP, SB Total 50 species 25N 16N 9N ROSACEAE AGeitnrirrbmiirni SP 25A 22A 13A ROSACEAE Poterltilla arguta SP, SB ROSACEAE "uteritillrr recta SP, SB

LAMIACEAE A Nepeta catariu SP, SB ONAGRACEAE N~rnorlterubieririis SP, SB CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN EEI) MORTALITY

Treatments Soi1 surface seed predution expehent 6 experimental plots, each rneasuring 1.5 m x 6.5 m were established in July 1997, roughly in phase with the annual cycle of seed dispersal. Plots were distributed evenly dong the elevational gradient of the site but were otherwise randomly placed. Each plot contained 16 petn dishes. representing a factorial combination of 4 treatments and 4 seed combinations of 10 or 1 1 species Seed combinations were generated by randomly dividing the 43 expenmental species into 4 combinations of 10 or 11 species, using selection without replacement. 20 seeds of each of the species in a combination were placed on 1809 of dry. sterile sand in each 14 cm x 1 cm prtri dish. This process was repeated for each experimental plot.

The four treatments used were: 1) control, 2) vertebrate exclusion, 3) insect exclusion, 4) vertebrate + insect exclusion. In the control and vertebnte exclusion treatments, petri dishes were sunk into the ground leaving the edges flush with the soil surface and allowing easy access to crawling insects. Vertebrate exclusion was accomplished by enclosing the petri dish in a wire mesh cage (1 cm gauge) secured by ground staples. Insect exclusion was accomplished by covering the outer edge of the petri dish with Tangle-trap Insect Trap Coating (The Tanglefoot Company, Grand Rapids, MI, USA) and leaving the petri dish on the soil surface.

The contents of the petri dishes were recovered in August 1997, after a month in the field. New seedlings of the study species which were present in or imrnediately around the petri dishes were recorded at the time of seed recovery. Seeds were separated from the rest of the petn dish contents in the lab with a 0.5 mm sieve, which caught most seeds while letting the sand through. The sünd wüs weighed to provide an independent measure of loss of dish contents due to wind, min or handling. Very small seeds which passed through the sieve, and any other undrtected seeds were deiected by incubating samples in the greenhouse. The sand from each petri dish was spread thinly (ca. 0.25 cm) over potting mix in a 12 cm x 20 cm tray and was kept moist for 3 months under an automatic sprinkler system. Seedlings were recorded after 1.5 months and at 3 months. Seeds were recorded as recovered if seedlings were detected in the field, if seeds were found in the lab after sieving the recovered sand, or if seedlings were recorded in the recovered sand in the greenhouse. Petri dishes from the insect exclusion treatments were carefully examined for seeds which had become stuck in the Tangle-trap coating. These seeds were excluded from the analyses. CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Seed bank mortality experiment 18 experimental plots, 1.5 m x 1.5 m in area, were established in June 1997. Plots were distnbuted evenly alorig the elevational gradient of the site but were otherwise randornly positioned. Plots contained 16 small, thin walled peat pots (4 cm x 4 cm x 5 cm depth) filled with a mixture of seeds and 20 cm3 of local field soil (collected immediately preceding the establishment of the experiment). The peat pots had 2 cm x 3 cm holes cut in the lower half of each side and the upper 1 cm removed from one side, in order to allow access by soil biota. A 4 mm drainage hole was also added in the bottom of the pots. These pots were buried just below the soil surface and allowed to incubate under field conditions. The 16 peat pots represented a factorial combination of 4 treatments and 4 seed combinations of 9 or 10 of the 29 experimental species. Seed combinations were randomly generated as described above. Each peat pot contüined 20 seeds of each of the species in that combination. Neutra1 markers (20 glass beüds) were also added to each peat pot in order to provide an independent measure of seed recovery. Quantification of the pre-existing seed bank in the soi1 revealed that seeds of some of the experimental species were present, but that the pre-existing seed density of rnost of these species was very small relative to the density of added seeds (Chapter 2).

The four treatments used were: 1) controi, 2) fungicide addition, 3) insect exclusion. 4) fungicide addition + insect exclusion. For the fungicide addition treatment, 5 ml of a fungicide solution was added to the soil and seed mix immediately before burial, with identical doses added in the field by syringe in October 1997, May 1998 and September 1998. The fungicide solution was a 1: 100 solution of a commercial fungicide in water (Maestro 75DF, Zrneca Corp., Stoney Creek, ON, Canada, active ingredient 75% Captan by weight). This concentration was recommended by the manufacturer for use as a dip for bulbs and iubers. Captan is a non-systemic heterocyclic nitrogen fungicide used against a wide range of fungi in the Oomycota, Ascomycota and Basidiomycotina (S harvelle 196 1. Torgeson 1969. Neergaard 1977) and is noted as being particularly effective against seed-rotting organisms (Neergaard 1977). If has been shown to have minimal effects on endomycorrhizal fungi and both positive and negative effects on ectomycorrhizae development (Vyas 1988), depending on plant species.

Insect exclusion was accomplished by drying soil at 50°C for 48 hours and enclosure of the peat pot in 1 mm nylon window screening to restrict access by soil fauna The processes of collecting the soi1 and ueating it undoubtedly reduced both invertebrates and soil fungi in al1 treatments; the purpose of the invertebrate and fungus exclusion treatments was primarily to restrict the recolonization of these organisms. ÇHAPTER 3: EXPERIMENTAL SURVEY OF NATWE AND ALIEN SEED MORTALITY

Six plots each were randornly setected for retneval in November 1997, June 1998 and October 1998 (hereafter called the 4 rnonth, 1 i month and 16 month trials). Peat pots were carefully dug up with their contents intact, and the plants growing out of the peat pots were recorded. After recovery, the soil and seeds were spread thinly (field soil depth approximately 0.5 cm) over potting mix in 15 cm diarneter pots. Pots were kept moist for three months in a greenhouse and seedlings were recorded monthly until the end of the germination penod. After 1.5 months, the layer of field soi1 was disturbed to allow buned seeds a better chance at germination. After the germination penod, the field soil was removed frorn the greenhouse pots and was passed through a 1 mm sieve to recover glass beads. Seeds were recorded as recovered if they were found as seedlings in the peat pots in the field, or if they were recorded as seedlings in the greenhouse.

Analysis Data for the seed predation experiment and for each of the three trials of the seed bank experiment were analyzed similarly. Recovery rates (R) were first corrected for physical losses of seeds. For the seed predation expenment, sand recovery was used as a measure of physical losses by the formula: ,,,,,, R,,,,,, - R ,,,,, / (proportion of sand recovered).

For the seed bank mortality experiment, the recovery by greenhouse germination was corrected but the recovery by field germination was not, as it was considered independent of soil losses during sampling. The formula used was: - Rcomcted - Rgcrmrnïie

The corrected seed recovery prrcentages were arcsin trünsformed to improve normality (Kirk 1982). After initial analysis of the entire data set, data were divided by ongin (native or alien) and by species for separate analyses. Analyses were 3-factor randomized block factorial ANOVAs with blocking by plot. Some values were missing due to vandalism, loss of pots, and problems distinguishing certain species when they CO-occurredin a seed combination. Of the 1032 experimental values in the seed predation experiment, 9 were missing. Of the 960 experimental values in each of the 3 trials of the seed bank experiment, 3 1.56 and 15 were missing. To restore a balanced design, missing values were replaced with the rnean of the remaining values in that treatment x species combination (Underwood 1997). The number of degrees of freedom for error was reduced by the number of durnrnied values in each analysis (Underwood 1997). For dl analyses, a non-interactive mode1 was used, as recommended by Newman, Bergelson and Grafen (1997). Thus, treatment was treated as a fixed effect, plot was treated as a random blocking factor, and the residuai was used as the error terrn. Finally, in order PERlMENTAL SURVEY OF NATWE AND ALIEN SEED MORTAIJTY

Results Soil surface seed predation experiment Overall uncorrected seed recovery rate was 37.46%IQ. 13% (al1 values are mean~SEM)and overdl sand recovery was 89.5 1 %%iû.90%, resulting in a corrected recovery rate of 41.37%*0.98%. Most seed recovery (3 1.86% of seeds) was accomplished by sieving; 2.73% of seeds germinated in the field, 0.95% of seeds were recovered outside of petri dishes in the field and 1.858 of seeds germinated after greenhouse incubation. Recovery rates varied substantially between species (Table 3.2). with corrected rates varying from 85.45% in Aiternone cyhdricn to 3.96% in Verbascuni tliapsus. As would be expected, recovery by greenhouse germination tended to decrease as recovery by sieving increased. Five native species, Solidago nemoralis. Arabis glabra, Penstemon hirsutus. Poten tilln argutn and Artenresia campestris and one exotic. Verboscum thapsm, were recorded primarily or entirely by greenhouse germination. These were al1 small seeded species, for which overall recovery was low. Of the ten species with the lowest recovery rates, five were recorded mainly or entirely through greenhouse germination. The reduced recovery associated with the small seeded species is not considered a major bias since the main purpose of the experiment was to make cornpansons within species for examination of treatment effects. The magnitude of seed removal by seed predators, as measured by the difference between exclusion and non-exclusion treatments, was considerably lower than that found in most previous studies. 1 found that excluding vertebrates increased overall seed recovery by only 8.3% over one month, although increases by species ranged up to 46.4% (Table 32). The overall effect of invertebrate exclusion was negligible, although there were species for which invertebnte exclusion both increased and decreased recovery substantially (Table 3.2).

Seed recovery was spatially variable, with plot having a highly significant effect (Table 3.3). The vertebrate exclusion treatment resulted in a 10.7% increase in seed recovery rate, which was highly significant (Table 3.3). Effects of vertebrate exclusion varied significantly between species (Tables 3.2, 3.3). Contrasts indicated that effects of vertebrate exclusion were positive for 32 of the 43 expenmental species (Table 3.4). Insect exclusion had no effect overall (Table 3.3, Figure 3.1), but insect exclusion x species interactions were significant (Tables 3.2, 3.3). Seed recovery was increased as a result of insect exclusion in only 20 of the 43 species (Tables 3.4). ,WEEDMORTALITY

Table 3.2. Results of seed predation experiment: Mean proportional seed recovery * SEM (n=6 repiicates per species. per treatment. unless otherwise noted in brackets after SEM), by treatment and species. Recovery percentages are corrected for physical losses. Native species are indicated by "N", and alien species are indicated by "A".

Species Control Invertebrate Verte braie Invertebrate exclusion exclusion & vertebrate

*A lyssunr a lysnides *;ltiemo~tecylindrica rubis glabra "Arctiuni minus

N~ rtentisia campestris NAsclepiasqriacu ~ronirtskalniii

"Bromus tecronrm NCarexmuhlertbergii "Cu rex spicata "Cherrupodium nlbuni "CCtrysanrheniunt leuca~ithenium "Daucus carota "De.vmodium catiadense *Digitaria ischaemrrni ADipsacrrssylvestris "Echiunt iulgarr "Qwtus repens NEly~rtustrachycaulits NGeumcileppicum 9R. ALIEN SEED MORTALITY

Table 3.2. Continued. Species Control Invertebrate Vcttebrate Invertebrate exclusion exclusion & vertebriite - exclusion "Geuni urbununt 0.6 l4I0.08 1 (5) 0.75 1 iO.075 (5) "Huckelia virgiriiarta Hedeoma hispida AIRonuruscardicrca NLespede:a capitata *Melilotus alba "Moriardafistulosa ANepeta cararia "Oeriothera biennis NPanicumlirrearifnl iunr Perisrenlon hirsutlrs *Plurztago major ~lmragorrcgellii "~oterzrillaarguta *Potrtitilla recru "Ruriunculus rlraniboideits "Runiex crispus "~ilrrieantirrhirra Asilerie vulgaris NSnlidagonemoralis "Sorghasrncm nutans AVerbascumrhapsus "Vicia cracca ÇHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALlTY

Table 3.3. Results of 3-factor randomized block factorial ANOVAs on overall. native and dien data from seed predation experiment. Treatment was treated as a fixed effect, plot was treated ris ii mndom effect and the rcsidud wasusedas theerror ten. * =Pc0.01, **= P~0.001,*** =Pc0.0001

SEED PREDATlON EXPERIMENT - OVERALL ANOVA TABLE Factor d f MS F-vol ue plot 5 1.698 7.490*** venebrate exclusion I 12.201 53.822*** insect exclusion 1 0.000 0.000 species 32 1 0.563 46.596*** vertebrate exclusion x insect exclusion 1 0.460 2.029 vertebrate exclusion x species 42 0.537 2.413*** insect exclusion x species 42 0.412 1.817** venebrrite exclusion x species 32 0.256 1.129 errorl 846 0.227 'degrees of freedom for error (= 855 - 9) adjusted for 9 dummied values (Underwoc~d1997); see methods.

SEED PREDATION EXPERIMENT - NATIVE ANOVA TABLE Fac cor d f MS F-value plot 5 0.733 3.4 12** vertebrrite exclusion I 6.947 32.336*** insect exclusion 1 0.038 O. 177 species 2 1 13.50 1 62.833*** vertebrate exclusion x insect exclusion 1 1.330 6.191* vertebrate exclusion x species 2 1 0.666 3.100*** insect exclusion x species 2 1 0.444 2.067** vertebrate exclusion x species 21 0.243 1.131 error' 331 0.215 'degrees of freedom for error (= 43 1 - 4) adjusted for 4 dummied values (Undenvood 1997); see methods. UPTE.AR3, SEED ATTVEORTALlTY

Table 3.3. Continued

SEED PREDATION EXPENMENT - AMEN ANOVA TABLE Factor d f MS F-value

plot 5 1.131 4.713*** vertebrate exclusion 1 5.335 22.232*** insect exclusion 1 0.033 O. 138 species 20 7.844 32.688*** vertebrate exclusion x insect exclusion I 0.030 O. 167 vertebrrite exclusion x species 20 0.333 1.846* insect exclusion x species 20 0.393 1.638* vertebrate exclusion x species 20 0.240 1.000 crrorl 410 0.230

'degrees of freedom for error (= 4 15 - 5) adjusted for 5 dummied values (Undewood 1997); see methods. CHAPTER 3: EXPEUMENTAL SURVEY OF NATNE AND ALIEN SEED MORTALITY

Table 3.4. Seed predation expenrnent; vertebrate exclosure (V.E.)and invertebrate exclosure (LE.) effects on seed recovery by species, with seed weights. Effect sizes are listed from largest to smallest for V.E and I.E. Seed weights represent weights of seeds as used in experirnent (one seed plus any accessory structures naturally with seed at time of dispersal).

= (meanvcncbmtc cxc~usion+ meaninvcnehnte and vcrtcbmtccxclusion) / (meanconcd + meaninvcttcbmtc CXC~II,~..) IeE* = (meaninwnebna exchwion + meminrcncbnie ;uid rcncbncc cielusion) '(meanconmi + meanvettcb~,~ cxcî~s~on)

V.E. (5%) Species I.E. (%) Species

Elyntus trach~caulus Dipsacus sjlvestris Sorghastrum riutarts Chrysaritheniuni leucarztliemuni Rariitriculits rliomboidetcs Elymus t racltycnulus Elyntrcs repens Desniodiuni cariadense Echiuni viclgare A nemisia cnnzpestris Pariicitni liriearifoliuni Plan rago major Rurriex crispus Digitaria ischaemurn Carex spicara Anenlotte cyliridrica Plantago rugellii Siletie antirrhina Dipsacus qlvestris Parlicicni liriea rifol ium Daitcics carom Dortcus caruta Asclepias sjriaca Ranuticrt lus rlzonilzoideus Vicia cracca Hedeoma hispidu Bronilu rectoruni Arcthni minus Clietropodium albuni A lyssum alysoidrs Potentilla arguta Hackelia virginiana Siletze idgaris Geum urbanum Oenothera bienriis Solidago nenioralis Digitaria ischaemum Melilotus alba Brumirs kalmii Bronlus recto runl Carex ntuhlenbergii Carex spicata Solidago nemuralis Elymus repens Leorrurus cardiaca Oenothera biennis Silene antirrhina Echium vulgare Ce .E EED T

Table 3.4. Continued

V.E. (%) Species seed wt. LE. (5%) Species seed wt. (mg) A rcriunt nzitws Leoriunrs cardiaca A rreniisia canrpestris Nepera cnîariu Hnckelia virgitiiana Silerie rulgaris Melilotus alba Lespede:a capiraia Desntodiutn cariadettse Planraga rugellii Hedmnia hispidn Asclepias syriaca Geum aleppicunt Geitni aleppicuni Ceuni rrrbntium Ambis glahra A lyssuni al~soides Sorgliastrtrnl rturans Atientorie cylirtdrica Brnmus kalniii Motlarda fistrc iosa Vicia cracca Chtysurrilten~untleucunrhemum Camr nllrhletiber,qii Lespede:~capitara Ver6ascunr rltapsus Nrperu c-ataria Chettopadiiini albunt Porentilkr recra Porerlîilla recru Plunrago major Porenrilln argiira A rahis glabra Moriurda fisridosa Perlsrertlort hirsutits Perrsrerrlott Iiir=riirus Vrrbascrinr rhapsus Rutnex crispus CHAPTER 3; EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Wiien analyzed separately. the general pattern of treatment effects did not differ substantially between natives and aliens (Table 3.3). Irrespective of origin. plot and species had highly significant effects on seed recovery (Table 3.3). For both natives and aliens, vertebnte exclusion had a highly significant positive effect on seed recovery and there were significant interactions of insect exclusion x species and vertebrate exclusion x species (Table 3.3). The rnost substantial difference with respect to origin was the presence of a significant vertebrate exclusion x insect exclusion interaction in natives but not in aliens.

Seed bank mortality experiment Seed recovery. as measured by seedlings counted in the field plus seedlings counted in the greenhouse. vûried substantially between trials (Figures 3.2-3.4). In the 4 month trial 2 1.7% of seeds were recovered. This proportion was adjusted to 24.9% after correction for mechanical losses. as measured by the proportion of glass beads recovered. Rccovery peaked in the 1 1 rnonth trial at 28.7%. corrected to 32.1% recovery. The lowest recovery rates were from the 16 month trial. retrieved in faIl 1998, with an uncorrected rate of 14.9% and a corrected recovery rate of 16.6% of seeds. Rates of bead recovery remained almost constant through the three successive trials at 87.4%. 87.01 and 88.4%, strongly suggesting that differences in seed recovery between the trials were not due to differing levels of mechanical loss. The relative importance of field and greenhouse recovery chünged over the three trials. The increase in recovery betwern the 4 month and 1 1 month trials resulted from an increase in seedlings in the greenhouse rather than in the field, while in 16 month trial, reduced recovery was a result of reductions in both field and green house germination (Table 3.5). Figure 3.1. Overall results of the above-ground seed predation expenment: Proportion of seed recovered in controls and predator exclusion treatments + SEM.

insect vertebrate vertebrate + insect exclusion exclusion exclusion

Treatment

Table 3.5. Proportions of total seeds in each trial recovered as seedlings in the field and by germination in the greenhouse in the seed bank expenment.

Trial Proportion Proportion length Field Greenhouse

4 month 0.067 O. 149 11 month 0.068 0.219 16 month 0.036 0.1 12 CHAPTER 3: EXPERIMENTAL SLJRVEY OF NATiVE AND ALIEN SEED MORTAI ITY

Native and dien species responded very similarly to the treatments with no consistent differences between the three trials (Tables 3.6-3.8; Figures 3.2-3.4). Recovery rates by species were not significantly different between natives and aliens in any of the three trials (means: 4 month trial, native - 26.5%. alien - 22.5%; 11 month trial, native - 35.4%. alien - 29.8%, 16 month trial, native - 17.5 %, aIien - 15.4%). Responses to the treatrnents were similar in direction for natives and aliens. with sonle differences in strenpth of treatment effects. Fungicide significantly increased overall seed recovery in al1 trials while invertebrate exclusion did not produce any significant effects on overall seed recovery (Tables 3.6-3.8). In the 1 1 month trial however, invertebrate exclusion resulted in a rnarginally significant increaïe in seed recovery (P=0.06).The strength of the overall fungicide effect was greatest in the four rnonth trial. in which fungicide significantly increased recovery of both native and alien species when those species were analyzed as separate groups. In the 1 1 month and the 16 month trials, although fungicide significantly increased overall recovery, on1y the alien and not the native species exhibited significant fungicide effects. The overall fungicide x species interaction was significant in the 16 month trial. and significant fungicide x species interactions were also found for natives in the four month trial and for alien species in the 16 month trial. In the II month trial there was a significant overall invertebrate exclusion x species effect. Recovery varied significantly with plot in the 4 month and 16 month trials, but not in the 11 month trial. In the four month trial fungicide improved recovery for 23 of the 39 experimental species. relative to the controls. and invertebrate exclusion improved recovery for 17 (Table 3.9). In the 1 1 month trial fungicide irnproved recovery for 22 species and invertebrate exclusion for 24 species (Table 3. IO), and in the 16 month trial, recovery was respectively improved for 24 and 16 species.

Variation in recovery rates by species were highly significant in each trial (Tables 3.6-3.8). Lrsprdeia capitnta had the lowest recovery rates in al1 three trials at less than 1 %. Maximum species recovery rates wcre 61.4% in the four month trial for Elynrus traclzycnuius, 77.7% in the 11 month trial for Ritmex crispus and 53.5% in the 16 month trial for Rumex crispus (Tables 3.9- 3.1 1 ). Patterns of recovery in legumes and grasses were distinct from the rest of the experimental species. Legumes. except Vicia crctcca in the 1 1 month trial, were recovered at very low rates and al1 grass species were recovered largely as seedlings in the field, with five of six species showing maximal recovery in the 4 month trial with declining recovery through the 1 1 and 16 month trials. CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.6. Results of 3-factor randomized block factorial ANOVAs on overall data (native + alien). native dmand alien data for 4 rnonth trial of the seed bank experiment. Treatment was treated as a fixed effect, plot watreated ris a random effect and the residual was used ris the error term. * =P

SEED BANK EXPERIMENT - FOUR MONTH TRIAL - OVERALL ANOVA TABLE Factor d f MS F-value Plot 5 0.422 2.433* fungicide 1 3.122 18.Oo2*** invertebrate exclusion 1 0.031 O. 179 species 38 6.896 39.764*** fungicide x invenebrate exclusion 1 0.059 0.310 fungicide x species 38 0.236 1.361 invenebrate exclusion x species 38 O. 164 0.946 fungicide x invertebratc exclusion x species 38 0.198 1.142 error ' 74-4 0.173 'degrees of freedom for error (=775-3 1 ) adjusted for 3 1 dummied values (Underwood 1997): see methods.

SEED BANK EXPERIMENT - FOUR MONTH TRIAL - NATIVE ANOVA TABLE Frtc tor d f MS F-value Plot 5 0.348 1.850 fungicide 1 2.826 15.025*** invertebrate exclusion 1 0.293 1.563 species 18 7.253 38.562*** fungicide x invertebrate exclusion 1 O. 106 0.563 î'ungicide x species 18 0.305 1.621 * invertebrate exclusion x species 18 O. 160 0.851 fungicide x invertebrate exclusion x species 18 0.121 0.643 error' 360 0.188 'degrees of freedom for error (=375-15) adjusted for 15 dummied values (Underwood 1997); see methods. CHAPTER 3: EXPERIMENTAL SURVEY OF NATNE AND ALlEN SEED MORTALITY

Table 3.6. Continued

SEED BANK EXPERiMENT - FOUR MONTH TRIAL - ALIEN ANOVA TABLE Factor d f MS F-value Plot 5 0.326 2.057 fungicide 1 0.687 1.336* i nvertebrate exclusion 1 0.079 0.499 species 19 6.783 42.813*** fungicide x invenebrate exclusion 1 0.430 2.713 fungicide x species 19 O. 163 1 .O29 invertebrate exclusion x species 19 O. 158 0.997 fungicide x invencbrate exclilsion x species 19 0.256 1.6 16* errnr' 379 0.158 'deprees of freedom for error (=395-16) ridjusted for 16 durnmied values (Undewood 1997); see mrthods. CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.7. Results of 3-factor randomized block factorial ANOVAs on overall data (native + alien), native data and alien data for the 1 I month uial of the seed bank experiment. Treatment was treated as a tïxed effect. plot wris treated as a mndom effect and the residual was used as the error term. *=P

SEED BANK EXPERIMENT - 1 1 MONTH TRIAL - OVERALL ANOVA TABLE Factor df MS F-value Plot 5 0.313 1.495 fungicide I 1.1 12 5.311* invertebrate exclusion 1 0.773 3.692 species 38 6.909 33.W 1 *** funpicide x invertebrate exclusion 1 0.437 2.087 fungicide x species 38 0.224 1.070 invertebrate exclusion x species 38 0.292 1.395 fungicidr x invertebrate rr;clusion x species 38 0.2 15 1.027 error ' 719 0.209 'degrees of freedom for error (=775-56) adjusted for 56 dummied values (Underwood 1997); see methods.

SEED BANK EXPERIMENT - 1 I MONTH TRIAL - NATIVE ANOVA TABLE Factor d f MS F-value Plot 5 0.262 1.096 fungicide 1 0.086 0.360 invertebrate exclusion 1 0.589 2.163 spec ies 18 8.675 36.279*** fungicide x invertebrate exclusion 1 0.323 1.351 fungicide x specirs 18 0.272 1.138 invertebrate exdusion x species 18 0.313 1.309 fungicide x invertebrate exclusion x species 18 O. 193 0.807 error' 345 0.229 'degrees of freedom for error (=375-30) adjusted for 30 dummied values (Underwood 1997); see methods. CHAPTER 3: EXPERIMENTAL SURVEY OF NATNE AND ALEN SEED MORTALITY

Table 3.7. Continued

SEED BANK EXPERIMENT - 1 1 MONTH TRIAL - ALLEN ANOVA TABLE Fac cor d f MS F-value Plot 5 0.141 0.768 fungicide 1 1.407 7.683** invertebrate exclusion 1 0.230 1.256 species 19 5.463 29.827*** fungicide x invertebrate exclusion I O. 136 0.743 fungicide x species 19 O. 170 0.930 invertebrate exclusion x specics 19 0.284 1.551 fungicide x invertebrrite exclusion x species 19 0.236 1.342 error' 369 0.210 'degrees of freedom for error (=375-26) adjusted for 26 dummied values (Underwood 1997); see methods. CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALEN SEED MORTALITY

Table 3.11. Results of 3-factor randomized block frictorial ANOVAs on overall data (native + dien). native data and alirn data for the 14 montb tria1 of the of seed bank cxperiment. Treatment wrts treatcd ris a fixed effect. plot wris trecited as a nndom effect and the residual was used ris the error term. * = P < 0.01, ** = P < O.Oo!, *** = P c 0.0001

SEED BANK EXPERIMENT - 14 MONTH TRJAL - OVERALL ANOVA TABLE Factor d f MS F-val ue Plot 5 1.69 1 8.350* ** fungicide 1 1.156 5.776* invertebrate exclusion 1 0.052 0.260 species 38 3.066 20.3 17*** fungicide x invertebrate exclusion 1 0.023 0.1 15 fungicide x species 38 0.306 1.529* invenebrate exclusion x species 38 0.139 0.745 fungicide x invertebrate exclusion x species 38 O. 149 0.735 errorl 759 0.200 'degrces of freedom for error (=775- 16) adjusteci for 16 dummied values (Underwood 1997); see methods.

SEED BANK EXPERIMENT - 14 MONTH TRIAL - NATIVE ANOVA TABLE Factor d f MS F-val ue Plot 5 1.265 5.474*** fungicide 1 0.267 1.155 invertebratr exclusion 1 0.004 0.01 7 species 18 5.111 22.118*** fungicide x invertebrate exclusion 1 0.034 O. 147 fungicide x species 18 0.253 1.095 invertebrate exclusion x species 18 0.181 0.783 fungicide x invertebrate exclusion x species 18 0.2 15 0.930 error ' 370 0.231 'degrees of freedom for error (=375-5) adjusted for 5 dummied values (Underwood 1997); see methods. CWAPTER 3: EXPERIMENTAL SURVEY OF NATWE AND ALEN SEED MORTALITY

Table 3.8. Continued

SEED BANK EXPERIMENT - 14 MONTH TRIAL - ALIEN ANOVA TABLE Factor df MS F-value Plot 5 0.72 1 3.264*** fungicide 1 0.995 5.885* invertebrite exclusion 1 0.066 0.390 species 19 3.289 19.453* fungicide x invertebrate exclusion ! 0.001 0.006 fungicide x species 19 0.366 2.165** invertebrrite exclusion x species 19 0.125 0.739 fungicide x invrrtebrate exclusion x species 19 0.094 0.556 error ' 381 0.169 'degrees of freedom for error (=395- 1 1 ) ridjusted for 1 1 dummied values (Underwood 1997);set: niethods. Figure 3.2. Results of the four month trial of the seed bank expriment, by method of recovery (germination in field and germination in greenhouse). Proportion of seeds recovered are corrected for physical losses. Results (mean +SEM)are given for al1 species, for native species only and for aiien species only.

0.3

ORS -hW OP 0 p*mh*.dhgnrihouu 0.15 a-- 0.1 0.05 O ÇHAPTER 3: EXPERIMENTAL SURVEY OF NATiVE AND ALlEN SEED MORTALITY

Figure 3.3. Results of the 1 I month trial of the seed bank experiment. by method of recovery (germination in field and germination in greenhouse). Proportion of seeds recovered are correcied for physical losses. Results (mean +SEM) are given for al1 species, for native species only and for alien species only. Figure 3.4. Results of the 16 month trial of the seed bank experiment, by method of recovery (germination in field and germination in greenhouse). Proportion of seeds recovered are corrected for physical losses. Results (mean +SEM)are given for al1 species, for native species only and for alien species only. CHAPTER 3: EXPERIMENTAL SURVEY OF NATNE AND ALIEN SEED MORTALITY

Table 3.9. Results of four month trial of seed bank expriment: Mean percentage seed recovery corrected for soi1 losses. by treatment and species. A SEM (n=6 replicates per species. per treatmcnt. unless utherwise noted in brackets after SEM).Native species are indicated by "N", and alien species are indicated by "A".

Species Control Invertebrate Fungicide Fungicide & exclusion invenebrate

N~tzdropogongerurdii

N~ rientane cylindrica AArcrittnr niinus Y~neniesiacumpesrris 'v~sclepiassyriaca N~ster-ericoides 'YBroniuskalniii AClie~iopodiumalbum " Ctinsatithert~unr feucantheniitm AD~~~tl~carora "Desniodiuni cartadense " Dipsacus sylvestris

A Echiunz vrrlgare

A Elynzus repens 'v~lyrnicsrrachycaul us " Etysimum cheiranrhoides NGertnt aleppictcnt 'V~ackeliavirg irziarta AHitrrnciitmarr rtltiriacum NHieraciumscabrttm ALe~ri~rtc~cardiaca NLespedeza capitatcl "Medicago lupulina "Melilorus afba CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.9. Continued. Species Control Invertebnte Fungicide Fungicide & exclusion invertebrate exclusion *'Motiardafistulosn 0.332I0.069 0,328M.063 0.323I0. 1 12 0.315I0.112 ANeperacataria 0.040I0.020 0.06210.026 0.057I0.023 O. 130I0.035 "Oertothera bienriis 0.19 1 I0.060 0. 170M.039 0.32 1 I0.05 1 0.25710.055 'VPe~wremonhirsutits 0.150I0.049 0.223a.026 0.26510.066 0.288I0.057 " Phleilm pratense 0.4 1 2kO.033 (5) 0.123I0.088 (5) 0.2821t0.080 (5) 0.334a. 125

A Plattrago major 0.56210.072 (5) 0.44 1 I0.064 (1) 0.5 15d.127 (5) 0.358I0.126 (5) VPlaritago rugellii 0.556I0.0(i 1 (5) 0.462M.064 (5) 0.446I0.096 (5) 0.507I0.092 (5) 'VPoreritillaargttta 0.258d.060 0.247I0.037 (5) 0.224M.0.15 0.320I0.057 APoretirillarecta 0.035I0.022 0.02 1 I0.02 1 (5) 0.03910.025 0.06310.025 ARitrr~excrispus 0.62810.066 0.493I0,072 (5) 0.583d. 107 0.699îO.060

"Solidaga nenroralis 0.1 3710.025 0.19~I0.063 0.17410.049 0.268+0.083 "Sorghusrntnznutriris 0.348d.070 0.34210.1 03 0.32 1 Io.1 08 0.165I0.073

A Verbascttm tltapsits 0.165H.046 O. 1 1 OI0.045 O. 12210.062 O. 15510.063

" Vicia cracca O. 168I0.029 0.083a.O 17 O.OSOfl.026 0.12310.035 CHAPTER 3: EXPERTMENTAL SURVEY OF NATNE AND GLEN SEED MORTAI-ITY

Table 3.10. Results of I I month trial of seed bank experiment: Mean percentagc secd recovery corrected for soi1 losses, by treritrnent and species, * SEM (n=6 replicates per species, per treatment, unless otherwise noted in brûckets after SEM).Native species are indicated by "N', and alien species rire indicated by "A".

Species Control Invertebmte Fungicide Fungicide & exclusion invenebrate

N~tidropogongerardii "Atiernone cylindrica

A~ rctium nliws rtcnzesia canipesrris 'V~sclepiassyriaca 'V~strrericoides NBrontitskalrnii "Cheriopodiun~alliirnt

A Chnsanfhemim leucanthenium ADaucuscarotu 'V~e.sniodiirnicarrudense .'Dipsacus syl vesrris

A Echiunl vulgare

A Elyntrts repens N~iymusrrachycaulirs

A Erysimicrn cheiranrhoides "~ellniaieppicunt "~uckeliavirginiutra "Hieracirrnt aururitiacum 'VHieraciurnscabrum "Leon~rnrscardiaca N~espedezacapitara

A Medicago lupulitta "Meiilotus allia "~onardafisrulosa ÇHAPTER 3: EXPERIMENTAL SI JRVEY OF NATIVE AND ALEN SEED MORTAJ .ITY

Table 3.10. Continued. Species Con trol Invertebrate Fungicide Fungicide & exclusion invertebrate exci usion Nepeta ruta ria 0.265I0.070 O. 139I0.029 0.089d.048 0.277iû.025 "Omorhera bienriis 0.707Io. 125 (5) 0.79OM.MO (5) 0.689îû.05 1 0.579dl. 148

'VPlantagorugellii 0.763M. 1 19 (4) 0.603dI.2 12 (4) 0.799I0.075 (4) O.808îû.094 (3) NPoretitillaarguta 0.234d.028 0.354fl.030 (5) 0.380d. 12 1 O. 1 70I0.049

A Potentifla recta O. 1 1 1 I0.030 (5) O. 182I0.031 (5) 0.274H.063 0.14310.033

A Runiet crispus 0.67510.094 0.763IQ.099 (5) 0.779îû.0.19 0.88810.025 ASiletie vulgaris 0.069îû.051 0.103I0.060(5) 0.109I0.062 0.114îû.068

'V~oq/tasrrunirillrutis 0.33610.W 0.347d.W 0,36410.102 0.43010.109 (5) " Verhmcum thapsus 0.286d.072 0.137I0.075 0.376I0.083 0.539I0.074 (5)

A Vicia cracca 0.383I0.059 (5) 0.364~0.029(5) 0.360i4.037 0.350H.057 ÇHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.11. Results of 16 rnonth trial of seed bmk experiment: Mean percentage seed recovery corrected for soi1 losses, by treatment and species, * SEM (n=6 replicates pet species, per treatment. unless otherwise noted in brackets after SEM). Native species rire indicated by "N", and alien species tire indicated by "A".

Species Conuo l Invenebrrite Fungicide Fungicide & exclusion invertetinte

N~ndropogongerardii "Aliernone cylindrica "Arctirtni nrinus NArtenmia canipestris sclepias sy riclcw "Aster ericoides "~rontusknlmii AChenopodiunt alhrtm

A Ch rysanrireniirni leucari thenium A Darr cus carota NDesnindittntcanadense

A Dipsacus sylvestris

A Echium vuigare

A Ely nr us reperls "El~niirstrachyaldus

A Ensimum cheirclnthoides "Geunl aleppicunl "Hackelia virg iriiana "ieracirrm aurarrtiacunl "Hieracium scabrrtrri "Leoriurus cardiaca "Lespedeza capitora "Medicago lupulina

A Melilotus alba NMonardafistulosa CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND ALIEN SEED MORTALITY

Table 3.1 1. Continued. Species Conml Invertebnte Fungicide Fungicide & exclusion invertebrate exclusion "Nepera cararia "Oenothera bierittis 'VPensrenionhirsrrrus

A Pltierini prarerrse

A Plart rago major

'" Pinrirago riigellii "Poteririlia arguta

" Porert rilla recta * Rttniex crisplis ,'Silerie r~rrlgaris

."~oiidagori entoralis rVSorslia.~tnrnirtiitaris

A Verbascrint thapsrts

A Vicia craccu CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND AI .W.N SEED MORTALITY

Discussion Soil surface seed predation Predator idenrity Occasional droppings observed in petri dishes during the experiment indicated the presence of birds and rodents. Commonly observed seed eating birds at the study site were Field Sparrow (Spizella pusilla), Song Sparrow (Melospiza meludia), Northern Cardinal (Cardinalis cardinalis), Indigo Bunting (Passerina cynea) and Amencan Goldfinch (Cardedis tristis). Data on small mammals were not collected during the experiment, but the onIy seed eating rodents found in a subsequent srnaIl marnmal trapping program in old fields on site were Meadow Vole (Microtus pensylvanicus), deer mouse spp. (Perornyscus spp.) and Meadow Jumping-mouse (Zupirs hudsonius) (P.M. Kotanen, unpublished data). These species are ubiquitous in old field and forest edge habitats in southern Ontario (Mark Engstrom, R.O.M.,pers. corn.) and are presumed to have been the important rodent seed predators during the study. A single observation of ants removing seeds was also made, but no attempt was made to identify ants to species. The common occurrence of droppings, seed husks and damaged seeds in dishes suggests that many seeds were consumed by birds and rodents on site rather than being criched, as was found in a similar study in old field habitats (Mittelbach and Gross 1984). Likewise, seeds removed by ants are presurned to have been consurned. None of the seeds used in the study had eliasomes, thus any seed removal by ants was likely for consumption of the seed itself.

Field observations shed some light on the presence and behaviour of other invertebrate seed predators, but their roles remain unclear. Other studies show that earthworms (McRill and Sagar 1973, Grant 1983 and Thompson et al. 1994)-slugs and snaiis (Newell 1967), Carabid (Kjellson 1985) and Bruchid (Janzen 1975) beetles and Lygaeid bugs (Collins and Uno 1985) can feed on seeds at the soi1 surface. During wet periods. the slime of earthworrns, snails and slugs may have enabled them to overcome the Tangletrap barrier. In a separate study at the same location, slugs were observed to occasionally crawl ont0 and eat Tangletrap-coated seed tnp papers, without becoming entangled. Lygaeids and Carabids were likely not important post-dispersai seed predators at the site as none were found among the many insects stuck to the Tangletrap-coated dishes. If these taxa were present in the study area, they would likely have been deterred by the Tangletrap barriers, as they forage on the ground rather than in flight (Kjellson 1985).

Overnll seed rernoval The magnitude of seed removal by seed predators, as measured by the difference between exclusion and non-exclusion treatments, was considerably lower than that found in most çH_AeTERLEXPERlMENTALEN SEESEED MORTALITY previous studies. It is not surprising that predation rates were Iower than those found in studies in arid landscapes. North American and Old World deserts have numerous specialist granivore taxa, especially rodents and ants, whereas in northeastern North Arnerica, çranivorous ants, rodents and birds are generalists which rnay switch to other food sources in the summer (Mittelbach and Gross 1984,and references therein). 1 found that excluding vertebrates increased overnll seed recovery by only 8.3% over one month, although increases by species ranged up to 46.4%. The overall effect of insect exclusion was negligible. Mittelbach and Gross (1984) and Hulme ( 1994) investigated post-dispersal seed predation in oid fields in Michigan and England. They found predation rates of 5% / d and 24% 1 d over 6 d and 3 d respectively, on seeds of a range of sizes. The lower rates in my study are probably at least partly attributable to the use of a broad range of seed sizes, including nurnerous seeds weighing < 1 mg (Table 3.4), as other studies have shown seeds of this size to have lower risk of predation (Kelrick er al. 1986, Mittelbach and Gross 1984 and Reader 1993).

Another potentially important factor was the > 50% of seeds which were not recovered due to factors other than seed predators. Seeds lost to the study could not be counted as having been consumed, even if they were. The corrected rate of seed loss was 54% for dishes protected from both vertebrates and invertebrates, which theoretically should have lost no seed. Several factors were likely important in limiting recovery. First, incomplete germination as a result of dormant or inviable seeds undoubtedly lirnited the recorded recovery rates of small seeded species for which greenhouse germination was the main source of recovery. Most of these species had recovery rates well below the overall average. The magnitude of this effect is hard to determine. Most species had high germination rates (s75%)before the study, but some were significantly lower. Secondly, the correction factor for physical loss of seeds büsed on the recovery of sand from each dish was probably an underestimate. Despite the drainage holes, sand and seeds were observed to have overfiowed from some plates after heavy rains. Seeds were placed on the sand surface, and it seems likely that the proportion of seeds washed or blown out of the dishes might exceed that of the sand as a result. Field observations do suggest that although the correction factor may not have been large enough, it was in the right direction, as sand loss and seed loss tended to be correlated. Field germination and subsequent death rnay have been an important source of seed loss for a few species. There were some heavy dnsearly in the experirnent which stimulated germination for some species, followed by dry periods which desiccated the sand in the petri dishes entirely, killing some seedlings. Dead seedlings were counted as king recovered, but small seeded species which germinated and quickly died could easily have been missed. Finally, there rnay have been some predation by slugs, mails or other invertebrates which were able to get around the invertebrate barrier, as described above. These factors only limit the utility CHAPTER 3: EXPERIMENTAL SURVEY OF NATTVE AND At.IEN SEED MORTAIJTY

of the observed absolute rates of seed loss as estimators of natural predation rates. They do not significantly affect conclusions about the relative importance of different experimental treatments.

The presence of a large negative effect of insect exclusion on seed recovery for species such as Bromus kalmii, Rumex crispus and Verbascuin thapsus is hard to explain. The negative effect on Verbascu~ntlrapsus could be explained by a failure to detect the species' very smal1 seeds if they became trapped in the Tangletrap insect barrier. This explanation would not apply to Bror~rus kalnrii and Rumex crispiis. as their large seeds were easily detected when trapped in the insect brimer.

Patterns in treatmerzt efSects As shown by the significant insect exclusion x species and vertebrate exclusion x species interactions, different species of seeds are subject to different types of predators at the soi1 sudace. Larger seeds were distinctly more susceptible to vertebrate predation. Nine of the ten species of seeds with the greatest increases in recovery as a result of vertebrate exclusion had seed weights above the median of 1.O mg (P=O.OO 1, one sided sign test). This result agrees wel1 with work in shmb steppe by Kelrick et al. (1986), and in old fields by Mittelbach and Gross (1984) and Reader (1993), who found reduced rodent predation on seeds under 2 or 3 mg. Contrary to the trend in multi-species seed dish experiments (Thompson 1987). there was no consistent evidence of selectivity on the basis of seed size by insect seed predators, although the two species for which insect predation was significant (Dipsacus sylvestris and Desmodi~rni canadense) were relatively large seeded.

The Mittelbach and Gross (1984) and Reader (1993) papers used a nurnber of the same species as were in this study and found some different results. Most differences were significant predation effects found by the other authors, but not in this experiment (Daucus carota in both studies, Chrysanthemum leucanthemurn in Reader). Mittelbach and Gross, however, also found that ants (which were significant predators of other species in their study) were not significant seed predators of Dipsacus sylvestris, while my work found Dipsacus sylvestris to have the highest level of insect predation of any species. My results were in accord with iheirs for Oenothera biennis, Echiurn vulgare and Verbascurn thapsus. In addition, work by Reader and Beisner (1991) at the same site as Reader (1993) found that an&, but not rodents or birds, were significant seed predators, contrary to the findings of my experiment. My results differ from Reader's despite the fact that the sites are very similar in vegetation and only 75 km apart. CHAPTER 3: EXPERJMENTAI. SURVEY OF NATlVE AND ALIEN SEED MORTALlTY

One major taxonornic trend in predation rates was evident. Grarninoids were overrepresented among the favoured seeds for vertebrates. The six species showing significantly increased recovery with vertebrate exclusion included four grasses and one sedge, out of only 9 grarninoids in the study. This probably is related to the relatively large size of the experimental graminoid seeds and likely reflects their comparatively high quality as food items as well.

Seed bank rnorîality Fung icide addition My results demonstrate the genenl importance of fungal mortality in the seed bank and seedling stages. Overall recovery was significantly improved with fungicide addition in al1 three trials. Fungal effects on seeds and seedlings are well known in agricultural systems, as demonstrated by the extensive use of fungicide seed coatings (Taylor and Harman 1990) and foliar treatments on seedlings (Kendrick 1992). Fungal pathogens have also been shown to be important causes of seed and seedling mortality in natural vegetation. Crist and Fnese (1993) found seed decomposition rates of 0-93.5% over 10 months in seeds of six shrub-steppe species and their isolation of seven species of Ascornycete fungi from inside the seeds suggested fungal involvement. Lonsdale ( 1993) experimentally excluded higher fungi (but not Oomycota) and found 10% CO 16% increases in seed survival over 7 months for the shmb Mimosa pigrn in tropical Australia. Augspurger and Kelly ( 1984) demonstrated that darnping-off disease killed O- 958 of seedlings of 18 tropical tree species and that mortality increased with seedling density, shade and proximity to the parent tree. As well as decomposition, infection by soil fungi has been shown, in some species, to inhibit germination without immediately killing the seed (Kirkpatrick and Bazzaz 1979). to contribute to breaking dormancy of hard seeded species (Gogue and Emino 1979). to reduce colonization of subsequent microbes and to reduce or increase seed consumption by animals (Roy and Abney 1977, Janzen 1977, Crist and Friese 1993). Thus the effects of fungicide addition can be complicated and the observed results may be a combination of several effects in addition to fungal mortality. The results do indicate, however. that the combined effect of excluding fungi is increased seed survival.

The particular fungi involved in seed decomposition in soil are very poorly understood, but likely include species of both the primitive "protoctistan fuiigi" (especially the Division Oomycota) and the Eumycota (Divisions Zygomycota and Dikaryomycota). The Oomycota are especially important pathogens of young seedlings, with genera such as Pytlzium and Phytoptliora being the major cause of damping-off diseases and root-rots (Augsburger and Kelly 1984, Paul et al. 1989). Although both traditionally classed as fungi, these two major groups are C HAPTER 3- EnERIMENTAL SURVEY OF NATIVE AND AI.EN SEED MORTAJ,ITY now classified in separate kingdoms, with the "protoctostan fungi" allied with brown algac in the Strarnenopiles (Sogin and Patterson 1998). Due to physiological differences, few fungicides are effective against both groups (Paul et al. 1989). No assays of the fungi in treated and untreated soil were atternpted in this study but Captan is widely used in agriculture to control species of oornycetes, ascomycetes and basidiomycetes in the soil and on fruit, leaf and seed surfaces (Sharvelle 1961, Torgeson 1969, Neergaard 1977). The increases in recovery associated with fungicide addition in this experiment may well underestimate total fungal mortality, as fungitoxic effects of Captan are species specific and some pathogens may not have been controlled by the fungicide (Sharvelle 1961, Torgeson 1969, Neergaard 1977).

Lonsdale (1993), in the only other study which has used fungicide on seeds in field soil, found that addition of a benomyl fungicide, which is effective against Dikaryomycota, but not Zygornycota or Oomycota, resul ted in a 10% to 16% increase in relative survival of Mimosa pigm seeds over 7 rnonths. Lonsdale's measure of fungicide effect was relative to the control treatment [(% recovery with fungicide - % recovery without fungicide) / (% recovery without fungicide)]. The same calculation on my data gives a similar percentage increase in recovery; 1 16.2% and 18.1 % in the 4 month. 1 1 month and 16 month trials respectively. The same value calculated for each species ranged from negative effects (which were non-significant by ANOVA) to a 299% increase in recovery of Arctium minus in the 16 month trial, indicating substantial variability in species' susceptibility to fungi.

Invertebrate exclrrsiorz There was no significant overall effect of invertebrate exclusion in any trial, ihough there was a marginally non-significant increase (pd.06) in recovery and a marginally non-significant invertebrate exclusion x species interaction (P=0.06) at the 11 month trial. Of the 7 species in the three trials for which invertebrate exclusion significantly affected recovery, 5 showed increased recovery. Significant effects, as a percentagr of non-invertebrate treatments, ranged from a 66.7% decrease in recovery for Medicago lupulina in the 1 1 month trial to a 76.0% increase in recovery for Artemisia campestris in the 1 1 month trial.

The importance of mammalian seed predation below ground was probably minimal. Rodents are capable of detecting seeds below ground (Reichmann 1979, Johnson and Jorgenson 198 1), but Hulme (1990, in Crawley 1992) found that seed buriai reduced rodent predation by 90% across a wide range of species in English grasslands, and no evidence of rodent tunnelling around the pots was seen. Invertebrates were not quantified but earthworms and ants were the rnost numerous potential seed consumers noted in the pots after recovery. Neither earthworms nor ants were ÇHAPTER 3: EXPERIMENTAJ. SWVEY OF NATTVE AND ALEN SEED MORTALITY

completely excluded by the invertebrate exclusion screening, as they were occasionally observed in the screened pots, but the invertebrate exclusion treaiment probably would have reduced at least earthworm numbers by making access more difficult for them. The effects of earthworms on seeds have been relatively well studied (McRill and Sagar 1973, Grant 1983, Thompson et al. 1994). They consume large numbers of small seeds, and have been shown to selectively consume seeds within soil (Grant 1983). Consumed seeds may be killed. they may be excreted apparently unchanged, or they may survive with reduced dormancy, which can be fatal for seeds below ground. The impact of earthworms on seeds is variable. There is an obvious lirnit to the size of seeds which they can ingest and it seems unlikely that the rather small earthworms observed in the pots consumed any of the larger seeds in the study. Thompson et al. (1994) found that virtually al1 seeds in worm casts were less than 0.3 mg, while this size class represented only 20% of the soil seed bnnk ai his site. Earthworms can also be very important in seed movement within the soil. Some earthworm species will feed below ground and produce casts at the soil surface, while other species forage on the soil surface and excrete seeds underground (Thoinpson et al. 1994). Larger soil fauna such as earthworms and ground beetles can also move adhesive seeds extemally (Kjellson 1986). The few effects of invertebrates rneasured in this study could therefore include both mortality and seed movement out of the pots in the field. My results suggest that invertebrates may be an important source of below-ground seed n-iortality for some species, but that they are less important overall than are soi1 fungi.

Temporal pattern in seed recovery The changes in recovery rates over time retlect an interaction between increasing mortality and seasonal shifts in dormancy. The reduction in recovery rates between the 4 month trial and the 16 rnonth trial is likely to be a consequence of seed mortality, as seasonal dormancy effects should not greatly differ (both were retrieved in fall, 1997 and 1998 respectively). The fact that the recovery rate was substantially lower in the 4 rnonth trial (retrieved in faIl 1997) as compared to the 1 1 month trial (retrieved in spring 1998) strongly suggests that seeds were more dormant in the fa11 than in the spring. This result is not unexpected given that dormancy cycles are likely of rather general occurence among temperate zone herbs. Baskin and Baskin (1998), in their comprehensive summary of investigations of dormancy cycles, found that 79 of 95 species studied exhibited dormancy cycles. Their list of studies included references for 7 of my expenmental species. Chenopodium album (Chnstal et al. 1998), Daucus carota (Pons 199 l), Oenothera biennis (Baskin and Baskin 1994), Solidago nemoralis (Walck et al. 1997) and Verbascum rhapsus (Baskin and Baskin 1983) exhibited dormancy cycles, while Potentifla recta (Baskin and Baskin 1990) and Rurnex crispus (Baskin and Baskin 1985) were shown not to have dormmcy cycles. Changes in dormancy through the three trials and the difficulty in ÇHAPTER 3: EXPERiMENTAL SURVEY OF NAWE AND ALEN SEED MORTAJ JTY

distinguishing dead seeds from live but dormant seeds lirnits the extent to which my recovery values can be considered to represent natural rates of seed survival. This does not, however, create a problem in comparing treatment means within a species and trial. which is the primary focus of this work.

Treatment efects vs. seed size Several recent papers (Thompson et al. 1993, Bekker et al. 1998, Thompson et al. 1998) have correlated seed size with persistence in the soil for several hundred species in northwest Europe. including most of the alien species used in this study. These studies found that species with long term seed banks are generally smaller seeded. Leishman and Westoby (1998), on the other hand. found no correlation between seed size and longevity for Australian species. In my experiment, there was no evidence of srnaller seeded species having a greater resistance to fungi, as might be expected if they tended to be longer tem seed bankers. There are both small and large seeded species among those for which fungicide addition and invertebrate exclusion improved recovery. Regressions of fungicide and invertebrate effects by species vs. seed weight were non-significant for al1 three trials. with slopes generally close to O. Seed banking requires a suite of morphological and physiological characters in addition to disease resistance (Leck et al. 1989, Fenner 1985, Baskin and Baskin 1998). If a relationship between seed size and dormancy dors exist, it may be better explained by germination charactenstics than by fungal resistance.

Tuonumic paftern Severai taxonomie patterns were obvious in the data. The very low recovery rates (40%) of al1 the legumes except for Vicia crncca (Desmodium canadense, Medicago lupulina, and MeLilotus cilbu), were expected given the hard, impermeablr seed coats typical of the farnily (Baskin and Baskin 1998). Imbibition and germination in these species does not occur until the seed coat breaks down. Sieving the soil after the germination period revealed that the legume seeds were still present. In post-experiment germination tests these seeds were highly viable when the seed coats were scarified. Sirnilarly, the pattem of recovery among the grasses was quite distinct from the rernainder of the species. Al1 gras species were recovered Iargely as seedlings in the field. with that pattem especially pronounced in the aliens Elymus repens and Phleum pratense and the native Elymus rrachycaulus. Within the grasses. five of six species showed maximal recovery in the 4 month trial with declining recovery through the 11 and 16 month trials. This strongly contrasted with the forb species; al1 forbs were recovered pnmvily by greenhouse germination and 26 of 33 species reached maximum recovery rates in the 11 month trial. This pattem can be attributed to two factors. First is the tendency for grasses to have limited seed dormancy and to be less likely to produce long term seed banks than herbs (Thompson et al. 1998, Baskin and CHAPTER 3: EXPERIMENTAL SURVEY OF NATIVE AND AIEN SEED MORTALITY

Baskin 1998). Second, the relatively large seeds of most of the grasses in the study were likely important in allowifig seedlings to push through several cm of soil to the surface and survive to be counted where smaller seeded species might have perished.

Aliens vs. natives Neither experiment produced evidence that aliens benefitted from a reduced rate of seed predation. as predicted by both the predator filter and predator escape hypotheses. In the soil surface experiment. patterns in predation rates with respect to treatment. plot, seed size. and taxa were generally consistent between natives and aliens. Overall responses to insect and vertebrate exclusion were similar for natives and aliens. The only differential response with respect to origin was the presence of a significant vertebrate exclusion x insect exclusion interaction for native species. with insect exclusion producing no effect by itself, but resulting in a slight increase in seed recovery when in combination with vertebrate exclusion. For aliens, insect exclusion effects were negligible with or without vertebrate exclusion. Natives and aliens also responded similarly to soil pathogens. Where observed, di fferences between native and alien species were inconsistent between the three trials.

The predator escape hypothesis requires the existence of species specific natural enemies. In contrast. the predator filter hypothesis does not require specialist pathogens - only that successful exotics tend to be more pathogen-resistant than species that fail to establish. Most of the seed predators in this experiment probably were generalists (birds. rodents, and eanhworms). Although many fungal plant pathogens are gçneralists (von Broembsen 1993), host specitkity among seed pathogens is known in agricultural plants (Neergaard 1977, Agarwal and Sinclair 1997). and there is some evidence that natural fungal communities associated with different species of seeds Vary within the sarne habitat (Kirkpatrick and Bazzaz 1979. Harman 1983. van der Putten et al. 1993). The most likely explanation for the sirnilar responses of native and alien species in these experirnents is that both soil fungi and seed predators were sufficiently indiscriminate generalists that they did not distinguish between native and alien seeds. It is also plausible that some species specific pathogens of alien seeds have already been inadvertently introduced to the New World on seeds or in soil, or that pathogens specific to native species have become adapted to alien congeners since the mival of the aliens. In either case, the results indicate that predator escape by alien seeds is not a general phenornenon at the seed stage.

The taxonomic composition of the native vs. exotic experimental species was relatively balanced, though not completely so. There were, for exarnple, four native grass species and only two alien grass species in the seed bank mortality experiment. The presence of strong taxonomic CHAPTER 3: EXPERIMENTAL SURVEY OF NATNE AND ALEN SEED MORTALITY patterns within the recovery rates and treatment effects, and the correlation of these patterns with further taxonomic pattern in factors such as seed size, suggests that phylogenetic correction methods may be necessary to extricate the causes of any differences between natives and aliens; otherwise, large but irrelevant differences between unrelated taxa rnay obscure rnodest differences between native and exotic species. In the experiment described in Chapter 4, the effects of fungi in the seed bank are investigated further and effects of phylogeny are controlled by the use of phylogenetically independent native-alien contrasts. CHAPTER FOUR

COMPARATIVE EXPERIMENTS ON FUNGAL AND HABITAT EFFECTS ON SEED BANK MORTALITY CHAPTER 4: COMPARATWE EXPERIMENTS

Introduction The literature concerning seed banks is enormous (major reviews in Heydecker 1973, Cook 1980, Roberts 198 1, Thompson 1987, 1992, Leck et al. 1989, Chambers and MacMahon 1994, Fenner 1985, Fenner 1992, Baskin and Baskin 1998). It includes studies in many different disciplines covering a wide range of related subjects and representing efforts in almost al1 types of plant corrmunities and locations. The importance of seed banks in relation to population persistence, to recovery of plant communities following disturbance, to restoration ecology, to management of rare species and communities, and to weed control are among the many topics which have been addressed.

Seed banks also may play an important role in biological invasions. Substantial evidence suggests that the presence of seed banks is important in buffering against the stochastic hazards faced by small populations (Keddy and Reznicek 1982, Venable and Brown 1988, Rees and Long 1992, Rees 1993). Invading species generally face these hazards repeatedly, both at the original site of introduction and with range expansion as small colonizing subpopulations are formed (Barretl and Richardson 1986, Barrett and Husband 1990). It follows that invasiveness may be enhanced in species able to produce persistent seed banks, and there is some evidence that is the case. For example, almost al1 of the world's worst weeds listed in Holm et al. (1977) produce significant seed banks and the presence of persistent seed banks is cited as being one of the most important factors in limi ting the success of biological weed control programs (Holloway 1964, Dahlsten 1986). Crawley, Harvey and Purvis ( 1996) found that British aliens were more likely than natives to have long term seed banks. Finally, Rees and Long (1992) found that 75% of species undergoing range expansion in Britain (both native and alien, but skewed towards üliens) produced long term seed banks.

For a plant to produce a persistent seed bank, its seeds must be able to survive in the soil for extended periods of time. However, little is known of the factors responsible for mortality in the seed bank (Cavers 1983, Cavers and Benoit 1989, Crawley 1992, Chambers and MacMahon 1994, Baskin and Baskin 1998). Bacteria and fungi in the soil are often suggested to be important in causing seed mortality, but very few field experiments have addressed their roles specifically (Baskin and Baskin 1998). Crist and Friese (1993) found that proportions of decomposed seeds arnong 5 shb-steppe species ranged from 4%to 93.5% over 10 months. They implicated fun@ as a causal agent by isolating 7 fungal species from the retrieved seeds. Lonsdaie (1993) is the lone study to have demonstrated increased seed survival after experimentally reducing soil fungi in the field, finding that fungicide addition resulted in a 10- 16% increase in seed survival over 7 months for the exotic Mimosa pigrn in northem Australia. Finaiiy, the demonstrated CHAPTER 4: CWARATIVE EXPERIMENTS effectiveness and extensive use of fungicidal seed coatings in agriculture (Taylor and Hman 1990). points to the potentially importance of fungal seed rnortality in other community types.

If fungi are an important source of seed rnortality in soil, and if seed banking is especially important for invasive species. then invaders may gain a significant advantage if their seeds rarely suffer fungal attack. There are two distinct mechanisms by which this could occur. Both of these hypotheses argue that a low pest Ioad is important to invasion; the distinction lies in how this low load is achieved. First. invaders rnay lose their pathogens when they are transported to a new area (the predator escape hypothesis: Elton 1958, Crawley 1986). Second, perhaps species resistant to diseüse make better invaders because they are less likely to be eliminated by natural enemies in their new habitat (the predator filter hypothesis). These two hypotheses are difficult to distinguish, but the escape hypothesis predicts that invaders should have lower pest loads in new habitats, while the filter hypothesis predicts that pest loads are equally low in both original and new areas. As well. the escape hypothesis relies on the loss of species-specific enemies, while the filter hypothesis is more likely to apply to generalist enemies.

These hypotheses are not exclusive, and both rnay apply sirnultaneously. There is some evidence to support at lrast the predator escape model. Many important soil pathogens appear to be generalists (von Broembsen 1989), but there is also evidence of soil pathogens with some degree of host-specificity (Kirkpatrick and Bazzaz 1982. Van der Putten et al. 1993, Mills and Bever 1998). including some seed pathogens of agricultural plants (Neergaard 1977, Agarwal and Sinclair 1997). A few studies have demonstrated that invaders develop larger seed banks in new regions than in their native habitats, suggesting that escape from seed predators could be occurring. Lonsdale and Segura ( 1987) found that seed banks of Mimosa pigru were approximately 100 times larger in Australia than in its native range in Mexico. Research in coastal shrublands in Mediterranean climate zones of Australia and South Africa (Weiss and Milton 1984) has shown that seed banks of the reciprocally invasive Acacia longifolia (native to Australia) and Chrysanthemoides ~nonilifern(native to South Africa) were increased 44 to 13 16 times in new regions. For Acacia longifolin this was attributed primarily to lower seed production in its native range because of the presence of a seed eating weevil. For Chrysanthemoides rnonilifera seed production only differed between the two regions by a factor of two, but survival in the soil was greatly reduced in its native South Africa.

It is unclear if these cases are exceptional, or reflect general niles. Another study comparing 39 locally-occumng native and alien species (Chapter 3) found significant fungal rnortality, but no consistent differences between natives and aliens. This dernonstrates that natives and diens need CHAP'ïER 4: COMPARATNE EXPERIMENTS not behave in fundamentally different fashions, but the interpretation of these results is made difficult by the fact that native and alien species within the floras of particular areas invariably have different taxonomie distributions (Heywood 1989, Crawley, Harvey and Purvis 1996). This can lead to problems of interpretation, for two reasons. First, relatively subtle native-alien differences may be lost in the "noise" created by the inclusion of very different species in the same dataset. Second, if a significant result is obtained, there is the danger that it may be an artefact produced by phylogenetic confounding, as in the following example.

Suppose we were trying to determine the importance of disease resistance for alien species and we find that the average alien species has significantly greater resistance than the average native. This result suggests that disease-resistant species are more frequent invaders. This is an important conclusion, but this TIP approach (i.e., no phylogenetic correction) cannot eliminate the possibility that differences in disease resistance between natives and aliens are merely characteristics of the phylogenetic groups to which they predominantly belong, and are unrelated to the characters w hich actually lead to invasiveness. The effects of origin are confounded w ith al1 other traits which are conservative with respect to phylogeny (Felsenstein 1985; Harvey and Pagel 1991; Gittleman and Luh 1992; Miles and Dunham 1993). The solution to these problems is to adopt a PIC (phylogenetically independent contrast) approach (Felsenstein 1985; Harvey and Pagel 199 1; Gittlemm and Luh 1992; Miles and Dunham 1993). PICS control for phylogenetic correlation by contrasting native and alien clades which are more closely related to each other than to any other clades in the species set. They describe what aliens do, relative to othenvise similar relatives. In doing this, they reduce both irrelevent phylogenetic noise and the risk that any effects detected are actually spurious correlations. If the PIC approach were used and it was still found that aliens had greater disease resistance than natives, the result would be unlikely to be a consequence of some confounding trait shared by related invaders but unrelated to invasiveness. Some studies already have applied the PIC approach to cornparisons of native and alien floras (Crawley, Harvey and Purvis 1996, Kotanen, BergeIson and Hazlett 1998).

In this chapter, 1 address the questions: 1) Does fungal mortality influence seed persistence in the soi1 seed bank? 2) Does fungal mortality Vary between wetland and upland meadows? and 3) Does fungal rnortality vary between closely related natives and diens? This work adds to that descnbed in Chapter 3 by using congeneric pairs of native and alien species to control for phylogeny, by adding moisture level as a factor, and by increasing spatial replication. By using a PIC approach, 1 am able to reduce the problem of phylogenetic confounding, and to look for subtle effects despite using a wide range of species. As well, this approach suggests the mechanism involved if exotics have low pest loads: since CO-occumngcongenerics are likely to CHAPTER 4: COMPARATiVE [email protected] share their generalist enemies. a difference between natives and exotics is more likely to reflect specialist enemies, and therefore argues for the escape hypothesis. Along with the work outlined in Chapter 3, this is the first study to expenmentally compare seed bank monality over a wide range of CO-occurringnative and alien species. It is also one of a very small number of papers to experirnentally examine the roles of soil fungi and soil moisture on seed bank persistence.

Methods Shtdy site The experiment wm conducted in 10 upland and 10 open wetland plots widely spread around the 347.6 ha University of Toronto Joker's Hill field station, Regional Municipality of York. Ontario (44"02*N, 79"3 1 ' W). Plots were matched for moisture level, openness and vegetation type and were separated by at least lOOm but were arbitrarily chosen within those bounds. The upland plots were in open, dry, sandy old field habitats, with some combination of Bromus inemis, Pon prntensis and Pua compressa dominant. The wetland plots were in open, permanently wet meadows, dominated by species such as Eupatorium rnaculatum and E. pe@bliatum, Agrostis stolonifera, Impatiens capensis, Onoclea sensibilis, Glyceriu stria fa, Equisetzlm arvense and E. fluviatile.

Experimentul Species Thiny herbaceous species which occur pnmarily or entirely in open, upland areas were selected from a pre-existing seed collection. These species were made up of 15 congeneric pairs of one native and one alien species (Table 4.1). WiId populations of üli the experimental species occur in the Regional Municipality of York (Riley 1989), and most of the species occur naiurally within the Joker's Hill property (Chapter 2). Seeds were collected from wild populations in southem Ontario in 1997, with the exception of Ely>nustrachycaulus. This species was purchased from the Pterophylla Fm,Waisingham, Ontario, where seeds were grown in 1996 from plants originating from local, wild seed stock. After collection, seeds were stored dry, in a freezer until use in the experiments. CHAPTER 4: COMPARATWE EXPERIMENTS

Treatments Field soil for the wetland and upland seed bags was collected irnmediately before the experiment. from one wetland and one upland plot respectively. Soi1 was partially dned and sieved but otherwise untreated before use. Seed bags. made from a knee high nylon stocking cut in thirds, were filled with 20 seeds of a single species mixed with 20 ml of field soil and then tied shut. Seed bags were subjected to one of two treatments: 1) control - seed bag saturated in water before burial and 2) fungicide addition - seed bag saturated in fungicide solution before burial. The fungicide solution was a 1 : 100 solution of Maestro 75DF in water (active ingredient Captan - 75% by weight, Zeneca Corp., Stoney Creek, ON, Canada). This concentration was recommended by the manufacturer for use as a dip for bulbs and tubers. Captan is a non- systemic heterocyclic nitrogen fungicide used against a wide range of fungi in the Oomycota, Ascomycota and Basidiomycotina (Sharvelle 196 1. Torgeson 1969. Neergaard 1977) and is noted as being panicularly effective against seed-rotting fungi (Neergaard 1977). It has been shown to have minimal effects on endomyconhizal fungi and both positive and negative effecis on ec tornyconhizae development (Vyas 1WB), depending on plant species.

At each experimental site a 2.5 m by 3.5 m plot was established. Within each plot a 10 x 6 grid was set up with points separated by 0.5 m. At each point. one seed bag was buried 5cm below the soil surface, so that each plot contained al1 30 species subjected to the two treatments. Seed bags were buried in the field in June 1998, early in the natural cycle of seed dispersal, and were recovrred in laie October 1998, at the end of the growing season. After recovery, seed bags were opened and their contents spread over potting mix in lOcm square pots. In a very small number of bags. one or two Bromuî or Efymus seedlings had germinated and forced their way through the bag to the soil surface. These seedlings were added to the total number of seedlings germjnated in the greenhouse. The pots were kept moist in the greenhouse for 3 months. After 1.5 rnonths, seedlings were counted and soi1 was disturbed to allow the more deeply buried seeds a better chance to germinate. A final count of germinating seedlings was done at the end of the 3 month germination penod. CHAPE-R 4: COMPARATIVE EXPERIMFNTS

Table 4.1. Experirnental species for the seed bank - habitat experirnent. Presence on Joker's Hill research station property (JH) is indicated by an "x" (Chapter 2). Native or alien origin follows Morton and Venn (1990) and nomenclature follows Glertson and Cronquist ( 199 1 ).

Congeneric pair Spccies Origin JH ASTERACEAE 1 Lactrica canadensis native Lacruca serriola alien ASTERACEAE 2 Setiecio pauperculus native Senecio vulgaris alien BRASSICACEAE Lepidiunt campestre alien Lepidiunt densiflorum native CAMPANULACEAE Cunipnriula rapiinculoides al ien Canipartula rcltri~tdifolia native CARYOPHYLLACEAE Cerastium arvense native Cerastiunt fontanunt alien CARYOPHYLLACEAE Silene antirrhina native Silerie viilgnris dien CHENOPODIACEAE Cliertopodium albunz alien Chenopodium simplex native CYPERACEAE Carex niuhlenbergii native Carex spicata alien PLANTAGINACEAE Plantago major dien Plarzrago rtigellii native POACEAE 1 Brontus itiemis alien Brornus kalmii native POACEAE 2 Elyrntts repens alicn Elyntus rruchycaulus native POLYGONACEAE Polygonum cilittode native Polygonum corivolvulits alien ROSACEAE 1 Geum aleppicum native Geum urbanum alien ROSACEAE 2 Poren rilla arguta native Porentilla recta alien RUBiACEAE Galiurn boreale native Galiurn verum aiien Total 30 species 15 native 10 native 15 dien 13 alien CHAPTER 4; COMPARATlVE EXPERIMENTS

Analysis Wetland and upland habitats were analyzed separately. Germination percentage values for each species at each plot were arcsin transformed to improve normality (Kirk 1982). A 2-factor randomized block factorial ANOVA was performed on these transformed germination percentage values, blocking by plot, to test for overall fungicide effect.

Origin (nativeMien) effects were investigated in two ways. First, a 3-factor randornized block factorial ANOVA, with origin as a factor and blocking by plot. was performed on the transformed germination percentage data. This is not a PIC analysis since it does not restrict analyses to intrageneric cornparisons; however, it can be used to indicate whether a PIC anülysis is required: the presence of a significant fungicide x origin x genus interaction would indicate that the importance of pathogens to aliens is taxon-dependent. and thus that phylogenetic detrending rnay be required.

Second, origin (native/aIien) effects were investigated with 2-factor randornized block factorhl ANOVAs performed on nativehlien PICS. Two problems with PICS are that most methods require a reliable phylogeny, and that they may result in a substantial reduction in statistical power, especially if done n posteriori (Harvey and Pagel 199 1; Harvey and Purvis 199 1; Lord et al. 1995; Westoby et al. 1995a.b). To avoid these problems. 1 developed PICS a priori (Armstrong and Westoby 1993), and avoided the need for a full phylogeny by simply matching congenenc pairs of one native and one alien species. Each contrast was generated by subtracting alien from native germination values for members of a congenenc pair under the same treatment. at the same plot. For these tests, a significant fungicide effect would indicate that fungi have effects on the relative performance of native and aiien members of the same genus, and hence a phylogenetically-independent fungicide effect.

Of the 600 experimental values (species x treatment x replication combinations) in each of the upland and wetland expenments, 3 and 17 respectively were missing because of seed bags which were not relocated. To restore a balanced design, rnissing values were replaced with the mean of the remaining values in that treatment x species combination (Underwood 1997). The number of degrees of freedom for error in each analysis was reduced by the number of dummied values (Underwood 1997). For ail analyses, a non-interactive mode1 was used, as recornmended by Newman, Bergelson and Grafen (1997). Thus, treatment was treated as a fixed effect, plot was treated as a random blocking effect and the residual was used as the error term. Results Overall seed recovery Overall seed recovery rates were significantly lower in wetland (mean~SEM:20.21 1 .O%) than in upland habitats (mean+SEM: 28.4t1.246). Plot effects were significant in upland, but not wetland areas (Table 4.2). Examination of totals by plot highlights the very consistent nature of the reduction in seed recovery associated with wetland plots. The ranges of mean plot recovery rates obtained in upland and wetland tnals did not overlap. Recovery rates for the 10 wetland plots ranged from 16.9% to 22.6% and the 9 upland rates ranged from 24.8% to 3 1.3%. The reduced recovery rates in the wetland trial were iilso fairly consistent across species, with 22 of 30 species having greater recovery rates in the upland trial (Tables 4.3.4.4).

Overd effects of fungicide addition The results suggest that seeds in wetland plots were subject to higher levels of fungal attack, and that this contributed to the reduced seed recovery rates from wetlands. Fungicide addition significantly improved seed recovery in the wetland trial (Table 4.2) from 18.01 1.3% to 22.41 1.5%, but had no effec t on recovery in the upland trial (28.h 1.7% control vs. X6t1.7% fungicide addition) (Table 4.2). Fungicide addition thus improved recovery in the wetland trial from 63.6% to 78.3% of that in the upland trial. In upland plots, fungicide improved recovery of 15 of the 30 experimental species; in wetlands, 25 of 30 species benefitted. Fungicide effects per plot were significantly larger in wetland plots than in upland plots (unpaired t-test. P=0.03). Recovery was increased with fungicide addition in 9 of the 10 wetland plots and mean fungicide effect per plot was a 25.6% increase in recovery. Fungicide increased recovery in only 4 of 9 upland plots, and al1 increases or decreases were by less thün 7.1%. Mean fungicide effect per upland plot was a 0.6% decrease in recovery. APTER 4: COMPARATIVE EXPERIMEPS

Table 4.2. Results of 2-factor randomized block factorial ANOVAs (fungicide treatment x species) on recovery data for the upland and wetland trials of the seed bank - habitat experiment. Treatment was treated as a fixed effect. plot was treated as a random effect and the residual was used as the error term. *=P

SEED BANK - HABITAT EXPERIMENT -- UPLAND TRIAL Factor d f MS F-value plot 8 0.4 14 3.540*** fungicide treatment 1 0.004 0.034 species 29 8.985 76.823*** fungicide tmt. x species 29 0.167 1.428 error' 369 0.1 17

'degrees of fieedom for error (= 472 - 3) adjusted for 3 dummied values (Underwood 1997); see methods.

SEED BANK - HABITAT EXPERIMENT -- WETLAND TRIAL Factor d f MS F-value plot 9 0.1 88 1.359 fungiçidr treatment 1 3.039 21.968*** species 29 7.038 50.877*** fungicide tmt. x species 29 0.154 1.113 erro? 514 0.138 ldegrees of fieedorn for error (= 53 1 - 17) adjusted for 17 dummied values (Undenvood 1997); see methods. CHAPTER 4: COMPARATIVE EXPERIMENTS

Variation in seed recovery between species Recovery varied significantly with species in both habitats (Table 4.2). In the upland trial, recovery rates for 6 species were less than 5% while recovery rates exceeded 50% for 7 species. Highest recovery rates were obtained for Lepidilcm densiflorum (84.7%) and Senecio vulgaris (81.7%) (Table 3.3). in the wetland trial 10 species had recovery rates below 5% (the same 6 species as in the upland trial plus 4 additional species) (Table 4.4). Only Chenopodium album (59.8%), Lcpidiurn dens~gorum(58.9%) and Serlecio vulgaris (52.8%) had recovery rates above 50%.

Varicrtion in recovery by origiti In 3-factor (non-PIC) ANOVAs, there werz no three-way interactions, implying that relationship did not influence origin x treatment interactions in either habitat (Table 4.5). These origin x treatment interactions were non-significant in both habitats, indicating that native and dien species generally behaved similarly in their responses to fungicide addition. In the upland trial, response to fungicide addition was non-significant, with native recovery drcreasing by 2.4% and alien recovery increasing by 4.2% (Figure 4.1). In the wetland trial, fungicide addition produced a significant increase in recovery. Native recovery increased 22.4% and alien recovery increased by 26.3%.An unexpected result was the evidence that recovery of native seed was less negatively affected by wetland conditions than chat of aliens. Aliens were recovered at a greater rate overall in both the upland and wetland trials but the difference was less pronounced in the wetland trial (Figure 4.1). The difference in recovery between natives and aliens was significant in the upland habitat, but not in the wetland habitat (Table 4.5).

The 2-factor (PIC) ANOVAS, did not significantly alter this interpretation. No effect of fungicide addition on native vs. dien contrast values was detected (Le., natives and aliens responded to fungicide addition similarly; Table 4.6). This result may be expected from the absence of a 3-way interaction, as described above. CHAPTER 4: COMPARATIVE EXPERIMENTS

Table 4.3. Seed bank - habitat expenment. upland trial: Mean + SEM percentrige seed recovery, by treatnient and species (n=9 replicates per species. per treatment, unless othenvise noted). Native species rire indicated by "N. and dien species are indicated by "A".

Species Control Fungiçide MeankSEM Mean~sEM A Broniiis inermis 'Bromus kalmii ACampanula raput~culoides "~antpatiularorurid~olia * Cure-r spicara "Carex naultlenbergii ACera.~tiuntforitarium 'VCeru~ti~marvertse

A Cheriopoiiium album "~herro~odiurnsinaplex

A Elyus repens NEl~niusrrachpcaulus AGaliuna verunl 'VGaliir~~iboreale

*Certrtt it rb~ttrtnr "Geunl uleppicunt *L.uciuca serriola NLuctucucanadensis * Lepidutn carnpestre "Lepidum deruijlontm

A Platirago rriajor "~latitagorugellii A~olygonumconvolvulus "Polyganum cilinode

A Poterttilla recta "Poteniilla arguta *4Setieciovulgaris 'vSeneciopauperculrts "Silette vulgaris NSileriean firrhina CHAPTER 4: COMPARATIVE EXPERTMENTS

Table 4.4. Seed bank - habitat experiment. wetland trial: Mean I SEM percentüge seed recovery, by treritment and species (n=10 replicates per species, per treaunent, unless otherwise noted). Native species rire indicated by "N", and alien species are indicated by "A".

Species Control Fungicide MeaniSEM MeankSEM A Bronrus inemis '"~roniuskalmii

A Campanula rapuncnloides ~v~a~npurrrtlarorundi$olia * Carex spicata NCare.t ntuhlenbergii ACer~tiurnfontanuni "~erastium arverise AChe~iopodiuntalbunt NChenopodiunrsinrplex

A EIynius repens N~lJ~t~~tractiycaulus A~aliumverum "Galium boreale "eunt urbanum %eunt aleppicum "Luçrucu serriolu NLacti4cacattdensis

A Lepidium campesrre N~epidit4mdensiflorim *Plantago major "Plantago rugellii

A Polugonum convolvulus "Poljgonum cilinode "Porentilla recta '"~otertrillaarguta "Senecio vulgaris NSeneciopauperculus "Silene vulgaris %ilene antirrhina CHAPTER 4: COMPARATIVE EXPERTMENTS

Table 4.5. Resutts of 3-factor randomized bIock factorid ANOVA (fungicide treatment x origin x genus) on the recovery data for the upland trial of the seed bank - habitat experiment. Treatment wu treated as ri fixed effect, plot was treated as a random effect and the residual was used as the error term. * = Pc 0.01, ** = P<0.001. *** = P<0.0001

SEED BANK - HABITAT EXPERIMENT -- UPLAND TRIAL Factor df MS F-Value plot fungicide treatrnent oripin genus fungicide treatment x origin fungicide treatrnent x genus origin x genus fung. tmt. x origin x genus errorl

'degrers of freedom for error (= 53 1 - 17) adjusted for 3 dummied values (Underwood 1997); see methods.

SEED BANK - HABITAT EXPERIMENT -- WETLAND TRIAL Fric tor d f MS F-Value plot fungicide treatment origin genus fungicide treatment x origin fungicide treatment x genus origin x genus fung. tmt. x origin x genus erroi

'degrees of freedom for error (= 53 1- 17) adjusted for 17 dumrnied values (Underwood 1997); see methods. CHAPTER 4: COMPARATIVE EXPERIMENTS

Figure 4.1. Results of seed bank - habitat experiment; proportion of seed recovered in upland ÿnd wetland habitats, for native and aiien species, under control and fungicide addition treatments. Error bars are 11 SEM.

Upland

Native Alien

Control Fungicide

Wetland 0.35 , Native

Alien

Control Fungicide CHAPTER 4: COMPARATIVE EXPERIMENTS

Table 4.6. Results of PIC ANOVAs (fungicide treatment x genus) on native vs. alien contrast data for the upland

and wetland trials of the seed bmk - habitat experiment. Treatment was treated as a fixed effect, plot was treated ris a random effect and the residual was used as the error term. * = P < 0.01, ** = P c 0.0I , *** = P c 0.000 1

SEED BANK - HABITAT EXPERIMENT -- UPLAND TRIAL Factor d f MS F-Value plot 8 0.287 1.352 fungicide treatment 1 0.233 I .O48 genus 14 14.338 64.482*** fungicide treatment x genus 14 0.184 0.827 error' 229 50.920 0.222

'degrees of freedom for error (= 232 - 3) iidjusted for 3 dummied values (Underwood 1997); see methods.

SEED BANK - HABITAT EXPEIUMENT -- WETLAND TRIAL Factor d f MS F-Value plot 9 O. 153 0.566 funsicide treatment 1 0.250 0.925 genus 14 1 1.858 43.898*** fungicide treritment x penus 14 0.305 1.129 error? 244 0.270

'degrees of freedom for error (= 26 1-1 7) adjusted for 17 dummied values (Underwood 1997): see methods. CHAPTER 4: COMPARATIVE EXPERMENTS

Discussion Dues furtgal rnorrality influence seed persistence in the soif seed bank? As in the seed bank mortality expenment in Chapter 3, this experiment clearly shows that restriction of soil fungi cm increase seed survival. In this investigation, the fungicide effect was habitat dependent; fungicide significantly increased recovery in wetland meadows while 110 effect was found in upland meadows, at least dunng the relatively short duration of this experirnent. In the wetland habitats, the fungicide effect was somewhat more consistent across species than that in the seed bank mortality experiment in Chapter 3, which was performed in ri dry, upiand site. Given the broad taxonomie range of the experimentai species and the fact that the wetland plots were widely separated, these results demonstrate that in certain habitats fungal mortality of seeds in soil is a significant and general phenornenon.

Soil fungi have often been suggested to cause mortality of seeds in seed banks. There are a number of lines of evidence suggesting the importance of fungi to soil serd banks in natural habitats. Soil fungi (including Eumycota, the true fungi and the "protoctistan fungi" (Kendrick 1992), including Ooniycotü, which are now classified with brown algars in the Stramenopilcs (Sogin and Patterson 1998) are ubiquitous, abundant and include many important decomposers with the ability to secrete extracellular celluiase and proteolytic enzymes (Crist and Friese 1993). Many fungal piant pathogens, including some which can have significant community level effects (Kliejunas and Ko 1976, von Broembsen and Kruger 1984. Augspurger and Kelly 1981) are also soil borne (Garrett 1970). Additionally, the importance of fungicidal seed coatings in agriculture (Taylor and Harman 1990). the fungal scarification of some seeds with hard seed coats (Gogue and Ernino 1979, van Leeuwen 1981, Guttridge et al. 1984) and the presence of fungal-inhibiting compounds in seed coats (refrrences for 8 species given in Baskin and Baskin 1998) al1 suggest that fungi are likely to be an important source of seed mortality in soil. Despite these lines of evidence, my results (including Chapter 3) are among the first which demonstrate the occurrence of fungal mortality in soil seed banks in natural plant communities; Crist and Friese (1993) and Lonsdale (1993) are two rare exceptions.

The particular fungi involved in seed decomposition in soil are very poorly undentood, although those causing seed rots of agricultural plants are comparatively well researched (Neergaard 1977, Agstnval and Sinclair 1997). Important species likely include rnembers of both the primitive Mastigomycota (especially the Division Oornycota) and the Eumycota (Divisions Zygomycota and Dikaryomycota). Due to physiological differences, few fungicides are effective against both groups (Paul et al. 1989). No assays of the fungi in treated and untreated soil were attempted in this study but Captan is widely used in agriculture to convol species of oomycetes, ascomycetes CHAPTER 4: COMPARATIVE EXPERIMENTS

and basidiomycetes in the soil and on fruit, Ieaf and seed surfaces (Sharvelle 196 1, Torgeson 1969, Neergaard 1977). The increases in recovery associated with fungicide addition in this experiment may well underestimate total fungal mortality. as fungitoxic effects of Cüptan are species specific and some pathogens may not have been controlled by the fungicide (Sharvelle 196 1. Torgeson 1969. Neergaard 1977).

Do seed recovery aridfirngal rnortality vnry between wetlnnd and rlpland rneadows? Seed recovery was consistently higher in upland sites, but not al1 of the difference in recovery between habitats can be attributed higher fungal mortality in wetland habitats. Recovery wüs still lower in wetland habitats when fungi were experimentally excluded. The fact that a significant fungicide effect was found in wetland but not upland meadows does strongly suggests that some of this difference was associated with a higher Ievel of fungal mortality in wetlands. With fungicide addition, the difference between upland and wetland recovery wüs reduced by 39.8% relative to the difference between upland and wetland recovery under the control. It is this portion of the upland and wetland difference that is probably attributable to increased fungal mortality in wetlands.

Several factors may account for the lower rates of recovery in wetlands beyond that which cm be attributed to fungi. The most important of these is likely a greater stimulation of germination below ground in wetland habitats associated with the higher soil moisture. A lower rate of recovery for the wetland trial would result fiom this effect because below ground germination was likely fatal for almost all seeds in the experiment due to the bürrier presented by the nylon bags in combination with 5 cm of soil. As described in the Methods, a few grass seedlings with their relativrly large seed reserves and narrowly pointed cotyledons were able to push tlirough the mesh seed bag and survive until recovery, but it is unlikely that smaller seeded species and those with wider cotyledons (most or dl dicots) would have been able to reach the surface. Even among the grasses, most seedlings which germinated in the field did not survive until recovery. Many Elymus and Brumus seeds were observed after recovery to have germinated and died. Reduced wetland recovery could also result if drier conditions induced dormancy in the field, thus preventing fatal germination, and donnancy was then broken in the greenhouse. Laboratory experiments using solutions of low osmotic potentials to simulate water potentials in dry soils have shown effects of this type in some species, including two congeners of experirnental species (Chenopodium bonrts-henricus and Lactuca sariva) (Baskin and Baskin 1998). Conversely, higher moisture level may stimulate some species of seeds into deeper donnancy (Baskin and Baskin 1998). If dormancy was induced in some seeds in the wetland trial and was not broken in the greenhouse germination period, the pattern of reduced recovery in wetlands could also be CHAPTER 4: COMPARATiVE EXPERIMENTS produced. These types of effects limit the extent to which overall recovery rates reflect natural survival rates, but do not significantly affect comparisons between treatments. Finally, wetlands may have a greater concentration of fungal and non-fungal pathogens which were not excluded by the fungicide in the wetland soil, thus reducing wetland recovery. There is evidence that fungal pathogens are genenlly more prevalent in moist soils than in dry soils. The best example cornes from Augspurger (1983) and Augspurger and Kelly (1984), whose extensive studies of spatial variation in the rates of damping off mortality in tropical tree seedlings showed that mortality was greüter in darker areas with higher soi1 moisture and humidity. Rotem (1978) also suggests that this is a general trend which may apply to non-fungal plant pathogens as well.

Very few studies have examined the effects of moisture content of soil on seed bank survival in natural plant communities (Leck 1996). The available evidence suggests that seeds generally survive best in the moisture range in which they typically occur. Moist, high temperature conditions decrease seed survival for many species in controlled storage (Villiers 1972, Ibrahim et al. 1983) but seeds of many aquatic species lose viability when stored dry (Bewley and Black 1982, Bai et al. 1995). Morinaga (1926, cited in Bekker, Oomes and Bakker 1998) found that submergence negatively influenced the survival of seeds of many upland species. In a mesocosm experiment using turfs collected from the field, Bekker, Oomes and Bakker (1998) found that among seeds for which moisture level affected survival. seeds of species typical of wet grasslands tended to survive best in a high water treatment while dry grassland species survived best in a low water treatment. Two of the species found in their study were also used in this experiment. Bekker et al. found that Cerastium fo~ita~tumseeds survived better under the low water treatment. This finding matches my results well, as Cerastiurn fonrariunt showed the greatest reduction in recovery between upland and wetland trials of any species. Bekker et cd. found no effect, however, of water level on Plantago major seed survival, while 1 found significantly reduced recovery of Plantago major in the wetland trial. The relatively small number of Plantago seeds detected in the Bekker et al. study (21 in total) may have precluded detection of significant effects of water level. Overall, my results are in accord with the hypothesis that seeds will survive better in the range of moisture levels they typically encounter. The upland plots included populations of a number of the study species and were typical of the habitats in which most of the experimental species commonly occur. Few of the experimental species were present in the wetland plots and, with the exception of Geum aleppicum, none of the expenmental species tend to occur regularly in Ontario wet meadows of the type used in the study (CSB,pers. obs.). CHAPTER 4: COMPARATlVE Em.NTS

Does fungal mortali~yvary between closely related natives and aliens? Responses to fungicide addition were not significantly different between native and alien species. Native and alien responses to fungicide addition were of a very similar magnitude in both the wetland and upland habitats, and there were no treatment effects on contrast values. Having controlled the effects of phylogeny by using a PIC approach, the fact tbat the congeneric pain of native and alien species behaved similarly in this experiment indicates that alien status perse does not confer resistance to fungi. This result does not eliminate the possibility that alien species as a whole may be more resistant to fungi. If the larger set of alien species tended to corne frorn resistant genera or families, a priori sefection of congeneric pairs would tend to obscure differences between natives and aliens. The failure to detect significant differences between natives and aliens in the TIP analysis of the seed bank mortality experirnent in Chapter 3, however, suggests that this is not the case.

Results agree with those of Chapter 3 in that there was no difference in the response of native and alien species to the reduction of soil fungi. The predator escape hypothesis requires the existence of species specific pathogens for both natives and aliens. Although many fungal plant pathogens are generalists (von Broembsen 1993), host specificity among seed pathogens is known in agriculturai plants (Neergaard 1977, Agarwal and Sinclair 1997), and there is sonie evidence that natural fungal communities associated with different species of seeds Vary within the sarne habitat (Kirkpatrick and Bazzaz 1979, Harman 1983). The most likely explanaiion for the similiir responses of native and alien species to restriction of soil fungi is that the important pathogens of seeds in soil were generalist fungi which do not distinguish between native and alien seeds. It is also plausible that some species specific pathogens of alien seeds have already been inadvertantly introduced to the New World, or that pathogens specific to native species have become adapted to alien congeners since the arriva1 of the aiiens. The Iack of differential response also suggests that the filter hypothesis does not apply. In either case, the results indicate that predator escape by alien seeds is not a general phenomenon at the seed bank stage.

Aliens suffered a slightly greater reduction in recovery between upland and wetland habitats than did natives. The increase in native recovery relative to that of aliens was sufficient to reduce the significant difference between native and alien recovery in the upland trial to non-significance in the wetland triai, although the absolute recovery rate was greater for aliens in both triais. The greater relative performance of natives in the wetland trial was opposite to rny expectation, based on experience with the habitats of the experimental species. Except for Geum aleppicum, none of the experimental species occur with any frequency in Ontario meadows as wet as the wetland habitats in the study (CSB, pers. obs.). The natives in this study are distinctly less abundant in the agricultural part of southem Ontario than are the aliens. The alien species are mostly widespread and very common in old fields and ruderal areas. The native species include two abundant ruderal species (Lepidium dens~florumand Plantago rugellii) and dl do occur in old fields to some extent. Most of the native species used, however, are relatively uncornmon in intensively disturbed areas and they achieve their greatest abundance within southern Ontario in specialized and uncommon communities; dry, sandy prairie remnants and prairie-like old fields, or rock outcrops and limestone pavements (alvan) which were relatively open areas historically due to regular summer drought and frequent fires (Catling, Catling and McKay-Kuja 1992, Catling and Catling 1993, Catling 1995, Catling and Brownell 1995). My prediction, therefore, was that the apparent drought tolennce of natives might corne at the expense of overall niche breadth, resulting in reduced tolerance of wet conditions, while aliens would have a broader range of tolerances. The results reject these hypotheses.

The different results between upland and wetland trials show that habitat is important in determining pathogen effects. The strong differences in recovery between habitats and their very consistent effects across locations and species provide good evidence that seed mortality could be important in restricting the distribution of upland plants in wetlands and in defining wetland boundaries. If the recovery rates from this study translate to increases in recruitment from seed, the observation of changing relative performances of natives and alirns implies that aliens are more likely to have an advantage at the seed stage in upland habitats than in wetland habitats, at least among species of upland habitats. CHAPTER FIVE

GENERAL CONCLUSIONS

CHAPTER 5 - GENERAL CONCLUSION S

b) to determine whether seeds suffer significant losses to predators before incorporation into the seed bank (Chapter 3) Seeds of both natives and exotics suffered highly significant losses to above-ground predators. Vertebrates (birds and rodents) were generally more important thm invertebrates as seed predators, as is generally the case in temperate old fields. Overall predation rates were lower than most other studies, but rnay have been underestimated because of diffïculties in recovering surviving seeds.

c) to determine whether seeds suffer significant tosses to seed predators and pathogens in the seed bank (Chapter 3) Pathogens generally were significant sources of mortality below ground, but invertebrate predators were not. Fungal mortality affected both natives and exotics over a very wide taxonornic range, indicating that fungal rnonality in the soi1 seed bank is of very general signifîcance. The presence of significant fungicide effects over the relative l y short experimental periods suggests that fungi may be very important when compounded over the long periods that many species remain in the seed bank. These are the first field studies to demonstrate a fungal effect on the seed bank survival of a wide range of species.

d) to discover whether seed losses to natural enemies differ among species (Chapter 3) Different species showed different susceptibility to natural enemies. Above-ground. losses to seed predators strongly differed among species. Losses were linked to seed size, with larger seeds tending to suffer greater predation. Below-ground, losses to fungi also varied significantly among species, with rates of loss showing some variation by taxa but no consistent variation by seed size.

e) to determine whether seed losses to natural enemies differ between habitats (Chapter 4) Only the effects of fungi were investigated, but the result was striking: fungal mortality was consistently higher in the wet sites than in upland areas. These results show that habitat is important in detennining pathogen effects. and provide good evidence that seed rnortality may be important in restricting the distribution of upland plants in wetlands and in defining the boundaries of wetland plant communities. f) to determine whether seeds of native and alien species differ in their susceptibility to natural enemies (Chapter 3,4) Aliens and natives did not consistently differ in their response to predators and pathogens. The likely explanation is that both above-ground predators and below-ground pathogens were sufficiently generalist that differences between native and alien seeds (if any) did not alter predation and disease risks. These results argue against both the predator escape and predator filter hypotheses, and suggest natural enemies of seeds do not as a general rule determine invasive ability. g) to determine whether differences in seed losses between natives and aliens occur independent of their phylogenetic relationship (Chapter 4) Phylogenetically Independent Contrasts failed to reveai significant differences between natives and exotics with respect to fungal mortality. These results provide further evidence that alien status is not associated with fungal resistance. and particularly provide evidence against the predator escape h ypothesis.

Limitations of the work As with any study, the work outlined in this thesis is subject to certain limitations. The seed bank quantification in Chapter 2 was a minor component of the study. If, however, more detailed seed bank quantification was required in the future, my work could be improved upon by increasing the number of sampling points within a field and the total amount of soil sampled. Ter Heerdt et al. ( 1996) outline a successful and efficient method for concentrating soi1 samplcs for seed bank quantification, without greatly increasing space requirements for germination. Sampling more soi1 from a greater proportion of a field's surface area would help to reduce the variation caused by the very patchy distribution of seeds in the seed bank. An increased frequency of sampling over a longer period would also be useful to improve the understanding of within and between year flux in seed bank composition and abundance. Additionnlly, future work should incorporate an effort to quantify and/or control the effects of seasonal dormmcy cycles, which were large enough to obscure seasonal patterns of seed input and loss in my work. This could be done by using consistent, controlled environments for germination coupIed with separating seeds from the soil for viability testing.

A few limitations were comrnon to al1 of the experiments outlined in Chapters 3 and 4. The longest period experimental seeds remained in the field was 16 months, whereas seeds are capable of lasting much longer in natural conditions. The link between seed mortality and rnoisture level demonstrated in Chapter 4 also points to a strong potential mechmism for 105 CHA PTm 5 - GENERAI. CONCLU- between-year variation in seed mortality. This could only be quantified with longer term studies. In al1 experiments, seed mortality was inferred indirectly, when seeds failed to germinate. As shown with the seed bank quantification, germination is strongly influenced by seasonal dormancy cycles in many species. Use of consistent and controlled germination conditions and making a greater effort to directly track the viability of individual seeds would help control dormancy effects. No effort was made to identify the specific organisms causing seed mortality. Fungal mortality was inferred by the presence of increased seed recovery associated with fungicide addition. Isolation of fungi, from soi1 and from seeds, using as diverse a variety of media as possible, would rectify this shortcoming. Understanding the fungal species involved in seed mortality would also help to clarify which seeds have species-specific pathogens, an important issue reiared to the predator filter and predator escape hypotheses of rilien advantage. Finally, my work suggests that finding consistent differences between native and alien species is likely to be difficult when looking across a moderately broad taxonomic range. General differences, if present, may tend to be subtle enough to be masked by the large variation present between taxa irrespective of origin. Future studies may have more success in finding native and alien differences by focussing on a narrower taxonomic range (Le. one or a few genera within a family) or by devising a study which can include a very large proportion of the species within a particular reg ion.

General Conclusions Together, the results indicate seed mortality is important. both imrnediately after dispersal and in the seed bank. Species differ, but aliens on average do not differ from natives (with or without effects of phylogeny controlled). Thus the results demonstrate that the predator escape and predator filter hypotheses are not general rules among invaders. This does not meün that these rules never apply; indeed, the limited evidence available suggests some invaders may benefit from reduced populations of seed predators and pathogens. However, such studies have generally focussed on abundant problem species. It may be that, while most invaders do not enjoy reduced seed losses, those that do are more likely to becorne senous problems. By demonstrating that most invaders do not benefit from reduced populations of natural enemies, this research may suggest one important distinction between the rnajority of invaders which do not represent serious environmental threats, and the minority which do. LITERATURE CITED

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C. Sean Blaney. July 1999.

The following list is compiled primarily from the observations and collections of the author made between 1997 and 1999, with a few records from other sources. Approximately 190 species (indicated by 9) are documented by specimens which will be deposited at the Royal Ontario Museum - University of Toronto herbarium (TRT). The remainder of listed species are included on the basis of the authoris sight records, with three exceptions. Steve Varga. OMNR Aurora, provided field notes from 3 1983 visit to the site, which added Corallarhiza trifidu and Vaccinium angustijhliuni to the list. Ongoing research by Richard Joos, University of Toronto Department of Botany, added D~opterisgoldiana, and my lab colleague, Marc Johnson was responsible for several new records in 1999.1 have been quite careful to include only species which have been identified with cenainty. and have collected voucher specimens for any difficult identifications. Very little investigation of the flora of the site Iiad been carriecl out pnor ta its donation to the University of Toronto. The eastern half of the property is almost entirely included by the Ontario Ministry of Natural Resources within the Glenville Hills Kames Earth Science Area of Natural and Scientitic Interest. The Natural Heritage Information Centre at the OMNR office in Peterborough supplied two sources of botanical information on this ANSI. These were a list of 5 locally rare plant species in an environnitntally significant areas study prepared for the South Lake Simcoe Conservation Authority (Ecologistics. 1982) and a partial list of plants found at the adjacent Thornton Bales Conservation Area (South Lake Simcoe Conservation Authority, undated report). These reports included problernatic records and did not note whether species werr recorded on the Joker's Hill property. Due to these difficulties the list below was started from scratch.

The list includes al1 species known to be growing outside of cultivation within the Joker's Hill property. Also listed are native species found in land adjacent to the Joker's Hill property, but not yet found on the site (sçientitic name preceded by "*" - 12 species). A total of 603 taxa (specics and hybrids) are listed. 337 taxa are considered native tu Joker's Hill (those listed in bold typeface) and 166 are considered non-native (listed in repular typeface). Determining native versus non-native status required a few rather arbitrriry judgements.

Several people assisted in the preparation of this list. Peter Ball of the University of Toronto at Mississauga assisted with a number of difticult identifications, especially in the Cyperaceae. Tim Dickinson and Jenny Bull of the Royal Ontario Museum identified the native Crataegus specimens. Peter Kotanen of the University of Toronto at Mississauga offered uscful comments, corrections and encouragement and formatted the document for the world wide web - htt~://www.crin.utsronto.cd-w3~koW~Iants.~.Jarmo Jalava of the Ontario Natural Heritage Information Center compiled the pre-existing information on the site. Steve Varga, Ontario Ministry of Natural Resources and Richard Joos, University of Toronto provided records for species not previously recorded.

Taxonomy, with only ri few exceptions, follows Morton and Venn ( 1990). Wherc widely used synonyms or other potentially confusing alternate binomials exist, these are listed below the species' scientific name. As there are no standard English names for plant species, common names have been taken from a vririety of sources. Afthougli 1 have visited al1 parts of the property looking for plants, mnny additional species will still be found with further tield work. Information on any additional species (preferably documented with specimens) or other comments on the list woufd be welcomed by the author or P.M. Kotanen. EQUISETA CEAE (Horsetail Family )

Equisetum atvense L. Field Horsetail Equisetumflu viatile L. Water Horsetail Equisetum hyemale L. Rough Horsetail §Equisetum pratense Ehrh. Meadow Horsetail Equisetum scirpoides Michx. Dwarf Scouring-rush 5 Equisetum syl vaticurn L. Woodland Horsetail Equisetum variegatum Schleich. Variegated Horsetail

LYCOPODIACEAE (Club-moss Family)

Lympodium clavatum L. Staghorn Clubmoss Lycopodium digirutum A. Braun Running Ground-cedar (LJkrbelliforme) Lycopodium lucidulum Mic hx. Shining Clubmoss fi Lycopodium obscurum L. (sst.) Tree Clubmoss 5 Lycopodium rristachyum Pursh Ground-cedar

O PHIOGLOSSACEAE (Grape-fern Fam ily )

$Bofrychium dissccturn Spreng. Dissected G rapc-îern (B. obliquum) Botrychium multifiduum (Gmel.) Rupr. Lea t he ry G ra pe-fe rn Botrycliium virginianurn (L.) Sw. Rattlesnoke Fern

OSMUNDACEAE (Flowering-fern Fami ly)

Osmunda cinnamomea L. Cinnûmon Fern Osmunda clay~onianoL. Interrupted Fem Osmunda regalis L. Royal Fern

PTERIDACEAE (Spleenwort Fsmily)

Adhnfum pedatum L. Maidenhair Fern

POL YPODiACl3 E (Polypody Family )

Rock Polypody

DENNSTAEDTIA CEAE (Bracken-fern Family )

§Dennstaedtiapunctifobula (Michx.) T. Moore Hay-scented Fern Pteridium aquifinum (L.) Kuhn Bracken Fern

THELYPTERIDACEAE (Marsh-fern Famil y)

§Phegopteris connectilis (Michx.) Watt Nort hem Beech-fern fjThelypieris noveboracensis (L.) Nieuwl. New York Fern Thelypterispaluscris (Salisb.) Schott. Marsh Fern

ASPLENIACEAE (Spleenwort Fatnily) SAsplenium p&yneuron (L.) BSP. Ebony Spleenwort I - VASCULAR PLANTS OF JOW.R'S

DRYOPTERIDACEAE (Wood-fem Family)

Athyriumfilk-femina (L.) Roth. Lady Fern SAthyrium thelypteroides (Michx.) Desv. Silvery Glade-fern Cystopteris bulbifera (L.) Bernh. Bulblet Fern Cystopteris tenuis ( Michx.) Desv. McKay's Fragile Fern §Dryopterisx boottii (Tuckeman) Underw. Boott's Wood-lem (D. intermedia x D. cristata) Dryopteris carthusiana (Vill.) H.P. Fuchs Spinulose Wood-fern (D. spinulosa var. spinulosa) Dryopteris cristaro (L.) A. Gray Crcsted Fern Dryopteris goldiana (Hook) A. Gray Goldie's Fern Dryopteris intermedia (Muhl.) A. Gray Intermediate Wood-fern (D. spinulosa var. intennedia) Dryopteris marginalis (L.) A. Gray Marginal Shield-fern 3Dryopteh x triploidea Wherry Triploid Wood-fern (D. intennedia x D. carthusiana) Gymnocarpium dry opteris (L.) Newm. Oak Fern Matteuccia struthiopteris (L.) Todûro Ostrich Fern Onoclea sensibilis L. Sensitive Fern Polystichum acrostichoides (Michx.) Schott Christmas Fcrn

TAXACEAE (Yew Family)

Tarus canadensis Ma rsh. Canada Yew

Lurir laricina (Du Roi) K. Koch Tama rack Picea glauca (Moench) Voss White Spruce Pinus strobtrs L. White Pine Pirtus s~lvestrisL. Scots Pine Tsuga canadensis ( L.) Carr. Eastern Hemlock

CUPRESSACEAE (Cypress Family )

§Juniperus communis L. Cornmon Juniper §Junipenrs virginiana L. Eastern Red Cedar Thuja occidentalis L. Eastern White Cedar

TYPHACEAE (Cat-tail Family )

Typha angustifolia L. Typha latqolùa L.

SPARGANIACEAE (Bur-reed Family)

SSparganium chlorocarpum Ryd b. Green Bur-reed

POTAMOGETONACEAE (Pondweed Family) g Potamogeton pectinatus L. Sago Pondweed

NAJADACEAE (Naiad Family) III Najasflexifis (Willd.) Rostkov & W. Schmidt Flexible Naiad

AUSMATACEAE (Water-plantain Family)

Alisma plontago-aquatica L. Watcr-plantain (A. triviale) gsagittaria ht$olia W illd. Common Arrowhead

POACEAE (Grass Family)

5Agrosti.s gigantea Roth. Redtop Agrostis scabra Willd. Tickle Grass (A. hyemaiis) Agroslis stolonifera L. Creeping Bent Grass §Alopecurusaequalis Sobol. Short-awn Foxtail §Avenu saîiva L. Oats *Brachyehtrum erectum (Schreber) Beauv. Bearded Shorthusk #Bromusciliatus L. Fringed Brome Bronlus inennis Leyss. Awnless Brome Calamagrosris canadensis (Michx.) Beauv. Canada Blucjoint #Cinna lrztifofia (Trev.) Griscb. Drooping Woodreed Dactylis glonrerata L. Orchard Grass Danthonia spicda (L.) Beauv. Poverty Grriss Digitaria ischaemunr (Schreb.) Schreb. Smooth Crab-gras 5 Digitaria sanguirralis (L.)Scop. Large Crab-grass 4 Echinochloa crusgalli (L.)Beauv. Barnyûrd Grass #Ecliinochloa wiegandii (Fasset) McNeil & Dore Western Barnyard Grass El~nitisrepens (L.) Gould Quac k Grass (Agropy-onrepens) §Elymus vüginkus L. Virginia Wild-rye Festuca arundinacea Schr. Fall Fescue (F. elatior. in part) Festuca rubra L. Red Fescue 9 Festuca subverticillata (Pers.) A. Alex. Nodding Fescue (F.obtusa) Fesruca brevipila Trricey Sheep Fescue ( F. trachyphylla, F. ovina) Glyceriu grandis S. Wats. Tall Manna-gras Glycerio striata (Lam.) Hitchc. Fowl Mannci-grass Leersia orytoides (L.)Sw. Rice Cut -gras Laliurn perenne L. Rye Grass gMilium effusum L. Wild Millet Muhlenbergia mexicunu (L.) Trin. Mexican Muhly-gras Oryzopsis asperifulici Michx. Rough-leaved Mountain-rice §Panicumacuminatum Sw. Tufted Panic-gras (P.lanuginosum, Dkhanthelium acuminatum) Panicum capiiiare L. Common Witch Grass §Panicumdepauperatum Muhl. Depauperate Panic-gras Q Panicum linearifolium Scrib. Linear-leaved Panic-grriss Phalaris arundinacea L. Reed Canary Grass Phleunt pratense L. Timothy Phragmites austraiîs (Cav.) Trin. Common Reed-gras (P. cornmunis) IX 1 - VASCULAR Pl .ANTS OF JOKER'S

Pua annua L. Annual Bluegrass Poa compressa L. Canada Bluegrass Poa palustris L. Swamp Bluegrass Poa prarensis L. Kentucky Bluegms §Pou ahodes L. Woodland Bluegrass Schizaclinepurpurascens (Torr.) Swallen. False Melic Grass §Setariapumila (Poiret) Schultes White Foxtail (S. glauca) §Setaria viridis (L.)Beauv. Green Foxtail §Sphenophalis intemedia (Rydb.) Rydb. Slender Wedge Grass Sporobolus cryptandrus (Torr.) A. Gray Sand Dropseeâ Sporobolus neglectus Nash Overlooked Dropseed Sporobolus vaginiflorus (Torr.)Torr. Ensheat hed Dropseed

CYPERACEAE (Sedze Family)

$Carex albursina E. Sheldon Broad-leaved Sedge $Carex aqiralilis Wahl. Aquatic Sedge Cares arctahz Roo t t Compressed Sedge Carex aurea Nutî. Golden-fruitcd Sedge *§Carexbackii Boott Back's Scdge §Carex bebbii (Baiiey) Fern. Bebb's Sedge §Carex blanda Dewey White Sedge Carex cephaloplrora Mu hl. One-headed Sedge §Carex cornmunis Bailey Common Sedge §Carex cris&tella Britt. Crested Sedge Carex deweyana Schwein. Dewey's Sedge 5 Carex dispenna Dewey Two-secded Sedge ljcarexflpva L. Yellow Sedge Carex gracillimu Schwein. Filiform Sedge Carex granularis Mu hl. Granular Scdge *§Carexlrirtifolio Mack. Hûiry-leaved Sedge $Carex hitchcockiana Dewey Hitchcock's Sedge $Carex hystericina Mu hl Porcupine Sedge $Carex interior Bailey Interior Sedgc *$Carex intumescens Rudge Bladder Sedge §Carex laevivaginata (Kuk.) Mûck. Smooth-sheathed Sedge $Carex hiocarpa E hrh. Slender Sedge §Carex laxiflora Lam. Lme-flowered Sedge Carex ieptalea Wahl. Bristle-stal ked Sdge §Carex leptonervia (Fern.) Fern. Finel y -nerved Sedge §Carex lupulina Mu hl. Hop Sedge §Carex muhlenbergii Schk. Muhlenbcrg's Sedge §Carexpeckii Howe Peck's Sedge Carex peduncuhta Muhl. Peduncled Sedge Carex pensylvanica Lam. Pennsylvania Sedge Carex phntaginea Lam. Plan tain-leaved Sedge Carex platyphylia J. Carey Broad-leaved Sedge 5 Carex pseudo-cyperus L. False-cyperus Sedge §Carex radicrla (Wahl.) Small Radiate Sedge Carex retrom Schwein. Backward Sedge §Carex rosea Schk. Rose Sedge (C. con valuta) SCarex rugosperma Mack Carex scabdu Schwein. Rough Sedge Carer sparganioides W illd. Bur-reed Sedge §Carex spicata Hudson Spiked Sedge * §Carex sprengellii Dewey Sprengel's Sedge Carex stipata Muhl. Crowded Sedge Carex vul;pinoidea Michx. Foxtail Sedge Cyperus bipartilus Torrey River Cypenis (C. rivuloris) §Cyperirs lupulinus (Sprengel) Mrircks (C. filiculmis) Efeocharis erythropoda Steud. Red-foot Spikerush $Eieocharisobtusa (Willd.) Schultes Blunt Spikerush Scirpus tatrovirens Willd. Blackish Bulrush Scirpus cyperinus (L.) Kunth Wool-gras Scirpus microcarpus Presl. Red-sheathed Bulrush (S. rubrotinctus) Scirpus vafidus L. (SA) Soft-stem Bulrush

ARACEAE (Arum Family)

Arisaema triphylium (L.)Schott

LEMNACEA E (Duckweed Family)

Lemnu minor L. Lesser Duckweed Spirodela polyrhb (L.) Schteid. Greater Duckweed Worffm columbirrna Karst. Water-meol

JUNCACEAE (Rush Family)

§Juncus articulatus L. Jointed Rush 9Juncus brevicaudatus (Engelm.) Fern. Short-tailed Rush OJuncus contpressus Jacq. Campressed Rush Juncus bufonius L. Toad Rush 5Juncus dudleyi W ieg. Dudley's Rush luncus effusus L. Soft-stem Rush $Juncus nodosus L. Knotted Rush Juncus tenuis Willd. Slender Rush Juncus torreyi Cov. Torrey 's Rush

LIWACEAE (Lily Family)

Aflium îricoccum Ait. Wüd Leek Asparagus oficinalis L. Asparagus Clintonia borealis (Ait.) Raf. Bluebead Lily Erythronium americanurn Ker Gawler Yellow Trout-lily Hemerocallisjiulva L. Day Lily Maianthemum canadense Desf. Canada Maflower Maianthemum racernosa (L.) Link FaIse Solomon's-seal (Srnilacina racernosa) §Maianthemunt stelhaîum (L.)Link (Srnilacina steüàta) Medeoh virgincOna L. Indian Cucumber-root Polygonatum pubescens (Willd.) Pursh Hairy Solomon's-seal APPENDIX 1 - VASCI JLAR PLANTS OF JOW'S HILL

Smilar herbacea L. Carrion Flower gSmilar hispkfu Torr. Bristly Greenbrier Streptopus roseus Michx. Rose Twisted-stalk Trillium erecturn L. Red Trillium Trillium grandiF,rurn (Michx.) Salisb. White Trillium Uvularia grandiira Sm. brge-flowered Bellwort

IRIDA CEAE (Iris Family )

Iris versicolor L. Blue Fias Sisyrinchium montanurn Greene Blue-eyeà Grass

ORCHIDACEAE (Orchid Famil y)

*Corallorhb cf. maculaia (Raf.) Ra f. Spotted Coralroot Corallorhira trifida Chat. Early Comlroot Cypripedium cakeolus L. Yellow Lady's-slipper Cypripedium reginae Walter Showy Lady 's-slippcr Epipactis helleborine (L.) Crûntz Helleborine $Caleuris spectabiiîs (L.) Raf. Showy Orchis fiparis loeselii (L.) Richard Loesel's Twayblade * §Malaris monopyllos (L.) Swallen White Adder's-mouth Pldanthera hyperborea (L.) Lindley Northen Green Orchid Spiranthes cernua (L.) Rich Nodding Ladies'-tresses

SALICACEAE (Willow Family )

Populus bahmgera L. Balsam Poplar Populus grandidenta fa Mic hx. Large-toothed Aspen P opulus tremuloides Michx. Trembling Aspen Salix amygdaloides Anderss. Peach-leaved Willow Salir bebbiana Ssrg. Beaked Willow Salir discolor Muhl. Pussy Willow §Salk exigua Nutt. Sandbar WiHow $Salk eriocepliala Michx. Stiff WiHow $SalLr cf: x mbens Schrrin k Hybrid Willow (S.fragilis x S. alba) Salk lucida Muhl. Shining Willow Salir petiolrrris Smith Slender Willow $Salk serissima (L. Bailey) Fern. Autumn Willow

JUGLANDACEAE (Walnut Frtmily)

Caqa cordfownis (Wangenh.) K. Koch Bittemut Hickory Juglans cinerea L. Butternut

BETULACME (Birch Family)

Betula allegheniensis B ritton Yellow Birch Betula papynyera Marsh. White Birch Carpinus caroliniana \Val t Blue Beech Corylus cornuta Marsh. Beaked Hazel Oshya virginirina (Miller) K. Koch Hop Hornbeam FAGACEAE (Beech Farnily)

Fagus grandifolka Ehrh. American Bcech Querciis aiba L. White Oak Quercus macrocatpa Michx. Bur Oak Quercus rubm L. Red Oak

ULMACEAE (EhFamily)

American Elm

URTICACEAE (Nettlc Family)

Boehme& cylindrica (L.)Sw. False Nettle Loporîea canadensis (L.)Wedd. Wood Nettle 5Parietarkz pensyl vanica Mu hl. Pellitory §Piles fontana (Lunell) Rydb. Dark-seeded Cleanveed Pilea pumila (L.) A. Gray Cleanveed U&a dwica L. ssp. gracilis Ait. Tall Nettle

POLYGONACEAE (Buckwheat Family)

Polygonunr achoreum Blake Homeless Knotweed Poljgorium aviculare L. Prostrate Knotwced Polygonum convolvulus L. Black Bindweed §Poljgonunt hydropiper L. Water Pepper Polygonum hpathifolium L. Nodding Smartweed Polygonum persicaria L, Lady 's-thumb Rumex acerosella L. Sheep Sorrel Run1e.r crispus L. Curled Dock Runiex obatsifolius L. Bitter Dock Rumex orbicuhus Gray Great Water Dock

CHENOPODIACEAE (Goosefoot Frirnily )

Atriplex patula L. Spearscale Chenopodium album L. Lamb's Quarters §Chenopodium glaucurn L. Oak-leaved Goosefoot 5 Chenopodium rubrurn L. Coast Blite 9 Chenopodium simpkx (Torrey) Raf. Maple-leaved Goosefoot

AMARANTHACEAE (Amaranth Famil y)

Tumbleweed Redroot Pigweed

PORTUUCEAE (Purslane Famil y)

Claytonia caroliniana Michx. Wide-leaved Spring Beauty Portulaco okmcea L. Purslane

CARYOPHYLUCEAE (Pink Family)

Arenaria serpyllifolia L. Thyme-leaved Sandwort Cerustium fonranum Baumg. Mouse-ear Chic kweed (C. vulgatum) Diarithus armeria L. Deptford Pink Sapotlaria oficinalis L. Bauncing Bet Silene antirrhina L. Sleepy Catchfly Silene larifalia Poiret White Campion (S. alba. Lychnis ulba) Silene nocriflora L. Night-fiowering Catchfly Silene vulgatis (Moench) Garc ke Bladder Campion §Srellaria grarninea L. Grass-lcaved Stitchwort $StellaM longiJoli0 Willd Long-leaveà Stitchwort Srellana media (L.) Cyrillo Common Chickweed

RANUNCULACEA E (Crowfoot Family )

Actaea pachypoda (L.)Mill. White Baneberry Actaea rubra (Ait.) Willd. Red Baneberry 9Ac)aea x ludovici Boivin Hybrid Baneberry (A. pachypoda x A. rubra) Anemone cylindrica A. Gray Long-fruited Anemone Anemone virginiuna L. Thimbleweed $AquilegÙz canadonsis L. Wild Columbine gAquilegia vulgaris L. Garden Colurnbine Caùha palustris L. Marsh Marigold Clemaîis vùginiana L. Virgin's Bower Coptis triifdia (L.) Salisb. Goldthread Hepatica acutiloba DC. Sharp-lobed Hepatica Ranunculus abortivus L. Kidney-leaved Buttercup Runuricrilus acris L. Common Buttercup Ranunculus recurvatus Poiret Hooked Buttercup Ranunculus sceleratus L, Cursed Buttercup Thalictrum dioicum L. Early Meadow Rue Thlictrum pubescens Pu rsh Tall Meadow-rue

BERBERIDACEAE (Barberry Family)

Berberis thunbergii DC. Japanese Barbeny Caulophyllum thalictroides (L.) Michx. Blue Cohosh Podophyllum peltatum L. May-apple

PA PA VERACEAE (Poppy Famil y)

Chelidoniuni majus L. Celandine Sangtrinaria canadensir L. Bloodmt

FUMARIA CEAE (Corydal is Family )

Dicenîra canoderrsis (L.)Bernh. Squirrel Corn

CAPPARACEAE (Caper Family)

5 Cleome hmsleriana Chodat Spider Fiower (C. spinosa) BRASSICACEAE (Mustard Family)

Alliaria petiolata (M. Bieb.) Cav. & Gr. (A. oficinalis) Alyssum alysoides (L.)L. Yellow Alyssum Arabis gWm (L.) Bemh. Smooth Rock-mess Barbarea vulgaris R. Br. Yellow Rocket SCamelina microcarpu Andrz. SrnaIl-seeded False-flax Capsella bursa-pastoris (L.) Medi k. Shepherd's Purse Cardamine dîphylla (Michx.) A. Wood Toothwort (Dentriria diphylla) Cardamine pensylvanica Muhl. Pennsylvania Bitter-cress Erysiniurn cheiranthoides L. Worrnseed Mustard Wesperis matrunalis L. Dame's Roc ket Lepidium densiflorum Schrad. Peppergms Naturtium oncinale R. Br. Water-cress 4 Ron@papalustris (L.) B-r ssp hispida (Desv.) Jansell Marsh Yellow-cress Siriapis amensis L. Charlock (Brassica kaber) Sysimbrium oncinale (L.)Scop. Hedge Mustard Thlarpi arvense L. Field Penny-cress

CRASSULACEAE (Orpine F~imily)

Sedum telephiuni L.

SAXIFRAGACEAE (Saxifrage Family)

§Chrysospleniurn americanum Hoo ker Golden Saxifrage Mdella diphylla L. Bishop's-cap Mitrewort Mitella nuda L. Naked hiitrewort Tiarella cordgolia L. Foamflower

§ Ribes alpi~iurnL. Alpine Currant Ribes americonum Mill. Wild Black Currant Ribes cynosbati L. Prickly Gooseberry 9Ribes hùîellum Michx. Hairy Gooseberry *$Ribes lacusîte (Pers.) Poir. Bristly Black Curront Ribes rubrum L. European Red Currant Ribes triste Pallas Swamp Red Currant

HAMAMELIDACEAE (Witch-hazel Famify)

ROSACEAE (Rose FamiIy)

Agrimonia gtyposepala Wallr. Hooked Agrimony §Ame&nchier kvis Weig. Srnooth Servicebemy §Amelanchier interior Nielson Interior Seniceberry Crataegus nwnogyna Jacq. English Hawthom APPENDIX 1 - VASCUI,AR PJ .mTS OF JOKER'S HILL

Crrrtaegus punctcrca Jacq. Dotted Hawthorn Crataegus macracantha Lodd Large-thorned Hawt horn (C. succulenta var. macracantha) Crataegus sect Coccineae hawthorn sp. - section Coccineae Fraga~vesca L. Woodland Strawberry Fragaria vwginiana Dechesne Wild Strawberry Geum akppicum Jacq. Yellow Avens Geum canadense Jacq. White Avens $Geurn laciniclrum Murr. Slashed Avens OGeurn rivale L. Water Avens Malus pumila Miller APP~~ (Pymmalus) Q PotentiUa orguta Pursh Tall Cinquefoil Potentilla norvegica L. Rough Cinquefoil Poteritilla recta L. Sulphur Cinquefoil Prunus nigra Ait. Canada Plun Prunus pensylvanica L.f. Pin Cherry Prunus serotina Ehrh. Black Cherry Prunus virgininna L. Choke Cherry Pyrus conin~unisL. Pear Rusa bhnda Ait. Smmth Wild Rose $Rosa carolina L. Pasture Rose Rosa nrultiflora Thunb. Multiflora Rose Rubus allegheniensis Porter Common Blackberry Rubus idaeus var. strigosus L. Red Raspberry (R. strigosus) Rubus occidentalis L. Black Raspberry Rubus odoratus L. Purpie-fiowering Rospberry Rubus pubescens Raf. Dwarf Raspberry Sorbus aucuparin L. European Mountain-ash $ Waldsteiniafragarioides (Michx.) Tratt. Barren Strawberry

FABACEAE (Bean Family )

Amp hicarpueu bracteatu (L.)Fern. Hog-peanut Desmodium canadense (L.) DC. Showy Tick Trefoil Desmodium glutinosum (Muhl.) Wood Glutinous Tick-trefoil QLathyrustuberosus L. Tuberous Vetchling Lotus corniculatus L. Bird's-foot Trefoil Medicago lupulina L. Blrick Medick Medicago sativa L. ssp. sativa Alfalfa ssp. falcata (L.) Arcangeli Yellow Lucerne Melilotus alba Medikus White Sweet Clover Melilorur oflcinalis (L.) Pallas Yellow Sweet Clover Robinia pseudo-acacia L. Black Locust Trifalium campestre Schr. Pinnate-leaved Hop Clover (T.procumbenr) Trifalium hybridum L. Alsike Clover Tnfolium pratense L. Red Clover Tnyolium repens L. White Clover Vicia cracca L. Cow Vetch Vicia sativa L. Spring Vetch Vicia tetraspermu (L.) Moench Spmw Vetch OXAUDACEAE (Wood Sorrel Family ) gOxalis metosella L. Wood Sorrel Oxalis s&icto L. YePow Sorrel (O. foniana, O. europaea)

GERANIACEAE (Geranium Family )

Geranium robertianum L. Herb Robert

EUPHORBIACEAE (Spurge Frimily)

Acalypha virginica Raf. Three-seeded Mercury (A. rhomboidea) #Chaniaesyce gljprospernra (Engel m. ) Smdl Engraved Spurge (Euphorbia gljptosperma) §Chamaesyce maculola (L.)Small Spotted Spurge (Euphorbia supina, E. macula&) Euphorbia cyparissias L. Cypress Spurge

POLYGALACEAE (Polygala Family)

ANACARDIACEAE (Cashew Frimily)

Rlzus radicans L. Poison Ivy (Toxicodendron radieans) Rhus typhina L Staghorn Sumac

CELASTRACEAE (Bittersweet Ftimily )

Ce(astrus scandens L. Bittersweet QEuonymus aiatus (Thunb.) Siebold Winged Euonymus

ACERACEAE (Maple Family )

SAcer ginnala Maxim. Amur Maple Acer neglrndo L. Manitoba Maple *§Acer nigrum Michx. f. Black Maple Acer plaranoides L. Norway Maple Acer rubrum L, Red Maple Acer sacchan'num L. Silver Maple Acer saccharum Marsh. Sugar Maple Acer spkatum Lam. Mountain Mapte

BALSAMINACEAE (Touch-Me-Not Family)

Impatiens capensis Meerb. Spotted Touch-Me-Not

RHAMNACEA E (Buckhorn Family )

Common Buckthorn XII APPENDIX 1 - VASCULAR PI-ANTS OF JOKFP'S HI1.L

VlTACEAE (Vine Farnily)

Parthenocissus inserta (Kerner) Fritsch Virginia Creeper (P. vbcea) Vitis riparia Michx. Wild G rape

TIWACEAE (Linden Fiunily)

Tilia americana L. Basswood § Tilia cordara Mil 1. Little-leaf Linden

MALVACEAE (Mallow Family)

Common Mallow

CLUSIACEAE (St. Johnswort Family)

Hypericum pe~oratumL. Comrnon St. Johnswort 3 Hypericum punctatum Lam. Dotted St. Johnswort

CISTA CEA E (Rock-rose Family )

$Lecheu intermedia Britt. Intermediate Pinweed

VIOLACEAE (Violet Family)

5 Viola bhn& Willd. Sweet White Violet Viola canadensis L. Canada Violet Q Viola conspersa Reich. Dog Violet Viola cucullata Ait. Marsh Blue Violet §Viola mackfoskeyi F. Lloyd Northern White Violet Viola pubescens Ait. Downy Yellow Violet (incl. V. pensyfvanica, V. eriocarpa) Vioh renifolia Gray Kidney-leaved Violet Viola rostmîa Pursh Long-spurred Violet 5 Viola seikirkii Purs h Selkirk's Violet Viola sororiiz Willd. (s.L) Wooly Blue Violet

TH YMELAEACEAE (Mezereum Famil y)

LYTHRACEAE (Loosestrife Frimily )

Lythrum salicaria L. Purple Loosestrife

ONAGRACEAE (Evening Primrose Family)

Circaea alpim L. SmaH Enchanter's-nightshade Circaea lutetirrna L. Tall Enchanter's-nightshnde (C. quadrisukaîa) Epilobium cilicltum Rd. Northern Willow-herb (inci. E. adenocaulon, E. glandulosum) APPENDIX 1 - VASCULAR PI-ANTS OF-

~Epilobiumhirsutuni L. Hairy Willowherb 5 Epilobium leptophyllum Raf. Narrow-leaved Willowherb Epilobium parviflorum Sc hre ber Small-flowered Willowherb ~Epilobiumstrictum Spreng. Downy Willowherb Oenothera biennis t. (s.L) Evening-primrose $Oenotheraperennis L. Sundrops

ARAWACEAE (Ginseng Family)

Aralia nudicaulk L. Wild Sarsaparilla Aralia racernosa L. Spikenard Panax quinqu$olius L. American Ginseng

A PIACEAE (Parsley Family)

Cryptotaenia canadensis (L.)DC. Honewort Daucus carota L. Queen Anne's Lace Hydrocotyle americana L. Water Pennywort Osrnorhiza chytoni (Michx.) C. B. Clarke Sweet Cicely Sium suave Walter Water Parsnip Sanicuiu marilandica L. Black Snakeroot

CORNACEAE (Dogwood Famify)

Cornus alternifolk L. f. Alternate-leaved Dogwood §Cornus canadensis L. Bunchberry Cornus rugosa Lam. Round-leaved Dogwood Cornus stolonvera M ichx. Red-osier Dogwood

PYROLACEAE (Pyrolri Frimily)

§Chimaphila urnbellata (L.) Bart. Pipsissewa SMoneses uniflora (L.) Gray One-flowered Wintergreen 5Pyrola americana Sweet Round-leaved Pyrolo (Pyroiu rotundifolia var. americana) 8 Pyrola asar~oliaMic hx. Pink Pyrola Pyrola elliptka Nutt. Shinleaf

MONOTROPACEAE (Pinesap Family)

§Monotropa hypopithys L. Pinesap Monotropa unif2ora L. Indian Pipe

ERICACEAE (Heath Family)

Gaulthe~procumbens L. Wintergreen Voccimium angustifolium Ait. Low Biueberry

P RIMULA CEAE (Primrose FamiIy )

Lysimachia ciliala L. Trientalis borealis Raf. OLEACEAE (Olive Family )

Fraxinus urnericana L. White Ash Fraxinus nigra Marsh. BIack Ash 5 Frarinus pensylvanica Marsh. Red Ash Syringa vulgaris L. Lilac

GENTIANACEAE (Gentian Farnily)

Clased Gentian Fringed Gentian

APOCYNACEAE (Dogbane Family)

Apocynum androsaem~uliumL. Spreading Dogbane Apocynum cannabinum L. Indian Hemp

ASCLEPIADACEAE (Milkweed Family)

Asclepios incarnata L. Swamp Milkweed Asclepias sy~caL. Common Milkweed rjCynartchuni rossicurn (Kleopov) Borh. Swallowwort ( Vincetoxicum niedium l

CONVOLVULACEA E (Bindweed Frimily)

Calystegia sepium (L.) R. Br. Rdge Bindweed (Con volvulus sepium) § Calystegia spithamaea (L.) Pursh Low Bindweeà Convolvulw arverisis L. Field Bindweed S Cuscuta gronovii Willd. Dodder

H YDROPHYLLACEAE (Waterleaf Frtmily)

* 9Hydrophyllum canadense L. Crincida Waterleaf Hydrophyllum virginiana (L.) Johnst. Virginia Waterleaf

BORAGINA CEAE (Borage Family )

Cynoglossum oficirtale L. Hound's Tongue Echium vulgare L. Viper's Bugloss DHackelia virginiana (L.) Johnst. Virginia Stickseed myosotis scorpioides L. Watet Forget-me-not 5 Myosotis sylvatico Ho ffm. Woodland Forget-me-not

PItryma kptostachya L. Lopseed Verbena hastkzta L. Blue Vewain Q Verbena stricu Vent. Hoary Vervain Verbena urticifolia L. White Vervain

LAMIA CEAE (Mint Family) Cfinopodium vulgare L. Wild Basil (Satureja vulgaris) Galeopsis tetrahit L. Hemp Nettte Glechoma hederucea L. Ground Ivy 5Hedeoma hispida Pu rsh Hairy Pennyroyal Leorutrus cardiaca L. Cammon Motherwort Lycopus americanus Mu hl. Cut-leaved Bugleweeed Lycopus uniflurus Michx. Northern Bugleweed Mentha arvensis L. Common Mint Menrha x piperita L. Peppermint (M. aquatica x M. spicasal Monarda fitubsa L. Wild Bergamot Nepeta cararia L. Catnip Prunelin vulgaris L. Heal-al1 Scutellaria latetifloru L. Mad-dog Skullcap

SOLANACEAE (Nightshade Farnily)

Physalis heteropiaylla Nees Clammy Ground-cherry §Solarium tuberosum L. Potrito Solarium dulcanuira L. Bittersweet Nightshade §Solarium nigrurn L. (s.1.) Black Nightshade

SCROPHULARIACEAE (Figwort Family)

Chaenorrhinurn mirius (L.)Longe Dwarf Snlipdragon Chelone glabra L. Turtlchead $Gratiola neglecta Torr. Clammy Hedge-hyssop Linaria vulgaris H il1 Common Toadflax Mimulus tingens L. Square-stemmed Monkeyflower 9 Penstemon digitah Nuit. Fox-glove Beard-tongue Verbuscum thupsiw L. Common Mullein Veronica americana (Raf.) Schw. Americnn Brooklime Vernriica arvensis L. Corn Speedwell Veronica officinalis L. Comnion Speedwell Veronica peregrina L. ssp. peregrina Purslane SpeedweII Veronica serpyllifolia L. Thyme-leaved S peedwell

OROBANCHA CEA E (Broom-npe Family )

Epvagus virginiana (L.) Bart.

PLANTAGINACEA E (Plantain Family)

Plantago major L. Common Plantain Plantago lanceoluta L. English Plantain Plantago rugelii Decne. Rugel's Plantain

RUBIACEAE (Madder FamiIy)

Galium aparine L. Cleavers $Galium boreale L. Northern Bedstraw Galium circaezans blichx. White Wild Licorice Galium mollugo L. Wild Madder #Galium lanceoiaîum Torr. Yellow Wild Licoricc 5 Cafium palustre L. Marsh Bedstraw §Gdium tinctorium L. Dyer's Bedstraw *§Galium tn~idumL. Small Bedstraw Galium tnflonrm Michx. Frsgrant Bedstraw Galium verum L. Yellow Bedstraw Mitcheh repens L. Partridgeberry

CAPRIFOLIACEAE (Honeysuckle Family )

Diewilh lonicera Mill. Northern Bush Honeysuckle §Linnaeu borealis L Twiriflower Lonicera canadensis Bartr. Canada Honeysucklc Lonicera dioica L. Glaucous Honeysuckie &Lotiicera x bella Zribel Hybrid Honeysuckle (L.tatarica x L, niorrorvii) .iLonicera hirsuta Eaton Hairy Honeysuckie $Lotliceru tata nca L. Tartariiin Honeyusuckle

Sambucus canadensis L. Common Elder Sambucus racemosa L. Red-berried Elder (S. pubens) Symphoricarpos albus (L.)Blake Snow berry Triosteum aurantiacum Bich. Wild Coffee Viburnum aceri$olium L. Maple-leaved Viburnum 3 Viburrium cassinaides L. Wild Raisin $ Vibumum lanratia L. Wayfaring Tree 5 Viburnum lantancrides Michx. Hobblebush (V. aln~olium) Viburnum lentago L. Nannyberry $ Vibumum opulus L. Guelder Rose *$ Viburnum trilobum Marsh. Highbush Crrinberry (Viburnum opulus var. americatta)

CUCURBITACEAE (Gourd Farnily)

§Cucurbita sp. domestic gourd species Ecirinocystis lobata (Michx.) T.& G. Wild Cucumbcr

CAMPANULACEAE (Bluebell Family )

Campanula aparinoides Pursh Marsh Bellfiower (C. uliginosa) Campanula rapunculoides L. Common Bellflower Lobelia in- L, Indian Tobacco Lobelia siphilitka L. Great Lobelia §Lobelia spicrra Lam. Spiked Lobelia

ASTERACEAE (Composite Fmily)

AchiUea miUefolium L. Common Yarrow Ambrosia artemisiifolia L. Common Ragweed Anaphalis mugarhcea (L.) Benth. & Hook Pearly Everlasting APPENDIX 1 - VASCULAR PLANTS OF JOKER'S

§Antennaria neglecta Greene Field Pussytoes Antennaria parlinii Fem. Plantain-leaved Pussytoes Arctium minus (Hill) Bernh. Common Burdock §Artemisiu ludoviciana Nu tt. Western Sage SArternisia biennis Willd. Biennial Wormwood §Aster x amethystinus Nutt. Amethyst Aster (A. ericoides r A. novae-angliae) Aster cord$oliUs L. Hcart-leaved Aster Aster ericoides L. Many-nowered Aster (Virgulus erkoides) Aster lanceolatus W il Id. Panicled Aster (A. simplcx) Aster Iareriflorus (L.) Britt. Calico Aster Aster macrophyllus L. Large-leaved Aster Aster novae-angliae L. New England Aster (Virgulus novae-angliae) Aster oolentangiensis Riddell Azurc Aster (A. azureus) §Aster pilosus Willd. Heath Aster Aster puniceus L. Purple-stemmed Aster $Aster uropltyllus Lind. Arrow-leaved Aster Biàens cernua L. Bur-rnarigold Biàens frondosa L. Beggar's-ticks Bidens tripartifa L. (s.1.) Stick-tight (B. comosa, B. connata) §Bidens vulgata Greene Tall Beggar's-ticks Carduus acanrhoides L. Plumeless Thistle Cenraicseajacea L. Brown Knapweed Chrysanthentum leitcanrhen~umL. Ox-eye Daisy Cichoriunz intybus L. Comrnon Chicory Cirsiuni arverise (L.) Scop. Canada Thistle Cirsiunt vulgare (Sav i ) Tenore Bull Thistle Cunyza canadensis (L.) Cron. Horseweed Crepis teetoruni L Narrow-leaved Hawk's-beard Erigerm annuus (L.) Pers. Daisy Fleribrine Erigeron phiiadelphicus L. Philadelphia Fleabane 8Erigeron pukhellus Michx. Robinfs Plantain Erigeron sttigosus Muhl. Rough Fleabane Eupatorium maculatum L, Spotted Joe-Pye- Weed Eupcrtorium perfoliatum L. Boneset Eupcrtorium rugosuna Houtt. White Snakeroot Eutlurmia graminifolk (L.) Salisb. Grass-leaved Goldenrod (Solidogo graminifolk) Galinsoga quadriradiata Ruiz & Pwon Quickweed Cnaplrctlium obtus~oIiumL. Sweet Everlasting Hieracium auranriacurn L. Orange Hawkweed Hieracium caespitosurn Dumort. Field Hawkweed (H. pratense) Hieracium pilosella L. Mouse-ear Hawkweed Hieracium piloselloides V ill. King Devi1 (H. flo renrirt um) lnula heleniurn L. Eiecampane Lactuca biennis (Moench) Fern. Tall Blue Lettuce Lactuca canadensis L. Canada Wild Lettuce Lactuca sem'ola L. Prickly Lettuce Matricaria matricadides (Less. ) Porter Pineappleweed Prenanthes alrissima L. Tall White Lettuce Rudbeckia hirio L. Black-eyed Susan (R.serotina) Rudbeckia iriloba L. Brown-eyed Susan SSenecw aureus L. Golden Ragwort EjSenecio i~iscosusL. Sticky Groundsel Senecio vulgaris L. Common Groundsel Solidogo alrissima L. Tall Coldenrod *Solidago arguta Ait. Sharp-leaved Goldenrod Solidago caesia L. Blue-stemmed Goldenrod Solidago canaàensis L. Canada Goldenrod Solidago flexicaulis L. Zig-zag Goldenrod Solidago gigantea Ait. Late Goldenrod Solidago nemomlis Ait. Gray Goldenrod Solidago rugosa Ait. Rough-stemmed Goldenrod QSolÙiago uliginosa Nutî. Bog Goldenrod Sonchus arvensis L. Field Sow Thistle Sortchus asper (L.) Hill Spiny-leaved Sow Thistle Sonchus oleraceus L. Annual Sow-thistle 8 Tanacetum vulgare L. Common Tansy §Tararacum erythrospennum Anderz. ex Besser Red-seeded Dandelion Taruxacum palustre (Lyons) DC. (S.1. ) Mmh Dandelion {T. turfosurn) Taraxacurn opcinale Weber Common Dandelion Tragopogon dubius Scop. Goat's-beard Tragopogon pratertsis L. Yellow Goat's-beard Tussilagofarfara L. Colt's-foot Rare native plants of Joker's Hill and immediate surroundings C. Sean Blaney, 1999. The following native species are considered rare at some level between local and national. A number of the species listed as locally rare in Riley (1989) have probably since been removed frorn the OMNR rare list as their status has become better understood. An updated version cf this list will be prepared after consultation with the OMNR. The list includes only records based on specimens 1 have seen. One additional locally rare species, Juglans nigrn (Black Walnut). was reported for the Glenville Hills Environmentally Signifiant Area (which includes rnuch of the Joker's Hill property) in Ecologistics (1982). If correctly identificd, this record is very likely based on an introduction or adventive record, rather than a native occurrence in the area. Numerous JrlgIutzs rtigrn are planted in the western portion of the farm, and the site is north of the species' recognized native range (Farrar 1995). Codes: * - The record for the species is supported by a specimen (to be deposited at TRTE). N - rare in Canada (National Museum of Natural Sciences 1988). P - rare in Ontario (Oldham 1996) R - rare in the former OMNR Central Region (Riley 1989). Y - rare in Metropolitan Toronto and York Regional Municipality (Riley 1989). ' - not previously recorded in Mrtropolitün Toronto and York Regional Municipality (Riley 1989). ' - recorded outside the boundaries of the Joker's Hill propeny, but nearby ' - collected by Richard Joos. a graduate student icndsr Terry Carleton. Specimen seen by CSB. Lycopodiuni obsc~rrttrtlL. (.ut) Ground-pine Qcopodium rristachyuni Purs h Ground-cedar Equiserrrm pratensr Ehrh. Meadow Horsetai l Botrychium dissectirin Spreng. Dissected Grripe-fem Dennstaedtia punctilobiïln (Michx.) Moore Hay-scented Fern Asplertirrm plarynewon (L.) Oakes Ebony Spleenwort Dryopteris gokiiana ( Hoo k.) Gray Goldie's Fern Polypoditrm virgirziclnunl L. Rock Polypody Jrcniperrts contrnunis L. Common Juniper lrmiperrrs virginicrntr L. Eastern Red Cedar Fesruca subverticillata (Purs.) E. Alexeev Nodding Fescue (F. obtr~saBiehl.) Panicum ùepauperatwn Mu h 1. Depauperate Panic Grass Panicum linearijiolium Bri tt. Narrow-leaved Panic Grass Sporobolris vaginif orus (Torrey) Torre y Ensheathed Dropseed Carex cephalophora Muhl. One-headed Sedge CarexJlava L. Yellow Sedge Carex hitchcockiana Dewey Hitchcock's Sedge Carex lasiocarpa Ehrh. Wooly-fruited Sedge Carex muhlenbergii Schk. Muhien berg's Sedge Carex rugosperma Mack. Rough-seeded Sedge Cyperrrs lupulinus (Spreng.) Marcks CYpems. Juncus brevicaudarus (Engelm.) Fern. Short-tailed Rush Corailorhita cf: rnacrtlatn (Raf.) Raf. Spotted Coralroot Malaris monophyllos (L.) Sw. White Adder's-rnout h Pilea fontana (Lunnell) Rydberg Dark-seeded Clearweed Chrysospienium arnericanrtm Hooker Golden Saxifrage Ribes lacustre (Pers.) Poir. Bristly Black Currant Geum laciniatum Mumay Slashed Avens Potentifla arguta Pursh Ta11 Cinquefoil Rosa carolina L. Pasture Rose APPENDIX II - RARE NATIVE PLANTS OF JO-

Oxalis acetosellla L. Wood Sorrel Hypericum punctatum Lam. Dotted St. John's-wort Epilobium strictum Spreng. Downy Willowherb Oenothera perennis L. Sundrops Pamquinquijiolius L. American Ginseng Lechea intermedia Legg . Intermediate Pinweed Monotropa hypopithys L. Pinesap Chimuphila wnbellata (L.) Bartr. Pipsissewa Moneses uniflora (L.) Gray One-flowered Wintergreen Pyroia amencana S weet Round-Ieaved Pyrola ( P. rorundifolia var. americana) Gentiana andrewsii Griseb. Closed Gentian Gentianopsis crinita (Froel.) Ma Fringed Gentian Hydrophyllum canadense L. Canada Wate rleaf Verbena stricta Vent. Hoary Vervain Hedeoma hispida Pursh Mock Pennyroyal Galium circaerans Mic hx . Wild Licorice Galium lanceolatum Tor. Yellow Wild Licorice Galium tinctorium L. Dyer's Bedstraw Lonicera hirsuta Eaton Hairy Honeysuckle Vibumum cassinoides L. Wild Raisin Viburnum lantanoides Mic hx. Hobblebush ( V. alnifoliurn Marsh.) *RY Lobelia spicata Lam. Spiked Lobelia *Y Aster pilosus WiIld. Pringle's Aster *Y Aster urophyllus Lindl. Arrow-leaved Aster *Y Bidens vulgata Greene Ta11 Beggar's-ticks *Y Erigerorr pulchellus Michx. Robin's Plantain NPR Solidago arguta Ait. Sharp-leaved Goldenrod *Y Senecio aureus L. Golden Ragwort APPENDIX II - RwNATIVE PI-ANTS OF JOm'S

Birds of Joker's Hill, King Township, Regional Municipality of York C. Sean Blaney, July 1999 This tist is a compilation of 1997-99 observations of the author, P.M. Kotanen, W. Kilburn, R. Joos and M.T.Johnson and the observations of property manager William Fox from 1971 to the present. Al1 species on the main list were observed from within the Joker's Hill property boundaries. As this work was secondary to our main research only a low percentage of the species actually breeding on the site were recorded in the confirmed category. Almost al1 species in the possible (PO) and probable (P) breeding categories likely do breed on the site. The status codes listed below are a slightly modified version of those used in the Ontario Breeding Bird Atlas (Cadman et al. 1987): O - Observed without evidence of breeding M - observed only as a migrant or winter resideiit X - observed during the species' breeding season without evidence of breeding PO - breeding possible SH - observed in suitable habitat during breeding season SM - singing male observed in suitable habitat dunng breeding season P - breeding probable P -pair observed in suitable habitat during breeding season T - singing male observed in the same area on visits separated by at least two weeks A - agitated behaviour D - breeding display or intraspecies hostility N - nest building CO - breeding confirmed DD - distraction display NU - used nest AE - adult entering presumed nest site FS - adult carrying food or faecai sac NE- nest with eggs NY - nest with young FY - flightless or dependent young Common Loon Gavia irnrner (Brunnich) O-M Pied-billed Grebe Podilyrnbus podiceps (Linnaeus) O-M Arnerican Bittern Botaurus [enriginosus (Racken) O-M Great Blue Heron Ardea herodias Linnaeus O-X Green Heron Butorides striatus (Linnaeus) O-X Canada Goose Branra canadensis (Linnaeus) P-P Wood Duck Aix sponsa (Linnaeus) P-P Green-winged Teal Anas crecca Linnaeus O-M Mallard Anas platyrhynchos Linnaeus P-P Blue-winged Teal Anas discors Linnaeus O-M Ring-necked Duck Aythya collaris (Donovan) O-M Bufflehead Bucephala albeola (Linnaeus) O-M Hooded Merganser Lophodytes cucullatus (Linnaeus) O-M Common Merganser Mergus merganser Linnaeus O-M Turkey Vulture Cathartes aura (Linnaeus) O-X Northem Hanier Circus cyaneus (Linnaeus) O-X Sharp-shinned Hawk Accipiter srriatus Vieillot PO-SH Cooper's Hawk Accipiter cooperii (Bonaparte) CO-FS Broad-winged Hawk Buteo platyptems (Vieillot) P-T Red-shouldered hawk Buteo lineatus (Gmelin) CO-NY Red-tailed Hawk Buteo jamaicensis (Gmelin) P- A Ametican Kestrel Falco sparverius Linnaeus PO-SH Ruffed Grouse Bonasa umbellanis (Linnaeus) P-T Wild Turkey Meleugris gallopavo Linnaeus CO-FY American Coot Fulica nmericana Gmelin O-M Killdeer Chracirius vociferus Linnaeus P-T Solitary Sandpiper Tringa solitaria Wilson O-M Spotted Sandpiper Actitis macula ria (L innaeus) PO-SH Common Snipe Gallinago gallinago (Linnaeus) P-T American Woodcock Scolopav mirtor Gme lin PO-S H Ring-billed Gu11 Larus delawarensis Ord O-X Hening Gull Lnnis argenteus Pontoppidan O-X Rock Dove Columba livia G rnel in CO-AE Mourning Dove ïenaida macroura (Linnaeus) P-T Black-billed Cuckoo Coccy:rrs erythropthalmus (Linnaeus) P-T Eastern Screech-Owl Otus asio (Linnaeus) P-T Great Horned Owl Bitbu virginianrc Grnetin P-T Barred Owl Strix varia Barton P-T Snowy Owl Nyctclea scaridiaca (Linnaeus) O-M Common Nighthawk Chortieiles minor (Forster) O-X Whip-poor-will Caprimulgus vociferus Wilson PO-SM Ruby-throated Hummingbird Archiloclirls colrrbris (Linnaeus) P-T Belted Kingfisher Ceryle alcyon (Linnaeus) O-X Yellow-bellied Sapsucker Spltyrapiclrs wrius ( Linnaeus) CO-AE Downy Woodpecker Picoides pirbescens (Linnaeus) P-P Hniry Woodpecker Picoides villosus (Lin naeus) CO-NY Northern Flicker Colaptes auratus (Linnaeus) CO-ET Pileated Woodpecker Drycopus pileutus (Li nnaeus) P-T Olive-sided Flycatcher Coritopirs borealis (Swainson) O-M Eastern Wood-Pewee Contoprrs virens (Linnaeus) P-D Yellow-bellied Flycatcher Empidonaxj7aviventris (Baird and Baird) O-M Alder Flycatcher Empidonar alnorrrm Brewster P-T Least Flycatcher Empidortcrx minimus (Baird and Baird) P-T hstern Phoebe Sayornis phoebe (Latham) P-P Great Crested Flycatcher Myiarcltrcs crinitus (Linnaeus) P-D Eastern Kingbird Tyrannits tyrnnnus (Linnaeus) CO-NE Horned Lark Erernophila alpestris (Linnaeus) PO-SM Purple Martin Progrte subis (Linnaeus) O-X Tree Swallow Tachjrineta bicolor (Vieil lot) P-T Northern Rough-winged Swallow Stelgidopteryx serripennis (Audubon) O-X Bank Swallow Riparicr riparia (Linnaeus) O-X Cliff Swailow Hirundo pyrronota Viei Ilot O-X Barn Swallow Hinrndo rusticci Linnaeus CO-NY Blue Jay Cyanocirta cristata (Linn aeus) CO-FY American Crow Corvus brcrchyrhynchos Brehm CO-FY Blac k-capped Chickadee Parus atricapillus Linnaeus CO-FY Red-breasted Nuthatc h Sitta canadensis Linnaeus CO-FY White-breasted Nuthatch Sitta carolinensis Latham CO-FY Brown Creeper Cenhia americana Bonaparte P-T House Wren Troglodytes aedort Vieillot CO-FY Winter Wren Troglodytes trodglodytes (Linnaeus) P-T Golden-crowned Kinglet Regrtlrrs sarrapa Lichtenstein P-T Ruby-crowned Kinglet Regulus calendula (Linnaeus) O-M Eastern Bluebird Sialia sialis (Linnaeus) PO-SH Veery Catharusfrrscescens (Stephens) P-T Hennit Thrush Catharus guttatus (Pallas) O-M Wood Thnish Hyfocichla mustelina (Gmelin) P-T American Robin Turdus migratorius Linnaeus CO-FS Gray Catbird Dumetella carolinensis (Linnaeus) P-T Brown Thrasher Toxostoma rufitm (Linnaeus) PO-SM American Pipit Anthus rubescens (Tunstall) O-M Cedar Waxwing Bombycilla cedrorum Vieillot P-P Bohemian Waxwing Bombycilla garruius Vieillot O-M European Starling Sturnus vulgaris Linnaeus CO-NY Solitary Vireo Vireo solitarius (Wilson) P-T Warbling Vireo Vireo gilvus (Vieillot) P-T Philadclphia Vireo Vireo philodelphicm (Cassin ) O-M Red-eyed Vireo Vireo olivaceus (Linnaeus) CO-FS Blue-winged Warbler Vennivora pinus (Linnaeus) CO-FS Golden-winged Warbler Vemivora chrysoptera (Linnaeus) CO-FS' "Brewster's" Warbler Vennivora chrysoptera (Linnaeus) x CO-FS' (Golden-winged x Blue-winged Warbler) Vennivora pinus (Linnaeus) Tennessee Warbler Vemivora peregrina (Wilson) O-M Orange-crowned Warbler Vermivora celata (Say) O-M Nashville Warbler Vennivora nrficapilla (Wilson) P-N Nonhem Panila Parula nrnericana (Linnaeus) O-M Yellow Warbler Dendroica petechia (Linnaeus) P-P Chestnut-sided Warbler Dendroica pensylvonica (Linnaeus) PO-SM Magnolia Warbler Dendroica magnolia (Wilson) P-T Cape May Warbler Dendroicn tigrina (Grnelin) O-M Black-throated Blue Warbler Dendroictz caerulescens (Grnelin) O-M Yellow-rumped Warbler Dendroica coronata (Linnaeus) P-T Black-throilted Green Warbler Dendroica virens (Grnelin) P-T Blackbumian Warbler Dendroica fusca (Muller) P-T Pine Warbler Dendroiccz pinus (Wilson) P-T Palm Warbler Dendroica palmarrrrn (Grnelin) O-M Bay-breasted Warbler Dendroica castanea (Wilson) O-M Blackpoll Warbler Dendroict! striata (Forster) O-M Black-and-white Warbler Mniotiltn varia (Linnaeus) PO-SM American Redstart Setophaga rutacilla (Linnaeus) O-M Ovenbird Seiurus nrrrocapillrrs (Linnaeus) CO-FY Nonhem Waterthrush Seittnrs noveboracensis (Gmelin) PO-SM Mourning Warbler Opororrzis philadelphia (Wilson) P-T Common Yellowthroat Geothlypis trichas (Linnaeus) CO-FS Hooded Warbler Wilsonicr citrina (Boddaert) O-M Wilson's Warbler Wilsonia prrsilla (Wilson) O-M Canada Warbler Wilsonia canadensis (Linnaeus) PO-SM Scarlet Tanager Pirangn olivacea (Gmelin) CO-FY Northem Cardinal Cardinalis cardinalis (Linnaeus) P-T Rose-breasted Grosbeak Pheucticus ludovicianus (Linnaeus) P-T Indigo Bunting Pizsserina cyanea (Linnaeus) CO-FY Rufous-sided Towhee Pipilo erythopthalmus (Linnaeus) P-T American Tree Sparrow Spizella arborea (Wilson) O-M Chipping Spmow Spizella passerina (Bechstein) CO-FY Field Sparrow Spizella pusilla (Wilson) CO-NE Vesper Sparrow Pooecetes gramineus (Grnelin) PO-SH Savannah Sparrow Passerculus sandwichensis (Gmel in) CO-FS Grasshopper Sparrow Amniodramus savannumm (Grnelin) O-M Fox Sparrow Passerella iliaca (Merrem) O-M Song Sparrow Mefospiza nielodia (Wilson) CO-NE Swamp Sparrow Melospiza georgiana (Latham) P-T White-throated Sparrow Zoriotrichia albicollis (Grnelin) P-T Dark-eyed Junco Junco hyemalis (Linnaeus) O-M Snow Bunting Plectrophenax nivalis (Linnaeus) O-M Bobolink Dolichonyx oryzivorus (Linnaeus) P-T

' A male Brewster's Warbler paired with a female Golden-winged Warbler were seen together sevenl times betwetn late May and late June 1998, when the pair was observed carrying food and exhibiting agitated behaviour. Red-winged Blackbird Agelaius phoeniceus (Linnaeus) P- A Eastern Meadowlark Stumella magna (Linnaeus) P-T Rusty Blackbird Euphagrts carolinus (Muller) O-M Common Grackle Quiscalus quiscula (Linnaeus) CO-FS Brown-headed Cowbird Molothrus atcr (Boddaert) P-P Northern Oriole lcterus galbula (Linnaeus) P-T Pine Grosbeak Pinicola enucleator (Linnaeus) O-M Purple Finch Carpodacus purpureus (Grnelin) P-P House Finch Carpodacus mexicanur (Muller) P-T Red Crossbill Loxia curvirostra Linnaeus O-X White-winged Crossbill Loxia lerrcoptera Gmel in O-X Common Redpoll CardeulisJkrmmea (Linnaeus) O-M Pine Siskin Cardeulis pinus (Wilson) O-M American Goldfinch Carduelis tristis (Linnaeus) CO-NE Evening Grosbeak Coccoth rausres vespertinus (Cooper) O-M House Sparrow Passer domesticus (Linnaeus) O-X

Clay-coloured Sparrow Spitella pallida (Swainson) - observed just outside property boundaries, to the northwest Mammals of Joker's Hill, King Township, Regionai Municipality of York C.S. Blaney and W. Fox, 1998 The following list includes al1 wild mammals observed by property manager William Fox between 197 1 and 1999, as well as those recorded dunng field work in 1997 and 1998 and those recovered in small mammal trapping in 1999 (P.M. Kotanen, unpublished data). Ali observations were incidental ones made during other work. A systematic program of nocturnal bat detection would undoubtedly reveal a nurnber of additional species. Virginiz Opossum and Beaver were observed just north of the property boundary. Dùielphimomhia O~ossums Didelphis virginiana Virginia Opossum

Insectivora Shrews and Moles Blarina brevicaudara Short-tailed Shrew Sorex cinereus Masked Shrew Condylura crisrata Star-nased Mole Chiro~tera Bats C-Eptesicus ~USCUS Big Brown Bat (indentification probable only) La~ornomha Rabbits and Hares Syl vilagus floridana Eastern Cottontail Lepus europaeirs European Hare Rodeniia Rodents Tamias stria rus Eastern Chipmunk Marmota monax Woodchuck Sciurus carolinensis Gray Squirrel Tarniasciurus hudsorlicus Red Squirrel Glaucomys sp. flying squirrel sp. Castor canadensis Beaver Zapus hudsonius Meadow Jumping-mouse Peromyscus leucopus White-footed Mouse Microtus pennsylvanicus Meadow Vole Ondatra ziberhicus Muskrat Rattus norvegicus Norway Rat Mus musculus House Mouse Erithizon dorsatum Porcupine Carnivora Carnivores Canis latrans Coyote Vulpes vulpes Red Fox Procyon lotor Raccoon Mustela ermina Ermine Mustela vison Mink Mephiris mephitis Striped Skunk &îiodacîyia Deer Odocoileus virginianus White-tailed Deer APPENDIX V Amphibians and Reptiles of Joker's Hill, King Township, Regional Municipality of York C. Sean Blaney, 1999. The following species were recorded during in 1997 or 1999 by C.S. Blaney, and P.M. Kotanen, or by property manager William Fox between 1971 and the present. AMPHIBIANS Ambystomatidae Mole Salamanders Arnbystorna macvlatum Spotted Salamander Salamandridae Newts Notopthalmus viridescens Red-spotted Newt Pletitodontidne Lungless Salamanders Phhodort cinereus Red-backed SaIamander Hy Iidae Treefrogs Pserrdacris crucifer Spring Peeper Hyla versicolor Gray Treefrog Ranidae Tme Frogs Rana catesbiana Bull Frog Rana clamitans Green Frog Rnna pipiens Leopard Frog Rana sylvatica Wood Frog Bufonidae Toads Brlfo americana American Toad REPTILES Chelydridae Snapping Turtles Chelyra serperitina Snapping Turtle Enry didae Box and Water Turtles Chrysernys picta Painted Turtle Colubtùiae Colubrid Snakes Thamnophis sirtalis Garter Snake Storeria occipitornaculata Red-bellied Snake Diadophus punctatus Ring-necked Snake