THE PAPER SHOULD BE A MAXIMUM OF 5 PAGES (double-spaced; Times New Roman 12 font), excluding the title page and literature cited.
First (title) page must include:
1.
Descriptive title
2.
Author
3.
Abstract (NOTE: MAXIMUM 200 WORDS)
Abstract: Does the abstract reflect the title of the project and the aim and scope of the work?
Does it contain essential information on rationale, hypothesis, study system and significance? Is it written clearly? (10 points)
EFFECTS OF THE INVASIVE ARGENTINE ANT ON RODENTS AND PLANT SPECIES
COMPOSITION IN COASTAL SAGE SCRUB HABITAT
Name
Abstract
In the coastal sage scrub (CSS) habitat of southern California, granivorous native ants and rodents are important dispersers of seeds. Whereas rodents cache and predate the large seeds of exotic grasses, native ants disperse the small seeds of native shrubs. Where the invasive
Argentine ant is introduced into CSS habitat, it competitively displaces native ants. If the
Argentine ant prefers eating large seeds to small seeds, it may compete with rodents for food resources. Furthermore, changes in dispersal dynamics caused by the displacement of native ants by the Argentine ant, as well as any subsequent competition with rodents for food resources, may lead to changes in CSS plant species composition. In this study I will use combinations of rodent exclosures and ant repellant to establish sites with 1) Argentine ants only, 2) rodents only,
3) Argentine ants and rodents, and 4) no Argentine ants or rodents. To examine whether
Argentine ants compete with rodents for food resources, I will test for increases in abundance in each taxa where the other is removed. Additionally, I will survey vegetation on all sites before and after prescribed fires to examine how Argentine ant and rodent presence affects CSS plant species composition.

Introduction: Does the introduction start by introducing a significant question in community ecology? Are statements supported by appropriate citations from published literature? Is the initial question refined through the introduction to statement of the objective of the study? (10 points)
Introduction
The Argentine ant ( Linepithema humile ), which was first observed in California in 1905, has rapidly spread throughout the state, following human disturbances (Suarez and Case 2003).
The Argentine ant thrives in moist habitats, but is able to invade 50 to 100 m into dry coastal sage scrub (CSS) habitat along urban edges and riparian corridors (Holway 2005). Where it invades, the Argentine ant displaces native ant species, either reducing or eliminating native ant diversity (Suarez et al. 1998). Whereas native ant species disperse small seeds of native shrubs
(< 2 mm in length) in CSS habitat, the Argentine ant typically does not (Carney et al. 2003).
Instead, the Argentine ant likely prefers eating the large seeds of exotic grasses (> 1 cm in length) present in CSS habitat (J. Duggan, pers. obs.). Rodents in scrub habitats also prefer large grass seeds to small shrub seeds (Meserve 1976) and thus, may compete with the Argentine ant for food resources where the Argentine ant is present. Furthermore, changes in dispersal dynamics caused by the displacement of native ants by the Argentine ant, as well as any subsequent competition with rodents for food resources, may lead to changes in CSS plant species composition. In this study I will test (1) whether Argentine ants compete with native
CSS rodents for food resources and (2) if invasion by the Argentine ant leads to changes in CSS plant species composition

Hypotheses and predictions: Are the hypotheses presented clearly related to the objective of the study and are they logically connected to the ideas presented in the introduction? Are hypothesis stated correctly (i.e., do they provide an explanation for an observation)? Are predictions logically connected to the hypotheses? Are alternatives to the primary hypothesis acknowledged
(where appropriate)? (10 points)
Hypotheses and Predictions
In this study I will examine 2 hypotheses. First, I will test whether Argentine ants compete with native coastal sage scrub (CSS) rodents for food resources. If Argentine ants compete with CSS rodents for food resources, I expect either/both taxa to increase in abundance in areas where the other is removed. To test this hypothesis, I will compare ant and rodent abundance between the following treatments: (1) Argentine ants only, (2) rodents only, and (3)
Argentine ants and rodents. Alternative hypotheses explaining any differences in abundances between treatments seem unlikely. Argentine ants and CSS rodents do not share any major predators or parasites and do not prey on one another. Additionally, while the 2 taxa may experience some competition for nest sites, Argentine ants likely prefer sites with high moisture levels near urban edges, whereas rodents instead prefer sites with high levels of vegetation cover further from urban edges.
Second, I will test whether invasion by the Argentine ant leads to changes in CSS plant species composition. To test this hypothesis, I propose conducting prescribed burns within treatments after 2 years of initial rodent, ant, and vegetation sampling. Seedling recruitment is typically rare/slow in CSS habitat until space resources are made available by disturbances such as fire (Keeley and Keeley 1999). Thus, prescribed burns will allow rapid seedling recruitment from seed banks modified by rodent and Argentine ant interactions. Because plant species composition may continue changing for many years after prescribed burns, I propose at least 3 years of post-fire rodent, ant, and vegetation sampling.

I hypothesize a decrease in native shrub seed dispersal caused by the displacement of native ant species by the Argentine ant will lead to decreased native shrub cover and increased exotic plant cover in the “Argentine ants only” treatment. Additionally, I expect a decrease in native shrub seed dispersal caused by the exclusion of native ant species, combined with rodent predation on exotic grass seeds in the “rodents only” treatment, will lead to decreased native shrub cover, as well as a slight increase in exotic cover (i.e., less than found in the “Argentine ants only treatment”). Furthermore, I hypothesize in the “Argentine ants and rodents” treatment, a decrease in native shrub seed dispersal caused by the displacement of native ant species, combined with rodent and Argentine ant predation on exotic grass seeds, will lead to decreased native shrub cover and a slight increase in exotic cover (i.e., even less than found in the “rodent only” treatment). Alternatively, the combined predation on exotic grass seeds by Argentine ants and CSS rodents could be strong enough to exclude exotic grasses and allow an increase in native shrub cover within the “Argentine ants and rodents” treatment.
Lastly, I propose constructing a 4 th
treatment with no Argentine ants or rodents and I hypothesize the absence of both shrub seed dispersal and predation on exotic grass seeds will lead to a decrease in native shrub cover and an increase in exotic cover greater than that within any other treatment. Alternative hypotheses explaining any differences in plant species composition between treatments seem unlikely. Insecticides used to remove Argentine ants from
“rodents only” and “no Argentine ants or rodents” treatments might decrease non-ant insect herbivores on CSS plants, however, Mills (1983) found non-ant insect herbivores had little effect on post-fire chaparral (a shrubland habitat similar to CSS) plant species composition.

Study area and organisms: Is necessary background information on the ecology/natural history of study organisms and the study site presented? Is there unnecessary/irrelevant information that could have been omitted? Is the choice of organism/study site appropriate given the objective of the study? (10 points)
Study Area and Organisms
Coastal sage scrub (CSS) occurs in southern California and northern Baja California on coastal terraces and foothills below 600 m (O’Leary 1990). The area is characterized by a
Mediterranean-type climate, with long, dry summers and cool, wet winters (Keeley and Keeley
1999). Due to displacement by agriculture and urbanization, CSS habitat is considered one of the most endangered plant communities in the United States (Westman 1987). Researchers estimate only 10-44% of the original extent of CSS habitat remains intact (O’Leary 1995).
While much CSS habitat has been lost to agriculture and urbanization, invasion by exotic species is increasingly threatening CSS biodiversity. Severe disturbances associated with urban and agricultural activities facilitate invasion of exotic grasses and forbs into CSS habitat (Stylinski and Allen 1999). Once established, exotic grasses and forbs compete effectively with native plant species, slowing recolonization by native shrubs (O’Leary 1995). Due to habitat loss and invasion by exotic species, nearly 100 species of plants and animals either obligately or facultatively associated with CSS habitat are now classified as rare, sensitive, threatened, or endangered by federal and state agencies (O'Leary 1995).

Methods and Experimental Design: Is the explanation of the methods clear (use figures if necessary)? Are the methods appropriate to test the hypothesis proposed? Are essential methodological details included? This might include, for example, replication of treatments, size of treatments, duration of experiment, description of independent and dependent variables. Has the author considered potential confounding effects that might interfere with the ability to test the hypothesis? Are these recognized/addressed (where possible)? (10 points)
Methods and Experimental Design
I will choose at least 4 coastal sage scrub (CSS) sites within 100 m of reserve edges where Argentine ants are detected and where levels of exotic grass invasion are similar (i.e. 20-
30% exotic grass cover). At each site I will establish four 50 x 50 m exclosures, each a different treatment. The 4 treatments will include: (1) Argentine ants only (rodent exclosures), (2) rodents only (exclosures with holes allowing free movement of rodents, as well as ant-repellant along perimeter of exclosures), (3) Argentine ants and rodents (exclosures with holes allowing free movement of rodents), and (4) no Argentine ants or rodents (exclosures with ant-repellant along perimeter of exclosures) (Figure 1). Exclosures will consist of hardware cloth fencing placed
0.25 m below ground within trenches and standing 1 m in height above ground.
After establishing exclosures, I will intensively trap and remove all rodents from the
“Argentine ant only” and “no Argentine ants or rodents” exclosures. I will remove ants from
“rodents only” and “no Argentine ants or rodents” exclosures using repeated applications of insecticide. Although Davidson et al (1985) found no adverse affects of insecticide on rodents; I will use rodent capture records to track fitness of individuals over time. Additionally, I will check for the presence of rodents and ants within exclosures monthly and will remove any invaders.
Using Sherman live-traps set in 5 x 5 grids at 5 m intervals, I will survey rodents within the rodent-only and Argentine ant + rodent treatments 4 times per year to estimate rodent abundance and reproduction. Traps will be checked for 5 consecutive days and during each

capture I will record date, location, species, body mass, sex, reproductive status, and a unique ID number. To estimate both native and Argentine ant abundance, I will sample ants 4 times per year using test tubes half-filled with non-toxic antifreeze set in the ground so tops are flush with the soil surface. Tubes will be placed in 5 x 5 grids at 5 m intervals within all treatments and will be left open for 5 days during each sampling session. At the end of each session, all ants will be taken to a lab and identified to species. I will sample vegetation each spring, using a point intercept method within each of the exclosures to estimate vegetation cover by species, origin (native or non-native), and growth form (shrub or herb) for each grid. I will estimate species richness for each grid by recording all unique species found alive and rooted within the grid area.
I will use a repeated measure ANOVA to test whether Argentine ant abundance differs between “Argentine ant-only” and “Argentine ant and rodent” treatments. This analysis will also test whether 1) Argentine ant abundance changes over time and 2) Argentine ant abundance changes differently over time (i.e. sampling session), depending on treatment. I will use the same method to test whether rodent abundance, reproductive activity, or body mass differs between “rodent only” and “Argentine ant and rodent” treatments or over time. Lastly, I will use additional repeated measure ANOVAs to examine how both native and exotic plant cover, as well as species richness, varies across treatments and sampling sessions.

Significance, originality and creativity of work: This is the justification statement for the project
– this does NOT mean just the conservation/management (i.e., applied) importance of your proposed work. I am looking here for a statement to indicate how this project can move the field of community ecology forward. Does this study potentially provide new insights into how communities are organized? Are the results from this study system broadly applicable to other groups of organisms or other kinds of interactions? What other studies might build on the results from this one – or would the results of this study allow you to infer something new about this system that you could then go on to test? (10 points)
Significance
The invasion of coastal sage scrub (CSS) habitat by the Argentine ant presents a unique opportunity for examining the role of competition in structuring granivorous communities in southern California. Ants are important components of many ecosystems and changes in native ant communities may affect multiple taxa (Brown and Davidson 1977, Brown and Munger 1985,
Suarez and Case 2003). However, studies examining the effects of the Argentine ant on non-ant taxa are rare (Bolger et al. 2000, Carney et al. 2003, Suarez et al. 2000, Suarez and Case 2002).
This study will gather much-needed information on the effects of the Argentine ant on (1) the
CSS rodent community and (2) the CSS plant community, as a whole. Understanding community-level responses of non-ant taxa to Argentine ant invasion will allow land managers to better assess invasion risks and more effectively allocate effort to prevent loss of biodiversity in CSS habitat.
Presentation and clarity: Are the different sections of the proposal well linked? Are the ideas presented clearly – and can they be followed from one section of the proposal to the next? Is the writing style clear (topic sentences introduce themes presented in each paragraph; concise language used; spelling and grammar acceptable)? Use of tense and active/passive voice is consistent? Note: Use the past tense to describe results found in previous studies; use future tense “we will…” to describe work that you propose to do. (5 points)

Literature Cited: Are the papers in the body of the proposal cited in here? Are the references cited here in the body of the text? Is consistent formatting used? (5 points)
Literature Cited
Bolger, D. T. Suarez, A. V., Crooks, K. R, Morrison, S. A., and T. J. Case. 2000. Arthropods in urban habitat fragments in southern California: area, age and edge effects. Ecological
Applications 10: 1230-1248
Brown, J. H., and D. W. Davidson. 1977. Competition between seed-eating rodents and ants in desert ecosystems. Science 196: 880-882.
Brown, J. H., and J. C. Munger. 1985. Experimental manipulation of a desert rodent community: food addition and species removal. Ecology 66: 1545-1563.
Carney, S. E., Byerley, M. B., and D. A. Holway. 2003. Invasive Argentine ants ( Linepithema humile ) do not replace native ants as seed dispersers of Dendromecon rigida
(Papaveraceae) in California, USA. Oecologia 135: 576-582.
Davidson, D. W., Samson, D. A., and R. S. Inouye. 1985. Granivory in the Chihauhaun desert: interactions within and between trophic levels. Ecology 66: 486-502.
Holway, D. H. 2005. Edge effects of an invasive species across a natural ecological boundary.
Biological Conservation 121: 561-567.
Keeley, J. E., and S. C. Keeley. 1999. Chaparral. Pages 203-254 in M. G. Barbour and W. D.
Billings (editors) North American Terrestrial Vegetation . Cambridge University Press,
Cambridge.
Meserve, P. L. 1976. Food relationships of a rodent fauna in a California coastal sage scrub community. Journal of Mammalogy 57: 300-319.
Mills, J. N. 1983. Herbivory and seedling establishment in post-fire southern California chaparral. Oecologia 60: 267-270.

O’Leary, J. F. 1990. California coastal sage scrub: general characteristics and considerations for biological conservation. Pages 24-41 in A. A. Schoenherr (editor) Endangered Plant
Communities of Southern California . Proceedings of the 15 th
Annual Symposium,
Southern California Botanists, Special Publication No. 3.
O’Leary, J. F. 1995. Coastal sage scrub: threats and current status. Fremontia 23: 27-31.
Stylinksi, C. D., and E. B. Allen. 1999. Lack of native species recovery following sever exotic disturbance in southern California shrublands. Journal of Applied Ecology 36: 544-554.
Suarez, A. V., Bolger, D. T., and T. J. Case. 1998. Effects of fragmentation and invasion on native ant communities in coastal southern California. Ecology 79: 2041-2056.
Suarez, A. V., Richmond, J. Q., and T. J. Case. 2000. Prey selection in horned lizards following the invasion of Argentine ants in southern California. Ecological Applications 10: 711-
725.
Suarez, A. V., and T. J. Case. 2002. Bottom-up effects on the persistence of a specialist predator: ant invasions and coastal horned lizards. Ecological Applications 12: 291-298.
Suarez, A. V., and T. J. Case. 2003. The ecological consequences of fragmentation mediated invasion: the Argentine ant, Linepithema humile , in southern California. Pages 161-180 in G.A. Bradshaw and P. Marquet (editors) How landscapes change: human disturbance and ecosystem disruptions in the Americas . Ecological Studies, vol. 162, Springer Verlag,
Berlin.
Westman, W. E. 1987. Implications of ecological theory for rare plant conservation in coastal sage scrub in Proceedings of the conference on Conservation and Management of Rare and Endangered Plants. California Native Plant Society, Sacramento, CA.

Figure 1. At each site, 4 treatments will be placed on reserve land adjacent to an urban edge.
Thick lines around “rodents only” and “ no ants or rodents” treatments indicate an ant repellant substance used to exclude Argentine ants. Ovals indicate holes permitting rodent access to
“rodents only” and “rodents and ants” treatments.