ASSESSING THE RESPONSE OF SMALL MAMMAL FUNCTIONAL GUILDS TO A SIMULATED PATHOGEN ATTACK IN A DECIDUOUS FOREST ECOSYSTEM

Oak trees (Quercus species) are a foundation species that influence the population dynamics of other organisms by stabilizing ecosystem processes. Globally, oak-dominated forests have experienced widespread mortality due to the fungal pathogen, Phytophthora ramorum, which causes the disease Sudden Oak Death (SOD). I investigated the impact of a simulated pathogen attack such as SOD on the small mammal assemblage of an oak forest in Cornwall, New York. Specifically, I tested the hypothesis that specialist species are most impacted by the loss of foundation species and that they would decline in abundance because of changes in food and habitat resources. In 2008, oaks were girdled to cause mortality and mimic the symptoms of SOD. Four treatments were established, with three replicates of each: 100% oaks girdled, 50% oaks girdled, 100% non-oaks girdled, and control. From 2008 to 2012, small mammals were live captured, individually marked, and released in each of the four treatments. In addition, environmental variables hypothesized to influence small mammal abundance were collected, including coarse woody debris, leaf fall, canopy openness, soil moisture and temperature. Six small mammal species were captured, resulting in 5,135 total small mammal capture events. A total of 576 white-footed mice (Peromyscus leucopus) and 412 eastern chipmunks (Tamias striatus) were captured. These two species composed more than 97% of all animals captured. Small mammal species diversity, as measured by Shannon-Wiener diversity index, did not differ by treatment across years, but diversity was significantly lower in 2011 and 2012 across treatments. Decreased species diversity in the fourth and fifth years after treatment suggests that the small mammal assemblage, specifically the resource specialist species, may be negatively impacted by landscape-level forest disturbances. Full likelihood closed capture models indicated that abundance of the generalist white-footed mice and eastern chipmunks as well as their capture and recapture probabilities were not driven by the treatment conditions. Abundance did significantly vary by year for both white-footed mice and eastern chipmunks. White-footed mouse abundance was significantly higher in 2011and 2012 than all other years. Eastern chipmunk abundance was significantly higher in 2009 and 2012 and significantly lower in 2011. Northern short-tailed shrew (Blarina brevicauda) abundance significantly varied by year, but not treatment. Northern short-tailed shrew abundance was significantly higher in 2008 and 2009 compared to 2010-2012. Red-backed vole (Clethrionomys gapperi) abundance did not significantly differ by year, but it was significantly higher on control and 100% non-oak girdled plots compared to 50% oak girdled and 100% oak girdled plots. Meadow vole (Microtus pennsylvanicus) abundance varied significantly by year, but not by treatment, with abundance significantly higher in 2009 compared to all other years of the study. Environmental conditions significantly varied by treatment, with coarse woody debris and soil moisture being greater in 100% oak and 50% oak girdled treatments. These habitat changes did not appear, however, to impact the generalist small mammal species. Relationships between these measured environmental variables and small mammal abundance did not follow expected patterns, which may have been due to the relatively short duration of the study. Based on my findings and due to their sensitivity to the altered environmental conditions, resource specialists such as northern short-tailed shrews and red-backed voles may be more appropriate biological indicators of ecosystem health following large-scale forest disturbance events. As the movement of pathogens globally accelerates, it will be increasingly important for ecologists to understand the bottom-up cascade of impacts related to the loss of foundation tree species

The Grizzly, April 13, 2006

Relay a Success • New Healthcare Scholarship Available • Lurking Beneath the Skin: Scabies Infection • Day of Museums • Shopping with Eco-labels • Airband a Hit • Opinions: Drawing the Line: Moral Predicament of Abortion, Part II • Importance of CoSA: A Message • Bears Battle Back • Real Deal on Steroidshttps://digitalcommons.ursinus.edu/grizzlynews/1712/thumbnail.jp

The Grizzly, February 16, 2006

Hoodoo Man Arthur Flowers Delivers Captivating Speech at Ursinus • USGA Holds First Meeting of Semester • Francophone Film Festival: Almost Peaceful • Georgetown Professor to Lecture at Ursinus • Getting to Know Your Glands • Spiritual Experiences in Paris • Meet the New Director of Facilities Services and Keep Current with Bomberger Renovations • Recycling Myths Revealed • Retraction on Parking Article • Broken Social Scene a Must Have for Indie Fans • Lone Senior Walks Off a Winnerhttps://digitalcommons.ursinus.edu/grizzlynews/1706/thumbnail.jp

The Grizzly, March 9, 2006

Two Juniors Attend C.O.O.L. Idealist National Conference in Tennessee • Celebration of Student Achievement • SPINT: Overview of House Projects • Understanding Abortion • Imperfect World of Auguste Rodin • Kelly Stirs Up Laughs • Marche aux Puces and Other Shopping Advice • Opinions: Letter to the Editor; Gimme Fiction Drips with Musical Ambition; Line Between Personal Offense and Free Speech • Bears Crush Crusaders • Respect!https://digitalcommons.ursinus.edu/grizzlynews/1709/thumbnail.jp

The Grizzly, February 2, 2006

New Member Education Begins Another Season at Ursinus • What Happened to the Kreme? • CAB\u27s Events in the Spring of 2006 • Bomberger Cam • Sigma Xi Lecture at Olin • Virginity Vexing • Dancer and Cultural Historian to Speak at Ursinus • Pre-departure Paris • Ursinus Gets Greener by Doing More than Landscaping • Dealing with Stress • Opinions: There are no Maids Here; Return of Open Mic Night; The New Pornographers Break Through with Twin Cinema • Bears Veto Diplomats • Daley\u27s Lay-up Beats Diplomatshttps://digitalcommons.ursinus.edu/grizzlynews/1704/thumbnail.jp

The Grizzly, February 23, 2006

Possibility of Honor Code Comes Under Review Again at Ursinus • Date Auction Raises Money for Airband Charity • WVOU: Preview of the Semester\u27s Events • Countdown to Relay Continues • Batteries Included • Airband Begins a Successful Year • A Vitamin a Day Keeps the Doctor Away • Kwan Bows out of Olympics • Opinions: How Did You Celebrate Black History Month?; Apple Twists Unexpected in Extraordinary Machine • Crown Hopes for Royal Family • History Made as Bears Win 4th CC Titlehttps://digitalcommons.ursinus.edu/grizzlynews/1707/thumbnail.jp

The Grizzly, April 12, 2007

Project Pericles Continues to Succeed in Community Service • Macs Lag in Environmental Friendliness According to Greenpeace • New Dorm Progress • Ursinus Freshmen Fall Behind in Collegiate Learning Assessment • Spread Your Legs and Turn Your Head and Cough • Relay for Life Fast Approaching • Ursinus, Break the Silence! • Nutrition Tips: Veggie Report • Opinions: Dear Mahmoud • Bears Terrorize McDaniel, Sit Atop CC Standings • Bears Finish Second at NCGA Championshipshttps://digitalcommons.ursinus.edu/grizzlynews/1737/thumbnail.jp

The Grizzly, March 2, 2006

Omega Chi Hosts Red Cross Blood Drive • Alumna of Sigma Gamma Rho Honored with Stamp • Georgetown Professor Speaks About Abortion • Ursinus Hosts Job and Internship Fair • Introducing the IUD • Centre Pompidou: Modern Art • Breaking Stereotypes • WVOU Spotlight: Bloc Party • Opinions: Red Cross Guidelines Demonstrate Questionable Requirements • Letter to the Editor • Is the Juice Worth the Squeeze?https://digitalcommons.ursinus.edu/grizzlynews/1708/thumbnail.jp

The Grizzly, February 9, 2006

Preview of Black History Month at Ursinus • Wellness Center Relocated • Higher Education Lobbyist to Speak • Relay for Life Kick-off Exhibits Large Turnout and Hope for Event • Scents and Sensibility • Le Metropolitan • Rodin Curator to Lecture • Residence Life Creates Exciting New Housing Options • Monkey Business Takes on a Whole New Meaning • Getting Around: Why Biking is Better • Opinions: Real Love, I\u27m Looking for Real Love; Many Faces of Beck; Fighting for a Spot: The Pains of Parking on Campus • Dynasty! 20 Straight CC Winshttps://digitalcommons.ursinus.edu/grizzlynews/1705/thumbnail.jp

The Grizzly, December 8, 2005

Bomberger Gets a Face Lift • Ursinus Remembers Rosa Parks • Holiday Spotlight: Materialism vs. Family • Music to Celebrate By • It\u27s Spoken Word, Haven\u27t You Heard? • First Ever Ursinus College Bear Olympics Meets with Success • Holiday Fashion: What not to Wear • Misconceptions About Feminine Hygiene • Ursinus Professor Directs Performance at Prince Music Theater • Opinions: A Politically Correct Holiday Season; Flakes of Fury; Blog Addiction • Bears Beat at Buzzer • Guntli Leads Bears Past Bulletshttps://digitalcommons.ursinus.edu/grizzlynews/1702/thumbnail.jp