adirondack research consortium student symposium program with... · composition and structure in...

201 Paolozzi Center, Paul Smith’s College Campus, P.O. Box 96, Paul Smiths, NY 12970 [email protected], 518-327-6276

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Adirondack Research Consortium Better Information for Better Decisions

Student Research Symposium

Joan Weill Adirondack Library, Adirondack Room (2nd

Floor), Paul Smith’s College

April 13th

, 2013, 10:00 – 3:00

Sponsored by

Glenn and Carol Pearsall Adirondack Foundation

International Paper Foundation - Ticonderoga Mill

Program

10:00 Welcome and Introduction

10:10 “The Effect of Temperature and pH on the Growth of Variable-leaf Milfoil

(Myriophyllum heterophyllum)”

Author(s): Claire Baker and Michelle Berrus Paul Smith’s College

Advisor(s): Celia Evans and Daniel Kelting Undergraduate

10:30 “Extreme precipitation history, the NAO, and the Adirondacks”

Author(s): Sean Regalado and Martin Serwatka Paul Smith’s College

Advisor(s): Curt Stager Undergraduate

10:50 “Occupancy Modeling and Applications for Spruce Grouse (Falcipennis Canadensis) in the

Adirondacks”

Author(s): Kevin Ohol SUNY Potsdam

Advisor(s): Angelena Ross, NYS DEC, Professor: Kristen VanHooreweghe Undergraduate

11:10 “Visual Harmony: The Relationship Between the Built and Natural Environments From the

User’s Perspective”

Author(s): Nina L. Caruso Roger Williams University

Advisor(s): Jeremy Wells and Harvey H. Kaiser Graduate

11:50 POSTER: “Resident evaluations of community satisfaction in five Adirondack towns”

Author(s): Christopher Shrope and David Pynchon St. Lawrence University

Advisor(s): Erik A. Backlund Undergraduate

12:00 Lunch

1:30 “Black capped Chickadee feeding behavior: Interactions of food quality and distance from

protective cover”

Author(s): Jenna Daub Paul Smith’s College

Advisor(s): Jorie Favreau Undergraduate


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1:50 “Assessing the impact of North American porcupine (Erethizon dorsatum) foraging on forest

composition and structure in northern New York”

Author(s): Erin Siracusa St. Lawrence University

Advisor(s): Erika Barthelmess Undergraduate

2:10 “Variation in litter decomposition between native speckled alder and non-native European

buckthorn: an experimental study in Plattsburgh, NY”

Author(s): Kali M. Blankenship SUNY Plattsburgh

Advisor(s): Rachel E. Schultz Undergraduate

2:30 WORKSHOP: “Publishing Research”, Rebecca Steinberg, Executive Editor, Adirondack Journal

of Environmental Studies

3:00 ADJOURN

2013 Participating Colleges

COMING THIS MAY!

20th

Annual Conference on the Adirondacks

20/20- A Retrospective Look Back 20-Years, Today, and 20-Years in the

Future Climate Change/ Sustainability and Communities/ Energy/ Wilderness and Working

Landscapes/Wildlife and Ecological Trends

May 15-16, 2013, High Peaks Resort, Lake Placid, NY Media Sponsor – Mountain Lake PBS, WCFE, Plattsburgh, NY

Featuring Andy Revkin of the New York Times

More information: http://www.adkresearch.org/conference/

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PAPER ABSTRACTS (In order of presentation)

“The Effect of Temperature and pH on the Growth

of Variable-leaf Milfoil (Myriophyllum heterophyllum)”

Authors: Claire Baker, Michelle Berrus, Celia Evans and Daniel Kelting

Paul Smith’s College

A fundamental part of invasion biology is the prediction of the potential spread of invasive

species. This is due to the negative ecological, economic and human-health effects that invasive species

may cause. Variable-leaf Milfoil (Myriophyllum heterophyllum), a newly listed invasive species to the

Northeast (since 2009), is native to southern U.S. states from Florida to New Mexico, and has since

spread to North Dakota and southwestern Quebec, without becoming invasive to those areas. Variable-

leaf Milfoil (VLM) is spreading in the Adirondack Park in Northern New York, and its invasive potential

is unknown. Based on the geographic distribution of native VLM in some warmer lakes with alkaline

waters, it is reasonable to hypothesize that increased temperature, predicted by current climate change

models, combined with a low pH in Adirondack lakes would likely increase the growth of VLM.

This study examines whether temperature and pH have an effect on the growth of VLM. In this

laboratory experiment, the growth of 80 VLM fragments were examined in warm (33.1275°C) and cool

(23.135°C) temperatures, combined with 10 pH treatments. Contrary to our hypotheses, there was no

significant effect of pH on VLM growth or biomass allocation. Due to unexpected buffering of the lake

water, there was a high degree of variability in pH within a pH treatment. Variance in average pH

increased with acidity of the treatments, which may have made it difficult to see significant differences

due to pH.

The total biomass growth and allocation to lateral growth were significantly greater in the cool

water treatment than the warm water treatment (Figure 1). Conducting the experiment in a laboratory

without the aid of refrigeration resulted in the cool treatment being ‘room temperature’ and the warm

treatment approaching the maximum temperature reported for the waters in Florida where VLM is native.

While this scenario seems fairly extreme for aquatic plants adapted to Adirondack lakes, it is within the

range of habitat variables that VLM is exposed to in other parts of its geographic distribution. Given

predicted increases in Adirondack water temperatures, a scenario in which lakes would experience

temperatures in the range of 30 to 35oC is not out of the question. Because all experimental containers

were constantly aerated, we are confident that results of temperature treatments were not confounded with

the negative effect of increased temperature on the availability of dissolved oxygen.


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Studies have shown that stress and associated growth responses of macrophytes in warming waters

will be species specific. In a 6-week laboratory experiment where strands are placed immediately into a

much warmer environment than the one from which they were collected, acclimation over seasons and

adaptation over generations were not taken into account, nor were the responses of the non-invasive

competitors. Therefore, in plant communities or relative competitive status of VLM due to warming water

is unknown. We can conclude from our data, however, that VLM vigor is relatively unaffected by pH, but

is reduced by water temperatures in the upper range of what might be expected under a climate change

warming scenario.

Figure 1: Average biomass growth of Variable-leaf Milfoil (Myriophyllum heterophyllum) experimental strands in cold water

(23.135°C) and warm water (33.1275°C) for a total of 6 weeks in the months of July and August, 2012. The bars on the graph

represent +/- 1 standard error (n=40 for each temperature treatment).


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Extreme precipitation history, the NAO, and the Adirondacks

Sean Regalado and Martin Serwatka

Curt Stager, major professor

The extreme precipitation events of recent years have increased interest in the nature and causes of such

events in the North Country, and have raised questions about what a warmer future may bring in that

regard. At present, most regional climate models anticipate wetter conditions by the end of this century,

but a few of them anticipate drier conditions instead. In this situation, environmental history may provide

unique and valuable insights into present and future climate variability. To reconstruct long-term

precipitation variability in the region, a 160 cm piston sediment core was collected from Lost Pond, in

Franklin County, NY. This pond lies within an isolated depression with no outlet, which allows it to rise

freely during wet periods. The relative abundance of planktonic and benthic diatoms was determined at 1

cm intervals and wetter climates were inferred from high percentages of planktonic taxa. Radiocarbon

dating of a sediment sample from the base of the core produced a tentative chronology for the past

millennium. If the chronology is accurate and patterns of change in the diatom record are supported by

future analyses, then our study shows that abrupt, extreme wet events were common during the last

millennium. We also find that wetter conditions were associated with negative states of the North

Atlantic Oscillation, the opposite of what is widely reported on the basis of recent observational records.

Precipitation was negatively correlated with temperature during the cool Little Ice Age and warm

Medieval Climate Anomaly, again in opposition to most model projections. With temperatures in the

Northeast projected to increase by 2-5 degrees C by 2100 AD, our study suggests the region may become

more arid rather than wetter, as most models currently suggest.

Paul Smith’s College, Paul Smiths, NY 12970


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Occupancy Modeling and Applications for Spruce Grouse (Falcipennis Canadensis)

in the Adirondacks.

Ohol, Kevin*1, Ross, Angelena

2, VanHooreweghe, Kristen

3.

Establishing effective methods of wildlife monitoring is a central concern for many resource agencies.

Management decisions that involve threatened or endangered species require reliable estimates of species

occurrence. Occupancy modeling generates statistical models that are capable of producing accurate

estimates of a species’ percent occupancy, and rates of colonization and extinction within sites. Spruce

grouse (Falcipennis canadensis) populations in the Adirondacks have been declining since monitoring

began in the 1970’s. Today they are listed as Endangered in New York State. I used presence/absence

data for the years 2002 – 2006 to generate 16 occupancy models for spruce grouse in 56 Adirondack sites.

My results show a percent occupancy of 0.6540, and a detection rate of 0.6331. I determined that habitat

quality had the greatest influence on the rates of occupancy, as well as the rate of colonization and

extinction for individual sites. Accounting for detection probabilities as well as site- and survey-specific

covariates allow occupancy modeling to produce unbiased estimates of a species’ occurrence and

distribution. Comparing occupancy and detection values over time allows resource agencies to correlate

changes in occupancy or detection rates with the effects of management, or lack there of. The flexibility

and utility of occupancy modeling make it an appropriate tool in constructively monitoring spruce grouse

in the Adirondacks, or other species in need of monitoring or protection.

1Department of Environmenal Studies and Biology, SUNY Potsdam, Undergraduate

2New York State Department of Environmental Conservation: Bureau of Wildlife

3Department of Environmental Studies, SUNY Potsdam

SUNY Potsdam, Potsdam, New York, 13676


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Visual Harmony: The Relationship Between the Built and Natural Environments

From the User’s Perspective

Nina L. Caruso

M.S. in Historic Preservation Candidate

Thesis Advisor: Jeremy Wells, Ph.D., Assistant Professor of Historic Preservation

Thesis Reader: Harvey H. Kaiser, Ph.D.

Historic Preservation Program, School of Architecture, Art and Historic Preservation, Roger Williams

University, [email protected]

Architects and landscape architects of the nineteenth and twentieth centuries considered the importance of

visual harmony, which is defined as a congruency between the built and natural environments, and

designed their “rustic architecture” to be in harmony with the surrounding landscape. The ways in which

these designers intended their work to be perceived by users of their buildings is well known, but we do

not know what visual harmony actually is from the perspective of the sites’ users or even if it is similar to

the designers’ intents. There is a general lack of knowledge from the users’ perspective, and the field of

cultural landscape preservation is at risk of losing the intangible meaning (what is important, what is

meaningful from the user) in an effort to categorize, simplify, and standardized meanings in preservation

practice.

This thesis used Camp Santanoni, a historic site that epitomizes the designers’ concepts of visual

harmony, as the case study to answer this question through the meanings and perceptions of the users of

this camp. Camp Santanoni was designed by Robert H. Robertson and completed in 1893. These

individuals’ perceptions of historical rustic architecture in natural environments is critical to determining

and describing how users perceive and interpret the visual harmony of this type of design in context with

natural environments. The general purpose of this research study attempts to discover how people actually

perceive and interpret the harmony between historical rustic architectural design and the natural

environment, and therefore if these users agree or disagree with the designer’s intent.

The researcher established a timeline for the history of developments concerning the integration of rustic

architecture with the site to achieve harmony. This was necessary to establish a chart identifying specific

building element concepts that designers of the past have indicated make a building harmonious with the


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natural landscape. For the purposes of this study, material written before the completion of Camp

Santanoni in 1893 was used to identify the building elements concepts (Table 1).

Table 1: Building Element Concepts

Building Element Concept

To make a building harmonious with the site

Citation

1 Site Selection:

A site should be chosen for views, naturally

beauty and grandeur

Downing, 1850

Olmsted, 1875

Wicks, 1889

2 Structure Materials:

A structure shall use native materials; wood,

bark, rocks,

Downing, 1844

Downing, 1850

Wicks, 1889

3 Merging Building and Natural Material: The

building should be outgrowth of, and

harmonize with the site

Olmsted, 1875

Wicks, 1889

4

Views:

The building will be oriented in a way allows

for the maximum amount of views looking

out.

Olmsted, 1875

Wicks, 1889

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Water:

If water is present the building will be built in

such a way, that it can be viewed from a

number of vantage points.

Olmsted, 1875

Wicks, 1889

6 Screening:

Buildings will be positioned behind existing

vegetation

Downing, 1844

The researcher used a qualitative interview methodology to answer the research question, supplemented

by a photo-sort task. The purpose of using a photo-sort was for the informant to be able to visually see the

concepts being discussed, and to express his/her interpretation of a harmonious relationship between the

built and natural environments. For the photo-sort task, a focus group was used to select the top five

photographs for each category, which best represented the building element concepts. The top five

photographs selected by the focus group were used to understand what the user perceives to be a

harmonious relationship between the building and the natural environment. The researcher asked the

informants to sort the photos with the top photo most representing the building element concept, and the

bottom photo least representing the concept. The researcher then recorded the photo-sort orders for each

informant. An open-ended interview was conducted after the photo-sort to allow the informant to express

why he/she chose the top two images to best represent the building element concept identified by the


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researcher. In addition, the researcher asked the informant if he/she agreed or disagreed with the

designer’s intent.

Preliminary results suggest that the user agrees with the designer’s intent for all six categories. Sixteen

informants were interviewed and only two informants disagreed with the designer’s intent for one

category (separate categories) out of six categories. Furthermore, the data table shows the informants

consistently chose the same top two images to most represent the building element concept. They either

had the exact same order or swapped the top two.

This research is expected to raise awareness about the historic use of the term “harmony” and the history

of visual harmony—a design history of which many are unaware and a history important to the influence

and development of structures in our National Parks.

This new body of knowledge has the potential to impact the reasons and justifications for a range of

preservation actions performed by historic preservationists and cultural landscape preservation experts by

taking into account users’ perspectives. Moreover, this research is applicable to the Adirondack Park

region. Informants, acting as a kind of “teachers” contribute to the understanding of the research

problem, but also reveal new meanings to the researcher. Many of the informants expressed the need to

educate people about these design principles and their applicability to new construction in the

Adirondacks. It is hoped that these design principles can contribute to the sustainable development

dialogue in the Adirondack Park.

References for the citations listed in the table:

Downing, A. J. (1844). A Treatise on the Theory and Practice of Landscape Gardening.

New York: Wiley and Putnam.

Olmsted, F. L. (1875). Park. In G. Ripley, & C. A. Dana, The American Cyclopaedia: A

Popular Dictionary of General Knowledge. New York: D. Appleton and

Company.

Downing, A. J. (1850). The Architecture of Country Houses. New York: D. Appleton and

CO.

Wicks, W. S. (1889). Log Cabins: How to Build and Furnish Them. New York: Forest

and Stream Publishing Company.


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POSTER: Resident evaluations of community satisfaction in five Adirondack towns.

Shrope, Christopher1 and Pynchon, David

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Adviser: Erik A. Backlund3

Introduction

The purpose of this study was to examine community satisfaction in the Adirondacks. Community

satisfaction is important because it is related to choice of residence. Research shows that those dissatisfied

with their communities are more likely to move away. Retaining residents and ensuring a high quality of

life is important across the Adirondacks when considering the concerns about out-migration and declining

populations. In this study we examine differences in resident evaluations of community services,

conditions, and overall community satisfaction in five Adirondack towns.

Methods

Data come from a household survey of permanent park residents in Harrietstown, Lake George, Tupper

Lake, Warrensburg, and Webb. Five hundred and forty five responses from 1389 randomly selected

households were received for an adjusted response rate of 40%. Respondents first rated the importance of

16 community attributes on a five point Likert-type scale where 1 = “Very Unimportant” to 5 =“Very

Important.” They again rated each of the attributes on a scale ranging where 1=“Completely Dissatisfied”

to 5=“Completely Satisfied.” Finally, respondents rated their overall community satisfaction on a scale

ranging from 1=“Completely Dissatisfied” to 5=“Completely Satisfied.” Mean rating scores were

calculated and differences across communities were assessed using ANOVA.

Results

Overall, 77% of the respondents were “Satisfied” or “Completely Satisfied” with their community.

Across the five communities there were no difference is the level of overall Satisfaction. The most

important community attribute to residents overall were “Scenic Beauty” (m=4.25), “Clean Air”

(m=4.25), and “Fresh Water/Water Quality” (m=4.25). The least important attributes were “Ability to live

off the land” (m=2.91) and “Senior Citizen’s Programs” (m=3.05). Importance was statistically different

(p<.05) across communities for six of the attributes including “Scenic Beauty,” “Access to Recreation

Opportunities,” “Family and Friendship Ties,” “Quality of Schools,” “Youth Activities,” and “Local

Shopping Opportunities.” Respondents were most satisfied with the attributes “Scenic Beauty” (m=4.39)

and “Clean Air” (m=4.32). They were least satisfied with “Cost of Living” (m=3.11) and “Local

Shopping Opportunities” (m=3.12). Satisfaction with five components was statistically different across


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towns, these included “Access to Recreation Opportunities,” “Fresh Water/Water Quality,” “Medical and

Healthcare Services,” “Youth Activities,” and “Local Shopping Opportunities.” Overall satisfaction was

most strongly associated with satisfaction with “Local Shopping Opportunities” (r = .427) and “Rural

Character of Your Community” (r =.414). Quality of schools had no association with respondents’

overall satisfaction evaluations.

Discussion/Conclusions

Results indicate that park residents are highly satisfied with the natural environment surrounding their

communities but unsatisfied by the costs associated with living in the Park. The relationship between

shopping opportunities and overall satisfaction suggests that the lack of shopping opportunities reduces

peoples’ satisfaction with their communities. These findings suggest that there may be a contradiction

inherent in living in the Adirondacks. Residents are most satisfied with community attributes that drive up

the cost of living, the attribute with which they are least satisfied.

1Class of 13, Environmental Studies/Economics, St. Lawrence University

2Class of 14, Environmental Studies, St. Lawrence University

3Assistant Professor, Environmental Studies, St. Lawrence University

Black capped Chickadee feeding behavior: Interactions of food quality and distance

from protective cover By: Jenna Daub

Mentor: Dr. Jorie Favreau

Paul Smith’s College – Fisheries and Wildlife Sciences: Wildlife Concentration

Abstract

When foraging for food, organisms choose the quality of food that will benefit them the most.

Some foraging areas are close to cover, which serves as protection from predators and offers higher

quality food, but may not always offer those conditions, such as poor food quality. The goal of this study

is to determine the relationship between the distance from cover and the choice of food quality by black

capped chickadees. The objective is to understand if black capped chickadees choose higher quality food

as distance increases. My first hypothesis is that black capped chickadees will choose food sources closer

to the cover area than at further distances from cover availability, regardless to food quality. My second

hypothesis is even if the quality of food is greater at a distance black capped chickadees will stay a shorter


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time at the farther foraging site, and spend a longer period of time a site closer cover site with lower

quality food due to predation risk. My final hypothesis is black capped chickadees will choose higher

quality food as the distance from cover increases. This study will be conducted from January to March of

2012. Black capped chickadees will be observed at birdfeeders, which will be placed at 3, 6, 9, 12, and

15, 18 meters from cover availability. Birdfeeders will be randomly selected on the day of observation to

contain either low or high quality find, along with the distance. This study will give more information on

the food quality and location where black capped chickadee forage when they travel to forage in open

areas in the Adirondacks.

Assessing the impact of North American porcupine (Erethizon dorsatum) foraging on

forest composition and structure in northern New York

Author: Erin Siracusa, Undergraduate Student, St. Lawrence University (Graduated on May, 20 2012)

Advisor: Dr. Erika Barthelmess, Associate Professor of Biology, St. Lawrence University

Abstract:

Herbivores, as major constituents of most ecosystems, have the potential to affect vegetation

development and productivity, causing shifts in abundance and distribution of plant species. Foraging

behavior of the North American porcupine (Erethizon dorsatum) is of considerable interest because

winter feeding strategies, namely bark stripping, may cause sublethal or lethal damage to trees. During the

winter months foraging around den sites is also fairly localized and high in intensity, exacerbating the

potential effects of porcupine herbivory. Few studies have sought to explore the ecological significance of

porcupine foraging and its potential effects on the composition of forest communities. Although browsing

pressure alone has the potential to significantly affect the vertical complexity of forest stands by creating

canopy gaps and introducing structural diversity into otherwise homogenous stands, preferential feeding

may further influence plant community composition. By selectively feeding on certain species, porcupines

may allow for the competitive release of sub-dominant species within the forest community, potentially

enhancing the diversity and species richness of a given stand.


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This study assessed the impact of winter foraging behavior of porcupines on forest composition

and structure. Between October 2011 and February 2012, I established four survey plots; two den plots

and two random plots within Glenmeal State Forest in Canton, New York to assess the effect of winter-

feeding behavior of porcupines on northern hardwood forests. In each plot I identified all trees to species,

measured their diameter at breast height (dbh), and classified each as an adult (dbh > 5.0cm), sapling (dbh

≤ 5.0cm), or snag (standing dead tree). Since the frequency and distribution of scars that develop in

response to porcupine feeding on the bark of woody plants provide an indication of winter food

preferences, I assigned each tree a wound score between 0 and 4 to quantify damage from porcupine

feeding.

Forest composition appeared very different between den and random plots. Den plots had a lower

density of adult trees and a higher density of saplings and snags than random plots. The densities of two

subdominant species, eastern hophornbeam and striped maple, were also much higher at den than random

plots. The top five species with the highest importance value (relative density x relative dominance) for

den sites were eastern hophornbeam, striped maple, red maple, sugar maple, and eastern hemlock, while

the top five species with the highest importance value for random sites were sugar maple, eastern

hemlock, eastern white cedar, yellow birch, and blue beech American hornbeam, providing strong

evidence to show that den communities and random forest communities are quite different in

composition, and suggesting a link between porcupine herbivory and change in forest community

structure. Although observational studies have suggested that porcupines structure communities through

preferential feeding, data from this study suggests that porcupine selection of tree species tends toward

more generalist feeding behavior, facilitating the growth of multiple species and potentially increasing the

diversity of forest communities at den sites over time.

Porcupine foraging exerts considerable influence on the structure of forest communities by

creating patches of small-scale disturbance that facilitate succession and new growth. Much of the

prevailing sentiment around porcupines deigns them a nuisance species whose bark gnawing incurs

considerable commercial costs to both personal property and the lumber industry. However, porcupine

foraging appears to be more beneficial than detrimental to forest communities. No commercially

important species, such as sugar maple, appear to be functionally eliminated by feeding behavior, and the

diversity of forest stands is enhanced through intermediate levels of disturbance. Furthermore, by mortally

wounding trees, porcupines appear to facilitate the creation of snags which are key habitat for numerous

species of birds that use standing dead trees for breeding, roosting and foraging sites. Understanding the


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benefits of such browsing behavior is essential to altering misconstrued views of the porcupine and

perhaps limiting the bounty-hunting and poisoning programs that occur as a result of such

misunderstandings. Further studies will be needed to help confirm these trends and to further our

understanding of the extent to which porcupines serve as agents of disturbance and renewal in the

hardwood forests of northern New York.

Variation in litter decomposition between native speckled alder and non-

native European buckthorn: an experimental study in Plattsburgh, NY

Kali M. Blankenship, Ecology Undergraduate Program/Center for Earth and Environmental Science,

Plattsburgh State, Plattsburgh, NY

Faculty Advisor: Dr. Rachel E. Schultz, Assistant Professor of Environmental Science/Center for Earth

and Environmental Science, Plattsburgh State, Plattsburgh, NY

Background/Question/Methods

The increasing incidence of invasive species, both flora and fauna, has motivated research on the effects

of non-native species on various ecosystem processes including nutrient cycling. Litter decomposition is a

process in which organic matter is broken down and inorganic nutrients become available to plants. While

we know that specific traits of plant species influence decomposition rates, few studies have taken into

account the effects that invasive shrub species have on litter decomposition at a continental scale. The

DATIS (Decomposition of Aquatic and Terrestrial Invasive Species) study is being conducted by EREN

(Ecological Research as Education Network) and provides the same methods and analysis instructions to

multiple undergraduate institutions in order to perform the study across North America. The main

objective of the study was to test the effect of invasive species litter on leaf decomposition rates along an

invasive to native gradient. This will help determine the level at which invasive species would need to be

present to start affecting basic ecosystem processes such as nutrient cycling of nitrogen and carbon. We

studied litter decomposition of the native speckled alder (Alnus incana ssp. rugosa), and the invasive

European buckthorn (Rhamnus cathartica). Five different compositions of litter bags were assembled

with varying percents of alder versus buckthorn totaling at 8g ±.02 g each. We included five replicates for

each treatment for a total of, twenty-five bags. We let the litter bags incubate for ninety-eight days in a


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wooded area next to the Saranac River on the SUNY Plattsburgh campus in Plattsburgh, NY. At the end

of the incubation period, all bags were removed from the field, rinsed and dried at 55 °C for 72 hours. We

then measured the litter dry weight. For the control group, three replicates of each treatment were taken to

the site and then immediately taken back, rinsed and dried at 55 °C. We used the resulting dry weight to

determine mass lost during travel. Using Microsoft Excel, all beginning and final weights were used to

determine the total mass lost in grams for each bag. The percent mass lost was determined by dividing the

total mass lost by initial mass. The decomposition rate (percent mass lost per day) and the decay constant

(k) were calculated from the average mass lost the percent mass remaining for each treatment.

Results

The range of percent mass loss for each of the five treatments was 4.58% to 38.1 % (F=20.8002,

P<0.001). Percent mass lost increased with an increase in the invasive species (buckthorn) litter (Figure

1). The 100% alder bags had a percent mean loss of 4.58 % ± 5.95(95% confidence interval) while the

100% buckthorn bags had a percent mean loss of 38.1% ± 5.98. The 50% alder and 50% buckthorn bags

had a percent mean loss of 19.6% ± 5.94. The 100% alder bag had a decomposition rate of 0.05% per day.

The 50% alder and 50% buckthorn bag had a decomposition rate of 0.20% per day. The 100% buckthorn

bag had a decomposition rate of 0.39% per day.


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Figure 2 Percent mass lost (95% ±confidence interval) after 98 days incubation for litter bags (n=25) containing variations in native alder (N) and invasive buckthorn (I) litter in Rugar Woods, Plattsburgh, NY. Means not sharing the same letter are significantly different (Turkey HSD, P <0.05).

The trend in data indicates that the rate of decomposition of invasive European buckthorn is faster than

the rate of decomposition of the native speckled alder. The level at which decomposition became

significantly different from native litter decomposition was when there was at least 50% invasive litter

present. Several physio-chemical traits could explain the difference in decomposition between the species

including levels of lignin and tannin, which can slow down the rate of decomposition, and the

concentration of nitrogen and carbon which may attribute to a faster rate of decomposition (Cornelissen,

1996). Even though both leaves are present in the same environment, the concentration of nitrogen and

carbon to nitrogen ratios will affect the rate of decomposition by microorganisms, invertebrates and fungi

(Cornelissen, 1996). Most invasive species demonstrate these faster rates due to the fact that they are

more nitrogen rich and have a lower carbon to nitrogen ratio in compared with native species.

-5

0

5

10

15

20

25

30

35

40

45

50

100% N/0% I 75% N/ 25% I 50% N/50% I 25% N/ 75% I 0% N/ 100% I

Mas

s Lo

ss (

%)

Treatment (% of Native (N) and Invasive (I) Litter)

D

DC

CB

BA

A


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Investigations into Midwestern woodlands that are invaded by non-native European buckthorn have

established that it increased levels of nitrogen, carbon and increased pH in the soils (Heneghan et al.,

2006). Due to the higher rates of decomposition, an increase in soil nutrients can change the soil, animal,

and plant community characteristics of an ecosystem. Higher levels of nitrogen, carbon, and a less acidic

soil could negatively affect the native species of woodlands, like the native speckled alder. If conditions

are drastic enough, major losses in the amount of biodiversity in an ecosystem, such as a forest, can have

an overall negative effect on nutrient cycling therefore, further degrading ecosystems.

Literature Cited

Cornelissen, J.H.C. 1996. An experimental comparison of leaf decomposition rates in a wide range of

temperate plant species and types. Journal of Ecology. 84:573-582.

Heneghan, L., Fatemi, F., Umek, L., Grady, K., Fagen, K., Workman, M. 2006. The invasive shrub

European buckthorn (Rhamnus cathartica L.) alters soil properties in Midwestern U.S. woodlands.

Applied Soil Ecology. 32:142-148.

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