Alex Matzinger final

51 Pages·2011·1.45 MB·English

by  Alexandra Matzinger

Bat Activity in Relation to Landscape Composition and Spatial Configuration in Wisconsin

By
Alexandra F. Matzinger

An Undergraduate Thesis
Submitted in Partial Fulfillment for the Requirements of
Bachelor of Arts
in
Geography and Earth Science

Research Mentor: Dr. Deanna Byrnes
Carthage College

Kenosha, WI

April 2011

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Bat Activity in Relation to Landscape Composition and Spatial Configuration in Wisconsin
By
Alexandra F. Matzinger

Abstract
With the devastating effects of White-Nose Syndrome rapidly spreading towards
Wisconsin, identifying the abundance and distribution of bats within the state is becoming
increasingly vital. In order to identify patterns of activity and distribution two major questions
were addressed through the study: the general distance bats tend to travel from hibernacula
locations to summer roosting locations, and the type of land cover that has the highest associated
percentage of bat activity. Three major data sets were analyzed and compared primarily through
the means of geographical information system software. The data consisted of recorded bat
activity from the Wisconsin Department of Natural Resources from the year 2008, four major
hibernacula locations, and 30x30 meter land cover classification data from the National Land
Cover Database from 2001. The data was analyzed spatially and statistically through spatial
joins, multiple ring buffers, and a nonparametric test. The results suggest that there are greater
amounts of bat activity at farther distances from the hibernacula site, and that there are highest
percentages of bat activity in association with open water and developed open space land cover
types. These results form the basis of a general bat census that with additional research can form
the foundation for more effective and efficient bat management and potential recovery plans.

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Table of Contents
Abstract……………………………………………………………………………..ii
List of Figures………………………………………………………………………iv
List of Tables…………………………………………………………………….…v

Introduction………………………………………………………………………...1

Methodology………………………………………………………………………..14
Study Area…………………………………………………………………………..14
Data Acquisition…………………………………………………………………....15
Descriptive Statistics………………………………………………………………..19
Geographical Analysis……………………………………………………………...20
Statistical Analysis………………………………………………………………….21

Results……………………………………………………………………………….22

Distance Analysis…………………………………………………………………...26
Micro-Habitat Analysis……………………………………………………………..31
Macro-Habitat Analysis………………………………………………………….....32
Statistical Analysis…………………………………………………………………..34

Discussion……………………………………………………………………………36
Conclusion…………………………………………………………………………...36
Limitations…………………………………………………………………………...37
Outlook and Future Direction…………………………………………………….....38

Acknowledgments…………………………………………………………………...40

Appendices…………………………………………………………………………...41

References.....................................................................................................................45

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List of Figures
Figure 1 White-Nose Syndrome and Bat Hibernation Areas-Summer 2010 2
Figure 2 Wisconsin Habitat Providences 10
Figure 3 Four Major Hibernacula Locations 15
Figure 4 Recorded Bat Activity Passes per Km throughout WI in 2008 23
Figure 5 2001 Land Cover Classification Distribution in Wisconsin 25
Figure 6 Known Bat Activity per Hibernacula Site 26
Figure 7 Percent of Recorded Bat Activity per Buffer Zone 28
Figure 8 Buffer Zone Overlap 29
Figure 9 Neda Mine and Beetown Mine Buffer Zone Overlap 30
Figure 10 Spearman Rank Correlation Equation 35

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List of Tables
Table 1 Four Major Hibernacula Sites 14
Table 2 National Land Cover Database Classifications 17
Table 3 Percentage of Land Cover within Wisconsin 24
Table 4 Distance Analysis Buffer Zone Data 27
Table 5 Percentage of Bat Activity per Land Cover Type 31
Table 6 Percentage of Land Cover Types per Buffer Zones 33
Table 7 Spearman Rank Correlation Table 34

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Introduction
The distribution and abundance of organisms vary over both time and space. The
understanding of this element of ecology has applied importance. Thus, ecologists often seek to
gain a better understanding of the influencing factors that determine the distribution and
abundance of populations. Knowledge of these factors can be used to implement management
and conservation efforts to help prevent population declines. Many species are experiencing
population decline due to both human influences and natural causes. Urbanization continues to
be an increasingly abundant human caused threat to the natural world by negatively affecting
ecosystems through habitat destruction and pollution. Diseases have also been a large contributor
to the decline of many populations of species. The effects of diseases on animals in an ecological
setting can be highly devastating because it weakens organisms resulting in a lower level of
fitness (Krebs 2001). The measure of fitness relates to the number of offspring an individual
contributes to future generations (Molles 2008). These deterimental effects on ecosystems and
organisms have significant influences on threatened species affecting both their distribution and
abundance. Thus, ecologists and govermental agencies devote time and research towards
conservation efforts and disease epidemiology to help manage declining populations. To do this
effectively it is important to have an understanding of where populations of threatened species
are currently found, unoccupied habitats, and factors influencing this division.
Within the past several years bat ecologists and the Department of Natural Resources
have switched a majority of their attention towards a fatal disease that is rapidly spreading across
the country and decimating the nation’s bat populations. The deadly disease, White-Nose
Syndrome (WNS), is caused by the soil fungus Geomyces destructans, which thrives in cold
conditions and is affecting the cave bat species that hibernate within caves during the winter
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months (Bayless 2010). Fatalities due to WNS were first detected in hibernation caves within the
state of New York at the beginning of 2006 and have been quickly moving westward (Fig 1). In
only four years, there have been more than a million documented dead or dying bats across
fourteen states (Kassulke 2010). Death rates are approaching one hundred percent in some
species. Affected bats display the
fuzzy fungus on their noses, ears,
and/or wing membranes. The disease
causes the bats to come out of
hibernation prematurely and use up
their stored fat reserves disabling them
from being able to make it through the
Figure 1: This map depicts the westward spread of
white-nose syndrome.
Source: Bat Conservation International
winter months without freezing or
starving to death (Kassulke 2010). If the bat population continues to experience high mortality
rates, the United States may possibly face total loss of cave-roosting bat species.
There are two reasons that have led to and enabled the spread of WNS. The means of
spreading within the caves is through direct contact from one bat to another, due to their close
proximity to each other as they cluster within caves and mines during hibernation (Kassulke
2010). The means of spreading from one cave to another is due to human aided dispersal from
the footwear, clothing, and gear of individuals who unknowingly carry it with them from one
cave to another while exploring the caves (Kassulke 2010). The high bat mortality due to the
spreading disease is predicted to have incomparable consequences on the health of the natural
ecosystem and the North American economy. The decline in bats can potentially lead to an offset
within the ecosystem and an increase in insects, many of which are considered agricultural pests.
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The disease has not yet reached the State of Wisconsin but if it continues to progress, as it has
over the past four years, it is expected to affect the bat populations within Wisconsin sometime
in the very near future.
To help prepare for the possible devastating effects of this horrific disease, the Wisconsin
Department of Natural Resources (WI DNR) has been making efforts to determine a crude
census of bat populations and dense areas of bat activity. This will aid in implementing effective
management, conservation efforts, and recovery plans. These are vital in the event that WNS
reaches Wisconsin, which has the possibility of eliminating the state’s cave-roosting bat
populations causing extinction. To determine the distribution and abundance of Wisconsin bat
species, the WI DNR are using trained volunteers to conduct a statewide acoustic monitoring
survey of bat activity through the Wisconsin Citizen-Based Monitoring Network. The volunteers
are provided with and taught how to use ultrasound detectors combined with GPS technology
allowing the bat calls to be recorded and analyzed to determine the amount of activity at specific
GPS points (Kassulke 2010). This will allow activity to be plotted on a map and analyzed. Thus,
the WI DNR can gain a better understanding of the geographical distribution of bats throughout
the State of Wisconsin.
On a large scale bats are found geographically worldwide. Of the approximate 5,500
species of mammals in the world bats comprise 21 percent of that total and are recorded to reside
on every habitable continent (Kurta 2008). They make up the order Chiroptera, which is divided
into two suborders, Megachiroptera (Megabats) and Microchiroptera (Microbats) (Kurta 2008).
Megabats are found in Africa, Asia, and Australia; Microbats are found on those continents as
well as North and South America (Kurta 2008). The suborder Microchiroptera has 17 families
consisting of around 800 species (Feldhamer, et al. 2007). This set of families forage through the
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means of acoustic echolocation, meaning these bats detect prey and obtrusive objects in their
flight pattern by emitting high-frequency, high intensity sound pulses through their nose or
mouth (Feldhamer, et al. 2007). The returning echoes then help to determine size of object, speed
and direction of the object’s movement, the location of the object, and details of its shape (Kurta
2008). The high frequency calls range anywhere from 20 to 100 kilohertz (Kurta 2008). Within
the suborder Megachiroptera, there is only one family, Pteropodidae, which consists of 186
species (Feldhamer, et al. 2007). This family is distinctive from the rest because instead of
echolocating, their food sources of fruit, pollen and nectar are found through olfaction, or sense
of smell (Feldhamer, et al. 2007). Due to their diet bats play an important role of pollination and
seed dispersal in the ecosystem (Feldhamer, et al. 2007). These bats are primarily foliage-
roosting bats that may fly up to 100km to foraging areas and possibly migrate 1,500km annually
(Feldhamer, et al. 2007). The two suborders provide a wide range of diversity to the order.
Bats are not only diverse in their geographical ranges but also in their body size and their
diets. Microbats, which make up 90 percent of the order, range in size from the hog-nosed bat
(Craseonycteris thonglongyai) of Thailand, which is the smallest weighing about 2g to the false
vampire (Vampyrum spectrum) of South America weighing almost 227g (Kurta 2008). Bats
within the suborder Megachiroptera tend to be larger, the largest being the Greater Flying Fox
(Pteropus vampyrus) weighing about 1,497g with a wingspan of around 5ft (Kurta 2008).
However, on average between the two suborders most bats are small weighing anywhere from
10-100g (Feldhamer, et al. 2007). Their feeding habits are also varied. There are large fruit-
feeding bats in the Asian tropics; fish-feeding bats in tropical America; sanguinivore vampire
bats and nectar-feeding bats in Mexico, Central America, and South America. Most bats,
throughout the world, especially in temperate regions or outside tropical regions, feed on insects
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(Jackson 1961). In one nightly feeding bats can consume up to their own body weight in flying
insects including mosquitoes, green stinkbugs, spotted cucumber beetles, moths, and midges
(Kurta 2008). This wide range in food sources is beneficial because it does not geographically
restrain bats.
Of the 17 families within the suborder Microchiroptera only one is represented within the
State of Wisconsin. This family of common bats is known as Vespertilionidae and is the largest
of all 17 families. Their distribution is worldwide with a large amount of diversity in size,
appearance, and feeding habits. The Vespertilionidae family consists of 407 species, eight of
which reside within Wisconsin. All eight bat species residing within the State of Wisconsin are
insectivorous, echolocate to find their prey, and are detectable through the method of acoustic
monitoring. These species are Myotis lucifugus (Little Brown Myotis), Myotis septentrionalis
(Northern Long-eared Bat), Perimyotis subflavus (Eastern pipistrelle), Eptesicus fuscus (Big
Brown Bat), Lasiurus borealis (Eastern Red Bat), Lasiurus cinereus (Hoary Bat), Lasionycteris
noctivagans (Silver-haired Bat), and Myotis sodalis (Indiana Bat) (Feldhamer, et al. 2007). These
eight species provide variation in their defining characteristics, habits, and geographical
distribution within Wisconsin.
These bats can be subdivided into hibernating bats and migratory bats. There are three
migratory bats species, also known as foliage-roosting or tree bats, that survive the cold winters
by migrating south toward warmer climates (Kassulke 2010). The tree bat species found within
Wisconsin are the Lasiurus borealis (Eastern Red Bat), Lasiurus cinereus (Hoary Bat), and
Lasionycteris noctivagans (Silver-haired Bat) (Kassulke 2010). The remaining five bat species
are hibernating bats, also known as cave-roosting or cave bats, which spend the winter months
hibernating in caves or mines. As the flying insect populations decline due to dropping
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