A Thesis

entitled

The Short-term Impacts of Burning and Mowing on Prairie Ant Communities of the Oak

Openings Region

by

Russell L. Friedrich

Submitted to the Graduate Faculty as partial fulfillment of the requirements for the

degree of Master of Science in Biology (Ecology track)

______Dr. Stacy Philpott, Committee Chair

______Dr. Jonathan Bossenbroek, Committee Member

______Dr. Daniel Pavuk, Committee Member

______Dr. Patricia Komuniecki, Dean College of Graduate Studies

The University of Toledo

May 2010

Copyright 2010, Russell L. Friedrich

This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author.

An Abstract of

The Short-term Impacts of Land Management Techniques on Prairie Ant Communities

by

Russell L. Friedrich

Submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of Master of Science in Biology (Ecology track)

The University of Toledo May 2010

Controlled burning and mowing are among the most common forms of disturbance in prairie grasslands. Extensive studies on vegetative responses to fire, grazing, and mowing have been investigated, however, there is a lack of information on how animals and particularly insects are affected by these disturbances. Ants in particular play vital ecological roles in nutrient cycling, soil structure and turnover, predation, and seed dispersal, but few studies have assessed ant response to land management practices in prairie ecosystems. This research will assess the short-term impacts of controlled burning and mowing on ant communities. Ants were sampled in 17 prairie sites, divided into three treatments (burn, control, mow) within the Oak Openings Region in Ohio. All burn and mow sites were managed in November 2008 or April 2009 and sampled five times (once per month) with tuna baits between April 2009 and August 2009. Ant abundance, activity and richness were recorded and compared between months and among treatments. A total of 32 species were recorded, including two state records

(Dorymyrmex insanus and Formica gynocrates). Control and burned plots had the greatest number of species (25 species each) while the mowed plots had 17 species. Ant activity levels and mean number of occurrences on baits did not differ depending on

iii management type or within each management type by month, but did differ between the months of sampling period. Species similarity differed for all three management types, and differed in early and late summer. Thus, land management affects ant communities in terms of species similarity and richness, but not for abundance or activity of ants. This means in the short-term, burning and mowing have little impact on ant communities overall; however, differences in species composition may have important implications for prairie systems.

iv

Dedicated to my parents, Terry and Mary Lou Friedrich, and to my sisters Meryl and

Isabel for always supporting me.

v

Acknowledgements

This thesis would not have been possible without the support and aid (financially and emotionally) of my family and close friends. I would also like to thank Peter Bichier,

David Gonthier, Leigh Moorhead, Cody Murnen, Gabriella Pardee, Lindsey Pierce, and

Jon Richardson for help in the field, Melanie Coulter for information regarding the management history and Kal Ivanov at Cleveland State University for identification help.

I thank my committee members, Dr. Jonathan Bossenbroek and Dr. Daniel Pavuk, for guidance and input on my thesis and especially my advisor Dr. Stacy Philpott who has invested countless hours into me over the past few years and has been the greatest mentor

I could have asked for.

I would also like to acknowledge Gary Haase and Kitty Todd Nature Preserve

(The Nature Conservatory) and Oak Openings Metroparks (especially Karen Menard and

Tim Gallaher). Thanks to The University of Toledo Department of Environmental

Sciences and the Toledo Naturalist Association for funding.

vi

Contents

Abstract…………………………………………………………………………………..iii

Acknowledgments ……………………………………………………………………….vi

Contents …………………………………………………………………………………vii

List of Tables ………………………………………………………………………..…...ix

List of Figures ………………………………………………………………………....…x

1 Chapter 1: The Short-term Impacts of Land Management Techniques on Prairie Ant

Communities in the Oak Openings Region

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

1.2 Objectives ……………………………………………………………………….5

1.3 Materials and Methods …………………………………………………………..6

1.3.1 Study sites ………………………………………………………………..6

1.3.2 Ant sampling ……………………………………………………………..8

1.3.3 Site characteristics………………………………………………………..9

1.3.4 Analysis…………………………………………………………………..9

1.4 Results ………………………………………………………………………….11

1.4.1 Ant sampling results…………………………………………………….11

1.4.2 Site characteristics and environmental correlates of ant communities …15

1.5 Discussion ……………………………………………………………………...16

vii 1.5.1 General characteristics of the Oak Openings ant community…………...16

1.5.2 Effects of prairie management on ant communities ……………………18

1.6 References ……………………………………………………………….……..38

2 Chapter 2: Formica gynocrates (Snelling and Buren) and Dorymyrmex insanus

(Buckley) encountered as new ants for Ohio

2.1 Introduction ……………………………………………………………….……43

2.2 Methods ……………………………………………………….……………..…44

2.3 Recognition………………………………………………………………..……46

2.3.1 Recognition of D. insanus ………………………………………………..46

2.3.2 Recognition of F. gynocrates …………………………………………….47

2.4 Discussion ……………………………………………………………………...47

2.5 References ……………………………………………………………………...51

viii

List of Tables

1-1 Study locations and management description for 17 study sites. ………………...…24

1-2 Land management history of prairie study sites in the Oak Openings region of NW

Ohio. ………………………………………………………………………….….…..25

1-3 List of ant species found in the prairies of the Oak Openings region in Northwest

Ohio. …………………………………………………………………………………26

1-4 Mean (± standard error) for environmental variables measured in managed (burn and

mow) and control prairies in the Oak Openings region of NW Ohio ……………….27

ix

List of Figures

1-1 Species accumulation curves for observed ant richness in praries under three

management regimes per the total number of occurrences of all ant species. Error bars

show 95% confidence intervals.……………… ……………………………….……28

1-2 Rank abundance of all ant species present in prairies with different land management

practices. The number of occurrences for each species shows the number of baits

occupied by each species in each habitat type. Species are organized by total

abundance in control sites ………………………………………………………...…29

1-3 Mean ant abudance across five months in prarie sites with different management. Ant

abundace is measured by colony occurreces on baits by month. ……………………30

1-4 Nonmetric Multidimensional Scaling (NMDS) of ant species similarity for each

sampling month across all management types. April = red crosses, May = green x’s,

June = blue squares, July = grey triangles, August = black dots. Ellipses represent

95% CI for each month, and each color corresponds to the month with the same

color………………………………………………………………………………….31

x 1-5 NMDS plot showing ant species similiarity between the three management types.

Each point represents one plot, and the colors are as follows: burn = red crosses,

control = blue squares, mow = green x’s. Ellipses represent 95% CI for each month,

and each color corresponds to the month with the same color.……...……..………..32

1-6 Canonical Correspondence Analysis biplot comparing ant species composition,

relative abundace of 24 ant species, 8 environmental factors in 17 sites differing in

prairie management during the month of April. The lines represent the environmental

variables, codes represent the sites, and numbers represent the and species.

Corresponding species numbers located in Table 1-3 and site codes in Table 1-1…33

1-7 Canonical Correspondence Analysis biplot comparing ant species composition,

relative abundace of 22 ant species, 8 environmental factors in 17 sites differing in

prairie management during the month of May. The lines represent the environmental

variables, codes represent the sites, and numbers represent the and species.

Corresponding species numbers located in Table 1-3 and site codes in Table 1-1….34

1-8 Canonical Correspondence Analysis biplot comparing ant species composition,

relative abundace of 23 ant species, 8 environmental factors in 17 sites differing in

prairie management during the month of June. The lines represent the environmental

variables, codes represent the sites, and numbers represent the and species.

Corresponding species numbers located in Table 1-3 and site codes in Table 1-1…35

xi 1-9 Canonical Correspondence Analysis biplot comparing ant species composition,

relative abundace of 23 ant species, 7 environmental factors in 17 sites differing in

prairie management during the month of July. The lines represent the environmental

variables, codes represent the sites, and numbers represent the and species.

Corresponding species numbers located in Table 1-3 and site codes in Table 1-1….36

1-10 Canonical Correspondence Analysis biplot comparing ant species composition,

relative abundace of 26 ant species, 7 environmental factors in 17 sites differing in

prairie management during the month of August. The lines represent the

environmental variables, codes represent the sites, and numbers represent the and

species. Corresponding species numbers are located in Table 1-3 and site codes in

Table 1-1……………………………………………………………………………37

2-1 Worker head from a front view (1) and worker mesosoma and head in side view (2),

from Snelling 1995……………………………….…………………………………50

2-2 Worker head from front view (1) and worker mesosoma in side view (2) from

Snelling and Buren 1985……………………………………………………………50

xii

Chapter 1

The Short-term Impacts of Land Management Techniques on

Prairie Ant Communities in the Oak Openings Region.

1.1 Introduction

Prairie ecosystems are characterized by disturbance required to maintain the native vegetation. Prairie disturbance was historically caused by grazers, browsers, naturally occurring fires, and drought (Collins & Wallace 1990). In more recent years, as large grazers have gone extinct in many areas, and as natural fires have been suppressed, management techniques of prescribed burning and mowing are used to simulate these disturbances. Controlled burning and mowing are currently the most common forms of disturbance in prairie grasslands (Pairis et al. 2003) and are implemented to simplify the vegetation structure by discouraging the growth of woody plants, removing accumulated leaf litter, encouraging spread of native prairie grasses and forbs, and reducing exotic plant populations (Howe 1994, Bond & Wilgen 1996). The occurrences of these disturbances are necessary to preserve the prairie grasslands (Swengel 1996); yet the effects of such disturbances are not that well known.

Extensive studies have examined vegetative responses to fire (both natural and

1 prescribed), grazing, and mowing, however, there is a lack of information examining how animals and particularly insects are affected by these disturbances (Whelan 1995,

Zimmer & Parmenter 1998, Parr et al. 2004). In prairie ecosystems, insects are the major pollinators and are imperative to the reproductive success of prairie plants (Detrich et al.

1998, Pairis et al. 2003). Ants in particular have been shown to play vital ecological roles in nutrient cycling (Lal 1988, Hölldobler & Wilson 1990), modification and creation of soil structure, soil turnover (Humphreys 1981), predation, seed dispersal (Beattie 1985,

Beattie & Culver 1981, Beattie 1990, Christian 2001) and are ecosystem engineers

(Folgarait 1998). From what is known, insects vary in their responses to prairie management and there are many concerns as to whether land management has negative effects on insect species, specifically rare and highly localized species (Swengel 1996;

1998, Swengel & Swengel 1997, Cattin et al. 2003). Johst et al. (2006) found mowing influenced two species of endangered butterfly by causing direct mortality to eggs and larvae and to host plants. Another study found grasshopper abundance was reduced in mowed plots compared to unmowed plots presumably due to direct mortality and reduction in grass height (Gardiner & Hassall 2009). Management does not always negatively impact insects; some studies have found the effects of ecosystem management to be insignificant and cause no overall harm to populations (Shuey 1997, Panzer &

Schwartz 2000, Pairis et al. 2003). Other insects benefit from management disturbances.

For example, Huntzinger (2003) reported greater butterfly richness in burned areas and fuel breaks compared to control sites.

This study focused specifically on the impacts of land management (e.g. prescribed burning and mowing) on ants (Hymenoptera: Formicidae) in prairie systems.

2 Despite the overall importance of ants in ecosystem dynamics, few studies have assessed ant response to land management practices. The few studies that do exist have mainly focused on fire as a management tool and often disregard other forms of management

(i.e. mowing and weeding). Further, most studies assessing the impacts of burning on ants have been conducted outside of the temperate climates of North America. Results of controlled fire studies have exhibited mixed responses. In some cases, ant richness and/or abundance increases following burning (Andersen & Yen 1985, Donnelly & Giliomee

1985, Andersen 1991, York 1994, Zimmer & Parmenter 1998). However, other studies observed no change in the ant community (Hoffmann 2003, Parr et al. 2004) or decreases in abundance (Sanders 2004) and species richness (Ratchford et al. 2005) following burning. The negative effects of burning on ant communities are not likely from direct mortality, but rather from destruction of vegetation structure and food supply (New &

Hanula 1998). The inconsistency of findings has been attributed to indirect effects of fire, which may alter habitat and food resources (Anderson 1988, Farji-Brener et al. 2002,

Hoffmann 2003, Parr et al. 2004), differences among habitat types investigated

(Ratchford et al. 2005), moisture gradients (Holway 1998, Sanders 2004), and biogeographical history of the ant species involved (Anderson 2007). Also important to note is the variation in time scale of the sampling period. Some studies investigate on a shorter time scale (generally around one year) to determine the immediate impacts of management practices (Underwood and Christian 2009) while others examine the impacts of management on ant communities on a larger time scale (i.e. multiple years)

(Andersen et al. 2007). Thus, it is difficult to make generalizations about how land management may affect ants in a given prairie ecosystem or ecoregion. Nevertheless,

3 understanding the impacts of land management on ants may be important as they are providers of several ecosystem services and are important components of prairie insect food webs and specific species interactions.

The majority of the Midwestern tall grass prairie ecosystems have been destroyed

(Schwartz & Hermann 1997, Panzer & Schwartz 2000), but in recent years, much effort has been put into restoring and preserving prairie grasslands. In Northwest Ohio in particular, prairie grasslands represent a very small proportion of land cover that is still decreasing due to expansion of farmland and urban areas. Much of the natural prairie landscape that has not yet been developed has gradually changed into woodlands due to lack of management and fire suppression. The areas that maintain historical native grasslands are located mainly in city and state parks that manage the prairies with frequent disturbances. The protected prairie system of the Oak Openings Region in

Northwest Ohio, USA is among one of the most unique ecoregions in the world, and is composed of a very distinct selection of plants and animals, including some rare insects.

The principal management need is the removal of excessive woody vegetation to return the vegetative distribution to historical plant communities (G. Hasse, Pers. Comm.).

Years of fire suppression have altered the plant community to support woody species, but recent land management actions, such as burning and mowing have been in place for several years to 1) promote the survival and reproduction of native and rare plants, and 2) to restore historical prairie sites (Brewer & Venkat 2004). Aside from the fact that few prairies remain in NW Ohio, very little work has been done to document the insect communities, and ants in particular, in the Oak Openings region. Rare for the Oak

Openings, and for Midwestern tall grass prairies, in general, is investigation of how

4 management practices, such as burning and mowing, that are generally designed for maintaining the plant community, may alter the insect community or trophic interactions therein.

1.2 Objectives

The goal of this research was to examine the impacts of two prairie management strategies, burning and mowing, on ant communities in the Oak Openings region by investigating three main objectives:

1) Document the diversity, abundance, and composition of ant species found in the

prairies of the Oak Openings Region,

2) Assess how prairie land management techniques including burning and mowing affect

the prairie ant communities,

3) Document how ant communities respond to this management-induced disturbance on a

short-term scale.

The research is significant for various reasons. Little is known about the ants that occur in the Oak Openings region and this research provides the first extensive list of the ants in the Oak Openings prairies. The impacts of burning and mowing on the native ant species of this region are unknown and the research provides insight as to how these management practices affect ants in Midwestern tall grass prairies. I hypothesized that burning and mowing negatively affect ant abundance, richness and activity due to a significant loss in vegetation cover. Specifically, I predicted an initial decrease in ant species richness at the burned plots, but no changes in the control and mow plots. I also hypothesized the ant species similarity among the burn, mow, and control sites differ

5 throughout the study period.

1.3 Materials and Methods

1.3.1 Study Sites

All research was conducted within the Oak Openings Region in Lucas County,

Ohio in two park systems: 1) Oak Openings Preserve Metroparks (41° 33’N, 083° 51’W) and 2) Kitty Todd Nature Preserve (41° 37' N, 083°47' W). The region is more than 476 km2 (Brewer & Venkat 2004), including 14.57 km2 within the Oak Openings Metropark and 3.44 km2 within Kitty Todd. Elevation in the two preserves ranges from 195 - 210 meters above sea level. Historically the Oak Openings region was about 43% oak savanna, 27% wet prairie, 23% oak woodland, 7% oak barrens, and <1% floodplain forest (Brewer & Venkat 2004). Today, urbanization, agriculture, fire suppression, and increased soil drainage have eradicated or drastically changed most stands of the four major vegetation types (Brewer & Venkat 2004).

Seventeen prairie sites were chosen based on the size of the prairies from maps provided by the land managers, location within the prairies (i.e. distance to roads, wood edges, etc.), and vegetation type as well information provided by land managers relating to their burning and mowing schedules (Table 1-1). Of the 17 sites chosen, 6 were burned, 5 were mowed, and 6 were unmanaged controls. Each site was located a minimum of 400 m from other sites to ensure independence of the ant colonies at each site. Nine of the sites were located at the Oak Openings Preserve Metropark and 8 at

Kitty Todd Nature Preserve.

6 The long term management history varies for each site, but sites were chosen to minimize this variation (Table 1-2). Preserve managers provided burn and mowing history for the prairies. The management history for all the prairies differed in frequency and type of management and each prairie had an individual history, which depends on the logistics of each site, the availability of personnel, and presence of endangered species. In general, during years that the burn sites were not burned, they were often mowed in problem areas (locations with high densities of woody vegetation) to reduce the ground cover of woody vegetation. The control sites differ in time since last managed; however, the areas selected as plots for this experiment have not been managed in at least two years. Three control sites (Dead Hog Dune, Heinemann, and Control 3) have never been burned, but have been mowed and the other three control sites have been burned in 2004 and spring of 2006 respectively. Control sites that were mowed in the past were mowed in problem areas to eradicate undesired vegetation. The records do not indicate the exact location of those mowed areas, but do indicate when the entire prairie was mowed. One control site in particular, South Peils, has been managed frequently due to a population of federally endangered butterfly who’s only host plant requires frequent disturbance to maintain its populations. So for this prairie the current management plan calls for mowing and burning one third each of the prairie site, and leaving the last third unmanaged. The area selected for this study was in the unmanaged area and the last management in the area was a mow in 2007 (G. Hasse, Pers. Comm.). Thus overall, it had been at least 2 years since any control sites had experienced management activity over the entire prairie. Although the sites do have variable land use and management history, this proposed research is designed to determine the short-term effect of land

7 management on the ant communities, not the long-term impacts of these strategies. The burned sites were burned only once a year and the mowed areas were also only managed once during the sampling period.

The burned sites were burned in either fall 2008 or early spring 2009. Although differences in burning dates are not ideal, logistical details prevented many selected sites from being burned during the fall. Controlled burns require ideal wind, soil, and vegetation moisture conditions to be met, and trained certified workers must be present.

Because of differences in burn dates, an initial data analysis were designed to examine differences in sites burned in fall vs. spring. No differences were found, so all burned sites were placed together in analyses and are referred to collectively as burned sites.

Finally, all proper permits were granted from land managers at both parks to conduct this research on their land.

1.3.2 Ant Sampling

To sample the ant community in each site, a baiting method was conducted using tuna fish. At each site, a 14 x 14 m plot consisting of 49 bait locations was established with each bait equally spaced 2 m apart. This method is commonly used for sampling ground-nesting ants (e.g. Perfecto & Vandermeer 2002). The baits were left out for 45 min. Then baits were checked for ants where each ant species present on a bait was recorded for activity (0 = no ants, 1 = 1-3 ants, 2 = 3-10 ants, 3 = >10 ants) then collected and placed in 70% ethanol alcohol for preservation. The specimens were then taken back to the lab and identified to species. Ants were sampled at each site with tuna baits five times over the course of the summer. The first sampling took place in April 2009 once

8 the ants were becoming active. For the sites that were managed in the spring of 2009, sampling occurred no more than 10 days after the management took place. The sites were sampled every month until August 2009. Pre-management sampling was not conducted in early spring due to limited ant activity and uncertainty by the land managers as to which prairies would be burned.

1.3.3 Site Characteristics

Burning and mowing have significant effects on plant communities and changes in vegetation structure and complexity can impact ant communities and trophic interactions involving ants (Bestelmeyer & Wiens 2001). Vegetation data were collected on the same dates sites were sampled for ants to examine for factors potentially correlating with changes in ant richness, composition, or abundance. Two 1 x 1 m quadrats were randomly placed within the 14 x 14 m ant baiting plot. In each quadrat, the vegetation parameters recorded were the percent of the area covered by grass, forbs, bare ground, leaf litter, and woody vegetation as well as the height of tallest vegetation. Soil and surface temperature readings were also taken at the center of each plot each month to investigate possible correlations between ant activity and temperature differences in the plots.

1.3.4 Analysis

To examine changes in species richness due to burning and mowing, two methods were used. First, species accumulation curves were created for observed species richness with EstimateS (Colwell 2005). Sample-based curves scaled to the number of colonies

9 encountered were created to examine differences in species richness in sites differing in management (Gotelli & Colwell 2001). Significant differences in richness among different treatments were assessed by comparing 95% confidence intervals (CIs) also generated by EstimateS. If 95% CIs for accumulation curves for different treatments do not overlap, this indicates significant differences between management types. Second, the species richness in the three management types were compared by calculating mean richness during each sample date and comparing with repeated measures ANOVA. The number of species observed in each site was the dependent variable, and management type was the independent variable, with month as the repeated measure.

Second, the effects of burning and mowing on ant abundance and activity were examined. Because ants are social organisms, encounters of individual ants are not usually considered independent (Longino et al. 2002). Instead, ant abundance is assessed by examining occurrences, or presence at baits. Each occupied bait is considered a separate occurrence that represents an individual ant colony. Ant activity was recorded by taking the sum of the index for each bait.

To examine differences in the species composition of ants, several methods were used. First, rank abundance curves were created to visually compare the relative abundance of different species in different habitats. Second, a non-metric multi- dimensional scaling analysis (NMDS) was conducted to visually examine for differences in degree of species similarity among management types and months. Two statistical analyses were used to examine distribution of points. The NMDS was followed by a nonparametric MANOVA to statistically compare the scatter of the points. Analysis of similarity (ANOSIM) was conducted to statistically examine for differences in species

10 composition overall and in pairs of habitat types and sample months. The NMDS,

NPMANOVA, and ANOSIM were all conducted with Bray-Curtis as the similarity values and were completed with PAST (Hämmer et al. 2001).

Data on site characteristics (e.g. soil and ground temperature, percent cover of vegetation components, height of tallest vegetation) were compared using repeated measures ANOVAs. Where conditions of sphericity were violated (Mauchley’s W close to 0), the Greenhouse-Geiser measure was used to determine significance. Then, correlations between temperature variables and ant abundance and richness were examined to see if these variables were driving observed differences with prairie management. To examine for relationships between ant species and environmental variables at each site a canonical correspondence analysis was conducted with PAST (ter

Braak 1986). The environmental variables for each site during each month were plotted and compared on biplots to determine if any relationships were present between any environmental factors and ant species abundance.

Statistical analyses were conducted using SPSS v. 16.0, PAST, and EstimateS. All vegetation variables were transformed (log +1) to meet conditions of normality.

1.4 Results

1.4.1 Ant Sampling Results

A total of 32 ant species from 16 genera were recorded in the prairies of the Oak

Openings region (Table 1-2). For the cumulative number of species collected across the sampling period of five months, the control and burned plots had significantly higher

11 species richness (25 species each) than the mowed plots (17 species) (Fig. 1-1). However, mean species richness per site did not differ between management types over the course of the summer with burn plots having on average 7.03 ± 0.53 (SE) species, mowed plots with 8.50 ± 0.28 species, and control plots with 6.28 ± 0.54 species (Repeated Measures

ANOVA, F = 2.144, df = 2, 14, P = 0.154). There were also no significant differences in mean ant richness over time (F = 2.017, df = 4, 56, P = 0.104) and no significant management by month interaction (F = 0.585, df = 8, 56, P = 0.786). The genus with the most species was Formica with 11 of the 32 total species (34.4%). Interestingly, two new

Ohio state records were found (Dorymyrmex insanus Buckley and Formica gynocrates

Snelling & Buren). D. insanus was found in both mow and burn plots while F. gynocrates was found only in one control site.

Overall, there were 4,116 total ant occupied baits in all three management types combined. Five ant species represented more than 61% of the total baits occupied. The most common species, Aphaenogaster treatae Forel, was collected on 791 of 4,116 total baits occupied with ants (19.2%). The next most common species were Myrmica sp. 1

(key for Myrmica genus currently unpublished) occupying 480 baits (11.7%), Lasius neoniger Emery (451 or 11.0% of all baits), Paratrechina parvula Mayr (414 or 10.1%), and Formica dolosa Trager (401 or 9.7%). Many rare species were also collected. Eleven of the 32 species collectively represented less than 1% of the total species occurrences

(Fig. 1-2).

The two measures of ant abundance, number of occurrences and ant activity level, did not vary with prairie management. The average number of ant occurrences per plot across the entire sample period in the burn plots was 41.47 ± 5.86 (SE), the mow plots

12 had 47.96 ± 7.89, and the control plots had 55.77 ± 8.50 occurrences per plot. There were no significant differences in occurrences with management (Repeated Measures

ANOVA, F =1.353, df = 2, 14, P = 0.29; Fig. 1-3) or a management by month interaction

(F =0.765, df = 8, 56, P = 0.635). However, occurrences did differ by month with a gradual increase in abundance across the summer (F =7.514, df = 4, 56, P < 0.001). The mean values for the sum of ant activity per plot across the entire sampling period in burn plots was 85.03 ± 12.76 (SE), the mow plots had 96.84 ± 16.8, and the control plots had

105.86 ± 17.26. There were no significant differences in ant activity between the three management types (Repeated Measures ANOVA, F = 0.633, df = 2, 14, P = 0.546) and no management by month interaction (F = 0.78, df = 8, 56, P = 0.622). However, ant activity increased over the course of the sampling period (F = 6.782, df = 4, 56, P <

0.001).

According to both visual and statistical measures, ant composition differed with prairie management. The relative abundance of ant species differed greatly with management type (Fig. 1-2). Several ant species (A. treatae, L. neoniger, Tapinoma sessile Say, Temnothorax ambiguus Emery, Lasius umbratus Nylander, Brachymyrmex depilis Emery, Ponera pennsylvanica Buckley, Temnothorax curvispinosus Mayr) were more abundant in the burn plots, some (Myrmica sp. 1, P. parvula, Monomorium minimum Buckley, Formica incerta Buren, Solenopsis molesta Say, Dorymyrmex grandulus Forel, Dorymyrmex insanus Buckley, Temnothorax texanus Wheeler, Pheidole bicarinata Mayr) were more abundant in the mow plots, and several were most common in the control sites (F. dolosa, Crematogaster lineolata Say, Tetramorium caespitum

Linnaeus, Formica exsectiodes Forel, Aphaenogaster rudis Enzmann, Formica

13 pallidfulva Latreille, Formica lasioides Emery, Formica vinculans Wheeler, Myrmica sp.

2, Formica querquetulana Kennedy & Dennis, Formica subsericea Say, Prenolepis imparis imparis Say, Formica pergandei Emery, Formica gynocrates Snelling & Buren,

Formica integra Nylander) (Fig. 1-2). Three species of rarely encountered ants (B. depilis, L. umbratus, P. pennsylvanica) were found exclusively in burned plots during the first two months after plots were burned. The NMDS results show that species similarity differed during some of the sample months (Fig. 1-4) and in prairies with different management (Fig. 1-5). The analysis of similarity (ANOSIM) comparing ant species composition also differed by month (P = 0.004). Specifically, species composition in

April differed from that in June (P = 0.018), July (P = 0.043) and August (P < 0.001) and also differed between May and August (P = 0.001). There were also significant differences in ant species composition with management type (P < 0.001). The ant composition in burned sites significantly differed from control (P = 0.022) and from mow plots (P = 0.009). The control and mow sites also significantly differed (P = 0.005) (Fig.

1-5). Further analysis was conducted to examine for differences in composition in different management types in individual months, however no significant differences were found. The nonparametric MANOVA, which compares the scatter of points during different months showed differences between months (F = 1.649, P = 0.005). In April, ant communities more greatly differed between sites than in June (P = 0.0262), July (P =

0.0378), and August (P < 0.001) when points were more closely clustered together.

Similarly, ant composition among sites was more different in May than in August where composition in different sites was more similar (P = 0.002). There are also significant differences between the management types (NPMANOVA, F = 3.013, P < 0.001) with

14 the burned sites being the most spread out and the mowed sites being most strongly clustered. Outliers were removed from the analysis and the qualitative and quantative results were similar.

1.4.2 Site characteristics and environmental correlates of ant communities

Most ground cover characteristics did not differ with prairie management type

(Repeated measures ANOVA, F = 0.073, df = 2,15, P = 0.93), across the sample period

(F = 1.442, df = 1.378, 20.68, P = 0.253), and no management by month interaction (F =

0.198, df = 2.757,20.68, P = 0.883). The mean values across all months for percent grass

(F = 5.299, df = 2, P = 0.022), litter (F = 13.769, df = 2, P = 0.001) and bare ground (F =

5.523, df = 2, P = 0.020) cover significantly differed between the three management types (Table 1-4). Control sites had between 1.4 and nearly four times more grass cover than burn sites (P = 0.018). Mow sites had between 1.5-7 times more litter cover than control plots (P = 0.003) and between 4-20 times more litter than burned plots (P =

0.001). Finally, burned plots had up to four times more bare ground than control plots (P

= 0.024). No other significant differences were found for other vegetation characteristics

(percent grass, forbs, litter, woody, bare ground, or height of the tallest vegetation).

There were no differences in mean soil temperatures in the burn, mow, and control plots across all sample dates (Repeated Measures ANOVA, F = 1.291, df = 2, 14,

P = 0.306), and no management by month interaction (F = 0.771, df = 8,56, P = 0.629), but temperature differed by sample month (F = 34.235, df = 4,56, P < 0.001). Soil temperatures were lower in April than all following months and May temperatures were significantly lower than June and August. Similarly, surface temperatures did not differ

15 with management type (Repeated Measures ANOVA, F = 2.831, df = 2, 14, P = 0.093), or between months and management type (F = 1.812, df = 8, 56, P = 0.094). There was an increase in soil temperature across the sample period (F = 9.376, df = 4, 56, P <

0.001). Surface temperatures were lower in April than in June (P = 0.013).

The relationship between ant abundance in the different management types, relative abundance of different ant species, and site characteristics was analyzed using a canonical correspondence analysis (CCA). The results are plotted in the biplots in Fig. 1-

6 to 1-10 for each sampling month. In April (Fig. 1-6), a few species (F. lasioides, L. umbratus, L. neoniger, P. parvula) reacted similarly to differences in forb cover and to the conditions in one burned site (Ostrich prairie). In May, bare ground corresponded to forb and woody vegetation cover and to soil temperature. Several sites (Dead Hog Dune; control, Whalen/Vasvery; burn, Sweet Fern; mow) and one ant species (Myrmica sp. 1) corresponded to changes in litter cover. In June, bare ground and soil temperature were closely linked. Several sites (North Peils; mow, West Office; mow: South Peils; control,

Oak control 2; control: Badger barrens; burn) and species (F. pergandei, D. grandulus, T. texanus) also closely corresponded to one another. Similarly, in both July and August, percent bare ground and soil temperature and surface temperatures were closely related, however, there was no strong correspondence between any species or sites.

1.5 Discussion

1.5.1 General characteristics of the Oak Openings ant community

Over a period of five months, 32 ant species were recorded in the prairies of the

16 Oak Openings region, from a total of 17 upland prairie sites. Whereas certain species were more abundant, Formica included the highest number of species of any genera

(34% of total species). Formica, in general, prefer prairie habitat and represent the most diverse genus of ants in Ohio and northeast North America (Coovert 2005). There were several species that could be characterized as the numerical dominants of these prairies including Aphaenogaster treatae, Myrmica sp. 1, Lasius neoniger, Paratrechina parvula,

Formica dolosa. All of these species share fairly similar behaviors and nesting and habitat preferences. All of these species have moderately large to large colony sizes, are ground foragers and ground nesters, are normally found in open fields/prairie habitat, and are generalist feeders (Wesson & Wesson 1940, Talbot 1954, Traniello 1983, Wheeler et al. 1994, Coovert 2005). Aphaneogaster treatae was particularly dominant, represented in nearly one fifth of all occupied baits. Individuals of this species generally forage in morning and early afternoon (Talbot 1966), overlapping with the time that baiting occurred, thus potentially favoring A. treatae abundance in the samples. These are moderately large ants (5.2-7.6 mm) that nest in fairly large colonies (~700 individuals)

(Coovert 2005) and respond quickly to added food resources. Lasius neoniger is well adapted to many environments and was the only species collected at every site. This species thrives in open habitats such as lawns and prairies and is likely the most common species in Ohio (Coovert 2005). P. parvula, is also a common prairie ant, and prefers open habitats often near woods (Wesson & Wesson 1940). This small ant (1.9-2.5 mm) was frequently found co-occurring on baits with A. treatae (in 270 of 414 or 65% of all of its occurrences). At the site level, there was only one site with P. parvula where A. treatae did not occur, and there, P. parvula only occupied nine baits throughout the

17 summer. The reason behind this common co-occurrence is unknown, but should be investigated further.

In terms of ant richness, Oak Openings grasslands differ from grasslands in other regions. One study in North American desert grasslands (New Mexico and Arizona) found 66 species with four species (D. insanus, M. minimum, S. molesta, T. sessile) in common with the Oak Openings species (Whitford et al. 1999). Another study investigating the impacts of four grassland management types on ant species richness and abundance in Germany found 13 species (Dahms et al. 2005). Underwood and Christian

(2009) collected a total of 16 species of ants in the grasslands of northern California, five of which (B. depilis, D. insanus, P. imparis, S. molesta, T. sessile) were collected in the

Oak Openings Region.

1.5.2 Effects of prairie management on ant communities

Cumulative species richness was higher in the burn and control plots than in the mowed plots. This may be the first piece of evidence that prairie management in the

Midwestern tall-grass prairies may have a short-term impact on ant communities.

Specifically, mowing may temporarily reduce ant species richness. Despite differences in cumulative richness, mean species richness during the five sample months did not differ between the three management types, or for different months. This indicates that the beta- diversity may be greater in the burn and control plots, as the cumulative number of species was greater in those plots. Results from the NPMANOVA also report the same pattern with the control and burn sites being more spread out than the mow plots, indicating greater beta-diversity for the control and burn sites.

18 Other studies investigating the impacts of management on ant communities have yielded varying results. As in this study, Parr et al. (2004) found no differences in mean ant species richness or abundance between burned and unburned sites in South African grasslands, but did record differences in ant assemblage composition. Further, Dahms et al. (2005) found no effects of a range of mowing management types in mean or total ant richness in grasslands. Contrary to the study presented here, others have found increases in ant abundance after fires and declines in abundance in the absence of fire (Andersen

1991, Andersen et al. 2005) or decreases in ant abundance following fire (Andersen &

Yen 1985). Santos et al. (2008) did a study looking at the long-term effects of burning on ant communities in the Amazon forest 15 years after being burned and found data supporting greater species richness in burned areas. A five-year study by Andersen et al.

(2007) examining fire resilient ants in Australia found fluctuation in abundances of ants.

However, there were no differences in total ant abundance with the management changes in the Oak Openings. The only observed changes in ant abundance (measured as occurrences and ant activity) were gradual increases across the sampling period. The variation in ant activity and abundance is consistent across the management types, with increases over time, which may imply management does not have an impact on ant foraging activity directly after management or over a short time scale of five months and increases in both occupied baits and ant activity levels are due to other factors.

The results of the ANOSIM comparing species composition in different months and in different management systems established that: 1) species composition differs based on management, 2), species composition changes with time and 3) within a given management type, species composition did not change over the summer. Thus burning

19 and mowing affected the species composition of prairie ant communities in the Oak

Openings. Other studies have found varying results in ant assemblage structure. Parr et al.

(2004) found significant differences in composition in burned and unburned management units and another study provided little evidence that management affected ant community composition (Hoffmann 2003). Ant assemblages have been documented to be very resistant and resilient to fire management (Hoffmann 2003), but the degree of response can vary due to factors such as annual rainfall, altering the vegetation structure by fire, and the history of ant species response to fire (Parr et al. 2004). Fires that burn with low fuel loads generally have less of an effect on the vegetation structure and thus a lesser impact on the ant communities (Farji-Brener 2002, Hoffmann 2003). The burned sites for this study had little fuel in terms of leaf litter since it was all conducted in prairie systems that have a frequent history of burns and little leaf litter accumulation and maybe a reason no differences were found in abundances and activity between treatments. The changes in species composition over a short timescale (five months) in different management and months appear more related to natural history of the ant species. For example, some ant species like D. insanus, prefer warmer temperatures (Wheeler & Wheeler 1986, Coovert

2005) and were recorded only on the warmest days. Likewise, species that favor cooler temperatures, such as Prenolepis imparis were only encountered early in the year when the soil and surface temperature was colder. Seasonal changes in ant composition have been observed in ants in precious studies using baits in prairies and other systems (Talbot

1943). Similar to what this study found, Andersen (1991) found the thermophilic ant species increase in abundance after frequent fire management due to loss of vegetation cover. Another explanation for finding differences in species composition could be

20 explained by Andersen et al. (2007) where they found ant responses to management only occurred after the second burn of the season concluding long term vegetation simplification by repeated disturbance triggers changes in ant communities. The management history of the Oak Opening prairies may be an important factor that is shaping differences in ant species composition between the three management types since repeated disturbance of the prairies has occurred over the past two decades.

Although some changes in composition were likely related to environmental preferences of certain ant species, the results of the CCA did not show clear correspondences between environmental variables and ant species. There are some patterns between the sites based on the given treatment, especially in the first two months of sampling. In April percent bare ground and surface/soil temperatures were linked with the managed sites – an expected result because with vegetation removal comes higher ground temperatures and lower moisture retention of the soil. There was also a link between some control plots and the percent grass and height of maximum vegetation in

April and May. By June, there were no distinct relationships between sites and environmental factors. Because the vegetation responded quickly to the burning and mowing disturbances it seems unlikely that management of the prairies would shape ant communities structure in a short-term timescale.

Beyond the major results of the study documenting changes in species richness and species composition with prairie management, there are several interesting results that deserve note. For example, three ant species (Brachymyrmex depilis, Lasius umbratus, and Ponera pennsylvanica) were only encountered in the first two months of sampling and only in the burned plots. All of these species are described as being almost

21 exclusively subterranean and are rarely seen foraging on the surface (Coovert 2005). The

L. umbratus feeds mainly on Sternorrhyncha (root aphids and coccids) and P. pennsylvanica feeds primarily on small insects (Bechinski & Pedigo 1981). If burning affects ant food resources (such as root aphids) than subterranean ants that feed on these recourses may be forced to forage on the surface. However, one study found no difference in Sternorrhyncha abundance in burned and control plots and significantly higher Sternorrhynca populations in mowed plots compared to burn and control plots

(Seastedt & Reddy 1991). Thus it seems unlikely that burning affects L. umbratus by limiting root aphid populations. In contrast, microarthropod abundance within the upper 5 cm of soil decreases in burned prairies (Seastedt 1984). Thus P. pensylvanica, a predator that depend on soil microarthropods for food could be forced to forage on the surface to locate needed food resources. The observed increase in subterranean species after burning conflicts with previous research finding decreases in abundance of cryptic species after disturbance (Andersen & Yen 1985, Andersen 1991). However, one study did find an increase in abundance in a cryptic ant species (B. depilis) after a prescribed burn

(Underwood & Christian 2009). Further, the occurrence of cryptic ants post-burn may be due to the facts that a) cryptic species are able to survive fire because of their subterranean habitats, b) are able to respond positively to the shock of the disturbance because of their tolerance of dry soils and finally, and c) they are capable of recolonizing burned regions quickly due their social nature (Warren et al. 1987).

Overall, prairie management in the Oak Openings region with prescribed burns and mowing has few important effects on ant communities in the short-term. The compositional analyses suggest that it is unlikely land management has significant effects

22 in the short-term timeframe after prairie disturbance, however, because differences were found in species similarity of different management types, and because the species richness was greater in control and burned plots, there may be long-term effects of land management on prairie ant communities. Thus, the management history of the sites may be an important factor in shaping the ant communities and unfortunately was impossible to control for.

In conclusion, the Oak Openings Region supports a diverse composition of prairie ant species. There are five species of ants that were extremely common in the prairies and three rarer cryptic species that became more abundant after burning management occurred. Burning and mowing do not impact mean species richness, ant activity, or mean ant abundance in a short-term time period in the prairie systems. Ant species similarity was different between treatments and between months, but not between months within each treatment. There are also no obvious patterns linking environmental factors to specific ant species or the sites they occur in. Thus, the short-term impacts of burning and mowing on prairie ant communities at the surface may be minimal and overall do not have negative effects for ant communities. However, the specific changes in species composition due to burning may have important implications for ant-provided ecosystem functions within prairie ecosystems and should be further investigated.

23 Table 1-1 Study locations and management description for 17 study sites in the Oak Openings of NW Ohio.

Site Name Site Code Management Latitude Longitude Type Mancy B3 Burn 41° 37’ 03.3” N 83° 48’ 41.1 ” W Badger Barrens B1 Burn 41° 32’ 34.7” N 83° 53’ 33.5” W South Parkway B5 Burn 41° 32’ 52.6” N 83° 51’ 08.9” W Ostrich B4 Burn 41° 32’ 07.0” N 83° 50’ 22.8” W Girdham South B2 Burn 41° 33’ 01.5” N 83° 51’ 09.9” W Whalen/Vasvery B6 Burn 41° 32’ 06.6” N 83° 51’ 09.9” W North Peils M3 Mow 41° 37’ 15.0” N 83° 47’ 14.9” W West Office Prairie M5 Mow 41° 37’ 07.4” N 83° 47’ 32.1” W Moseley Barren 2 M1 Mow 41° 36’ 29.4” N 83° 48’ 40.9” W Moseley Barren 3 M2 Mow 41° 36’ 18.4” N 83° 48’ 47.3” W Sweet Fern M4 Mow 41° 36’ 27.9” N 83° 48’ 06.6” W South Peils C6 Control 41° 37’ 03.9” N 83° 47’ 06.0” W Heinemann C2 Control 41° 34’ 40.3” N 83° 51’ 16.4” W Dead Hog Dune C1 Control 41° 37’ 32.0” N 83° 46’ 48.9” W Oak Control 1 C3 Control 41° 33’ 14.5” N 83° 51’ 18.4” W Oak Control 2 C4 Control 41° 33’ 00.4” N 83° 51’ 20.7” W Oak Control 3 C5 Control 41° 34’ 25.5” N 83° 51’ 17.3” W

24 Table 1-2 Land management history of prairie study sites in the Oak Openings region of NW Ohio.

Site Name Management Dates Burned Dates Mowed Date/type of Last Type Management Mancy Burn 1998 2007 Nov. 2008 (burned) Badger Barrens Burn 2005 2005, 2006, 2007* April 2009 (burned) South Parkway Burn 1995, 1998, 2001, 2003 2006*, 2007* April 2009 (burned) Ostrich Burn 2005 2003, 2006, 2007* Nov. 2008 (burned) Girdham South Burn 1990, 1996, 1998, 2000, 2002*, 2005*, 2006, 2007* April 2009 (burned) 2001 Whalen/Vasvery Burn 2003, 2005 2004, 2007 Nov. 2008 (burned) North Peils Mow 1994, 1998 (wildfire), 1999, 1998, 1999, 2000, 2002, 2004, 2006, April 2009 (mowed) 2001, 2004 2007 West Office Prairie Mow 2004, 2008 2006, 2007 April 2009 (mowed) Moseley Barren 2 Mow 2000 (wildfire), 2005 2004, 2005, 2006, 2007 April 2009 (mowed) Moseley Barren 3 Mow Spring 2008 2004, 2005, 2006, 2007 April 2009 (mowed) Sweet Fern Mow 2000, 2004 2000, 2002, 2004, 2006, April 2009 (mowed) South Peils ** Control 1987,1993, 1997, 1998 1996, 1997, 1998, 1999, 2000, 2001, 2007 (wildfire), 1999, 2001, 2004 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Heinemann Control Never 2008* 2008* Dead Hog Dune Control Never 2007 2007 Oak Control 1 Control 2003, 2006 2003, 2004, 2005*, 2006, 2007 2007 Oak Control 2 Control 2003, 2006 2003, 2004, 2005*, 2006, 2007 2007 Oak Control 3 Control Never 2005, 2007 2007 * Managed only in problem areas ** Only one third of prairie managed and the area selected for this study was in the unmanaged area

25 Table 1-3 List of ant species found in the prairies of the Oak Openings region in Northwest Ohio.

Subfamily Species CCA Number‡ Dolichoderinae Dorymyrmex grandulus 5 Dorymyrmex insanus* 6 Tapinoma sessile 28 Formicinae Brachymyrmex depilis 3 Formica dolosa 7 Formica exsectoides 8 Formica gynocrates* 9 Formica incerta 10 Formica integra 11 Formica lasioides 12 Formica pallidefulva 13 Formica pergandei 14 Formica querquetulana 15 Formica subsericea 16 Formica vinculans 17 Lasius neoniger 18 Lasius umbratus 19 Paratrechina parvula 23 Prenolepis imparis imparis 26 Myrmicinae Aphaenogaster rudis 1 Aphaenogaster treatae 2 Crematogaster lineolata 4 Monomorium minimum 20 Myrmica sp. 1 21 Myrmica sp. 2 22 Pheidole bicarinata 24 Solenopsis molesta 27 Temnothorax ambiguus 29 Temnothorax curvispinosus 30 Temnothorax texanus 31 Tetramorium caespitum 32 Ponerinae Ponera pennsylvanica 25 *Denotes new state record. ‡CCA number corresponds to numbers on Fig. 1-6 and 1-10.

26 Table 1-4 Mean (± standard error) for environmental variables measured in managed (burn and mow) and control prairies in the Oak Openings region of NW Ohio.

Mngt. Month % Grass‡ % Forbs % Litter %Woody % Bare Height of tallest Soil Surface vegetation (cm) Temp. (C°) Temp. (C°) Burn April 19.2 ± 5.2 8.0 ± 6.0 3.8 ± 2.9 5.0 ± 2.5 64.3 ± 12.9 33.4 ± 6.6 15.6 ± 1.5 24.8 ± 1.4 Control April 71.2 ± 7.9 11.7 ± 4.1 1.8 ± 0.8 0.0 ± 0.0 15.4 ± 6.0 91.0 ± 18.4 14.0 ± 1.0 23.3 ± 1.0 Mow April 60.0 ± 12.0 7.5 ± 2.5 14.0 ± 5.2 0.0 ± 0.0 18.5 ± 11.5 30.2 ± 4.5 15.8 ± 1.7 26.1 ± 1.2 Burn May 41.3 ± 5.4 26.7 ± 6.6 0.8 ± 0.8 1.7 ± 1.1 29.6 ± 5.2 42.8 ± 5.4 19.2 ± 0.8 24.1 ± 0.7 Control May 78.8 ± 4.9 12.5 ± 4.2 2.5 ± 1.3 0.0 ± 0.0 6.3 ± 1.9 93.8 ± 22.4 18.0 ± 2.0 28.4 ± 1.7 Mow May 51.0 ± 10.9 15.5 ± 2.8 3.5 ± 2.4 1.5 ± 1.0 28.5 ± 12.1 34.7 ± 5.0 19.0 ± 1.1 29.8 ± 1.9 Burn June 49.2 ± 6.5 34.2 ±7.1 3.3 ± 1.8 0.0 ± 0.0 13.3 ± 5.1 71.7 ± 11.3 23.8 ± 1.0 30.8 ± 1.9 Control June 73.3 ± 4.0 15.8 ± 3.8 2.1 ± 1.8 0.8 ± 0.9 7.9 ± 2.6 95.2 ± 15.6 21.2 ± 1.3 31.0 ± 1.6 Mow June 50.5 ± 7.1 19.0 ± 1.9 9.5 ± 2.9 0.0 ± 0.0 20.0 ± 8.7 61.3 ± 9.2 24.4 ± 1.3 31.6 ± 0.9 Burn July 60.4 ± 5.3 22.5 ± 4.0 0.4 ± 0.4 0.0 ± 0.0 16.7 ± 8.5 92.0 ± 20.5 20.3 ± 0.9 25.9 ± 1.3 Control July 72.5 ± 6.9 14.2 ± 4.5 2.1 ± 1.4 0.0 ± 0.0 11.3 ± 5.5 96.1 ± 13.7 21.3 ± 1.3 28.8 ± 1.3 Mow July 49.0 ± 9.3 24.5 ± 8.3 8.0 ± 3.1 0.0 ± 0.0 18.5 ± 9.6 69.7 ± 6.0 23.0 ± 1.6 30.4 ± 1.6 Burn August 59.5 ± 6.8 26.5 ± 6.9 1.0 ± 1.7 0.0 ± 0.0 13.0 ± 4.5 124.0 ± 24.3 21.8 ± 0.7 26.9 ± 1.2 Control August 83.8 ± 5.9 9.6 ± 3.5 1.7 ± 1.2 0.0 ± 0.0 5.0 ± 3.0 115.8 ± 19.0 21.4 ± 1.2 27.3 ± 1.7 Mow August 63.0 ± 11.1 14.0 ± 2.3 7.5 ± 3.3 0.0 ± 0.0 14.5 ± 6.1 85.6 ± 5.5 24.2 ± 0.6 28.2 ± 0.9 ‡ Percents show the area of a 1 x 1 m quadrat covered by each ground cover component

27

Figure 1-1 Species accumulation curves for observed ant richness in praries under three management regimes per the total number of occurrences of all ant species. Error bars show 95% confidence intervals.

28

Figure 1-2 Rank abundance of all ant species present in prairies with different land management practices. The number of occurrences for each species shows the number of baits occupied by each species in each habitat type. Species are organized by total abundance in control sites.

29

Figure 1-3. Mean ant abudance across five months in prarie sites with different management. Ant abundace is measured by colony occurreces on baits by month.

30

Figure 1-4. Nonmetric Multidimensional Scaling (NMDS) of ant species similarity for each sampling month across all management types. April = red crosses, May = green x’s, June = blue squares, July = grey triangles, August = black dots. Ellipses represent 95% CI for each month, and each color corresponds to the month with the same color.

31

Figure 1-5. NMDS plot showing ant species similiarity between the three management types. Each point represents one plot, and the colors are as follows: burn = red crosses, control = blue squares, mow = green x’s. Ellipses represent 95% CI for each month, and each color corresponds to the month with the same color.

32

Figure 1-6. Canonical Correspondence Analysis biplot comparing ant species composition, relative abundace of 24 ant species, 8 environmental factors in 17 sites differing in prairie management during the month of April. The lines represent the environmental variables, codes represent the sites, and numbers represent the and species. Corresponding species numbers can be found in Table 1-3 and site codes in Table 1-1.

33

Figure 1-7. Canonical Correspondence Analysis biplot comparing ant species composition, relative abundace of 22 ant species, 7 environmental factors in 17 sites differing in prairie management during the month of May. The lines represent the environmental variables, codes represent the sites, and numbers represent the and species. Corresponding species numbers can be found in Table 1-3 and site codes in Table 1-1.

34

Figure 1-8. Canonical Correspondence Analysis biplot comparing ant species composition, relative abundace of 23 ant species, 8 environmental factors in 17 sites differing in prairie management during the month of June. The lines represent the environmental variables, codes represent the sites, and numbers represent the and species. Corresponding species numbers can be found in Table 1-3 and site codes in Table 1-1.

35

Figure 1-9. Canonical Correspondence Analysis biplot comparing ant species composition, relative abundace of 20 ant species, 7 environmental factors in 17 sites differing in prairie management during the month of July. The lines represent the environmental variables, codes represent the sites, and numbers represent the and species. Corresponding species numbers can be found in Table 1-3 and site codes in Table 1-1.

36

Figure 1-10. Canonical Correspondence Analysis biplot comparing ant species composition, relative abundace of 26 ant species, 7 environmental factors in 17 sites differing in prairie management during the month of August. The lines represent the environmental variables, codes represent the sites, and numbers represent the and species. Corresponding species numbers can be found in Table 1- 3 and site codes in Table 1-1.

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Talbot, M. 1954. Populations of the ant Aphaenogaster (Attomyra) treatae Forel on abandoned fields on the Edwin S. George Reserve. Contributions From The Laboratory of Vertebrate Biology, Univ. of Mich. 69: 1-9.

Talbot, M. 1966. Flights of the ant Aphaenogaster treatae. Journal of the Kansas Entomological Society 39: 67-77. ter Braak, C. J. F. 1986. Canonical correspondence analysis: A new eigenvector technique for multivariate direct gradient analysis. Ecology 67: 1167-1179.

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Chapter 2

Formica gynocrates (Snelling and Buren) and Dorymyrmex insanus (Buckley) encountered as new ants for Ohio

2.1 Introduction

The diversity of ants know to occur in Ohio has risen considerably in the last five years from 118 species (Coovert 2005) to 128 (AntWeb 2010, K. Ivanov, pers. comm.).

Presented here are two new state records of ants recently found in Ohio bringing the current ant richness total to 130 species. The two new species encountered are

Dorymyrmex insanus Buckley and Formica gynocrates Snelling and Buren.

The genus Dorymyrmex includes 12 described species in the United States

(Snelling 1995). Only one species of Dorymyrmex was previously known from Ohio:

Dorymyrmex grandulus Forel (Coovert 2005). Coovert (2005) mentioned that another species of Dorymyrmex (D. insanus) possibly occurred in Ohio, but had not yet been found. D. insanus was originally described by Buckley in 1866 as Formica insanus and has since gone through a series of taxonomic revisions, the most recent by Snelling in

1995. The range of D. insanus is from Kansas south to the central part of Texas and west to the southern portion of California (Snelling 1995). Other possible state records based on earlier revisions outside of this range came from Illinois (Gregg 1944, DuBois &

43 LaBerge 1988) and Indiana (Munsee et al. 1986). The limit of the southern extent of the range is even less clear because of difficulties in distinguishing D. insanus from the

Central American ant D. nigra Pergande that has a similar appearance and has been poorly collected (Snelling 1995).

The sanguinea group of the genus Formica consists of 11 North American species

(Hölldobler & Wilson 1990), four of which have been recorded in Ohio (Coovert 2005), and one, Formica gynocrates, that has been recently named (Snelling & Buren 1985). F. gynocrates has been recorded from Michigan, North Dakota, Wyoming, and Colorado

(Snelling & Buren 1985) and was thought to likely occur in Ohio.

2.2 Methods

Presented here for the first time in Ohio are D. insanus and F. gynocrates, extending the range of D. insanus into northeastern North America and the F. gynocrates further south into North America. The Ohio records for D. insanus are as follows: 1)

Ohio, Lucas County, Swanton, Oak Openings Preserve (41° 33’N, 083° 51’W), altitude

205 m, 11.viii.2009, col. R.L. Friedrich, 1 worker, tuna bait (vouchers deposited at the

University of Toledo, Dept. of Environmental Sciences), and 2) Ohio, Lucas County,

Swanton, Kitty Todd Nature Preserve (41° 37' N, 083°47' W) altitude 207 m,

17.viii.2009), col. R.L. Friedrich, 3 workers, tuna bait (vouchers deposited at the

University of Toledo, Dept. of Environmental Sciences).The Ohio records for F. gynocrates are as follows: 1) Ohio, Lucas County, Swanton, Kitty Todd Nature Preserve

(41° 33’N, 083° 51’W), altitude 207 m, 24.iv.2009), col. R.L. Friedrich, 1 worker, tuna bait (vouchers deposited at the University of Toledo, Dept. of Environmental Sciences.

44 The Oak Openings Metropark Preserve and Kitty Todd Nature Preserve are both part of the greater Oak Openings region. The parks within this region consist of five habitat types: wet prairie, sand prairies or barrens, oak flatwoods, and oak savanna. The sampling effort for this research was exclusively in the prairies. All sites selected were prairie sites within the two preserves that receive management (i.e. controlled burning or mowing) to maintain the prairie vegetation structure.

Seventeen sites were sampled for ants between the two preserves. The specimens were collected using a tuna baiting method. The baits were set up in a 14 x 14 m grid with 49 tuna baits equally spaced 2 m apart. After the baits were left out for 30 min all ant species on each bait were collected, stored in 70% ethanol alcohol and taken back to the lab for identification. The sites were resampled in the same plots over the course of five months (April 2009 to August 2009). D. insanus was collected at three of the seventeen sites (South Peils and Moseley Barrens at Kitty Todd and Badger Barrens at

Oak Openings Metropark) on 11, 17, and 18 of August 2009, respectively, and only occurred on eight total baits. It occurred on the same baits with four other ant species,

Aphaenogaster treatae Forel, Formica vinculans Wheeler, Dorymyrmex grandulus Forel,

Formica dolosa Buren. F. gynocrates was collected at only one site (South Peils) on 24

April and 13 August 2009 and occupied only three total baits. It occurred together with three other ant species, A. treatae, F. vinculans, and Paratrechina parvula Mayr.

All of the sites where D. insanus and F. gynocrates were collected had similar characteristics. All of the sites had very little if any leaf litter cover and few trees. The soil in the Oak Openings region is very sandy and ranged from around 90 to 93% sand for the four sites where the two new species were found (Web Soil Survey 2010). The

45 soil has rapid drainage and is very dry. The vegetation was also dry throughout the summer and included a sparse covering of various prairie grasses (average range of 30 –

65% cover in a 1 x 1 m quadrat) and forbs (10 – 30% cover). However, the vegetation cover was reduced in the Badger Barrens from a recent controlled burn and was also reduced in Moseley Barrens due to an early season mow. Both of these disturbances occurred in April 2009 before the first sampling date. Frequent management is common in the Oak Opening prairies, mainly to reduce growth of woody vegetation and to promote native prairie grass growth.

2.3 Recognition

2.3.1 Recognition of Dorymyrmex insanus

According to Snelling (1995) workers of D. insanus range from 2.7 to 3.4 mm in total length. The head length ranges from 0.90 to 0.97 mm and the head width ranges from 0.68 to 0.87 mm and in frontal view is slightly wider above the eye. The mesonotum is angulate with the posterior face of the mesonotum distinctly slanted. The head has a dense appressed pubescence covering its entirety separated from neighboring hairs by no more than twice the width of a hair. The pronotum has a pair of setae and the gaster has a scattering of setae mainly on the latter three turgites (Figure 2-1). The color of D. insanus ranges from a yellowish-brown to a brownish-black with the legs and antennae slightly paler. The gaster and head (except mandibles) are commonly darker than the alitrunk (Snelling 1995). In Ohio, D. insanus is difficult to differentiate from the similar species Dorymyrmex grandulus. These two species cannot be distinguished in the

46 field, but when examined under a microscope can be distinguished by the two setae on the pronotum of the D. insanus as well as the longer appressed pubescence on the head of the D. insanus (Snelling 1995, Coovert 2005).

2.3.2 Recognition of Formica gynocrates

According to Snelling and Buren (1985) workers of F. gynocrates appear to look similar to another ant of the sanguinea group, Formica pergandei Emery, but when examined more closely have differences in the shape and sculpture of the thorax and head. The adult workers are large ranging from 5.2 to 7.6 mm in total length. The head is longer than it is broad (length 1.39-1.97 mm, width 1.23-1.89 mm). In a frontal view of the head, the eyes protrude beyond the margins of the head for small workers, but not usually for larger workers (Figure 2-2). The antennal scapes are shorter than the head length. The pubescence is dense and appressed on antennal scapes and on upper portion of the thorax and abdomen. The color of the alitrunk, legs, petiole and head (including antenna and mandibles) are orangish-brown with a dull appearance. The gaster is dark brown to black with a satiny appearance. F. gynocrates can be distinguished from F. pergandei by the short length of the antennal scapes, somewhat convex promesonotal outline, and duller surface appearance (Snelling & Buren 1985). Queen and male descriptions and measurements vary from workers (see Snelling & Buren 1985 for details).

2.4 Discussion

D. insanus, commonly called the pyramid ant, is an aggressive ant and is highly

47 active in warm temperatures (Wheeler & Wheeler 1986). The common name pyramid ant refers to the unique mound of the nest (Coovert 2005). Workers are active around the nest and they often exhibit “erratic or crazy” behavior moving in a confused or unorganized fashion (Johnson 1989). When foraging, D. insanus tends to forage in lines (Wheeler &

Wheeler 1986). This ant is predaceous, but also utilizes honeydew-producing hemipterans as a food resource (Wheeler & Wheeler 1986, Johnson 1989).

D. insanus is one of the most common ant species in the southern United States

(Snelling 1995) and finding this species in Ohio was somewhat surprising because no individuals or colonies have previously been confirmed in the U.S. Midwest. The ability of the D. insanus to survive in this area of North America may be due to the unique habitat offered by the Oak Openings region. D. insanus prefers nesting in sandy soils and avoids wet areas with poor drainage (Johnson 1989). The species also favors nesting in sunny open areas such as prairies or deserts (Wheeler & Wheeler 1986). The sandy prairies in the Oak Openings region thus provide an ideal habitat for the species to thrive given the nesting conditions of D. insanus.

Formica gynocrates is a newly described species of the sanguinea group, has unique life history traits that may have allowed its survival and occupation of the Oak

Openings region. The sanguinea group is dulotic (slave-making), capturing pupae of other Formica species and rearing them as workers to serve their own colony (Snelling &

Buren 1985). F. gynocrates normally enslaves ants of the same genus, and in particular

Formica vinculans Wheeler and to a lesser degree Formica lasioides Emery (Snelling &

Buren 1985, Talbot 1985). Nests of F. gynocrates occur in open prairie habitats, but are limited to living in habitats with high abundance of their preferred host, F. vinculans

48 (Talbot 1985). F. gynocrates prefers nesting in sandy habitats and upland prairies with quick drainage and sparse vegetation covering the ground (Talbot 1985). This type of habitat is characteristic of the prairies in the Oak Openings Region. F. gynocrates tend aphids and also eat the brood of other ant species after nest raids (Talbot 1985). Finally, compared with other species of the sanguinea group, F. gynocrates vary from the other species by exhibiting higher tolerances to hot temperatures and behaving more aggressively while raiding nests (Talbot 1985). Tolerances to high temperatures allow F. gynocrates to forage or raid nests when other ant species may be disorganized. Nuptial flights of the F. gynocrates occur on hot days and both females and males do not fly in temperatures lower than 25° C (Talbot 1985).

The Oak Openings Region is a unique ecosystem for the Midwest, but is drastically understudied. The discovery of two new state record ant species is not surprising given the general lack of sampling effort and publications from this region.

Implementation of a more diverse and extensive sampling effort could lead to the discovery of additional ant or insect species that have not yet been recorded in Ohio.

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Figure 2-1 Worker head from a front view (1) and worker mesosoma and head in side view (2), illustration from Snelling 1995.

Figure 2-2 Worker head from front view and worker mesosoma in side view, illustration from Snelling and Buren 1985.

50 2.5 References

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DuBois, M. B. and W. E. LaBerge. 1988. Annotated list of ants in Illinois (Hymenoptera: Formicidae). pp. 133-156 in J. C. Trager (ed). Advances in myrmecology. E. J. Brill. New York.

Gregg, R. E. 1944. The ants of the Chicago region. Annuals of the Entomological Society of America 37: 447-480.

Hölldobler, B. and E. O. Wilson. 1990. The Ants. Harvard University Press, Cambridge, Massachusetts.

Johnson, C. 1989. Taxonomy and diagnosis of Conomyrma insana (Buckley) and C. flava (McCook) (Hymenoptera: Formicidae). Insecta Mundi 3: 179-194.

Munsee, J. R., W. B. Jansma, J. R. Schrock. 1986. Revision of the checklist of Indiana ants with the addition of five new species (Hymenoptera: Formicidae). Proceedings of the Indiana Academy of Science 95: 265-274.

Snelling, R. R. 1995. Systematics of Nearctic ants of the genus Dorymyrmex (Hymenoptera: Formicidae). Contributions in Science, Natural History Museum of Los Angeles County 454: 1-14.

Snelling, R. R. and W. F. Buren. 1985. Description of a new species of slave-making ant in the Formica sanguinea group (Hymenoptera: Formicidae). Great Lakes Entomologist 18: 69-78.

Talbot, M. 1985. The slave-making ant Formica gynocrates (Hymenoptera: Formicidae). Great Lakes Entomologist 18: 103-112.

Wheeler, G.C. and J. N. Wheeler. 1986. The Ants of Nevada. Natural History Museum of Los Angeles County California.

Web Soil Survey. 2010. http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx. (17 February 2010).

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