Risk Assessment of the Nonnative Argentine Black and White Tegu

Home , Key tegu, Salvator (lizard), Tegu

Risk Assessment of the Nonnative Argentine Black and White Tegu,

Salvator merianae, in South Florida

Liz Anne Barraco

A Thesis Submitted to the Faculty of

The Charles E. Schmidt College of Science

in Partial Fulfillment of the Requirements for the Degree of

Master of Science

Florida Atlantic University

Boca Raton, FL

May 2015

Acknowledgements

The author wishes to express thanks to the countless people who offered assistance and support throughout this project. This work would not have have been possible without the

thoughtful support, humor and friendship of Jenny Ketterlin Eckles. Dr. Colin Hughes

took me in as a student and gave me the opportunity to start over with something that interested and inspired me, I could not be more grateful. Jake Edwards provided, literally,

the legs of this operation during a very sticky time, unending field companionship and

some very thoughtful edits. Ashley Taylor was an incredible assistant with organizing

and catalouging diet items, no matter how stinky. Dr. Frank Mazzotti and his widllfie

crew at University of Florida provided field support, dead lizards and pizza which were

all equally appreciated. Jennifer Possley provided field expertise in the identification of multiple plant species. Lastly, and most importantly, my husband Jeff (the squirrel tamer) who never failed to be supportive, understanding and wonderful throughout this process.

iv Abstract

Author: Liz Anne Barraco

Title: Risk Assessment of the Nonnative Argentine Black and White Tegu, Salvator merianae, in South Florida

Institution: Florida Atlantic University

Thesis Advisor: Dr. Colin Hughes

Degree: Master of Science

Year: 2015

The Argentine black and white tegu, Salvator merianae, is a nonnative species that has invaded parts of Florida. The potential impacts of this species on native Florida wildlife are not yet known. This study looks at the stomach contents of 169 S. merianae captured between 2011 and 2013 in south Florida to infer potential impacts of S. merianae and spatial or seasonal shifts in diet. Analysis of 169 GI tracts showed that S. merianae is an omnivorous, terrestrial forager with a broad dietary range which includes insects, fruits, plants, snails, crayfish, carrion, birds, small mammals, turtles, snakes, lizards, frogs and eggs. S. merianae diet composition varied with capture habitat, the fattest tegus were collected from disturbed/agricultural areas and these samples contained, primarily, gastropods and insects. Tegu dietary habits threaten local endangered and state listed species such as the American crocodile, Crocodylus acutus, and the Cape Sable seaside sparrow, Ammodramus maritimus mirabilis. Dedicated funds

v and efforts need to be focused on this species to limit its further spread and future impact on native species.

vi Risk Assessment of the Nonnative Argentine Black and White Tegu,

Salvator merianae, in South Florida Tables ...... viii Figures ...... ix Introduction ...... 1 Methods ...... 10 Sample collection ...... 10 Diet analysis ...... 10 Variables ...... 12 Sex ...... 12 Size class ...... 12 Capture habitat ...... 13 Collection season ...... 14 Body condition ...... 15 Statistical analysis ...... 16 Results...... 18 Sample collection ...... 18 Diet description ...... 19 Resource use variation ...... 19 Spatial and Seasonal Variation in Population ...... 21 Discussion ...... 23 Spatial Variation in Diet ...... 24 Spatial and Seasonal Variation in Population ...... 26 Conclusion ...... 29 Literature Cited ...... 49

vii Tables

Table 1. Tegu collections by variable, 169 tegu samples ...... 33

Table 2. Frequency of occurrence (FO) of stomach contents, 169 samples ...... 34

Table 3. ANOSIM results for diet comparisons, plant and insect families ...... 35

Table 4. Pairwise ANOSIM results for diet comparisons, plant and insect families

among capture habitat ...... 36

Table 5. SIMPER results for diet comparisons among capture habitat ...... 37

Table 6. SIMPER results for plant family among capture habitat ...... 39

Table 7. SIMPER results for insect family among capture habitat ...... 41

Table 8. Person’s Chi-Square statistical results for contingency tables ...... 43

Table 9. Frequency of occurrence (FO) of stomach contents, 115 samples ...... 45

viii Figures

Figure 1. Map of proposed study area for S. merianae collection ...... 31

Figure 2. Map of actual S. merianae collections, icons indicate capture habitat ...... 32

Figure 3. Bar graphs of S. merianae sex and size class collections by month

And collection season ...... 44

ix Introduction

Invasions of new areas by nonnative species are a major conservation concern when they threaten native biodiversity and natural area resources (Simberloff 2011,

Hardin 2007, Devine 1998, Duffy 2009, Anderson et. al. 2004). A wide variety of nonnative species have spread into new areas, changing ecosystems and threatening biodiversity (Schmitz and Simberloff 1997, Simberloff 2013, Snow et. al. 2007).

Preserving biodiversity, against this and other threats, is important for many reasons including that systems with mixtures of species produce more biomass than systems with fewer species (Duffy 2009). Biodiversity can also serve as insurance to protect an ecosystem from drastic fluctuations in populations and production and maintain its overall stability (Hooper et. al. 2005, Loreau et. al. 2001). Additionally, native biodiversity has aesthetic, cultural, and economic importance, all which are threatened by invasions (Simberloff 2013).

While it can be easy to identify nonnative species, identifying species that are nonnative and invasive can be challenging; invasive species are those that spread into a natural environment and negatively affect the ecosystem (Lambertini 2011, Simberloff

2010). Impacts of invasive, nonnative species (hereafter ‘invasive species’) are second only to habitat degradation and destruction caused by humans (Wilcove et. al. 1998).

Fully 42% of the animals protected under the U.S Endangered Species Act are listed as endangered, at least in part, as a result of interactions with invasive species (Wilcove et. al. 1998). Invasive species also impose a high economic cost; managing invasive species 1 takes hundreds of millions of dollars from state and federal budgets annually, draining substantial resources from other conservation efforts (Anderson et. al. 2004, Pimentel et. al. 2004). Having continuous funding is imperative for adequately controlling a nonnative invasion, as gaps in control efforts allow invasive species to proliferate and return to previous levels (Simberloff et. al. 2005).

The impact of individual invasive species is challenging to determine and may not be assessed until eradication is no longer a viable option (Anderson et. al. 2004,

Simberloff 2014). To ameliorate negative effects of invasive species, the impact of newly established populations should be assessed, and resources directed to the most threatening examples.

Threats to biodiversity arise from direct and indirect effects of invasive species.

Direct impacts are a result of direct interaction between species and include predation, habitat displacement and increased competition for limited resources (Mack et. al. 2000,

Simberloff 2001, Simberloff et.al. 2013). Indirect impacts arise as interactions filter through species or trophic levels, like soil chemical levels, nutrient variation or exploitation, can also have significant negative effects on species and the ecosystem; many species impose both direct and indirect effects (Simberloff et. al. 2013, Anderson et. al. 2004, Ehrenfield 2010, Simberloff 2011, Wootton 1994). For example, the brown tree snake, Boiga irregularis, has had significant direct impacts on Guam’s native fauna since invading and establishing; predation by the snake has caused the extirpation of over

50% of Guam’s native breeding bird species (Rodda and Savidge 2007). This loss of pollinators and seed dispersers has had cascading indirect effects in the Guam ecosystem, including reduced seed set and seedling recruitment for bird-pollinated plant species,

2 compared with a nearby island which had not been invaded by the brown tree snake

(Mortensen et. al. 2008).

While invasive species are a global problem, the State of Florida is a veritable hotbed for invasive species. With 439 known introduced animal species, of which 123 are believed to be reproducing and thus are considered established, the State of Florida is host to more nonnative wildlife species than any other state (Hardin 2007, Meshaka et. al.

2004). Climate, geography and international trade play a large role in the introduction and establishment of nonnative species in Florida (Schmitz and Simberloff 1997, Hardin

2007). As a peninsula, a large portion of Florida is geographically separated from areas with comparable habitat and climate; this separation means that many species not naturally present in Florida are well-suited to thrive in the tropical and subtropical climate (Hardin 2007, Engeman et. al. 2011).

In addition to nonnative agricultural pests and nonnative plants, Florida has a particular problem with the establishment of nonnative reptiles (Engeman et. al. 2011,

Kraus 2009, Krysko 2011, Fujisaki et. al. 2010). Between 1999 and 2010, over 482 million imported live animals were brought into the United States through Florida entry points, over 9 million were species of reptiles (Romagosa 2011).Reptiles make up almost

30% of the nonnative species established in Florida, more than any other category

(Hardin 2007). Green iguanas, Burmese pythons, red-headed agamas, black spiny-tailed iguanas, Boa constrictors and Cuban knight anoles (Iguana iguana, Python bivittatus,

Agama, agama, Ctenosaura similis, Boa constrictor and Anolis equestris) are a few examples of well-known nonnative reptiles established in Florida (EDDMapS 2015,

Krysko 2011, Engeman et. al. 2011). There are almost three times as many nonnative

3 lizard species (n = 43) as there are native lizard species (n = 16) in Florida (Krysko

2011).

Many of the nonnative reptiles established in Florida are present as a result of their popularity in the exotic pet trade (Hardin 2007). Almost 90% of Florida’s nonnative reptile and amphibian species have been introduced as a result of the pet trade industry

(Krysko 2011). The State of Florida offers a hospitable climate for reptile breeders to house animals outdoors during most, if not all, of the year. Some breeding facilities are poorly maintained and escapees from them can be a source of entry for nonnative species.

Many nonnative lizard sightings and established populations are adjacent to known reptile dealership facilities (Hardin 2007, Enge 2007). In addition to breeding facilities, overall availability and popularity of some species as pets can lead to a large population of owners who lack education and understanding to properly maintain care of the animal for the duration of its life. In many instances, the outcome can be the release or escape of the animal into a natural area. Historically, introduction of nonnative vertebrate species tended to be the result of intentional releases; 62% of the established reptile and amphibian species in Europe were determined to be the result of deliberate releases

(Hulme et. al. 2008). While every released animal does not immediately, or even often, become an established threat, intentional and repeated release of healthy nonnative specimens increases the opportunity for establishment (Hulme et. al. 2008).

Recently, another exotic species of lizard has become established in Florida, the

Argentine black and white tegu, Salvator merianae, formerly Tupinambus merianae

(Harvey et. al. 2012). This lizard is a member of the Teiidae or whiptail family that can grow to over 1.2 meters in length, weigh up to 8 kg and live up to 20 years (Enge 2007).

4 Tegus are primarily terrestrial, though they are capable swimmers and can stay submerged for an extended period of time (Olmos 1995). Their native range spans northern Argentina, eastern Paraguay, Uruguay and a portion of southeastern Brazil

(Presch 1973), covering a range of altitudes (up to 1250 m) and landscapes including evergreen forest, deciduous woodlands, grasslands and scrub areas (Presch 1973). Within these biomes, S. merianae is found to be most abundant in open clearings and disturbed areas (Bovendorp et. al. 2008). During winter periods, S. merianae brumates in aggregations utilizing burrows or other hibernacula (Winck and Cechin 2008). Adult, male tegus are generally the first to emerge from their burrows, followed by adult females and then subadults over a period of several months (Winck and Cechin 2008).

This temporal difference between male and female emergence is common among reptiles and allows male tegus the opportunity to establish territories before the females emerge

(Winck and Cechin 2008). Sexual activity between tegus begins shortly after females emerge from brumation (Noriega et. al. 2002). Once they reach reproductive size, female tegus can lay one clutch of approximately 30 eggs each year (Yanosky and Mercolli

1991).

S. merianae is an omnivorous lizard with a broad diet that contains items from multiple trophic levels (Mercolli and Yanosky 1994, Kiefer and Sazima 2002). Detailed diet studies on adult and juvenile tegus have yielded specific information on prey in their native range. In a 1994 study, Mercolli and Yanosky, analyzed the stomach contents of

70 adult S. merianae lizards while Kiefer and Sazima looked at the stomach contents of

35 juvenile tegus in 2002. In juvenile S. merianae, invertebrates were the most frequently found diet item, particularly species of Coleoptera, Hymenoptera, Araneae and

5 Orthoptera (Kiefer and Sazima 2002). Adult tegus were found to be 71% herbivorous and 29% carnivorous (Mercolli and Yanosky 1994). In adults, common diet items were fruits, snails, Lepidoptera, Coleoptera, lizards, and small mammals (Mercolli and

Yanosky 1994, Kiefer and Sazima 2002). Together, these two studies may illustrate an ontogenetic diet shift linked to the differentiation of teeth in S. merianae over time

(Presch 1973). Diet items indicate that this animal is an opportunistic, terrestrial, omnivorous forager (Mercolli and Yanosky 1994, Kiefer and Sazima 2002).

Additionally, research testing germination rates of seeds ingested and passed by tegus suggests that S. merianae may play an important role as a seed disperser while foraging

(Castro and Galetti 2004). In both juvenile and adult studies, mildly toxic species of

Lepidoptera and Diplopoda were found as common diet items suggesting that S. merianae is immune to such toxic secretions (Mercolli and Yanosky 1994, Kiefer and

Sazima 2002). Additionally, the presence of flies associated with carrion and direct observations confirm that S. merianae occasionally participates in necrophagy (Kiefer and Sazima 2002).

Despite its spread as an invasive species in Florida and islands off of Brazil, S. merianae is now listed as an Appendix II Convention on Trade Endangered Species of

Florida and Fauna (CITES) species meaning that international trade of their species is becoming more regulated (Winck and Cechin 2008, Basso et. al. 2005). This addition to the CITES list comes as a result of the heavy trade from South America, the export of some 1,900,000 tegu lizards or products a year, mostly as skins for boots and other novelties (Fitzgerald 1994). Tegus are an important resource for indigenous people in

6 South America; the fat and meat of the tegu can be eaten and the skin can be sold or bartered (Fitzgerald 1994, Norman 1987).

The Argentine black and white tegu was brought to Florida through direct importation from Paraguay for the pet trade (Enge 2007). The species became popular among breeders and was captive bred in multiple locations throughout Florida (Enge

2007). The first confirmed sighting of a free-living tegu in south Florida, (Miami-Dade

County) occurred in 2007 though earlier sightings, 2006, of a separate population established in West Central Florida exist (EDDMapS 2015, Hardin 2007). The population of S. merianae present in Polk and Hillsborough counties is likely the result of an intentional release of imperfect specimens (i.e. missing toes, broken tails) from a reptile breeder (Enge 2007). While not established, S. merianae has successfully overwintered in the Florida panhandle in Panama City; low temperatures within Florida will not limit the distribution of S. merianae (EDDMapS 2015). Presence points from South America show that S. merianae can survive almost as far south as 40°S latitude, and while other factors would need to be considered, a similar range in North America would place the northern most edge as far north as West Virginia (Lanfi et. al. 2013). A 2007 video documentary shows Argentine black and white tegus being raised and bred outdoors, over winter, in central Alabama (Langerwerf and Langerwerf 2007).

The invasion of a nonnative species into a new area can be considered in four stages: entry of the species, establishment of a population; spread; and impact on native ecosystem (Anderson et. al. 2004). To be considered established “evidence of reproduction”, such as females with fertilized eggs, evidence of nests or an assortment of size classes, must be present (Meshaka et.al. 2004). In Florida, the Argentine black and

7 white tegu has progressed through three of these four stages: entry through the pet trade, establishment after accidental or deliberate release, and spread. Spread of the species in south Florida within the last few years has been roughly documented by EDDMapS, the online Early Detection and Distribution Mapping System (EDDMapS 2015). Developed by the University of Georgia, citizens can report sightings of nonnative species which are then confirmed by biologists from multiple state and federal agencies using photographic evidence (EDDMapS 2015). The software has been used mainly to map nonnative plant species throughout the country, but the database has been expanded to accept and map sightings of nonnative animals in Florida (EDDMapS 2015). In addition to EDDMapS reports, exotic species sightings are also reported to the Florida Fish and Wildlife

Conservation Commission (FWC) Exotic Species Hotline (888-Ive-Got1), data from both are stored in a collective FWC database. Sightings of S. merianae in south Florida date prior to the first confirmed report in 2007, establishment of the species was secured in the following years resulting in increasing frequency of sightings (EDDMapS 2015). As further evidence of establishment, the first observation of tegus nesting in South Florida was documented in 2011 (Pernas et. al. 2012). Though tegus are established and spreading in south Florida, control efforts have been limited because resources are targeted at more publicized invasive species such as large constrictors. It is necessary to assess impacts that S. merianae will have on native Florida species because the magnitude of the threat will, in part, determine how control efforts should be prioritized.

One way of measuring the direct impact an invasive species has on other species is by analyzing stomach contents. This project compares stomach contents of collected S.

8 merianae with information on the location and date of their capture in order to infer their ecological impact. Goals of this project are:

(1) characterize the diet of S. merianae in South Florida through stomach contents analysis to infer potential impact on Florida native species

(2) identify seasonal and spatial variation in diet, body condition, sex and size class of tegu population.

9 Methods

Sample collection

Tegus captured for this study were collected by FWC and University of Florida

(UF) from March 2012 to October 2013. These lizards were collected via hand capture, capture in a cage style trap, removed dead from the side of the road, or shot with a 12 gauge shotgun during survey. Traps set for tegus were baited with whole chicken eggs.

Upon collection, a GPS waypoint of the trap, or specimen, was recorded. Tegus collected live were humanely euthanized by UF or FWC biologists within six hours of capture using a captive bolt stunner, a .22 caliber rifle, or a 12 gauge shotgun. Euthanized tegus were then placed individually in plastic bags and frozen, or immediately necropsied by

UF biologists. Before necropsy, frozen specimens were thawed in room temperature water. Snout vent length (SVL), distance from snout tip to edge of vent, was measured to the nearest centimeter (Meshaka et. al. 2004). Weight of the entire animal was measured to the nearest gram using a Pesola scale, specimen sex was identified and recorded.

During necropsy, the intestinal tract was removed at the esophagus, emptied in its entirety into a plastic bag and frozen at 20° C until content analysis was performed.

Diet analysis

Prior to analysis, frozen samples were thawed at room temperature for handling.

Contents were rinsed with deionized water through a 1mm sieve and placed in a plastic petri dish. Samples were allowed to air dry before separating contents; food items were 10 then identified to lowest possible taxonomic category. Non-food items such as rocks and plastic were also recorded.

Items were identified by experts from Miami-Dade County Parks and Open

Spaces, Florida Department of Agricultural and Consumer Services, Fairchild Tropical

Botanic Garden, FWC, and UF. To assist in identification of seeds, field collection was done in tegu capture areas to identify fruiting species present and create a reference collection.

As a result of the diversity and varying condition of items found in the GI tracts, data collection focused on identifying items and recording frequency of occurrence following Rosenberg and Cooper (1990). Thus, items were only recorded as having occurred in a sample regardless of the quantity found of that item. This is a suitable method for instances when not all food items can be enumerated (Rosenberg and Cooper

1990).

Items identified were separated into nine categories, six of which were used in statistical analyses. Eggs found in samples were separated into two categories, those which could potentially have been bait used as an attractant and those, such as reptile eggs, which were not. Presence of fruit was determined by the presence of associated seed or shell. Gastropods found in diets were difficult to identify to species, often only slivers of the shell or operculum were present; gastropods were only listed as being present in a diet and not identified to species. Any vegetation that was not able to be identified as part of a fruiting body (i.e. seed or fruit skin) was considered incidental and categorized as leaf litter. Frequency of occurrence (FO) was calculated for each item

11 overall and for each individual category. FO was also calculated for sets of variables.

Variables were sorted into a table to illustrate frequencies among each (Table 1).

In addition to data gathered from animals captured and necropsied for this study,

GI tract data from tegus captured and necropsied the prior year (March 2011 – September

2011) was donated to this study. Data were compiled and included in statistical analysis.

Animal capture and data collection methods for the 2011 sample set were similar to those used in 2012-2013. This sample set will be referred to as 2011 data while the original sample set will be referred to as 2012-2013 data. Diet information for the 2011 tegus was only included in the nine overall categories as individual food items were not always identified to species.

Variables

Sex

During necropsy, the sex of each specimen was identified by the presence of reproductive organs (i.e. testes or ovaries). Animals were labeled as male, female or unknown sex. Animals of unknown sex lacked developed or identifiable reproductive organs.

Size class

While SVL of animal was measured in a continuous manner, measurements were divided into size classes, juvenile or adult, for use in the statistical modeling software.

Following earlier researchers, all tegus over 30 cm SVL in length were categorized as

12 being adult while those under 30 cm SVL were considered juvenile (Yanosky and

Mercolli 1992, Mercolli and Yanosky 1994, Kiefer and Sazima 2002).

Capture habitat

The study area for data collection is an approximately 65 square kilometer area located east of Everglades National Park (ENP), west of Florida Power and Light (FPL)

Turkey Point mitigation area, and north of Key Largo (Figure 1). The core of the S. merianae population is within this collection area. The populations northern edge lies somewhere in Florida City south of Palm Drive though more recently sightings have been coming in north of Palm Drive but west of urban development (EDDMapS 2015). At this time the population is only known to be established on the mainland of Florida

(EDDMapS 2015). The environment in the area of the core tegu population is varied so areas were partitioned into different habitat categories: natural, disturbed/agricultural and urban areas. All tegus used in this study were assigned a habitat category based on what habitat constituted the majority in a 0.5 km radius from the collection point.

Natural areas were comprised mainly of South Florida Water Management

District (SFWMD) lands located south of Florida City between Card Sound Road and the eastern boundary of ENP. These areas are a series of upland levees surrounding shallow

Everglades’ marsh. Levee areas are dominated by woody plant species such as cocoplum, wild coffee, sabal palm and poisonwood (Chrysobalanus icaco, Psychotria nervosa,

Sabal palmetto and Metopium toxiferum respectively) while lowland areas support sawgrass, pickerel weed, broadleaf arrowhead and similar wetland species (Cladium jamaicense, Pontederia cordata and Sagittaria latifolia respectively),

13 Disturbed/agricultural areas were comprised of lands north of the SFWMD lands and south of Florida City. Upland species, similar to those listed before, are present along the periphery but also included seasonal agricultural produce (i.e. tomato, squash, etc.) and large amount of weedy species such as Brazilian pepper, castor bean and papaya

(Schinus terebinthifolius, Ricinus communis and Carica papaya respectively). Depending on season fields in this area might have minimal cover or vegetation as crops were harvested and fields were prepared for planting.

Urban areas were comprised of developed areas such as a mobile home park or similar high-density neighborhoods. The vegetation in this category was more varied and included exotic landscape plants from all over the world. Most common species include members of the Arecaceae family such as queen palms and royal palms (Sygarus romanzoffiana and Roystonia regia). Most tegus collected from urban areas were captured in two mobile home parks, Gateway Estates or Goldcoaster, on the southern edge of Florida City.

Collection season

For analysis, four distinct three-month long categories were identified based on seasonality of tegu behavior: brumation, emergence, breeding, and dispersal. To compare seasonal behavior with research performed south of the Equator, seasons were matched by aligning January in Florida to July in South America and so on. For clarity, the following descriptions are explained with reference to the months of the year north of the

Equator. The brumation season covers the time period of November through January.

During brumation tegus have reduced activity and spend most of the time in hibernacula

14 (Winck et. al. 2011). Following brumation, the emergence period spans February through

April. During this period, male tegus leave hibernacula and overall tegu activity is increased from the preceding period (Winck and Cechin 2008). The third time period, breeding, represents May, June, and July. This ‘season’ shows increased presence of female tegus; tegu activity is highest during this period, mostly related to reproductive activities, though it decreases towards the end (Winck et.al. 2011). The final collection season, dispersal, includes the remaining months, August through October. During this period, tegu activity is still present but declining as the colder months approach and tegus disperse throughout the terrain (Winck et.al. 2011).

Body condition

Body condition was calculated by using residual index (RI) which is considered an appropriate method for terrestrial species (Jakob et.al. 1996, Băncilă et.al. 2010).

Residuals were calculated using body mass and length, in this case snout vent length

(SVL). Data was transformed using natural logs and body mass was regressed on SVL.

Using RI produced positive and negative residuals which are interpreted as the animal being in better or worse condition, respectively, than average (Jakob et.al. 1996). For statistical analysis, the residuals were broken up into categories: emaciated, thin, average, robust, and obese. Average lizards had residual scores close to zero, between -0.049 and

0.049. Robust animals had a score of 0.05 to 0.15 and obese animals were any with residual scores larger than 0.15. Thin animals had a residual score of -0.05 to -0.15 and emaciated animals were any with a score smaller than -0.15.

15 Statistical analysis

Multivariate analysis testing dietary similarity among different variables (size class, season, habitat, sex and body condition) was performed on the compiled presence- absence data using PRIMER 6 software (Clarke and Warwick 2001). The analysis of similarities (ANOSIM) was used to identify statistically significant diet variation among the pre-determined variables. ANOSIM is a permutation test which randomizes data hundreds of times, in this case 999 permutations were run. Actual data is then analyzed and variation, unlikely to be caused by random distribution, is detected (Clarke and

Warwick 2001). ANOSIM results include a Global R value and P value which are used to indicate the level of difference and the statistical significance of the result; Global R values range from 0 to 1, values closer to 1 indicate dietary differences between groups.

A SIMPER or similarity percentages test was run on any variable with a significant

ANOSIM p-value. SIMPER results quantify similarity contributions within groups and dissimilarity between groups. Secondary ANOSIM and SIMPER tests were run on variables with significant ANOSIM results using the 115 sample set where presence absence data had been changed from diet categories to insect and plant families.

To identify seasonal or habitat differences, categorical variables were tested for variance with either collection season or capture habitat using two-way contingency

tables. The contingency table combined with Pearson’s Chi-square statistic,

, determined whether the variables were independent of

each other (Gotelli and Ellison 2004). This statistical analysis was completed using

Microsoft Excel 2007, P-values for scores were determined using the Chi-

Square critical value table (Zar 1996) The P-value represents the probability of obtaining

16 the calculated result, P-values less than or equal to 0.05 are generally considered significant enough to reject the null hypothesis (Gotelli and Ellison 2004).

17 Results

Sample collection

300 tegus were captured during the 2012-2013 study period. Additionally, data from 78 tegus captured in 2011 was included. Tegus missing any data required for analysis (i.e. capture location, date, SVL, etc.) were removed from further analysis.

Tegus captured opportunistically in areas outside of the study range, usually in urban areas, were included if collection data were complete. 169 tegus had complete data and were used in analyses, 115 were part of the 2012-2013 capture effort and 54 were from

2011, collection points for these tegus are shown in Figure 2.

Among the 169 tegus there were 83 female, 82 male and 4 juveniles of unknown sex; 4 individuals lacked GI tract contents. The sample set contained a wide distribution of animals from each size class (79 juvenile; 90 adult), habitat (64 disturbed/agricultural;

71 natural; 34 urban) and body condition (26 emaciated; 33 thin; 51 average; 36 robust;

23 obese). The distribution of collection season was more varied (41 emergence; 91 breeding; 32 dispersal; 5 brumation). Due to the small sample size of tegus collected during the brumation season and tegus of unknown sex, these categories were not included during contingency table analysis though they were incorporated in multivariate analysis and appendix charts.

18 Diet description

Six food categories were identified as diet items and used in analyses:

Crustaceans, Gastropods, Insects, Fruits, Vertebrates and Eggs. Looking at all 169 tegu samples, contents most frequently included insects, fruits, gastropods, and vertebrates

(Frequency of occurrence, FO: 76%, 50%, 46%, and 37% respectively). Few samples contained evidence of eggs (10%) or crustaceans (5%). Leaf litter, possible bait eggs, and non-food item categories (39%, 11%, and 6%) were not used in statistical analysis.

Frequency of occurrence (FO) numbers for the overall data set, 169 tegus, by variable can be found in Table 2.

For the 115 diets collected in 2012-2013 (Table 9), the most frequently found insects were lubber grasshoppers, Romalea guttata, (47%), and ground beetles of the

Carabidae (14%) and Scarabaeidae (13%) families. Seeds from the cocoplum bush, (C. icaco, 17%) and palms, Arecaceae (18%) family, were most common. Additionally, seeds from the Anacardiaceae family, which contains the poisonwood tree (M. toxiferum) and Brazilian pepper (Schinus terebinthifoliius), were found in 14% of diet samples. The most common vertebrates found were mammals (19%), and especially members of the

Cricetidae family (10%) such as the hispid cotton rat, Sigmodon hispidus. Reptiles, amphibians, birds, and unknown vertebrates were also present (6%, 4%, 2%, and 3% respectively).

Resource use variation

Diet composition varied among habitats (ANOSIM, R = 0.201, p = 0.001).

Pairwise tests in ANOSIM showed that resource use in all habitats differed

(disturbed/agricultural vs. natural, R = 0.226, p = 0.001; disturbed/agricultural vs. urban,

19 R = 0.211, p = 0.001; natural vs. urban, R = 0.160, p = 0.001; Table 4). SIMPER results showed that natural and urban areas were 56% dissimilar while disturbed/agricultural areas had an overall 55% dissimilarity with natural and urban areas (Table 5).

Differences in consumption of insect, plant and gastropods contributed to >70% of dissimilarity between urban tegus and tegus in the other two habitats (Table 5). More than half of the dissimilarity between tegu resources in disturbed/agricultural areas and natural areas was caused by variance in gastropod and plant consumption (Table 5).

Consumption of plant species varied only by habitat (ANOSIM, R = 0.0095, p =

0.001, Table 3b). Differences were only truly significant between natural and disturbed/agricultural habitats (R = 0.128, p = 0.001) or natural and urban habitats (R =

0.095, p = 0.001, Table 4). Cocoplum, C. icaco, and fruits from the Arecaceae family contributed to most of the dissimilarity between these two sets of habitat categories

(Table 6). Chrysobalanus icaco was present in 30% of natural area samples and completely absent from samples collected in urban or disturbed/agricultural areas. In contrast, seeds from Arecaceae were present in 29% of urban area samples, 20% of disturbed/agricultural samples and only 6% of natural area samples. The Anacardiaceae family contributed 15% to the diet composition dissimilarity between natural and urban areas; natural areas had Anacardiaceae in 20% of samples compared to only 9% of urban samples.

Distribution of consumed insect species varied only by capture habitat (ANOSIM,

R = 0.288, p = 0.001, Table 3c). Differences were only truly significant between natural and disturbed/agricultural habitats (R = 0.379, p = 0.001) or natural and urban habitats (R

= 0.283, p = 0.001). Lubber grasshoppers, R. guttata, contributed most to the

20 dissimilarity between the two sets of habitat categories (Table 7). Romalea guttata was found in 70% of samples collected from natural areas compared to only 18% or urban samples and 13% of disturbed/agricultural samples. The second highest contributors to dissimilarity were insects from the Carabidae family which were found more frequently in disturbed/agricultural (40%) and urban samples (18%) than in natural area samples

(6%).

No ontogentic shift in diet was detected (ANOSIM, R = 0.005, p = 0.226). Tegu diet did not vary significantly between sexes (ANOSIM, R = -0.002, p = 0.564) or body condition (ANOSIM, R = 0.013, p = 0.186). There was no significant seasonal variation in overall diet composition (ANOSIM, R = 0.039, p = 0.089) though some pairwise tests showed near significant p values, particularly those including the brumation period

(emergence vs. brumation, R = 0.369, p = 0.008; breeding vs. brumation, R = 0.333, p =

0.011; dispersal vs. brumation, R = 0.370, p = 0.006). Without brumation there was no seasonal effect (emergence vs. breeding, R = 0.018, p = 0.281; emergence vs. dispersal, R

= 0.04, p = 0.053; breeding vs. dispersal, R = -0.007, p = 0.55).

Spatial and Seasonal Variation in Population

Tegu body condition varied across habitat categories (

. The majority of the 64 tegus collected from disturbed/agricultural areas had an average, or above, body condition (Em 9%; Th 8%; Av 19%; Ro 38%; Ob 27%).

Tegus with an above average body condition were less common in natural (Em 17%; Th

25%; Av 41%; Ro 8%; Ob 8%) and urban (Em 24%; Th 29%; Av 29%; Ro 18%; Ob

21 0%) areas. Distribution of size class and sex were similar in each habitat

The number of tegus collected from each habitat varied by season (

). Tegus collected during the emergence period were most frequently from disturbed/agricultural areas (D/A 76%; N 22%; U 2%) while dispersal period collections were most common in natural areas (D/A 16%; N 72%; U 13%).

Size class distribution differed among collection seasons (

). Smaller tegus were found more frequently than adult tegus in later months (Emergence: Juv 32%, Ad 68%;

Breeding: Juv 55%, Ad 45%; Dispersal: Juv 75%, Ad 25%).

Body condition varied throughout the year

). The majority of the 41 tegus collected during the emergence period had an above average, robust or obese, body condition (Em 7%; Th 15%; Av 24%; Ro 32%; Ob

22%). Tegu body condition deteriorated during the breeding season (Em 24%; Th 20%;

Av 27%; Ro 18%; Ob 11%); 85% of all emaciated tegus were found during the breeding season. While more tegus were captured during the breeding season (n = 91) than any other period, every other body condition had less than 55% of its sample set collected during that same period (Em 85%; Th 55%; Av 49%; Ro 44%; Ob 43%).

There was no variance in sex of tegu among collection seasons (

. P-values for all contingency tests are reported in Table 8.

22 Discussion

The Argentine black and white tegu is a terrestrial forager with a broad dietary range that includes items from multiple trophic levels. The most frequently found items were insects, plants and gastropods. The most common representatives of each category were those which generally had high abundance in the landscape. Tegus readily consume common terrestrial insects such as Scarabidae and Carabidae ground beetles and grasshoppers from Acrididae and Romaleidae. Fleshy fruits such as cocoplum, sabal palmetto (Sabaleae palmetto) and berries from poisonwood trees were also found in many diets. The most commonly found gastropods were Cuban brown snails, Zachrysia provisoria, a common garden and agricultural pest in south Florida (Capinera 2013).

Many vertebrates found in samples had been eaten relatively whole; separate samples contained a whole adult leopard frog, a whole snake and an intact hatchling turtle. Some tegu samples contained items which suggested necrophagy; in one, hair from a domestic cat (Felis catus) was found though no bones were in evidence. Another sample contained one large bone from a native turtle and a third contained a single leg from a wading bird. These samples with only parts of a whole diet item suggested that tegus fed on carrion.

While eggs, aside from those used as bait, were found at low frequency it is likely that this was skewed by the way tegus eat eggs. Tegus are known to break eggs and lap out the insides without consuming the shells; this would leave no identifiable material in the stomach (Langerwerf and Langerwerf 2007). Smaller eggs are eaten whole; most of

23 the non-bait eggs identified in this study were small reptile eggs which were found nearly whole in the stomach. Eggs are a common diet item for this lizard species; for example, a

2008 study, found evidence of S. merianae predation on eggs from 11 out of 30 artificial, ground nests (Bovendorp et. al. 2008). In their native range, tegus are known to invade chicken houses and consume both chicken eggs and newly-hatched chicks (Norman

1987).

Although combined results from previous studies, one focused on juveniles and the other on adult tegus, suggest an ontogenetic shift in diet, I did not find any evidence for an ontogenetic diet shift in the south Florida tegu population (Mercolli and Yanosky

1994, Kiefer and Sazima 2002). While not found to be statistically significant in the multivariate analysis, adult tegus consumed more vertebrate species than juvenile tegus; vertebrate remains were detected in 46% of adult tegu samples and only 29% of juvenile samples. Adult tegus may be better equipped to handle larger prey items such as vertebrates.

Spatial Variation in Diet

In south Florida, habitat affects diet composition and overall body condition of tegus. Samples collected from disturbed/agricultural areas were most similar to each other in diet composition and included the majority of tegus with an above average body condition. Tegu gut contents in disturbed/agricultural areas were made up primarily of gastropods and insects, largely ground beetles and Acrididae grasshoppers. Samples from areas where body condition was lower, (i.e. natural areas) had fewer gastropods and more seeds present (Table 2). Snails may have a higher overall abundance in

24 disturbed/agricultural areas in response to agricultural farming; this could make it easier for the lizards to ingest more calories with less exertion. While quantities of diet items were not recorded, GI tract samples from disturbed/agricultural areas often had multiple snails present suggesting that they are an important diet item. Additionally, lubber grasshoppers, R. guttata, were absent from most disturbed/agricultural samples though present in great numbers in natural area samples where most specimens had a below average body condition. Although R. guttata was the largest invertebrate commonly consumed by tegu the correlation between high R. guttata use and low body condition suggests that lubber grasshoppers do not make tegus heavier and may be a relatively poor resource. In disturbed/agricultural areas, non-lubber grasshoppers from the Acrididae family were the second most frequently consumed insect and were present in 20% of samples. In combination with Carabidae ground beetles, which were found in 40% of disturbed/agricultural samples, these non-toxic insects may have provided a better resource resulting in better overall body condition.

Results from this study show that tegus in disturbed/agricultural areas have better body condition than those found in natural or urban areas. Disturbed/agricultural areas may provide access to diet items or habitat conducive to producing heavier tegus. Tegus with an above average body condition would have higher reproductive potential resulting in increased clutch size or more fit offspring (Cruz et. al. 1999). Increased offspring dispersing from this area would impact surrounding areas and further invasion to adjacent areas is likely. Disturbed/agricultural areas make up the northwest portion of the established tegu habitat in south Florida, if the most ‘fit’ tegus are in this area than they

25 are more likely to successfully reproduce and have offspring spread beyond the current established population into unoccupied areas to the north and west.

Spatial and Seasonal Variation in Population

In south Florida, smaller tegus were collected more frequently in later months.

Tegus collected during the emergence period were more than twice as likely to be adult than juvenile. Additionally, those found during the dispersal period were almost three times more likely to be juvenile specimens. These results (Figure 3) marry well with the current understanding of the Argentine black and white tegu biological cycle; at the beginning of the emergence period, adult tegus come out of brumation and begin to forage and build up energy for breeding season (Winck et. al. 2011). After breeding, larger tegus have reduced activity and younger, juvenile, tegus are more common in the landscape, including those hatched during the previous season (Winck and Cechin 2008).

Adults seemingly disappear from the landscape as their activity levels decrease and they stay closer to burrows after the breeding season.

The number of tegus collected from each habitat varied by season. The association between collection season and habitat may have more to do with sample collection than biological behavior, especially in urban areas. Most tegus collected in urban areas were captured in traps set after someone reported a sighting; few traps were stationed more than a few weeks in urban areas. While tegus are active February through

October, their activity level is highest, making them more noticeable during the breeding season from month to month. Only 2% of emergence tegus and 13% of dispersal tegus were found in urban areas compared with 30% of breeding period tegus collected from

26 urban areas. Tegus are less active at these times, therefore less likely to be noticed and reported by people. Another noticeable difference that results from study methodology, is the number of tegus collected during the dispersal season from disturbed/agricultural areas, 8%, compared to emergence (48%) and breeding (41%). 77% of the tegus collected from disturbed/agricultural areas were part of the 2011 data. The 2011 trapping effort was focused in a disturbed area and was run from March to the first week of September which skews the number reported from disturbed/agricultural areas throughout the year, particularly in fall and winter months.

Body condition varied among collection seasons with two specific relationships: above average tegus were collected with the highest frequency during emergence and below average tegus were most common during breeding. Part of this result is a consequence resulting from the majority of disturbed/agricultural area tegus (i.e. the most robust and obese) being collected during the emergence period. The second piece, emaciated and thin tegus being collected with the highest frequency during the breeding season, is biologically interesting. I think this data illustrates a biological shift in tegu behavior; reserves are used during breeding season to find a mate and consummate reproduction. Additionally, female tegus are faced with the physical challenge of developing, laying and maintaining a nest during this period.

There was however, no significant variation in sex with collection season; male and female tegus were collected with similar frequency throughout the year while all tegus of unknown sex were collected during the dispersal period. This latter reflects our inability to sex individuals with undeveloped gonads. Collection of similar numbers of male and female tegus is unexpected in light of the documented variation in time of

27 emergence from brumation; this would predict a male bias during early emergence, followed by appearance of females. Whether this is a behavioral shift, perhaps in response to the novel Florida environment awaits more detailed behavioral observation.

While multivariate analysis did not show significant seasonal variation in diet composition, pairwise ANOSIM scores showed near significant p-values for combinations involving the brumation sample set. The p-values are likely a side effect of the small brumation sample size.

28 Conclusion

The Argentine black and white tegu is a well established invasive species in south

Florida with a dietary range that poses a serious threat to native wildlife. S. merianae can consume fruiting plants, insects, snails, crayfish, carrion, birds, small mammals, turtles, snakes, lizards, frogs and eggs from both reptiles and birds. This extremely broad dietary range makes it unlikely that S. merianae will be limited by food availability. The tegus affinity for eggs in ground level nests is of special concern in Florida where endangered species, such as the American crocodile (Crocodylus acutus), live and breed. The eastern edge of current S. merianae distribution borders the FPL’s Turkey Point mitigation area, which is populated with American crocodiles. Similar to alligators, Crocodiles create nests in higher areas adjacent to a water source, such as levees or berms. During the writing of this thesis, cameras placed on active nests of the American alligator (Alligator mississippiensis), Florida red-bellied cooter (Pseudemys nelson) and American crocodile in areas within the current tegu distribution showed footage of tegus repeatedly visiting and burrowing in and out of nests; the alligator and turtle nests were depredated by S. merianae (Mazzotti et. al. 2015). Ground-nesting bird populations, such as the federally endangered Cape Sable seaside sparrow (Ammodramus maritimus mirabilis) and the burrowing owl (Athene cunicularia), a species of special concern, are put at further risk by S. merianae. Historically, areas with invasive tegu populations have experienced severe negative impacts on the eggs of ground nesting birds and sea turtles (Homewood

1995). In coastal areas of south Florida, tegus could pose a significant threat to federally

29 endangered species of sea turtle such as loggerhead, green and leatherback (Caretta caretta, Chelonia mydas and Dermochelys coriacea). The state threatened gopher tortoise, Gopherus polyphemus, is another species which could be impacted; tortoise hatchlings and eggs could be prey items for S. merianae where their distributions overlap.

Most tegus with above average body condition were collected from disturbed/agricultural areas in the northwest portion of the established population. Better body condition could yield better reproductive success and increased offspring dispersal into adjacent, uninvaded lands (Cruz et. al. 1999).

In south Florida, S. merianae has progressed through three of the four stages of invasion: entry, establishment and spread. As shown by this study the final stage, impact, is likely to be huge. To date, efforts to contain and reduce the established S. merianae population have failed to draw significant, reoccurring funds. This miscalculation could be a grave error considering potential impacts and the difficulty of removing lizards once they have become established and spread into new locations. To reduce future spread, management efforts should be focused on areas containing tegus with the most reproductive potential, such as disturbed/agricultural areas, which could produce high numbers of offspring that subsequently spread into adjacent areas. Dedicated funds, staff and effort must be made a priority now to prevent the spread of S. merianae and reduce its impact on native Florida wildlife.

30 Figure 1: Map of study area for S. merianae collection.

Disturbed/agricultural Natural

Urban

Figure 2: Map of actual S. merianae collections, icon indicates capture habitat.

Table 1: Collection numbers displayed by variables for 169 tegu samples (2011 and 2012-2013 data.

Size Sex Habitat Body Condition

Class

Thin

Male

Adult

Obese

Urban

Robust

Female

Dist/Ag Dist/Ag

Natural

Juvenile Average Unknown

Emaciated N 90 79 83 82 4 64 71 34 26 33 51 36 23

Emergence 41 13 28 21 20 0 31 9 1 3 6 10 13 9 Breeding 91 50 41 44 47 0 26 38 27 22 18 25 16 10

Dispersal 32 24 8 16 12 4 5 23 4 1 8 15 5 3 Season

Collection Brumation 5 3 2 2 3 0 2 1 2 0 1 1 2 1

26 14 12 15 10 1 6 12 8 Emaciated 33 15 18 14 18 1 5 18 10 Thin 51 30 21 23 26 2 12 29 10 Average Body Body Robust 36 20 16 17 19 0 24 6 6 Condition Obese 23 11 12 14 9 0 17 6 0

Dist/Ag 64 32 32 40 24 0

Natural 71 44 27 27 40 4

Habitat 34 14 20 16 18 0 Urban 83 39 44 Female

Male 82 47 35 Sex 4 4 0 Unknown

Table 2: Frequency of occurrence of identified diet items from 169 tegu samples of overall food categories (2011 and 2012-2013 data). Eggs* category denotes eggs found in diets which could not have been part of bait.

Frequency of Occurrence (%) Size Class Sex Habitat Food Total Juvenile Adult Female Male Unknown Dist/Ag Natural Urban Category n = 169 n = 90 n = 79 n = 83 n = 82 n = 4 n = 64 n = 71 n = 34 Crustacea 5 7 4 7 4 0 0 13 0 Gastropoda 46 40 53 54 39 25 77 15 53 Insecta 76 78 75 81 72 75 81 85 50 Plantae 50 51 49 51 49 75 30 61 68 Vertebrates 37 29 46 33 42 25 30 39 44 Eggs* 10 11 9 8 12 0 13 10 6

34 Aves, egg 11 9 14 12 11 0 11 13 8

Leaf Litter 36 29 43 39 33 25 27 38 47

Collection Season Body Condition Food Emergence Breeding Dispersal Brumation Emaciated Thin Average Robust Obese Category n = 41 n = 91 n = 32 n = 5 n = 26 n = 33 n = 51 n = 36 n = 23 Crustacea 5 4 9 0 4 10 10 0 0 Gastropoda 66 41 38 40 31 30 35 69 74 Insecta 76 78 81 20 73 82 76 72 78 Plantae 39 51 63 60 62 61 53 36 39 Vertebrates 29 48 19 20 38 36 39 44 17 Eggs* 10 12 6 0 8 12 8 8 17 Aves, egg 11 0 6 17 8 12 14 8 13 Leaf Litter 39 40 19 40 50 33 37 36 17

Table 3: a – c, Analysis of similarity, ANOSIM, results. (a) by diet categories using 169 samples, (b) by plant families using 115 samples set and (c) by insect families using 115 sample set (a). Diet categories

Category Global R Significance level P-value Sex -0.002 56.40% 0.564 Size Class 0.005 22.60% 0.226 Habitat 0.201 0.10% 0.001 Collection Season 0.039 8.90% 0.089 Body Condition 0.013 18.60% 0.186

(b). Plant families

Category Global R Significance level P-value Sex -0.004 61.70% 0.617 Size Class 0.011 9.30% 0.0093 Habitat 0.095 0.10% 0.001 Collection Season -0.013 79.10% 0.791 Body Condition -0.014 88.40% 0.884

(c). Insect families

Category Global R Significance level P-value Sex -0.027 93.30% 0.993 Size Class 0.001 34.70% 0.347 Habitat 0.288 0.10% 0.001 Collection Season 0.048 11.40% 0.114 Body Condition 0.008 32.50% 0.325

Table 4: a-c. Pairwise tests for statistically significant ANOSIM scores. (a) by diet categories using 169 samples, (b) by plant families using 115 samples set and (c) by insect families using 115 sample set. Significance level of 0.1% is equivalent to a p- value of 0.001. (a). Diet categories R Actual Number ≥ Groups Significance Statistic Level (%) Permutations Observed Dist/Ag, Natural 0.226 0.1 999 0 Dist/Ag, Urban 0.211 0.1 999 0 Natural, Urban 0.16 0.1 999 0

(b). Plant families

R Actual Number ≥ Groups Significance Statistic Level (%) Permutations Observed Dist/Ag, Natural 0.128 0.1 999 0 Dist/Ag, Urban 0.021 19.4 999 193 Natural, Urban 0.095 0.1 999 0

(c). Insect families

R Actual Number ≥ Groups Significance Statistic Level (%) Permutations Observed Dist/Ag, Natural 0.379 0.1 999 0 Dist/Ag, Urban -0.019 70.5 999 704 Natural, Urban 0.283 0.1 999 0

Table 5. Similarity of percentages (SIMPER) results for diet comparison by capture habitat.

Group Disturbed/agricultural Average similarity: 59.66 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Insecta 0.81 29.31 1.28 49.12 49.12 Gastropoda 0.77 24.23 1.14 40.61 89.73 Plantae 0.30 3.00 0.30 5.03 94.77

Group Natural Average similarity: 54.61 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Insecta 0.85 33.41 1.32 61.17 61.17 Plantae 0.61 15.94 0.70 29.19 90.36

Group Urban Average similarity: 44.88 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Plantae 0.68 18.52 0.81 41.26 41.26 Gastropoda 0.53 10.5 0.57 23.40 64.66 Insecta 0.50 9.73 0.52 21.67 86.33 Vertebrata 0.44 6.10 0.47 13.59 99.91

Groups Disturbed/agricultural & Natural Average dissimilarity = 53.61 Dist/Ag Natural Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Gastropoda 0.77 0.15 16.33 1.31 30.46 30.46 Plantae 0.30 0.61 13.14 0.95 24.51 54.97 Vertebrata 0.28 0.34 9.27 0.82 17.29 72.26 Insecta 0.81 0.85 8.30 0.55 15.48 87.74 Eggs* 0.13 0.10 3.90 0.48 7.27 95.02

Groups Disturbed/agricultural & Urban Average dissimilarity = 54.44 Dist/Ag Urban Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Insecta 0.81 0.50 13.85 0.84 25.45 25.45 Plantae 0.30 0.68 13.79 0.98 25.33 50.78 Gastropoda 0.77 0.53 13.18 0.85 24.2 74.98 Vertebrata 0.28 0.44 10.29 0.88 18.91 93.89

Groups Natural & Urban Average dissimilarity = 56.15

Natural Urban Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Insecta 0.85 0.50 14.73 0.81 26.23 26.23 Plantae 0.61 0.68 13.14 0.78 23.41 49.63 Gastropoda 0.15 0.53 12.05 0.92 21.46 71.1 Vertebrata 0.34 0.44 10.9 0.89 19.42 90.51

Table 6. Similarity of percentages (SIMPER) results for plant families by capture habitat.

Group Disturbed/Agricultural Average similarity: 3.38 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Arecaceae 0.2 3.38 0.21 100 100

Group Natural Average similarity: 10.82 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Chrysobalanaceae 0.3 6.47 0.33 59.82 59.82 Anacardiaceae 0.2 2.4 0.2 22.19 82.01 Sapotaceae 0.11 0.85 0.11 7.87 89.88 Moraceae 0.12 0.77 0.12 7.16 97.04

Group Urban Average similarity: 7.11 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Arecaceae 0.29 5.24 0.32 73.75 73.75 Myrtaceae 0.15 0.98 0.15 13.77 87.52

Anacardiaceae 0.09 0.43 0.08 5.99 93.51

Groups Disturbed/Agricultural & Natural Average dissimilarity = 97.93 Dist/Ag Natural Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Chrysobalanaceae 0 0.3 21.93 0.69 22.39 22.39 Arecaceae 0.2 0.06 18.32 0.58 18.71 41.1 Sapotaceae 0.07 0.11 13.71 0.46 14 55.1 Anacardiaceae 0 0.2 13.12 0.51 13.4 68.5 Moraceae 0 0.12 7.44 0.38 7.6 76.1 Musaceae 0.07 0.02 6.46 0.31 6.6 82.7 Unknown AA 0.07 0 5.7 0.28 5.82 88.52 Zamiaceae 0.07 0 3.29 0.3 3.36 91.87

Groups Disturbed/Agricultural & Urban Average dissimilarity = 94.47 Dist/Ag Natural Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Arecaceae 0.2 0.29 28.95 0.86 30.64 30.64 Sapotaceae 0.07 0.03 8.66 0.34 9.17 39.81 Myrtaceae 0 0.15 7.84 0.47 8.3 48.11 Musaceae 0.07 0.03 7.34 0.34 7.76 55.88 Anacardiaceae 0 0.09 7.32 0.32 7.75 63.63 Melastomataceae 0 0.06 6.16 0.27 6.52 70.15 Unknown AA 0.07 0 5.84 0.28 6.18 76.33 Moraceae 0 0.06 4.75 0.26 5.03 81.36 Zamiaceae 0.07 0 3.35 0.3 3.55 84.91 Unknown L, R 0 0.06 3.34 0.28 3.54 88.45 Unknown V 0 0.03 3.08 0.19 3.26 91.71

Groups Natural & Urban Average dissimilarity = 96.35 Dist/Ag Natural Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.%

Arecaceae 0.06 0.29 17.22 0.67 17.87 17.87 Chrysobalanaceae 0.3 0 17.16 0.63 17.81 35.68 Anacardiaceae 0.2 0.09 14.57 0.55 15.12 50.8 Moraceae 0.12 0.06 9.01 0.43 9.35 60.15 Sapotaceae 0.11 0.03 8.8 0.38 9.13 69.28 Myrtaceae 0 0.15 6.23 0.44 6.47 75.75 Melastomataceae 0.02 0.06 5.2 0.28 5.39 81.14 Vitaceae 0.03 0.03 4.57 0.25 4.74 85.89 Unknown L, R 0 0.06 2.64 0.26 2.74 88.63 Unknown V 0 0.03 2.29 0.17 2.38 91.01

Table 7. Similarity of percentages (SIMPER) results for insect families by capture habitat. Group Disturbed/Agricultural Average similarity: 14.77 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Carabidae 0.4 12.63 0.4 85.5 85.5 Acrididae 0.2 1.35 0.17 9.12 94.63

Group Natural Average similarity: 38.93 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Romaleidae 0.7 38.07 0.92 97.78 97.78

Group Urban Average similarity: 5.51 Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% Carabidae 0.18 2.49 0.18 45.3 45.3 Romaleidae 0.18 2.49 0.18 45.3 90.6

Groups Disturbed/Agricultural & Natural Average dissimilarity = 91.20 Dist/Ag Natural Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Romaleidae 0.13 0.7 34.91 1.07 38.28 38.28 Carabidae 0.4 0.06 20.96 0.73 22.99 61.26 Acrididae 0.2 0.05 8.45 0.47 9.26 70.53 Dytiscidae 0.07 0.02 3.96 0.27 4.34 74.87 Scarabaeidae 0 0.09 3.54 0.29 3.88 78.75 Labiduridae 0.13 0 3.09 0.39 3.39 82.14 Blattidae 0.07 0.02 2.09 0.3 2.29 84.43 Curculionidae 0 0.05 1.88 0.19 2.06 86.48 Lepidoptera 0 0.05 1.73 0.19 1.89 88.37 Elateridae 0 0.05 1.51 0.21 1.65 90.03

Groups Disturbed/Agricultural & Urban Average dissimilarity = 91.12 Dist/Ag Urban Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Carabidae 0.4 0.18 33.93 0.84 37.23 37.23 Romaleidae 0.13 0.18 15.86 0.55 17.4 54.63 Acrididae 0.2 0.06 12.06 0.5 13.23 67.86 Dytiscidae 0.07 0 5.66 0.27 6.22 74.08 Scarabaeidae 0 0.09 4.62 0.28 5.07 79.15 Blattidae 0.07 0.03 4.06 0.3 4.46 83.61 Labiduridae 0.13 0 3.91 0.42 4.3 87.9 Belostomatidae 0 0.03 1.97 0.17 2.16 90.06

Groups Natural & Urban Average dissimilarity = 88.42 Natural Urban Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% Romaleidae 0.7 0.18 45.21 1.17 51.14 51.14 Carabidae 0.06 0.18 10.97 0.48 12.41 63.54 Scarabaeidae 0.09 0.09 7.92 0.41 8.95 72.49

Acrididae 0.05 0.06 4.44 0.29 5.02 77.51 Elateridae 0.05 0.03 3.43 0.27 3.88 81.39 Belostomatidae 0.03 0.03 2.98 0.24 3.37 84.77 Curculionidae 0.05 0 2.37 0.2 2.68 87.45 Lepidoptera 0.05 0 2.17 0.19 2.45 89.9 Blattidae 0.02 0.03 2.15 0.2 2.43 92.32

Table 8. Pearson’s Chi-Square statistic results for two-variable contingency tables. Shaded combinations were considered statistically significant ). V represents the degrees of freedom for each test, [v = (number of rows – 1) x (number of columns – 1)]

Variable I Variable II X²PEARSON V P-values Capture Habitat Sex 6.634 2 0.1 > p > 0.05 Capture Habitat Size Class 4.8 2 0.1 > p > 0.05 Capture Habitat Body Condition 43.47 8 0.001 Capture Habitat Collection Season 43.99 4 0.001 Collection Season Sex 0.6698 2 0.75 > p > 0.50 Collection Season Size Class 13.82 2 0.001 0.025 > p > 8 Collection Season Body Condition 19.95 0.01

Figure. 3 a & b. Bar graphs illustrating sex and size class of S. merianae collected throughout study, (a) by month and (b) by collection season.

18 16 14 12 10 8 6 4 2 Number of tegus capturedtegusof Number 0 Marc Jan Feb April May June July Aug Sept Oct Nov Dec h Male 1 2 8 4 7 10 3 0 0 0 0 0 Female 1 2 5 7 4 9 8 7 1 0 0 0 Juvenile 1 0 2 11 16 17 17 13 7 4 0 2

10 Number of tegus capturedtegusof Number 0 Emergence Breeding Dispersal Brumation Male 14 20 0 1 Female 14 21 8 1 Juvenile 13 50 24 3

Table 9. Frequency of Occurrence (FO) chart for 115 tegu sample set, family and species.

Food item Frequency of Occurrence (%) Collection Season Habitat Total Category Family Species Emer Breed Disp n = 115 n = n = n = Brum Dist/Ag Natural Urban 16 69 25 n = 5 n = 15 n = 66 n = 34 Insecta Romaleidae 47 25 51 56 20 13 70 18 Insecta Romaleidae Romalea guttata 47 25 51 56 20 13 70 18 Insecta Carabidae 14 19 16 8 0 40 6 18 Insecta Carabidae Pasimachus sp. 5 6 7 0 0 33 0 3 Insecta Scarabidae 8 6 9 8 0 0 9 9 Insecta Scarabidae Phyllophaga sp. 1 0 1 0 0 0 0 3 Insecta Acrididae 7 13 6 8 0 20 5 6

45 Insecta Elateridae 3 6 4 0 0 0 5 3

Insecta Curculionidae 3 0 6 0 0 0 6 0 Insecta Curculionidae Achonas blatchleyi 1 0 1 0 0 0 2 0 Insecta Belostomatidae 3 0 4 0 0 0 3 3 Insecta Belostomatidae Lethocerus sp. 3 0 4 0 0 0 3 3 Insecta Blattidae 3 13 1 0 0 7 2 3 Insecta Lepidoptera 3 6 3 0 0 0 5 0 Insecta Dytiscidae 2 6 0 4 0 7 2 0 Insecta Formicidae 2 0 3 0 0 0 3 0 Insecta Labiduridae 2 6 1 0 0 13 0 0 Insecta Labiduridae Labidura riparia 1 6 0 0 0 7 0 0 Insecta Myrmeleontidae 2 0 1 4 0 0 3 0 Insecta Blattellidae 1 0 1 0 0 0 2 0 Insecta Cerambycidae 1 0 0 4 0 0 2 0

Insecta Cydnidae 1 6 0 0 0 7 0 0 Insecta Histeridae 1 6 0 0 0 7 0 0 Insecta Orthoptera 1 0 0 4 0 0 0 3 Insecta Saturniidae 1 0 1 0 0 0 2 0 Insecta Stratiomyidae 1 6 0 0 0 7 0 0 Insecta Stratiomyidae Hermetia illucens 1 6 0 0 0 7 0 0 Insecta Tettigoniidae 1 0 1 0 0 0 2 0

Plantae Chrysobalanaceae 17 25 14 20 20 0 30 0 Chrysobalanaus 25 14 20 20 0 30 0 Plantae Chrysobalanaceae icaco 17 Plantae Anacardiaceae 14 6 16 12 20 0 20 9 Plantae Anacardiaceae Metopium toxiferum 13 0 16 12 20 0 20 6 Schinus

46 6 0 0 0 0 0 3 Plantae Anacardiaceae terebinthifolius 1

Plantae Arecaceae 18 25 16 20 20 20 6 41 Plantae Arecaceae Roystonea regia 4 0 7 0 0 7 0 12 Plantae Arecaceae Sabaleae palmetto 3 13 0 8 0 7 5 0 Plantae Arecaceae Dypsis lutescens 3 0 3 4 0 0 0 9 Plantae Arecaceae Palmae sp. 2 13 0 0 0 7 2 0 Syagrus 0 1 0 20 0 0 6 Plantae Arecaceae romanzoffiana 2 Plantae Arecaceae Phoenix roebelenii 1 0 0 4 0 0 0 3 Ptychosperma 0 1 0 0 0 0 3 Plantae Arecaceae elegans 1 Plantae Moraceae 9 6 9 12 0 0 12 6 Plantae Moraceae Ficus citrifolia 9 6 9 12 0 0 12 6 Plantae Sapotaceae 8 0 6 20 0 7 11 3 Plantae Sapotaceae Dipholis salicifolia 8 0 6 20 0 7 11 3

Plantae Myrtaceae 4 0 7 0 0 0 0 15 Plantae Myrtaceae Eugenia uniflora 4 0 7 0 0 0 0 15 Plantae Melastomataceae 3 0 3 4 0 0 2 6 Plantae Melastomataceae Tetrazygia bicolor 3 0 3 4 0 0 2 6 Plantae Musaceae 3 13 1 0 0 7 2 3 Plantae Musaceae Musa sp. 3 13 1 0 0 7 2 3 Plantae Vitaceae 3 0 1 8 0 0 3 3 Plantae Annonaceae 2 0 1 4 0 0 3 0 Plantae Annonaceae Annona glabra 2 0 1 4 0 0 3 0 Plantae Zamiaceae 1 0 1 0 0 7 0 0 Plantae Zamiaceae Zamia sp. 1 0 1 0 0 7 0 0 Plantae Unknown AA 1 6 0 0 0 7 0 0 Plantae Unknown L/R 2 0 1 4 0 0 0 6

47 Plantae Unknown N 1 0 1 0 0 0 0 3

Plantae Unknown T 1 0 0 4 0 0 2 0 Plantae Unknown V 1 0 0 0 20 0 0 3 Plantae Unknown Z 1 0 1 0 0 0 0 3 0 0 0 0 0 0 0 0 Mammals 19 25 20 16 0 33 12 26 Cricetidae 10 13 10 12 0 13 11 9 Cricetidae Sigmodon hispidus 9 6 10 8 0 13 9 6 Muriadae Rattus rattus 2 13 0 0 0 13 0 0 Didelphidae Didelphis virginia 1 0 1 0 0 0 0 3 Felidae Felis catus 1 0 1 0 0 0 0 3 Reptiles 6 0 9 4 0 0 9 3 Turtles 3 0 4 4 0 0 5 3 Snakes 2 0 3 0 0 0 3 0 Lizards 1 0 1 0 0 0 2 0

Amphibians 4 6 4 4 0 7 3 6 Frogs 4 6 4 4 0 7 3 6 Birds 2 0 3 0 0 0 0 6 Unk Vert 3 0 4 4 0 0 6 0 0 0 0 0 0 0 0 0 Crustacea Camabaridae Procambarus sp. 7 13 6 8 0 0 12 0 Crustacea Unk 1 0 0 4 0 0 2 0

Eggs 9 0 13 4 0 7 11 6 Leaf Litter 44 56 49 24 40 60 39 47 Bait 12 31 10 8 0 13 14 9

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