Population Status, Distribution, and Home Range of the Alligator Snapping Turtle (Macrochelys temminckii) in the Suwanne...

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Title:
Population Status, Distribution, and Home Range of the Alligator Snapping Turtle (Macrochelys temminckii) in the Suwannee River, Florida
Physical Description:
1 online resource (72 p.)
Language:
english
Creator:
Thomas, Travis Michael
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
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Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Wildlife Ecology and Conservation
Committee Chair:
ROSS,JAMES PERRAN
Committee Co-Chair:
FLETCHER,ROBERT JEFFREY,JR
Committee Members:
JOHNSON,STEVEN ALBERT
PINE,WILLIAM E,III

Subjects

Subjects / Keywords:
chelonian -- ecology -- geomorphology -- macrochelys -- population -- reach -- river -- suwannee -- telemetry -- turtle -- ultrasonic
Wildlife Ecology and Conservation -- Dissertations, Academic -- UF
Genre:
Wildlife Ecology and Conservation thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
The alligator snapping turtle (Macrochelys temminckii) has experienced population declines throughout much of its range because of extensive harvest. Little is known about the genetically and morphologically distinct population of Macrochelys in the Suwannee River. In Georgia, efforts failed to capture Macrochelys in the Suwannee River, creating concern about this species status. To determine the status of Macrochelys in the Suwannee River, a mark-recapture and telemetry study was conducted between 2011 and 2013. In total, 132 individual Macrochelys were captured (21.2% juveniles,17.4% females, and 61.4% males). Sex ratio was male-skewed (3.5:1) and 41% of males weighed =45kg. Relative abundance and density estimates revealed an uneven distribution of turtles throughout the river, with more productive river sections maintaining higher population densities and larger turtles. Mean linear home ranges were 1,896 m ± 252 m for males and 1,615 m ± 301 m for females. Telemetry data revealed habitat use patterns not previously reported for Macrochelys,with individuals making frequent overland movements between the floodplain and river channel. Side-scan sonar maps paired with turtle locations indicated coarse woody debris, undercut banks and large rocks are important habitat during low water levels. Bush hook surveys and radiographs revealed a positive correlation between bush hook abundance and number of ingested hooks. Macrochelys in the Suwannee are more numerous than previously thought; however, several threats exist including fish hook ingestion, boat propeller damage, and the removal of woody debris.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
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Description based on online resource; title from PDF title page.
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This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Travis Michael Thomas.
Thesis:
Thesis (M.S.)--University of Florida, 2013.
Local:
Adviser: ROSS,JAMES PERRAN.
Local:
Co-adviser: FLETCHER,ROBERT JEFFREY,JR.

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UFRGP
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Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0046412:00001


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1 POPULATION STATUS, DISTRIBUTION, AND HOME RANGE OF THE ALLIGATOR SNAPPING TURTLE ( MACROCHELYS TEMMINCKII ) IN THE SUWANNEE RIVER, FLORIDA BY TRAVIS M. THOMAS A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FL ORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2013

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2 2013 Travis M. Thomas

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3 ACKNOWLEDGMENTS I would lik e to thank my committee members: Perran Ross, Bill Pine, Rob Fle tcher, and Steve Johnson for their support Brittany Burtner Adam Cas avant La uren Cashman, Madeleine Cascarano Kevin Enge, Mich ael Granatosky, Jerry Johnston, Anthony Lau, Paul Moler Eric Suarez, Mike Ruccolo Bi ll Turner and Woodward assisted in the f ield. Natalie Lamneck provided radiographs. Katie Sieving helped with study design. Savanna Barry and Erin Leone provided statistical consultation. Ryan Butryn and Anna Farmer provided GIS assistance Adam Kaeser assisted with side scan sonar mapping. Came ron Carter and Hugo Gianfrancesco helped modify and repair equipment. Tim Donovan took phot os and a video of the project. Andrew Gude, Larry Woodward, Amy Thompson, Bobby Toothaker Benjamin Gill, Kevin Lamar, Joe Roman, and Brad Stanley facilitated resear ch. Kenneth Krysko vouchered photo graph s in the Flor ida Museum of Natural History. May Lehmensiek, Derek Piotrowicz, Rick Stout, a nd Ben Williams supplied bait.

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4 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 3 LIST OF TABLES ................................ ................................ ................................ ............ 6 LIST OF FIGURES ................................ ................................ ................................ .......... 7 LIST OF ABBREVIATIONS ................................ ................................ ............................. 9 ABSTRACT ................................ ................................ ................................ ................... 10 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 12 The Alligator Snapping Turtle ................................ ................................ ................. 12 Natural History ................................ ................................ ................................ .. 12 Distributional Gap ................................ ................................ ............................. 15 Conservation Status ................................ ................................ ......................... 16 Status of Macrochelys in the Suwannee River ................................ ................. 17 Geomorphic Riverine Processes ................................ ................................ ............ 18 Objectives ................................ ................................ ................................ ............... 20 Turtle Relative Abundance and Density ................................ ........................... 20 Turtle Population Structure ................................ ................................ ............... 20 Turtle Home Range ................................ ................................ .......................... 2 0 Prevalence of Ingested Fis h Hooks ................................ ................................ .. 21 2 METHODS ................................ ................................ ................................ .............. 24 Study Site ................................ ................................ ................................ ............... 24 Sampling ................................ ................................ ................................ ................. 25 Ultrasonic Telemetry ................................ ................................ ............................... 28 Habitat Mapping ................................ ................................ ................................ ...... 28 Bush Hook Surveys ................................ ................................ ................................ 29 Data Analyses ................................ ................................ ................................ ......... 29 Turtle Relative Abundance and Density ................................ ........................... 29 Turtle Population Structure ................................ ................................ ............... 30 Turtle Home Range ................................ ................................ .......................... 30 Prevalence of Ingested Fishhooks ................................ ................................ ... 31 3 RESULTS ................................ ................................ ................................ ............... 40 Turtle Relative Abundance and Density ................................ ................................ .. 40 Turtle Population Structure ................................ ................................ ..................... 40 Turtle Home Range ................................ ................................ ................................ 41

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5 Prevalence of Ingested Fish Hooks ................................ ................................ ........ 42 4 DISCUSSION / CONCLUSION ................................ ................................ ............... 54 Hypoth eses Revisited ................................ ................................ ............................. 54 Discussion ................................ ................................ ................................ .............. 55 Conclusions ................................ ................................ ................................ ............ 64 REFERENCES ................................ ................................ ................................ .............. 67 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 72

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6 LIST OF TABLES Table page 3 1 Captures, trap nights, and mean Capture Per Unit Effort (CPUE) by reach and site. ................................ ................................ ................................ .............. 44 3 2 Sex ratios for the entire sample and by reach. No adults were captured in Reach 6. ................................ ................................ ................................ ............. 44 3 3 M orphological measurements and masses of 132 Macrochelys captured in the Suwannee River. ................................ ................................ .......................... 45 3 4 Mean linear home range of Macrochelys with standard error for sex and reach. ................................ ................................ ................................ ................. 45

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7 LIST OF FIGURES Figure page 1 1 Genetic structure of Macrochelys showing both nuclear and mitochondrial genetic variation among drainages. Used with permission from th e authors (Echelle et al., 2010). ................................ ................................ .......................... 22 1 2 The d istributional gap within the range of Macrochelys The distributional gap is made up of small coastal rivers including: the St. Marks, Aucilla, Eco fina, Fenhollaway, and Steinhatchee Rivers in Florida. ................................ .............. 22 1 3 Photograph of the open mouth of an adult Macrochelys (top to bottom) showing the nostrils, upper jaw, modified wormlike tongue, and lower jaw.. ...... 23 2 1 Map of the Suwannee River. ................................ ................................ .............. 32 2 2 Map of the Suwannee River showing 6 ecological reaches. ............................... 32 2 3 Photographs of Reach 1 showing high limestone banks and a narrow river channel.. ................................ ................................ ................................ ............. 33 2 4 Photographs of Reach 2 showing an increase in channel width and a reduction of limestone banks. ................................ ................................ ............. 33 2 5 Photographs of Reach 3 showing a wider channel and spring water flowing into the channel. Limestone banks are less frequent.. ................................ ........ 34 2 6 Photographs of Reach 4 showing wide channel with major spring input. Photos courtesy of Travis Thomas and Kevin Enge. ................................ .......... 34 2 7 Photographs of Reach 5 sh owing very wide channel, emergent vegetation, and expansive flood plain.. ................................ ................................ ................. 35 2 8 Photographs of Reach 6 (estuary) showing very wide channel, tidal salt marsh, and floodplain creek. ................................ ................................ ............... 35 2 9 Map of the Suwannee River showing 2 randomly selected study sites within each reach. ................................ ................................ ................................ ......... 36 2 10 Photographs showing traps set during this stu dy.. ................................ ............. 37 2 11 Photograph showing modified trapping technique utilized within the estuary.. ... 37 2 12 Photographs of morphologic measure ments being taken.. ................................ 38 2 13 Photographs showing mass of adult (above) and immature (below) turtles being taken.. ................................ ................................ ................................ ....... 38

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8 2 14 Photograph showing the insertion of a Passive Integrated Transponder (PIT) tag into the ventral tail of a Macrochelys captured in the Suwannee River.. ....... 39 2 15 Photograph showing the attachment of an ultras onic transmitter to the posterior carapace of a Macrochelys captured in the Suwannee River . ............ 39 3 1 Catch Per Unit Effort ( CPUE) by reach with standard error. Letters indicate significance. Reac h 1 and 5 had relatively lower estimated abundance than Reaches 2, 3, and 4. ................................ ................................ .......................... 46 3 2 Estimation of adult turtle density by reach from a closed population model with standard error. Estimate is fo r 10km of river in each reach. ........................ 46 3 3 Size distribution for Macrochelys captured in the Suwannee River from 2011 2013. ................................ ................................ ................................ ......... 47 3 4 Size d istribution for Macrochelys captured in the Suwannee River by reach from 2011 2013. ................................ ................................ ................................ 48 3 5 Frequencies of captured Macrochelys ................... 49 3 6 Measurements of A) carapace length, B) mass, C) carapace width, D) plastron length, and E) head width of adult male and female Macrochelys using ANOVA with re ach as a covariate. Letters indicate significance. .............. 50 3 7 Map showing 4 turtles located within the floodplain during high water levels in Reach 1. Different colors represent different turtles. ................................ .......... 51 3 8 Sonar map image showing turtle #115 frequently located around a cluster of submerged woody debris. ................................ ................................ .................. 51 3 9 Map showing turtle # 31 frequently located in a small spring and spring run. ...... 52 3 10 Radiograph showing 3 fishing hooks in the upper gastrointestinal tract of a Macrochelys from the Branford site (Reach 3). ................................ .................. 52 3 11 Plot showing the relationship between number of bush hooks present and ingested fish hooks found in turtles in Reach 1 (circle) and Reach 3 (triangle). . ................................ ................................ ................................ .......... 53 4 1 Photographs of damage ascertained from a boat propeller on 2 Macrochelys in the Suwannee River.. ................................ ................................ ..................... 66

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9 LIST OF ABBREVIATIONS A NOVA Analysis of variance C ITES Convention on International Trade i n Endangered S pecies C L Midline carapace length C PUE Capture per unit e ffort C W C arapace width D NA D eoxyribonucleic acid E SU E volutionarily significant units Fwc Florida Fish and Wildlife Conservation C ommission F LMNH Florida Museum of Natural H istory G PS Global positioning system H W Head width M TDNA Mitochondrial d eoxyribonucleic acid N DNA Nuclear d eoxyribonucleic acid P CL Precloacal tail length P IT Passive integrated transponder P L Plastron length P VC Polyvinyl chloride R CC River continuum concept S D I Sexual dimorphism index S RWMD Suwannee River Water M anag ement D istrict T L Tail length U SFWS United States Fish and Wildlife Service

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10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science POPULATION STATUS DISTR I BUTION, AND HOME RANGE OF THE ALLIGATOR SNAPPING TURTLE ( MAC R OCHELYS T EMMINCKII ) IN THE SUWANNEE RIVER, FLORIDA By Travis M. Thomas December 2013 Chair: James Perran Ross Major: Wildlife Ecology and Conservation The alligator snapping turtle ( Macrochelys temminckii ) has experienced population declines throughout much of its range because of extensive harvest L ittle is known about the genetically and morphologically distin ct population of Macrochelys in the Suwannee River In Georgia, efforts failed to capture Macrochelys in the Suwannee River, creating concern about this species status. To determine the status of Macrochelys in the Suwannee River, a mark r ecapture and tele metry study was conducted between 2011 and 2013. In total, 1 32 individual Macrochelys were captured ( 21.2% juveniles 17.4% females, and 61.4% males ) Sex ratio was male skewed (3.5:1) and 41% of males weighed 45kg. Relative abundance and density estimates revealed an uneven distribution of turtles throughout the river with more productive r iver sections maintain ing higher population densit ies and larger turtles. Mean linear home range s were 1,896 m 252 m fo r males and 1,615 m 301 m for females T elemetry data revealed habitat use patterns not previously reported for Macrochelys with individuals ma king overland movement s between the floodplain and river channel Side scan sonar maps paired with turtle loca tions indicated c oarse woody debris undercut

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11 banks and large rock s are important habitat during low water levels Bush hook surveys and radiographs revealed a positive correlation between bush hook abundance and number of ingested hooks Macrochelys in th e Suwannee are more numerous than previousl y thought; however, s everal threats exist including fish hook ingestion, boat propeller damage, and the removal of woody debris

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12 CHAPTER 1 INTRODUCTION The Alligator Snapping Turtl e Natural History The alligator snapping tu rtle ( Macrochelys temminckii ) is the largest fre shwater turtle in the western hemisphere (Ernst et al., 1994; Pritchard 2006). Macrochelys possesses a carapace that is heavily serrated posteriorly with three longitudinal rows of prominent keels Pritchard (2006) discussed historical size of Macrochelys but many accounts are unconfirmed and anecdotal in nature. Pritchard (2006) mentioned a record sized ( 404 lb ) specimen reported by Hall and Smith (1947); however, after corresponden ce with one of the author s, he suggested that this record should not be accepted. One well known trapper, Al Redmond, a 142 kg (313 lb) Macrochelys in from the Flint River system in Georgia but this record is also questionable The largest Macrochelys on record with a verifiable mass was an individual that was captured in Texas and then kept in captivity in the Metropolitan Toronto Zoo In 1984, this turtle weighed 104.3 kg ( 230 lb s ) While males potential ly reach large size s, Macrochelys exhibit sexual dimorphism and f emales weigh much less (Ernst et al., 1994; Pritchard 2006). Alligator snapping turtles are restricted to river systems and associated wetlands that drain into the northern Gulf of Mexico from Florida to Texas ( Pritchard 2006 ) Macrochelys is characteriz ed as a secretive turtle often difficult to study in the wild (Zappalorti, 1971; Elsey, 2006) Despite this, a considerable amount of information is available on this species ( Dolbie, 1971; Pritchard, 1979, 2006 ; Ernst et al., 1994; Roman et al., 1999; El sey 2006; Riedle, 2006 ), but much remains

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13 unknown about its basic ecology and conservation status ( Pritchard 2006; Roman et al., 1999) Macrochelys possesses a large head and powerful jaws used for crushing prey items (Pritchard, 2006) For example, a 5 4.5 kg (120 lb) individual recorded a bite force of nearly 4448 N (1000 lbs) (T.M. Thomas, unpublished data). M ost knowledge concerning food habits of M acrochelys is derived from ane cdotal reports ( see Pritchard 2006) and a few studies conducted in the we stern part of their range (see Sloan et al. 1996 ; Harrel and Stringer 1997 ; Elsey 2006) Dobie (1971) noted an unusual quantity of acorns and palmetto berries in turtle s from Louisiana M acrochelys have been reported feeding on fish, mollusk s crustacea ns, small alligators ( Alligator mississippiensis ) snake s turtle s insect s bird s mammals aquatic salamanders, and plant material (Allen and Neill 1950; Dobie 1971; Sloan et al. 1996; Harrel and Stringer 1997; Elsey 2006 ). This suggest s that adult Macrochelys are opportunistic scavengers (Elsey, 2006) but juveniles may be m a modifi ed tongue that resembles a worm) for prey capture (Spindel et al., 1987; Pritchard 2006). The diet of Macrochelys in Florida has not been st udied Macrochelys are characterized as relatively sedentary (Ernst et al., 1994) ; but Pritchard (2006) proposed that some individuals may constantly move upstream during their lifetime. T elemetry studies in Missouri, Kansas, Oklahoma, and Louisiana showe d extensive turtle move ments throughout available aquatic habitat with rest ing or core sites generally associated with greater habitat structure and denser canopy cover (Sloan and Taylor, 1987; Shipman, 1993; Shipman et al., 1995 ; Riedle et al., 2006) Mo st of these studies took place in the western part of M range and were

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14 conducted in lakes impoundments, and small streams Thus very little information exists on turtle movements in la rge, free flowing river systems or in the eastern part of th eir distribution Dobie (1971) dissected 231 Macrochelys that were harvested for meat by a com mercial fish house in Louisiana and estimated that sexual maturity is reached in 11 13 years H owever, other studies have shown sexual maturity requires 15 21 ye ars (Sloan et al. 1996, Tucker and Sloan 1997, Reed et al. 2002, Woolsey 2005) Information on courtship is absent in this species (Pritchard, 2006) but c opulation has been witnessed by Allen and Neil ( 1950 ) According to Allen and Neil (1950), copulatio n last ed fro m 5 25 minutes. Nesting typically occurs in the months of April, May, and June (Dobie, 1971 Ewert, 1994 ) Nests are typically constructed in sandy soil within 20 m of the water, but some nests may be as far away as 200 m (Ewert, 1994 ). Macroch elys like many other reptiles, has temperature dependent sex determination It is believed that higher nesting temperatures produce more female turtles (Ewert, 1994). Typically Macrochelys lay one clutch a year, but some individuals may lay every other y ear (Dobie, 1971). Clutch sizes in Louisiana had a mean of 24.5 (range 16 52 ). In Florida, Ewert (1994) found c lutch sizes averaged approximately 36 eggs (range 17 52). In Florida, most egg 1994 ). Molecular studies conducted on Macrochelys using both mitochondrial (mtDNA) and nuclear (nDNA) revealed considerable genetic variation across its range (Roman et al., 1999, Echelle et a l., 2010 ; Figure 1 1 ). Roman et al. (1999) used mtDNA to propose three distinct genetic assemblages (western, central, and Suwannee), with turtles from

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15 the Suwannee River assemblage being the most distinct and showing a deep separation from other drainages Nuclear (nDNA) results suggests the presence of six rivers inhabited by Macrochelys : (1) Trinity, Neches, and Mississippi, (2) Pascagoula, (3) Mobile and Perdido, (4) Pensacola, (5) Choctawhatchee, Econfina Apalachicola, and Ochlockonee, and (6) Suwannee River drainages, and this analysis also identified the Suwannee River assemblage as most genetically distinct (Echelle et al., 2010). Recent research suggests that morphological differences corresponding to previous molecular findings, also exist among Macrochelys populations, and currently two new species of Macrochelys have been proposed based on these differences (Thomas et al., in review ) Distributional Gap Although this species is restricted to rive r systems that drain into the Gulf of Mexico from Florida to Texas, there appears to be a distributional gap in the range of this species There are no confirmed records from several small coastal rivers including the Steinhatchee, Fenholloway, Econfina, A ucilla, Wacissa, Saint Marks, and Wakulla rivers ( Ewert et al. 2006 ; Figure 1 2 ) Pritchard (2006) notes there are two undocumented sightings from the Wacissa River Additionally, the Florida Natural Areas Inventory records include a live specimen observed in the Wakulla River, a dead verify these anecdotal reports. To date, no official voucher ed specimens exist between the Suwannee and Ochlockonee River systems and this apparent distributional gap and geographic isolation have likely resulted in Macochelys in the Suwannee River

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16 drainage being the most genetically and morphologically distinct ( Thomas et al., in review ) Conservation Status Due to extensive commercial and non commercial harvest Macrochelys populations have experienced significant declines across much of their geographic range ( Dobie, 1971 ; Ewert et al., 2006; Pritchard, 2006) Campbell Soup Company was an alleged buyer of Macrochelys canned snapper soup ( Pritchard 2006). O fficials from the Florida Game and Freshwater Fish Commission reported that turtles were caught in great numbers from t he Apalachicola and Ochlock o nee Rivers and presumably trucked to New Orleans to be sold for soup (Pritchard, 2006) Al Redmond, a commercial fisherman reportedly harvested 4000 5000 adult Macrochelys from the Flint River system from 1971 1983 (Johnson, 19 89). numbers in Mississippi Louisiana Georgia, Alabama, and Texas (Pritchard, 2006). In 1972, Florida was the first state to limit take on Macrochelys by passing regulati on that limited possession to one turtle per person While this regulation still allowed for minimal non commercial harvest, it effective ly banned any and all commercial harvest in Florida In 1983, Peter Pritchard petitioned the United States Fish and W ildlife Service (USFWS) to list the species as Threatened under the U.S. Endangered Species Act; however, according USFWS, it did not meet the requirement s for listing Today, t he management of this species continues largely at the state level and Macroch elys is afforded some protection in every state in which it occurs (Pritchard, 2006). I n 2006, responding to reports of extensive export to Asian food markets, Macrochelys was listed in Appendix III of the Convention on International Trade in Endangered Sp ecies

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17 (CITES), which now requires federal oversight and export permits that monitor and limit international trade In addition to pop ulation declines due to harvest human altered landscapes and the modification of rivers and subsequent loss of habitat ar e also a concern for the viability of these populations ( Ewert et al., 2006). Abandoned trotlines (a long line with shorter lines attached at intervals that possess hooks that are usually baited) have been reported as a major problem in Georgia, and have been known to unintentionally capture and drown Macrochelys ( Pritchard 2006). Ingested fishing tackle is a concern because fish hooks can perforate the digestive tract and eventually cause death in turtles. Several turtles in the Santa Fe River, a tributar y of the Suwannee River, were found to have ingested fish hooks (Thomas unpublished data). Bush hooks set for fish (a single baited fish hook line, and and sinker attached to a branch overhanging the river) are common in this system and are usually set in the evening and checked the next day. Because of this, Macrochelys are more likely to come in contact with these baited hooks due to the ir nocturnal activity. These and other a nthropogenic threats that lead to increased mortality rates represent a major co ncern to the long term viability of Macrochelys due to long generation times and low reproductive rates (Tucker and Sloan 1997, Reed et al. 2002); therefore, Macrochelys may require a lon g period of time for populations to recover. Status of Macrochelys i n the Suwannee River The Suw annee River is the southeastern most limit of the range of Macrochelys Although Moler (1996 ) reported the presence of Macrochelys in t he Suwannee and Santa Fe Rivers during a statewide survey Pritchard (2006), citing mainly park

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18 naturalist s in Florida and Georgia concluded that Macrochelys are scarce within the Suwannee River and the Okefenokee Swamp. He suggested Macrochelys was more numerous in (Pritchard, 2006). Surveys conducted in Georgia (Jensen and Birkhead, 2003) failed to capture Macrochelys in the upper Suwannee despite intensive sampling and t he authors suggested low pH and its effect on prey items along with impacts associated with commercial harvest were possible explanations Alternatively, Jensen and Birkhead (2003) suggested that Macrochelys may not be common throughout the eastern most part of their range. Recent resea rch has suggested that Macrochelys in the Suwannee are unique from other populations which make the evaluation of its status important. As a pr oposed new taxon limited to single river drainage, if Macrochelys is as scarce as previously suggested it may be of significant conservation concern and require special management and protection. Therefore, establishing its true status ( including distribution, density, population structure, home range, habitat use, and threats ) is critical for the future management of this species. These are the questions I addressed in this thesis. Geomorphic Riverine Processes Rivers, in their natural state, are linearly connected and highly dynamic ecosystems (Decamps, 2011). Typically rivers exhibit changes in a multitude of ch aracteristics ( i. e. width, depth, velocity, flow volume and temperature) from the headwaters to the mouth (Vannote et al., 1980) The changes in patterns and processes within lotic systems are oriented downstream (Ward, 1989; Townsend, 1996) The constan t change along a river can impede the detection of biological patterns crucial to

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19 the management of imperiled species (Duncan, 2009) The River Continuum Concept (RCC) is one construct to help explain how patterns and processes change longitudinally in riv ers and how they potentially affect biotic communities. Rivers possess a continuous gradient of physical conditions that results in a continuum of biotic adjustment as water travels downstream from the headwaters to the lower reaches (Vannote, 1980). The R CC is based in part on the premise that energy input, organic matter transport, storage, and use by macroinvertebrate feeding groups (shredders, collectors, grazers, and predators) may be regulated largely by fluvial geomorphic processes such that resource s tend to increase downstream (Vannote, 1980) Much of our current knowledge of stream and river ecology has come from studies on fishes Past studies have revealed that changes in riverine habitat can potentially affect biological communities of aquatic insects (Roy et al., 2003), and fish communities (Sutherland et al., 2002; Walters et al., 2003). However, little is known of how changes in rivers potentially influence turtle communities. The Suwannee River is the second largest river by drainage in Flo rida and serves as a key geological and ecological break between the peninsula and panhandle regions During its course through North Florida, the Suwannee River experiences geologic and physiogeologic longitudinal changes in water chemistry (Ceryak et al. 1983) These changes in water chemistry led the Suwannee River Water Management District (SRWMD) to divide the river into 6 distinct ecological reaches ( Hornsby et al., 2000). These ecological reaches within the Suwannee can be thought as sections of riv er that share similar physical, chemical, and ecolo gical conditions and presumably, different resources for Macrochelys.

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20 Objectives For this study, my goal was to answer questions regarding the status of Macrochelys within the Suwannee River Also I inve stigate d the effect of geomorphic r iverine processes embodied by the six distinct ecological reaches on Macrochelys relative abundance, density, population size structure, and home range Lastly, I investigated the prevalence of ingested fish hooks in Ma crochelys within the Suwannee River. Turtle Relative A bundance and Density Question : Do es ecological reach affect population abundance of the alligator snapping turtle within the Suwannee River? Hypothesis : Based on the RCC, I predict alligato r snapping turtle abundance will increase in the middle and lower reaches relative to upper reaches Turtle Population Structure Question: Do es ecological reach affect population structure (sex ratio and size distribution) of the alligato r snapping turtle within the Suwannee River? Hypothesis: Based on the RCC, I predict that alligator snapping turtle s will exhibit no change in sex ratio among reaches and smaller size class es in the upper reach relative to middle and lower reaches Turtle Home Range Question: Does linear home range size differ in two distinct river reaches (Reach 1 and Reach 3)? Hypothesis: Due to the increase in river productivity (predicted by both the RCC and observed by the SRWMD ( Hornsby et al., 2000 ), I predict alligator snapping turtles in Reach 3 will exhibit smaller home ranges than turtles in Reach 1

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21 Prevalence of Ingested F ish H ooks Question: Is the impact and threat to turtles from non commercial fisheries (e.g. bush hooks) different i n different reaches. Hypothesis: I predict that the prevalence of ingested fish hooks will be higher in the site with a higher number of bush hooks.

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22 Figure 1 1 Genetic structure of Macrochelys showing both nuclear and mitochondrial genetic variation among drainages Used with permission from the author s ( Echelle et al., 2010 ). Figure 1 2 Map of d istributional gap within the range of Macrochelys The distributional gap is m ade up of small coastal rivers including: the St. Marks, Aucilla, Ecofi na, Fenho l laway, and Steinhatchee Rivers

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23 Figure 1 3 Photograph of the open mouth of an adult Macrochelys (top to bottom) showing the nostrils, upper jaw, modified wormlike tongue and lower jaw Photo courtesy of Travis Thomas.

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24 CHAPTER 2 M ETH ODS Study Site The Suwannee River is a major river system of Florida and south ern Georgia that flows 378 km (235 miles) from the Okefeno kee Swamp in southeastern Georgia to the Gulf of Mexico in Florida (Figure 2 1). The Suwannee River experiences longitud inal changes in water chemistry from the headwaters to the mouth (Ceryak et al., 1983) that led the Suwannee River Water Management District (SRWMD) to divide the river into 6 distinct ecological reaches: Upper River Blackwater, Cody Scarp Transitional, Mi ddle River Calcareous, Lower River Calcareous, Tidal Riverine, and Estuarine (Hornsby et al. 2000; Figure 2 2). These reaches are characterized by their chemical and ecological features, including differing levels of biological productivity. Reach 1 (Upp er River Blackwater Reach; Figure 2 3) is characterized by deeply incised limestone banks with a mostly shallow < 1m channel The width of the rive r varies from ca. 30 49 m with some shoals exposed along the river The river in R each 1 is a typical low nut rient acidic blackwater stream. R each 2 (Cody Scarp Transitional Reach ; Figure 2 4 ) has moderately incised limestone banks; however the channel widens to ca. 40 80 m in width The channel is still somewhat shallow with depths averaging ca. 1 2 m with num erous sandy and rocky shoals along the river Reach 2 experiences an increase in nutrients and biological productivity and t his reach includes the confluences of two tributaries: the Alapaha and the Withlacoochee Rivers The Cody Scarp is a steep face tha t constitutes the most prominent topographic feature in the state; it divides the Northern Highlands and Gulf

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25 Coastal L owlands physiographic regions. The Suwannee River is the only major stream that does not go underground while crossing the Cody Scarp (Ra ulston et al. 1998). Reach 3 (Middle River Calcareous Reach ; Figure 2 5 ) has higher flows and a larger floodplain The river is significantly larger with deep pools and a wider channel of ca. 80 100 m or more Some limestone out crops are still visible. Ma jor springs are fairly common within this reach This reach crosses the Central Florida Ridges and Uplands subregion and the Gulf Coast Flatwoods subregion. Reach 4 (Lower River Calcareous Reach ; Figure 2 6 ) begins at the Santa Fe River confluence and lies entirely within the Gulf Coast Flatw oods subregion. The river (Fig. 8). Shoals are absent, and major springs are found throughout the floodplain. Reach 5 (Tidal River Reach ; Figure 2 7 ) begins at the town of Fan ning Springs and also lies entirely within the G ulf Coast Flatwoods subregion. The river channel is up of substrates such as limeston e, coarse sand, and sandy mud. Two major springs, Fanning and Manatee, are present. Tidal variation is evident, particularly during low flow conditions, and normally extends ca. 43 km upstream from the mouth. Reach 6 (Estuary; Figure 2 8) has va riable salinity and extends ca. 16 km upstream from the mouth. About 10 km before it reaches the Gulf, the Suwannee branches into West Pass and East Pass, which are up to 6 m deep and flow through a broad delta area. Sampling The Suwannee River was divided into 5 km sections from White Springs to the Gulf of Mexico. Two sections in each of the six d istinct ecological reaches were

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26 randomly selected as survey sites ( Figure 2 9 ) Alligator snapping turtles were trapped using custom single funnel 4 ft (122 cm) diameter fiberglass hoop net traps with #36 twine a nd Typically 12 traps were set at each site; however on a few occasions, inclement weather and water level extremes prevented the full complement of traps from being set. Traps were baited with fresh cut or fresh ground fish obtained from local fish markets and our trap by catch, and consisted of a varie ty of different species such as Florida gar ( Lepisosteus platyrhincus ) red snapper ( Lutjanus campechanus ) American gizzard shad ( Dorosoma cepedianum ) bowfin ( Amia calva ), s triped mullet ( Mugil cephalus ) grass carp ( Ctenopharyngodon idella ) gulf flounder ( Paralichthy albigutta ) and triggerfish ( Balistes sp ) In order to effectively sample for population data, t raps were dispersed throughout each site Traps were not always set upstream from fallen trees, log jams, and undercut banks as suggested by Moler, 1996 ; Jensen and Birkhead, 2004 Instead, t raps were set from overhanging branches roots, or rocks in depths of 0.9 2.7m ( 2 6 ft ) in moderate current and with the funnel opening facing downstream The two front hoops were always sitting on the bottom and traps were parallel to the bank with current moving directly through the throat of the trap (Figure 2 10 ) In the estuary, modified traps were made by attaching two traps together at the back with cable ties so that funnel openings would be facing both upstream and downstream directions ( Figure 2 11 ) This allowed traps to function in shifting currents Due to the lack of hanging branches in the estuary, we hammered 3 inch polyvinyl chloride ( PVC ) pipe into the substrate to which traps were attached. Traps were set in the afternoon and checked the next morning.

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27 All captured Macrochelys were measured for straight mid line carapace length (CL) carapace width ( CW), maximum h ead width (HW) plastron length (PL) precloacal tail length (PCL) and postcloacal tail length (TL) ( Figure 2 12 ) Straight line measurements ( CL, CW, HW, PL) were taken to the nearest 1mm with 95 cm Haglof aluminum tree calipers The remaining measureme nts (PCL, TL) were taken with a nylon measuring tape. M ass was taken to the nearest 100g with a 10 kg or 20 kg Pesola 100 kg Pelouze scale ( Figure 2 13 ) Sex was determined by size a nd precloacal tail length Generally, t urtles with a CL> 370 mm and a PTL> 115 mm were considered males and turtles with CL >330 mm and a PTL< 115 were considered females (Dobie, 1971). When available, radiograph s were obtained using an Eklin Mark III dig ital radiograph machine and a MinXRay generator. Turtles were placed in dorsal recumbency on a l dorsal view was captured For larger turtles, multiple images were taken until the desired area was investigated. Radiographs were used to examine for the presence of ingested fishing hooks within the gastrointestinal tract. All turtles were marked by drilling combinations of marginal scutes (C agle 1952 ) and inserted with HPT12 (12.5mm) passive integrated transponder (PIT) tag in the ventrolateral tail muscle (Trauth et al. 1998; Figure 2 14 ) These are approved marking techniques for turtles (Herpetological Animal Care and Use Committee 2004). Turtles were photographed, and at least one turtle from each captured locality w as photo vouchered at the Florida Museum of Natural History (FLMNH). After measuring and marking was completed, a ll turtles were returned to their capture location within 3 4 hours of removal from trap

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28 Ultrasonic Telemetry To determine if home range vari ed between different reaches, 18 turtles were equipped with ultrasonic telemetry tags ( S onotronics CT 05 48 E ; CT 82 2 E ) in Reach 3 ( n=11 ) and Reach 1 ( n=7 ) T ransmitters were attached by drilling holes in the posterior marginals and using plastic or met al cab le ties and marine epoxy to secure to the carapace ( Figure 2 15 ) All turtles were located with a manual receiver (Sonotronics 08) and typically found by trolling with a towable hydrophone (Sonotronics TH 2 ) Once turtles were detected, I used a direction al hydrophone (Sonotronics 4) to triangulate exact locations. Turtles were located weekly at each site from December 2012 June 2013 Marcochelys are th ought to be nocturnal; therefore, in order to provide a more realist ic depiction of home range, turtles were additionally located at night in each site twice per month Upon locating a turtle, locations were marked with a GPS coordinate using a Garmin ( location error ~4 m) Location data was then imported into GIS using Environmen tal Systems Research Institute (ESRI) ArcGIS 10 software. Habitat Mapping In 2013, a 15 km sonar mapping survey was conducted in each telemetry site ( Reach 1 and Reach 3 ) on the Suwannee River using side scan sonar (SSS) (Humminbird 998 c Side Imaging syst em) Side scan sonar transmits and receives reflected acoustic signals that produce a two dimensional image of the underwater landscape (Fish and Carr, 1990). I recorded images of the river bottom with associated geographic coordinates Sonar images were georeferenced and rectified to create a continuous, instream map of each telemetry site using methods described in Kaeser

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29 and Litts (2008, 2010) Sonar maps were used with telemetry location data to help ident ify subsurface habitat used by t urtles. Bush H ook Surveys B ush hooks are a known source of ingestion of fish hooks by Macrochelys and to determine the abundance of available hooks, two surveys for bush hooks were conducted in Reach 1 and Reach 3 Bush hooks were surveyed by floating a 5 km s ection of river along each side of the river and counting the number of hanging lines with baited and non baited hooks. Data Analyses Turtle Relative Abundance and Density Capture per Unit Effort (CPUE) can be used to approximate relative ab undance CPUE for a given sampling event was determined by dividing the number of individuals captured by the total number of trap nights or effort during the sampling event ( 1 trap set over 1 night = 1 trap night) Because CPUE is a ratio and d oes not mee t ass umptions of parametric analyses, I used program R to perform a non parametric analysis of variance ( Kruskal Wallis test) to determine if CPUE was equal in each reach In addition, P rogram MARK (version 2.0 ) was used to estimate population abundance in each ecological r each Adult c apture recapture data was organized in a matrix and imported into Program MARK I estimated capture recapture probability and abundance for each reach by treating reaches as groups in Program M ARK. I fit two models. The first model assumed cap ture recap ture probability differed by reach and the second model assumed c apture recapture probability were the sam e among reaches. A closed model was used b ecause telemetry data suggests Macrochelys have

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30 limited linear home ranges with in the Suwannee River. W e assumed no immigration or emigration during this short study period Turtle Population Structure A chi square test was used to determine if sex ratio differed significantly from 1:1 Population structure was determin ed for th e entire river and for each ecological reach. A Mann Whitney Rank Sum was used to compare morphological data between sexes. A sexual dimorphism index (SDI Equation 1 ) was used to compare mean sizes between sexes (Lovich and Gibbons, 1992). Eq. 2 1 AN OVA was used to compare CL, C W, HW, PL, and mass among reaches Separate ANOVAs were conducted for males and females for each response variab le Data for all analyses were inspected to verify the assumptions of parametric analyses were satisfied and data transformations were applied when necessary. All analyses were conducted in Program R ( R Development Core Team, 2012 ). Turtle Hom e Range Telemetry was used to locate turtles in Reach 1 and Reach 3 To determine if home range varied between these two reaches, I measured the linear distance traveled between the farthest upstream and downstream locations for 15 individual turtle s To h elp minimize error, each turtle was analyzed independently All measurements were a nalyzed in ArcGIS 10 ( ESRI, 2011 ) A t test was used to determine if linear home range differed between reach and sex All statistical analyses were conducted in Program R ( R Development Core Team, 2012 )

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31 Prevalence of Ingested F ishhooks In order to determine if the abundance of available fishhooks in two different reaches had an effect on the prevalence of turtles with ingested hooks, data were examine vi sually

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32 Figure 2 1 Map of the Suwannee River. Figure 2 2 Map of the Suwannee River showing 6 ecological reaches

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33 Figure 2 3 Photographs of Reach 1 showing high limestone banks and a narrow river channel. Photos courtesy of Travis Thomas and Kevi n Enge. Figure 2 4 Photographs of Reach 2 showing an increase in channel width and a reduction of limestone banks. Photos courtesy of Travis Thomas, Kevin Enge and Tim Donovan

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34 Figure 2 5 Photographs of Reach 3 showing a wider channel and spring w ater flowing into the channel. Limestone banks are less frequent Photos courtesy of Travis Thomas and Kevin Enge. Figure 2 6 Photographs of Reach 4 showing wide channel with major spring input. Photos courtesy of Travis Thomas and Kevin Enge.

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35 Figu re 2 7 Photographs of Reach 5 showing very wide channel, emergent vegetation, and expansive flood plain. Photos courtesy of Travis Thomas and Kevin Enge. Figure 2 8 Photographs of Reach 6 (estuary) showing very wide channel, tidal salt marsh, and floo dplain creek Photos courtesy of Travis Thomas and Kevin Enge.

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36 Figure 2 9 Map of the Suwannee River showing 2 randomly selected study sites within each reach.

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37 Figure 2 10 Photographs showing traps set during this study. Photos courtesy of Travis T homas, Kevin Enge, and Tim Donovan. Figure 2 11 Photograph showing modified trapping technique utilized within the estuary. Photo courtesy of Travis Thomas and Kevin Enge.

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38 Figure 2 12 Photographs of m orphologic measurements being taken. Photos co urtesy of Travis Thomas and Kevin Enge. Figure 2 13 Photographs showing mass of adult (above) and immature (below) turtles being taken Photos courtesy of Travis Thomas and Kevin Enge.

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39 Figure 2 14 Photograph showing the insertion of a Passive Inte grated T ransponder ( PIT ) tag into the ventral tail of a Macrochelys captured in the Suwannee River. Photo courtesy of Travis Thomas and Kevin Enge. Figure 2 15 Photograp h showing the a ttachment of an ultrasonic transmitter to the posterior carapace o f a Macrochelys captured in the Suwannee River Photo courtesy of Travis Thomas and Kevin Enge.

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40 CHAPTER 3 R ESULTS Turtle Relative Abundance and Density In all, 132 individual Macrochelys were captured (161 total captures and 29 recaptures) w ith in the Suwannee River in 742 trap nights (CPUE= 0 .217) One turtle was opportunistically hand captured and 5 turtles were captured outside of the 5 km sampling sites ; however the se turtles were not i ncluded for capture recapture or CPUE analysis. Turtle s were capture d in 11 of 12 sites and 6 of 6 ecological reaches (Table 3 1) The only site that did not produce a capture was the lower estuary. When data were subdivided according to reach, capture per unit effort (CPUE) varied significantly among reache s (Kruskal Wallis F 5,57 = 21.8935, p < 0.001). Multiple pairwi se comparisons revealed R each 6 had significantly lower CPUE than R eaches 2, 3, and 4 (Figure 3 1 ). Althoug h not significantly different, R eaches 1 and 5 had an observably lower CPUE than reache s 2, 3, and 4. The model assuming different cap ture recapture by reach did not converged for several reaches due to the low number of recaptures. Perimeter estimates from t he second model which assumed a common capture recapture probability among reaches produced reasonable estimates of capture probability and recapture probability as well as abundance. Abundance estimates from this model st rongly agree d with CPUE results and showed different abundances among different reaches Reach 1 and 5 had relatively lower estimated abundance than R eaches 2, 3, and 4 (Table 3 2 ; Figure 3 2 ). Turtle Population Structure The total sample consisted of 28 ( 21.2 % ) immature individuals, 23 ( 17.4 % ) adult females and 81 ( 61.4 % ) adult males For the entire river, s ex ratios differed sig nifican tly

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41 from 1:1 ( 2 = 32.3 p < 0.00 0 1 ) and was 3.5:1 in favor of males Sex ratio varied among reaches and were significantly biased towards males in R eaches 2, 3, and 4 ; however, sex ratio did not differ significantly from 1:1 in R eaches 1 and 5 (Table 3 3) All size classes between 152 mm and 650 mm were represented The heaviest individual captured was a turtle with a mass of 57.15 k g while the lowest mass recorded was a 500 g individual. As expected, a dult males were significantly larger than adult females for CL, CW, PL, HW, and mass, and sexual dimorphism indices were 0.33 (CL), 0.28 (CW), 0.28 (PL), 0.32 (HW), and 1.29 (mass) (Table3 4) The entire sample exhibited a right skew toward larger (CL) individuals (Figure 3 3 ) but when data are examined by reach, it is obvious th at larger individuals a re observed more frequently in R eaches 2, 3, and 4 ( Figure 3 4 ). In total, 33 out of 81 (41%) adult males weighed 45 kg (100 lbs) or greater. The number of 45 kg males observed varied dramatically among reach, with the greatest numbe r of large males observed in R eaches 2, 3, and 4 (Figure 3 5 ). Adult males were significantly larger in CL CW, PL, HW, and mass within the middle river, R eaches 2, 3 and 4 (Figure 3 6 ) Adult females were not significantly different in CL and mass among reaches, but sign ificance was detected in PL in R each 2 and CW in R each 5 (Figure 3 6 ). Turtle Home Range Sixteen of the18 turtles were located after release. In Reach 3, 2 turtles were never located and 1 turtle was lost after a month of tracking and was excluded from analysis Linear home range did not vary significantly between reach (t=1.1723, p=0.2681) Turtles in Reach 3 had a mean linear home range of 2,013 m 243 m and turtles in Reach 1 had a mean linear home range of 1,533 m 329 m Ov erall, a dult

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42 males exhibited a slightly larger mean linear home range ( 1,896 m 252 m) than females (1,615 m 301 m ); however there was a no evidence that these were statistically different (t= 0.7174, p=0.4947). Although no significance was detected, several interesting behaviors were observed T urtles at each site were tracked repeatedly moving back and forth between the floodplain and the river channel with no aquatic corridor (i.e overland movement). Telemetry conducted at night found turtles were mostly active, whereas day time tracking found turtles to be inactive and under some type of cover or refuge. Sonar mapping revealed t urtles used different habitat as water levels fluctuated During high water levels turtles were located in floodplains and were more likely to be located under trees and among roots systems associated with trees (Figure 3 7) Durin g periods of lower water levels turtles were found using undercut banks large rocks and wood debris within the channel of the river (Figure 3 8) A large male t urtle was frequently located in a spring and spring run in Reach 3 ( Figure 3 9 ). Prevalence of Ingested F ish H ooks Two separate surveys for bush hoo ks were conducted in June of 2013 and September of 2013 in Reach 1 and Branford Reach 3 During the June sample, 7 bush hooks were observed in Reach 1 and 34 bush hooks were found in Reach 3 In September, 4 bush hooks in Reach 1 were observed and 24 in Reach 3; however, high water levels made lines difficult to detect. Overall, Reac h 3 averaged more bush hooks than Reach 1 Seven turtles were radiographed in Reach 1 and 12 turtles were radiographed in Reach 3 for the pre sence of ingested fishing hooks. Radiographs revealed 3 turtles, all in Reach 3 had fishing hooks within the gastr ointestinal tr act and one turtle possessed 3 fishing hooks (Figure 3 10 ) Results for the bush hook survey

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43 are shown in Figure 3 11, and although more data are needed, preliminary results suggest that a higher prevalence of bush hooks leads to higher fish hoo k ingestion by turtles.

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44 Table 3 1 Captures trap n ights, and m ean C apture P er Unit Effort ( CPUE ) by reach and s ite. Reach Site Sessions Trap Nights Captures CPUE 1 White Springs 5 52 7 0.183 Suwannee Springs 5 60 12 0.217 10 112 19 0.200 2 Dowl ing Park up 5 55 23 0.383 Dowling Park down 6 68 14 0.208 11 123 37 0.288 3 Mayo 5 60 6 0.100 Branford 6 64 24 0.361 11 124 30 0.242 4 Rock Bluff 5 60 29 0.483 Sun Springs 6 72 17 0.235 11 132 46 0.348 5 Manatee Springs 5 60 14 0.23 3 5 59 8 0.133 10 119 22 0.183 6 Estuary up 5 60 1 0.017 Estuary down 5 60 0 0.000 10 120 1 0.008 Table 3 2 Sex ratios for the entire sample and by reach. No adults were captured in Reach 6. Reach Male Female chi squared p value 1 7 5 0.3 0.563 2 26 4 16.1 < 0.005 3 18 4 8.9 < 0.005 4 21 7 7 0.008 5 9 3 3 0.083 6 Total 81 23 32.3 < 0.001

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45 Table 3 3 Morphological measurements and masses of 132 Macrochelys captured in the Suwannee River. Data consists of mean, standard deviation, and minimum maximum Body size s were compared using a Mann Whitney Rank Sum Test and a sexual dimorphism index ( Lovich and Gibbons, 1992). Immature Female Male (n = 28) (n = 23) (n = 81) P SDI CL (mm) 243.46 415 550.3 < 0.001 63.8 33.1 62.9 0.33 (152 325) (344 470) (431 650) CW (mm) 214.78 356.9 457.1 < 0.001 57.1 29.7 46.64 0.28 (134 292) (295 407) (363 524) PL (mm) 186.82 312.9 399 < 0.001 49.1 27.5 38.2 0.28 (116 261) (253 367 ) (325 458) HW (mm) 81.64 133.5 176.4 < 0.001 19.7 12 20.4 0.32 (53 109) (107 152) (138 222) mass (kg) 4.08 16.46 37.75 < 0.001 2.8 3.5 11.3 1.29 (0.5 8.7) (10 22.5) (18 57.1) Table 3 4 Mean linear home r ange of Mac rochelys with standard error for sex and reach. Sex n Mean l inear home r ange (m) Male 11 1896 252 Female 4 1615 301 Reach Reach 1 6 1533 329 Reach 3 9 2013 243

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46 Figure 3 1 Catch P er Unit Effort ( CPUE ) by reach with standard error. Letters indicate significance. Reach 1 and 5 had relatively lower estimated abundance than Reaches 2, 3, and 4 Figure 3 2 Estimation of adult turtle density by reach from a c losed population model with standard error Estimate is for 10km of river in each reach.

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47 Figure 3 3 Size distribution for Macrochelys captured in the Suwannee River from 2011 2013.

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48 Figure 3 4 Size distribution for Macrochelys captured in the Suwannee River by reach from 2011 2013

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49 Figure 3 5 Frequencies of captured Macrochelys in the Suwannee River 45 kg by reach.

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50 Figure 3 6 M easurements of A) carapace length, B) mass, C) carapace width D ) plastron length and E) head width of adult male and female Macrochelys using AN OVA with reach as a factor L etters indicate significance.

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51 Figure 3 7 Map showing 4 turtles located within the floodplain during high water levels in Reach 1. Different colors represent different turtles. Figure 3 8 Sonar map image showing turtle #115 frequently located aroun d a cluster of submerged woody debris.

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52 Figure 3 9 Map showing turtle #31 frequently located in a small spring and spring run Figure 3 10 Radiograph showing 3 fishing hooks in the upper gastrointestinal tract of a Macrochelys from the Branford site (Reach 3)

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53 Figure 3 11 Plot showing the relationship between number of bush hooks present and ingested fish hooks found in turtles in Reach 1 (circle) and Reach 3 (triangle). Although a trend seems to emerge, more data are needed to investigate this potential threat.

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54 CHAPTER 4 D ISCUSSION / CONCLUSION A previous study found Macrochelys to be absent within the Suwannee River in Georgia and this was a major concern due to the Suwannee River population of Macrochelys being genetically unique from other populations (Jenson and Birkhead, 2003; Roman et al., 1998). Although Moler (1996 ) captured Macrochelys in the Suwannee River in Florida as part of a statewide distribution survey, questions and concerns remained regarding the st atus of this unique population. Data from this study show that Macrochelys within the Suwannee River are more numerous than previously thought Hypotheses Revisited I predicted that alligator snapping turtle abundance would increase in the middle and lower reaches relative to upper reach (Reach 1) due to differences in habitat driven by water chemistry and geomorphic riverine processes predicted by the RCC My prediction was partially confirmed as turtle relative abundance and estimated density was lower in the upp er reach and higher in the middle reaches (Reaches 2 4); however, I found reduced abundance within the lower reaches (Reach es 5 and 6). In fact, Reach 6 had the lowest relative abundance. These results were supported by capture per unit effort ( CPUE ) data and density estimates derived from a closed population model. I predicted that alligator snapping turtle s would exhibit smaller size classes and different population structure in the upper reach relative to the middle and lower reaches due to differing l evels of productivity predicted by the RCC Examination of reach specific population data revealed that turtles within the middle reaches (Reaches 2 4)

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55 had sex ratios skewed toward males and significantly different from 1:1. Not only were there more males within the middle reaches, but males in the middle reaches were significantly larger in size when compared to males in the upper (Reach 1) and lower reaches (Reaches 5 and 6). Females did not show this pattern, but significant differences were observed for females in PL in Reach 2 and CW in Reach 5. I predicted that alligator snapping turtles would exhibit smaller home ranges in Reach 3 than turtles in Reach 1 due increases in river productivity from upstream to dow nstream. This was not confirmed. No signif icant difference was detected in linear home ranges between reaches. I predicted the prevalence of ingested fish hooks would be higher in the reach with the most observed bush hooks. We observed more bush hooks set in Reach 3 than Reach 1 and radiographs revealed that turtles captured in Reach 3 ingested fish hooks whereas turtles captured in Reach 1 had not Discussion Overall, the mean CPUE for this study was 0.22, which is comparable to other studies conducted in Florida, Arkansas, and Oklahoma (Mole r 1996; Wagner et al. 1996; Trauth et al. 1998; Riedle et al., 2008 ) Jensen and Birkhead (2003) found a slightly lower CPUE (0.20) during a survey of rivers in Georgia but in 53 trap nights, no Macrochelys was captured in the Suwannee River ; low pH an d aspects of commercial harvest were possible explanations (Jensen and Birkhead 2003) The authors alternatively suggested that Macrochelys may not be common in the easternmost part of its range (Jensen and Birkhead 2003), but data from my study cast dou bt on that hypothesis Capture per unit effort data from my study revealed t hat rel ative abundance is low in the upper and lower reaches (R eaches 1 and 5) of the Suwannee River

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56 whereas the middle reaches (R eaches 2, 3, and 4) have the highest relative abu ndance Results from the closed population model suggested that the middle reaches (R eaches 2, 3, and 4) have t h e highest estimated density of turtles. The closed population model assume d no immigration or emigration, and I beli eved this to be appropriate because telemetry data revealed small linear home ranges ( ~ 1 2 km) in the Suwannee River Sampling with baited traps may be biased towards adult turtles because immature individuals are more likely to lure for prey ( Pritchard 2006 ); therefore, I only incl uded adult turtles in the model. The o verall estimated population density was 3.5 adults /km for the entire river, though density was not equal along the river. The upper and lower reaches (R eaches 1 and 5) had the lowest estimated abundance ( 1.7 adults/km and 2 adults/ km), whereas the middle reaches (R eaches 2, 3, and 4) had the highest estimated abundance (3.75/adults/km, 2.6 adults/km, 4.3 adults/km ) The model strongly agreed with CPUE results and provides further evidence that turtle relative abundance and density are heavily influenced by river reach. Other studies e stimated population densities, including juveniles, to be turtles /km in Oklahoma streams (Riedle et al. 200 8 ) and 18 turtles/km in an Arkansas stream that had been commercially harvested in the past (Howey and Dinkelacker 2013) Although these studies incorporated immature individuals, even if only adult s are considered, the estimate s are much higher than those found in this study. One explanation could be detectability. Other studies have been restricted to s maller streams and rivers, whereas my stud y was conducted in a large free flowing river. Traps ar e typically more effective in smaller streams because the bait scent covers a greater percentage of the area and

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57 potentially both banks ; however, in a large river, coverage is reduced due to the sheer volume of water and the distance between banks. In tot al, males were captured significantly more often than females and immature individuals (3.5:1 sex ratio); conversely, other studies found predominantly females (Howey and Dinkela cker 2013, Lescher et al. 2013) or equal sex ratios (Trauth et al. 1998, Jense n and Birkhead 2003, Boundy and Kenn edy 2006, Riedle et al. 2008). Although our tot al sample was m ale biased, sex ratios were not significantly different from 1:1 within R eaches 1 an d 5. R eaches 2 4 were extremely male biased which skewed the entire sampl e. Although individuals of breeding size were captured in all reaches except Reach 6 ( estuary ), my data indicate that sex ratios are different along the river. Macrochelys has temperature d ependent sex deter mination, and although we did not locate any nest s during this stu dy, past studies have shown that sandy beaches and w armer nest temperatures produce more females (Ewert, 1994). Nesting habitat changes as the river makes its way downstream towards the Gulf of Mexico There are more upland and open nestin g habitat s available in the upper river ( Reach 1 ), and as the elevation decreases and f loodplains become more extensive nesting habitat becom es potentially more shaded. This pattern could explain why turtles are male biased in the middle river (reaches 2 4 ). However, the sex ratio within Reach 5 was not significantly different from 1:1 and this reach has nesting habitat that is very similar to the middle reaches. Therefore, difference s in nesting habitat among reaches is an unlikely explanation for the unequal sex ratios found in this study. A more likely explanation for biased sex ratios in the middle reaches is that a dult males, which dominate the middle reaches, may control juvenile and female populations by

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58 competitive exclusion forcing smaller ind ividuals into less desirable habitat. Although Macrochelys are occasionally found in estuarine habitat (Ja ckson and Ross, 1971; Ewert, 2006), my data suggest that Macrochelys are rare within the Suwannee estuary This may be due to the lack of appropriate habitat and an influx of salt water. A study of the upper Suwannee River e stuary found maximum salinity concentrations as high as 31 ppt (Tillis, 2000 ) The salinity of sea water is approximately 35 ppt. Overall, I captured a higher proportion of large tur tles than any other published study, but most large turtles were captured in t he middle reaches (R eaches 2 4) Pritchard (1979) proposed that Macrochelys may wander upstream until they reach large sizes, but data from this study cast doubt on this hypothes is The headwaters are far less productive and would not be ideal for optimal growth. D ata from this study suggest that Macrochelys are most abundant and largest in the more productive sections of the river. Adult males were significantly larger than femal es in CL, CW, PL, HW, and mass within the middle reaches (Reaches 2 4). These data suggest that males potentially grow to larger size s within these highly productive reaches. Females were not significantly different in CL, HW, and mass although significan t differences were detected in PL (Reach 2) and CW (Reach 5). This could potentially be due to low statistical power caused by the small female sample size. Boundy and Kenney (2006) reported the heaviest turtle captured in a study (51.4 kg) to date, and th e heaviest turtle reported in my study had a larger mass (57.1 kg ). Pritchard (2006) reported much heavier turtles but many of these weights may represent estimated weights and should be interpreted with caution. As a further complication, Pritchard (2006 ) reports to the size of many captive animals. In captivity, Macrochelys readily eat s and lack s normal

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59 movement pa tterns. This has most likely le d to captive turtles being obese, and their weights are not representative of wild turtles For example, a turt le in the Brookfield Zoo in Chicago, Illinois, grew to 66 cm CL and weighed 114 kg (Pritchard 2006), whereas a n apparently healthy turtle from my study measured 65 cm CL and weighed 54.5 kg. Studies in Georgia, Louisiana, Missouri, Arkansas, and Oklahoma found a lack of large adult turtles, which has usually been attributed to historical harvest (Wagner et al. 1996, Jensen and Birkhead 2003, Boundy and Kennedy 2006, Riedle et al. 2006 ; 2008 East et al. 2013, Howey and Dinkelacker 2013, Lescher et al. 201 3). Harvest has been well documented in this species and has certainly played a role in declines in many populations (Pritchard, 2006). The reported rarity of Macrochelys in the uppe r reaches of the Suwannee River has also been attributed to harvest ( Jense n and Birkhead 2003 ; Pritchard, 2006). Many of these population parameters can potentially be explained by s imple ecological stream theory The upper Suwannee River ( Reach 1 ) derives most of its water from direct surface runoff, and the water is acidic h ig h in organic material and dark in color (Hornsby et al. 2000) which inhibits benthic and water column photosynthesis Due to the low pH, many of the nutrients are biologically unavailable As the river flows downstream it passes over an important geol og ical feature known as the Cody S carp. The Cody S carp is a karst escarpment that divides the Northern Highlands and Gulf Coastal Lowlands physiographic regions (Hornsby et al. 2000) The Cody Scarp possesses mostly carbonate rock (limestone) near or at t he surface. Upon reaching the Cody Scarp (Reach 2) the acidic water from upstream comes into contact with carbonate rock that buffers the water, resulting in an increase in pH. This increase in pH causes nutrients that were previous unavailable to become

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60 biologically available increasing invertebrate and fish resources This increase in the potential turtle prey base could explain the dramatic increase in turtle CPUE, density, and size from Reach 1 to Reach 2. the river r eceives increasing amounts of water from the Floridan aquifer, which changes the water to a slightly colored, alkaline stream (Hornsby et al. 2000) and increases aquatic productivity My data indicate that turtle density and size are the highest from down stream of the Cody Scarp to Reach 4, but turtle CPUE, density, and size decrease in Reach 5 One explanation for this is saltwater incursion The Suwannee River experiences tidal influences within R each 5 (Hornsby et al. 2000) and d uring periods of low f low, pockets of salt water have the potential to form on the river bottom. Macrochelys are bottom dwelling turtles, and saltwater incursion could potentially reduce the availability of preferred habitat. While the ecological reaches described by Hornsby et al. (2000) help to distinguish different sec tions of river, my data suggest that the Cody Scarp is perhaps the most important influence on the population dynamics of Macrochelys in the Suwannee River. During my telemetry study, t wo turtles were never loc ated a fter release, and one turtle was lost after being located consistently for a month. Although extreme movements have been reported in this species (Pritchard, 2006), I searched 32 km upstream and 35 km downstream of the release site with no success. T he most likely explanation is equipment failure. Macrochelys have been known to wedge themselves under rocks and limestone banks, and this behavior could have resulted in damage to the transmitters Turtles in Reach 3 had a larger mean home range, but ther e was a large amount of inter individual variation and home range did not differ significantly

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61 between reaches. A lthough the mean linear home range was greater in males than females, no significant difference was detected This is contrary to a study in O klahoma in which adult females tended to have larger home ranges than adult males and j uveniles had larger home ranges than adults (Riedle et al. 2006). In my study, s mall sample size could have played a factor in det ecting a significant difference. Alt hough no significant differences were detected between sexes and reaches in linear home range size I observed several interesting behaviors. Two large male turtles (>45kg) were frequently located in springs and spring runs within Reach 3 Springs may prov ide a ther mally stable refuge for turtles. A study conducted in the Santa Fe River, a tributary of the Suwannee River, resulted in very few Macrochelys captured in springs. It is important to note that springs trapped in the Santa Fe River experience high levels of recreation (e.g. swimming, boating, and fishing) and this could explain the rarity of Macrochelys within these habitats ( Johnston, pers. obs. ). My data confirm that Macrochelys do use spring habitats, but the spring in my study is very small and lacks recreational use Unaltered floodplain springs could be important refuges for Macrochelys within the Suwannee River drainage and more research is needed to examine habitat use in Macrochelys During periods of high water, t urtles were observed in e ach site moving from the river channel into the floodplain During high water periods the floodplains were inundated with water and likely utilized as n ew foraging habitat by turtles. These floodplains remain ed inundated for weeks W hen water levels fell, the aquatic corridors between the river channel and the floodplain disappeared Surprisingly, t urtles were located on multiple occasions moving back and forth between the floodplain and

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62 channel without an aquatic corridor. Past studies claim that overland movement is rare or absent in this species ( Pritchard 2006) but my data suggest that these movements do take place and could be more common than previously thought Additionally, turtles were observed using 2 4 core sites, which has bee n reported in prev ious studies (Riedle et al. 2006) C ore sites typically consisted of subsurface rocks, w oody debris, and undercut banks. As water levels fluctuated, turtles were located in different habitat types. Side scan sonar (SSS) revealed t urtles were usually ass ociated with limestone bank outcrops subsurface rocks, or woody debris including deadhead logs (pre cut timber lost during transport), during low water periods. A s water levels increased, turtles were located in a nd around fallen trees and root systems t hat were previously out of the water. This suggests that Macrochelys habitat preferences may change with availability. Data from this study suggest that Macroche l ys rely on submerged woody debris as habitat an d refuge, especially during low water periods w hen other habitat types are perched. The state of Florida initiated a deadhead log removal program in 2000. From 2000 to 2008, more than 16,000 logs were is likely a conservative number (Kaeser and Litts, 2008). The removal of any woody debris from the Suwannee River could have a negative impact on Macrochelys due to the high importance of woody debris as a primary refuge during low water periods. Ingested fish hooks can perforate the digestive tract lining and monofilament or gel spun fishing line attached to the hook can cause severe digestive blockage and potentially death in turtles (H e ard, pers. obs. ). Ingested hooks are likely the result of bush hooks, which are single hooks suspended from tree branches to catch catfish and

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63 other forms of wildlife. Bush hooks are typically baited and set in the eveni ng and left out over night. Because Macrochelys are primarily nocturnal, they have a higher chance of an encounter with a bush hook than a manned fishing line. A n FWC regulation requires that bush hooks be clearly labeled with the However, most bush hooks we observed were not labeled. My study found bush hooks to be more abundant in Reach 3 This is most likely due to higher fish abundance and greater access t o the river Although our sample size was small, the results provided some insight We found three individuals, all in Reach 3 with ingested fish hooks and one turtle had ingested three hooks. These turtles appeared healthy, and two of the three turtles have been recaptured and equipped with telemetry transmitters These turtles have exhibited normal movements. Fish hooks are possibly not the primary cause for concern; the associated fishing line attached to the fishhook may pose the greatest health thre at. Additionally, a turtle in Dowling Park (Reach 2) was observed upon capture to have a fish hook embedded in the upper left forelimb. The hook also had a line weight and about 3 feet of heavy test braided monofilament attached. The hook was removed and the turtle released. Further studies are necessary to determine the impact if any, of ingested hooks and associated fishing tackle on Macrochelys populations Other than ingested fishhooks, Macrochelys faces additional threats within the Suwannee River dr ainage. Injuries obtained from boat propellers are one concern. Much of the Suwannee R iver receive s heav y recreational use by boaters, especially the middle and downstream portions of river. Boat p rop eller scars were observed on the carapaces of eight tur tles and some damage was extensive but had healed (Figure 4 1) If the population in the Suwannee River is recognized as a new species it would

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64 likely meet the criterion of threatened in Florida because of its restricted distribution (FWC 2011) Because this population is restricted to a single drainage, a catastrophic chemical spill or similar event could potentially be devastating These types of events seem unlikely; however, in 2013 the c ity of Valdosta had major sewage spills into the Withlacoochee River a tributary of the Suwannee River, from its wastewater treatment plant in which spilled millions of gallons of solid waste into the drainage. Bycatch of other turtle species primarily consisted of the pond slider ( Trachemys scripta ), Suwannee coot er ( Pseudemys suwanniensis ), and Florida softshell turtle ( Apalone ferox ) but included the peninsula cooter ( Pseudemys peninsularis ), Florida red bellied cooter ( Pseudemys nelsoni ), loggerhead musk turtle ( Sternotherus minor ), and Florida snapping turtle ( Chelydra serpentina ). Eight exotic red eared sliders were captured throughout the river ( T rachemys scripta elegans ). Numerous fish species were captured including a bull shark ( Carcharhinus leucas ). Conclusions F isheries biologists have used basic princip les of stream ecology to help explain population abundance and community structure of organisms within fluvial systems. My data suggest that the RCC provides a useful framework for understanding the dynamics of fluvial process and how they affect the distr ibution of riverine freshwater turtles Lower densities of Macrochelys should be expected in less productive sections of river because these sections lack the resources needed to sustain high population densities. Furthermore, low turtle densities fo und in sections of rivers with low biological productivity are not always indicative of harvest or an unhealthy population but they are caused by natural riverine processes that help shape population dynamics within fluvial systems. The RCC could potentia lly be a practical tool to help resource managers

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65 predict abundance and density levels in order to help focus conservation efforts within riparian system s My data indicate that Macrochelys is more abundant in the Suwannee than previously thought and provi des a framework for its future conservation and management.

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66 Figure 4 1 Photographs of damage ascertained from a boat propeller on 2 Macrochelys in the Suwannee River. Photos courtesy of Travis Thomas and Kevin Enge.

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67 REFERENCES Allen, E. R ., and W. T. Neill. 1950. The alligator snapping turtle Macrochelys temminckii in Florida. Ross Allen's Reptile In stitute Special Publication 4:1 15. Boundy, J., and C. Ke nnedy. 2006. Trapping survey results for the alligator snapping turtle ( Macrochelys t emminckii ) in southeastern Louisiana, with comments on exploitation. Cheloni an Conservation and Biology 5:3 9. Cagle, F. R. 1939. A system of marking turt les for future identification. Copeia 1939:170 173. Ceryak, R., M. S Knapp, and T. Burnson. 1983. Th e geology and water resources of the Upper Suwannee River Basin, Florida. Bureau of Geology, Division of Resource Management, Florida Department of Natural Resources and Suwannee River Water Management Distri ct, Tallahassee, Florida, USA. 165pp. Decamps, H. 2011. River networks as biodiversity hotlines. Co mptes Rendus Biologies. 334:420 434. Dobie, J. L. 1971. Reproduction and growth in the alligator snapping turtle, Macroclemys temminck i i (Troost). Copeia 1971:645 658. Duncan, W. W., G. C. Poole, and J. L. Meyer. 2009. Large channel confluences influence geomorphic heterogeneity of a southeastern United States river. Water Resources Research 45:9. East, M. B., J. D. Riedle, and D. B. Ligo n. 2013. Temporal changes in an alligator snapping turtle ( Macro chelys temminckii ) population. Wildlife Research 40:77 81. Echelle, A. A., J. C. Hackler, J. B. Lack, S. R. Ballard, J. Roman, S. F. Fox, D. M. Leslie, Jr., and R. A. Van Den Bussche 2010. Conservation genetics of the alligator snapping turtle: cytonuclear evid ence of range wide bottleneck effects and unusually pr onounced geographic structure. Conservation Genetics 11:1375 1387. Elsey, R. M. 2006. Food habits of Macrochelys temminckii (alligator snapping turtle ) from Arkansas and Louisiana. Southeastern Naturali st 5:443 452. Ernst, C H., and J. E. Lovich. 2009. Turtles of the United State s and Canada. Second edition. Johns Hopkins University Pr ess, Baltimore, Maryland, USA. 827pp. ESRI 2001. ArcGIS Desktop: Release 10. Redlands, CA: Environmental Systems Researc h Institute. Ew ert, M. A., and D. R. Jackson. 1994. Nesting ecology of the alligator snapping turtle ( Macroclemys temminckii ) along the lowe r Apalachicola River, Florida. Florida

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68 Game and Fresh W ater Fish Commission, Nongame Wildlife Program Report NC89 0 2 0, Tallahassee, Florida, USA. 45pp. Ewert, M. A., D. R. Ja ckson, and P. E. Moler. 2006. Macrochelys temmincki i alligator snapping turtle. Pages 58 71 in P. A. Meylan, editor. Biology and co nservation of Florida turtles. Chelonian Research Monographs No. 3. Fish, J. P., and H. A. Carr. 1990. Sound underwater images, a guide to the generation and interpretation of side scan sonar data. Lower Cape Publishing, USA. Ha ll, H. H. and H. M. Smith. 1947. Selected records of reptiles and amphibians from southeaster n Kansas. Transactions of the K ansas Academy of Science 49 (4) : 447 454. Harrel, J. B., and G. L. Stringer. 1997. Feeding habits of the alligator snapping turtle ( Macroclemys temminckii ) as ind icated by teleostean otoliths. Herpetological Review 28:185 18 7. Herpetological Animal Care and Use Committee. 2004. Guidelines for use of live amphibians and reptiles in field and laboratory research. Second edition. American Society of Icht hyologists and Herpetologists. 43pp. Holcomb, S. R., and J. L. Carr. 2013. Mammalian depredation of artificial alligator snapping turtle ( Macrochelys temminckii ) nests in North Louisiana. Southeastern Naturalist 12:478 491. Hornsby, D., R. A. Mattson, and T. Mirti. 2000. Surface water quality and biological mo nitoring. Annual Rep ort 1999. Suwannee River Water Management Distr ict Technical Report WR 00 04. 148pp. Howey, C. A. F., and S. A. Dinkelacker. 2013. Characteristics of a historically harvested alligator snapping turtle ( Macrochelys temminckii ) population. Copeia 2013:58 63. Jackson, C G., Jr., and A. Ross. 1971. The occurrence of barnacles on the alligator snapping turtle, Macroclemys temminckii Troost Journal of Herpetology 5:188 189. Jensen, J. B., and W. S. Birkhead. 2003. Distribution and status of the alligator snap ping turtle ( Macrochelys temminckii ) in Georgia Southeastern Naturalist 2:25 34. Johnson, S. 1989. Population status of the alligator snapping turtle ( Macroclemys t emminckii ) in the Flint River. Annual performance report, Georgia Department of Natural Re souces, Forsyth, Georgia, USA. 11pp.

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69 Kaeser, A. J., and T. L. Litts. 2008. An assessment of deadhead logs and large woody debris using side scan sonar and field surveys in streams of sout hwest Georgia. Fisheries 33:589 597. Kaeser, A. J., and T. L. Litts. 2010. A novel technique for mapping habitat in navigable streams using low cost side scan sonar. Fisheries 3 5:163 174. Lescher, T. C., J. T. Briggler and Z. Tang Martinez. 2013. Relative abundance, population structure, and conservation of alligator snapp ing turtles ( Macrochelys temminckii ) in Missou ri between 1993 1994 and 2009. Chelonian Conservation and Bio logy 12:163 168. Lovich, J. E. and J. W. Gibbons 1992. A review of techniques for quantifying sexual size dimorphism. Growt h, Development and Aging 56:269 281. Moler, P. E. 1996. Alligator snapping turtle distri bution and relative abundance. Fi nal Report, Study Number 7544. Florida Game and Fresh Water Fish Commissi on, Tallahassee, Florida, USA. 13pp. Pittman, J. R., H. H Hatzell, and E. T. Oaksford. 1997. Spring contributions to water quantity and nitrate loads in the Suwannee River during base blow in Ju ly 1995. U.S. Geological Survey Water Resources Investigations Report 97 4152. U.S. Geological Surv ey, Tallahassee, Florida, USA. 11pp. Pritchard, P C. H. 1979. Encyclopedia of Turtles. T.F.H. Publicat ions, Inc., Neptune, New Jersey USA. 895 pp. Pritchard, P. C. H. 2006. The alligator snapping turtle: biology and conservation. Second edition. Krieger Publishing C ompany, Malabar, Florida, USA. 140pp. R Development Core Team. 2012 R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3 900051 07 0, URL http://www.R project.org/. Raulston, M., C. Johnson, K. Web ster, C. Purdy, and R. Cerya k. 19 98. Suwannee River editors. Water resources atlas of Florida. Institute of Science and Public Affairs, Florida State University, Tallahassee, Florida, USA. Reed, R. N., J. D. Cong don, and J. W. Gibbons. 2002. The alligator snapping turtle [ Macroclemys ( Macrochelys) temminckii ]: a review of ecology, life history, and conservation, with demographic analyses of the sustainability of take from wild populations. Report to Divisio n of Scientific Authority, United Sta tes Fish and Wildlife Service. Savannah River Ecology Laborator y, Aiken, South Carolina, USA. 17pp.

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70 Riedle, J. D., P. A. Shipman, S F. Fox, and D. M. Leslie, Jr. 2005. Status and distribution of the alligator snapping turtle Macrochelys temminckii in Oklahoma. Southwestern Naturalist 50:79 84. Riedle, J. D., P. A. Shipman, S. F. Fox, and D. M. Leslie, Jr. 2006. Microhabitat use, home range, and movements of the alligator snapping turtle, Macrochelys temminckii in Oklahoma. Southwestern Naturalist 51:35 40. Riedle, J. D., P. A. Shipman, S. T. Fox, J. C. Hackler, and D. M. Leslie, Jr. 2008. Population structure of the alligator snapping turtle, Macrochelys temminckii, on thewestern edge of its distribution. Chelonian Conservation and Biology 7:100 104. Roman, J., S. D. Santhuff, P. E. Moler, and B. W. Bowen. 1999. Population structure and cryptic evolutionary units in the alligator snapping turtle. Conservation Biology 13: 135 142. Roy, A. H., A. D. Rosemond, D. S. Leigh, M. J. Paul, and J. B. Wallace. 2003. Habitat specific responses of stream insects to land cover disturbance: biological consequences and monitoring implications. Journal of the North Americ an Benthological Society 22:292 307. Shipman, P.A., Edds, D.R. and L. E.Shipman. 1995. Distribution of the alligator snapping turtle ( Macroclemys temminckii ) in Kansas. Transactions of the Kansas Academy of Science, 98 : 83 91. Shipman, P. A., and A. N eeley 1998. Alligator snapping turtle trap, mark, and telemetry project. Final report to the Missouri Department of Conservation, Jefferson City. Sloan, K. N., and D. Taylor. 1987. Habitats and movements of adult alligator snapping turtles in northeast Louisiana. Proceedings o f the Annual Conference of the Southeastern Association of Fis h and Wildlife Agencies 41: 343 348. Sloan, K. N., K. A. Buhl mann, and J. E. Lovich. 1996. Stomach contents of commercially harvested adult alligator snapping turtles, Macroclemys temminckii C helonia n Conservation and Biology 2:96 99. Spindel, E. L., J. L. Dobie, and D. F Buxton. 1987 Functional mechanisms and histologic composition of the lingual appendage in the alligator snapping turtle, Macroclemys temminckii (Troost) (Testudines: Chelydr idae). Journal of Morphology 194:287 301. Sutherland, A. B., J. L. Meyer, and E. P. Gardiner. 2002. Effects of land cover on sediment regime and fish assemblage structure in four southern Appalachian stre ams. Freshwater Biology 47:1791 1805.

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71 Til lis, G. M 2000 Flow and salinity characteristics of the u pper Suwannee River e stuary, Florida. Water Resources Investigations Report 99 4268. U.S. Geological Survey, Tallahassee, Florida. Trauth, S. E. J. D. Wilhilde, and A. Holt. 1998. Population structure and movement patterns of alligator snapping turtles ( Macroclemys temminckii ) in northeastern A rkansas. Chelonia n Conservation and Biology 3:64 70. Townsend, C. R. 1996. Concepts in river ecology: Pattern and process in the catchment hierarchy. Archiv fuer Hydrobiologie Supplement 113:3 21. T ucker, A. D., and K. N. Sloan. 1997. Growth and reproductive estimates from alligator snapping turtles, Macroclemys temminckii taken by commercial harvest in Louisiana. Chelonian Conservation and Biology 2: 587 592. U.S Fish and Wildlife Service. 1984. Endangered and threatened wildlife and plants; finding on a petition to list the alligator snapping turtle as a threatened species. Federal Register 49:7416 7417. U .S. Fish and Wildlife Service. 2005. Inclusion of alliga tor snapping turtle ( Macroclemys [= Macrochelys ] temminckii ) and all species of map turtle ( Graptemys spp .) in Appendix III to the Convention on International Trade in Endangered Sp ecies of Wild Fauna and Flora. Federal Register 70:74700 74712. Vannote, R. L., G. W. Minshall, K. W. Cummins, J. R. Sedell, and C. E. Cushing. 1980. River continuum concept. Canadian Journal of Fisher ies and Aquatic Sciences 37:130 137. Ward J. V. 1989 The four dimensional nature of lotic ecosystems. Journal of the North America n Benthological Society 8:2 8. Wagner, B K., D. Urbston, and D. Leek. 1996. Status and distribution of alligator snapping turtles in Arkansas. Proceedings of the Annual Conference of Southeastern Association of Fi sh and Wildlife Agencies 50:264 270. Walte rs, D. M., D. S. Leigh, M. C. Freeman, B. J. Freeman, B. J., and C. M. Pringle. 2003. Geomorphology and fish assemblages in a Piedmont river basin, U.S.A. Freshwater Biology 48:1950 1970. Woolsey, L. B. 2005. Population structure and reproduction of all igator snapping turtles, Macrochelys temminckii at Black Bayou Lake National Wildlife Re fuge. M.S. Thesis, University of Louisiana at M onroe, Monroe, Louisiana, USA. 59pp. S tackpole Books, Harrisburg, PA. 208 pp.

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72 BIOGRAPHICAL SKETCH Travis M. egree in 2009 fro m the University of Florida in n atural resources c onservation with a minor in wildlife ecology and c onservation. He is currently pursui n g a m d egree in wildlife ecology and c onversation under the supervision of Dr. Perran Ross. His primary research is focused on chelonian conservation and ecology. C urrent ly his research focuses on geomorphic riverine processes and its effect on the population dynamics of the alligator snapping turtle in the Suwannee River. He was hired by the Florida Fish and Wildlife Conservation Commission in 2009, and he has worked on numerous projects concerning reptile and amphibian ecology. Previously, he worke d for three years at the Florida Museum of Natural History in the Herpetology Department under Dr. Kenneth Krysko. He has spent time as a volunteer on numerous projects in Kenya, Africa, under the supervision of Leigh Ecclestone and the Kenyan Wildlife Ser vice.