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McCaffrey KR, Balaguera-Reina SA, Falk BG, Gati EV, Cole JM, Mazzotti FJ. How to estimate body condition in large lizards? Argentine black and white tegu (Salvator merianae, Duméril and Bibron, 1839) as a case study. PLoS One 2023; 18:e0282093. [PMID: 36827271 PMCID: PMC9955610 DOI: 10.1371/journal.pone.0282093] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Body condition is a measure of the health and fitness of an organism represented by available energy stores, typically fat. Direct measurements of fat are difficult to obtain non-invasively, thus body condition is usually estimated by calculating body condition indices (BCIs) using mass and length. The utility of BCIs is contingent on the relationship of BCIs and fat, thereby validation studies should be performed to select the best performing BCI before application in ecological investigations. We evaluated 11 BCIs in 883 Argentine black and white tegus (Salvator merianae) removed from their non-native range in South Florida, United States. Because the length-mass relationship in tegus is allometric, a segmented linear regression model was fit to the relationship between mass and length to define size classes. We evaluated percent, residual, and scaled fat and determined percent fat was the best measure of fat, because it was the least-associated with snout-vent length (SVL). We evaluated performance of BCIs with the full dataset and within size classes and identified Fulton's K as the best performing BCI for our sampled population, explaining up to 19% of the variation in fat content. Overall, we found that BCIs: 1) maintained relatively weak relationships with measures of fat and 2) splitting data into size classes reduced the strength of the relationship (i.e., bias) between percent fat and SVL but did not improve the performance of BCIs. We postulate that the weak performance of BCIs in our dataset was likely due to the weak association of fat with SVL, the body plan and life-history traits of tegus, and potentially inadequate accounting of available energy resources. We caution against assuming that BCIs are strong indicators of body condition across species and suggest that validation studies be implemented, or that alternative or complimentary measures of health or fitness should be considered.
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Affiliation(s)
- Kelly R. McCaffrey
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Sergio A. Balaguera-Reina
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Bryan G. Falk
- South Florida Natural Resources Center, National Park Service, Homestead, Florida, United States of America
| | - Emily V. Gati
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Jenna M. Cole
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Frank J. Mazzotti
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
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2
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Udell B, Martin J, Romagosa C, Waddle H, Johnson F, Falk B, Yackel Adams A, Funck S, Ketterlin J, Suarez E, Mazzotti F. Open removal models with temporary emigration and population dynamics to inform invasive animal management. Ecol Evol 2022; 12:e9173. [PMID: 35991280 PMCID: PMC9382647 DOI: 10.1002/ece3.9173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 06/09/2022] [Accepted: 07/12/2022] [Indexed: 11/07/2022] Open
Abstract
Removal sampling data are the primary source of monitoring information for many populations (e.g., invasive species, fisheries). Population dynamics, temporary emigration, and imperfect detection are common sources of variation in monitoring data and are key parameters for informing management. We developed two open robust-design removal models for simultaneously modeling population dynamics, temporary emigration, and imperfect detection: a random walk linear trend model (estimable without ancillary information), and a 2-age class informed population model (InfoPM, closely related to integrated population models) that incorporated prior information for age-structured vital rates and relative juvenile availability. We applied both models to multiyear, removal trapping time-series of a large invasive lizard (Argentine black and white tegu, Salvator merianae) in three management areas of South Florida to evaluate the effectiveness of management programs. Although estimates of the two models were similar, the InfoPMs generally returned more precise estimates, partitioned dynamics into births, deaths, net migration, and provided a decision support tool to predict population dynamics under different effort scenarios while accounting for uncertainty. Trends in tegu superpopulation abundance estimates were increasing in two management areas despite generally high removal rates. However, tegu abundance appeared to decline in the Core management area, where trapping density was the highest and immigration the lowest. Finally, comparing abundance predictions of no-removal scenarios to those estimated in each management area suggested significant population reductions due to management. These results suggest that local tegu population control via systematic trapping may be feasible with high enough trap density and limited immigration; and highlights the value of these trapping programs. We provided the first estimates of tegu abundance, capture probabilities, and population dynamics, which is critical for effective management. Furthermore, our models are applicable to a wide range of monitoring programs (e.g., carcass recovery or removal point-counts).
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Affiliation(s)
- Bradley Udell
- Wildlife Ecology and ConservationUniversity of FloridaGainesvilleFloridaUSA
| | - Julien Martin
- Wetland and Aquatic Research CenterU.S. Geological SurveyGainesvilleFloridaUSA
- Eastern Ecological Science CenterU.S. Geological SurveyLaurelMarylandUSA
| | - Christina Romagosa
- Wildlife Ecology and ConservationUniversity of FloridaGainesvilleFloridaUSA
| | - Hardin Waddle
- Wetland and Aquatic Research CenterU.S. Geological SurveyGainesvilleFloridaUSA
| | - Fred Johnson
- Department of BioscienceAarhus UniversityRøndeDenmark
| | - Bryan Falk
- Fort Collins Science CenterU.S. Geological SurveyFort CollinsColoradoUSA
- South Florida Natural Resources CenterNational Park ServiceHomesteadFloridaUSA
| | - Amy Yackel Adams
- Fort Collins Science CenterU.S. Geological SurveyFort CollinsColoradoUSA
| | - Sarah Funck
- Florida Fish and Wildlife Conservation CommissionWest Palm BeachFloridaUSA
| | - Jennifer Ketterlin
- South Florida Natural Resources CenterNational Park ServiceHomesteadFloridaUSA
| | - Eric Suarez
- Florida Fish and Wildlife Conservation CommissionWest Palm BeachFloridaUSA
| | - Frank Mazzotti
- Fort Lauderdale Research and Education CenterUniversity of FloridaDavieFloridaUSA
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3
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Currylow AF, Collier MAM, Hanslowe EB, Falk BG, Cade BS, Moy SE, Grajal‐Puche A, Ridgley FN, Reed RN, Yackel Adams AA. Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA. Ecosphere 2021. [DOI: 10.1002/ecs2.3579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Andrea F. Currylow
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Michelle A. M. Collier
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Emma B. Hanslowe
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Bryan G. Falk
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Brian S. Cade
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
| | - Sarah E. Moy
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Alejandro Grajal‐Puche
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Frank N. Ridgley
- Conservation and Research Department Zoo Miami 12400 SW 152nd Street Miami Florida 33177 USA
| | - Robert N. Reed
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
| | - Amy A. Yackel Adams
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
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4
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Goetz SM, Steen DA, Miller MA, Guyer C, Kottwitz J, Roberts JF, Blankenship E, Pearson PR, Warner DA, Reed RN. Argentine Black and White Tegu (Salvator merianae) can survive the winter under semi-natural conditions well beyond their current invasive range. PLoS One 2021; 16:e0245877. [PMID: 33690637 PMCID: PMC7946314 DOI: 10.1371/journal.pone.0245877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 01/09/2021] [Indexed: 11/19/2022] Open
Abstract
The Argentine Black and White Tegu (Salvator merianae, formerly Tupinambis merianae) is a large lizard from South America. Now established and invasive in southern Florida, and it poses threats to populations of many native species. Models suggest much of the southern United States may contain suitable temperature regimes for this species, yet there is considerable uncertainty regarding either the potential for range expansion northward out of tropical and subtropical zones or the potential for the species establishing elsewhere following additional independent introductions. We evaluated survival, body temperature, duration and timing of winter dormancy, and health of wild-caught tegus from southern Florida held in semi-natural enclosures for over a year in Auburn, Alabama (> 900 km northwest of capture location). Nine of twelve lizards emerged from winter dormancy and seven survived the greater-than-one-year duration of the study. Average length of dormancy (176 d) was greater than that reported in the native range or for invasive populations in southern Florida and females remained dormant longer than males. Tegus grew rapidly throughout the study and the presence of sperm in the testes of males and previtellogenic or early vitellogenic follicles in female ovaries at the end of our study suggest the animals would have been capable of reproduction the following spring. The survival and overall health of the majority of adult tegus in our study suggests weather and climate patterns are unlikely to prevent survival following introduction in many areas of the United States far from their current invasive range.
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Affiliation(s)
- Scott M. Goetz
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America
- * E-mail:
| | - David A. Steen
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, United States of America
| | - Melissa A. Miller
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Craig Guyer
- Department of Biological Sciences, College of Sciences and Mathematics, Auburn University, Auburn, Alabama, United States of America
| | - Jack Kottwitz
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - John F. Roberts
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Emmett Blankenship
- All Pets Emergency and Referral Center, Alpharetta, Georgia, United States of America
| | - Phillip R. Pearson
- Centre for Conservation, Ecology, and Genetics, Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital City, Australia
| | - Daniel A. Warner
- Department of Biological Sciences, College of Sciences and Mathematics, Auburn University, Auburn, Alabama, United States of America
| | - Robert N. Reed
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America
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5
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Ramiro CN, Martín J, da Silva Junior PI, Pinto HBA, Magalhães Júnior AJC, Abrahão C, Rodrigues MT. Chemical characterization of the lipids in femoral gland secretions of wild male tegu lizards, Salvator merianae (Squamata, Teiidae) in comparison with captive-bred males. Z NATURFORSCH C 2020; 75:443-449. [PMID: 32598329 DOI: 10.1515/znc-2020-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/01/2020] [Indexed: 11/15/2022]
Abstract
Although chemical interactions play an essential role in lizard social behavior, the chemical composition of the femoral gland secretions that many lizards use for communication is known for only a few species, mainly European Lacertids. The tegu lizard, Salvator merianae, is the only species of the Teiidae family for which there is available information on lipids in femoral secretions, but only for captive bred males from Argentina. Here, based on mass spectra obtained by GC-MS, we found 69 lipophilic compounds in femoral gland secretions of wild males S. merianae from Brazil, including cholesterol and high amounts of saturated fatty acids (mainly hexadecanoic and octadecanoic). We found contrasting differences between wild and captive-bred males, which lack cholesterol but present high amount of 9,12-octadecadienoic acid. These within-species differences between wild and captive lizards strongly suggest the important influence of different diets on the chemical composition of the femoral gland secretion and suggest caution when interpreting results from captive animals, even in the same species.
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Affiliation(s)
- Carolina N Ramiro
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, 05508-090, Brazil
| | - José Martín
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, Madrid, 28006, Spain
| | | | - Hugo B A Pinto
- Centro Nacional de Pesquisa e Conservação de Répteis e Anfíbios, Instituto Chico Mendes de Conservação e Biodiversidade, Goiânia, Goiás, 74605-090, Brazil
| | - Arnaldo José C Magalhães Júnior
- Colegiado Acadêmico de Ciências da Natureza, Universidade Federal do Vale do São Francisco, São Raimundo Nonato, Piauí, 64770-000, Brazil
| | - Carlos Abrahão
- Centro Nacional de Pesquisa e Conservação de Répteis e Anfíbios, Instituto Chico Mendes de Conservação e Biodiversidade, Goiânia, Goiás, 74605-090, Brazil
| | - Miguel T Rodrigues
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, 05508-090, Brazil
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Haro D, McBrayer LD, Jensen JB, Gillis JM, Bonewell LR, Nafus MG, Greiman SE, Reed RN, Yackel Adams AA. Evidence for an Established Population of Tegu Lizards (Salvator merianae) in Southeastern Georgia, USA. SOUTHEAST NAT 2020. [DOI: 10.1656/058.019.0404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Daniel Haro
- Georgia Southern University, Department of Biology, 4324 Old Register Road, Statesboro, GA 30458
| | - Lance D. McBrayer
- Georgia Southern University, Department of Biology, 4324 Old Register Road, Statesboro, GA 30458
| | - John B. Jensen
- Conservation Matters, LLC, P.O. Box 662, Monticello, GA 31064
| | - James M. Gillis
- Georgia Department of Natural Resources, Wildlife Resources Division, 1773-A Bowens Mill Hwy, Fitzgerald, GA 31750
| | - Lea' R. Bonewell
- US Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526
| | - Melia G. Nafus
- US Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526
| | - Stephen E. Greiman
- Georgia Southern University, Department of Biology, 4324 Old Register Road, Statesboro, GA 30458
| | - Robert N. Reed
- US Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526
| | - Amy A. Yackel Adams
- US Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526
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