Ecological Plasticity and the Future of the Argentine Giant Tegu (Salvator merianae Dumeril and Bibron, 1839) in the Southeastern US

Meshaka, Walter E.; Mazzotti, Frank J.; Rochford, Michael R.

doi:10.1656/058.018.0417

Cited by 8 publications

(24 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…State and federal partners collectively work to control spatially patchy populations of breeding tegus in southern Florida across three management areas (to the west, central/south, and east of the initial point of invasion) through systematic removal trapping programs. As of December 2018, over 6000 individuals were removed from these management areas in total (Meshaka et al, 2019). These removal time series in each management area provide a source of empirical monitoring data to monitor tegu population trends, evaluate the effectiveness of management, and support future decision making.…”

Section: Introductionmentioning

confidence: 99%

Open removal models with temporary emigration and population dynamics to inform invasive animal management

Udell

Martin

Romagosa

et al. 2022

Ecology and Evolution

View full text Add to dashboard Cite

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 robustdesign 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).

show abstract

Section: Introductionmentioning

confidence: 99%

Open removal models with temporary emigration and population dynamics to inform invasive animal management

Udell

Martin

Romagosa

et al. 2022

Ecology and Evolution

View full text Add to dashboard Cite

show abstract

“…Tegu reproduction typically occurs just after emergence from dormancy, but upon egress from refugia boxes our study animals were either at or slightly below minimum size estimates for sexual maturity [ 26 , 43 ], indicating they may have been too small to breed. It is also possible that we waited too long following emergence to pair males with females.…”

Section: Discussionmentioning

confidence: 86%

“…The 12 largest individuals that provided an adequate sample of each sex (8 males, 4 females) were selected for this study to allow investigation of sex effects and reproduction following hibernation. However, only one male was sexually mature at time of capture and all other individuals were slightly below minimum size estimates for sexual maturity of the Argentine Black and White Tegu and the closely related Red Tegu ( Salvator rufescens ) [ 26 , 43 ]. At time of capture, females had an average mass of 647.0 ± 33.0 g (mean ± 1 SE; range = 590–734 g) and an average snout-vent length (SVL) of 279.3 mm (mean; range = 270–295 mm; exact length data not available for one female but SVL was within stated range) and males had an average mass of 1,047.8 ± 244.3 g (range = 610–2720 g) and an average SVL of 299.1 ± 13.8 mm (range = 270–392 mm).…”

Section: Methodsmentioning

confidence: 99%

“…Thus, tegus have twice successfully established populations in Florida where they pose a threat to native and imperiled species [ 24 , 25 ]. Active control efforts are underway and over 3,300 tegus have been removed from Miami-Dade County in the past ten years [ 26 ], but tremendous effort is likely needed to achieve significant reductions in the population [ 27 ]. Population resilience in the face of removal efforts is unsurprising given tegu populations in their native range have historically withstood substantial harvests for the leather trade [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Argentine Black and White Tegu (Salvator merianae) can survive the winter under semi-natural conditions well beyond their current invasive range

et al. 2021

View full text Add to dashboard Cite

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.

show abstract

“…Tegus are omnivorous habitat generalists that have quickly established populations in natural, urban, and agricultural areas of southern Florida and now threaten the persistence of native ground-dwelling and groundnesting vertebrate populations (Barraco 2015. They are prolific breeders (Pernas et al 2012, Meshaka et al 2019, and intensive ongoing harvest in the native range for the skin trade appears to be sustainable (Fitzgerald et al 1991, Fitzgerald 1994. This suggests that control in an introduced range will prove challenging.…”

Section: Introductionmentioning

confidence: 99%

Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA

et al. 2021

View full text Add to dashboard Cite

Invasive species globally threaten biodiversity and economies, but the ecophysiological mechanisms underlying their success are often understudied. For those alien species that also exhibit high phenotypic plasticity, such as habitat generalists, adaptations in response to environmental pressures can take place relatively quickly. The Argentine giant tegu (Salvator merianae; tegu) is a large omnivorous lizard from South America that is prolific, long-lived, vagile, and highly adaptable to disturbed environments. They are well suited to the climate of southeastern United States, introduced to several disjunct areas, including the Everglades, where their voracious appetite threatens native wildlife. Tegus undergo winter dormancy (hibernation) to cope with colder temperatures, and while this behavior may facilitate invasion into more temperate regions, it may also present management opportunities. We studied the thermal habits of wild S. merianae within their invaded range in southern Florida, USA. We used radiotelemetry and trail cameras to verify aboveground behaviors, and temperature dataloggers to monitor surface (sunexposed [T e ] and shaded [T s ]), ambient (T a ), subsurface ground (T h ), and internal body (T b ) temperatures of a population of free-ranging tegus over several seasons. We evaluated thermal and behavioral data and identified five biologically significant periods: pre-hibernal, hibernal, cold snaps, hibernal-basking, and post-hibernal. We found tegus maintained thermal stability throughout the hibernal period, frequently at temperatures above available thermal microhabitats. Variation in T b was lowest during hibernation and cold snaps and was less variable than subsurface temperatures despite not leaving their hibernaculum. Hibernal ingress and egress were best predicted by temperature differentials between exposed soil and ambient daily mean temperatures (T e À T a ) and daylength. Though we detected no sex differences, larger animals started hibernation sooner, stayed in hibernation longer, and retained higher fat stores over the study period. One individual did not hibernate, representing only the second record of this behavior. Despite limitations of these descriptive data, this is the first study finely detailing T b of a population of wild, free-ranging S. merianae over multiple biologically significant time periods and to associate T b with thermal habitats within its invasive range. Tegus' apparent ability for thermal stability expands the adaptability breadth of this species and underscores the invasion threat.

show abstract

Ecological Plasticity and the Future of the Argentine Giant Tegu (Salvator merianae Dumeril and Bibron, 1839) in the Southeastern US

Cited by 8 publications

References 12 publications

Open removal models with temporary emigration and population dynamics to inform invasive animal management

Open removal models with temporary emigration and population dynamics to inform invasive animal management

Argentine Black and White Tegu (Salvator merianae) can survive the winter under semi-natural conditions well beyond their current invasive range

Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA

Contact Info

Product

Resources

About