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Spectacled caimans (Caiman crocodilus Linnaeus, 1758) are established invaders in the United States, Cuba, and San Andres Island, Colombia. They have been established in South Florida since the 1970s and are found primarily within Comprehensive Everglades Restoration Plan (CERP) projects. These projects provide suitable habitat and may provide dispersal pathways via water management activities. Caiman presence in these areas directly conflicts with the CERP’s goals, and as a generalist species with a broad diet, they can impact biological resources. Past removal efforts failed to extirpate caimans, but their efficacy has not been well evaluated. We addressed caimans via removal surveys during 2012–2021 with the goal of evaluating extirpation or maximum species control within South Florida’s CERP projects. Documented opportunistic removals for this study began in December 2012, and systematic efforts have been ongoing since October 2017. We evaluated efficacy of caiman removals by analyzing 10 years of opportunistic and systematic survey data, plus associated removal data, along 11 survey routes during 2012–2021. We also conducted necropsies to collect biological information which could be used to improve removal efforts. We removed 251 caimans during 2012 to 2021, and the rate of caiman removals per year increased from 5 animals during 2012 to a peak of 47 animals during 2020. Necropsies revealed reproductive information (nesting/hatching timelines) that we applied to improve our removal rates. Caiman encounter rates declined from a peak of 1.55 ± 0.66 caiman/hr and 0.72 ± 0.38 caiman/km during 2013 to a low of 0.18 ± 0.09 caiman/hr and 0.03 ± 0.02 caiman/km during 2020 and slightly increased during 2020–2021, likely because of a change in search effort. We evaluated and discussed the potential for extirpating caiman from CERP projects and provide a data-driven prescription for removal efforts. [ABSTRACT FROM AUTHOR]

The design of successful invasive species control programs is often hindered by the absence of basic demographic data on the targeted population. Establishment of invasive Burmese pythons (Python molurus bivittatus) in the Greater Everglades Ecosystem, Florida USA has led to local precipitous declines (> 90%) of mesomammal populations and is also a major threat to native populations of reptiles and birds. Efforts to control this species are ongoing but are hampered by the lack of access to and information on the expected biological patterns of pythons in southern Florida. We present data from more than 4,000 wild Burmese pythons that were removed in southern Florida over 26 years (1995-2021), the most robust dataset representing this invasive population to date. We used these data to characterize Burmese python size distribution, size at maturity, clutch size, and seasonal demographic and reproductive trends. We broadened the previously described size ranges by sex and, based on our newly defined size-stage classes, showed that males are smaller than females at sexual maturity, confirmed a positive correlation between maternal body size and potential clutch size, and developed predictive equations to facilitate demographic predictions. We also refined the annual breeding season (approx.100 days December into March), oviposition timing (May), and hatchling emergence and dispersal period (July through October) using correlations of capture morphometrics with observations of seasonal gonadal recrudescence (resurgence) and regression. Determination of reproductive output and timing can inform population models and help managers arrest population growth by targeting key aspects of python life history. These results define characteristics of the species in Florida and provide an enhanced understanding of the ecology and reproductive biology of Burmese pythons in their invasive Everglades range. [ABSTRACT FROM AUTHOR]

Golden tegus (Tupinambis teguixin sensu lato) are native to South America but have established a reproducing population in Miami-Dade County, Florida. Recent work divided the golden tegu into four distinct species, leaving the specific identity of golden tegus in Florida unknown. We used morphometric and mitochondrial data to determine the species identity and likely area of geographic origin for a specimen of golden tegu collected in Miami-Dade County. Our results confirm that cryptic golden tegus (Tupinambis cryptus) are at least one of the species established in Florida. Their geographic origin is likely mainland Guyana or Venezuela. The presence of T. teguixin in Florida remains possible, based on other specimens of ambiguous scalation. Further study is needed to determine the identity and origin of these populations. [ABSTRACT FROM AUTHOR]

Invasive species provide powerful in situ experimental systems for studying evolution in response to selective pressures in novel habitats. While research has shown that phenotypic evolution can occur rapidly in nature, few examples exist of genomewide adaptation on short "ecological" timescales. Burmese pythons (Python molurus bivittatus) have become a successful and impactful invasive species in Florida over the last 30 years despite major freeze events that caused high python mortality. We sampled Florida Burmese pythons before and after a major freeze event in 2010 and found evidence for directional selection in genomic regions enriched for genes associated with thermosensation, behaviour and physiology. Several of these genes are linked to regenerative organ growth, an adaptive response that modulates organ size and function with feeding and fasting in pythons. Independent histological and functional genomic data sets provide additional layers of support for a contemporary shift in invasive Burmese python physiology. In the Florida population, a shift towards maintaining an active digestive system may be driven by the fitness benefits of maintaining higher metabolic rates and body temperature during freeze events. Our results suggest that a synergistic interaction between ecological and climatic selection pressures has driven adaptation in Florida Burmese pythons, demonstrating the often‐overlooked potential of rapid adaptation to influence the success of invasive species. [ABSTRACT FROM AUTHOR]

Gold tegus, Tupinambis teguixin (Linnaeus, 1758), are generalist predators from South America and are ecologically similar to Argentine black and white tegus (Salvator merianae), a successful invader in Florida. We trapped gold tegus in Broward and Miami-Dade counties, Florida, USA. In Miami-Dade County, collection occurred from 2008 through 2016. We combined new trapping records with previous literature records. Ten gold tegus of both sexes and multiple size classes over a nine year period indicate a reproducing population in Miami-Dade County. Tupinambis teguixin is the sixth established non-native teiid species in Florida. Additionally, we report Tupinambis teguixin from Sarasota and Lee counties, Florida, USA. Determining population status in those counties requires further study. It is critical to differentiate this species from Salvator merianae during removal efforts. The possibility of eradicating Tupinambis teguixin exists if proper identification enables reliable monitoring of the populations. [ABSTRACT FROM AUTHOR]

The article focuses on the diet and predation of Masticophis flagellum (Coachwhip) and Heterodon nasicus (Western Hog-nosed Snake), highlighting the various species that M. flagellum has been known to prey upon, as well as a newly reported case of H. nasicus being depredated by M. flagellum.

The article focuses on the American crocodile (Crocodylus acutus) captured during a crocodile spotlight survey of East Cape Canal, Everglades National Park (ENP) on December 15, 2008. The author says that the C. acutus with 416.7 cm total length (TL) was a large male crocodile with a distinct scute slip #225. Meanwhile, the crocodile #225 was first caught on August 9, 1986 in the Flamingo Boat Basin, ENP, representing the largest live capture of C. acutus in Florida. It states that the next longest time interval is for a male, measuring 384.9 cm TL from the same nest as crocodile #225. Furthermore, the recaptures of two C. acutus in ENP is noted to underline the significance of the long-term monitoring programs for Endangered and Threatened species recovery.