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Amanda Marie Kissel

Publications and source records attributed to Amanda Marie Kissel.

14 recordsLinked to original sources
USGS2026

Disease, drought, and warming: A triple threat to a declining high-elevation amphibian

Managing species in an uncertain future is a reality for natural resource decision makers. Climate change is expected to exacerbate threats such as habitat loss and disease, and cause phenological mismatches, but there is uncertainty in the magnitude of these effects. Amphibians are among the most threatened taxa on earth, and most species in North America are uniquely tied to water availability for breeding, larval development, thermal refugia, and food availability. Changes in water availability and temperature may result in phenological mismatches with one or more of these processes. Thus, quantifying the dependency of amphibians to water on the landscape is critical to understanding how species may respond, as well as understanding the interplay with other threats, such as disease. We developed a dynamic co-occurrence occupancy model to explore the effects of climate change on the breeding occurrence of boreal toads ( Anaxyrus boreas ) and the amphibian chytrid fungus ( Batrachochytrium dendrobatidis , Bd) in the southern Rocky Mountains (SRM). We derived novel covariates to test hypotheses related to multi-generational impacts of climate on the dynamics of both boreal toad breeding and Bd. We report estimates of current (2001–2019) and future (2055–2069) occupancy under a range of plausible climate scenarios. The probability of boreal toad breeding occurrence at a site in the SRM declined > 40% from 2001 to 2019, and further declines are likely under future scenarios, particularly as active season length increases. To help integrate this information into management, we developed a web-based decision support tool to summarize predicted future hydrological and occupancy conditions.

Colorado, New Mexico, Wyoming↗
USGS2026

Demographic responses to experimental manipulation of an enclosed population of invasive brown treesnakes (Boiga irregularis)

Understanding how invasive species populations respond to perturbations can give insight into effective management. However, opportunities to test theoretical population responses are rare, as experimental perturbations often run counter to management goals (e.g., suppression). On the island of Guam, a 5-ha outdoor enclosure (with no immigration or emigration) constructed in 2003 serves as a unique population-scale study area for invasive brown treesnakes ( Boiga irregularis ). Capture-mark-recapture studies (CMR) and several experiments have taken place since 2004. Here, we analyze a subset of the CMR data collected between 2008 and 2012, a time period encompassing two experimental perturbations: (1) supplemental feeding to determine if the population is food limited and (2) targeted removal of adult and large-subadult cohorts to quantify the timing and magnitude of the population's demographic response to a simulated control effort. We used the CMR data to fit a Pradel model in a Bayesian framework to compare the population growth rate, survival probability, and recruitment rate prior to, during, and post perturbations. We found that increasing food resources increased population growth and recruitment rates, but that survival remained relatively constant. The removal perturbation resulted in a decrease in population growth rate and survival immediately after the removal, but population growth rate and recruitment began increasing 1 year after the removal perturbation. Our results suggest that brown treesnakes in the enclosed population are prey limited, likely constraining population growth, and that the suppression of population growth after removal of adults and large sub-adults is short-lived (i.e., less than a year).

Guam↗
USGS2026

Case report: Observations on expulsions from 20 years of radiotransmitter implantation in adult Burmese pythons

Background Radiotelemetry as a research tool has advanced our understanding of snake behavior and ecology. However, surgical transmitter implantation can lead to health complications for study animals, including expulsion, which may also interfere with research objectives. Two implantation methods include intramuscular and coelomic placements, and we evaluate expulsion rates of transmitters using these methods in Burmese pythons ( Python bivittatus ) in southern Florida. Results From 2005 to 2024, we implanted 305 transmitters in 142 adult Burmese pythons, primarily using intramuscular implantation ( n = 221), then transitioning to include coelomic placement ( n = 84). There were no observations of transmitter-related mortality. Overall, 98.7% of transmitters were retained, with a 1.3% expulsion rate ( n = 4 transmitters). Expelled transmitters were only observed in intramuscularly implanted transmitters from 4 of 13 gravid females. Conclusions We observed no mortality related to transmitter implantation and few instances of transmitter expulsion, indicating that both intramuscular and coelomic implantation techniques are effective for monitoring adult pythons in the wild. However, there is some risk that females may expel transmitters when gravid, and this risk may be reduced when implanting transmitters intracoelomically. Our findings may be useful for studies of other large-bodied snake populations worldwide where radiotransmitter implantation is appropriate and logistically feasible.

Florida↗
USGS2026

Efficacy of increased visual and olfactory cues for luring and trapping invasive tegu lizards

Controlling invasive wildlife species relies on the ability to efficiently remove individuals from the invaded environment. Thus, maximizing capture potential is of high interest, particularly for species that are difficult to capture. For invasive species such as the Argentine black and white tegu lizard ( Salvator merianae ), increasing attraction to traps could increase the probability of removal. While it has been established that S. merianae can be lured with a single chicken egg, the efficacy of increasing olfactory or visual cues to increase tegu captures has not been rigorously tested. To test this, we leveraged an ongoing National Park Service trapping effort near Everglades National Park. In 2023 and 2024, we randomly assigned traps to a control treatment (single real egg), increased olfactory and visual treatment (three real eggs), an increased visual plus standard olfactory treatment (one real egg and one decoy egg, or one real egg and two decoy eggs), or visual treatment only (three decoy eggs). We fitted Bayesian binomial models for tegu lizards and non-target species to the trapping data to assess how bait treatment, trap style, and trap location affected the daily probability of capture at a trap. Additionally, we fitted Bayesian linear models to test the effect of bait treatment on the size of tegus captured. We found that increasing the olfactory cue to three real eggs increased the probability of tegu capture, but not the probability of non-target species capture. Conversely, traps with one real egg and two decoy eggs increased the probability of non-target captures while reducing the probability of tegu captures. Trap style and trap location also had statistically significant effects. Bait treatment did not significantly influence the size of tegus captured; however, there was a weak effect suggesting juvenile and male tegus captured in traps with three real eggs were larger compared to traps with a single egg and two decoy eggs. Our results highlight potential improvements in tegu control methods that balance effective capture with minimizing non-target bycatch.

Florida↗
USGS2025

Cold-induced vomiting of a white-tailed deer (Odocoileus virginianus) by an invasive Burmese python (Python bivitattus) in Big Cypress National Preserve, Florida, USA

The Burmese python ( Python bivittatus ) is native to Southeast Asia and has an established invasive population throughout South Florida. As part of the effort to understand invasive python biology and potential impacts to the native ecosystem, we have been using radio-telemetry to investigate feeding rates of adult female pythons. The body size and gape of adult Burmese pythons enable them to consume large native prey items including, but not limited to, white-tailed deer ( Odocoileus virginianus ). As an ectothermic species, Burmese pythons' physiological processes, including digestion, are temperature dependent, which may limit their potential invasive range. The low temperature threshold for python digestion is thought to be 20°C within a laboratory setting. Here, we detail an observation of a radio-telemetered female Burmese python that ingested an adult white-tailed deer, retained the deer within the digestive tract for 10 days, and then vomited the deer coinciding with a drop in air temperature as low as 9.4°C. The python survived the vomiting and was alive at the time of publication. To our knowledge, this is the first observation of a free-ranging Burmese python vomiting a deer within the invasive range without direct disturbance from humans at the time of vomiting. This observation provides additional evidence regarding the limits of thermal tolerance, digestion, and feeding habits of invasive Burmese pythons.

Florida↗
USGS2025

Modeling current and future distribution of invasive tegu lizards along geopolitical boundaries in the contiguous United States: Implications for invasion threat

Historically, constrained temperature ranges limited the spread of invasive herpetofauna into temperate climates, but climate change is predicted to facilitate broader distributions. There are three species of tegu lizards native to South America and available in the pet trade that have a high risk of invasion and deleterious impacts to native ecosystems in the United States (US). There are four populations of the black and white tegu ( Salvator merianae ) in Florida and sightings as far north as North Carolina and west as California. Red tegus ( S. rufescens ) have been observed in Florida, and there is an established population of gold tegus ( Tupinambis teguixin ) in Florida. We updated previous distribution models for the contiguous United States (CONUS) that used occurrence points from their native range in South America to evaluate potential changes given current and future climate scenarios (+2 °C and +4 °C warming). Under current climate conditions, one or more tegu species have the potential to occupy most ecoregions in the CONUS. Under a + 4 °C warming scenario, suitable habitat increases by 11 % for S. merianae , 31 % for S. rufescens . The proportion of suitable habitat for T. teguixin was small under all scenarios, but increased from 0.0003 to 0.0017. For S. merianae , parts of Florida become less suitable, while suitability increases in this region for the other two species. Additionally, much of the western US is projected to be suitable for S. rufescens . Our case study underscores the potential for climate change to compound invasion threats that could outpace effective managerial responses.

contiguous United States↗
USGS2025

Assessing the effects of climate and visitor use on amphibian occupancy in a protected landscape with long-term data

Determining where animals are, and if they are persisting across protected landscapes, is necessary to implement appropriate management and conservation actions. For long-lived animals and those with boom-and-bust life histories, perspective across time contributes to discerning temporal trends in occupancy and persistence, and potentially in identifying mechanisms affecting those parameters. Long-term data are particularly useful in protected areas to quantify indicators of change that may be less obvious or occur more slowly. We used long-term amphibian data from Rocky Mountain National Park (RMNP) in a Bayesian occupancy modeling framework to estimate changes in occupancy, colonization, and persistence of amphibians over three decades and to explore the effects of climate, landscape change, and visitor use as mechanisms behind observed changes. Our results indicate that colonization and persistence are low and/or declining for Pseudacris maculata , Lithobates sylvaticus , and Ambystoma mavortium , and that occupied catchments are increasingly isolated. We found visitor use to have a consistently negative effect on occupancy and persistence of amphibians in RMNP, and that all species are more likely to occupy catchments with more complex habitat and a higher proportion of wetlands. While these results are sobering, they also provide a way forward where mitigation efforts can target identified drivers of change.

Colorado↗
USGS2025

An early detection rapid response case study of the Black and White Tegu (Salvator merianae) and implications for a broader framework

Documentation of successful early detection rapid response (EDRR) efforts is lacking from the scientific literature but is needed to inform invasive species response protocols. The Black and White tegu (Salvator merianae) has become established in several Florida counties and its spread is of significant conservation concern. It is of high priority for state and federal managers to prevent the spread into sensitive ecosystems, including the Greater Everglades. Thus, coordinated EDRR efforts are essential given limited infrastructure and funding for such tasks. While tegus have been observed along the eastern boundary of Everglades National Park, there has been no evidence tegus are established within Big Cypress National Preserve. On 8 August 2024 an individual tegu was sighted by a U.S. Geological Survey (USGS) biologist in Big Cypress National Preserve who alerted National Park Service (NPS) staff and mobilized a response. Live traps were placed at the location of sighting within 24 hours and an individual tegu was captured on 13 August 2024. The individual tegu was determined to be the same individual that was observed five days early based on color, pattern, and other physical characteristics. No additional tegus were captured. The rapid, coordinated response of NPS and USGS likely contributed to this successful EDRR event, and highlights the need for more expansive EDRR frameworks at multiple jurisdictional scales.

Florida↗
USGS2025

A framework for guiding management decisions for amphibians in an uncertain future

Managing species in a rapidly changing climate requires knowledge of how species will respond to climate change and other threats while simultaneously developing management actions to reduce threats. Amphibians are one of the most threatened taxa on earth and often serve as the ‘canary in the coalmine’ for the health of ecosystems that countless other species and humans rely on. To understand the status of and guide management for the boreal toad (Anaxyrus boreas boreas), an imperiled amphibian species in the North Central region, we coproduced several products with the Boreal Toad Conservation Team. These products included 1) reconstructed seasonal hydrology patterns for historical boreal toad breeding wetlands and high elevation watersheds in the Southern Rocky Mountain Region (SRMR) from remotely sensed data, 2) current and future predictions of drying rates for historical breeding wetlands, 3) current and future predictions on the status of the boreal toad in the SRMR, and 4) a web tool to guide management actions. While the boreal toad is considered a ‘data rich’ species given data collection efforts that span multiple decades, many amphibian species are considered ‘data poor’, meaning managers lack data on the biology, ecology, or status of the species needed to make sound decisions. To address this knowledge gap, we also quantified drying patterns across watersheds for two ‘data poor’ species in the North Central region at risk from climate change: the Great Basin spadefoot toad ( Spea intermontana ) and the wood frog ( Lithobates sylvaticus ). These new data can guide management decisions for these species by allowing managers to understand habitat changes with respect to water availability, a crucial element for amphibian survival and persistence. Together, these products demonstrate how cutting-edge technology and analytical methods can produce a range of useful information to support amphibian conservation.

Colorado, New Mexico, Wyoming↗
USGS2024

Flooding-induced failure of an invasive Burmese Python nest in southern Florida

It is important to understand the factors affecting the reproductive success of an invasive species to estimate population size and develop management plans. There remains much we do not understand about the reproductive biology of invasive Burmese Pythons in both their native and invasive range. Oviposition site selection is an important factor in determining reproductive success as nesting is a vulnerable period in the life of reptiles. Flooding can be particularly influential for nesting outcomes and success of developing embryos in habitats that experience periods of heavy rainfall or seasonal flooding. It is not clear how seasonal flooding may impact oviposition site selection by females or hatchling survival of Burmese Pythons in Florida. On 10 May 2023, a radio-transmitted female python oviposited in a hollow log and during incubation all eggs were completely submerged for variable amounts of time. All eggs were collected (n = 78) and dissected to confirm fertilization and assess the stage of embryo development. Two eggs were found to be infertile, while the remaining fertile eggs contained embryos that died at various stages of development. The observed failure of this python nest was a direct result of oviposition site selection by the female. The frequency at which females lay eggs in suboptimal locations in southern Florida is currently unknown. This maladaptive behavior would suggest Burmese Pythons have fitness levels below theoretical optima.

Florida↗