An apex predator engineers wetland food-web heterogeneity through nutrient enrichment and habitat modification.

The potential for animals to modify spatial patterns of nutrient limitation for autotrophs and habitat availability for other members of their communities is increasingly recognized. However, net trophic effects of consumers acting as ecosystem engineers remain poorly known. The American Alligator Alligator mississippiensis is an abundant predator capable of dramatic modifications of physical habitat through the creation and maintenance of pond-like basins, but its role in influencing community structure and nutrient dynamics is less appreciated. We investigated if alligators engineer differences in nutrient availability and changes to community structure by their creation of 'alligator ponds' compared to the surrounding phosphorus (P)-limited oligotrophic marsh. We used a halo sampling design of three distinct habitats extending outward from 10 active alligator ponds across a hydrological gradient in the Everglades, USA. We performed nutrient analysis on basal food-web resources and quantitative community analyses, and stoichiometric analyses on plants and animals. Our findings demonstrate that alligators act as ecosystem engineers and enhance food-web heterogeneity by increasing nutrient availability, manipulating physical structure and altering algal, plant and animal communities. Flocculent detritus, an unconsolidated layer of particulate organic matter and soil, showed strong patterns of P enrichment in ponds. Higher P availability in alligator ponds also resulted in bottom-up trophic transfer of nutrients as evidenced by higher growth rates (lower N:P) for plants and aquatic consumers. Edge habitats surrounding alligator ponds contained the most diverse communities of invertebrates and plants, but low total abundance of fishes, likely driven by high densities of emergent macrophytes. Pond communities exhibited higher abundance of fish compared to edge habitat and were dominated by compositions of small invertebrates that track high nutrient availability in the water column. Marshes contained high numbers of animals that are closely tied to periphyton mats, which were absent from other habitats. Alligator-engineered habitats are ecologically important by providing nutrient-enriched 'hotspots' in an oligotrophic system, habitat heterogeneity to marshes, and refuges for other fauna during seasonal disturbances. This work adds to growing evidence that efforts to model community dynamics should routinely consider animal-mediated bottom-up processes like ecosystem engineering.

Sperm cryopreservation in the Burmese python Python bivittatus as a model for endangered snakes.

Burmese pythons Python bivittatus captured in the Florida Everglades as part of an invasive species monitoring program served as a model for the development of sperm cryopreservation protocols for endangered snakes. Spermatozoa were collected from the vas deferens and initial motility, plasma membrane integrity and acrosome integrity were recorded before cryopreservation. Spermatozoa were extended in TES and Tris (TEST) yolk buffer with glycerol (GLY) or dimethyl sulfoxide (DMSO) concentrations of 8%, 12% or 16%, or combinations of GLY and DMSO with final concentrations of 4%:4%, 6%:6% or 8%:8%, and frozen at a rate of 0.3°C min-1 . Sperm frozen in combinations of GLY and DMSO exhibited greater post-thaw motility and plasma membrane integrity than those frozen in GLY or DMSO alone. All DMSO and GLY:DMSO treatments preserved a greater proportion of intact acrosomes than GLY alone. To determine the best overall cryopreservation protocol for this species, a sperm quality index was calculated, giving equal weight to each of the three measured indicators of cryosurvival. This analysis revealed that Burmese python spermatozoa frozen in 6% GLY:6% DMSO or 4% GLY:4% DMSO exhibited the highest post-thaw viability. This study represents the first comparative, comprehensive attempt to develop a sperm cryopreservation protocol for any snake species.

Shifts in hatching date of American crocodile (Crocodylus acutus) in southern Florida.

Globally temperature of marine environments is on the rise and temperature plays an important role in the life-history of reptiles. In this study, we examined the relationship between sea surface temperature and average date of hatching for American crocodiles (Crocodylus acutus) over a 37-year period at two nesting sites, Everglades National Park and Florida Power and Light Turkey Point Power Plant site in southern Florida. Our results indicate that hatch dates are shifting 1.5 days earlier every two years and at half that rate for the Turkey Point site, and with every 1 °C degree increase in temperature, hatching occurs about 10 days earlier in the Everglades and 6 days earlier at Turkey Point. Our results on shifting hatch dates for American crocodiles provide further details about the impacts of temperature change on crocodile life history and suggest that increased temperature may affect their phenology.

Novel ecological and climatic conditions drive rapid adaptation in invasive Florida Burmese pythons.

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.

Life histories and conservation of long-lived reptiles, an illustration with the American crocodile (Crocodylus acutus).

Successful species conservation is dependent on adequate estimates of population dynamics, but age-specific demographics are generally lacking for many long-lived iteroparous species such as large reptiles. Accurate demographic information allows estimation of population growth rate, as well as projection of future population sizes and quantitative analyses of fitness trade-offs involved in the evolution of life-history strategies. Here, a long-term capture-recapture study was conducted from 1978 to 2014 on the American crocodile (Crocodylus acutus) in southern Florida. Over the study period, 7,427 hatchlings were marked and 380 individuals were recaptured for as many as 25 years. We estimated survival to be strongly age dependent with hatchlings having the lowest survival rates (16%) but increasing to nearly 90% at adulthood based on mark-recapture models. More than 5% of the female population were predicted to be reproductive by age 8 years; the age-specific proportion of reproductive females steadily increased until age 18 when more than 95% of females were predicted to be reproductive. Population growth rate, estimated from a Leslie-Lefkovitch stage-class model, showed a positive annual growth rate of 4% over the study period. Using a prospective sensitivity analysis, we revealed that the adult stage, as expected, was the most critical stage for population growth rate; however, the survival of younger crocodiles before they became reproductive also had a surprisingly high elasticity. We found that variation in age-specific fecundity has very limited impact on population growth rate in American crocodiles. We used a comparative approach to show that the original life-history strategy of American crocodiles is actually shared by other large, long-lived reptiles: while adult survival rates always have a large impact on population growth, this decreases with declining increasing growth rates, in favour of a higher elasticity of the juvenile stage. Crocodiles, as a long-lived and highly fecund species, deviate from the usual association of life histories of "slow" species. Current management practices are focused on nests and hatchling survival; however, protection efforts that extend to juvenile crocodiles would be most effective for conservation of the species, especially in an ever-developing landscape.

Factors affecting individual foraging specialization and temporal diet stability across the range of a large "generalist" apex predator.

Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable isotopes. Gut contents revealed that, over the short term, although alligator populations occupied wide ranges of the INS spectrum, general patterns were apparent. Alligator populations inhabiting lakes exhibited lower INS than coastal populations, likely driven by variation in habitat type and available prey types. Stable isotopes revealed that over longer time spans alligators exhibited remarkably consistent use of variable mixtures of carbon pools (e.g., marine and freshwater food webs). We conclude that INS in large-bodied reptilian predator populations is likely affected by variation in available prey types and habitat heterogeneity, and that INS should be incorporated into management strategies to efficiently meet intended goals. Also, ecological models, which typically do not consider behavioral variability, should include INS to increase model realism and applicability.

Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park.

Invasive species represent a significant threat to global biodiversity and a substantial economic burden. Burmese pythons, giant constricting snakes native to Asia, now are found throughout much of southern Florida, including all of Everglades National Park (ENP). Pythons have increased dramatically in both abundance and geographic range since 2000 and consume a wide variety of mammals and birds. Here we report severe apparent declines in mammal populations that coincide temporally and spatially with the proliferation of pythons in ENP. Before 2000, mammals were encountered frequently during nocturnal road surveys within ENP. In contrast, road surveys totaling 56,971 km from 2003-2011 documented a 99.3% decrease in the frequency of raccoon observations, decreases of 98.9% and 87.5% for opossum and bobcat observations, respectively, and failed to detect rabbits. Road surveys also revealed that these species are more common in areas where pythons have been discovered only recently and are most abundant outside the python's current introduced range. These findings suggest that predation by pythons has resulted in dramatic declines in mammals within ENP and that introduced apex predators, such as giant constrictors, can exert significant top-down pressure on prey populations. Severe declines in easily observed and/or common mammals, such as raccoons and bobcats, bode poorly for species of conservation concern, which often are more difficult to sample and occur at lower densities.

Using scenario planning to evaluate the impacts of climate change on wildlife populations and communities in the Florida Everglades.

It is uncertain how climate change will impact hydrologic drivers of wildlife population dynamics in freshwater wetlands of the Florida Everglades, or how to accommodate this uncertainty in restoration decisions. Using projections of climate scenarios for the year 2060, we evaluated how several possible futures could affect wildlife populations (wading birds, fish, alligators, native apple snails, amphibians, threatened and invasive species) across the Everglades landscape and inform planning already underway. We used data collected from prior research and monitoring to parameterize our wildlife population models. Hydrologic data were simulated using a spatially explicit, regional-scale model. Our scenario evaluations show that expected changes in temperature, precipitation, and sea level could significantly alter important ecological functions. All of our wildlife indicators were negatively affected by scenarios with less rainfall and more evapotranspiration. Under such scenarios, habitat suitability was substantially reduced for iconic animals such as wading birds and alligators. Conversely, the increased rainfall scenario benefited aquatic prey productivity and apex predators. Cascading impacts on non-native species is speculative, but increasing temperatures could increase the time between cold events that currently limit expansion and abundance of non-native fishes, amphibians, and reptiles with natural ranges in the tropics. This scenario planning framework underscored the benefits of proceeding with Everglades restoration plans that capture and clean more freshwater with the potential to mitigate rainfall loss and postpone impacts of sea level rise.

Homing of invasive Burmese pythons in South Florida: evidence for map and compass senses in snakes.

Navigational ability is a critical component of an animal's spatial ecology and may influence the invasive potential of species. Burmese pythons (Python molurus bivittatus) are apex predators invasive to South Florida. We tracked the movements of 12 adult Burmese pythons in Everglades National Park, six of which were translocated 21-36 km from their capture locations. Translocated snakes oriented movement homeward relative to the capture location, and five of six snakes returned to within 5 km of the original capture location. Translocated snakes moved straighter and faster than control snakes and displayed movement path structure indicative of oriented movement. This study provides evidence that Burmese pythons have navigational map and compass senses and has implications for predictions of spatial spread and impacts as well as our understanding of reptile cognitive abilities.

Correction: How to estimate body condition in large lizards? Argentine black and white tegu (Salvator merianae, Duméril and Bibron, 1839) as a case study.

[This corrects the article DOI: 10.1371/journal.pone.0282093.].

Ecological implications of allometric relationships in American alligators (Alligator mississippiensis).

Morphometric allometry, the effect of size on morphological variation, has been of great interest for evolutionary biologist and is currently used in fields such as wildlife ecology to inform management and conservation. We assessed American alligator (Alligator mississippiensis) morphological static allometry across the Greater Everglades ecosystem in South Florida, United States using a robust dataset (~ 22 years) and investigated effects of sex, habitat, and sampling area on morphological relationships. Regression models showed very strong evidence of a linear relationship between variables explaining equal to or above 92% of the variation in the data. Most trait-size relationships (8 out of 11 assessed) showed hyperallometry (positive allometry) with slope deviations from isometry between 0.1 and 0.2 units while the other three relationships were isometric. Sampling area, type of habitat, and in a lesser extent sex influenced allometric coefficients (slope and intercept) across several relationships, likely as result of differing landscapes and ecosystem dynamic alterations and sexual dimorphism. We discuss our findings in terms of the biology of the species as well as the usefulness of our results in the context of ecosystem restoration and conservation of the species. Finally, we provide recommendations when using trait-length relationships to infer population nutritional-health condition and demographics.

How to estimate body condition in large lizards? Argentine black and white tegu (Salvator merianae, Duméril and Bibron, 1839) as a case study.

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.

Body condition as a descriptor of American alligator (Alligator mississippiensis) health status in the Greater Everglades, Florida, United States.

Body condition is used as an indicator of the degree of body fat in an animal but evidence of its actual relationship with health diagnostics (e.g., blood parameters) is usually lacking across species. In American alligators (Alligator mississippiensis), body condition has been used as a performance metric within the Greater Everglades ecosystem to provide insight on hydrological and landscape changes on alligator populations. However, there is no clear evidence that spatial body condition changes relate to different health conditions (low food intake vs sickness) and whether this link can be made when relating body condition values with blood parameters. We assessed the relationship between alligator body condition and 36 hematological and biochemistry (blood) parameters in four areas across two physiographic regions (Everglades and Big Cypress) of the Greater Everglades (sample size = 120). We found very strong to weak evidence of linearity between 7 (Big Cypress) and 19 (Everglades) blood parameters and relative condition factor index, from which cholesterol (38%) and uric acid (41%) for the former and phosphorus (up to 52%) and cholesterol (up to 45%) for the latter (mean absolute error MAE = 0.18 each) were the predictors that individually explain most of the body condition variation. The best combination of blood parameters for the Everglades were cholesterol, phosphorus, osmolality, total protein, albumin, alpha 2, beta, and gamma globulins, and corticosterone accounting for 40% (37 ± 21%, MAE = 0.16) of the variation found in alligator body condition for this region. We found better predictability power in models when analyzed at smaller rather than larger scales showing a potential habitat effect on the body condition-blood parameters relationship. Overall, Everglades alligators in poorer condition are likely dehydrated or have an inadequate diet and the spatial differences found between physiographic regions suggest that these areas differ in prey availability/quality.

Population assessment of the American crocodile, Crocodylus acutus (Crocodilia: Crocodylidae) on the Pacific coast of Costa Rica.

The American crocodile, Crocodylus acutus, is widely distributed in the American neotropics. It is endangered throughout most of its range and is listed as vulnerable by the International Union for the Conservation of Natural Fauna and Flora (IUCN) and on Appendix I of the Convention for the International Trade in Endangered Species of Wild Flora and Fauna (CITES). Despite this listing, there are few published reports on population status throughout most of its range. We investigated the status of the C. acutus, at several locations along the Pacific coast of Costa Rica. We carried out spotlight and nesting surveys from 2007-2009 along the Costa Rican Pacific coast in four distinct areas, coastal areas of Las Baulas (N=40) and Santa Rosa (N=9) National Parks and the Osa Conservation Area (N=13), and upriver in Palo Verde National Park (N=11). We recorded crocodile locations and standard environmental data at each observation. Encounter rates, population structure, distribution within each area and data on successful nesting (presence of hatchlings, nests, etc) were determined. We attempted to capture all crocodiles to record standard morphometrics. A total of 586 crocodiles were observed along 185.8km of survey route. The majority of animals encountered (54.9%) were either hatchlings (<0.5m) or juveniles (0.5-1.25m). The average non-hatchling encounter rate per survey for the Pacific coast was 3.1 crocodiles/km, with individual encounter rates ranging from 1.2 crocodiles/km to 4.3 crocodiles/ km in Las Baulas National Park and the Osa Conservation Area respectively. Distribution of size classes within the individual locations did not differ with the exception of Santa Rosa and Las Baulas National Parks, where hatchlings were found in water with lower salinities. These were the first systematic surveys in several of the areas studied and additional work is needed to further characterize the American crocodile population in Costa Rica.

Trophic State Drives the Diversity of Protists in a Tropical River (New River, Belize).

Land use disrupts the ecosystem functioning of freshwater systems and significantly affects trophic state. Consequently, biodiversity is severely affected by changes to the ecosystem. Microbial eukaryotes (i.e., protists) play an essential role in ecosystem functioning, contributing to biogeochemical processes, nutrient cycling, and food webs. Protist composition is a useful biological quality parameter for monitoring aquatic ecosystems and determining aquatic system health. In this study, we investigated the effects of land usage and trophic state on the communities of microbial eukaryotes in the New River (Belize, C.A.). Land use and trophic state both significantly affected protist community compositions, with impacted and mesotrophic sampled sites having higher biodiversity when compared to other sites. Autotrophic organisms dominated indirectly impacted and eutrophic sites, while impacted and mesotrophic sites had proportional ratios of autotrophic and heterotrophic organisms. Our study highlights the significant effects of trophic gradients on protistan community composition, even at the local scales.

Hematology and biochemistry reference intervals for American crocodiles (Crocodylus acutus) in South Florida.

The American crocodile (Crocodylus acutus) is considered a vulnerable species by the International Union for Conservation of Nature (IUCN) Red List across its range and classified as locally threatened in several countries. There is a lack of knowledge involving hematological and physiological parameters in American crocodile populations, limiting our understanding of what are considered "normal" blood analyte results for the species and how to link them with health assessments. In this study, we analyzed 40 hematological and biochemical parameters and estimated reference intervals (RIs) for 35 of them based on 436 clinically healthy wild American crocodiles caught in South Florida between 2015 and 2021. Crocodiles were captured across three areas with different levels of human influence [low = Everglades National Park (ENP), medium = Biscayne Bay Estuary (BBE), and high = Turkey Point Nuclear Power Plant (TP)]. There was very strong-to-strong evidence for an effect of where animals were caught on five analytes: basophils %, phosphorus, proportion of (pr) alpha-2 globulins, absolute count (abs) of gamma globulins, and corticosterone, so no reference values were estimated but general statistics are presented and discussed. From the remaining analytes, we found no evidence that sex or size class had an effect on red blood cell (RBC), azurophils and monocytes abs, triglycerides, and albumin abs. However, we did find moderate-to-strong evidence that sex influenced azurophils % and size class influenced white blood cell (WBC), heterophils %, monocytes %, basophils abs, creatine phosphokinase (CPK), potassium, glucose, bile acids, alpha-1 globulin abs, and alpha-2 globulin pr and abs. Finally, there was strong evidence that both sex and size class influenced PCV, lymphocytes % and abs, eosinophils % and abs, aspartate aminotransferase (AST), calcium, sodium, chloride, total protein, albumin/globulin (A/G) ratio, albumin pr, alpha-1 globulin, and beta globulin abs. Intraspecific analysis showed that size is the variable that most influenced analytes explaining up to 29% of the variation, which relates to our findings based on intraindividual analysis. We compared our results with blood parameters reported for conspecifics as well as closely related species and discussed implication of those results for clinical diagnosis and American crocodile conservation.

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

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).

Hematology and Biochemistry Reference Intervals for American Alligator (Alligator mississippiensis) in South Florida, USA.

We calculated reference intervals for 48 blood parameters from 120 wild American alligators (Alligator mississippiensis) in South Florida, US. Although previously reported by others, this study includes additional parameters not yet reported in wild populations. Most previously reported blood parameter values were similar to ours and fell within our reference intervals.

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity.

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.

American crocodiles (Crocodylus acutus) as restoration bioindicators in the Florida Everglades.

The federally threatened American crocodile (Crocodylus acutus) is a flagship species and ecological indicator of hydrologic restoration in the Florida Everglades. We conducted a long-term capture-recapture study on the South Florida population of American crocodiles from 1978 to 2015 to evaluate the effects of restoration efforts to more historic hydrologic conditions. The study produced 10,040 crocodile capture events of 9,865 individuals and more than 90% of captures were of hatchlings. Body condition and growth rates of crocodiles were highly age-structured with younger crocodiles presenting with the poorest body condition and highest growth rates. Mean crocodile body condition in this study was 2.14±0.35 SD across the South Florida population. Crocodiles exposed to hypersaline conditions (> 40 psu) during the dry season maintained lower body condition scores and reduced growth rate by 13% after one year, by 24% after five years, and by 29% after ten years. Estimated hatchling survival for the South Florida population was 25% increasing with ontogeny and reaching near 90% survival at year six. Hatchling survival was 34% in NE Florida Bay relative to a 69% hatchling survival at Crocodile Lake National Wildlife Refuge and 53% in Flamingo area of Everglades National Park. Hypersaline conditions negatively affected survival, growth and body condition and was most pronounced in NE Florida Bay, where the hydrologic conditions have been most disturbed. The American crocodile, a long-lived animal, with relatively slow growth rate provides an excellent model system to measure the effects of altered hydropatterns in the Everglades landscape. These results illustrate the need for continued long-term monitoring to assess system-wide restoration outcomes and inform resource managers.