Crocodilians are the sole surviving reptilian archosaurs of an ancient phylogenetic lineage, evolving into the keystone and apex predators of their habitat within the tropics and sub-tropics. Unlike other reptiles, crocodilians have a four-chambered heart, and are capable of a rapid innate and anamnestic immune response as a result of a robust complement system eradicating various viruses and bacteria. This is beneficial as crocodilians are more likely to be pre-exposed to pathogens as a result of conspecific inflicted injuries in parallel with their preferred (bacteria-infested) habitat . However, climate change, habitat loss, and increasing environmental pollution can intensify susceptibility to pathogens as a result of external factors impairing immune function. Therefore it is pertinent to create a foundation of information on the relationship of host and pathogen in order to prevent epidemic host mortality and/or morbidity due to environmental alterations negatively affecting the dynamic.
The complex interaction and fundamental dependence parasites have with their host and environment are two significant factors that designate them as key biological indicators of environmental disturbance. Siddall et al. (1994) and Marcogliese and Cone (1996) discovered that studying the prevalence of digene cercariae and miracidiae in an area affected by increase sewadge sludge and water acidity was more effective in determining the negative impact on the ecosystem than assessing intermediate host abundance. In addition, the higher heavy metal accumulation and extreme concentration difference by helminth parasites in comparison to their host make them superior bio-indicators of heavy pollutants in the geographic area of study, which allows investigators to determine the cause of a negative factor that was otherwise detectable in a host or environment. Exploring the consequences of ecosystem perturbation, habitat alteration, and pollution on the symbiotic relationship between hosts and its parasites can provide the information needed to protect the productivity and biodiversity of an ecosystem. In particular, such information can be highly beneficial in protecting keystone predators of a locality that are under environmental and anthropogenic pressure.
Continual stress to survive in a rapidly changing habitat with decreased or changing resources is negatively affecting crocodilian physiology and immunity, enhancing susceptibility to parasites. This may have serious consequences as the disruption of a potentially coevolved relationship can lead to disease dispersal, irregular host population fluctuations, and parasitism of feeble hosts. This cascade of events has resulted in epidemic mortality of crocodilian species in the past, pushing many to the brink of extinction. In order to take the proper action to ensure future existence of the crocodilian species, it is essential that information be gathered on the interaction of this host-parasite system.
Crocodilian parasites have been well-documented since the early 1800s, but few have attempted to understand the unique, and possibly prehistoric, association between crocodilians and their parasites. Investigating the dynamic between crocodilians and their parasites proposes new insight on coevolution, parasite roles’ in food webs, parasite adaptations, and parasite ecology. My PhD research entailed: 1) Looking at the Spatio-Temporal dynamic of alligators and their parasites over a three year period. This could indicate which anthropogenic and environmental perturbations may alter the system. 2) Analyzing and comparing and contrasting infracommunities (parasites within the host) to component communities (host population of parasites). This could give us information on the correlation of ontogeny to parasitism, as well as heavy metals and innate immune function. 3) Compare and Contrast Florida and Louisiana alligators. And finally 4) create a niche model to predict parasite species distribution.
As a National Science Foundation Postdoctoral Fellow, I am now investigating the health and biodiversity of wildlife within crocodilian habitat in Belize.
As a result of ecological perturbations, knowledge on the significance of crocodiliasn and their parasites is necessary to take the proper action for conservation of crocodilians, their environment, and adjacent species as their preservation will have a beneficial umbrella effect due to their role as keystone predators. In addition, this can provide the necessary data for human populations that depend on crocodilians for cultural and economic growth and stability.