The Panama City crayfish (Procambarus econfinae) (PCC) is a semi-terrestrial crayfish that inhabits wet pine flatwoods and prairie-marsh communities and is known to historically occur within a 56 square mile area (Figure 1). Many crayfish display physiographic integrity – restriction to a particular province or subsection, and Procambarus species are mostly Coastal Plain endemics (Butler et al. 2003), including the PCC. It is endemic to a portion of Bay County, Florida, in the vicinity of Panama City (Hobbs 1942, Mansell 1994, Keppner and Keppner 2001). This species was petitioned for federal listing under the Endangered Species Act of 1973, as amended (Act), in 2010.
The Species Status Assessment (SSA) framework (USFWS 2016) is intended to be an in-depth review of the species’ biology and threats, an evaluation of its biological status, and an assessment of the resources and conditions needed to maintain long-term viability. The intent is for the SSA Report to be easily updated as new information becomes available and to support all functions of the Endangered Species Program from Candidate Assessment, Listing, Consultations, and Recovery. As such, the SSA Report will be a living document that may be used to inform Act decision making, such as listing, recovery, Section 7, Section 10, and reclassification decisions.
Because the PCC SSA has been prepared at the 12- month petitioned finding phase, it is intended to provide the biological support for the decision on whether to propose to list the species as threatened or endangered and, if so, to determine whether it is prudent to designate critical habitat. Importantly, the SSA Report is not a decision document by the U.S. Fish and Wildlife Service (Service); rather it provides a review of available information strictly related to the biological status of the PCC. The listing decision will be made by the Service after reviewing this document and all relevant laws, regulations, and policies, and the results of a proposed decision will be announced in the Federal Register with appropriate opportunities for public input.
For the purpose of this assessment, we define viability as the ability of the species to sustain resilient populations in open pine flatwood ecosystems for at least 50 years. We chose 50 years, which encompasses 25-33 generations of the short-lived PCC and is within the range of the available human population growth (expansion into crayfish habitats) and sea level rise model forecasts. Using the SSA framework, we consider what the species needs to maintain viability by characterizing the status of the species in terms of its redundancy, representation, and resiliency (USFWS 2016; Wolf et al. 2015).
- Resiliency is assessed at the population level and reflects a species’ ability to withstand stochastic events (events arising from random factors). Generally, demographic measures that reflect population health, such as fecundity, survival, and population size, are the metrics used to evaluate resiliency. Resilient populations are better able to withstand disturbances such as random fluctuations in birth rates (demographic stochasticity), variations in rainfall (environmental stochasticity), and the effects of anthropogenic activities (timber harvest, mosquito spraying).
- Representation is assessed at the species’ level and characterizes the ability of a species to adapt to changing environmental conditions. Metrics that speak to a species’ adaptive potential, such as genetic and ecological variability, can be used to assess representation. Representation is directly correlated to a species’ ability to adapt to changes (natural or human-caused) in its environment.
- Redundancy is also assessed at the level of the species and reflects a species’ ability to withstand catastrophic events (such as a rare destructive natural event or episode involving many populations). Redundancy is about spreading the risk of such an event across multiple, resilient populations. As such, redundancy can be measured by the number and distribution of resilient populations across the range of the species.
To evaluate the current and future viability of the PCC, we assessed a range of conditions to characterize the species’ resiliency, representation, and redundancy (together, the 3Rs). This SSA Report provides an account of known biology and natural history and assesses the risk of threats and limiting factors predicted to affect the future viability of the species.
This SSA Report includes: a description of PCC resource needs at both individual and population levels; a characterization of the historic and current distribution of populations across the species’ range; an assessment of the factors that contributed to the current and future status of the species; the degree to which various factors influenced viability; and a synopsis of the factors characterized in earlier chapters as a means of examining the future biological status of the species. This document is a compilation of the best available scientific and commercial information (and associated uncertainties regarding that information) used to assess the viability of the PCC.