This species status assessment (SSA) reports the results of a comprehensive status review for the Panama City crayfish (PCC) (Procambarus econfinae), documenting the species historical conditions and providing estimates of current and future conditions under a range of different scenarios. The PCC is only known from a small portion of Bay County, Florida, in the vicinity of Panama City (Hobbs 1942, Mansell 1994, Keppner and Keppner 2001) (Figure 1.1). Historically, the PCC inhabited natural and often temporary bodies of shallow fresh water within open pine flatwoods (Hobbs 1942) and wet prairie-marsh communities. However, most of these communities have been cleared for residential or commercial development or replaced with slash pine plantations. Thus, the PCC currently is known to inhabit the waters of grassy, gently-sloped ditches and swales, slash pine plantations, utility rights-of-way (Keppner and Keppner 2001) and a few remnant parcels protected under wetland and private easements.
The SSA process can be categorized into three sequential stages. During the first stage, we used the conservation biology principles of resiliency, redundancy, and representation (together, the 3Rs) to evaluate individual PCC life history needs. The next stage involved an assessment of the historical and current condition of the species’ demographics and habitat characteristics, including an explanation of how the species arrived at its current condition. The final stage of the SSA involved making predictions about its response to positive and negative environmental and anthropogenic influences. This process used the best available information to characterize viability as the ability of the species to sustain populations in the wild over time.
To evaluate the current and future viability of the PCC, we assessed a range of conditions to allow us to consider the species’ resiliency, representation, and redundancy. For the purposes of this assessment, populations were delineated by seemingly isolated tracts of property currently occupied.
Resiliency, assessed at the population level, describes the ability of a population to withstand stochastic disturbance events. A species needs multiple resilient populations distributed across its range to persist into the future and avoid extinction. These factors include (1) connectivity, (2) high inbreeding coefficient, and (3) sufficient and suitable habitat. The PCC will need adequate pine flatwoods and prairie-marsh habitat within core and secondary soils to survive and thrive in abundance. We discuss each of these factors. As we consider the future viability of the species, more populations with high resiliency distributed across the known range are associated with higher overall viability.
Redundancy describes the ability of the species to withstand catastrophic disturbance events; for the PCC, we considered whether the distribution a localized endemic species population was sufficient for minimizing the potential loss of the species from a catastrophic event.
Representation characterizes a species adaptive potential by assessing geographic, genetic, ecological, and niche variability. The PCC has historically occurred within a range of ~56 square miles in Bay County, Florida. The species is currently represented throughout the historic range, albeit at isolated and small populations on the western portion of the range with a much larger area of undeveloped habitat within the eastern part of its range where developmental pressures are reduced.
We have assessed the PCC’s levels of resiliency, redundancy, and representation currently and into the future by ranking the condition of each population. Rankings are quantitate assessments of the relative condition of the PCC’s remaining habitat within its known range based on the knowledge and expertise of the U.S. Fish and Wildlife Service’s and Florida Fish and Wildlife Conservation Commission’s draft management plan, reports from PCC experts, and recent genetic analysis (Duncan et al. 2017; Appendix 1) .
Together Resiliency, Redundancy, Representation, the 3R’s, comprise the key characteristics that contribute to a species’ ability to sustain multiple distinct populations in the wild over time (i.e., viability). Using the principles of the 3 R’s, we characterized both the species’ current viability and forecasted its future viability over a range of plausible future scenarios. To this end, we ranked the condition of each population by assessing the relative condition of each population using the best available scientific information.
The most significant stressor to individuals and populations of the PCC is expansion of human populations and associated residential and commercial development. Much of this development has occurred within historic flatwoods habitats and much of the remaining undeveloped habitat is now largely in pine plantations. These plantations are currently at risk of development. Cumulative stressors include changes in weather patterns, such as droughts or altered rain patterns, that may reduce or alter breeding patterns and may have greater effects on smaller isolated populations. We also evaluated whether future climate change and sea level rise may reduce habitats currently available to the PCC. Two populations are susceptible to habitat changes due to sea level rise and may be unlikely to recover from catastrophic events. Translocations, and other population management techniques, are possible and may be necessary to sustain populations.
The PCC will experience a loss of habitat in the future, and we have forecasted what the PCC may have in terms of resiliency, redundancy, and representation under future plausible scenarios:
1) Expected human and commercial growth of the Panama City area over a span of approximately 10, 30 and 50 years (2030, 2050, and 2070); and
2) Expected human and commercial growth at three levels of intensity, status quo (>80% probability of occurrence), intermediate (>30% probability of occurrence), and high (>0% probability of occurrence).
We used the best available information to forecast the likely future condition of the PCC. Our goal was to describe the viability of the species in a manner that will address the needs of the species in terms of the 3 R’s. We considered a range of potential scenarios that may be important influences on the status of the species, and our results describe this range of possible conditions in terms of how many, how much, and where habitat protections are needed to persist into the future. (Table ES-1).
FUTURE CONDITIONS (Viability)
|Resiliency: large populations able to withstand stochastic events||Adequate water quality and quantity; sufficient herbaceous groundcover and sufficient habitats with suitable soils.||Of the 13 known populations, 4 highly and 5 moderately resilient populations.||Overall:Loss of 4-6 high and moderately resilient populations by 2070
Status quo:3 highly and 2 moderately resilient populations by 2070
Intermediate:2 highly and 2 moderately resilient populations by 2070
High:1 highly and 2 moderately resilient populations by 2070
|Redundancy: number and distribution of populations to withstand catastrophic events||Multiple resilient populations throughout the eastern and western portions of range of the species.||Overall, 54% reduction in habitat throughout range from historic levels. 1 highly and 3 moderately resilient populations in the west; 3 highly and 2 moderately resilient populations in the east.||Overall:By 2030, 33-44% reduction in resilient populations; by 2050 and 2070, 44-66% reduction in resilient populations
Status quo:By 2070, 0 highly and 1 moderately resilient populations in the west; 3 highly and 1 moderately resilient populations in the east
Intermediate:By 2070, 0 highly and 1 moderately resilient populations in the west; 2 highly and 1 moderately resilient populations in the east
High:By 2070, 0 resilient populations in the west; 1 highly and 2 moderately resilient populations in the east
|Representation: genetic and ecological diversity to maintain adaptive potential||Decreased genetic inbreeding and less population isolation||Local endemic species historically functioning as one metapopulation but now fragmented into 13 known populations with genetically distinct groups in the eastern and western portions of range.||Overall:By 2070, 44-67% reduction in representation.
Status quo:By 2070, 75% reduction in representation in the western group; 20% reduction in representation in the eastern group
Intermediate:By 2070, 75% reduction in representation in the western group; 40% reduction in representation in the eastern group
High:By 2070, 100% reduction in representation in the western group; 40% reduction in representation in the eastern group
Credit: Panama City crayfish photo in the site header CC-BY U.S. Fish and Wildlife Service.