Carnivore Reintroductions — Before, During, and After; Variables and Case Studies to Consider for the Northeastern U.S. (Part 2)

The following article is the second of a three-part series, an adaptation of a presentation the author gave at the Northeast Natural History Conference in Burlington, Vermont, Earth Day weekend, 2023. Note: “Before, During, and After” refers to both 1) phases during species reintroduction programs in the United States that are executed, underway, and currently considered, as well as 2) phases of a hypothetical puma (Puma concolor) reintroduction program needed for puma recovery in the Northeast. References follow the article.

Part 2

Having considered nine real-life reintroduction or population augmentation programs of seven different large carnivore species or subspecies in the United States, across 65 years of history and policy, we can begin to robustly conceptualize what a puma (Puma concolor) reintroduction to the Northeast could entail. That is, as a (worthwhile) exercise, we can begin to design a hypothetical puma reintroduction program — its “before” phase, and also visualize and conceptually prepare for post-release puma monitoring — its “during” phase.

A team led by wild-cat conservation organization Panthera published a puma habitat suitability analysis earlier this year for the eastern United States¹. It sourced expert opinion from published scientific literature for habitat inputs, and applied two patch size thresholds to discern patches, with the larger of 10,000km² (3,861mi²) being more likely to ensure the genetic health of a population through time², that is, a patch more likely to ensure an “effective” puma population size (N_e) of over 50 animals³. (Note: The Panthera-led team used the metric Dellinger et al. (2020)² used for genetic health. It, in turn, is from Ian Franklin (1980)³, who stressed that long-term genetic variability for a randomly mating mammal population, not just its avoidance of inbreeding depression, necessitates an N_e of at least 100 individuals.) The team also quantified several landscape characteristics per patch such as livestock density and portion of public land, as well as human density and an index inferring human valuation of wildlife, to compare patches. The team identified 13 suitable habitat patches for puma of at least 10,000km² in the eastern U.S., 6 of which are in the Northeast. All 6 northeastern sites are hilly to mountainous: the Catskills and Adirondacks, the western and eastern regions of the Green Mountains, and the western and eastern regions of lower Maine. This is important when planning for all aspects of the implemented reintroduction program.

We will not hone in on one northeastern state to imagine the public debate and ultimate decision to reintroduce puma in collaboration with that state’s wildlife agency. This part of the program’s Before phase is nothing to gloss over, however. Puma have been extirpated from the Northeast for 100 years or more. (The U.S. Fish and Wildlife Service concluded the eastern puma was extinct north of Florida in 2011, and removed it from the endangered species list in 2018.) Formal stakeholder deliberation of reintroduction may be politically substantial then, and unique to each state. But, to proceed: Assuming funding has been secured and an expansive reintroduction site agreed to by necessary parties, project leaders will need to approach state wildlife agencies for permits to translocate individuals from source states to release states. (Since the puma outside of Florida is not federally protected, current research indicates a federal permit for handling and transport would not be needed between states north of Florida.)

(It’s worth noting: Of the Northeast states, New York has perhaps had the most scrutiny as a potential region for puma recovery. Earlier rounds of puma habitat modeling were produced by Laundré (2013)⁴ for New York’s Adirondack Park, and by Glick (2014)⁵ for New York east of the Hudson River and all of New England. McGovern and Kretser (2014, 2015)^6,7 studied social sentiment about puma recovery in the Adirondack Park. This body of work produced favorable results for puma habitat suitability and social receptivity of puma recovery. In general today, puma recovery east of current breeding populations is an active area of research for multiple parties.)

Puma could be sourced for translocation from multiple states. Sixteen states have breeding populations⁸ and cultural attitudes within them vary. Deciding on the number of individuals to translocate successfully first, the term “successful” also defined (for example: survives one year, establishes a home range, attempts to breed, etc.) will also guide puma source planning. For the degree of resources and scale of planning involved, we can say every puma captured, translocated, and released should qualify as an expected breeder, i.e. an individual who would count toward the target effective population size (N_e). N_e should be no less than 50 individuals to seed this new, isolated puma population. At least 100 unrelated, or distantly related individuals can be the better target for its genetic health. Reintroducing this many animals would entail multiple years of translocations, allowing project staff and leaders to operate carefully, adaptively, and simply break in to what would be a high-profile project in its first season and year. There would also quickly be overlap of reintroduction activity and monitoring activity, warranting preparedness for all that can happen post-release.

“Rescuing” puma from states like Texas, where the species has no protection, and is not managed scientifically with a data-informed management plan⁹ can be one strategy. Doing the same from states where populations are small and management controversial, such as Nebraska^10,11, is another. Source states would need to agree to these removals. A cooperating state’s wildlife agency may officially support translocation, or humane removal of  “nuisance” cats out of state, but it may also need to contend with constituent perception of lowered hunting opportunity of puma as a game species. Sourcing puma from forested states of similar latitude such as Washington and Oregon to ease potential acclimation stress can also be wise. Similar elevation can be considered as well.

Puma captured for translocation will need health assessments. A veterinarian experienced in wildlife health, ideally with One Health awareness, should consult on the reintroduction program. State veterinarians employed by both the source states and release state may also want or need to be involved as part of the cooperative process. What puma health metrics are assessed and how will depend on handling from the point of capture, the translocation period between states, and if individuals go through a hard (expedited transport and release upon site) or soft (acclimation period at release site and provisioning) release protocol, or some degree in between, in the population recovery area.

Puma cubs are independent from their mothers at about 1.5 years of age (range: 10-24 months)¹². Males and females of this age can be considered for translocation upon capture if they pass an initial health screening designed by project biologists and consulting veterinarians. All puma will be collared for monitoring, so all puma deemed fit to undergo an immobilization procedure for collaring can undergo a more thorough health exam at that time. Body condition can be assessed, ecto- and endoparasites screened for using blood and feces if possible, a complete blood count and blood chemistry can be evaluated, and the following diseases screened for where possible: avian flu, canine distemper, feline distemper, feline immunodeficiency virus, feline leukemia virus, heartworm, SARS CoV-2, and toxoplasmosis. Feline infectious peritonitis is also known in the Florida panther (P. c. coryi), but potentially due to its historically reduced genetic diversity and immunocompetence¹³. Armstrong, DVM (2020) of the Henry Doorly Zoo and Siberian Tiger Species Survival Plan recommended vaccination for 6 diseases “for normal, healthy tigers” for proactive measures, but stressed no vaccines were legally approved for non-domestic felid use; vaccine effectiveness was unknown¹³. Proactive vaccination for translocated pumas can be a discussion point for consulting veterinarians. Overall, reintroducing puma to a landscape from which they’ve been absent for roughly a century warrants serious consideration of a health protocol to design and implement.

A spatial strategy for releases is also important. The program’s intent is to seed a vigorous breeding population in a chosen landscape. The goal is for puma to establish home ranges local to where released, and find one another for breeding. Choosing how far apart to release individuals, what sex, when, and where deserves forethought. Male puma home ranges can overlap multiple female home ranges¹⁴ so releasing designed clusters of say 1.2 cats (1 male to 2 females) is a potential strategy. Washington State reported its density of cats is usually <4.0/100mi² in suitable habitat¹⁵. Oregon reported densities of 2.3-11.9 cats per 100mi² in mountainous regions, but included all age groups, or yearlings and adults¹⁶. Montana reported a density estimate for its northwest puma ecoregion, one of four delineated for population monitoring (the three western ones with more data inputs than eastern)^17,18, as 9.7/100mi^{2 18}. Importantly, puma are hunted and managed in these western states. They would not be during a northeastern reintroduction program. How protected puma occupy the northeast recovery region’s suitable habitat would be a salient research topic. Monitoring released individuals would begin immediately, which can inform the spatiotemporal aspects of subsequent release planning during the same season. Further, spatial analyses of cat behavior in early years can inform spatial release strategies in later years of the program.

The quality, function, and versatility of monitoring equipment, as well as its cost, are further project components to consider when designing a reintroduction program. The Olympic Cougar Project (OCP) is a large-scale, highly collaborative, long-term population monitoring project with fine-grained data collection. Puma dispersal behavior and habitat corridors are two research topics¹⁹ in the multi-faceted study which aims to support population and landscape connectivity in Washington State. The OCP has used Lotek Iridium GPS collars programmed to take location fixes every 2 hours¹⁹. Frequency of location fixes affects collar battery life, so biologists can program collars to optimize performance with project objectives in mind. Decisions to make in study design can be: Will individuals be recaptured and recollared for greater longitudinal datasets? (Will skilled hound teams be ready and reliable in the Northeast to tree puma safely, or should this part of the novel reintroduction program be executed by project staff?) Will collars also have remote-operated drop-off mechanisms? What will monitoring protocol be when females are thought to be rearing young? Is the project equipped with sufficient resources to shift to ground or aerial telemetry should positional components fail? Did parties budget for spare equipment?

Further operations to plan for are mortality investigations including carcass retrieval, storage capacity for carcasses, and necropsies. Consulting and/or cooperating veterinarians can perform them when causes of death are unclear. Carcass disposal, particularly for a large, multi-year project should also be planned. Deep pit burials are an option if carcasses are processed in batches, in which case a backhoe and front-end loader is useful, perhaps on government property. Project staff and cooperating governments can also articulate the steps to go through if poaching is suspected, including implementing a legal mechanism for illegal take of a reintroduced, formerly extirpated species if necessary.

All field staff should have first aid training and potentially search and rescue training since the northeastern puma recovery region can include rugged wilderness, like the Adirondacks. Cellular signal can be poor to nonexistent in such terrain, so staff can carry satellite communicators such as Garmin InReach® devices for essential and emergency communication. Communication flow in general should also be planned: who communicates what to whom and when, regarding unique aspects of this program, such as if cats cross state borders, and even national into Canada. What data is made public and when, and how, also deserves much forethought followed by conscientious action to balance project transparency with protection for released cats.

As the reintroduced population begins to grow, data amasses, teams gel, and operations break in, including regular staff meetings (consider weekly), preliminary analyses can begin for learning and reporting. A northeastern puma reintroduction program may be privately funded. A donor-supported organization, if involved, may need to not only produce internal progress reports and external annual reports, but generate reports for donors to demonstrate returns on investment, and also justify requests for further funding. Evaluation of project outcomes can be structured, for instance: per annum. State government officials may request their own debriefing. VIPs may want to attend field activities. Academics may approach to expand research capacity. As puma return to the Northeast after 100+ years, project personnel can nurture the entire program for forthcoming years as they, alongside all collaborators, collectively steward the nascent, reintroduced apex carnivore population.

Part 3 of this series transitions into potential ecological effects and socioeconomic impacts of puma reintroduction, what states have messaged about eradicated species, and a picture of puma stewardship going forward in the Northeast. 

Literature Cited

¹ Yovovich, V., N. Robinson, H. Robinson, M.J. Manfredo, S. Perry, J.T. Bruskotter, J.A. Vucetich, L.A. Solórzano, L.A. Roe, A. Lesure, J. Robertson, T. Butler, and L.M. Elbroch. 2023. Determining Puma Habitat Suitability in the Eastern USA. Biodiversity and Conservation, https://doi.org/10.1007/s10531-022-02529-z

² Dellinger, J.A., K.D. Gustafson, D.J. Gammons, H.B. Ernest, S.G. Torres. 2020. Minimum Habitat Thresholds Required for Conserving Mountain Lion Genetic Diversity. Ecology and Evolution, https://doi.org/10.1002/ece3.6723

³ Franklin, I.A. 1980. Evolutionary Change in Small Populations. In Soulé, M.E. and Wilcox, B.A. (Ed.), Conservation Biology: An Evolutionary-Ecological Perspective (pp. 135–149). Sinauer Associates, Sunderland, MA. 395pp.

⁴ Laundré, J. 2013. The feasibility of the north-eastern USA supporting the return of the cougar Puma concolor. Oryx, 47(1): 96–104.

⁵ Glick, H.B. 2014. Modeling Cougar Habitat in the Northeastern United States. Ecological Modelling, 285: 78–89.

⁶ McGovern, E.B. and H.E. Kretser. 2014. Puma concolor couguar in the Adirondack Park: Resident and Visitor Perspectives. Wildlife Conservation Society, Adirondack Program, Technical Paper #5. Saranac Lake, NY. 47pp.

⁷ McGovern, E.B. and H.E. Kretser. 2015. Predicting Support for Recolonization of Mountain Lions (Puma concolor) in the Adirondack Park. Wildlife Society Bulletin, 39(3): 503–511.

⁸ Mountain Lion Foundation. 2023. Mountain Lions in the United States, States with Confirmed Breeding Populations. https://mountainlion.org/state-by-state/. Accessed March 2023.

⁹ Elbroch, L.M. and P.M. Harveson. 2022. It’s Time To Manage Mountain Lions in Texas. Wildlife Society Bulletin, https://doi.org/10.1002/wsb.1361

¹⁰ Elbroch, L.M. 2023. Mountain Lion Populations [op-ed]. Omaha World-Herald. https://omaha.com/eedition/sunrise/articles/mountain-lion-populations/article_ccb78c64-dc92-5711-9049-30d1d0810c99.html. Accessed June 2023.

¹¹ Martirosov, D. 2023. Nebraska Expands Mountain Lion Hunting into Niobrara Valley — but Not Without Opposition. Lincoln Journal Star. https://journalstar.com/news/local/nebraska-expands-mountain-lion-hunting-into-niobrara-valley-but-not-without-opposition/article_7e9bba88-0ada-11ee-87fb-8f13de4b5f88.html. Accessed June 2023.

¹² Hunter, L. 2011. Carnivores of the World. Princeton Field Guides, Princeton University Press, Princeton, NJ. 240pp.

¹³ Armstrong, D. 2020. Siberian Tiger Species Survival Plan Vaccination Recommendations. American Association of Zoo Veterinarians. https://www.aazv.org/page/273. Accessed July 2023.

¹⁴ Sunquist M. and F. Sunquist. 2002. Wild Cats of the World. The University of Chicago Press. Chicago, IL. 452pp.

¹⁵ Western Wildlife Outreach. 2018. Discover Washington’s Cougars. Port Townsend, WA. 2pp

¹⁶ Oregon Department of Fish and Wildlife. 2017. 2017 Oregon Cougar Management Plan. Salem, OR. 205pp.

¹⁷ Montana Fish, Wildlife, and Parks. 2019. Montana Mountain Lion Monitoring and Management Strategy. Helena, MT. 139pp.

¹⁸ Montana Fish, Wildlife, and Parks. 2022. Northwest Mountain Lion Ecoregion Population Estimate Report, 2019–2021. Helena, MT. 16pp.

¹⁹ Stratton, A., R. Barbee, K. Sager-Fradkin, B.T. Ackerman, and L.M. Elbroch. 2022. Island Hopping Cougars (Puma concolor) in the Salish Sea. Northwestern Naturalist, 103: 236-243.