Planning for Species Planning for Species Translocations and Translocations and ReintroductionsReintroductions
Reed F. NossReed F. NossUniversity of Central Florida University of Central Florida
Why Translocate or Why Translocate or Reintroduce Populations?Reintroduce Populations? Many regions have suffered local extinctionsMany regions have suffered local extinctions Missing species sometimes played critical Missing species sometimes played critical
roles in their ecosystems, so reintroduction roles in their ecosystems, so reintroduction can restore those functionscan restore those functions
Reintroductions can increase the range and Reintroductions can increase the range and overall population size of species, enhancing overall population size of species, enhancing probability of persistence (so, reintroduction probability of persistence (so, reintroduction usually part of recovery plans)usually part of recovery plans)
Many extant populations are small and Many extant populations are small and inbred, so translocations can restore genetic inbred, so translocations can restore genetic integrity and fitnessintegrity and fitness
Translocation can potentially save individuals Translocation can potentially save individuals that would otherwise be lost to developmentthat would otherwise be lost to development
Humans have an ethical obligation to restore Humans have an ethical obligation to restore what we have degradedwhat we have degraded
Be Cautious!Be Cautious! Many translocations and reintroductions are Many translocations and reintroductions are
failures (e.g., 56% - 89% of translocations failures (e.g., 56% - 89% of translocations failed; Griffith et al. 1989, Beck et al. 1994)failed; Griffith et al. 1989, Beck et al. 1994)
A review of 91 herpetile translocations from A review of 91 herpetile translocations from 1991-2006 found that 42% were successful, 1991-2006 found that 42% were successful, 28% failed, and 29% had unknown success 28% failed, and 29% had unknown success (Germano and Bishop 2008). (Germano and Bishop 2008).
Translocations to established populations can Translocations to established populations can lead to outbreeding depression or disease lead to outbreeding depression or disease transmission (to the same or related species)transmission (to the same or related species)
Long-term studies are required before Long-term studies are required before deeming any translocation a “success” – at deeming any translocation a “success” – at least several decades for long-lived speciesleast several decades for long-lived species
Steps in TranslocationSteps in Translocation
Feasibility studyFeasibility study Preparation phasePreparation phase Release phaseRelease phase Monitoring and evaluation phaseMonitoring and evaluation phase
Ask critical questions: Why is Ask critical questions: Why is reintroduction needed? Will the reintroduction needed? Will the reintroduced population be viable?reintroduced population be viable?
Factors that Influence Factors that Influence Reintroduction SuccessReintroduction Success
Rigorous planning, including consideration of Rigorous planning, including consideration of habitat suitability, landscape context, and habitat suitability, landscape context, and long-term population viability long-term population viability
Demographic and genetic characteristics of Demographic and genetic characteristics of translocated individuals (and recipient translocated individuals (and recipient population, if extant)population, if extant)
Use of wild-born vs. captive-reared individualsUse of wild-born vs. captive-reared individuals Number of individuals releasedNumber of individuals released Release into core or periphery of rangeRelease into core or periphery of range Controlling or eliminating factors that Controlling or eliminating factors that
extirpated the species originally extirpated the species originally Commitment to manage habitat and (if Commitment to manage habitat and (if
necessary) the population indefinitelynecessary) the population indefinitely
Rigorous Planning: Rigorous Planning: Include Empirical Include Empirical Assessments and Assessments and Modeling Modeling
Field habitat evaluations in donor and Field habitat evaluations in donor and recipient sitesrecipient sites
Habitat suitability modeling – ideally, Habitat suitability modeling – ideally, based on empirical data from extant based on empirical data from extant populations in the same regionpopulations in the same region
Spatially-explicit population modelingSpatially-explicit population modeling Consideration of alternative future Consideration of alternative future
scenariosscenarios Validation and revision of models based Validation and revision of models based
on new informationon new information
Or other surrogate of prey productivity
Demographic potential of wolves under current landscape conditions and moderate mortality risk scenario, as predicted by PATCH. Areas in yellow have <50% probability of occupancy.
From:Carroll (in prep).
Demographic potential of wolves under future (2025) landscape conditionsand moderate mortality risk scenario.
From:Carroll (in prep).
Predicted recolonization potential for wolves under current landscape conditions and moderate Canadian mortality risk scenario, assuming a 250 km/yr maximum dispersal distance over 200 years.
From:Carroll (in prep).
Predicted recolonization potential for wolves under current landscape conditions and moderate Canadian mortality risk scenario, assuming a 1500 km/yr maximum dispersal distance over 200 years.
From:Carroll (in prep).
Predicted potential for wolf dispersal from a reintroduction site in northern Maine to other areas of the northeastern U.S. and southeastern Canada under current landscape conditions and moderate mortality risk scenario over 200 years.
From:Carroll (in prep).
Demographic and genetic Demographic and genetic characteristicscharacteristics
Release juveniles or adults?Release juveniles or adults? Select individuals from a donor population Select individuals from a donor population
close to recipient site, if possibleclose to recipient site, if possible Release a large number of individualsRelease a large number of individuals Release a genetically diverse mix of Release a genetically diverse mix of
individuals, if possibleindividuals, if possible If augmentation, analyze genetics of donor If augmentation, analyze genetics of donor
and recipient populations to guard against and recipient populations to guard against inbreeding and outbreeding depressioninbreeding and outbreeding depression
Release Adults or Release Adults or Juveniles?Juveniles?
Seemingly more efficient to release Seemingly more efficient to release adults, as they can breed immediatelyadults, as they can breed immediately
However, integrating genetic with However, integrating genetic with demographic considerations, one demographic considerations, one recent modeling study of griffin recent modeling study of griffin vultures found that release of juveniles vultures found that release of juveniles reduced long-term extinction risk from reduced long-term extinction risk from the accumulation of mutations (Robert the accumulation of mutations (Robert et al. 2004)et al. 2004)
Wild-born or Captive-Wild-born or Captive-reared?reared? Griffith et al. (1989) review of mammal Griffith et al. (1989) review of mammal
and bird translocations showed greater and bird translocations showed greater success with wild-born animals, as success with wild-born animals, as expected from selection theoryexpected from selection theory
A few generations of domestication can A few generations of domestication can have negative effects – e.g., for steelhead have negative effects – e.g., for steelhead trout, genetic effects of domestication trout, genetic effects of domestication reduce subsequent reproductive reduce subsequent reproductive capabilities by ca. 40% per generation capabilities by ca. 40% per generation when fish are moved to natural when fish are moved to natural environments (Araki et al. 2007)environments (Araki et al. 2007)
However, in some cases (e.g., black-However, in some cases (e.g., black-footed ferret) captive breeding is the only footed ferret) captive breeding is the only choicechoice
Rapid population growth of black-footed ferrets Rapid population growth of black-footed ferrets in Shirley Basin, WY. Releases of captive-born in Shirley Basin, WY. Releases of captive-born animals ended in 1994. Lambda since 2000 animals ended in 1994. Lambda since 2000 estimated as 1.35estimated as 1.35(from Grenier et al. 2007)(from Grenier et al. 2007)
Release into Core of Release into Core of Original Range?Original Range? Reviews (Griffith et al. 1989, Wolf et al. Reviews (Griffith et al. 1989, Wolf et al.
1996) suggest release into core of 1996) suggest release into core of historical range is preferablehistorical range is preferable
For many mammals and birds, however, For many mammals and birds, however, ranges have collapsed from the center ranges have collapsed from the center outward, with peripheral populations outward, with peripheral populations persisting (e.g., Lomolino and Channell persisting (e.g., Lomolino and Channell 1995, 1998) 1995, 1998)
Perhaps peripheral populations are, in Perhaps peripheral populations are, in sum, adapted to a greater range of sum, adapted to a greater range of conditions and are pre-adapted to conditions and are pre-adapted to anthropogenic disturbanceanthropogenic disturbance
Hard or Soft Release?Hard or Soft Release?
Hard release – individuals are Hard release – individuals are released immediately into recipient released immediately into recipient site without any assistancesite without any assistance
Soft release – individuals are Soft release – individuals are released with supplemental food, released with supplemental food, shelter, etc. or kept penned, then shelter, etc. or kept penned, then often gradually weaned away from often gradually weaned away from human assistancehuman assistance
Site fidelity by penning treatment in gopher tortoises. Dispersers (unshaded) are individuals that travelled > 1 km from core release area without establishing a burrow. (From Tuberville et al. 2005)
Control or eliminate the factors Control or eliminate the factors that extirpated the species that extirpated the species originally!originally!(Caughley’s declining (Caughley’s declining population paradigm)population paradigm)
Apply Rigorous Criteria Apply Rigorous Criteria to Evaluate to Evaluate TranslocationsTranslocations(Ostermann et al. 2001)(Ostermann et al. 2001) Survival and recruitment rates in donor Survival and recruitment rates in donor
populationpopulation Survival rate of released animalsSurvival rate of released animals Recruitment rate of released animalsRecruitment rate of released animals Growth rate of reintroduced or augmented Growth rate of reintroduced or augmented
population (at recipient site)population (at recipient site) Establishment of a viable (self-sustaining) Establishment of a viable (self-sustaining)
populationpopulation
However, as of 1994, less than half of However, as of 1994, less than half of reintroduction projects had been assessedreintroduction projects had been assessed
Key Research Key Research QuestionsQuestions(Armstrong and Seddon (Armstrong and Seddon 2007)2007)Population LevelPopulation Level How is the establishment probability How is the establishment probability
affected by size and composition of the affected by size and composition of the release group?release group?
How are post-release survival and How are post-release survival and dispersal affected by post-release dispersal affected by post-release management?management?
What conditions are necessary for What conditions are necessary for persistence of the reintroduced persistence of the reintroduced population?population?
How will genetic makeup affect persistence How will genetic makeup affect persistence of the reintroduced population?of the reintroduced population?
Key Research Questions Key Research Questions (cont.)(cont.)
Metapopulation LevelMetapopulation Level How heavily should source How heavily should source
populations be harvested?populations be harvested? What is the optimal allocation of What is the optimal allocation of
translocated individuals among translocated individuals among sites?sites?
Should translocation be used to Should translocation be used to compensate for isolation?compensate for isolation?
Key Research Questions Key Research Questions (cont.)(cont.)
Ecosystem LevelEcosystem Level Are the target species/taxon and its Are the target species/taxon and its
parasites native to the ecosystem?parasites native to the ecosystem? How will the ecosystem be affected How will the ecosystem be affected
by the target species and its by the target species and its parasites?parasites?
How does the order of How does the order of reintroductions affect the ultimate reintroductions affect the ultimate species composition?species composition?
Gopher Tortoise Gopher Tortoise “Relocations” – the biggest “Relocations” – the biggest translocation issue in translocation issue in FloridaFlorida
Need for GT Need for GT Relocations?Relocations? In Florida, the stronghold of the species, In Florida, the stronghold of the species,
populations have declined 50-60% over the populations have declined 50-60% over the past 60-93 yearspast 60-93 years
FWC reclassified the GT from SSC to FWC reclassified the GT from SSC to Threatened in 2007, and it is in review for Threatened in 2007, and it is in review for listing as Threatened under the federal ESA listing as Threatened under the federal ESA (the western population already is listed)(the western population already is listed)
Incidental take (burying alive) is no longer Incidental take (burying alive) is no longer permitted, and relocations are now the permitted, and relocations are now the major conservation measuremajor conservation measure
History and Future of History and Future of GT RelocationsGT Relocations Relocations began in the 1970s Relocations began in the 1970s
and were permitted by GFC (FWC) and were permitted by GFC (FWC) since the mid-1980ssince the mid-1980s
Virtually no monitoring of Virtually no monitoring of relocated populations has occurredrelocated populations has occurred
No review of relocation success No review of relocation success has been conducted, except a has been conducted, except a couple local case studiescouple local case studies
History and Future of History and Future of GT Relocations (cont.)GT Relocations (cont.)
Since GTs are long-lived, at least 20 years of Since GTs are long-lived, at least 20 years of monitoring post-relocation are needed (Dodd monitoring post-relocation are needed (Dodd and Siegel 1991)and Siegel 1991)
Problems identified with past relocations: Problems identified with past relocations: - difficulty identifying suitable recipient sites - difficulty identifying suitable recipient sites
- movement of tortoises to sites with little or no - movement of tortoises to sites with little or no consideration of population demographics, habitat consideration of population demographics, habitat quality and long-term management quality and long-term management
- translocation of tortoises to sites later slated for - translocation of tortoises to sites later slated for development themselves development themselves
Problems (cont.)Problems (cont.) lack of consideration of conservation lack of consideration of conservation
genetics and potential outbreeding genetics and potential outbreeding depression depression
disruption of resident population social disruption of resident population social structure and behaviors structure and behaviors
the tendency for GTs to exhibit homing the tendency for GTs to exhibit homing behavior and low site-fidelity once being behavior and low site-fidelity once being movedmoved
transmission of disease and parasitestransmission of disease and parasites human predation at recipient sites human predation at recipient sites
The missing component of The missing component of GT translocations: GT translocations: commensals!commensals! GT burrows provide shelter for ca. GT burrows provide shelter for ca.
360 other species, including 360 other species, including amphibians, reptiles, insects, and amphibians, reptiles, insects, and mammals, some of which are mammals, some of which are federally and/or state-listed species federally and/or state-listed species and are obligate commensalsand are obligate commensals
Yet, the commensals are not Yet, the commensals are not translocated with the tortoises!translocated with the tortoises!
Manage Habitat and (if Manage Habitat and (if necessary) the Population necessary) the Population IndefinitelyIndefinitely Funding must be secureFunding must be secure Performance must be monitored and Performance must be monitored and
enforcedenforced Net habitat loss must be reversedNet habitat loss must be reversed
But 2.7 million acres of natural and semi-But 2.7 million acres of natural and semi-natural habitat in Florida is predicted to be natural habitat in Florida is predicted to be lost by 2060 (Zwick and Carr 2006), lost by 2060 (Zwick and Carr 2006), including at least 700,000 acres of GT including at least 700,000 acres of GT habitat (FFWCC 2006) – this will not work!habitat (FFWCC 2006) – this will not work!
There is a better future possible - a There is a better future possible - a net gain in natural and semi-net gain in natural and semi-natural habitatnatural habitat
