FNR24150 -- Week 16 Notes

Conservation of Amphibians and Reptiles

General Principles

Biodiversity crisis
- Loss and reduction in diversity at all levels (genetics → ecosystems)
- Primarily focus on single spp. conservation due to lack of resources for anything much bigger (e.g. habitat/environment)
Extinction
- Rate has greatly exceeded the “normal” historical rates
- Could lead to cascading extinction events
- The loss of one spp. causes the loss of multiple

Current trend: Amphibians

World-wide amphibian declines
- 1,260 of 6,000 spp. (21%) are endangered
- 1,856 of 6,000 spp. (32%) are threatened
- 2,469 spp. are in decline (43%)

Current trend: Reptiles

World-wide reptile declines
- Reptiles not completely assessed (mostly Chelonians)
- Best estimate 833 of 6,500 spp. (13%) endangered
- Turtles and tortoises well reviewed
- 108 of 257 spp. (42%) threatened

Human Impacts

Humans have modified the environment everywhere through
- Habitat modification, fragmentation, loss
- Most visible human mediated environmental change
- Agriculture
- Urban growth and paving
- Overall consequences:
  - Habitat alteration and fragmentation (dispersal barriers)
  - Increased mortality due to road kills
  - Loss of breeding, foraging, & over-winter areas
  - Population declines and extinction in some cases
- Road mortality
  - Skewed sex ratios in turtle populations
  - Predicted higher sex ratio skew in high road density
  - Road mortality of females on nesting migrations
  - Historical male-biased sex ratio?
  - Proportion of males increased linearly
  - Synchronized with increase in paced roads
  - Indiana Road Mortality
  - Surveyed Lindberg Road for 1.5 years
  - Vertebrate road mortality N=8,176
    - Herps represented n=8, 016
  - Miles of paved roads in Indiana ~93,600
- Harvest
- Mostly for commercial exploitation
  - Consumption (food and folk medicines)
  - Luxury trade (leathers, jewelry)
  - Pet Trade
- Focused on a relatively few spp. in any locality (developing countries)
- Sustainable harvest by small communities can also decimate populations
- Examples
  - Consumption: larger, long-lived spp. (Chelonians, specifically the Apalone and also Varanus lizards)
  - 1990’s Europe imported 6,000 tons of frog legs/year
  - India and Indonesia exported 50 million frogs/year
    - Banned exports in 1987 and 1992
    - Depleted natural insecticide from paddy fields
  - Luxury Trade: American Caimans → leather
  - Pet Trade: Box turtle declines in 16 states (~30,000 box turtles since 1995)
  - High prices for rare and brightly colored spp.
- Introduction of exotic spp.
- Exotic spp.: Introduced/non-native
  - Black and Norway Rats → great impact on islands (lizards, tuataras, tortoises)
  - Domestic cats → widespread damage in suburban and rural areas
  - Herbivores (goats, rabbits) → change vegetation
- American Bullfrog
  - Game spp. (frog legs)
  - large
  - High mobility
  - Live 7-9 years
  - Huge reproductive potential
  - Generalized feeding habits
  - Snakes, worms, crustaceans, insects--anything that fits in its mouth
  - California: bullfrogs reduced leopard frog survivorship by 33%
  - Arizona: bullfrogs responsible for leopard frog declines (79 out of 80 sites now extirpated; 79 sites completely devoid of leopard frogs)
- Management Tools
  - Establishment of refuges and corridors
  - Main objective: prevent extinction
  - Key issue: How much area to preserve?
  - Location, size, and shape of refuges and corridors is dependent on:
    - Whether spp., communities, and/or ecosystems are targeted for conservation
    - Natural history characteristics of the above
  - Minimum Viable Population (MVP)
    - Minimum area required for a population or spp. to survive
    - Studies of terrestrial buffer zones with freshwater turtles
    - Savannah River Ecology Laboratory (SREL)
    - Do protected acreage of wetlands protect areas critical for nesting and hibernating?
      - No, they do not
- Management of animals in captivity
- Animals can be managed in captivity for:
  - Short periods (temporary)
  - “Headstart” (from hatchling to 6-12 months)
  - Hatcheries (egg incubation)
  - Long periods
  - Duration of an individual’s life
  - Sometimes several generations
  - Crocodilian farming and ranching
- Reintroductions of wild spp.
- Intentional release of individuals to establish or enlarge the population of a target spp.
  - Target spp. usually threatened or endangered
- Some problems
  - Generally very few of the animals that are re-introduced survive
  - Introduction of diseases into healthy populations
  - Outbreeding depression
- Pollution
- Diseases

The Process of Amphibian Conservation: The Eastern Hellbender model

Phase 1
- Health & Genetics
- Sampled 10 states, 70 rivers, and 1200 samples
- Blood draws for health screens and DNA samples
- Two large clusters
  - Ohio River Drainage (Indiana, Ohio, West Virginia, Pennsylvania)
  - Tennessee River Drainage (Georgia, Tennessee, North Carolina, Virginia)
  - i.e. Hellbenders in Indiana are genetically similar to those in Ohio
- Sampling
- Population Assessment
- Understand how many Hellbenders you have
  - 88 in Dr. Williams’ case
- Density
  - 0.06/100m^2
- Spatial Ecology
- Health (blood work, sperm, weight class, etc.)
- Habitat & Home Ranges (radio transmitters and radio telemetry)
- Hellbenders are very rare; distributed randomly across the landscape with very little interaction between other Hellbenders
- Survival
- Annual Hellbender survival if no action is taken: 0.804
Phase 2
- Population Manipulation
- Recovery Strategies
  - Population Viability Analyses
  - Captive rearing and release
  - Translocations
  - Intra-river translocation
    - 10 native adults & 10 translocated adults
  - Captive relreases
    - 10 native adults
    - 10 captive juveniles
  - Spatial Ecology
    - Home range size nearly cut in half (2212 v. 1348 m^2)
    - Extensive HR overlap among individuals
    - Two egg clutches
  - Post-translocation
    - No impact on annual survivorship of adults (80% v. 78%)
    - 50% juvenile survivrship had exceeded 30% threshold to prevent extinction :D
- Outreach & Education
- Mail survey
  - 1378 Distributed
  - 281 to Riparian Landowners
  - 541 Completed (41%)
- In-person survey
  - 242 surveys conducted
  - 6 access sites
- Focus
  - Awareness, attitudes, behaviour
- Approach
  - “3D Model” of O & E
  - Develop the portal
  - Design the content
  - Deliver the programs
  - Evaluate impact
  - HelpTheHellbender.org
- Impact
  - Nationally
  - 25 organizations (6 state/fed agencies, 8 zoos, 11 universities)
  - 63% monthly
  - 82% follow
  - 81% recommend to others
- Population Modeling
- 2011-2012, 33 Hellbenders
- 2018, 5 male Hellbenders
- Must focus on juveniles
  - Increase juvenile survivorship → expected local extinction in 26 years goes up to 35
  - 30-50% increase → almost completely reverse the probability of Hellbender extinction
  - Problems with heavy predation → low juvenile survivorship
Phase 3
- Restoration
- Captivity can deprive animals of experiences/natural stimuli
  - Predator cues
  - Stochastic events
  - Refuge
  - Live prey
  - Habitat variability
- Advancing Headstarting
  - Introduce captive, juvenile Hellbenders to natural conditions to better prepare them for the wild
  - Investigate the effects of:
  - Moving water
  - Predator cues
  - Microbiome
  - 90% survivorship in 200 days, then averages around 75%
Phase 4
- Providing farmers federal grant money to implement conservation practices in watersheds

The Many Components of Conservation Biology

Research
Education/Outreach
Management
Captive breeding
Partnerships
- A collaboration with many interested bodies
- Semiannual meetings
- Action Teams
- Habitat
- Outreach & Education
- Captive Rearing/Breeding
- Animal Health