M3: Lecture 3 Relict Leopard Frog Status Pt3

Review: what were the two sites that had naturally established populations of R. onca

Northshore and Black Canyon

What was the stochastic event in Black Canyon and what year?

In October of 2006, there was a major storm that caused debris flows and flooding that tor out vegetation and restructured landscape

Has historical populations in Black Canyon recovered from the stochastic event?

Not really. They have barely recovered with low numbers.

How did they monitor relative abundance of historical and translocated frogs?

VES (Visual Encounter Survey)

How many frogs were estimated for relative abundance in 2017?

1163 count in 2017

What was the 1163 count of frogs considered as?

Minimum total population estimate. Still unclear of how much % of this was to the real population

By what method were estimates of true abundance measured by?

Mark- Recapture (Catch, mark, and release a sample of animals)

Then sample again, keeping track of those that are marked and unmarked

What formula is the true abundance of the population estimate by?

X (total population) / M (marked) = C (total captured in second sample) / R (recaptures)

What was the Lincoln-Peterson Estimator?

the simplest method of taking such estimates of population sizes from mark-recapture data

What was the double sampling method used for population estimates?

Conducting Mark-Recapture and VES

How was the double sampling method calibrated?

Calibrated the relative abundance from VES to estimates of true abundance from Mark-Recapture

Then apply the ratio to VES data from other sites where there is no estimate of true abundance

What did the double sampling method provide ?

Essentially provides ratio or correction factor to adjust VES data

What was the change in total population over time per the given table of estimates for the entire species?

Slowly increasing over time, probably not as much as people would want, but still increasing.

What are the 4 points to translocation success criteria?

1. Overwintering

2. Breeding Activity

3. Natural Recruitment

4. ‘Sustainable’ Population

What is meant by overwintering as part of the translocation success criteria?

Do spring tadpoles/juveniles survive to next spring as growing juveniles/ grown adults?

What meant by breeding activity as part of the translocation success criteria?

Egg masses, tadpoles born at site

What is meant by natural recruitment as part of the translocation success criteria?

an animal that was born at a site from a parent animal that was already at such site. Often determined years after final release

What is meant by sustainable population as part of the translocation success criteria?

Is this population sustainable over time?

What is included in habitat management at sites?

Mechanical vegetation reduction making ideal habitats for frogs

What was involved in maintaining important breeding pools?

Mostly volunteer crews maintaining important breeding pools in a drainage ditch along an access road at Hoover Dam

What was the USFWS Multidistrict Litigation Review Translocation? What year?

In 2011, a legal agreement was made with Wild Earth and Center for Biological Diversity to conduct actions under ESA for 251 Candidate species, including R. onca.

Lawsuits challenged USFWS as this legally forced the USFWS to break its backlog of Candidate species and to determine listing for Endangered species.

What was the Species Status Assessment used for in 2016?

To inform listing decisions for endangered species

What 4 updated factors were included in the Species Status Assessment?

1. Updated distribution

2. Updated status of populations

3. Updated current threats

4. Updated mitigation needs

Prior to the USFWS listing deiscion what was signed in 2016?

Revision and Renewal of the Conservation Agreement, Assessment, and Strategy Plan

What were the five factors identified as current stressors in 2016 from the Species Status Assessment?

1. Present or threatened destruction or curtailment of habitat or range

2. Overutilization

3. Disease or Predation

4. Inadequacy of regulatory mechanisms

5. Other natural or manmade factors affecting continued existence

Which of the five factors of current stressors did not really apply?

2. Overutilization 4. Inadequacy of regulatory mechanisms

Name 3 of the five factors that were really considered current identified stressors

1. Present or threatened destruction or curtailment of habitat or range

2. Disease or predation

3. Other natural or manmade factors affecting continued existence

What were the 6 factors of the current threat: Present or threatened destruction or curtailment of habitat or range?

1. Habitat degradation (ex: Lake Mead drying out)

2. Ground water diversion and withdrawal

3. Overgrowth of emergent vegetation

4. Nonnative plants

5. Burro and cattle grazing (but also a benefit)

6. Reduced connectivity of populations (but also a benefit)

What were the 4 factors of the current threat: Disease or predation?

1. Nonnative crayfish, bullfrogs, fishes

2. Amphibian chytrid pathogen

3. Chytrid pathogen present within historical range and in one population of R. onca

4. Negative impact on R. onca surviorship

What was originally thought of regarding the chytrid pathogen, making people think it was not big deal?

They though it could not survive hot desert conditions

What showed from initial research of the chytrid pathogen?

Showed that frogs were resistant to two final isolates that were virulent in other frog species

What was the initial survivorship % of infected frogs? Did they show any signs of chytridiomycosis

96% survival of infected frogs, showed no signs of chytridiomycosis with 64% infection clearance

At which location did some wild frogs survive and potentially clear this infection?

Northshore

But was was the chytridiomycosis situation really?

more complex than initially thought of

How was the situation more complex?

R. onca frogs are susceptible to isolates of the pathogen from the local environment

What did this more complex situation do to the survivorship of frogs?

Lowered the survivorship of adult frogs and especially during metamorphoses

Why were frogs in metamorphosis more susceptible than adult frogs?

This process potentially shuts down some parts of their immune system making them highly susceptible

What was concluded regarding the chytrid pathogen?

It is a factor in the decline of Rana onca and appears to be a factor limiting property

What were the 3 factors of the current threat: Other Natural or Manmade Factors

1. Small population size

2. Flash flood events (also a benefit)

3. Drought and Wildfire (climate change)

How are flash flood events also a benefit to these frog populations?

Some levels of flooding can open up portions of vegetation which makes ideal habitats for frogs.

What concerning climate change is a predicted problem as a current natural stressor

Predicted increase in temperature, but not a decline in precipitation

When was the USFWS Listing Decision made?

October 6, 2016

What was the listing decision made in 2016 by the USFWS?

Listing the Relict Leopard Frog as endangered or threatened was “not warranted” and it was removed from candidate status

For what provided reasons was removing the Relict Leopard Frog from candidate status and not listing it as endangered or threatened and considered as a good thing?

1. Substantial increase in occupied sites

2. Upward trend in abundance

3. Active, dedicated voluntary conservation team

4. Renewal of conservation agreement and strategy

5. History of funding commitments

Potential question in exam “for fun”: What was the Biological Species Concept

Defines a species as a group of populations whose organisms who are actually or potentially interbreeding successfully in nature to provide viable offspring and are reproductively isolated from other groups

Potential question in exam “for fun”: What are the three main goals of conservation biology?

1. Document the full range of biodiversity

2. Investigate human impacts on genetic variations, species, communities, and ecosystems

3. Develop practical approaches to prevent the extinction of species, maintain genetic diversity, and protect and restore biological communities and their associated ecosystem functions

Potential question in exam “for fun”: What is the difference between a conservationist and a preservationist?

Conservationists are more concerned on the sustainable use and management of natural resources while a preservationist focuses on protecting nature and the land with minimal human interference