Amphibians & Reptiles Flashcards
According to the IUCN how many reptiles have been studied in regards to risk assessment and how many are at risk of extinction?
1500 so far with 20% at risk of extinction
How many species of amphibians have been found so far, what is the most dominant phylum and how many are found in the UK?
7,457 species - 88% are anura
6 species of amphibians in the UK - common toad, common frog, smooth newt, great crested newt, palmate newt, natterjack toad
Why are amphibians important?
Good indicator species - live in both aquatic and terrestrial environments
- permeable skin makes them sensitive to changes in their environments
Ecosystem services - nutrient cycling - herbivorous tadpoles
- Invertebrate predators
- Prey for small mammals/ birds
- Make up large proportion of an ecosystems biomass
Medicine - cancer treatment drugs
Cultural - symbol of wisdom and good fortune in many cultures
What threats do amphibians face?
Habitat destruction - deforestation, wetland drainage
Pollution - agricultural, industrial, pollutant mixtures
Invasive species - amphibians, fish
Disease - chytrid fungus, ranavirus, trematode worms
Overexploitation - frogs as food, pet trade
What is possibly the worst disease in recorded history in terms of its effect on biodiversity?
Chytridiomycosis
First identified in 1998, has been detected on at least 287 species of amphibians in 36 countries
Caused catastrophic decline/extinction in at least 200 species
Can be spread via human shipping which leads to 1) escape of infected amphibian 2) intentionally set free or 3) water from infected tank released into environment
Native amphibian populations generally have no evolved defences against the pathogen
Climate change can make conditions more hospitable as well as reducing amphibian immune systems through stress
Pollution can also reduce immune system making them more susceptible to pathogens
Name and describe how a herbicide has affected amphibian decline and who carried out this study
Rohr et al (2008)
Atrazine - Reduces suspended algae and compromises amphibian immune response
- Increases water quality and thus sunlight reaching attached algae
- Increases attached algae, the food source for snails
- Increases snails, the first intermediate hosts of parasites
- Increases exposure of amphibians to parasite and due to compromised immune system increases the susceptibility of amphibians infected
- Increases amphibian larval parasite loads
- Increases the risk of amphibian mortality
How can amphibians habitats be protected?
Creation and restoration - wetlands, habitat corridors, garden ponds
Agriculture - retention or implementation of farmland ponds
- removal of invasive species from water bodies that predate on amphibians (eg trout)
- field buffers to reduce run-off
- organic agriculture
Domestic - Preventing the use of pesticides in gardens
- reducing the use of chemicals in the home
- using environmentally friendly cleaning products
How can the risk of disease be contained in amphibians?
Reduction of pathogen spread - education - preventing the moving around of amphibians
- through cleaning of equipment/clothing used by scientists to avoid the spread of disease
Developing survival assurance colonies - can be used to re-introduce into the population
Remedial disease treatment - limiting the prevalence of infection by treating individual hosts or habitats
- agricultural fungicides
Which countries are responsible for the decline in frogs via overexploitation?
Europeans consumed roughly 120 million frogs legs per year in the 1990’s
Indonesia - responsible for 45% of the wolrd’s frog legs exports
- domestic market 2-7x larger
China - major exporter of frogs legs - farmed and wild
India - Indian bullfrog hunted during monsoon season
Belium/France/US - major importers of frogs legs
What organisations are there in the UK for protecting amphibians?
British herpetological society
Froglife
Amphibian and reptile conservation
How many known species of reptiles are there, what is the most common phylum and how many are found in the UK?
10,000 species, 955 of which are squamata
6 species found in UK - Grass snake, adder, smooth snake, common lizard, slow worm, sand lizard
Why are reptiles important?
Ecosystem maintenance - predators and prey at different parts of lifecycles
- herbivorous species important for seed dispersal
- pollinators
- top predators
Pest control - predate on rodents and insects
Medicine - snake venom for vaccines
What threats do reptiles face?
Habitat destruction - wetland drainage, deforestation
Invasive species - rats, cats, mongoose, pigs, fire ants
Pollution - bioaccumulation of far soluble contaminants in eggs
- plastic pollution in marine turtles
Overexploitation - freshwater turtle and tortoises for food
- marine turtle for eggs
- pet trade
Climate change - temperature dependant sex determination
Give an example of how captive breeding is helping a species of reptile in the UK
Sand lizards have declined in the UK
Captive breeding is useful as sand lizard requires both mature sunny habitats and open undisturbed sand
- in the wild predation and disturbance to egg laying areas mean that only 5% survive to adulthood
- Since sand lizards cannot disperse far over hostile habitats they won’t colonise newly suitable areas
Reintroduction programme has undertaken 76 re-introductions to both dune and heathland sites in England and Wales - 9000 animals released through programme
Sand lizards have now been re-established at many other sites and dune sites are now protected
How can marine turtles be protected?
Reduce illegal international trade in sea turtles and their products by enforcing laws and agreements
Decrease the turtle deaths caused by commercial fishing through enforcement of Turtle Excluder Device (TED) and gill net regulations
Protect nesting beaches by establishing parks and refuges or through regulations combined with public education initiatives
Eliminate disturbances at nesting beaches by decreasing artificial lighting, halting beach armoring, regulating beach nourishment and limiting the impacts of people on the beach
Enforce laws to limit dumping of pollutants and solid waste into the ocean and nearshore waters
Increase public awareness and community participation in sea turtle conservation through education programmes
Reduce plastic pollution in the oceans
