What is Conservation Biology?
•A recent response to the wave of global environmental change that is threatening to extinguish a tremendous portion of the world’s biological diversity
•Critically endangered mammals: increased from 169 to 180 in past 5 years
•24% of world’s mammal species threatened
•11,046 species of plants and animals threatened
•In past 500 years, 816 species extinct
•103 bird species extinct in the past 200 years
•Current extinction rates are at least 1,000 times normal extinction rate
Conservation Biology differs from other biological sciences
•It is often a crisis discipline
•i.e., one often has to act before knowing all the facts – thus, a mixture of science and art
Conservation Biology is interdisciplinary in nature
Interdisciplinary
Conservation versus preservation
The evolutionary history of extinction
•Almost 99% of the species that one time existed have become extinct
–Mass extinctions
•Extinction is usually compensated for by the creation of new species
•Overall diversity has increased
Extinction now
•Extinction rates are currently 1,000 to 10,000 times “background” extinction rates
•As much as 20% of current biodiversity may be lost by 2050
•Humans are primary cause of extinctions today
Anthropogenic extinctions
•In recent history, extinction is almost invariably associated with human colonization of unoccupied areas
Extinction in North America
•Megafauna
New Zealand
Historical extinctions
•Since 1600, 113 species of birds and 83 species of mammals are known to have gone extinct
Extinction in Hawaii
•Islands are particulary sensitivle to extinction
•39 species of endemic birds present before the arrival of the Polynesians had disappeared by the time of European contact
•Due to hunting, habitat loss and exotic species (rats, pigs)
Why is this extinction event special?
•Only mass extinction triggered by a single species
•Long time for recovery
•Biodiversity may not rebound due to habitat destruction
Endemism
•Endemic: a species found in a particular region and nowhere else
•Levels of endemism high for areas that have been isolated for long periods of time, especially islands
18 regions of high endemism
Hotspots
•World Conservation Monitoring Network assessed geographical regions according to:
–total species richness (biodiversity)
–proportion of endemic species
–extinction risk
Hotspots
•Identified “hotspots” contain:
–44% of the world’s known species of plants
–28% of the birds
–30% of mammals
–38% of reptiles
–54% of amphibian species
•All in an area of 1.4% of the world’s total land surface!
Biodiversity hotspots
Why do we care about losing biodiversity?
•Direct economic value
•Indirect economic value
•Ethical and aesthetic values
Benefits of biodiversity
•Food
–As many as 80,000 edible wild plant species could be utilized by humans
Agriculture
Benefits of biodiversity
•Drugs and medicines
–40% of all prescriptions contain some natural product
–Pharmaceutical companies actively prospect tropical countries for products
–Rosy periwinkle
Use fees
–USFWS estimates Americans spend $104 billion annually on wildlife-related recreation
–Ecotourism can be an important form of sustainable economic development
Benefits of biodiversity
•Ecological benefits
–Soil formation, waste disposal, air and water purification, nutrient cycling, solar energy absorption, and biogeochemical and hydrological cycles all depend on biodiversity
•Can a system function without all its integral parts?
Benefits of biodiversity
•Aesthetic and cultural benefits
–Cultural diversity inextricably linked to biodiversity
–Existence (intrinsic) value
Where are all the frogs?
Why we care
•Anurans are a part of the planet’s biodiversity
•Anurans are a large component of many ecological systems
•Anurans provide benefits to humans
Frogs as indicators
•Double life--amphibious
•Permeable skin
•Absorb and concentrate toxins--biomagnification
External malformations
•extra or missing limbs
•branching limbs
•spikes or protuberances
•missing eyes
•abnormal webbing
Internal malformations
•reproductive
•digestive
•urinary
Causes of malformations
•genetic origins
•parasite disruption of limb formation
•chemical contamination
•viruses
•ultraviolet radiation
•physical trauma (predation,
• people)
•Trematode (flatworm) cysts have been demonstrated to cause problems in limb bud development in tadpoles
Possible chemical contaminants
•agrochemicals
•heavy metals
•acid rain
•chlorofluorocarbons (CFCs)
Habitat degradation
•Loss of habitat from filling in wetlands to create more farmland for crops, and to build more houses and roads
•Nutrient enrichment of breeding ponds
Where have all the frogs gone?
•A concern during the past twenty years
•Frog declines widespread and well-documented
•Possible causes include habitat destruction, increased UV radiation, global warming and chemical contamination
Chytrid disease