Review Biodiversity

Evolution Change over time Achieved by a change in a population’s genetic make-up over many generations Speciation: development of a new species - may occur when a population is isolated - may occur from hybridization (ex: crossing plants)

Human Impacts on Biodiversity Human Population Increase Human Activities Direct: Pollution Deforestation Destruction of Natural Resources Indirect: Climate Change Loss of Biodiversity

Natural Capital of Forests Ecological- purify water and air reduce erosion store atmospheric carbon Economical- lumber fuel wood jobs recreation

Effects of Deforestation Decreased fertility of soil Runoff of soil into aquatic systems Extinction of species Loss of habitat Regional climate change Release of CO2 Increased flooding

Deforestation Greatest cause of deforestation is conversion of forests into pastures for agricultural use.

Forest Management Methods Clear Cutting- lowers biodiversity and leaves a barren landscape Selective Cutting- removing some trees, leaves a forest with high biodiversity and beauty Shelter-wood Cutting- removes mature trees in groups over many years and leaving many trees to reseed the area Seed- tree cutting- removing all seed trees and leaving the large mature seed bearing trees

Sustainable Forestry Identify and protect forest areas high in biodiversity Stop clear-cutting on steep slopes Prohibit fragmentation of remaining large blocks of forest Sharply reduce road building into uncut forest areas Certify timber grown by sustainable methods Shift government subsidies from harvesting trees to planting trees

Forestry In 2003, U.S. Congress passed the Healthy Forest Restoration Act: Allows timber companies to cut medium and large trees in 71% of the national forests. In return, must clear away smaller, more fire-prone trees and underbrush. Some forest scientists believe this could increase severe fires by removing fire resistant trees and leaving highly flammable slash.

Importance of Biodiversity Stability- stable environment Genetic reserves- genetic diversity Medicinal- medicines Agricultural- food Industrial- building homes; things we use Scientific- experimental; new technology Aesthetic- beautiful Ethical- what should we do regarding the environment Religious- religious beliefs regarding environment

Extinction The current extinction crisis is the first to be caused by a single species- US! This is happening faster than ever; a few decades versus thousands to millions of years. Humans are eliminating not only the species but, the environment. Ex. Tropical rainforest

Endangered Species with so few survivors that the species could soon become extinct. Ex: Leopard

Threatened Wild species that is still abundant in its natural range but is likely to become endangered because of a decline in numbers. Ex: Northern Sea Lion

Species Vulnerable to Extinction Low Reproductive Rate Specialized Feeding Habits Feed at high trophic levels Large size Specialized nesting or breeding areas Found only in one place or region Fixed migratory patterns Preys on livestock or people Behavioral Patterns

HIPPO Conservation biologists summarize the most important causes of premature extinction as “HIPPO”: Habitat destruction, degradation, and fragmentation Invasive species Population growth Pollution Over-harvest

Ecological Restoration Restoration: trying to return to a condition as similar as possible to original state. Rehabilitation: attempting to turn a degraded ecosystem back to being functional. Replacement: replacing a degraded ecosystem with another type of ecosystem. Creating artificial ecosystems: such as artificial wetlands for flood reduction and sewage treatment.

In- Situ Leaving the animal where it lives but protecting it. Ex. Elephants- laws prevent poaching and have people in place to enforce it.

Ex- Situ Taking the animal out of its habitat & protecting it. Ex. Zoo’s 2 types: egg pulling -collecting wild eggs laid by critically endangered bird species and then hatching them in zoos or research centers captive breeding- wild individuals of a critically endangered species are captured for breeding in captivity, with the aim of reintroducing the offspring into the wild.

Invasive Species Many nonnative species provide us with food, medicine, and other benefits but a a few can wipe out native species, disrupt ecosystems, and cause large economic losses.

Protecting Biodiversity- 1972 CITIES- Signed by 169 countries, lists 900 species that cannot be commercially traded Banned all international trade in elephant products to protect elephant populations

Protecting Biodiversity- 1992 CBD- Convention on Biodiversity Calls on nations to cooperated and establish steps of action to be taken to protect the world’s biodiversity.

What can you do? Adopt a forest. Plant trees and take care of them. Recycle paper and buy recycled paper products. Restore a nearby degraded forest or grassland. Landscape your yard with a diversity of plants natural to the area. Live in town because suburban sprawl reduces biodiversity Do not buy birds, snakes, turtles, tropical fish, and other animals that are taken from the wild.