Lecture 16: Preserving Biodiversity

Covers Chapter 30

Vocabulary

• Conservation Biology: branch of biology dedicated to understanding and preserving Earth’s biological diversity

• Biodiversity*: the variety of living organisms on Earth

Preserve diversity at different levels*

• Conservation biologists are striving to study and preserve biodiversity at different levels:

– Genetic diversity: survival of a species depends on variety of alleles in each species gene pool

– Species diversity: variety of different species that make up a community are important for survival of the community

– Ecosystem diversity: variety of both communities and the nonliving environment on which communities depend

Ecosystem services*

• The ecosystem serves HUMANS!

– Purify the air and water: forests absorb CO2, return water to the atmosphere

– Replenish oxygen: Forests produce O2

– Detoxifying wastes: bacteria in soil recycle nutrient

– Controlling erosion and flooding: plants block wind and roots stabilize soil

– Controlling pests: many organisms eat pests

– Provide recreation: coral reefs, rain forests, national parks

– Regulate climate: Trees, forests provide shade, reduce temps

Is biodiversity diminishing?

• Biodiversity is crucial to the ability of ecosystems to provide their services– *Redundancy hypothesis: if a few species are

eliminated, the remaining species in that ecosystem may be able to provide the same services to maintain that ecosystem

– BUT if that ecosystem is stressed, remaining species may not thrive well enough to provide any services

Extinction

• A natural process

• Elimination of an ENTIRE species*

• We have had 5 mass extinctions on earth, the last one 65 million years ago (dinosaurs)

• Sudden changes in the environment seem to cause them

• Some believe we are headed towards the sixth!

Scientists Warn of Next Possible Mass Extinction

• You Tube: Fox News Insider

IUCN: International Union for Conservation of Nature

• Publishes lists of at-risk species

– Critically endangered

– Endangered

– Vulnerable

– Threatened

• Totals for all lists:

– Mammals 25%

– Birds 13%

– Amphibians 41%

– Trees 41%

The Most Endangered Species List

• You Tube: SourceFed

We are depleting biodiversity

• Increasing use of resources to support humans

• Direct impact of human activities on biodiversity:*– Habitat destruction– Overexploitation of species (hunting, etc)– Pollution– Global warming

How are we depleting biodiversity?

• Ecological footprint: estimate of the area of Earth’s surface required to produce resources we need and absorb wastes we make

• Biocapacity: estimate of sustainable resources and waste-absorbing capacity (given in area)

• In 2005, footprint was 6.7 acres PER PERSON but biocapacity was 5.2 acres PER PERSON!

Human Demand Exceeds Earth’s Estimated Biocapacity

Fig. 30-6

world biocapacity

human footprint

Habitat Destruction

• Temperate forests are rebounding from our destruction, but tropical rain forests are being cut down 50,000 square miles per year…why?– Converted to agriculture to supply us with

• Beef

• Coffee

• Soybeans

• Sugar

Overexploitation

• Hunting or harvesting natural populations at a rate that exceeds their ability to replenish their numbers– Some scientists say that 70% of (edible) fish

are overexploited

Pollution

• Mining

• Burning fossil fuel

• Pesticides

• All release chemicals into the air, water and soil

What can be done?

• Core reserves and wildlife corridors

• Sustainable development

• Sustainable agriculture

Core Reserves/Wildlife Corridors

• Core Reserve: protected natural areas that exclude all but low-impact human activities

• Wildlife Corridors: strips of protected land that link core reserves and allow animals safe passage between habitats separated by human activities

Corridors Connect Reserves

Fig. 30-11

corereserve

corereserve

smallreservebuffer zones

corridors

Wildlife Corridors Connect Habitats

Fig. 30-12

Sustainable Development

• Resource use aims to meet human needs while ensuring the sustainability of natural systems and the environment.

• Biosphere reserves are areas on Earth where scientists are maintaining biodiversityand evaluating techniques for sustainable development

Biosphere Reserves divided into 3 areas

– Central core: protected area at center of reserve. Animal monitoring and LOW-IMPACT development only

– Buffer zone: research is carried out on how to preserve biodiversity, tourism, education, and LOW-IMPACT development only

– Transition area: development, tourism, sustainable fishing and agriculture only

– THERE ARE 530 BIOSPHERE RESERVES IN 105 COUNTRIES TODAY!

A Unique Biosphere Reserve

Fig. 30-14

Sustainable agriculture*

• No-till: leaves remnants of harvested crops in field to form mulch for next year’s crop

• Use animal waste to fertilize fields

• Modern irrigation that will reduce evaporation and delivers water only where and when needed

• Alternate crops and plant wider variety of crops to reduce insect infestation

What can you do?

• Recycle

• Reduce Fossil Fuel Usage

• Reduce the impact of meat consumption

• Educate yourself and others

• Vote