Biodiversity

Environmental Science Notes Series

What is Biodiversity?

• Species Richness is another term for biodiversity

• Density is an important factor in terms of biodiversity

• Carrying capacity: resource availability is important (Tillman curve)

Niche

• The role of an organisms within its environment (habitat) that is specific.

• Gause’s competitive exclusion theory – no two organisms (populations) can occupy the same niche indefinitely (Andrews.edu).

• Niche is important in terms of competition.

Species Abundance?

• The amount of a particular species in a given habitat is important, this is abundance.

• Sometimes this does not support species richness if the species out-competes others species.

Biodiversity• According to Peter Raven (2007) there are

approximately 1.5 million known species on earth with a high extinction rate.

• There may be 8 – 10 million species on earth today, but not much is known about the lower taxa.

• Biodiversity is being impacted by humans at an unprecedented rate of extinction of up to 200 species per day.

Competition

• There are a number of ways in which a species competes for resources:1. Exploitation: this is when a species can utilize resources better than other species (i.e. Aureococcus)2. Interference: when a species can create its own environment and manipulate it for its advantage (i.e. Sour weed)

Ecology

• Ecology is a young field (started in the 1950’s), exploring the role of organisms within their environments and how it relates to survival.

• Ecology takes into account habitat, environmental factors, biological functions and physical conditions.

Population Estimates

• Use basic population models…

Interspecies: Margelef, Menhenick, Jaccard’s indices

Inter/Intraspecies: Simpson’s Index

Island Biogeography

• Robert MacArthur and Edward O. Wilson, theorized about space and resources looking at islands.

• They hypothesized that islands further from a mainland would have less species diversity than those closer.

• They also hypothesized that larger islands would support more diversity than smaller islands.

Sustaining Wild Species

• Over 90% of today’s crops are domesticated and basically 4 crop types provide a majority of the world its food requirement.

• Over 80% of the world needs plants for medicinal purposes.

Sustaining Wild Species?

• Is survival of the human species a key to survival of other species?

• We look at things from an anthropogenic view.

• It is thought that over 1 million species live in the rainforests (known) with an extinction rate of 2% per year!

Species protection categories

• Endangered – reduced mating pairs to the point where populations cannot sustain themselves (Kemp’s ridley sea turtle)

• Threatened – declining in numbers, but must be protected (Osprey)

• Concern – Decline, possibly due to habitat loss or resource limitations

Protection

• Endangered Species Preservation Act (1973):

Species are listed under Federal and Statewide basis. Therefore, they could receive protection under different categories.

American alligator – Federal

Threatened, varies statewide

IUCN: Red List Program

• The International Union for the Conservation of Nature established a program through the United Nations for global protection of species

• Under the Red List Program (www.iucnredlist.org) has a well organized system of species rankings.

IUCN Red LIST 2007

Protection

• Enforcement of the Endangered Species Act is a Federal Mandate and falls under the following…

– U.S. Fish and Wildlife Service

– National Oceanic & Atmospheric Administration, National Marine Fisheries

U.S. Fish & Wildlife

• Department of the Interior.

• Responsible for all beaches, inland waters, except Great Lakes.

• Species management, control and manage lands that are moderately-restricted (over 500 refuges and rangelands).

“NOAA Fisheries Service conserves, protects, and manages living marine resources in a way that ensures their continuation as functioning components of marine ecosystems, affords economic opportunities, and enhances the quality of life for the American public” (NOAA 2007).

NOAA

• National Estuarine Research Reserve Program

• Sanctuaries and Protected Areas (called Marine Protected Areas

• Fisheries Quotas and Enforcement

Other players in management

• Multiple Use Lands..

National Forests which include over 150 Forests and 19 grasslands managed through the U.S. Forest Service

Other players in management

• Multiple Use Lands…

• The largest is the Bureau of Land Management which includes prairies, deserts, scrub forests and open spaces mostly in the western U.S.

Other players in management

• Restricted Use Lands

The National Park Service has over 370 units and 50+ major parks throughout with close to 50% in the wilderness (www.nps.gov).