Maintaining Biodiversity Why is biodiversity necessary for a healthy ecosystem? What are some methods used to preserve biodiversity?

Biodiversity (BD): variation of different species within an ecosystem.

Niche: role and position that a species has in an ecosystem Niche: role and position that a species has in an ecosystem. Examples: decomposers, seed dispersers, various herbivores and consumers.

Why is more biodiversity good Why is more biodiversity good? Greater BD increases ecosystem health by ensuring more niches are filled by species.

What would happen If there were only 1 type of producer in an ecosystem and a virus reduced the population of this plant species? Turn and discuss.

What would happen If there were only 1 type of producer in an ecosystem and a virus reduced the population of this plant species? With no other herbivores to serve as a food source, the food chain would break down. Extreme example.

What would happen if there were only 1 type of herbivore and this herbivore were wiped out? Turn and discuss…

What would happen if there were only 1 type of herbivore and this herbivore were wiped out? Secondary consumers may decrease in number as well as number of producers.

Examples: starfish, alligators, otters, Galapagos tortoise Keystone species: species with large impact on ecosystem compared to its abundance. Examples: starfish, alligators, otters, Galapagos tortoise

Cascade: a succession of events originating from a first event.

The removal of a keystone species would cause a trophic cascade The removal of a keystone species would cause a trophic cascade. Trophic cascade: disturbance of lower trophic level biomass in response to the removal of a predator.

Threats to biodiversity: habitat Loss, desertification, deforestation, wildlife trade, and overexploitation.

Habitat Loss: greatest threat to biodiversity Habitat Loss: greatest threat to biodiversity. Habitat cleared for agriculture, housing, roads, and industrial development.

Desertification: process of fertile land becoming desert, typically as a result of drought, deforestation, or inappropriate agriculture.

Deforestation: clearing of forest area typically for non-forest use.

Impetus for deforestation: ranching, farming, logging for timber (wood).

Logging contributes to overexploitation of flora – trees cannot grow as quickly as they are cut. Indigenous: occurring naturally in a particular place Fauna: indigenous animals. Flora: indigenous plants.

Impacts of deforestation: decreased O2, increase CO2, disruption of H2O cycle.

Disruption of water cycle. How Mr. Allen Disruption of water cycle? How Mr. Allen? Transpiration: evaporative loss of water through leaves. With fewer trees, less water is pulled out of soil and into the air.

Soil erosion and mudslides are the result.

Wildlife Trade: Millions of organisms are harvested and sold as food, pets, ornamental plants, leather, tourist curios, and medicine.

Methods of maintaining biodiversity: ecotourism, forest conservation, wildlife management, ecological islands.

Ecotourism: tourism directed towards threatened, natural environments, to support conservation efforts.

Forest conservation methods: clear cutting, selective cutting, shelter wood cutting.

Clear cutting: a harvesting and regeneration technique that removes all trees, regardless of size, of an area in one operation.

Clearcutting promotes the growth of smaller trees that were beneath the canopy.

Selective Cutting: Only specific trees are cut down Selective Cutting: Only specific trees are cut down. Supports more varieties of wildlife than clearcutting. More resistant to disease, insects. Leaves a lighter ecological footprint.

Shelter wood cutting: forest cuttings leading to the establishment of a new generation of seedlings.

Afforestation: establishment of forest in an area with no previous tree cover.

Reforestation: the natural or intentional restocking of existing forests and woodlands that have been depleted, usually through deforestation.