Species Diversity

1
Species Diversity
2
Questions for Today

• What is Species Diversity?
• What is the difference between Species Richness
  and Species Evenness?
• How Does Species richness affect Biodiversity?

3
What is Species Diversity?

• Species Diversity is the number of different
  species an ecosystem contains (species richness)
  combined with the relative abundance of
  individuals within each of those species (species
  evenness).
• Species Diversity is as major component of
  biodiversity.

4
What is Species Diversity?

• Species Diversity varies with their Geographic
  Location
• Terrestrial plants and animals
• Highest towards the equator and lessens as we
  head to the poles
• Aquatic Plants and animals
• Highest where there is more sun available.

5
Species Richness vs. Evenness

• A coral reef with many different types of species
  but at a low number would be described as having
  high species richness but low evenness
• A aspen forest with only aspen trees and a few
  individuals but at a high number would be
  described as having low species richness but high
  evenness.

6
Variations in Species Richness and Species
Evenness
7
How does Species Richness affect Biodiversity?

• High Species Richness creates a more stable
  environment
• More Producers
• More NPP
• More complex food chains and webs
• Allows organism to adapt to environmental
  stresses
• Able to bounce back from catastrophes better.

8
Niches and Roles
9
Questions for Today

• What is a Niche?
• What are the differences between Generalist
  Species and Specialist Species?
• What are the different roles Species can play in
  the environment?

10
Ecological Niches

• Each species in an ecosystem has a specific role
  or way of life
• Ecological Niche a species way of life or role
  in the community
• Includes everything that affects its survival and
  reproduction

11
Generalist Species vs. Specialized Species

• Some species have broad ecological roles and
  others have narrower or more specialized roles.
• Generalized species species that can have broad
  niches.
• Extremely adaptable to a changing environment
• Flies, Rats, Cockroaches, white-tailed deer,
  raccoons, coyotes, humans, and many weeds.

12
Generalist Species vs. Specialized Species

• Specialist species species that occupy narrow
  niches.
• May only live in a certain habitat, use only one
  type of food, or tolerate a certain climate
  condition.
• More Prone to extinction
• Tiger Salamanders must live in fishless ponds
• Giant Panda habitat loss, low birth rate
• Shorebirds
• Is it better to be a generalist or a specialist?

13
Roles for Organisms

• Niches can be divided into the roles species play
  in their community
• Native
• Non-native
• Indicator
• Keystone
• Foundation

14
Native vs. Non-native

• Native species are those individuals that
  normally live and thrive in a particular
  ecosystem.
• Non-native species are those individuals that
  migrate or are accidentally or deliberately
  introduced to a particular ecosystem.
• Invasive, alien, or exotic

15
Native vs. Non-native

• Non-native species can be good or bad.
• Good NN
• Cows, chickens, and other domesticated animals
• Bad NN
• Kudzu Vine, Water Hyacinth, and Killer Bees

16
Indicator Species

• When an ecosystem or community starts to
  collapse, ecologist look at indicator species for
  the first warning signs.
• Indicator species are, generally, specialist
  species that are affected by a change in one or
  more key abiotic factors in the environment.

17
Indicator Species

• Examples of Indicator Species
• Trout for water quality
• Birds for air quality
• Frogs a general measure of productivity in a
  region.
• Tropical Regions

18
Keystone and Foundation Species

• Keystone species have a large effect on the types
  and abundances of other species in an ecosystem.
• Keystone species are low in number and are
  usually prone to extinctions
• Extremely important
• Two major roles of Keystone Species
• Pollinator
• Top Predator
• Loss of Keystone Species usually lead to a
  population crash and other extinctions

19
Keystone and Foundation Species

• Foundation species play a major role in shaping
  communities by creating and enhancing their
  habitats in ways that benefit other species.
• Elephants push over trees and uproot plants to
  help new plants take root.
• Beavers create dams and cut down trees.