1. Lecture 16 Biodiversity and Species Conservation Chapters 16, 19, 26 and 28 – (mostly)

2. What is it and how is it measured? Why are we concerned?
Biodiversity
What is it and how is it measured?
Why are we concerned?
How species diversity changes with
Time
Ecosystem complexity
Latitude
Areas of special concern –
Threats to species diversity
Floristic Provinces and conservation efforts

3. Biodiversity – What is it?
~Term first appeared in 1980’s – used in place of ‘Biological Diversity’
Aspect of Biodiversity
Ecological diversity
Genetic diversity
Phylogenetic diversity
Diversity within ecosystems:
Two components:
Species richness
Describes number of species present
Relative abundance
Percentage each species contributes to total species composition
Measure of Species Evenness

6. How is diversity measured - Species level
Species diversity is difficult to determine
Simply count species present
Many errors and biases
Use statistical index – to account for sampling error issues
Evenness in species composition
Distribution of species
Sampling procedure affects numbers detected
Many logistical factors/sources of error

9. Steep slope suggest relatively fewer species than deciduous forest
Rank Abundance Curve
Visualization of relative abundance of species in different habitats
Steep slope suggest relatively fewer species than deciduous forest

10. Quantification and Comparison of Diversity - Diversity Index
Simpson’s Index = D
– several forms are used
Probability that 2 random samples will be of same species from a sample of a community
Value 01 where 1 = same species (no diversity)
Smaller value of D corresponds with greater diversity
D = Σ(n1/N)2
Number individuals of species 1
Total Individuals all species
Summation for all species

11. Large-Scale Patterns in Terrestrial Diversity
Greater towards equator (temperature effect)
Precipitation impacts some groups
Trees
Amphibians
Increases with:
Heterogeneity of landscape
Ecosystem productivity
Higher productivity generally supported by warmer + moister conditions

14. Why is biodiversity greater is some regions than others?
Evolutionary History – ie. In tropical regions speciation has historically exceeded extinction
Resource Availability  ecosystem productivity
Climatic factors – primarily temperature and precipitation
Ecosystem complexity: diversity is self-reinforcing

15. End of Permian – loss of many shallow water invertebrates
Mass Extinction Events - Major ‘winnowing’ Events
End of Permian – loss of many shallow water invertebrates
Cretaceous: extinction of dinosaurs
Other extinctions associated with ice ages
Modern extinctions (since 1600):
Human activities
Introduced predators, parasites, exploitative hunting/fishing

17. Biodiversity and Its Self-Reinforcing Nature
Creation of additional habitats and niches
Microclimates
Increased diversity at one level (ie. producers)  increased diversity at other levels
Forces driving diversification:
Competition and predation
Co-evolution

18. Patch Size and Shape Are Crucial to Species Diversity
Patch size and shape affect the relative abundance of edge and interior environments
Only a larger patch can develop interior conditions
If edge depth remains constant proportion of patch devoted to edge increases with decreasing patch size (fig 19.9)  altered impact of ‘edge effect’

19. Species vary in terms of habitat requirement
Interior species
Edge species
Area insensitive species

22. Value of Biodiversity Interrelatedness of organisms in ecosystems
Food chain vs. food web – ecological relationships are complex; is loss of single species significant?
Value as source of resources
new medicines, etc.
Aesthetic value

23. Biodiversity Hotspots Identified by Norman Myers et al
Areas deserving special conservation efforts
25 world wide – based on:
Species concentration
High numbers of endemics
Subject to habitat destruction/human population incursion
High current popul levels + growth

25. California Floristic Province Many Rare and Endangered Species
Giant Sequoia
Giant Kangaroo Rat
California Condor
Overview:
Wide variety of habitats
sagebrush steppe, prickly pear shrubland, coastal sage scrub, chaparral, juniper-pine woodland, upper montane-subalpine forest, alpine forest, riparian forest, cypress forests, mixed evergreen forests, Douglas fir forests, sequoia forests, redwood forests, coastal dunes, and salt marshes

26. California Floristic Province
Hotspot Original Extent (km2)
293,804
Hotspot Vegetation Remaining (km2)
73,451
Endemic Plant Species
2,124
Endemic Threatened Birds 4
Endemic Threatened Mammals 5
Endemic Threatened Amphibians 8
Extinct Species† 2
Human Population Density (people/km2)
121
Area Protected (km2)
108,715
Area Protected (km2) in Categories I-IV*
30,002

27. Factors impacting Species Loss Habitat loss
Outright destruction – clear cutting, etc.
Fragmentation
Overexploitation
Toxin accumulation
Loss of keystone species
Competition with introduced species/disease
Other human activity
Anthropogenic noise in marine environments
Light pollution
Interference with migratory species

28. Solutions Reserves Restoration efforts The law Habitat
Individual species
The law
Endangered species act
International treaty
CITES (Convention on International Trade in Endangered Species)
IWC (International Whaling Comission)