1. What is Biodiversity?
• The variety of different types of organisms present and
interacting in an ecosystem.
• Often more species equals more diversity, although there are,
in fact many more factors beyond a simple count of species
that determine whether biodiversity is higher or lower in any
given ecosystem.
3. Genetic Diversity
• Amount and variety of genetic material within individuals, populations or
communities
• Source of biodiversity at all levels
• Knowledge of amount of genetic variability present within local
populations essential in directing conservation programs.
• Amount of genetic differences among species could help determine rates
of evolutionary change
4. Species Level
• Species Richness: numerical count of species present in an area. Richness
tends to increase over area and sampling intensity
• Species Diversity: When species are weighted by some measure of
importance e.g. abundance, productivity or size.
• Measures of Diversity include:
– Shannon-Wiener Index
– Simpson index
5. Shannon’s Diversity Index
• Assume that there are n possible categories in a data set and that their
proportions are pi,.....,pn. Then Shannon’s diversity index for this system is
defined to be :
• H’ = -Σpiln(pi)
• accounts for both abundance and evenness of the species present
• The proportion of species i relative to the total number of species (pi) is
calculated, and then multiplied by the natural logarithm of this proportion
(lnpi).
6. Simpson’s Diversity Index, D
• Simpson's diversity index (D) characterizes species diversity in
a community.
• Simpson's diversity index (D) characterizes species diversity in
a community.
• D = 1/(Σpi
2)
• The proportion of species i relative to the total number of
species (pi) is calculated and squared. The squared
proportions for all the species are summed, and the reciprocal
is taken.
7. Ecosystem and Biome diversity
• Ecosystems are the collection of all the plants and animals
within a particular area
• Ecosystems may differ in species composition, physical
structure and function as a result of differences in physical
structure and composition
• Biomes are large ecological units on the basis of dominant
vegetation
• Preserving a variety of ecosystems and biomes are necessary
for preserving species diversity
8. Spatial patterns of species richness
• Point Richness: number of species that can be found in a
single point in space
• Alpha (α-) richness: number of species found in a small
homogenous area
• Beta (β-) richness: rate of change in species in species
composition across habitats
• Gamma (γ-) richness: change across large landscape gradients
• Richness is directly related to physical environment,
productivity and structural complexity of communities
9. Threats to biodiversity
• habitat destruction (slash and burn agric. or felling of old-
growth forests)
• overexploitation (fishing, hunting)
• pollution (domestic and industrial emissions)
• global climate change (the greenhouse effect and destruction
of the ozone layer)
• invasion by introduced species (displacement of native
species
• underlying social conditions (increased per-capita
consumption, poverty, rapid population growth, unsound
economic and social policies )
10. Patterns of species vulnerability
• Rare Species
• Long-lived species
• Keystone species
12. Aquatic Ecosystems
• The types of
organisms that live in
an aquatic ecosystem
is determined by the
water’s salinity
• Salinity is the amount
of dissolved salts the
water contains.
– Freshwater= <0.5 ppt
– Saltwater= 30-50 ppt
• Aquatic Ecosystems
are divided into
Freshwater and
Saltwater or Marine
13. Freshwater vs Saltwater
• Freshwater
– Lakes and Ponds-Slow
– Rivers and Streams-Fast
– Wetlands-water logged
land
– Marshes and Swamps
• Saltwater or Marine
– Marshes and Swamps-
Coastal
– Coral Reefs
– Deep Oceans
14. Characteristics of Aquatic Ecosystems
• Aquatic Ecosystems are characterized by
– Temperature
– Sunlight Depth
– Oxygen Concentration
– Available Nutrients
• Aquatic Organisms are grouped by their location at
water depths and adaptations
– Plankton-Surface, provide most of food, producers
• Zooplankton-microscopic animals
• Phytoplankton-microscopic plants
• Nekton-Free swimming organisms
– Fish, Turtles, Whales
• Benthos-Bottom dwelling organism, lived attached to
hard surfaces
– Mussles, worms and Barnacles
15. Nutrients in Lakes
• Lakes with an abundant amount
of nutrients, causing
overgrowth of plants, algae and
bacteria are known as
Eutrophic Lakes
• Depletion of oxygen in these
lakes called Eutrophication-kills
off oxygen requiring organisms
• Rainwater runoff carrying
sewage, fertilizers and animal
wastes from land into the water
accelerates Eutrophication
16. Wetlands
• Areas of land covered by water for
part of the year
• 2 Types of Wetlands
– Marshes-contain nonwoody plants such
as cattails, low, flat lands, characterized
by salinity-ex. Florida Everglades
– Swamps-dominated by woody plants
such as cypress trees, low, poorly
drained land, good habitat for
amphibians- ex. Louisiana bayou
• 2 Purposes of Wetlands
– Filter and absorb water-prevents
pollutants from entering ground water
– Control Flooding-absorb river overflow
– Homes and nesting area for migratory
birds
– Cranberry, crawfish production
Wetlands are protected in many states
17. Threats to River Systems
• Industries use river water in manufacturing
processes and release waste into the waters.
• People dispose of sewage and garbage in
rivers
• Pollutants and toxins produced have killed
river organisms and made river fish inedible
• Water runoff from land carries pesticides,
fertilizers and manufacturing chemicals into
the river coating sediment with toxic waste
• Pollutants enter ground water and human
drinking water resources in rural areas.
20. services
• removal of air pollutants
• emission of oxygen
• cycling of nutrients
• an array of watershed functions (infiltration,
purification, flow control, soil stabilisation)
• maintenance of biodiversity
• sequestering of atmospheric carbon
21. services continued
• moderation of weather extremes and impacts
• generation of soil
• provision of employment
• provision of human and wildlife habitat
• provision of aesthetic enjoyment and
recreation
22. There are three major types of forests,
classed according to latitude:
• Tropical
• Temperate
• Boreal forests (taiga)
23. Tropical forest
• Tropical forests are characterized by the greatest diversity of species.
• They occur near the equator, within the area bounded by latitudes 23.5 degrees N and
23.5 degrees S.
• One of the major characteristics of tropical forests is their distinct seasonality: winter is
absent, and only two seasons are present (rainy and dry).
• The length of daylight is 12 hours and varies little.
25. What are Mangroves?
• Mangroves are plants
that grow in tidal areas.
• The word mangrove can
describe a single plant
or it can refer to a
whole community of
plants .
• They are halophytes
(‘salt loving”). Most
plants can not survive
in salty conditions.
26. Where do Mangroves Grow?
• Mangroves grow
only in the tropics
and subtropics. They
do not tolerate cold
temperatures well,
and freezing
temperatures will kill
them.
• Picture of mangroves in Sarasota Bay. K
Broderick
27. Effect of hurricanes
• Hurricanes have a
profound impact on
Mangrove communities.
Severe erosion and
wind damage can
severely restrict growth.
In severe cases areas of
mangroves can be
destroyed. The picture
shows damage to
Florida mangroves by
Hurricane Charley.
• Picture courtesy of USWF
28. Mangrove adaptations
• Did you know that
mangrove plants are
unique in that they
have live young
(viviparous). The seed
remains attached to the
parents plant until it
germinates. It then falls
from the tree and drifts
on the water until it
finds somewhere to
take root.
• Red mangrove fruits courtesy of Selby Gardens
29. Why are mangroves
important?
• The leaf detritus
also provides food
for animals such as
worms,
snails,mussels,
oysters,shrimp,
clams and mullet.
30. The Mangrove Ecosystem
• Mangrove wetlands
provide habitat,
feeding, breeding
and nursery areas
for a wide variety of
plants and animals,
including
endangered species.
Picture shows a Snowy Egret
31. Endangered Species
• Florida mangroves
support a number of
endangered species
such as
– The west Indian
manatee
– The brown pelican
– The eastern indigo
snake
– The hawksbill turtle
32. Amazing mangroves
• Did you know that
mangroves can filter
out pollutants like
nitrates, phosphates
and petroleum
based products that
are present in run-
off? The microbes in
the sediment break
the pollutants down.
33. Fisheries
• Mangroves contribute to
our economy;they have a
big influence on our
fisheries, because so
many commercially fished
species breed or develop
there. The mangroves
also provide an important
source of food for other
marine life.
• Picture shows Florida Stone crab
