Biological Diversity Biological Diversity Biological Diversity: Evenness and Richness

Richness: the number of different organisms in a particular area (kinds of species)

Evenness: how the quantity of each different organism compares to the others (abundance of kinds of species)

Numbers of individuals

Flower Species

Sample 1 Sample 2

Daisy 300 20

Dandelion 335 49

Buttercup 365 931

Total 1000 1000

Is a community diverse if it is dominated by a single species? Why/why not?

Simpson Diversity IndexSimpson Diversity Index

A measure that takes into account richness and evenness

Formula: D =

Where:

D = diversity index

N = total number of organisms in the ecosystem

n = number of individuals of each species

N (N-1)

sum of n (n-1)

Simpson Diversity Index ExampleSimpson Diversity Index ExampleSpecies Number (n) n(n-1)

Woodrush 2 2

Holly (seedlings) 8 56

Bramble 1 0

Yorkshire Fog 1 0

Sedge 3 6

Total (N) 15 64

D = 15 (14) 64

D = 3.3

Σ n(n-1)

What does this number represent? How can it be

used?

Reasons for Conserving Reasons for Conserving BiodiversityBiodiversity Economic

Examples: rainforest soils for crops; pharmaceuticals; ecotourism

Ecological

Loss of diversity could collapse the ecosystem; diversity makes ecosystems less susceptible to invasive alien species; diversity of plant species buffers the effects of increasing greenhouse gasses

Ethical

“We do not inherit the earth from our ancestors, we borrow it from our children” Native American Proverb

Aesthetic

Nature’s beauty inspires art, gives us awe, and is connected to human cultures in countless ways

Biological ControlBiological Control

The use of an organism (introduced) to control another organism

Risks: introduced organism may not behave as expected (Cane Toads)

Benefits: introduced organism may be the only control mechanism flexible enough to be effective against another invasive with no predators

Examples

Purple loosestrife (invasive in US and Canada) – controlled by 2 species of beetles (Gallerucella)

Red Invasive Fire Ants (RIFA) (invasive on many continents) – controlled by Phorid flies

red fire ants and phorid flies video on NG.com

BiomagnificationBiomagnification The process by which chemical substances

become more concentrated at each trophic level.

[In

crease

]: 1

0 m

illio

n t

imes

CFCs and OzoneCFCs and Ozone In the atmosphere, CFCs (used in refrigerator coolants,

propellants, and foam packaging) release chloride ions.

The chloride ions react with ozone (O3) and produce ClO and oxygen gas (O2)

The ClO molecules react with atoms of O to form more O2 and free up the Cl

In this way the CFCs behave like a catalyst that doesn’t get used up and is free to destroy ozone for a century

Depleted ozone layer permits more UV radiation through the atmosphere

UV radiation causes:

Skin cancer, DNA mutation, sunburn, cataracts, reduced biological productivity, and may be related to loss of amphibian biodiversity globally

Indicator SpeciesIndicator Species AKA “the canary in the coal mine”

Organisms sensitive to environmental conditions

Examples: Lichen (air pollutions like lead/mercury), macroinvertebrates (water quality)

htt

p:/

/ww

w.p

eople

.vir

gin

ia.e

du/~

sos-

iwla

/Str

eam

-Stu

dy/M

eth

ods/

Form

.GIF

Bio

tic

Index

Biodiversity in a Nature ReserveBiodiversity in a Nature Reserve Size of the Reserve

Single large or several small sites? Single large better because small sites = small populations (greater chance for extinctions from disease/lack of genetic diversity). Small sites also have more edges (see next). Some organisms have require large territories that can’t overlap.

Edge Effect

Ecology at the edge of an ecosystem is different from the center. Edges can have more sunlight, more wind, less moisture, and fewer trees. Edge organisms may have more competition/fewer resources. Edges are more susceptible to invasive species.

Corridors

Smaller, otherwise isolated habitats, connected by corridors allow organisms to travel between them. Problems include exposure in narrow corridors, invasives, and human/animal interactions around corridors.

Management in Conservation Management in Conservation AreasAreas

Restoration: attempt to return the land to it’s natural state through various active management techniques

Recovery of threatened species: usually through habitat restoration (which helps all species ,declared threatened or not, who occupy the habitat)

Removal of introduced species: active removal of invasives such as kudzu from the US southern states or leafy spurge in the US western states

Legal protection against development/pollution/hunting

Funding and prioritizing: limited funding creates the need to make choices:

Restore the habitats of all threatened species or just the ones that make the greatest overall impact?

Remove all introduced species, or just invasives?

In Situ ConservationIn Situ Conservation

Conservation of species within their natural habitat (where they belong), such as wildlife reserves, national parks, etc…

Includes planning for improvement of biotic and abiotic factors of that habitat

Maintaining habitat (space); defense of target species from predation; removal of invasives; maintaining large populations; maintaining genetic diversity

Allows threatened species to adapt to environment with minimal interference from humans or invasives

Terrestrial reserves are common for in situ conservation, but marine aquatic reserves lag far behind

Ex Situ ConservationEx Situ Conservation

Conservation of a species outside of their natural habitat

Necessary if species is unsafe in the natural habitat, has a population too small to make a come-back, or if social/political/economic reasons make habitat protection impossible

Examples:

Captive Breeding Facilities

Botanical Gardens

Seed Banks

Captive BreedingCaptive Breeding

Zoos are the most common, most have large sections dedicated to captive breeding programs, animal husbandry experts, and money from tourism

Techniques

Artificial insemination (when necessary)

Embryo transfer to surrogate mothers

Cryogenics

Human-raised young (when necessary)

Pedigrees (to reduce inbreeding)

Disadvantages:

Captivity-bred organisms can spread disease to wild ones after re-introduction

Captivity-bred organisms lack the in situ learning and survival strategies

Botanical Gardens and Seed BanksBotanical Gardens and Seed Banks 80,000 plant species kept in private gardens, arboretums

and botanical gardens all over the world to protect and breed them

Far easier to care for plants than to breed animals

Problem: wild relatives of commercial crops are under-represented. Genes from these plants could infuse longevity into traditionally inbred crop plants (i.e. bananas)

Seed banks are keeping 10,000 to 20,000 plant species seeds in cold, dark conditions to prevent germination (for decades).