Exam 3 Conservation Biology (Unfinished)

What are the 5 types of extinction?

1) Extinct - no member of the species remains alive anywhere in the world

2) Locally extinct or Extirpated - no longer found in an area that individuals
once inhabited Ex. gray wolf occurred throughout North America but is
locally extinct in many states

3) Ecologically extinct -numbers of the populations are reduced to a point
where its effects on other species in the community are negligible Ex. tigers

4) Extinct in the wild –individuals of a species remain alive only in captivity
Ex. Franklin tree is only found in cultivation

5) Globally extinct –extinct in the wild throughout the world
Ex. Montverde golden toad and the Franklin tree also fit this definition

What five reasons are species most vulnerable for extinction?

1) Species that have a very narrow geographic range
Ex. venus flytrap is only in the savannas of the coastal plain in Carolinas
-many island species fit this definition
-fish confined to a single watershed (desert pupfish)
-similar to endemic but not all endemic species are rare

2) Species with only one or a few populations.
-particularly subject to chance factors in causing extinctions
-linked to #1 as would have a narrow geographic range also
Ex. Black footed ferret with only one wild population in Wyoming in 1981

3) Species in which population size is small.
"Small population paradigm“
-one of best predictors of extinction rates of isolated populations (Have a lack of genetic variation)
-Bogor Botanical Garden in Java (SE Asia) is a arboretum that has been isolated for 50
years and only 25% of birds that had small population sizes from 1932-1952
survived into 1980s, whereas all the species that were initially common survived

4) Species in which population size is declining
“Declining population paradigm”
-first articulated by Darwin
-true of many species today and unless trends are reversed many will be lost

5) Species that are hunted or harvested by people
-often occurs in species where hunting/harvesting is not regulated by law or tribal
custom
Ex. bison, passenger pigeon, several cactus species, American ginseng

What is an endemic species

Endemic species -species naturally found only in a single geographic area
-expansions caused by humans are not considered part of the species natural
distribution

Example of a hot spot for endemism is Madagascar

What are the extinction rates of aquatic species?

Watershed: Final location of runoff

More industrialization/shipping results in more extinction

Extinction rates in oceans appear to be low but this is likely an
underestimate as these areas are often poorly known and/or marine
species may be able to adapt to disturbance well

What are metapopulations and subpopulations

Metapopulation: population divided into discrete subpopulations
linked by movement of individuals.

Subpopulation: because the landscape is heterogeneous, individuals
can form smaller groups, with much less interaction between groups
than if the habitat were homogeneous.

What are the four traits of metapopulations

1. The suitable habitat occurs in discrete patches that may be occupied
by local breeding populations.
2. Even the largest populations have a significant risk of extinction.
3. Habitat patches must not be too isolated to prevent recolonization
after local extinction.
4. The dynamics of local populations are not synchronized (all
populations move together).

Metapopulations are a balance between colonization and extinction.

What Two important phenomena prevent habitat fragments from
conforming to island biogeography theory:

1. Habitat diversity may be more important than area. This
is true on oceanic islands as well, but the effect seems to be
magnified in habitat fragments.
2. The formation of a habitat fragments create an “edge
effect”. This refers to a change in physical and biological
characteristics of a habitat as one moves from the edge to
the interior (core of the fragment).

What is the edge effect?

Refers to a change in physical and biological characteristics of a habitat as ones moves from the edge to the interior (core of a fragment)

Those at the edge have a greater potential for disease due to contact with domestic animals, and are also under the effect of a microclimate. Less humidity, increase variance in temp, higher chance of fire… etc.

What are the 10 categories of species closely linked with extinction?

1. Species that need a large home range.

Higher chance of the event effecting the range, More chance of overlapping territory 

2. Animal species with a large body size.
-have large home ranges, require more food, and are more easily hunted by
humans. More often charismatic species. 

3. Species that are not effective dispersers. (Species that do not move)

Environmental changes by humans are not fast enough that adaptation may be prevented and migration is the only solution.

4. Species that are seasonal migrants.
-depend on two or more distinct habitat types. If either is damaged, the species
may be unable to persist 

5. Species with little genetic variability.
-genetic variability may allow for adaptation to change. When it is low it can
lead to extinction

6. Species with specialized niche requirements.

7. Species that are characteristically found in stable, pristine environments

These species will be more “soft” unable to react to change in stability. 

8. Species that form permanent or temporary aggregations.

allee effect-inability of social animals to forage, find mates, or defend territory when
populations are small

9. Species that evolved in isolation and had no prior contact with people

They don’t recognize people as a threat, so they are more vulnerable to hunting. They are also exposed to species that people bring.

10. Species that have closely related species that are recently extinct or are threatened
with extinction. characteristics that make certain species vulnerable are often shared by related species

Conservation Categories

Least Concern: Unconcerned. Either as a high population or his habitats generalists. doing fine.

Lower Risk Conservation Dependent: Not at risk but may be of interest to conservation

Near Threshold: Almost threatened but not there. May be facing population decline. Less then 30%

Vulnerable: Less than 50 %. Over 10 years or 3 generations

Endangered: Less than 70 %. Over 10 years or 3 generations

Critically Endangered: Less than 90 %. Over 10 years or 3 generations

developed by the International Union
for the Conservation of Nature
(IUCN)
-developed categories based on
available data
1) observable decline in numbers
2) range of species
3) total number of mature individuals
4) expected decline in number of
individuals if the population
decline or habitat destruction
continues
5) probability of extinction in a
certain amount of time

What is the U.S Endangered Species Act of 1973

Basics of the law:
-to "provide a means whereby the ecosystem upon which endangered and threatened
species depend may be conserved [and] to provide a program for the conservation of
such species"
-by law, endangered and threatened mean the following:
1) endangered-those likely to become extinct as a result of human activity and natural
causes in all or a major portion of their range
2) threatened- those likely to become extinct in the near future

What is the biggest threat to species and biodiversity

1) Habitat Loss
2) Habitat Fragmentation
3) Habitat Degradation and Pollution

How does Urbanization effect habitat loss

More people and growth results less biodiversity as there is an overconsumption of resources.

Long term urbanization is not sustainable in the long run

How does agriculture effect extinction?

Results in habitat loss for numerous species as deforestation occurs. This generally occurs among grass lands. 

What is desertification?

Man made deserts created by habitats being degraded by people - not an actual desert just the apearence of deserts caused by a loss of soil.

What are the causes of the loss of population among coral reefs.

pollution that often causes algal blooms that when they die off and
decay, remove oxygen from water killing reef life
• sedimentation following deforestation

Overharvesting

What are habitat fragmentation

Process where large areas of continuous habitat is reduced in area creating fragments of habitat

Differ from the original habitat in two ways
1) fragments have a greater amount of edge per area of habitat
2) center of each habitat is closer to an edge

Consequences of Habitat fragmentation

1) Certain species may not have enough room to live and breed
2) potential for dispersal and colonization is often reduced
3) reduces foraging ability of animals
4) increases rate of population decline and extinction by dividing an existing widespread
population into two or more subpopulations that are more vulnerable to inbreeding
depression and genetic drift (allele frequencies changing by chance)
5) Edge effects-changes in microclimate, incidence of fire, interspecific interactions, and
potential disease along fragment edges

What is overexploitation 

-some traditional methods of hunting and harvesting are sustainable because the
people placed restrictions on the harvest
-as technology increased, overexploitation has increased and threatens many
vertebrate species. Ex. Intensive harvesting of fish
-in Africa there is a bushmeat crisis as populations of mammals are reduced 80%
by intensive hunting so the meat may be sold
-today, the worldwide trade in wildlife is valued at over 10 billion dollars per year
(excluding timber (75 billion) and fish (100 million tons per year)

What are the reasons for exploitation/Social Dilemmas

Social dilemmas are situations in which individuals make decisions in
their own self-interest that have inferior outcomes compared to what
they would have achieved by cooperating with others. Social dilemmas
are a common explanation for why individuals overexploit natural
resources to their own long-term detriment. This figure shows the
“payoff matrix” for two common social dilemma scenarios. Numbers
in the cells represent outcomes from–3 (worst) to 2 (best)

Social Dilemmas are connected to the Tragedy of the Commons. Individual self-interest results in the loss of species and biodiversity. 

Solutions to Overexploitation?

1. Link conservation of biodiversity with local economic development
   2. Establish protected natural areas where species are overexploited
   3. Strict and enforced laws regulating hunting and harvesting

What is Stakeholder participation?

Why do people become engaged in wildlife-use activities?
 Why do they continue to participate or stop participating?
 How can participation be influenced?
The above questions are linked to the idea of “satisfaction” – is a user satisfied
that their needs/wants are being met and/or their contribution is appreciated –
this impacts the recruitment/retention of uses

What are invasive species?

-species that increase in abundance at the expense of native species
-often exotic species, which are species that occur outside their natural
ranges because of human activity
-invasive exotic species threaten about 40% of endangered species in
USA with damages and losses totaling 120 billion per year
Common water hyacinth, an invasive, exotic plant

What is the typical process of biological introductions?

1. purposeful introductions that got out of control:
a) Settlers arriving at new colonies introduced hundreds of species of
mammals, birds, and fish to make the countryside more familiar and
provide game and fish
b) Large numbers of plants were introduced as agricultural or ornamental
species as well as soil stabilizers
c) Genetically modified organism
(GMO)

What are source and sink populations?

A source population is defined as a patch that provides a net donation of immigrants to nearby patches with lower-quality habitat. A source population should persist indefinitely, even in isolation.

A sink population is defined as a patch that would go extinct
if it were not for the constant input of immigrants from nearby source populations.