Biogeography Final Exam

What are major limiting factors on human population?

Food - Thomas Malthus 1798

Disease - plague 1300s

What are minor limiting factors on human population?

Predation

Wars/homicide

What developments removed the main constraints on human population?

modern medicine and agriculture (1850-1950)

What is the current human population?

8 billion

What is the percent growth of the human population?

0.9%

What is the doubling time of the human population? How is this calculated?

~75 years

70 / % growth

What is the global fertility rate, and what is the range by country?

Global fertility rate: 2.3

Range: 1.5-5, stable 2.1

What is the population projection for 2100?

10.5 billion

T/F: The human population has nearly doubled from 1975 to 2025.

True

When considering the carrying capacity of Earth for humans, what are some questions that should be asked?

Do we want:

1. only humans and food supply, or other things?

2. “first” world resource use, or low-resource use?

3. quality vs quantity, and a sustainable population

Define “just in time delivery”

materials brought just in time for use

Humans need food, water, and space, and so does all other life. How is this typically managed?

parks and reserves

What are the three major drivers of habitat destruction?

housing, agriculture, commercial

What system existed prior to formal agriculture? How much disturbance did it cause?

hunter/gatherer - minimal disturbance

What are some methods associated with plant farming?

Slash and burn

Animal and plow

Mechanical

What parts of plant farming does machinery take part in? Describe some issues associated with mechanical farming.

ground preparation, planting, and harvest

irrigation, fertilizers, pesticides, structures

What are some issues associated with industrial animal ranching?

density, antibiotics, cages, feed lots, crowding

What are some examples of modern aquatic ranching?

Salmon - ponds, partial free range

Catfish, shrimp - ponds

Commercial land use has a large foot print. List examples.

factories, mining, logging, shopping/sports, roads, dams

What are factories responsible for?

production of various goods and services

Describe strip mines, as well as underground mines.

strip mines: remove surface layer

underground mines: dig/bore shafts/tunnels

Why has there been a major push for rare Earth metals? What do these require?

used in electronics

require large mining operations

What are issues associated with mining?

waste mine debris, contaminated water

What are 3 common logging practices?

selective cut, shelter cut, clear cut

Describe selective cut logging.

individual trees are picked

least damage

Describe shelter cut logging.

small continuous patches cut

trees left intact between cut patches

Describe clear cut logging.

Very large areas cut to the ground

most damage to forest and greater ecosystem

What are some issues associated with logging?

water runoff and logging roads

Commercial land use has a large foot print. Provide examples

shopping and sports

T/F: Roads, or actual paved surface area, provide access to undisturbed areas and are the start of all habitat destruction

True

What are some issues associated with dams?

river blockage, habitat change up and down river, stop movement of animals

Describe habitat loss vs habitat fragmentation

habitat loss: all gone

habitat fragmentation: patches

What are some important characteristics of habitat fragments?

size, shape, distance, and connectivity

Do larger or smaller habitat fragments typically work better?

larger

How does shape impact habitat fragments?

edge effects (less useful area) occur in narrow fragments

Explain distance in regard to habitat fragments.

distance: how far from large undisturbed areas and other fragments

closer proximity is better

Explain connectivity as it relates to habitat fragments.

connectivity through corridors, allowing fragments to interact

connected fragments work better

Population crash

numbers go down, often to critical levels

Range collapse

area occupied shrinks

T/F: population collapse and range collapse often occur at the same time

true

Issues and characteristics of minimum viable population

• issues: genetic bottle necks and long-term persistence

• must have enough individuals for genetic success and prevent extinction

therefore, enough habitat area to support the minimum viable population is necessary

Direct removal

killing or removing individuals from natural environment

ex: hunting, fishing, collecting, pollution (unintentional)

Subsistence hunting/fishing

just what you eat, and necessary

types of hunting

subsistence, furs, sport

issues with hunting

black market and poaching

• bushmeat: wild animal meat

• pet meat

• animal products: horns, tusks, scales

types of fishing

subsistence, sport, commercial

Define commercial fishing and list the major types

large scale for food distribution

long line, seine net, gill net, trawl, trap

long line fishing

0.5 miles or more lines of hooks

seine net fishing

large nets that encircle fish

most damaging to fishery due to large removal of target species

What type of commercial fishing is most damaging to fisheries? Which is the least damaging?

most damage - seine net

least damage - trap

gill net fishing

physically trap fish by running into the net

trawl fishing

bottom or midwater, small net behind boat to catch fish and shellfish

trap fishing

small box traps for fish, crabs, lobsters

least damaging to fishery

issues associated with commercial fishing

by catch - untargeted sp. caught

lost gear - pollution, continues fishing

entanglement - trap non-target animals

poaching - fishing in protected areas

types of collection (direct removal)

pet trade - illegal wild harvest, damage to rare species

scientific - small # for scientific research

types of pollution (unintentional, direct removal)

trash ingestion

entanglement

chemicals

long-term (decades) indirect effects from exposure

chemical pollution (unintentional, direct removal)

poison

causes endocrine changes

biomagnification across the foodweb - more accumulates at higher trophic levels

Laws/regulations/interventions have worked in some cases for issues related to direct removal through _______, more that other types of human disturbance.

hunting

ex: bison saved

human activity moves sp. to areas they couldn’t normally get with what characteristics?

long distance, short time spans, numbers large enough to establish population

T/F: Invasive species are affected by human population size, but not as tied to it as habitat destruction and direct removal

true

what are the 3 possible outcomes of moving species?

die out (more likely w/ small #s), naturalized, or invasive

What does naturalization mean (invasive sp.)

become part of new area w/o causing problems

define invasive

expansion of invasion at the loss of native sp.

characteristics of invasive sp. that lead to negative effects

absence of predators and diseases

better competitor

new niche to start with

example of accidental transport and accidental release of invasive sp.

most marine, some inverts, some plants

example of purposeful transport and accidental release of invasive sp.

gardens, pets, agriculture

example of purposeful transport and purposeful release of invasive sp.

sport stocking, habitat modification, biocontrol

means of transport for invasive sp.

ships, trains (box cars and cargo), planes (cargo and wheel wells), cars and trucks (on/in body)

What means of transport poses the biggest problem in regards to invasive sp.

ships - on hulls, cargo holds, ballast water

invasive sp. control - prevention

border and cargo inspections

(>300 US shipping ports)

invasive sp. control - eradication

physical removal/killing (trapping, hunting)

chemical killing

invasive sp. control - biocontrol

biocontrol - try to “naturalize” or reduce #

release predators, parasites, diseases, or genetically modified individuals to interact w/ invasive sp.