1. Wildlife, Fisheries, and Endangered Species
Unit 3 AP Environmental Science (Chapter 14)

2. What are we trying to save?
1. A wild creature in a wild habitat, as a symbol to us of wilderness.
2. A wild creature in a managed habitat.
3. A population in a zoo.
4. Genetic material only.

3. Single-Species Wildlife Management
Conservation and management often viewed each species as a single population in isolation.
Assumptions:
The population could be represented by a single number, its total size.
Undisturbed by human activities, a population would grow to a fixed size, called the “carrying capacity”.
Environment, except for human-induced changes, is constant.

4. Single-Species Wildlife Management
This perception is illustrated by the S-shaped logistic growth equation.
Two goals resulted:
1. For a species we intend to harvest: maximum sustainable yield
2. For a species we intend to conserve: remain at its carrying capacity

5. Single-Species Wildlife Management
This approach failed.
None of the assumptions were true.
Population cannot be represented only by a single number.
Do not remain at a fixed carrying capacity.
The environment is not constant.

6. Single-Species Wildlife Management
Necessary to include an ecosystem and landscape context for conservation and management.
New goals:
For a species to be harvested: sustain a harvestable population in a sustainable ecosystem
For a species that is threatened or endangered: minimum viable population

7. Logistic Growth Includes the following ideas:
A population that is small in relation to its resources grows at a nearly exponential rate.
Competition among individuals in the population slows the growth rate.
The greater the # of individuals, the greater the competition and the slower the rate of growth.
Eventually, a point is reached, called the “logistic carrying capacity”.

8. Carrying Capacity Has three definitions.
1. Logistical carrying capacity- the # of individuals is just sufficient for the available resources.
2. An abundance at which a population can sustain itself without any detrimental effects that would decrease the ability of that species to maintain that abundance.
3. Optimum sustainable population- the max population that can be sustained indefinitely.

9. Maximum Sustainable Yield
Maximum number of organisms that can be harvested from a population and maintain population size
Exactly one-half of
the carrying capacity.
Over estimating MSY
will lead to overharvesting.

10. Maximum Sustainable Yield

11. The Grizzly Bear An endangered species
US Fish and Wildlife Service must meet the requirements of ESA to restore the population
Became endangered as a result of hunting and habitat loss.
Removed because dangerous to humans and livestock

12. The American Bison Brought close to extinction for 2 reasons
Hunted to make coats that were fashionable in Europe.
Killed as part of a warfare against the Plains peoples.

14. The American Bison Bison have recovered Profitable for ranchers
Currently 200, ,000 Bison
Estimates of original herds range from 10 – 50+ million
After Civil War protest over the slaughter
15 years later only 1000+/- remained

15. Improved Approaches to Wildlife Management
Four principles of wildlife conservation
A safety factor in terms of population size, to allow for limitations of knowledge and the imperfections of procedures.
Concern with the entire community of organisms and all the renewable resources.
Maintenance of the ecosystem of which the wildlife are a part.
Continual monitoring, analysis, and assessment.

16. Improved Approaches to Wildlife Management
Principles broaden the scope from a narrow focus on a single species to inclusion of the ecological community and ecosystem.

17. Time Series and Historical Range
Time series- set of population estimates over a number of years.
Historical range variation- the known range of abundance of a population of species over some past time interval (rarely available)
Analysis of these two trends show the probability of extinction for a species

18. Age Structure Information
Shows the number of organisms in various age ranges so predictions can be made about the future of a population
E.g. salmon from the Columbia River, WA
Shift in catch towards younger ages, along with an overall decline in catch, suggests that the fish were being exploited to a point at which they were not reaching older ages.
Early sign of overexploitation

19. Harvest Estimates
Another method of estimating animal populations is to use the number harvested.
Previous animal abundance can also be estimated by catch per unit effort
Assumes same effort is exerted by hunters/harvesters per unit time as long as they have the same technology (Ex: same equipment used)
If you know the total time spent hunting/harvesting and the catch per unit effort, you can roughly estimate total population

20. Fisheries Fish are an important food source 16% of the world’s protein
In developing countries fish make up much larger percentages of the average diet
Global fish harvests are on the rise
Japan, China, Russia, Chile and the United States dominate fisheries
Continental shelves make up only 10% of the ocean ecosystem but provide 90% of fish harvested

21. Continental Shelves
Fish are abundant where food resources are abundant, like places of high algae growth
Algae grow best in environments that have high concentrations of chemical elements like Nitrogen and Phosphorus
Upwelling along coastlines and on the continental shelves keep up the steady supply of chemical nutrients

22. Global Fisheries

23. Fisheries
The world’s fish harvest has increased greatly since the middle of the 20th century
Increase in number of boats
Improvements in technology
Increases in aquaculture production

25. Aquaculture
Fish harvest numbers more than doubled from and nearly doubled again from largely due to increases in aquaculture
Aquaculture currently provides more than 1/5 of all fish harvested

26. Fisheries
Current trends from the catch per unit effort show evidence that fish populations are declining
Suggests fishing depletes fish quickly
Shows about an 80% decline in 15 years
Large predatory fish are currently at less than 10% pre-industrial levels
Commercial fisheries are mining a resource not sustaining it.

28. Chesapeake Bay Estuary
Largest estuary in the United States
Drains an area from New York to Maryland including 48 major rivers and 100 smaller ones
Famous for oysters and crabs
Breeding and spawning ground for many commercially valuable species
Complex food webs
Heavily influenced by runoff, exotic species, development, and alteration in salinity

29. Chesapeake Bay
The bay area is being studied by ecologists to try and determine what environmental factors have led to the changes in fish species native to the estuary
Many issues have arisen from the past management systems (based largely on the logistic curve model), and the open resource nature of fisheries (“tragedy of the commons”)
Fishing gear also damages ecosystems. Trawling disturbs the sea floor while net and line fishing fail to catch just the target fish

30. Can fishing be sustainable?
Few wild biological resources can sustain a harvest at a level that meets even low requirements for a growing business.
We can turn to farming fish (aquaculture)
Important food source in China, growing worldwide
Can create environmental problems
E.g. Atlantic salmon fisheries cause water pollution from excrement and excess food, and can lead to a loss of genetic diversity. In 2000 Atlantic salmon were put on the endangered species list.

31. Current Status of Endangered Species
The number of species listed as threatened or endangered is increasing
International Union for Conservation of Nature maintains a list of endangered species called the Red List
21% of all known mammals at risk
12% of birds
28% of reptiles
30% of amphibians
37% of freshwater fish
35% of invertebrates
70% of plants

32. Current Status of Endangered Species
The term endangered species as defined by the Endangered Species Act of 1973
“Any species which is in danger of extinction throughout all or a significant portion of its range…”
With the exception of insect pests
The term threatened species
“Means any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.”

33. CITIES legislation
Convention on International Trade in Endangered Species (1975)
Legislation that ensures that international trade in plant and animal life does not threaten the survival of the species in the wild
Believes in the ecological value of protecting all organisms, even those that are valued for economic reasons

34. How a species becomes extinct
Local extinction
Occurs when a species disappears from a part of its range but persist elsewhere.
Global extinction
Means a species can no longer be found anywhere

35. How a species becomes extinct
Rate of extinctions has varied over geologic time
From 580 million years ago until the industrial revolution about one species per year went extinct
Rate of evolution of new species has usually equaled or slightly exceeded the rate of extinction
Average longevity of a species 10 million years
Certain periods of time have demonstrated catastrophic loss of species or rapid evolution of species in what is called “punctuated extinctions”

37. How humans influence extinction patterns
By hunting or harvesting.
By disrupting or eliminating habitats.
By introducing exotic species.
By creating pollution.
Estimates are that 75% of the bird and mammal extinctions since 1600 have been caused by humans. This rate is 1,000 times higher than the extinction rate at the end of the Pleistocene epoch

38. Endangered Species Act of 1973
Since the U.S. Endangered Species Act was put into place conservation efforts have helped 43 species recover from “endangered” to “threatened” or removed from the list entirely
An additional 33 and possibly more species have the potential soon to recover status

39. Can species be too abundant?
Sometimes conservation efforts lead to negative side effects from the protection of species whose populations have been allowed to get too large
The Marine Mammal Protection Act of 1972 led to the improvement of many marine mammals now not allowed to be hunted
Sea lions have become so abundant in some areas that they pollute the water with their excrement and become a nuisance to human activity

40. Kirtland’s Warbler
Many species are adapted to natural environmental change.
If that change eliminated the species can become endangered
Kirkland’s warbler in Michigan
From census of the species found it to be declining
Build their nests in jack-pine woodlands that are between 6-12 years old

41. Kirtland’s Warbler
Jack-pine trees ages 6-12 have dead branches close to the ground that promote the occurrence of forest fires
After 1927 people were encourage to replace jack pine trees with economically useful species of trees in an effort to suppress fires
Only the introduction of controlled burning and allowing jack pine to grow again saved the warbler species

42. Ecological Islands and Endangered Species
An ecological island
an area that is biologically isolated, so a species living there cannot mix w/ any other population of the same species.
Mountain tops
Ponds
Real geographic islands

43. Ecological Islands and Endangered Species
Almost every park is a biological island.
How large must an ecological island be to ensure survival of a species?
Depends on species requirements

44. Using Spatial Relationships to Conserve species
Red-cockaded woodpecker
An endangered species
Nests in old dead or dying pines
Feeds on pine bark beetle which hare a pest to the tree
A new approach to conservation
Overlay a map of one’s habitat requirements over a map of the other’s
Co-occurrence can be compared and allow maintenance of all three species